共查询到20条相似文献，搜索用时 15 毫秒
1.
Plasma dopamine beta-hydroxylase: a possible aid in the study and evaluation of hypertension 总被引：2，自引：0，他引：2
S M Schanberg R A Stone N Kirshner J C Gunnells R R Robinson 《Science (New York, N.Y.)》1974,183(124):523-525
The activity of dopamine beta-hydroxylase (DBH) in plasma ranged from 2 to 100 units per liter of plasma in 82 apparently healthy subjects (ages 22 to 35 years). A nonnormal pattern of distribution was evident: 62 subjects had values below 35 units (18 +/- 1), while 13 of the remaining 20 subjects had values above 60 units (80 +/- 5). Those with low DBH activity had lower values for urinary catecholamine excretion (31 +/- 3 micrograms), with normal and stable blood pressure; those with high DBH activity had higher values for urinary catecholamine excretion (72 +/- 6 micrograms), with greater lability of arterial blood pressure. The DBH activity was significantly elevated in patients with labile (74 +/- 2 mm-Hg) or fixed (57 +/- 2 mm-Hg) essential hypertension. The results indicate that plasma DBH activity is low and that it falls within a narrow range in young adults with normal and stable blood pressure. 相似文献
2.
Systolic blood pressure measurements were made on normal human subjects throughout entire nights of natural sleep and were correlated with cyclical changes in electroencephalographic patterns. During the recurrent rapid-eye-movement phase of sleep mean blood pressure levels were found to be generally higher, and the minute-to-minute variability of level was much greater than during the remainder of sleep. 相似文献
3.
青钱柳对家兔血液循环的影响 总被引：2，自引：0，他引：2
为探讨青钱柳[Cyclocarya Paliurus（Batal.）Iljinsk]对家兔动脉血压、心率及其肠系膜微循环的影响,经耳缘静脉注射0.1%青钱柳溶液后,分别观察给药后（1、5、10、20、30、60 min）家兔微动、静脉管径及血流速度、血流量变化、动脉血压、心率的变化情况。结果表明：耳缘静脉注射0.1%青钱柳溶液后,家兔动脉血压、心率显著降低（P〈0.05或P〈0.01）,而肠系膜微动、静脉血管扩张,血液流速加快,血流量增加（P〈0.05或P〈0.01）。可见,青钱柳具有扩张肠系膜微动、静脉血管及加快血液流速、增加血流量、降低动脉血压和心率的作用。 相似文献
4.
硒与奶牛红细胞膜功能的关系研究 总被引：2，自引：1，他引：1
对奶牛血硒含量、抗氧化酶活力、红细胞膜物理特性、不同硒营养奶牛谷胱甘肽过氧化物酶活力的变化进行测定。结果表明,奶牛血硒含量具有地区差异性;试验A组奶牛全血中几种重要的抗氧化酶—谷胱甘肽过氧化物酶、超氧化物歧化酶、过氧化氢酶活力明显下降;细胞膜蛋白质含量明显低于对照组,其他物理特性也有所改变,表现为在低硒条件下红细胞膜流动性降低、微黏度增加、渗透脆性增加、离子泵活力下降。经冰冻蚀刻电镜蛋白质形态学观察,试验A组奶牛红细胞膜蛋白质微粒分布稀少、个别区域有丛簇状分布;在试验B组中对各组奶牛添以不同硒营养的饲料,在此浓度梯度中显示有硒最适添加量,用此添加量的含硒饲料中谷胱甘肽过氧化物酶活力最高,添加量少于或多于此值时有机体的抗氧化性都将受到影响。 相似文献
5.
L Raymond R B Weiskopf M J Halsey A Goldfien E I Eger J W Severinghaus 《Science (New York, N.Y.)》1972,176(40):1250-1252
Breathing a mixture of 75 percent helium and 25 percent oxygen instead of 75 percent nitrogen and 25 percent oxygen reduced the occurrence of dangerous cardiac arrhythmias after ligation of the circumflex coronary artery in open-chest dogs anesthetized with pentobarbital. In dogs not subjected to circumflex ligation, the sensitivity of blood pressure, heart rate, and extrasystoles to epinephrine injected intravenously was not altered by the substitution of helium for nitrogen; however, helium did reduce the baseline heart rate and the concentration of endogenous plasma catecholamines. The antiarrhythmic effect of helium may thus be mediated by changes in sympathetic activity. 相似文献
6.
The methoxy analogs of epinephrine, norepinephrine, and dopamine manifest some activity on smooth muscle and blood pressure. Metanephrine is as potent as epinephrine on rabbit aortic strips. The same compounds demonstrate a lesser potency on rabbit duodenum preparation, while 3-methoxy-dopamine produces a slight contraction of the duodenum. Both metanephrine and 3-methoxy-dopamine have 15 to 25 percent of the pressor activity of the original nonmethylated catecholamines. Normetanephrine is 1/600 as active as norepinephrine on the blood pressure of the cat. 相似文献
7.
