Dynamics of a model for the variability of the interspike intervals in a retinal neuron. Recently, a model has been proposed to explain the statistics of the variability of interspike intervals of ganglion cells in the retina of goldfish under steady-state stimulation. In this note, it is shown that the dynamical behaviour of the model, both under steady-state and dynamical stimuli, is characterized by input-invariance of the output random process after a time transformation. This allows to study the signal-processing properties of the model, and to test its applicability by a more complete experimental analysis.


Nonlinearities of the human ERG reflected by Wiener kernels. The Electroretinograms (ERGs) of three subjects were represented by first- and second-order Wiener kernels using the analytical procedures previously reported for lower vertebrate (Marmarelis and Naka, 1973) and invertebrate (McCann, 1974) retinal studies. The variances between the kernel estimates were relatively small, yet the second-order kernels were relatively large. The significance of the nonlinearities reflected by each second-order kernel was assessed by comparing the predicted response to the white-noise stimulus obtained using a first-order kernel with that obtained using a second-order kernel.


A model for non-resolvable ambiguities.

A model for non-resolvable ambiguities. The dynamical behavior of the perception of ambiguous figures arising from the essentially nonresolvable ambiguity built in the figures themselves is analysed. Two main features of it are explored, the initial transient and the rhythmic alternation of inversions of perspective following it. The initial transient is envisaged in terms of a symmetry breaking disorder-order transformation induced by the "attention" of the observer. The rhythmic inversions of the ordered structures are classified by a model based on an ideally non linear decision equation for binary systems originally proposed to schematize the observed behavior of neurons. Finally it is suggested that the phenomena relative to the perception of ambiguous figures could represent the simplest ones among more complex situations arising in perception, in concept formation, in the sensing of emotion and in communication in general.


An inference upon the neural network finding binocular correspondence. Previously, the authors proposed a model of neural network extracting binocular parallax (Hirai and Fukushima, 1975). It is a multilayered network whose final layers consist of neural elements corresponding to "binocular depth neurons" found in monkey's visual cortex. The binocular depth neuron is selectively sensitive to a binocular stimulus with a specific amount of binocular parallax and does not respond to a monocular one. As described in the last chapter of the previous article (Hirai and Fukushima, 1975), when a binocular pair of input patterns consist of, for example, many vertical bars placed very closely to each other, the binocular depth neurons might respond not only to correct binocular pairs, but also to incorrect ones. Our present study is concentrated upon how the visual system finds correct binocular pairs or binocular correspondence. It is assumed that some neural network is cascaded after the binocular depth neurons and finds out correct binocular correspondence by eliminating the incorrect binocular pairs. In this article a model of such neural network is proposed. The performance of the model has been simulated on a digital computer. The results of the computer simulation show that this model finds binocular correspondence satisfactorily. It has been demonstrated by the computer simulation that this model also explains the mechanism of the hysteresis in the binocular depth perception reported by Fender and Julesz (1967).


[Mechanisms of non-specific prothrombin activation]. The review of different mechanisms of non-physiological non-specific prothrombin activation is given as compared with the specific activation by the factor Xa. The use of snake venom enzymes or staphylocoagulase makes possible the thrombin generation from pathological forms of prothrombin lacking of gamma-carboxyglutamic acid and incapable of complete activation into thrombin by the specific activator, factor Xa. This fact stimulated the use of non-specific activators in medicine. Investigation of non-specific prothrombin activators made possible to reveal and to trace pathways of the formation of thrombin active site. It is demonstrated that prothrombin, like other serine proenzymes (trypsinogen, chymotrypsinogen), has already formed active site. This site can be revealed under changes of the conformation of the prothrombin molecule due to the chemical modification or the complex formation with staphylocoagulase.


[Ribonucleoprotein mRNA-containing cytoplasmic particles from mouse lymphocytes before and after injection of antigen]. In mouse spleen lymphocytes mRNA was discovered not only in poliribosomes but also in lighter RNP complexes having sedimentation coefficients of 80--120S and buyoant density of 1,40--1,52 g/cm3. The incorporation of 14C-pulse aminoacid lable has shown that the most active polypeptide synthesis takes place in light RNP-complexes and not in polyribosomes. The pattern and the contents of labeled mRNA-containing particules in spleen cytoplasm changed within different periods after the antigen injection. The greatest contents of these particles have been discovered on the second day after the antign injection, 3H- and 14C-radioactivity of RNP-complexes with higher sedimentation coefficients, and that of polyribosomes was increased; the optical density of polyribosomes peak was also increased. On the 4th day after the antigen injection contents of light RNP-complexes with higher sedimentation coefficients were decreased. On the 5th day the decrease of RNP-complexes contents was more pronounced. The changes of radioactive RNP-complexes contents in spleen cytoplasm at different periods of the immune response, which can be discovered during determined period of labling, are probably due to acceleration and then to retardation of the transition of light RNP complexes into polyribosomes. It, probably, reflects the existens in spleen lymphocytes mechanisms of translation regulation, irrespective of mRNA stability which are realized during immune reaction. Periods of the translation increasing or inhibiting in immune lymphocytes don't correspond to periods of increasing or decreasing of number of antibody synthesising cells in spleen.


[Stimulation of nuclear membrane components and DNA biosynthesis in rat liver cells after inhibition of translation with cycloheximide]. After a drastic inhibition of protein synthesis (95%) in rat liver by cycloheximide (0.2-0.4 mg/100 g of body weight) the recovery and subsequently prolonged marked stimulation of proteins, lipids and DNA were found. The correlation of nuclear membrane proteins and lipids synthesis was observed in a recovery and stimulation phases. Nuclear DNA synthesis increases after the stimulation biosynthesis of nuclear membrane components (36-40 hours after cycloheximide injection). The changes of a phospholipid composition and structure organisation of nuclear membrane hydrophobic zones (by spin probe) were found in stimulated DNA synthesis (48-60 hours).


[Mobility on peptide maps of peptides obtained by tryptic hydrolysis of lysozyme oxidized at the S-S-bonds]. The peptide map obtained by tryptic hydrolysis of the lysozyme oxidized at the S--S-bonds was characterized and compared with that of tryptic hydrolysis of the reduced lysozyme. It was shown that the mobility of peptides containing oxidized amino acid residues is decreased under electrophoresis and chromatographic treatment. Under a decrease in the peptide charge during oxidation, the changes in electrophoretic and chromatographic mobilities show a correlation. In case when the peptide charge remains unchanged, only chromatographic mobility may be altered. It is demonstrated that the cystein residues significantly interfere with the effects of trypsin on the adjacent bonds.


[Destruction of mRNA poly-A sequences by polynucleotide phosphorylase in rat liver microsomes]. A possible role of polynucleotide phosphorylase (PNPase) in the destruction of poly-A fragments located at the 3'-OH end of mRNA from rat liver polyribosomes was studied. Using hybridization of mRNP particles and mRNA with poly-U Sepharose 4B, it was found that polyribosomal PNPase in vitro destroys the poly-A sequences of approximately 25% of poly-A+ mRNA during the first minutes of incubation at a high rate. The destruction of the poly-A fragment of mRNA by PNPase is incomplete, since part of it is presumably protected by proteins firmly bound to the poly-A sequences of mRNA.


[Possible biochemical mechanism of the toxic effects of barbiturates]. Administration of amytal or phenobarbital to rats results in inhibition of liver respiration determined by oxygen uptake in isolated tissue preparations. Increasing doses of phenobarbital cause an increase of inhibition of liver respiration. In vitro addition of vitamin K3 to liver preparations from rat treated by amytal or administration of vitamin K3 after barbiturate-induced intoxication reverses the inhibition of respiration. It is also shown that the lethal effects of amytal are significantly lowered after administration of vitamin K3. It is concluded that the toxic effects of barbiturates are partially due to the inhibition of mitochondrial respiration at the level of NADH-dehydrogenase.


[Modification of nucleases by soluble derivatives of polysaccharides]. Preparations of pancreatic RNAase, ribonuclease Act. rimosus and nuclease Ser. marcescens covalently bound to water-soluble derivatives of polysaccharides (m-aminobenzyl-oxymethyl ether of dextran and mannan, 4beta-oxyethylsulphonylanisol, 4beta-oxyethylsulphonylaniline, 3-Cl-2-oxypropyl ethers of dextran and dialdehydedextran) have been obtained. The yields and thermal stability of immobilized nucleases depend both upon the amount and nature of the functional groups which activate the polysaccharide. Polysaccharide aminoaryl ethers capable of binding to proteins by azocoupling present special interest in view of their utilization as modifying baskings. Regulation of effectiveness of the azocoupling reaction by means of structural changes of the diazocomponent and the reaction conditions were shown. All this allows to obtain immobilized enzymes with different physico-chemical properties.


[Structural-functional analysis of the complex between phosphorylase B and adenosine-5'-chloromethylphosphonate]. A complex of phosphorylase B with a tritium-containing AMP analogue, adenosine-5'-chloromethylphosphonate, was obtained. It is found on the basis of the results of the determination of N- and C-terminal amino acids, amino acid composition and sequence, that the peptide 1, modified by adenosine-5'-chloromethylphosphonate, corresponds to the fragment 185-191 in the primary structure of phosphorylase B, and is probably located in the allosteric center of the enzyme. The peptide 2, which is bound with the AMP analogue and corresponds to the fragment 795-798, is suggested to be located at the site of binding the second AMP molecule. The arginine residue 184 is discussed as a possible functional amino acid protein interacting with 5'-phosphate AMP group.


[Phospholipid composition of lymphocytes from normal and leukemic blood, lymph, lymph nodes and spleen of cattle]. The phospholipid composition and cholesterol content of lymphocytes from bovine blood, lymph, lymph-nodes and spleen were studied. The cholesterol/phospholipid molar ratio in the normal lymphocytes of blood and spleen was found to be about two times higher than that in the normal lymphocytes from lymph and lymph-nodes. On lymphocytic leukemia the cholesterol/phospholipid molar ratio of the blood lymphocytes decreased sharply, whereas that in lymph and lymph-nodes lymphocytes was unaffected.


