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M Ostenda

Publications and source records attributed to M Ostenda.

At least 19 recordsLinked to original sources
PubMed1981

Cerebral blood flow and ultrastructural studies of the brain capillaries in the early state of hypertension in SHR+.

The 133Xe single bolus injection technique was used for measuring the cerebral blood flow (CBF) in spontaneously hypertensive (SHR) and normotensive rats. Their age was from 5 to 25 weeks and corresponded to the time before the initiation of the arterial blood pressure (BP) increase to the constant phase of hypertension. CBF in SHR 5 and 10 weeks of age was significantly higher than in all other groups being 155 +/- 7.2 and 151 +/- 9.3 ml/min/100 g, respectively. At 15 weeks of age the localization of the reactive products of ATP and CTP became scanty and spread over the endothelial cytoplasm. Further, at 25 weeks an enlarged number of empty pinocytic vesicles and astrocytic foot processes filled with flocculent electron dense material was found. These data suggest that the initial high CBF preceding the increase of BP can initiate the irreversible disorder of endothelial cells in brain capillaries.

Animals↗
PubMedDate not supplied

The gliovascular interphase in irradiated brain tissue. Electron microscopic investigations on location of specific phosphatases.

In the brains of rats exposed to a dose of 800 rads of gammma radiation the location of phosphatases hydrolysing the following phosphate esters: adenosinetriphosphate (ATP), cytidinetriphosphate (CTP), guanosinetriphosphate (GTP) and inosinediphosphate (IDP) was determined in the ultramicroscopic structures. Changes were observed in their location in the gliovascular interphase. Early after the exposure (6 hours) the activity of specific phosphatases decreased in brain capillaries, then (48 hours) the reaction product disappeared from the basal membrane of the capillaries and appeared in the endothelium. Later (72 hours -- 7 days) the intensity of the reaction increased in the processes of the astrocytes adhering to the capillary. These changes took place concomitantly with an increase in the permeability of the blood-brain barrier and suggested that specific phosphatases participate in the barrier mechanisms.

Adenosine Triphosphate↗