Systolic time intervals in the differential diagnosis of constrictive pericarditis and cardiomyopathy. Systolic time intervals (STI) were measured from simultaneously recorded phonocardiograms, carotid pulse tracings, and electrocardiograms in 11 patients with constrictive pericarditis and in 10 patients with cardiomyopathy to assess the value of STI in the differential diagnosis of the two conditions. The predicted ejection fraction was calculated from the STI. The results were compared and found significantly different in the two groups of patients. The ratio PEP/LVET and the ejection fraction were found to have greater discriminatory values and separated the two groups clearly. Measurement of STI, a simple, noninvasive bedside technique, appears to be useful in distinguishing between constrictive pericarditis and cardiomyopathy.


Instantaneous mitral valve leaflet velocity and its relation to left ventricular wall movement in normal subjects. Echocardiograms showing mitral valve leaflets, interventricular septum, and posterior wall of the left ventricle simultaneously were recorded at a paper speed of 100 mm/s in 20 normal subjects. These records were manually digitized and a computer was used to derive mitral valve velocity, left ventricular dimension, and its rate of change continuously throughout a single cardiac cycle. The pattern of instantaneous mitral valve velocity with respect to time was similar in all subjects studied, showing a peak opening rate of 400 +/- 60 mm/s (mean +/- 1 SD), and continuously changing velocity throughout the period of mid-diastolic closure. The peak diastolic closure rate was 250 +/- 60 mm/s and thus appreciably higher than average velocities obtained by manually measuring the slope. A close time relation existed between mitral valve and left ventricular wall movement in early diastole. Forward movement of the anterior leaflet began 1 +/- 6 ms after the onset of outward wall movement, and peak velocity was reached 2 +/- 7 ms after the maximum rate of change of dimension. Later, a discontinuity in wall movement at the end of rapid filling preceded a corresponding discontinuity in the mitral valve velocity tracing by 5 +/- 10 ms. The technique, therefore, allows continuous measurement of mitral valve velocity, and demonstrates its close relation to left ventricular wall movement during diastole.


Clinical experience with left main coronary artery stenosis. We report the clinical features and the results of investigation and surgery in 20 patients with significant left main coronary artery stenosis. All had moderate to severe angina; 8 had pain at rest. Three had dyspnoea as a major symptom. The electrocardiogram was abnormal in 17, with evidence of previous myocardial infarction in 10. Of the 11 patients exercised, 8 developed chest pain. Nine patients had a normal left ventriculogram. At coronary angiography all patients had major disease elsewhere in addition to the left main coronary artery stenosis. There were no deaths or major complications associated with this investigation. One patient was unsuitable for surgery because of diffuse left ventricular hypokinesia, one had a fatal myocardial infarction while awaiting operation, and there was one preoperative death. Sixteen of the 17 surgical survivors are free from angina. There has been a significant improvement in the maximum exercise capacity in the 10 patients who had pre- and postoperative exercise tests.


Sustained release procainamide in patients with myocardial infarction. Sustained release procainamide tablets were administered to 34 patients 48 hours after the onset of an acute myocardial infarct. Therapeutic blood levels of procainamide in the range of 4 to 8 mug/ml were consistently achieved using an 8-hourly maintenance dose of 1.5g after an initial loading dose of 2g. In contrast conventional procainamide capsules administered to 21 comparable patients repeatedly failed to produce plasma concentrations in the therapeutic range, despite the administration of a maintenance dose of 375 mg 3 hourly, after a loading dose of 1g. It is suggested that when the oral administration of procainamide is indicated for the management of ventricular arrhythmias after myocardial infarction, a sustained release preparation should be used.


Assessment of left ventricular systolic function in man from simultaneous echocardiographic and pressure measurements. Simultaneous measurements of left ventricular dimension and wall thickness by echocardiography, and of pressure by micromanometer, were made at cardiac catheterization in 30 patients with heart disease, in order to study mechanisms of impairment of left ventricular systolic function. Echocardiograms and pressure traces were digitized so that continuous measurements of left ventricular wall thickness and dimensions with their rates of change could be obtained. Ejection fraction was estimated from digitized cineangiograms. In all patients, except those with severe mitral regurgitation, there was close correlation (r=0.92) between peak left ventricular dP/dt and peak rate of reduction of dimension. Myocardial power values, calculated as the product of circumferential shortening rates and wall stress were plotted throughout the cardiac cycle, and peak values in patients with normal left ventricular function were in the range 30 to 60 mW cm-3 myocardium. Pressure-dimension loops were constructed, which reflected the relation between the function of a localized region of cavity studied by echocardiography and that of the ventricle as a whole in the pressure wave form. Incoordinate contraction was associated with distortion of the loop and a reduction in its area to less than 75% that of the maximum for the cycle in question (cycle efficiency). In patients with left ventricular disease, ejection fraction, peak power, and cycle efficiency were all reduced, either singly or in combination. There was no consistent pattern, however, suggesting that clinical left ventricular disease may be the resultant of a number of different types of disturbance. These include structural abnormalities, reduction in peak rates of myocardial shortening or power development, and incoordinate contraction. The present investigation suggests ways in which these may be separated and studied in individual patients.


Echocardiographic assessment of mitral valve calcification. The mitral valve was assessed by echocardiography in 20 patients, aged 27 to 67 years, who subsequently underwent mitral valve replacement. After removal, the mitral valve cusps were examined by direct measurement, radiography, and quantitative calcium extraction. Increased thickness of the E-F echo was found where calcification or fibrosis was present, differentiation by echocardiography alone being unreliable. However, multiple dense parallel E-F echoes were found in all 10 patients with more than 80 milligrammes of calcium in the valve, while a single thin E-F echo indicated the absence of significant calcification or fibrosis.


Failure of ST segment elevation to predict severity of acute myocardial infarction. Praecordial ST segment elevation was measured at 35 electrode positions in each of 40 patients admitted to a coronary care unit after acute transmural anterior myocardial infarction. Serial praecordial electrocardiographic maps were recorded to determine (a) the time course as well as reproducibility of measurements of ST segment alterations, and (b) the degree of correlation between the magnitude of ST segment elevation and the severity of infarction, as assessed clinically or by sequential estimations of serum creatine kinase activity. Large variations in ST segment elevation were found in different patients with a comparable degree of myocardial damage, and at intervals of as little as four hours in the same patient. These variations were greater than could be explained by technical factors, and were not related to apparent changes in the patients' clinical status. The patterns of release of myocardial creatine kinase showed that the time course of ST segment elevation was longer than the period of myocardial necrosis. No correlation was found between the myocardial infarct size as determined by enzyme release and the highest levels of ST segment elevation recorded. The findings suggest that ST segment elevation as measured by praecordial electrocardiographic mapping does not constitute a reliable index of the size or severity of myocardial infarcts in man.


Sinus node dysfunction in acute myocardial infarction. The frequency, clinical course, and prognosis of sinus node dysfunction in 431 patients with acute myocardial infarction admitted to the coronary care unit were studied. Sinus node dysfunction occurred in 20 patients. In 13, the principal manifestation consisted of severe sinus bradycardia. In the remaining 7, periods of bradycardia alternating with episodes of supraventricular tachycardia were noted. Though several of the patients with sinus bradycardia required intravenous atropine or temporary pacing, normal sinus rhythm returned in virtually all during follow-up. The clinical course of patients with both bradycardia and tachycardia was less benign, during the acute phase and during follow-up; 5 of the 6 survivors required continued antiarrhythmic therapy or permanent pacing. The differences in the clinical course between these two groups of patients may reflect distinct underlying pathological changes. The findings in this study suggest that in contrast to sinus bradycardia, the occurrence of bradycardia-tachycardia syndrome during the acute phase of myocardial infarction may have important prognostic implications.


Significance of serum enzyme changes after cardiac catheterization and selective coronary arteriography. The serum creatine kinase (CK), aspartate transaminase (AST), lactic dehydrogenase (LD) and alpha-hydroxybutyric dehydrogenase (HBD) were determined before and 3, 6, 18, and 36 hours after cardiac catheterization and angiocardiography in 56 consecutive patients with ischaemic heart disease. Five of these patients whose serum enzyme levels were higher than normal before the procedure were excluded from the study. Forty-one of the remaining 51 patients had left ventriculography and also selective coronary arteriography. In these 41 patients (groups 1 and 2--see below), the mean serum CK levels increased after the procedure to exceed the upper limit of normal at every study interval. The mean serum AST, LD, and HBD levels generally remained within the normal range at all study intervals, though serum AST increased abnormally in 9 of the 41 patients (22%) and serum LD and HBD each increased above the normal limit in 2 of 41 patients (4.9%). In 24 patients (group 1) whose coronary arteriograms showed insignificant coronary narrowing (less than 75%) in any of the three major coronary arteries, the increase in serum CK was significantly higher than in 17 patients (group 2) with greater than 75% narrowings in at least one of the three major coronary arteries. However, the degree of serum CK elevation observed during the postangiographic period was much lower than that in another group of 30 consecutive patients with acute myocardial infarction. In 10 patients (group 3) who had the same procedure as groups 1 and 2 except without the selective coronary arteriography, the serum enzyme levels showed no noticeable increase after the procedure. The difference in postangiographic serum CK elevation between patients with and without selective coronary arteriography and the difference between group 1 (without significant coronory narrowing) and group 2 (with significant narrowing) strongly suggest that the raised serum CK levels represent some form of myocardial damage caused by the coronary arteriography, which, however, is different at least in degree from that of acute myocardial infarction.


Hepatitis B as a hazard in anaesthetic practice. Hepatitis B is a hazard in anaesthetic practice because the virus is carried in the blood, and operative, investigative or obstetric procedures involve the shedding of blood. A list is given of classes of potential carrier, who should be tested for hepatitis B antigen (HBAg), and a procedure is outlined for minimizing the risk to staff engaged on surgical operations on hepatitis carriers. The carrier state in a patient is not regarded as a contraindication to any necessary operation, nor, in a doctor, to the practice of medicine.


The influence of carboxyhaemoglobin on the oxygen-binding capacity of blood. A comparison of manometric (Van Slyke) and optical (Co-Oximeter) measurements. Oxygen content measurements determined optically by the Co-Oximeter correlated closely with those obtained using the manometric technique of Van Slyke. In those samples with a high content of carbon monoxide, the agreement between the two methods could be improved, by taking into consideration the concentration of carboxyhaemoglobin (COHb), since this plays no part in oxygen transport. The calculated values of the oxygen-binding capacity varied widely, with mean values less than the theoretical figure of 1.39 ml O2/g Hb. This difference was greater in those samples with a higher content of COHb. When the amount of haemoglobin combined with COHb was taken into consideration the mean corrected values approximated to the theoretical value of 1.39, thus supporting this as the mean value for the oxygen-binding capacity of haemoglobin, although the large individual variability persisted.


