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

A prolonged experimental situation of focal vasogenic oedema, producing mild intracranial hypertension, was developed. The aim was to study the immediate and long-term effects of repeated infusions of mannitol and glycerol on intracranial pressure (ICP) and cerebral blood flow (CBF). Eighteen goats were operated on twice to implant: an epidural latex balloon in each cerebral hemisphere to measure ICP; an electromagnetic flowmeter around both internal maxillary arteries (the only cerebral blood input), after tying the extracranial branches, to measure the CBF; and two femoral catheters to measure blood pressure (BP) and for intravenous infusion (IV). Three groups of 6 goats each were formed: A) control; the BP and bilateral ICPs and CBFs were recorded under basal conditions and every 4 hours for 3 days after a cold injury (CI) was provoked; B) 20% mannitol solution 1 g/kg body weight injected every 12 hr starting at 24 hr post-CI; and C) 10.1% glycerol solution 0.5 g/kg body weight, administered as mannitol. Glycerol, as compared to mannitol, presents the following major differences among its immediate post infusion effects: a lesser decrease in ICP, but no rebound phenomenon; lesser elevation of BP; CBF increases more gradually and constantly. Long-term effects with mannitol consisted of a rebound phenomenon observed in ICP during the last 12 hr. In all 3 groups, it was observed that CBF increases in relation to the ICP level.
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PMID:The immediate and long-term effects of mannitol and glycerol. A comparative experimental study. 190 77

Previous studies have shown that essential hypertension is frequently associated with insulin resistance. The tissues responsible for this metabolic alteration have not been defined. We tested the hypothesis that skeletal muscle is the site of insulin resistance of essential hypertension with the use of the perfused forearm technique. Eight hypertensive (age 42 +/- 3 years, body mass index 27 +/- 1 kg/m2, intra-arterial mean blood pressure 126 +/- 4 mm Hg) and seven normotensive (age 48 +/- 3 years, body mass index 26 +/- 1 kg/m2, mean blood pressure 95 +/- 4 mm Hg) male volunteers were studied. After glucose ingestion (40 g/m2), normal glucose tolerance in the patients was maintained at the expense of a heightened plasma insulin response, suggesting the presence of insulin resistance. During graded, local (intra-arterial) hyperinsulinemia encompassing the physiological range (12-120 milliunits/l), glucose uptake by forearm tissues was significantly (p less than 0.03) reduced in the hypertensive subjects as compared with the controls at each of five insulin steps, by 43% on the average. In addition, forearm lactate and pyruvate release were significantly less stimulated in the hypertensive than in the normotensive group (p less than 0.01 for both), presumably as a consequence of the decreased glucose influx. Forearm exchange of oxygen, carbon dioxide, lipid substrates (free fatty acids, glycerol, and beta-hydroxybutyrate), and potassium were similar in the hypertensive and normotensive groups in the basal state. Insulin had no effect on oxygen consumption, carbon dioxide production, and respiratory quotient in either study group, whereas it stimulated free fatty acids, glycerol, and potassium uptake to the same extent in the hypertensive and normotensive groups.(ABSTRACT TRUNCATED AT 250 WORDS)
Hypertension 1991 Feb
PMID:Impaired insulin action on skeletal muscle metabolism in essential hypertension. 199 49

In various models of hypertension of genetic origin, a hypersensitivity of phospholipase C has been demonstrated to participate in the hyperreactivity of platelets toward a variety of vasoactive agents. Since this abnormality could not be observed in the absence of cell stimulation, it could not account for the increase in free Ca2+ which has been reported in resting platelets in primary hypertension. Likewise, in hypertensive subjects, platelets behave hyperactive when stimulated by ADP, although the stimulus has been demonstrated to be a poor activator of phospholipase C. In order to gain insight into the membrane alteration that could account for the cellular hyperactivity which characterizes hypertensive subjects, we investigated, in resting platelets, the kinetics of radioactive labeling of major membrane phospholipids. Isolated platelets were prepared from SHR (4w and 17w of age), SHR-SP, Dahl salt-resistant and salt-sensitive rats fed either a low or a high salt diet, DOCA-salt hypertensive rats and from the appropriate normotensive controls. Irrespective of the radioactive precursor used (32P-orthophosphate, 3H-glycerol, 3H-choline), the labeling of phosphatidylcholine (PC) was markedly (up to 20 fold) enhanced in SHR (whichever their age) and SHR-SP compared with WKY. This increase, specific of PC, could not be accounted for by differences either in the actual amount of PC or in the uptake of various labels, suggesting an increased PC turnover. Such an increase was also observed in platelets of Dahl hypertensive rats but not in those of DOCA-salt hypertensive rats.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Membrane abnormalities and cellular hyperreactivity in different models of hypertension]. 212 54

