bluuebunny/crossref_metadata_2025_split huggingface dataset:
Changes in Rabbit Brain Cytosolic and Membrane‐Bound Gangliosides During Prenatal Life
Authors: Sonnino Sandro , Ghidoni Riccardo , Masserini Massimo , Aporti Franco , Tettamanti Guido 
Published: October 2006

Abstract:The present study deals with the developmental profile of cytosolic and membrane‐bound gangliosides in rabbit whole brain from the 21st day of pregnancy, the time at which brain could be macroscopically recognized and handled, till birth. In this period of prenatal life the content of membrane‐bound gangliosides showed a 2.5‐fold increase, referred to fresh and dry brain weight and to membrane‐bound protein; the content of cytosolic gangliosides reached a maximum at 21‐22 days of pregnancy, and then underwent to birth a threefold diminution. The qualitative pattern of membrane‐bound gangliosides, in the same period of life, was characterized by an increase of GD1a and GM1 (more marked for GD1a), a decrease of GT1a, GT1b and GQ1b and a constant level of GD3 and GD1b. At 21 days of pregnancy the most abundant gangliosides were GT1b, and GQ1b, followed by GD1a and GD1b; at birth it was GD1a followed by GT1b GD1b, and GM1 The qualitative pattern of cytosolic gangliosides closely resembled, during the entire period of prenatal life examined, that of membrane‐bound gangliosides.
Distribution of Soluble Proteins Within Spinal Motoneurons: A Quantitative Two‐Dimensional Electrophoretic Analysis
Authors: Weil David E. , McIlwain D. L. 
Published: October 2006

Abstract:Soluble protein fractions obtained from bovine lumbar spinal motoneuron cell bodies, ventral gray matter, and ventral and dorsal roots were analyzed by two‐dimensional gel electrophoresis. Each extract was separated into Coomassie blue‐stained patterns of up to 350 polypeptides ranging in isoelectric point from pH 4 to 8 and in molecular weight from 10,000 to 200,000. Visual inspection of the protein pattern of the isolated cell bodies showed it to be substantially different from those of ventral gray matter and the spinal roots, while the patterns obtained from ventral and dorsal roots were indistinguishable. Computer‐assisted densitometry of the major soluble proteins from spinal roots showed no quantitative difference between the predominant proteins in ventral and dorsal root extracts. Differences of 10‐fold or more were common when the major proteins of the isolated perikarya were compared with those of the other fractions. Since most of the soluble proteins extracted from ventral and dorsal roots were probably derived from the axoplasm of motor and sensory nerves, respectively, these results are interpreted to mean that large differences exist in the distribution of individual soluble proteins between the cell body and axon of spinal motoneurons, while the major soluble proteins of spinal motor and sensory axons are highly similar.
Influence of Sodium‐Independent γ‐Aminobutyric Acid Binding on the Assay of Sodium‐Dependent γ‐Aminobutyric Acid Binding in a Membrane Preparation of Rat Brain
Authors: Kurioka Susumu , Matsuda Makoto 
Published: October 2006

Abstract:A large amount of [3H]GABA was bound to crude synaptic membrane fractions of rat. by sodium‐independent process in a medium that contained 100 μM [3H]GABA used for assaying GABA uptake site. This [3H]‐GABA binding was different from receptor binding of GABA. It was confirmed that this sodium‐independent [2H]GABA binding scarcely occurred in the presence of a physiological concentration of sodium chloride, and that sodium‐independent GABA binding had a negligible influence on sodium‐dependent GABA binding.
Inhibition by Methylmalonate of Glycine Uptake by Synaptosomes from Rat Spinal Cord
Authors: Lopez‐Lahoya J. , Garcia M. L. , Benavides J. , Ugarte M. 
Published: October 2006

Abstract:Methylmalonate is accumulated in the genetically linked deficiency of methylmalonyl‐CoA mutase (methylmalonic acidemia). In this condition is also observed an elevation of the glycine levels. This communication reports the inhibition of the synaptosomal glycine uptake by methylmalonate, when present at similar concentrations to those found in methylmalonic acidemia. This inhibition could be responsible, at least in part, for the neurological damage characteristic of this disease, by increasing the glycine levels in the synaptic cleft and thus interfering with the normal function of the inhibitory glycinergic synapsis in the spinal cord.
Endogenous Modulator of Benzodiazepine Binding in Rat Cortex
Authors: Chiu T. H. , Rosenberg H. C. 
Published: October 2006

