Renal regulation of salt balance: a primer for non-purists

The greater than 40-fold range of voluntary salt intake in humans requires corresponding adjustments in renal excretion to maintain balance. Although many mechanisms have been implicated in the regulation of salt output by the kidney, surprisingly little consideration has been given to their quantitative significance and possible interaction. This survey summarizes the effects of changes in glomerular filtration rate, proximal peritubular physical factors, and plasma concentrations of aldosterone and atrial natriuretic factor (ANF), singly and in combination, on the level of salt excretion. Contrary to expectation, even large increases in filtration or decreases in proximal reabsorption have only minor natriuretic effects, due to constancy of fractional reabsorption in downstream nephron segments. Lack of aldosterone release increases salt excretion as much or more than the upstream mechanisms, whereas ANF-induced inhibition of reabsorption in the medullary collccting duct has the largest effect. It may be concluded, therefore, that the potency of these natriuretic factors increases with distance along the nephron, even though each is operating on a progressively small tubular load. However, none of the mechanisms, in isolation, is sufficient to explain salt balance over the range of voluntary intake. Combination of factors demonstrates synergism rather than simple additivity, resulting in more than enough reserve capacity for salt excretion.     

EPF单克隆抗体杂交瘤细胞株的建立

本文用纯化的早孕因子免疫ＢＡＬＢ／Ｃ小鼠，通过鼠－鼠杂交瘤技术，成功地建立了２株分泌ＥＰＦ单克隆抗体的杂交瘤细胞。经检测，它们所分泌的抗体亚类均为ＩｇＧ１，毁交瘤染色体数目１００－１０６条，ＥＩＳＡ检测诱生腹水抗体效价为１：１．２８＊１０＾５，连续培养生物学性状稳定。抗ＥＰＦ抗原的单克隆抗体的建立，为深入研究ＥＰＦ的生物学性质、特征提供了有力的工具。     

Effects of Pyridoxalated Hemoglobin Polyoxyethylene Conjugate and Stroma-free Hemoglobin on Renal Vascular Responsiveness to Vasoactive Substances in Isolated Perfused Rat Kidney

Abstract: The effects of pyridoxalated hemoglobin polyoxyethylene conjugate (PHP) and stroma-free hemoglobin (SFH) on vascular responsiveness to various vasoactive substances were examined in isolated perfused rat kidneys. The kidneys isolated from rats were perfused with 6% PHP, 6% SFH, and 6% hydroxyethylstarch (HES) solution at a constant flow rate. Vascular responsiveness to acetylcholine (ACh), nitroglycerin (NG), norepinephrine (NE), and angiotensin-II (ANG-II) was examined by measuring the perfusion pressure (PP). Effects of inhibition of endothelium-derived relaxing factor (EDRF) by N^G-monomethyl L-arginine (L-NMMA) on NE-induced and ANG-II-induced renal vascular responses were examined. ACh and NG induced a dose-dependent decrease in perfusion pressure (PP) in all groups. NE and ANG-II induced an increase in PP in all groups, but NE-induced and ANG-II-induced responses in the PHP-perfused and SFH-perfused groups were significantly larger than those in the HES-perfused group. L-NMMA did not alter vascular responsiveness to NE and ANG-II. These results indicate that PHP and SFH do not inhibit EDRF induced by ACh, but hemoglobin moiety per se does augment the vascular responsiveness to NE and ANG-II in the isolated perfused rat kidney.     

Association of Vascular Endothelial Growth Factor Expression with Tumor Angiogenesis and with Early Relapse in Primary Breast Cancer

Angiogenesis is an independent prognostic indicator in breast cancer. In this report, the relationship between expression of vascular endothclial growth factor (VEGF; a selective mitogen for endothelial cells) and the microvessel density was examined in 103 primary breast cancers. The expression of VEGF was evaluated by immunocytochemical staining using anti-VEGF antibody. The microvessel density, which was determined by immunostaining for factor VIII antigen, in VEGF-rich tumors was clearly higher than that in VEGF-poor tumors ( P <0.01). There was a good correlation between VEGF expression and the increment of microvessel density. Furthermore, postoperative survey demonstrated that the relapse-free survival rate of VEGF-rich tumors was significantly worse than that of VEGF-poor tumors. It was suggested that the expression of VEGF is closely associated with the promotion of angiogenesis and with early relapse in primary breast cancer.     

Risk factors for Caesarean section in Italy: results of amulticentre study

A recent large increase in Caesarean section (CS) in Italy was the initial stimulus for a study to identify risk factors for CS and, if possible, to suggest strategies to counteract the rise. The study was conducted in three hospitals where a wide range of individual variables was collected from the clinical records and from personal interviews. Crude CS rates and odds ratios were evaluated for each single variable while logistic regression has been used to investigate possible confounding factors. The study involved 1316 consecutive deliveries. Crude CS rates were 29.4%, 15.7% and 16.1%. Variables identified as high risk factors were pre-eclampsia, previous CS, breech and other non-vertex presentations. Antenatal care under an obstetrician working in the same hospital, a low number of antenatal consultations, previous miscarriages, offer (by obstetrician) and request (by women) for CS showed significantly high odds ratios (ORs). Previous live births was strongly negatively associated with CS. No relationship between type of delivery and social status was observed while a physician factor was detected in all three hospitals where rates for different physicians ranged from 0% to 52.8%. Apart from the main medical indications for Caesarean section (previous CS, breech presentation), the results seem to indicate that individual practice style may be an important determinant of the wide variation in the rates of Caesarean delivery. While this may have been suspected before this study, these results are the first hard data to indicate that, in Italy, CS is widely performed for non-medical reasons.     

农村健康保险的精算体系

本文提出了我国农村健康保险的精算体系和测算保险费、管理费、储备金、预防保健费、保险因子、增加系数、医药费及其补偿比的实用方法。