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Biomedical subjects

A Andersson

Publications and source records attributed to A Andersson.

At least 361 records · Page 20Linked to original sources
PubMed1979

Islet implantation normalises hyperglycaemia caused by streptozotocin-induced insulitis. Experiments in mice.

Islet-cell deterioration in juvenile diabetes mellitus may be due to an autoimmune reaction, possibly involving both circulating islet-cell antibodies and an inflammatory process in the islets of Langerhans. Replacement of deteriorated islet cells by implantation of normal ones is now under investigation in many laboratories. The present study does not support the assumption that such islet transplants should be affected in the same way as the endogenous islets. Diabetic mice with a cell-mediated immune reaction to their pancreatic islets, induced by repeated injections of low doses of streptozotocin, were used as recipients. Isogeneic islets implanted intrasplenically in these animals were as effective in producing normoglycaemia as were those injected into animals made diabetic with a single bolus dose of streptozotocin. No inflammatory reaction was seen in the implanted islets, irrespective of the regimen of the preceding streptozotocin treatment. This finding suggests that islet-cell implantation may be attempted in insulin-requiring diabetic patients, even if the cause of the disorder is an inflammatory lesion of the patient's own islets.

Animals↗
PubMed1979

Preservation of beta cell function in adult human pancreatic islets for several months in vitro.

Islets of Langerhans were isolated from four human kidney donors, aged 16 to 21 years by the collagenase method described for isolation of rodent islets. So far the human islets have been kept in tissue culture, without attachment, in medium RPMI 1640 supplemented with 10% calf serum for more than 9 months, with preservation of the ability to release insulin in response to glucose stimulation. Replacement of calf serum with serum from normal human subjects did not affect B-cell survival, but resulted in elevated insulin values partly due to lower insulin degrading activity. Thus the described technique presents a valuable tool for studying chronic effects of metabolites and hormones on islet function, as well as for islet storage prior to transplantation into humans.

Adolescent↗
PubMed1979

Release of insulin in vitro from normal and duct-ligated rat pancreas.

Ligation of the pancreatic duct causes atrophy of the acinar cells but leaves the endocrine tissue intact. In the present study, a partial ligation of the pancreatic duct was performed in the rat, and the in vitro insulin response to glucose was compared from both the atrophic and non-atrophic portions of the pancreas. Subsequent morphological studies of the duct-tied portion of the pancreas indicated a complete lack of acinar cells and a possible neoformation of ducts, fat cells and connective tissue. However, islets were present in normal amounts and appeared well perserved. Measurements of the insulin release in vitro from this ligated pancreatic tissue showed that an increase of the glucose concentrations from 3.3 to 16.7 mmol/1 resulted in a six-fold stimulation. A further two-fold stimulation was seen after addition of theophylline to the high-glucose incubation medium. In addition, only under the latter conditions was there a significantly increased insulin release from both non-atrophic portion of the pancreas and from the pancreas of sham-operated animals. It is concluded that duct ligation does not diminish the glucose sensitivty of rat islet B-cells. Thus, the present study does not support the view proposed previously that islet tissue is functionally of a foetal nature following duct ligation.

Animals↗
PubMed1978

Opposite effects of starvation on oxidation of [14C]adenosine and adenosine-induced insulin release by isolated mouse pancreatic islets.

To test further the hypothesis that ribonucleosides stimulate insulin secretion and biosynthesis by producing metabolic signals, the effects of starvation on adenosine-stimulated insulin production and the oxidation of adenosine by isolated mouse pancreatic islets were examined. No direct correlation was found between the metabolic flux and insulin secretion, since the starvation-induced impairment of the adenosine-stimulated insulin secretion was accompanied by an increased rate of adenosine oxidation. Adenosine-stimulated insulin biosynthesis was, however, unaffected by starvation.

Adenosine↗
PubMed1978

Cystosarcoma phyllodes in young women.

A total of eight cases of cystosarcoma phyllodes in women under 25 years of age were reported to the Swedish Cancer Registry during a ten-year period (1960 to 1969). Only one of these tumors was malignant. It was successfully treated with simple mastectomy and postoperative radiation therapy. Of the remaining seven cases, six were treated with local excision of the lesion and one with simple mastectomy. In no case, did the tumor recur during a follow-up of an average of ten years. Local excision seems to be sufficient for the benign form of the tumor, whereas simple mastectomy is indicated for the malignant form. Radical mastectomy is indicated only of the tumor has invaded the pectoral fascia. The tumor rarely metastasizes to the axillary lymph nodes.

Adolescent↗
PubMed1978

Isolated mouse pancreatic islets in culture: effects of serum and different culture media on the insulin production of the islets.

