Formation of microsomal cytochrome P-450 complexes studied by the NMR relaxation of water. Cytochrome P-450 in microsomes from liver of phenobarbital treated and control rats has been studied by light absorption and by magnetic resonance methods (EPR and NMR). The nuclear relaxation rate of water protons was measured for microsomal suspensions in the presence of various reactants of Type I and II. The change of relaxation rates correlates well with the spin state conversion of the heme iron. No competition between eventual inner-sphere water molecules and the reactants seems to occur. The temperature dependence of the low spin to high spin equilibrium was studied by light absorption and was accounted for in the temperature variation of the molar relaxation rates of the two spin states.


Raman spectroscopy: a structural probe of glycosaminoglycans. We report the first Raman spectroscopic study of the glycosaminoglycans chondroitin 4-sulfate, chondroitin 6-sulfate and hyaluronic acid, both in solution and in the solid state. To aid in spectral identification, infrared spectra were also recorded from films of these samples. Vibrational frequencies for important functional groups like the sulfate groups, glycosidic linkages, C-OH and the N-acetyl group can be identified from the Raman spectra. Certain differences in the spectra of the different glycosaminoglycans can be interpreted in terms of the geometry of the various substituents, while other differences can be related to differences in chemical composition.


Choice of an aqueous polymer two-phase system for cell partition. Partition of human erythrocytes in aqueous two-phase polymer systems produced by Ficoll and different molecular weight fractions of dextran and polyethylene glycol and the influence of the ionic composition on the cells' partition in the systems was studied. It is found that the Ficoll-dextran-40 system is characterized by a number of advantages as compared with the common dextran-polyethylene glycol system or the others systems under study. The main advantage of the system appears to be that it is possible to concentrate the red cells in the top phase or in the bottom phase of the system, depending on the system ionic composition. The influence of the nature and the concentration of salt additives on this two-phase system formation is examined.


Collagen synthesis by human glomerular cells in culture. Collagen synthesis was studied in three subcultured human glomerular cell types, by radiolabeled incorporation of [14C]proline and [3H]lysine. The epithelioid circular glomerular cells secrete a collagen with a single size of chain (possibly type IV) with a high ratio of hydroxyproline to proline, hydroxylysine to lysine, and 11--17% of hydroxyproline as the 3-isomer. The smooth muscle-like rhomboid glomerular cells secrete collagen with a chain pattern suggesting types III and I collagen, distinct from that found in the media of fibroblasts. Small ovoid glomerular cells are morphologically and biochemically intermediate between circular glomerular cells and rhomboid glomerular cells, and may represent an in vitro modification of either circular glomerular cells or rhomboid glomerular cells.


Kinetics of iron reduction of ferritin cores and of a low molecular weight hydroxy-iron polymer. The kinetics of reduction by dithionite of iron cores in ferritin and of iron cores after removal of the protein shell (isolated cores) has been analysed along with that of a low molecular weight hydroxy-iron polymer. Spectrophotometric measurements have shown that the time course of the reaction approximates a pseudo first-order behaviour. In the case of ferritin cores the pseudo first-order rate constant reaches an asymptotic value which markedly increases when the cores are isolated. In contrast, in the low molecular weight hydroxy-iron polymer, no clear asymptotic value is reached. Thus, the rate of reduction appears to be determined both by the presence of the protein shell and by the crystallite surface area. Kinetic light scattering experiments show that in ferritin and in the isolated cores a rapid drop in molecular weight occurs during the first stages of reduction, suggesting a fragmentation of the iron crystallite.


The role of polyamines in the regulation of AMP deaminase isozymes. The differential effects of polyamines on the activity of AMP deaminase isozyme A (from rat muscle) and isozyme B (from rat liver) are reported. Polyamines activate isozyme B but inhibit isozyme A.


UDP-N-acetylglucosamine-glycoprotein N-acetylglucosaminyltransferase in regenerating rat liver. The assay condition for N-acetylglucosaminyltransferase activities in rat liver microsomal fraction was developed. The enzyme activities towards endogenous acceptors within 48 h after partial hepatectomy were lower than in controls, exceeding the control level by 96 h, and then higher than in controls up to 240 h after the operation. The changes in N-acetylglucosaminyltransferase activities towards exogenous acceptor (UDP-2-acetamido-2-deoxy-D-glucose: glycoprotein 2-acetamido-2-deoxy-D-glucosyltransferase, EC 2.4.1.51) were consistent with those in the enzyme activities towards endogenous acceptors at 144 h, but not at 48 h, after the operation. The contents of protein and the levels of protein-bound hexosamine in the liver microsomes were decreased at early period of liver regeneration. These results suggest that the acceptor capacity of liver microsomal proteins is diminished during first 48 h of the regeneration. This may be responsible for the decreased transfer of the amino sugar to nascent glycoproteins. However, the enzyme activity was enhanced at 144 h and the level of endogenous acceptors may increase.


Change of the protein composition of the thyroid colloid during treatment with propylthiouracil and thyroxine: a microgel electrophoretic study of single rat thyroid follicles. Prophylthiouracil and thyroxine were given daily to rats for 4 weeks. Samples of colloid were collected in vivo from the superficial thyroid follicles during this period and their protein composition was analysed by gel electrophoresis. It was observed that the aggregates of thyroglobulin, i.e., the 27-S thyroid iodoprotein and the heavier fractions, were reduced to 50% after 1 week and were almost absent after 2 weeks. A faster migrating thyroglobulin fraction was observed in the samples of colloid and in the homogenate of the whole gland after 48 h of treatment. During the following period of treatment there was an increase in the relative amount of the faster migrating thyroglobulin fraction compared to 19-S thyroglobulin in the colloid, the former comprising approx. 75% of the globulins after 4 weeks, It can be concluded that propylthiouracil inhibits the formation of the 27-S iodoprotein and that a structurally altered and iodine-poor thyroglobulin fraction is accumulated in the follicle lumen.


[Mechanism of photoregeneration of reduced porphyrin in the presence of oxygen]. Photooxidation of reduced forms of porphyrines (IIH2) was studied. It has been shown that photooxidation of IIH2 is sensitized by initial porphyrine formed in the course of the reaction. Singlet oxygen serves as the basic oxidizer. It is also informed that the search of metastable states of photoreduced anion forms of the pigments by means of flashphotolysis turned to be unsuccessful.


[Mechanism of activation of the photosensitizing effect of water-soluble analogs of chlorophyll when bound to a polymer]. It has been shown that the order of mixture of photoreduction components of methylene red with ascorbic acid sensitized with clorine e in an aqueous solution of polyvinilpyrrolidone markedly affects the rate and depth of the reaction. The data obtained support the hypothesis that the intensificiation of the sensitized reaction in the presence of polymer is conditioned by joint polymer binding of the reaction components. This binding facilitates the interaction between the electron donor or acceptor with the light-excited pigment.


[Modification of phospholipid liposomes by electron dense labels]. Phosphatidilethanolamine (PE) of liposome was modified by electron-density label, trichlortriazin being used as an intermediate reagent. The electron microscopic study of pure PE liposomes has revealed the presence of typical lamellar structure which also has been visualized on PE liposomes modified by electron-density label. In case of liposomes which consist of PE and phosphatidilcholine cluster distribution of modified PE molecules was observed.


[Theory of the hypochromic effect in DNA]. A method for theoretical studies of hypochromism of natural DNA is presented. The DNA hypochromism changed in structural transitions of the helix-coil type is examined using the method developed. It is shown on E. coli DNA that the main cause of the DNA hypochromism increase during transitions from coil to helix is the change in intrastrans interactions connected with the strand ordering process.


[Effect of UV-light on formation of fluorescent products of lipid peroxidation]. The rate of fluorescent product formation during the peroxidation of polyunsaturated linolenic acid or egg phosphatidylethanolamine and also during the oxidation of linolenic acid together with a phenylalanine and synthetic phosphatidylethanolamine 1,5--3 times more intensive after previous UV-irradiation of the unsaturated fatty acid. Schiff bases are fluorescent products in amine containing systems which are produced in the reaction of the malonaldehyde with amines. It is possible that fluorochromes produced during the only unsaturated acid oxidation are the result of the radical recombination. Accumulation of the oxidated products determined by TBA-reactive substances does not inevitably correlate with the fluorescent intensity in explored systems.


[Role of calcium ions in stabilizing rat liver adhesion factor]. Highly purified native preparation of adhesion factor (AF) from rat liver was shown to inactivate after dialysis against deionised water or after action of chelating agent (EGTA). Isoelectric point of inactivated AF was less than 2.0 Rf value in PAG in presence of SDS was significantly increased. The results obtained suggest that inactivation of AF during electrofucusing depends on ampholyne binding of Ca(II) which may be constituent in AF.


[Resolution of the fluorescence and absorption spectra of chlorophyll a in the cell into its components]. The total number, band widths, absorption and fluorescence peak positions of universal forms of chlorophyll a in vivo were identified by means of computer curve analysis, Stepanov's relation and low temperature derivative spectroscopy. The identified pigment forms are as follows: Chl669(661), Chl676(674), Chl686(680), Chl691(687), Chl697(691), Chl706(698), Chl715(702) Chl726(709), Chl738(715) and Chl750--755(720--724) (the lower index--absorption peak position, the upper one--fluorescence peak position). The O--O electronic transitions vibronic bands energy one of the forms of chlorphyll alpha enumerated above changes for constant equal 140 cm--1.


[Translation mobility of water isolated in the cells of lyophilized Cryptococcus albidus var. diffluens yeasts by the NMR impulse method]. The method of NMR spin echo in a combination with the impulse gradient of the magnetic field was used to study the self-diffusion of water isolated in the cells of lyophylized Criptococcus. A relative fall of the amplitude of spin echo (factor R) in relation to the value of magnetic field impulse gradient (g), their duration (delta) and temporary distance between them (delta). The studies were carried out in the temperature range of 20 degrees divided by 80 degrees C. It has been shown that the fraction of isolated mobile water is located in intracellular permeable compartments with an average size of 0.6.10--4 cm at 20 degrees C. The coefficient of selfdiffusion of isolated water of Criptococcus (0.25.10--5 cm2S--1 at 20 degrees C) and the activation energy of selfdiffusion (4.4 ccal/mole at 20 degrees divided by 60 degrees C) were determined, permeability of walls of water-containing compartments taken into account.


