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Biomedical subjects

A Andersson

Publications and source records attributed to A Andersson.

At least 397 records · Page 22Linked to original sources
PubMed1976

Carcinoma of the pancreas.

Study of hospital records of 146 patients with carcinoma of the pancreas from 1952 to 1971 revealed that 74 per cent had had abdominal pain and 65 per cent jaundice. Abdominal pain was the commonest symptom of carcinoma of the head as well as of the body and tail. Diabetes mellitus was four times as common among the patients with carcinoma of the pancreas as among the population in general. The interval between the onset of symptoms and diagnosis of the disease was the same in both decades of the 20-year period, but the survival time after operation was longer in the second 10-year period. Pancreatoduodenectomy was possible in only four of the 138 patients operated on, and one of them died postoperatively. The three patients who survived the operation survived significantly longer than the 87 in whom an anastomosis had been established between the bile ducts and the intestine. Forty-one patients were subjected to surgical exploration only. No difference in survival time was found between the two last-mentioned groups.

Adenocarcinoma↗
PubMed1976

Insulomas and multiple endocrine neoplasia.

Seventy-eight patients with insuloma diagnosed between 1959 and 1968 in Sweden were studied for neoplasia in other organs. Twenty-one patients had beta-cell islet tumors, 14 Zollinger-Ellison's syndrome and non-beta-cell islet tumors, while no endocrine activity was demonstrated in 43 patients. Of the last-mentioned group, 9 patients had co-existing disease of other endocrine organs. In 10 patients, non-endocrine organs were found to be affected by malignant diseases. It appears probable that the tissue of the pancreatic islets, like parathyroid tissue, can react with hyperplasia with a later development of adenoma, secondary to tumors in other organs.

Adenoma, Islet Cell↗
PubMed1976

Regeneration of islet cells.

The number of functionally intact B-cells in the islet organ is of decisive importance for the development, course and outcome of diabetes mellitus. Generally speaking, the total B-cell mass reflects the balance between the renewal and loss of these cells. While factors resulting in damage and degeneration of the B-cells have attracted much attention there has been relatively little interest in the kinetics and regulation of B-cell proliferation. This paper briefly reviews the literature in the latter field with special attention to B-cell renewal in various kinds of diabetes. In early fetal life both the endocrine and exocrine pancreatic cells probably arise from a common "protodifferentiated" cell type. The islets subsequently grow according to a regular pattern characterized by a symmetrical distribution of the islet volume in relation to islet diameter. The growth of the islets reflects the replication of both B-, A1- and A2-cells in individual islets. Whether new islet cells are derived also from duct epithelium or by transformation of differentiated acinar cells remains a matter of controversy. The ability of the differentiated B-cell to replicate in adult life has been confirmed in many studies. Factors believed to increase the rate of replication in vivo include a high caloric intake, hypoglycemic sulfonylureas, various hormones and hyperglycemia. Recent studies in vitro have so far confirmed the mitogenic action of a high extracellular glucose concentration. The renewal of B-cells in diabetes has been studied in several animal models. Both in experimental diabetes, such as that induced by alloxan, and in hereditary diabetes, exemplified by the diabetic mutant mouse (gene symbol db), there is initial stimulation of the mitotic rate during development of hyperglycemia followed by a notable decrease in the B-cell renewal. In the diabetic mouse the decreased proliferation of B-cells is paralleled by the appearance of fulminant diabetes. These and other data suggest a limited capacity for B-cell proliferation, which may differ between species. According to this hypothesis, there is an increased risk of developing diabetes once the predetermined potential for B-cell division has been exhausted.

Animals↗
PubMed1976

Tissue culture of isolated pancreatic islets.

The ability of the pancreatic B-cell to synthesize and secrete insulin in tissue culture has been established in several studies, most of which involved culture of different preparations of fetal pancreas. In all these studies, however, a substantial admixture of non-endocrine cells complicated a more detailed study of the islet cell. In order to overcome these difficulties we have developed a method for in vitro culture of isolated pancreatic islets, which is well suited for evaluating both morphologic and metabolic changes of the islet cells induced during prolonged culture periods. The present paper will review briefly the work performed on culture of isolated pancreatic islets with special attention to the influence of different culture conditions on the in vitro survival of the explanted islet specimens. It was shown that various kinds of pancreatic islet specimen including isolated human pancreatic islets can be successfully cultured provided that they do not exceed an upper critical size limit and that calf serum is added to the culture medium. The functional characteristics of the cultured islet cells were markedly influenced by the glucose concentration of the culture medium. Thus several signs of hyperactivity were observed in islet cells subjected to a high glucose concentration, while exposure for one week to a subnormal extracellular glucose concentration led to an impairment of their specific functions. Furthermore it was found that L-leucine and B-hydroxybutyric acid were able to replace glucose as a long-term stimulus of the insulin biosynthesis, while succinate and HB 419 did not share this property.

