bluuebunny/crossref_metadata_2025_split huggingface dataset:
Homeostatic control of the excitation–inhibition balance in cortical layer 5 pyramidal neurons
Authors: Le Roux Nicolas , Amar Muriel , Baux Gérard , Fossier Philippe 
Published: December 2006

AbstractHomeostatic regulation in the brain is thought to be achieved through a control of the synaptic strength by close interactions between excitation and inhibition in cortical circuits. We recorded in a layer 5 pyramidal neuron of rat cortex the composite response to an electrical stimulation of various layers (2–3, 4 or 6). Decomposition of the global conductance change in its excitatory and inhibitory components permits a direct measurement of excitation–inhibition (E‐I) balance. Whatever the stimulated layer was, afferent inputs led to a conductance change consisting of 20% excitation and 80% inhibition. Changing synaptic strengths in cortical networks by using a high‐frequency of stimulation (HFS) protocol or a low‐frequency of stimulation (LFS) protocol (classically used to induce long‐term potentiation or long‐term depression at the synaptic level) were checked in order to disrupt this balance. Application of HFS protocols in layers 2–3, 4 or 6, or of LFS protocols in layer 4 induced, respectively, long‐term paralleled increases or long‐term paralleled decreases in E and I which did not change the E‐I balance. LFS protocols in layers 2–3 or 6 decreased E but not I and disrupted the balance. It is proposed that regulatory mechanisms might be mainly sustained by recurrent connectivity between excitatory and inhibitory neuronal circuits and by modulation of shunting GABAA inhibition in the layer 5 pyramidal neuron.
Estradiol stimulates progenitor cell division in the ventricular and subventricular zones of the embryonic neocortex
Authors: Martínez‐Cerdeño Verónica , Noctor Stephen C. , Kriegstein Arnold R. 
Published: December 2006

AbstractTwo distinct populations of cerebral cortical progenitor cells that generate neurons during embryogenesis have been identified: radial glial cells and intermediate progenitor cells. Despite advances in our understanding of progenitor cell populations, we know relatively little about factors that regulate their proliferative behaviour. 17‐β‐Estradiol (E2) is present in the adult and developing mammalian brain, and plays an important role in central nervous system processes such as neuronal differentiation, survival and plasticity. E2 also stimulates neurogenesis in the adult dentate gyrus. We examined the role of E2 during embryonic cortical neurogenesis through immunohistochemistry, in situ hybridization, functional enzyme assay, organotypic culture and in utero administration of estradiol‐blocking agents in mice. We show that aromatase, the E2 synthesizing enzyme, is present in the embryonic neocortex, that estrogen receptor‐α is present in progenitor cells during cortical neurogenesis, that in vitro E2 administration rapidly promotes proliferation, and that in utero blockade of estrogen receptors decreases proliferation of embryonic cortical progenitor cells. Furthermore, the E2 inhibitor α‐fetoprotein is expressed at high levels by radial glial cells but at lower levels by intermediate progenitor cells, suggesting that E2 differentially influences the proliferation of these cortical progenitor cell types. These findings demonstrate a new functional role for E2 as a proliferative agent during critical stages of cerebral cortex development.
Use of the ASA Physical Status Grading System in pediatric practice
Authors: APLIN STEPHANIE , BAINES DAVID , DE LIMA JONATHAN 
Published: December 2006

SummaryBackground:  The American Society of Anesthesiologists (ASA) Grading System is widely used to describe preoperative physical status. Inconsistency of grading between anesthetists has been demonstrated in studies using hypothetical adult patient scenarios. We aimed to investigate the use and interrater reliability of the ASA Grading System in pediatric anesthesia practice.Methods:  A two‐part questionnaire was mailed to all 176 current members of the Society of Paediatric Anaesthesia in New Zealand and Australia (SPANZA). The first part of the questionnaire obtained information regarding type of practice, use of the ASA Grading System, opinions regarding grading systems in general and opinions as to the limitations of the ASA System. In Part II, respondents were presented with 15 hypothetical patient scenarios and asked to grade them using the ASA System. The scenarios were designed to cover a range of ages and conditions common in pediatric practice.Results:  There were 130 replies (73.9%) after two mailings. The majority of respondents had been in predominantly pediatric practice for >5 years, had read the ASA Grading System within the last 2 years, and used it regularly. However, 30% modified the grading system for use in pediatrics.Many limitations of the ASA System in pediatric practice were identified. There was considerable lack of consistency in the grading of the hypothetical patient scenarios, with each scenario receiving at least three different ASA gradings. Case scenarios involving trauma or airway compromise were associated with greater inconsistency. There was no demonstrable correlation between grading consistency and patient age, familiarity with the ASA Grading System or experience of the anesthetist.Conclusions:  The ASA Grading System shows poor interrater reliability in pediatric practice, as it does in adults. This should be borne in mind when using the ASA System for clinical or scientific work in pediatrics. A physical status grading system developed specifically for use in pediatrics may reduce inconsistency.
Persistent symptoms of functional outlet obstruction after rectocele repair
Authors: Puigdollers A. , Fernández‐Fraga X. , Azpiroz F. 
Published: December 2006