[Mathematical model of the immune response. IV. Threshold character of the infectious process]. A model of immune reaction is described which takes into account the agressive behaviour of infectious microorganisms in the macroorganism. The model allows a description of threshold relationship between the infection process and the initial dose of the antigen. According to the model depending on the parameters and initial data the following regimes are possible: destruction of the antigen without a disease, its destruction after a disease, coexistence of the antigen with specific antibodies, recurrent course of the disease, unlimited multiplication of the antigen.


[Modeling the process of excitatory transmission from the mechanical portion of the auditory system to the nerve endings of the auditory nerve]. Sharpening of frequency selectivity of the mechanical part of the hearing system due to the transformation of the signals in the receptor system is investigated. It is proposed that excitation of neuron endings is proportional to the amplitude of the current which was produced by the difference of microphonic potentials in the neighbouring hair cells. It is shown that possible degree of the selectivity sharpening of the cochlea which can be explained by this model is in a good agreement with the known experimental results.


[Model of the light intensity analyzer]. The paper deals with coding the light intensity in visual analyzer. The single "neurons" of the proposed model have the properties of B-, D-neurons (primary detectors) [1] or the properties of so-called detectors of the light intensity [2]. Such "psychophysical" characteristics of the model as Stevens law, Weber fraction are in a good agreement with similar characteristics of the real visual analyzer.


[Relationship between the phase sensitivity of inferior colliculus neurons and the frequency of the acoustic signal]. With tone frequency (F) lower than the neuron characteristic frequency (F0), the neuron OFF-response is maximal at the signal end-phase (phi) of about 90 and 270 degrees and is minimal at about 0 and 180 degrees. On the contrary, with F less than F0 the OFF-response is maximal at phi-values of about 0 and 180 degrees and is minimal at about 90, 270 degrees. Considering these data as resulted by mechanical processes at the cochlear basilar membrane, it proved possible 1) to determine apriori the values of the OFF-responses to bitonal stimuli and 2) to predict different shift direction of the fused auditory image (in psychophysical experiment) with the phase change of one of the binaurally presented tones at frequencies lower and higher the human optimal sensitivity range.


[Criterion for determining the ionic specificity orders of membranes of biological and non-biological origin for univalent ions]. A formal criterion of membrane specificity for univalent ions is proposed: (see text), where Eg, El, and r stand for the energy of ion hydration, energy of ion interaction with the charged group (ligand) for the membrane, and ion crystalline radius respectively. Taking 5 cations: Li+, Na+, K+, Rb+, Cs+ as a model the existence of 16 lines of membrane ionic specificity out of 120 possible is predicted. On the basis of 4 anions: F--,Cl--,Br--,I--the existence of 8 lines out of 24 possible is predicted. 11 lines out of predicted cation lines and 7 out of anion lines were obtained by Eisenman.


[Mechanism of early receptor potential generation and an electrical model of retinal rods in rats]. A passive electric model of the retinal rod can reproduce the changes of the ELP-waveform at temperatures within the range 10 degrees--45 degrees C. R2-component of the ERP is generated by the process with the time constant ca. 500 microseconds (37 degrees C) and activation energy 31 kcal/mol characteristic of metarhodopsin I--metarhodopsin II transition. R1 originates not later than at prelumirhodopsin--lumirhodopsin conversion. Charge displacements are 0.006 (R1) and 0.04 (R2) electronic charges per rhodopsin bleached. The model is used for determining membrane capacitance and resistance of the rat retinal rod.


Primary structure of chicken erythrocyte histone H2A. The complete amino acid sequence (128 residues) of the chicken erythrocyte histone H2A was deduced from the data provided by structural studies on the tryptic peptides from the maleylated histone and of the peptides obtained by thermolysin digestion of the native protein. The sequence of chicken histone H2A differs from the calf homologous histone by the deletion of one residue of histidine at position 123 or 124 and three conservative substitutions: a residue of serine replaces a residue of threonine at position 16, a residue of aspartic acid replaces a residue of glutamic acid at position 121 and a residue of alanine replaces a residue of glycine at position 128.


RNA metabolism in M1 adrenergic neuroblastoma cells. RNA metabolism of M1 adrenergic neuroblastoma cells was investigated in logarithmic proliferating, stationary and differentiated states. [3h] uridine labelling experiments showed that in the stationary phase (10 days of culture) the cells incorporated less radioactive precursors into RNA than in the logarithmic phase (3 days of culture). Cells differentiated by bromodeoxyuridine treatment were compared with proliferating cells. At short labelling time, the BrdU-treated cells incorporated more [3H] uridine in RNA than the controls. But when morphological differentiation became irreversible, the treated cells incorporated less [3H] uridine into RNA. Our results show that morphological differentiation by BrdU-treatment of neuroblastoma M1 cells is not accompanied by striking changes in RNA metabolism.


Studies on the energy-linked Ca2+ accumulation in pig heart mitochondria - role of Mg2'ons. Comparative intracellular distribution of Ca2+, Mg2+ and adenine nucleotides has been studied in pig heart by differential centrifugation or fractional extraction and has shown that Mg2+ and ATP are associated mainly with soluble fractions whereas Ca2+ and ADP are more tightly bound to subcellular structures. Ca2+ accumulation and Ca2+ stimulated respiration were studied in pig heart mitochondria under different energetic conditions in the absence or presence of phosphate. Ca2+ concentrations of about 1200 nmoles/mg protein inhibit Ca2+ accumulation, site I substrate oxidation and induce an efflux of mitochondrial Mg2+. These deleterious effects of Ca2+ on respiration occur even in the absence of phosphate or oxidizable substrate; they are completely prevented by ruthenium red only, and partially prevented by the addition of M2+ to the medium. The kinetics of Ca2+ uptake become of the sigmoidal type when Mg2+ is present. This cation strongly inhibits the rate of Ca2+ uptake in the presence of added phosphate and decreases the affinity of Ca2+ for its transport system. In the absence of phosphate, Mg2+ has no effect on Ca2+ uptake. The possible physiological implications of these findings are discussed


Human serum hemopexin: direct evidence for change of its isoelectric point upon heme binding. A new serum protein fractionation. Human serum was submitted to a one step displacement-ligand exchange chromatography. Displacement removed serum albumin and part of gamma-globulins. Ligand exchange furnished an enriched heme-hemopexin fraction. An original, non denaturing human heme-hemopexin preparation is proposed.


[Relationship between calcium balance and electrogenesis of perfused rat liver]. The high level of intratissue electric cooperation enables to detect tissue potentials with microelectrodes thick enough to destroy individual cells. Nevertheless, in ordinary perfused rat liver, these "cooperative potentials" (CP) coincide in the magnitude with usual cell membrane potential (MP). Intercellular dissociations, however, cause appreciable differences in CPs at different scales. The data obtained show possible role of cytoplasmic calcium in primary control of hierarhic tissue integrity.


[Stabilization of flat bilayer lipid membranes by cholesterol]. Cholesterol is found to produce a stabilizing effect on bilayer lipid membranes (BLM) from alpha-monoglycerides of fatty acids and n-octan. The greatest stabilization effect is observed for alpha-monoglycerides, in which the length of hydrocarbon radical coincides with the length of cholesterol molecule. The life time of BLM from alpha-monolaurin, cholesterol and n-octan is measured in hours, and the tension of electric damage of the membrane reaches 860 mV.


[Adhesive stability of the ultrastructural elements of hepatocyte contacts]. A new method is suggested for the estimation of cell junction adhesion in the liver. It was shown that simple (spacing) junctions of hepatocytes consisted of low and high adhesive parts (sites). The hepatocyte junctions were positioned in the following sequence according to the increase of their adhesive durability; 1) low adhesive sites of simple junction and stude like junctions; 2) high adhesive sites of simple junction and desmosomes; 3) zonulae adherentes; 4) gap and tight junctions.


[Synthesis and activation of N-aminopolyacrylamide derivatives as carriers in solid phase degradation of proteins]. N-amino polyacrylamide derivatives were synthesized and their activation by different techniques were examined. The use of these derivatives as solid support in sequential degradation of proteins is proposed. An example is reported.


[Piezoeffect, baseline conductivity and filtration coefficients of lipid bilayer membrane]. A piezoeffect in bilayer lipid membranes (BLM), i.e. a generation of alternate electrical current y through a membrane under alternate pressure gradient in the absence of constant transmembrane potential is investigated. It is shown that y is not connected with the membrane deformations, it is generated with electroosmotic flow of K+ ions, its amplitude increases with a rise of BLM phonic conductance and is probably connected with defects in BLM structure. The value of the filtration coefficient Lp is estimated.


[Effect of redox properties of the medium on the thermoluminescence of the chloroplasts of higher plants]. The dependence of thermoluminescence characteristics of higher plants chloroplasts on the state of the electron transfer chain (ETC) was studied. The state of the ETC was changed with variation of the the redox state of the medium with different additions (mixture of ferri- and ferrocianide, DPIP, and DPIP in the presence of different concentrations of the ascorbate).


[Dynamics of temperature changes in tissues during laser irradiation]. Dynamics of heat wave propagation from irradiated surface into the tissue was studied. Computation of our results and those of other authors proved that temperature distribution against the tissue depth proceeds according to Buger law. Quenching coefficient values of the heat wave are calculated. This coefficient features more completely biophysical properties of the tissue, than the temperautre gradient. Tumour and pigmented tissues have a higher quenching coefficient of the heat wave as compared to normal and unpigmented tissues.


The hydrogen cycle in nitrogen-fixing Azotobacter chroococcum. H2 will support nitrogenase activity (C2H2 reduction) in Azotobacter chroococcum with or without added carbon substrate. Results show that H2 is metabolised to transfer electrons to nitrogenase and to the respiratory chain to produce ATP. H2-supported nitrogenase activity is most significant at low carbon substrate concentrations, but also occurs at saturating concentration. Continuous cultures of N2-fixing A. chroococcum evolved H2 from nitrogenase under O2-N2- and C-limited conditions. This H2 represented a significant proportion of nitrogenase activity. Hydrogenase activity was consistently high under C-limited conditions, but low or undetectable under O2- and N2-limitations. Pre-treatment with 40 per cent C2H2 inhibited hydrogenase activity in C-limited cultures, and H2 evolution increased under air and under Ar:O2 (4:1) mixtures. We deduce that hydrogenase : I, recycles H2 produced by nitrogenase to provide electrons and energy for N2 reduction: II, supports respiratory protection for nitrogenase under C-limited conditions, and III, does not act to prevent any inhibition of N2 reduction by H2 produced by nitrogenase. A scheme for the H2 cycle in N2-fixing A. chroococcum is proposed.


