Curtis H. Carlson

DISTRIBUTION AND EXCRETION OF RADIOFLUORIDE IN THE HUMAN

Summary One mg fluoride labeled with radiofluoride was ingested by each of 2 adult humans. Observations of renal clearance of fluoride, chloride and creatinine were made. Fluoride clearance always exceeded chloride clearance by many fold and increased with urine flow, but fluoride clearance was always less than creatinine clearance. Renal tubules in 2 individuals, reabsorbed respectively 51 and 63% of fluoride in the glomerular filtrate which indicates a net process of glomerular filtration with a variable amount of tubular reabsorption. Plasma contained 72% of whole blood radiofluoride and radiofluoride concentration of plasma exceeded that of parotid gland saliva. Measurement of uptake and release of the radioisotope by soft tissues and by the skeleton showed characteristic differences of radiofluoride retention in these tissues. Skeletal tissues retained the isotope but soft tissues lost nearly all their activity within 4 hours after ingestion.

Role of Histamine in Endotoxin Shock.

Summary Intravenous injection of lethal doses of endotoxin in anesthetized dogs results in rapid decrease in total blood histamine, a concomitant rise in plasma histamine, and increased peripheral vascular responsiveness to histamine. These findings support the view that histamine performs a crucial role in progressive development of hypotension following administration of endotoxin. Figure Appreciation is expressed to Lorentz E. Wittmers for technical assistance.

Preparation of carrier free radiofluoride with a new estimate of the half-life of F18☆

A method for producing carrier free radiofluoride in aqueous solution using proton bombardment of O/sup 18/ en riched water is described togetber with a new estimate of 109.7 minutes for the half life of F/sup 18/. (auth)

Radiofluoride Distribution in Tissues of Normal and Nephrectomized Rats.

Summary 1) Radiofluoride given by intraperitoneal injection was absorbed and distributed throughout fluid compartments of the rat. It was found in concentrations exceeding that of plasma in the skeleton and in the tail tendon. In all other soft tissues examined, concentration in tissue water was some fraction of plasma concentration. Tissue concentrations in nephrectomized animals were increased but the pattern of distribution was not changed. The skeleton sequestered the bulk of the radiofluoride which would have been excreted by the kidneys. 2) The radiofluoride content of tissues expressed in terms of chloride content of the tissues varied with the nature of the tissue. It was lowest in the brain, highest in skeletal muscle, and was increased in most tissues of nephrectomized animals. The soft tissue fluid compartment volumes are not the same for the 2 halogen anions fluoride and chloride.

Mechanisms of Autoregulation in Isolated Perfused Kidney.

Summary The present investigation has been concerned with mechanisms explaining autoregulation of renal blood flow. Data from experiments on the isolated perfused dog kidney suggest that as renal artery pressure is elevated, blood flow regulation is brought about by (a) combined effects of increased tissue pressure and Bowman capsule extravascular pressure, and (b) increases in post-glomerular viscosity resulting from glomerular filtration.