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Biomedical subjects

J F Hartmann

Publications and source records attributed to J F Hartmann.

At least 55 records · Page 3Linked to original sources
PubMed1974

Electron microscopic and chemical studies of the vascular changes and edema of lead encephalopathy. A comparative study of the human and experimental disease.

Lead encephalopathy was induced in suckling rats by administering lead to the mother. The brains were studied by light and electron microscopy, and the results were compared with observations in the human disease as well as in cases of cerebral ischemia in children. In their severe forms, both human and experimental lead encephalopathies are characterized by exudative extracellular edema and perivascular PAS-positive globules. The latter consist of osmiophilic non-membrane-limited cytoplasmic inclusions located, in the rat exclusively and in the human predominantly, in perivascular astrocytes. Intervascular strands are also found in both forms of the disease. In the rat these consist of basement membrane surrounding endothelial cytoplasm. Chemically, experimental lead encephalopathy with morphologically demonstrable edema is associated with an increase in brain water, sodium and serum albumin. Relative to the serum concentration, the increase in water is disproportionately greater than the sodium or albumin. There were no demonstrable changes in chloride or potassium.

Adult↗
PubMed1972

Early contact interactions between mammalian gametes in vitro: evidence that the vitellus influences adherence between sperm and zona pellucida.

A study in vitro of interactions between gametes of the golden hamster showed that the spermatozoon associates with the zona pellucida, or outer coat of the ovum, by two successive steps termed attachment and binding. Attachment, apparently the first step in fertilization, is not species-specific; it is insensitive to temperature (2 degrees ) and is reversible. Binding, on the other hand, is species-specific, temperature-sensitive, and irreversible. Experiments with isolated zonae pellucidae indicated that the vitellus (cellular portion of the ovum) influences the interaction between the sperm and the zona pellucida by increasing the time required for the sperm to bind. This effect is exerted on the sperm while they are attached to the zona pellucida.

Animals↗