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Biomedical subjects

E P BENDITT

Publications and source records attributed to E P BENDITT.

At least 37 records · Page 2Linked to original sources
PubMed1961

Wound healing and collagen formation. I. Sequential changes in components of guinea pig skin wounds observed in the electron microscope.

The regular sequence encountered in healing guinea pig skin wounds has been examined by methods of light and electron microscopy. Observations on cell populations, their fine structure, and fibril formation in the connective tissue have been made. Linear incisions in the skin of normal female guinea pigs weighing 300 to 350 grams were allowed to heal. The wounds were then excised, fixed with buffered 2 per cent osmium tetroxide, and postfixed in neutral buffered formalin, at 16 and 24 hours and at 3, 5, 9, and 14 days after wounding. They were then embedded in epoxy resin. In the inflammatory phase the exudate observed in the early wounds consists largely of polymorphonuclear neutrophilic leukocytes, macrophages, fibrin, and free extracellular organelles from the disrupted inflammatory cells. These organelles later appear in vacuoles in the cytoplasm of the macrophages. Fibroblasts first appear at 24 hours, and show extensive development and dilatation of the endoplasmic reticulum, which sometimes contains moderately dense flocculent material. In addition, these fibroblasts have enlarged mitochondria and condensations of filamentous material within the cytoplasm near the cell surface. Occasional myelin figures and moderately dense, 0.5 to 1.0 micron bodies are found within the cytoplasm of the early fibroblasts. Collagen fibrils are first seen at 3 days extracellularly near the cell surfaces. They appear at the later times in two populations of sizes. With increasing wound age the fibroblasts retain their morphology and the wounds decrease in cellularity concomitantly with the formation of increasing amounts of collagen. Several proposed mechanisms of collagen fibril formation are discussed in relation to the observed phenomena. The problem of correlating fibril diameter with the appearance of the periodic structure of collagen in relation to the minimal size fibril which would be anticipated to display this appearance is discussed.

Animals↗
PubMed1960

Mast cell degranulation and histamine release observed in a new in vitro system.

A method is described by which mast cells harvested from the rat peritoneal cavity can be deposited on the surface of a Millipore filter without gross injury, permitting observation of morphological and chemical changes induced by a variety of agents. These isolated peritoneal mast cells respond to 48/80 and to polymyxin B but not to dextran or ovomucoid with degranulation and histamine release. Thus four agents which in vivo appear to have similar activities have been found by means of in vitro analysis to operate by at least two different mechanisms.

Animals↗
PubMed1960

Estradiol reduces incorporation of radioactive sulfate into cartilage and aortas of rats.

Estradiol in large amounts reduces the incorporation of radioactive sulfate into cartilage and aortas of rats. This reduction becomes apparent within 3 days for cartilage and 3 weeks for aorta. The effect is not mediated through suppression of testosterone secretion and the hypophysis is not necessary for the effect to be demonstrated. The thoracic segment of aortas from normal rats incorporates more sulfate than does the abdominal segment and this difference is reduced following the administration of estradiol.

Animals↗
PubMed1959

An enzyme in mast cells with properties like chymotrypsin.

Mast cells contain an enzyme which hydrolyzes 3-chloroacetoxy-2-naphthoic acid anilide. By using highly purified mast cells isolated by differential centrifugation in high density sucrose solutions we have been able to study this enzymatic activity in more detail. The enzyme has properties similar to those of chymotrypsin: Chymotrypsin will hydrolyze the histochemical substrate, and the chymotrypsin and mast cell activities with this substrate are similarly inhibited by diisopropylfluorophosphate. The mast cell enzyme is capable of hydrolyzing the N-acetyl esters of tryptophan, tyrosine, and phenylalanine, the relative rates of hydrolysis being similar to those seen with chymotrypsin. A characteristic trypsin substrate, p-toluenesulfonyl arginine methyl ester, is not acted upon by the mast cell enzyme or chymotrypsin. The pH activity curve of the new cell enzyme is similar to that of chymotrypsin as determined with N-acetyl-L-tryptophan ethyl ester as substrate.

Chymotrypsin↗