Nitrogenase--hydrogenase interrelationships in Rhizobia. A review is given of the properties of the hydrogenase present in Rhizobium bacteriods together with a discussion and evidence of the function of the enzyme in relationship to nitrogen fixation. The efficiency with which nodules fix nitrogen i.e. the amount of hydrogen evolved as a ratio of the total electron flow through nitrogenase, is considered and the recycling of hydrogen is discussed. Attention is drawn to recent work, in which plants which have nodules containing hydrogenase have been shown to fix more nitrogen and increase more in dry matter than plants with nodules without hydrogenase.


Membrane energization in relation with nitrogen fixation in Azotobacter vinelandii and Rhizobium leguminosarum bacteroids. Nitrogen fixation in A. vinelandii and R. leguminosarum bacteroides shows identical characteristics with respect to the dependence on membrane energization, the sensitivity to uncouplers, the ATP/ADP-ratio, and the dependences on flavodoxinhydroquinone as electrondonor. Although we have been successful in preparing inside-out vesicles which can be energized, attempts to couple these membranes to N2-ase were still unsuccessful. One of the major problems could be the failure to energize these vesicles directly by ATP. Although subject to polymerisation after addition of MgCl2, it could be shown that the actual mol.wt. of the O2-stable N2-ase complex is about 300,000 in agreement with a 1:1:1 stoichiometry of the three constituent proteins, namely, component I, component II and the 2Fe-2S protein.


Hydrogen metabolism and nitrogen fixation in wild type and Nif- mutants of Rhodopseudomonas acidophila. N2 fixation, C2H2 reduction and H2 production in Rhodopseudomonas acidophila DSM 137 were shown to be stoichiometrically related in ratios of 1:2.8:2.8. The highest possible H2 oxidation rate has been calculated to be about 6 fold higher in Rhodopseudomonas acidophila DSM 137 than the maximum rate of H2 production. Nif- mutants were isolated and tested; all of them had lost their ability of reduce C2H2 and to produce H2. In two nif- mutants hydrogenase activity and the capacity for autotrophic growth with H2 were also strongly diminished. Nif+ revertants not only regained their ability for C2H2 reduction and H2 production but also their full capacity for autotrophic growth with H2.


Hydrogen evolution by chloroplast-hydrogenase systems: improvements and additional observations. An in vitro system containing isolated chloroplasts, ferredoxin and bacterial hydrogenase on illumination evolves H2 and O2 from water. Maximum rate of hydrogen production so far achieved is two litres H2 per g. chlorophyll per h. The rate of H2 evolution per mg chlorophyll is dependent on concentrations of chlorophyll and ferredoxin in the reaction mixture. The rates as well as duration of H2 production are enhanced by the presence of oxygen scavengers and bovine serum albumin in the system. Hydrogenases and ferredoxins vary in their degree of cross reactivity in the chloroplast system; with some hydrogenases the H2 evolution rates were increased by the presence of additional biological electron carriers. Attempts to couple algal hydrogenases to the chloroplasts system have not succeeded so far.


Hydrogen metabolism in aerobic hydrogen-oxidizing bacteria. A survey on organisms able to use molecular hydrogen as electron donor in the energy-yielding process is presented. In the group of the aerobic hydrogen-oxidizing bacteria so far two types of hydrogenases have been encountered, a NAD-reducing, soluble enzyme (H2 : NAD oxidoreductase) and a membrane-bound enzyme unable to reduce pyridine nucleotides. With respect to the distribution of both types of hydrogenases three groups of hydrogen-oxidizing bacteria can be diffentiated containing (i) both types (Alcaligenes eutrophus), (ii) a soluble enzyme only (Nocardia opaca lb), and (iii) a membrane-bound hydrogenase only (majority of genera and species). The results of studies on the NAD-specific hydrogenase of A. eutrophus are summarized. Results on the solubilization and purification of the membrane-bound hydrogenase of A. eutrophus are presented in detail. The enzyme was solubilized from purified membranes by Triton X-100 and sodium desoxycholate or phospholipase D. The crude membrane extract was fractionated by ammonium sulfate precipitation and chromatography on carboxymethylcellulose at pH 5.5. The enzyme was stable in potassium phosphate buffer; it resembles the soluble enzyme with respect to stability under oxidizing conditions. Further biochemical and immunological data indicate, however, that both enzymes are different with respect to their native structure.


Reactivity of Desulfovibrio gigas hydrogenase toward artificial and natural electron donors or acceptors. A purified preparation of hydrogenase from D. gigas was inactive toward ferredoxin, flavodoxin or rubredoxin in the absence of cytochrome c3 (M.W. 13,000), in an atmosphere of hydrogen, although direct reduction of benzyl viologen or FMN was possible. The hydrogen evolution reaction from dithionite was possible with methyl viologen. The same reaction also occured with cytochrome c3 (M.W. 13,000) or cytochrome c3 (M.W. 26,000). Addition of either ferredoxin or flavodoxin did not accelerate the reaction.


Biofeedback training of 40-Hz EEG in humans. This study was a preliminary evaluation of biofeedback training of human subjects to control high-frequency EEG responses in the 35- to 45-Hz (40-Hz) and 21- to 31-Hz ranges. A total of 22 adult males divided into three groups were successfully trained for increases or suppression of 40-Hz EEG, or increases of 21- to 31-Hz EEG. Dissociation of rates of 40-Hz EEG recorded from scalp leads and 40-Hz EMG responses from prominent muscle contaminators, and partial dissociation of 40-Hz and 21- to 31-Hz EEG responses were noted. After biofeedback training, 8 subjects demonstrated increase and suppression of 40-Hz EEG without feedback. No consistent descriptors of subjective experiences accompanying EEG changes were reported by subjects in any of the groups. The study suggests the utility of biofeedback procedures in research on high-frequency EEG activity.


Behavioral and electroencephalographic correlates of 40-Hz EEG biofeedback training in humans. Two groups of eight adults successfully trained with biofeedback for increases in 40-Hz EEG responses in left or right hemispheres also demonstrated significant 40-Hz EEG increases during baseline periods, and increases in the contralateral hemisphere during training periods. No changes in heart rate, 40-Hz EMG, or 21- or 31-Hz beta, alpha, or theta EEG occurred over training days. Three subjects returning for additional training demonstrated suppression of 40-Hz EEG. A group of four subjects experiencing daily bidirectional training produced substantial within-session control of 40-Hz EEG but no changes over days. Data from posttraining tests without feedback for successful subjects in both groups indicated significant control of 40-Hz EEG responses in the initial parts of these sessions, and some correlated changes in other EEG responses. Measures of successful subjects' experiences during training and control tests indicated awareness of changes in subjective concomitants of EEG responses. This study suggests further strategies for research on behavioral correlates of EEG activity.


Discriminative control of the vaginal vasomotor response. With use of a discriminative control procedure and operant techniques, women significantly increased their vaginal pulse amplitude (produced vaginal vasodilation) but did not significantly decrease vaginal pulse amplitude (produce vaginal vasoconstriction). Acquisition of vaginal pulse amplitude control was rapid with no significant improvement over trials or the 5 experimental days. Specificity of vaginal pulse amplitude control occurred in relation to the other vasomotor responses, including vaginal blood volume and digital pulse amplitude. Vagnial pulse amplitude changes were not related to somatic-muscular, respiratory, or heart-rate changes. Women who used oral contraceptives were better able to control vaginal pulse amplitude than women who used other forms of birth control. Although the sexual behavior of these two groups and did not differ, women in the latter group tended to be more clitorally oriented.


Operant conditioning of skin resistance tonic levels. The purpose of the current investigation was to determine whether increases and decreases in skin resistance tonic level could be controlled by individuals given discrete visual feedback of such activity. Thirty-six male undergraduate students served as subjects. They were assigned randomly in equal numbers to four groups; two of the groups received accurate feedback of skin resistance level changes and two received inaccurate feedback. The two accurate-feedback groups differed with respect to the order in which increases and decreases in skin resistance level were reinforced. Each noncontingent group was matched with one of the contingent groups in terms of reinforcement density. The results indicated that accurate feedback produced skin resistance level changes consistent with the type of reinforcement employed. However, operant control was not clearly sustained subsequent to a reversal in the type of tonic level change reinforced. Some problems related to the clinical application of skin resistance level training are discussed.


Contingent vs. noncontingent EMG feedback and hand temperature in relation to anxiety and locus of control. This study was designed to measure the effects of contingent and noncontingent EMG feedback on hand temperature, anxiety, and locus of control. Two groups of six subjects each were selected on the basis of high test-anxiety scores. The groups participated in a reverse design study in which Group 1 received five sessions of contingent EMG ffedback followed by five sessions of noncontingent feedback. Group 2 received noncontingent feedback followed by contingent feedback. Results indicate a significant order of treatment effect. Subjects who received contingent feedback first produced lower EMG readings, lower test-anxiety scores, and higher hand temperatures during noncontingent feedback sessions. Receiving noncontingent feedback first may actually have interfered with utilizing contingent feedback.


Biofeedback modification of frontal EMG in normal subjects. We carried out a controlled study on the voluntary control of the frontalis muscle by biofeedback procedures employing 20 normal subjects. Subjects were randomly divided into two groups of 10: (1) the biofeedback group and (2) the control group. Each of the two groups received five training sessions of about 40 minutes' duration each on different days. The results obtained are as follows: (1) In the biofeedback group, mean EMG levels decreased progressively and markedly from 2. 16 muVp-p min the first session to 1.54 muVp-p min in the last session. On the contrary, the control group did not show constant decreases in EMG levels over sessions. (2) The changes in the heart rate did not correlate with the changes in EMG activity. (3) The changes in the respiratory rate correlated with the changes in EMG activity.