Long-term assessment of extradural analgesia for the relief of pain in labour. I: Conducting a survey. A method of survey for the long-term assessment of extradural analgesia in labour is described. The difficulties and problems of collecting the data are discussed.


Long-term assessment of extradural analgesia for the relief of pain in labour. II: Sense of "deprivation" after extradural analgesia in labour: relevant or not? Ninety-nine mothers who received extradural analgesia, and 95 who received conventional methods of analgesia for the relief of pain in labour, were interviewed at 18-24 months following delivery. An increase of about 2% in the proportion of mothers experiencing a sense of "deprivation" in the long term in comparison with the findings recorded immediately after delivery was noted. This was not accompanied by the need to seek psychiatric treatment.


Changes in kidney and liver function after methoxyflurane (penthrane) anaesthesia. Three groups of patients receiving methoxyflurane or halothane or pethidine after thiopentone suxamethonium induction were compared. Using multivariate Student t tests with simultaneous confidence intervals, significant differences in the test battery of uric acid, creatinine, blood urea nitrogen and sodium in the methoxyflurane series compared with the other series was found, indicating transient impaired kidney function. Likewise, there was a significant difference between the methoxyflurane and the other series in the s.g.p.t., s.g.o.t., alkaline phosphatase and bilirubin test battery, indicating impaired liver function. This was found after doses less than 16 ml which, so far, had been considered to be without any toxic effects.


Pertinence and precision in pollution measurements. A new approach for the study of the pollution of operating theatre atmospheres by volatile anaesthetic agents is described. Disadvantages of earlier work are discussed together with ways in which they may be overcome. Some pitfalls in analysis, sampling and standardization are indicated and some hazards of incorrect data interpretation are shown. The need for a cautious and critical attitude is emphasized.


The effect of blood flow upon the activity of gallamine triethiodide. The onset, depth and recovery from paralysis produced by gallamine triethiodide were studied using the tibialis anterior muscle/sciatic nerve preparation in mongrel dogs, during changes in blood flow to this muscle. A roller pump was used to effect the blood flow changes via an aorto-femoral shunt. The onset and depth of paralysis were related directly to muscle blood flow. There was no correlation between the rate of recovery from paralysis and the blood flow to the muscle.


Effect of inhalation anaesthetics on division of bone-marrow cells in vitro. The effect of halothane or nitrous oxide or both, on division of cultured, murine bone-marrow cells was investigated. Halothane caused a dose-dependent depression of growth rate ranging from a minimal effect at 0.5% to almost total inhibition at 2.0%. Nitrous oxide 75% had an effect similar to 0.5% halothane and the combination of 0.75% halothane with 75% nitrous oxide produced results little different from 1.0% halothane alone. There was good recovery from 1.0% but not from 2.0% halothane. It is concluded that, in vitro, bone-marrow cells show a similar sensitivity to these agents as was found for other mammalian cell lines which have been investigated. The effect of nitrous oxide was no more than proportional to its narcotic potency relative to halothane.


A manometric study of the upper oesophagus in the dog following cuffed-tube tracheostomy. Intraluminal oesophageal pressures were measured in dogs after tracheostomy and intubation with either uncuffed or cuffed tracheostomy tubes. Possible explanations for disordered swallowing following tracheostomy were found in those animals intubated with cuffed tracheostomy tubes: (a) Increased intraluminal pressures were measured in the oesophagus at the level of the cuffs. (b) Significantly increased pressures were found also 5 and 10 cm below the pharyngo-oesophageal junction. (c) The upper oesophageal sphincter relaxed incompletely.


Spontaneous recovery of the thumb twitch from neuromuscular block by suxamethonium in anaesthetized man. The neuromuscular blocking effect of repeated bolus administration of suxamethonium 1 mg/kg was observed in 10 healthy surgical patients under enflurane-nitrous oxide-oxygen anaesthesia. Tachyphylaxis and slow recovery of the thumb twitch occurred in close dose-relationships with transition of Phase I block to Phase II, using train-of-four fade as an indicator of the transition. Failure of the thumb twitch to recover to 75% of control, and subsequent step-wise depression from additional doses of suxamethonium had a sudden onset shortly after establishment of marked train-of-four fade.


Epidemiology of childhood leukaemia in greater london: A search for evidence of transmission assuming a possibly long latent period. Studies of space-time clustering of cases of childhood leukaemia have yielded equivocal results. This might be because the disease has a long and variable latent period, in which case the usual statistical tests for such clustering are inappropriate. A new statistical method is described which allows for such latent periods. For each patient, periods of "susceptibility" and "infectivity" are defined in which it is assumed he respectively "caught" and could "transmit" the disease. The measure of clustering is taken as the number of patients who were in the "right" place at the "right" time to "catch" the disease from another patient. This test is applied to childhood acute lymphoblastic leukaemia (death before age 6) in Greater London in the period 1952-65. Cases are postulated to be "susceptible" at various times before clinical onset of leukaemia, including in utero, and "infective" at various times around onset. Their effective "contacts" at these times are defined as circles of radius up to 4 km around their places of residence at these times. Slight evidence of clustering was found associated with certain of the defined times and distances, but the degree of clustering was small and could reasonably be attributed to chance. It is suggested, however, that this method of analysis might usefully be applied to other sets of such data. No evidence was found to add to our previously reported finding of space-time clustering of the dates and places of birth of children with leukaemia.


Cell kinetics of urethane-induced murine pulmonary adenomata: II, the growth fraction and cell loss factor. Continuous labelling of urethane induced pulmonary adenomata in adult male A2G mice at intervals up to 20 weeks showed that the growth fraction fell progressively from 18% at 7 weeks to 7% at 20 weeks. This fall appears to be wholly responsible for the decrease in production of adenoma cells with age. A fraction labelled mitoses curve was constructed for pulmonary adenomata at 14 weeks post urethane. Only the first peak was apparent, giving median t2 and ts values of 2 and 9 h respectively. The cell cycle time was calculated at 45 h and the growth fraction at 6-2%, whilst the cell loss factor was estimated at 31%. Other cell loss values were calculated from data on the rate of entry into DNA synthesis obtained previously by double labelling. These values remained constant with time at 83-95%, suggesting that cell loss is in some way linked to cell production. However, the development of polyploidy in adenoma cells could not be eliminated. No areas of necrosis were seen in the adenomata at any time although karyorrhexis occurred in isolated cells. The labelling characteristics of alveolar wall cells in the same lung sections as the adenomata did not vary with time and the continuous labelling curve gave a growth fraction of 1-8%, a DNA synthetic time of 10 h and a cell cycle time of 30 h.


Studies on the stimulation and suppression of deoxyribonucleic acid (DNA) synthesis in lymph node cells of mice bearing progressively growing tumours. Host responsiveness to a progressively growing methylcholanthrene (MC) induced tumour (MC6/2) was studied at varying intervals following subcutaneous (s.c.) tumour implantation by monitoring the in vitro incorporation of tritiated thymidine (3H-TdR) into lymph node cells (LNC) undergoing stimulation in vivo and concurrently determining the total numbers of the lymphoid cells present in these organs at each of the time intervals. It was found that an initial period of rapidly increasing stimulation of DNA synthesis in lymph nodes was soon followed by the onset of a stage of decrease of this activity. Within limits, the larger the tumour inoculum the stronger the initial response. The suppression of stimulation of DNA synthesis that ensued appeared to be directly related to the tumour mass and to the dose of tumour cells implanted. The total numbers of the cells accumulating in nodes also increased initially but remained elevated during the subsequent period of tumour growth. Continued presence of the tumour was essential for the increased DNA synthesis in lymph nodes since tumour removal leads to a rapid decrease to levels found in tumour-free animals. These findings demonstrate that the failure to eradicate an antigenic tumour by its host may not be solely due to "desensitizing" and "blocking" factors but that other important mechanisms are also involved. We suggest that the inability to reject the tumour in this situation is dependent in considerable measure on the development of a state of hyporeactivity in the host due to the partial inhibition of the DNA synthetic response, possibly in T cells of the tumour host, due to "suppressor factor(s)" interacting with the immunocompetent cells.


Studies on the Fc receptor bearing cells in a transplanted methylcholanthrene induced mouse fibrosarcoma. The presence of Fc receptors on the surface of cell suspensions obtained from a transplanted isogeneic methylcholanthrene induced murine fibrosarcoma has been investigated by determining the capacity of such cells to form rosettes with antibody coated SRBC. These studies indicate that a large percentage of cells in the tumour had Fc receptors on their surface. The proportion of such cells was increased by reducing the number of cells transplanted, by administering cyclophosphamide to the host, and on occasions by the i.p. injection of C. parvum. It was largely unaffected by the route of tumour cell transplantation or by T cell depletion of the host before transplantation but appeared to decline in older (i.e. larger) tumours. Both phagocytic and non-phagocytic cells had Fc receptors on their surface. The phagocytic population appeared to be affected most by procedures which altered the overall percentage of Fc receptor bearing cells. The Fc receptor bearing tumour cells were separated from those devoid of Fc receptors on the basis of their adherent properties. Upon transplantation to isogeneic hosts both populations gave rise to tumours containing a high percentage of Fc receptor bearing cells. These studies suggest that many of the Fc receptor bearing cells in our tumour are probably infiltrating cells of host origin. Their significance in relation to tumour growth remains to be established.


Spontaneous shedding and antibody induced modulation of histocompatibility antigens on murine lymphomata: Correlation with metastic capacity. The lability of cell surface histocompatibility antigens of 2 murine lymphomata was examined. These 2 tumours differ greatly in their capacity to metastasize in syngeneic hosts. Cells of the metastatic lymphoma released histocompatibility antigens in vivo and in vitro at a greater rate than cells of the non-metastasizing lymphoma. Antigen/antibody complexes formed by the addition of allo-antiserum to intact cells disappeared more rapidly from the surface of cells of the metastatic line. We propose that the instability of surface antigens may be an integral feature of malignant cells and that there may be a quantitative relationship between the lability of membrane components and the capacity of the tumour to metastasize.


