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Biomedical subjects

A Petter

Publications and source records attributed to A Petter.

45 records · Page 3Linked to original sources
PubMedDate not supplied

Senile plaques and neurofibrillary changes in the brain of an aged lemurian primate, Microcebus murinus.

In some aged Microcebus brains (8- to 11-year-old animals) dramatic atrophy is found, particularly of the cortex, the hippocampus, the basal ganglia, the brainstem and the cerebellum, associated with a conspicuous increase in the size of the cerebral ventricles. These morphological changes are accompanied by certain histological profiles indicative of pathology. In the cortex, these histological changes consist of 1) a large number of senile plaques composed of degenerated neurites sometimes surrounding an amyloid plaque, 2) amyloid deposits in the vascular walls and 3) dense bundles of argyrophilic filaments in numerous pyramidal neurons. All these lesions resemble changes associated with Alzheimer's disease in man. The degenerative changes observed in the Microcebus brain are accompanied by behavioral changes. At the moment these preliminary studies, carried out on the smallest of all primates, do not prove that the degeneration is of the Alzheimer type, but do indicate that Microcebus murinus may well be a good model for the study of cerebral aging, providing a comparison with cerebral ageing in humans. The size, life span and cost of the animal provide further advantages when compared with other nonhuman primates.

Amyloid↗
PubMedDate not supplied

Choline acetyltransferase and somatostatin levels in aged Microcebus murinus brain.

beta-Amyloid protein (beta-AP) deposits, analoguous to those found in Alzheimer's disease (AD) are observed in the brain of aging Microcebus murinus. Because choline acetyltransferase (ChAT) activity and somatostatin (SRIH) content are consistently decreased in AD, we tested whether such changes could be observed in middle aged to aged Microcebus cerebral cortex and whether they were accompanied by beta-AP deposits. A positive correlation was observed between age and ChAT activity. By HPLC, SRIH immunoreactivity eluted as four peaks, two of which being identical with SRIH-28 and SRIH-14 while the other two likely represented precursor forms. Cortical SRIH content was not significantly affected by age. ChAT activity and SRIH content were not significantly correlated. Amyloid angiopathy was observed in every brain examined and the presence of cortical lesions analoguous to senile plaques observed in the oldest case only which did not demonstrate important alterations in ChAT and somatostatin levels.

Aging↗
PubMedDate not supplied

Identification of amyloid beta protein in the brain of the small, short-lived lemurian primate Microcebus murinus.

The deposition of amyloid beta (A beta) protein in the brain has been demonstrated immunocytochemically in the small Lemurian primate Microcebus murinus. Both meningocerebral vascular deposits and cortical parenchymal deposits occur. All eight aged (> 8 years old) Microcebus examined showed vascular amyloid deposits, whereas only four exhibited parenchymal plaques. The vascular amyloid infiltrated the tunica media of the leptomeningeal and cortical arteries and arterioles and was also found in capillaries. A beta was observed to be deposited in three general forms in the cortical neuropil: round or elliptical plaques that were thioflavin-negative but sometimes showed a central concentration of A beta immunoreactivity; round plaques with a densely immunoreactive core that was thioflavin-positive; extensive ribbon-like infiltrations enclosing multiple cortical blood vessels. These observations, taken together with previous descriptions of age-related neurodegenerative changes in Microcebus, indicate that this species undergoes a beta-amyloid-associated neuropathology highly similar to that seen in Alzheimer's disease. We conclude that this lemurian primate of small size and relatively short life expectancy, provides a compelling animal model of some principal features of Alzheimer's disease.

Aging↗
PubMedDate not supplied

[Do the eosinophilic granulomas observed in Brittany represent a form of anisakiasis? The larvae of Thynnascaris aduncum do not produce these granulomas experimentally].

To explain the enigmatical origin of gastric eosinophilic granulomas prevailing among patients in Brittany (France), we have tried to experiment with the larvae of Thynnascaris (Thynnascaris aduncum (Rud.)), a Nematode found in the sardine (Sardina pilchardus (Walbaum)), a fish sometimes eaten raw in our country. In a preliminary experiment, larvae of Thynnascaris were observed to penetrate the mucosa of the rabbit stomach in vitro at room temperature. But in vivo, whatever the means, the ways and the experimented mammals of our study, we have failed to experimentally reproduce such tumours. We think that this result belongs to the fact that the larvae of Thynnascaris in the conditions of our experimentation could not perform an evolution in homeothermal animals.

Animals↗