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Biomedical subjects

P A Stagno

Publications and source records attributed to P A Stagno.

5 recordsLinked to original sources
PubMed1987

Strumal carcinoids of the ovary. An immunohistologic and ultrastructural study.

A series of six ovarian strumal carcinoids was examined. The presence of thyroid follicular epithelium was conclusively proved by the presence of follicular cells immunohistochemically positive for thyroglobulin, and by the ultrastructural identification of non-neuroendocrine cells with features of thyroid epithelium lining the follicles. Progressive replacement of thyroid epithelial cells by carcinoid cells accounts for the predominance of neuroendocrine granule-containing cells and the scarcity of thyroid epithelial cells lining many of the follicles. A variety of neuroendocrine hormones and other immunoreactive substances was demonstrated within carcinoid cells, including somatostatin (five cases), chromogranin (five cases), serotonin (five cases), glucagon (four cases), insulin (two cases), and gastrin (one case). Only one case contained calcitonin-positive cells. None were carcinoembryonic antigen-positive or had amyloid deposits. The carcinoid element in five cases stained positively for prostatic acid phosphatase. While strumal carcinoid shares some features with medullary carcinoma of the thyroid gland, it has sufficient differences to warrant a separate designation.

Acid Phosphatase↗
PubMed1980

A silver method for staining normal axis cylinders of central nervous system structures.

The fink-Heimer stain for degenerating axons has been modified for demonstration of normal axis cylinders. The technique stains tissue prepared from a variety of fixation protocols. Vibratome prepared sections, coupled with an efficient use of laboratory time makes this procedure a simple, quick, and repeatable general technique. This preparation provides valuable insight into the histological organization of the intact central nervous system.

Animals↗
PubMed1978

Effects of cytochalasin B on the fine structure of organized endodermal cells of the early chick embryo.

Fresh pullet eggs (White Leghorn) were incubated for 36 to 48 hours. The blastoderms were exposed to cytochalasin B (CB), 10 or 40 microgram/ml, for 2, 5, and 15 minutes prior to fixation by immersion in buffered chick Ringers solution containing CB, previously dissolved in dimethysulfoxide (DMSO), or by sub-blastodermic injection. Controls fixed in ovo possess relatively flat surfaces with bulges due to uptake of yolk. Numerous microappendages (blebs, microvilli and ruffles) are present, especially at cell margins. DMSO-controls present a similar cell surface except that small blebs are more prominent. The plasmalemmas of CB-treated endodermal cells possess numerous large blebs (2-10 micron in diameter), smaller blebs (0.2 micron) and microvilli. Cell dissociation occurs in selected areas resulting in rounded cells, devoid of microappendages, with peripheral processes. Transmission electron microscopic preparations of tissues similar to those used for scanning electron microscopy reveal that large blebs are filled with membranous material. Microfilaments are present but lack their normal subplasmalemmal arrangement. Microtubules and other cell organelles are apparently unaffected by CB. Evidence in this study supports the concept that cytochalasin B exerts its influence through alteration of the plasmalemma.

Animals↗
PubMed1976

Lactate dehydrogenase changes following several cardiac hypertrophic stresses.

The effects of four different cardiac hypertrophic stresses on cardiac lactate dehydrogenase (LDH) isozyme composition and activity were examined. Altitude-induced right ventricular hypertrophy was accompanied by an increase of 10% in the M subunit of LDH in right ventricle, left ventricle, and atria. Left ventricular hypertrophy induced by aortic stenosis also produced isozyme changes in the ventricles, but of only half the magnitude. Biventricular hypertrophy, induced by running or swimming, was accompanied by 4-5% increases in M LDH in the ventricles only. We conclude that changes in LDH activity are directly related to changes in the M subunit in all three portions of the heart. No changes in H subunit were noted under any of the stresses. It appears that the magnitude of changes in cardiac LDH isozyme composition are only marginally related to extent of hypertrophy.

Altitude↗