Abstract:Benzodiazepine binding sites, solubilized with 1% digitonin, were used to study specific [3H]flunitrazepam ([3H]FNP) binding. Specific binding increased nonlinearly with increasing amounts of digitonin extract in the assay. Specific binding was increased, and the relationship to amount of extract became linear. in the presence of 2% polyethylene glycol 6000 (PEG). Heat treatment destroyed binding activity of the extract, but not ability to inhibit [3H]FNP binding. Kinetic analysis showed inhibition to be noncompetitive. The inhibitory activity was sensitive to trypsin. Extracts of repeatedly frozen, thawed, and washed membrane preparations still possessed inhibitory activity. It is suggested that digitonin solubilizes a membrane protein that inhibits benzodiazepine binding. PEG apparently removes this substance from the binding sites.
Identification of Neuron‐Specific Enolase and Nonneuronal Enolase in Human and Rat Brain on Two‐Dimensional Polyacrylamide Gels
Authors: Heydorn William E. , Creed G. Joseph , Marangos Paul J. , Jacobowitz David M. 
Published: October 2006

Abstract:The location of the enzymes neuron‐specific enolase and nonneuronal enolase on two‐dimensional gels generated from tissue samples obtained from fresh human and rat cortex has been identified. This identification is based upon the following criteria: (1) comigration on polyacrylamide gels with the appropriate purified protein and (2) staining on nitrocellulose protein blots of human and rat cortex using antibodies specific for each protein. The results show that our preparation of neuron‐specific enolase from rat and human brain is highly pure, as only one spot is obtained on two‐dimensional gels. Further, the antiserum to neuron‐specific enolase is highly specific, as it reacts only with neuron‐specific enolase on nitrocellulose blots derived from two‐dimensional gels of cortical tissue. The location of these proteins is of interest because it positively identifies two major brain proteins on two‐dimensional polyacrylamide gels of fresh cortical tissue. This information will be useful in a variety of future studies aimed at both identifying specific proteins on two‐dimensional gels and observing the effects of experimental manipulations on brain and other neuronal proteins.
Adenosine Inhibition of Histamine‐Stimulated Inositol Phospholipid Hydrolysis in Mouse Cerebral Cortex
Authors: Kendall D. A. , Hill S. J. 
Published: October 2006

AbstractThe effects of adenosine on inositol phospholipid hydrolysis in mouse cerebrocortical slices were examined. Despite having no effect alone, adenosine and some structural analogues inhibited histamine‐stimulated accumulation of inositol phosphates in a concentration‐dependent manner. The responses to carbachol, noradrenaline, 5‐hydroxytryptamine, and elevated KCl levels were unaffected. The effect of adenosine was on the maximal response to histamine rather than on its EC50. Several adenosine antagonists competitively blocked the inhibition due to adenosine. The results are discussed in relation to the previously reported enhancement of histamine‐stimulated hydrolysis of inositol phospholipids in guinea pig brain.
ADP‐Ribosylation with Pertussis Toxin Modulates the GTP‐Sensitive Opioid Ligand Binding in Digitonin‐Soluble Extracts of Rat Brain Membranes
Authors: Wong Yung H. , Demoliou‐Mason Catherine D. , Barnard Eric A. 
Published: October 2006

AbstractPertussis toxin‐catalyzed ADP‐ribosylation of the guanine nucleotide‐binding proteins Gi and Go is shown to proceed in Mg2+‐digitonin extracts from rat brain; the Mr 41,000 and Mr 39,000 peptides are labelled there as in the membranes. The ADP‐ribosylation in detergent solution retains the differential sensitivity to guanine nucleotide analogues. This reaction also removes the partial inhibition by the guanine nucleotides of the binding of opioid agonists, as does the same treatment in the membranes. The partial inhibition of agonist binding by Na+, however, is left unchanged. The binding of the antagonist naloxone is little affected by Na+ or by guanine nucleotides in the treated membranes, but the treated soluble receptors show an enhanced binding in high‐Na+ medium, although still guanine nucleotide insensitive. The data suggest that the toxin reaction in the absence of guanine nucleotides and agonist stabilizes the opioid receptor in a receptor‐G‐protein coupled state which is no longer sensitive to guanine nucleotides but retains its sensitivity to the Na+ ions.
Activation of Glutamate Dehydrogenase by Leucine and Its Nonmetabolizable Analogue in Rat Brain Synaptosomes
Authors: Erecińska Maria , Nelson David 
Published: October 2006

