Enzyme polymorphism and species discrimination in fruit flies of the genus Dacus (Tephritidae). Sympatric populations of D. tryoni and D. neohumeralis are difficult to completely distinguish taxonomically. Using five pigmentation characters, each of some taxonomic value, a small proportion of individuals cannot be assigned to either species nor definitely classified as hybrids. To aid in species discrimination and hybrid identification gene frequencies in natural populations were estimated at three polymorphic protein loci, an alcohol dehydrogenase (Adh), an octanol dehydrogenase (Odh) and an esterase (E-2). Samples of flies were taken from four sites spread over 1200 miles along the Australian eastern coast. Within each species allelic frequencies at each locus were largely the same at all localities. Consistent differences in gene frequencies between species occurred at all three loci, strongly supporting the hypothesis of two distinct gene pools. The Adh locus best discriminated between species with a unique allele occurring in D. neohumeralis at a frequency of 0-85. None of the loci showed complete differentiation and hence it was not possible to find a quick and easy method to distinguish the species nor to detect field hybrids. Directional selection of laboratory populations for a change in callus colour (the best pigmentation character for separating the species) indicated that at the Adh and E-2 loci frequencies of major alleles were not genetically associated with major genes for callus colour. Thus genotype determination at these loci when considered together with pigmentation characters may be valuable taxonomically for further distinguishing between the species.


Inheritance of some sweat gland and hair follicle characteristics in cattle. Using measurements made in cows in the herds of the Hannah Research Institute (Ayrshire), the West of Scotland Agricultural College (Ayrshire and Friesian) and in the twin herd of the Animal Breeding Research Organisation (Ayrshire), repeatability and heritability estimates were obtained for three hair follicle and four sweat gland traits. Average repeatability was high (50-70%) for all characters except angle of slope of the hair (18%). Heritability estimates were extremely variable among the different herds and methods of measurement but there was evidence of considerable genetic variation, particularly for sweat gland traits. The most consistent heritability estimate (30-45%) was given by the ratio of sweat gland length to diameter. The potential of skin types for the selection of cattle for tropical regions is discussed.


The effect of pre-partum milking on the transfer of immunoglobulin into mammary secretion of cows. The significance of local effects associated with mammary involution on transfer of immunoglobulin and especially on the selective transfer of IgG1 into mammary secretion of cows approaching parturition has been determined. This was carried out by measuring the changes in the concentration of IgG1, IgG2, IgM and IgA in serum and mammary secretion of 5 cows in which two mammary glands were milked continuously (twice daily) during the period preceding parturition, while the other two glands were allowed to undergo normal involution. In the secretion of unmilked glands of all cows there was a substantial increase in the concentration of IgG1 as cows approached parturition. In contrast, the increases in the concentration of IgG1 and in the selective index for IgG1 of milked glands were either virtually non-existent (1 cow) or generally reduced in magnitude and delayed in time of onset (4 cows). It is clear from the results that continued milking of a mammary gland throughout pregnancy tends to maintain milk production in the milked gland and at the same time reduces the massive selective transfer of IgG1 into secretion of that gland.


The origin of the immunoglobulins in intestinal lymph of sheep. Various immunoglobulins were labelled with radioactive iodine and their distribution between intestinal lymph and plasma followed in order to determine the origin of the immunoglobulins found in intestinal lymph. By comparing specific activities in plasma and lymph, it was computed that 25 percent of the IgG1 and IgG2 and 90 percent of the IgA in intestinal lymph were locally synthesised. The results suggest that virtually all of the IgA and a proportion of the IgG1 computed to be synthesised locally were derived from plasma cells of corresponding specificity in the lamina propria of the intestine.


Some evidence for the maturity of peripheral adrenergic nerves in new-born guinea-pigs. The fluorescence histochemical technique of Falck and Hillarp revealed a similar distribution and density of peripheral adrenergic nerves in new-born and adult guinea-pigs. The accumulation of tritiated noradrenaline by tracheae from new-born guinea-pigs, assumed to be uptake into adrenergic nerves, was not less than the accumulation by tracheae from adult animals. There was equal potentiation by cocaine (1 x 10(-5)M) of responses to noradrenaline on tracheal chain preparations taken from new-born and adult guinea-pigs. The evidence supports the hypothesis that the guinea-pig has a functional, well differentiated peripheral adrenergic nervous system at birth. This would account for the apparent inability to produce a long-lasting sympathectomy by administration of 6-hydroxydopamine to new-born guinea-pigs.


Adrenergic innervation of human mesenteric blood vessels. A fluorescent histochemical technique has been applied to study the adrenergic innervation of human superior mesenteric arteries obtained at autopsy. Specific catecholamine fluorescence was demonstrated in the smaller branches of this artery taken from three infants and one child. No specific fluorescence was seen in arteries from three adult subjects.


Inhibition by serum of autoimmune aspermatogenic orchitis. Inhibition by serum of experimental autoimmune orchitis (EAO) was studied in guinea-pigs. It was found that the capacity of an autoantigen, antigen P, purified from guinea-pigs' spermatozoa, to produce lesions of EAO could be inhibited by mixing antigen P with a small amount of normal human serum before injection into guinea-pigs. In protected animals, cell-mediated immunity and humoral antibodies to antigen P were also significantly suppressed.


The diagnosis of pregnancy in sheep by abdominal palpation. Pregnancy diagnosis in Merino ewes by abdominal palpation was 80 to 95 percent accurate in ewes 90 to 130 days pregnant. The ease with which the foetus could be palpated increased with increasing gestational age. Animals in store body condition were more easily diagnosed than those in forward store condition. Withholding feed and water for 12 to 24 hours increased the ease of diagnosis. One operator and two assistants could perform the technique at a rate of 150 to 200 sheep per hour. The animals were held in the sitting position and no special restraining apparatus was necessary. The potential for using this technique may be associated with investigations of reproductive wastage or the selection of pregnant animals for preferential management during drought conditions.


Control of ovine lupinosis: experiments on the use of fungicides. Experiments were conducted in 4 successive years to assess whether certain fungicides when applied to lupins would control the disease, ovine lupinosis. Results were variable, ranging from failure of fungicidal sprays to prevent the disease in 1969/70 to partial success in 1970/71. Fumigation with methyl bromide was very effective. It is concluded that none of the fungicides tried could be considered as a practical means of controlling the disease.


The use of fluff counts in a study of hygiene in Queensland hatcheries. During 1972, 333 fluff samples were tested from 13 Queensland hatcheries and assessed according to the English standards for total count, coliforms and fungi. They were also assessed as being "standard" or "substandard", using a combination of the criteria of the English system. All hatcheries had at least 2 substandard samples and all the samples from 2 hatcheries were substandard.


Bovine melioidosis in South-Eastern Queensland. Acute fatal infection with Pseudomonas pseudomallei caused pneumonia, placentitis and endometritis in a pregnant cow. Pneumonia was also present in the foetal lung. Mononuclear cell response with extensive karyorrhexis occurred in maternal and foetal lung and the same cellular pathology, but with diffuse distribution, was responsible for plaques on the endometrium. A more chronic disease with encapsulated caseous lesions in the lung, together with arthritis, occurred in a bull on the same property. Nutritional and physical stress caused by a flood were thought to be predisposing factors. An unusually wet summer with prolonged flooding apparently provided suitable environmental conditions for saprophytic growth of Ps. pseudomallei in an area far south of the region in which infection of animals with this organism commonly occur.


The Maudsley reactive and nonreactive strains of rats: a survey. Experiments with two strains of rats, the Maudsley Reactive and Nonreactive, developed in London, England, and which were performed during 1964--1974 by a variety of investigators are summarized in a table. It is concluded that the results support the strains' standing as exemplars of differences in emotional reactivity.


Albinism and auditory function in the laboratory mouse. II. Effects of acoustic priming and cross-fostering. Albino (c/c) and nonalbino (+/c and +/+) congenic C57BL/6J mice were examined for the effects of acoustic prestimulation (priming) on audiogenic seizures. While no genotypic-specific effects were noticed 1 day after priming, major effects were observed in separate groups of mice tested 5 days after priming. The c/c mice were most susceptible to audiogenic seizures, and no differences were observed between +/c and +/+ mice. While cross-fostering did not change this relationship, it provided protection from acoustic trauma is considered inconclusive because of the interaction of innate- and priming-induced audiogenic seizures in the +/c and c/c mice.


Genetic component in learning ability in bees. Twenty-five bees, five from each of five hives, were trained to collect food at a table. When the bee reached the table, time was recorded for 12 visits. Then a blue and yellow pan was substituted for the original metal pan, and time and correct responses were recorded for 30 trips (discrimination phase). Finally, food was taken from the pan and extinction was recorded as incorrect responses for 20 visits. Variance analysis was carried out, and genetic variance was undetected for discrimination, but was detected for extinction. It is concluded that learning is very important for bees, so that any impairment in such ability affects colony survival.


Behavior genetic analysis of mouse emotionality. III. The diallel analysis. A total of 775 pure-strain and F1 mice were obtained from a 6 X 6 diallel mating plan. Previous factor analysis of 42 measures of emotionality identified 14 behavioral factors, ten of which were interpretable. Hayman's analysis of variance and analysis of diallel crosses were applied to each of the factors. In general, the findings indicate that the mode of inheritance for emotionality factors is polygenic and in the direction of complete dominance. However, a major point of this investigation is that the mode of inheritance of highly complex behavior such as emotionality depends on the factor in question. For example, the breakdown of dominance effects by factor was as follows: partial dominance--Motor Discharge, Food Motivation, Tunneling-2, and Activity Level (males); complete dominance--Audiogenic Reactivity, Underwater Swimming (males), and Activity Level (females); overdominance--Acrophobia, Territorial Marking (males). Additional findings include directional dominance for Underwater Swimming and Audiogenic Reactivity, and significant sex differences for eight of the 14 factors.


Differences in mating propensities: some models for examining the genetic consequences. Several models of mating behavior are described. The rates at which matings occur are described by differential equations. When several types of males are present with several types of females, the rates are described by a system of such equations. Different modes of pair formation result in different equations, and differences in mating propensities result in different constants in the equations. Two types of pair formation are examined: promiscuous pair formation and permanent pair formation. these models are found satisfactory when tested against observations of mating in flour beetles and houseflies. Some ways in which different mating propensities may affect the genetic structure of populations are examined in the light of these models.


