Ascaris suum hexokinase: purification and possible function in compartmentation of glucose 6-phosphate in muscle. Hexokinase (EC 2.7.1.1) is present in a soluble and a bound form in homogenates of Ascaris suum muscle. Cellulose acetate electrophoresis, isoelectric focusing, and ion exchange chromatography confirmed the presence of only one molecular form of hexokinase in this muscle. A procedure for purifying hexokinase from Ascaris muscle has been developed utilizing ion-exchange chromatography, ammonium sulfate fractionation and gel filtration. The enzyme is a monomer with a molecular weight of 100 000 as determined by sodium dodecyl sulfate gel filtration. The Stokes' radius, diffusion coefficient, and frictional ratio have been determined. The apparent Michaelis constants for glucose and ATP are 4.7-10(-3) M and 2.2-10(-4) M, respectively. Ascaris hexokinase also exhibits end-product inhibition by glucose 6-phosphate and ADP. It is postulated that the kinetic parameters of the enzyme are the results of its function, that of generating glucose 6-phosphate primarily for glycogen synthesis.


Selective inhibition of acyl-CoA dehydrogenases by a metabolite of hypoglycin. Extracts of liver mitochondria from donor rats given hypoglycin, the toxic amino acid from the ackee plant (Blighia sapida) showed drastically reduced levels of acyl-CoA dehydrogenase activity with butyryl-CoA as substrate. Activity with octanoyl- and palmitoyl-CoA was unaffected. Evidence that the active agent is methylenecyclopropylacetyl-CoA, a hypoglycin metabolite, was obtained by observing effects of the compound on a partially purified enzyme mixture prepared from rabbit liver. At 13 muM concentration, it strongly inhibited butyryl-CoA dehydrogenase (EC 1.3.99.2) with butyryl-CoA as substrate; it was far less effective with palmitoyl-CoA as substrate for the other similar enzymes present in the preparation. Unlike normal substrates of the acyl-CoA dehydrogenases, the compound itself, and not a reaction product, is inhibitory. The observed effect is consistent with quite general inhibition of fatty acid beta-oxidation by hypoglycin.


Purification, crystallization and properties of iron-containing superoxide dismutase from Pseudomonas ovalis. Three electrophoretically distinct superoxide dismutases (EC 1.15.1.1) were observed in the crude extracts from Pseudomonas ovalis. One of these was isolated as an iron-containing superoxide dismutase. It contained 1.4 gatoms of Fe per mol of enzyme, and had a specific activity of 3900 units per mg of protein. A crystallized enzyme contained 1.1 gatoms of Fe per mol of enzyme, and had a specific activity of 3100 units per mg of protein. The results of sedimentation equilibrium and gel filtration indicated a molecular weight of 40,000. S020,W was estimated as 3.18 by sedimentation velocity study. Sodium dodecyl sulfate gel electrophoresis indicated that the enzyme was composed of two subunits, and had a molecular weight of 19,500. Analysis for sulfhydryl groups showed that there were four such groups per mol of enzyme. The spectrum of visible and ultraviolet region, the amino acid composition, the CD spectrum of the enzyme, and the effect of certain compounds on the enzyme, were studied and compared with iron-containing superoxide dismutases isolated from other organisms.


Thymidylate synthetase of in vitro chemically and virally transformed rat cells. Thymidylate synthetase (EC 2.1.1) from in vitro 3-methylcholanthreneor Rauscher leukemia virus-transformed rat embryo cells was studied. The enzyme from control or transformed rat cells exhibited a Km for 2'-deoxyuridylic acid of 4.5 +/- 0.2 muM, but the transformants had a higher level of enzyme activity than did control cells. Titration of the enzyme with tritiated 5-fluoro2'-deoxyuridylic acid indicated that the increased enzyme activity in the transformants was due to a greater level of cellular enzyme. While the level of enzyme activity in control cells was dependent on both the availability of nutrients in the medium and cell density, the level of enzyme activity in the transformants appeared to depend only on the availability of nutrients.


A kinetic study of homocitrate synthetase activity in the yeast Saccharomycopsis lipolytica. 1. A rapid method for estimating the activity of the first enzyme of lysine biosynthesis in yeasts (acetyl-coenzyme A: 2-ketoglutarate C-acetyl transferase, EC 4.1.3.21) is described. 2. In the wild type strain, the fixation of one substrate, S-acetyl coenzyme A, shows sigmoidal saturation kinetics. The initial rate experiments indicate that the reaction obeys an ordered mechanism, 2-ketoglutaric acid binding before S-acetyl coenzyme A. 3. The activity is completely inhibited in vitro by lysine and by some lysine analogs, which all show cooperative binding and have an heterotropic effect on 2-ketoglutaric binding sites. A second class of affectors is found, including 2-aminoadipic acid, pipecolic acid and dipicolinic acid, which all affect the cooperativity of S-acetyl coenzyme A binding sites. 4. Two types of mutations which modify these inhibition patterns without affecting the catalytic activity are described. One results in a desensitization towards lysine and lysine analogs only. The other entirely abolishes the susceptibility towards the second type of inhibitors, without affecting the susceptibility to lysine. 5. No variations of the specific activity could be detected in the wild type strain at all; mutants showing an increased or a reduced activity were isolated. 6. Our results do not support the existence of isoenzymes at the level of homocitrate synthetase in this yeast.


Inhibition of photophosphorylation by ATP and the role of magnesium in photophosphorylation. ATP and pyrophosphate at high concentration (greater than 1 mM) inhibited photophosphorylation of isolated spinach chloroplasts in the normal salt medium and did not cause stimulation of electron transport. The inhibition of photophosphorylation by ATP or pyrophosphate was shown to be abolished by the addition of excess MgCl2, ADP and phosphate. It has been demonstrated that the rates of photophosphorylation in the absence and presence of ATP or pyrophosphate are determined similarly by the concentrations of magnesium-ADP (Mg - ADP-) and magnesiumphosphate (Mg - Pi) complexes. It is highly probable that Mg - ADP- and Mg - Pi, but not free ADP and free phosphate, are the active form of the substrates of photophosphorylation. This is in support of the view that ATP inhibits photophosphorylation by decreasing the concentration of Mg2+ which is available for the formation of the complex with ADP and phosphate.


The effects of oligomycin on energy metabolism and cation transport in slices of rat liver. Inhibition of oxidative phosphorylation as the primary action. 1. In slices of rat liver, oligomycin inhibited the net transport of Na+ and K+ by a maximum of 30% and endogenous respiration by 25%. These effects were not increased by a number of modifications in the incubation conditions. 2. Mitochondria isolated from the slices after incubation showed respiratory control ratios that were somewhat less than in mitochondria from fresh liver, but state 3 respiration retained normal sensitivity to oligomycin. 3. Low concentrations of oligomycin or cyanide reduced respiration and ATP levels of the slices but did not affect ion transport unless these levels fell below a definite critical value. In contrast, ouabain and atractyloside each caused substantial degrees of transport inhibition at ATP levels which were in excess of the critical value. 4. High concentrations of cyanide and oligomycin reduced ATP contents maximally by 90% and 65%, respectively. Studies of lactate production, and of the effects of arsenite on respiration and ATP levels, suggested that substrate-level phosphorylation in the citric-acid cycle was the major source of the oligomycinresistant ATP synthesis. 5. The results suggest that oligomycin acts in the liver slices primarily as an inhibitor of oxidative phosphorylation, and that this is the cause of the partial inhibition of ion transport. The oligomycin-resistant ion-transporting activity is consistent with the persisting level of ATP synthesis.


Mechanism of active shrinkage in mitochondria. I. Coupling between weak electrolyte fluxes. 1. A passive penetration of (NH4)2 HPO4 or of K2HPO4+nigericin occurs in respiratory-inhibited liver mitochondria. Addition of succinate at the end of the passive swelling initiates a shrinkage phase which leads to restoration of the initial mitochondrial volume. The rate and time of onset of the active shrinkage depend on the degree of stretching of the mitochondrial membrane. The rate of active shrinkage increases proportionally to the concentration of nigericin while it is strongly inhibited by valinomycin. 2. A number of SH inhibitors such as N-ethylmaleimide, p-chloromercuribenzoate, p-chloromercuriphenylsulphonate, dithiobisnitrobenzoate, exert a marked enhancing effect on the rate of shrinkage. The enhancing effect parallels titration of the phosphate carrier and inhibition of the passive phosphate efflux. In contrast, mersalyl is a powerful inhibitor of the rate of active shrinkage. The inhibition parallels that on phosphate passive efflux and requires higher mersalyl concentrations in respect to inhibition of phosphate influx. 3. The active shrinkage is discussed in terms of (a) a mechanoenzyme, (b) an electrogenic proton pump and (c) a proton-driven Pi pump.


In vitro preparation and characterization of a 700 nm absorbing chlorophyll-water adduct according to the proposed primary molecular unit in photosynthesis. 1. This study characterized chlorophyll a-H2O adducts in vitro in order to establish their generic relationship to the recently proposed [15, 18-20, 31] primary molecular adduct in photosynthesis. The effects of water titration and temperature on the absorption, fluorescence, excitation, and redox properties of the various in vitro chlorophyll a aggregate species are investigated. 2. From fluorescence measurements, we conclude that the driest chlorophyll a sample contains an equimolar amount of water. This conclusion is consistent with earlier experimental work [2, 3, 14, 17, 31], and clarifies the origin of the controversial [15] Katz model [14] of chlorophyll a-H2O interactions. 3. With increasing water concentration or as the temperature is lowered below room temperature, the A-663 monohydrate chlorophyll a-H2O (species absorbing at 663 nm) is favored at the expense of the A-678 anhydrous aggregate according to the equilibrium 2H2O+chlorophyll a2in equilibrium2 chlorophyll a-H2O. Under excess water conditions, A-663 is converted to A-743 (chlorophyll a-2H2O)n. 4. On slow sample cooling to T less than or approximately 200 degrees K, we observe the growth of A-700 at the expense of A-663. There is a direct correspondence between the increasing (decreasing) absorption by A-700 (A-633) and increasing (decreasing) fluorescence at 720 nm (664 nm). 5. It is concluded that A-700 is most probably the dimer participating in the equilibrium 2 chlorophyll a-H2O in equilibrium (chlorophyll a-H2O)2. The A-700 band consists of two exciton components (separated by approximately 280 cm1) that are interpretable in terms of the dimeric origin of A-700. 6. The deconvoluted A-700 absorption spectrum and the excitation spectrum of the 720 nm fluorescence are compared with the light-minus-dark spectra of P-700. 7. It is found that A-700 is reversibly bleached by I2 (E0 equals 0.54 V). The significance of this observation is discussed in terms of the redox properties of monomeric chlorophyll a and P-700.


