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

Blood flow of transplanted intracerebral rat gliomas was measured before and after a constant I.V. infusion of angiotensin II-induced arterial hypertension using hydrogen clearance method. The brain tumor model was produced in syngeneic Wistar-King-Aptekman male rats by stereotaxic inoculation of ethylnitrosourea-induced glioma cells (KEG-1). Induced hypertension by angiotensin II infusion resulted in a significant increase in tumor blood flow compared with control levels (P less than 0.001). In addition, the therapeutic effect of administration of 3-[(4-amino-2-methyl-5-pyrimidinyl) ethyl] -1-(2-chloroethyl)-1-nitrosourea (ACNU) during angiotensin II-induced hypertension was evaluated. At 12 days after implantation, tumor-bearing rats were administrated angiotensin II as the mean blood pressure reached 150 mmHg, followed by ACNU injection, maintained the same blood pressure for 20 minutes. ACNU with induced hypertension group showed a median survival time of 27.0 days, which was significantly (P less than 0.02) longer than that of ACNU alone (22.0 days). It is therefore suggested that chemotherapy with angiotensin II-induced hypertension has a enhancing effect on chemotherapy for improving the drug delivery to tumor tissue by a increased tumor blood flow.
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PMID:[Experimental studies on induced hypertension chemotherapy of intracerebral inoculated gliomas in rats]. 346 30

The presence of angiotensinogen messenger RNA (mRNA) was assessed in total RNA extracted from hepatoma, glioma, neuroblastoma, and glioma-neuroblastoma hybrid cell lines. Total RNA from 1 X 10(7) cells was extracted, transferred to a membrane, and hybridized with a 32P-labeled, full-length (1650-base pair) rat angiotensinogen complementary DNA (cDNA). Angiotensinogen RNA sequences could be definitively detected only in hepatoma cells. Steroids were used in an attempt to increase the angiotensinogen mRNA level. Dexamethasone (2 X 10(-6) M) or 17 beta-estradiol (1 X 10(-7) M) was added to the cultures 18 to 24 hours prior to harvest. Dexamethasone treatment of the hepatoma cells resulted in a large increase in angiotensinogen mRNA, whereas estradiol had no effect. Steroids failed to induce detectable levels of angiotensinogen mRNA in total RNA from the other cell lines. That the RNA was intact was ensured by hybridizing duplicate Northern blots to a 32P-labeled actin cDNA. Actin mRNA sequences were detected in all cell lines. Blot hybridization of poly(A)+RNA resulted in the visualization of a weak angiotensinogen mRNA signal for a glioma cell line and a glioma-neuroblastoma hybrid line. However, the ability to detect angiotensinogen mRNA in a cell may depend on the phenotype expressed, which can be governed by culture conditions.
Hypertension 1987 Jun
PMID:Presence of angiotensinogen messenger RNA in various cultured cell lines. 359 87

Five cases of brain-stem hematoma are described. The cause of these hematomas was identified as "cryptic angioma" (1 cavernous angioma, 1 telangiectasia, 3 arteriovenous malformations). So, they are so-called "secondary hematoma", as opposed to brain-stem hematoma in relation with hypertension. Such secondary hematomas are reported in the literature: 37 operated on cases and 22 untreated cases were found. The clinical picture does not seem to be typical. The presentation appears to be either with the acute onset of a stroke, or with a subacute onset including relapsing symptoms. A progressive deterioration suggesting a pontine glioma or mimicking demyelination is not rare. The CT scanner appearance is often characteristic showing a high density area in the brain-stem which enhanced after injection of contrast medium with an aspect of "halo". Angiography is usually negative. The natural history of brain-stem hematoma due to rupture of a cryptic angioma is not well documented, but it seems that prognosis is very poor. So, the authors insist on surgical evacuation which is effective and safe allowing the diagnosis of brain-stem hematoma and in some cases the identification of the malformation.
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PMID:[Secondary hematoma of the brain stem. Apropos of 5 cases]. 376 36

