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Biomedical subjects

A Dorn

Publications and source records attributed to A Dorn.

At least 163 records · Page 9Linked to original sources
PubMed1977

[Histological and immunohistochemical investigations on the transplanted isolated islets of Langerhans in diabetic rats (author's transl)].

Isologous isolated islets of LANGERHANS were transplanted in the peritoneum and through the portal vein in the liver of diabetic rats. With the help of histological and immunohistochemical investigations, estimation of blood sugar and glucose tolerance tests was tested over a period of 12 month, whether the peritoneum or the liver is more suited as transplantation site for isolated islets of LANGERHANS. After transplantation of islets of LANGERHANS in the peritoneum of diabetic rats the blood glucose decreased and this effect could be maintained over a period of three months. The histological investigations showed strong periinsulinar reactions and the immunohistochemical insulin and glucagon proofs prospered over a period of three months. After transplantation of isolated islets in the liver it resulted in a normalization of blood glucose levels up to 12 months after transplantation and in this time prospered the immunohistochemical insulin and glucagon proof. These results have suggested, that the liver is more suited as transplantation site for isolated islets of LANGERHANS than the peritoneum.

Animals↗
PubMed1977

[The immunofluorescence-microscopical evidence of insulin and glucagon in transplantated isolated Langerhans' islets in diabetic rats and dogs (author's transl)].

With the histochemical immunofluorescence technique were demonstrated the insulin and glucagon in the transplantated isolated Langerhans' islets in the liver at diabetic rats and dogs. Further on were tested the diabetic metabolic level with aid of clinico-chemical methods during the period of investigation (blood glucose, serum insulin, glucose tolerance test). It was found that after transplantation, 1 year by the rats and more than 8 weeks by the dogs, is existing a normoglycemic level. In the transplanted islets were seen a good immunofluorescence of insulin in the B cells and the glucagon in the A cells in all investigated stages.

Animals↗
PubMed1976

Structure and function of prothoracic glands and oenocytes in embryos and last larval instars of Oncopeltus fasciatus Dallas (Insecta, Heteroptera).

1. Active prothoracic glands and oenocytes of last larval stage are both characteristized by well-developed smooth and rough endoplasmic reticulum (ER). Prothoracic glands also show plasma membrane infoldings, but not oenocytes which contain a large number of pleomorphic vesicles. 2. The fine structure of embryonic oenocytes corresponds after blastokinesis with that of active larval and adult cells. Thus, an activity in the late embryo can be assumed. Embryonic prothoracic glands reveal no signs of activity: smooth and rough ER are absent. The subcellular structure resembles that of organ anlagen, i.e. not yet fully differentiated tissue. Hormone synthesis is not likely. 3. Ecdysone titer was determined throughout embryonic development and in mature adults. Although prothoracic glands break down during adult ecdysis, imagines contain in the Calliphora-bioassay active factors: females 0.9 CU/g and males 0.5 CU/g. As sites of synthesis the oenocytes are suggested. 4. A relatively high ecdysone titer of 7 CU/g is measured in newly deposited eggs. The hormone is presumably of maternal origin. Subsequent to blastokinesis the hormone content increases dramatically up to about 180 CU/g, apparently due to endocrine function of the embryo. Oenocytes are proposed as the source of ecdysone during late embryonic development. 5. The function of ecdysone during early and advanced embryogenesis, especially in view of "embryonic molts", is discussed.

Animals↗
PubMed1976

[Enzyme histochemistry of the sand rat pancreas (Psammomys obesus) after different caloric food].

In a complex investigation were evidenced 12 selected enzymes (oxidoreductases and hydrolases) in the pancreas of normoglycemic sand rats (Psammomys obesus). The sand rat developed a spontaneous diabetic metabolism by holding in the vivarium. The material based of animal groups that were fooded ad libitum or after defined dietetic regimes. The topochemical pattern of enzymes in the Langerhans' islets and exocrine acini can be compared between the sand rat groups and with the good investigated model of the Wistar rat. Because enzymhistochemical investigations of the sand rat pancreas absented, were the results compared with the rare specific observations of other animals and the man and the changed metabolic level were discussed under the especially food situation and in diabetes mellitus.

Acid Phosphatase↗
PubMed1976

[Immunhistochemical investigations for evidence of insulin, glucagon and gastrin in the islets of Langerhans of Wistar rats during the development (author's transl)].

Insulin, glucagon and gastrin were investigated immunohistochemically in the islets of Langerhans in 14, 15, 17, 18 and 20 days old embryos, in newborn, 2, 5, 10, 20 and 30 days old and adult Wistar rats. The results were documented in series of microphotos. By means of the indirected immunofluorescence technique the insulin and glucagon were observed from the 18th day of the prenatal development in the B- resp. A-cells of the islets. Than the intensity of the fluorescence shows a continual increase during the development. In the islets cells of the developing stages and adult rats can't immunohistochemically evidenced the gastrin. The important results were discussed from the standpoint of the development physiology.

Animals↗
PubMed1976

[Transplantation of isolated islets of Langerhans into the liver of diabetic dogs (author's transl)].

Isolated islets of Langerhans were transplanted through the portal vein in the liver of 8 diabetic dogs; In 4 dogs a homologous transplantation was performed and another group of four dogs received isolated islets from their sisters or brothers. In both groups, there was an immediate effect on the blood glucose level. After pancreatectomy and injection of Alloxan the blood glucose rose to between 350 and 420 mg per 100 ml and after islet implantation the blood glucose decreased between 80 to 160 mg per 100 ml. The iv GTT'S were after islet implantation clear better than in the diabetic control animals. These results could maintained in the recipients with homologues islets over a period of 6 to 8 weeks and in the other group of dogs over a period of 6 to 12 months. We were able to show, that the islet implantation in the liver of diabetic dogs did not disturb the microscopic architecture of the liver. No signs of portal hypertension, hepatic congestion and embolism were found.

Animals↗