Family resemblance in abilities: the Wechsler scales. This note reports data on parent-child and spouse resemblance on the Wechsler intelligence scales, the WISC and WAIS. Test data on parents and one male 10-year-old child from 55 Canadian families are used to estimate father-son, mother-son, midparent-son, and father-mother correlations on 11 comparable subscales and on the verbal, performance, and total IQ aggregates. Heritabilities for these same scales are estimated as the regression of offspring on midparent values.


Substrate specificity of Micrococcus luteus UV endonuclease and its overlap with DNA photolyase activity. The action of an endonuclease from Micrococcus luteus that operates on UV damage in DNA overlaps with that of DNA photolyase from yeast: homo- and heterocyclobutane dipyrimidines in DNA are substrates for both enzymes, but pyrimidine adducts or the "spore photoproduct" in DNA are not. As expected from this overlap, the action of the two enzymes is mutually interfering: single-strand nicks introduced by the endonuclease effectively preclude photoreactivation; conversely, formation of a photolyase-cyclobutane dipyrimidine complex can prevent nicking by the endonuclease.


Genetic exchanges induced by structural damage in nonreplicating phage lambda DNA. Genetic recombination between irradiated lambda phage and the unirradiated lambda prophage in homoimmune lysogens has been studied under conditions in which phage DNA replication and repair were controlled. The lambda phage were exposed to one of three treatments before infecting the lysogens: (a) 254-nm light, which produces pyrimidine dimers and other photoproducts; (b) 313-nm light with acetopheneone D, which produces thymine dimers and a different spectrum of other photoproducts; (c) 360-nm light with trimethylpsoralen, which produces monoadducts and cross-links. With both replication and excision-repair of the damaged phage DNA blocked, treatment b (acetophenone D) caused no significant increase in recombination, indicating that thymine dimers do not cause recombination if the DNA in which they are contained is not replicated. Treatment a (254 nm), producing the same total number of pyrimidine dimers, caused a marked increase in recombination. This indicates that photoproducts other than pyrimidine dimers produced by 254-nm light can cause recombination in the absence of replication. Treatment c (psoralen) caused a marked increase in recombination in wild type but not in uvrA and uvrB mutants. The frequency of recombination in two-factor crosses varied with marker separation in such a way as to suggest that cross-links can act over distances of at least 5% of the lambda genome to cause exchanges between pairs of relatively closely spaced markers. The psoralen photo cross-links and monoadducts initiate recombination only following the action of excision enzymes, which appears to release one arm of each cross-link, producing a gap with free strand ends. It may be these strand ends which induce recombination. The action at a distance of 5% of the lambda genome may reflect heteroduplex formation and the subsequent reduction to homozygosity of mismatched base pairs at genetic markers. Recombination between closely spaced markers in the P gene is reduced in strains carrying polA.


Formation of dimers in ultraviolet-irradiated DNA. Evidence has been obtained that in UV-irradiated native DNA, pyrimidine dimers are preferentially formed in long pyrimidine tracts. This effects is not the result of the existence of more dimerizable thymine in the long pyrimidine tracts. The preferential formation of dimers in long pyrimidine tracts is enhanced as the dose of irradiation is decreased. These results suggest that the formation of dimers in native DNA occurs by a cooperative mechanism. Quite likely, dimers are formed only in regions of native DNA that are locally denatured (breathing), in which the bases can be aligned. The formation of a dimer in such a breathing region would tend to lock it open and could lead to cooperative formation of dimers in such regions. If this mechanism for the cooperative formation of dimers is operative then it should be restricted to double-strand DNA. The pyrimidine tracts of irradiated single-stranded DNA all show virtually the same dimer content, irrespective of the length of the tract. These results are consistent with the hypothesis that dimers form cooperatively in breathing regions.


The radiobiology of DNA strand breakage. The yield of single-strand breaks in lambda DNA within lysogenic host bacteria was measured after exposure to 4-MeV electrons (50 msec) and rapid transfer (45 msec) to alkaline detergent. In nitrogen anoxia the yield was 1.2 X 10(-12) DNA single-strand breaks per rad per dalton, and under full oxygenation the yield increased to 5 X 10(-12) breaks per rad per dalton. A search for the presence of fast repair of strand breaks operating within a fraction of a second. Strand breaks produced in the persence of oxygen were repaired in 30-40 sec, while breaks produced under anoxia were rejoined even slower. A functional product from the po[A] gene was needed for the rejoining of the broken molecules. Intermediate levels of DNA strand breakage seen at low concentrations of oxygen are dependent on the concentration of cellular sulfhydryl compounds, suggesting that in strand breakage oxygen donors compete for reactions with radiation-induced transients in the DNA. Intercomparisons of data on radiation-induced lethality of cells and single-strand breaks in episomal DNA allow the distinction between two classes of radiation-induced radicals, R-1 and R-2, with different chemical properties; R-1 reacts readily with oxygen and N-oxyls under formation of potentially lethal products. The reactivity of oxygen in this reaction is 30-40 times higher than that of TMPN. R-2 reacts 16 times more readily that R-1 with oxygen under formation of single-strand breaks in the DNA. R-2 does not react with N-oxyls.


Postreplication repair of DNA in UV-irradiated mammalian cells. Some current controversies concerning the mechanism of postreplication repair in mammalian cells are discussed. We have found that two xeroderma pigmentosum cell lines normal in excision-repair are abnormal in postreplication repair. The rate of postreplication repair is slower than that in normal cells and is caffeine sensitive. In normal human fibroblasts, caffeine has little effect.


Effects of caffeine on postreplication repair in xeroderma pigmentosum cells. Compared to its effects on unirradiated cells, caffeine inhibited DNA chain elongation and joining in UV-irradiated xeroderma pigmentosum (XP) cells but not in irradiated normal human cells. The drug also inhibited the ability of XP cells to recover and make DNA of normal size at long times after irradiation.


Postreplication repair in human cells: on the presence of gaps opposite dimers and recombination. Human cells prelabeled with [32P]phosphate were exposed to UV and then pulse-labeled with [3H]thymidine. The DNA from these cells was subsequently treated with T4 endonuclease V, an enzyme which specifically nicks DNA at positions adjacent to pyrimidine dimers. Sedimentation in alkaline sucrose gradients revealed that both the DNA made before and that made after irradiation contained nuclease-sensitive sites, indicating that a recombinational process between these DNAs might be occurring during postirradiation incubation. Sedimentation in neutral sucros gradients showed that the molecular weight of native DNA remained unchanged for both DNAs upon endonuclease treatment, indicating that gaps opposite dimers are not necessarily formed after irradiation.


Formation and rejoining of DNA strand breaks in X (gamma)-irradiated cells in relation to the structure of mammalian chromatin. Mammalian cells usually possess the capacity to rejoin disruptions introduced into their deoxynucleoprotein structures by ionizing radiation. I believe that analyses of the strand-break-inducing and the strand-break-rejoining mechanisms operating on the DNA of irradiated cells can provide clues to the nature of the structure of mammalian chromatin in situ. In particular, I wish to consider evidence relevant to the idea that mammalian DNA contains special sites which are sensitive to radiation (Left and Sun, 1970; Lett et al., 1972), alkali (Lett et al., 1970), and perhaps other agents and treatments. This concept is usually referred to as the "subunit hypothesis." The present communication extends previous arguments along similar lines (Lett et al., 1972) with an evaluation of more recent data. Since these data have been, or will be, published in the open literature or elsewhere in this book, they will be described here only in general terms.


CHO cell repair of single-strand and double-strand DNA breaks induced by gamma- and alpha-radiations. Neutral and alkaline sucrose gradient sedimentation analysis was used to measure double- and single-strand breaks in the DNA of Chinese hamster ovary (CHO) cells exposed to either gamma- or alpha-radiation. After irradiation, cells were incubated for 15-180 min to test the ability of the cell to rejoin the DNA breaks. Essentially complete rejoining was observed for single-strand breaks induced by gamma- or alpha-doses below 20 krad and for double-strand breaks induced by gamma doses below 60 krad. Approximately 80% rejoining was observed for double-strand breaks induced by alpha doses below 40 krad. At higher doses, the repair system appeared to saturate in such a way that essentially no additional breaks were rejoined.


The repair of DNA double-strand breaks in mammalian cells and the organization of the DNA in their chromosomes. The molecular weight of native DNA has been accurately determined by the use of a semiautomated sucrose gradient system. A mondisperse size distribution (speed dependence free) of eighth-of-a-chromatid pieces [1.7 S 10(10) daltons, with 95% confidence (fiducial) limits of +/- 48%] was found. This size has been confirmed by viscoelastometry. Ionizing radiation rapidly breaks each of these pieces into about 21 subunits (again monodisperse) of 8 X 10(8) daltons each. With increaseing dose (greater than 2 krad) the subunits are themselves randomly broken down into even smaller pieces. Postirradiation incubation at 37 degrees C permits the cells to repair both DNA double-strand breaks and intersubunit linkages at the same dose-independent rate (T37) of about 55 min, the same rate as found in Micrococcus radiodurans. The repair data are compatible with a first-order-kinetics repair system, analogous to the post-UV excision-repair system, which becomes saturated at high doses (greater than 60 krad). Specially constructed "enzyme" gradients show that the linkages contain at least two protein molecules each covalently bound to the end of a subunit and linking the subunits together by a disulfide bond(s). Correlation of cell survival and DNA break kinetics yields two possible models. These are that the two-thirds of the lethal events which are due to improperly or unrepaired double-strand breaks result from either (1) a misrepair frequency of 3.5 X 10(-3) (rather high for a mutation frequency) or (2) the induction of a double-strand break in a single eighth-of-a-chromatid unit which is essential for survival but which cannot be repaired, possibly because the unit contains the double-strand break repair system gene(s).


Kinetics of the single-strand repair mechanism in mammalian cells. Alkaline sucrose gradient measurements of single-strand breaks from sublethal X-ray doses yield the same breakage efficiency as from lethal doses. Repair of the breaks is random, first order with a single rate constant, and characterized by 24 kcal/mole activation energy.


Damage-repair studies of the DNA from X-irradiated Chinese hamster cells. Sedimentation studies of the DNA-containing material released from Chinese hamster cells lysed on top of an alkaline sucrose gradient have shown these principal points: (1) After short lysis periods (e.g. approximately 60 min, approximately 25 degrees C), the DNA label from unirradiated cells sediments as a two-peaked pattern. The relative positions of these peaks are strongly dependent on centrifugal force. (2) With increasing lysis time, DNA lost from one peak (the "complex", the peak containing lipid) appears in the other (the "main peak"). (3) The same transition is effected, for a given lysis time, if prior to lysis cells are X-irradiated with small doses (from 100 to 700 rads). Since such doses are in the high survival range (approximately 80% to approximately 3%, respectively), an association between damage to the complex and survival is suggested. And (4) the cosedimentation of lipid and DNA in the complex is lost after doses that resolve the complex into main-peak DNA, while postirradiation incubation for repair results in a re-formation of the complex plus cosedimentation of lipid and DNA once again.