[Kinetics and thermodynamics of heat inactivation of L-threonine-L-serine dehydratase from human liver]. It has been shown that heat inactivation of L-threonine- and L-serine dehydratase activities at 37; 45; 50 and 55 degrees C in human liver extracts (the liver was ectracted with buffer containing 1.10(-5) M of pyridoxal 5'-phosphate) in course of time is practically identical, and characterizes by the same of values of activation energy of heat inactivation process, activation enthalpy of this process, activation free energy of that and activation enthalpy of the heat inactivation process. A rise of pyridoxal 5'-phosphate concentration (to 2.10(-4) M) in the buffer used for the liver extraction and hence in the medium in which the heat inactivation process was carried out stabilises L-threonine- and L-serine dehydratase activities against the inactivation at 55 degrees C. It has been concluded thatL-threonine- and L-serine dehydratase activities in human liver belong to the single protein or to two proteins having very like physico-chemical properties, and that pyridoxal 5'-phosphate is essential for this enzyme not only as coenzyme but also it is necessary to support active and stable conformation of this oligomeric protein.


[Changes in the protein composition of nuclear membranes of canine kidneys induced by amphotericin B in vivo]. Intraveneous injection of amphotericin B significantly affects the protein composition of canine kidney nuclear membranes. Electrophoresis in polyacrylamide gel showed that injection of this antibiotic results in a considerable loss or complete disappearance of the histone fractions H1 and H4 (depending on the dose) and a decrease in the content of fraction H3 in the membrane proteins. The fractionation spectrum of other nuclear membrane proteins also shows deviations from normal. One of possible reasons for that is the increased enzymatic degradation of the proteins. It is also probable that the changes in the protein composition of nuclear membranes are due to the presence of sodium deoxycholate in the antibiotic drug and may be accounted for by the nephrotoxic effect of polyenoic antibiotics.


[Chromatin RNA as a factor decreasing chromatin fragmentability under endonucleolysis]. Rat liver chromatin fragments obtained after the chromatin digestion with Ca,Mg-dependent intranuclear endonuclease were studied using electrophoresis in polyacrylamide gel concentration gradient. It is found that the content of large chromatin fragments decreases in the presence of exogenous RNAse. Possible structural role of RNA in the chramatin organization is discussed.


[Peptidase activity of Coccidioides immitis]. Glycyl-L-leucinehydrolase consisting of three molecular units was extracted from C. immitis solid cultural medium. During fractionation in polyacrylamide gel of the enzyme-containing extract a 50-fold purification of the enzyme isoform with molecular weight 12,800 is achieved. The enzyme is heat-stable, active in the narrow pH range and hydrolizes peptide bonds containing glycine. Its activity is not inhibited by none of the protease inhibitors tested.


[Regulation of the activity of GTP-cyclohydrolase, the enzyme of the first step of flavinogenesis in yeasts]. The kinetic properties and regulation of activity of GTP-cyclohydrolase, the enzyme of the first step of flavinogenesis in the Pichia guilliermondii yests, partially purified by gel-filtration were studied. It was found that the curve of the dependence of reaction rate on substrate concentration is non-hyperbolic. FAD inhibited the enzyme activity, while riboflavin and FMN had no such effect. In addition to FAD, 5'-AMP, 3',5'-AMP, ADP, ATP, NAD and NADP inhibited the enzyme activity. Under combined action of FAD and AMP on GTP-cyclohydrolase no synergetic or antagonistic effects of the inhibitors on the enzyme activity were observed. The enzyme appreciably lost its sensitivity to FAD and AMP after thermal treatment. The data obtained suggest that GTP-cyclohydrolase from P. guilliermondii is an allosteric enzyme, which is inhibited by the end product of flavinogenesis FAD, as well as by other 5'-AMP-containing nucleotides.


[Changes in the specificity of DNA methylation in cattle blood lymphocytes under chronic lymphoid leukemia]. Under conditions of chronic (spontaneous) lympholeucosis the amount of 5-methylcytosine in cattle blood lymphocyte DNA is decreased approximately by 30%. No other changes in the DNA (e. g. GC-content, Tm, amount of pyrimidine sequences differing in their lengths and composition) were observed. Thus, the decrease in the amount of 5-methylcytosine in lymphocyte DNA is due to a decrease in DNA methylation. This decrease is non-random and involves mainly the Pu-m5C-Pu sequences without affecting the long pyrimidine blocks. In nuclear extracts from lymphocytes of healthy animals the DNA-methylase activity having an optimum at pH 6,0 was found; the DNA-methylase activities found in the nuclear extracts of leukaemic cow lymphocytes had their optima at pH 5,5 and 7,5. In vitro the DNA-methylase activities of leukaemic lymphocytes nuclei methylate the cytosine residues of DNA in other sequences than enzyme(s) of the extracts from normal lymphocyte nuclei. Changes in the pattern of DNA-methylase activities as well as the decrease and distortions in the character of DNA methylation may underlie the disturbances in the regulation of transcription of genome and cause the transformation of cells under conditions of lympholeucosis.


[Interaction between polynucleotides and mitochondria from rat liver]. The interaction between labelled polynucleotides and the mitochondrial membrane was studied. It was shown that DNA and mRNA form a complex with the mitochondria and mitoplasts (i. e. mitochondria devoid of the outer membrane); this process does not depend on the energy state of mitochondria. Within the complex polynucleotides are accessible to the effects of nucleases. The complex formation strongly depends on the concentration of Mg2+ and is inhibited by Na+. It was found that polynucleotides are effectively bound to protein-free artificial membranes isolated from the total mitochondrial lipids. The data obtained suggest that in the presence of Mg2+ polynucleotides form a complex with the lipid components of the mitochondrial membrane.


[Isolation of bacterial luminescence reaction inhibitor from Photobacterium sp. cells]. The factor having a strong inhibitory effect on bacterial luminescence was isolated from the luminous bacteria species Photobacterium sp. The inhibitor purified by gel filtration on the biogel and by DEAE chromatography was homogenous (single bound during electrophoresis in polyacrylamide gel), it reacted with coomassie brilliant blue and gave a positive Lowry reaction on protein. Molecular weight was about 30,000 as determined by SDS-polyacrylamide gel electrophoresis. The absorption spectrum was characterised by the maximum at 209 nm and unexpressed maximum in the region of 260 nm. It was shown that the inhibitor had an efficient inhibitory effect on both partially- and highly purified luciferase preparations from different species of luminous bacteria, but it produced no effect on the activity of specific NADH: FMN-oxidoreductase.


[Oxidation of some substrates in the presence of NAD(P)-dependent oxidoreductases and 4-anilino-5-methoxybenzoquinone-1,2 with transfer of reducing equivalents to oxygen]. A reaction sequence for oxidation of L-lactate, ethanol, D-glucose-6-phosphate, and isocytrate by oxygen in the presence of NAD(P)-dependent oxidoreductases and 4-anilino-5-methoxybenzoquinone-1,2 was studied. A complete reaction sequence includes (1) oxidoreduction of a corresponding substrate with a specific NAD(P)-dependent dehydrogenase and formation of NAD(P)H (2) reduction of AMOBQ, AMOBQHa formation in the oxidoreduction of NAD(P)H and AMOBQ, catalized by menadione reructase (EC 1.6.99.2); (3) oxygen reduction with AMOBQH2 in a spontaneous or enzymic reaction. AMOBQ plays a catalytic role in the transfer of reducing equivalents to oxygen in the above--menshioned systems. Possible biochemical mechanism for aminoaromatic ortho-benzoquinone derivatives is discussed.


[Effect of Ca2+ ions on phospholipase D interaction with mitochondrial membrane phospholipids]. Effect of phospholipase D and Ca2+ ions on mitochondrial polyenzyme systems is studied. Phospholipase D is found to have a lytic effect on mitochondrial membrane phospholipids both in the presence and in the absence of Ca2+ ions. Low Ca2+ concentrations stimulate the phospholipase D-membrane interaction, thus increasing the efficiency of the enzyme action. The degradation of mitochondrial membrane phospholipids or their heating result in a decrease of membrane binding with phospholipase D. The presence of Ca2+ protects the membranes from such a degradation. High Ca2+ concentrations cause a "pseudo" stabilization of mitochondrial polyenzyme systems with respect to phospholipase D. In fact, a decrease in phospholipase binding with mitochondrial membranes takes place at 30 mM and higher concentrations of CaCl2, which is due to the intensive phospholipid degradation at the initial reaction step. Optimal Ca2+ concentration range for the activation of phospholipase D is 2-5 mM. It does not coincide with Ca2+ concentration values necessary for the phospholipase activation with "disorganized substrates" (30-60 mM). Combined effect of Ca2+ and phospholipase D on outer and inner NADH oxidation pathway manifests differently. The inner pathway (the respiration chain) is more subjected to the lytic action of the enzyme, while the oxidation rate through the outer pathway increases under low phospholipase D concentrations, and the oxidation stops only under high enzyme concentration in the presence of Ca2+ ions. The data are also given, demonstrating that some effects, which have been early considered to be related to the effect of Ca2+ on mitochondria, are really due to changes under the lytic effect of endogenous phospholipases, Ca2+ being the enzyme activator.


[Specificity of neutral ribosomal protease]. The specificity of the ribosomal proteinase was studied using a variety of substrates: nascend peptides, ribosomal proteins, B-chain of insulin and some synthetic peptides (the heptapeptide Gly-Phe-Phe-Tyr-Thr-Pro-Lys; the hexapeptide Gly-Phe-Leu-Gly-Phe-Leu and the CBZ-hexapeptide; the tripeptide Phe-His-Leu and the CBZ-tripeptide). It was shown that in the heptapeptide tested the enzyme cleaved most rapidly the Phe-Tyr bond; the Phe-Phe bond was cleaved less rapidly. The rest of the peptide bonds in the heptapeptide were also cleaved and by the end of the incubation the cleavage was complete. All the other substrates tested also underwent complete degradation. The data obtained allowed us to classify the enzyme with the group of endopeptidases with broad specificity of action. The possibility cannot be excluded that the broad specificity observed is due to the presence of more than one enzyme on the polyribosomes.


[Effect of melitten from bee venom on mitochondrial functions]. Effect of different concentrations of bee venom melittin on respiration, mitochondrial oxidative phosphorylation, and permeability of mitochondrial inner membranes for different ions is studied. Low melittin concentrations (1-2 mcM) increased in several times the rate of H+, K+, Na+ ions and Tris transport, in a lesser degree--bivalent ions and Cl- transport and did not affect the permeability for succrose. Thus, the uncoupling effect of low melittin concentrations on mitochondrial energetic apparatus is due to unspecific increase of inner membrane permeability. High melittin concentrations (50-100 mcM) inhibited mitochondrial respiration due to disturbances of membrane and organized respication complexes structures.