Abstract:Leucine and β‐(±)‐2‐aminobicyclo[2.2.1]heptane‐2‐carboxylic acid (BCH) stimulated, in a dose‐dependent manner, reductive amination of 2‐oxoglutarate in rat brain synaptosomes treated with Triton X‐100. The concentration dependence curves were sigmoid, with 10–15‐fold stimulations at 15 mM leucine (or BCH); oxidative deamination of glutamate also was enhanced, albeit less. In intact synaptosomes, leucine and BCH elevated oxygen uptake and increased ammonia formation, consistent with stimulation of glutamate dehydrogenase (GDH). Enhancement of oxidative deamination was seen with endogenous as well as exogenous glutamate and with glutamate generated inside synaptosomes from added glutamine. With endogenous glutamate, the stimulation of oxidative deamination was accompanied by a decrease in aspartate formation, which suggests a concomitant reduction in flux through aspartate aminotransferase. Activation of reductive amination of 2‐oxoglutarate by BCH or leucine could not be demonstrated even in synaptosomes depleted of internal glutamate. It is suggested that GDH in synaptosomes functions in the direction of glutamate oxidation, and that leucine may act as an endogenous activator of GDH in brain in vivo.
Manipulating Kv4.2 identifies a specific component of hippocampal pyramidal neuron A‐current that depends upon Kv4.2 expression
Authors: Lauver Aaron , Yuan Li‐Lian , Jeromin Andreas , Nadin Brian M. , Rodríguez José J. , Davies Heather A. , Stewart Michael G. , Wu Gang‐Yi , Pfaffinger Paul J. 
Published: October 2006

AbstractThe somatodendritic A‐current, ISA, in hippocampal CA1 pyramidal neurons regulates the processing of synaptic inputs and the amplitude of back propagating action potentials into the dendritic tree, as well as the action potential firing properties at the soma. In this study, we have used RNA interference and over‐expression to show that expression of the Kv4.2 gene specifically regulates the ISAcomponent of A‐current in these neurons. In dissociated hippocampal pyramidal neuron cultures, or organotypic cultured CA1 pyramidal neurons, the expression level of Kv4.2 is such that the ISAchannels are maintained in the population at a peak conductance of approximately 950 pS/pF. Suppression of Kv4.2 transcripts in hippocampal pyramidal neurons using an RNA interference vector suppresses ISAcurrent by 60% in 2 days, similar to the effect of expressing dominant‐negative Kv4 channel constructs. Increasing the expression of Kv4.2 in these neurons increases the level of ISAto 170% of the normal set point without altering the biophysical properties. Our results establish a specific role for native Kv4.2 transcripts in forming and maintaining ISAcurrent at characteristic levels in hippocampal pyramidal neurons.
Caribbean Transnational Return Migrants as Agents of Change
Authors: Conway Dennis , Potter Robert B. 
Published: October 2006

AbstractThis article challenges several of the firmly held convictions drawn from extant research on return migration to the Caribbean. For many contemporary small island societies undergoing rapid change and transformation, modernization and integration into the wider global economy, today's younger and more youthful return migrants are no longer an ineffective demographic cohort. Despite their numerically small size, many are demonstrating they can be influential “agents of change.” No longer merely returning retirees, they are more diverse, in terms of age, life‐course transitions, class and gendered social positions, family networks, and migration histories. Multiple identities are the rule, rather than the exception, as returnees of different ages choose to live, work (and play) in island society, to give something back to the island home of their parents or of their youth. Many embrace transnational strategies to live in and between two worlds, or more if their family network's reach is multilocal.
Radiocarbon Dating and Archeology in North America
Authors: Johnson Frederick 
Published: October 2006

