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Biomedical subjects

A Dorn

Publications and source records attributed to A Dorn.

At least 109 records · Page 6Linked to original sources
PubMed1985

Localization of cholecystokinin immunoreactivity in the human brain with special reference to ontogeny.

The cellular localization and regional distribution of peptides of the gastrin/cholecystokinin family was investigated in human fetal, neonatal and adult brains by use of immunohistochemical techniques. It could be revealed that a cholecystokinin-like immunoreactivity is already present in human brain at the 11/12th gestational weeks. With the 19th week a strong increase in number of CCK reactive cells and the reaction intensity is obvious. The data are compared with the distribution pattern of the adult brain. Our data permit to conclude that gastrin/CCK-related material might play roles independent of neurotransmitter functions during early human brain development.

Aged↗
PubMed1985

Immunocytochemical characterisation of human pituitary adenomas.

Immunohistochemical and histological investigations were undertaken on 24 surgically-removed pituitary adenomas. By histology (haemalu-eosin staining), 7 chromophobe, 12 acidophil and 5 basophil pituitary adenomas were revealed. For immunohistochemical purposes the peroxidase-antiperoxidase technique was applied. Primary antisera against 10 hormones were used. By immunohistochemistry, 7 prolactin-containing, 2 TSH-containing, 2 GH-containing and 1 beta-endorphin-containing pituitary adenomas were identified. Furthermore, 1 mixed thyrotropic-prolactin human pituitary adenoma was detected. A possible connection between histological and immunocytochemical findings is discussed.

Adenoma↗
PubMed1984

Proctolin-related material in the mouse brain as revealed by immunohistochemistry.

By use of a specific antiserum against the insect peptide proctolin we were able to identify proctolin-immunoreactive neurons in the mouse brain. These nerve cells belong to the nuc. mesencephalicus n. trigemini. Furthermore, the antiserum stained very few nerve fibers with varicosities in the immediate neighborhood of the roof of the third ventricle. The chemical identity of the immunoreactive material with genuine proctolin remains to be elucidated.

Animals↗
PubMed1984

Cerebral insulin-like immunoreactivity in rats and mice. Drastic decline during postnatal ontogenesis.

We studied the behavior of the insulin-like immunoreactivity in brains of rats and mice during the first 20 d post natum by immunohistochemistry and radioimmunoassay. It was found that a dramatic decline in the concentration of the peptide, accompanied by a strong reduction of immunoreactive cells, takes place during this period. A possible role of cerebral insulin as a promoter of nerve cell growth and development is briefly discussed.

Aging↗
PubMed1984

Relationship between insulin secretion and pancreas morphology in subjects with chronic pancreatitis.

In order to investigate whether a relationship exists between in vivo insulin secretion and islet mass, 8 patients suffering from severe chronic relapsing pancreatitis were studied before and after pancreatectomy by glucose-glucagon-test (per os 1.75 g glucose; i.v. glucagon 0.01 mg/kg b.w.) and by intravenous glucose-tolerance-test (iGTT) (i.v. glucose 0.33 g/kg b.w.). Postoperative in vitro assessments of pancreatic insulin and alpha-amylase content were performed, and morphometric studies were carried out. Patients were characterized by reduced c-peptide secretion when compared with healthy subjects. The c-peptide response to the glucose-glucagon-test correlated well with the morphometrically estimated exocrine and islet tissue mass (P less than 0.05) and with the content of insulin and amylase in the tissue. The findings suggest that in subjects suffering from severe chronic relapsing pancreatitis the maximal insulin response might represent a parameter for the patient's islet mass.

Adult↗
PubMed1984

Electric Currents around Growing Trichoderma Hyphae, before and after Photoinduction of Conidiation.

Electric currents were measured around Trichoderma harzianum (Rifai) hyphae using an extracellular vibrating electrode. A steady current enters growing hyphal tips and along the side of the apical millimeter. In addition, outward currents were detected at about one-ninth of the locations tested, 60 to 150 minutes after illumination but not in dark controls. This sporadic, localized outward current pattern might be an early biophysical response to blue light.

Journal Article↗
PubMed1984

Brain gastrin/CCK immunoreactivity in sand rat (Psammomys obesus): decrease of number of positive neurons in diabetic animals.