A mutant strain of Scenedesmus obliquus deficient in ribulose diphosphate carboxylase, cytochrome f and photosystem II activity. The partial reactions of photosynthesis shown by strain F208, a non-photosynthetic mutant strain of Scenedesmus obliquus, have been compared with those performed by other mutant strains which lacked; Photosystem II activity (strains 11 and F131), cytochrome f (strain 50), P-700 and cytochrome f (strain F 119), and P-700 (strains F139 and 199). In this respect the properties of strain F208 were those that would be expected if Photosystem II activity and cytochrome f were not present in this strain. Examination of the composition of strain F208 has shown the absence of cytochrome f in both the soluble and the membrane-bound form. The considerably lower level of plastoquinone compared to that found in the wild type is characteristic of the strains which lack Photosystem II activities. Fraction 1 protein could not be detected in extracts of strain F208 by sedimentation velocity experiments in the ultracentrifuge, and only 7% of the wild type ribulose diphosphate carboxylase activity was found after chromatography of these extracts on DEAE-cellulose. The properties of strain F208 are compared with those of the ac-20 and cr-1 strains of Chlamydomanas rheinhardi, both of which have a deficiency of ribulose diphosphate carboxylase which is considered to result from a deficiency of chloroplast ribosomes. Strain F208 resembles these strains in its abnormal chloroplast ultrastructure and its decreased levels of the RNA forms derived from the chloroplast ribosomes when compared with the wild type. Chloroplast fragments isolated from strains of S. obliquus which lacked cytochrome f (strains 50 and F208) were able to use diaminodurene and ascorbate as an electron donor to Photosynstem I. Since this reaction was inhibited by mercuric salts it would appear that plastocyanin, but not cytochrome f, was involved in this electron transfer.


Rates and properties of endogenous cyclic photophosphorylation of isolated intact chloroplasts measured by CO2 fixation in the presence of dihydroxyacetone phosphate. 1. Dihydroxyacetone phosphate in concentrations greater than or equal to 2.5 mM completely inhibits CO2-dependent O2 evolution in isolated intact spinach chloroplasts. This inhibition is reversed by the addition of equimolar concentrations of Pi, but not by addition of 3-phosphoglycerate. In the absence of Pi, 3-phosphoglycerate and dihydroxyacetone phosphate, only about 20% of the 14C-labelled intermediates are found in the supernatant, whereas in the presence of each of these substances the percentage of labelled intermediates in the supernatant is increased up to 70-95%. Based on these results the mechanism of the inhibition of O2 evolution by dihydroxyacetone phosphate is discussed with respect to the function of the known phosphate translocator in the envelope of intact chloroplasts. 2. Although O2 evolution is completely suppressed by dihydroxyacetone phosphate, CO2 fixation takes place in air with rates of up to 65 mu mol-mg1 chlorophyll-h1. As non-cyclic electron transport apparently does not occur under these conditions, these rates must be due to endogenous pseudocyclic and/or cyclic photophosphorylation. 3. Under anaerobic conditions, the rates of CO2 fixation in presence of dihydroxyacetone phosphate are low (2.5-7 mumol-mg1 chlorophyll-h1), but they are strongly stimulated by addition of dichlorophenyl-dimethylurea (e.g. 2-10(-7) M) reaching values of up to 60 mumol-mg1 chlorophyll-h1. As under these conditions the ATP necessary for CO2 fixation can be formed by an endogenous cyclic photophosphorylation, the capacity of this process seems to be relatively high, so it might contribute significantly to the energy supply of the chloroplast. As dichlorophenyl-dimethylurea stimulates CO2 fixation in presence of dihydroxyacetone phosphate  under anaerobic but not under aerobic conditions, it is concluded t-at only under anaerobic conditions an "overreduction" of the cyclic electron transport system takes place, which is removed by dichlorophenyl-dimethylurea in suitable concentrations. At concentrations above 5-10(-7) M dichlorophenyl-dimethylurea inhibits dihydroxyacetone phosphate-dependent CO2 fixation under anaerobic as well as under aerobic conditions in a similar way as normal CO2 fixation. Therefore, we assume that a properly poised redox state of the electron transport chain is necessary for an optimal occurrence of endogenous cyclic photophosphorylation. 4. The inhibition of dichlorophenyl-dimethylurea-stimulated CO2 fixation in presence of dihydroxyacetone phoshate by dibromothymoquinone under anaerobic conditions indicated that plastoquinone is an indispensible component of the endogenous cyclic electron pathway.


Further studies on the effect of phosphoenolpyruvate on respiration-dependent calcium transport by rat heart mitochondria. Phosphoenolpyruvate was found to depress extra oxygen consumption associated with Ca2+ -induced respiratory jump by rat heart mitochondria. Addition of phosphoenolpyruvate to mitochondria which have accumulated Ca2+ in the presence of glutamate and inorganic phosphate causes the release of Ca2+ from mitochondria. The phosphoenolpyruvate-stimulated Ca2+ efflux can be observed with mitochondria loaded with low initial Ca2+ concentration (0.12 mM) in the incubation medium. Measurements of mitochondrial H+ translocation produced by addition of Ca2+ to respiring mitochondria show that phosphoenolpyruvate depresses H+ ejection and enhances H+ uptake by mitochondria. The Ca2+ -releasing effect of phosphoenolpyruvate was found to be significantly stronger than that produced by rotenone when added to mitochondria loaded with Ca2+ in the presence of glutamate and inorganic phosphate. Dithiothreitol cannot overcome the effect of phosphoenolpyruvate on mitochondrial Ca2+ transport.


Chlorophyll and peptide compositions in the two photosystems of marine green algae. The molar ratios of chlorophyll a to b in the thalli of marine green algae were between 1.5 and 2.2, being appreciably lower than the ratio between 2.8 and 3.4 found for the leaves of higher plants and the cells of fresh-water green algae. The ratio of chlorophylls to P-700 in these marine algae was also lower than that in higher plants. The a/b ratios in the pigment proteins of Photosystems 1 and 2 separated by polyacrylamide-gel electrophoresis from sodium dodecyl sulfate-solubilized chloroplasts of four species of marine green algae, Bryopsis maxima, Cheatomorpha spiralis, Enteromorpha compressa and Ulva conglobata, were approximately 5 and 1, which are considerably smaller than the ratios, 7 and 2, respectively, found for the pigment proteins of the two photosystems of higher plants separated by the same technique. The chloroplasts of Bryopsis maxima and Cheatomorpha spiralis lacked two of the peptides associated with Photosystem II, which are present in the chloroplasts of Spinacia oleracea and Taraxacum officinale.


Kinetic studies of phototransients in bacteriorhodopsin. Aqueous suspensions of bacteriorhodopsin in purple membrane fragments from Halobacterium halobium have bben subjected to microsecond flash photometry utilizing both unpolarized and polarized light. Depletion of the ground state chromophore centered at 570 nm is accompanied by the formation of transients absorbing maximally at 410 nm and 660 nm with rise times of about 0.4 and 6 ms, respectively. Decay of both transients and reformation of the ground state chromophore occurs with identical first-order kinetics with a half life of about 6 ms. All three chromophores are polarized with dichroic ratios which remain constant throughout the transient lifetimes, indicating that Brownian rotation of the chromophore within the membrane is considerably restricted. Whereas agents which induce permeability of membranes to protons (2,4-dinitrophenol, carbonylcyanide-m-chlorophenylhydrazone) and non-specific univalent cations (gramicidin) or inhibit ATPase (ouabain) had no influence, the K+-specific ionophore valinomycin in the presence of K+ inhibited and quenched the formation of the 660 nm transient with concomitant increase in lifetime of the 410 nm transient and delay in recovery of the 570 nm chromophore. High concentrations of Na+ produced an effect similar to that of valinomycin. The relationship of these data to the mechanism of the proton pump in the intact bacterium is discussed, with the conclusion that the 410 nm transient performs a key role.


Analysis of temperature-jump chlorophyll fluorescence induction in plants. A newly observed general chlorophyll fluorescence induction effect in plants is described. Fluorescence yield can rise through as many as four different phases (alpha, beta, gamma, ) in the dark, when intact cells or leaves are rapidly heated (within approx. 2.5 s) from 20 to 40-50 degrees C. An analysis of this temperature-jump fluorescence induction in Scenedesmus obliquus leads to the following: 1. Phase alpha is due to removal of S-quenching and appears to be related to heat deactivation of the water-splitting enzyme system. With prolonged heating, irreversibility of alpha upon recooling reflects irreversible damage to the water-splitting enzyme system. 2. beta is independent of the S-states and of the redox state of primary System II acceptor Q. It is suggested that beta parallels functional separation of Q from the System II trapping centre. This effect is highly reversible. 3. gamma and beta reflect reduction of primary System II acceptor Q by a heat-induced endogenous reductant, which is probably identical to hydrogenase. Critical temperatures for pronounced alpha and beta phases differ markedly in different plants. Possible correlations between temperature-jump fluorescence inductio, thylakoid membrane lipid composition, lipid phase transition and lipid-protein interactions are discussed.


Studies on the slow fluorescence decline in isolated chloroplasts. Data presented here indicate that the slow fluorescence decline in osmotically disrupted chloroplasts is not associated with the well known divalent cation effect on fluorescence yield. Thus the two phenomena have markedly different magnesium concentration requirements, magnesium addition after the fluorescence decline did not stimulate the dark reversal, and the characteristics of the fluorescence induction kinetics of the two processes are not similar. At pH 7.6 the slow fluorescence decline was stimulated by several uncouplers demonstrated to greatly reduce proton pumping, and at pH 9.2 it was stimulated by all uncouplers tested. Acid-base transition was strongly inhibitory, and this inhibition was relieved by coupling factor is suggested by experiments in which phosphorylation substrates were inhibitory, and this inhibition was prevented by uncoupler. These data are explained in terms of coupling factor structural changes which in an unknown manner influence Photosystem II fluorescence emission. Fluorescence induction curves indicate that the slow quenching decreased only the variable fluorescence. The half rise time was decreased along with the sigmoidicity of the rise curve. These data can be accomodated in terms of a model recently proposed by Butler and Kitajima (Biochim. Biophys Acta (1975) 376, 116-125), involving the transfer of energy from the excited, but closed, reaction centres II to the light harvesting chlorophyll system. The slow fluorescence decline is suggested to represent a decrease of this process.