[Creatine phosphate synthesis coupled to glycolytic reactions in heart cell cytosol]. It is shown that a cytosolic fraction of proteins from rat heart, containing all glycolytic enzymes and creatine phosphokinase (CPK) in natural proportions, catalyses in the presence of creatine (Cr) the intensive creatine phosphate (CP) synthesis coupled to glycolytic depletion of glucose, fructose-1,6-diphosphate (FDP) and phosphoenolpyruvate (PEP). The ratio of CP to lactate produced was 1.0 in the case of PEP as glycolytic substrates. In the CP production process the CPK reaction was not the rate limiting step: the mass action ratio for CPK was equal to the apparent equilibrium constant for this reaction, and the maximal rate of the CPK reaction exceeded the observed rate of glycolysis by a factor 6. It is concluded that in such a system the components of the CPK reaction are in quasiequilibrium and the mechanism of CP synthesis can be considered to be a continuous decrease in ADP concentration due to its phosphorylation in the glycolytic reactions, ATP concentration being constant due to its continuous utilization and resynthesis, this leading to an increase in CP concentration. The possible role of the CPK system in regulation of glycolysis in muscle cells is discussed.


[Improved procedure for purification of aspartate transaminase from chicken heart cytosol. Characterization of the enzyme]. The purification procedure reported includes fractionation of water extract from chicken hearts with ammonium sulfate, fractional precipitation with ethanol, chromatography on Whatman CM-52 cellulose and crystallization. Specific activity of the pure crystalline enzyme was 234 micromoles.min-1.mg-1, as determined in the coupled assay with malate dehydrogenase (pH 7.5; 25 degrees). The amino acid composition of the enzyme was determined and the circular dichroism spectrum was recorded in the 200-250 nm range. The spectrum shows two negative bands with extrema at 208 and 220 nm. From the circular dichroism data it is estimated that aspartate transaminase contains approximately 40% alpha-helix and 10% beta-structure.


[Ferredoxin-dependent glutamate synthase of Chlorella]. Ferredoxin-dependent glutamate synthase has been found in cells of thermophylic Chlorella strain Ch. pyrenoidosa 82T. The enzyme is active with its own ferredoxin and that of Spirulina. Glutamate synthase activity increases during nitrogen starvation and than decreases in the course of successive ammonium assimilation. The scheme of ammonium assimilation in Chlorella pyrenoidosa 82T cells is proposed.


[Comparative study in nuclear and cytoplasmic RNA species of mouse liver, Guelstein ascites hepatoma 22A and liver of tumor-bearing animals]. A comparative study on nuclear and cytoplasmic DNA-like RNA species from normal liver, malignant Guelstein hepatoma 22A and liver of tumor-bearing animals was carried out. The nuclear RNA's were found to be poorly and rapidly labelling, the latter comprising a lesser proportion in hepatoma as compared with a normal liver. The comparison of labelling rates of nuclear and cytoplasmic RNA species shows that the nucleus-to-cytoplasme RNA transport is accelerated in hepatoma. Besides, cytoplasmic DNA-like RNA's are more heterogeneous in hepatoma and liver of tumor-bearing animals than in normal liver cells.


Balance of net base in the rat. IV. Effects of oral calcium and phosphate loading. Mineral and net base balances were studied in groups of male weanling Wistar rats given oral loads of calcium chloride, monocalcium phosphate plus monosodium phosphate, and disodium phosphate plus monopotassium phosphate, respectively. A group of adult nongrowing rats loaded with calcium chloride was included for comparison. In response to CaCl2 loading, gastrointestinal net base absorption was inhibited due, largely, to luminal precipitation of tertiary phosphates of calcium and magnesium. In the weanling animal, however, a rise in the rate of renal net acid excretion matched the concomitant decrement in the rate of net base absorption, permitting of continued skeletal net base storage. Similarly, in the adult animals augmented renal net acid excretion offset a positive rate of gastrointestinal net acid absorption with a resultant (normal) zero net base balance. Loading with monocalcium phosphate and disodium phosphate at a constant oral net base intake did not influence the overall net base balance, but disodium phosphate loading caused significant sodium retention.


Source of fetal-stored lipids during maternal starvation in rabbits. The effect of 48 h maternal starvation on the composition of fetal rabbit brown and white adipose tissue was examined. Compared with fed control rabbits, adipose tissue triglyceride fatty acids took on a composition more like that of maternal plasma free fatty acids (FFA), whose concentration more than doubled after 48 h starvation. It is concluded that maternal FFA contribution to the fetal lipids increases during starvation and certain fetal acids, in particular linoleic acid, may in the fed state be derived from maternal lipids other than the FFA.


Basic cardiovascular parameters in the underweight neonatal swine. Some hematological and cardiovascular parameters of the underweight neonatal piglets have been compared with normal-weight 1 and 7-day-old swine (Sus scrofa domestica). The underweight swine had a significantly lower leukocyte count, plasma protein level and blood glucose level, but a significantly higher plasma LDH level. Heart rate and arterial blood pressure were significantly lower in the underweight group. Based on the observed results it was postulated that the piglets born with a low body weight could also be physiologically immature since the cardiovascular parameters measured approximated those reported for normal fetuses of the same weight. Further studies are required to ascertain if a functional immaturity persists in the neonatal animals.


Cerebral oxidative metabolism during intrauterine growth retardation. Cerebral oxidative metabolism during intrauterine growth retardation was investigated utilizing a pregnant-rat model. Dams were subjected to unilateral uterine artery ligation on the 17th day of gestation. At term, they were sacrificed by decapitation and the fetuses delivered by cesarean section. Body and brain weights of fetuses from ligated uterine segments were smaller than those of offspring from nonligated horns of the experimental rats or those from sham-operated dams. Blood glucose at birth was reduced by 25% in growth-retarded fetuses. Cerebral oxidative metabolites, including glycogen, glucose, lactate, ATP, and phosphocreatine, were not different from control levels. These findings suggest that neither tissue hypoxia nor deficient glucose delivery to brain can account for the stunted cerebral growth observed in fetuses following uterine artery ligation.


Effect of feeding on the cessation of transport of macromolecules by enterocytes of neonatal piglet intestine. To elucidate further the role of digesta in the cessation of transport of macromolecules to the blood by enterocytes of neonatal piglet small intestine, a portion of the ileum was surgically isolated and vented to the exterior. The ability of this isolated intestine to transport macromolecules was compared with that of the intestine remaining in the digestive pathway in the same piglet. The isolated intestine ceased transporting macromolecules at the same time as the intestine in the digestive pathway, thus implicating a humoral signal that is responsible for the cessation of transport.


The developmental response of the ductus arteriosus to oxygen. We studied the isometric contractile effects of increased PO2 on isolated rings of lamb ductus arteriosus (from three different gestational age groups). When rings were stretched to initial lengths that result in a maximal contractile response for rings in that age group, the oxygen-induced contraction was 5.91 +/- 0.72 g/mm2 (+/-SEM, n = 18) in animals older than 135 days, 5.55 +/- 1.23 g/mm2 (n = 18) in animals between 111 and 130 days, and 3.85 +/- 0.75 g/mm2 (n = 19) in animals between 87 and 110 days. Only in the most immature vessels could a decrease in the tissue's response to oxygen be observed.


Is there a blood-brain relationship for saturated fatty acids during development? Transport of subcutaneously injected [1-14C]-stearic acid through the blood-brain barrier is compared with endogenous biosynthesis (within the brain) during postnatal brain development in mice. The uptake is very important during glial cell multiplication and myelination; endogenous microsomal synthesis is most active during myelination, soluble de novo mechanism is prominent during cell multiplication (mitochondrial systems are not directly related to these events). A parallel is drawn between myelin fatty acids, microsomal synthesis and uptake from the blood.


Integrated cardiovascular responses to combined somatic afferent stimulation in newborn piglets. Heart rate, mean aortic pressure and arterial flow responses to interactions of afferent stimulation of the sciatic (SNS) and median nerve of the brachial plexus (BNS) were studied in 30 newborn piglets under halothane-N2O anesthesia. High frequency or intensity SNS or BNS stimulation resulted in pressor responses accompanied by significant increases in the femoral flow and carotid and renal resistance. Combined stimulation produced responses smaller than the estimated sum of the responses. Low frequency or intensity SNS or BNS resulted in depressor responses accompanied by significant decreases in mean femoral flow without change in heart rate; combined stimulation produced responses smaller than the estimated sum. When pressor and depressor patterns of stimulation were combined, pressor responses always dominated. The absence of facilitation to any combination of interactions implies that the cardiovascular regulatory system is not fully developed at birth and undergoes, therefore, postnatal maturation.


Influence of increasing age on lethality induced by carbon monoxide or hypoxic hypoxia. Mice ranging in age from 2 to 150 days of age were exposed to 2,000 ppm carbon monoxide (CO) or 7.5% O2. 2-day-old mice were more resistant than older animals to the lethal effects of both CO and hypoxic hypoxia. The oldest age group (150 days) were also found to be more resistant than young adult mice to the lethal effects of both CO and hypoxic hypoxia. The role of body temperature in the age-dependent susceptibility was studied by altering the environmental temperature. Neonatal mice remained resistant to the lethal effects of CO until the environmental temperature reached 35 degrees C at which time the death rate of neonatal mice equaled that of the adult mice in 30 degrees C environment.


Isozyme profiles of lactic dehydrogenase and creatine phosphokinase in neonatal mouse hearts. Isozyme profiles of lactic dehydrogenase (LDH) and creatine phosphokinase (CPK) were determined in cardiac tissue of mice during postnatal development. LDH isozymes 1 and 5 showed a definite developmental change, achieving the adult values by 20 days of age, while the other three isozymes showed no change. During the first 2 postnatal weeks, a developmental change was seen in the activities of the 'mito' and MB isozymes of CPK, with the adult profile being established by day 20. CPK isozymes MM and BB did not change during this interval.


