A radiofrequency electrode catheter-guide wire system for arterial occlusion.

Purpose: To describe the design of a radiofrequency (RF) electrode catheter/guide wire system to allow endovascular coagulation of vessels.

Materials And Methods: A circuit was created by modifying an ordinary microcatheter. An electrically conductive ring was placed at a microcatheter tip, and an extension lead at the hub site.

Long-Term Regulation of Renal Urea Transporters during Antidiuresis.

To produce a concentrated urine, the renal medulla needs hypertonicity for the reabsorption of free water from collecting duct. The single effect that increases interstitial tonicity in the outer medulla is the active NaCl reabsorption in the thick ascending limb, while the single effect in the inner medulla is the passive efflux of NaCl through the thin ascending limb. The passive mechanism in the inner medulla requires high interstitial urea concentration.

Aldosterone decreases UT-A1 urea transporter expression via the mineralocorticoid receptor.

Adrenalectomy in rats is associated with urinary concentrating and diluting defects. This study tested the effect of adrenal steroids on the UT-A1 urea transporter because it is involved in the urine-concentrating mechanism. Rats were adrenalectomized and given normal saline for 14 d, after which they received (1) vehicle, (2) aldosterone, or (3) spironolactone plus aldosterone.

Expression of urea transporters in the developing rat kidney.

Urea transport in the kidney is mediated by a family of transporter proteins that includes renal urea transporters (UT-A) and erythrocyte urea transporters (UT-B). Because newborn rats are not capable of producing concentrated urine, we examined the time of expression and the distribution of UT-A and UT-B in the developing rat kidney by light and electron microscopic immunocytochemistry. Kidneys from 16-, 18-, and 20-day-old fetuses, 1-, 4-, 7-, 14-, and 21-day-old pups, and adult animals were studied.