Cytochrome b-563 redox changes in intact CO-fixing spinach chloroplasts and in developing pea chloroplasts. Intact spinach chloroplasts, capable of high rates of photochemical oxygen evolution with CO2 as electron acceptor (120-350 mumol O2 mg chlorophyll-1 h-1) were examined for cytochrome redox changes. The response of the cytochromes in intact chloroplasts to oxidants and reductants appears to be governed by the permeability of the chloroplast envelope. The low potential cytochromes (b-559LP and b-563) were more slowly reduced at 25 degrees C by dithionite than is the case with broken chloroplasts. At 0 degrees C, the reduction of the low potential cytochromes in intactchloroplasts was extremely slow. The chloroplast envelope is impermeable to ferricyanide, slowly permeable to ascorbate and rapidly permeable to reduced dichlorophenolindophenol. Light-induced redox changes of cytochrome b-563 in intact chloroplasts were examined both at 0 degrees and 25 degrees C. A red/far-red antagonism on the redox changes of cytochrome b-563 was observed at 0 degrees C under anaerobic conditions. 3-(3,4-dichlorophenyl)-1, 1-dimethlyurea (DCMU) inhibited the photoreduction of cytochrome b-563 in red light following far-red illumination. The photooxidation of cytochrome b-563 under anaerobic conditions was not influenced by  DCMU or 2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone (DBMIB). The photoreduction of cytochrome b-563 under aerobic conditions was much less efficient than its photooxidation under anaerobic conditions. Developing pea chloroplasts showed much greater light-induced redox changes of cytochrome b-563 than did intact spinach chloroplasts. Our data are consistent with the view that cytochrome b-563 functions on a cyclic pathway around Photosystem I, but it appears that cyclic flow is sensitive to the relative poising of the redox levels of cytochrome b-563 and the components of the non-cylic pathway.


DNA synthesis in permeabilized mouse L cells. Mouse L cells are rendered permeable to nucleoside triphosphates by a cold shock with a near isotonic buffer. These cells retain their morphologic integrity and use exogenously supplied nucleotides and deoxynucleotides to synthesize RNA and DNA. The newly synthesized DNA is nuclear and is the product of semiconservative replication. Incorporation of deoxynucleotides into DNA by thymidine kinase-deficient cells were used to conform rigorously that the exogenously supplied deoxynucleotides were incorporated into DNA without intermediate processing through nucleosides. DNA synthesis requires the presence of Na+, ATP, all 4 deoxynucleotides, and Mg2+. The reaction is inhibited by N-ethylmaleimide, p-hydroxymercuribenzoate and actinomycin D. Hydroxy-urea and arabinosylcytosine do not inhibit the reaction whereas cytosine arabinoside triphosphate shows competitive inhibition with the deoxynucleotides. These findings indicate that the permeable cell system can be used for in situ evaluations of the replicative DNA polymerase using the endogenous DNA template.


Stimulation of RNA polymerases I, II and III from rat liver by spermine, and specific inhibition of RNA polymerase I by higher spermine concentrations. Spermine stimulates activities of higherly purified rat liver nuclear RNA olymerases I, II and III 3 to 4 fold. Inclusion of (NH4)2SO4 at concentrations required for maximal enzyme activities does not significantly enhance the degree of stimulation of polymerase activities by spermine, but maintains the stimulatory levels of enzymes over a broader range of spermine concentrations. The stimulatory effect of spermine at a concentration of 1 mM is a useful method for the elevation of activities of all RNA polymerases and thus provides a means to measure these enzymes when extracted from small quantities of tissues or cells. Based on the differential stimulation of the polymerases by spermine, a higher concentration of spermine (5 mM) can be selected to inhibit RNA polymerase I specifically.


Mode of extension of the daughter strands in the replication of closed circular mitochondrial DNA in vitro. 1. The properties of nascent DNA in the replicative closed circular mitochondrial DNA were examined in the in vitro system of discontinuous replication, using newborn rat liver mitochondria containing endogeneous DNA templates and enzymes. 2. The nascent DNA associated with the closed circular DNA fraction was found to be of two types; one class consisted of the fragments, and the other of the higher molecular-weight DNAs. Data from pulse and chase experiments indicate that the fragments were initially synthesized and subsequently converted into both heavy and light strands of the higher molecular-weight DNAs in an asymmetrical mode. 3. DNA - DNA hybridization experiments revealed that half of the fragments at least were copies of complementary parts of the parental DNA. 4. Based on the present in vitro data, a tentative structure of the replicating region and its expansion are discussed.


Analysis of the genome of plants. II. Characterization of repetitive DNA in barley (Hordeum vulgare) and wheat (Triticum aestivum). Barley and wheat DNAs have been characterized by studying their kinetics of reassociation, melting properties and sedimentation behaviour in neutral CsCl gradients as well as in Cs2SO4 gradients containing Ag+ or Hg2+. In both species, reassociation kinetics have revealed the presence of approx. 76% redundant nucleotide sequences which have been grouped into very rapidly reassociating (Cot 0-0.01), rapidly reassociating (Cot 0.01-1.0) and slowly reassociating (Cot 1-100) fractions. The barley Cot 0-0.01 and Cot 0.01-1.0 fractions as well as the wheat Cot 0.01-1.0 fraction form narrow bands upon centrifugation in CsCl gradients. Under similar experimental conditions both Cot 0.01 and Cot 1.0-100 wheat fractions and the barley Cot 1.0-100 fraction form broad bands each having several shoulders. Thermal denaturation studies of most of the above reassociated fractions have shown a considerable degree of order in their duplexes with an average hyperchromicity of 21.5%. When native, high molecular weight barley DNA is centrifuged in Ag+/CS2SO4 density gradients (RF = 0.2), two satellites appear on the heavier side of the main band, as against one in the case of wheat. The two minor peaks, designated as satellites I and II, have buoyant densities of 1.702 and 1.698 g/cm3, respectively, in neutral CsCl gradients and together represent about 8-9% of total barley DNA. Upon centrifugation in Hg2+/CS2SO4 density gradients, one satellite is observed in both barley and wheat and it accounts for 1-2% of their genomes.


In vitro DNA and RNA synthesis by human platelets. In vitro incorporation of [Me-3H] thymidine and [5-3H] uridine into human platelets was demonstrated. Thymidine incorporation was inhibited by three specific inhibitors of DNA synthesis: hydroxyurea, cytosine arabinoside and daunomycin. The effect was dose-dependent. Uridine uptake by platelets was found to be inhibited by specific inhibitors of RNA synthesis such as actinomycin D, rifampicin and vincristine, the effect of actinomycin D being dose dependent. The drug also led to a time-dependent inhibition of protein synthesis when preincubated with platelets. The platelet RNA profile on polyacrylamide gel was demonstrated to be similar to that of embryonic mouse erythroblast RNA. Synthesis of all three fractions, 28 S, 18 S and 4 S, was inhibited by actinomycin D. These findings show that human platelets are capable  of DNA and RNA synthesis, and that these activities play a role in controlling protein synthesis in these cells. Detectable amounts of DNA have been found in whole human platelets, and in isolated mitochondria derived from these cells. Isolated platelet mitochondria incorporated [3H] thymidine and [3H] uridine into their macromolecules. These activities were inhibited by daunomycin and by both rifampicin and actinomycin D, respectively. These results support the assumption that DNA and RNA synthesis found in intact cell preparations takes place most probably in platelet mitochondria.


Embryonic stage-related properties of sea urchin embryo chromatin. Two chromatin components, obtained by buoyant density centrifugation of the unsheared blastula and gastrula chromatin of a sucrose/glucose gradient, have been comparatively characterized. When compared to the heavy fraction the light fraction (i) represents a far smaller part of chromatin, (ii) contains a higher RNA/DNA mass ratio and a higher proportion of newly synthesized nonhistone proteins and (iii) possesses greater template activity for RNA synthesis. Gastrulation of the embryos was found to render the dense chromatin fraction less compact and both chromatin subpopulations more transcriptable and enriched with newly synthesized non-histone proteins.


Structure of eukaryotic chromatin. Evaluation of periodicity using endogenous and exogenous nucleases. DNA isolated from (a) liver chromatin digested in situ with endogenous Ca2+, Mg2+-dependent endonuclease, (b) prostate chromatin digested in situ with micrococcal nuclease or pancreatic DNAase I, and (c) isolated liver chromatin digested with micrococcal nuclease or pancreatic DNAase I has been analyzed electrophoretically on polyacrylamide gels. The electrophoretic patterns of DNA prepared from chromatin digested in situ with either endogenous endonuclease (liver nuclei) or micrococcal nuclease (prostate nuclei) are virtually identical. Each pattern consists of a series of discrete bands representing multiples of the smallest fragment of DNA 200 +/- 20 base pairs in length. The smallest DNA fragment (monomer) accumulates during prolonged digestion of chromatin in situ until it accounts for nearly all of the DNA on the gel; approx. 20% of the DNA of chromatin is rendered acid soluble during this period. Digestion of liver chromatin in situ in the presence of micrococcal nuclease results initially in the reduction of the size of the monomer from 200 to 170 base pairs of DNA and subsequently results in its conversion to as many as eight smaller fragments. The electrophoretic pattern obtained with DNA prepared from micrococcal nuclease digests of isolated liver chromatin is similar, but not identical, to that obtained with liver chromatin in situ. These preparations are more heterogeneous and contain DNA fragments smaller than 200 base pairs in length. These results suggest that not all of the chromatin isolated from liver nuclei retains its native structure. In contrast to endogenous endonuclease and micrococcal nuclease digests of chromatin, pancreatic DNAase I digests of isolated chromatin and of chromatin in situ consist of an extremely heterogeneous population of DNA fragments which migrates as a continuum on gels. A similar electrophoretic pattern is obtained with purified DNA digested by micrococcal nuclease. The presence of spermine (0.15 mM) and spermidine (0.5 mM) in preparative and incubation buffers decreases the rate of digestion of chromatin by endogenous endonuclease in situ approx. 10-fold, without affecting the size of the resulting DNA fragments. The rates of production of the smallest DNA fragments, monomer, dimer, and trimer, are nearly identical when high molecular weight DNA is present in excess, indicating that all of the chromatin multimers are equally susceptible to endogenous endonuclease. These observations points out the effects of various experimental conditions on the digestion of chromatin by nucleases.


