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Biomedical subjects

M Cobb

Publications and source records attributed to M Cobb.

49 records · Page 3Linked to original sources
PubMed1986

The early involvement of pulmonary prostaglandins in hyperoxic lung injury.

To further study the role of arachidonic acid metabolites in the development of hyperoxic lung injury and the function of PMNs and/or alveolar macrophages in facilitating this role, we exposed adult rabbits to greater than 95% O2 or air for 24, 40, 48, or 65 hours. At the end of each study, bronchoalveolar lavage [BAL] of the left lung was performed, and the right lung was inflated and fixed for light and electron microscopy. PGE2, 6-keto-PGF1 alpha and thromboxane B2 were measured by RIA in arterial and venous plasma at the beginning and end of each study and in BAL fluid obtained at sacrifice. Production of these three PGs by BAL cells placed in cell culture was also measured. Significant hyperoxic lung injury did not develop until 65 hours, as evidenced by significant increase in BAL total protein and percent PMNs, and by morphologic findings. At 40 hours, however, BAL fluid PGE2 and 6-keto-PGF1 alpha increased and BAL cell production of all 3 PGs was significantly increased (p less than .05). In summary, the early PG increases observed in these studies may directly contribute to the development of hyperoxic lung injury or, rather, may be representative of a generalized increase in all arachidonic acid metabolites, including the lipoxygenase pathway. The increase in BAL cell PG production and increased PG concentrations in BAL fluid prior to any increase in BAL PMNs suggest that the AM may be the source of the early arachidonic acid metabolite increase in response to hyperoxia.

6-Ketoprostaglandin F1 alpha↗
PubMed1982

Fluorescence immunoassay in the clinical laboratory.

Currently applied to the measurement of proteins, hormones and drugs, fluorescence immunoassay (FIA) is a popular and fast-growing non-isotopic immunoassay technique. This paper describes a number of current FIA methodologies, including: homogeneous enzyme immunoassay with fluorescence detection; fluorogenic substrate detection: fluorescence polarization detection; fluorescent excitation transfer immunoassay; fluorescence protection immunoassay; and techniques that use solid-phase separation media.

Fluorescent Antibody Technique↗
PubMed1980

Lecithin supplementation in healthy volunteers: effect on cholesterol esterification and plasma, and bile lipids.

Plasma and bile lipids and in vitro cholesterol esterifying activity of plasma (mg CE/dl/6 h) were determined in healthy volunteers who supplemented their regular diets with 7.5 g doses of soya lecithin three times daily for a 4-week period. Lecithin ingestion by the 4 male and 6 female subjects did not produce any significant changes either in total plasma cholesterol (TC) level or cholesterol esterification. A small but significant reduction was observed in the plasma triglyceride (TG) and total phospholipid (TPL) levels after supplementation. The molar percent of bile acids (BA), TC and TPL as well as the lithogenic index (LI = TC/BA + TPL) in both hepatic and gallbladder bile were also unaltered by 4 weeks of lecithin supplementation. In vitro cholesterol esterification was found linearly related to plasma-free cholesterol (r = 0.60, p less than 0.01) cholesterol ester (r = 0.50, p less than 0.05), total phospholipid (r = 0.50, p less than 0.05), lecithin (r = 0.45, p less than 0.05), and triglyceride (r = 0.57, p less than 0.025) levels.

Adult↗
PubMed1980

The relationship between cytotoxicity and prognostically significant histologic changes in lymph nodes from patients with cancer of the breast.

Axillary lymph nodes obtained from 37 patients with cancer of the breast were used in a microcytotoxicity assay against a human mammary cancer cell line, ALAB. Cell suspensions made from 60 individual lymph nodes and 51 lymph node pools were tested. Each lymph node was graded for the extent of the histologic changes of sinus histiocytosis (SH), paracortical hyperplasia (PCH), and germinal center hyperplasia (GCH). High levels of cytotoxicity correlated significantly with the presence of SH and PCH. When multiple lymph nodes of individual patients were pooled and tested, a high intensity of GCH correlated with a low degree of cytototoxicity. The cytotoxic activity of pooled lymph nodes from different axillary regions was studied in 20 patients. In 7 of these patients, low axillary lymph node cells were more cytotoxic than high axillary node cells. The reverse was found for 7 patients, and there was no difference in cytotoxicity between axillary regions in 6. Cytotoxic lymph node pools had high SH and low GCH whether they were obtained from the low or high region. Noncytotoxic lymph node pools from the high axillary region had a low intensity of all three histologic reactions. In contrast, noncytotoxic lymph node pools from the low axillary regions had high intensities of SH, PCH, and GCH. These results suggest that germinal center hyperplasia in the lymph nodes nearest an advancing tumor is associated with a local suppression of cytotoxic cell activity.

Adult↗
PubMed1978

Experience with a simplification of the petroff method for laboratory diagnosis of mycobacteria in sputum.

In the original Petroff procedure sputum is digested with NaOH and the centrifuged deposit neutralized with HCl before culturing. A modification in which digestion is arrested by dilution with water and the sediment is seeded on buffered media is simpler, quicker, safer and in our hands seems to give a greater number of positive smears and cultures for mycobacteria with less overgrowth by contaminants. The usefulness of regular smear examinations for excluding tuberculosis in nonspecific chest complaints is questioned.

Bacteriological Techniques↗
PubMedDate not supplied

Immunological characteristics and clinical significance of anti-H in the Ah phenotype.

A red cell survival study with 51Chromium-labeled A1 cells was performed in a patient with the Ah phenotype whose serum contained IgM anti-H but not anti-A1. A1 cells were agglutinated weakly at 37 degrees C in the crossmatch, but not in the antiglobulin test. One hour after the survival study was begun, 67 percent of injected cells had been destroyed, and only 20 percent of the labeled cells remained after 24 hours. This study suggests that Ah individuals should be transfused only with Ah or Oh red cells.

ABO Blood-Group System↗
PubMedDate not supplied

Oral hairy leukoplakia with ultrastructural evidence of Merkel-like cells in human tongue epithelium.

The purpose of this investigation was to examine cells in the stratum basale and subjacent lamina propria of oral hairy leukoplakia (OHL) specimens for previously unreported morphological changes. Tongue biopsy specimens were obtained from ten HIV-positive and five healthy male patients and examined by light (LM) and transmission electron microscopy (TEM). Observations made during the investigation revealed the following: (1) LM comparisons of control and OHL specimens indicated that clear cells in the stratum basale ranged from 3 to 7 per 100 basal epithelial cells in healthy tongue mucosa vs. 6 to 15 in OHL. (2) Merkel-like cells were noted in the stratum basale of control biopsies from the dorsal-lateral tongue surface. However, the frequency of observation was so rare as to imply that their presence was an exception rather than the norm. (3) In contrast, Merkel-like cells in OHL specimens were commonly encountered, indicating a possible unique relationship to the pathology. (4) Merkel-like cells associated with OHL lesions were morphologically similar, in all respects, to that of control specimens except for the presence of large, membrane bound, dense granules that ranged in size from 150-300 nm. (5) All biopsies of OHL exhibited evidence of Epstein Barr virus in the stratum corneum and superficial layers of the stratum spinosum. (6) A mild inflammatory infiltrate associated with OHL specimens revealed cytopathic changes in fibroblasts that appeared related to the presence of lymphoid cell types; indicating a possible cytolytic lymphocyte-mediated degradation of antigen altered host cells.

Biopsy↗