AbstractBackground  Rectocele is frequently associated with constipation, but it is not known whether a causal relationship exists.Objective  To determine the effect of rectocele repair on symptoms of constipation.Method  Thirty‐five women (28–79 years) consecutively operated for rectocele repair (11 transanal approach and 24 transperineal) were included in the prospective study. Using a structured questionnaire, the following criteria for constipation were evaluated: (a) straining, (b) sensation of anal blockage, (c) sensation of incomplete evacuation, (d) manual manoeuvres to facilitate defecation, (e) stool consistency and (f) stool frequency. The evaluation was performed before and 1 year after rectocele repair.Results  Before the operation all patients had two or more constipation criteria, including sensation of anal blockage. One year after the operation, the incidence of all symptoms significantly improved (from 3.9 ± 0.2 to 1.9 ± 0.3; P < 0.01). However, in 18 patients two or more criteria of constipation persisted, two patients presented one criterion, and only 15 patients became asymptomatic. Neither parity nor the type of surgical approach (endorectal vs transperineal) was related to the response to treatment. In eight patients who had a previous hysterectomy the result was significantly worse.Conclusion  In a considerable proportion of patients, constipation persists after rectocele repair, suggesting that these symptoms are related to an underlying dysfunction.
DEATH AND TRANSPLANTATION: LET’S TRY TO GET THINGS METHODOLOGICALLY STRAIGHT
Authors: BONIOLO GIOVANNI 
Published: December 2006

ABSTRACTThe purpose of this paper is methodological. I begin by showing the methodological frailties of both the heart and brain approach to the criteria of death used in connection with organ transplantation. I then clarify what a definition is. Finally, I propose to abandon the definition of death, and suggest a pragmatic definition of ‘explantability window’.
INFORMED CONSENT AND THE MISATTRIBUTED PATERNITY PROBLEM IN GENETIC COUNSELING
Authors: LUCAST ERICA K. 
Published: December 2006

ABSTRACTWhen misattributed paternity is discovered in the course of genetic testing, a genetic counselor is presented with a dilemma concerning whether to reveal this information to the clients. She is committed to treating the clients equally and enabling informed decision making, but disclosing the information may carry consequences for the woman that the counselor cannot judge in advance. A frequent suggestion aimed at avoiding this problem is to include the risk of discovering nonpaternity in the informed consent process for counseling. In this paper I argue that such a move does not resolve the problem, because the conflict hinges on the interpretation of equality on which the counselor operates. Given the principles of genetic counseling, neither construal of equality yields a satisfactory solution to the conflict. In fact, I conclude that including nonpaternity in informed consent is not endorsed by either view, and we are still left with the question of what to do should nonpaternity be discovered. I suggest a compromise position concerning disclosure, involving revealing relevant genetic information but withholding nonpaternity when possible.
INVESTIGATIONS INTO MECHANISMS RESPONSIBLE FOR SEIZURES INDUCED BY CHLORINATED HYDROCARBON INSECTICIDES: THE ROLE OF BRAIN AMMONIA AND GLUTAMINE IN CONVULSIONS IN THE RAT AND COCKEREL1
Authors: Omer V. St. 
Published: December 2006

