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Biomedical subjects

C H Fox

Publications and source records attributed to C H Fox.

At least 109 records · Page 6Linked to original sources
PubMed1979

Quantitative reflection contrast microscopy of living cells.

Mammalian cells in culture (BHK-21, PtK2, Friend, human flia, and glioma cells) have been observed by reflection contrast microscopy. Images of cells photographed at two different wavelengths (546 and 436 nm) or at two different angles of incidence allowed discrimination between reflected light and light that was both reflected and modulated by interference. Interference is involved when a change in reflected intensity (relative to glass/medium background reflected intensity) occurs on changing either the illumination wavelength or the reflection incidence angle. In cases where interference occurs, refractive indices can be determined at points where the optical path difference is known, by solving the given interference equation. Where cells are at least 50 nm distant from the glass substrate, intensities are also influenced by that distance as well as by the light's angle of incidence and wavelength. The reflected intensity at the glass/medium interface is used as a standard in calculating the refractive index of the cortical cytoplasm. Refractive indices were found to be higher (1.38--1.40) at points of focal contact, where stress fibers terminate, than in areas of close contact (1.354--1.368). In areas of the cortical cytoplasm, between focal contacts, not adherent to the glass substrate, refractive indices between 1.353 and 1.368 were found. This was thought to result from a microfilamentous network within the cortical cytoplasm. Intimate attachment of cells to their substrate is assumed to be characterized by a lack of an intermediate layer of culture medium.

Animals↗
PubMed1979

Viability of the cervical epithelium during carcinogenesis in mice.

Autoradiograms of histological specimens from the cervix of seventy-five mice were analysed after in vivo injection with an RNA precursor. All nucleated, non-pyknotic cells and some mitotic figures were labelled, which suggested that the tissue was metabolically active (i.e. viable). Only the uppermost epithelial pyknotic cells were devitalized, as deduced by the morphological appearance of the cells and by the absence of label. The viability of the whole epithelium suggests that the previously reported focal distribution of proliferating and non-proliferating areas in the cervical epithelium of mice is a genuine phenomenon.

Animals↗
PubMed1979

Effect of various routine cytopreparatory techniques on normal urothelial cells and their nuclei.

Nuclear and cytoplasmic sizes of cells in permanent, stained smear preparations differ from those in unfixed unstained cells. In air-dried MGG-stained smears the area of the nucleus is 50% larger and that of the cytoplasm 30% larger. In wet-fixed Papanicolaou-stained smears the nucleus is 10--30% and the cytoplasm is 15--55% smaller. The shrinkage in the wet fixation method is dependent on the concentration of the ethyl alcohol applied. The staining method has relatively little influence on nuclear and cytoplasmic size. The three-dimensional appearance of the smeared, stained cells is also dependent on the cytopreparatory technique applied:in the methods with air-drying the nuclei and cells are flat and in the wet fixation method more spherical. In the methods with air-drying the nuclear:cytoplasmic ratio is larger than that seen with the wet fixation methods.

Cell Nucleus↗
PubMed1979

Inhibitory effect of the antioxidant butylated hydroxyanisole on the activation of the carcinogen benzo(a)pyrene.

The effect of the antioxidant butylated hydroxyanisole (BHA) on benzo(a)pyrene (BP) metabolites binding to DNA, percentage of diols and phenols in the total amount of BP metabolites extracted to organic solvent, were studied in : incubation mixture of rat liver microsomes, cultured mouse embryo cells, human skin, and human lymphocytes. The amount of BP metabolites bound to DNA in mouse embryo cells and human skin decreased in the presence of BHA. No effect was found in human lymphocytes. Percent of phenols increased in mouse embryo cell cultures; percent of diols decreased in cultures of human skin and lymphocytes.

Animals↗
PubMed1978

Adnexal malignancy detected by cervical cytology.

