Human carboxypeptidase B. II. Purification of the enzyme from pancreatic tissue and comparison with the enzymes present in pancreatic secretion. Carboxypeptidase B (peptidyl-L-lysine (-L-arginine) hydrolase, EC 3.4.12.3) has been isolated and purified to apparent homogeneity from activated extracts of human pancreas tissue. The purified enzyme has been shown to be a single polypeptide of 34 000 daltons. In this respect the enzyme from pancreatic tissue, designated native human carboxypeptidase B, differs from the two forms present in human pancreatic juice (fractions I and II), both of which are composed of two polypeptides of approximately 24 000 and 9000 daltons. In addition, the three forms of human carboxypeptidase B differ in electrophoretic mobility in polyacrylamide gel electrophoresis and in chromatographic behavior on DEAE-cellulose. Two immunological methods, micro-complement fixation and radioimmunoassay, have shown a high degree of structural similarity between the three forms of human carboxypeptidase B. Micro-complement fixation experiments indicate that the amino acid sequences of the three enzymes differ by less than one percent. In vitro digestion studies have indicated that trypsin alone is sufficient to convert native carboxypeptidase B to carboxypeptidase B II. However, no combination of trypsin,  chymotrypsin, and/or elastase was capable of converting native carboxypeptidase B to carboxypeptidase B I in vitro.


The effect of lanthanide ions on enteropeptidase-catalyzed activation of trypsinogen. Rare earths were found to be powerful inhibitors of enteropeptidase-catalyzed (enterokinase, EC 3.4.21.9) activation of trypsinogen. Inhibition was complete at a La3+ concentration of 12.5-10(-6) M in the assay system used and still detectable at a concentration of 1.25-10(-6) M. Inhibition was observed with all lanthanides tested. No significant differences between individual metals could be established under the conditions of the inhibition assay. Increasing ionic strength decreased enzyme activity and progressively diminished the inhibitory effect of rare earth ions suggesting an electrostatic basis for the mechanism of this inhibition. La3+ did not significantly affect enteropeptidase-mediated hydrolysis of N-benzoyl-L-arginine ethyl ester. Its inhibitory effect on activation of trypsinogen by enteropeptidase, therefore, must be attributed to interaction with the zymogen rather than the enzyme. Kinetic measurements show that inhibition by rare earths is noncompetitive in nature. Binding of lanthanides to the tetraaspartyl sequence near the aminoterminus of trypsinogen may prevent this group from interacting with a critical specificity subsite on the enzyme.


Inhibition of papain by isothiocyanates. During the tapping of papaya latex for papain (EC 3.4.22.2), benzyl isothiocyanate is enzymatically produced from benzylglucosinolate, a major component of the latex fluid. Benzyl isothiocyanate inhibits papain hydrolysis of alpha-N-benzoyl-L-arginine ethyl ester (Bz-Arg-OEt). Since tha availability of the papain sulfhydryl group to 5,5'-dithiobis-2-nitrobenzoid acid (Nbs2) is inversely related to the extensiveness of the isothiocyanate inhibition, and treatment by benzyl isothiocyanate reduces the affinity of activated papain to a mercurial-Sepharose column, it is proposed that the papain sulfhydryl reacts with the electrophilic functional group of this inhibitor. Fifteen isothiocyanates were selected and both the chemical reactivity antors are involved in the isothiocyanate-papain inhibition: (1) chemical reactivity of isothiocyanates, (2) presence or absence of an aromatic substitution, and (3) the spatial relationship of the aromatic moiety to the -N = C = S group of isothiocyanates. These data further suggest the presence of an 'aromatic site' near the Cys-25 sulfhydryl group of activated papain. Based on the existing model of papain molecule, the imidazole group of His-159 coincides well with our proposed aromatic site. The prospects of using isothiocyanates as chemical probes for the study of chemical environment of active sites in other enzymes are briefly discussed.


On the specificity of human renin. Studies with peptide inhibitors. The amino acid sequence around the renin substrate site is known to be identical to the N-terminal tetradecapeptide: Asp-Arg-Val-Tyr-Ile-His-Pro-Phe-His-Leu-Leu-Val-Tyr-Ser. Renin (EC 3.4.99.19) from both primates and non-primates cleaves this peptide at the leucylleucine bond. Several analogs of the octapeptide segment: His-Pro-Phe-His-Leu-Leu-Val-Tyr of this tetradecapeptide act as competitive inhibitors for human renin with inhibition constants down to 1 muM. The same peptides were shown, however, to have no or only slight affinity for non-primate renin. The substrate site has been preserved throughout evolution whereas the enzyme site for human renin is different from that of non-primate renins. The findings suggest that species-specific peptides must be developed for both studies of renin inhibition and for renin purification.


Dihydrodipicolinic acid synthase of Bacillus licheniformis. Quaternary structure, kinetics, and stability in the presence of sodium chloride and substrates. Dihydrodipicolinic acid synthase (L-aspartate-beta-semialdehyde hydro-lyase (adding pyruvate and cyclising), EC 4.2.1.52) obtained from Bacillus licheniformis was purified to homogeneity. Its molecular weight was 108 000 to 117 500, depending on the concentration of NaCl and substrates present, and it contained four subunits of identical molecular weight (28000). The Km values for pyruvate and L-aspartic semialdehyde were approximately 5.3 Km values for pyruvate and L-aspartic semialdehyde were approximately 5.3 and 2.6 mM, respectively. It was previously shown that pyruvate and a high sodium chloride concentration contributed to the stability of the enzyme. The effect of these substances and the other substrate, L-aspartic semialdehyde, on molecular weight was determined. None of these three substances significantly affected the apparent molecular weight. The effect of sodium chloride, pyruvate, and L-aspartic semialdehyde on enzyme structure was studied by determining the effect of their presence on inactivation of the enzyme by several chemical denaturants and heat. Pyruvate dramatically protected against inactivation by all of the denaturants. Sodium chloride protected against inactivation by sodium dodecyl sulfate, guanidine-HCl, urea, and heat, but somewhat facilitated inactivation by ethanol. L-Aspartic semialdehyde had no significant effect on inactivation by sodium dodecyl sulfate and ethanol; it rendered the enzyme slightly more sensitive to inactivation by guanidine-HCl and urea. The thermal melting curve obtained for the enzyme in the presence of L-aspartic semialdehyde was biphasic. The activity was reduced approximately 50% by heating for 30 min at temperatures between 50 and 80 degrees C. Only by heating at temperatures above 80 degrees C did the inactivation become complete. The partially inactivated enzyme could be reactivated by heating after removal of the L-aspartic semialdehyde. Pyruvate prevented the partial inactivation and facilitated reactivation. The only difference detected between the native enzyme and the partially inactivated form of the enzyme was that the latter had a reduced V. It is known that in other spore-formers, dihydrodipicolinate synthase increases in activity late in sporulation. This increase may be important for normal sporulation to occur. The possibility is discussed that the intracellular pool sizes of pyruvate and L-aspartic semialdehyde might have an influence on the level of dihydrodipicolinate synthase activity, by controlling the amount of partial inactivation of the enzyme that occurs in vivo.


Resolution and complementation of the labile L-leucine-pyruvate transaminase. An intermediate during enzyme formation under nitrogen starvation in Gluconobacter suboxydans. L-Leucine-pyruvate transaminase (mol. wt. 70 000) in Gluconobactersuboxydans synthesized during nitrogen starvation contained a labile form which changed to the stable one later. The labile enzyme (mol. wt. 70 000) dissocated to the two proteinaceous components: a cationic one (mol. wt. 10 000--20 000) and an anionic one (mol. wt. 50 000--60 000), during column chromatography on DEAE-cellulose. The enzyme activity was reconstructed when they were mixed. The reconstructed enzyme had almost the same molecular size and enzymatic properties as the labile and the native stable enzymes.


Microviscosity of lipid domains in human serum lipoproteins. Microviscosities for the hydrophobic lipid regions of human serum lipoproteins and for dispersions of lipids extracted from the lipoproteins have been determined using fluorescence polarization measurements with 1,6-diphenyl-1,3,5-hexatriene, a rod-like molecule, as the main fluorescent probe. Additional microviscosity measurements were carried out on LP-X, an abnormal human lipoprotein characteristic of cholestasis. Perylene, a disc-shaped fluorescent probe, was used with intact human lipoproteins in order to confirm relative microviscosity values measured with 1,6-diphenyl-1,3,5-hexatriene and to estimate the anisotropy of the lipid domains. Logarithmic plots of microviscosity against the inverse of absolute temperature, over the range of 0-40 degrees C, gave no indication of phase transitions and yielded activation energy values for all human lipoproteins and for the isolated lipids. The microviscosity results at 25 degrees C range from a high value of 6.1 +/- 0.9 P for low density lipoprotein down to 1.0 +/- 0.2P for chylomicrons, when 1,6-diphenyl-1,3,5-hexatriene is used as the probe. Activation energies vary from 9 kcal per mol to 6 kcal per mol for the intact lipoproteins. In contrast, isolated lipids have microviscosities from 2.4 +/- 0.3P for low density lipoprotein lipids to 1.0 +/- 0.2P for chylomicron lipids, with activation energies around 6 kcal per mol. The absolute microviscosity values indicate fluid yet viscous and anisotropic lipid domains in higher density lipoproteins, and more fluid and disordered states for isolated lipids and chylomicrons. Differences in microviscosities between the intact lipoproteins and isolated lipids can be attributed to the effects of proteins in restricting the mobility of lipids, these effects are strongest for low density lipoproteins, followed by high density lipoproteins, LP-X, very low density lipoproteins, and chylomicrons. Flow activation energies are throught to reflect intermolecular interactions, and are again higher for the higher density lipoproteins than for isolated lipids, or for chylomicrons.