Combined local hyperthermia and x-irradiation in the treatment of metastatic tumours. Six patients, all with evidence of metastatic or locally recurrent tumours, were selected for inclusion in a trial study of simultaneous hyperthermia and ionizing radiation therapy. Heat was applied by hot air, or microwaves, or a combination of both. When examined after treatment, 3 patients were found to be free of the lesions treated. One patient had a partial response, followed by regression of the tumour; one patient died with metastases in the lungs and one patient responded to the treatment but died from a massive pulmonary embolus. The simultaneous application of hyperthermia and ionizing radiation therapy was well tolerated. It induced disappearance of tumours in cases where conventional methods had failed, and with far greater efficiency than conventional therapeutic methods.


An animal model for screening drugs for antipsoriatic properties using hydroxyapatite to isolate DNA rapidly from the epidermis. A new, rapid, simple and accurate procedure for extracting DNA from the epidermis is described involving hydroxyapatite. This compound has an unique property of high affinity for double stranded native DNA, but none for RNA and protein. The technique has been applied to a hairless mouse model for screening systemic and topical agents for cell inhibitory properties in proliferating epidermis for potential use in the therapy of psoriasis. Mitotic counts, autoradiography and a standard chloroform procedure for isolating DNA have confirmed the results obtained using hydroxyapatite column chromatography. In addition, compounds which are known to be effective in psoriasis, have been found to be effective in the system suggesting that it should be a good predictive screen for new therapies. Of several compounds screened for topical activity, cycloheximide has been found to be very effective in the system and preliminary clinical studies confirm its efficacy in psoriasis.


Contact urticaria and anaphylactoid reaction induced by topical application of nitrogen mustard. A 36-year-old woman and a 16-year-old boy, both suffering from mycosis fungoides, developed urticaria and an anaphylactoid reaction after topical whole body application of nitrogen mustard. Prick tests with nitrogen mustard solution produced a weal and flare response. Both patients had previously been treated intermittently with total body application of nitrogen mustard for 2 1/2 years and 1 year respectively without complications.


The repair of impaired epidermal barrier function in rats by the cutaneous application of linoleic acid. Epidermal barrier function in rats was experimentally impaired by two separate means, namely, by rendering the animals deficient in essential fatty acids and by evoking a primary cutaneous irritant response by treating with a solution of sodium laurate. Impaired barrier function was manifested by a greatly increased rate of transepidermal water loss. Application to the skin of sunflower seed oil, which is rich in linoleic acid, rapidly restored to normal the abnormally high rates of transepidermal water loss in both experimental cases, and it was shown with the essential fatty acid-deficient rats that there was a concomitant incorporation of linoleic acid of the sunflower seed oil into epidermal lipids. Cutaneous application of olive oil, which is low in linoleic acid but rich in the non-essential oleic acid, did not influence epidermal barrier function. A close relationship of barrier function and essential fatty acids is indicated.


Elastotic degeneration. A light and electron microscopic study. The formation of elastotic material in the dermis of the exposed skin of elderly persons, and of two younger patients with manifestations of precocious degeneration, was studied by light and by electron microscopy. Initially fine filaments or apparently granular material, or both, appeared around collagen fibres, which were mildly altered. On the exposed sites there was gradual loss of matrix and striation of the collagen forming an amorphous substance in which scattered, optically dense material appeared. Several appearances were common to all subjects.


The ultrastructural changes in the skin in dermatitis herpetiformis after withdrawal of dapsone. The development of skin lesions in patients with dermatitis herpetiformis after the withdrawal of their dapsone therapy was studied with the electron microscope. In control biopsies from patients prior to cessation of treatment,  membrane-bound vacuoles were found beneath the basal lamina of the epidermis as previously described. After dapsone withdrawal, there was an apparent increase in the number of vacuoles and occasionally several vacuoles appeared to have coalesced forming an early blister. At this stage, the basal lamina and associated hemidesmosomes were normal although in places there were small discontinuities in the basal lamina. Where the reaction was more intense, vacuoles and cells, mainly eosinophils, were embedded in fibrin de posits. Above this, the basal lamina was usually disrupted with involvement of the basal epidermal cells. These results suggest that the vacuoles do play a part in the formation of the pathological lesion in dermatitis herpetiformis. In addition, the basal lamina is shown to be only secondarily involved. The nature of the vacuoles has still to be elucidated.


The leukocyte migration inhibition test in allergic nickel contact dermatitis. No statistical difference was found between the migration indices of nickel sensitive and control subjects using the leukocyte migration inhibition test with two concentrations of nickel sulphate. The results contrast with the specific positive results demonstrated previously in the same subjects with the lymphocyte transformation test.


A study on the clinical application of a direct leukocyte migration test in chromium contact allergy. A capillary tube leukocyte migration inhibition assay has been adopted as an in vitro method for the demonstration of chromium hypersensitivity in twenty-two subjects with clinically proven or suspected chromium allergy. Two complexes of trivalent chromium and human serum albumin, exerting different migration inhibitory effects, have been prepared and used as the antigen. In the presence of the chromium-albumin complex with strong inhibitory activity, sensitivity to chromium was demonstrated independent of the clinical condition of the skin in all the patch test positive subjects. An additional positive response to the second chromium-albumin complex was observed only in those patients who were clinically in a state of exacerbation of an allergic contact dermatitis in which chromium allergy was an active causative factor. The results were not influenced by skin allergic reactivity to compounds other than chromium and the method was found to be of practical clinical value for diagnosing chromium allergy.


Hair follicle kinetics in psoriasis.

Hair follicle kinetics in psoriasis. The rate of epidermal cell production has been measured in the various parts of scalp hair follicles in patients with psoriasis of the scalp, and in controls with normal scalp skin. An in vitro technique was used in which thin tissue slices were exposed to tritiated thymidine enabling cells about to divide to become autoradiographically labelled. Biopsies from thirteen patients with psoriasis and nine controls were examined in this way. The labelling indices of the interfollicular epidermis was 27-5% in the psoriatics and 9-5% in the controls. The upper part of the external root sheath had a labelling index of 28% in the psoriatic group compared to 13-9% for the controls. The labelling indices of the sebaceous glands, matrices and external root sheaths were very similar in the two groups. The findings support the hypothesis for a dermal stimulating influence causing the increased epidermopoiesis seen in psoriasis.


An assessment of high and low temperature tars in Psoriasis. Comparison of the efficacy of crude coal tar from high and low temperature sources in the treatment of patients suffering from chronic psoriasis showed the tars to be equally effective. High temperature tar was then compared with standard refined tar. Again, an equal therapeutic response was achieved. Crude coal tars obtained by the carbonization of coal in coke ovens and in smokeless fuel manufacture can be employed in dermatological therapy in place of the dwindling supplies of crude tar of gasworks origin.


Chronic mucocutaneous candidiasis treated with transfer factor. A patient with chronic mucocutaneous candidiasis resistant to all tropical therapy has had extensive tests of immunological function carried out before and after administration of transfer factor. Immunological testing has been both specific, directed at responses to candida antigen, and non-specific, directed at general assessment of the patient's immune status. Transfer factor has been administered on three occasions in the past year. After each treatment temporary clinical improvement accompanied by changes in both specific and non-specific immunological responses have been observed. The possible mode of action of transfer factor in this case is discussed.


Pneumatosis cystoides intestinalis in systemic sclerosis. Pneumatosis cystoides intestinalis (PCI) is a rare condition characterized by the presence of multiple gas containing thin walled cysts in the intestinal wall and mesentery. It is sometimes associated with chronic obstructive pulmonary disease, but has been described most often in patients with gastrointestinal disorders including duodenal and gastric ulceration, small bowel obstruction, regional enteritis and gastrointestinal malignancy. Its association in the patient described below with severe systemic sclerosis is of particular interest. There have been occasional previous reports of this association which should be considered in any patient with systemic sclerosis who develops abdominal symptoms suggestive of acute or sub-acute intestinal obstruction, not readily explicable by other causes.


Postoperative progressive gangrene: a reminder. A classical example of progressive postoperative gangrene is described and the relevant literature has been reviewed. After consideration of the evolution and the clinical appearances of the condition, of the consistency of the associated bacterial flora and of the response to antibiotic therapy alone, we suggest that progressive postoperative gangrene is a distinct entity and separate from pyoderma gangrenosum.


Skin necrosis following warfarin therapy. A typical case of skin necrosis following anticoagulant therapy with warfarin is described.


A comparison of histocompatibility antigens in dermatitis herpetiformis and adult coeliac disease. The incidence of histocompatibility antigens HL-A, 4a and 4b was studied in thirty-eight patients with dermatitis herpetiformis (DH) and thirty-six patients with adult coeliac disease (ACD). The 4b antigen was found in all the DH and ACD patients. HL-A 8 was found in 89% of patients with ACD--similar to the incidence reported in previous studies--and in 79% of patients with DH, a higher incidence than in previous studies which may be due to stricter criteria being used here to diagnose DH. There was no significant difference in the incidence of HL-A 8 between those patients with DH whose small intestinal biopsies appeared macroscopically abnormal and those with a normal macroscopic appearance. These findings suggest that patients with DH form a single disease group and do not support the concept previously postulated that there are two groups of patients with DH, one with an increased incidence of HL-A 8 antigen similar to that in ACD who have a gluten sensitive enteropathy (GSE), and another with a normal incidence of HL-A 8 antigen and without enteropathy.


Histocompatibility antigens and dermatitis herpetiformis with special reference to jejunal abnormalities and acetylator phenotype. Sixty-one patients with dermatitis herpetiformis (DH) were studied. Of these fifty-three (87%) had the histocompatibility (HL-A) antigen HL-A8 as compared with 17% of a control population; the difference is significant. This incidence of HL-A8 among patients with DH is higher than that reported earlier for such patients and is similar to that reported for patients with adult coeliac disease. The incidence of HL-A1 was also significantly greater in the patient group, and was attributed to the increased frequency of haplotype HL-A1, 8. The frequency of HL-A8 was about equal in patients in whom DH was associated with jejunal abnormalities and in those in whom it was not. When correlated with rate of acetylation, there was no significant difference in the occurrence of various HL-A antigens.


