The effect of the thromboxane A2 synthesis inhibitor OKY-046 on renal function in rabbits following release of unilateral ureteral obstruction

A marked decrease in renal blood flow (RBF) and glomerular filtration rate (GFR) was found after 24, 48 and 72 hours of total unilateral ureteral obstruction (UUO) in the rabbit. Contralateral GFR showed a modest increase consistent with compensatory hypertrophy. The urinary excretion of thromboxane B2 (TxB2), the stable metabolite of the vasoconstrictor prostaglandin, thromboxane A2 (TxA2) was significantly elevated in the urine obtained following release of the obstructed ureter when compared to the TxB2 level in the urine from the contralateral kidney. Continuous infusion of OKY-046 at 100 micrograms./kg./min. over 24 hours during UUO decreased TxB2 excretion by greater than 80 per cent. However there was no significant preservation of RBF or GFR of the obstructed kidney following ureteral release despite the selective inhibition of TxA2. Moreover the increase in contralateral GFR was also abolished. Taken together with other studies these results strongly suggest that the potent vasoconstrictor TxA2 is not responsible for the rise in renal resistance that follows acute UUO.     

自身免疫甲状腺病循环和甲状腺内细胞毒性T细胞(T_8/S_6F_1)的实验研究

应用新型单克隆抗体T_8/S_6F_1和流体细胞测定仪双色荧光程序检测了15例Graves病和8例Hashimoto甲状腺炎患者循环和甲状腺内的细胞毒性T细胞(cytotoxic T ceils,Tc)的分布。传统的单克隆抗体CD_8(OKT_8或Leu_2)仅能检测含有两个次亚群——抑制性T细胞(Ts)和细胞毒性T细胞(Tc)的Ts/TcT细胞亚群,不能将它们区别开来。本文应用的单克隆抗体T_8/S-6F_1首次能够单独测定Tc亚群。Graves病和Hashimoto甲状腺炎患者的循环Tc亚群分别为27.6±11.2％和27.5％±12.2％,与正常对照组差异无显著性。两组患者甲状腺内的Tc亚群数目也未见增加。Graves病患者甲状腺内Te细胞为16.45±4.7％。本文结果提示:AITD患者循环内和甲状腺内的细胞毒性T细胞亚群的数目未见增加。     

Magnetic resonance imaging of prosthetic heart valves

To evaluate the safety of magnetic resonance (MR) imaging of prosthetic heart valves, nine different synthetic and tissue valves were studied ex vivo. Deflection was measured in 0.35-tesla (T) and 1.5-T superconducting magnets and at the edge of the bore of a 2.35-T electromagnet in field gradients of 5, 1.1, and 6.3 mT/cm, respectively. No valve deflected in the 0.35-T magnet; six synthetic valves deflected 0.25 degrees-3 degrees in the 1.5-T magnet; all valves deflected 1 degree-27 degrees at the edge of the 2.35-T magnet. Each valve was then submerged in a vial of water and the temperature was measured immediately before and after each of two spin-echo imaging sequences in the two superconducting magnets. No significant temperature rise followed exposure in either magnet. Image distortion varied from negligible to severe in both imagers; magnitude of distortion paralleled magnitude of deflection. These data suggest that patients with present-day prosthetic heart valves can be safely imaged in present-day MR imagers and that prosthesis-induced artifacts will not interfere with interpretation in most instances.     

Evidence for a bioactive clonidine-displacing substance in peripheral tissues and serum.

Clonidine-displacing substance (CDS) from brain is biologically active in the kidney and stomach and on platelets. To determine whether CDS is contained in these and other peripheral tissues, homogenates of fresh brain, eight other organs and serum from rat were ultrafiltered (less than 10,000 mol. wt only), dried and extracted with methanol. Evaluation by radioimmunoassay (RIA) using antibodies to p-aminoclonidine showed that adrenal gland and gastric fundus (GF) contained significantly greater amounts of CDS-like radioimmunoactivity than brain; intermediate-to-low activity was present in heart, small intestine, serum, kidney and liver; lung and skeletal muscle values were near-background. RIA-positive extracts elicited well-correlated contractile activity in a GF smooth muscle bioassay; contractions persisted in the presence of antagonists of various transmitters and modulators, but were abolished by low concentrations of the calcium channel blocker verapamil. Serum levels of CDS were profoundly reduced following removal of the adrenal glands. We conclude that a CDS-like substance is present not only in brain as previously reported, but also in peripheral organs and in the circulation.     

A computerized method for rapid quantification of gallbladder volume from real-time sonograms

A computerized method that requires only 1-2 minutes to quantify gallbladder volume from real-time sonograms is described. This time is considerably shorter than that required using the hand-calculation method. There was a highly significant correlation between gallbladder volumes calculated by computer and hand (r = 0.97; P less than .001).