Constriction of the renal artery and controlled reduction of renal perfusion pressure is followed by a prompt increase in systemic renin activity and a concomitant rise in blood pressure in trained, unanesthetized dogs. The elevated blood pressure induced by the renal artery stenosis can be prevented by prior treatment with the nonapeptide Pyr-Trp-Pro-Arg-Pro-Gln-Ile-Pro-Pro, which blocks conversion of angiotensin I to angiotensin II. Further, the nonapeptide can restore systemic pressure to normnal in the early phase of renovascular hypertension. These results offer strong evidence that the renin-angiotensin system is responsible for the initiation of hypertension in the unilaterally nephrectomized dog with renal artery constriction. 相似文献
8.
Intelligence and blood pressure in the aged 总被引：4，自引：0，他引：4
Diastolic hypertension was related to significant intellectual loss over a 10-year period among individuals initially examined in their 60's. Such loss was not found in their age peers in association with normal or mild elevations of blood pressure. Of the subjects initially examined at 70 to 79 years of age, none with hypertension completed the follow-up program, and those with normal and mildly elevated blood pressure showed some intellectual decline over the decade. At the initial examination, hypertension was related to lower intelligence test scores only among those subjects who subsequently did not complete the follow-up program. The results suggest that hypertension is related to intellectual changes among the aged. 相似文献
9.
G. P. Drobot V. A. Zabiyakin A. E. Stepanova S. Yu. Smolentsev 《Russian Agricultural Sciences》2017,43(2):177-179
The cytochemical organization of neutrophils and pseudoeosinophils in different classes of vertebrates is poorly studied. The purpose of this study is to determine the cytochemical status of pseudoeosinophils in the blood of guineafowl. We analyzed the blood of Volga white guineafowl breed, colored blue and gray-speckled guineafowl populations (174, 186, and 208 days) and one-day-old nestlings of these populations. It was found that the changes in cytochemical blood cell parameters during the period of development (days 174–208) were multidirectional: the activity of acid phosphatase and glycogen increased, while the activity of myeloperoxidase and alkaline phosphatase decreased. The activity rates of myeloperoxidase and lysosomal-cationic proteins during this period were stable. 相似文献
10.
该研究对实验性缺硒病雏鸭检测了七项生化指标。结果表明,全血谷胱甘肽过氧化物酶(GSH—px)活性与血硒含量呈正相关(r=O.98,(?)多=1.53+103.85x);发病鸭组与对照鸭组相比较,全血GSH-px、血浆脂肪酶和血浆蛋白酶活性降低,但粪脂含量升高,且组间差异显著(P<0.01)。血浆淀粉酶和血糖未见显著变化。 相似文献
11.
PIEPER HP 《Science (New York, N.Y.)》1960,131(3403):828-829
A pump with sinusoidal piston movement was connected to the abdominal aorta of intact anesthetized dogs, causing slow oscillations of arterial blood pressure. Evidence was found for the existence of a mechanism which enables the heart to adjust its output immediately to changes of peripheral outflow. 相似文献
12.
对实验性缺硒病雏鸡,检测了六项生化指标。结果表明,全血谷胱甘肽过氧化物酶活性与血硒含量呈正相关(r=0.7679);发病鸡组与对照鸡组相比,全血谷胱甘肽过氧化物酶活性明显降低,血浆淀粉酶活性和粪脂含量却升高,而且组间差异显著(P<0.01);血浆中蛋白酶、脂肪酶及血糖含量未见有规律性变化。 相似文献
13.
Aftershocks caused by pore fluid flow? 总被引：2，自引：0，他引：2
Large shallow earthquakes can induce changes in the fluid pore pressure that are comparable to stress drops on faults. The subsequent redistribution of pore pressure as a result of fluid flow slowly decreases the strength of rock and may result in delayed fracture. The agreement between computed rates of decay and observed rates of aftershock activity suggests that this is an attractive mechanism for aftershockss. 相似文献
14.
６头山羊在吸入安氟醚５，１５，３０，４５，６０，７５和９０ｍｉｎ时，同步测定终末呼气和血液中安氟醚浓度，血气及血压等。结果显示：在开档期间，随吸入时间的延长，终末呼气和血液安氟醚浓度均上升，但停止供药，两浓度则下降；随吸入安氟醚浓度的增加，血气和血压发生明显的变化，ｐＨａ减少，ＰａＣＯ２升高，血压下降，平均动脉压与终末呼气安氟醚浓度高度相关（ｒ＝－０．９７２１）。随安氟醚浓度的减少，血气和血压也 相似文献
15.
中药材飞龙掌血研究进展 总被引：1，自引：1，他引：0
综述了飞龙掌血中香豆素、生物碱、挥发油、甾醇、树脂和三萜类化合物共六大类化学成分的研究成果,并介绍了近20年来发现的飞龙掌血抗肿瘤、升压、抗凝血、抗炎镇痛、扩血管、抑制流感病毒复制、解痉挛和利尿等药理活性,为我国丰富飞龙掌血资源的开发利用提供了新的思路。 相似文献
16.
