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Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We investigated cerebral blood flow and metabolism, and cerebral vascular response in 9 patients with cerebrovascular Moyamoya disease or unilateral Moyamoya phenomenon using positron emission tomography (PET). The subjects consisted of 5 men and 4 women, and were from 9 to 60 years old. Five patients had bilateral occlusion in the carotid fork with Moyamoya vessels (fulfilled the criteria of cerebrovascular Moyamoya disease), and four patients had unilateral Moyamoya phenomenon. The PET scanner used was the HEADTOME III, of which spatial resolution in clinical use was 10 mm full width at half-maximum (FWHM) in the image plane. Cerebral blood flow (CBF), cerebral metabolic rate of oxygen (CMRO2), cerebral oxygen extraction fraction (OEF), and cerebral blood volume (CBV) were measured in resting state by the 15O-labelled gases steady state method in every patient and 22 normal controls (17 men and 5 women, and from 26 to 64 years old). Consecutively cerebral vascular responses were measured by H215O autoradiographic method in resting state, hypercapnia, hypocapnia, and hypertension. Forced hypercapnia, hypocapnia, and hypertension were achieved by 7% CO2 inhalation, hyperventilation, and venous infusion of angiotensin II, respectively. CMRO2 of the whole brain was significantly lower in patients than in normal controls (p less than 0.05), and CBV of the lentiform nucleus significantly increased in patients (p less than 0.01). This reflected Moyamoya vessels in the basal ganglionic regions. In 3 of 5 patients with bilateral Moyamoya vessels, CBF and CMRO2 in the symptomatic cerebral hemisphere were lower than that in the nonsymptomatic hemisphere.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Vascular responses in cerebrovascular "Moyamoya" disease--evaluated by positron emission tomography]. 251 9

We studied the therapeutic action of CO2 Laser on leg ulcers due to chronic venous hypertension in 30 subjects. Our findings show good results in reducing pain and leg oedema and wound healing.
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PMID:[Defocused CO2 laser in the treatment of leg ulcers. Preliminary results]. 251 23

Morphology of the carotid body and the ventilatory response to hypoxia were compared in New Zealand genetically hypertensive rats and 'normotensive' control rats from the same genetic stock. Hypertensive rats grew more slowly, had higher blood pressure from 6 weeks of age and developed left ventricular hypertrophy. Carotid bodies of both groups were similar in size but larger than those of a common Wistar strain. Intimal damage and proliferation were seen in 1st- and 2nd-order branches of the carotid body artery in hypertensive rats and point-counting showed that the volume proportion of Type 1 cell nuclei and vascular lumen was reduced and vascular wall increased. In age-matched anaesthetized rats, minute ventilation per 100 g was greater in hypertensives than 'normotensive' when inspiring O2 concentrations of 30, 21, 18, 15, 12, 10 and 8%. However, at each inspired O2 concentration, arterial Pa.O2 was higher and Pa.CO2 lower in hypertensive than in 'normotensive' rats. Hypertensive rats were hyperventilating. The shape of the ventilation/O2 tension curve was similar in hypertensive and 'normotensive' rats; thus carotid body sensitivity to hypoxia was probably unchanged. Possible causes of hyperventilation and the relation of carotid body morphology to hypertension are discussed.
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PMID:Structure and function of the carotid body in New Zealand genetically hypertensive rats. 253 3

The integrity of the blood-brain barrier (BBB) was examined in rabbits, in terms of the partition of 99mTc-pertechnetate (99mTcO4-) between brain and blood, following intracarotid injection of hypertonic arabinose, hypertension (168 mm Hg and 10% inspired carbon dioxide), or hypotension (less than 20 mm Hg for 15 min). Corrections were made for changes in tissue blood contents, using chromium-51 as a red cell marker. In control animals the mean brain:blood ratio was 0.038 (range 0.027-0.052). Following arabinose there was a five-fold increase in mean BBB permeability (mean brain:blood ratio 0.192 (0.070-0.378)). There was no change after hypertension and carbon dioxide (mean ratio 0.034) or after hypotension (mean ratio 0.032), despite an increase in cerebral extracellular potassium. Examination of other tissues showed no change in the 99mTcO4- tissue/blood partition in heart muscle in any study but, following hypotension, ratios in the kidney (mean ratio 1.63) and, to a lesser extent, the liver (mean ratio 1.37) had increased, suggesting an abnormality of active transport under these conditions. We conclude that, while 99mTcO4- tissue/blood partitioning revealed osmotic disruption of the BBB, profound hypotension with evidence of brain cell damage did not change BBB permeability to the same marker. Hypotension may influence active transport of this ion in liver and kidney.
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PMID:Blood-brain barrier to pertechnetate following drug-induced hypotension. 253 49