These case presentations are submitted to focus attention on positive (Class V) cervicovaginal cytologic results compatible with adenocarcinoma in the face of benign endocervical and endometrial tissue and in the absence of clinically detectable adnexal disease. Two patients were found to have primary ovarian malignancy, and one patient had adenocarcinoma of the distal end of the right Fallopian tube. Provided that there is confidence in the cytologic diagnosis and that primary disease has been ruled out elsewhere, the clinician is encouraged to utilize additional diagnostic methods, such as laparoscopic visualization of the pelvis and peritoneal fluid studies, in an attempt to facilitate early diagnosis of nonpalpable adnexal disease.

Adenocarcinoma↗
PubMed1978

A simple and inexpensive culture device for cell growth, quantitative microscopy and autoradiography.

An inexpensive culture chamber suitable for subsequent preparations for cytochemical or radiographic work is demonstrated. The chamber consists of two glass microscope slides suitably prepared for cell growth and a gasket of silicone rubber. The slides and gasket are sealed and held together with two ordinary spring letter clips or clothes-pins. Cells may be inoculated by piercing the gasket with a hypodermic needle, or by removing the top slide and adding cells directly. Long-term cultivation with medium replacement is easy and efficient and addition of isotopes or other materials may be done aseptically.

Autoradiography↗
PubMed1978

Fluorescent labelling of cell membranes and cytoplasmic proteins in living cells.

Primary amino groups may be selectively labelled in living cell cytoplasmic components by staining with the covalently binding fluorochrome reagent fluorescamine. The reaction is extremely rapid and occurs at very low reagent concentrations. Cells survive such treatment and gradually remove or metabolize the labelled substances. Nuclei and nucleoli are not labelled, while lamellar cytoplasm, which contains little actual cytoplasm, is well demarcated, thus indicating that the method is useful for studies of cell membrane components. Labelled cell membranes can be prepared for further purification after preliminary external fixation of cell membranes with a supravital polyaldehyde fixative. The use of dimethylsulfoxide as a solvent for fluorescamine allows much longer survival of the cells than the use of acetone as a solvent. In addition, the use of high pH and borate buffer was not necessary to the labelling phenomenon.

Animals↗
PubMed1978

Computerized nuclear morphometry as an objective method for characterizing human cancer cell populations.

A new method for measuring differences in nuclear detail in chrome alum gallocyanin-stained nuclei of cells from human breast cancers was compared with conventional subjective grading and classification systems. The new method, termed computerized nuclear morphometry (CNM), gives a multivariate numerical score that correlates well with nuclear atypia and gives a higher reproducibility of classification than do subjective observations with conventional histological preparations. When 100 individual nuclei from each of 137 breast cancers were examined by CNM, there was a broad CNM score variation between patients but a good reproducibility for each tumor. When different parts of the same tumor were sampled, there was good reproducibility between samples, indicating that some breast cancers at least are "geometrically monoclonal." When these cancers were compared by the grading systems of WHO and Black, correlations of 0.43 and 0.48, respectively, were found. There was a poor correlation between CNM and classifications of tumor type, but in general there were high values for CNM in medullary tumors and low values in mucous tumors. Correlations between CNM and tumor progression and prognosis await future study of patients participating in the study.

Breast Neoplasms↗
PubMed1977

Topography of nonneoplastic and neoplastic cells of common origin.

The possibility that neoplastic transformation may characteristically alter cell surface morphology prompted a comparison by scanning electron microscopy of nonneoplastic and tumorigenic cell lines from a single clone of mouse embryo cells. Among those studied by scanning electron microscopy, six lines of this clone proved nonneoplastic, and nine others underwent neoplastic transformation in culture, as evidenced by tumor production in vivo. Combined cinephotomicrography and scanning electron microscopy allowed the determination of postmitotic time and topography of individual cells without perturbing the cells or detectably altering their surface morphology; no pattern of morphological change as a function of postmitotic time was evident in either nonneoplastic or neoplastic cell populations. Accordingly, these cell populations could be compared under their usual conditions of attached asynchronous growth despite differences in proliferation rates. Cells of the neoplastic lines were characteristically less spread, and some lines displayed greater morphological variability than was evident among cells of nonneoplastic lines. However, most cells in all nine neoplastic lines and all six nonneoplastic lines were smooth surfaced. Thus, the exaggerated incidence of microvilli, ruffles, or blebs reported for established tumor-derived lines and most morphologically transformed lines did not prove a reliable criterion of neoplastic state for these cell lines of common origin grown under the same culture conditions.