Progesterone metabolism in vitro by testes from germ cell-free mice of different ages. Androgen biosynthesis in vitro by testes from (C57BL X WN)F1-WV/Wn (congenitally germ cell-free) and +/+ (normal) mice of different ages was investigated using [3H]progesterone as substrate. At all ages examined, the seminiferous tubules of the WV/Wn genotype were largely devoid of germ cells. However, the age dependent pattern of progesterone metabolism by germ cell-free testes were similar to that by normal testes. Conversion of progesterone to 5alpha-reduced 17-hydroxy-C21 and C19-steroids such as 3alpha,17alpha-dihydroxy-5alpha-pregnan-20-one, androsterone, 5alpha-androstane-3alpha,17beta-diol and 5alpha-androstane-3beta,17beta-diol was high in testes of 28- and 35-day-old mice of both groups. However, these 5alpha-reduced metabolities were found to be formed in very small amounts or not formed at all in testes of 20-, 120- and 150-day-old mice of both groups, in which conversion of progesterone to 17alpha-hydroxyprogesterone, androstenedione and testosterone was observed. It appears that in the absence of germinal cells, there is a normal increase and reduction of 5alpha-reductase activity in one or more classes of remaining cells during maturation of the testis.


Structure of cerebroside in Aspergillus oryzae. Structural studies on cerebroside isolated from Aspergillus oryzae were carried out using mainly gas-liquid chromatography-mass spectrometry. The major component fatty acids were 2-hydroxystearic and 2-hydroxy-trans-octadecenoic acid; branched 17?-methyl nonadecasphingadienine isomers were the predominant long-chain bases. The component sugar was only glucose. The structure of the major cerebrosides was assumed to be N-2'-hydroxystearoyl-1-O-glucosyl-17?-methyl sphingadienine and N-2'-hydroxyoctadecenoyl-1-O-glucosyl-17?-methyl sphingadienine.


Ceramide aminoethylphosphonate in the fungus Pythium prolatum. Ceramide aminoethylphosphonate was characterized from the lower fungus Pythium prolatum. The compound was purified by silicic acid column chromatography, DEAE-cellulose column chromatography, the action of phospholipase D, and two-dimensional thin-layer chromatography. Infrared spectra lacked ester bands and suggested the presence of a bonded NH group. The compound was hydrolyzed by strong acid. Sphingosine comprised 98% of the long chain bases. The predominant fatty acids were palmitate, oleate, linoleate, and an unidentified long chain acid. The aqueous portion of the hydrolysis products gave an elemental analysis consistent with 2-aminoethylphosphonate. On paper and thin layer chromatograms, the ammonium salt of the aqueous hydrolysis product chromatographed with 2-aminoethylphosphoate but not 1-aminoethylphosphonate, 2-aminoethanol, serine or alanine. This appears to be the first report of a phosphonolipid from fungi.


On the chemical structure of menaquinones with the tetrahydrogenated isoprenoid side chain. New menaquinones have been isolated from Oerskovia turbata and Brevibacterium lipolyticum in the nocardioform and coryneform groups of bacteria, which have been identified to be a series of menaquinones with a tetrahydrogenated isoprenoid chain, designated as menaquinone-9(H4) and menaquinone-8(H4), respectively, by thin layer chromatography, ultraviolet and infrared spectrophotometry and mass spectrometry. The nuclear magnetic resonance spectra of the quinones have revealed that all the two saturated dolble bonds occur in the internal units of the isoprenoid side chain.


Glycolipids of brevibacterium vitarumen. Corynomycolic acids have been identified in the lipids of Brevibacterium vitarumen. The analogy between this strain and typical aerobic Corynebacteria is borne out by these complex lipids, corynomycolic acid being linked as 6,6'-dicorynomycoloyl-trehalose (cord-factor structure) and as 6-monocorynomycoloyl-trehalose.


Ether lipid content of phosphoglycerides from the retina and brain of chicken and calf. Phospholipid contents and compositions were determined for chicken and calf retinas, chicken brain and calf gray matter. Retinal phospholipid compositions differ from brain phospholipid compositions by including a higher percentage of choline phosphoglycerides and lower percentages of ethanolamine and serine phosphoglycerides. The proportion of sphingomyelin is lower in calf retina than in calf brain. Among the ethanolamine phosphoglycerides, the proportions of the alk-1-enylacyl (plasmalogen) type are lower and the proportions of alkylacyl and diacyl types are higher in retina than in brain. The alkyacyl glycerophosphoethanolamines accounted for 7.6% and 8.9% of the ethanolamine phosphoglycerides from chicken and calf retinas respectively. Lower proportions of plasmalogens in the choline phosphoglycerides were found in retina as compared with brain. The alkylacyl glycerylphosphocholines comprised 4.0% of the retinal choline phosphoglycerides. Overall, a smaller proportion of retinal phosphilipids than of brain phospholipids contained alkyl or alk-1-enyl ether groups and the ratio of alkyl groups to alk-1-enyl groups was greater in retina than in brain.


Diol lipids. Acylated ethyleneglycol glycosides. A new type of natural glycolipid. A new type of glycolipid has been detected in ripening corn seeds. The presence of ethyleneglycol, galactose, glucose and fatty acids was shown by degradation studies. The products of alkaline deacylation were identified as galactosyl- and glycosylethyleneglycol by thin-layer chromatography and combined gas-liquid chromatography-mass spectrometry. The native ethyleneglycol galactolipid was isolated by distribution of the total lipids between heptane and 95% methanol, following silica gel column chromatography of the methanol soluble fraction. Analysis of the alkaline deacylation products of the isolated ethyleneglycol lipid as well as examination of the mass-spectrum of its tetraacetate showed the new lipid to have the structure of 1-acyl-2-(O-beta-D-galacto-pyranosyl)ethyleneglycol with palmitic, oleic and stearic acids as the main fatty acid components. The fragmentation patterns under electron impact of trimethylsilyl ethers of synthetic ethyleneglycol glycopyranosides and of 1-palmitoyl-2-(O-beta-D-tetraacetylgalactopyranosyl)ethyleneglycol are described.


The interaction of fatty acid synthetase with cytoplasmic protein in the control of the chain-length of fatty acids synthesised by the lactating rabbit mammary gland. 1. Fatty acid synthetase from rabbit mammary gland can be separated from the protein which modifies the chain-length at which fatty acids are released from the enzyme complex in the soluble fraction. This can be achieved by ultracentrifugation, precipitation with specific antibody or ammonium sulphate. 2. The chain-length modifying protein in the supernatant fraction from rabbit mammary gland was less active towards cow mammary gland fatty acid synthetase than rabbit mammary gland fatty acid synthetase in the synthesis of medium-chain fatty acids. The fatty acid synthetases from these two tissues are also immunologically non-identical. 3. It is proposed that there is a loose but specific interaction of rabbit mammary gland fatty acid synthetase with the chain-length modifying protein in regulating product chain length which is dependent on the concentration of interacting proteins. 4. The chain-lengthening effect of added malonyl-CoA decreases with increasing concentration of interacting proteins, but differences in the fatty acid chain-length with malonyl-CoA synthesised in situ by acetyl-CoA carboxylase and with added malonyl-CoA indicate that the product chain-length is sensitive to the availability of malonyl-CoA for enlongation in all but the most tightly coupled situations.


[IR-spectroscopic and radiographic study of the effect of water vapor on the structure and amorphous state-crystal transition of nucleic acid pyrimidine bases]. Effect of water vapour on sublimated films of nucleic acid pyrimidine bases was studied by IR-spectroscopy and X-ray pattern. It is found that freshly deposited films of uracil present a layered amorphous phase, of isocytosine--an amorphous phase; of cytosine--a crystal one. It is shown that water plays the role of an effective catalyzer providing at room temperature rapid transition of isocytosin from amorphous phase, uracyl from the layered amorphous phase into a crystal one. Under the effect of water sorbed molecules of cytosine changes are observed in the IR-spectrum. The latter are most significant in the region of non-plane deformation variations of NH- and NH2-groups. A mechanism of water effect on structural transformations found by us and the growth of nitrous bases crystals is suggested.


[Theoretical model of homopolymer chain adsorption on a homogenous surface]. On the basis of I. M. Lifshitz's theory the adsorption of the homopolymer on the homogenous surface is considered. It is shown that the attraction of monomers to the surface may lead not only to adsorption of the globule or coil but also to the emergence of a new peculiar phase--dislike globule without the fringe, all the monomers of which are stuck to the surface. A two-dimensional phase-diagram is plotted.


[Elastic nature of a polymeric globule]. Relative role of energetical and entropy contributions to the stresses which arise in the globule body after substrate absorption is considered. An integral solution is given for a simple model of the globule. An analysis of the result enables a conclusion that the entropy part is not small (it is large or of the same value) as compared with the energetical one, of only some peculiar globules have no evolutionary advantages.


[Physical state of crystalline proteins. III. Structure of thermal heating curves]. By microcalorimetry the processes proceeding in crystals of aspartate-transaminase and catalase during their termal heating have been studied. Decrease of temperature range within which heat is absorbed during a reduction of heating rate shows that the process of the destruction of crystal order is determined by the denaturation of protein molecules. A thin structure of heat absorption curve is found at some heating rates. It is found that during heating no perfection of defect crystallite structures takes place. The protein state in crystal is either equilibrium or quasiequilibrium.


[Fluorescent probe study of temperature-dependent conformational transitions in proteins]. Temperature-dependent conformational features of human serum (SAH) and egg albumins were studied by fluorescent probes such as 3-metoxybenzantron (MBA), dimethylaminocholkon (DMC) and 1-anilononaphtalene-8-sulfonate (ANS) in temperature range of 4--68 degrees C. It was found that these proteins undergo the conformational transitions accompanied by the changes of the quantrum yield and maximum position of fluorescence of MBA, DMA and ANS at 12--16 degrees C, 16--23 degrees C, 40--62 degrees C for SAH and at 5--25 degrees C, 46--64 degrees C for egg albumin.


[Optical rotatory dispersion and circular dichroism of enzyme- and alkali-dissolved collagen]. Viscosity, dispersion of optical rotation and circular dichroism of collagen solutions was determined. Collagen solutions were obtained after treating collagen with enzymes--protorizine or prototerrizine, or with the mixture of 2,5 M NaOH--1 M Na2SO4 and acid-soluble collagen from calf skin. Molecules of "forcedly" solved collagen have an asymmetric shape with a conformation of a three-helical helix. After being heated the latter undergoes the transformation helix-coil similar to tropocollagen molecules.


