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F Cahn

Publications and source records attributed to F Cahn.

9 recordsLinked to original sources
PubMed1997

Infrared spectroscopy of normal and abnormal cervical smears: evaluation by principal component analysis.

Fourier-transform infrared (FT-IR) spectra of malignant and dysplastic cervical scrapings were abnormal, as first described in our study of a limited number of samples, where the spectra were evaluated by visual inspection and peak intensity ratios. We have expanded our study to evaluate more cervical conditions, and to analyze the spectra by a chemometric approach (principal component analysis [PCA]). Cervical samples from 436 females were evaluated by FT-IR and Papanicolaou testing; 40/436 spectra were nonanalyzable. The remaining were as follows: normal, 174; malignant, 19; dysplasia, 8; atypia, 113; atrophy, 19; inflammatory, 47; bloody smear, 12; hypocellular, 4. PCA analysis followed by chi2 test revealed that statistically significant frequencies of being predicted malignant by FT-IR were associated with samples diagnosed as malignant (P < 0.0001), and also those diagnosed as "atrophy" (P < 0.001), "atypical with bloody smear" (P < 0.05), "atypical with atrophic pattern" (P < 0.05), and "dysplasia" (P < 0.05). Based on these findings, for the diagnosis of cervical cancer by FT-IR, as defined here, the sensitivity is 79%, the specificity is 77%, the positive predictive value is 15%, and the negative predictive value is 98.6%. Our findings (a) demonstrate the application of a chemometric approach to the study of cervical FT-IR spectra; (b) assess its potential diagnostic role; (c) suggest that atrophic and neoplastic samples share structural features; and (d) suggest that blood may interfere with such spectroscopic evaluation. These findings warrant further evaluation of FT- IR spectroscopy in cervical and other malignancies.

Cervix Uteri↗
PubMed1991

Assessment of cell proliferation on porous microcarriers by means of image analysis.

Spherical porous microcarriers (PMCs) made from collagen-glycosaminoglycan crosslinked copolymers have exhibited considerable promise as growth surfaces for the proliferation of anchorage-dependent mammalian cell lines and have demonstrated the ability to entrap anchorage-independent cells. However, quantification of cell growth on PMCs has proved difficult. A method of measuring the proliferation of PMCs, based on image analysis, is presented. Using CV1 and CHO cell lines, samples of PMCs were removed from culture at various times, fixed, embedded and sectioned. The 2 microns sections were stained, photographed and digitized in three colors. A computer program was developed to evaluate digitized PMC cross-sections and to classify pixels as conforming to either background, cytoplasmic, matrix or nuclear parameters, based on a set of classification rules determined by statistical analysis. Growth curves were generated by relating the number of pixels occupied by cellular material to the total number of pixels in the PMC cross-section. The PMCs were found to foster cell proliferation, with cell densities approaching 100% occupancy.

Animals↗
PubMed1990

Biomaterials aspects of porous microcarriers for animal cell culture.

Porous microcarriers are new support materials with important advantages in both industrial cell-culture processes and the culture of cells of medical importance. Porous microcarriers are now commercially available with internal architecture and surface chemistry suitable for culture of both anchorage-dependent and anchorage-independent animal cells.

Animals↗
PubMed1982

Amiloride, protein synthesis, and activation of quiescent cells.

Amiloride is known to inhibit both influx of sodium ions and activation of quiescent cells by growth factors. The coincidence of these effects has been cited to support the proposal that influx of sodium ions acts as a mitogenic signal. Although it was noted that amiloride inhibited protein synthesis, this was attributed to an action on transport of amino acids, particularly those coupled to sodium fluxes. We find, however, that amiloride directly inhibits polypeptide synthesis in a reticulocyte lysate. In Swiss 3T3 cells, concentrations of amiloride and of cycloheximide that are nearly matched in their degree of inhibition of protein synthesis, produce about the same degree of inhibition of transit of cells from G0 to S. Inhibition of protein synthesis is sufficient to explain the effect of amiloride on mitogenesis; the drug, therefore, is not suitable for testing the hypothesis that sodium influx is a mitogenic signal.

Amiloride↗
PubMed1978

Inhibition of elongation steps of protein synthesis at reduced potassium concentrations in reticulocytes and reticulocyte lysate.

We treated intact reticulocytes with nystatin to make them permeable to small cations and varied the concentration of K+ in the medium; the ionic strength was kept constant by adjusting Na+. As the intracellular K+ was lowered, the rate of protein synthesis decreased. In a reticulocyte lysate, the dependence of the rate of protein synthesis on K+ concentration (at constant ionic strength) was similar to that seen in nystatin-treated cells. We observed no loss of polysomes at low K+. Even when initiation was blocked with aurintricarboxylic acid, decreased K+ inhibited protein synthesis. Analysis of the kinetics of synthesis showed that lowering the K+ concentration inhibits the rate of elongation of nascent chains, but has little effect on the relative rate of initiation of chains.

Animals↗
PubMedDate not supplied

Permeable collagen-glycosaminoglycan cross-linked copolymers for the study of biological responses of cocultured Sertoli and spermatogenic cells.

A novel collagen-glycosaminoglycan (C-GAG) substrate was developed to overcome the optical opacity of a HATF nitrocellulose substrate and to provide a more physiological permeable substrate for cocultured Sertoli and spermatogenic cells. Cocultures were prepared on optically transparent C-GAG discs attached to a polyester mesh to facilitate handling. Sertoli cells displayed a cuboidal-to-columnar shape; a large number of spermatogonia and primary spermatocytes connected by intercellular bridges were associated with basolateral and apical surfaces of Sertoli cells up to 12 days after plating. Rat Sertoli-spermatogenic cell cocultures have been used for testing the effect of toxicants on rat spermatogenesis in vitro. In our initial studies, we tested the effects of the toxicant gossypol on spermatogenic cells cocultured with Sertoli cells on non-permeable (plastic) and permeable substrates (HATF nitrocellulose) under both standard culture conditions and during perifusion after achieving a continuous electrical-resistant cell monolayer. A selective mitochondrial structural damage was observed in spermatogenic cells (spermatogonia and spermatocytes) but not in the coexisting Sertoli cells. This damage was time- (15-60 min) and dose-dependent (0.1-10 microM) and developed more rapidly under perifusion conditions. Similar mitochondrial damage was reported in the intact animal but required higher concentrations (mg) and longer administration time (months) for detection. Studies are in progress to evaluate the effect of additional toxic chemical agents on functional properties of Sertoli and spermatogenic cells in cocultures prepared on various classes of C-GAG substrates.

Animals↗