Up to now, no studies have been performed in normal humans to investigate the role of renal hemodynamic abnormalities in relation to acute-cyclosporin A (CsA) renal dysfunction and to verify whether the specific renal vasodilator, dopamine, can counteract these abnormalities. Eight normal subjects were examined both (A) after oral CsA (12 mg/kg body wt) and (B) after oral CsA + dopamine infusion (2 mg/kg body wt/min), under water diuresis. Both in protocols A and in B, four basal renal clearances were performed before CsA and every twenty minutes for four hours after CsA administration. In protocol A, after CsA, inulin (GFR) and PAH clearance (RPF) fell by up to 27% and to 41%, respectively, so that filtration fraction (FF) increased (P less than 0.01). A slight (not significant) hypertension occurred while renal resistances were markedly raised (P less than 0.001). Fractional urine and Na+ excretion as well as CH2O decreased, while UOsm increased (P less than 0.01). In protocol B, dopamine was infused from 120 to 180 minutes after CsA (that is, when the maximal adverse effects of CsA on renal hemodynamics had been observed in A). Dopamine infusion could reverse completely the effects of CsA on RPF, GFR, fractional urine output and CH2O; only UOsm remained higher than normal in conclusion with an increased fractional excretion of sodium (P less than 0.01). No changes were observed in plasma renin activity, aldosterone and in urinary epinephrine and norepinephrine excretion both in protocols.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Acute cyclosporine renal dysfunction reversed by dopamine infusion in healthy subjects. 260 Dec 57

Twenty-five samples of amniotic fluid obtained by amniocentesis from 25 pregnant women with hypertension in the 35 to 40 weeks of pregnancy were studied. The following biochemical determinations were done in the samples: acid-base equilibrium (pH, pO2, pCO2, base deficit, standard HCO3- and total CO2), concentrations of potassium and sodium ions, total and ionised calcium and inorganic phosphorus. The results were analysed depending on the presence of the respiratory distress syndrome in the newborn, and were subjected to statistical analysis. It was found that determination of acid-base equilibrium and concentrations of K+, Na+, total and ionised Ca++ and inorganic phosphorus in the amniotic fluid of hypertensive women are probably without prognostic significance with respect to the development of the respiratory distress syndrome in newborns.
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PMID:[Respiratory distress in newborns born to hypertensive mothers and acid-base equilibrium and the ion composition of the amniotic fluid]. 270 90

Acute hypoxemia results in hypertension, bradycardia, and cardiac output redistribution in fetal sheep. The blood flow redistribution is produced by differential changes in vascular resistance of various fetal organs. alpha-Adrenergic activity is one of the few vasoconstrictor mechanisms thus far identified in the hypoxemic fetal sheep. Arginine vasopressin (AVP) is a potent vasoconstrictor in adults. Since AVP administration to the normoxic fetus mimics some of the fetal cardiovascular responses to hypoxemia and fetal plasma AVP levels increase with hypoxemia, we examined the hypothesis that AVP modifies the fetal cardiovascular response to hypoxemia by changing the vascular resistance of some fetal vascular beds. To test this we determined fetal systemic arterial pressure and fetal cardiac output and its distribution during hypoxemia with and without the V1 AVP antagonist d(CH2)5-Tyr(Me)AVP. Fourteen fetal sheep (0.79-0.90 of gestation) were chronically catheterized. Five days after surgery fetal hypoxemia was induced by introducing a mixture of 95% N2-5% CO2 (10-20 l/min) into a maternal tracheal catheter. The hypoxemia was maintained for 40 min. Fetal heart rate, systemic arterial blood pressure, and combined ventricular output and its distribution (radiolabeled microspheres) were measured before hypoxemia, at 20 min of hypoxemia alone, and at 20 min of hypoxemia plus either AVP antagonist (n = 5) or NaCl 0.9% (n = 5, controls). Fetal hypertension and bradycardia were partially reversed after the AVP antagonist administration during hypoxia.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Arginine vasopressin mediates cardiovascular responses to hypoxemia in fetal sheep. 271 44

