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Biomedical subjects

H Yeger

Publications and source records attributed to H Yeger.

99 records · Page 6Linked to original sources
PubMed1977

A specimen carrier, storage disc system for scanning electron microscopy (SEM): evaluation of stainless steel as a substratum for cell culture in vitro.

A method of sample preparation for scanning electron microscopy (SEM) studies based on the use of stainless steel discs as a cell culture substratum is described in detail. A number of different cell lines were grown on stainless steel, and the growth patterns and biocompatibility of cells cultured on stainless steel were compared to identical cells cultured on aluminium, glass and plastic substrata. Stainless steel provides cells with an excellent growth surface which allows these cells to retain their normal growth characteristics and appearance. The non-toxic stainless steel discs can be manipulated through any combination of fixatives and organic solvents. The discs have been incorporated into a versatile system of sample preparation for SEM.

Alloys↗
PubMedDate not supplied

Enzymatic isolation of human trophoblast and culture on various substrates: comparison of first trimester with term trophoblast.

A simple method is described for the isolation of trophoblast cells from both first trimester and term placenta. Trophoblast preparations were characterized by light microscopy, scanning and transmission election miscroscopy and immunohistochemistry to distinguish these cells from mesenchyme and endothelium. Trophoblast cells were cultured on various substrates and a comparison made of their ability to attach, proliferate and function. A collagen gel substrate produced by repolymerization of an acid soluble collagen fraction from chorionic villi allowed rapid attachment of trophoblast cells and maintainance of their original morphology. Term trophoblast cells were shown to become fully functional in short term (three day) cultures by virtue of their increased immunocytochemical staining for the presence of beta hCG, hPL and SPI. beta hCG increased significantly by day three thus demonstrating functional activation. Trophoblast cells from first trimester placenta formed proliferating colonies of hormone producing cells while those from term placenta reaggregated into clusters and closely resembled syncytiotrophoblast both morphologically and functionally. This short term culture system for term trophoblast will allow further studies into the biology of trophoblast polypeptide hormone synthesis and secretion.

Cell Separation↗
PubMedDate not supplied

Abnormalities of cilia in the middle ear in chronic otitis media.

We studied the fine structure of nasal and middle ear mucosa in 18 patients with chronic otitis media, comparing them with ten age-matched control patients. Electron microscopy revealed no single fundamental defect of cilia in the tissue samples; however, patients with chronic otitis media had a significantly higher incidence of abnormal cilia in the middle ear without correlating abnormalities of nasal cilia. These findings indicated that ciliary anomalies, including deletion of ciliary microtubules, presence of supernumerary tubules, and fusion of cilia, occur as a result of infection or inflammation. Such abnormalities would impair normal mucociliary clearance and exacerbate clinical complications.

Adult↗
PubMedDate not supplied

Acellular matrix allograft small caliber vascular prostheses.

We have developed an acellular matrix vascular prosthesis (AMVP) made by detergent and enzymatic extraction of natural arteries, yielding a tissue framework of collagen and elastin from the original vessel, with preservation of the natural basement membrane at the blood flow surface. These biografts have excellent handling characteristics and suturability, as well as low thromboreactivity. Whole vessel static testing of circumferential compliance (8.9 +/- 1 [SEM] X 10(-2)% mmHg at 100 mmHg) revealed behavior virtually identical to the paired natural vessel from which each AMVP was derived in nine canine carotid arteries. We implanted 16 canine-origin AMVPs into nine dogs (12 femoral and three carotid arteries, and one infrarenal aorta) with no antithrombotic drugs. Angiographic patency was maintained in 15 of 16 (one occlusion within 3 days) for follow-up from 3 days to 6 years, with no aneurysm formation in three AMVP at over 4 1/2 years. Explant analysis revealed preservation of AMVP elastica and collagen with no inflammation or dystropic calcification of the AMVP, and almost total thrombus free flow surfaces. These results suggest that allograft AMVPs could achieve long-term patency equivalent to saphenous veins.

Animals↗