Animals↗
PubMed1975

Glucose dependent alterations of mitochondrial ultrastructure and enzyme content in mouse pancreatic islets maintained in tissue culture: a morphometrical and biochemical study.

Isolated islets of Langerhans from mice were maintained in tissue culture for one week at either a high (28 mM) or a low (3.3 mM) extracellular glucose concentration. Electron microscopic morphometry by means of stereological methods revealed a much greater volume of mitochondria in islet cells cultured at low glucose than in those cultured at high glucose. The former islets also showed a higher activity of the mitochondrial marker enzyme, L-3-hydroxyacyl-CoA-dehyrogenase (E.C.1.1.1.35). These results indicate a true mitochondrial hypertrophy at the low glucose concentration. Although it is known from previous studies that the islet cell metabolism is diminished after low-glucose culture, the present observations of an increased mitochondrial volume probably do not reflect a degenerative process, but rather adaptive changes towards oxidation of energy yielding substrates other than glucose.

Alcohol Oxidoreductases↗
PubMed1975

Volvulus of the cecum.

A series of 37 patients with cecal volvulus treated at three different Swedish hospitals during the years 1952-1973 is presented. The symptoms, physical findings and radiologic features are presented. The associated factors found at operation are described and their possible role in provoking torsion is discussed. In 5 patients the idagnosis did not become clear untio autopsy. Thirty-two patients were subjected to operation. The operation consisted of detorsion in 11 cases, cecopexy in 10, cecostomy in 3 and cecopexy plus cecostomy in 3 patients. The remaining 5 patients were subjected to right sided hemicoloectomy. Of these 5 patients one died postoperatively. There were 6 postoperative deaths after other forms of surgery. The survivors were followed, and the mean followup period was 7 years. There was recurrence in only two patients, both treated with cecopexy. The controversial problem of the preferable surgical method is discussed and a review is given of results in series reported during the last 15 years. It was concluded that when the bowel is viable, cecopexy is the treatment of choice while hemicolectomy should be performed in cases with gangrene.

Adolescent↗
PubMed1975

The role of scintigraphy in detection of liver metastases from gastrointestinal carcinomas.

In 61 patients with gastrointestinal carcinomas the results of liver scintigraphy with 99mTc sulphur colloid were correlated with the results from operations or autopsies. Agreement was obtained in 90% of patients. Compared with celiac angiographic findings, scintigraphy of the liver was considerably more reliable in indicating liver metastases of gastrointestinal carcinomas.

Gastrointestinal Neoplasms↗
PubMed1974

Biosynthesis of glucagon in isolated pancreatic islets of guinea pigs.

1. The biosynthesis of glucagon in guinea-pig A(2) cells was investigated by incubation of isolated islets of Langerhans in the presence of [(3)H]tryptophan for periods of up to 14 days. Proteins were extracted from islets and incubation media and analysed by gel filtration. 2. In addition to very-high-molecular-weight (100000) proteins, the principal tryptophan-containing biosynthetic product after incubation for up to 17h was a protein of minimum mol.wt. 9000, which co-eluted on gel filtration with a peak of glucagon-like immunoreactivity, but was apparently devoid of biological activity in a fat-cell assay. A discrete peak of labelled glucagon was only recovered after incubation for at least 6 days. Losses of glucagon during the extraction and rapid secretion of newly synthesized glucagon into incubation media were excluded as reasons for the lack of recovery of labelled hormone from islets after shorter incubations. 3. The 9000-mol.wt. protein was localized to A(2) cells in experiments using B-cell-depleted islets, and to A(2)-cell granules by subcellular fractionation and electron-microscopic radioautography. Only glucagon was secreted into the incubation medium. 4. Possible relationships between the 9000-mol.wt. protein and glucagon are discussed in the light of postulated mechanisms of glucagon biosynthesis.

Adipose Tissue↗