Dietary influences on fatty acid metabolism in the liver of the neonatal lamb. A "protected" polyunsaturated fatty acid supplement was fed to ewes during the last 8 weeks of pregnancy. The effect of this dietary supplement on the essential fatty acid composition of the liver phospholipids and associated changes in the liver delta9- and delta6-desaturase activities were investigated and compared with the effects of directly dosing the newborn lambs for 8 days with an unprotected polyunsaturated oil, maize oil. The maternal dietary supplement produced significant changes in the essential fatty acid composition of the neonatal lamb liver phospholipids. Although the liver delta6-desaturase activity in these animals was also significantly higher than in the lambs from control ewes, the delta9-desaturase was unaffected by maternal dietary supplementation. Direct dosing of the newborn lambs with maize oil failed to produce any signficant changes either in the liver phospholipid fatty acid composition or in the delta9- and delta6-desaturase activities. These results are discussed in terms of the dietary control of liver desaturase enzyme systems.


Effect of maternal glucose infusions on fatty acid transport across the placenta in rabbits. Glucose infusions given intravenously to 28-day-pregnant rabbits increased maternal and fetal plasma immunoreactive insulin levels and decreased maternal concentrations of circulating free fatty acid (FFA). Fetal plasma FFA were only slightly depressed and umbilical venous-arterial concentration differences were unchanged both for total FFA and for individual fatty acids in the FFA fraction. The mean umbilical venous concentration was twice that of maternal levels in the infused group, but about the same concentration in untreated rabbits. It is concluded that the infused glucose, or the high insulin levels provoked by it, or both, caused an increased flow of FFA to the fetus, probably from sources other than the maternal plasma FFA.


Pulmonary and circulatory function in preterm lambs treated with hydrocortisone in utero. The effects of the in utero intravenous administration of hydrocortisone on postnatal lung function and pulmonary and systemic hemodynamics were studied in preterm fetal lambs and compared with those of non-treated animals of similar gestational ages. The results indicate that steroid-induced changes in lung pressure volume curves, although statistically significant, did not render the pretreated fetuses capable of surviving without ventilatory assistance. In addition, the ductus arteriosus in the steroid-treated lambs at 2 h of age was functionally closed or constricted regardless of gestational age. In contrast, in the untreated lambs the ductus arteriosus was widely patent and, especially in lambs of less than 120 days gestation, there was invariably a large left-to-right ductal shunt.


The development of DT-diaphorase in rat liver and its induction by benzo(a)pyrene. The development of cytosolic DT-diaphorase--NAD(P)H dehydrogenase, quinone, EC 1.6.99.2--and its induction by benzo(a)pyrene has been studied in rat liver. DT-diaphorase belongs to the late suckling cluster, because the largest increase in activity can be observed 18 days after birth. A considerable activity is present, however, in the neonatal period. The activity of the enzyme can be prematurely induced by benzo(a)pyrene. A lag phase of 10 h can be observed before the activity of DT-diaphorase starts to increase. This increase in activity proved to be sensitive to inhibitors of mixed-function oxydase and RNA and DNA synthesis.


Degradation of radioactively labelled protein in the small intestine of the suckling rat. The absorption of 125I-labelled bovine IgG, after oral and intraluminal administration to young rats, has been followed by gel filtration and quantitatively by TCA precipitation. After intraluminal administration of the radioactive dose into the proximal small intestine most of the absorbed dose could be accounted for in a protein-bound form and the bulk of this radioactivity corresponded to native protein. Catabolism of the standard dose was far more efficient in the ileal regions of the small intestine, only 10% of the absorbed dose was transmitted as intact protein and large degradation products. Investigations on the attachment and release of labelled proteins from different sections of the small intestine of the young rat have also been recorded.


Effect of thyroxine on permeability of the neonatal rat lung to drugs. The effect of thyroxine (1-2 microgram/g i.p. on days 1-4 after birth) on development of adult-type permeability characteristics in the lung was investigated in rats 6-18 days of age. In both treated and control rats, the lipid-soluble drug procaine amide was absorbed at similar rates in all age groups. In contrast, in thyroxine-treated animals, pulmonary absorption rates for the lipid-insoluble compounds mannitol and p-aminohippuric acid declined to adult levels at age 6-12 days, 6 days earlier than in controls. Thyroxine treatment thus accelerates development of adult permeability characteristics in the pulmonary epithelium.


Differences in platelet monoamine oxidase activity in subgroups of schizophrenic and depressive disorders. Platelet monoamine oxidase (MAO) activity was measured in patients with nonaffective schizophrenic disorders (i.e., without prominent symptoms of depressions or manias), and in patients with schizophrenia-related depressions. MAO activity was significantly lower than control values in a subgroup of 16 patients with nonaffective schizophrenic disorders (most of whom were paranoid) characterized by the presence of auditory hallucinations and delusions. Platelet MAO activity was not reduced in 16 other nonaffective schizophrenic patients without auditory hallucinations. Platelet MAO activity was significantly higher than control values in a group of 8 depressed patients with schizophrenia-related depressions characterized by the presence of chronic asocial, eccentric, or bizarre behavior. These findings of differences in platelet MAO activity in clinically defined subgroups of nonaffective schizophrenic disorders and the schizophrenia-related depressive disorders may help to account for some of the discrepancies in findings among the various studies of platelet MAO activity in schizophrenic and affective disorders.


Altered metabolism of the methionine methyl group in the leukocytes of patients with schizophrenia. Previous work has indicated that abnormal methylation processes may be associated with schizophrenia. In this study, leukocytes from patients with schizophrenia were incubated with methyl-14C-L-methionine and the evolved 14CO2 measured. With increasing concentration of methionine, the evolved 14CO2 was lower in the patients than in normal control subjects. The incorporation of 14C into protein was the same in both groups, and when carboxyl-14C-L-methionine was used the evolved 14CO2 was the same in both groups, thus excluding the possibility that altered incorporation into protein or oxidation of the methionine molecule as a whole were responsible. The observed differences in methionine-methyl metabolism suggest that an abnormality in transmethylation processes or in oxidation of the methyl group to CO2 is associated with schizophrenia. That this occurs in a peripheral tissue indicates that the abnormality is not restricted to the central nervous system.


Effect of methionine-loading on methyl group synthesis and activation in rat brain and liver. Much greater increases in S-adenosylmethionine concentrations are observed in the liver in response to methionine-loading than in the brain due to differences in the methionine adenosyltransferase activities in these tissues. Liver methione adenosyltransferase exhibits a bimodal saturation curve with a nonlinear Line-weaver-Burk plot, indicating that high methionine concentrations are required for saturation. In the brain the methionine adenosyltransferase is saturated in vitro at a methionine concentration less than the normal physiological concentration. The increased S-adenosylmethionine concentrations in the livers of methionine-treated rats also account for the observed inhibition of N5,N10-methylenetetrahydrofolate reductase activity in this tissue. No inhibition of this enzyme is observed in the brain of methionine treated animals. Nor are S-adenosylmethionine concentrations increased significantly in brain. Serine hydroxymethyltransferase activity responds to methionine-loading by decreasing in brain and increasing in liver.


Serotonin, folic acid, and uric acid metabolism in the diagnosis of neuropsychiatric disorders. Metabolic compensation appears possible within the serotonergic, folate, purine system and it seems possible that clinical illness may result when the system can no longer compensate. For example, elevated serotonin, induced by stress accumulation of tryptophan, could be compensated by a lowered folate ratio, normalizing the beta-carboline index and preventing hallucinations. Conversely, deficient serotonin, induced by a psychological loss or transport deficit, could be compensated by raising the folate ratio, which would normalize the beta-carboline index and prevent further depression. Increased purine turnover would seemingly lower the folate ratio, compensating perhaps for hallucinatory activity or mania. Several genetic defects of enzymes or transport proteins could seemingly preclude normal compensations within the system.


Dopamine-beta-hydroxylase in the cerebrospinal fluid of psychiatric patients. The activity of dopamine-beta-hydroxylase (DBH) in cerebrospinal fluid (CSF) from 59 psychiatric patients has been analyzed by a highly sensitive radio-enzymatic assay. There was no sex difference in DBH, but there was a significant positive correlation with age. Probenecid administration had no effect on CSF DBH. DBH in CSF correlated positively (r = 0.60) with the plasma enzyme. Among patients hospitalized for major depressive disorder, unipolar or bipolar, schizo-affective disorder, schizophrenia, alcoholism, or personality disorders there were no significant between-group differences. Among the patients with bipolar affective disorder, DBH activity from manic patients was significantly lower than that from depressed or euthymic patients. The results are discussed with reference to the theory that the amount of DBH in CSF may serve as an indicator of central noradrenergic activity.


N5,10-methylenetetrahydrofolate reductase activity in autopsied brain parts of chronic schizophrenics and controls and in vitro tryptoline formation. We and others have shown that in vitro tryptoline (tetrahydro-beta-carboline) formation accounts for the apparent-N-methylating activity of a brain enzymatic preparation using 5-methyltetrahydrofolic acid (5-MTHF) as a cofactor and tryptamines or catecholamines as substrates. This paper demonstrates that N5,10-methylenetetrahydrofolate reductase (methylene reductase) is responsible for this in vitro tryptoline formation with human brain enzymatic preparations. Others have described a folate-responsive psychosis which was associated with markedly reduced methylene reductase activity. Therefore, we also have examined this enzymatic activity in autopsied brains from chronic schizophrenics and controls. There were no statistically significant differences between activities for schizophrenics and controls in the six brain regions studied. Thus, although it is possible that some subgroup of schizophrenics may be characterized by abnormal methylene reductase activity, there does not appear to be a general association between the two.


Aluminum levels in brain in Alzheimer's disease. In both human Alzheimer's disease and aluminum encephalopathy of animals, changes are observed in neurofibrillary structures. We have found that brains from Alzheimer patients contain approximately 1.4 times the aluminum level found in a control series. Some possible methodological problems are discussed. We have proposed a plausible chemical mechanism for the changes of aluminum encephalopathy.


EEG measures of functional tolerance to alcohol. The literature suggests that alcohol ingestion produces characteristic alterations of sleep physiology and evoked response in alcoholics. Studies of alcohol withdrawal indicate that for some alcoholics residual functional tolerance remains apparent for an indefinite period. Low amounts of slow wave sleep (SWS) appear to be one of the physiological concomitants of the residual tolerance. Visual evoked responses were recorded from two small groups of inpatient alcoholics identified as normal or low SWS during a sober period. Alcohol ingestion produced no significant changes of evoked response parameters. Alcohol withdrawal produced significant augmentation of early component amplitude for the low SWS group only.  These data suggest that low SWS and augmented primary component amplitude may be physiological correlates of functional tolerance to alcohol.