The effects of frontal EMG biofeedback and progressive relaxation upon hyperactivity and its behavioral concomitants. Hyperactive children (N = 15) and nonhyperactive children (N = 15) were compared. Hyperactive children were found to possess significantly higher (p less than .002) muscular tension levels and, in addition, presented more behavioral problems and had lower test scores. Both electromyographic (EMG) biofeedback and progressive relaxation exercises were successful in the significant reduction of muscular tension, hyperactivity, distractability, irritability, impulsivity, explosiveness, aggressivity, and emotionality in hyperactive children. The greatest improvement was seen in the area of "emotionality-aggression" (irritability, explosiveness, impulsivity, low frustration tolerance, aggresion). No differences were seen in the EMG improvement of drug and nondrug hyperactive children; both made progress under these self-control techniques. However, nondrug children made greater improvements in the behavioral area. Both EMG biofeedback and progressive relaxation resulted in improvements on the test scores of hyperactive subjects (Bender-Gestalt, Visual Sequential Memory, Digit Span, Coding). The therapy would appear to be improved by the inclusion of mental relaxation, concentration, meditation, and mind-blanking exercises for mental control.


Treatment of spastic dysphonia by EMG biofedback. Two middle-aged subjects, a male and female, with spastic dysphonia (hoarseness, stammering) were treated with both frontalis and throat muscle electromyographic (EMG) biofeedback. Both subjects reported no noticeable improvement in their voice qualities. Results of a battery of psychological tests provided some insight into the inability of EMG treatment, as well as other therapeutic approaches, to alleviate the pathology.


Baseline levels in muscle relaxation training. Variations in the baseline levels of physiological measures, a familiar problem in psychophysiological research, can affect the results of clinical applications and research in the self-control of bodily processes. In this presentation, the problem is illustrated within the context of skeletal muscle relaxation training using continuous biofeedback (BF) based on surface electromyographic (EMG) activity. In terms of the Law of Initial Values (LIV), higher EMG levels are expected to be associated with greater decreases during training. The combined results of two studies documented an LIV-like effect for pretraining baseline levels with greater EMG decreases after training for subjects with the higher pretraining baselines. Left uncorrected, such baseline differences were shown to lead to discrepant results between two identical studies, and therefore to conflicting conclusions about the effectiveness of these procedures. The available methods suggested to correct for the biasing effect of baseline differences in research are described, with particular emphasis on the analysis of covariance.


[Microelectrophoretic analysis of histones from single chromosomes and nucleoli of mosquito (Chironomis plumosus) larvae]. A simple method of microelectrophoresis for histone analysis from single fragments of polythenic chromosomes of chironomid salivary glands has been developed. The chromosomes or their fragments obtained micrurgically were dissolved in a microdroplet of 8 M urea and 1 N sulfuric acid solution. Electrophoresis was performed in 30--60 m diameter polyacrylamide gel cylinders under a layer of vaseline oil. The histones were separated into 6 electrophoretic bands which correspond to fractions H4, H2b, H2a+H3, H3-dimer, and two subfractions of histone H1. Comparison of histone electrophoregrams of the I, II, and III chromosomes showed their almost absolute identity. The ratio of fractions H4, H3, H2A, H2B as well as the ratio of histone H1 subfractions in the nucleus and in the rest of the IV chromosome cannot be visually distinguished.


[Effect of soluble matrix on the stability of modified alpha-chymotrypsin]. alpha-Chymotrypsin preparations covalently bound by Shiff bases with water soluble oxidated dextran and alginate are obtained to study the effect of charged and neutral matrices on the enzymes stability under their modification by polymers. Water soluble enzyme preparations show a catalytic activity and have a slightly enhanced thermostability. Thermostability of alpha-chymotrypsin modified by a negatively charged polymer is increased owing to the reducing of activation entropy of the denaturation reaction, while the increase of the stability of neutral polymer (dextran) modified enzyme is due to the increase of activation enthalpy of the denaturation reaction.


[Catalase biogenesis in various subcellular fractions of regenerating rat liver cells]. Dynamics of the accumulation and decay of catalase in different subcellular fractions of intact and regenerating rat liver is investigated. Biological activity of cytoplasmic factors regulating the rate of enzyme synthesis at post-transcriptional stages under partial hepatectomy is also studied. Different rates of the formation and decay of different catalase isoforms in intact and regenerating rat liver are observed.


[Properties of 2 fibrin monomer species which differ in the degree of thrombin activation. Characteristics of successively appearing active sites]. Some properties of intermediate and final products of fibrinogen activation by thrombin have been studied. The intermediate (fB) lacks peptide A, the final fibrin (fo)--A and B peptides. Peculiar pH-dependent differences have been observed when examining the effect of ionic strength on polymerization rate of fo and fB. Intermolecular links present in fo polymer are found to be stronger than those of fB polymer. Curves of clot turbidity vs pH for fo and Fb do not coincide. Considering these results together with the literature data on the fibrin-polymer H-bond system one may assume that there are much more H-bonds in fo polymer than in its fB variant. Polymerization of fB has been found to be practically unaffected by higher NaCl concentrations which activate fo polymerization. Our and literature evidence lead to the conclusion that the active site (contact region), generated by the release of the peptide A, effects polymerization through electrostatic and H-bonding, whereas on the removal of the peptide B another active site arises of which a system of H-bonds and hydrophobic interactions are characteristic.


[Poly A-protein complexes in polyribosomes of sprouting wheat embryos]. A purified polyribosome preparation has been isolated from sprouting wheat embryos. After treatment of the polyribosomes with pancreatic RNase the poly-A-sequences are found in the fractions sedimenting in the region of 8--14 S. The ability of 8--14 S poly-A-containing complexes to bind to the membrane filters at high ionic strength and their sensitivity to pronase indicate that in sprouting wheat embryo polyribosomes the poly-A-sequences occur as poly-A-protein complexes.


[Interaction of protein inhibitor from potato (protein with pI 7.3) with proteinases]. The interaction between protein inhibitor of serine proteinases from potato (protein with pI 7.3) and enzymes was investigated. The main complex present in mixtures of the inhibitor with trypsin, chymotrypsin or subtilisin contained one dimeric inhibitor molecule and one molecule of either enzyme. At high ratio enzyme/inhibitor the complexes were formed which contained more than one bound enzyme molecule. The interaction with enzymes does not include the proteolytic degradation of inhibitor with concomitant lowering of its molecular weight. The inhibitor obtained after the dissociation of inhibitor--chymotrypsin complex, preserve its capacity to form stable complexes with the enzyme.


[Plant histones. Relevance to the evolution of prokaryotes to eukaryotes]. There are many procaryotic and eucaryotic organisms in plant kingdom. It is hoped that the study of plant histones will be useful in evolutionary studies. The histones of great variety of animal species have been studied and well characterized. Less information is available concerning plant histones. The general conclusion drawn from these investigations is that most organisms of eucaryotic plant and animal species contain the same five major histone fractions. Recently the histone-like proteins were found in some primitive eucaryotes and procaryotes. Data on histones from higher and lower eucaryotes and histone-like proteins of procaryotes are reviewed. Evolution of histones and their appearance prior to that of eucaryotic cell is postulated. The role of histones in evolution of nucleosomes is discussed.


[Changes in 5-methylcytosine content of plant DNA in proportion to the amount of flowering]. A study has been made of the content of GC pairs and 5-methylcytosine in the total DNA of generative (inflorescences, flowers, flower buds) and vegetative (shoots, leaves, vegetative buds) organs in pea, tobacco and apple due to flowering gradient. In all the plants studied, the content of 5-methylcytosine in the DNA of generative organs in high as that in the DNA of vegetative organs. The DNA from various organs of one and the same plant hardly differs by the GC content. The differences in the amount of 5-methylcytosine are probably indictive of various levels of DNA methylation. Thus tissue (cell) DNA of both plants and animals differs in the content of 5-methylcytosine. Besides, methylation of genome in them changes upon flowering, i.e. we revealed the gradient of the degree of methylation of plant genome which correlates positively with the known flowering gradient. Methylation of plant genome regulated by phytohormone is possibly associated with cell differentiation and may be considered as being one of the mechanisms of regulation of transcription.


Evoked potential correlates of psychosis. Evoked potential (EP) correlates of several psychiatric disorders were investigated by applying a comprehensive EP procedure to 102 psychiatric patients and 28 nonpatients. EPs to left and right median nerve shocks, visual pattern flashes, and auditory clicks were recorded from one EOG and 14 monopolar scalp derivations. Nine age- and sex-matched groups were compared to yield the following main results: (i) EPs of overtly psychotic patients (schizophrenics, depressives, manics) differed markedly from normal, while those of patients without overt psychosis (neurotics, personality disorders, latent schizophrenics) did not; in the overtly psychotic, later EP events (100 msec or more poststimulus) were attenuated. (ii) EPs of neurotic depressives differed greatly from those of psychotic depressives. (iii) A somatosensory negative peak occurring 60-msec poststimulus (N60) was more posteriorly distributed in chronic schizophrenics (paranoid, undifferentiated) than in any other subject group. The attenuated later EP activity associated with overt psychosis was interpreted as a concomitant of cognitive (attention?) impairment, rather than of emotional disturbance.


Pattern evoked potential measurements suggesting lateralized hemispheric dysfunction in chronic schizophrenics. Visual evoked potentials (VEP) were measured to obtain evidence concerning possible lateralized hemispheric dysfunction in schizophrenia. The main results are based on the spatial distribution (12 electrodes) of a measure of VEP wave form stability over time. Subjects were 86 psychiatric inpatients and 33 nonpatients; these were grouped in three ways to permit comparisons of various age- and sex-matched diagnostic classes. Main findings were: (i) VEP wave form stability was generally lower in all types of schizophrenia than in nonpatients, nonpsychotic patients and, probably, psychotic depressives. (ii) VEP stability differed more between the hemispheres in schizophrenics and psychotic depressives than in nonpsychotic subjects; in schizophrenics, left hemisphere stability was lower than normal, whereas it was normal in psychotic depressives. (iii) VEP stability differences between the hemispheres were also greater than normal in latent schizophrenics, with less stability on the left. The results provide a direct demonstration of a left hemisphere involvement in schizophrenic dysfunction.