Animals↗
PubMed1977

Morphometric analysis of neoplastic transformation in rodent fibroblast cell lines.

Populations from seven pairs of neoplastic and nonneoplastic cell lines of common origin were compared for evidence of a change in morphotogical parameters accompanying neoplastic transformation. Projected cytoplasmic area, projected nuclear area, cell dry mass, nuclear dry mass, whole-cell absorption at 265 nm, and nuclear absorption at 265 nm were determined. Neoplastic transformation was consistently accompanied by three morphological features: (a) decrease in projected area of the lamellar cytoplasm; (b) decrease in the projected area of the nucleus; and (c) decrease in dry mass of the lamellar cytoplasm. Ultraviolet absorption was generally less in the neoplastic cells than in the nonneoplastic cells, while nuclear mass remained approximately the same. These results are interpreted as quantitative evidence that neoplastic transformation is accompanied by morphological change. The morphological events may be characterized as a loss in cell surface and nuclear membrane components.

Cell Division↗
PubMed1976

Cytometric analysis of neoplastic transformation of vertebrate cell populations.

Two parameters of neoplastic transformation in spontaneously transforming fibroblasts were examined. One parameter, the predilection for rounding of cells at metaphase, was studied using time-lapse cinephotomicrography and fixed, stained preparations. Ten different cell lines were assayed, including established lines of hamster, rat, and mouse cells, and six rodent cultures of known neoplastic potential as determined by animal injection and tumor production. There was a close correlation between the assumption by cells of a spherical shape at metaphase and their ability to form tumors on injection in syngeneic hosts. The projected area of adherent cells 24 hr after plating over a coverglass was used to assay the transition of these rodent cell populations in culture from nonneoplastic to neoplastic. As the cell population became neoplastic, there was a significant decrease in the mean projected area of the cells. Furthermore, as the cell cultures became capable of producing tumors, the projected area profile of the population shifted proportionally to smaller area classes.

Animals↗
PubMed1975

Metabolism of benzo(a)pyrene by human epithelial cells in vitro.

Primary cell cultures derived from human skin epithelium metabolized benzo(a)pyrene to three classes of compounds: phenols, quinones, and dihydrodiols. The relative proportions of metabolites varied according to the skin donor but differed from the pattern of metabolites in rat liver microsome preparations. While appreciable amounts of 7,8- and 9,10-dihydrodiol; 1,6-, 3,6-, and 6,12-quinone; and 3- and 9-hydroxy derivatives were found in the medium, no 4,5 (K-region)-dihydrodiol or epoxide was detected. Reduced amounts of quinones were produced when the cultures were pretreated with hydrocortisone before exposure to the hydrocarbon. The cultures did not require a period of enzyme induction for efficient metabolism of the hydrocarbon. Cultures of fibroblasts derived from the same skin samples as the epithelial cells metabolized the hydrocarbon but to a much different extent. Preexposure of the epithelial cell cultures to mixtures of polycyclic hydrocarbons resulted in a decrease in the amounts of carcinogen metabolized to phenols and dihydrodiols. These findings suggest that the prevalence of carcinomatous disease in humans is due to the differential capacity of the epithelial cells to metabolize potential carcinogens to active forms, a capacity reduced in fibroblasts or other nonepithelial cells. This suggestion is supported by the observations that supposedly normal prostate cells also efficiently metabolize polycyclic hydrocarbons in a manner similar to that of epidermal cells. No evidence of neoplastic transformation was seen in cytological preparations of cells exfoliated into the medium.

Animals↗