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Biomedical subjects

H G Bernstein

Publications and source records attributed to H G Bernstein.

At least 109 records · Page 6Linked to original sources
PubMed1983

The glucagon/glucagon-like immunoreactivities in neurons of the human brain.

Using indirect immunofluorescence and Sternberger's PAP techniques on Bouin-fixed paraffin sections it was possible to show a glucagon/glucagon-like immunoreactivity in the following sites of the human brain: the Lamina V pyramidal cells of the Neocortex, the various neurons of the Hippocampus and Corpus amygdaloideum, the perikarya of neurons in the Nucleus ventromedialis and Nucleus infundibularis (arcuatus), the Nucleus ambiguus and the numerous granular cells of the cerebellar cortex. It was also possible with both techniques to find a similar distribution of the peptide hormones in the perikarya and the proximal parts of the neuronal extensions. Appropriate controls were used to confirm the results. Simultaneously, tissue specimens from the same brain regions were investigated for glucagon by radioimmunoassay. The glucagon content of nervous tissue was found to be much higher than the average glucagon concentration of blood plasma. The highest level of the polypeptide could be revealed for the Hypothalamus (up to 40 times higher than in blood plasma).

Brain Chemistry↗
PubMed1983

Insulin and C-peptide in human brain neurons (insulin/C-peptide/brain peptides/immunohistochemistry/radioimmunoassay).

The regional distribution and cellular localization of insulin and C-peptide immunoreactivities were studied in human cadaver brains using the indirect immunofluorescence method, the peroxidase-antiperoxidase technique, and radioimmunoassay. Products of the immune reactions to both polypeptides were observed in most nerve cells in all areas of the brain examined. Immunostaining was mainly restricted to the cell soma and proximal dendrites. Radioimmunoassay revealed that human brain contains insulin and C-peptide in concentrations much higher than the blood, the highest being in the hypothalamus. These findings support the hypothesis that the "brain insulin" is--at least in part--produced in the CNS.

Aged↗
PubMed1982

Insulin-like immunoreactivity in the human brain- A preliminary report.

The localization and regional distribution of insulin-like immunoreactivity (IRI) was studied in human brain autopsy material using the indirect immunofluorescence technique. A positive reaction for IRI could be observed in many neurons of the hypothalamus, the hippocampus, corpus amygdaloideum, medulla oblongata (especially within the nuclei of cranial nerves IX, X and XII), and the cerebral cortex, whereas the cerebellar cortex was lacking in immunohistochemically detectable insulin-like material. No nerve fibres containing polypeptides could be revealed. Additionally, the insulin content of various brain regions was estimated by radioimmunoassay. Insulin concentrations in human nervous tissue were found to be elevated in comparison to blood plasma levels.

Aged↗
PubMed1982

C-peptide immunoreactive neurons in human brain.

C-peptide/C-peptide-like immunoreactivity was shown to be present in the cytoplasm of the soma and the proximal part of apical dendrites of some pyramidal cells in the Neocortex (Gyrus precentralis) and Hippocampus of man. C-peptide (connecting peptide) is a metabolic product in insulin biosynthesis and its localization in neurons is a proof for extrapancreatic insulin production.

Brain Chemistry↗
PubMed1982

Neurosecretory nerve cells of rat and fish brain are rich in thiol-protein disulphide oxidoreductase (TPO) immunoreactivity.

Thio-protein disulphide oxidoreductase (TPO) was demonstrated in rat and fish brain by use of the indirect peroxidase-antiperoxidase technique. TPO immunoreactivity was found to be widely distributed throughout rat CNS. Whereas most nerve cells possessed only weak immunoreactivity to the enzyme, the neurosecretory cells of Nuc. supraopticus and Nuc. paraventricularis were heavily laden with immune products. In fishes (rudd) the neurosecret-producing neurons of the Nuc. preopticus were the only locus being positive for TPO. From our findings we conclude that thiol-protein disulphide oxidoreductase might be involved into the process of neurophysin synthesis.

Animals↗
PubMed1981

Specific demonstration of rat brain adenylate cyclase in polyacryl amide microgels by a new histochemical procedure.

Adenylate cyclase from rat hippocampus was separated by electrophoresis in polyacryl amide microgels and stained for enzymatic activity using a new histochemical procedure. This method involves the use of AMP-PNP, aminophylline, dithiotreitole, and Sr2+ as "primary" capture ions, thus fulfilling all the demands for a really specific histochemical incubation medium for the enzyme. The incubation of the gels with this medium resulted in the inhibition of other enzymes, which are capable of splitting AMP-PNP (ATP: pyrophosphatase, alkaline phosphatase), whereas adenylate cyclase remained highly active under these conditions. The enzyme was found to be present in two forms in the gels. Both protein bands were stimulated by the addition of various biogenic amines to the incubation medium. One protein band was fully GMP-PNP dependent in its activity. It is reasonable to suppose that these forms are either differently high aggregated molecules of the enzyme or enzyme molecules bound to their regulatory sites.