Polyadenylate polymerase from cytoplasm and nuclei of N.I.H.-Swiss mouse embryos. Poly (A) polymerase activity from cytoplasm and nuclei of 12-16-day-old mouse embryos has been partially purified by (NH4)2SO4 fractionation, DEAE-cellulose, phosphocellulose and tRNA-Sepharose affinity chromatography, and their properties have been compared. The nuclear and cytoplasmic enzymes exhibit similar chromatographic elution profiles, and similar biochemical and physical properties. Poly(A) polymerase has an absolute requirement for a divalent cation, ATP and an oligo- or polyribonucleotide primer. With tRNA, the divalent salt  concentrations for optimum enzyme activity are 1 mM MnCl2 or 10 mM MgCl2. The enzyme activity with MnCl2 is 10-15-fold higher than that with MgCl2. The molecular weight of the native enzyme is about 65 000 and its sedimentation coefficient is around 4.5 S. The average chain length synthesized by the enzyme is between 10 and 13 nucleotides. The inhibitors of RNA polymerase do not affect poly (A) polymerase activity; however, some synthetic rifamycin SV derivatives are potent inhibitors of this enzyme.


Effect of metabolic state on agglutination of human erythrocytes by concanavalin A. Intact freshly drawn or stored human erythrocytes, which show little agglutination by concanavalin A, become agglutinable by this lectin in the presence of adenosine. alpha-Methylglucose (10 mM) completely inhibits this agglutination. The concanavalin A agglutination shows no sensitivity to vinblastine or cytochalasin B. Resealed membranes preparaed with ATP in lysing and resealing medium give modest agglutinability, while the presence of adenosine in both the lysing and the resealing medium results in a substantial agglutinability of the resealed membranes. Mild trypsin treatment of the erythrocytes causes an enhanced sensitivity to adenosine activation of the concanavalin A agglutination, while extensive trypsin treatment produced highly agglutinable erythrocytes that shown no response to the presence of adenosine in the lectin solution. The extensively treated erythrocytes also show concanavalin A agglutination at temperatures below 37 degrees C, under conditions in which intact or moderately treated erythrocytes do not agglutinate, with or without adenosine present. Results suggest that the adenosine activation of concanavalin A agglutination of intact human erythrocytes is mediated through a metabolic conversion of adenosine to a rapidly turned over metabolite which participates directly in the activation of agglutination. The agglutinability does not appear to depend on whole cell ATP levels, but may involve a particular pool of ATP. The effect of variation of cellular metabolic state and the response of particular systems involved in lectin-mediated agglutinability to cellular metabolism seem to be worth consideration in explaining the frequently large differences in agglutinability of und in cells in different biological states, such as those encountered in normal and transformed cells.


Protease digestion of membranes. Ultrastructural and biochemical effects. (1) Nagarse, a bacterial protease, was permitted to react with sarcoplasmic reticulum, submitochondrial and plasma membranes. Gel electrophoresis indicated that all polypeptides were labile to the enzyme, and therefore must be at least partially exposed at membrane surfaces. However, hydrolysis did not proceed to completion, and in each membrane 30-50% of the original protein mass remained after extensive digestion. Gel patterns showed that remaining polypeptide fragments were in the range of 10000 molecular weight. (2) Amino acid analysis of the original protein and membrane-bound digestion product was performed. Only minor changes were observed following digestion, suggesting that the peptide fragments remaining with the membrane did not have specialized amino acid compositions. (3) freeze-fracture analysis of Nagarse-treated sarcoplasmic and plasma membranes showed that particulate structures were present, although particle density and asymmetry of fistribution between fracture faces were decreased. In submitochondrial membranes, digested membranes were indistinguishable from the original membranes in particle density and distribution. We conclude that high molecular weight polypeptides are not required for the production particulate structures in freeze-fracture images of membranes.


Interaction of the polyene antibiotics with lipid bilayer vesicles containing cholesterol. The interaction of the polyene antibiotics, amphotericin B, nystatin and filipin with cholesterol-containing single bilayer lipid vesicles has been characterized using gel permeation chromatography and proton magnetic resonance. All three antibiotics bind to vesicles at low concentrations without causing a large amount of vesicle destruction. The strength of binding as determined by gel permeation studies is greater for filipin and amphotericin than for nystatin. Nystatin and amphotericin B at these low concentrations induce a rapid loss of internal vesicle contents consistents consistent with pore formation. Filipin induces no leakage beyond that expected from partial vesicle destruction or general detergent action. At antibiotic levels above 1:1 antibiotic: cholesterol ratios the NMR results show all three antibiotics to cause extensive vesicle destruction. The onset of this behavior, which appears to be independent of the total antibiotic concentraion, indicates a well defined antibiotic : cholesterol interaction stoichiometry. Despite the fact that cholesterol is required for antibiotic activity, the NMR spectra prior to vesicle destruction show no changes indicative of an antibiotic-induced reversal of cholesterol restriction of phosphatidylcholine mobility. The contrast with polyene antibiotic behavior in more extended bilayers is discussed.


Alkyl glucosides as effective solubilizing agents for bovine rhodopsin. A comparison with several commonly used detergents. The suitability of octyl and decyl-beta-D-glucoside as solubilizing agents for the bovine retinal rod outer segment disc membrane was investigated and compared to that of hexadecyltrimethylammonium bromide, N,N-dimethyldodecylamine oxide, Emulphogene BC-720 and digitonin. The properties measured included the thermal stability of rhodopsin, regenerability of bleached rhodopsin by addition of 11-cis-retinal, and the rate of denaturation of bleached rhodopsin as measured by changes in the ultraviolet CD spectrum. Denaturing tendencies of the detergents were also evaluated by observing their effects on the absorption and CD spectra of sperm whale metmyoglobin. Our results demonstrate that octyl glucoside is superior to the other detergents, with the possible exception of digitonin, by the above criteria. Unlike digitonin, however, octyl glucoside affords rapid solubilization of the disc membrane and is itself highly soluble. Decyl glucoside has properties equivalent or superior to octyl glucoside, but salts and buffers interfere with its ability to solubilize the disc membrane. The well defined chemical composition, ease of removal by dialysis, and non-denaturing properties of the alkyl glucosides make them attractive detergents for membrane research.


Effect of temperature on growth of newborn rabbits. The effect of cold exposure upon rabbits was investigated in order to study the interrelationships of food intake, growth and metabolic rate. Newborn rabbits were raised in 2 groups at environmental temperatures that produced a 50-100% difference in metabolic rate. No difference in growth rate or milk intake was apparent. Nucleic acid and protein content of several organs were measured and were similar. The paradox of a similarity in weight gain between the groups in the face of a similar intake of milk but different oxygen consumptions is discussed.


Fibrinolysis, fibrinogen and trhombin time in newborns. Comparative experiments were made on blood samples collected with and without addition of a potent fribinolysis-blocking agent in newborn infants aged up to 12 h. Prevention of the in vitro fibrinolysis resulted in a diminished frequency of an abnormal euglobulin clot lysis time, but there was no significant difference in fibrinogen levels and in the frequency and degree of a prolonged thrombin time. These results indicate that the prolongation of thrombin time in newborn infants cannot be prevented by blocking the in vitro fibrinolysis. The significance of these findings is discussed with regard to the possible existence of an abnormal 'fetal fibrinogen'.


Histological structure of the thyroid gland in the newborn. With special reference to hypotrophy, hydrops fetalis and Cesarean section delivery. Histological features of the thyroid gland in the newborns have been described under several circumstances; gestational age, length of survival, and under particular clinical status such as hypotrophy (intrauterine growth retardation), Cesarean section delivery and hydrops fetalis. Gestational age does not modify significantly the histological aspect of the thyroid, while birth process and adjustment to extrauterine life induce dramatic changes such as severe depletion of colloid for about 24 h, followed by a massive repletion after the first day of life. A few exceptions to this phenomenon are described. Thyroid glands of hypotrophic infants and of infants delivered by cesarean section exhibit colloid-filled vesicles already within the first day. Thyroid glands of hydrops fetalis have a reverse tendency. This phenomenon might be secondary to multiple exchange transfusions.


Metabolism of natural and synthetic corticosteroids in relation to their effects on mouse fetuses. 14C-glucose uptake by mouse fetuses was reduced by doses of dexamethasone, 200 mug or more, which over 2 days caused fetal death. Uptake by strain C57B1/6J greater than A/J greater than SWV. Corticosterone or cortisol, 4 mg, caused neither reduced uptake nor fetal death. These differences occurred despite similar maternal hyperglycemia in all cases. Recovery of 3H-steroid after 15 min, total and unchanged steroid per gram fetal tissue was: corticosterone 1.7 and 0.3%; dexamethasone 0.12 and 0.06% of the dose. Rapid metabolism of corticosterone apparently prevents accumulation in fetal tissue sufficient to evoke a response under these conditions.


Transfer RNA and aminoacyl transfer RNA in developing rats. The total transfer RNA (tRNA) level in the liver, kidney, skeletal muscle and heart muscle of developing rats was determined by purification using (3H)tRNA as an internal standard. Liver and kidney contained almost twice as much tRNA per gram tissue as heart and skeletal muscle. There were no apparent differences between the sexes. The aminoacylation capacities of six tRNA species (alanyl, aspartyl, leucyl, methionyl, phenylalanyl, and tryptophanyl) from rat liver were not different during 3 developmental stages (suckling, weaning and young adult), and there were also no differences noted between males females. The in vivo percent aminoacylation of 4 tRNAs (aspartyl, leucyl, methionyl, and phenylalanyl) was lower during the newborn and suckling periods than in weaning and young adult rat livers. The tRNA of young adults was almost completely aminoacylated in vivo with the exception of alanyl-tRNA.


Acetylcholinesterase activity in the erythrocytes of newborn infants with hyperbilirubinemia and asphyxia. The authors measured erythrocyte acetylcholinesterase (ACHE) activity in  51 physiologic newborn infants, 35 pregnant women and 101 infants with hyperbilirubinemia caused by hemolytic diseases in the ABO and Rh systems, or of other origin (6 children). In total, 374 examinations of erythrocyte ACHE were performed. The normal values of physiologic infants during the first hours of life were 0.162 +/- 0.03, at the age of 3 days 0.104 +/- 0.04. The values in pregnant women were 0.206 +/- 0.07. The ACHE activity was considerably decreased in newborn infants affected by erythroblastosis-ABO, and its mean value, in the case of exsanguinotransfusion indicated by the Polácek scheme, amounted to 0.060 +/- 0.051. It raised after exsanguinotransfusion and was equal to the value of red cells transfused. In newborn infants affected by erythroblastosis-Rh, the value decreased in the cases complicated with asphyxia. Low values of ACHE are sometimes found in certain cases of IRDS or of septicemia. The determination of erythrocyte ACHE activity enables assessing the state of red blood cells.