The history of the development of a radiocarbon chronology shows how the establishment of the times of events and the order of them has greatly improved the understanding of prehistory in North America. This is true also of other parts of the world. Too little has been said of existing discordance between archeologically determined sequences, and interregional associations, and the radiocarbon chronology. It does appear that these will be resolved as additional dates are added and as the results become more finely calibrated so that secular variations may be accounted for.
The collaborative aspect of the venture was apparent at the outset. Nevertheless no one expects an archeologist to delve into nuclear physics and geochemistry, and vice versa. There is great need, nevertheless, for the man in the laboratory to comprehend the difficulties of sample collecting and of judgement of the significance of the source of organic matter to be dated. At the same time, the archeologist must become more familiar with the importance of the various steps in the processing of the sample and with, what is most vital, interpretation of the significance of the numbers that appear on the counters.
The Cholinergic Synapse and the Site of Memory
Authors: Deutsch J. Anthony 
Published: October 2006

A simple hypothesis can explain the results obtained to date if we disregard those results when we wait 30 minutes after original learning to inject. The hypothesis is that, as a result of learning, the postsynaptic endings at a specific set of synapses become more sensitive to transmitter. This sensitivity increases with time after initial learning and then declines. The rate at which such sensitivity increases depends on the amount of initial learning. If the curve of transmission plotted against time is displaced upward with anticholinesterases then the very low portions will show facilitation, and the high portions will cause block (Fig. 8). The middle portions will appear unaffected (unless special experimental tests are made). If the curve of transmission is displaced down with anticholinergics, then the middle portion will appear unaffected and only the very early or late components will show block.
The results are evidence that synaptic conductance is altered as a result of learning. So far it seems (i) that cholinergic synapses are modified as a result of learning and that it probably is the postsynaptic membrane that becomes increasingly more sensitive to acetylcholine with time after learning, up to a certain point. (ii) After this point, sensitivity declines, leading to the phenomenon of forgetting. (iii) There is also good evidence that there is an initial phase of declining sensitivity to cholinesterase or increasing sensitivity to anticholinergics. This could reflect the existence of a parallel set of synapses with fast decay that serve as a shortterm store. (iv) Increasing the amount of learning leads to an increase in conductance in each of a set of synapses without an increase in their number. (v) Both original learning and extinction are subserved by cholinergic synapses.
Depressive Disorders: Toward a Unified Hypothesis
Authors: Akiskal Hagop S. , McKinney William T. 
Published: October 2006

Our scientific understanding of psychiatric syndromes, including the phenomena of depression, has been hampered because of: (i) the use of metapsychological concepts that are difficult to test; (ii) methodological and linguistic barriers that prevent communication among psychoanalysts, behaviorists, experimental psychologists, and psychiatrists; and (iii) the reluctance of psychiatrists to accept animal models as possible approximations of certain aspects of human psychopathology.We have attempted to demonstrate that the animal models simulate some of the central features of clinical depression (for example, helplessness and object loss), thereby allowing one to rigorously investigate them from developmental, behavioral, and biochemical perspectives.The object loss model, as a concrete version of a metapsychological-psychoanalytic concept, has enabled primatologists to study the disruption of an attachment bond. The behavioral model accommodates this concept to a broader generalization: loss of reinforcement or loss of control over reinforcement. We have reviewed the evidence that these processes involve the diencephalic centers of reward or reinforcement, thereby permitting integration of the psychoanalytical and behavioral formulations with the biochemical hypotheses. Also, we have presented data strongly suggesting that the breaking of an attachment bond in the primate represents significant loss of reinforcement that induces helplessness and disrupts motivated behavior.Finally, we have argued that the depressive syndrome could be caused by interactions of genetic, chemical, developmental, and interpersonal factors, all of which impinge on the diencephalic centers of reinforcement.
On the X-ray Diffraction Effects from Solid Fatty Acids
Authors: Wyckoff Ralph W. G. , Hunt Franklin L. , Merwin Herbert E. 
Published: October 2006

