心包肽类激素免疫组织化学及免疫电镜的研究

采用免疫组织化学、免疫电子显微镜及高效液相结合放射免疫学方法,研究人和 Wistar 大鼠心包,结果表明:心包组织中存在 ANF 和 AngⅡ样物质。在采用兔抗 ANF 为抗体时,心包组织的间皮细胞存在明显的金粒子标记颗粒,间皮细胞是主要的内分泌细胞。心包组织存在 Ang Ⅱ和3种分子形式ANF.本研究提示.心包除已知功能外,尚存在重要的内分泌功能.     

基于FT-CMR的心脏功能评估参数对心房颤动冷冻球囊消融患者治疗后复发的预测效能分析

目的 探讨分析基于心脏磁共振特征追踪技术(FT-CMR)的心脏功能评估参数对心房颤动冷冻球囊消融患者治疗后复发的预测效能。方法 选取2019年6月至2020年12月收治的126例预行冷冻球囊消融术的心房颤动患者为研究对象,术前均进行心脏磁共振检查,根据术后6个月内患者有无复发将其分为窦性心律组72例和房颤复发组54例。比较两组患者左心房应变及应变率参数,采用FT-CMR评估患者心脏功能,并进行单因素、多因素logistic回归分析,探讨FT-CMR心脏功能评估参数对心房颤动冷冻球囊消融术后复发的预测价值。结果 房颤复发组患者女性、高血压、糖尿病、非阵发性心房颤动比例显著高于窦性心律组(P<0.05)。房颤复发组患者左心房总应变(Es)、左心房正向应变率峰值(SRs)、左心房被动应变(Ee)、心室舒张早期负向应变率峰值(SRe)、左心房整体纵向应变(PLAS)参数值低于窦性心律组(P<0.05)。Logistic多因素回归分析结果显示,性别(OR=3.511,95%CI:1.036～11.906)、PLAS(OR=1.089,95%CI:1.039～1.141)是心房颤动冷冻...     

Renal and hormonal effects of alpha1-adrenoceptor blockade by bunazosin in essential hypertension

Summary The renal and hormonal effects of the ₁-adrenoceptor blocker bunazosin were examined in 6 patients with essential hypertension. Oral bunazosin for 4 to 12 weeks significantly decreased mean blood pressure by 10%, increased effective renal blood flow and creatinine clearance by 34% and 37%, respectively, the plasma norepinephrine concentration was elevated by 60%, and the plasma atrial natriuretic peptide level was lowered by 22%. The plasma renin activity and aldosterone concentration were unchanged. Thus, a moderate reduction in blood pressure was produced by bunazosin treatment while maintaining renal perfusion.     

Humoral and cellular effects of the K+-channel activator cromakalim in man

Summary The effect of cromakalim, a K⁺-channel activator, on the plasma renin-angiotensin-aldosterone system, catecholamines and -atrial natriuretic peptide, and on the intraerythrocyte concentration and transmembrane fluxes of Na⁺ and K⁺ has been investigated in 18 normal male subjects, in a double-blind parallel study. After a run-in period on placebo for 1 week, the subjects were treated either with placebo (n=6) or cromakalim (n=12) for 1 week.Plasma renin activity was significantly increased during cromakalim. No effect of cromakalim on plasma angiotensin II, aldosterone, adrenaline, noradrenaline and -atrial natriuretic peptide was demonstrated. The intra-erythrocyte K⁺ concentration was decreased during cromakalim administration and Ca²⁺-dependent K⁺-channels in red blood cells were increased.     

Effects of atrial natriuretic peptide on DNA synthesis and NADPH diaphorase activity in epitheliocytes and smooth muscle cells of the respiratory tract in newborn albino rats

Newborn rats received single intraperitoneal injections of atrial natriuretic peptide (1-28) in a dose of 3.2×10_-8 mol/kg on day 6 of life. Autoradiography with ³H-thymidine showed that the peptide inhibited DNA synthesis in smooth muscle cells of the respiratory tract. Pretreatment with nitric oxide synthase inhibitor NG-nitro-L-arginine methyl ester attenuated, but did not abolish the effect of atrial natriuretic peptide (1-28). Histochemical assay for NADPH diaphorase showed that nitric oxide constitutively produced in the epithelium is involved in the growth-inhibitory effect of atrial natriuretic peptide (1-28) on proliferating smooth muscle cells.     