Relationship between body size, thermal balance and thermal insulation of term infants under various ambient conditions. A gradient layer direct calorimetric study was made on the thermal balance of small-for-date, appropriate-for-date and large-for-date term newborn infants during the first 2 days of life. At ambient temperatures of 28 and 32 degrees C, the dry and total heat losses per kilogramme body weight were inversely related to body weight. There was a negative correlation between metabolic rate per kilogramme and body weight, whereas in terms of surface area the correlation became positive. A similar tendency without statistical significance was observed at an ambient temperature of 37 degrees C. In a cool environment (28 degrees C), a significant positive correlation was found between body weight and ambient or total thermal insulations. Tissue and total insulations were inversly related to the metabolic rate. It was concluded that small-for-date newborn infants are handicapped not only by the unfavourable surface-to-mass ratio but also by the limited specific body thermal insulation.


Tissue glycogen and blood glucose and fructose levels in the pig fetus during the second half of gestation. Tissue glycogen levels in the liver, cardiac ventricle, lung, thigh muscle, kidney and placenta were determined in pig fetuses of 60-112 days gestational age. Liver glycogen levels increased earlier in gestation than suggested by previous reports although the maximum  rate of deposition occurred between 100 and 107 days. The time of deposition of muscle glycogen was similar to that of the liver. Lung glycogen levels peaked between 70 and 90 days but then fell rapidly in late gestation. Cardiac levels were similar at all ages studied. Blood fructose levels were high in younger fetuses but levels were lower in older fetuses and were falling rapidly between 107 and 112 days. Maternal blood contained only traces of fructose. Fetal blood glucose levels were lower than maternal levels and appeared to be more closely related to maternal levels than to the gestational age of the fetuses.


Isoelectric focusing of non-specific esterases of developing human brain in thin-layer polyacrylamide gels. Isoelectric focusing in thin-layer polyacrylamide gels shows differences between the non-specific esterase patterns of human fetal and adult brains. This heterogeneity is as expected from starch gel electrophoresis. The discrepancy with the only previous report on this subject is discussed, and is attributed to differences in the experimental conditions employed.


New ultrasonic device for monitoring foetal breathing movements. Ultrasonography is the accepted method of choice for registering foetal breathing movements in man. The conventional apparatus hitherto used for this purpose is disadvantageous and could yield misleading artefacts. A new differential echoscope has been designed and developed especially for recording intrauterine foetal movements. It allows a simultaneous registration of movements of two foetal structures: the proximal and distal thoracic wall, or the foetal heart and the thoracic wall. It is equipped with two alternately emitting transducers, each with a repetition frequency of 150 HZ, and an intensity-modulated display of the triggering echoes within the gates. Time-to-volgate converters transform the movements of two gated echoes into electrical signals. An internal differential circuit produces on-line recordings of the true difference between movements of the two selected echoes. This device will appreciably facilitate the selection of proper echoes and reduce signal artefacts during foetal monitoring. Various errors and pitfalls in measuring foetal breathing movements are discussed.


Hypothenar muscle action potential recorder. Drugs which block the transmission of excitation from motor nerve to voluntary muscle fibre are used routinely in anaesthesia. The action of this group of drugs may be studied by stimulating a motor nerve and observing the evoked muscle response. Simple nerve stimulators are widely available and are designed to achieve supramaximal stimulation of a convenient peripheral motor nerve. Quantitative observation of the evoked muscle response is achieved by measuring either the action potential or the tension developed by the contracting muscle. While such techniques are commonly used for research and teaching purposes, they are not widely available to the practising anaesthetist. Electrocardiography, on the other hand, id frequently used in operating theatres and recovery rooms, so that medical personnel are accustomed to using ECG recorders and are trained to interpret the displayed information. We have developed an EMG pre-amplifier and signal processor to produce a signal which can be displayed by ECG equipment.


Chequerboard pattern reversal using a modified television display to measure visual evoked responses. The clinical value of visual evoked response measurement is noted with particular reference to the stimulus source used. The complexities of response to brief flashes of light has led to the increased use of chequerboard reversal as a stimulus source. Thus far, the chequerboard reversal has been produced by opto-mechanical means. This paper presents the results of using a television display as the stimulus generator, and some of the advantages of such a purely electronic source of pattern reversal are discussed.


Voltage clamp with double sucrose gap technique. External series resistance compensation. In this paper we deal with the double sucrose-gap voltage clamp technique. To perform a reliable clamp or to analyze the intracellular potential distribution, any external series resistance in the artificial node must be taken into account for it induces an instability in the external potential as soon as a current develops. A circuit was designed to compensate for this error, it has been found effective on an analog model and on experimental uni- or multicellular preparations. The attenuation in series resistance frequently causes ringing in the step response. This behavior was studied theoretically and also simulated with analog models where a selective bridged-T network was found to represent the electrical characteristics of the preparation when associated with the chamber and control electronics. A residual series resistance was found and is considered to be a part of the preparation. Characteristics necessary to obtain best results are proposed, for a preparation to be studied in experiments utilizing the double sucrose gap technique with external series resistance compensation.


Theoretical model of the ionic mechanism of 1/f noise in nerve membrane. A model is presented for the ionic mechanism of low frequency 1/f electrical noise which has been observed in axonal membranes. The model consists of narrow channels which open randomly throughout the membrane and remain open for only a short time compared with f-1max where fmax approximately 2 kHz is the maximum frequency for which 1/f noise is observed. The fluctuation in channel formation is coupled to low frequency normal mode vibrations in liquid crystals which have properties similar to nerve membranes. Ionic current flow through the channels is assumed to occur via single file diffusion. The diffusion process is regarded as a non-Markovian random walk on a one-dimensional lattice which is mathematically decomposed into its spatial and temporal components. This technique allows calculation of the mean and variance of the number of ions which flow through any single short-lived channel. The final result for the current noise power spectrum, S, is S(f) = (A + k/I/2)/f, where I is the mean membrane current and A and k are parameters which are independent of membrane voltage. The theoretical result is consistent with observations of 1/f noise in lobster axon by Poussart (1971, Biophys. J. 11:212.) on the dependence of S(f) on the mean steady-state current and the external potassium concentration. We also calculate the mean channel density and the Frank elastic constant of the membrane. This work is an extension of a macroscopic model of Lundström and McQueen (1974, J. Theor. Biol. 45:405.) who obtain a spectral density of the form S approximately /I/2/f.


Electrical properties of the squid axon sheath. The first impedance data on the squid giant axon gave a lossy membrane capacity of 1 muF/cm2 from 1-200 kHz. The remaining observations of one experiment up to 5 MHz were not included in the simple conclusions and have now been ascribed to the mostly Schwann cell sheath. The results of these fragmentary data, 1.6 omega-cm2 and 12.5 membrane layers, are within the range of recent current clamp and electron microscope conclusions to give them independent confirmation and support.


Blocking of valinomycin-mediated bilayer membrane conductance by substituted benzimidazoles. Valinomycin selectively transports alkali cations, e.g. potassium ions, across lipid bilayer membranes. The blocking of this carrier-mediated transport by four substituted benzimidazoles has been investigated. The compounds are 4,5,6,7-tetrachloro-2-trifluoromethylbenzimidazole, (TTFB); 4,5,6,7,-tetrachloro-2-methylbenzimidazole, (TMB); 2-trifluoromethylbenzimidazole, (TFB); and 2-methylbenzimidazole, (MBM). Because of its low acidic dissociation constant (pKa = 5.04), the blocking efficiency of TTFB in both neutral and anionic forms in the aqueous phase could be studied. The compounds exhibit the blocking efficiency sequence, TTFB- greater than TTFB0 greater than TMB0 greater than TFB0 greater than MBM0. The corresponding scale of decreasing lipophilicity, as determined by octanol/water partitioning, is TTFB0 greater than TMB0 greater than TTFB- greater than TFB0 greater than MBM0. Comparison of neutral species establishes a positive correlation of blocking efficiency with lipophilicity, with the latter being conferred primarily by chlorination of the benzenoid nucleus. Anionic TTFB, on the other hand, is the most effective blocking agent studied in spite of the fact that its dissociation in the aqueous phase markedly impedes its entry (presumably as a neutral species) into a bulk hydrocarbon phase. This observation suggests that the blocking of valinomycin-mediated bilayer membrane conductance takes place at the membrane/solution interface.


Swimming of flagellated microorganisms.

Swimming of flagellated microorganisms. The swimming motion of a microorganism with a single flagellum is investigated for both helical and planar flagellar motion. First the force and torque exerted on the organism by the surrounding fluid are calculated in terms of the specified flagellar motion and the unknown linear and angular velocity of the whole organism. Then these unknown velocities are determined by the condition that the net force and torque on the organism are zero. Using these velocities, the trajectory of the organism is found. In the case of helical flagellar motion, the path of the entire organism is found to be a helix of small radius. The axis of the flagellum is not parallel to the axis of the helical path, but makes a small angle with it and precesses around it. If the flagellar motion is planar and sinusoidal, then the trajectory of the organism is found to be a straight line with small oscillations about it. Each point of the flagellum also oscillates longitudinally with double the frequency of the transverse oscillation, producing a figure eight motion. However if the flagellar motion is planar and asymmetric, then the trajectory is found to be a circle with small superposed oscillations. These conclusions account for the observed helical and circular trajectories of sperm, and for the figure eight motion of the tip of the flagellum in the planar case.


A kinetic model for the sodium conductance system in squid axon. We describe a kinetic reaction sequence for the sodium conductance system in the squid axon. It closely matches the original Hodgkin and Huxley model for voltage clamp experiments but it generates an action potential without a bump on the falling phase. When calcium ions are included in the reaction, this model faithfully reproduces the experimental observations of Frankenhaeuser and Hodgkin  on the effects of altered calcium in the medium. The fit to experiment is much better than when a voltage shift in rate constants is assumed. The gating currents recently observed by Armstrong and Bezanilla are not compatible with the Hodgkin and Huxley model but can be reprocuced in considerable detail by the kinetic model. Thus it appears that the kinetic model differs from that of Hodgkin and Huxley perhaps in an important and fundamental way that makes it more realistic.