Direct evidence that pyrimidine dimers in DNA result in neoplastic transformation. A specific test for the biological role of UV-induced pyrimidine dimers in DNA is photoreactivation (PR). Fish contain large amounts of the PR enzyme. Portions of cell suspensions of tissue from various organs of the fish Poecilia formosa were exposed to UV radiation (254 nm), then injected into isogenic recipients. An incident fluence of 20 J/m2 resulted in 10% of the fish with large granulomas and 100% with thyroid carcinomas. If the irradiated cell suspension was illuminated with PR light before injection, the yields of both types of lesion were reduced approximately 10-Fold. If the PR light was given before the UV exposure, there was no reduction in the numbers of growths. These experiments show that pyrimidine dimers in DNA can lead to neoplastic transformation.


Genetic complementation analysis of xeroderma pigmentosum. To characterize the mutations in different unrelated xeroderma pigmentosum (XP) patients, a complementation test was performed using the technique of somatic cell hybridization. DNA repair following UV exposure was studied in multinuclear cells resulting from fusions between in vitro cultivated cells from different patients. The parental XP cells performed low or negligible levels of repair DNA synthesis, whereas in some combinations binuclear hybrid cells showed repair DNA synthesis as a result of complementation. The results indicate the presence of five different complementation groups in XP.


The use of human adenovirus 2 in the study of the xeroderma DNA-repair defect. Ultraviolet-irradiated adenovirus 2 assayed by counting plaques on monolayers of human fibroblast strains is up to 30-fold more sensitive than normal if the strains used as viral hosts are prepared from persons having xeroderma pigmentosum. This plaque assay has been used as an extremely discriminating technique in the study of the xeroderma repair defect. With this assay, every xeroderma fibroblast strain tested has been found to exhibit a DNA-repair defect, including those previously judged by other methods to have normal DNA repair.


Cytotoxic and mutagenic effects of carcinogenic aromatic amides and polycyclic hydrocarbons and ultraviolet irradiation in normally repairing and repair-deficient (xeroderma pigmentosum) diploid human skin fibroblasts. The cloning ability of fibroblasts taken from a xeroderma pigmentosum patient proved 2.5-3.5 times more sensitive to the cytotoxic effect of active derivatives of carcinogens or to UV irradiation than that of normal cells. They also exhibited a corresponding 2.5- to 2.5-fold greater increase in the frequency of induced mutations to 8-azaguanine resistance per survivor, which might have been expected since these XP cells exhibit less than 20% of the DNA-repairing capacity of the normal cells following exposure to such DNA-damaging agents.


Lack of direct correlation among repair, oncogenesis, and lethality in cultured synchronized mouse fibroblasts treated with N-methyl-N'-nitro-N-nitrosoguanidine. The repair of single-strand breaks induced by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) in mouse embryo fibroblast DNA was studied using an alkaline sucrose sedimentation procedure with cells synchronized by arginine deprivation. Parallel studies in synchronized cells examined the effects of MNNG on malignant transformation and cell death. Cells in late G1 were maximally transformed, while cells in S-phase were maximally killed; by contrast, the repair capacity in both cases was similarly rapid. Arginine-deprived cells showed a low level of DNA repair, but the extent of cell death and transformation was comparable to that in rapidly repairing cells in G1 and S, respectively. Thus, in this system there is no direct correlation among DNA repair, cell transformation, and lethality.


DNA repair and life span of mammals.

DNA repair and life span of mammals. The ability of fibroblasts to perform unscheduled synthesis (a measure of excision-repair) after UV irradiation was measured autoradiographically for seven mammalian species at several times after UV irradiation. The initial rate and the maximum incorporation of [3H]dThd increased with the life span of the species.


Radiosensitization of a human cell line lacking repair replication. A human cell line has been isolated that is deficient in X-ray-induced repair replication. The slope of the radiation survival curve is greater in the presence of the anthracycline antibiotic, adriamycin. The results suggest that radiosensitization by DNA-binding drugs is more probably related to DNA strand breakage phenomena than to the polymerase step of excision-repair.


A repressible DNA-repair system in mouse neuroblastoma cells. Differentiated mouse neuroblastoma cells are extremely sensitive to UV light even through they can undergo excision-repair. A postreplication repair system present in proliferating cells is reversibly repressed in differentiated neuroblasts, and its genetic control is not coupled directly with DNA replication.


DNA repair and UV resistance in human melanoma. Human melanoma cells are highly resistant to 254-nm light. Resistance appears to depend on their ability to continue replication after high UV doses due to the presence of a very efficient postreplication repair system, while excision-repair is of relatively minor importance.


Heterodromia in accessory A-V connections. In 15 patients with WPW-syndrome the atrio-ventricular and ventriculoatrial conduction was studied by recording of intracardiac potentials during atrial and ventricular pacing. Typical differences in the patterns of normal and accessory A-V conduction identified accessory V-A conduction in 13 patients. According to the evaluation of accessory A-V and V-A conductivity by high rate pacing the patients studied can be divided into three groups: Group I (5 pat): equally good accessory A-V and V-A conductivity. Group II (5 pat): good accessory A-V and impaired accessory V-A conductivity. Group III (5 pat): impaired accessory A-V and good V-A conductivity. In group I the course of investigation was repeated after the application of Ajmaline. The distinct heterodromia in group II and III and the different behaviour of the accessory A-V and V-A conduction after Ajmaline can be explained by the in vitro experiments of Fuente (3). According to our results and to the finding that an excellent accessory V-A conduction is a presupposition for the initiation of supraventricular re-entry tachycardia, it seems mandatory to analyze accessory A-V and V-A conduction properties as well.


Stroke volume from central aortic pressure? A critical assessment of the various formulae as to their clinical value. Pulsecontour methods remain a potentially attractive approach for the calculation of stroke volume, since they might provide such information on a beat to beat basis, after a single calibration. In order to test the clinical value of this hypothesis stroke volume estimates from six different pulsecontour formulae were compared with stroke volume values obtained with an electromagnetic flowmeter in 10 pigs. Each of the formulae failed to confirm its usefulness under circumstances mimicking clinical conditions. The calibration constant obtained during control states varied widely (+/- 25%). In many instances polsecontour formulae predicted changes in stroke volume in a direction opposite from those measured. The need for recalibration was so frequent that the calibration merthod itself proved often sufficiently informative. It is concluded that in intensive care units pulsecontour formulae cannot contribute to the care of the patient. Its popularity is not justified and its increased use since the introduction of computers is not warranted.


[Pulmonary microembolism: pulmonary hemodynamics following trauma and hemorrhage (author's transl]. Standardized bone trauma by means of open osteotomy is performed on both hind legs of 16 out of 24 anaesthetised mongrels. During the following 6 hours the most important parameters of blood coagulation and the serum lipids are estimated at regular intervals. Subsequently in a number of the animals 50% of the total blood volume is withdrawn continuously over a period of one hour. All animals without the preceding trauma survive the hemorrhage. The animals in the trauma group die on the average 42 minutes after the beginning of the hemorrhage. The trauma causes an acute decrease in total platelet count (GTZ) to 40% of the pretraumatic value. During an initial phase of hypercoagulability there is a formation of reversible microaggregations containing platelets and fibrin, caused by an increased turnover of coagulation factors. Secondary fibrinolysis develops in the traumatised animals. A further increase in coagulation is caused by the following hemorrhage. In combination with decreased and inhibited fibrinolysis, a disseminated intravascular coagulation state is found and results in irreversible pulmonary microthrombosis. Massive pulmonary fat deposits cannot be found histologically in spite of an increase in serum triglycerid levels to 35% above the pretraumatic values. In dogs great amounts of fat are filtered by the glomeruli and are demonstrable in the tubular epithelium. Histological examinations show a marked disseminated pulmonary microthrombosis of platelets, fibrin and fat in those animals with trauma and hemorrhage. Only the accompanying hypovolemia produces the characteristic histologic changes of the so-called Pulmonary Microembolism Syndrome.


Pacing studies after cardiac surgery.

Pacing studies after cardiac surgery. The diagnostical use of pacemaker after cardiac surgery is presented. Temporary pacemaker electrodes have been inserted during surgery into the wall of atrial and ventricular myocardium. With the aid of these electrodes, an analysator wire of 6 volts, and a Medtronic 5840 type pacemaker electrophysiological studies have been performed. The diastolic  and supernormal stimulation threshold, the duration of atrial and ventricular relative refractory period were measured, the clinical significance of latency was analysed. It has been found that decrease of stimulation threshold, shortening of relative refractory period, and appearance of latency phenomenon promote arrhythmias. By investigating the conduction capacity of atrioventricular conduction system, latent conduction disturbances could be revealed, and a significant difference could be demonstrated between the atrioventricular conduction of WPW syndrome and that of other kinds of PR interval shortening. In addition the optimal heart rate requirement (optimal pacing rate) following heart surgery was defined. These parameters present more precise information on the electrophysiological condition of the heart than does the generally used ECG monitoring. When these parameters are repeatedly determined, the significance of patient's arrhythmias can be evaluated more safely and accurately; in a number of cases, even in the absence of any rhythm disturbances, impending arrhythmias can be predicted. "Pacemaker monitoring" of the postoperative heart patients, therefore, affords greater possibility for preventing the development of major cardiac arrhythmias.


Systemic and coronary hemodynamic effects of Abbott (40557) and its interaction with aminophylline. Adenosine is a naturally occurring substance with potent coronary vasodilator action. However, its action is of short duration due to its rapid inactivation in blood and other tissues (1). If used for therapeutic purposes a prolonged duration of action might be desirable. A recent adenosine derivative (Abbott 40557) ethyl-adenosine-5'-carboxylate hydrochloride1) has marked and prolonged coronary vasodilator activity (2,3). The present report concerns the coronary and systemic hemodynamic and metabolic effects of A 40557 and attempts to determine whether, like adenosine, its action is enhanced by dipyridamole (4,5), hexobendine (6), and Cassella 7657 (7) or inhibited by aminophylline (8,9).


