适应性反应对中医药研究的启示

适应性反应是近年医学研究的热点问题之一,利用适应性反应已作为疾病防治的新战略,其核心和精髓是充分调动和激发机体内源性保护机制,增加机体适应性和抗损伤能力,维持机体自稳态.适应性反应的研究表明了机体自身存在着很强的内源性保护机制,其本质是适应性反应诱导了内源性保护物质(保护性蛋白等)的产生,而用药物等途径则可模拟或增强适应性保护作用.适应性反应与中医学的天人相应、正气学说、扶正固本、藏象学说、治未病思想、适应原中药、针灸经络等理论有诸多联系,对中医药研究有一定的启示,对于揭示中医学的科学内涵和实质、发展和弘扬中医理论及促进中西医结合均具有一定参考意义.     

NIFEDIPINE BLOCKS ACTH AND CORTISOL RELEASE IN MAN

1. The present study investigated the effect of prior administration of nifedipine on AVP-induced ACTH release in seven normal volunteers. Three protocols were used: 20 mg oral nifedipine; 0.14 pressor units intramuscular (i.m.) per kg bodyweight aqueous AVP; oral nifedipine plus i.m. AVP 90 min later. Plasma ACTH and cortisol were measured at intervals for 2.5 h during each test. 2. The mean peak plasma ACTH and cortisol levels and the mean peak changes from basal in these levels were significantly lower in the nifedipine/AVP test than in the AVP alone test. The integrated area under the cortisol time curve was significantly lower for the nifedipine/AVP test than that for the AVP test alone. Nifedipine alone caused no changes in ACTH or cortisol. 3. Acute administration of oral nifedipine caused an inhibition of AVP-stimulated ACTH and cortisol release in normal humans. This effect may be due to blockade of plasma membrane calcium channels normally activated during AVP stimulation of pituitary corticotrophs.     

Effect of intravenous ketanserin on the human action potential duration at fixed heart rate

Summary In this study any changes in action potential duration or Q-T interval due to acute doses of ketanserin were monitored. The effect of a bolus dose (10 or 20 mg) followed by an infusion (10 or 20 mg over 20 minutes) of ketanserin on the Q-T interval and action potential duration was studied in six patients undergoing routine cardiac catheterization. Action potential duration was measured with a silver-silver chloride electrode catheter while heart rate was kept constant by atrial pacing and reflex effects avoided by -adrenergic blockade. There were some prolongations of the action potential duration but they were not in excess of 40 msec and did not reach statistical significance (control 263±46.0 msec; bolus 269±52.1 msec; infusion 262±53.6 msec; nor were there any significant changes in Q-T interval. Thus acute intravenous doses of ketanserin, in the absence of hypokalaemia or other Q-T interval-prolonging drugs, have no consistent effect on Q-T interval or action potential duration; prolongation of the action potential, when it occurs, is small.     

精索静脉曲张不育症机理研究

精索静脉曲张是男子不育症的重要原因。但有关精索静脉曲张不育症机理至今仍不清楚。本文应用光镜和电镜对60例精索静脉曲张不育患者睾丸活检进行了一般生殖病理和超微结构病理研究,对部分病例作了生殖免疫病理和附睾功能检测。生精细胞脱落,间质病变和对侧睾丸病理变化是精索静脉曲张不育症睾丸的三种主要病理变化,其中间质血管病变和间质水肿是特征性损害。电镜观察到睾丸小血管病变。曲细精管界膜病变及基底小室病变,并认为在其不育机理上有重要意义。附睾功能检测表明附睾功能有一定损害,是精索静脉曲张不育机理中的重要环节。这一观点属首次提出。生殖免疫病理揭示有三分之一病例呈阳性反应。根据上述观察和精液检查,本文提出了精索静脉曲张不育症的较为完整的机理,对治疗有一定的指导意义。     

Cell-Growth Kinetics and Karyotype Analysis of Human Memory Lymphocytes Responding to Alloantigen and Mitogen