Studies of light emission, absorption and energy transfer in nerve membranes labelled with fluorescent probes. Physicochemical properties of fluorescent membrane probes, 2-p-Cl-anilinonaphthalene-6-sulfonate (p-Cl-ANS), 2-p-Br-anilinonaphthalene-6-sulfonate (p-Br-ANS), merocyanine-540, methyl violet, etc., were examined because of the possibility of demonstrating resonance energy-transfer between probes. The emission psectra of p-Cl-ANS and p-Br-ANS and the absorption (or fluorescence excitation) spectra of Eastman Kodak merocyanine-540 (M-540) and other probes were found to be very sensitive to changes in the solvent polarity. The spectra of these probes incorporated in the nerve membrane were determined and compared with the corresponding spectra in various organic solvents and macromolecules. This comparison suggests that the polarity of the binding sites for p-Cl-ANS (and p-Br-ANS) in the membrane is high and that of M-540 is very low. The spectrum of the portion of p-Cl-ANS fluorescence contributing to production of optical responses (i.e., transient changes during action potentials) was determined. Both absorption responses and fluorescence responses were detected from M-540 in the nerve membrane. It was possible to demonstrate resonance transfer of electronic energy from p-Cl-ANS to M-540 incorporated in lysolecithin micelles and in crab nerves. During action potentials, the intensity of M-540 fluorescence excited by energy transfer was found to undergo transient changes. Based on these and other experimental findings, properties of the binding sites for these probes in the nerve membranes are discussed.


Thermodynamic investigations of proteins. II. Calorimetric study of lysozyme denaturation by guanidine hydrochloride. The thermodynamic parameters of the denaturation of lysozyme are determined at various temperatures (25-60 degrees C) by isothermal calorimetric titrations with guanidine hydrochloride (GuHCl) and by scanning calorimetry in the presence of GuHCl. An approach for the determination of the enthalpy of preferential binding of GuHCl is proposed. It has been shown from GuHCl denaturation experiments that the net enthalpies of denaturation and the denaturational change in the heat capacity of protein can be obtained if preferential binding is taken into consideration. These results are nearly the same as in the case of thermal denaturation in the absence of denaturants. It is concluded that the states of both heat- and GuHCl-denatured lysozyme are thermodynamically indistinguishable.


Radial migration of DNA molecules in cylindrical flow. III. Circles and the effect of non-gaussian polymer statistics. We have previously shown that DNA will migrate radially inward in a concentric-cylinder shear flow apparatus. We assumed gaussian chain statistics, and we considered only linear molecules. In this paper, we extend the analysis to closed circular molecules, and we consider non-gaussian statistics for both linears and circles. We find that, in good solvents, the inward radial migration velocity is more sensitive to the molecular weight than M5/2, which we previously reported for gaussian chains. Furthermore, linears migrate radially inward 8 times faster than do circles of the same molecular weight. This suggests the possibility of separating linear from circular DNA in solution.


Dynamical theory of fluorescence polarization in a planar array of oriented pigment molecules. A theory is developed appropriate for the analysis of fluorescence polarization experiments with pigment molecules in a planar array (plane membrane). Especially rotatory and oscillatory dynamics of the pigment molecules are considered. Three model calculations are performed, which describe the following different situations: (a) Rotational diffusion of molecules around the normal to the plane membrane. (b) Oscillatory diffusion of molecules with respect to this normal. (c) As a two-dimensional example the independent superposition of both types of motion. Central point of these model calculations is the determination of an intensity of emission function, from which in practical application the measured fluorescence intensities may uniquely be calculated.


The use of sedimentation coefficients to distinguish between models for protein oligomers. The sedimentation coefficients of proteins are dependent on their sizes, shapes and densities and on the density and viscosity of the solvent. However, when the sedimentation coefficients of an oligomeric protein and its protomer are measured under the same experimental conditions, the ratio of the two coefficients depends only on the protomer shape and the mode of aggregation. This property, which we shall call the sedimentation ratio, therefore provides a way of distinguishing between models for oligomeric proteins. To allow examination of the behaviour of the sedimentation ratio, sedimentation coefficients are calculated for a comprehensive range of protomer shapes and modes of aggregation in hexameric systems using equations derived by Kirkwood. As illustrations of the method the resulting sedimentation ratios are compared with experimental values for insulin and arthroped hemocyanin, which eliminates many of the possible structures for these proteins. When experimental estimates of degree of hydration and molecular dimensions are also considered, all but a group of virtually identical structures are eliminated for the insulin hexamer and a single most likely structure remains for arthropod hemocyanin. The insulin structure is in good agreement with that determined by X-ray crystallography while the hemocyanin hexameric structure is a hexagonal prism formed by the cyclic aggregation of prolate ellipsoids of axial ratio about 2.5 : 1.


Combined external and internal mass transfer effects in heterogeneous (enzyme) catalysis. A graphical method is outlined in order to calculate the conversion under combined intra- and extraparticle transport limitations using the existing effectiveness factor charts for intraparticle diffusion. This method is applied to the case of an immobilized enzyme, assuming that the kinetics are of the Michaelis-Menten type.


Temperature dependence of a diffusion-limited immobilized enzyme reaction. The apparent activation energy of N-alpha-benzoyl-L-arginine-ethyl ester (BAEE) hydrolysis by immobilized trypsin varies with the bulk substrate concentration from its maximum value, comparable to that of the free enzyme, to considerably lower values. Thus, with a concentration change from 3 x 10(-2) to 10(-4) M the apparent activation energy diminishes from 9.5 to 4.5 kcal/mol. This experimental finding is interpreted to be due to Michaelis-type kinetics in a heterogeneous system, in one case reflecting the temperature dependence of the maximal enzyme reaction rate, in another case illustrating the diffusion limited overall reaction at low substrate concentrations. As a consequence it may not be feasible to operate a reaction at elevated temperatures in a high conversion range, since diffusion limitation may restrict the enhancement of the overall reaction rate. Some further data are given concerning the buffer effect on the reaction rate, which should occur due to its limitation by proton transfer in the buffer-free system.


[The effect of biologically active substances (acetylcholine, histamine and bradykinin) on depolarization of taenia coli smooth muscle]. In experiments on the isolated strips of Taenia coli of guinea pigs it was shown that compound D-600 depressed the acetylcholine (5-10(-6), histamine (2-10(-6) and bradykinin (10(-5) gl/ml)-induced contractile response of depolarized smooth muscle. Along with depression of the drug-induced response, compound D-600 depressed the "potassium contracture". It is supposed that the mentioned agents activated the inward flow of Ca2+ ions through the membrane, but not the release of these ions from the sarcoplasmic reticulum.


[Motor reactions and cardiac activity of the fetus at the end of full-term pregnancy and during labor]. There are two forms of motor activity of the skeletal muscles at the last stages of internatal ontogenesis, i. e. jerky (jMA) and prolonged (PMA). Vagal regulation of the cardiac activity of the fetus associated with development of temporary hypoxemia took place before and after the JMA and the PMA. JMA and PMA occurred during labour pains when the circulation in the uterus decreased and development of JMA and PMA resulted in the compensation of temporary fetal hypoxemia.


[Modeling microcirculatory disorders using an ultraviolet laser]. Reactions of microvessels and mast cells to laser irradiation were studied in rat mesentery by applying the method of intravital microscopy. An ultra-violet laser (gamma=337 nm) was used. The diameter of the laser beam was changed from 2 to 100 mum. Different irradiation doses provoked either an increase of vascular permeability or thrombus formation or hemorrhage. Apart from the vascular wall injury, factors accompanying the damage of red blood cells and other cells of the blood may play a role in the process of thrombus formation. Changes of the vascular diameter and permeability after laser irradiation of mast cells are probably connected with the release of histamine and serotonin contained in them.


[Photogenic epilepsy with localization of the generator of excitation in the lateral geniculate body (the phenomenon of a determining dispatch station)]. The photogenic seizure syndrome was produced in experiments on rats and cats by injection of purified tetanus toxin into the lateral geniculate body (LGB). The seizures followed light stimulus or arose spontaneously. At the intervals between the attacks every light stimulus provoked a specific photojerk. Disturbance of the inhibitory mechanisms by tetanus toxin proved to result in a rise in the LGB of a generator of pathologically enhanced excitation underlying the hyperactive determinative dispatch station causing the described photogenic epilepsy.


[Changes in the acetylcholine--cholinesterase system in the dynamics of experimental boltulin poisoning]. A study was made of the effect of botulin, type B, on the acetylcholine-cholinesterase system. High doses of the toxin increased the level of acetylcholine in the peripheral blood nervous system, as well as in the central nervous system. Injection of DLM of the toxin results in elevation of the acetylcholine level in the peripheral nervous system. Cholinesterase activity was practically unchanged.


[Microcirculatory changes in poisoning by phosphoorganic cholinesterase inhibitors]. Experiments were conducted on rats and rabbits; a quantitative study was made of the microcirculation, of some indices of gaseous exchange and of the acid-base balance of the blood in poisoning with phosphorus organic cholinesterase inhibitors of peripheral action GA-70. The results obtained were compared and microcirculation disturbances were found to play the leading role in the GA-70-hypoxia developing in intoxication.


[Electrographic manifestations of "falling asleep" in isolated cat cortex]. Experiments were conducted on unrestricted cats; a study was made of the electrical activity of the neuronally isolated cortex during the wakeful hours and sleep. Transition from wakefulness to sleep was accompanied in the isolated cortex by the manifestations of drowsiness accompanied by the corresponding changes in the electrocorticogram of the isolated hemisphere. Electrographic manifestation of drowsiness in the isolated cortex depended on the time lapse after the operation and was mostly pronounced during the late period after the isolation of the cortex.


[Bronchial wedge pressure in experimental pulmonary emphysema]. The work of breathing and its subdivisions, pulmonary compliance, the bronchial wedge pressure, intrapleural and esophageal pressures were measured in 8 normal rabbits and in 15 rabbits with emphysema induced by intravenous injections of licopodium spores. Investigations were carried out under intravenous thiopenthal anesthesia. In normal rabbits the amplitude of the bronchial wedge pressure was on the average twice as great as the pleural and esophageal pressures.


[The influence of natural inhibitors of radical reactions on autooxidation of adrenaline]. In the presence of EDTA soluble antioxidants (1 muM reduced glutathion, 3 muM cystein, 1 muM ascorbic acid) inhibited the autoxidation of epinephrine at pH 10.2; as to alpha-tocopherol (40 muM) and the oxidative forms of these antioxidants - they were ineffective. The inhibitory effect of superoxide dismutase was much greater than that of the antioxidants testsd. The appearance of adrenochrome during the free radical autoxidation of epinephrine proceeded without any participation of the hydroxyl radical.


[Use of Na1C14 acetate for biosynthesis of serum and organ lipid components in the early periods of experimental myocardial ischemia]. The use of 1C-14 acetate for biosynthesis of lipids and their fractions (cholesterol, phospholipids, triglycerides and nonesterified fatty acids) in the heart, liver, adrenals, lipoid tissue and blood serum was studied in experimental myocardial infarction on the 5th to the 30th day of the experiment. It was concluded that disturbances of lipid metabolism did not always precede myocardial infarction and acute myocardial ischemia could induce changes in lipid metabolism characteristic of atherosclerosis.