Glycerol trinitrate (GTN) was used during anesthesia in angiosurgical patients for the correction of vascular tone in initial hypertension, normalization of cardiac output and retention of compensatory vascular reactions in critical conditions of the circulatory system during inclusion and exclusion of the aorta from circulation. The combination of GTN with calypsol and narcotic analgesics reduces the hypertensive effect of calypsol and tachysystolic effect of GTN.
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PMID:[The use of nitroglycerin in general anesthesia during vascular alloprosthesis]. 212 62

Angiotensinogen messenger RNA (mRNA) has been identified in both brown and white adipose tissue. Recently we have shown that when 3T3-L1 cells were treated with isobutylmethylxanthine (IBMX) to accelerate differentiation, angiotensinogen mRNA increased markedly in adipocytes as compared with preadipocytes. To determine if a correlation existed between the regulatory events associated with the differentiation process, we compared the change in angiotensinogen mRNA in spontaneously differentiating 3T3-F442A cells with two established parameters of differentiation in adipocyte cell lines. Differentiation was assessed by visual examination of cells for lipid droplets, fluorescent staining of the F-actin fibers, and increases in glycerol phosphate dehydrogenase mRNA. F-actin fibers were highly structured in preadipocytes, becoming disassembled and very disorganized as cells differentiated into adipocytes. The quantity of angiotensinogen mRNA increased as the number of lipid-containing cells increased within a culture. Glycerol phosphate dehydrogenase mRNA accumulated in differentiated adipocytes to about the same extent as angiotensinogen mRNA. Thus, increases in angiotensinogen mRNA were associated with the morphological and biochemical changes that occur during the phenotypic modulation of 3T3-F442A cells.
Hypertension 1990 Jun
PMID:Changes in angiotensinogen messenger RNA in differentiating 3T3-F442A adipocytes. 235 37

It has been previously demonstrated that spontaneously hypertensive adult rats (SHR) develop severe hypertension and cerebrovascular lesions on drinking 1% NaCl from weaning and that the phospholipid metabolism in the whole brain is actively altered in these lesioned animals (SHR-NaCl) as compared to SHRs which drink only water and show only sporadic cerebrovascular lesions. We have now assayed the incorporation of labelled choline, ethanolamine, glycerol and arachidonic acid into the phospholipids from the cortex and hippocampus of SHR-water and SHR-NaCl at different time intervals from injection into the lateral ventricle of the brain. A noticeable decrease of both choline and arachidonate specific activity (SA) in the phospholipids was found in the cortex and hippocampus (where the effect is most evident) from SHR-NaCl. Based on the literature and the data obtained, we suggest that in SHR-NaCl brain areas a release of choline and fatty acid also occurs from choline glycerophospholipids as a consequence of the cerebrovascular lesions caused by NaCl treatment. Even if a relatively minor loss of the amount of the lipids studied is evident from our results as compared to their entire pool, this change may be quite important if it causes a modification of the lipidic bilayer in excitable membranes. In a parallel group of SHR-NaCl animals, treated with the nootropic drug oxiracetam, we observed that the metabolic utilization of the precursors was completely restored. These experimental data favour the hypothesis that oxiracetam is effective in stimulating the phospholipid metabolism rate at levels even higher than those of the SHR-water animals.
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PMID:The effect of oxiracetam treatment on alterations of lipid metabolism in brain areas from spontaneously hypertensive rats. 274 13

There are many reports on the disequilibrium syndrome due to dialysis in patients with chronic renal failure. However, they do not mention the findings of CT cisternography and MRI. We intend to investigate the mechanism of CSF dynamics in a patient with disequilibrium syndrome by means of these radiological examinations. A 31 year-old woman who had suffered from renal failure for 18 years was found to have prominent increase of serum creatinine (18.1 mg/dl) and BUN (127 mg/dl) 3 years ago. At that time, digital marking of the skull was already present by X-ray examination without other destruction in bone survey of the whole body. She was hemodialysed by the hollow fiber kidney three times weekly (dialysis time 4.5 hours, dialysate osmotic pressure 270 mOsm/kg H2O). Three months ago, she began to complain of severe headache, nausea and vomiting 2 hours after the beginning of dialysis, so that she was referred to Kosei Hospital. On admission, she showed exophthalmus, concentric narrowing of the visual field, optic atrophy and hyperreflexia in jaw and four extremities. After admission, she received hemodialysis therapy thrice weekly (dialysis time 5 hours, dialysate osmotic pressure 290 mOsm/kg H2O). At the same time, 200 ml of glycerol (contents of glycerin 10, fructose 5, NaCl 0.9%) was administered intravenously during dialysis, which ameliorated the symptoms of intracranial hypertension. Laboratory studies revealed marked decrease of serum creatinine, BUN and uric acid levels and osmotic pressure, and increase of blood pH at the time of postdialysis compared with predialysis. Manometric CSF pressure increased up to 310 mmH2O at the day without dialysis before the glycerol administration.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[A case of chronic renal hemodialysis and intracranial hypertension--a study on CSF dynamics]. 276 3