Skin lesions in human yersiniosis. A histopathological and immunohistological study. Various types of skin manifestations of human yersiniosis were examined with routine histological and immunohistological methods. The biopsy material consisted of sixteen cases of erythema nodosum, eight cases of erythema multiforme, and one case of erythema figuratum. The principal histopathological changes in erythema nodosum were septal or diffuse, mild panniculitis and in seven cases also necrotizing vasculitis in small, medium-sized or large arteries. Perivascular lymphocytic infiltration without vasculitis was the most prominent feature in erythema figuratum. By using a polyvalent conjugate, immunoglobulins in vessel walls in the dermis were found in two cases of EM. The rapid course of the skin eruptions and the frequency of necrotizing vasculitis in arteries fit the changes seen in an experimental Arthus reaction, in which necrotizing vasculitis is followed by lymphocytic inflammation consistent with a delayed type of reaction.


The inhibiting effect of soft paraffin on the Köbner response in psoriasis. White soft paraffin has been shown to inhibit the development of the isomorphic response (Kobner phenomenon) in psoriasis. The possible reasons for this are discussed and it is suggested that this finding has implications which should lead to a greater understanding of the nature of psoriasis.


Atypical ichthyosiform erythrodernam deafness and keratitis. A report of two cases. Two patients with ichthyosiform erythroderma of the same unusual but characteristic distribution are described. Both patients were born with perceptive deafness and developed severe vascularizing keratitis in early childhood. There is no family history of the disorder in either case. This syndrome is discussed in relation to previous reports of atypical ichthyosiform erythroderma associated with deafness.


Incorporation of I-14C-acetate into the lipids of isolated epidermal cells. Suspensions of epidermal cells were prepared by trypsinization of rat epidermis and incubated with I-14C-acetate in Eagle's minimum essential medium. The incorporation of radioactivity into the total lipids of the cells was increased by the addition of serum to the medium. The pattern of incorporation into the main lipid classes was affected by the addition of serum to the medium and by alterations in the density of the cell suspensions. The incorporation of radioactivity into the total lipids increased approximately linearly over a 24-h period of incubation and the pattern of incorporation into the phospholipids and glycolipids altered with time. However, at each time interval studied, reporducible patterns of incorporation were obtained under controlled conditions. The incorporation of radioactive acetate therefore provides the basis for a very sensitive method of lipid analysis.


The relationship between the course of psoriasis and transepidermal water loss, photoelectric plethysmography and reflex photometry. The transepidermal water loss (TWL), photoelectric plethysmography and reflex photometry were parallelly registered on the involved hands and forearms of psoriatics. The TWL values showed a fairly good correlation with the clinical course of the disease: they increased during the active phase and decreased after return to normal. The vascular tests did not show a strict parallelism with the clinical state. On the basis of the findings, the temporal relations between epidermal and vascular factors during the different phases of the psoriatic process are discussed. The TWL can be used to predict a relapse occurring on the area investigated but not on a distant area.


Prostaglandins and pruritus.

Prostaglandins and pruritus. We have found that pretreatment of human skin with prostaglandin E1 significantly lowers the threshold of human skin to itching evoked by both histamine and papain. Prostaglandins may thus potentiate pruritus in inflammatory skin disease, presumably by a non-specific effect on nerve-endings.


The adenosine triphosphate content and lactic acid production of guinea-pig skin after mild heat damage. The depletion of adenosine triphosphate in skin after mild thermal injury is not large enough to be accounted for by loss of oxidative respiration. Measurement of lactic acid production by skin suggest that glycolysis is less sensitive to heat damage than is oxygen uptake. It is therefore likely that glycolysis makes a large contribution to the relatively high levels of ATP persisting in heat damaged skin.


Enzyme activity in human scars, hypertrophic scars and keloids. Biopsies from non-hypertrophic and hypertrophic scars and from normal skin have been studied histochemically for activities of nicotanamide adenine dinucleotide diaphorase, lactate dehydrogenase, acid phosphatase, beta-D glucuronidase and alkaline phosphatase. The activities of all enzymes studied except alkaline phosphatase were found to be increased in hypertrophic scars as compared with non-hypertrophic scars and normal skin.


Pathogenesis associated with hair follicle mites (Demodex spp.) in Australian Aborigines. Demodex folliculorum and D. brevis are found in different habitats in the skin: the former in the hair follicles, the latter in the sebaceous glands. Both seem minor pathogens--merely harvesting the cells of their respective habitats. D. folliculorum was found aggregated (all stages) and plugging the follicular orifices; D. brevis, on the other hand, was usually solitary. In one case marked degeneration of the sebaceous gland, with leukocyte invasion, was associated with D. brevis. No correlations were discovered between either of these species and the gross condition of the skin. Positive samples were obtained from both mainland and island populationf of Aborigines. Incidence values obtained were 66.6% for males and 80% for females; in the latter, the sample was small (5) and their ages over 34 years.


Inhibition of membrane peroxidation in thalassaemic erythrocytes by 2,3-dihydroxybenzoic acid. Both iron and precipitated haemoglobin may catalyse the formation of free radicals, which in turn react with the polyunsaturated fatty acids of membranes leading to membrane failure and cell death. 2,3-Dihydroxybenzoic acid (2,3-DHB), a recently identified, orally effective iron-chelating drug, inhibited membrane peroxidation in vitro in H2O2-stressed erythrocytes from patients with beta-thalassaemia major, beta-thalassaemia intermedia, haemoglobin Köln disease and sickle cell disease. We present evidence suggesting that the inhibition of peroxidation is due to ability of 2,3-DHB to scavenge free radicals via quinone formation, a mechanism analogous to that proposed for vitamin E.


Variations in globin chain synthesis in hereditary persistence of fetal haemoglobin. Globin synthesis was studied in four Negro families including 10 members with Hb A-HPFH and four with Hb S-HPFH. The beta/alpha specific activity ratios in 10 of these HPFH heterozygotes were similar to those of the control group. In two patients with Hb A-HPFH, the beta/alpha ratio was slightly decreased in one (0.84) and clearly decreased in another (0.78). In two of the patients with Hb S-HPFH the ratios were clearly decreased (0.71 and 0.75). The extended range of beta/alpha ratios in these 14 patients is similar to that of Negro patients with beta-thalassaemia trait. These studies indicate that a decreased beta/alpha ratio may be found in HPFH, as well as in beta-thalassaemia. Bone marrow globin synthesis was measured in two patients with Hb S-HPFH and decreased peripheral blood beta/alpha ratios, and in one with Hb A-HPFH and a normal peripheral blood beta/alpha ratio. In each patient the (beta+gamma)/alpha ratio of radioactivities as well as the beta/alpha specific activity ratio was close to 1 and therefore balanced, indicating more rapid decay of beta-chain synthesis relative to alpha-chain during red cell maturation or extremely rapid destruction of newly synthesized excess alpha-chains in the bone marrow.


betaS Chain turnover in reticulocytes of sickle trait individuals with high or low concentrations of haemoglobin S. Reticulocytes, isolated from the blood of sickle cell trait donors with either low (25-30%) or high (40-42%) haemoglobin S(Hb S) concentrations, were incubated with [3H]leucine for various times from 1.25 to 60 min. Samples of the total soluble fractions of the cells were denatured with urea and mercaptoethanol. The mixtures were analysed by electrophoresis on cellulose acetate strips. The specific radioactivities (dpm/mg) of the separated betaS and betaA globin chains were determined. The betaS/betaA ratios of globin chain specific radio activities in the reticulocytes of the 'low Hb S' donors decreased gradually from initial values higher than 1.30 to values near unity. These data suggested that faster turnover of some of the soluble, newly synthesized betaS chains compared to the newly synthesized betaA chains could explain part, but not all, of the disparity in concentrations of Hbs S and A in these people. When reticulocytes from 'high Hb S' donors were 3H-labelled for times longer than 5 min, the betaS/betaA specific radioactivity ratios remained at or near unity. This result suggested that newly synthesized betaS chains were not turning over selectively in these cells. Instead, there was a relative decrease in betaS chain synthesis proportional to the difference in blood concentrations of Hb S and Hb A. Additional calculations suggested that the more rapid turnover of newly synthesized betaS chains in the 'low Hb S' reticulocytes could explain the difference in Hb S concentrations between 'high and low Hb S' people. These results are consistent with previous reports that an alpha-thalassaemia gene, present in 'low Hb S' but absent in 'high Hb S' donors, may be responsible for the selective turnover of betaS chains.


Effects of sulphydryl compounds on abnormal red cell pyruvate kinase. The effect of some sulphydryl compounds on two new variants of red cell pyruvate kinase (ATP: pyruvate phosphotransferase, PK) is reported. In vitro a striking correction has been obtained of both the qualitative and, in one case, the quantitative defect of red cell PK. In vivo, a correction of the qualitative and quantitative abnormalities has been produced in both patients, with clinical improvement of one of them. These findings, together with the unexpected results in respect to the functional properties of PK found in the affected members of the two families studied, suggest that the PK abnormality is not the cause of the haemolytic anaemia, but an epiphenomenon of a primary unknown defect that apparently involves the red cell thiol groups.


Variable response of bone marrow to feeding DL-5-formyltetrahydrofolate in pernicious anaemia. It has been suggested that the megaloblastic anaemia in pernicious anaemia is due to inadequate intracellular concentration of monoglutamyl folates other than methyltetrahydrofolate caused by diminished conversion of methyltetrahydrofolate to tetrahydrofolate (methylfolate trap). To test this, we have increased the concentration of methyltetrahydrofolate in the plasma of six patients with pernicious anaemia by feeding DL-5-formyltetrahydrofolate. The effect of therapy on bone marrow morphology and routine haematologic parameters was measured. Of two patients receiving 800 mug/d of DL-5-formyltetrahydrofolate, one had a significant response; of four receiving 6 mg/d, one converted erythroid maturation to normoblastic, and in two others some improvement was noted in levels of neutrophils, platelets or reticulocytes although marrow morphology remained megaloblastic. Response did not correlate with the degree of elevation of plasma folate. In patients receiving this therapy, slight increase of methylcobalamin in plasma may have occurred (P less than 0.05). These observations support ineffective utilization of methyltetrahydrofolate as the major cause of megaloblastic anaemia in pernicious anaemia, but indicate that the degree and location of block varied in different patients, and in different precursor cells of a single patient.


Measurement of the mean cell volume using electronic particle counters. Under carefully controlled conditions electronic cell counters, for example the Coulter Counter, Model FN, and Channelyzer, may be calibrated to give MCV values down to as small as 20 fl which agree with those derived from the centrifugation PCV (corrected for plasma trapping) and the red cell count. The MCV values will be too high if the instrument uses a high cell concentration, has a fixed lower threshold, no effective upper threshold and no edit facility. This may partly explain why the Coulter Counter, Model S, when standardized with 4C cell control gives higher MCV values than the Model FN linked to the Channelyzer. The difference is, on average, 2 fl with normal blood samples and 5 fl in cases of microcytic anaemia. It is suggested that standards of low MCV should be used together with those of normal MCV when calibrating the Model S.