To determine the risk of intracranial hemorrhage in patients with malignant gliomas who are treated with anticoagulant drugs for late postoperative venous thromboembolism, the authors retrospectively reviewed the computerized data base of all patients with primary brain tumors seen at the University of California, San Francisco, over a 9-year period. Of 915 patients 18 years of age or older who had a pathological diagnosis of malignant glioma and an initial Karnofsky performance scale score of 60% or higher, 36 (4%) developed venous thromboembolism 6 to 246 weeks postoperatively and 22 were treated with anticoagulant drugs. Anticoagulant therapy usually consisted of intravenous heparin for 7 to 10 days, followed for at least 3 to 6 months by either subcutaneous heparin (5000 to 8000 U twice daily) or oral warfarin. All patients were closely monitored to ensure control of hypertension, compliance with therapy, maintenance of prothrombin time within the therapeutic range, and early recognition of adverse side effects. No patient had an intracranial hemorrhage. Thus, anticoagulant agents can be safely administered after intracranial operations for malignant gliomas without increased risk of morbidity or mortality if the patients are carefully monitored according to established guidelines.
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PMID:Risk of intracranial hemorrhage in glioma patients receiving anticoagulant therapy for venous thromboembolism. 381 30

8 cases of cavernous haemangiomas operated and histologically proven are presented. 5 patients (5/8) were admitted because of epileptic seizures, one patient (1/8) because of pure headache, another one because of a focal neurological defect and the last because of intracranial hypertension. Computed axial tomography is a sensitive procedure for detection of cavernomas. Of 7 cases examined by this technique, 7 (7/7) have shown a well circumscribed round or oval hyperdense nodule, with calcifications in 6/7 cases, a slight surrounding oedema in 3/7 cases and without mass effect, except if there is a visible hematoma at operation (2/8). After contrast administration, 5/7 malformations were enhanced and 2/7 displayed draining veins, a fact that we underline. The differential diagnosis includes a low grade calcified glioma, a thrombosed arterio-venous malformation, a venous angioma or an intracerebral hematoma. Surgical excision is the best treatment of these vascular malformations that bleed frequently, and improved all the patients in this series (8/8).
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PMID:[Intracerebral cavernous angiomas]. 408 98

The case of a 58-year-old white man with a history of high blood pressure and chronic obstructive pulmonary disease who developed double vision followed by right-sided facial paralysis is reported. A computerized axial tomogram (CT) scan showed an enhancing lesion in the pontine tegmentum, and the diagnoses of pontine glioma or hemorrhage were considered. Physical findings were limited to the cranial nerves. Conservative management with Decadron for 3 weeks resulted in a prompt clinical improvement, and a CT scan 1 month later showed resolution of the lesion, effectively ruling out a glioma. Total clinical recovery occurred at the end of 6 months. To our knowledge this is the first report of a case of Fisher one-and-a-half syndrome with facial paralysis correlated with computed tomography.
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PMID:Pontine hemorrhage causing Fisher one-and-a-half syndrome with facial paralysis. 622 96

Twenty years ago it was demonstrated that angiotensin II (Ang II) acts on the brain, which results in an elevation of blood pressure. Ten years later, reninlike activity was discovered in the brain of the rat and dog, which gave rise to the concept of an endogenous brain renin-angiotensin system. In the periphery, the kidney, liver, and lungs work in unison to produce Ang II. Evidence for brain renin, substrate, converting enzyme, and angiotensins is reviewed. New data indicate that the enzyme system for the synthesis of Ang II within the brain may in fact be contained in the cell. All the components for a renin-angiotensin system have now been found in neuroblastoma/glioma cell lines and Ang II is present in primary cell culture of rat brain neurons. The significance of angiotensin in the brain for hypertension is that it may be a stimulus for vasopressin release and sympathetic activation, which can maintain high blood pressure. In the spontaneously hypertensive rat, there is evidence of increased brain angiotensin. Also, experiments with angiotensin-converting enzyme inhibitors show that blockade of brain angiotensin production leads to a long-lasting lowering of blood pressure. The activity of the inhibitors in part appears to be directly on the brain.
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PMID:New evidence for brain angiotensin and for its role in hypertension. 630 29

