Effect of bilateral nephrectomy on the recovery of blood pressure after acute hemorrhage in rats: Role of renin-angiotensin system

Summary The effect of bilateral nephrectomy, and administration of an inhibitor of angiotensin converting enzyme, on the recovery of arterial blood pressure after hemorrhage (loss of 1% of b.wt), was studied in male Sprague-Dawley rats. Neither manuver significantly affected the recovery of blood pressure within the first 10 min after hemorrhage. Thereafter, the recovery of the blood pressure was markedly suppressed. The study suggests that the initial recovery of blood pressure is unrelated to the kidneys, but the later one requires their presence and depends on the activity of the renin-angiotensin system.     

The effect of nicotine on blood pressure in the genetically hypertensive mouse

Summary Mice genetically selected for high and low blood pressure were exposed to nicotine via a single injected dose or addition to drinking water for 52 weeks. In the acute study, the response of mice with high blood pressure was a statistically significant increase in blood pressure. In the chronic study the pattern of response to nicotine ingestion was similar for mice with high blood pressure and those with low. Both lines responded with an increase in blood pressure after 6 weeks followed by a decrease to below baseline blood pressure at 12 weeks.This research was supported in part by an allocation from the General Research Fund of the University of Kansas.     

GlideScope视频喉镜用于经口与经鼻气管插管的临床观察

目的 观察GlideScope视频喉镜经口气管插管和经鼻气管插管的声门暴露情况、插管时间和血流动力学变化. 方法 在全身麻醉下行择期手术的患者200例,ASA Ⅰ～Ⅱ级,分为经口气管插管组和经鼻气管插管组.观察记录两组患者喉部显露分级、气管插管时间、气管插管前后的心率、血压,计算各时间点的收缩压-心率乘积（RPP）. 结果 使用GlideScope视频喉镜喉部显露分级为Ⅰ级和Ⅱ级的比例高达98%;经口插管组和经鼻插管组的插管时间分别为（43.3±9.8）s和（57.9±13.3）S,两组比较有显著差异;经口插管组的患者在气管插管时和气管插管后1～2 min内的心率、血压和RPP较麻醉诱导前显著升高,经鼻插管组的患者在气管插管后1 min时的心率和RPP较麻醉诱导前显著升高. 结论 使用GlideScope视频喉镜可改善喉部显露分级,经口气管插管所需的时间少于经鼻气管插管,而血流动力学变化强于经鼻气管插管.     

The effect of shock on blood oxidation-reduction potential

Oxidation-reduction (redox) potential measurements were made in the blood of rabbits subjected to hemorrhagic shock followed by treatment with a mild oxidizing agent (albumin). Control redox potential reading corrected for pH was –8.8±1.3 millivolts (mV) in arterial blood (A) and –18.0±2.0 mV in venous blood (V). This A-V difference indicated that hydrogen equivalents coming from muscle and other tissues were partially consumed in the lungs. A 20-mV drop on the V and a 13 mV on the A side was seen after shock. This did not fully return to control 2 h after return of the shed blood. Infusion of 2 g of albumin/kg/h raised the V redox potential to control, but it returned to untreated levels when the albumin was discontinued. The reductive load imposed on the animal by shock appeared to be large and not readily reversed by reperfusion or by the quantity of albumin given. Thus, it may be concluded that cellular respiration had not been adequately restored. This reductive load may impede recovery by suppression of cellular respiration and other cell and organ functions.     

Central tyramine prevents hypertension in uninephrectomized DOCA-saline treated rats

Summary Prevention of high blood pressure in uninephrectomized, DOCA-saline treated rats was observed after treatment with central tyramine precursors. We suggest that the high blood pressure is either due to relative lack of tyrosine, which might be caused by the hyperactivity of tyrosine hydroxylase, or to hypoactivity of the decarboxylase: in both cases the result is diminished tyramine synthesis.The authors wish to thank professor D. Ben-Ishay for productive discussions throughout the research and for his constant encouragement.     

Water movement between myocardial tissue and capillary blood during and after coronary reactive hyperemia as studied by continuous measurement of colloid osmotic pressure of cardiac venous blood

Summary Colloid osmotic pressure (COP) of blood from the great cardiac vein was continuously measured by the use of a membrane colloid osmometer during reactive hyperemia resulting from temporary occlusion of the anterior descending branch of left coronary artery. The COP increased sharply but transiently after the release, then it decreased below the initial level and gradually recovered. It was concluded that a measurable amount of water moved from the capillary blood into the myocardial tissue and then flowed back slowly into the capillary blood.     