Sodium pertechnetate as a red cell label: in vitro and in vivo studies. In vitro investigations were performed to re-examine the variables that influence the binding of sodium 99TCm-pertechnetate to human red blood cells. Irreversible binding of the radioisotope was observed only when red cells were incubated with tin chloride after their incubation with pertechnetate; binding of pertechnetate is completed within 10 min after its addition to red cells. Composition, temperature and possibly the oxygen saturation of the incubation medium affect the fraction of the isotope that becomes red cell-bound. Using a labelling method derived from these in vitro studies, the usefulness of pertechnetate-labelled autologous red cells for the determination of red cell volumes was studied. Elution of pertechnetate occurred in vivo in an exponential fashion. Using the specific red cell activity, corrected for elution, of blood samples drawn 30 min after injection of 99Tcm-labelled red cells, calculated red cell volumes were almost identical to those determined simultaneously with radiochromate-labelled cells. It is concluded that 99Tcm-pertechnetate is a useful label for red cell volume determination; it may be less reliable when delayed mixing of the labelled red cell tracer in the patient's circulation is expected.


Leucocyte function in a case of chronic benign neutropenia of infancy associated with circulating leucoagglutinins. A case of chronic benign neutropenia is described in association with circulating leucoagglutinins. IgG and IgM leucoagglutinins demonstrated by Sephadex G-200 chromatography agglutinated neutrophils and monocyte enriched leucocyte preparations. Total IgG, IgA, IgM and IgE, total haemolytic complement, C3 and C4 complement components were all within normal limits. Lymphocyte populations and transformation were normal apart from a relative increase in the number of B lymphocytes. In vitro studies showed that the patient's monocytes responded in chemotaxis, phagocytosis and intracellular killing of S. aureus in a comparable fashion to that of control neutrophils. Although the patient's serum also agglutinated monocytes these findings do not exclude the possibility that leucoagglutinins may have aetiological significance in this disease. The study also emphasizes the versatility of the monocyte in benign neutropenia.


The function of the anterior pituitary-adrenal cortex axis in hyperemesis gravidarum. In order to study the function of the pituitary-adrenal axis, serum ACTH and cortisol levels were estimated before and after insulin induced hypoglycaemia in nine women with hyperemesis gravidarum, seven women in normal early pregnancy and in eight non-pregnant controls. Before hypoglycaemia, the basal ACTH level in the hyperemesis group (102-4+/-62-9 pg/ml) was higher than in normal early pregnancy (67-5+/-19-2 pg/ml; p less than 0-05) or in non-pregnant controls (54-8+/-25-2 pg/ml; less than 0-01). Correspondingly, the mean cortisol value in hyperemesis (0-47+/-0-16 mumol/l) was higher than in normal early pregnancy (0-39+/-0-10 mumol/l; p greater than 0-05) or in non-pregnant controls (0-32+/-0-13 mumol/l; p less than 0-01). After insulin the elevation of ACTH (p greater than 0-05) and cortisol (p less than 0-01) was observed in every group. The level of ACTH and cortisol was highest in hyperemesis group. Our results do not support the idea that hypofunction of the pituitary-adrenal axis contributes to the aetiology or pathogenesis of hyperemesis gravidarum. The high ACTH level might be evidence of the psychia instability of hyperemesis gravidarum patients.


Extradural analgesia in labour when the breech presents. A retrospective study was made of the course and outcome of labour in 226 patients in whom a singleton fetus presented by the breech. Patients with macerated stillbirths or who were delivered before the 28th week of gestation had been excluded. Of the 226 patients, 101 received extradural analgesia, 79 received parenteral analgesia and 46 underwent elective Caesarean section. There was no difference in the incidence of breech extraction or emergency Caesarean section in the first two groups of patients. The length of both first and second stages of labour in multiparae was prolonged in the extradural group, but not markedly so. The Apgar scores of the infants delivered vaginally were not significantly different at one minute in both groups but the five minute Apgar score in the infants of primiparae was significantly higher in the extradural group. The Apgar score at one minute in the group delivered by emergency Caesarean section was significantly lower after extradural block but the difference was not significant at five minutes. This study suggests that the management and outcome of labour when the breech presents is not adversely affected by the provision of extradural analgesia.


Plasma gonadotrophin levels in ovulatory and anovulatory patients. Although episodes of FSH values were similar in subjects with secondary amenorrhoea and oligomenorrhoea, but patients with oligomenorrhoea had significantly higher plasma LH secretion in four normal, fourteen anovulatory and one postmenopausal woman were confirmed by samples taken every 15 minutes for three hours, single plasma samples invariably provided a valid estimate of the current mean plasma FSH level, and of the current mean plasma LH level during the follicular phase of the ovulatory menstrual cycle and in anovulatory women with a mean plasma LH value of less than 0-8 mIU/ml. If the mean plasma LH value in anovulatory women exceeded 0-8 mIU/ml, the maximum difference between single and mean values was 28-3+/-4-7 per cent for four patients with oligomenorrhoea and 43-4+/-5-2 per cent for five patients with secondary amenorrhoea. Single plasma samples were collected from 26 patients with primary amenorrhoea, 95 patients with secondary amenorrhoea, 51 patients with oligomenorrhoea and 33 postmenopausal patients not on replacement therapy. In each group there were subjects with plasma FSH values in the postmenopausal range and they were unlikely to respond to ovulation induction. Those patients aside, plasma FSH values were similar in subjects with secondary amenorrhoea and oligomenorrhoea, but patients with oligomenorrhoea had significantly higher plasma LH values (p less than 0-001); mean levels of neither FSH nor LH showed a significant correlation with response to treatment with clomiphene but in patients with secondary amenorrhoea an ovulatory response to clomiphene did not occur unless the individual's plasma FSH value was in excess of 1-4 mIU/ml. In patients with oligomenorrhoea, plasma LH levels below 0-8 mIU/ml precluded successful treatment with clomiphene.


Dydrogesterone and endometriosis.

Dydrogesterone and endometriosis. The results are reported of the administration of dydrogesterone, 5 mg twice daily, to 49 patients with endometriosis. All but five patients were symptom-free after nine months of therapy. Most subjective symptoms had disappeared within four to eight weeks; dyspareunia usually took longer. In 30 out of 32 patients who had a culdoscopy after one or two treatment courses, a 'cure' of endometriosis was confirmed. Ten out of nineteen infertile patients became pregnant following treatment. The only side-effects were transient mastalgia and dizziness in two patients. No amenorrhoea or other disturbances of the menstrual cycle were reported.


Hydatidiform mole and thyrotoxicosis. A case report. A case is reported of coexistent hydatidiform mole and thyrotoxicosis. The latter was treated medically prior to evacuation of the mole, thereafter thyroid function returned to normal.


Advanced abdominal pregnancy with severe pre-eclampsia. Severe pre-eclampsia leading to fetal death in advanced abdominal pregnancy is reported. Attention is drawn to the low reported incidence of pre-eclampsia in this condition and possible explanations are put forward.


Colposcopic evaluation of patients with abnormal cervical cytology. Because of suspicious or abnormal smears, 620 patients were referred to the Colposcopy Clinic of the British Columbia Cancer Institute between 1st March 1973 and 31st December 1974; it was possible to make a colposcopic examination in 549 of these patients (88.5 per cent). The colposcopic impression was within one histological grade of a colposcopically-directed biopsy in 476 patients (86 per cent). There were 221 patients who had a cone biopsy after a colposcopically-directed biopsy and in 192 of these (87 per cent) the two biopsies were within one histological grade of each other; but there were two patients with occult invasive carcinoma in a cone biopsy and only carcinoma in situ in a directed biopsy. In the same group of 221 patients the colposcopic evaluation and final diagnosis (the most advanced histological lesion seen in biopsy) agreed in all but seven patients.


The importance of flexion in vacuum extractor delivery. Two modifications of Malmstrom's cup were used in a study of the position of the cup in 500 vacuum extractor deliveries. The incidence of completely flexing applications varied from 0 to 92 per cent according to the level of the head and the position of the occiput when the cup was applied and, in occipito-posterior positions, the type of cup that was used. With mid-cavity occipito-posterior positions it was 30 per cent with one modification (suction tube attached eccentrically to the dome of the cup--the "modified" cup) and 92 per cent with the other (tube attached to the lateral wall of the cup--the "occipito-posterior cup" or "OP cup"). The high incidence of face-to-pubis or occipitio-lateral delivery when cups with a dome-attached suction tube were used in mid-cavity occipito-posterior positions was found to be largely the result of deflexing applications. It was concluded that cups of this type are unsuitable for use in these cases. A study of two large series of vacuum extractor operations suggested that failed vacuum extractor rates can be reduced by using cups that are manoeuvreable and which accept stronger oblique traction than Malmstrom's cup.


Hyperextension of the fetal head in breech presentation: radiological evaluation and significance. Damage of the cervical cord is not rare in breech delivery with hyperextension of the fetal head. Among 57 cases from the literature and one of ours in which the angle of extension could be measured on X-ray films, 20 had an extension angle greater than 90 degrees. Of these, 11 were delivered vaginally and included 8 cases of damage to the cervical cord. It is recommended that elective Caesarean section be performed when the angle of extension exceeds 90 degrees.


A study of the elasticity and tension of fetal membranes and of the relation of the area of the gestational sac to the area of the uterine cavity. The surface area of the uterine cavity before delivery was compared with that of the gestational sac after delivery and experiments were carried out to test the elasticity of membranes and the tension on them during labour. The results indicated that after 28 weeks of pregnancy the intact fetal membranes were under tension and were not a passive lining to the uterine cavity and that there was a significant decrease in the elasticity of those membranes which ruptured before labour irrespective of the maturity of the pregnancy. The results failed to support the suggestion that there was a deficiency in the area of the gestational sac in those cases where the membranes ruptured before labour.


Experiments in the measurement of intrauterine pressure. A series of experiments investigating the quality of the signals obtained from intrauterine catheters was conducted in the labour rooms and laboratories. Clear evidence of signal attenuation due to partial blockage of catheters was obtained. Some methods which might help to overcome these problems are discribed.


Investigation of some problems associated with the Cardiff infusion pump. Since there is some concern about the use of the Cardiff infusion pump in the automatic mode, experiments were devised to simulate some possible problems. The possibility of misleading information allowing overstimulation to occur was demonstrated. Even when the input signal was accurate there could, at least theoretically, be excessive stimulation. Some suggestions about future design and ways of correcting the problems are discussed.


