Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Observation of brain edema formation after acute drug-induced arterial hypertension-investigation in 15 cats. Intravital staining with astraviolet-FF and Evans-blue showed two different types of BBB-dysfunction, the one diffuse and without protein extravasation, the other multilocular and protein-rich, both localized in the cortical grey matter during the first 5 min after beginning of hypertension. The formation of protein-rich extravasation appeared to be dependent on the percentage increase of blood pressure, less on the peak of its absolute value.
 ...
PMID:Brain edema in acute arterial hypertension. I. Macroscopical findings. 85 52

Studies of blood volume (Evans blue), haematocrit, arterial blood and central venous pressure (CVP) were performed in 37 patients aged 61 to 80 years, 15 h (time I) and 15 min (time II) before, and 20 min after (time III) induction of neuroleptanalgesia (NLA) with fentanyl 0.004 mg and droperidol 0.2 mg per kg body weight. The patients underwent total hip arthroplasty for degenerative joint disease. 11 male and 11 female patients had no other medical disorders ("normal" group). 6 had considerable obesity and 9 had hypertension. The mean blood volume was lower in the female patients in comparison with the male patients and lower in the obese and hypertensive patients in comparison with the "normal" subjects. Between time I and II there was little decrease of blood and plasma volume and increase of haematocrit in the "normal" group. In the hypertensive patients the reverse was true. During this time the mean blood pressure decreased in the hypertensive patients only. CVP remained unchanged in each group. Between time II and III blood pressure and CVP decreased in all groups studied. A haemodilutional effect of NLA expressed by significant decrease of haematocrit and increase of blood and plasma volume was observed in each group. After induction of NLA we found a close correlation of CVP, systolic and diastolic blood pressure with blood volume. These observations firmly suggest that NLA expands vascular capacity. Consequently NLA may lead to a marked fall of blood pressure in hypovolaemic patients. This is important, particularly in hypertensive patients who usually have low blood volumes.
 ...
PMID:[The influence of neuroleptanalgesia on blood volume and circulatory pressures (author's transl)]. 88 68

Acute hypertension was induced by metaraminol at different time intervals following irradiation in rabbits exposed to unilateral X-ray irradiation against the brain (3000 R) and in control animals. Hypertension resulted in a few areas of Evans blue extravasation in control animals. In the irradiated animals there was a marked increase in tracer extravasation on the half of the brain exposed to X-rays, indicating an increased vulnerability of cerebral vessels to blood pressure increase after irradiation.
 ...
PMID:Blood-brain barrier lesions in acute hypertension in rabbits after unilateral X-ray exposure of brain. 109 86

This study is concerned with blood pressure behavior in young adults (aged 15 to 29 years) in the biracial community of Evans County, Ga., on two occasions 7 years apart. On the basis of casual blood pressure recordings the prevalence of systolic pressure equal to or greater than 140 mm Hg or diastolic pressure equal to or greater than 90 mm Hg, or both, showed race/sex differences as follows: white males 19.0 percent, white females 12.7 percent. black males 34.0 percent, black females 31.6 percent. Similar differences were noted in the incidence during the 7 year interval. The problem presented by the variability of the casual blood pressure recording is apparent in this interval study. Of particular interest is the association of weight with blood pressure in this youthful group, particularly among white males and females and black females, in relation to both initial and subsequent pressure levels. The data suggest that in this population under 30 years, weight is a risk factor for hypertension, and that maintenance of ideal weight, instituted in youth, may be a preventive measure.
 ...
PMID:Influence of race, sex and weight on blood pressure behavior in young adults. 111 3