[Kinetics of the reaction of hemoglobin with carbon monoxide. I. Relaxation measurements during photolytic illumination]. The relaxation curves in HbCO solutions to steady 1 and equilibrium 2 states were investigated at different temperatures and photolytic illumination intensities I. It was observed that in case of low I they were of identical shape and had more than one relaxation time. Increase of I leads to changes in the "tails" of curves 1 and in the initial parts of curves 2; the shape of curves 2 becomes simpler. The latter is interpreted as a result of a slow relaxation of the Hb molecules conformation to an equilibrium ligand-free state just after HbCO photodissociation.


[Comparison of discrete models of charge transfer in thin membranes. II. Nonstationary conditions, small polarizing voltages]. The multi-step model of charge transfer is used to describe the transient behaviour of the membrane system. Analysis is carried out for the membranes with non-homogenous narrow pores. If the degree of non-homogenity of pores is high, slow relaxation occurs. In general the parameters of this relaxation do not coincide with those derived by one-jump approach to ion transfer through thin membrane.


[Cell molecular computer. IX. Coding principles in intracellular information processing]. Methods of coding the number and search for molecular program in a molecular computer are considered. The limited length of the nucleotide code is (see formula) where Pi -- probability of request of the given program, N -- total number of programs. Energetic expenditures for the synthesis of the code with the length l (in an ideal case without noise) E approximately 10 kT X l. Protein-nucleic recognition allows the work of the cell with almost the same expenditures on the account of Brown search in the presence of noise.


[Change in the antiradical activity of cell organoid lipids during deep freezing]. Changes of antiradical activity of cell organell lipids after freezing at --79 degrees and --196 degrees C were studied. It was shown that lipid antiradical activity diminishes after freezing. This effect was more pronounced in the organells freezed directly in tissues.


[Kinetics of retarded fluorescence of chlorophyll a in vivo in the absence of electron transport on the acceptor side of photosystem 2]. Kinetics is considered of a change of the intensity (quantum yield) of retardated chlorophyll a fluorescence, entering into the composition of the photosystem 2 in the case when the electron transport on the acceptor side of this photosystem is absent.


[Electrokinetic properties of formed elements in blood exposed to physical factors]. Constant magnetic field (300 Oe), sound oscillations (40 Db 50-20000 Hz) and electromagnetic field (3 V/cm, 50--20000 Hz) decrease the electrophoretic mobility of erythrocytes and trombocytes of dogs and human blood red cells in in vitro experiments. Bitemporal effect of alternating electric current (0,05--0,2 mA/cm2) in the same frequency region is accompanied with a similar fall of electrokinetic index of dog formic elements. The greatest effect is recorded in the range of 5000--1000 Hz both for sound oscillations and electromagnetic field. The significance of resonance effects in biological systems in the region of 1000 Hz frequency is discussed.


[Membrane potential levels in Acetabularia cells]. The membrane potential  (MP) of A. mediterranea cell is shown to have two stationary levels RP==--170 mv and EP=--80 mV and an unstable one -- level of action potential peaks -- EP=--60 mV. The following transitions between the MP levels are possible: RP leads to EP' equilibrium EP leads to RP. The transition RP leads to EP' always has an exponential region. Values of the MP levels and the time constant of RP leads to EP' transition are equal in spontaneous AP, in AP induced by switching off the light or current pulse, when the cell is treated with 10(-3) M solution of DNP and when a part of cell is amputated. It is suggested that RP leads to EP' transition takes place when the electrogenic Cl-pump is switched off, while EP leads to RP when it is switched on.


[Study of energy migration between native forms of chlorophyll at -196 degrees C by the method of sensitized fluorescence]. Mathematical decomposition of fluorescence spectra of chloroplasts and cells measured under monochromatic excitation in the regions of absorption maxima of the main native forms allowed the authors to calculate the efficiency of energy migration between forms. It is shown that 80--100% of absorbed quanta flow to the Chl 738/708 form (bean) in photosystem 1, whereas in photosystem 2, the Chl 695/690 and Chl 703/698 forms are terminal energy acceptors. Efficient backward energy transfer between the Chl 680/676 and Chl 686/682 forms and the existence of energy migration pathways passing one or two steps of the energy stairway formed by the energy levels of the chlorophyll forms are found. It is shown that chlorphyll b is not an intermediate link in the process of energy transfer from carotenoids to chlorophyll a. The intrinsic fluoresence quantum yields of the native forms are calculated.


[Electric coupling in cells without highly permeable cell contacts]. A mathematical model of two contacting cells is studied. Simple analytical formula are obtained which connect the transmission coefficient k with the parameters of contact zone (dimension of the contact region, resistence of the contact membrane, specific resistence of the interslit medium, width of intercellular slit) and with geometry of contacting cells. It is shown that in the absence of conductivity increase in the contact zone the values of transmission coefficient. k = 0.2 divided by 0.3. are available. k is evaluated for early embryonic cells. The mechanisms of electric coupling in early embryonic cells and in heart tissue are discussed.


[Dynamics of competitive sorption of metabolites from blood by carbon sorbents]. Two models of blood metabolites competitive sorption by carbon sorbents in small-size sorption column were considered: spouting bed model and a model of ideal mixing of solid and liquid phases. When the sorbilities of metabolites are very different the task of dynamics of competitive sorption comes to the system of differential equations with small parameters of different orders about derivatives. The zero degree of approximations of the system solutions was received when considering the sorption isotherm as Langmuir's isotherm. In both models a possibility of selective sorption was shown.


[Ionic nature of repeated responses of myocardial fibers]. Changing ionic composition of the environment and applying exposures which modify the conductivity of electrogenic membrane, the role of entering and leaving currents is studied in the generation of two zones of repeated responses (RR) of cat papillary muscle fibres. The first RR zone activated at a weak depolarization of the membrane (no higher than 30 mV) seems to be concerned with the functioning of the fast Na system. It was not blocked with inderal (2 divided by 5 mg/l), anor with Mn2+ ions (3mM). The second RR zone appearing at a stronger membrane depolarization (higher than 30 mv) is essentially dependent on the activity of the slow Na-Ca-system. It is activated with adrenaline (0.2 mg/l), ions of Sr2+ (5mM), Ba2+ (0.1 mM), Ca2+ (5 divided by 10 mM); blocked with Mn2+ (3 mM), Co2+ (5mM) ions, verapamile (2 divided by 4 mg/l), inderal (2 divided by 4 mg/l). The second RR zone was essentially affected with potassium ions: the 3-fold increase of Ko+ suppressed the RR of the second zone, a 3-fold decrease of Ko+ strengthened them.


[Integral characteristics of the cardiac electric generator in the repolarization period]. Integral characteristics (dipole moment, localization of the electrical centre and complexity parameter) of cardiac electrical generator for the normal dog heart during the fast repolarization period (corresponding to the T wave of electrocardiogram) are considered. The characteristics are calculated using electrical field potentials measured on a spherical surface around the heart. It is found that during the repolarization period these characteristics change with time much less and provide more accurate description of the heart electrical state than during the depolarization period (corresponding to the QRS complex of electrocardiogram). It is shown that over all the cardiac cycle the equivalent generator having form of a single dipole localized at the moving electrical centre of the heart provides average error of potential approximation that does not exceed average random error of present electrocardiographic recording technique. In addition this model includes comparatively small number of variables and has explicit physical and physiological interpretation. Thus application of such a model for describing cardiac electrical generator is more reasonable than application of the classical multipole models of high orders.


[Autooscillatory processes in the thalamocortical nonspecific system]. Dynamic properties of the thalamo-cortical system, regarded as a self-oscillating system, have been studied in experiments with chronically prepared rabbits. Different types of dynamic behaviour of the system have been revealed in response to stimulation with sine-type amplitude modulation. It is shown that self-oscillation process which develops in the thalamo-cortical non-specific system, is of relaxation type.


[Circadian rhythms of ultraweak chemiluminescence of bean roots]. Circadian rhythms of ultra-weak chemoluminescence of bean roots were investigated. It was found that under periodical change of light and darkness and without subsequent illumination a periodical change of spontaneous chemoluminescence of bean roots was observed. (The study of antiradical activity of the substances extracted from the root showed the dependence of this activity on illumination conditions.


[Tactile receptor reactions during discontinuous and sinusoidal hair oscillations]. "On"--"off" response characteristics of the afferent neurons of the sixth abdominal ganglion of the crayfish are described. They are developed in response to the stepped and sinusoidal oscillations of a receptive hair. A conclusion is made that moments of possible impulse arising in neuron response are defined by the simple input influence. Reaction variability under the action of one and the same stimulus appears due to a change of the impulse arising probability in these moments, but not because of the changes in time moments.


[Mechanism of the constant representation of the position of a sound signal source by the cricket cercal system neurons]. Previously it has been shown that some abdominal giant neurones of the cricket have constant preffered directions of sound stimulation in relation not to the cerci (the organs bearing sound receptors) but to the insect body (fig. 1) [1]. Now it is found that the independence of directional sensitivity of giant neurones on the cerci position disappears after cutting all structures connecting the cerci to the body (except cercal nerves) (fig 2). Therefore the constancy of directional sensitivity of the giant nerones is provided by proprioceptive signals about cerci position.


[Non-stationary processes in monomeric excitable media. I. Division of the arrested excitable front]. Characteristic unstationary processes in a distributed model of the excitable medium concerned with the stopping of the excitation front are considered. Conditions are determined necessary for a periodic division of the front.


[Terrain observation by the horseshoe bat Doppler echolocator]. Results of further studies of physical bases of surroundings observations with Rhinophidae echolocator are presented. The observation is carried out due to the presence of pointed down irradiation diagram petal of its probing impulse. The frequency shift and devation of the signal, reflected from elementary surroundings region, induced by Dopler effect, are calculated. It is shown that the presence in the frequency threshold curve of Rhinophidae auditory system of a narrow-tuned filter in the location frequency region and control of the frequency of eminated impulse during flight provide for a response of the auditory system to the signal reflected from each point of surroundings. The resolution thus obtained is evaluated. A technique is suggested for experimental test of the work of the system for surroundings observation.