Various conditions for tissue culture of collangenase-isolated mouse pancreatic islets were studied in an attempt to optimize the maintenance of glucose stimulated insulin biosynthesis and release in the cultured specimens. Islets which had been cultured at a physiological glucose concentration (5.5 mmol/1) in the absence of serum had an impaired glucose-stimulated insulin biosynthesis and release as well as a reduced insulin content. Thus, insulin biosynthesis was three times higher after culture in a serum supplemented medium. Further, the insulin secretion of islets cultured in the presence of serum was markedly enhanced in acute incubations with high concentrations of glucose. This response was most pronounced in islets which had been cultured free-floating. A comparison between different culture media showed that islets cultured in RPMI 1640 had the highest insulin production. The present data suggest that the most favourable conditions for long-term storage of isolated islets in culture may be obtained when the islets are maintained as free-floating explants in a culture medium consisting of RPMI 1640 supplemented with serum.

Animals↗
PubMed1978

Insulin production by pancreatic islets of obese-hyperglycemic mice cultured for one week in different glucose concentrations.

Culture of pancreatic islets isolated from obese-hyperglycemic mice (gene symbol ob) for one week in media containing widely different concentrations of glucose (3.3, 5.6 or 16.7 mM) was found to markedly influence the functional behaviour of the islet B-cells. Thus, the insulin content of islets cultured at 3.3 or 16.7 mM glucose (subphysiological or supraphysiological glucose concentrations respectively) was markedly reduced. Islets cultured in 5.6 or 16.7 mM glucose displayed a normal insulin secretory response when stimulated with glucose, whereas islets cultured in a subnormal glucose concentration (3.3 mM) showed a reduced insulin response to glucose stimulation in batch type incubations and also lacked a second phase of insulin secretion in islet perifusion experiments. The rate of insulin biosynthesis of non-cultured ob/ob islets was higher than that of islets from their lean siblings but culture for one week in 3.3 mM glucose induced a pronounced impairment of the insulin biosynthesis in islets of obese as well as lean mice. The present data indicate that the hyperfunction of the islets of the ob/ob mouse at least in part is a reversible phenomenon, suggesting that inherent properties of islet B-cells do not act as "primary" factors in the development of the obese-hyperglycemic syndrome.

Animals↗
PubMed1978

Acute appendicitis in patients over sixty.

In an investigation of 68 consecutive patients over the 60 operated on for acute appendicitis in 1969--1972 the symptoms and signs did not differ notably from those in younger patients. However, the disease was more advanced in the elderly patients with perforation of the appendix in 49%. Postoperative complications occurred in about one third of the series, but were never fatal. Use of broad-spectrum antibiotics (ampicillin) is recommended. The investigation showed that it is possible to reduce the mortality from acute appendicitis in elderly patients to a level comparable to that in younger ones.

Acute Disease↗
PubMed1977

Effects of L-leucine on the insulin production, oxidative metabolism and mitochondrial ultrastructure of isolated mouse pancreatic islets in tissue culture.

This study was performed to evaluate whether L-leucine is able to relieve the structural and functional alterations previously described in pancreatic islets exposed in vitro for a prolonged time to a subnormal glucose concentration (3.3 mM). It was found that both the impairment of secretion and the decreased rate of biosynthesis of insulin characteristic of islets cultured for one week in 3.3 mM glucose were prevented by adding 15 mM L-leucine to the culture medium. Further more, the rates of tritiated water production and glucose or leucine oxidation were significantly enhanced after culture in the presence of L-leucine. The rate of DNA synthesis as estimated by the incorporation of tritiated thymidine was, however, unchanged by the presence of L-leucine in the culture medium. Leucine cultured islet cells displayed ultrastructural signs of high functional activity. A detailed morphometric examination revealed fewer but hypertrophic mitochondria. The present results suggest that L-leucine can replace glucose in several respects as a long-term stimulus of the pancreatic B-cells, possibly by acting as a metabolic substrate.

Animals↗
PubMed1977

Differentiation of acute hyperparathyroidism from severe hypercalcemia of malignancy.

Acute hyperparathyroidism should be distinguished from severe hypercalcemia of malignancy. In the former condition parathyroidectomy is often of vital importance; in the latter, the malignant neoplasm should be treated surgically or with radiation or cytostatics. The differential diagnosis is sometimes difficult because some patients with acute hyperparathyroidism have coexisting carcinoma elsewhere. Two patients subjected to parathyroidectomy because of severe hypercalcemia secondary to malignant neoplasms are described and compared with twelve similar cases from the literature. In patients with severe hypercalcemia medical treatment should always be tried first. If acute hyperparathyroidism cannot be excluded, subtotal parathyroidectomy should be performed after medical preparation.

Diagnosis, Differential↗