In normal brain, the blood-brain barrier (BBB) is highly impermeable to K+ cations, their transport being controlled by ATPases situated in the endothelial cell membranes. 82Rb+ is a positron-emitting analogue of K+ with a half-life of 75 s. Using a steady-state model and positron emission tomography, quantitative extraction data for 82Rb+ transport across the BBB have been obtained both in normal human subjects and in a variety of conditions of cerebral pathology. A mean cerebral Rb extraction of 2.1% was found for normal subjects, corresponding to a mean value of 1.1 x 10(-6) cm s-1 for 82Rb+ cation permeability across the BBB. No increase in cerebral Rb extraction was observed for patients with diffusely raised intracranial pressure secondary to obstructive hydrocephalus and benign intracranial hypertension, or for patients with multiple sclerosis or cerebral systemic lupus erythematosus. Cerebral tumours that were enhanced on computed tomography scanning showed a significant increase in local Rb uptake. No correlation between tumour size, or grade of glioma, and tumour Rb extraction was found. Nonenhancing tumours showed no increase in local Rb extraction, and regions of perifocal tumour oedema also had Rb extraction values in the normal range. It is concluded that increased Rb extraction occurs only where tight junction integrity in the BBB breaks down locally, that is, in the microcirculation of enhancing tumours but not in that of perifocal regions of tumour oedema or nonenhancing tumours.
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PMID:Quantitative measurement of blood-brain barrier permeability using rubidium-82 and positron emission tomography. 633 92

This review deals with steroid hormones and receptors in relation to the physiology and the pathology of the central nervous system (CNS) and meninges. In recent years experiments performed in animals showed that: 1) endogenous steroid hormones cross the blood brain barrier: 2) radiolabelled steroid hormones bind in specific areas of the CNS; 3) all five classes of steroid receptors, i.e. oestrogen, progesterone, androgen, glucocorticoid and mineralocorticoid receptors (OR, PR, AR, GR, MR), are present in brain tissues, especially in the hypothalamus and the limbic system; 4) the interaction of steroid hormones and specific receptors induces the synthesis of proteins in the CNS; 5) finally, in situ metabolism of steroid hormones has been evidenced by the presence of specific enzymes. A few studies in human brain tissues have shown the presence of GR and OR as well as enzymes involved in the metabolism of sex steroid hormones. In neurology, some epidemiological and clinical data suggest the implication of steroid hormones and receptors in human CNS: 1) the influence of oestrogens in tardive dyskinesia; 2) the relevance of hormonal changes in benign intracranial hypertension; 3) the usefulness of glucocorticoid therapy in many patients with intracranial tumors and/or edema. Due to feasibility, most researches have concerned tumors: meningioma, neurinoma and glioma. Firstly, a reappraisal of biochemical and histochemical technics used to detect and characterize the receptors in tumors is presented. Then results from the recent literature are reviewed. In meningioma, PR was found in 89 p. 100 (152/177) of the cases, usually at moderate to high levels (up to 33 000 fmol/gT). In addition, PR has been fully characterized from a biochemical point of view. Furthermore, it has been hypothesized that PR may be a marker of leptomeningeal cells since it was detected at high levels in well differentiated tumors provided they had no or few psammoma. This was further supported by the discovery of PR in normal leptomeninges in human adults. OR was detected in 48 p. 100 (87/177) of the meningioma, at low levels. This is in contrast with PR but the percentage of cases with OR raises to 70 p. 100 (42/60) if one considers only tumors assayed for both cytosolic and nuclear receptors. Therefore it has been suggested that OR had translocated into the nucleus, at least in some cases, and subsequently the hypothesis of functional OR in meningioma was raised. AR was also detected in meningioma. Furthermore AR levels were found to correlate well with PR levels.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:[Steroid receptors in the central nervous system. Implications in neurology]. 637 95

The work was concerned with the study of 57 gliomas, among which were 30 glioblastomas, 20 astrocytomas, and 7 oligodendrogliomas. Specimens collected from 26 patients who underwent operation for severe craniocerebral trauma, meningioma, and carcinoma metastasis were examined as controls. The proteins of the tumor tissues and those of the brain matter surrounding the tumor and of normal brain matter were fractionated in polyacrylamide gel. It was found that the amount of water soluble protein, both in the total protein content and in all its fractions, was much greater in the glial tumors than in normal brain matter. The effect of 11 factors on the tissue protein composition was studied by factor analysis. The histological structure and extent of vascularization of the tumor as well as the presence of intracranial hypertension were found to produce the highest effect on the fractional distribution of the proteins.
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PMID:[Relation between the protein composition of glial tumors and various clinico-morphologic indices]. 649 54


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