Die Blutdruckwirkung des N-Isopropyl-nor-adrenalins

Summary N-Isopropyl-nor-adrenaline (aleudrine), which normally reduces the blood pressure, exerts after treatment with parasympathetic stimulants, especially after pilocarpine, an increase of the blood pressure, which is considerably stronger than that produced by adrenaline. This pressor effect of aleudrine is, contrary to the hypotensive action, cholinergic as it is abolished by atropine, whereas it remains fully unaffected by nicotinization. The pressor effect of aleudrine thus corresponds to the analogous action of choline, the mechanism of which was elucidated byForst.

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(Aleudrin)     

The effect of shock on blood oxidation-reduction potential.

Oxidation-reduction (redox) potential measurements were made in the blood of rabbits subjected to hemorrhagic shock followed by treatment with a mild oxidizing agent (albumin). Control redox potential reading corrected for pH was -8.8 +/- 1.3 millivolts (mV) in arterial blood (A) and -18.0 +/- 2.0 mV in venous blood (V). This A-V difference indicated that hydrogen equivalents coming from muscle and other tissues were partially consumed in the lungs. A 20-mV drop on the V and a 13 mV on the A side was seen after shock. This did not fully return to control 2 h after return of the shed blood. Infusion of 2 g of albumin/kg/h raised the V redox potential to control, but it returned to untreated levels when the albumin was discontinued. The reductive load imposed on the animal by shock appeared to be large and not readily reversed by reperfusion or by the quantity of albumin given. Thus, it may be concluded that cellular respiration had not been adequately restored. This reductive load may impede recovery by suppression of cellular respiration and other cell and organ functions.     

Blood flow rate in jejunal ischemia-reperfusion injury

We examined changes in the blood flow rate in the course of jejunal ischemic injury using a laser Doppler flowmeter. For this purpose, we designed a sensor holding system, which involved the fixation of the sensor to the jejunum and allowed their movements to be synthronized. When the jejunum was reperfused after 10 min of ischemia, the blood flow rate markedly increased and then gradually decreased to the initial level. A 30-min period of ischemia produced the slowest recovery of the blood flow rate. This system could be useful for monitoring the blood flow rate in different anatomical regions.     

Effect and fate of intravenously administered porphobilin in rats

Summary It rats after i.v. prophobilin, blood pressure and pulse rate remained stable, the animals were calm and moved freely with no symptoms or signs of nervous effect. Prophobilin was rapidly excreted in the urine.     

Phoenixin-14: detection and novel physiological implications in cardiac modulation and cardioprotection

Phoenixin-14 (PNX) is a newly identified peptide co-expressed in the hypothalamus with the anorexic and cardioactive Nesfatin-1. Like Nesfatin-1, PNX is able to cross the blood–brain barrier and this suggests a role in peripheral modulation. Preliminary mass spectrography data indicate that, in addition to the hypothalamus, PNX is present in the mammalian heart. This study aimed to quantify PNX expression in the rat heart, and to evaluate whether the peptide influences the myocardial function under basal condition and in the presence of ischemia/reperfusion (I/R). By ELISA the presence of PNX was detected in both hypothalamus and heart. In plasma of normal, but not of obese rats, the peptide concentrations increased after meal. Exposure of the isolated and Langendorff perfused rat heart to exogenous PNX induces a reduction of contractility and relaxation, without effects on coronary pressure and heart rate. As revealed by immunoblotting, these effects were accompanied by an increase of Erk1/2, Akt and eNOS phosphorylation. PNX (EC₅₀ dose), administered after ischemia, induced post-conditioning-like cardioprotection. This was revealed by a smaller infarct size and a better systolic recovery with respect to those detected on hearts exposed to I/R alone. The peptide also activates the cardioprotective RISK and SAFE cascades and inhibits apoptosis. These effects were also observed in the heart of obese rats. Our data provide a first evidence on the peripheral activity of PNX and on its direct cardiomodulatory and cardioprotective role under both normal conditions and in the presence of metabolic disorders.     

Biochemical effects of reperfusion after regional myocardial ischemia of different duration in the open chest dog]

Restoration of blood flow after 15 or 45 min. of ischemia induced an immediate recovery of phosphocreatine level and adenylate energy charge whereas ATP and total adenine nucleotides remained significantly below their normal values. These results prove that oxidative phosphorylations are not impaired but that a pool of myocardial adenine nucleotides is lost during ischemia which cannot be restored shortly after reperfusion. The significance of energy charge as a regulatory parameter in the myocardium is discussed.     