Abstract— Seizures were produced in adult female rats and in cockerels (Gallus domesticusL.) after the intracarotid administration of four structurally‐unrelated chlorinated hydrocarbon insecticides. The temporal relationship of the course of the convulsions to levels in whole brain of ammonia and glutamine was examined. High levels of brain ammonia occurred in rats and cockerels poisoned acutely with lindane, dieldrin, heptachlor and DDT. The intensity of convulsions and other neurological signs coincided with and were directly correlated with the increases in brain ammonia, whereas interictal periods were associated with decreased levels of ammonia. In both species the order of drug toxicity was lindane > dieldrin > heptachlor > DDT.Significantly elevated levels of brain glutamine were induced in the cockerels after administration of all four insecticides. In contrast, increased levels of glutamine in rats were found only in those intoxicated with lindane and dieldrin. Although the ammonia‐binding mechanism (conversion of free ammonia into glutamine) was saturated throughout the experiments in both the rats and cockerels, the latter were more resistant to ammonia toxicity by virtue of being able to convert free ammonia into glutamine more efficiently than rats. These data, together with data reported by others, lead to the conclusion that the four structurally‐unrelated chlorinated hydrocarbon insecticides probably induced convulsions in both species by a common mechanism, involving interference with the production and/or utilization of ammonia.
FREE AMINO ACIDS AND RELATED COMPOUNDS IN BIOPSIES OF HUMAN BRAIN
Authors: Perry T. L. , Hansen S. , Berry K. , Mok C. , Lesk D. 
Published: December 2006

Abstract— Contents (μmol/g wet wt.) of 35 free amino acids and related compounds were measured in biopsies of human brain from ten patients. Brain specimens were frozen in liquid nitrogen within 10 sec of their removal at neurosurgery; thus, the values found should approximate those which occur in living brain.Levels in free pools of biopsied cerebral cortex of most of the amino acids that are constituents of proteins were only 20‐50 per cent of those found in autopsied cortex. The content of cystine and ethanolamine was much lower in biopsied than in autopsied cortex. Concentrations of GABA in biopsied cortex were only 20 per cent as high as those found in autopsied cortex, and levels of γ‐aminobutyryl dipeptides were also significantly lower in biopsied cortex. Amounts of cystathionine in biopsied cortex varied markedly, but averaged much higher than in autopsied cortex; a single biopsy specimen of cerebellar grey matter had a cystathionine content 36‐fold greater than the mean found in autopsied cerebellum.Appreciable variability in contents among cortical biopsies was found for glycerophosphoethanolamine, phosphoethanolamine, ethanolamine, taurine, aspartic acid, glutamic acid, glutamine, and GABA, as well as for cystathionine. Whether this variability occurred between different subjects, or between different cortical areas, was not clear, although the former possibility was suggested by findings in multiple cortical biopsies from one patient.
POLYRIBOSOME DISAGGREGATION AND CELL‐FREE PROTEIN SYNTHESIS IN PREPARATIONS FROM CEREBRAL CORTEX OF HYPERPHENYLALANINEMIC RATS1
Authors: Siegel F. L. , Aoki K. , Colwell R. E. 
Published: December 2006

Abstract— Seven‐day‐old rats were injected intraperitoneally with l‐phenylalanine (1 g/kg) and the time course of brain polyribosome disaggregation and changes in brain levels of phenylalanine, tryptophan and tyrosine were determined. Disaggregation of brain polyribosomes preceded the increase in levels of phenylalanine in brain, and followed the same time course as depletion of tryptophan from brain.The effects of several metabolites of phenylalanine (which are formed in phenylketonuria) on protein synthesis in vitro was determined for brain and liver systems. None of the compounds tested was inhibitory at concentrations below 10 mM and in all cases hepatic protein synthesis was more sensitive to inhibition than was the corresponding system from brain.Ribosomal dimers, formed in brain after injection of phenylalanine, were incapable of supporting high levels of protein synthesis in vitro, a finding that suggested that the inhibition of protein synthesis in vitro in cell‐free systems of brain tissue after injection of phenylalanine into young rats was mediated by disaggregation of brain polyribosomes associated with tryptophan deficiency in brain.
FATTY ACIDS AND LONG CHAIN BASES OF VERTEBRATE BRAIN GANGLIOSIDES
Authors: Avrova N. F. , Zabelinskiï S. A. 
Published: December 2006

Abstract— Fatty acid and long‐chain base composition of gangliosides from brains of animals belonging to various vertebrate classes (fishes, amphibia, reptiles, birds and mammals) was studied by gas‐liquid chromatography. Stearic acid was found to be the main fatty acid everywhere. Brain gangliosides of cold‐blooded animals contain lesser amounts of stearic and higher amounts of palmitic and monoenoic acids as compared to those of mammals.Long‐chain bases were separated as trimethylsilyl derivatives. Large amounts (23‐48 per cent) of long chain bases with 20 carbon atoms were found in brain gangliosides of mammals while in those of cold‐blooded animals they constitute 3‐12 per cent of the total.The comparison of the composition of gangliosides with that of cerebrosides and sulphatides indicates, that the fatty acid and long chain base composition of gangliosides from mammalian brain differs from that of other glycosphingolipids, whereas in brains of cold‐blooded animals they are much more similar.
GLUTAMYL AND ASPARTYL MOIETIES OF CEREBRAL PROTEINS: ENRICHMENT IN MEMBRANE‐CONTAINING MICROSOMAL SUBFRACTIONS
Authors: Tower D. B. , Wherrett J. R. 
Published: December 2006