Gastrin/CCK immunoreactivity appears to be widely distributed throughout the mammalian CNS, being most abundant in the cerebral cortex [Vanderhaeghen et al. 1975; Straus et al. 1977; Beinfeld et al. 1981]. Besides its putative role as a co-transmitter in dopaminergic neurotransmission [Hökfelt et al. 1980], cholecystokinin is apparently involved in the central regulation of appetite and satiety [Gibbs et al. 1973; Antin et al. 1975; Parret and Batt 1980; Smith 1980; Smith and Gibbs 1981] Furthermore, it has been shown that the brain concentration of the peptide is decreased in genetically obese mice as compared to non-obese animals [Strauss and Yalow 1979]. The sand rat (Psammomys obesus) is a desert rodent which tends to become diabetic when it is fed with normocaloric diet and restricted in movement [Haines et al. 1965; Hahn et al. 1971]. However, the usefulness of this animal as a paradigm of diabetes is now being revised, since because in its typical expression this metabolic dysfunction appears to be an obesity syndrome [Rice and Robertson 1980]. Therefore, it seems to be necessary to study the distribution of gastrin/CCK-immunoreactive nerve cells in the brain of normal and diabetic (obese) sand rats to get further information about mechanism underlying the development of this form of diabetes.

Animals↗
PubMed1984

Insulin-like immunoreactivity in the rat brain during postnatal ontogenesis.

The regional distribution and the cellular localization of insulin-immunoreactive material in the rat brain has been studied during postnatal ontogenesis by use of radioimmunoassay and immunocytochemistry. It could be shown that there is a decrease in the amount of the peptide in the rat brain during postnatal maturation of the organ. This decline in insulin concentration is morphologically evident by a strong reduction of insulin positive nerve cells. Our findings support the hypothesis that insulin might play important roles as a nerve growth-promoting factor.

Age Factors↗
PubMed1984

[Immunoreactive insulin in the CNS of human fetuses and newborn infants of metabolically healthy and diabetic mothers--an immunohistochemical study].

The cellular localization and regional distribution of "insulin-like immunoreactivity" and "C-peptide immunoreactivity" were studied in brains of fetuses and newborns from normoglycaemic and diabetic mothers using immunohistochemical techniques. It is shown that "insulin-like material" and "C-peptide-like material" occur in the same nerve cells. No differences in regard to the localization of both polypeptides exist between abort material from normoglycaemic and diabetic mothers.

Brain Chemistry↗
PubMed1984

[Behavior of small molecular cysteine proteinase inhibitors in lung cancers and surrounding tissue].

In this work, we have studied the occurrence of acid and neutral cysteine proteinase inhibitors in 3 histologically different lung cancers. The acid cysteine proteinase inhibitor ( ACPI ) seems to be associated to squamous differentiation as our previous observations have shown. As a new observation we could show that the neutral cysteine proteinase inhibitor ( NCPI ) was localized in alveolar macrophages.

Adenocarcinoma↗
PubMed1983

Insulin- and glucagonlike peptides in the brain.

The cellular localization and regional distribution of insulin- and glucagonlike substance, C-peptide-like immunoreactivity, thiol:protein disulphide oxidoreductase, TPO (E.C.1.8.4.2.), and insulin/glucagon-specific proteinase, ISP (E.C.3.4.22.-), are studied in the CNS of man, adult and juvenile rats, mice, tortoises, and frogs by use of immunohistochemistry. Furthermore, the content of immunoreactive insulin, glucagon, and C-peptide was estimated in human cadaver brains by radioimmunoassay. It could be shown that insulinlike immunoreactive material is widely distributed in the human brain and the CNS of juvenile rats as well as in mice, whereas in the CNS of adult rats and nonmammalian animals (frogs, tortoises) the polypeptide is restricted to a few nerve cell populations. C-peptide immunoreactivity was demonstrated in human CNS in the same nerve cells as insulin. By use of two different glucagon-antisera it was revealed that gut-type glucagon occurs in many nerve cells of human and mouse brains, as well as in the CNS of juvenile rats. On the other hand, pancreas-type glucagon was less widely distributed in the human brain and nearly not detectable in the CNS of mice and rats. With the exception of neurosecretory nerve cells, there was a high degree of coincidence between the localization of insulin and TPO. The immunoreaction against the ISP antiserum was weak, but correlated well with the distribution of insulin-immunoreactivity. The occurrence of TPO and ISP in the brain demonstrates the ability of nervous tissue to degrade insulin and glucagon. By radioimmunoassay it was established that human brain contains insulin, glucagon and C-peptide at concentrations that exceed blood levels. We conclude from our data that, at least in part, cerebral insulin and glucagon are products of the brain itself.

Animals↗
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↗