食物分类与血压的关系研究

目的通过对人群不同食物分类的摄入天数的调查,分析食物分类与血压之间的关系。方法随机从某单位选取101名职工为调查对象,年龄在31～57岁,男性34人,女性67人。所有调查对象均进行膳食问卷调查和血压的测量,通过logistics回归分析食物分类与血压之间的关系。结果血压偏高组人群平均每周摄入各类食物的比例均较血压正常少,其中蛋类及其制品、豆类及豆制品、谷类（大米,面食,杂粮）、牛奶及奶制品、肉类（猪,牛,羊,家禽）、新鲜蔬菜和水果的天数明显少于血压正常纽（P〈0．05）;通过logistics回归分析发现,谷类、牛奶及奶制品摄入的天数的增多对血压有一定的保护作用（P〈0．05）,其logistics回归分析OR值分别为0．61、0．41。结论食用谷类及奶制品对于预防高血压发生有重要的意义。     

Blood pressure lowering effect of eicosapentaenoic acid-rich diet in normotensive,hypertensive and hyperlipemic subjects

Summary A mackerel diet or a herring diet in which two cans of fish fillet were consumed daily over 2 weeks within a prescribed regimen, in a crossover design, were given to 15 normotensive volunteers, 14 patients with mild essential hypertension and eight patients with type IV and V hyperlipoproteinemia (HLP). In normotensives a markedly lower systolic and diastolic blood pressure at the end of the period on the mackerel diet could be observed, whereas in hypertensive and hyperlipemic subjects only systolic blood pressure was significantly decreased. After the herring diet, which served as control, changes in blood pressure were of a minor degree.     

Blood pressure lowering effect of eicosapentaenoic acid-rich diet in normotensive, hypertensive and hyperlipemic subjects

A mackerel diet or a herring diet in which two cans of fish fillet were consumed daily over 2 weeks within a prescribed regimen, in a crossover design, were given to 15 normotensive volunteers, 14 patients with mild essential hypertension and eight patients with type IV and V hyperlipoproteinemia (HLP). In normotensives a markedly lower systolic and diastolic blood pressure at the end of the period on the mackerel diet could be observed, whereas in hypertensive and hyperlipemic subjects only systolic blood pressure was significantly decreased. After the herring diet, which served as control, changes in blood pressure were of a minor degree.     

Effects of kallidinogenase on urinary kallikrein excretion and plasma prostanoid concentrations in patients with essential hypertension

The effects of kallidinogenase on urinary kallikrein excretion, plasma immunoreactive prostanoids and platelet aggregation were investigated in patients with essential hypertension. Urinary kallikrein excretion and plasma 6-keto PGF1 alpha concentration were significantly decreased in these patients. Significant decreases in blood pressure, as well as significant increases of urinary kallikrein excretion and plasma 6-keto PGF1 alpha concentration after kallidinogenase administration were also observed.     

Beneficial action of naloxone in splanchnic artery occlusion shock

Summary The effects of naloxone on mean arterial blood pressure, myocardial depressant factor (MDF) activity and survival, after splanchnic artery occlusion were studied in cats. Naloxone significantly improved survival in splanchnic artery occlusion shock and prevented the accumulation of MDF in the plasma.Supported in part by a research grant from the W. W. Smith Foundation.Acknowledgments. We gratefully acknowledge the expert technical assistance of Maureen Messenger.     

Effect of hypercapnia on the acid base states of the blood in the crab Carcinus maenas (L.) (Crustacea-Decapoda)]

When the crab Carcinus maenas respires in hypercapnic water, a respiratory acidosis occurs, which is progressively compensated by a rise of the blood bicarbonate concentration. The CO2 partial pressure in the blood increases in proportion to the change in ambient CO2 partial pressure. Therefore, the regulation of the acid-base status depends mainly on non-respiratory adjustments of the blood bicarbonate concentrations.     

Lack of pressor effect of dopamine in the pentobarbital-anesthetized rat

The blood pressure and heart rate responses to intravenous dopamine infusion at 2.5, 5.0 and 10.0 micrograms.min-1 X 100 g-1 were studied in conscious and pentobarbital-anesthetized Sprague-Dawley rats. In the conscious rats, dopamine caused a significant dose-related increase in the mean arterial blood pressure which was abolished in the anesthetized rats. The heart rate increased significantly only at the highest dose infused. The responses to equipressor doses of noradrenaline (40 ng.min-1 X 100 g-1) and phenylephrine (1.0 micrograms.min-1 X 100 g-1) were also suppressed in the anesthetized rats. The results suggest that pentobarbital anesthesia depresses the blood pressure response to dopamine infusion in the rat through a depression of activation of alpha-adrenoceptors.     

High potassium intake increases the plasma concentration and urinary excretion of vasopressin in the rat

The effect of alterations of dietary potassium intake on the plasma concentration and the urinary excretion of vasopressin was studied in male rats. Ingestion of a high potassium diet resulted in increases in the plasma concentrations of potassium and vasopressin, systolic blood pressure, urine flow, and urinary vasopressin excretion. Ingestion of a low potassium diet had little effect on the plasma vasopressin concentration and systolic blood pressure but caused decreases in the plasma potassium concentration and urinary vasopressin excretion. The results indicate that physiological changes in the plasma potassium concentration or some other consequence of altered dietary potassium intake can affect vasopressin release and excretion.