Bicuculline (either 25 mumol or 12.5 mumol/kg body wt) was administered to rats by intraperitoneal route. Animals treated with 25 mumol/kg experienced convulsions, whereas those receiving 12.5 mumol/kg did not. Controls received saline instead of the drug. Radioactive precursors [2-3H] glycerol and/or [1,2 14C] ethanolamine were injected into cerebral ventriculi simultaneously with bicuculline and the rats were killed 12 min afterwards. Their brains were dissected by hand into four parts (cerebellum, brain stem, hippocampus, cerebral cortex) and the labeling of lipid classes determined after extraction and separation. Although glycerol was incorporated into lipid better than ethanolamine in all areas, the fate of the injected radioactive precursors varied according both to area and treatment. The lowest uptake of radioactivity was in the cerebral cortex and the highest in the brain stem and hippocampus. Moreover, the administration of bicuculline influenced the distribution of radioactivity among lipid classes; these variations, however, were not dependent on the administered doses of bicuculline. We conclude that the effects on glycerolipid metabolism observed in convulsing animals are due to several causes including alterations of systemic parameters (hypertension, hypoxia, etc.). The distribution of glycerol label between phospholipid and neutral lipid is proposed as a biochemical model for the study of convulsive and subconvulsive states.
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PMID:Effect of subconvulsive doses of bicuculline on the incorporation of radioactive precursors into glycerolipids in rat brain areas. 276 41

It has been demonstrated that spontaneously hypertensive adult rats (SHR) develop severe hypertension and cerebrovascular lesions on drinking 1% NaCl from weaning. Phospholipid metabolism is actively altered in these severely lesioned animals (SHR-NaCl) as compared to SHRs which drink only water and showed only sporadic cerebrovascular lesions. We have tested the incorporation of water soluble phospholipid precursors into the corresponding phospholipid from different brain areas, by injecting either a mixture of labeled glycerol and choline or glycerol and ethanolamine into the lateral ventricle of the brain of adult (4 months old) and senescent (12 months old) SHR-NaCl. The results were compared to those obtained from 4 and 12 months old Wistar normotensive rats. When adult normotensive rats were compared with adult hypertensive rats (4-SHR-NaCl) incorporation was found to decrease in some areas according to the precursors injected. Similar results were obtained from 12 month old normotensive Wistar rats that, however, showed a decrease in phospholipid biosynthesis in all the area tested. Interestingly, no significant differences of incorporation rate were found between 12 month old normotensive and 12 month old hypertensive rats.
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PMID:Effect of age and strain on cerebral phospholipid metabolism. 342 6

The present paper describes the use of a quantitative renal vascular casting method to study the changes associated with kidney disease. Several animal models of hypertension (spontaneously hypertensive rat, SHR, with its normotensive rat the Wistar Kyoto, WKY; Dahl salt sensitive DS - hypertensive, and salt resistant DR - normotensive) were examined at time points when the systemic blood pressure was rising (6 and 12 weeks of age) and following renal denervation (in SHR-WKY rats). The SHR appears to have a smaller caliber afferent arteriole at both 6 and 12 weeks of age. This difference is probably not entirely due to sympathetic vasoconstriction since the strain related afferent arteriolar diameter difference was still present after renal denervation. In the Dahl rats, there is not much of an intrarenal vascular difference between the DS and DR rats with the only real finding of a smaller distal afferent arteriolar diameter found in outer cortical nephrons of the DR. The two models of acute renal failure (ARF) that were studied include, the glycerol model (known to initially cause an intense vasoconstriction) and gentamicin, a nephrotoxic antibiotic. Two time points were examined for each of these models. As expected in the glycerol model there was an intense vasoconstriction at three hours which essentially was gone at 3 days - a time when the renal failure was fulminant. The glomerulus appeared to be contracted at three hours as well. In the gentamicin model no renal vascular alteration was seen at 6 days, when renal failure was mild while at 10 days, when renal failure was pronounced, outer cortical afferent arterioles appeared to be moderately constricted. In the 5/6 nephrectomy model of chronic renal failure, the glomeruli were smaller in rats in renal failure than in the controls.
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PMID:Quantitative renal vascular casting in nephrology research. 373 22


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