Powder reflections, as well as single face reflections of large spacing, have been obtained from palmitic and other fatty acids. Single specimens with all the optical properties of a crystal and giving the same large spacing X-ray reflections as solidified films on glass have been grown from solution of palmitic acid in acetone. This acid, at least, therefore appears to be truly crystalline under these conditions and not in a "smectic" or other sub-crystalline state. Since the X-ray data from this acid are strictly analogous to those from other typical "smectic" substances, it seems necessary further to conclude that no definite X-ray evidence yet exists for this "smectic" state.
The symmetry of palmitic acid is either monoclinic or triclinic and the long carbon chains are not normal to the face producing the large spacing reflections. Such spacings are therefore not direct measures of the lengths of these chains.
By growing single plates of the acid from solution more intense reflections from the long spacings have been obtained than from films made by solidifying the acid on glass or mica. Such single crystals may prove especially useful as gratings in long wave length X-ray spectrography.
Occurrence of Germanium and Arsenic in Meteorites
Authors: Papish Jacob , Hanford Zaida M. 
Published: October 2006

1. Spectroscopic evidence has been obtained of the occurrence of germanium in certain siderites, siderolites and aerolites.
2. Judging from the number and intensity of spectral lines the germanium in these meteorites is present in traces.
3. Germanium has been extracted from Toluca and Welland siderites.
4. Arsenic has been extracted from Toluca and Welland siderites
Responses of Sheep to
Zygadenus gramineus
, "Death Camas"
Authors: McLaughlin Alvah R. 
Published: October 2006

An extract of
Zygadenus gramineus,
"death camas," from which most of the resins had been removed was given intravenously to sheep prepared for recording blood-pressure and respiratory movements.

Following the intravenous injection of this extract there occurred a respiratory inhibition which in the case of the injection of larger amounts of the extract was followed by asphyxia-like rises of blood-pressure.
The graphic record of this asphyxial condition was practically duplicated by closing the tracheal cannula for a short time following the recovery of the animal from the effects of the plant extract.

Although, from a field standpoint, no satisfactory antidote has been found, it has been demonstrated that caffein sodio-benzoate possesses marked powers of stimulation for the respiratory center affected by the depressive substances found in
Zygadenus gramineus.
Public Health Hazards from Electricity-Producing Plants
Authors: Neyman Jerzy 
Published: October 2006

When a new electricity-producing plant is to be built in a given locality it is natural to take into account the public health consequences of the normal operation of each type of plant contemplated. Here, the fossil-burning plants and nuclear facilities come under consideration. I have attempted to show that, in spite of the many important studies performed, there is currently no reliable methodology to estimate how many more cancer cases, and how many more heart attacks and other diseases have to be anticipated as a consequence of the normal operation of this or that type of electric generator. In part, this is because the currently available estimates of radiation effects on humans are based on extrapolations from studies of two kinds. Those of one kind may be exemplified by studies of atomic bomb casualties in Hiroshima and Nagasaki. The other kind are laboratory experiments with lower animals, frequently mice. The unreliability of both kinds of extrapolations is connected with the following circumstances: (i) The omnipresent troublesome phenomenon of competing risks. (ii) The dependence of health effects of a given noxious agent on the preexisting local pollution. (iii) The dependence of health effects not only on the "dose" of an agent, but also on the rate at which the agent is administered. (iv) The noted difficulties of making extrapolations from one mammal to another.
Our obtaining reliable estimates of the public health effects of extra pollution from new industrial plants would seem to depend on a large multipollutant and multilocality epidemiological study being conducted—one requiring the cooperative effort of several governmental agencies. However, a much easier study of certain developments in the vicinity of Rocky Flats, Colorado, might provide important direct information on health phenomena as they occur in real life.
Preliminary Studies of a Cerebral Disorder of Young Chickens
Authors: Delaplane John P. , Stuart H. O. , Hart C. P. 
Published: October 2006

Chicks fed a diet in which corn was the principal ingredient, in contrast to other rations employed, were the only ones in which the typical nervous disorders were noted and typical brain lesions observed upon autopsy.
The preliminary data at hand, although not of a definite nature, would seem to indicate that some factor or factors of the corn used were responsible or at least contributory to this disorder.