[Succinate dehydrogenase activity of isolated myocardial mitochondria during chronic insufficiency]. Succinic dehydrogenase (SDH) activity of the isolated mitochondria myocardial cells in chronic cardiac insufficiency was studied experimentally. The highest SDH values were found in the mitochondria of condensed type. The activity of the enzyme was low in the ordinary (orthodox) mitochondria. The medium SDH activity was registered in the intermediary type of mitochondria. The ordinary and the intermediary types of mitochondria prevailed in the fraction under study reflecting a fall of the SDH activity in the myocardial tissue. Biochemical study of the mitochondrial fraction revealed a slight dissociation between the tissue respiration and the oxidative phosphorilation. The low SDH activity values seen to indicatate the state of overstrain of the energy-producing structures.


[A neurophysiologic analysis of the effect of amidopyrine at the thalamo-cortical level of the somatosensory system]. Acute experiments were conducted on nonanesthetized cats; it was shown that amidopyrin (10, 20 mg/kg, intravenously) decreased the level of the background activity of the thalamic neurons, and, at the same time, increased the amplitude of the focal primary bioelectrical reactions. It is supposed that amidopyrin synchronized evoked reactions of the cells in the thalamus, as well as in the cortex. On the other hand, amidopyrin diminished the excitability of the cortical neurons participating in the interzonal connections.


[The effect of neurotropic substances on the self-stimulation reaction at the thalamic level]. The effect of d-amphetamine, cocaine, caffeine, morphine, imipramine, phenobarbital, LSD-25, benactyzine, meprobamate, diazepam, chloridiazepoxide on the lateral hypothalamic self-stimulation of rats was investigated. D-amphetamine, cocaine, caffeine, morphine, imipramine decreased the threshold of selfstimulation. Meprobamate, diazepam, chlordiazepoxide failed to influence this index, but increase the intensity of self-stimulation during the threshold, the optimum and more than the optimum cirrent intensity. Benactyzine, LSD-25, phenobarbital decreased the threshold and increased the frequency of self-stimulation during all the current intensities. A comparative study of the above results showed the agents of the first group to exert a direct stimulating action on the positive reinforcement system. Tranquillizers activated this system due to their depressive action on the negative reinforcement system. Benactyzine, LSD-25, phenobarbital activated the system and depressed the system of negative reinforcement.


[Different sensitivities of cerebral arterial systems to noradrenaline]. The tests carried out on the nonanesthetized and anesthetized cats showed noradrenaline to exert a direct influence on the cerebral vessels, increasing their tone. The drug produced different effect on the vessels of different arterial systems of the brain. Noradrenaline increased the resistance of the carotid arteries to a greater degree than in the vertebral arterial system.


[Serotonin uptake by human thrombocytes as a method of screening antidepressants]. Imipromine-like antidepressants (10(-7)--10(-5) M) significantly inhibited the uptake of serotonin by the human blood platelets. Among the neuroleptics haloperidol alone depressed the uptake of serotonin in the concentration of 10(-5) M. Amphetamine and cholinolytics failed to affect the uptake of serotonin even in a concentration of 10(-4) M. The data obtained supported the hypothesis on mediation of the thymoanaleptic action through the intensification of the central serotoninergic processes. Serotonin uptake by the human blood platelets can be used for screening the antidepressants.


[The comparative effects of actinomycin D, imuren and hydrocortisone on interferon and antibody formation in mice]. A single dose of actinomycin-D (2.5 mg/kg body wt) reduced the interferon formation 16-fold in comparison with control; as to the antibody production - it was completely abolished. Hydrocortiosone (100 mg/kg) also diminished the interferon production 16-fold, but had no effect on the production of antibodies against the virus. The effect of hydrocortisone on the antiviral immunity was similar to that of the antilymphocytic serum, whereas the action of actinomycin-D resembled the effect of the X-ray irradiation or imuran. The data obtained were consistent with the suggestion on the heterogeneity of cells, participating in the interferon production in the organism.


[The relationship between the doubling time of human lung tumor volume and the labelling index]. The value of the labelling index (incubation with H3-thymidine) was compared with the doubling time of tumour volume (by repeated roentgenograms) for 3 tumours of human lungs: two squamous cell carcinomas taken at various differentiation levels and a hamartoma. The minimum doubling time (178 days) was shown for the squamous cell carcinoma with a lower differentiation level and the greatest labelling index value (19.0%). Hamartoma (a non-malignant tumour of lung) displayed the longest doubling time (1250 days) and the least labelling index value (3.8%).


[The effect of several neurotropic preparations on the differential character of pancreatic enzyme secretion]. Chronic experiments were conducted on dogs with pancreatic fistulae; secretion of the pancreas (basal and stimulated by duodenal perfusion by acid solutions, albumin and its polypeptide hydrolysate) was investigated with consideration to its enzyme (amylase, trypsin, chymotrypsin) secretion. The polypeptide hydrolysate proved to stimulate the pancreatic enzymes more than pure protein. Barbamyl, chlorpromazine and amyzyl inhibited both the basal and the stimulated secretion of the pancreas. The differential character of the pancreatic enzyme secretion was most disturbed by chlorpromazine and amizyl; this served as an evidence of the substantial role of the central adrenergic and cholinergic structures in the adaptation of the pancreatic secretion to food stimuli.


[Proliferative activity of the epithelium of the rat large intestine during carcinogenesis]. Labelling index and mitotic regimen in the epithelium of the rat descending colon and the ileum was studied during the tumour induction with 1,2-dimethylhydrazine. One month after the beginning of the experiments there was a marked increase of abnormal mitoses (up to 51%) and a change in the proportion of the mitotic phases with the metaphase prevalence (up to 73%). Later, these parameters were unchanged. Beginning from the 3rd month of the experiment there was found an increase in the labelling index (especially, in the carcinoma in situ) and of the mitotic index. In the mucosa of the ileum (where the tumours never developed) no changes of the proliferative activity and of mitotic regimen were found.


[Thyroid regeneration in dogs following its resection]. Experiments were conducted on 40 dogs; one lobe of teh thyroid gland or one lobe and 2/3 of the other lobe were removed. There was no gain in weight of the remaining lobe, or of the residue of the gland's lobe. Recovery of the thyroid gland function by hypertrophy of the thyroid epithelium in its remaining portion was achieved by hyperplasia of the intracellular structures.


[The effect of hydrocortisone on DNA synthesis by sebaceous gland epithelial cells]. The autoradiography method demonstrated a single injection of hydrocortisone (10 mg per 100 g of body weight) to result in suppression of the cell transition from the G1 phase of the mitotic cycle to the S phase and in prolongation of the S phase of the epithelium of the acinar portion (sebocytes) and stratified epithelium of the excretory ducts of the sebaceous gland of rats. Later, after a decrease of the proliferative processes by hydrocortisone there occurred their increase which was higher than control. Hydrocortisone induced a more pronounced effect on the proliferative activity of the stratified epithelium of the excretory ducts than on the sebocytes of the acini.


[The radiosensitivity and direction of differentiation of splenic colony forming cells]. Radiosensitivity of spleen CFU localized in the bone marrow and in the spleen proved to be the same. Do is about 105--120r for the CFU-forming colonies in the spleen and 120--135r for the CFU-forming colonies in the bone marrow. As suggested, there are two CFU fractions in the bone marrow. One of them is radiosensitive and another--radio-resistant. Chiefly the radiosensitive CFU fraction is the one localized in the spleen.


[Study of human chromosome reproduction time using 5-bromdeoxyuridine]. 5-Bromodeoxyuridine (BDU) -- 20 gamma/ml, 5-fluorodeoxyuridine (FDU) -- 0.1 gamma/ml and uridine -- 3 gamma/ml were introduced into the lymphocyte cultures of the peripheral blood of normal persons of both sexes. Chromosome preparations were prepared in 5 hours they were stained after the incubation in the fluorochrome solution Hoechstt 33258 with a 2% Giemsa solution on phosphate buffer (pH -- 5.0). Chromosome areas with incorporated BDU stained with Giensa solution but weakly; because of this regions with late replication were seen in each chromosome in thr form of weakly stained segments. A picture of late DNA replication is described on the basis of this method in all human chromosomes.


[The morphologic basis for asynchronous secretion by pancreatic cells]. Electron microscopic study of the pancreas of the vertebrates showed that asynchronous secretion of the pancreatic cells was regulated by means of the cytoplasmic extrusion. The latter provided selective entrance of the initial substances from the pericapillary spaces into the cells. Cytoplasmic extrusion also regulated the passage of the hormonal and other metabolites from the intercellular spaces into the pericapillary space.


[The role of adrenergic structures in the control of cerebral circulation]. A study of the cerebral blood flow carried out by the thermoelectric method demonstrated that stimulation of the cervical sympathetic nerve led to marked changes in the cerebral blood supply. The blood flow changes were two-stage in character: an initial slight increase changed to a decrease below the initial level. Pharmacological analysis with the use of alpha- and beta-adrenoblockers showed a constrictor reaction of the cerebral vessels to be caused by excitation of the alpha-adrenoreactive structures, and the dilatator reaction - by the beta-adrenoreactive structures. An opinion is put forward on a possible mechanism of these changes.


[Assessment of th- quantity of mast cells in the organs of the gastrointestinal tract of rats and frogs]. A method of evaluation of mast cell concentration in which all the tissues of an organ are included gives statistically significant figures. This method showed mast cell concentration in the digestive tract organs of rats and frogs to be a fixed value within a morphofunctional zone. In the tongue the mast cell concentration was the same both along its length and in the symmetrical parts of the organ. The concentration of mast cells diminished considerably from the tongue, the duodenum and down to the stomach.


Contractile system function in mammalian smooth muscle. The literature on the classical mechanical properties of geometrically simple mammaliam smooth muscle preparations is analyzed in an attempt to characterize the contractile system. Although the physiological behavior of smooth muscle is diverse, indices of contractile system function suggest there is considerable uniformity at this level. Compared to vertebrate striated muscles, smooth muscle tissues and possibly individual cells (i) often develop equal or greater maximum isometric force/cell cross-sectional area, with (ii) low and fairly uniform maximum shortening velocities, and (iii) operate over a range of lengths which may be no greater than the potential in striated muscle. Few details are known of filament structure, organization, interactions, and of force transmission in comparison with the extensive information on the contractile unit (sarcomere) for striated muscle. Consequently, tissue or cellular mechanical parameters may not be directly proportional to the output of the myofilamental contractile unit smooth muscle. A sliding filament mechanism involving actin-myosin interactions qualitatively similar to those in striated muscle seems probable. However, there are important quantitative differences in the contractile, apparatus which may be related to functional properties.