Plasma oestriol and human placental lactogen measurements in patients with high risk pregnancies. Maternal plasma oestriol and human placental lactogen (HPL) were measured serially in 383 at-risk pregnancies. Eight-five infants were growth retarded and 122 developed fetal distress or neonatal asphyxia. Of the infants whose mothers had either abnormal plasma oestriol or HPL levels, 58 per cent were growth retarded, while 65 and 73 per cent in each group respectively developed fetal distress. The incidence of fetal complications when both plasma oestriol and HPL were abnormal was consistently greater than 66 per cent.


Serum cystine aminopeptidase and the small-for-dates baby in hypertensive pregnancy. Serum cystine aminopeptidase levels and gradients have been assessed retrospectively in hypertensive mothers delivering small-for-dates babies, compared with those delivering normal weight babies. The average accuracy of predicting the weight range of the infant (normal or small-for-dates) would have been about 82 per cent.


Effect of insulin on adipose tissue lipolysis in human pregnancy. Adipose tissue has been shown to retain its sensitivity to the antilipolytic effects of insulin during late pregnancy. This suggests that during late pregnancy, increased adipose tissue lipolysis is due to a lipolytic factor rather than insulin resistance.


Changes in lymphocyte function during pregnancy. A gradual increase in spontaneous lymphocyte DNA synthesis was demonstrated in each trimester of pregnancy. Autoradiographic studies indicated that lymphocytes were primarily responsible for this activity. PHA-induced lymphocyte transformation in both fetal calf serum and autologous serum was significantly reduced in the second and third trimesters of pregnancy. Spontaneous lymphocyte DNA synthesis was significantly reduced in patients with mild pre-eclampsia. However, no significant differences were seen in patients with severe pre-eclampsia in the third trimester of pregnancy compared with the normal control subjects. No evidence was adduced to implicate inhibitory humoral factors affecting the peripheral blood lymphocytes in pregnany patients in experiments in which washed lymphocytes were cultured in medium containing heterologous serum. In vitro experiments demonstrated that cortisol, progesterone and HPL caused a significant reduction in lymphocyte DNA synthesis, and HGH and HCG had a variable effect. However, only cortisol was regularly inhibitory at physiological concentrations. The progesterone effect was dose-related, producing 90 per cent inhibition of activity at a concentration of 10 mug/ml. No synergism could be shown between HPL and progesterone on lymphocyte transformation. The increase in activity of circulating immunoreactive cells during pregnancy and its depression with the onset of pre-eclampsia is discussed.


Extra-amniotic pregnancy. A case report. A case of extra-amniotic pregnancy ending in premature labour at 35 weeks is reported.


Endogenous nitrogen excretion and utilization of dietary protein. 1. The endogenous nitrogen losses of men of different ethnic, ecological and socio-economic backgrounds are similar when calculated per unit body-weight or per unit basal energy consumption. The hypothesis that endogenous N losses, adjusted upwards by a factor of 0-30 to equate them with N equilibrium, can be used to derive man's physiological requirements for proteins of high quality, e.g. those of egg and milk, was studied. 2. Men living in Nigeria, accustomed to eat diets which provided mixtures of protein only slightly higher than the 'safe level of intake' proposed by the Joint FAO/WHO ad hoc Expert Committee on Energy and Protein Requirements (FAO/WHO, 1973), were found to use absorbed N more efficiently than University of California students who habitually consume diets which supply a great excess of protein over that 'safe level'. 3. The greater protein-sparing effect of carbohydrates than of fats and oils may play a part in this more efficient use of protein by men living in developing countries. Also, man possesses mechanisms in intermediary metabolism which allow him to adjust to low levels of protein intake. 4. Thus it appears that all apparently healthy men cannot be considered equal in regard to their requirements for protein.


The effect of sodium chloride ingestion on food intake and on fat deposition in male rats. 1. A 21 d slaughter trial was done using weanling male rats offered sodium chloride added at 10, 20 and 30 g/kg to a nutritionally adequate, control diet containing 13 g NaCl/kg, or added to the drinking-water at 5, 10 or 15 g NaCl/l. Food and drinking-water with or without NaCl were offered ad lib. and their intakes were measured. 2. NaCl in the food reduced food intake by 10-15%; NaCl in solution reduced food intake only when added at the 15 g/l level; the reduction was 25%. 3. NaCl increased the fluid intake of the rats; for NaCl in the food the increments ranged from 23 to 44%; for NaCl in the drinking-water they ranged from 44 to 229%. 4. Body fat was significantly reduced by 20 and 30 g NaCl/kg added to the control diet, indicating a reduction in the efficiency of fat synthesis. Comparable amounts of NaCl taken in the drinking-water had a negligible effect on fat deposition. 5. It is suggested that NaCl in the food produces hypodipsia, i.e. a failure to drink an optimal amount of water, causing changes in the electrolyte balance which reduce food intake and progressively reduce the efficiency of fat synthesis.


Net utilization of roughage and concentrate diets by sheep. 1. Two diets, an all-roughage diet and a high-concentrate diet, were fed at two levels, a low level of estimated 1-5 times maintenance energy requirement and a higher level of estimated two times maintenance energy requirement, to South African Mutton Merino castrated male sheep, aged 13 months and in fairly lean condition at the start of the 93 d experimental period. 2. Body composition and energy retention were determined using the comparative slaughter technique and two series of digestibility and balance studies were done during the course of the experiment. Metabolizability of each diet was estimated and corrected for fermentation heat using the fermentation balance approach. 3. Although there were significantly different rates of energy gain on different diets and feeding levels, fat energy gained (% total energy gained) was similar for the four groups, i.e. 78-80. 4. Regression of energy gain v. corrected metabolizable energy (ME) intake indicated that the maintenance energy requirements of sheep used in this experiment were 310-2 and 302-3 kJ ME/kg body-weight0-75 per d and the values for net utilization of ME for body energy gain were 0-411 and 0-479 with the roughage and concentrate diets respectively. 5. It was concluded that the estimated maintenance energy requirements of sheep obtained in this study are realistic values and that the efficiency of utilization of surplus ME for the two diets did not differ significantly.


Screening for risks of cardiovascular disease in children. A preliminary report. 1. The results obtained for 236 Viennese schoolchildren between 11 and 12 years of age indicated that 38% of children had an increased concentration of cholesterol in their serum and 3% had an increased serum triglyceride concentration. 2. The results of the preliminary study suggested that, by extending the dimensions of the screening, further problems, for example the correlation between different 'risk' factors and the significance of nutritional habits, might be studied.


Food intake and energy expenditure of Indian troops in training. 1. Food intake and energy expenditure were determined on 500 soldiers drawn from infantry, artillery and engineer units of the Indian army, for 3 months during winter. 2. The units were located in two different regions of India at altitudes varying from sea level to 2300 m. 3. The energy requirements were assessed from the actual food intake as well as from energy expenditure and from the changes in body-weight and skinfold thickness. 4. The nutritional adequacy of the diet was assessed from clinical examination and changes in blood haemoglobin concentration. 5. The mean energy expenditure was found to be 15-39 MJ (3679 kcal) and on this basis the energy requirements was 16-61 MJ (3970 kcal); energy intake was found to be 16-47 MJ (3936 kcal). 6. The energy contributed by protein, fat and carbohydrate was 0-115, 0-240 and 0-645 of the total intake respectively. 7. There was no significant change in body-weight, blood haemoglobin level and skinfold thickness on this mean daily intake.


The relationship between the zinc status of pigs and the occurrence of copper- and Zn-binding proteins in liver. 1. A study has been made by gel filtration techniques of the soluble copper- and zinc-binding proteins in livers from pigs of different Zn status. 2. The distribution of both Cu and Zn between the three fractions isolated was greatly influenced by the Zn status of the animal. In livers from pigs given a Zn-supplemented diet the proportion of either Cu or Zn found in the fraction with a molecular weight of about 12 000 (fraction 3) was a direct function of the total liver concentration of the metal. In livers from pigs given a low-Zn diet, only small amounts of Cu or Zn were present in this fraction, regardless of liver Cu content. 3. These results suggest that Zn may be essential for the stabilization of the metal-binding protein in this fraction.


Enzymic evaluation of thiamin, riboflavin and pyridoxine status of parturient women and their newborn infants. 1. Thiamin, riboflavin and pyridoxine status of 'low-income-group' mothers and their newborn infants was assessed by analysing paired samples of maternal and umbilical cord blood for erythrocyte transketolase (EC 2.2.1.1) (ETK), erythrocyte glutathione reductase (EC 1.6.4.2) (EGR), and erythrocyte aspartate aminotransferase (EC 2.6.1.1) (EAA) activities. 2. The vitamin status of the infants was better than that of the mothers. 3. Most of the mothers and some of the infants had biochemical evidence of thiamin and riboflavin deficiency. 4. The pregnant women had a higher EAA activity and also higher stimulation with pyridoxal-5-phosphate than the non-pregnant women of the same community. 5. There was a significant correlation between maternal and umbilical blood samples for ETK and EGR activities, but not for EAA activity or any of the coenzyme stimulation tests.


The effect of methods of sterilization on the nutritive value of protein in a commercial rat diet. 1. The effect on protein quality of treating a commercial rat diet by autoclaving at various temperatures for different periods of time, or by irradiation with 2-5 or 10 Mrd, was studied. True digestibility (TD) and biological value (BV) were measured and the available and total amino acids in the diets were estimated using microbiological and chemical methods. 2. Autoclaving at 121 degrees for 60 min reduced BV, TD and net protein utilization (NPU) more than autoclaving at 134 degrees for 3 min. Availability of amino acids was reduced by both treatments but to a greater extent by autoclaving at 121 degrees for 60 min. Total amino acids were essentially unaffected. Irradiation had no effect on BV, TD, NPU or total amino acids, and the availability of amino acids was also unaffected, with the exception of lysine which was slightly reduced. 3. When the diet was autoclaved at 115 or 121 degrees for 15, 30 or 60 min, or at 134 degrees for 3 min the availability of the amino acids was reduced with increasing time and temperature of treatment. Treatment at 134 degrees for 3 min had an effect on available amino acids similar to treatment at 121 degrees for 15 or 30 min. 4. Ethylene oxide fumigation of the diet caused reduced availability of histidine, methionine and tryptophan but had negligble effect on arginine, leucine and lysine. 5. It is concluded that from a practical point of view irradiation causes least damage to proteins in rodent diets. If such diets are to be autoclaved they should be supplemented with complete protein to counteract amino acid destruction.