[Work of the human visual system. IV. Reverse color discrimination and anticolor. 1st series of experiments]. It is shown that in processing of visual information visual system uses not only normally visible color differences but also the color differences of opposite sign. The term "opposite color difference" implies that the sum of any given color difference and of the opposite one is equal to zero difference.


[Calculation of the diameter distribution function of long hollow cylinders from coherent light scattering data]. A method is developed to find the particle-diameter-distribution of noninteracting long hole cylinders by means of integral transform of light- or X-ray-scattering curve. No assumptions need to be made about the form of distribution function.


[Estimation of the enthalpy of B--A transitions in DNA in water-ethanol solutions]. Enthalpy of reaction of guanidinium chloride with sodium DNA salt was determined microcalorimetrically at 25 degrees C in water-ethanol solutions of various concentrations. At low ethanol contents (up to 25 mole%) reaction is exothermic, its enthalpy being only slightly dependent on ethanol concentration. Above 28 41 mole % of ethanol reaction becomes endothermic. As above 41 mole% of ethanol in the absence of guanidinium ions A-type DNA conformation appears in the solution, which under the influence of guanidinium is converted to the B-type conformation, enthalpy of conformation transition must be included in the measured enthalpy of the reaction. Dependence of the measured enthalpy on ethanol concentration in the B--A transition region testifies to a very small value of the enthalpy change during this transition.


Purification of tRNATrp, tRNAVal, and partial purification of tRNAIle and tRNAMfet from beef liver. tRNATrp from beef lever has been purified by classical chromatographical methods. Total tRNA, prepared on a large scale (total aminoacid acceptance 1280 pmol/A260 unit) was submitted to chromatography on benzoylated-DEAE cellulose, then DEAE Sephadex. The major species accepting tryptophan issued from the second chromatography was aminoacylated with [14C] tryptophan and chromatographed on benzoylated-DEAE cellulose. The tRNA carrying the radioactive label was eluted in the ethanolic region. After stripping, the resulting tRNATrp has an acceptance of 1800 pmol/A260 unit. No isoacceptors could be demonstrated by chromatography of the pure species on RCP 5 in 6 M urea. The yield in pure tRNATrp was currently in the range of 25 to 30 percent of the total tryptophan acceptance of the starting curde tRNA.


[Characteristics of relaxation experiments for proteins with "memory"]. Conditions of a linear relaxation experiment have been analysed for the proteins with "memory", i.e., the proteins whose stationary and equilibrium kinetic parameter values are changing but slowly after external perturbation. It is shown that to measure the equilibrium kinetic characteristics of these molecules one should decrease the degree of the external perturbation till the coincidence of the shape of the relaxation curves between stationary and equilibrium states after switching on and off the perturbation.


Hemoglobin chains during foetal development in mice. Hemoglobin components present in C3H mice during foetal development were investigated. Two major embryonic hemoglobins were found, one composed of alpha and non-alpha globin chains and the other of non-alpha chains only. No foetal hemoglobin different from the adult ane embryonic hemoglobins was detected. The preparation of adult C3H alpha chain is a mixture of two alpha chains: one comprising 70 per cent of the whole amount is identical with the alpha-chain of the C57B1 strain of mice while the other 30 per cent is identical with the alpha chain of NB strain. The synthesis of these two chains is not activated at the same time during foetal development. No C57B1 alpha chain is synthesized by foetal erythrocytes on the 13th day of gestation whereas on the 18th day the synthesis of C57B1 chain is the same in the foetus and in the adult C3H mouse.


[Photosensitized luminescence of singlet oxygen in solution]. The Photoinduced afterglow of singlet oxygen was found in air saturated solutions of protoporphyrin and naphtacene in carbon tetrachloride. The excitation spectra coincide with the absorption spectra of the pigments. The lifetime is near to 7 msec, the quantum yield--to 3-10(-5). The emission maximum lies at 1270 nm. The data suggest that the luminescence is generated by oxygen in the 1 delta g state produced by the energy transfer from triplet molecules of the pigments to O2.


[Change in the elastoviscosity of supramolecular DNA of sturgeon spawn after conservation with 4.5-5% NaCl]. Elastoviscosity of supermolecular DNA of beluga, sevruga and sturgeon pawn 6 months after conservation with 4.5-5% NaCl was studied. It is shown that a positive relation exists between elastoviscosity of SM DNA and its gustatory qualities. Therefore the value of elastoviscosity of SM DNA may be used for testing the changes of sturgeon pawn properties during conservation.


Detection of a diffusible factor controlling the synthesis of a single hemoglobin chain in mice. The synthesis of hemoglobin alpha-chains was investigated in splenic colonies derived from syngenic colony-forming units injected in lethally irradiated C3H mice. Whereas normal adult mice of this strain synthesize two structurally distinct alpha-chains, the "alphaC57" and the "alpha NB", chains, it was found that erythrocytes from splenic colonies of irradiated recipient mice contained no alpha chain of the C57 type. Daily injection of serum from adult C3H mice into irradiated recipient mice of the same strain stimulates the synthesis of alphaC57 chain, whereas the injection of serum of lethally irradiated mice, drawn 8 days after irradiation, does not. It is concluded that the serum of adult C3H mice contains one or several factors that are responsible for the differential activation of the synthesis of the alphaC57 globin chain. This factor is shown to be associated exclusively with a high molecular weight fraction of serum.


[Variable fluorescence of native forms of chlorophyll at -196 degrees C]. The value (f = Ioo/Io) of variable fluorescence (delta I) of individual forms of chlorophyll a are calculated. Absence of delta I in the forms phiCl indicates that there is no energy transfer from phiC2 to phiCL.


Biosynthesis of mannan and mannolipids from GDP-Man by membrane fractions of sycamore cell cultures. Membrane fractions have been prepared from sycamore (Acer pseudoplatanus) cell suspensions grown in liquid medium. These fractions catalyzed the transfer of mannoxyl-units from GDP-(14C) Man into a polymannoside, a mannolipid and oligosaccharide-lipids. The polymannoside was partially solubilized by proteolytic digestion or maceration in sodium dodecyl sulfate-urea mixtures. However no evidence is available of a covalent linkage between the biosynthesized glycan and peptides. The structural analysis of the (14C)mannan showed that the polysaccharide was a homopolymer of beta-(1 leads to 4) linked mannose with a few branches. During the incubation of the membranes with the substrate, the polymer chains elongated with a large number of sugar units and contained 25 to 40 hexose residues per non-reducing end monomer. GDP-Glc was a competitive inhibitor of the GDP-Man: beta-mannan mannosyl-transferase, whereas GDP-Man activated a GDP-Gle: beta-glucan glucosyl-transferase present in the same membrane preparation. Two kinds of glycolipids were synthesized in the presence of GDP-(14C)Man. The first (I) contained a polar moiety characterized as a mannose-phosphate and was very similar to polyprenyl-phosphate-mannose identified in plants by Alam and Hemming. The other mannolipid (II) was hydrolyzed by mild acid into labeled oligosaccharides of high molecular weight. This material was separated into two oligosaccharide fractions, the first (II A) of MW over 5000, the second (II B) of MW around 1700. II B contained at most two labeled mannose residues per chain, linked to the non-reducing end of unlabeled units which probably contained neutral sugars and N-acetyl-osamine(s) near the reducing end. Oligosaccharide II A seemed to contain one or several II B chains.


Determination of plasma amino acids in small samples with the use of Dansyl-chloride. A radiochemical method based on dansylation of plasma samples with Dansyl-chloride and thin alyer chromatography on polyamide sheets is presented for the quantitative individual determination of plasma amino acids in very small blood samples. The results are first corrected with a norvaline internal standard and secondly with specific recovery factors for each amino acid. The results agree slosely with other methods and with already published plasma normal amino acids values in healthy adult rats.


[Study of the mechanism of action of fasciolocides using bimolecular phospholipid membranes]. The effects of compounds (see article), where M = -S-, -SO-, -SO2- and of some of their derivatives (18 substances) on electroconductivity of bimolecular lipid membranes (BLM) of different composition in 30 mM tris-HCl (pH 7.5) is studied. The results obtained are compared with literature data concerning fasciolocide and toxic effect of these substances. Certain correlations are found between the action on BLM and biological effects of substances. The analysis of the results allowed a conclusion that the latter are concerned with a discoupling effect of substances on oxidative phosphorylation in mitochondria of helmets and their host. BLM may be applied for evaluating the value of fasciolocide and toxic effects of the substances protonophores.


A computer simulation of the effect of injected anti-progesterone on progesterone levels of pregnant rats. Antibodies to progesterone injected into pregnant rats, provoke abortion if the concentration of the biologically active progesterone is reduced to a critical level. By stimulating the biological experiments in the computer we describe the time dependent changes of this progesterone fraction, as a function of the initial concentration of progesterone and of the anti-progesterone injected. Results obtained can be used to aid interpreting the findings of the biological studies and to calculate the concentration of anti-progesterone required to provoke abortion.


[Nature and fractionation of barley proteins extracted by ethanol, isopropanol and n-propanol in different proportions]. Barley alcoholsoluble protein extractabilities by aqueous ethanol, isopropanol and n-propanol were measured at room temperature. The quantities extracted by each alsohol strongly depend on the concentration of the alcohol. The most efficient concentration for the three  alcohols were by increasing order: 45 per cent ethanol, 40 per cent isopropanol, 35 per cent (w/w) n-propanol. Hrodein preparations extracted by these three alcoholic solutions and by 75 per cent (w/w) ethanol were compared by means of the flour nitrogen percentage they contain and by electrophoresis, amino-acid analysis and Sephadex G 100 gel filtration. The preparations studied do not differ markedly in their amino-acid composition or electrophoretic pattern which shows at least 17 different bands. On the other hand, Sephadex G 100 gel filtration separates two main groups of proteins, The first one is present at the same level in all preparations studied and consists of electrophoretically typical hordeins (already described hordeins). The other group represents a fraction of the preparation, the more abundant as the solvent is more effective. This second group is excluded on Sephadex G 100 chromatography and does not give well defined bands by starch gel electrophoresis. Consequently it is related to some glutelins. Nevertheless its amino-acid composition is very close to the mean hordein composition. Electrophoretic comparison with glutelins extracted by acetic acid and with hordeins, all reduced and alkylated, discloses a great similitude between this fraction, the glutelins and some hordein fast components alpha, beta and gamma.


