Biomedical subjects

S Pettersen

Publications and source records attributed to S Pettersen.

4 recordsLinked to original sources

PubMed1992

Effects of hypothermia and rewarming on phospholipase C-evoked glycerol output in rat myocardial cells.

The combined action of phosphatidylcholine preferring phospholipase C (PC-PLC) and intracellular lipases has recently been shown to cause glycerol output in energy deprived rat cardiomyocytes. In the present study we examined the effect of hypothermia and rewarming on PC-PLC evoked glycerol output in freshly isolated, calcium-tolerant myocytes. The cells were preincubated for 60 min at hypothermic (5 degrees C) or normothermic (37 degrees C) conditions in Krebs-Henseleit bicarbonate buffer (pH 7.4) supplemented with 1 mM DL-carnitine, 1% B.S.A. and 5 mM glucose. Addition of PC-PLC resulted in a significantly higher (P less than 0.05) output of glycerol in myocytes undergoing rewarming than in myocytes kept constantly at 5 degrees C or 37 degrees C. The values obtained for PC-PLC induced glycerol output (difference in glycerol output between incubations with and without PC-PLC) were 6.77 +/- 2.6 (37 degrees C), 4.54 +/- 1.7 (5 degrees C) and 22.85 +/- 5.9 (5-37 degrees C) nmol/10(6) cells.h. Rewarming in addition caused a significantly higher (P less than 0.05) leakage of lactate dehydrogenase (LDH) from the rewarmed cells as compared to cells at constant temperatures (5 degrees C or 37 degrees C). However, there was no additional effect of PC-PLC on LDH leakage. The elevated PC-PLC induced glycerol output in rewarmed myocytes was not related to a fall in the percentage of rod-shaped cells or a reduced cellular content of ATP, since no differences could be detected between the various myocyte preparations with respect to these parameters.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphate↗

PubMed1990

Cerebral capillary bed structure of normotensive and chronically hypertensive rats.

In this study cerebral capillary bed structure and the effects of chronic hypertension on these systems have been assessed in 6- to 7-month-old spontaneously hypertensive (SHR) and Wistar-Kyoto (WKY) rats. Capillary diameter (D), profile frequency (Na), volume fraction (Vv), and surface area (Sv) were quantitated by light microscopic morphometry of eight brain areas including the sensorimotor cortex and subfornical organ. Previously presented data from normotensive Sprague-Dawley rats (SpD) of similar age were also compared. Within each of the three rat strains, D, Na, Vv, and Sv varied among brain areas. For the sensorimotor cortex and subfornical organ, capillary profile frequency differed significantly among the three rat strains. In SHR and WKY, there was an inverse correlation between profile frequency and diameter, i.e., as Na increased among brain areas, D decreased. In six brain areas capillary volume fraction and surface area were identical in SHR and WKY, but were lower in SpD. Consistent differences between SHR and WKY were found only for the subfornical organ, which suggests some involvement of this structure in hypertension. Since there were few statistically significant differences between SHR and WKY and many statistically significant differences between the two normotensive strains, cerebral capillary bed structure seems to be independent of arterial blood pressure in most brain areas of these rats.

Animals↗

PubMed1989

Electrophoretic study of proteins associated with pseudo-exfoliation syndrome.

Lens capsule and aqueous humour from cataractous eyes with and without pseudo-exfoliation syndrome have been studied by SDS-PAGE electrophoresis. Four cataractous lenses with and four without pseudo-exfoliation were used. The pseudo-exfoliation positive capsule revealed two polypeptides not present in the control material, and accordingly, these components were regarded to be pseudo-exfoliation specific. The molecular weight of the respective polypeptides was estimated to be 14,400 and 16,300. No marked differences were found between the pseudo-exfoliation positive and negative aqueous humours.

Aqueous Humor↗

PubMed1988

Structural and functional variations in capillary systems within the brain.

The major hypothesis of this study is that there are differences among brain areas in capillary bed structure and function. Three general differences between circumventricular organ and non-CVO capillary beds were found. First, the PS products for AIB were about 300 times greater in CVO capillaries than in non-CVO (blood-brain barrier) capillaries. Second, the frequency of endothelial cell fenestrations was much greater in CVO capillaries than in non-CVO capillaries and the fenestrae may be structural modifications of endothelial cells that permit ready passage of solutes such as AIB. Third, the frequency of mitochondria was greater in BBB capillaries than in CVO capillaries; this high metabolic potential of BBB capillaries may be associated, in part, with "carrier-mediated" transport of various solutes between plasma and cerebral interstitial fluid. Capillary bed differences among all (i.e., both CVO and non-CVO) brain structures were also observed. Among these differences are: rate of blood flow, mean transit time of albumin, capillary volume and surface area, perfused microvessel blood volume, apparent percentage of perfused capillaries, PS products for AIB, and frequency within the endothelium of vesicular profiles.

Aminoisobutyric Acids↗