Excessive vitamin D content of a standard iron-deficient diet for rats. 1. The observation that thyroid C cell hyperplasia occurred in rats given the iron-deficient diet described by McCall, Newman, O'Brien, Valberg & Witts (1962) prompted a closer study of the preparation and constituents of this diet. 2. It became apparent that there was a discrepancy between the amounts of fat-soluble vitamins in the dietary formulation reported and the supposed final content of the diet. A diet prepared as described by McCall et al. (1962) contains 1000 mug (40 000 i.u.) ergocalciferol and 10 mug (14 500 i.u.) retinyl palmitate/kg. 3. An experiment was designed to study the effect of Fe-deficient and Fe-supplemented, high-vitamin-D diets, and an Fe-supplemented, normal-vitamin-D diet, on thyroid C cell volume and serum calcium concentration. 4. Thyroid C cell volumes and serum Ca concentrations were significantly higher in both groups given excess vitamin D than in the group given the Fe-supplemented, normal-vitamin-D diet. It is evident therefore, that hypervitaminosis D was the cause of the morphological and biochemical changes found in rats given the McCall et al. (1962) diet.


Thermic effect of glucose in obese subjects studied by direct and indirect calorimetry. 1. The thermic effect of a glucose load (50 g) was studied in ten control and eleven obese female subjects, using both direct and indirect calorimetry simultaneously. Experiments were done under conditions of thermal equilbrium (28 degrees and 30% relative humidity). 2. Thermal balance (heat production measured by indirect calorimetry minus heat losses measured directly) was negative in the control group during the fasting period (heat deficit -14-2 +/- 5-0 kJ/m2 per h), whereas that of the obese group was in equilibrium (+ 1-4 +/- 4-8 kJ/m2 per h). 3. After the glucose load, metabolic rate increased 13-0 +/- 1-5 and 1-3% in the control and obese groups respectively. 4. In contrast to the metabolic rate, total heat losses were not significantly altered in either group after the glucose load. Total heat losses of the obese group were significantly lower than those of the control group throughout the experimental period. 5. During the experiments the amount of heat stored was increased in both groups. Thermal balance in the control group became positive while that of the obese group remained positive. 6. During the fasting period, the control subjects oxidized more carbohydrates (90-4 mg/min) than lipids (68-8 mg/min), whereas obese subjects oxidized more lipids (103-7 mg/min) than carbohydrates (50.2 mg/min). After the glucose load, the oxidation rate of carbohydrates was increased in both groups to 158-1 mg/min in control subjects and 95-6 mg/min in obese subjects. 7. The mean skin temperature of the control subjects was significantly higher than that of the obese subjects and remained higher throughout the postprandial period. 8. These results indicate that: (a) during the fasting period, the energy sources utilized and the thermal balance of the two groups were different; (b) the thermic effect of glucose was less in the obese subjects and, therefore, might be a factor contributing to their low energy expenditure.


Alpha-S-cysteinylthymine: a model for protein-nucleic acid cross-linking. Crystals of alpha-S-cysteinylthymine, C8H12CIN3O4S, formula weight 281.72, are orthorhombic, space group P212121, with a=9.499 (1), b=24.072 (4), and c=5.012 (1) A, V=1146.1 (2) A3, and Z=4. The structure was determined by the direct method and refined by a full-matrix least-squares procedure to a final residual, R=0.043, using 1277 diffractometer data. From the structure, a three-dimensional model for the radiation-induced interaction of thymine residues and cysteine residues could be postulated.


Chromatin models. The ionic strength dependence of model histone-DNA interactions: circular dichroism studies of lysine-leucine polypeptide-DNA complexes. The ionic strength dependence of the complexes between DNA and both random, (Lysx, Leuy)n, and block copolymers, (Lysx)n(Leuy)m, of lysine and leucine, with different amino acid compositions, was studied using circular dichroism (CD) as the probe to detect conformational differences in these complexes relative to native DNA. It was found that the CD spectra of complexes of both the random (Lys84, Leu16)n and block (Lys85)n(Leu15)m copolymers with DNA show a very sharp ionic strength dependence. The maximum altered CD spectrum for the complexes with the block copolymer was found to occur at the same ionic strength as that for poly(L-lysine)-DNA complexes, while the maximum CD change for the random copolymer complex occurred at a slightly lower ionic strength. This sharp dependence of the CD change on the ionic strength was found to be independent of the polymer/DNA ratio, r, for each individual copolymer. The CD spectra for these complexes at optimum NaCl concentration resemble those of the psi spectra of DNA [Jordan, C. F., Lerman, L.S., and Venable, J.H. (1972), Nature (London), New Biol. 236, 67]. The complexes of the random copolymer, (Lys68, Leu32)n, with DNA (r=0.25) at 0.15 M NaCl and below have CD spectra that resemble the A-form DNA spectra. The ionic strength dependence of the CD spectra of this complex is not as sharp as observed with the above polymers and has a broad positive plateau. It is suggested that both the CD spectra of these complexes reflect the phenomena of DNA condensation into a higher order asymmetric structure (folded and compact). The block copolymer, (Lys77)n(Leu23)m, complexes with DNA show very slight alterations in the CD spectra, with respect to native DNA. It appears that the long Leu sequence at one end of such copolymers may be unpropitious for causing the polypeptide-DNA complex to condense into a higher order asymmetric structure. Thus the importance of the distribution of hydrophobic residues, in the copolypeptides of Lys, is shown for causing condensation of complexes with DNA. The relevance of these findings to histone-DNA complexes in chromatin is discussed.


Chromatin models. Thermal denaturation studies of (Lysx, Leuy)n-and (Lys)n(Leu)m-DNA complexes. The structural transitions of (Lysx, Leuy)n-DNA and (Lysx)n(Leuy)m-DNA complexes have been studied by thermal denaturation utilizing simultaneous absorption and circular dichroism (CD) measurements [R. Mandel and G.D. Fasman (1974), Biochem. Biophys. Res. Commun. 59, 672]. These complexes are used as models for nucleohistones. At amino acid/nucleotide ratios r less than 1, the copolymers bind to DNA in a ratio of one amino acid residue per nucleotide, and such binding stabilizes the DNA double helix against thermal denaturation relative to the unbound regions. The leucine residues in the copolymers stabilize the bound portion of the complex against thermal denaturation but to a lesser degree than does poly(L-lysine). This study confirms the hypothesis that absorption melting profiles reflect only the change in secondary structure (helix-coil transition) of DNA. It was found that, in the absence of a higher ordered structure (condensed), the CD melting profile also reflects this same conformational transition, and the melting temperatures, Tm, in CD are equal to those in absorption. However, when a higher ordered structure (tertiary) exists in the complex, then the CD melting profile will be dominated by the structural transitions related to the melting of the higher ordered asymmetric structure in the condensed state, followed by the melting of the secondary structure. Under such circumstances, the Tm obtained from absorption may be slightly different from that of the CD, since only the secondary structural changes are being reflected in absorption. The relevance of these studies to the structure of chromatin is discussed.


The affinity labeling of amino acids in or about the active center of DNA-dependent DNA polymerase I. The use of an affinity label and an inhibitor that shows relative specificity for one amino acid has led to the identification of two amino acid residues in or near the active center of DNA-dependent DNA polymerase I. [35S]-beta-D-Ribosyl-6-methylthiopurine periodate oxidation product ([35S]MMPR-OP) and [14C]phenylglyoxal ([14C]PG) were used to elucidate the presence of a single lysine and arginine in or about the active center of the enzyme.


Sequence homologies in mammalian 5.8S ribosomal RNA. Oligonucleotide products of complete pancreatic or T1 RNase digestion or partial T1 RNase digestion of HeLa cell (human) and MPC-11 cell (mouse) 5.8S rRNA are identical with those obtained from Novikoff hepatoma (rat) 5.8S rRNA except for minor differences at the termini. pCp is the only major 5' terminus of both human and mouse RNAs; both pGp and pCp 5' termini were found in rat 5.8S RNA. Furthermore, HeLa cells contain C-U-U at the 3' end rather than the C-U terminus of mouse and rat. The results indicate that the nucleotide sequence has been highly conserved during the evolution of mammals and suggest that, as reported for 5S rRNA, this sequence is essentially constant throughout the Mammalia.


Isolation and structure of somatostatin from porcine hypothalami. The isolation and structure of somatostatin (GH-RIH) from pig hypothalami are described. This hormone was purified by preparative gel filtration, solvent extraction, countercurrent distribution in two solvent systems, ion-exchange and partition chromatography, and analytical gel filtration. The somatostatin activity was followed by in vitro bioassays and a radioimmunoassay. The isolated product was homogeneous chromatographically and had biological and immunological properties similar to synthetic somatostatin corresponding to the ovine hormone. The primary structure of porcine somatostatin was shown to be H-Ala-Gly-cyclo-(Cys-Lys-Asn-Phe-Phe-Trp-Lys-Thr-Phe-Thr-Ser-Cys)-OH. Other immunologically and biologically active form(s) of somatostatin were also detected.


Regulation of 3-hydroxy-3-methylglutaryl coenzyme A reductase activity and the esterification of cholesterol in human long term lymphoid cell lines. The regulation of the rate-controlling enzyme in cholesterol biosynthesis and of the incorporation of [14C]oleate into cholesterol esters were studied in established lymphoid cell lines from normal subjects and compared with that of eight patients with genetic abnormalities of lipid metabolism. The activity of 3-hydroxy-3-methylglutaryl coenzyme A reductase, the rate-controlling enzyme in cholesterol biosynthesis, increases in lymphoid cell lines derived from normal subjects after the culture medium is changed to a lipid deficient medium and reaches peak activity after 48 hr. The addition of whole serum and of low density lipoproteins to cell lines derived from normal subjects suppressed 3-hydroxy-3-methylglutaryl coenzyme A reductase activity by 50%, but failed (almost completely) to suppress the activity in the lymphoid cell lines derived from two patients with homozygous familial hypercholesterolemia. When 7-ketocholesterol was added, the activity of 3-hydroxy-3-methylglutaryl coenzyme A reductase was markedly suppressed in both normal and abnormal lymphoid cell lines. Lymphoid cell lines derived from patients presumably heterozygous for familial hypercholesterolemia were difficult to distinguish from normal cells in these studies. The incorporation of [14C]oleate into the fatty acid fraction of cholesteryl esters was stimulated by the addition of the low density lipoproteins to the culture media of the lymphoid cell lines derived from the normal human subjects. The lymphoid cell lines derived from the patients with homozygous familial hypercholesterolemia showed no increase in [14C]oleate incorporation into cholesteryl esters even when a fourfold amount of low density lipoprotein was added to the media; a modest increase in [14C]oleate incorporation was observed in lymphoid cell lines from patients with heterozygous familial hypercholesterolemia. The results of these studies in lymphocyte cell lines are compared with the findings in cultured human fibroblasts obtained from normal subjects and from patients with homozygous familial hypercholesterolemia. Studies of the regulation of cholesterol biosynthesis in the apparently permanent lymphoid cell line maintained in suspension culture offer certain advantages over cultured skin fibroblasts, and, in addition, provide a second tissue for the study of genetic abnormalities from the same patient.


