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Biomedical subjects

C B Bargeron

Publications and source records attributed to C B Bargeron.

26 records · Page 2Linked to original sources
PubMed1983

Stromal damage in rabbit corneas exposed to CO2 laser radiation.

Threshold damage to the cornea from CO2 lasers is confined to the epithelium. Exposures well above the threshold for epithelial damage produce bowl-shaped stromal wounds. Light and electron microscopy and slit-lamp photographs all show a sharp demarcation between the damaged and undamaged regions 48 hr after exposure. The micrographs also show that the damaged region is accellular. Calculations of the expected temperature increases combined with analyses of slit lamp photographs show that the wound boundary corresponds to a surface of equal peak temperature increase. Comparisons with epithelial and endothelial damage conditions suggest that stromal, endothelial and epithelial cells have essentially the same thermal damage mechanism.

Animals↗
PubMed1981

Correlation between intimal thickness and fluid shear in human arteries.

A realistic pulsatile flow was passed through a cast of the aortic bifurcation of a 63-year-old male with mild atherosclerosis, and a laser Doppler anemometer was used to measure fluid velocities in the cast at 15 selected sites near the lateral and medial walls. Intimal, medial and adventitial thickness were measured, and sudanophilia was scored, at corresponding sites in the vessel from which the cast had been made. A negative correlation was found between intimal thickness (IT) and wall shear rate (i.e., the velocity gradient at the blood-artery interface). The strongest negative correlation (P less than 0.005) was between IT and "pulse shear rate" (PSR), defined by analogy with pulse pressure. Sudanophilia also correlated negatively with PSR (P less than 0.01). These results suggest that large excursions of interfacial shear, at levels too low to cause damage, may inhibit intimal thickening.

Arteries↗
PubMed1981

Correlation of human arterial morphology with hemodynamic measurements in arterial casts.

A realistic pulsatile flow was passed through a cast of the aortic bifurcation of a 63-yr-old male with mild atherosclerosis, and a laser Doppler anemometer was used to measure fluid velocities in the cast at 15 selected sites near the lateral and medial walls. Intimal, medial and adventitial thicknesses were measured and sudanophilia was scored at corresponding sites in the vessel from which the cast had been made. A negative correlation was found between intimal thickness (IT) and wall shear rate. The strongest negative correlation (p less than 0.005) was between IT and "pulse shear rate" (PSR), defined by analogy with pulse pressure. Sudanophilia also correlated negatively with PSR (p less than 0.01). Medial thickness correlated positively with shear rate, and most strongly with the mean (i.e., time-average) rate (p less than 0.005). From an analysis of the fluid mechanical data, it appears possible to separate the effects of bifurcation geometry and the shape of the arterial cross section on interfacial shear.

Aorta↗
PubMedDate not supplied

Distribution of the geometric parameters of human aortic bifurcations.

The distribution of flow divider offset, branch angle, and angular asymmetry in a collection of 70 human aortic bifurcations are reported. A computer algorithm was used to determine these parameters objectively. The mean values with standard deviations and ranges are: 1) magnitude of flow divider offset = 1.4 +/- 1.4 mm (range = 0.04 to 8.1 mm); 2) branch angle = 35.0 degrees +/- 11.1 degrees (range = 10.4 degrees to 61.3 degrees); and 3) angular asymmetry = 15.3 degrees +/- 12.9 degrees (range 0.2 degrees to 56.1 degrees). Since these parameters have been shown to have a significant influence on hemodynamic shear, their variability suggests a corresponding variability in the fluid dynamic stresses to which the bifurcations were exposed in life.

Adult↗
PubMedDate not supplied

Occurrence and identification of intracellular calcium crystals in pulmonary specimens.

Scanning electron microscopy, x-ray analysis studies and histochemical techniques have identified unusual birefringent intracellular calcium carbonate crystals seen in the sputum specimens of a 68-year-old man with cavitary pulmonary lesions. He was clinically diagnosed and treated for pulmonary tuberculosis. Although other etiologies are possible, we contend that the calcium salt crystals identified in the sputum in this patient represent a peripheral manifestation of tuberculosis which is rarely noticed in the sputum specimens.

Aged↗