An improved method for purification of wheat germ agglutinin (lectin) by affinity chromatography. A simple purification of wheat germ agglutinin from commercial wheat germ is described. From defatted ground wheat germ, the lectin was extracted and then purified in a single step by filtration on an ion exchange chromatography column and adsorption on an insolubilized N-acetyl glucosamine derivative. The amount of lectin obtained from 1,000 g of wheat germ was larger than 500 mg. Although the yield was at least twice higher than that obtained with other methods, no impurities could be detected, and molecular characteristics are in good agreement with the protein purified by more sophisticated procedures.


Phenolic metabolism in petunia tissues. IV. - Properties of p-coumarate : coenzyme A ligase isoenzymes. Three p-coumarate: CoA ligases were separated from Petunia leaves. There was no interconversion from one form to another. The isoenzymes had a number of common properties: optimum pH, instability in the absence of polyols, action on p-coumaric acid as the common substrate. These enzymes differed significantly with respect to: --their substrate specificity towards the other C6-C3 units of Petunia. Form Ia (caffeate: CoA ligase) acted on caffeic acid, form Ib (sinapate: CoA ligase) on sinapic acid form II (ferulate: CoA ligase) on ferulic acid. --their thermal stability. --their sensitivity to phenolics: (a) caffeate: CoA ligase was inhibited by p-coumaroyl and caffeoyl quinic esters. It was insensitive to p-coumaroyl-glucose, on one hand and to a number of flavonoids on the other. (b) ferulate: CoA ligase was specifically inhibited by naringenin. (c) sinapate: CoA ligase was not inhibited by the selected compounds. In all cases, the inhibition was of the non competitive type and the enzymes were desensized to the modifier action by thermal treatment independently from the enzyme activity. These results suggest the occurrence of distinct sites of reception for the substrate and the inhibitor on the enzyme molecule. All these data are consistent with the hypothesis of the possible participation of each individual form in a limited number of pathways. This would be of physiological interest since the metabolic fate of the different cinnamic acids could be independently controlled at the p-coumarate: CoA ligase level.


[Chicken erythrocyte nuclei: composition and analysis of phospholipids]. While many works analyse lipid composition of cellular nuclei, essentially of liver, few describe bird erythrocyte nuclei. For them very discordant results are reported due to very different methods of preparation. In the method we adopted a good reproducibility is controlled by electron microscopy, evaluation of specific enzymatic activities and by protein, RNA and DNA determinations. Total lipid content and phospholipid composition were determined showing, in agreement with other works, the predominance of phosphatidylcholine and phosphatidylethanolamine. On the contrary, the nuclear fraction is poor in sphingomyelin, which is essentially a plasma membrane phospholipid.


Control of cardiac response under aversive stimulation. Superiority of a heart-rate feedback condition. The relative heart rate effects of biofeedback training, deep muscle relaxation, and a no-feedback/music procedure were compared during two criterion situations. The first consisted of a 25-min training period during which subjects received the assigned treatments. The second consisted of the pre- to posttraining reductions in heart rate reactivity to a series of aversive tone-shock trials. On the first criterion, the heart rate decreases of the feedback and no-feedback/music groups were not clearly distinguishable; however, both groups fell significantly below the muscle-relaxation group. By contrast, on the second criterion, the three groups were clearly distinguishable, with feedback subjects evidencing the most heart rate "control", followed by the muscle-relaxation and no-feedback/music groups, respectively. On the segment of the posttraining aversive trials conducted in the absence of the feedback signal, transfer of heart rate control was incomplete for feedback subjects, but still remained below the level of the other two groups. Training effects were more pronounced on tonic than on phasic heart rate changes. The difference between the two criterion situations suggests the possible need for and feasibility of employing a situational arousal methodology in evaluating the extent and limitation of physiological training procedures.


Simultaneous biofeedback of heart rate and frontal EMG as a pretraining for the control of EEG theta activity. Following one base-line session, 20 normal subjects received four half hour sessions consisting of simultaneous feedback of heart rate and frontalis muscle (pretraining). Ten subjects received contingent (CF), the other ten noncontingent feedback (NCF). Subjects were asked to lower heart rate and frontal muscle tension (EMG). Heart rate within sessions decreased up to 19 bpm, with a mean of 4 bpm for the CF group. There was only a week decrease over sessions, however, because of the strong habituation effect. The following events accompanied the heart rate decrease: (1) an increase of the variability of the heart rate, (2) a decrease of the variance of the EMG, (3) an increased correlation between heart rate slowing and EMG decrease, and (4) an increasing subjective experience of control of heart rate and EMG. After pretraining, subjects received eight sessions of auditory feedback of their frontal EEG theta activity (four sessions with CF and four sessions with NCF in balanced order). There was a weak increase of theta for the CF condition over sessions, but a decrease within the sessions. Pretraining on heart rate and frontal EMG control had no influence on the performance during theta training. It was hypothesized that control of heart rate slowing and theta control involve different mechanisms.


Feedback control and quantification of the response of EEG alpha to visual stimulation. The response of the posterior EEG alpha thythms to visual stimulation is so variable that it is difficult to obtain reliable on-line measurement of it. Feedback between the EEG alpha and the visual stimulus (1) reduces random variation in the response and (2) facilitates on-line quantification. With feedback EEG, the response to visual stimulation is measured as a series of time durations of alpha and of no-alpha intervals in the EEG. This time series occurs in two stages: an initial disturbance followed by a recovery. The quantification of the series of time durations is achieved by fitting curves to the series of alpha time intervals and of no-alpha time intervals. These functions, computed in each trial of 30 stimulations, are an objective, quantitative definition of EEG response. The utility of the method was demonstrated by testing it with reference to well-known effects. Habituation to a repeated stimulus, dishabituation, habituation to a class of stimuli, dishabituation by changing the class of stimuli, and differences among brain-lesioned, psychiatric patients and normals were shown with a detailed quantification. It was concluded that biofeedback is the method of choice for quantitative research on the EEG component of the human orienting response.


Variations in electroencephalographic alpha activity under conditions of differential lighting and auditory feedback. The electroencephalographic alpha activity of 13 college students was monitored under conditions of darkness or dim light for six sessions, and for a seventh under the opposite condition. Auditory feedback was given for the presence of alpha activity during a 5-min orientation period and when during ten 2-min trial periods. The results indicate that: (1) alpha production in the presence of feedback did not exceed initial eyes-closed base line production; (2) introducing feedback immediately enhances alpha activity, rather than increasing production gradually; (3) under certain circumstances, dim light is sufficient to suppress alpha; and (4) after many sessions of alpha production in darkness, subjects maintain a given amount of alpha even when visual stimulation is present.


Specificity of finger pulse volume feedback during relaxation. The effect of biofeedback during brief periods of relaxation was examined. Two groups (10 subjects in each group) were asked to relax as completely as possible during a series of six 3-minute relaxation periods in each of two 1-hr sessions. One group received biofeedback based on finger pulse volume (FPV) during the relaxation trials, while the other group received no biofeedback. Measures of heart rate, respiration rate, skin conductance level, and FPV were recorded during the sessions, and subjective ratings concerning relaxation were obtained after each session. The results showed that FPV scores for the groups differed during the relaxation trials of the second session, but other measures failed to distinguish between the groups. The group that received FPV feedback revealed a significantly higher level of FPV (relative to baseline) than the group that received no feedback.


A comparison of direct blood pressure feedback and electromyographic feedback on the blood pressure of normotensives. Groups of 20 normotensive subjects were assigned to one of three conditions to help them lower their blood pressure: (1) intermittent visual feedback of blood pressure; (2) continuous analogue auditory feedback of frontal EMG; (3) an instructed, no-feedback condition. Both groups receiving feedback showed greater within-session lowering of systolic blood pressure than the no-feedback control group. Although the group receiving intermittent visual feedback of blood pressure lowered blood pressure more than the EMG feedback group at the first session, in three subsequent sessions, the two feedback groups did not differ.


[Electric conductivity of lipid membranes in the presence of proteolytic enzymes and their substrates]. It is shown that there are spasmodic changes of electroconductivity in bimolecular membranes in the presence of alpha-chimotripsin and denatured ovalbumin or glycyl-d,L-beta-phenylalanine. These conductivity changes are not due to the interaction ob proteolysis products with lipid bilayer but result from the interaction of alpha-chimo trypsin with the substrate or competing inhibitor. Probability of the state with a specific conductivity depends on the membrane voltage. A modified membrane has a low ionic selectivity.


[Study of the structural lability of biomembranes and their components by the fluorescent analysis method. IV. Kinetic characteristics of the binding of unsaturated fatty acids with bovine serum albumin]. By studying fluorescent parameters of ionic and neutral probes the kinetics of complex formation between the molecules of bovine serum albumin (BSA) and unsaturated fatty acids was investigated. The following regularities were observed: 1. Unlike the saturated fatty acids the unsaturated ones changed fluorescent parameters of the probes according to the cooperative mechanism, significantly decreasing the quantum yield values; 2. Temperature dependence of the fluorescence of both probe types in the complexes BSA -- oleic acid and BSA -- linole acid shows some bends at t=30--39 degrees C for which the lipid components is responsible.


[Lateral diffusion of rhodopsin in the surface membrane of rat retinal rod outer segment]. Isolated rat retina bleached by an intense linearly polarized light flash became dichroic with respect to the early receptor potential excited by weak polarized test flashes. Dichroism decays with the time constant ca 1 s. This means that the rod ERP is generated by the surface membrane of the outer segment. Disappearance of dichroism is due to the diffusion of rhodopsin molecules within the surface membrane. The viscosity of the membrane was found to be 6,8+/-2,1 poise, the value comparable with that determined for the rod disks in frog.


[Relation of growth and decay kinetics of the microwave photoconductivity signal of Chlorella to its culture state]. Signals of microwave photoconductivity (MPC) of Chlorella cells in various physiological states and at various illumination conditions have been studied. It was shown that cells of high photosynthetic activity and unruptured electron transfer system give MPC signals of the type I (nonmonotonic rise and decay kinetics). A decrease of photosynthetic activity leads to the appearance of MPC signals of the type II (monotonic rise and decay kinetics).