The effect of carbocromene on strophanthin-induced ventricular tachycardia in dogs. The antiarrhythmic effect of carbocromene (Intensain) was studied in 17 anaesthetized dogs. Ventricular tachycardia was induced by infusion of K-strophanthin (mean dose: 154 mug/kg i.v.). In 25 out of 26 experiments carbocromene (4 mg/kg i.v.) was effective. Ventricular tachycardia was converted to sinus rhythm in 16 experiments, to atrial tachycardia in 6 experiments and to junctional tachycardia in 3 experiments. The favourable effect started 8 to 50 seconds after the injection with lower doses of carbocromene (3 and 2 mg/kg i.v.) in time intervals of 5 minutes resulted in similar positive effects leading after 2 or 3 injections finally to a second phase of drug effect where ventricular tachycardia was strongly modified for about 30 minutes. The results favour the therapeutic use of this drug in patients with arrhythmia especially with arrhythmias caused by digitalis.


Studies on live rubella vaccine. VI. Seroepidemiological surveillance and immunization of adolescents in high school. The rubella seroimmunity status of a total of 1,204 students aged 12 to 19 in a junior and a senior high school in Osaka district was surveyed. Among these, 487 students (40.5%) were found to be seronegative (less than 1 : 8) by the hemagglutination inhibition (HI) test. A total of 287 students were immunized with live rubella vaccine, Biken lot No.7233. This caused an increased titer in all except one of the 262 seronegative students, while among 25 students with an initial HI antibody titer of 1 : 8 it caused more than 4-fold increase in 20 and 2-fold increase in 5. The vaccine caused no clinical manifestations, such as fever, rash or arthralgia.


A radio-ligand receptor assay for the long-acting thyroid stimulator. Inhibition by the long-acting thyroid stimulator of the binding of radioiodinated thyroid-stimulating hormone to human thyroid membranes. Highly purified bovine TSH (thyroid-stimulating hormone) was labelled with 125I by using very low concentrations of chloramine-T. Human thyroid membranes prepared by discontinuous sucrose-density-gradient centrifugation were homogeneous on examination by electron microscopy. Incubation of radioiodinated TSH with the membranes showed that radioactivity could be bound to the membranes. Under the experimental conditions described here, binding was dependent on time and temperature and was a saturable phenomenon. Preincubation of the membranes with unlabelled hormone inhibited the subsequent binding of 125I-labelled TSH. Similarly, inhibition by the long-acting thyroid stimulator also showed a saturation behaviour. A rapid and sensitive method for the detection of the long-acting thyroid stimulator is described.


The nature of the collagen cross-links in bone in the chronic uraemic state. The cross-links from NaB3H4-reduced bone collagen of chronically uraemic rats and pairfed controls were compared. The ratio of the reduced cross-links deltadelta'-dihydroxylysinonorleucine to delta-hydroxylysinonorleucine was significantly increased in the uraemic animals. The observed increment in the dihydroxylysinonorleucine:hydroxylysinonorleucine ratio was accentuated as the uraemic state advanced. The data indicate that osteodystrophy of chronic renal insufficiency is characterized by an alteration of the quantitative relations between cross-links and aldehydic precursors of bone collagen.


Equisetum (horsetail) ferredoxin: characterization of the active centre and position of the four cysteine residues in this 2Fe-2S protein. Analysis of the ferredoxin of the primitive vascular plant Equisetum indicates that the cysteine residue normally found at position 18 of plant-type ferredoxins is replaced by a valine, although the spectroscopic properties of the ferredoxins are unaffected. It is concluded that the iron--sulphur cluster in plant-type ferredoxins is attached to cysteine residues 39, 44, 47 and 77.


Preparation of the lactate oxidase apoenzyme and studies on the binding of flavin mononucleotide to the apoenzyme. 1. Lactate oxidase from Mycobacterium smegmatis is completely resolved into free flavin and apoenzyme by treatment with acid (NH4)2SO4. 2. Reconstitution involves rapid binding of FMN, but the recovery of enzyme activity was slower and appeared to be biphasic. 3. The preparation of the holoenzyme obtained differs from the native enzyme in specific activity, extinction coefficients and mobility on disc-gel electrophoresis. 4. Dialysis of this reconstituted enzyme in 0.1 M-sodium phosphate buffer, pH 7.0, at 0 degrees C for 1 week yields a preparation which closely resembles the native enzyme.


The steady-state kinetics of peroxidase with 2,2'-azino-di-(3-ethyl-benzthiazoline-6-sulphonic acid) as chromogen. The chemical nature of the important new chromogen ABTS [2,2'-azino-di-(3-ethyl-benzthiazoline-6-sulphonic acid)] is described together with an account of the redox and spectroscopic properties of the system ABTS--H2O2--peroxidase. Keq. is calculated and a study of the steady-state kinetics over a whole range of substrate concentrations is reported. By using novel methods of kinetic analysis, an interpretation of the results is given which requires some extension of the classical peroxidase mechanism.


The reciprocal exclusion by L-dopa (L-3,4-dihydroxyphenylalanine) and L-tyrosine of their incorporation as single units into a soluble rat brain protein. Several compounds, structurally and metabolically related to phenylalanine and tyrosine, were tested for their effects on the incorporations of phenylalanine and tyrosine as single units into a protein of the soluble subcellular fraction of rat brain. Of the compounds tested, only L-dopa (L-3,4-dihydroxyphenylalanine) inhibited these incorporations. Further, L-dopa was incorporated into a protein of the same fraction in such a way that it excluded the incorporation of tyrosine as a single unit. Conversely, tyrosine inhibited and excluded the incorporation of L-dopa. The incorporation of L-dopa required ATP (apparent Km = 0.23mM), KCl (apparent Km = 20mM) and MgCl2 (optimal concentration range, 5-16mM). These requirements were similar to those previously determined for the incorporation of tyrosine and phenylalanine. The inactivation rate of the enzymic systems for L-tyrosine and L-dopa incorporations, when kept at 37 degrees C, was the same for both amino acids (half-life = 80 min). It is suggested that the acceptor for the incorporation of dopa is the same as that for the incorporation of tyrosine.


Studies on ram acrosin. Fluorimetric titratiion of operational molarity with 4-methylumbelliferyl p-guanidinobenzoate. 1. Titration in sodium barbiturate buffer of acrosin, a serine proteinase from sperm acrosomes, with the ester substrate 4-methylumbelliferyl p-guanidinobenzoate gave rise to an incomplete 'burst' of 4-methylumbelliferone. Studies of the effects on the reaction of activators of acrosin (Ca2+, water-miscible solvents) showed that titrations carried out in barbiturate buffer containing 1M-CaCl2 and diluted with 0.2 vol. of dimethylsulphoxide produced a rapid quantitative burst within 4 min at 20 degrees C. 2. The net post-burst production of 4-methylumbelliferone was neglibible because (a) the acyl-enzyme was very stable, and (b) the slow post-burst formation of 4-methylumbelliferone (turnover of acyl-enzyme) was virtually equal to the slow photolytic destruction of 4-methylumbelliferone that was liberated during the burst. 3. The standard procedure permits titrations of 20-100pmol of acrosin, i.e. amounts normally taken for conventional rate assays, and with these amounts the impurities present in crude enzme fractions did not interfere. The burst was judged to be quantitative on the basis of comparisons with titrations of acrosin with p-nitrophenyl p'-quanidinobenzoate. 4. The burst reaction of trypsin with the 4-methylumbelliferyl ester was inhibited by high Ca2+ concentrations and by dimethyl sulphoxide. 5. The association and dissociation of complexes of both acrosin and trypsin with protein-type inhibitors (Kunitz pancreatic trypsin inhibitor and a spermatozoal acrosin inhibitor) are rather slow. It is thus possible, in certain cases, to use the ester to titrate both total enzyme in an inhibitor-enzyme mixture and net enzyme, i.e. the stoicheiometric excess of enzyme over inhibitor.


Studies on ram acrosin. Isolation from spermatozoa, activation by cations and organic solvents, and influence of cations on its reaction with inhibitors. 1. A simple method is given for isolating from ram spermatozoa a water-soluble form of acrosin (a trypsin-like enzyme) which is about 25% pure. It is free from an acrosin inhibitor which is located in the spermatozoa. 2. In the hydrolysis of N-alpha-benzoyl-l-arginine ethyl ester the degree of activation of acrosin by Ca(2+), and by some other cations, is dependent on the extent of contamination by the inhibitor. In 50mm-Tris-HCl buffer (pH8.2) activation by Ca(2+) did not exceed 40%, but acrosin that is partially inhibited may be activated by up to 300%: this is due to cation-mediated protection of acrosin against the inhibitor. 3. Increasing concentrations of buffers (e.g. Tris) also activate acrosin but at above certain buffer concentrations Ca(2+) no longer exerts an activating effect and may become inhibitory. Ca(2+) is also inhibitory when added to assay systems involving anionic buffers with chelating properties. This is due to a fall in pH. 4. The above results suggest reasons for conflicting conclusions in papers dealing with the effects of Ca(2+) on acrosin activity. 5. Inhibition of acrosin by the Kunitz pancreatic trypsin inhibitor is increased on addition of Ca(2+). Inhibitions of trypsin by the acrosin inhibitor and by the Kunitz inhibitor are insensitive to Ca(2+). 6. Like trypsin, acrosin is activated, up to 60%, by 2-methyl-propan-2-ol, dimethyl sulphoxide, and some other water-miscible solvents. Effects of cations and solvents tend to be additive and a common maximum acrosin activity can be achieved with various concentrations of solvent, salts and buffer in the assay system. Activation by solvents is increased when low concentrations of the acrosin inhibitor are present. 7. Activations of acrosin by salts and by solvents are more pronounced when the substrate is N-alpha-benzoyl-dl-arginine 2-naphthylamide. 8. K(m) values for ram acrosin (about 0.2mm) are much higher than those for trypsin, and k(cat.) values are slightly higher than those for trypsin. Considerations of the influences of ions and dimethyl sulphoxide on the activities and kinetic constants of acrosin and trypsin suggest that conformational changes are the factors mainly responsible for the reported activations of acrosin. 9. The following conclusions are reached. (a) Acrosin plays a role in the penetration of the sperm cell into the egg without becoming detached from the acrosomal membrane. (b) The enzyme is a peripheral membrane protein which may be classed as a cathepsin. (c) The susceptibility of the activity of soluble acrosin to cations and solvents points to a flexible molecule, i.e. one lacking conformational restraints imposed by association (presumably ionic) with the acrosomal membrane.