Behavioral analysis of chronic cocaine intoxication in the cat. Modification of cocaine's stimulant and local anesthetic behavioral effects as a function of chronic treatment was evaluated in seven female cats. Video tape of behavior pre- and post-cocaine (iv) on days 1, 4, 7, 10, and 13 in seven cats, and in addition, on days 21, 28, and 35 for s subset of four cats, was rated for several scales of the Behavioral Rating Inventory for Drug-Generated Effects (BRIDGE), developed to quantify stimulant-induced behaviors. Preseizure events were measured using scales for Tremor Intensity and Preseizure-Seizure Intensity (PSI), developed to quantify local anesthetic-induced behaviors. Behaviors associated with cocaine's local anesthetic effects, i.e., Tremor Intensity and PSI levels, showed tolerance over the treatment period, while behaviors associated with cocaine's psychomotor stimulant effects, i.e., the BRIDGE measures, showed augmentation, or reverse tolerance. These data are discussed in terms of catecholamine supersensitivity, kindling mechanisms, and stimulant models of psychosis.


The threshold number of pulses in bilateral and unilateral ECT. Using a low-energy brief-pulse stimulus, the threshold number-of-pulses required to produce a bilaterally manifested tonic-clonic seizure with unilateral and bilateral electrode placement was investigated. Unilateral placement required significantly fewer pulses; bilateral placement resulted in greater post-ictal confusion with no apparent advantage in clinical efficacy. A possible explanation in terms of intracerebral current density is proposed.


A study of relationships of serum glucose, insulin, free fatty acids, and free and total tryptophan to mental illness. To explore possible disturbances of cerebral monoamines linked to glucose metabolism, 18 schizophrenics, 21 neurotics, and 21 controls were given a 5-hr glucose tolerance test, and the effect of the glucose load on total and free tryptophan, insulin, and free fatty acids in serum was studied in medication-free patients. The data indicated intragroup differences (fasting to subsequent hours) in serum glucose, insulin, free fatty acids, and free and total tryptophan values. Intergroup differences were noted in insulin values at the first hour, in free fatty acids at fasting with neurotics exhibiting the highest values, and in free tryptophan at fasting with schizophrenics having the lowest values. Schizophrenics with perceptual disturbances (e.g., hallucinations) exhibited lower free tryptophan values when compared with other schizophrenics. The results indicated a glucose-tryptophan interaction in schizophrenics.


The acute effect of haloperidol and apomorphine on the severity of stuttering. In studies of the acute effects of haloperidol on the severity of stuttering in 12 subjects not in treatment at the time of drug evaluation, a single 0.5 mg haloperidol injection was found to increase fluency in 9 to 12 subjects, as compared with saline placebo. The average improvement in those subjects who improved was 25% on reading and 40% on spontaneous speech. Side effects from this dose of haloperidol were minimal. The effects of apomorphine on speech were not statistically significant, but increased fluency was seen in a number of subjects on the reading test. The results of this study suggest that acute drug evaluation studies may be valuable in determining the effects of various psychotropic agents on the severity of stuttering. The increased fluency after haloperidol, an agent which is felt to turn off the dopaminergic system via postsynaptic blockade, and after low-dose apomorphine, which appears to inhibit the dopamine system via presynaptic effects is consistent with a role for central dopaminergic systems in the pathogenesis of stuttering. Further studies are needed to confirm this hypothesis.


Circadian rhythm disorders in manic-depressives. Seven circular manic-depressives were studied through complete of cycles of mania and depression. In five subjects, there was evidence that a circadian rhythm free-ran fast (p less than 0.005 and p less than 0.002 in two of the subjects), and in five subjects, there was evidence that lithium slowed a circadian rhythm. The palliative benefit of lithium may derive from slowing or delaying an overfast circadian clock to prevent desynchronization. Two subjects whose circadian clocks seemed too slow were lithium nonresponders (p less than 0.05). As circadian clock frequency may be transmitted on an X-chromosome gene and may increase with age, a circadian etiology is consistent with the genetics and age distribution of manic-depressive illness. Affective disturbances could be evolutionary remnants of the photo-periodic seasonal responses in animals.


Treatment of obsessive homosexual pedophilic fantasies with medroxyprogesterone acetate. The author describes a male patient with obsessive homosexual pedophilic fantasies treated with psychotherapy and medroxyprogesterone acetate (MPA), a progestin with antiandrogen activity. Long-acting MPA was administered for a 2-month period and caused a prompt and drastic reduction in fantasies and in the anxiety and depression generated by them. MPA was observed to have psychological benefits that outlived its physiologic activity.


CSF acid monoamine metabolites in psychotic syndromes: what might they signify? Research thus far indicates that CSF 5HIAA and HVA may be correlated with state components of psychotic syndromes. HVA may be positively correlated with a component of arousal or activity. The negative correlation between 5HIAA and state variables of activity or agitation in one study suggests an inhibitory deficit in some acute psychoses or a circulating psychotomimetic substance acting on 5HT receptors. Low CSF HVA values in some psychotic patients could be a manifestation of DA receptor supersensitivity which may antedate and promote the occurrence of acute psychosis. The low CSF HVA is also consistent with a Type B monoamine oxidase deficiency in chronic patients. Such a deficiency could theoretically play a role in either (or both) state or trait behavioral components of psychotic illnesses. Decreased CSF HVA could also be related to trait behaviors in psychoses as a possible reflection of MBD. An increasingly important aspect of biological research in psychotic states in the recognition that biological studies should relate to the component behaviors which make up particular psychotic disorders.


Stability of low blood platelet monoamine oxidase activity in human alcoholics. There are now several studies in the literature which document low blood platelet monoamine oxidase (MAO) activity in alcoholics. However, these reports are in disagreement as to the stability of reduced enzyme activity over time. The present study provides evidence that reduced platelet MAO activity in alcoholics is a relatively stable phenomenon, independent of ethanol consumption and proximate factors of the illness which are associated with excessive ethanol consumption.


Clinical correlates of tricyclic antidepressant-mediated inhibition of platelet monoamine oxidase. Previous reports suggest that tricyclic antidepressants inhibit platelet monoamine oxidase (MAO) activity in vitro and in vivo. This study was undertaken to examine the relationship between tricyclic-mediated inhibition of platelet MAO and resolution of clinical signs and symptoms which are commonly associated with the depressive syndrome. The results indicate that the sedative-hypnotic effects of the tricyclics closely correlate with the magnitude of platelet MAO inhibition. It appears that these effects may be mediated through alterations in the metabolism of serotonin and/or the phenylethylamines.


EEG differences as a function of creativity, stage of the creative process, and effort to be original. Results of two experiments examining the relationship between creativity and EEG alpha wave presence are reported. In Experiment 1, it was found that more creative subjects exhibited higher alpha indices during an analogue of creative inspiration than during an analogue of creative elaboration. This pattern was not found in less creative subjects. In Experiment 2 a similar effect was found in a more controlled setting and shown to be specific to creative subjects when they are instructed to be original but not when they are given no such instructions. No consistent relationship between creativity and basal EEG alpha activity was found.


Changes in the EEG as the subject learns to recall. The EEG was monitored from posterior leads located above the left and right hemispheres, while the subject learned to recall visually presented 9-digit strings. Processing of material to be recalled led to systematic and progressive activation of the left hemisphere together with an increasing ratio in the EEG activity of the two hemispheres. As performance improved with practice, the initial activation (during the first six digits) was followed by deactivation just prior to recall. This is interpreted as reflecting a shift from active processing (rehearsal) to passive processing (echoic buffer storage). Subjects who recalled well more activated in the left hemisphere than in the right and the level of EEG activity in the left hemisphere during early trials predicted overall recall performance throughout the task. Activity in the right hemisphere was unresponsive to the presentation of material and unrelated to performance. This study shows therefore that: (i) rehearsal for short term recall is a function of left hemisphere activity, (ii) individual differences in left hemisphere activity predict performance, and finally (iii) dynamic changes in brain organisation accompany an overall improvement in performance.


Physiological differentiation of sensory and cognitive tasks as a function of warning, processing demands, and reported unpleasantness. Low and highly stressful sensory tasks (viewing slides of autopsy) were employed to assess the effects of stressful stimuli that required a minimal amount of cognitive elaboration. Cognitive (arithmetic, anagram, and digit-string memorization) tasks each at two levels of difficulty were matched for reported unpleasantness with autopsy slides to provide stimuli in which stress reactions were constant but cognitive processing requirements varied. Heart rate, skin potential level, and skin potential responses were monitored. Thirty-two subjects received two presentations of each type of task, one each of which was preceded by a warning signal. The results indicated that heart rate accelerated during cognitive tasks and decelerated during slide presentations of autopsy; the warning signal accentuated the heart-rate pattern associated with the task. Analyses of individual tasks revealed that heart rate was greater during the performance of difficult (more cognitively demanding) than easy cognitive tasks but that heart rate was not affected by the reported unpleasantness of the autopsy slides. Skin potential responses were more evident during the presentation of stressful (unpleasant) stimuli for both cognitive and sensory tasks; skin potential level, however, differentiated neither the tasks nor the stressfulness of stimuli within the tasks. These results are interpreted as being consistent with Lacey's hypothesis concerning cognitive elaboration, cardiac activity, and response patterning.


The impact of stress experience on heart rate and task performance in the presence of a novel stressor. The impact of prior stress experience on heart rate and task performance in the presence of a novel stressor was studied. During a training phase 42 female students were required to solve arithmetical problems under conditions of either no stressor, delayed auditory feedback, or distraction. Subsequently in a testing phase all subjects performed the same task in the presence of delayed auditory feedback. Training in the presence of stress resulted in decreased heart rate and better performance in the testing phase. These data were interpreted as supporting the hypothesis that training under stress-inducing conditions increases stress resistance which generalizes to a novel stressor and which leads subjects to experience the novel stressor as being less stressful.


The effects of a depressant and a stimulant drug on the contingent negative variation. Three groups, each comprising eight subjects, were twice tested with an interval of one week: one group receiving 10 and 20 mg chlordiazepoxide, another group receiving 150 and 300 mg caffeine and a control group receiving placebo and 'no-drug' treatment. During each session the CNV was determined five times: one pre-drug and four post-drug measurements, each divided in a condition with and one without 'white noise'. Based on Eysenck's theory it was predicted that the CNV would increase after administering chlordiazepoxide and would decrease after administering caffeine. Furthermore it was expected that 'white noise' would attenuate the CNV of introverts and would enhance the CNV of extraverts. The first hypothesis was significantly verified comparing the chlordiazepoxide group with the caffeine group. However, making comparisons within groups, only the decrease between the measurement before taking caffeine and the first one after administering was significant. The second hypothesis could be supported for introverts only.