An autoradiographic and pathological study of cellular proliferation in rabbit arteries correlated with an increase in arterial pressure. Following partial constriction of the abdominal aorta, and the increase in arterial pressure in vessels proximal to the ligature at 3, 6, 14, 21, and 28 days was correlated with pathological changes and with proliferation of cells in the arterial wall measured by 3H-thymidine labeling indices and mitotic counts. The time course of arterial pressure rise and vascular smooth muscle cell proliferation were similar. Patterns of proliferation of cells of the artery wall varied in distribution with time, the presence of absence of traumatic changes seen by light microscopy, and the histological structure of the vessel. Arteries not subject to hypertension did not differ from sham-operated animals.


Digital artery blood flow and digital pad opacity during vasoconstriction. Digital artery blood flows were compared with digital pad opacity pulse amplitudes in dogs during vasoconstrictor responses. A high correlation between digital artery flow and opacity pulse amplitudes occurred during infusions of epinephrine and sciatic and tibial nerve stimulations, but not during superficial fibular nerve stimulation. The results confirmed earlier findings that tibial nerve stimulation produced predominantly precapillary constriction, and that superficial fibular nerve stimulation produced predominantly postcapillary constriction. Events in precapillary vessels appeared to be responsible for the opacity pulse. This fact probably forms the basis for the close relationship between opacity pulse amplitude and blood flow.


Rat aortic histamine synthesis during short-term hypertension. Thoracic aortic histamine synthesis has been examined in rats rendered hypertensive for periods ranging from 1/4 to 8 days through ligation of abdominal aorta between origins of the renal arteries, in a preliminary attempt to establish whether activity of the aortic nonmast-cell histidine decarboxylase system is increased in experimental hypertension. Results indicate that aortic histamine synthesis is increased 66, 75, 96 and 55% at postsurgical intervals of 1/4, 1/2, 1 and 8 days. These data suggest at least one biochemical explanation for both increased arterial wall permeability and the arterial inflammation consistently associated with both clinical and experimental hypertension by resolving these into those associated with the prolonged inflammatory response.


Stress relaxation in hog carotid artery as related to contractile activity. The purpose of this work was to test the hypothesis that stress relaxation (SR) in vascular smooth muscle is related to the amount of contractile activity (developed stress) and perhaps a property of the contractile element (CE). Using medial-intimal strips from the hog carotid artery, a strain (delta 1/l0, where l0 equals optimal length for force development) of 2% was applied at two different rates in the presence of various levels of developed or passive stress. Developed stress was altered either by changing the extracellular K-ion concentration with the strip length equal to l0 or by stimulating with a salt solution containing 30 mM KCl at various strip lengths. Passive stress was altered by varying strip length. At each level of developed or passive stress the magnitude of the increment in stress due to the strain (induced stress) and the SR were noted. SR varied directly with the magnitude of the developed stress, but there was a small and relatively unchanging amount of SR when passive stress was varied. At a given level of developed stress, the magnitude of SR was greater at a strain rate of 0.016 than at 0.001 l0/sec. When developed stress was altered, the magnitude of SR was essentially equal to the amount of induced stress; however, when passive stress was varied, SR was always less than induced stress. These observations are consistent with the hypothesis that, in the presence of developed stress, a large fraction of the SR represents the lengthening of the CE. This increased CE length allows a reequilibration of stress between the series elastic element and the contractile element. In the absence of developed stress, SR may represent a passive, physical property of this heterogeneous tissue.


Depression by local cooling of 3H-norepinephrine release evoked by nerve stimulation in cutaneous veins. Experiments were performed to investigate whether local cooling facilitates adrenergic neurotransmission in the cutaneous vein of the dog. Helical strips of saphenous veins were incubated with 3H-norepinephrine and mounted for isometric tension recording and superfusion. The superfusate was collected for measurement of total radioactivity or for chromatographic analysis. Electrical stimulation (2Hz) caused contraction and augmented the efflux of 3H-norepinephrine and metabolites. Cooling (from 37 to 28 degrees C) imposed during electrical stimulation caused a further increase in tension, but decreased the amount of 3H-norepinephrine and metabolites overflowing into the superfusate. These experiments demonstrate that the potentiating effect of cooling on the response of cutaneous veins to sympathetic nerve stimulation is not associated with facilitation of adrenergic neurotransmission. It is probably due to an altered sensitivity of the vascular smooth muscle to the transmitter.


[Immunoblastic lymphadenopathy with a pseudoleukemic blood picture]. The case of an immunoblastic lymphadenopathy with a leukaemoid reaction has been observed. All the clinical, serological and histological features described by previous authors were present. In addition, there were more than 1000000/mul nucleated peripheral cells, consisting of mature and a few immature granulocytes, a small number of normoblasts and many lymphocytes, "immunoblast-like" lymphoid cells and plasma cells. Polyclonality of the latter was demonstrated by serological methods. Spontaneous remission occurred and was apparently enhanced by the application of corticosteroids.


[Significance of photometric demonstration of variations in platelet form during aggregation caused by ADP: reality or artefact]. After a short theoretical recall concerning the problem of light scattering, the author presents some experimental studies about the variations of light intensity scattered by platelets during ADP induced aggregation. In contrast to the reports by Born and Michal, experimental demonstration is given, showing that these variations cannot be interpreted in term of shape change, as no theoretical basis supports these phenomea.


[Morphological phase-contrast cinematographic studies on the behavior of bone marrow cells in vitro. X. Myeloblasts and monoblasts]. The myeloblast is nearly of the same size as the lymphozyte and has the same nucleus cytoplasma ratio of 0.7 but differs from it in its morphology, its high frequency of multiplication, and by its kinetic behaviour. By phase contrast observation the transformation of the myeloblast into the promyelocyte has been seen several times. The myeloblast like the lymphocyte is able to move although at a much slower speed. By locomotion the myeloblast, and likewise the lymphocyte can move between blood and bone marrow. Of the granulocytopoietic series only the promyelocyte and the myelocyte with their nuclear cytoplasm relation of 0.3 are found in the bone marrow. The monoblast but is about twice its size, and moves less often. Apart from its transformation into promonocyte, monocyte and histiocyte, the monoblast may evalue in another way: it grows into a cell of doubled size with the same nucleus cytoplasm ratio 0.7 in whose cytoplasm are seen a lot of big granules. The cell may now be characterized as a tissue macrophage or mastcell. In consequence a frequently multiplying basophilic cell with a coarse nuclear structure and nucleoli, grows from a diameter of 6.5 to one of 13.0 mum without marked morphologic change apart from becoming alpha-NA-Esterase positive and acquiring big lysosomes. When this haemocytoblast is small (K 1/4 to K 1/2), it can be triggered into the granulocytopoietic series, when it is bigger (K 1/2 to K1) into the monocytopoietic series, or in the size K1 to K2 by erythropoietin into the erythropoietic series. If no triggering takes place, the cell degenerates after having granulated. The lymphopoietic system is not connected to this system of stem cells committed to the granulocytopoietic, the monocytopoietic and the erythropoietic series. Therefore we postulate a dual haematopoietic system. In acute leukemias the spread of size of cells and nuclei is wider and kinetically active stem cells are rarer. Only leukemic promyelocytes are in locomotion vividly, in contrast to the normal ones. In leukemic myeloblasts there are fewer mitoses than in normal ones, but in leukemic promyelocytes and monoblasts the mitotic frequency is not reduced.


[Harvesting of granulocytes for granulocyte transfusion by means of continuous flow centrifugation or filtration leukapheresis]. More than 10(10) viable granulocytes are necessary for a therapeutical effective granulocyte transfusion. This number of cells can be harvested from normal donors by two techniques basing on different principles: continuous flow centrifugation (CFC) and filtration leucapheresis (FL). Our studies demonstrated that, under certain special conditions, the separation potentials of both methods are comparable yielding 2.5 to 3.0 X 10(10) granulocytes within 4 hrs. Granulocyte collection rate was optimal if donors were treated with dexamethasone during 16 hrs prior to the state of the procedure. However, the costs of CFC exceed those of FL by a factor of about two. The increased occurrence of side effects attributed to the transfusion of FL-granulocytes can be reduced to the level of CFC-granulocytes by repetitive filtration-elution leucapheresis minimizing cell damage. The studies define the efficiency spectrum of CFC which in addition to granulocyte separation includes collection of thrombocytes, cells for immunotherapy, and plasmapheresis.


Automation--planning to implementation; the problems en route. Once the major decision to automate library processes is made, there are a variety of problems which may be encountered before the planned system becomes operational. These include problems of personnel, budget, procurement of adjunct services, institutional priorities, and manufacturing uncertainties. Actual and potential difficulties are discussed.


Medical serials control systems by computer--a state of the art review. A review of the problems encountered in serials control systems is followed by a description of some of the present-day attempts to solve these problems. Specific networks are described, notably PHILSOM (developed at Washington University School of Medicine Library), the UCLA Biomedical Library's system, and OCLC in Columbus, Ohio. Finally, the role of minicomputers in present and future developments is discussed, and some cautious guesses are made on future directions in the field.


Evolution of a processing system in a large biomedical library. The processing system used in the UCLA Biomedical Library is modest in size and still under development. Its origins date back to a batch mode serials control system begun in the mid-1960s. This was converted to an on-line system which currently has modules for check-in, updating and retrieval, claims, bindery preparation, and invoice information. Titles can be retrieved at the terminal by search of any word in the title, by subject heading, language, country of publication, and type of publication. The system is adaptable to network use and at present is shared with one other library. To the serials system has been added a computer-assisted cataloging and card production system. The latter utilizes serials nucleus software as well as design for data input and data storage. In-house listings and coding procedures overlap in a general way. Work is under way on further integration of the two processing subsystems and a feasibility study has been completed for addition of a subsystem for acquisitions which will combine and adapt features of the other two; for example, information retrieval characteristics from both, catalog coding and programs for acceptance of data, serials programs for claims, and other output programs. Cost benefits of the subsystems are described and discussed.


Computer-stored faculty publication file using the MT/ST in a medium-sized medical center library. The Bowman Gray School of Medicine Library has implemented a computerized faculty publication file adapted from an existing system that utilized a Magnetic Tape/Selectric Typewriter for catalog card production and computer storage. The faculty publication file has provided printouts for the school's annual report and monthly faculty bulletins. After the data for all faculty bibliographies have been stored in the file, it will be possible to retrieve complete author and departmental listings. The file will be continuously updated by adding current citations and the bibliographies of new faculty members and by deleting data when faculty members leave the staff.