EEG signs of brain impairment in alcoholism. EEGs were recorded for two groups of chronic alcoholics who scored at opposite extremes on the Shipley Institute of Living Scale. The groups were matched in terms of age and drinking history variables and were compared to age-matched control subjects for left and right precentral (F-T) and postcentral (C-O) placements. Significant ANOVA findings were obtained primarily in high-frequency bands in the three group comparison. A significant linear trend was found for power as a function of degree of impairment from controls to moderately impaired alcoholics to severely impaired alcoholics in frequency bands above 14 Hz. The trend was most pronounced in the F-T derivations. Implications of the findings with respect to cortical atrophy in alcoholism are discussed.


Changes in cerebral hemispheric lateralization with hypnosis. Cerebral hemisphere dominance was measured in 20 subjects before, during, and after hypnotic suggestion. During hypnosis, subjects demonstrated lower right ear/left hemisphere laterality scores on a dichotic listening task compared to pre- and posthypnosis periods. These results support the view that hypnosis facilitates greater participation of the right cerebral hemisphere in cognition and may partially account for several well known hypnotic effects.


Accelerated recovery of post-dialysis plasma carnitine fall by oral carnitine. Plasma free carnitine in 6 chronic uremic patients fell 73% during hemodialysis. The recovery time was 6 h with placebo and only 2 h when dl carnitine (3 g oral) was taken at the end of dialysis.


A history of the Reed-Sternberg cell.

A history of the Reed-Sternberg cell. The diagnosis of Hodgkin's disease continues to depend upon the finding of Reed-Sternberg cells in an appropriate histological setting. The cellular origin of the Reed-Sternberg cell is, however, controversial, and the relationship of Hodgkin's disease to the "non-Hodgkin" lymphomas remains uncertain. In the last decade techniques derived from basic immunology have added a new dimension to our understanding of the cellular origin of the "non-Hodgkin" lymphomas. Our concepts of Hodgkin's disease may require modification along similar principles.


Measure of total body water, using infrared spectrometry of heavy water. The total body water can be assayed by the measurement of the diffusion space of heavy water. A well reproducible and inexpensive method is the infrared spectrometry, using two differential comparisons.


alpha-Tocopherol pretreatment increases adriamycin bone marrow toxicity. Alpha-tocopherol has been shown to increase survival duration and decrease cardiotoxicity and cell membrane lipid peroxidation in adriamycin treated leukemic mice. We have studied the interacting effects of free alpha-tocopherol-adriamycin or alpha-tocopherol acetate-adriamycin on the latter's inhibition of mouse bone marrow (NCFU) and P388 leukemic (LCFU) stem cell growth. Free alpha-tocopherol or alpha-tocopherol acetate, 85 IU, was given i.p. to normal or leukemic DBA/2 mice 24 hours prior to IV adriamycin, 2--12 mg/kg. NCFU and LCFU assays were carried out as previously described. Both free alpha-tocopherol and alpha-tocopherol acetate caused a significant ( p less than .02) increase in adriamycin toxicity to NCFU, whereas alpha-tocopherol acetate did not significantly increase adriamycin's inhibition of LCFU. We conclude that free alpha-tocopherol or alpha-tocopherol acetate may cause a potentiation of adriamycin's bone marrow toxicity.


An immunologic comparison between bone marrow and spleen-derived pluripotent hemopoietic stem cells (CFU-S) of mouse : effect of rabbit anti-mouse brain serum. We used rabbit anti-mouse brain serum (RAMBS), with known activity against pluripotent hemopoietic stem cells (CFU-S) of mice, to compare the proportions of CFU-S from bone marrow and spleen which express the brain-associated CFU-S antigen(s). Eighty percent of marrow and 77% of spleen-derived CFU-S were inactivated by RAMBS. This suggests that these two populations of CFU-S are antigenically similar with respect to the brain-associated CFU-S antigen(s); this is in contrast to functional differences which are known to exist between the two populations of CFU-S.


Antiviral activity in sera of patients with influenza infection. An interferon like activity was investigated in the sera of patients, very early during an Influenza A or B infection. A such substance was significantly more frequent among the patients who shed a Myxovirus Influenza than among the patients without virus isolation in the nasopharynx. The following relations are discussed : either is the interferon production merely associated without effect on the virus level? Or, on the other hand, in some cases is the rate or virus multiplication strictly directed by this interferon production? This study don't allowed to choose one of these hypothesis.


Lymph nodes in congenital osteopetrosis of the op rat (ultrastructural study). The electron microscopic study of lymph nodes from osteopetrotic op/op rats demonstrates the existence of an active lymphopoiesis and granulopoiesis. At an advanced stage of the disease, lymphopoiesis is associated to a granulopoiesis and to plasmacytosis.


The significance of ferritin in malignant diseases. Ferritins are a group of isometric proteins having an important function in iron storage and metabolism and are found in high concentration in the liver, spleen and bone marrow. Acidic isoferritins are found in human fetal liver, primary mammary, gastric and pancreatic carcinomas, and are termed carcinofetal ferritins. Elevated levels of serum ferritin were found in patients with various malignant diseases such as Hodgkin's disease, chronic myeloblastic, granulocytic and lymphatic leukemias and myeloblastosis, in patients with breast cancer, multiple myeloma, malignant lymphoma, carcinoma of the gastro intestinal tract and germinal cell tumors of the testis. Recently a subpopulation of circulating T lymphocytes bearing surface ferritin was found in patients with breast cancer and untreated Hodgkin's disease. No such lymphocytes were demonstrated in normals or in patients with benign breast disease. The appearance of such subpopulation in the circulation is an early manifestation of the neoplastic disease, and its identification may provide a tool of potential diagnostic and prognostic importance in the management of Hodgkin's disease and breast cancer.


A micromethod for the evaluation of hemoglobin A1c: technique and preliminary results. A microtechnique of column chromatography on a Biorex 70 resin monitored by permanent recording of the effluent o.d., permits to obtain the percent of Hb A1C in an hemolyzate within 1.5 hr (in the place of 6 hrs in the usual techniques). This evaluation was carried out in 18 normal subjects and 32 patients suffering from diabetes mellitus and was repeated several times in 10 patients. The average level in the normal subjects was 5.01% (3.2 to 6.1%), in the equilibrated patients with a glycemia under 2 g/l: 6.44% (5.74 to 7.14%) and in the poorly equilibrated patients: 8.9% (5.5 to 15.3%). Hemoglobin A1C appears as a valuable index of sugar metabolic equilibrium.


Human peripheral Nullymphocytes: ultrastructural aspects of the "K" cell effect against a melanoma target cell. A null cell fraction was isolated from human peripheral blood by Ficoll density gradient centrifugation followed by removal of mononuclear phagocytes, passage through Ig-antiIg columns and sedimentation of E-rosette forming T cells. In contrast to the T cell fraction in the Null cell population exhibited cytotoxic activity against antibody-sensitized human melanoma target cells (ADCC reaction). This activity could be attributed to a low affinity Fc-receptor bearing cells present in the Null cell preparation. At the ultrastructural level in 2 h ADCC reaction most tumor cells were surrounded by up to 10 lymphoid cells which showed narrow junctions with parallel plasma membranes and local evaginations of lymphoid cells into recessus of the target melanoma cells. The mononuclear cell type found in close contact with the antibody-sensitized target cells had the following morphological criteria: 8 to 10 mu diameter, irregular nucleus, discrete rough endoplasmic reticulum, isolated ribosomes, cytoplasmic organelles concentrated under a ruffling membrane in the contact area with the tumor cell.


Examination of transport equations pertaining to permeable elastic tubules such as Henle's loop. The transport equations applicable to loops of Henle and similar elastic permeable tubules were re-examined to assess the effect of radial transport resistance in the lumen and tubule geometry on solute transport. Active transport at the wall as well as external gradients equivalent to a 2--1,000-fold concentration increase per centimeter of distance were considered. Wall permeabilities and active transport constants were varied up to 2 . 10(-2) cm/s. It is shown that for conditions applicable to the loop of Henle, resistance to radial solute transfer in the lumen is negligible, both for passive and active transmural transport with concomitant water flux, and that axial dispersion further reduces that resistance. These conclusions apply equally to conical and elliptical geometries likely to arise in loop operation. The validity of Poiseuille's equation for these geometries is discussed. Ii is concluded that the one-dimensional transport equations are a valid representation of loop operation.


Theory of fluorescence polarization in magnetically oriented photosynthetic systems. Many cells and cell fragments are known to assume specific alignments with respect to an applied magnetic field. One indicator of this alignment is a difference between the intensities of fluorescence observed in polarizations parallel and perpendicular to the magnetic filed. We calculate these two intensities using a model that assumes axially symmetric membranes and that covers a wide variety of shapes from flat disk to right cylinder. The fluorescence is assumed to originate at chromophores randomly exicted but nonrandomly oriented in the membranes. The membrane alignment is assumed to be due to the net torque on a nonrandom distribution of diamagnetically anisotropic molecules. The predicted results are consistent with most magnetoorientation data from green cells, but we are able to show that Chlorella data are not consistent with the hypothesis that the membranes have, and maintain, a cuplike configuration.


Modeling rigor cross-bridge patterns in muscle I. Initial studies of the rigor lattice of insect flight muscle. We have undertaken some computer modeling studies of the cross-bridge observed by Reedy in insect flight muscle so that we investigate the geometric parameters that influence the attachment patterns of cross-bridges to actin filaments. We find that the appearance of double chevrons along an actin filament indicates that the cross-bridges are able to reach 10--14 nm axially, and about 90 degrees around the actin filament. Between three and five actin monomers are therefore available along each turn of one strand of actin helix for labeling by cross-bridges from an adjacent myosin filament. Reedy's flared X of four bridges, which appears rotated 60 degrees at successive levels on the thick filament, depends on the orientation of the actin filaments in the whole lattice as well as on the range of movement in each cross-bridge. Fairly accurate chevrons and flared X groupings can be modeled with a six-stranded myosin surface lattice. The 116-nm long repeat appears in our models as "beating" of the 14.5-nm myosin repeat and the 38.5-nm actin period. Fourier transforms of the labeled actin filaments indicate that the cross-bridges attach to each actin filament on average of 14.5 nm apart. The transform is sensitive to changes in the ease with which the cross-bridge can be distorted in different directions.