The effect of warning stimulus novelty on the P300 and components of the contingent negative variation. This experiment evaluated the effects of stimulus and response probability on the P300 and components of the contingent negative variation (CNV) in three different reaction tasks. In the first task the warning stimulus (S1) indicated that the imperative stimulus (S2) would require either a left or a right button press response; in the two other tasks the S1 indicated that S2 would either require a button press response or not. The a priori probability of S1 and the response to S2 were independently varied. The results show that a novel S1 significantly increased the amplitude and latency of the P300 and early CNV component: the late CNV component, however, increased significantly when a motor response to S2 was required. Early and late CNV components also differed in midline distribution. It is concluded that the early CNV can be viewed as the slow wave part of the event-related potential to S1, while the late CNV is an event preceding shift that strongly relates to the motor requirements of S2. It is finally suggested that both the P300 and early CNV reflect an orienting response to S1.


Efficient analysis of Weibull survival data from experiments on heterogeneous patient populations. An efficient method is presented for analyses of death rated in one-way or cross-classified experiments where expected survival time for a patient at time of entry on trial is a function of observable covariates. The survival-time distribution used is a Weibull form of Cox's (1972) model. The analysis proceeds in two steps. In the first, goodness of fit of the model is checked, inefficient estimates of the parameters are obtained, and survival times adjusted for the entry covariates are calculated. In the second, efficient estimates and tests for the rate parameters are obtained. These can easily be calculated using hand or desk equipment. Reorganized data sets can be analyzed without repetition of step one, thereby reducing the computational load to hand level and facilitating exploratory data analysis.


A model for analysis of the anesthetic response. When a dose d of an anesthetic is administered intravenously, either sleep will be observed for a period of time or no sleep will occur. We developed a general approach for formulating a model for this response which reduces to a quantal response model if the duration of sleep is ignored. Several specific models illustrate the general formulation. In each case the underlying dose response relationship that corresponds to the quantal response problem is the logistic. To include the duration of sleep in the model we introduced a concept of an "active dose" which is a function of the administered dose and time. We use a set of data from a study of the response of guinea pigs to ketamine for our numerical examples.


A nonparametric test for association with censored data. A nonparametric procedure is proposed for the problem of testing association between two continuous variables when one is subject to arbitrary censoring. The motivation for the procedure derives from our finding that Cox's likelihood procedure may not adequately control the size of the test. The proposed procedure allows the censoring mechanism to depend on the independent variable, is simple computationally, and provides accurate control over the size of the test even for quite small samples. Asymptotic results suggest that it may provide a sensitive alternative to Cox's procedure. An example dealing with survival following operation for myasthenia gravis is provided, wherein a method for testing after adjustment for covariate information is described.


Estimation of the mixing proportion in a mixture of two normal distributions from simple, rapid measurements. A mixture of two or more normal distributions often provides an adequate model for the distribution of a population consisting of varying proportions of component subpopulations. We consider here the problem of estimating the mixing proportion in a mixture of two normal distributions, the parameters of which can be assumed known. Very large samples may be needed if reasonably precise estimates are to be obtained, thus bringing into consideration the cost or time involved in obtaining large numbers of exact measurements and computing the estimates from them. Simple estimators based on simple, rapidly obtained measurements may then be attractive alternatives provided efficiency losses are not too great. Three such estimators studied here are based on (a) the number of observations less than a fixed point r, (b) the nembers less than s and greater than t, and (c) the sample mean. Optimal choices of the points r, s and t are considered, and the efficiencies of the estimators relative to maximum likelihood estimators (MLE) using the full data are obtained. The simple estimators often perform sufficiently well to make the collection of full data not worthwhile in practice.


Study of urinary pyrazinamide metabolites and their action on the renal excretion of xanthine and hypoxanthine in a xanthinuric patient. A chromatographic technique on anion exchange column was developed. It permets to determine unmetabolized pyrazinamide and three major metabolities: pyrazinoic acid, 5-hydroxypyrazinoic acid and an unidentified compound. In a xanthinuric patient only traces of 5-hydroxypyrazinoic acid were found 12 hours after 3 g pyrazinamide were given. These finding confirms that pyrazinoic acid is oxidised through the the action of xanthine oxidase. Both the clearances of hypoxanthine and of xanthine are as rapid as that of endogenous creatinine in a xanthinuric patient. But the effects of pyrazinamide are different on both purine bases. Urinary excretion of hypoxanthine is slightly but not significantly reduced while excretion of xanthine is decreased by about 75%. Evidence was demonstrated that pyrazinoic acid is likely the agent causing xanthine retention. These results suggest that the mechanisms of renal transport of xanthine and hypoxanthine are different.


Experimental induction of tumor growth control by immune adjuvants: current status and some theories to be explored. Immune adjuvants have been shown to induce tumor growth control in many experimental tumor-host models. The beneficial effect depends on tumor size and type and dose of the adjuvants in question, but few experimental data elucidate, which immunological mechanisms--if any--that are directly involved in the tumor destructive processes induced by immuno-adjuvants. The importance of non-specific tumor immunity is discussed with emphasize on the importance of immuno-competent cells that react non-specifically, and that may include "self-directed" cells. Non-immunological mechanisms are proposed also to be of importance, underlining the possible role of the phenomenon of spontaneous reversion of malignant cells to a non-malignant state. It is finally stressed that both immunologic and non-immunologic properties of immunoadjuvant induced tumor growth control must be analysed before therapy with immunoadjuvants can be optimally applicated in the cancer patient.


Isozymes and differentiation.

Isozymes and differentiation. We have tried to define "isozymes" and "differentiation" because these words are often used in a too vague sense. We have noted that the physiological role of isozymes is far from being clearly understood, even for the most studied enzyme with multiple molecular forms, lactic dehydrogenase. But we have pointed out that some isozymes are specific for some adult tissues, especially liver and muscle. They constitute consequently true "markers" of differentiation. Some mechanisms of this differentiation have been made clearer by the experiments of cell hybridization. The role of isozymes in differentiation is also illustrated by the selective disappearance of isozymic markers in some pathologycal conditions, for example : cancer and muscular diseases.


Action of somatostatin, levodopa and pyridoxine on growth hormone (GH) secretion in newborn infants. We studied the effect of i.v. levodopa, pyridoxine and synthetic somatostatin in 28 normal babies during the first hours of life. Somatostatin caused a decrease in GH levels in all infants; in addition, both levodopa and pyridoxine infection paradoxically suppressed GH secretion in all subjects. It is concluded that in the first hours of life GH secretion can be suppressed by synthetic somatostatin as well as by levodopa and pyridoxine administration.


Peritoneal macrophage cytotoxicity induced by serum in vitro. The authors studied the effects of peritoneal macrophages on the growth of HP2 cells, a continuous line isolated from the transplanted Harding-Passey mouse melanoma. They found that normal peritoneal macrophages can exert a strong cytostatic effect on HP2 cells, as expressed by cell number and tritiated thymidine uptake by the target cells. The data indicates that normal heat inactivated sera from various species can render macrophages cytostatic. In addition, normal serum can amplify the cytostatic properties of macrophages from immunized animals. The results are discussed in the light of present knowledge of macrophage metabolism.


The magnesium content of the trabecular bone in diabetic subjects. Trabecular bone samples, obtained in vivo from the iliac crest, were examined for their magnesium content by atomic absorption spectrophotometry after ashing. A significant decrease was found in jevunile-type diabetics and in maturity-type patients treated with insuline as compared to non-diabetic controls. The possibility of a long-term effect of daily insulin injections is discussed.


Follow-up of sixty two cases of acute basophilic leukemia. 62 cases of ABL have been investigated over the last 20 years. In our series ABL were 5% of all acute leukaemias. Four ABL types can be distinguished : (a) the basophilic terminal phase (basophilic blastic crisis) of cronic myeloid leukemia; (b) the mixed basophilic-oesinophilic types; (c) the promyelocytic basophilic type; and (d) histio basoblastic type. The first two are quite rare. The promyelocytic basophilic type can be easily differentiated from PNL; the frequency of the latter is three times higher. Fundamental to diagnosis are cytochemical stains specific for acid mucopolysacchaes. Myelobiopsy is always essential since in almost 50% of the cases no typical cells appears in the peripheral blood. In the bone marrow Ab are very numerous and and pleiomorphic. ABL is marked from its onset by a severe symptomatology. In contrast to our experience in PNL, only do some patients with ABL achieve complete remission.


Preparation of single cell suspension from rat liver. A simple method designed for immunologic studies. Single cell suspensions from rat liver were prepared by mean of a 10 min. in vivo liver perfusion with an isotonic solution. This solution was devoid of calcium but contained 27 mM of sodium citrate and 1% of bovine serum albumin. The liver cells were dissociated over chromium nickel screen in presence of 0.8 mM of calcium and 0.25 M of saccharose; they were further separated by gravity sedimentation for 10 min. The dissociated cells, when incubated in Waymouth's medium enriched with 15% of heat-inactivated horse serum and 1% of BSA, actively synthetized urea and proteins. They also incorporated [3H] thymidine. Isolated hepatocytes, obtained without resorting to extraneous enzymes, conform to the conditions required for the study of cell surface receptors involved in immunologic recognition mechanisms.


Phagocytic properties displayed by mouse hepatocytes after virus induced damage of the sinusoidal lining. Frog virus 3 (FV 3) inoculated intravenously into mice damages sinusoidal cells and produces a decrease in the carbon uptake capacity of the liver. Histological and ultrastructural examinations have shown that in FV 3 infected animals part of the inoculated carbon is taken up by the hepatocytes and can be located inside cytoplasmic vesicles or dense bodies. The hepatocytes are also able to phagocyte latex particles of 312 nm in diameter. These observations demonstrate that once the Kupffer cells and the endothelial lining are damaged, hepatocytes can display phagocytic properties.


A fractionation of insoluble rat skin collagen. After extraction of 1% of the total collagen of rat skin by 150 mM NaCl, a 1% SDS solution extracts 80% of the total collagen, while the residue is extracted by a mixture of beta mercapto-ethanol and SDS. These extractions, which respect the peptide linkages, cleave the allysyl cross-links. They provide an insight on the composition of some insoluble collagen molecules of the skin and on the importance of disulfide bridges in their architecture.


Alleviation of experimental acute renal failure in rats by reduction of renal mass. An acute renal failure (ARF) has been produced by glycerol injection on rats unilaterally nephrectomized 48 h before. Rats with reduced renal mass showed polyuria and significantly lower azotemia than controls with ARF. This data might be explained by increased glomerular plasma flow in the remnant kidney previous to ARF induction.