In 1961, blood pressure was measured in the 40-69-year-old segment of the population of Evans County, Georgia. Mortality was monitored for up to ten years. The relationship found between hypertension and mortality is characterized in this report by four parameters: attributable risk, prevalence, population attributable risk, and population attributable fraction. Attributable risk of death, a measure of the over-all impact of hypertension on those in each race-sex group with hypertension, is high in white males, black males, and black females, and is lowest in white females. Population attributable risk, a measure of the impact of hypertension on each entire race-sex group, is highest in black males and females due to the high prevalence of hypertension in blacks. It is somewhat lower in white males and lowest in white females. The fraction of all deaths attributable to hypertension (population attributable fraction) is highest in black females and lower in the other three groups. The population attributable fraction (ranging from 0.26 to 0.54 for systolic hypertension) is of such magnitude that if the 50% reduction in mortality achieved in the Veteran Administration Cooperative Study could be repeated in the general population, life expectancy after 40 years of age could be substantially increased.
 ...
PMID:Attributable risk, population attributable risk, and population attributable fraction of death associated with hypertension in a biracial population. 117 73

Acute hypertension, experimentally induced by intravenous injection of metaraminol in adult rabbits, rapidly induced a damage of the blood-brain barrier in the cerebral cortex, as visualized by Evans-blue-conjugated albumin and horseradish peroxidase. Extravasation of these two exogenous tracers was demonstrated to occur in arterioles, in capillaries and, rarely, in venules. Peroxidase passed the endothelial cell into the nervous tissue in either or three different ways, i.e. through channels, often sigmoidshaped, in the cytoplasm, and transendothelial pinocytosis. The third pathway could, although rarely, be demonstrated between adjacent endothelial cells after cleavage of junctional complexes. The tracer peroxidase was further spread along the blood vessel within the basement membrane and in the extracellular space of the brain. Damaged endothelial cells with diffuse cytoplasmic peroxidase activity and large vesicles were occasionally observed within the areas with blood-brain barrier injury. There were also signs of increased pinocytotic activity in endothelial cells outside the barrier damaged cortical areas. Nerve cells and neuroglial cells could show either a diffuse cytoplasmic peroxidase activity or a vesicular location of the tracer, or sometimes both. The observations are discussed in relation to previous studies on the mechanism of transendothelial passage of protein tracers at blood-brain barrier damage.
 ...
PMID:Ultrastructural studies on cerebrovascular permeability in acute hypertension. 118 1

The cervical sympathetic chain on one side was stimulated electrically at 10-20 Hz and an acute rise in arterial blood pressure was produced by: intravenous injection of angiotensin, ligation of the thoracic aorta, or ligation of the aorta combined with injection of metaraminol. The blood flow through the cerebrum and the cerebellum was determined by using labelled microspheres. At high blood pressures there was multifocal breakdown of the blood-brain barrier in the cerebrum as indicated by leakage of Evans blue. The breakdown was restricted to the control side or much more marked on that side than on the stimulated side. Sympathetic stimulation prevented also breakdown of the blood-aqueous barrier. The blood flow through the cerebrum on the control side was higher than that on the stimulated side in all experiments. Regions with breakdown of the blood-brain barrier had flow rates which were about 10 times normal values. Cerebellar blood flow was less affected by the hypertension and did not react significantly to sympathetic stimulation. The results indicate that stimulation of the sympathetic nerves to the brain tends to prevent forced dilatation of the arterioles with a resulting regional overperfusion with blood and breakdown of the blood-brain barrier. It is concluded that one role of the sympathetic nerves supplying the brain is to extend the pressure region with autoregulation in its upper part under conditions of a general increase in sympathetic vasomotor activity.
 ...
PMID:Sympathetic control of cerebral blood flow in acute arterial hypertension. 125 40