A theoretical study of Na+ and Mg+2 binding to the carbonyl oxygen of N-methyl acetamide. Molecular orbital calculations (CNDO/2) are reported for the interaction of Na+ and Mg+2 with the carbonyl of a model peptide moiety (N-methyl acetamide) as a function of the C--O ... Me distance and angle and with variation in the number of ligands for the purpose of determining the steepness of the distance dependence of the binding energy and for the purpose of determining the reduction of charge on the ion with increasing numbers of ligands. The greater energy derived on divalent ion binding and the steeper distance dependence indicate that selective, divalent over monovalent, ion binding will occur whenever the liganding system can provide a coordination shell of appropriate dimension. The calculations indicate that the preferred C--O ... Me angle is not 180 degrees. Of particular note is the decrease of charge on the cation on binding to N-methyl acetamide. One ligand bound to Na+ reduces the charge from 1.0 to 0.7 electron units and four ligands bound to Mg+2 reduces the charge from 2.0 to 0.7 electron units. This is of primary significance in carrier and channel mechanisms for cation permeation of lipid membranes; and although the numerical values are qualitative, the implication is for allowance of multiple occupancy of channels by monovalent cations.


Evidence for a discrete charge effect within lipid bilayer membranes. A high amplitude voltage step technique has been used to meausre the surface density of dipicrylamine anions adsorbed at the surfaces of lipid bilayer membranes. Accompanying low amplitude measurements have determined the relaxation time for transient current flow across the membranes, a parameter governed by the height of the central energy barrier which dipicrylamine anions must cross in moving from one membrane surface to the other. Measured relaxation times and surface charge densities have been related by a quasi-continuum model of the discrete charge effect, which predicts that the membrane central barrier height will increase with increasing density of adsorbed surface charge. The experimentally determined relationship is in satisfactory agreement with the predictions of the model. The model does not provide a complete description of the membrane/solution interface, however, because it cannot be applied to the description of previously measured isotherms for the adsorption of dipicrylamine anions onto bilayer membranes surfaces. Possible reasons for this discrepancy are discussed.


Solution conformation of peptides by the intramolecular nuclear Overhauser effect experiment. Study of valinomycin-K+. This study demonstrates how the intramolecular nuclear Overhauser effect (NOE) experiment can be employed quantitatively to select from a set of possible conformations for a peptide or a protein the particular conformation (or a group of conformations) most consistent with the data. This procedure is demonstrated on a model depsipeptide system--valinomycin K+ in CDCl3--for which the solution conformation has been inferred by other methods. The NOE enhancements are very sensitive to the conformations assumed by this antibiotic. It is shown that the set of conformations, collectively labeled as A2 (including the X-ray crystallographic structure) gives a very good description of the NOE enhancements. The structure proposed by Bystrov et al. (1977. Eur. J. Biochem. 78:63) for the uncomplexed valinomycin in nonpolar solvents is also consistent with the experimental data on the potassium complex. Using statistical hypothesis testing involving the Hamilton R-factor ratio criterion, all the other models have been rejected as inconsistent with the experimental data. A general formalism is presented for describing the NOE effects in isotropically reorienting molecules. The formalism is not restricted to the extreme narrowing limit of the rotational correlation times and hence applies to both small and large molecules. Some of the factors that can influence the NOE measurements, viz. anisotropic rotational diffusion, conformational averaging, and nuclear spin diffusion, have been considered in this study.


Conformation of mononucleotides and dinucleoside monophosphates. P[H] and H[H] nuclear Overhauser effects. The phosphorus-proton nuclear Overhauser effect (NOE) was used to investigate the quantitative distribution of rotamers about the C3'--O3' bond (phi') of 3'-AMP and 2',3'-cyclic-CMP and the C4'--C5', C5'--O5' bonds (psi, phi) of 5'-AMP. Phosphorus-proton and proton-proton NOE's were used to provide a qualitative insight into the backbone conformation and the glycosyl angle torsions of adenosylyl-(3' leads to 5')-adenosine (ApA). The major psi rotamer in 5'-AMP is the 60 degree (gg) form, while the major phi rotamer is the 180 degrees (g'g') form. The constrained model, 2',3'-cyclic-CMP, manifests the C3'endo furanose pucker predominantly. The results from these two models are consistent with nuclear magnetic resonance (NMR) J coupling analyses. The phi; distribution of 3'-AMP is dominated (77%) by the 180 degrees g- rotamer. The 3'-AMP results are consistent with phosphorus-hydrogen coupling constant analyses, but do not accord with phosphorus-carbon coupling constant results. The phosphorus-proton NOE reveals that the phosphorus of ApA occupies a region of conformation space not seen in 5'-AMP. The proton-proton NOE on APA shows a significant portion of syn rotamer in both X distributions and detects a cross-purine ring interaction consistent with base stacking known to exist in this system.


Amide proton spin-lattice relaxation in polypeptides. A field-dependence study of the proton and nitrogen dipolar interactions in alumichrome. The proton nuclear magnetic resonance (NMR) spin-lattice relaxation of all six amides of deferriferrichrome and of various alumichromes dissolved in hexadeutero-dimethylsulfoxide have been investigated at 100, 220, and 360 MHz. We find that, depending on the type of residue (glycyl or ornithyl), the amide proton relaxation rates are rather uniform in the metal-free cyclohexapeptide. In contrast, the (1)H spinlattice relaxation times (T(1)'s) are distinct in the Al(3+)-coordination derivative. Similar patterns are observed in a number of isomorphic alumichrome homologues that differ in single-site residue substitutions, indicating that the spin-lattice relaxation rate is mainly determined by dipole-dipole interactions within a rigid molecular framework rather than by the specific primary structures. Analysis of the data in terms of (1)H-(1)H distances (r) calculated from X-ray coordinates yields a satisfactory linear fit between T(1) (-1) and Sigmar(-6) at the three magnetic fields. Considering the very sensitive r-dependence of T(1), the agreement gives confidence, at a quantitative level, both on the fitness of the crystallographic model to represent the alumichromes' solution conformation and on the validity of assuming isotropic rotational motion for the globular metallopeptides. An extra contribution to the amide proton T(1) (-1) is proposed to mainly originate from the (1)H-(14)N dipolar interaction: this was supported by comparison with measurements on an (15)N-enriched peptide. The nitrogen dipolar contribution to the peptide proton relaxation is discussed in the context of {(1)H}-(1)H nuclear Overhauser enhancement (NOE) studies because, especially at high fields, it can be dominant in determining the amide proton relaxation rates and hence result in a decreased effectiveness for the (1)H-(1)H dipolar mechanism to cause NOE's. From the slope and intersect values of T(1) (-1) vs. Sigmar(-6) linear plots, a number of independent estimates of tau(r), the rotational correlation time, were derived. These and the field-dependence of the T(1)'s yield a best estimate <tau(r)> approximately 0.37 ns, in good agreement with 0.38 ns [unk] <tau(r)> [unk] 0.41 ns, previously determined from (13)C and (15)N spin-lattice relaxation data.


An inductively powered telemetry system for temperature, EKG, and activity monitoring. An implant telemetry system for the simultaneous monitoring of temperature, activity, and EKG from small animals, such as rats, has recently been designed with the novel feature that instead of a battery the system is energized by an inductive field. A 250 kHz resonant coil surrounds the cage (30 X 30 X 20 cm) and provides the approximately 100 muW of power required to operate the implant transmitter while allowing the animal unrestrained movement in the cage. The implant can also be battery operated if desired RF transmission is in the 8-10 MHz band, which allows the use of a simple, essentially single IC chip, receiver.


Discrete membrane surface charge distributions. Effect of fluctuations near individual channels. Each gating mechanism controlling permeability in a membrane may be influenced by only a few charge binding sites on the membrane surface, so that fluctuations in the occupancy of these sites are important. Tow extreme cases arise. (a) The time scale of these fluctuations is much shorter than the gating time constant. Then the gating mechanisms are subject to a rapidly varying electric field. If the gating in the absence of these fluctuations obeys exponential kinetics, so does the gating in the presence of the fluctuations. Changes in surface charge do not simply shift the gating variable curves on the voltage axis, but also change their shape. Such effects are seen experimentally and cannot be explained in terms of conventional surface charge theory. If the activation curve in the absence of any surface charge binding is symmetric about the half-activation point, when some of the surface charge sites are occupied the activation curve is in general asymmetric. (b) The fluctuations occur much more slowly than the gating reaction. There are several pools of channels present with different time constant and activation curves. Again the activation curve is asymmetric about the half-activation point, and its shape is changed by alterations in the surface charge. The kinetics of gating of the whole population of channels are multiexponential.


Activity monitoring in chronic illness: time out of bed for tetraplegics during comprehensive rehabilitation. Unobtrusive longitudinal monitoring of what patients actually do during comprehensive rehabilitation represents a relatively unexplored but potentially very useful approach to functional evaluation. Recent advances in biomedical technology have created the possibility of supplementing and/or substituting a number of human observations with instrument-based measurements. This paper presents the first data obtained as part of a systematic research effort to explore the feasibility and utility of applying unobtrusive instrumentation to monitor selected patient activities over extended periods of time. The target activity studied was time out of bed for 36 spinal cord injury patients undergoing comprehensive rehabilitation. Measurements were made with a Rest Time Monitor (RTM) which provides a continuous, objective record of when a patient is out of bed, how often and for how long. Based on this experience, a 'standard' activity curve has been developed which is used as a reference in assessing the weekly progress of individual patients. Distinctive types of activity patterns are described in relation to how patients do clinically, and functionally during hospitalization and 12 months after discharge. In addition, data are presented which compare in-hospital activity patterns by level of injury, age and presence or absence of complications. This initial study suggests that longitudinal activity monitoring is a useful tool for clinical assessment and management and may help predict those patients who are most likely to develop pre- and postdischarge complications.


Telemetry of intracranial pressure.

