High Flow Values Research Articles

Regional cerebral blood flow in dogs using a particle-distribution method.

SummaryIn this study a known activity of microspheres labeled with 169Yb was injected into the left heart of lightly anesthetized dogs. Prior to injection of microspheres, cardiac output was determined by the isotope dilution technique using 42K or 86Rb. Blood flow to the cerebral cortex, white matter, thalamus, cerebellum, and caudate nucleus was determined in ml/min·g from fractional distribution of particles in tissue samples. Total brain blood flow in ml/min·g was estimated from the radioactivity observed in the remaining brain tissue. Comparison of dogs breathing air with dogs breathing 5% CO2 showed that flow values were significantly increased (p<.05) with 5% CO2 for all areas except white matter. Old dogs tended to show higher flow values than young dogs. Flow values obtained in this study were compared with values reported by others using different methods. The distribution of the particles in the brain was checked by autoradiography.

Blood flow in kidney transplants. A clinical evaluation of the 133 xenon method.

(1) The xenon method has been used to measure renal blood flow in 60 of the first 67 kidney transplants carried out in this department. (2) The method has proved to be of definite clinical value as a check of the perfusion of the kidney at the time of transplantation. (3) Persistently low flow values or values that decline markedly during the course of the operation are bad prognostic signs. With a flow value below approximately 100 ml/min/100 g there has been no eventual function. (4) A high flow value has been associated with either immediate or later renal function.

Terrestrial heat flow in Hungarian Permian strata

Latest measurements of terrestrial heat flow in the Hungarian and Russian parts of the Carpathian basin confirm previously measured high flow values between 2.0–3.3 μcal/cm2 sec. Recent measurement in the Permian anticline structure of the Mecseck. Mts. in Hungary gave 2.4 μcal/cm2sec, whereas in the Russian part of the basin, near to the Hungarian border 2.6 μcal/cm2 sec was measured in Miocene sediments. For more than 100000 km2 surface of the Carpathian basin covered by Hungary and parts of Slovakia and Russian the high heat flow is an established fact.

CLEARANCE- UND STOP-FLOW-UNTERSUCHUNGEN AN INTAKTEN UND DIABETES-INSIPIDUS-RATTEN IN WASSER- UND OSMOTISCHER DIURESE OHNE UND MIT ZUFUHR EXOGENEN VASOPRESSINS

ABSTRACT To clarify the significance of vasopressin on various parameters of renal function, clearance and »stop-flow« tests on intact rats and those with induced diabetes insipidus were carried out during water and osmotic (mannitol) diuresis. With regard to renal clearance, urinary concentration and renal output, water diuresis in the intact and diabetic insipidus rats was the same: low urine osmolarity, low electrolyte concentration, positive free water clearance and low rate of electrolyte excretion. The concentration patterns taken 3 minutes after ureteral occlusion showed for Na+ and Cl−: low free flow values and proximal maximum; osmolarity: low free flow values with a distal maximum below the plasma concentration; creatinine: distal maximum; urea: high free flow values with distal maximum. In the osmotic diuresis of intact animals, the electrolyte concentration was substantially higher; correspondingly, excretory output was much increased as compared to water diuresis, with negative free water clearance. The »stop-flow« patterns for Na+ and Cl− – starting with 70–100 mmol/l – showed a distal minimum, for osmolarity a distal maximum; and the same for creatinine and urea. The measured parameters obtained from diabetic insipidus animals in osmotic diuresis showed a marked approximation – up to equivalence – to that of intact and diabetic insipidus animals in water diuresis. When diabetes insipidus animals in osmotic diuresis were administered arginine-vasopressin as a continuous infusion, the results completely matched those of the measured parameters in the osmotic diuresis of intact animals. The importance of vasopressin on renal transports can thus be demonstrated not only by clearance and excretory tests, but also by the concentration patterns after ureteral occlusion.