以鲜切莲藕为载体,研究超高压处理对鲜切莲藕的Vc、可溶性固形物、菌落总数、质构、多酚氧化酶(polyphenol oxidase,PPO)活性等各项品质指标及其在贮藏过程中的影响。结果表明:随着处理压力的增大和保压时间的延长,莲藕中可溶性固形物、总酚含量基本保持不变(P0.05);还原型Vc、PPO的活性、脆度均呈下降趋势(P0.05)。压力对微生物的影响效果比较显著(P0.05);随着压力的增加,灭菌效果越好,但延长保压时间,杀菌效果并没有进一步提升。在贮藏期间,与未经超高压处理的对照组相比,超高压处理后的鲜切莲藕Vc损失程度较小,可溶性固形物损失逐渐增大,总酚含量逐渐降低,而PPO活性变化趋势则是先降低后升高,再逐渐降低;并且随着贮藏时间的延长,莲藕的脆度值呈下降趋势,L*值下降,a*值上升,总体色差增大。整个贮藏期间500 MPa处理的莲藕色差变化最小。总菌落数随贮藏时间的增加而不断增加,但总体来说压力越大,微生物增长速度越慢。对超高压处理后莲藕细胞结构进行显微观察,发现高压处理可以破坏细胞结构,并且压力越大对细胞结构的破坏作用越明显。 相似文献
17.
高温、低盐对菲律宾蛤仔免疫能力的影响 总被引：2，自引：0，他引：2
为查明温度(21、30℃)和盐度(7、15、32)互作对菲律宾蛤仔Ruditapes philippinarum免疫能力的影响,对不同温度和盐度条件下试验0、3、6、12、24、48、72 h时,体质量为(14.8±0.731)g蛤仔的血细胞数、血淋巴吞噬能力和渗透压,以及血清中溶菌酶(LZM)、碱性磷酸酶(AKP)活性的变化进行了研究。结果表明:以各指标0 h水平为对照,常温常盐组(21℃,32)蛤仔各指标在0~72 h内虽有波动,但变化并不显著(P0.05);各试验组蛤仔血细胞数有不同的变化趋势,72 h时,常温低盐组(21℃,7)蛤仔恢复初始水平,而常温中盐组(21℃,15)、高温中盐组(30℃,15)和高温常盐组(30℃,32)蛤仔血细胞数最终仍未恢复,高温低盐组(30℃,7)蛤仔虽在24 h时恢复初始水平,但在48 h时全部死亡;高温常盐组蛤仔吞噬能力先升高后降低在72 h时仍低于初始水平(P0.05),2个中盐组和常温低盐组蛤仔吞噬活性最终恢复,而高温低盐组蛤仔吞噬活性在24 h时仍处于较高水平(P0.05);各试验组蛤仔LZM活性在72 h时均显著高于初始水平(P0.05);常温中盐组蛤仔AKP活性在3 h出现最大值,最终所有试验组AKP在72 h时恢复初始水平;2个中盐组和2个低盐组蛤仔渗透压均逐渐降低,而高温常盐组蛤仔渗透压逐渐升高,在72 h时均未恢复初始水平。研究表明,温度升高的同时降低盐度,将会对贝类免疫能力造成严重的影响,这可能是夏季滩涂贝类死亡率较高的一个重要原因。 相似文献
18.
Does the release of potassium from astrocyte endfeet regulate cerebral blood flow? 总被引：14，自引：0，他引：14
Local increases in neuronal activity within the brain lead to dilation of blood vessels and to increased regional cerebral blood flow. Increases in extracellular potassium concentration are known to dilate cerebral arterioles. Recent studies have suggested that the potassium released by active neurons is transported through astrocytic glial cells and released from their endfeet onto blood vessels. The results of computer simulations of potassium dynamics in the brain indicate that the release of potassium from astrocyte endfeet raises perivascular potassium concentration much more rapidly and to higher levels than does diffusion of potassium through extracellular space, particularly when the site of a potassium increase is some distance from the vessel wall. On the basis of this finding, it is proposed that the release of potassium from astrocyte endfeet plays an important role in regulating regional cerebral blood flow in response to changes in neuronal activity. 相似文献
19.
Blood pressure and cardiac output decline as ambient temperature rises in birds acclimatized to both seasonal- and induced-temperature changes, in contrast to the response usually observed in unacclimatized mammals. The decline in chickens is due to a lowered vascular resistance and blood volume. These circulatory adjustments may be related to the fact that excess heat in birds is dissipated through the respiratory system rather than through the skin. 相似文献
20.
Recovery of neuronal function after prolonged cerebral ischemia 总被引：3，自引：0，他引：3
Cats were submitted to complete cerebral ischemia by clamping the innominate and subclavian arteries and simultaneously lowering the systemic blood pressure. Neuronal function was assessed by recording the electroencephalogram and the anti- and orthodromic activation of the pyramidal tract. A full recovery of the pyramidal response and even of evoked electroencephalographic activity occurred after ischemia of more than 1 hour's duration. 相似文献