Telemetry of intracranial pressure. In the care of patients with abnormal intracranial pressure, it is important to continuously and accurately measure the intracranial pressure so that treatment can be instituted. Strain gage pressure cells have successfully replaced the open-end manometer for chronic use but have lacked the stability for accurate long-term measurements. The system described uses a capacitive pressure transducer with excellent long-term stability. The transducer, electronics, and transmitter package can be implanted to telemeter the pressure transcutaneously, reducing the danger of infection by the elimination of transcutaneous leads. The pressure modulates the frequency of an oscillator in the 8-10 MHz region and provides an easily telemetered signal. To eliminate the problems of periodic battery replacement, the system is energized inductively by a coil placed externally over the implant device, so that the operating life is virtually unlimited.


Bioconcentration ratio of diazinon by freshwater fish and snail. The bioconcentration ratios of diazinon from water by freshwater fishes were generally larger than that of crayfish and snails. Among fishes, the bioconcentration ratio of diazinon by topmouth gudgeon was the highest value, 152 being average. However, elimination of diazinon from fish body was linearly rapid. The influence of test concentration centration ratio of diazinon in whole body of topmouth gudgeon was increased proportional to the body weight.


Lead and cadmium in hair as an indicator of body burden in rats of different age. The purpose of this work was to evaluate whether hair values of lead and cadmium can be used as an indicator of the body burden of these metals in different age groups. The experiments were performed on rats aged 2 and 18 weeks, which received 203Pb and 115mCd by intraperitoneal injection. The whole body retention and the retention of these radioisotopes in the hair (including the skin) was determined 7 days later. Younger animals showed a higher retention in the whole body and hair of radioactive lead and cadmium. The hair values when expressed as the percentage of the whole body retention were for 203Pb the same in young and adult rats but for 115mCd they were 2 to 3 times higher in young animals than in adults. It is concluded that lead hair values are a good indicator of the total body burden in both age groups. However, the cadmium body burden of young animals would be greatly overestimated if based on hair values only. This findings might be relevant for interpreting results of hair concentrations of lead and cadmium in children.


Effect of hexachlorobenzene (HCB) on photosynthetic oxygen evolution and respiration of Chlorella pyrenoidosa. In experiments with Chlorella pyrenoidosa it was shown that an exposure of these cells to HCB at a dose level of 0.1, 1.0, and 5.0 ppm caused an inhibition of photosynthetic oxygen evolution of 33.3, 42, and 51%, respectively. Respiration, however, was inhibited only slightly, if at all.


Histopathology and histochemistry of insects treated with chemosterilants. VII. On the corpora cardiaca of Periplaneta americana (L) treated with hempa. The neurosecretory granules are reduced and intrinsic cells are damaged in the corpora cardiaca of the last instar nymphs of P. americana treated with hempa.


Mercury content in museum and recent specimens of chiroptera in Japan. The mercury content of insectivorous Chiroptera caught in 1890, when mercurial pesticides had not yet been in use, and preserved in a museum in alcohol were compared with those caught in 1965--1967 or 1970--1975, during and after the use of mercurial pesticides, and kept frozen. The mercury content of the Chiroptera caught in 1890 was lower than that of those caught during or after the use of mercurial pesticides. Difference in mercury content between bats caught during and after use was not significant.


Persistence of fungicide Euparen on strawberry and/or in some canned products of strawberry. There was studied the persistence of Euparen(dichlofluanid) on strawberry and in some canned products of strawberry, respectively. The rate of decrease of dichlofluanid residues on the leaves of strawberry is proceeding according to the first-order reaction kinetics in the initial 21 days. The content of dichlofluanid residues on strawberry treated twice with fungicide varies from 0.5 to 1.0 ppm, for strawberry sprayed three times from 1.0 to 2.0 ppm, respectively. The significant decay of dichlofluanid residues occurs during the technological procedures applied. The sensoric analysis of strawberry has proved the negative influence of the third spray of fungicide in the initial days. No significance differences between strawberry treated with fungicide and control has been found in flavor and taste of the canned products investigated.


Paranoid states.

Paranoid states. Paranoid states is a term that covers a number of different disorders in which persecutory and grandiose ideas and delusions constitute a significant part of the symptoms. The most important are those conditions that are now generally accepted as being members of the group of schizophrenias. These symptoms become more important in conditions of social isolation and sensory deprivation. They appear in some organic cerebral conditions and may colour any breakdown that develops in some types of personality.


A pilot study on the use of visual field expanders. The nature and magnitude of the visual difficulties of five volunteer patients with severely contracted visual field and high visual acuities was investigated by several techniques. These comprised a questionnaire providing a quantitative score of visual impairment, a specially devised visual search task, and an arbitrary method of estimating visual efficiency. Many aspects of visual impairment resulting from contract visual fields were revealed and discussed. Performance scores on the search task indicated that the field expander would probably be useful to a small number of cases for continuous wear, usually as a binocular bioptic system. Other cases might benefit from a clip-on or hand-held device for occasional use. Methods of manufacture and dispensing and difficulty in locating suitable patients were the major limiting factors in this study. The methods of assessment, and the optical system described in this study are worthy of further investigation and development for trial on a larger number of patients.


Panum's area explained in terms of known acuity mechanism. Comparisons between the various types of binocular and monocular visual acuity thresholds are made in this study. The results obtained in monocular resolution and binocular diplopia experiments support LeGrand's view regarding Panum's area. Thus the physiological mechanism which appears to account for both monocular resolution and binocular diplopia thresholds could also account for a spatial tolerance which gives rise to Panum's area.


Resolution acuity in astigmats: evidence for a critical period in the human visual system. Astigmats, who have been fully optically corrected, show an acuity configuration highly characteristic of the uncorrected astigmatism when they are tested with gratings of different orientations. This phenomenon, which is called meridional amblyopia, has been supposed to be neural in origin. This paper attempts to show that there is evidence for a critical period in the visual system of humans. In the experiment described here twelve astigmatic subjects were tested against a control group of six non-astigmatic (emmetropic) subjects. The astigmatic subjects differed in the ages at which they had been initially optically corrected. Square-wave gratings were used to test the subjects and measures of acuity for different orientations were recorded. It was found that those astigmatic subjects corrected above the age of seven showed the usual acuity decrement while those corrected below seven showed significantly smaller meridional amblyopia. The age of seven, therefore, was taken to mark the end of a critical period in the development of the human visual system, after which the system ceases to be structurally influenced by visual input.


The refraction of the eye in the relation to spherical aberration and pupil size. Available theoretical and experimental data on the dependence of the subjective refraction of the eye on spherical aberration and pupil size are reviewed and additional experimental results are presented. Under photopic conditions, refraction varies little (similar to 0.3 DS) with pupil diameter, even when substantial amounts of spherical aberration are present (similar to 1.0 DS). It is argued that this result may be attributed to the insensitivity of optimal focus to spherical aberration at the spatial frequencies involved in photopic refraction, to the Stiles-Crawford effect and to the influence of aberrations other than primary spherical aberration in the outer zones of the pupil. The signficance of these findings is indicated in relation to possible discrepancies between the results of objective and subjective refractions when large pupils are in use.


The effect of exposure time upon perceived size. An experiment whereby a standard filled circle is exposed for 100-1000 msec on the tachistoscope for ten subjects. Each is asked to choose a comparison circle, which appears to be the same size, out of a series of eleven filled circles of various angular subtenses larger and smaller than the standard filled circle in the tachistoscope. The results indicate that exposure time has a role in the perception of size.


The effectiveness of a service for helping destitute men. The effectiveness of a voluntary organization which aimed to help destitute men contacted by means of a 'soup run' was evaluated. The assessment was carried out in stages. At the end of each stage results were discussed with the organization and a set of recommendations for further action put forward. At the end of the first stage, it was agreed that the organization's aim should be restricted to attempting to help men settle in one of its houses (staffed by young volunteer workers) for a period of at least three months. A number of recommendations intended to achieve this result were unsuccessful. Following the setting up of a night shelter, it was observed that many men attended regularly. An assessment procedure was instituted which resulted in the selection of men who did settle in the houses for long periods, so much so that no further admissions became possible.


The prevalence of problem drinking and alcoholism in the West of Scotland. A 10 per cent probability sample of the population of Clydebank was interviewed, using an indirect questionnaire, to assess the extent of alcohol-related disabilities. Eighty-two per cent of 4,397 persons gave information and weighted symptom-scoring analysis showed 5.0 per cent of adult males and 1.1 per cent of adult females could be classified as problem drinkers and 5.2 per cent and 0.5 per cent respectively could be labelled alcoholics. These figures are compared to existing Scottish and English alcoholism prevalence statistics.


Stresses upon the relatives of head-injured patients. As part of a prospective study of closed head injury, 54 relatives were interviewed within a month of the patient's accident and again six and twelve months later. The degree of stress on the relatives was measured by means of the Wakefield Depression Scale and by interview questions. The worst period of stress for the majority of relatives appeared to be during the first month after the accident. However, the degree of stress appeared to level off by the sixth month and no further diminution was found at twelve months. Stress was apparently mediated by the relatives' perception of personality changes and subjective defects. It was not affected by the severity of the head injury or associated disabilities, nor by whether the patient had resumed work and leisure activities. The nature of the stress is analysed and methods of alleviating it discussed.


Actual practice of ECT in a health region of Britain. A field study of 14 treatment centres found broad agreement between clinical practice and the Royal College of Psychiatrists' Memorandum on the use of ECT. Differences in electrode placement and anaesthetic agents and a poor standard of safety and reliability in the electrical equipment was noted.


Recovery from ECT in elderly patients.

Recovery from ECT in elderly patients. Nine elderly depressed patients were given ECT in courses which alternated unilateral and bilateral electrode placement; recovery times were measured. When compared with similar times for younger patients, recovery took on average five times as long from unilateral treatment and nine times as long from bilateral. Within the group, bilateral treatment took significantly longer for recovery than unilateral treatment and was significantly more sensitive to cumulative effect and interval effect.


Violence and mental illness in a peasant society: characteristics of violent behaviours and 'Folk' use of restraints. Thirty-five people labelled as baa (crazy or insane) were studied in Laos--a  country without psychiatrists or psychiatric institutions. Informant information was obtained for violence prior to becoming baa, violence during the course of their baa condition, and violence during the seven days prior to interview. Observation for violence was made for a one day period at the time of the interview. Use of restraints was also assessed. Subjects were significantly more apt to have assaulted others, posed a risk to themselves, and been restrained (although not incarcerated) during their baa condition as compared to their previous state. Those in early stages of their condition (two years or less) manifested more violence than those later in their condition. 'Folk' use of restraints was applied only after dangerous or violent behaviour had occurred. Restraints were released as soon as practicable, but there was an 'ascending' use of certain restraint measures if violence persisted.