Abstract— The total mixed proteins (excluding proteolipids) were isolated from various tissues of the cat and from subcellular fractions of cat cerebral cortex and were compared for contents of total glutamyl and total aspartyl residues and total amide N. The proteins from renal cortex, testis and diaphragm were more acidic (proportionally more glutamyl and aspartyl residues with no increase of amide) than those from cerebral cortex, subcortical white matter and liver. Also the proteins isolated from cerebral cortical microsomes were more acidic than those from highly pure nuclear, mitochondrial and soluble subcellular fractions of cerebral cortex. Hepatic microsomal proteins gave very similar analyses.Subfractionation of the microsomal preparations from cerebral cortex and liver into deoxycholate‐insoluble (ribosomal) and deoxycholate‐soluble (‘membrane’) fractions localized the acidic proteins to the latter, ‘membrane’ subtraction. The ribosomal proteins isolated from cerebral cortex (and liver) had an amino acid composition very similar to that reported previously for ribosomal proteins in a number of tissues from various species. Upon column chromatography on DEAE‐celluIose, the deoxycholate‐soluble (‘membrane’) subtraction of hepatic microsomes yielded a peak (eluted with 0‐2 M‐phosphate, pH 5‐6, plus 0‐5 M‐NaCl) that contained an exceptionally high proportion (30 per cent) of glutamyl and aspartyl residues. We suggest that such acidic proteins may be characteristic of membranes and may subserve important metabolic functions therein.
PHOSPHOLIPID METABOLISM IN LIGHT AND DARK ADAPTED EXCISED RETINA
Authors: Urban P. F. , Dreyfus H. , Neskovic N. , Mandel P. 
Published: December 2006

Abstract— The phospholipid composition of, and the incorporation of labelled phosphorus into the different phospholipids of rat and calf retina have been studied. The influence of various conditions, such as dark and light adaptation, during the preparation of retina, lipid extraction and incubation of retina with radioactive phosphorus was investigated.The phospholipid composition of rat retina did not differ significantly from that of calf retina and the different conditions of preparation and incubation did not modify the distributions.The specific radioactivities of the different phospholipids of calf and rat retina, incubated in the presence of 32P, distinguished in both species two groups of components characterized by the rate of labelling. Phosphatidic acid (PA) and inositol glycerophospholipids (PI) belonged to the first group and showed the highest uptake of labelled phosphorus; the second group, comprising choline glycerophospholipids (PC), serine glycerophospholipids (PS), sphingomyelin (SP), ethanolamine glycerophospholipids (PE) and cardiolipin (CL) showed low incorporation activities. Only SP was labelled differently in rat and calf retina. With the exception of PS, there was no evidence for the influence of light on the turnover of individual phospholipids. The finding that PS showed higher specific radioactivities when adaptation and incubation proceeded in the dark, seems to be of interest and needs further study.
HIGH AFFINITY UPTAKE OF TRANSMITTERS: STUDIES ON THE UPTAKE OF l‐ASPARTATE, GABA, l‐GLUTAMATE AND GLYCINE IN CAT SPINAL CORD
Authors: Balcar V. J. , Johnston G. A. R. 
Published: December 2006

Abstract— The uptake of l‐aspartate, l‐glutamate and glycine each appeared to be mediated by two kinetically distinct systems with apparent Km's of the order of 10 ('high affinity') and 100 μM ('low affinity') in slices of cat spinal cord, whereas the uptake of GABA appeared to be mediated by a single system of high affinity. The high affinity uptake of these amino acids in slices of spinal grey matter was approximately 5 times faster than that in slices of spinal white matter. The high affinity uptake systems in the cord slices survived homogenisation of the tissue under conditions known to preserve nerve terminals. Subcellular fractionation studies indicated that osmotically‐sensitive particles of equilibrium density equivalent to that of 1.0 m‐sucrose were at least in part responsible for the uptake of these amino acids.Inhibition studies indicated that three structurally specific systems of high affinity transported these amino acids:

specific for glycine—not inhibited by GABA or any of the other depressant amino acids found in cat spinal cord;
specific for GABA—not inhibited by glycine, taurine, l‐aspartate or l‐glutamate and (3) specific for l‐aspartate and l‐glutamate—not inhibited by glycine or GABA but strongly inhibited by various acidic amino acids such as l‐cysteate and l‐cysteine sulphinate.