The ribosomal ribonucleic acid of Agrobacterium tumefaciens. The 23S rRNA of Agrobacterium tumefaciens contains at least two nicks which result in the formation of RNA components with mol.wts. of 0.52 X 10(6) and 0.48 X 10(6). Thus under the usual conditions of extraction and analysis, no 23S rRNA was recovered from the bacterium. The experiments show that 23S rRNA is synthesized as a continuous chain, in which one or two nicks are formed almost immediately near the ends of the molecule and an additional nick in the middle at a later time.


Structure and biosynthesis of the ribosomal ribonucleic acids from the oncogenic bacterium Agrobacterium tumefaciens. The rRNA of the oncogenic bacterium Agrobacterium tumefaciens was extracted by several methods and analysed by polyacrylamide-gel electrophoresis. The large rRNA of this bacterium is degraded in vivo during the maturation of the ribosome. The influence of Mg2+ and denaturation on degradation of 23S RNA was studied. In pulse and chase experiments, we identified two precursors of the rRNA with mol.wts. of 1.04 x 10(6) and 0.70 x 10(6). From studies of the structure of the large rRNA, we propose that it could have arisen from a gene duplication. This structure is discussed in relation to a recent hypothesis involving such gene duplication as a means of origin of 23S rRNA.


The amino acid sequence of the alpha chain of the major haemoglobin of the rat (Rattus norvegicus). 1. A partial amino acid sequence of the alpha chain from the rat (Wistar, Rattus norvegicus) major haemoglobin is reported. The soluble tryptic peptides prepared from aminoethylated alpha-globin were separated by peptide 'mapping'. Sequencing of the tryptic peptides was carried out by the dansyl-Edman method and by the overlapping of smaller peptide fragments derived from secondary enzymic digestion. The insoluble 'core' peptides were further digested with chymotrypsin, thermolysin and pepsin to give smaller soluble peptides for sequencing. The tryptic peptides were ordered on the basis of their homology with the corresponding peptides of human alpha chain. 2. The proposed sequence is compared with that obtained by using an automated sequencer [Garrick et al. (1975) Biochem. J. 149, 245-258]. The differences in sequence resulting from the two methods are discussed. 3. It is suggested that the externally situated cysteine (residue 13) is responsible for the observed inhibition of crystallization of rat haemoglobin at alkaline pH. 4. Detailed evidence for the sequence has been deposited as Supplementary Publication SUP 50047 (9 pages) at the British Library (Linding Division), Boston Spa, Wetherby, West Yorkshire LS23 7BQ, U.K., from which copies can be obtained on the terms given in Biochem. J. (1975) 145, 5.


The amino acid sequence of cytochrome f from the brown alga Alaria esculenta (L.) Grev. Cytochrome f was isolated from the brown alga Alaria esculenta and the amino acid sequence was determined. The native haemoprotein has a molecular weight of 9800 and consists of a single polypeptide chain of 86 amino acid residues with a haem group bonded to cysteine residues at positions 14 and 17. The N-terminus is not acetylated and no methylated lysines were found. Sequences of three other algal cytochromes f were compared with that of Alaria and 22 out of 92 positions were common to the four sequences. One-half of these conserved sites occur between positions 49 and 63. Detailed evidence for the amino acid sequence of Alaria cytochrome has been deposited as Supplementary Publication SUP 50048 (6 pages) at the British Library (Lending Division), Boston Spa, Wetherby, West Yorkshire LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1975) 145, 5.


Evidence against the proposed interaction of thionitrobenzoate with protein disulphide bonds. Thionitrobenzoate was prepared from 5,5'-dithiobis-(2-nitrobenzoic acid), and its reaction with several disulphide-containing proteins was examined under various conditions. No evidence for any cleavage of disulphide bonds was obtained. The claim by Robyt et al. [Arch. Biochem. Biophys. (1971) 147, 262-269] that thionitrobenzoate allows the quantitative determination of disulphide bonds in proteins is not substantiated.


The photocarcinogenicity of anthracence: photochemical binding to deoxyribonucleic acid in tissue culture. Anthracene becomes covalently bound to high-molecular-weight DNA in mammalian tissue culture as a result of irradiation at 365 nm after the incubation of cells with the hydrocarbon. At high radiation doses, the extent of binding exceeds one hydrocarbon molecule per 10(3) bases, and is lethal. At low radiation doses, much decreased binding is observed, but a majority of cells remain viable and can be recultured.


The effect of some amine oxides and disulphide compounds on the activity of acetylcholinesterase. Three amine oxides, two aliphatic and one aromatic, and 2,2'-dithiodipyridine were found to be weak reversible inhibitors of acetylcholinesterase. 5,5'-Dithiobis-(2-nitro-benzoic acid) had no effect on the enzyme under the conditions of the Ellman spectrophotometric assay.


Effects of adenine nucleotides on rice-root adenosine triphosphate sulphurylase activity in vitro. The presence of ATP sulphurylase activity in the 30000g supernatant fraction of rice-root homogenate has been demonstrated. Studies of the effects of adenosine and its nucleotides on the enzymic activity showed that AMP activated but that ADP and adenosine inhibited the enzyme.


The complexity of satellite deoxyribonucleic acid in a higher plant. Purified satellite DNA from melon (Cucumis melo) was shown to contain at least two components from thermal-denaturation and renaturation studies. Two components were separated after partial renaturation, a fast-renaturing fraction similar in complexity to mouse satellite DNA, and one with 6000 times greater complexity. Both components renatured very accurately, indicating a minimum of sequence divergence. Centrifugation of the purified satellite DNA in Ag+/Cs2SO4 gradients resolved two major and several minor fractions. The two major fractions were only slightly enriched for fast- or slow-renaturing sequences.


The extraction and characterization of bovine epidermal alpha-keratin. 1. The alpha-fibrous protein (alpha-keratin) component of bovine epidermis has been extracted and characterized. 2. Prekeratin, a multichain unit of the epidermal tonofilaments, was shown to consist of six different polypeptide chains on polyacrylamide-gel systems containing sodium dodecyl sulphate or sodium decyl sulphate with discontinuous gel buffers, but only three chains were seen when a gel system containing sodium dodecyl sulphate with a continuous gel buffer was used. 3. Extraction of the 'keratinized' stratum corneum and the living part of the epidermis with urea buffers at pH 7.6 or 9.0 released 60% of the total dry weight of the tissues in the form of alpha-helical polypeptides. 4. The numbers, relative amounts and properties of the extracted polypeptides were the same as the subunits of prekeratin and thus are derived from the tonofilaments in situ. 5. The subunits of prekeratin and the polypeptides extracted from the living cell layers contained an average of six cysteine residues, but those from the stratum corneum contained an average of three intrachain disulphide bonds. 6. The polypeptide chains aggregated through non-covalent interactions in vitro into filaments that were similar to the tonofilaments. 7. Since the polypeptides could be released from the stratum corneum without breaking covalent bonds, it is concluded that such bonds do not cross-link the tonofilaments and non-fibrous keratohyalin. It is suggested that the tonofilaments and keratohyalin of bovine epidermis are associated by secondary bonding forces.


Microbial L-phenylalanine ammonia-lyase. Purification, subunit  structure and kinetic properties of the enzyme from Rhizoctonia solani. 1. Phenylalanine ammonia-lyase (EC 4.3.1.5) was purified to homogeneity from the acetone-dried powders of the mycelial felts of the plant pathogenic fungus Rhizoctonia solani. 2. A useful modification in protamine sulphate treatment to get substantial purification of the enzyme in a single-step is described. 3. The purified enzyme shows bisubstrate activity towards L-phenylalanine and L-tyrosine. 4.  It is sensitive to carbonyl reagents and the inhibition is not reversed by gel filtration. 5. The molecular weight of the enzyme as determined by Sephadex G-200 chromatography and sucrose-density-gradient centrifugation is around 330000. 6. The enzyme is made up of two pairs of unidentical subunits, with a molecular weight of 70000 (alpha) and 90000 (beta) respectively. 7. Studies on initial velocity versus substrate concentration have shown significant deviations from Michaelis-Menten kinetics. 8. The double-reciprocal plots are biphasic (concave downwards) and Hofstee plots show a curvilinear pattern. 9. The apparent Km value increases from 0.18 mM to as high as 5.0 mM with the increase in the concentration of the substrate and during this process the Vmax, increases by 2-2.5-fold. 10. The value of Hill coefficient is 0.5. 11. Steady-state rates of phenylalanine ammonia-lyase reaction in the presence of inhibitors like D-phenylalanine, cinnamic, p-coumaric, caffeic, dihydrocaffeic and phenylpyruvic acid have shown that only one molecule of each type of inhibitor binds to a molecule of the enzyme. These observations suggest the involvement of negative homotropic interactions in phenylalanine ammonia-lyase. 12. The enzyme could not be desensitized by treatment with HgCl2, p-chloromercuribenzoic acid or by repeated freezing and thawing.


Regulatory effects of fatty acyl-coenzyme A derivatives on phosphate-activated pig brain and kidney glutaminase in vitro. 1. Fatty n-acyl-CoA derivatives in the concentration range 5muM-0.1mM and with 5-18 fatty acyl carbons have dual effects on phosphate-activated glutaminase from pig brain and kidney. Generally, fatty acyl-CoA derivatives in low concentrations activate the enzyme, but inhibit at higher concentrations; phosphate and citrate potentiate the activation, displaying positive co-operatively, and protect against inactivation. The fatty acyl-CoA derivatives affect glutaminase similarly to Bromothymol Blue, but differently from acetyl-CoA, which activates the enzyme only at very low phosphate or citrate concentrations. 2. Saturated fatty acyl-CoA derivatives, with 5-10 fatty acyl carbons, only activate the enzyme in the concentration range 0-0.1 mM. When the fatty acyl chain is elongated, the fatty acyl-CoA derivatives gradually become more powerful inhibitors of glutaminase at the expense of their activating capacity. In particular, palmitoyl-CoA and stearoyl-CoA are strong inhibitors at concentrations (10 muM) at which the corresponding free fatty acids and fatty acyl-carnitine derivatives have no effect. 3. The unsaturated fatty acyl-CoA derivatives, oleoyl-CoA and linoleoyl-CoA, behave as potent activators in the lower part of the concentration range tested (0-0.05mM), and as inhibitors in the upper part of this range (0.02-0.10mM). Oleic acid and linoleic acid have similar properties, but their activating capacity is less pronounced. 4. Phosphate both prevented and reversed the inhibition, but no restoration of activity was possible once the enzyme became inactivated. 5. By changing the pH from 7.0 to 8.0 the activating capacity of the fatty acyl-CoA derivatives is increased, as is their concentration range for activation. 6. The fatty acyl-CoA derivatives are somewhat more potent activator for brain glutaminase, but otherwise they affect the two enzymes similarly.