[Effect of long wave pre-illumination on the kinetic characteristics of microwave photoconductivity signals in Chlorella cells and the Emerson effect]. By the method of microwave photoconductivity the memory effects of far-red pre-illumination and Emerson effect (nonadditivity of action of radiation at two different wavelengths) for Chlorella cells were observed and studied.


[Criteria selection for the preliminary evaluation of the efficacy of antihypoxic agents]. Mathematical description is suggested of oxygen consumption by mitochondria suspension in the presence of orto-benzoquinone derivatives. An analysis of the equations obtained, in vivo conditions taken into account, has shown that the efficiency of hydrogen consumption is mainly determined by the constant value of oxidation rate of quinone reduced form, poorely depends on the substrate concentration and activity of quinone-reducing enzymes. The constant value of oxidation rate may serve as a criterion of directed synthesis of antihypoxants.


[Phenomenological approach to the behavior of cancer cells (discussion paper)]. Proceeding from theoretical notions about the adhesion of codensed phases an approach is developed which relates the physical cause of uncontrolled division of cancer cells to the excess of their surplus electrical charge over the surface energy. This concept is compared with basic experimental data. It is shown to be in coordination with the regularities of cell genesis and biophysical notions as well. Possible mechanisms of the realization of adhesive intercellular interactions are considered. Possibilities of their control are discussed, mainly the change of the values of surface energies of outer membranes due to their adsorption of "antisurfactant" samples.


[Effect of antioxidants with different antiradical activity on cornea preservation]. Changes of chemoluminescence intensity, collagen mucopolysaccaride content in the rabbit eye cornea were studied on 32 cornea of shinshilla eye conservated by dehydration under hipotenia (2 divided by 4 degrees C) for 60 days with the application of antioxidants (tocoferol, chlorhydrate 2-ethyl, 6-methyl-3-oxipyridine) having different antiradical activity. It is concluded that the application of natural antioxidant alpha-tocoferol having high antiradical activity is expedient for the conservation of cornea.


[Non-stationary processes in monomeric excitable media. III. Complex states in autoscillatory excitable media]. Stability of homogenous autooscillations in a distributed model of excitable medium is considered. The criterion of stability is found. It is shown that in the unstable state the system develops towards unhomogenous distribution of intermediates in the space. The form of the latter strongly depends on initial data.


[Nets of excitable elements. IX. Hebb nets]. It is shown that the mechanism of bond creation suggested by Hebb, acting in a neuron net without exterior effects arranges there a structure of a ring type. The activity of such a system has periodic component. Its period is close to the duration of trace processes in neuron nets. A hypothesis is suggested about a real object where this phenomenon may be observed.


[Torsional movements of the human eye. II. Slow phase of torsion]. At different experimental conditions quantitative characteristics of the slow phase of the torsional eye movements were investigated. We found the torsional drift to increase when the head tilted faster and its velocity was bigger in the dark than in the light. Asymmetry of the drift velocity was found on moving the head to and backward. It was shown that the sign of the asymmetry did not depend on rotatory movements of the cup (the suction device for eye movement registration). At the same time electric stimulation of the labyrinth changed the sign of asymmetry and without head tilting led to the torsional eye movements (nistagmus). Some subjects were able to decline the number of the torsional saccades at will, and as a result the eye made a drift up to tens of degrees long. Possible causes of imperfect vestibular and optokinetic compensation in the eye trosion were discussed.


[Thermal noise of Corti's organ hair cells]. Thermal agitation of the hair cells stereocilia of Corti organ is estimated. It is shown that with threshold sound stimulus the signal-to-noise ratio for single stereocilium and for single hair cell is less than 1. Some methods are proposed for signal-noise discrimination.


[Mechanism of generation and perception of electric fields by honey bees]. Generation and reception mechanisms of electrostatic and alternating, currents by bees are studied. It is shown that generation of electric fields is concerned with the properties of body integuments to carry a comparative large electrostatic charge. Transport of charged bodies is percieted by bees with the help of antennae subjected to the action of coulon powers. Perception of a alternating artificially generated electric fields is mainly concerned with physiological influence of induced currents flowing in the site of contact of bees to one another or to current-conducting bodies. The studies performed did not show the existence of specialized organs for the generation and perception of electric fields.


[Kinematics of crawling locomotion. I. Ideal elastic model]. One-dimensional model of polysegmental ideal-elastic body is considered, movements of which in the free state are described by wave equation. Regimes of creeping without the loss of initial energy are examined, when the moments of attachment of the segment boundaries to the substrate are synchroneous with instantaneous stopping of free oscillations. Possibility of the existence of two coordination patterns--unconcerted and concerted metachrony is shown. In the last case velocity of the metachronal wave is equal to velocity of an elastic wave, which propagates along segments in the result of attachments or deattachments of boundaries.


[Dimensionality of information structures in perceptual space (statement of the problem)]. The study deals with the problem of dimensions preservation of informational structure of objects during their reflection in different types of information storage (technical and biological).


[Aggregation of histone F2b inthe presence of salt and methanol]. The kinetics of histone F2b aggregation in the presenceof NaCl and methanole was investigated. The size of aggregates increases during 20 hours, and in the following 13 hours the size of formed complexes does not change. It was shown that the stable colloid system was formed by the olygomers of histone F2b.


[Calculation of the cooperative mechanism of information exchange in molecular biosystems]. The behaviour of diads of molecules connected with each other by weak interaction in biosystems is considered by means of density matrix. It is shown that the cooperative processes considered cannot be treated as trivial energy transfer between molcules.


[Age changes in the allosteric properties of brain acetylcholinesterase]. d-tubocurarine and procaine have been shown to inhibit the acetylcholinesterase of rat brain homogenate by coupled and non-competitive mechanism respectively, which suggests binding to enzyme peripheral sites. Judging by values of Hill coefficient negative cooperativity in interactions between procaine sites is characteristic of all ages (n=0,8 and 0,53 for young and old rats) while such cooperativity for d-tubocurarine sites appears only at old age (n=1 and 0,6 for young and old animals). Values of Ki changed in opposite directions for each of the substances with aging. Modification of the enzyme membrane microenvironment with aging was suggested as a reason for differences in enzyme allosteric behaviour.


[Effect of salts, stabilizing and destabilizing the structure of water, on the stacking association of adenosine]. A spectrophotometric study, based on the concentration relationship of electron absorption spectra, of the effects of salts which stabilize and destabilize the water structure on the constant (K) of adenosine: stacking association has been carried out. A significant decrease of K was observed in NaClO4 which embodied strong destabilizing effect. Opposite effect was observed on other salts studied. According to K value the stacking-interaction of adenosine in the range of salt concentration 0 divided by 3M for different anions and cations are arranged in rows: SO4--greater than Cl- greater than ClO4-; Na+ greater than Li+greater than K+. The data obtained suggest that the effect of salts on thermostability of various oligo- and polynucleotides and on B leads to C DNA transition may be essentially concerned with the effect of both cations and anions of salts on the stacking-interaction of bases.


[Ligand binding process and regulatory properties of proteins]. A hypothesis of the role of specific microdynamics, i.e. rapid structural oscillations (v=10(7) s-1) of the amino acid groups in the ligand binding process and in K-allosteric interactions has been suggested.


[EEG potential theory in a model with thin brain integuments. V. Tangentially oriented dipoles in the depth and on the surface of the brain]. The potentials of EEG of tangential dipoles are estimated in the model with thin integuments of the brain. These integuments slightly shunt the currents in the shell. The EEG-potentials of the sulcus wall are half-order or even more smaller than those of the gyrus EEG for the same square of syndromized sources.


[Determination of the molecular weight of human ceruloplasmin by hydrodynamic methods and x-ray small-angle scattering]. On the basis of absolute methods of estimation of molecular weight (sedimentation equilibrium method, high speed sedimentation-diffusion and small-angle X-ray scattering) the molecular weight of ceruloplasmin M=130 000+/-5000 was determined.


[Discontinous nature of heat denaturation of lysozyme]. Optical density of lysozyme solutions at 290 nm on heating from 20 to 80 degrees C is shown to be changing in multistep way. Character of the changing depends on pH and ionic strength of medium. It is assumed that the results obtained reflect the multistep nature of lysozyme thermal denaturation.


[Luminescence quenching of UV-irradiated proteins]. Kinetic curves of paramagnetic centres accumulation and quenching of the luminescence of UV-irradiated proteins at 77 degrees K are compared. Initiation of luminescence of UV-irradiated proteins at the annealing of paramagnetic centres was studied. The luminescence of UV-irradiated proteins was shown to be quenched with the paramagnetic centres formed. It was shown that protein absorption spectrum was not changed when the limiting concentration of paramagnetic centres was obtained in it.


[Analysis of the applicability of model systems to measuring the activity of lipid-soluble antioxidants by the electrochemiluminescent method]. A comparative study of two most common model systems (methanol-sodium citrate and chloroform-aceton-maleic acid (10(-3) M)) was carried out to measure lipid-soluble antioxidants by the method of electrochemiluminescence. alpha-naftole, pyrogalole, phenole, hydroquinone, acrylamide, cholesterine and alkohol lipid extract from rat liver were used as inhibitors. The analysis has shown that it is worthwhile to apply only the system chloroform-aceton-maleic acid as a model of electroluminescent studies.


Radioligand Assay.

Radioligand Assay. In radioimmunoassay and immunoradiometric assay, potency estimation involves the relation between counts of radioactivity and dose. Many workers have found the regression function to be satisfactorily represented by a logistic curve with limits that are themselves unknown parameters. This paper discusses estimation of all the parameters under the supposition (supported by empirical evidence) that the variance of a count is proportional to UJ, where U is the mean count at a dose and J is a parameter that almost certainly lies between 1.0 and 2.0. Estimation is found to be very robust, both in respect of the value taken for J and over alternative forms of least squares and maximum likelihood procedures. Special attention is given to whether the assay uses one or more doses of each test preparation, the former having important limitations but permitting some simplification of formulae. Requirements for a comprehensive computer program, suitable for routine use by assayists lacking statistical expertise and designed to produce potency estimates for a series of test  preparations in one assay, are described. Data from an assay of oestradiol are used to illustrate various points.


