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T Yipintsoi

Publications and source records attributed to T Yipintsoi.

At least 55 records · Page 3Linked to original sources
PubMed1975

Increased cardiac contractility in acute uremia: interrelationships with hypertension.

To study the effects of acute uremia on the inotropic state of the rat heart, we subjected rats to bilateral nephrectomy and studied their hearts in the open chest 24 h later. Uremic rats had significantly higher systolic blood pressure than sham-operated animals. Left ventricular systolic pressure and maximum dP/dt, both during ejection and isovolumic contrations, were higher for any given end-diastolic pressure in hearts of uremic rats than in sham-operated animals. This difference in performance charcteristics was not abolished by doses of propranolol that blocked the heart rate response to isoproterenol. The administration of phenoxybenzamine during the 24 h of uremia abolished the blood pressure rise in uremic rats, but the increased contractile state persisted. Treatment of sham-operated animals with methoxamine to produce the same course of blood pressure as observed in uremic rats was also associated with an increased inotropic state. These results indicate that in the rat, acute uremia is associated with an increased inotropic state that is not mediated by beta-adrenergic mechanisms. The systolic hypertension of acute uremia is not the major cause of the increased contractility, although systolic hypertension without uremia can mimic the performance characteristics found in hearts of uremic rats.

Animals↗
PubMed1975

Capillary and cell wall permeability to potassium in isolated dog hearts.

From venous tracer-dilution curves recorded after 36 pulse injections of 42KCl and 131I-labeled albumin into the coronary artery inflow of 15 isolated canine heart preparations, we calculated maximal fractional extractions (Emax) and capillary permeability-surface area products (PScap) for 42K+ over a range of plasma flows (FP) from 0.3 to 1.7 ml min-1 g-u. At low FP (less than 1.0), Emax was 0.60 +/- 0.0l (mean +/- SD) and PScap was 0.72 +/- 0.20 ml min-1 g-1; at high FP (greater than 1.0), Emax decreased to 0.49 +/- 0.05 and PScap increased to 1.06 +/- 0.18. Continuous recording (gamma detector) of residual myocardial 42K+ in seven hearts showed that the mean fractional escape rate of tracer between 30 and 60 min after injection was 0.011-0.023 min-1; higher rates were observed at high FP, when the residue of 42K+ decreased to less than 10% of the injected dose by 60 min. Using PScap measured at high FP and considering the virtual intracellular volume of distribution for K+ to be 20 ml/g, we calculated the permeability-surface area product for sarcolemma (PScw) as 0.54-0.73 ml min-1 g-1, or about 50% of PScap. Considering sarcolemmal surface area (Scw) as 4,200 cm2/g and capillary surface area (Scap) as 500 cm2/g, cell permeability is low, with Pcw:Pcap being less than 0.08.

Animals↗
PubMed1975

Myocardial sodium extraction at varied coronary flows in the dog. Estimation of capillary permeability of residue and outflow detection.

Sudden injections of boluses containing both 131I-albumin and 24NaCl were made into the coronary artery inflow of isolated blood-perfused dog hearts. Indicator dilution curves were recorded using gamma emissions from both the intact heart and the coronary sinus outflow, with plasma flows, Fs, ranging from 0.3 to 1.8 ml/g min-1. Three measures of sodium extraction, E, during transcapillary passage were obtained from each site by comparison of the sodium and albumin curves. The most useful estimates of E were "instantaneous extractions" obtained from the later part of the upslope and the peak of the venous dilution curves (coronary sinus) or from the corresponding early phase of washout of the externally monitored curves (intact organ). Extractions were lower at higher flows. Permeability-surface area products, PS, were computed (1) by the formula PS equals -Fsloge(1 - E), (2) by fitting the observed dilution curves with a Krogh capillary-tissue cylinder model, and (3) by the approximating formula PS equals -Fsloge (1 - 1.14E). The two latter approaches provided a correction for back diffusion of tracer from tissue to blood. For sodium, the values of PS averaged 0.88 +/- 0.36 (SD) ml/g min-1, (n equals 52). At high flows, with Fs greater than 1.0 ml/g min-1, the values of PS averaged 1.01 +/- 0.38 ml/g min-1 (N equals 11). Assuming S equals 500 cm2/g and plasma to be 93% water, our findings suggest capillary permeabilities for sodium of about 3.1 times 10(-5) cm/sec.

Animals↗
PubMed1975

Alveolar lavage cytology in transplanted lungs. I. Staining methods and findings in dogs with autografts and allografts without immunosuppression.

Alveolar lavages were performed repetitively on the normal and transplanted lungs of dogs that had recieved autografts or allografts without immunosuppression. One half of the lavage returns was fixed as a cytologic smear; the other half was subjected to semi-thin section or electron microscopic examination. Of the staining methods was used, the periodic acid-Schiff (PAS) and Giemsa techniques were best for differentiating and counting cells. The Ladewig technique was best for evaluating the presence and location of fibrin. After autotransplantation, the proportion of so-called alveolar marcophages increased, reached a peak in 4 to 7 days, and then returned to normal. Phagocytized fibrin increased for the first postoperative week, but not extracellular fibrin was ever observed. After allotransplantation, a progressive decrease in the proportion, size, and vacuolization of so-called alveolar macrophages was noted along with an increase in extracellular fibrin. Intracellular fibrin could be detected only up to the third day. These findings define adequate methods for preparing and staining material obtained from diagnostic alveolar lavages, and they suggest that the procedure may serve as an index of lung allograft rejection.

Animals↗