In developed countries, hypertension represents one of the most frequent diseases and is one of the most important risk factors of arteriosclerotic vascular disease e.g. to myocardial infarction or cerebral apoplexy. The etiology of hypertension is unknown in about 90% of cases. The heavy metals cadmium and lead occur in increasing amounts in the human environment. Numerous epidemiological studies and investigations using experimental animals have dealt with the putative relationship between cadmium and lead, and hypertension. The results to date have been quite controversial; thus the issue appears to be unresolved at present. In the present study scalp hair samples were collected from 100 non-smoking 30-to-50-year-old men. After washing, the samples were digested with a mixture of nitric and sulfuric acid in a teflon bomb and analyzed by flameless atomic absorption spectroscopy. For 90% of the test persons the cadmium hair values were in the range of 0 to 1400 micrograms/kg; the corresponding range for hair lead was 0 to 13,000 micrograms/kg. Correlation with diastolic or systolic blood pressure was neither found for cadmium or lead. The test persons with the highest cadmium or lead load were not hypertensive. Some factors should be considered when comparing the present results with those of other investigators reporting a positive correlation in the question under consideration. 1. Previous studies in man frequently did not sufficiently take smoking habits into account. This is essential, however, because, in addition to cadmium and lead, nicotine and carbon monoxide are also constituents of tobacco smoke and contribute to an increase in blood pressure. 2. Previous investigations generally employed blood samples, which is disadvantageous in comparison with the analysis of hair because blood samples do not reflect long-term exposition, which is important in the etiology of chronic diseases. Correlation between hypertension and levels of long-term cadmium and lead exposure in man seem to be unlikely in light of the present results. Nevertheless, numerous potential effects should be considered to obtain further insight in the complex pathogenesis of hypertension.
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PMID:[Correlation of blood pressure and cadmium and lead content of the hair in nonsmoking males]. 275 43

We compared intraosseous pressure, partial pressure of oxygen and carbon dioxide, and histopathology in 10 hips with arthrosis and in seven hips with nontraumatic necrosis of the femoral head. Hypoxia of the subchondral bone was present in both conditions. In arthrosis the intraosseous pressure was normal, whereas intraosseous hypertension was present in necrosis. Partial pressure of carbon dioxide was normal in both conditions. Identical signs of subchondral medullary and trabecular necrosis were found in both conditions.
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PMID:Intraosseous pressure, oxygenation, and histology in arthrosis and osteonecrosis of the hip. 281 18

We compared exercise responses in two groups of hypertensive patients treated with an angiotensin converting enzyme (ACE) inhibitor (lisinopril, 20-80 mg/day, n = 17) or a cardioselective beta-blocker (atenolol, 50-200 mg/day, n = 9). Measurements were made at rest and during exercise at 25 W (2.7 mets) and at 50 W (3.8 mets) on a bicycle ergometer (where mets is exercising oxygen consumption/resting oxygen consumption) after 4 weeks of placebo, and again after 12 weeks of drug administration. Both drugs reduced (P less than 0.05) mean arterial pressure. Atenolol caused significant decreases in the heart rate (approximately 25%) and cardiac output (approximately 26%; Defares CO2 rebreathing), and significant increases in total peripheral resistance (approximately 30%) and arteriovenous O2 content (approximately 20%). Lisinopril decreased (P less than 0.05) stroke volume. At the same exercise intensity systolic blood pressure, arteriovenous O2 and total peripheral resistance were lower (P less than 0.05) and the heart rate was higher (P less than 0.05) after lisinopril than after atenolol. After the treatment of hypertension with the ACE inhibitor the responses to exercise were less restrictive than those after treatment with the cardioselective beta-blocker.
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PMID:Effects of angiotensin converting enzyme inhibition and beta-blockade on exercise responses in hypertensive patients. 285 65


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