Adenylyl Cyclases↗
PubMed1981

Insulin immunohistochemistry of rodent CNS: apparent species differences but good correlation with radioimmunological data.

Using an indirect immunofluorescence technique the distribution of insulin was mapped in brains of Wistar strain rats and mice. Insulin immunoreactivity was found to be widely distributed throughout mouse CNS, whereas in rat brain a restriction of immunoreactive material to cerebral blood vessels and ependymal cells and/or tanycytes of the brain ventricles was observed. In radioimmunological studies the amount of insulin (IRI) was estimated for different brain areas (cerebral cortex, brain stem, cerebellum, hippocampus, thalamus and hypothalamus). In the case of Wistar rats very low levels of IRI were found. On the contrary, the same regions in mouse brain contained considerably greater amounts of IRI. The comparison between histochemical and biochemical data revealed a good correlation. It is concluded that part of the insulin measured by radioimmunoassay is associated with neuronal structures.

Animals↗
PubMed1981

Poor evidence for insulin/insulin-like immunoreactivity in the CNS of lower vertebrates.

The localization of insulin/insulin-like immunoreactivity was studied in the brain and the pancreas of an amphibian (clawed frog [Xenopus laevis Daudin]) and in the CNS of two teleost fishes (bream [Abramis brama L.] and rudd [Scardinius erythrophthalmus L.] using the indirect immunofluorescence technique. With exception of cerebellar Purkinje cells no neuronal elements were found to contain insulin-like material. The frog pancreas was characterized by a strong immunofluorescence in cells producing the polypeptide.

Animals↗
PubMed1981

Towards a specific histochemical localization of adenylate cyclase in the rat hippocampus. I. Methodical aspects.

The adequate histochemical demonstration of adenylate cyclase still involves serious methodical problems (low basal activity, fixation procedures, heavy metal ions as capture agents etc.). We have tried to revise fixation approach and composition of incubation medium in order to specify the mode of demonstration of the enzyme. The influence of strontium and barium (instead of lead) as well as dithiothreitole and sodium fluoride on the survive of adenylate cyclase activity was studied using a radiochemical model system.

Adenylyl Cyclases↗
PubMed1981

Immunoreactive glucagon in neurons of various parts of the human brain. Demonstration by immunofluorescence technique.

The presence of glucagon-like immunoreactivity in nerve cells of different parts of the human brain was demonstrated by the indirect immunofluorescence technique. A bright fluorescent reaction was observed in the pyramidal cells of lamina V of the Neocortex. Less prominent concentrations of the glucagon-like material were detected in a few pyramidal cells of the Hippo-campus and in some neurons of the Presubiculum and Subiculum. Within the Corpus amygdaloideum, only a few magnocellular neurons showed a positive reaction. The Hypothalamus was evidenced by a moderate, but widely distributed, reaction in magnocellular and medium-sized nerve cells in different nuclei (especially Nuc. ventromedialis and Nuc. arcuatus). A strong immunofluorescence was localized to some neurocytes in the Nuc. amibigus, and Nuc. n. hypoglassi. The Purkinje cells of the cerebellar cortex were free from immunoreactive material, but fluorescence occurred in some very small nerve cells of the Cerebellum (probably granular cells). A dependence of the strength of immunofluorescence of the time delay between autopsy and death is shown.

Amygdala↗
PubMed1981

[Immunohistochemical evidence of some peptidohormones in the central nervous system of normoglycemic and hyperglycemic rodents (author's transl)].

The content and the distribution of insulin, glucagon and somatostatin were studied in normoglycemic and hyperglycemic rodents by immunohistochemical techniques. A manifest Diabetes mellitus caused a striking decrease in somatostatin immunofluorescence. The insulin content suffered in a less pronounced manner. Data obtained with glucagon did not permit to draw unequivocal conclusions. In general, our findings speak about certain regulatory influence of the brain on glucose homeostasis.

Animals↗
PubMed1980

Failure to demonstrate rat hippocampus adenylate cyclase.

The fate of ATP exposed to rat hippocampal extracts was investigated after their separation by a microdisc electrophoresis tenhnique. It could be demonstrated that the histochemical adenylate cyclase procedure using ATP as substrate is not suitable for specific localization of the enzyme, since other ATP hydrolysing enzymes were also able to convert ATP unless the concentrations of inhibitors reached 1 mM (ouabain) and 40 mM (NaF). With a prolonged incubation time of 18 h further substrate splitting protein zones could be revealed, possibly reflecting activities of enzymes involved in the hydrolysis of degradation products of ATP.

Adenosine Triphosphate↗