Plasma levels of atrial natriuretic peptide are raised in essential hypertension during low and high sodium intake

Summary Plasma levels of -human atrial natriuretic peptide (hANP) were measured in 17 patients with primary hypertension (11 females, 6 males, aged 22–61; blood pressure systolic 154±7 mmHg, diastolic 92±4 mmHg) and in 9 normotensive controls (4 males, 5 females, aged 20–71; blood pressure systolic 117±4 mmHg, diastolic 76±2 mmHg) during unrestricted sodium diet, at the 4th day of a low sodium intake (40–60 mEq/day) and at the 6th day of sodium loading (280–320 mEq/day) both after an overnight rest and after 4 h of upright posture. In the controls, plasma levels of hANP at 8:00 a.m. were lowered from 73±11 to 49±7 pg/ml during low sodium diet and increased to 128±37 pg/ml after high salt intake. Plasma ANP levels were significantly lower after 4 h of upright posture during unrestricted, low and high sodium intake. In the hypertensive group, plasma ANP levels were elevated during unrestricted diet (203±43 pg/ml), during the low sodium period (139±31 pg/ml), and after high sodium intake (267±63 pg/ml) compared to the controls. All levels were lowered by upright posture. The absolute decrease was more pronounced compared to the normotensives, the relative decline was similar in both groups. In the hypertensives, plasma ANP levels significantly correlate with systolic and diastolic blood pressure (r=0.468,r=0.448,P<0.05) and with urinary aldosterone during unrestricted diet (r=0.536,P<0.05). There was an inverse correlation between plasma ANP levels and plasma renin concentration during low and high sodium intake (r=–0.469,r=–0.496,P<0.05).These studies demonstrate raised circulating plasma ANP levels in patients with essential hypertension. The modulation of ANP by different sodium intake and by upright posture is maintained similar to the changes in plasma ANP in normotensive controls. Raised ANP levels in the hypertensives are correlated with low renin secretion and high aldosterone excretion. High ANP levels, therefore, might indicate sodium retention in essential hypertension.Abbreviation ANP atrial natriuretic peptide Supported by a grant from Ministerium für Wissenschaft und Forschung, NRW     

Fine Structure of A: Autonomic Nerve Fibers and Terminals in Human Myocardium; and B: Myocardial Changes in Congenital Heart Disease

In a histological and fine structural study of right atrial biopsy specimens from 31 patients with rheumatic heart disease (RHD), aged 7 to 46 years, and 11 patients with congenital heart disease (CHD), aged 3 to 36 years, nerve fibers or endings were seen by electron microscopy in 11 specimens. There was concurrence of ordinary axons along with terminals bearing pale cholinergic or dark adrenergic synaptic vesicles. Smaller and denser cholinergic vesicles suggested proliferation followed by exhaustion of such nerve endings. The closest proximity of nerve terminal to muscle fiber was about 100 nm. In one RHD specimen a “specific terminal cell” was present between a nerve ending and muscle fiber; in another a possible neuromuscular contact was developing at the surface of a regenerating small muscle fiber with a few myofilaments. Unmyelinated axons amidst increased subendocardial and subepicardial collagen, with prominent fibroblasts and depleted muscle fibers, were seen more frequently in specimens of CHD. Loss of myofibrils and accumulation of mitochondria, with infrequent formation of lipofuscin bodies, characterized degenerating muscle fibers in CHD also, although to a lesser degree than in RHD (reported earlier, 1985). The myocardial blood vessels in CHD tended to have pale swollen endothelial cells and narrowed lumen. The most severely affected cases of CHD were those with (1) a very wide atrial septal defect (ASD), (2) ventricular septal defect (VSD) with vegetations near the defect, (3) 1 infundibular pulmonary stenosis, and (4) Fallot's tetralogy.     

