PubMed Health⌕ Search

Biomedical subjects

S M Cassan

Publications and source records attributed to S M Cassan.

15 recordsLinked to original sources
PubMed1976

Ultrastructural morphometry of the blood-air barrier in pulmonary sarcoidosis.

Stereologic techniques were utilized in an electron microscopic study of biopsy samples obtained from the lungs of seven patients with pulmonary sarcoidosis. Relative fractional volumes of alveolar septal components and the arithmetic mean thickness and harmonic mean thickness of alveolocapillary membranes (blood-air barrier) were compared with values for normal lungs. Based on morphometric analysis, increases in the arithmetic mean thickness and the harmonic mean thickness of the alveolocapillary membranes appeared too small to account for the reduction in gas transfer present; however, there was a quantitative relative increase in interstitial tissue in alveolar septa, which does not take part in gas exchange, at the expense of the capillary bed, which is critical to this function.

Capillaries↗
PubMed1976

Fine structural morphometry of diffuse lung diseases with abnormal blood-air gas transfer.

Samples of lung biopsy tissue from nine patients with normal lungs, seven with pulmonary sarcoidosis, nine with diffuse interstitial pulmonary fibrosis, seven with histiocytosis X, and one with asbestosis were analyzed by morphometric techniques applied to electron micrographs, and the results were subjected to rank-sum analysis. Within the limits of the sampling method and the mathematical predictions of others, the general rejection of the constructed hypothesis in this study supports the conclusion that factors other than increase in the arithmetic of harmonic mean thickness of the blood-air barrier are critical to impaired gas transfer in the diseases studied.

Adult↗
PubMed1975

Nitrogen dioxide and the erythrocyte redox state.

Normal human erythrocytes were exposed for two hours at 38 C to an atmosphere of air containing variable concentrations of nitrogen dioxide, in order to detect any primary cytoplasmic effect of NO2 on the calculated oxidation-reduction (redox) ratio ([NAD+]/[NADH]) of a mitochondria-free cell. Substantial increases in the redox ratio were noted only when NO2 concentrations exceeded 15 ppm. In the range of 15 to 500 ppm NO2, the increase in the redox ratio significantly correlated with the NO2 concentration (r=.71; p less than .01). Intracellular to extracellular anion distribution ratios for chloride, lactate, and pyruvate were similar in NO2 and non-NO2 exposed cells, suggesting absence of a substantial hemolytic effect. These data identify a direct cytoplasmic NO2-induced biochemical change that may be mediated by a mechanism other than lipid peroxidation. Alteration of hemoglobin or NAD-NADH-dependent enzyme activity is suggested.

Cell Fractionation↗
PubMed1975

Application of ultrastructural morphometry to lung biopsy specimens in pulmonary histiocytosis X.

Stereological techniques were applied to an electron microscopic study of biopsy samples from nine human lungs with diffuse pulmonary histiocytosis X, and the results were compared with values for normal lungs. This made possible a morphometric analysis of the tissue changes associated with the measurable abnormalities in gas transfer present in this disease. The small increases in arithmetic mean thickness of the alveolar-capillary membranes appeared insufficient to account for the reduction in gas transfer present. When compared with normal lung, a threefold increase in volumetric fraction of septal intercapillary tissue was found along with a corresponding decrease in septal capillaries. While uniformity of distribution cannot be determined by this method, it appears that abnormalities of blood gas transfer in this disease result primarily from a decrease in the available diffusing surface and the ventilation-perfusion distrubances with which these tissue changes are associated.

Adult↗
PubMed1975

Ultrastructural morphometry of the diffusion surface in a case of pulmonary asbestosis.

A combination of electron microscopy and stereologic principles has allowed an evaluation of the contribution of structures in the blood-air barrier to gas exchange across it. In the present study this method was applied to biopsy material from the lungs of a patient with asbestosis. Within the limits of the sampling method, the results of the study are interpreted to indicate that measurable diffusion abnormalities were principally due to changes other than an increase in membrane thickness.

Adult↗
PubMed1975

The effect of vitamin E on NO2 induced redox changes in the human erythrocyte.

Human erythrocytes admixed with vitamin E supplements (50 mug/ml) were exposed to NO2 in concentrations of 200-600 p.p.m. at 37 degrees C for 2 h. No protective effect against the increase in the redox ratio [NAD+]/[NADH]normally produced by NO2 was observed. It is postulated that NO2 increases the redox ratio by a mechanism independent of that producing hemolysis and prevented by vitamin E. This may involve alteration of NADH dependent enzymes by NO2.

Erythrocytes↗