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Biomedical subjects

K Federlin

Publications and source records attributed to K Federlin.

At least 91 records · Page 5Linked to original sources
PubMed1995

[Susceptibility to infections in diabetes--effects on metabolism].

Diabetic patients suffer from recurrent episodes of infections. The cellular and the humoral elements of the defense system against germ invasion are disturbed by the diabetic metabolism. Neuropathy and vascular damage promote the development of wounds and inhibit their healing. Altered motility of the gastrointestinal and the urinary tract lead to increased penetration of bacteria even there. Rare bacteria, atypical courses and frequent complications of infections result in delayed diagnosis and therapy. Dehydration, electrolyte disturbances, malnutrition, and reduced general conditions even increase susceptibility to an infection. On the other hand, an infection deteriorates the metabolic situation in diabetes, resulting in the need for higher insulin doses, or insulin injections in patients normally on oral medication. Altered every-day-life with modified food intake and reduced physical activity complicate diabetes therapy. Neuropathy, angiopathy, retinopathy, nephropathy and other diabetic complications can be triggered and aggravated during the course of an infection. To disrupt this vitious circle of hyperglycemia enforcing infections, which then raise blood glucose, it is necessary to know about the characteristic features of the interactions of diabetes and infection.

Bacterial Infections↗
PubMed1994

[Mexiletine in treatment of painful diabetic neuropathy].

The objective of this double-blind placebo controlled multicenter study was to prove the efficacy of mexiletine in painful diabetic neuropathy. Treatment was provided for in three dosages. For pain measurements a visual analogue scale (VAS) and McGill's verbal rating scale were chosen. 95 patients were included. A global assessment of the VAS showed no differences in treatment. The total evaluation (PRIT = Pain Rating Index Total) of the McGill scale just failed the level of significance. More specific exploratory evaluation of subclasses of the McGill scale, representing different qualities of pain, gave remarkable differences between mexiletine and placebo. According to types of complaints an evaluation showed substantial advantages of the mexiletine treatment with both the VAS and the McGill scale. There is strong evidence that particularly patients with stabbing or burning pain, heat sensations or formication will benefit most by mexiletine therapy. Concerning the dosage, a medium regimen of 450 mg per day seems to be appropriate in this indication. With an increase in dosage the efficacy does not rise proportionally. Mexiletine proved a very safe therapy with negligible side effects at the medium dose range, even less than placebo. There were no cardiovascular side effects. Further investigations should pay more attention to the variety of the complaints and include the quality of life.

Adult↗
PubMed1994

Production of purified alginates suitable for use in immunoisolated transplantation.

Alginate is used as a matrix for immunoisolation of cells and tissues in vivo. We have demonstrated previously that commercial alginates contain various fractions of mitogenic impurities and that they can be removed by free flow electrophoresis. The use of purified material is a necessity in order to reveal the parameters that control biocompatibility of the implanted material (such as stability, size, surface charge and curvature, etc.). In this study, we present a protocol for the chemical purification of alginates on a large-scale. Beads made from alginates purified by this multi-step chemical extraction procedure did not induce a significant foreign body reaction when implanted for 3 weeks either intraperitoneally or beneath the kidney capsule of Lewis or non-diabetic BB/Gi rats.

Alginates↗
PubMed1994

Intercellular adhesion molecule-1 (ICAM-1) expression in the islets of the non-obese diabetic and low-dose streptozocin-treated mouse.

The expression of intercellular adhesion molecule-1 (ICAM-1) was studied in 8-week-old non-obese diabetic (NOD) mice and low-dose streptozocin-treated (LDS) mice. ICAM-1 expression in NOD mice was observed at the islet periphery, corresponding to the peri-islet venular network, within the islet and on scattered elements along septa of the exocrine portion of the pancreas. Image analysis demonstrated that LDS-treated animals had less ICAM-1 immunoreactivity within and around the islets compared to NOD mice. At the ultrastructural level the peri-islet vessels were found to be filled with mononuclear elements. Moreover, endothelial cells showed signs of activation, and margination of monocytes and polymorphonuclear leukocytes was observed.

Animals↗
PubMed1994

Aminoguanidine inhibits the development of accelerated diabetic retinopathy in the spontaneous hypertensive rat.