Reproducibility of plasma renin activity (PRA) profile in essential hypertension patients. Whether the same patient with essential hypertension (EH) has the same PRA profile at different occasions, is still uncertain. The validity of the classification of these patients into low or normal renin hypertension depends upon the reproducibility of this profile. A nomogram based on PRA and 24 hr urine sodium in normals, was constructed by computing the regression line with its tolerance limits of not less than 95%. In 30 patients with EH, the PRA and 24 hr urine sodium were determined in 2 separate occasions. Classification of patients showed a change of 30% when PRA was taken during at least 2 hours recumbency. However, when PRA following ambulation is considered, the change appeared only in 6/30 (20%). This change was not large. Thus good reproducibility of PRA is obtained on post-ambulation PRA and changes larger than the 95% tolerance limits, are considered.


Prostaglandins released into human burn blister fluid. Acidic lipids were isolated from human burn blister fluid and the presence of prostaglandins E and F compounds was demonstrated by the thin-layer chromatography. Prostaglandins E1, E2 and F2alpha were identified and quantitatively determined by radioimmunoassay and by gas-liquid chromatography/mass spectrometry. Analyses on burn blister fluid obtained from 35 patients with skin burn indicated an extensive release of prostaglandins into the blister after burn injury in a few hours. The high levels of prostaglandins in burn blister fluid decreased gradually during 24 hours after burn.


Familial hypouricemia due to isolated renal tubular abnormality. A family with genetic hypouricemia due to isolated renal tubular abnormality in urate handling is reported. Urinary urate excretion was decreased by 61% following administration of pyrazinamide, and increased by 25% following administration of probenecid. The response to these drug suggest genotype heterogeneity of renal hypouricemia in man.


Serum, zinc, copper and insulin in diabetes mellitus. We studied serum zinc, copper, ceruloplasmin, insulin, basal glycemia and cholesterol in 49 diabetics on oral anti-diabetic agent and in 10 normal people. We found there is an elevation of serum zinc, copper and ceruloplasmin in the diabetic group that is statistically significant (p less than 0.001). There is a significant correlation between zinc and insulin (p less than 0.001), and between the quotient zinc/copper and cholesterol (p less than 0.001). The increase of plasma zinc can reflect a deficient storage or a chronic hypersecretion of insulin in hyperglucemic patients. We think that the quotient zinc/copper/might play a role in the pathogenesis of the arteriosclerosis in diabetes.


Methotrexate induced alteration of glycolysis in L1210 cells in vitro. Methotrexate, in non-lethal doses, greatly enhances anaerobic glycolysis in L1210 cells. Lactate/glucose ratio remains constant but intracellular levels of glycolytic enzymes are increased. ATP accumulating in the cells seems to reflect an alteration of regulation of the glycolysis.


Culture procedure of mesothelial cells from the rat parietal pleura. Cultures were made of mesothelial cells obtained by scraping the parietal pleura of the adult rats. The growth was restricted to close polyhedric epithelial-like cells, forming a monolayer. The cellular proliferation continued until the 7th day, followed by a stationary phases. In subcultures the mesothelial cells kept their epithelial type. The cultures were stopped on the 20th day.


The pumping mechanism of the nematode esophagus. The radial orientation of the myofilaments in the nematode esophagus raises interesting questions as to how such a structure can function as a pump. A physical model of the esophagus of Ascaris lumbricoides was developed and the membrane theory of shells applied in order to relate the observed dimensional changes to myofilament force, pressure stresses, and membrane elastic constants. By stressing the excised esophagus passively with osmotic pressure, the esophagus was shown to be elastically anisotropic with the ratio of circumferential to longitudinal elastic constants, E(psi)/E(l) approximately 2.74. When this value was incorporated, the model predicted the ratio of the respective strains, epsilon(psi)/epsilon(l), to be 0.52 during an equilibrium contraction of the esophagus. This agreed with the experimental value, 0.46 +/- 0.10, measured during occasional, prolonged muscle contractions. When measured during normal pumping, on the other hand, the value of epsilon(psi)/epsilon(l) was 0 +/- 0.10. This indicated that a nonequilibrium condition normally occurs in which a greater myofilament force per unit area of lumen membrane is not balanced by internal pressure and therefore acceleration of the lumen contents and negative intraluminal pressure occurs.The pumping action of esophagi dissected from Ascaris was observed to be normally peristaltic and periodic. Contraction was initiated by a spontaneous depolarization that propagated at 4.0 +/- 0.20 cm/s along the esophageal membrane. A wave of localized increases in the internal pressure of the muscle and localized changes in external dimensions was observed. A subsequent spontaneous repolarization, which propagated at 5.8 +/- 0.23 cm/s, triggered relaxation of the muscle during which the localized pressure and dimensional changes returned to resting values. A mechanism was deduced in which fluid is drawn into and moved along the lumen by the wave of contraction. During the wave of relaxation, the lumen contents are pressurized and injected into the intestine by elastic restoring forces.


Effects of ultraviolet irradiation and postirradiation incubation on heterogenous nuclear RNA size in murine cells. We have analyzed the decrease in synthesis of individual size classes of heterogeneous nuclear RNA (hnRNA) in ultraviolet (UV)-irradiated Merwin plasmacytoma (MPC-11) cells at various times of postirradiation incubation. HnRNA from nonirradiated control cells is distributed over a wide range from approximately 60S to 5S, with 42S RNA carrying more label than any other size class. HnRNA from UV-irradiated cells shows a dose-dependent shift in size distribution toward lower molecular weight. The size distribution of hnRNA synthesized after prolonged times of postirradiation incubation is restored toward normal, i.e., synthesis of long RNA molecules increases relative to the synthesis of short ones. Analysis of the total number of hnRNA chains synthesized during a 20-min [(3)H]uridine pulse shows a considerable reduction in their number with increasing UV dose. Murine cell lines are excision-repair-deficient but capable of post replication repair inhibited by caffeine. HnRNA transcripts of cells incubated in its presence were studied. The caffeine, which has no effect on hnRNA size in control cells, inhibits to a considerable extent the restoration of full-length transcripts during postirradiation incubation. The lack of excision repair in MPC-11 was confirmed by the analysis of pyrimidine dimers in trichloracetic acid-insoluble and soluble fractions within 8 h of postirradiation incubation.The size of parental and daughter strand DNA in UV-irradiated cells was correlated with RNA transcript size. The parental DNA in these experiments does not change its size as a consequence of UV exposure and postirradiation incubation. In contrast, daughter DNA strands are short in UV-irradiated cells and they increase in size during postirradiation incubation to reach the size of parental strands after 8 h.


A study of molecular dynamics and freezing phase transition in tissues by proton spin relaxation. Muscle, spleen, and kidney tissues from 4-wk-old C57 black mice were studied by proton magnetic resonance. Spin-lattice relaxation times at high fields and in the rotating frame, as well as the spin-spin relaxation times, are reported as a function of temperature in the liquid and frozen phase. Motions of large molecules and of water molecules and their changes at the freezing phase transition are studied. The shortcomings of the two-state fast-exchange relaxation model are discussed.


Concentration dependence of the self-diffusion of human and Lumbricus terrestris hemoglobin. The self-diffusion coefficient of the extracellular hemoglobin of Lumbricus terrestris (mol wt 3.7 x 10(6) daltons) has been measured at protein concentrations ranging from 2 to 25 g/100 ml. The self-diffusion coefficient of human hemoglobin has been measured at concentrations between 10 and 43 g/100 ml. For these measurements, (14)C-labeled hemoglobin was made to diffuse from one Millipore filter into three consecutively arranged Millipore filters containing unlabeled hemoglobin. After a suitable time the filters were separated, and the protein diffusion coefficient was determined from the distribution of radioactivity in the four filters with a table given by Kawalki (1894, Ann. Phys. Chem.52:166-190.). The following results were obtained. The diffusion coefficient of Lumbricus hemoglobin is 1.2 x 10(-7) cm(2)s(-1) at a protein concentration of 2.1 g/100 ml, and is reduced to about 1/10 of this value when the concentration is 25 g/100 ml (T = 21 degrees C). Between 0 and 16 g/100 ml the logarithm of the diffusion coefficient of Lumbricus hemoglobin falls linearly with concentration. Above 16 g/100 ml a marked increase in the concentration dependence of the diffusion coefficient is observed. Extrapolation of the data to zero hemoglobin concentration yields a limiting value of the diffusion coefficient of Lumbricus hemoglobin of 1.3 x 10(-7) cm(2)s(-1). The diffusion coefficient of human hemoglobin is 4.5 x 10(-7) cm(2)s(-1) at a hemoglobin concentration of 9.7 g/100 ml, and falls to 0.14 x 10(-7) cm(2)s(-1) at a hemoglobin concentration of 43.0 g/100 ml. In addition to diffusivities, the viscosities of human and Lumbricus hemoglobin solutions were measured in a wide range of protein concentrations.The concentration dependence of the diffusivity of Lumbricus hemoglobin is compared to that of myoglobin, ovalbumin, and tetrameric hemoglobin. Proportionality between the diffusion coefficient and the reciprocal of the viscosity of the protein solution is found for all these proteins. It is also shown that an equation proposed by Anderson (1973) gives an excellent description of the diffusivity of the various proteins up to moderate protein concentrations. Above concentrations of 16 g/100 ml for Lumbricus hemoglobin, and 30 g/100 ml for tetrameric hemoglobin, however, protein diffusivity falls much more rapidly with increasing concentration than is predicted by this equation.