Symmetrical confidence intervals for bioequivalence trials. The conventional method of setting confidence intervals for the difference of the means of two normal populations gives an interval which is not, in general, symmetrical about zero. A modification of the conventional method which leads to symmetry about zero is discussed and is recommended as particularly appropriate for use in bioequivalence trials. This modification has the effect of decreasing the "effective" length of the confidence interval, on which the decision concerning bioequivalence is based, while increasing the confidence coefficient.


On the absorption probabilities and absorption times of finite homogeneous birth-death processes. This paper provides some formulas for the absorption probabilities, the mean absorption times and the variances of first absorption times in finite homogeneous absorbing birth-death processes. The results are then applied to a genetic model of Moran [1958] for computing the absorption probability densities, the mean absorption times and the variances of first absorption times. Specifically, it is shown that the probability distribution of the first absorption time is the matrix analog of exponential distribution or a mixture of exponential distributions if the transition matrix is diagonable.


On testing normality using several samples: an analysis of peanut aflatoxin data. Eight samples of size 16 and three samples of size 15 consisting of replicate determinations of aflatoxin in peanut subsamples were considered. These data were analyzed to decide whether the samples could have arisen from two-parameter normal or lognormal parents. The method of analysis consisted of first transforming the individual samples in such a way that the transformed values had uniform distributions on the unit interval under the null hypothesis. The transformed values were then pooled and tested for uniformity. Results of the analysis indicated that the normal model fitted the data quite well and definitely better than the lognormal model.


A generalization of the probit and logit methods for dose response curves. The relationship between response probability and dosage in quantal response bioassay is modelled using a four parameter class. In addition to location and scale quantities the model includes two shape parameters that essentially index skewness and heaviness of tails of the dose-response curve. The class of models includes such special cases as the logistic, normal, extreme minimum value, extreme maximum value, double exponential, exponential and reflected exponential distribution functions. Score tests are derived for logistic and normal hypotheses and certain submodels are discussed for which the model fitting is computationally convenient. The data of Bliss (1935) illustrates the potential improvement over usual methods in the estimation of critical dose levels.


Estimation for an epidemic model.

Estimation for an epidemic model. In many epidemic models the initial infection rate, suitably defined, plays a fundamental role in determining the probability of a major epidemic. An estimate for this rate is suggested on the basis of least squares and maximum likelihood methods. The model used to arrive at the estimate is a Galton-Watson process modified by letting the offspring distribution change from generation to generation in a way as to approximate to an epidemic process. The estimates of the parameter and its associated variance are easily computed and compare well with other computationally tedious methods in an application to smallpox data.


Lung cancer incidence in cigarette smokers: further analysis of Doll and Hill's data for British physicians. Doll's analysis of lung cancer incidence (mortality) in cigarette smokers is refined in more detail in this paper. His conclusion that incidence is approximately proportional to rate of smoking and the fifth power of years of smoking is shown to hold in each of several age and dose groups giving additional evidential support. The data are equally well fitted by a Weibull distribution and by a lognormal distribution with a constant geometric standard deviation. There is, however, a trend away from these fits which needs to be examined in other studies.


The estimation and interpretation of attributable risk in health research. Various measures of attributable risk are discussed together with a rationale for their use as an alternative to relative risk in health research. Methods of estimation are presented for use with three important kinds of epidemiological study design with one dichotomous risk factor for a dichotomous disease outcome; the study designs are then compared with respect to efficiency. Procedures to analyse confounded, polytomous and interacting risk factors are proposed and it shown that there is a simple relationship between two distinct estimators previously suggested for use with deleterious and beneficial (or preventive) factors. Finally the relevance of attributable risk to an assessment of the potential effects of risk factor modification is discussed in the preventive medicine framework.


Order statistics of correlated variables and implications in genetic selection programmes. Formulae are derived and examples given for the expected values of the order statistics from a sample of several groups or families of equal size where the group members have intra-class correlation t. As t increases from O the means of the highest ranking individuals are little reduced initially, but as t approaches 1 the change becomes more rapid, the total reduction depending on the number of groups. The effect on selection differentials of the intra-class correlation of family members is generally small for t less than 0.5, such as if selection is practised on individual performance. If, however, family mean performance is used in an index, the selection differentials may be substantially reduced.


The estimation of maternal genetic variances. The estimation of maternal genetic variances by a multivariate maximum likelihood method is discussed. As an illustration the method is applied to data on Tribolium using a model based on partitioning the maternal genetic effect into additive and dominance components. An alternative model due to Falconer (1965) is also fitted. The method is applied to designs suggested for estimating maternal variances by Eisen [1967]. Modifications required when parents are selected on their phenotypic values are given.


A discriminant analysis approach to the identification of human chromosomes. The identification of the various types of the 46 chromosomes in a normal human cell is formulated as a discriminant analysis problem. Derived are expressions for posterior probabilities, and rules are given for identification where the number  of chromosomes of each type is exactly known. The resulting model is applied to experimental data from chromosomes of the Denver B-group. The results using the developed model compare favorably with those of the standard discriminant analysis approach.


Thalassemia in Italy: treatment of Cooley disease and iron kinetics in heterozygotes. Because of its high prevalence in Italy, thalassemia is officially considered a disease of major social importance. Several centers have been established for the specific purpose of population screening and treatment of patients with Cooley disease. Survival, in some cases up to 20 years, has been reached by the therapeutic methods adopted, consisting mainly of an intensive transfusion program combined with splenectomy. We now face serious logistic, social, and financial problems, raised by the increasing number of patients living, estimated at around 12,000. The iron overload is not adequately controlled by the routine use of desferrioxamine. Studies of iron kinetics in heterozygotes demonstrate  specific alteration of iron metabolism (not related to the exogenous transfusion-induced overload). Therefore, treatment with iron-chelating agents might be indicated in at least some of these subjects.


Biofeedback--background and applications to physical rehabilitation. This paper presents a brief background to biofeedback applications including biofeedback techniques related to physical rehabilitation, and in particular, that of the cerebral palsied. Relevant literature is noted and there is an overview of 3 years research investigating the use of biofeedback in the management of cerebral palsied children. A theoretical framework for using biofeedback to ameliorate motor problems with the physically disabled in general is presented. The areas of investigation are head position, joint position, electromyography, spinal rotation, weight-bearing, response-feedback toys, jaw closure, and postural alignment. The results of these various programs indicate a preliminary outcome classification of feedback-sensitive, feedback trained, and feedback-learned. All children were feedback-sensitive, the majority could be trained, and several cases demonstrated a learned carry-over response. In conclusion, biofeedback training offers the advantages of therapy in natural training settings, and direct involvement of the patient.


Skeletal extension development: criteria for future designs. Experience with an intramedullary skeletal extension and a supracortical extension has been reviewed. Criteria for possible use in future developments have been outlined. Tissue interfacing with the material used in fabricating these devices were briefly discussed, stressing the importance of maintaining the skin's integrity. An artificial tendon, which attempts to bring the external mechanical ankle joint under the direct control of existing skeletal muscles, was described. Three animal models were reviewed and our reasons given for selecting the goat. Preoperative preparations, anesthesia, and the surgical procedures were described in some detail. A tabulation of the procedures done on 52 goats (Table 1) shows little difference between the intramedullary rod and the supracortical devices when only the times in place are compared. However, the supracortical devices showed no bone necrosis and produced only one case of osteomyelitis. With the intramedullary rod, five cases of necrosis and/or osteomyelitis were seen. The cone-shaped supracortical devices are somewhat vulnerable to forces in extension.


A kneeless leg prothesis for the elderly amputee, advanced version. The work described in this paper is part of a development and evaluation program, the aim of which was to bring a telescopic kneeless leg prosthesis to a reliable, commercially viable, and easily manufacturable stage. It is considered that these aims have been almost achieved, as the prosthesis appears to improve the gait characteristics significantly, compared with its first prototypes and compared with the conventional National Health Service (N.H.S.) above-knee prostheses. The clinical evaluation was carried out with three patients and its results were found satisfactory. The specific advantages of this prosthesis compared with the conventional prostheses are: improved proprioception and stability, and improvements of certain kinematic characteristics. The paper describes briefly the modified version of the prosthesis an the investigations undertaken, and also discusses the results obtained.


[The thrombocyte membrane].

[The thrombocyte membrane]. The thrombocyte membrane is characterized by several pecularities, first by its morphology which includes deep invaginations into the interior of the cell and, second, by its capacity to become stimulated by a wide variety of seemingly unrelated external agents which extend from proteases to collagen, certain immune complexes and small molecular weight substances such as ADP, adrenaline, serotonin and vasopressin. The response of the membrane to stimulation consists in a drastic rearrangement of its constituents, as exemplified by the appearance on the outer surface of components which are not accessible in the resting platelet. Stimulation may either lead to morphological changes and to aggregation or to more far-reaching alterations linked to aggregation, namely the release of substances from storage organelles and manifestations of gross contractile activity. The generation of these sequential reactions involves the production, by the exited membrane of a hitherto ill-defined signal to the interior of the cell. One of the most important consequences of this signal consists in the release, from internal sources, of calcium ions. Calcium ions are directly involved in the rapid shape change of stimulated platelets, due to their depolymerizing effect on the microtubules, they furthermore trigger the release reaction, in which the prostaglandin in system seems also to be involved and, finally, they are essential for the activation of the contractile system. Simultaneous with the release reaction, the platelet plasma membrane acquires calcium permeability; hence, in a later phase, cytoplasmic calcium originates not only from internal sources, but also from the surrounding medium. It is particularly noteworthy that all these alterations of the plasma membrane are reversible, which means that not only the essential structural rearrangements which occur upon stimulation in the membrane are reversed but also that the cell is capable of removing the Ca2+-ions which have entered the cytoplasm during the activation phase.


