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Biomedical subjects

A Dorn

Publications and source records attributed to A Dorn.

At least 145 records · Page 8Linked to original sources
PubMed1981

[Making of anatomical dry preparations from voluminous hollow organs by use of SYSpur-solid foam (author's transl)].

The authors describe an approach to make anatomical dry preparations from voluminous hollow organs (gastro-intestinal tract, urinary bladder etc.) by "foaming-out" with polyurethane-solid foam (SYSpur). Injections of silicon resin material into intestinal veins or arteries increase the value of demonstration by relief like featuring of the vessel system. The corrosion of "foamed-out" intestinal section after injection of Kallocryl M is presented as a new method. The preparations possess an improved stability in comparison with simple corrosion -- preparations from hollow organs. Furthermore, the solid foam matrix may be used as a topographical reference.

Animals↗
PubMed1980

Are certain peculiarities in the distribution of somatostatin-like immunoreactivity (SLI) in the brain of sand rats (Psammomys obesus) possibly connected with an altered carbohydrate metabolism?

The hypothalamic and extrahypothalamic distribution of somatostatin-like immunoreactivity (SLI) was investigated in fed adult sand rats (Psammomys obesus) of both sexes using the immunofluorescence technique. Blood glucose and insulin concentrations were determined in these animals prior to decapitation. In a blind study, the amount of immunofluorescence of certain CNS areas and the glucose: Insulin ratio were compared and found to be connected: High amounts of SLI were detected in the dorsal hippocampus, in some hypothalamic nuclei and the median eminence of rats displaying low glucose levels. Sand rats with high blood glucose values did not show SLI in the hippocampal formation and the immunofluorescence of the circumventricular (hypothalamic) regions and the Eminentia mediana was drastically reduced. A possible correlation of SLI with insulin concentrations in the blood could not be revealed. The data obtained are discussed as a possible expression of a CNS influence on glucoregulation in this species.

Animals↗
PubMed1980

[Demonstration of an epidermal SH-protease inhibitor in normal epithelium and in some human neoplasms--an immunological study (author's transl)].

Using a specific antiserum, it was possible to demonstrate (with the Ouchterlony-test, immunofluorescence and peroxidase-antiperoxidase reaction) that the epidermal thiolprotease inhibitor was present in all the squamous epithelia tested by us, e.g. oesophagus, vagina and portio. Immunological methods further showed that epidermoid carcinoma of the skin, squamoepithelial carcinomas of the portion and oesophagus, and squamoepithelial carcinoma of the lung contained an immunoreactive protein reminiscent of the epidermal protease. The immunoreactive protein typical of squamous epithelium was also visible in part of the anaplastic lung carcinomas, which means that the determination of the inhibitor may be of significance in the classification of lung tumors.

Carcinoma, Squamous Cell↗
PubMed1979

Natural H Currents Traverse Growing Roots and Root Hairs of Barley (Hordeum vulgare L.).

With the aid of an extracellular vibrating electrode, natural electric fields were detected and measured in the medium near growing roots and root hairs of barley seedlings. An exploration of these fields indicates that both the root as a whole, as well as individual root hairs, drive large steady currents through themselves. Current consistently enters both the main elongation zone of the root as well as the growing tips of elongating root hairs; it leaves the surface of the root beneath the root hairs. These currents enter with a density of about 2 microamperes per square centimeter, leave with a density of about 0.5 to 1 microampere per square centimeter, and total about 30 nanoamperes.Responses of the natural fields to changes in the ionic composition of the medium as well as observations of the pH pattern in the medium near the roots (made with bromocresol purple) together indicate that much of the current consists of hydrogen ions. Altogether, H(+) ions seem to leak into growing cells or cell parts and to be pumped out of nongrowing ones.

Journal Article↗
PubMed1978

[The immunohistochemical demonstration of the Thiol: proteindisulfid oxidoreductase (TPO) in pancreas and isolated Langerhans'islets. A light-, fluorescent- and electron microscopic study (author's transl)].

Thiole: Protein disulfide Oxidoreductase (E. C. 1.8.4.2) is capable of catalyzing thiole-disulfid exchange reactions and might have an important function in both protein biosynthesis and degradation. By using histochemical methods we were able to demonstrate the localization of this enzyme in the Langerhans'islets and in the acinus cells of rat pancreas. The reaction of the acinus cells, however, was much weaker than that of the islets. Electron microscopic experiments revealed the enzyme to be located in the outer membrane of the nucleus, in the membranes of the endoplasmic reticulum and B-cell granules, and in the plasmalemma also. All these structures are known to be involved in the insulin biosynthesis and secretion. There is a good correlation between morphological and biochemical findings. In acinus cells there are a few reaction in the outer nucleus membrane, the membranes of the endoplasmatic reticulum, and the plasmalemm.

Animals↗
PubMed1978

[The immunhistochemical investigation of trypsin and trypsin-like-activity in the small intestine, pancreas and isolated Langerhans islets. A light-, fluorescent- and electron microscopic study (author's transl)].

By means of the indirect immunofluorescence and immunenzyme technique trypsin and trypsin-like activity in fixed cryostate sections of pancreas and gut and pellets of isolated pancreatic islets respectively were investigated using specific antiserum against trypsin. The enzyme was demonstrated in the cytoplasma of the acinus cells, the epithel cell of the intercalated ducts and the excretory (interlobular) ducts of the exocrine pancreas. By light and fluorescence microscopy we could also localize a high activity in pancreatic islets. Results taken from electron microscope show the enzyme in the region of the peripheral endoplasmatic reticulum, the surface of the mitochondria, the zymogen granules of the acinus cells and in the region of the membranes of the endoplasmatic reticulum and in the granules of the B-cells of the pancreatic islets. These results are discussed in correlation with biochemical data concerning the importance of trypsin/trypsin-like activity in the specific conversion of prohormones into hormones.

Animals↗
PubMed1978

[Results of islet transplantation in diabetic dogs].

The influence of histocompatibility on islet transplantation in dogs was studied. Donors and hosts were chosen by help of the macrophage-electrophoresis-mobility test. By subtotal pancreatectomy and twice applying streptocotocin diabetes was successfully induced in recipient animals. Isolation of pancreating islets from the donor was done by means of the collagenase method combined with the Ficoll-gradient-separating technique. The grafting occurred via portal vein into the liver. Significant decrease of blood sugar during 10 weeks was observed in animals with good compatibility. This effect lasted only 14 days in cases of bad compatibility. Concentrations of insulin in the portal vein and superior caval vein 4 weeks after grafting was lower in cases with high-grade histoincompatibility. The duration of functioning of transplanted islets depends on the histocompatibility.

Animals↗