Arterial hypertension has been identified as a major secondary risk factor for diabetic retinopathy. However, the mechanisms by which hypertension worsens retinopathy are unknown. Inhibition of advanced glycation product formation prevents the development of experimental diabetic retinopathy in normotensive diabetic rats. In this study the effect of hypertension on the rate of diabetic retinopathy development and the formation of arteriolar thrombosis was evaluated. We also evaluated the effect of aminoguanidine, an inhibitor of advanced glycation and product formation on retinal pathology of diabetic hypertensive rats. After 26 weeks of diabetes, hypertension accelerated the development of retinopathy despite a lower mean blood glucose level than in the non-hypertensive group (diabetic spontaneous hypertensive rats (SHR) 16.00 +/- 6.83 mmol/l; diabetic normotensive Wistar Kyoto rats (WKY) 34.9 +/- 3.64 mmol/l; p < 0.0001). Diabetic SHR had nearly twice as many acellular capillaries as diabetic WKY (SHR diabetic: 91.9 +/- 7.5 acellular capillaries per mm2 of retinal area vs WKY diabetic: 53.7 +/- 8.5 acellular capillaries per mm2 of retinal area), and a 3.8-fold increase in the number of arteriolar microthromboses (SHR diabetic 23,504 +/- 5523 microns2 vs SHR non-diabetic 6228 +/- 2707 microns2). Aminoguanidine treatment of SHR diabetic rats reduced the number of acellular capillaries by 50%, and completely prevented both arteriolar deposition of PAS-positive material and abnormal microthrombus formation. These data suggest that hypertension-induced deposition of glycated proteins in the retinal vasculature plays a central role in the acceleration of diabetic retinopathy by hypertension.

Aneurysm↗
PubMed1994

Enterostatin inhibits insulin secretion from isolated perifused rat islets.

The effect of enterostatin on glucose-induced insulin secretion was examined in isolated, perifused rat islets. In the presence of 16.67 mM glucose, there was significant inhibition of insulin secretion at concentrations of 200 nM, 2, 20 and 40 microM enterostatin. In particular, the second phase of insulin secretion was inhibited. With a low concentration of glucose (2.78 mM), there was no significant effect on insulin secretion by enterostatin. The inhibition of insulin secretion exerted by enterostatin may be an important effect in the prevention of insulin resistance.

Animals↗
PubMed1994

Effect of transplantation site and culture pretreatment on islet xenograft survival (rat to mouse) in experimental diabetes without immunosuppression of the host.

Recently, we reported on indefinite islet graft survival in allotransplantation (rat to rat). This was achievable without the use of any immunosuppression by performing transplantation of culture-pretreated (22 degrees C) islets of Langerhans under the renal capsule (r.c.) of chemically induced diabetic recipients. The aim of this study was to test this successful islet modulation technique in a xenogeneic animal model. Six groups of chemically induced diabetic, inbred, C57BL/6J mice received by transplantation either into the liver via the portal vein (i.po.) or under the renal capsule (r.c.) 300-350 either freshly or culture-pretreated (37 degrees C and 22 degrees C) Lewis rat islets without any immunosuppressive therapy. Histology was performed after rejection or post-transplant normoglycaemia (> 120 days) for evaluation of the graft. Transplantation of freshly isolated islets resulted in 75% graft rejection 17 days after transplantation. Using culture pretreatment at 37 degrees C, we noted 75% graft rejection 31 days after transplantation. In contrast, culture pretreatment at 22 degrees C resulted in a marked prolongation of xenograft survival, 75% graft rejection occurring 58 days after transplantation, and in two cases there was indefinite graft survival (> 120 days). Statistical analysis showed a significant prolongation of xenograft survival after culture pretreatment, with the most beneficial effect appearing after low-temperature culture at 22 degrees C (P < 0.05). Interestingly, xenograft survival was markedly prolonged only using the r.c. approach. Statistical comparison revealed a highly significant prolongation using the r.c. as transplantation site compared with i.po. (P < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

[Comparison of granulocyte function in diabetes mellitus type 1 and type 2].

The phagocytosis rate of polymorphonuclear leucocytes was measured by flow-cytometry. Vital bacteria were incubated in whole blood. 111 blood samples were measured, 54 in diabetic patients (14 type 1 and 40 type 2), the rest of 57 samples in healthy controls. Results showed firstly, that a decompensation in glucose metabolism in diabetic patients correlated with a decrease in phagocytosis. The HbA1 level was more closely correlated than the glucose level. The second result was, that despite a similar grade of decompensation in type 1 and type 2 diabetic patients, the phagocytosis was significantly lower in type 1 diabetes. No correlation was found concerning age and sex. These findings show, that the impact on granulocytic function in diabetes is of multifactorial origin, not only a shorter or longer elevation of the serum glucose level can explain it solely.

Adult↗