Studies on the infectious etiology of human rheumatoid arthritis. II. Search for humoral and cell-bound antibodies against mycoplasmal antigens. A total of 29 rheumatoid patients and 19 nonrheumatoid patients were tested for evidence of present or past infection by M pneumoniae, M hominis, M fermentans, M arthritidis, M pulmonis, and M hyorhinis. The techniques of lymphocye transformation, metabolic-inhibiting antibody test, and mycoplasmcidal antibody test indicated no significant difference in the response of rheumatoid as opposed to nonrheumatoid patients.


Freeze-etch study of collagen. I. Native collagen from tendon and lung of rats. The freeze-fracture technique was used to study the fine structure of native collagen from rat tendon and lung. The collagen filaments were organized into a spiraled lamellar substructure within each fibril. Small particles, representing the broken ends of the collagen filaments, were found in nearly straight rows when the lamellae were broken tranversely. Filamentous connections were shown which span the interfibrillar matrix and unite all of the fibrils into a reticular network. The fibrils were coated with material that was greatly hydrated in vivo. Sublimation occurred more rapidly from some portions of the coating substance than from others, resulting in a banding pattern with a 610 A repeat distance.


Electron microscopic studies of the cartilage-pannus junction in rheumatoid arthritis. The junction between pannus and cartilage was examined in the rheumatoid joint. Three types of cartilage-pannus junction were observed. In one, proliferating small blood vessels, surrounded by highly cellular infiltrates, penetrated deeply into the cartilage. Degeneration of the cartilage was observed around the cellular accumulations. In the second, phagocytic and fibroblastic cells invaded the cartilage. In the third, fibrous pannus overlay the cartilage. Lysis of cartilage by infiltrating cells appeared to be a major cause of cartilage erosion in rheumatoid arthritis.


Changes in the lipids of human articular cartilage with age. Histochemical and chemical studies demonstrated a significant increase in the lipods of articular cartilage with advancing age. Triglycerides, cholesterol, and phospholipids were identified chemically and were shown by comparative staining procedures to be present in intracellular and extracellular lipids. The distribution and the composition of the extracellular lipids were interpreted as indicating that the extracellular lipids are of cellular origin. Glycolipids were extracted from cartilage of all ages and were shown to account for a portion of the increase in total lipid with age. Glycolipids extracted from aged cartilage were partially characterized. Cerebrosides, sulfatides, and gangliosides were detected. Glycolipids were estimated to comprise from 5 to 10% of the total lipid of articular cartilage. Arachidonic acid concentrations increased maredly with age in the surface of cartilage but were present in trace amounts in deep cartilage, demonstrating clear-cut differences in the levels as well as the location of this fatty acid precursor of the prostaglandins (PGE2 and PGF2alpha).


Wegener's granulomatosis. Long-term followup of patients treated with cyclophosphamide. Ten patients with Wegener's granulomatosis were treated with cyclophosphamide and followed for periods up to 7 years. In all cases cyclophosphamide induced complete remissions. The mean duration of remission (to date) was 38 months. Six patients have been in remission for a mean of 46 months after cyclophosphamide was discontinued; 2 have been disease-free for 7 years. Of the 10 patients treated, only 1 relapsed and she responded to a second course of cyclophosphamide. These results indicate that cyclophosphamide is the drug of choice in Wegener's granulomatosis. The long-term effectiveness of this drug suggests that it may induce permanent remissions in certain patients with Wegener's granulomatosis.


Bone resorption of the mandible in progressive systemic sclerosis. Five of 16 patients with progressive systemic sclerosis were found to have bone resorption at the angle of the mandible. This finding appears to be closely related to the tightness of the skin of the face, atrophy of the masseter and pterygoid muscles, small size of the oral orifice, and a significantly high frequency in blacks. The mandible must therefore be added to the list of those bones that can be resorbed in progressive systemic sclerosis.


Effect of topical administration of antiinflammatory drugs to rats with adjuvant arthritis. Oral or intramuscular administration of antiinflammatory agents produces numerous undesirable side effects. This work explores the hypothesis that topical administration of such agents directly to the site of inflammation would have beneficial antiinflammatory effects. Topical administration of steroidal and nonsteroidal antiinflammatory drugs to rats with adjuvant arthritis was as effective as oral or intramuscular administration. Peak blood levels of radioactivity following administration of equal doses of hydrocortisone-3H were considerably lower after topical administration than after oral administration.


Spontaneous remission of Felty's syndrome. The clinical course of a patient with Felty's syndrome is described. This patient was unusual because during a 3-year period of splenomegaly and leukopenia she did not develop repeated infections, leg ulcers, or other complications of Felty's syndrome. Then a spontaneous remission began. During the subsequent 6 years, neither symptoms nor signs of Felty's syndrome have recurred.


The effect of carbon monoxide on lipid metabolism of human coronary arteries. Human coronary arteries were perfused under sterile conditions in vitro with blood containing high or low concentrations of carbon monoxide. Lipid synthesis in the arterial wall was investigated by incorporating [14C]acetate; synthesis of the following lipids was measured: cholesterol, cholesterol ester, di- and triglycerides and phospholipids. Cholesterol uptake by the arterial wall was studied by using [3H]cholesterol as a tracer. No influence of CO on lipid synthesis in the arterial wall could be demonstrated. In contrast, arteries which were exposed to CO showed a higher uptake of cholesterol as compared to their corresponding control. The concentration of CO in the perfusate did not alter the degree of cholesterol uptake. These results are in general agreement with those of others, who found that CO significantly increases the permeability of endothelial membranes.


Homocysteine theory of arteriosclerosis. Arteriosclerotic plaques were found in the aorta and arteries of rabbits given homocysteine thiolactone, methionine or homocysteic acid, both parenterally and in a synthetic diet. Animals given large doses of parenteral methionine or homocysteine thiolactone died of pulmonary embolism and pulmonary infarct. Pyridoxine prevented thrombosis and pulmonary embolism but did not prevent arteriosclerotic plaques. These findings and previous work, showing a new matabolic pathway for sulfate ester synthesis from methionine, the somatotrophic activity of homocysteic acid, and control of cellular growth and intercellular matrix synthesis by homocysteine derivatives, suggest a theory to explain aspects of the pathogenesis of arteriosclerosis.


Exchange of plasma radioactive cholesterol with atheroma lipids in situ and implanted subcutaneously. Physicochemical exchange of radioactive cholesterol was investigated in mildly hypercholesterolaemic rabbits. Such exchange was examined in erythrocytes and atheroma lipids in situ in the aortic wall and in such lipids when implanted subcutaneously. The implanted atheroma lipids gained radioactivity from intravenously injected [3H]cholesterol, even though cholesterol was being resorbed from the implants. Autoradiography showed exchange between plasma cholesterol and both intracellular and dispersed extracellular lipid in these implants. Cholesterol crystals in both implants and atheromatous lesions labelled only sluggishly. The results are consistent with the view that physicochemical exchange is a major factor in cholesterol movement in vivo.


Aortic hexosamine, [35S]sulfate uptake, and calcium metabolism related to early arterial degenerative changes induced by lactation and forced weaning in breeder rats. The relation of lactation and weaning to the development of early arterial lesions in the female breeder rat was investigated. Changes in aortic hexosamine and 35S-uptake, which are indicative of ground substance metabolism were correlated with changes in aortic calcium, phosphorus, and 45Ca-uptake during lactation and weaning. Lactation was associated with reduced aortic hexosamine content and lowered uptake of [S]sulfate. Further dynamic changes in aortic metabolism of these substances occurred following weaning in conjunction with an intense calcium uptake in the aorta of some, but not all, of the post-lactation animals. These latter changes were associated with the beginning aortic calcifications. Histopathologically, early arterial lesions developing during lactation, consist of intimal accumulations of mucopolysaccharide capped over by collagen. With repeated breeding cycles, these early lesions become exacerbated with extensive medial calcification occurring in areas rich in mucopolysaccharide and collagen particularly around degenerating elastic fibers. The hormones associated with reproduction and lactation may have a conditioning effect on these arterial connective tissue alterations and the development of arterial degenerative changes.


Effect of electrical stimulation on the tensile strength of the porous implant and bone interface. The effect of electrical stimulation upon the direct tensile strength of the interfacial union between porous calcium aluminate implants (100 to 200 mu diameter pores) and bone was studied in the femurs of rabbits. After about 4 weeks of implantation the tnesile strength of the electrically stimulated specimens was approximately two times that of the nonstimulated ones. This indicates that electrical stimulation increased the rate of new bone formation under the experimental conditions.


In vivo chemotaxis of rat leukocytes in the presence of circulating chylomicrons. Dietary-induced chylomicronemia was produced in rats to determine its effect on the chemotactic activity of 51Cr-labelled adoptively transferred isologous leukocytes. Rats fed a low protein high fat diet for 2 months had normal total plasma cholesterol and triglyceride levels, but increased amounts of chylomicrons. Circulating neutrophils and monocytes from animals on a normal diet were able to phagocytose chylomicrons from plasma of those animals on the special diet. Peritoneal exudate cells from the latter animals contained intracellular chylomicrons demonstratable both histologically and biochemically. Neutrophils and mononuclear cells from normal or special fed animals, when transferred to chylomicronemic recipients, had a reduced ability to accumulate at the site of a complement-dependent inflammatory reaction but circulated normally. The defective chemotactic activity observed could be duplicated when cells were allowed to ingest aggregated protein instead of chylomicrons. It was concluded that circulating leukocytes ingest chylomicrons from the plasma with a resultant reduction in their chemotactic activity. The results were discussed in relation to the increased incidence of infection in diabetes characterized by Type I and V hyperlipidemias. It was also suggested that phagocytosis of particulate substances by entrapped leukocytes in atherosclerotic lesions would induce phagocytic enzyme release which could contribute to the eventual destruction of the vascular wall.


The arterial acyl-CoA:cholesterol acyltransferase and cholesterol ester hydrolase activities. Cholesterol acyltransferase and cholesterol esterase activities of protein extracts from pig aortas have been examined and the rations of synthesis/hydrolysis rates in the presence of substrates with different fatty acids estimated. The values obtained were in the numerical order: cholesteryl oleate greater than palmitate greater than or equal to linoleate greater than linolenate greater than staerate. The results are discussed in relation to the known different accumulation of cholesterol esters in the arterial wall.


