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Biomedical subjects

R Rosenstein

Publications and source records attributed to R Rosenstein.

51 records · Page 3Linked to original sources
PubMed1977

Comparison of the reaction-rate and clot-density methods for determination of plasma fibrinogen.

The reaction-rate (Dade) and clot-density (Sherwood) methods for determining plasma fibrinogen were compared. Both require small sample volumes, are economical, and may be performed using commercially standardized instruments and reagents. Equivalent times were required for sample preparation. The results of the fibrinogen determinations were similar for plasmas of normal subjects, reference plasmas, those from patients with and without disseminated intravascular coagulation, and solutions of bovine fibrinogen. Both procedures could be made more economical by adjusting the amounts of certain reagents in the kits. High fibrin degradation product levels had no effect on the fibrinogen determination by either method. Advantages of the Sherwood method included digital readout (obviating further calculations) and the fact that the change in clot density could be plotted. The Dade method had the advantages of being less affected by high concentrations of heparin, being applicable to either citrated or oxalated plasma, requiring considerably less time (especially for certain abnormal plasmas), and requiring less technical sophistication.

Blood Coagulation↗
PubMed1975

Slow respiratory stimulant effect of hyperoxia in chemodenervated decerebrate cats.

A direct stimulating action of oxygen on the CO2 respiratory control system was determined from steady-state and dynamic observations in unanesthetized decerebrate cats. In peripheral nerve-intact animals, inhalation of oxygen (1 atm) produced a small but significant shift to the left as well as a decrease in slope in the steady-state VT vs. log PACO2 relationship. Carotid sinus neurotomy more than doubled the shift, to the extent that the mean PACO2 apneic point was lowered by 6.5 mmHg. Neither vagotomy nor chronic ablation of the area postrema had any detectable influence on the stimulating effect of oxygen on CO2 responsiveness. The arterial-alveolar PCO2 difference, prior to and following carotid chemo-denervation, remained unchanged or was increased by a negligible amount during oxygen inhalation. The oxygen threshold for respiratory stimulation, obtained isocapnically, occurred between 115 and 200 mmHg; VT then increased exponentially tending to level off as PAO2 approached 1 atm. The dynamic response to sudden presentation of oxygen after carotid chemodenervation consisted of a monotonic rise in VT, starting after 20-30 s with a t 1/2 of about 75 s.

Animals↗