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Biomedical subjects

K Blomgren

Publications and source records attributed to K Blomgren.

43 records · Page 3Linked to original sources

Calpain and calpastatin levels in different organs of the rabbit.

1. The levels of Ca-independent and Ca-dependent proteolytic activity as well as the activities of calpains and calpastatin in different organs of the rabbit was examined at various developmental stages. 2. Calpain and calpastatin levels were highest in the lung and in the kidney. 3. In all organs examined except the thymus the total level of calpain was higher than that of calpastatin. 4. In the thymus the levels of calpains and calpastatin decreased markedly with age.

Aging↗

A possible physiological role of the Ca-dependent protease calpain and its inhibitor calpastatin on the Ca current in guinea pig myocytes.

The decrease ('run-down') of the L-type Ca2+-current during long-lasting recordings with the whole-cell patch-clamp technique was examined in guinea pig ventricular myocytes. We have tested whether proteolysis is involved in the decay of the Ca2+-current by intracellular application of several concentrations of the Ca2+-dependent proteases calpain I and II, as well as their endogenous inhibitor calpastatin. The major finding was that calpain I and calpain II accelerated the Ca2+-current run-down in a concentration dependent manner, whereas calpastatin retarded it. These observations indicate that a proteolytic degradation of Ca2+-channels might be the reason for the run-down phenomenon.

Animals↗

Calpain and calpastatin in normal and Alzheimer-degenerated human brain tissue.

The Ca2(+)-dependent neutral proteases calpain I and II as well as their specific inhibitor, calpastatin, were isolated from normal and Alzheimer-degenerated frozen human brain tissue. In the Alzheimer group calpain I activity was higher in cortex than in mesencephalon. The calpastatin activity was lower in cortex in both groups. This may implicate a higher Ca2(+)-dependent proteolysis in cortex compared to mesencephalon. In the Alzheimer group the cortical calpain II level decreased with an increasing degree of neuropathological changes. In the control group, the level of calpastatin decreased as the number of plaques and tangles increased. Evidence was obtained for a correlation of net calpain activity and the extent of neuropathological changes in cortex.

Aged↗

Increased proteolytic activity in lymphocytes from patients with early onset Alzheimer's disease.

The levels of calpains (m-calpain and mu-calpain) in peripheral blood lymphocytes from patients with Alzheimer's disease were determined via Western blotting. The Ca-dependent proteolytic activity and the calpastatin activity were estimated using incubation with exogenous substrate. Evidence was obtained for an increased Ca-dependent proteolytic activity in lymphocytes from patients with early onset Alzheimer's disease. There was also an increased level of membrane-bound mu-calpain in this group of patients. The observed changes may be caused by a general dysregulation of Ca homeostasis in peripheral cells of early onset Alzheimer victims.

Age of Onset↗

Transplantation of preconditioned intestinal grafts is associated with lower inflammatory activation and remote organ injury in rats.

Reperfused grafts--particularly the intestine--release free radicals and cytokines into the systemic circulation. The type of discharge, which is greatly dependent on the local injury, may also induce inflammatory activation in distant organs and leading to multiple system and organ failure. It has been suggested that intestinal grafts from tacrolimus (TRL)-pretreated donors show improved morphology and microcirculation. We studied whether transplantation of intestines from TRL-pretreated donors influenced inflammatory response and remote organ injury posttransplantation. Donor Sprague Dawley rats received TRL or saline (controls) intravenously at 6 hours prior to graft harvest. The intestinal grafts were preserved in saline for 3 hours before transplantation. At 6 and 12 hours postreperfusion hepatic and renal cortical microcirculation were assessed using laser-Doppler flowmetry (n = 8-12 per group). Blood pressure was measured; liver, kidney, and serum samples were obtained. We analyzed hepatic and renal ICAM-1 expression and caspase-3-like activity as well as plasma content of tumor necrosis factor-alpha and interleukin-6. Pretreated graft recipients had higher mean arterial pressure (82 +/- 10 vs 51 +/- 17 mm Hg, P < .05) and renal perfusion at 6 hours whereas liver perfusion was similar at both 6 and 12 hours. Liver and renal functions were also superior among recipients of pretreated grafts. Both caspase-3-like activity and ICAM-1 expression in liver and kidney were lower in pretreated graft recipients. Plasma IL-6 levels were lower in animals receiving pretreated grafts. Transplantation of intestines from TRL-pretreated donors was followed by a lower systemic inflammatory response, improved organ function and decreased remote injury early posttransplantation compared with animals receiving grafts from untreated donors.

Animals↗