Primary hyperlipoproteinemias as risk factors in peripheral artery disease documented by arteriography. In a controlled study on 121 patients with peripheral vascular disease (PVD) (75 patients with primary hyperlipoproteinemia, 15 diabetics, 31 patients without metabolic disease) the relationship between risk factors (hyperlipoproteinemia, obesity, hypertension, abnormal glucose tolerance, smoking) and the degree and localisation of sclerotic lesions was investigated by angiography. The degree was directly related in all patients to the number of risk factors, in Type IIa to cholesterol levels, in diabetics and Type IV with abnormal glucose tolerance to age. The latter patients were 5-10 years older than patients with Type IIa and showed 2 or more additional risk factors. The sclerotic lesions affected in Type IIa, less in Type IIb, predominately the pelvic vessels. Diabetics and Type IV patients showed a distal arterial involvement. The difference was significant. The degree of sclerotic lesions in arteries of the pelvis and the distal lower limb was positively correlated with the cholesterol-triglyceride ratio. Smoking aggravated the pelvic lesions in Type IV. Hypertension lead to more pronounced lesions of the distal lower limb in Type II. S-shaped tortuosities of the big vessels were shown to be typical, independent of localisation or degree.


The effect of external drainage of bile on cholesterolemia. The cholesterolopenic phenomenon--decrease of up to 30% for total cholesterol and up to 23% for esterified cholesterol--has been obtained as an effect of external drainage of bile from the common biliary duct.


A study of the lecithin/sphingomyelin ratio of amniotic fluid. 1. There is a significant correlation between lecithin/sphingomyelin (L/S) ratios based on densitometry (L/S)D and L/S ratios based on phosphorus determinations ((L/S)P). 2. The fetal lung is mature when the (L/S)D, determined according to Verhoeven, A.G.J. and Merkus, H.M.W.M. (1974) Clin. Chim. Acta 53, 229--232, is 1.2. This value is equivalent to an (L/S)P of 1.8. 3. The acetone precipitation procedure, introduced by Gluck, L., Kulovich, M.V., Borer, R.C. and Keidel, W.N. (1974) Am. J. Obstet. Gynecol. 120, 142--155, is a necessary step for isolating surface-active lecithin. 4. Standardization of the (L/S)D test is feasible and should permit different laboratories to use the same transition point.


Removal of plasma cholesterol by adsorption chromatography. Batch and column chromatography with porous glass decreased the plasma concentration of cholesterol. Extracorporeal circulation of blood through a column filled with porous glass, as well as exchange transfusion with blood made hypocholesterolemic by passage of its plasma through a column filled with porous glass, temporarily reduced plasma cholesterol concentration in rats.


Observations on the antibody-dependent cytotoxic cell by scanning electron microscopy. The cytotoxic effect of human peripheral blood leucocytes on antibody-coated sheep erythrocyte monolayers has been investigated using scanning electron microscopy. Only a small proportion of leucocytes were found to adhere to the monolayers. A progressive destruction was observed beginning as small plaque-like areas of erythrocyte clearing which later became confluent. Three distinct cell types were found to be associated with the areas of lysis. No destruction was observed in control monolayers incubated for a similar period in the absence of either antibody of leucocytes. Surface changes in the erthrocytes adjacent to the leucocytes suggest that mechanical factors may be involved in erythrocyte lysis in this system. It is concluded that more than one leucocyte type may damage antibody-coated erythrocytes, possibly by a mechanism involving attachment to and mechanical disruption of the red cell membrane.


Serum-mediated immunoresponses to spermatozoa. Sixty male Lewis rats were immunized in groups of 10 by: (i) conventional vasectomy with ligation of the vas deferens; (ii) vasectomy without ligation of the vas deferens; (iii) sham vasectomy (control); (iv) subcutaneous injection of 10(9) allogeneic spermatozoa (from inbred BN rats) in complete Freund's adjuvant (CFA); (v) subcutaneous injection of 10(9) syngeneic spermatoza in CFA; (vi) subcutaneous injection of 10(9) syngeneic spleen cells in CFA (control). One in vivo and one in vitro assay for serum-mediated immunity were performed for each group of rats. The assays were: (i) 3-hr footpad swelling response to the injection of spermatozoa or spleen lymphocytes (Arthus response); and (ii) release of radioactivity from 51Cr-labeled spermatozoa or lymph node cells (cytotoxic antibody). A serum-mediated immunoresponsiveness specific to spermatozoa was observed in all experimental groups, except rats vasectomized without ligation of the vas deferens. Since the rats vasectomized by different methods bore similar size sperm granulomas, a pathologic explanation for the variance in immune response is not apparent. The specificity of the serum response to allogeneic (BN) spermatozoa in rats immunized with allogeneic spermatozoa is surprising, because spermatozoa probably carry histocompatibility antigens. Possible explanations for the patterns of immunoresponsiveness to spermatozoa are discussed.


Sodium kinetics in aorta of spontaneously hypertensive rats. Transport rate constants (kij) for Na exchanges in isolated aorta of normotensive and spontaneously hypertensive rats (SHR) were determined with the use of 33Na as a tracer and the aid of digital computer simulation. A three-compartment model consisting of 1) extracellular, 2) intracellular, and 3) "endointracellular" spaces (compartments) was found to describe adequately the kinetics of 22Na. Results show that in SHR: I) K01, which is related to the overall Na outflow from tissue, was increased by 41%; ii) k12, describing Na movements from intra- to extracellular compartment, was increased by 67%; iii) k21, representative of Na movements from extra-to intracellular compartment, was decreased by 39%. These results indicate a faster turn-over of Na and a relative accumulation or translocation of Na into the extracellular space in aorta of SHR. The findings are interpreted in the light of recent reports on the role of Na in contractile response or reactivity of arteries. A humoral mechanism operative at the arterial wall level for the development of hypertension is at the arterial wall level for the development of hypertension is suggested. The main significance of the methodology employed in this work is that the values found for the kij are not subject to fluctuations intrinsic to auxiliary indicators of extracellular space.


[Some characteristics of the biological action of D, L-1,4-dibromo-1,4-dideoxy-2,3-butanediol]. In tests conducted on mice and rats with transplantable tumours the antineoplastic activity of the racemic agent D, L-1,4-dibromo-1, 4-didesoxy-2, 3-butandiol is shown. With chronic administration of the drug in subtherapeutic and therapeutic doses a higher leucocytes count was in evidence in the blood of the animals with and without tumours.


Different organization of cat lateral geniculate neurons in binocular inhibitory interaction. The principal cells of the geniculate nucleus are generally classified into two types in terms of their anatomical connection with the optic nerve fibers; the contralateral geniculate cell on which the contralateral optic nerve fibers make excitatory synapses and the homolateral geniculate cell on which homolateral optic nerve fibers synapse. In the present experiments, the organization of binocular inhibition in the two different types of geniculate cells was investigated in the cats anesthetized with a chloralose-urethane mixture. In homolateral geniculate cells, an action spike produced by a volley in the ipsilateral optic nerve was often suppressed by a conditioning volley in the contralateral optic nerve (binocular inhibition). In the contralateral geniculate neurons, a conditioning volley in the homolateral optic nerve only occasionally inhibited the generation of an action spike produced by a contralateral optic nerve volley. Intracellular recording from the geniculate cells confirmed the results obtained by extracellular studies. It was concluded that binocular interaction at the lateral geniculate level was seen more commonly in the homolateral geniculate cells than in the contralateral cells.


[Intercellular contacts and the synchronization of fluctuations in the dry weight of glial cells]. The change of rhythmic dry mass fluctuations of the cultured glial cell due to its exposure to ultra-violet rays (the wave length 280-370 nm) produces similar changes in the contacting non-irradiated cell. The data obtained show that the intercellular contact has an important role in the synchronization of glial cell dry mass fluctuations.


Changes in labeling of soluble and solubilized rat brain proteins using (3H)-leucine as precursor during a learning experiment. This paper deals with an electrophoretic study on soluble and solubilized rat brain proteins during a brightness discrimination. After intraventricular injection of L-[3H]-leucine the most pronounced increase in relative specific activity was found for several soluble acidic protein-band complexes as well as for solubilized slow-migrating non-myelin proteins obtained from hippocampus of trained animals over the data obtained for active and passive controls.


Effect of different glycerol levels on the release of glutamic oxaloacetic transaminase (GOT) from deep frozen ram spermatozoa. Release of GOT was determined during different treatments in ram semen extended (1:10) with lactose-egg yolk diluter containing 3.5% and 5% glycerol (v/v). Semen samples were collected by the electro-ejaculation technique and GOT was analysed colorimetrically. Highly significant difference (p less than 0.01) was found in the post-thaw percent motile spermatozoa and GOT release (IU/10(9) spermatozoa) between 3.5% and 5% glycerol containing equilibrated samples. The difference in percent motile spermatozoa was not significant between 3.5% and 5% glycerol levels in control, post-thaw unequilibrated and prefreeze equilibrated samples. Whereas the difference in GOT release between 3.5% and 5% glycerol concentrations was not significant in control and post-thaw unequilibrated samples and highly significant (p less than 0.01) in prefreeze equilibrated samples.


Ocular tissue absorption of clindamycin phosphate. Clindamycin phosphate, a new semisynthetic antibiotic that is effective in the treatment of toxoplasmosis and of infections caused by Gram-positive bacteria, was found to be highly concentrated in the choroid, iris, and retina of the pigmented rabbit eye after a single intramuscular injection of 75 mg/kg. Drug levels considered adequate for the control of most ocular infections were detectable in the iris, choroid, and retina 24 hours after injection, at which time serum levels were negligible. Subconjunctival injection of clindamycin phosphate also produced sustained high levels of drug in the choroid, iris, and retina; but when 150 mg was injected in a volume of 1 ml, corneal edema and severe inflammation of the conjunctiva resulted. Lesser amounts (15 to 35 mg) injected subconjunctivally produced adequate ocular tissue levels without damage to the conjunctiva or cornea.