Undetermined deaths-suicide or accident? A consecutive series of 110 undertermined deaths (U.D.) was compared with matched samples of suicides and accidents recorded in the same metropolitan Coroner's District. The hypothesis tested was that U.D. are mostly concealed suicides and will resemble known suicides more closely than accidents. The samples were compared on social and demographic variables, psychiatric and physical illness, evidence of suicide intent, information available to the Coroner and the circumstances of death. The results did not confirm the hypothesis. The study widens the investigation of the mortality of mental disorder from unnatural causes beyond the category of suicide.


Humans and pets and attachment.

Humans and pets and attachment. The bond between human and pet depends on their commonality as animals and their mutual need for attachment. Under abnormal circumstances of developmental frustration a human may displace an overdetermined need for attachment to the pet. The attachment relationship is pathological because of its defensive purpose, and its interruption can create enduring psychiatric reactions. The paper details the developmental determinants for this interaction.


Lithium treatment of chronic cluster headaches. On the basis of reports of reduced MAO activity in migraine and cluster headaches and on a report that lithium carbonate activates MAO, the authors administered lithium carbonate to two patients whose cluster headaches had brought them to the point of contemplating suicide. Both patients responded quite dramatically. Case 1 has now been virtually free of headaches for over two years and Case 2 has been in remission for over twelve months.


Obstructive jaundice and portal vein calcification. Two patients with extrahepatic portal vein obstruction are described in whom calcification within the thrombus was identified during investigation for obstructive jaundice. Evidence from percutaneous cholangiography in one, and endoscopic cannulation of the common bile duct in the other, supported the view that the common bile duct was being partially compressed by the calcified cavernoma.


Is pancreatogram interpretation reliable?--a study of observer variation and error. Observer variation in the interpretation of endoscopic pancreatograms has been examined by asking four experienced observers to assess 40 sets of well-documented radiographs (from 20 patients with cancer and 20 with pancreatitis), both without ("blind") and with clinical details, each on three occasions. Individual consistency for "blind" diagnoses ranged from 61% to 78%, increasing significantly with clinical information. Overall diagnostic accuracy with clinical information varied from 52% to 83% for cancer, and from 87% to 95% for pancreatitis. However, unanimous and correct opinions were given by the four observers for only 53% of all cases, even when clinical details were provided. Clinical information changed the radiographic diagnosis in 43% of assessments, 83% of these changes leading to improved accuracy. ERCP gives direct information about the major pancreatic and biliary duct systems and often provides an accurate diagnosis. Caution must be exercised in relying upon radiological appearances alone.


Lateral subluxation of the atlas in rheumatoid arthritis. Two patients with lateral subluxation of the atlas resulting from rheumatoid disease involving the upper cervical spine have been described. The deformity can be suspected on clinical grounds and in one of our two patients spinal cord damage was a sequel. Erosion of the opposing surfaces of the odontoid and lateral masses of the atlas with detachment of the transverse ligament and deeper fibres of the posterior longitudinal ligament appear to underlie this deformity. Radiological confirmation may require AP views with the head tilted to one or other side.


A comparison of grey-scale image recording systems. There is currently a rapid rise in the variety of image recording systems and recording media available for use with ultrasound and CT scanners. We have evaluated nine different systems and ten recording media and have compared their cost, convenience and performance. The choice of system in a particular department depends upon many factors, especially the number of images recorded and the reasons for recording them. We suggest that a busy department will probably require one of the more expensive automatic devices since these are the most convenient to use and have the lowest cost per image.


Reduction of radiation dose to patients in xeroradiography. A method for reducing the radiation dose received by the patient in xeroradiography is described. It is shown, theoretically, that a dose reduction of about 50% can be achieved, and measurements of skin exposure confirm reductions of this order. There is no appreciable loss of image quality, and the theory suggests that it may even be possible to enhance the visualization of soft tissue by this method.


The influence of size and radiopharmaceutical concentration ratio on the detection of abnormalities in clinical radionuclide imaging. The effect of the size of an abnormality on its detectability was measured. The cylindrical abnormalities studied, with diameters ranging from 3 mm to 4 cm, were superimposed on a uniform background. To avoid artefacts produced by the imaging devices, the images were simulated by computer. The method of constant stimulus was used to determine the detectability of the abnormalities. By using a Perspex phantom filled with 99Tcm, measurements were made of the concentration ratio between abnormality and background which permitted detection of the abnormality. This allowed evaluation of the effectiveness of 99Tcm pertechnetate in the detection of small abnormalities. Assuming a concentration ratio between abnormal and normal tissue of 22.5:1, then at a depth of 50 mm in the brain a cylindrical abnormality of about 8 mm diameter was the smallest detectable under the chosen scanning conditions.


The effect of chronic reductions in the arterial partial pressure of oxygen on the radiation response of an experimental tumour. A previous study by the same authors has reported the effect of acute reductions in the arterial partial pressure of oxygen (PaO2) on tumour response to radiation. The results have been extended in the present paper to investigate tumour response to radiation in animals in which the PaO2 is chronically reduced. The purpose of these experiments was to simulate the condition of cancer patients undergoing radiotherapy in the presence of chronically low PaO2 values as might be expected in patients with chronic respiratory disease. Mice bearing transplantable KHT sarcomas were kept in a 12% O2 environment prior to (10--16 days), during and following the radiation treatment of their tumours. During the period of low PaO2 (about 50 mm Hg) exposure, the mice were found to increase their haemoglobin (Hg) levels by approximately 50%. Because of this increase, the response, determined using a growth delay assay of the tumours irradiated at reduced PaO2 was found to be the same as that observed for tumours in mice breathing air throughout the experiment. In mice with reduced PaO2 levels maintained at normal Hb concentrations by periodic bleeding, tumour response was found to be similar to that of mice with acute PaO2 reductions. These results indicate that chronic PaO2 reductions in the absence of Hb compensation may have a detrimental effect on the success of a radiation treatment.


The effect of vascular occlusion on the thermal sensitization of a mouse tumour. The effect of occluding the blood supply to a mouse tumour (with a metal clamp) has been studied for both irradiation and heating. Local heat was applied by immersion in a water bath for one hour at 42.8 degrees C or for 15 minutes at 44.8 degrees C. Occlusion of the blood supply during heating has a profound cytotoxic effect on the tumour, even in the absence of irradiation. Most tumours treated with 42.8 degrees C for one hour under clamped conditions were locally controlled whether they were irradiated or not. Tumours heated with their blood supply unobstructed showed a lesser sensitivity to heat, seen as an increased sensitivity to X rays with a thermal enhancement ratio of 1.8--2.6. With the shorter period of more intense heat (44.8 degrees C for 15 min), the effect of increasing the clamping time before heating was studied. The proportion of tumours locally controlled increased from 33% if the clamp was applied immediately before heating to 83% if the clamp was present for 60 minutes before heating commenced. No cures were observed for heat applied immediately before clamping, or immediately after release of the clamp. Accumulation of metabolic products or pH changes are implicated as the factors which alter the thermal sensitivity of these tumour cells.


Relief of lymph obstruction by use of a bridge of mesentery and ileum. The background to the use of a bridge of ileum with its associated mesentery in the relief of lymphatic obstruction is described. A case report of the successful use of this method in a 22-year-old patient with lymphoedema praecox is presented. Following experience with further cases, it is suggested that, provided changes in the lymph channels and in the tissues of the affected limb are not irreversibly damaged, effective drainage through small gut lymphatics may be achieved.


Management of abdominal aortic aneurysm. A series of 245 patients was operated upon for abdominal aortic aneurysm during the years 1969-77, of whom 162 were elective cases while in 83 the aneurysm was leaking or had ruptured. The hospital mortality for the latter group fell from 77 per cent at the beginning of the study period to 30 per cent at the end. For elective operations, hospital mortality averaged 9.3 per cent, though during the last 2 years there were no deaths in the 51 consecutive cases. Operative methods and postoperative treatment changed during the years of the study, with few excision-replacement grafts and greater use of the inlay technique, most of the latter being simple unbranched Dacron tubes. Early graft infection, the most important and serious surgical complication, caused 9 deaths, an overall incidence of 3.7 per cent, of which 8 were in patients who received no perioperative antibiotics and only 1 among the patients who did receive them. All deaths were in the inlay group. The reasons for this are discussed. Since July 1976 perioperative antibiotic treatment has been routine for all arterial prosthetic graft patients in our hospital.


Ruptured abdominal aortic aneurysms.

Ruptured abdominal aortic aneurysms. The results of operation in 76 patients with a ruptured abdominal aortic aneurysm are presented with an analysis of the cause of operative death. Overall mortality was 58 per cent and preoperative hypotension significantly increased mortality; deterioration while awaiting operation made a successful outcome particularly unlikely. No group could be identified, however, in which operation was without hope of saving life, and age alone should not contraindicate surgery.


Lumbar radiculopathy contralateral to upper lumbar disc herniation: report of 3 cases. Three cases of lumbar radiculopathy contralateral to an upper lumbar disc herniation are reported. This clinical syndrome is explained on the basis of prominent spondylotic changes and stenosis contralateral to the side of disc herniation associated with anatomical anomalies of lumbar nerve roots. The disc herniation causes displacement and impaction of the dural sac with the emerging nerve roots in a narrowed lateral recess.


A review of 158 gunshot wounds to the chest. One hundred and fifty-eight gunshot wounds to the chest treated at the Royal Victoria Hospital, Belfast, between August 1969 and July 1976 are reviewed. The place of open operation in the treatment is discussed.


Cholecystectomy and a simple technique of operative cholangiography. A simple, easily reproducible technique of operative cholangiography is described. The technique has three advantages: (a) there is no need to divide or ligate the cystic duct; (b) it demonstrates the cystic duct anatomy clearly and is particularly useful in demonstrating stones in that duct thus eliminating the hazard of the retained stone in the cystic duct stump; (c) it is possible to eliminate the problem of false positives due to air bubbles. A consecutive series of 442 cholecystectomy patients is reviewed. The overall operative mortality was 1.6 per cent; no death could be attributed to operative cholangiography. Thirty-five of 324 patients (10.8 per cent) with gallstones and no history of jaundice were shown to have unexpected abnormalities in the common bile duct.