The thrombocyte membrane in circulatory diseases. There is no certain evidence for the proposition, often put forward, that thrombocytes, or platelets, are involved in atherogenesis. On the other hand, thrombotic deposits in arteries as well as in the blood channels of artificial organs consist at first mainly of platelets. This contribution reviews evidence indicating that the formation of such thrombi depends on alterations in the platelet membrane and that these in turn depend on an agent, apparently ADP, which is released from the erythrocytes.


[Functions of the mitochondrial membrane]. Oxidative phosphorylation in mitochondria is a membrane-bound process. Furthermore metabolic functions and transport processes are likewise integrated in the inner mitochondrial membrane. In this the mitochondrial membrane is not only the medium for these processes but can simultaneously act as modulator for their activity.


Membrane changes in malignant cells--modulation of receptors and antigens by lipids. The dynamic characteristics of lipid regions in biological membranes can be expressed in terms of microviscosity parameters. These parameters not only determine the lateral and rotational movements of specific membrane sites but also their degree of exposure to the outer surrounding. Changes in microviscosity can thus reversibly displace the vertical position of antigens or receptor sites and modulate their active expression. The lipid mediated modulation of antigens and receptors may play an active role in the various physiological manifestations of malignant cells.


[Absorption of sugars in the small intestine]. Sugars cross the brush border membranes of small intestine by various routes: two Na+-dependent carriers for both free D-glucose and D-galactose (which, in the presence of a gradient in electrochemical potential of Na+, are accumulated against their own concentration gradient); one Na+-independent non-concentrative carrier for D-fructose; various minor disaccharidase-associated systems for the transport of some of the monosaccharides arising from the disaccharides.


Sequence of events in the activation of adenylate cyclase by cholera toxin. The toxin of Vibrio Cholera causes fluid secretion from the small intestine by stimulation of adenylate cyclase and elevation of intracellular cyclic AMP concentrations. The toxin is a protein composed of subunits responsible for binding to cell membranes and a subunit responsible for the activation of adenylate cyclase. The binding subunits (B) are non-covalently bonded to the active subunit (A). The latter is composed of two polypeptides A1 and A2 linked by a disulphide bridge. Exposure of the intestine to toxin results in rapid binding to the brush border membrane. Thence follows a gradual increase in adenylate cyclase activity, and stimulation of electrolyte and fluid secretion. Enzyme localization studies show that the brush border does not contain adenylate cyclase. Thus the stimulation of adenylate cyclase by toxin which interacts with the brush border must be indirect. From recent studies it seems that an activator of adenylate cyclase can be found in cytosol from toxin-treated cells. Incubation of toxin with cytosol or dithiothreitol results similarly in the formation of an activator. Preincubation of toxin with cytosol results in more rapid activation of adenylate cyclase in liver cell membranes than direct addition of cytosol and toxin. Preincubation of cholera toxin for activation, by cytosol, is presumed to be due to the splitting of the disulphide band between the A1 and A2 components of the active subunit. The stimulatory ability resides in A1 and both A1 and NAD are required for the activation of adenylate cyclase. The toxin-stimulated adenylate cyclase has similar characteristics to the enzyme stimulated by non-hydrolysable analogs of GTP such as guanylylimidodiphosphate (GppNHp). Stimulation by either cholera or GppNHp is irreversible, the responses to catecholamines are enhanced and the enzyme can be solubilized in the activated state.


[Biologic membrane functions in health and disease. Effects of bile acids and laxatives on the mucosal transfer]. The morphologica and biochemical asymmetry of the intestinal epithelium is the precondition for the net transfer of sodium and water from the lumen to the bloodstream. Dihydroxy bile acids and diphenol laxatives belong to the group of drugs which are capable of inhibiting or reversing this net transfer in rats and humans. This property is characterized as antiabsorptive and hydragogue. In addition to their pharmacologic action, pathophysiologic (cholagenic diarrhea) and toxic symptoms (hypokalemia and secondary aldosteronism) can be ascribed to this property. Dihydroxy bile acids and diphenal laxatives render the junctions more permeable. Their mechanism of action can therefore be explained by stating that, due to increased intercellular permeability, the asymmetry of the system is lost and absorption thus comes to a standstill. Since slight hydrostatic pressure on the subepithelial side suffices to reverse the net transfer, it is assumed that in vivo the filtration pressure of the capillaries is the motive force for net transfer into the lumen.


[Pharmacologic modifications of renal tubular transport]. Possible mechanisms of transport of substances across renal tubular walls and of drug actions influencing these transports are discussed. The precise mechanisms of action of the majority of compounds which enhance or depress transtubular transports is still unknown. Certain inhibitors of transtubular transports may be competitors of the transported substances for tubular membrane carriers. Examples of changes in transtubular transports induced by drugs are reviewed. In the rat, the combined natriuretic and diuretic effects of furosemide and of compensatory adaptation, i.e. removal of the contralateral kidneys a few hours before the experiments, appear to be hyperadditive. The natriuretic and diuretic effects of acetazolamide are similarly enhanced under the conditions of compensatory adaptation. The data suggest that the natriuretic and diuretic effects of compensatory adaptation, on the one hand, and the diuretic agents, on the other hand, are due to different primary effects on the tubules. Bidirectional transports of uric acid across the walls of proximal convoluted tubules have been demonstrated in all species of animals investigated by micropuncture, microperfusion and microinjection. No net movements of uric acid occur across the wall of distal convoluted tubules. In species and under conditions of net reabsorption of uric acid by the whole kidney, the sum of the bidirectional transports across the walls of proximal convoluted tubules always results in pronounced net reabsorption. In species and races of animals characterized by overall tubular secretion of uric acid, the predominant movement in proximal convoluted tubules also tends to be net reabsorption, while the net secretion providing the amounts of uric acid, above the amounts filtered, appearing in the final urine, appears to occur in the straight parts of the proximal tubules. Possible mechanisms of action and micropuncture observations on the sites of actions of probenecid and of pyrazinolic acid, two agents which influence transtubular transports of uric acid, are discussed. The conclusion is reached that agents influencing transtubular uric acid transports probably always act on reabsorptive as well as on secretory transports and that the net result of their action on uric acid excretion may, therefore, vary in different species and under different experimental conditions. Enhancement of the urinary excretion of salicyclic acid by infusion of bicarbonate is a well-known fact. Recent micropuncture experiments indicate that this effect is probably due to either enhanced secretion or depressed reabsorption of salicylates in proximal convoluted tubules rather than on any changes of the rate of transtubular salicylate transports in lower segments of the nephron.


Influence of family factors on the incidence of lower respiratory illness during the first year of life. In a study of a cohort of over 2000 children born between 1963 and 1965, the incidence of bronchitis and pneumonia during their first year of life was found to be associated with several family factors. The most important determinant of respiratory illness in these infants was an attack of bronchitis or pneumonia in a sibling. The age of these siblings, and their number, also contributed to this incidence. Parental respiratory symptoms, including persistent cough and phlegm, and asthma or wheezing, as well as parental smoking habits, had lesser but nevertheless important effects. Parental smoking, however, stands out from all other factors as the one most amenable to change in seeking to prevent bronchitis and pneumonia in infants.


Influence of family factors on asthma and wheezing during the first five years of life. Family factors associated with the incidence of asthma and wheezing during childhood have been studied in a cohort of over 2000 children who, together with their families, were followed-up for five years. Episodes of wheezing not regarded by the parents as asthma had a different pattern of association with family factors to that found for asthma. The outcome of the two conditions in terms of ventilatory function at the age of five years was also different, in that children with a history of asthma had a lower peak expiratory flow rate than did children with a history of non-asthmatic wheezing.


Influence of personal and family factors on ventilatory function of children. We wanted to assess the relative influence of various personal and family factors upon the development of ventilatory function in young children. The relationship of several such factors to peak expiratory flow rates measured at the age of five years was studied in 454 children. These children were members of a birth cohort born between 1963 and 1965 in Harrow, north-west London, who were examined regularly from birth through the first five years of life. Beside its expected association with height, peak expiratory flow rate at the age of five years was also related to a lesser extent with peak expiratory flow rate in parents. Children with a history of lower respiratory illness had mean peak flow rates which were lower than those of children who escaped these illnesses. The earlier the onset of the illness and the more frequent its recurrence, the more marked its effect on ventilatory function. The group of children with a history of asthma and bronchitis had the lowest mean peak expiratory flow rate, but a history of bronchitis or pneumonia alone (that is, without asthma) was also associated with reduced ventilatory function. Respiratory illness beginning in the first year of life was the most potentially modifiable determinant of peak expiratory flow rate in children in this study.


Low mortality rates in industrial cohort studies due to selection for work and survival in the industry. Occupational groups are often described as being relatively healthy because their mortality rates are lower than those of the national average. Although correct this confuses the issue for those who are interested in assessing the effects of exposure to a particular chemical. In a further analysis of data collected in a study of all men ever exposed to vinyl chloride monomer in the manufacture of polyvinyl chloride in Great Britain, three factors have been shown to contribute to the low mortality rates that were observed. The three factors: the selection of a healthy population for employment, the survival in the industry of the healthier men, and the length of time that this population has been pursued, have been quantified. The mortality experience within five years of entering this industry was shown to be as low as 37% of that expected; for circulatory disease and respiratory disease it was as low as 21%. There was a progressive increase in standardized mortality ratio with the length of time since entry so that the effect had almost disappeared 15 years after entry. To avoid confounding the selection effect with the survival effect the latter was measured by separating men who survived 15 years after entering the industry according to whether or not they were still in the industry after this period. Those who had left experienced an overall standardized mortality ratio some 50% higher than those still in the industry. This effect, although consistent in the age groups between 25 and 74 years and for all cause groups studied, was greatest in those aged between 25 and 44 years and for lung cancer and respiratory disease.


Survival of healthy older people.

Survival of healthy older people. The purpose of this study was to discover any relationships which might exist between measurable variables recorded when a healthy group of men and women, aged 70 years and over, were examined and their subsequent survival time. It was found that height, body weight, systolic and diastolic blood pressures, haemoglobin, hand grip power, cardiothoracic ratio, and pulse rate are of no predictive value in the estimation of survival time. Survival is not influenced by marital status or occupational class. For both sexes the degree of kyphosis and age are useful predictive criteria in respect of survival time. However, much research work requires to be done to explain why many people die at the time they do.