Equilibrium studies of lecithin-cholesterol interactions I. Stoichiometry of lecithin-cholesterol complexes in bulk systems. The maximum molar ratio of lecithin:cholesterol in aqueous dispersions has been reported to be 2:1, 1:1, or 1:2. The source of the desparate results has been examined in this study by analyzing (a) the phase relations in anhydrous mixtures (from which most dispersions are prepared) and (b) various methods of preparing aqueous dispersions, with the purpose of avoiding the formation of metastable states that may be responsible for the variability of the lecithin-cholesterol stoichiometry. Temperature-composition phase diagrams for anhydrous mixtures of cholesterol (CHOL) with dimyristoyl (DML) and with dipalmitoyl (DPL) lecithin were obtained by differential scanning calorimetry (DSC). Complexes form with molar ratios for lecithin:CHOL of 2:1 and 1:2; they are stable up to 70 degrees C. When x(CHOL) < 0.33, two phases coexist: complex (2:1) plus pure lecithin; when 0.33 < x(CHOL) < 0.67 complexes (2:1) and (1:2) coexist as separate phases. The corresponding phase diagram in water for these mixtures was determined by DSC and isopycnic centrifugation in D(2)O-H(2)O gradients. Aqueous dispersions were prepared by various methods (vortexing, dialysis, sonication) yielding identical results except as noted below. The data presented supports the following phase relations. When x(CHOL) < 0.33, two lipid phases coexist: pure lecithin plus complex (2:1) where the properties of the lecithin phase are determined by whether the temperature is below or above T(c), the gel-liquid crystal transition temperature. Therefore, complex (2:1) will coexist with gel state below T(c) and with liquid crystal above T(c). The densities follow in the order gel > complex (2:1) > liquid crystal. The density of complex (2:1) is less sensitive to temperature in the range 5 degrees -45 degrees C compared to the temperature dependence for DML and DPL where large changes in density occur at T(c). When x(CHOL) > 0.33, CHOL phase coexists with complex (2:1); anhydrous complex (1:2) is apparently not stable in H(2)O. The results are independent of the method and temperature used for preparing the lipid dispersions. However, when dispersions are prepared by sonication or with solvents at T > T(c), an apparent 1:1 complex is formed. Evidence suggests the 1:1 complex is metastable.


Equilibrium studies of lecithin-cholesterol interactions. II. Phase relations in surface films: analysis of the "condensing" effect of cholesterol. From measurements of the equilibrium spreading pressure pie for dispersions of lecithin--dimyristoyl (DML) or dioleoyl (DOL)--and cholesterol (CHOL) in water, we have deduced the phase relations in both the aqueous dispersions and the equilibrium surface films. At 29.5 degrees C, when the mole fraction of cholesterol in the dispersion chi(CHOL) is 0 chi(CHOL) less than chi(CHOL) less than 0.33, pie is constant and equal to the value for pure lecithin (DOL or DML). The phase rule predicts than two bulk lipid phases coexist; these are pure lecithin and lecithin:cholesterol 2:1 complex. The equilibrium surface film contants only lecithin and therefore lecithin and 2:1 complex are immiscible in surface films. When 0.33 less than chi/CHOL) less than 1.0, pie is also contant with a value intermediate between that for pure lecithin and cholesterol. In  this range of lipid composition two bulk lipid phases also coexist: lecithin:cholesterol 2:1 complex and pure cholesterol. However, the equilibrium surface film contains only the 2:1 complex and, therefore, 2:1 complex is also immiscible with cholesterol in surface films. When pi less than pie, as in the case of spread films, we deduce that two surface phases may coexist; the composition of the phases will depend on chi(CHOL). When 0 less than chi(CHOL) less than 0.33, both lecithin and 2:1 complex coexist, and when 0.33 less than chi(CHOL) less than 1.0, 2:1 complex and cholesterol coexist. The "condensing" effect of cholesterol in lecithin surface films is reexamined. The effect is attributed to formation of the lecithin:cholesterol 2:1 complex and nonequilibrium conditions in the two-phase surface film.


Caffeine contracture and iodoacetate rigor in frog skeletal muscle. A comparison. Frog sartorius muscle treated with 5.0 mM or greater caffeine exhibits stiffness similar to that obtained from muscle in iodoacetate rigor. The data provide quantitative evidence that suggests that caffeine at irreversible contracture-producing concentrations somehow induces a rigor or rigorlike state in skeletal muscle.


3,4-diaminopyridine. A potent new potassium channel blocker. 3,4-diaminopyridine has been found to act very potently in selectively blocking the potassium channels of squid axon membranes. The apparent dissociation constants for this action are estimated to be 5.8 micron and 0.7 micron for external and internal applications, respectively, the potency being about 50 times higher than that of 4-aminopyridine. The block depends upon the membrane potential, time, and stimulus frequency. 3,4-diaminopyridine shows great promise as a useful tool for the study of membrane ionic channels.


Physical-chemical basis of the protection of slowly frozen human erythrocytes by glycerol. One theory of freezing damage suggests that slowly cooled cells are killed by being exposed to increasing concentrations of electrolytes as the suspending medium freezes. A corollary to this view is that protective additives such as glycerol protect cells by acting colligatively to reduce the electrolyte concentration at any subzero temperature. Recently published phase-diagram data for the ternary system glycerol-NaCl-water by M. L. Shepard et al. (Cryobiology,13:9-23, 1976), in combination with the data on human red cell survival vs. subzero temperature presented here and in the companion study of Souzu and Mazur (Biophys. J.,23:89-100), permit a precise test of this theory. Appropriate liquidus phase-diagram information for the solutions used in the red cell freezing experiments was obtained by interpolation of the liquidus data of Shepard and his co-workers. The results of phase-diagram analysis of red cell survival indicate that the correlation between the temperature that yields 50% hemolysis (LT(50)) and the electrolyte concentration attained at that temperature in various concentrations of glycerol is poor. With increasing concentrations of glycerol, the cells were killed at progressively lower concentrations of NaCl. For example, the LT(50) for cells frozen in the absence of glycerol corresponds to a NaCl concentration of 12 weight percent (2.4 molal), while for cells frozen in 1.75 M glycerol in buffered saline the LT(50) corresponds to 3.0 weight percent NaCl (1.3 molal). The data, in combination with other findings, lead to two conclusions: (a) The protection from glycerol is due to its colligative ability to reduce the concentration of sodium chloride in the external medium, but (b) the protection is less than that expected from colligative effects; apparently glycerol itself can also be a source of damage, probably because it renders the red cells susceptible to osmotic shock during thawing.


Shear deformation effects in enzyme catalysis. Metal ion effect in the shear inactivation of urease. The mechanism of the inactivation of the enzyme urease produced by subjecting its dilute solutions to hydrodynamic shear stresses in the range 0.5-2.5 Pa has been determined. By studying the kinetics of urease-catalyzed urea hydrolysis during application of hydrodynamic shear under varying chemical environments, we demonstrate that micromolar quantities of metal ions, in this case adventitious Fe, can accelerate the oxidation of thiol groups on urease and thus inactivate it when the protein is subjected to a shearing stress of order 1.0 Pa. In the absence of metal ion this stress level is ineffectual. It is proposed that this type of synergy between deformation and chemical environment may be crucial in many situations where biological macromolecules are subjected to mechanical stress.


Sickle hemoglobin gelation. Reaction order and critical nucleus size. Sickle hemoglobin (Hb S) gelation displays kinetics consistent with a rate-limiting nucleation step. The approximate size of the critical nucleus can be inferred from the order of the reaction with respect to Hb S activity, but determination of the reaction order is complicated by the fact that Hb S activity is substantially different from Hb S concentration at the high protein concentrations required for gelation. Equilibrium and kinetic experiments on Hb S gelation were designed to evaluate the relative activity coefficient of Hb S as a function of concentration. These experiments used non-Hb S proteins to mimic, and thus evaluate, the effect on activity coefficients of increasing Hb S concentration. At Hb S concentrations near 20% the change in Hb S activity coefficient generates two-thirds of the apparent dependence of nucleation rate on Hb S concentration. When this effect is explicitly accounted for, the nucleation reaction is seen to be approximately 10th-order with respect to effective number concentration of Hb S. The closeness of the reaction order to the number of strands in models of Hb S fibers suggests a nucleus close to the size of one turn of the Hb S fiber. These experiments introduce a new approach to the study of Hb S gelation, the equal activity isotherm, used here also to show that Hb S.Hb A (normal adult hemoglobin) hybrids do incorporate into growing nuclei and stable microtubules but that A.S hybridization is neutral with respect to promotion of Hb S nucleation and the sol-gel equilibrium.


Effect of ultrasound on a bilayer lipid membrane. The effects of continuous wave ultrasound at a frequency of 1 MHz in the intensity range of 0-1.4 W/cm2 on an oxidized cholesterol bilayer lipid membrane (BLM) were observed. Ultrasound at 1.5 W/cm2 broke the membrane; in the range from 0.5 to 1.4 W/cm2, it accelerated the draining of the bulk lipid solution from the annulus to the Teflon support. At all intensities it has no effect on the conductance, the capacitance, or the dependence of each on the voltage applied across the membrane. Electrical parameters were measured in the presence of aqueous solutions of NaCl, KCl, and distilled water. The motivation and results of this project are explained in relation to an overall objective of determining the specific effects of ultrasound on biological membranes.


Bend propagation in flagella. I. Derivation of equations of motion and their simulation. A set of nonlinear differential equations describing flagellar motion in an external viscous medium is derived. Because of the local nature of these equations and the use of a Crank-Nicolson-type forward time step, which is stable for large deltat, numerical solution of these equations on a digital computer is relatively fast. Stable bend initiation and propagation, without internal viscous resistance, is demonstrated for a flagellum containing a linear elastic bending resistance and an elastic shear resistance that depends on sliding. The elastic shear resistance is derived from a plausible structural model of the radial link system. The active shear force for the dynein system is specified by a history-dependent functional of curvature characterized by the parameters m0, a proportionality constant between the maximum active shear moment and curvature, and tau, a relaxation time which essentially determines the delay between curvature and active moment.


Enhancement of postreplication repair in ultraviolet-light-irradiated Chinese hamster cells by irradiation in G2 or S-phase. Postreplication repair in synchronous Chinese hamster cells was determined after split doses of ultraviolet (UV) radiation. Repair was enhanced by irradiation of cells in G2 or S-phase with a small dose of UV radiation at least 1.5 h before a three-fold larger dose of UV. There was significantly greater enhancement when the first dose was given in G2 than when it was given in the S-phase 0.5-1.5 h before the test dose. These data indicate that enhancement of postreplication repair does not require active DNA replication and qualitatively is independent of when in the cell cycle the cells are irradiated.


Models for hydrogen exchange from folded proteins. II. The kinetics of hydrogen exchange from folded proteins can be molded as a function of two continuous distributions of rate constants, kcx and kn, representing exchange from the folded and unfolded conformations, respectively. This model can account for the temperature dependence of soybean trypsin inhibitor at pH 3 and pH 6.5. The physical significance of this model, especially the shape and breadth of the kn distribution, are discussed.