Acute hypertension was induced in 19 anesthetized cats by the intravenous administration of angiotensin. The caliber of pial arteries was measured by a television image-splitting technique and local cerebral blood flow by the hydrogen clearance technique. As the blood pressure was increased, pail arterioles constricted and cerebral blood flow remained relatively constant, showing that autoregulation of cerebral blood flow was intact. At mean arterial pressures of more than 170 mm Hg arteriolar dilation appeared. In smaller arterioles (initial diameter less than 100 mum) a segmental dilation (the "sausage'string" phenomenon) frequently preceded uniform dilation. This arteriolar dilation was associated with a marked increase in local cerebral blood flow indicating that the upper level of autoregulation had been breached. In no cat was vasospasm or a decrease in blood flow observed during induced hypertension. Hypertension also caused dysfunction of the bloodbrain barrier since, in 17 out of 19 of the cats examined, there was extravasation of protein-bound Evans blue into brain tissue. In only one of the 19 cats subjected to neuropathological analysis was ischemic brain damage identified and this was restricted to minimal ischemic cell change. The results indicate that severe, induced hypertension in cats produces cerebral arteriolar dilation, an increase of cerebral blood flow, and dysfunction of the blood-brain barrier. These observations may be of importance in understanding the pathogenesis of hypertensive encephalopathy.
 ...
PMID:Effects of acutely induced hypertension in cats on pial arteriolar caliber, local cerebral blood flow, and the blood-brain barrier. 127 3

The hemodynamic and metabolic effects of 11 days of sham (saline) and corticotropin injection were examined in five different strains of rats: Sprague-Dawley, spontaneously hypertensive (SHR), Wistar-Kyoto (WKY), Brattleboro, and Long Evans. Corticotropin significantly increased systolic blood pressure (SBP) compared with sham injection in all strains: final SBP in Sprague-Dawley was 108 +/- 5 mm Hg corticotropin, 94 +/- 4 mm Hg sham; SHR 146 +/- 6 mm Hg corticotropin, 141 +/- 3 mm Hg sham; WKY 117 +/- 3 mm Hg corticotropin, 103 +/- 3 mm Hg sham; Brattleboro 108 +/- 5 mm Hg corticotropin, 93 +/- 2 mm Hg sham; and Long Evans 103 +/- 5 mm Hg corticotropin, 90 +/- 4 mm Hg sham (P less than .001). Corticotropin also produced a decrease in body weight and increases in water intake and urine output. Increases in urine electrolyte excretion were seen in some, but not all strains. The rise in pressure in the Brattleboro rats indicated that vasopressin is not essential for the corticotropin-induced rise in pressure. Blood pressure rises in SHR were not exaggerated. Withdrawal of corticotropin in Sprague-Dawley rats led to rapid reversal of the corticotropin-induced hemodynamic and metabolic changes. Thus, strain does not appear to be an important factor in corticotropin hypertension in the rat, in contrast to deoxycorticosterone hypertension.
 ...
PMID:Corticotropin effects on blood pressure and fluid and electrolyte homeostasis in five strains of rats. 131 27

It is now well established that chronic exposure of rats to cold (5-6 degrees C) induces an elevation of systolic, diastolic, and mean blood pressures and cardiac hypertrophy within 3 weeks. Since rats of the Long-Evans (LE) strain are known to be resistant to the induction of deoxycorticosterone salt induced hypertension, their cardiovascular responses to chronic exposure to cold were compared with those of rats of the Sprague-Dawley (SD) strain. The results of these studies revealed clear differences between the LE and SD strains of rats. Thus, rats of the SD strain had a significant elevation in their blood pressure; a significantly increased urinary output of norepinephrine and epinephrine; a significantly greater dipsogenic responsiveness to acute administration of angiotensin II, and significant increases in weights of the heart, kidneys, adrenals, and brown adipose tissue compared with their warm-adapted controls. All of these changes are characteristic of rats acclimated to cold. In contrast, rats of the LE strain appear to be less responsive to cold in that blood pressure failed to rise as sharply and to attain as high a level. Furthermore, urinary outputs of norepinephrine and epinephrine were significantly lower in cold-treated rats of the LE strain compared with cold-treated rats of the SD strain, but dipsogenic responsiveness to angiotensin II was unchanged. Although increases in the weight of the previously mentioned organs were also observed in cold-treated rats of the LE strain compared with their warm-adapted controls, weights of the heart and interscapular brown adipose tissue of both groups were significantly less than those of counterparts of the SD strain.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Hypertension during chronic exposure to cold: comparison between Sprague-Dawley and Long-Evans strains. 142 12


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>