Osmium (VI) complexes of the 3', 5'-dinucleoside monophosphates, ApU and UpA. The dinucleoside monophosphates, ApU and UpA, react with potassium osmate (VI) and 2,2'-bipyridyl to form the corresponding oxo-osmium (VI) bipyridyl sugar ester in which the osmate group is bonded to the terminal 2',3'-glycol. Osmium (VIII) tetroxide and 2,2'-bipyridyl react with the dinucleosides to form the corresponding oxo-osmium (VI) bipyridyl heterocyclic esters which result from addition of the tetroxide to the 5,6-double bond of the uracil residue. Although capable of transesterification reactions, these heterocyclic esters are exceptionally stable toward exchange reactions in solution. No apparent exchange was observed after 1 month. This reaction thus seems promising for single-site osmium labeling in polynucleotides.


Protocatechuate 3, 4-dioxygenase from Acinetobacter calcoaceticus. Protocatechuate 3,4-dioxygenase (PCD) from p-hydroxybenzoate-induced cells of Acinetobacter calcoaceticus was purified by heat and protamine sulfate treatment, ammonium sulfate fractionation, DEAE-cellulose, and Sephadex G-200 column chromatography. The enzyme appears to be homogeneous by ultracentrifugation and acrylamide gel electrophoresis. This is the first report of PCD purified from Acinetobacter. For comparison, crystalline Pseudomonas PCD was also obtained. The enzymes from Acinetobacter and Pseudomonas are quite similar in their molecular weight, molecular size, and iron content. The specific enzyme activity of PCD from Acinetobacter is about one-third of that from Pseudomonas, despite their similar iron content. Visible and circular dichroism spectra indicate some conformational differences between these two enzymes. Protocatechualdehyde, a competitive deadend inhibitor, binds Pseudomonas PCD more effectively than Acinetobacter PCD. p-Hydroxymercuribenzoate, specific for free-SH groups, inhibits only Acinetobacter PCD and shows no effect on Pseudomonas PCD. Amino acid analyses reveal very low proline and methionine content with higher lysine, glutamic acid, and isoleucine compositions for Acinetobacter PCD. Other properties, including active center conformation, were studied and discussed.


A measurement of the fraction of chloroplast DNA transcribed during chloroplast development in Euglena gracilis. The fraction of chloroplast DNA transcribed at different stages of chloroplast development in Euglena gracilis was measured by RNA-DNA hybridization. Euglena cells were grown in the dark in a heterotrophic medium to stationary phase and then transferred to the light. Chloroplast development was monitored by the increase in the cellular chlorophyll content in the absence of cell division. Total cell RNA was isolated at various stages of chloroplast development, and hybridized in a vast excess to [125I]chloroplast DNA. The fraction of [125I]chloroplast DNA in the form of a duplex was monitored by chromatography on hydroxylapatite columns. The amount of RNA-DNA hybrid in the duplex mixture was determined by correcting for the contribution of DNA-DNA renaturation under the same conditions. The fraction of chloroplast DNA transcribed was calculated by multiplying by two the amount of single-stranded DNA in the form of an RNA-DNA hybrid. Prior to the initiation of chloroplast development (i.e., in dark grown cells) the fraction of chloroplast DNA represented as RNA transcripts in the cell is 0.53. As chloroplast development proceeds, the fraction of the chloroplast DNA transcribed decreases to 0.47. Experiments in which mixtures of various RNA samples were hybridized to the chloroplast DNA indicate that there is a small portion of chloroplast DNA transcribed at later stages of chloroplast development which is not represented as transcripts at the onset of chloroplast development. Melting properties of the RNA-DNA hybrids show that the RNA-DNA duplexes are slightly less stable than renatured [125I]chloroplast DNA.


Changes in the expression of the chloroplast genome of Euglena gracilis during chloroplast development. The transcription program from the chloroplast genome of Euglena gracilis Z during light-induced chloroplast development has been characterized by hybridization of total cell RNA to 3H-labeled chloroplast DNA. Pancreatic DNase activated, purified Euglena chloroplast DNA was enzymatically labeled by Escherichia coli DNA polymerase I with [3H]TTP as a substrate. The [3H]DNA 'hybridization probe" was characterized by the kinetics of its renaturation with purified chloroplast DNA, and the thermal stability of [3H]DNA-DNA, and [3H]DNA-RNA hybrids. The [3H]DNA was hybridized in trace amounts to total cellular RNA extracted from Euglena cells 0, 4, 8, 12, 24, 48, and 72 h after the onset of chloroplast development. A large percentage (17%) of the chloroplast genome was found to be transcribed in dark adapted cells. Development is marked by an initial decrease in the fraction of the genome transcribed followed by an increase to 23% transcribed at the end of 72 h of light growth. Chloroplast RNA transcripts were also characterized by the kinetics of their hybridization to chloroplast DNA. The chloroplast specific RNA population is composed of three abundance classes, and the R0t1/2 for each class varies during the early stages of chloroplast development.


On the analysis of circular dichroic spectra of proteins. A new method is presented for analyzing circular dichroism spectra. The method employs integrals over the data and calculates the alpha-helical, beta-sheet, and random coil content of the proteins from such integrals. It is shown that the analyzed alpha-helical content is usually reliable to within 5%, beta-sheet values are somewhat less reliable, and random coil values are least reliable. Curve fitting techniques are shown to be misleading. The method has a number of advantages over existing procedures.


Synthetic flavinyl peptides related to the active site of mitochondrial monoamine oxidase. I. Chemical and spectral properties. Various 8 alpha-sulfur-linked peptides related to the flavinyl peptides isolated from mitochondrial monoamine oxidase were synthesized in high yield and purity. The peptides, protected by an acetyl-blocking group on the amino terminus, were synthesized by conventional liquid-phase techniques and coupled to a tetraacetylriboflavin derivative activated in the 8alpha position. In some cases, the ribityl side chains of the flavinyl peptides were selectively deacetylated. In other cases, the thioether functions were oxidized to form sulfones. These flavinyl peptides were studied by uv-visible absorption and circular dichroic spectroscopies. A close correspondence in spectroscopic and other chemical properties indicated the identity of the synthetic and naturally obtained flavinyl peptides. Differences between the tetraacetylriboflavinyl and riboflavinyl peptides indicate an interaction between the ribityl side chain and thioether function in aqueous media. Evidence was obtained for an intramolecular complex between the tyrosyl and isoalloxazine moieties in aqueous media. Substitution in the 8alpha position was accompanied by an impairment of the protonation of the N1 position of the isoalloxazine ring and a lowering of the redox potential relative to the parent 8-methyflavins.


Kinetics of deoxyhemoglobin subunit dissociation determined by haptoglobin binding: estimation of the equilibrium constant from forward and reverse rates. Deoxyhemoglobin tetramers dissociate into dimers very slowly, with half-times on the order of several hours. It is demonstrated that absorbance changes in the Soret region which accompany this dissociation and persist upon binding of haptoglobin 1-1 to the dissociated dimers can be used for accurate kinetic determinations over the necessarily long periods required for study. This method of study for the slow reactions depends upon long-term spectral integrity of the reaction mixtures and upon accurate measurement. The variation in rate constants determined by this procedure has been correlated with variations in structural constraints at the dimer-dimer contact region. In the presence of 2,3-diphosphoglycerate the rate constant is decreased, consistent with the role of this effector in binding to both beta chains and stabilizing the constrained deoxy tetramer against dissociation into alphabeta dimers. With hemoglobin specifically modified (des-Arg-141alpha) to eliminate half the constraining salt links within the dimer-dimer contact region, the dissociation rate is increased by approximately three orders of magnitude. In hemoglobin S where the amino acid substitution is not directly in the intersubunit contact region of interest, the dissociation rate is found to be approximately the same as that for hemoglobin A. Combination of the dissociation rate constants determined by haptoglobin binding with stopped-flow determinations of the rate constant for reassociation of dissociated dimers provides an estimate of the equilibrium constant, 0K2, for the deoxyhemoglobin dimer-tetramer equilibrium. This estimate is independent of any assumptions regarding other energetic quantities, and yields a value of 2.54 +/- 0.7 X 10(10)M-1 (heme) in 0.1 M Tris-HCl, 0.1 M NaCl, and 1 mM EDTA, pH 7.4, 21.5 degrees C. Thus the intersubunit contact energy is -14.0 +/- 0.2 kcal/mol of heme. The stabilization energy between deoxy and oxy tetramers is found to be approximately 6.4 kcal/mol, under these conditions.


Exposure of tryptophanyl residues in proteins. Quantitative determination by fluorescence quenching studies. Acrylamide is an efficient quencher of tryptophanyl fluorescence which we report to be very discriminating in sensing the degree of exposure of this residue in proteins. The quenching reaction involves physical contact between the quencher and an excited indole ring, and can be kinetically described in terms of a collisional and a static component. The rate constant for the collisional component is a kinetic measure of the exposure of a residue in a protein, and values ranging from 4 X 10(9) M-1 S-1 for the fully exposed tryptophan in the polypeptide, adrenocorticotropin, to less than 5 X 10(8) M-1 S-1 for the buried residue in azurin have been found. Static quenching is readily detected in proteins that are denatured, or contain only a single fluorophor. Quenching patterns for most multi-tryptophan containing proteins are difficult to analyze precisely, but qualitative information can, nevertheless, be extracted. Applications of this probing technique for monitoring protein conformational changes, such as the acid-induced expansion of human serum albumin, and inhibitor binding to enzymes, are presented. The value of this method lies in its ability to sense not only the steady-state exposure of a residue in a protein, but also its dynamic exposure.