Quantitative structural analysis of pulmonary vessels in isolated ventricular septal defect in infancy. Structural changes in the pulmonary circulation were studied in the lungs of 5 infants dying with ventricular septal defect. Applying precise quantitative morphological techniques to the pulmonary vessels, it was possible to correlate pathological change with clinical and haemodynamic findings, and to identify two patterns of response. Three of the infants (group I) ppresnted in cardiac failure with a large pulmonary blood flow, dilated and tortuous pulmonary arteries, and fewer intra-acinar vessels than normal. Medial hypertrophy was moderate and affected chiefly the larger arteries, i.e. those with a diameter greater than 200 mum. The other 2 infants (group 2) had a high pulmonary vascular resistance with an intermittent right-to-left shunt. The pulmonary arteries were of normal size and the reduction in the number of the arteries was less striking. Medial hypertrophy was greater than in the first group and affected all sizes of artery including those less than 200 mum in diameter. In both groups, muscle extended further along the axial pathway. Muscular hypertrophy was found also in the vein wall in most cases and, as with the arteries, was more severe in those with a higher pulmonary vascular resistance. The findings illustrate the variation in pulmonary vascular response in infants with a ventricular septal defect. It is suggested that in patients with a ventricular septal defect, arterial muscularity usually regresses after birth and a left-to-right shunt develops; secondary hypertrophy of the media then develops in reaponse to the shunt. Our findings also suggest, however, that in some infants arterial muscle fails to regress postnatally so that pulmonary blood flow is never high and a right-to-left shunt develops soon after birth.


Effect of chronic beta-adrenergic receptor blockade in congestive cardiomyopathy. Adrenergic beta-blocking agents were given to 7 patients with advanced congestive cardiomyopathy who had tachycardia at rest (98 plus or minus 13 beats/min). The patients were on beta-adrenergic receptor blockade for 2 to 12 months (average 5-4 months). One patient was given alprenolol 50 mg twice daily and the other patients were given practolol 50 to 400 mg twice daily. Virus infection had occurred in 6 of the patients before the onset of symptoms of cardiac disease. All patients were in a steady state or were progressively deteriorating at the start of beta-adrenergic receptor blockade. Conventional treatment with digitalis and diuretics was unaltered or reduced during treatment with beta-blocking agents. An improvement was seen in their clinical condition shortly after administration of the drugs. Continued treatment resulted in an increase in physical working capacity and a reduction of heart size. Noninvasive investigations including phonocardiogram, carotid pulse curve, apex cardiogram, and echocardiogram showed improved ventricular function in all cases. The present study indicates that adrenergic beta-blocking agents can improve heart function in at lease some patients with congestive cardiomyopathy. Furthermore, it is suggested that increased catecholamine activity may be an important factor for the development of this disease, as has been shown in animal experiments.


131Cs myocardial scintigraphy. Application to assessment of anterior myocardial infarction. Earlier studies have indicated that caesium-131 is a good myocardial scanning agent for the demonstration of anterior infarcts. One hundred and ten patients with documented anterior myocardial infarction were studied by 131Cs myocardial scintigraphy. An anterior area of decreased uptake of caesium was noted in all but 3 subjects whose necrotic zone was likely to be of small dimensions. In 20 cases, the scintigram showed a definite, sometimes very large, cold area whereas the electrocardiogram failed to display any diagnostic feature of myocardial necrosis. In most of the latter instances, the electrocardiographic diagnosis was obscured by the presence of intraventricular conduction disturbances. In order to visualize the intracardiac cavities, the 131Cs investigation was usually completed by a 113mIn scintigram, which allowed recognition of a parietal aneurysm in 12 of the 18 patients with extensive anterior lesions. In each case, an index of necrosis was computed from planimetric measurements of the infarcted area as compared to the total left ventricular surfact in both the anteroposterior and left anterior oblique projections. This index was shown to correlate with the incidence of major complications developing after the acute episode of coronary occlusion. The sensitivity, specificity, and accuracy of the method are briefly discussed. It is felt that myocardial scintigraphy represents a sound approach to the semiquantitative assessment of anterior myocardial infarction; the clinical usefulness of the technique seems sufficiently demonstrated to prompt further research in this field.


Echocardiography of the intra-aortic balloon. Echocardiography was performed on 9 patients being treated for cardiogenic shock with an intra-aortic balloon. The value of simultaneous recording of the electrocardiogram, cardiac movements, and arterial pressure, with the echocardiogram of the intra-aortic balloon is discussed. The results indicate that echocardiography provides a method of studying intra-aortic balloon function.


Comparison of Triosil 370 with Urografin 76 and Hypaque 65 for coronary arteriography. Triosil 370 has been compared with Urografin 76, and Hypaque 65 by injecting identical volumes into the coronary arteries of human subjects in the course of coronary arteriography. The injection times used were the same and neither the patient nor the coronary artery catheter were moved between injections. The order in which the solutions compared were injected was alternated. The deviation in the ST segment and of the T wave which resulted from the injection was measured. The Triosil caused significantly less change than Urografin and Hypaque. A numerical expression of the T wave deflection derived from the data showed Triosil:Hypaque:Urografin equals I:2.6:2.9.


Dual atrioventricular nodal pathways. A common electrophysiological response. Evidence of dual atrioventricular nodal pathwats (a sudden jump in H1-H2 at critical A1-A2 coupling intervals) was shown in 41 out of 397 patients studied with atrial extrastimulus techniques. In 27 of these 41, dual pathways were demonstrable during sinus rhythm, or at a cycle length close to sinus rhythm (CL1). In the remaining 14, dual pathways were only demonstrated at a shorter cycle length (CL2). All patients with dual pathways at cycle length who were also tested at cycle length (11 patients) had dual pathways demonstrable at both cycle lengths. In these 11 patients both fast and slow pathway effective refractory periods increased with decrease in cycle length. Twenth-two of the patients (54%) had either an aetiological factor strongly associated with atrioventricular nodal dysfunction or one or more abnormalities suggesting depressed atrioventricular nodal function. Dvaluation of fast pathway properties suggested that this pathway was intranodal. Seventeen of the patients had previously documented paroxysmal supraventricular tachycardia (group 1). Eight patients had recurrent palpitation without documented paroxysmal supraventricular tachycardia (group 2), and 16 patients had neither palpitation nor paroxysmal supraventricular tachycardia (group 3). Echo zones were demonstrated in 15 patients (88%) in group 1, no patients in group 2, and 2 patients (13%) in group 3.


Association of secundum atrial septal defect with abnormalities of atrioventricular conduction or left axis deviation. Genetic study of 10 families. A genetic analysis was made of 10 families in which the propositi had a secundum atrial septal defect associated with abnormal atrioventricular conduction (first, second, or third degree heart block) or unexplained left axis deviation or a combination of these conduction disturbances. Diagnostic information was available on 51 (81%) of the first degree relatives. Three of the families appeared to be examples of a new syndrome which, with variable expression, was inherited as a non-sex-linked autosomal dominant. The main features were a secundum atrial septal defect; disease of the conducting tissue, which in some cases was progressive; unexplained left axis deviation; and unexpected death. These families did not seem to be examples of the Holt-Oram syndrome, for the upper limbs were clinically and radiologically normal in the 19 members examined. The importance of recognizing this syndrome is the occurrence of progressive disease of the conducting tissue and the risk of sudden death. When, therefore, unexplained left axis deviation or prolonged atrioventricular conduction is found in association with a secundum atrial septal defect all available relatives should be examined. In the remaining seven families there was only one affected first degree relative out of 39 examined. He was the son of one of the propositi and had paroxysmal coronary sinus rhythm with an intact atrial septum.


Infradiaphragmatic total anomalous pulmonary venous return. Diagnosis and surgical repair in a 10-year-old child. A unique case of infradiaphragmatic total anomalous pulmonary venous return in a 10-year-old girl is described. A persistent ductus arteriosus, ventricular septal defect, and large atrial septal defect were also present. Corrective surgery was performed at 10 years of age, with an excellent clinical result. The factors which permitted this unprecedented period of survival included non-obstructed drainage of the pulmonary venous blood into the inferior vena cava and a large atrial septal defect.


Atrioventricular block secondary to a congenital aneurysm of the membranous septum. Histological examination of conduction system. Atrioventricular block which caused death in a 6-month-old baby is reported. Necropsy examination revealed the only abnormality in the heart to be an aneurysm of the membranous septum. Histological examination of the conduction system showed fibrosis and attenuation of the bundle of His at the lower border of the aneurysm.


Anatomically corrected malposition of great arteries. Four anomalous hearts are described in which the great arteries arise in unusual fashion from their morphologically appropriate ventricles. This malformation, previously termed anatomically corrected transposition, is now termed anatomically corrected malposition. This is because, following the precedent of Van Praagh and his associates, we now reserve the term 'transposition' to describe the situation in which both great arteries arise from separate morphologically inappropriate ventricles. All the hearts examined exhibited atrioventricular concordance, I with viscero-atrial situs inversus, and 3 with situs solitus. However, there were considerable variations in ventricular morphology between the cases. Thus, 2 cases exhibited atresia of the right atrioventricular valve, and in the remaining 2 cases right and levt ventricular sinuses were both identified. Two of the cases also had pulmonary atresia, and coronary artery anomalies were present in all 4. The cases emphasize the fact that the term anatomically corrected malposition describes not a discrete anomaly but only a ventriculo-arterial relation, which is one of ventriculo-arterial concordance. Doubt has previously been cast upon the existence of this as an anatomical entity. It is concluded that the relation does indeed exist, and furthermore can coexist with all varieties of atrioventricular relations. It is suggested that the differing atrioventricular relations can be distinguished by usage of the terms 'concordant' or 'discordant' anatomically corrected malposition. Finally, it is emphasized that it is necessary to distinguish this anomaly, which in most cases presents with left-sided anterior aorta, from the left-sided anterior aorta more frequently encountered in classically corrected transposition'.


Problems with radical corrective surgery after ascending aorta to right pulmonary artery shunt (Waterston's anastomosis) for cyanotic congenital heart disease. Forty-five patients with Fallot's tetralogy or pulmonary atresia had total correction 2 to 6 years after palliative ascending aorta to right pulmonary artery anastomosis (Waterston's shunt). The operative mortality for total correction is increased in this group. Patients shown subsequently to have had a good anatomical correction died unexpectedly with high central pulmonary artery pressure, falling arterial PO2, low cardiac output, and progressive acidosis. The cause of this syndrome was difficult to determine. Histological examination of the lungs showed that severe pulmonary arteriolar thickening was not present. The factors apparently predisposing to these postoperative difficulties were kinking of the right pulmonary artery and/or lone perfusion of the right lung, remaining uncorrected for several years, in patients with pulmonary atresia or with Fallot's tetralogy with a shunt performed under the age of 3 years. In survivors, stenosis of the right pulmonary artery frequently occurred but was rarely severe. In view of these difficulties, early haemodynamic and angiocardiographic assessment is recommended in all patients with aorta to right pulmonary artery anastomosis, irrespective of the clinical result, in order to delineate the central pulmonary artery anatomy and assess perfusion of each lung; if kinking of the right pulmonary artery and inadequate perfusion of the central pulmonary arteries and left lung are demonstrated, early radical corrective surgery is recommended.