Peripheral-blood lymphocytes were primed in vitro with the mitogen phytohemagglutinin (PHA) or with allogeneic cells and their memory responses studied following sequential restimulation with either mitogen or alloantigen. Chromosome preparations were made every 12 hours following exposure to the stimulating agents. Cultures were labeled with BUdR for sister-chromatid staining of the chromosomes which provided information about the kinetics of cell growth and rates of sister chromatid exchange. Cultures containing no BUdR were used for the investigation of cell karyotypes after chromosome-banding.Following PHA as well as alloantigen restimulation, an earlier reaction of the responding cells was observed. The peak response after the first stimulation was found at 120 h with allogeneic stimulation and at 60 h with mitogen stimulation. In the second round of stimulation, the peak occurred after 48 h (allogeneic) and 36 h (PHA) and following the third stimulation after 36 h (allogeneic) and 24 h (PHA). The speed of cell growth was decreased following restimulation with either alloantigen and mitogen. In contrast to the allogeneic restimulation, the number of cells responding after PHA restimulation was decreased.No systematic numerical or structural aberration of the karyotype was detected following repeated stimulation with either alloantigen or mitogen. In this sense, the lymphocyte subpopulations selected by repeated stimulation did not differ from the starting material. On the other hand, the sister-chromatid exchange (SCE) frequency was increased following allogeneic restimulation, whereas it remained constant with PHA restimulation.     

Age-related profile of cardiovascular reactivity to norepinephrine and angiotensin II in normal and hypertensive man

Summary The interrelationships among age, cardiovascular pressor reactivity to intravenously infused norepinephrine (NE) or angiotensin II, and endogenous plasma NE or renin (PRA) levels were evaluated in 31 normal subjects and 37 patients with essential hypertension. In normal subjects both angiotensin II pressor dose and PRA decreased progressively with aging. Angiotensin pressor dose correlated positively with PRA (r=0.41,P<0.025) and inversely with age (r=–0.46,P<0.02). NE pressor dose and basal plasma NE were also positively correlated (r=0.53,P<0.005), but the two factors remained largely unchanged with aging. Findings in essential hypertension differed in certain aspects. Angiotensin II pressor dose did not correlate with either basal PRA or age; and pressor doses of NE and angiotensin II tended to be lower in some patients than in normal subjects. These findings indicate that aging is accompanied by a physiologic increase in cardiovascular reactivity to angiotensin II, probably due to a concomitant decrease in circulating renin. The dissociation between angiotensin pressor dose and PRA in essential hypertension suggests an interference from an other factor.This work was supported by the Swiss National Science Foundation     

Calcitonin gene-related peptide is present in mammalian cerebrovascular nerve fibres and dilates pial and peripheral arteries

Calcitonin gene-related peptide (CGRP) is a novel 37-amino acid peptide occurring in neurones within sensory ganglia, in brain stem, as well as in the walls of blood vessels of peripheral organs. Pial arteries of cat showed a well-developed supply of CGRP-positive nerve fibres. The peptide was found to be a potent dilator of both pial and peripheral vessels of rabbit and cat, and of pial vessels from man. The dilatory effect was independent of the vascular endothelium and was not mediated through adrenergic, cholinergic or histaminergic smooth muscle receptors. The neurogenic vasoconstriction induced by electrical field stimulation was temporarily inhibited by CGRP, as studied in central ear arteries from rabbits. The results suggest that CGRP is a transmitter or modulator playing a role in the regulation of vascular tone.     

Enhancement of attention in man with ACTH/MSH 4–10

Normal men were infused for 4 hr with ACTH/MSH 4–10 or a control solution. Behavioral testing after the infusion indicated that subjects who received ACTH/MSH 4–10 were less anxious and had better visual memory than control subjects but the predominant effect of the heptapeptide was to increase visual attention. It was specualted that ACTH/MSH 4–10 may be uniquely coded for attentional functioning.     

21世纪老年医学伦理学之探讨

21世纪人类全面进入人口老龄化,我国也进入了人口老年型国家的行列。文章叙述了21世纪我国老年人的特点,制定了衡量老年人生活质量的指标,并对提高老年人生活质量的对策,实现健康老龄化进行了医学伦理学方面的探讨。