Atrial fibrillation: a new explanation of the old phenomenon

We propose a new mechanism of atrial fibrillation basing on the results of 30 series of acute experiments on anesthetized cats. In brief, combination of two or more arrhythmogenic factors shortens the interval between the inward and outward ionic currents in cardiomyocytes to a critical value. Under these conditions repolarization of cardiomyocyte membrane reaches the excitation threshold before complete inactivation of the depolarizing currents. This inevitably results in autoexcitation of myocytes (or extrasystole), that in turn promotes repolarization. Once occurred, autoexcitation turns into self-triggering activity resembling tachyarrhythmia paroxysm.     

心钠素免疫反应在豚鼠耳蜗中的整体分布

目的 :研究豚鼠耳蜗中心钠素 (ANP)免疫反应的分布状态 ,为探讨ANP在耳蜗中的作用提供形态学基础。方法 :采用免疫组织化学ABC法检测ANP在正常豚鼠耳蜗各组织中的分布特征。结果 :在耳蜗 1～ 4回的血管纹、螺旋缘、Corti’s器、螺旋神经节和中间阶外壁的螺旋韧带均发现有ANP反应 (ANP IR)阳性产物 ;而耳蜗骨壁、前庭膜、鼓阶外壁的螺旋韧带和鼓阶的下壁ANP IR为阴性。结论 :耳蜗中的ANP在内耳淋巴液的生成和声信号的传导以及耳蜗血流量的调节等方面可能担负着重要的作用     

Atrial natriuretic factor (ANF) does not affect ion transport in human intestine but does in porcine intestine

The aim of this study was to test whether atrial natriuretic factor (ANF) exerts any effect on human intestinal ion transport, and the porcine intestine was used as a positive control of ANF's effects. Tissues from human proximal (n = 6) and distal (n = 6) colons, and from distal ileum (n = 6) were mounted in Ussing chambers, and short circuit current (I_sc) was measured subsequent to serosal application of ANF (10^--⁶ m), 8–Br-cyclic guanosine monophosphate (8–Br-cGMP) (10^--⁴ m), and theophylline (10^--² m). ANF did not affect I_sc whereas 8–Br-cGMP increased I_sc by 28 (8–53), 16 (3–36), and 16 (5–41) μA cm^-2 in the distal colon (DC), proximal colon (PC) and distal ileum (DI), respectively. Likewise, transepithelial potential difference (PD) became more negative by 5.0 (0.6–8.9), 2.5 (0.4–4.0) and 0.9 (0.3–2.3) mV in DC, PC, and DI, respectively, subsequent to addition of 8–Br-cGMP. I_sc and PD were further increased by theophylline. Additional radio-isotope flux studies in human colon revealed that ANF did not affect electroneutral sodium and chloride transport either. For comparison, ANF (10^--⁶ m) was administered to large intestinal tissues from young pigs in which ANF induced a significant increase in I_sc which was comparable to the 8–Br-cGMP response in humans. The porcine I_sc response was partly inhibited by chloride-free solution on the serosal side, by serosal application of bumetanide (10^--⁴ m) and BaCl₂ (10^--³ m), and mucosal application of the chloride-channel blocker diphenylamine-2–carboxylate (DPC) (10^--³ m). Mucosal amiloride (10^--⁵ m) pre-treatment reduced baseline I_sc but did not affect the porcine intestinal I_sc response to ANF. In vitro radio-autography demonstrated specific binding sites for ANF in porcine distal colon, whereas no apparent labelling was observed in human distal colon. These findings suggest that the lack of effect of ANF on sodium and chloride transport in human distal ileum and colon is probably due to lack of ANF receptors. In the porcine intestine, however, the I_S0 response induced by ANF seems to involve stimulation of electrogenic chloride secretion, whereas electrogenic sodium absorption seems unaffected.