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At least 19 recordsLinked to original sources
PubMed1977

[Presence of biogenic amines in the Langerhans' islets of the sand rat (Psammomys obesus) (author's transl)].

The islets of Langerhans of sand rats (Psammomys obesus) have been investigated ultrahistochemical in order to demonstrate biogenic amines. It could be found that amine containing vesicles with a diameter of 600 to 700 nm from the type of catecholamine granules exist in A-cells as well as in B-cells. Further, 2 very rare cell types not containing specific hormone granules could be found. These cells contain particles, in one case similar to catecholamine granules and in the other case representing serotonine-like granules according to their electron optical properties. It can be stated that the sand-rat belongs to the species containing amines in A- and B-cells. Moreover they contain 2 amines simultaneously. The importance of the amines for the regulation of the hormone secretion of the islets of Langerhans is discussed and the connections to the diabetes mellitus are refered to.

Animals↗
PubMedDate not supplied

Quantitative electron-microscopic studies of langerhans islets in normoglycemic chinese hamsters of a diabetic strain.

On the basis of previous studies of the retina and the pituitary, normoglycemic Chinese hamsters from a diabetic strain were divided into two groups, depending on the thickness of their capillary basement membrane and on the number of somatotrophs. Both values were significantly lower in group I than in group II. Quantitative electron microscopy of the islets of Langerhans showed in group II a tendency to a volume increase for A-cells, to a decrease for D- and B-cells. Also the number of B-granules and the surface area of electron dense material deposited in B-cells appeared to be increased in group II. Hypotheses are offered to explain the islet changes in correlation to previous findings in the retina and pituitary.

Animals↗
PubMed1975

Synthesis of proinsulin and large glucagon immunoreactivity in isolated Langerhans islets from EMC-virus infected mice.

The protein synthesis in normal and in EMC-virus infected mouse islets of Langerhans was investigated. Mouse large glucagon immunoreactivity was determined by an immunoassay after chromatographic separation. It was characterized as a peptide of 16 000 MW with in intracellular half-life of 35-45 min. The proportional reduction of void volume proteins, large glucagon immunoreactivity and proinsulin synthesis after infection shows, that both alpha- and beta-cells are damaged by the virus. A reduction in the synthesis of the three protein fractions was already found 6 hrs after inoculation of the virus and remained nearly constant for 48 hrs. An almost complete breakdown of protein synthesis occurred 60 to 70 hrs after infection and was paralleled by the first light microscopic changes in the islets. The stimulation of proinsulin synthesis by glucose was preserved for 48 hrs after EMC-virus infection.

Animals↗
PubMed1975

Effect of quinaldic acid and its relatives on insulin-release from isolated Langerhans islets.

Influence of quinaldic acid on insulin release from isolated Langerhans islets of rats was studied. It was found that quinaldic acid by itself caused insulin release on the one hand and that it inhibited the second phase of glucose-induced insulin release on the other. A possible mechanism concerning the effect of quinaldic acid on beta-cells of Langerhans islets is presented.

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↗
PubMed1977

[Computer analyse of ultrahistochemical observed metal containing secretory granules in Langerhans islets cells of normoglycemic and diabetic rat].

Metal-containing secretory granules of alpha 2-cells of the LANGERHANS' islets of normal and alloxan-diabetic rats were stained for electron microscopy by a special method. Thereafter the electron micrographs were analysed by the Quantimet 720 image analysing computer with respect to size of the granules and their quantitative distribution in classes. The following statistical tests verified significant differences between the distributions of the secretory granules under normal and diabetic conditions. The secretory granules from alloxan-diabetic animals were diminished distinctly. The examination by image analysing computer confirmed objectively observations, we have made and published formerly.

Animals↗
PubMed1979

[Autotransplantation of Langerhans' islets in a case of total duodenopancreatectomy (author's transl)].

A 36-year-old man suffering from chronic pancreatitis involving the whole organ had total duodenopancreatectomy. The Langerhans' islets were isolated from the extirpated organ and transplanted into the liver via portal artery. Insulin substitution could be lowered from 50 I.U. to 12 I.U. by the 5th post operative day. Repeatedly, raised insulin levels could be verified in response to high blood sugar loads. C-peptide and glucagon were also found. 7 months after transplantation the islets still seem to be functioning.

Adult↗
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↗
PubMed1975

Isogenic and allogenic transplatation of isolated langerhans islets into the liver.

This preliminary experimental report confirms the previous interest of isolated endocrine islet transplantation. Moreover a new "privileged position" for the islets grafts is proposed and is as uneventful as a liver biopsy. The functional value of this grafting procedure has been assessed on biological and functional criteria. The transplanted islets are easily retrievable and histological and especially immunocytochemical studies demonstrate the morphological behaviour of such islets. Finally the preliminary survival of allogeneic grafts into the liver supports the concept of the role of the liver during enhancement of facilitation and will be the subject of further investigations.

Animals↗
PubMed1978

[Autotransplantion of Langerhans islets after total duodeno-pancreatectomy in a patient with chronic pancreatitis (author's transl)].

Total duodenopancreatectomy was performed in a 36-year-old man because of global chronic pancreatitis. Islets cells were isolated by collagenase digestion from the resected pancreas and re-implanted into the liver via the portal vein. Until the sixth postoperative day the amount of insulin required fell from 54 IU initially to 10 IU per day. Serial insulin determination demonstrated secretion by the implanted cells.

Adult↗
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↗
PubMed1975

[The effect of preparative pancreatic digestion with collagenase on the glucose stimulated insulin secretion of isolated Langerhans islets].

Pancreatic islets of wistar rats, isolated after 15 min of digestion with collagenase, secreted insulin in response to 15.0 mM glucose within 2 min and showed the typical sigmoidal glucose response during an incubation time of 15 and 60 min, respectively. Islets, isolated after 35 min of digestion with collagenase, responded with delay after stimulation with glucose (after 15 min of incubation), and are characterized by an increased "release" in the presence of 2.5 mM glucose.

Animals↗
PubMed1976

Ultrastructure of B-cells of Langerhans islets in rats after the administration of L-leucine.

The results of studies with electron microscope supported the earlier biochemical findings on the stimulation of insulin secretion with the aid of L-leucine. The changes of the cell organelles of B-cells showed that both the synthesis and the release of insulin were activated, while the secretion by specific granules was unchanged. The stimulation of B-cells was accompanied by numerous membrane-like structures ("myelin-like figures") which were presumably formed from the endoplasmic reticulum.

Animals↗
PubMed1978

Experimental hypoglycemizing tumor of B-cells of Langerhans islets produced by the combined action of streptozotocin annd nicotinamide in the rat.

Young male and female Wistar-Velaz rats were treated with streptozotocin-nicotinamide combination according to the method of Rakieten and examined periodically for 23 months for fasting and postprandial glycemia, by intravenous, intraperitoneal or intragastric glucose tolerance and tolbutamide tests with the aim to detect in vivo the experimentally produced nesidiomas. One male rat with severe hypoglycemia, apparent first on tolbutamide test after twelve months, later also on glucose tolerance test and fasting hypoglycemia associated with paraplegia with macroscopically and microscopically documented nesidioma is described. The exstirpation of this nesidioma was followed first by normalization and later by development of latent diabetes.

Adenoma, Islet Cell↗