The high affinity uptake of these amino acids was not inhibited by any of the known antagonists of the postsynaptic actions of these amino acids—strychnine (glycine), bicuculline and benzyl penicillin (GABA), methioninesulphoximine and l‐glutamate diethyl ester (l‐aspartate and l‐glutamate). p‐Chloromercuriphenylsulphonate strongly inhibited the high affinity uptake of glycine and GABA but was much less effective as an inhibitor of l‐aspartate/l‐glutamate high affinity uptake. This is in good agreement with microelectrophoretic studies in which this mercurial was found to potentiate depression of neuronal firing induced by glycine and GABA much more readily than excitation induced by l‐aspartate or l‐glutamate. These findings suggest the importance of high affinity transport processes in the removal of amino acids from the synaptic environment.
INHIBITION BY APOMORPHINE OF DOPAMINE DEAMINATION IN THE RAT BRAIN
Authors: Chiara G. Di , Balakleevsky A. , Porceddu M. L. , Tagliamonte A. , Gessa G. L. 
Published: December 2006

Abstract— Apomorphine (A) inhibited dopamine deamination by rat brain mitochondria, but did not influence catechol‐O‐methyltransferase (COMT) activity by brain homogenates. The administration of apomorphine (10mg/kg i.p.) to normal rats increased brain dopamine (DA) by 34 per cent and decreased homovanillic acid (HVA) and dihydroxyphenylacetic acid (DOPAC) by 60 per cent. In rats treated with reserpine 15 min prior to A, the latter prevented the rise of cerebral HVA and DOPAC and the depletion of DA produced by the former. Finally, A decreased the L‐DOPA‐induced accumulation of HVA and DOPAC in the rat basal ganglia. These results indicate that A inhibits DA deamination by monoamine oxidase.This inhibition seems to be specific since apomorphine did not influence 5‐HIAA levels in normal rats and prevented neither central 5‐HT depletion nor 5‐HIAA rise induced by reserpine.
METABOLIC COMPARTMENTATION IN THE BRAIN: METABOLISM OF A TRICARBOXYLIC ACID CYCLE INTERMEDIATE, [1,4‐14C] SUCCINATE, AFTER INTRACEREBRAL ADMINISTRATION
Authors: Mouhler. H. , Patel A. J. , Balaazs R. 
Published: December 2006

Abstract— The metabolism of a tricarboxylic acid cycle (cycle) intermediate, [1.4‐'14C]succinate, was studied in the brain at 2 20 min after intracerebral injection. The oxidation of [14C]succinate was rapid, as shown by the incorporation of 14C into cycle amino acids which accounted for about 30 per cent and 70 per cent of the tissue ‐“Cat 2 and 10 min respectively. During the whole experimental period the specific radioactivity of glutamine was about three times higher than that of glutamate. Thus exogenous [14C]succinate elicited signs of metabolic compartmentation similar to those seen after the administration of short chain fatty acids or amino acids. A computer programme, based on data obtained previously on the metabolic compartmentation of acetate and of glucose in the brain, was used to simulate the kinetics of labelling of cycle amino acids after an input of [1.4‐14C]succinate. The correspondence of the simulated data with the experimental results was good in the first 10 min after injection, although the deviations were significant at later time points.Incorporation of 14C into GABA was very low (< 1 per cent of the amino acid ‐14C) after the injection of [1.4‐14C]succinate. Further, labelled GABA formation was not detected in the decapitated rat brain labelled in vivo with [1.4‐14C]succinate 2 min beforehand. Since the oxidation of [l,4‐14C]succinate via the cycle yields unlabellcd GABA. whereas the reversal of the reactions in the GABA bypath may introduce 14C from succinate into the GABA pool, the results indicate that this reversal is negligible even under the most favourable conditions, i.e. post mortem when both the NADH/NAD+ ratios and [14C]succinate concentrations arc high. The observations are therefore consistent with the view that glutamate is the predominant and probably the only source of GABA carbon in the brain both in vivo and post mortem.