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

Using noninvasive (echoventriculometry (Echo-VM), REG and invasive (planimetric PEG, graphic recording of the CSF pressure) methods of examination, the authors determined the size of cerebral ventricles and the status of the cerebral hemo- and CSF dynamics in 606 patients with various chronic diseases of the brain (consequences of craniocerebral injury, epilepsy, discirculatory encephalopathy, etc.). According to PEG and Echo-VM findings, two groups of patients were distinguished. In moderate dilatation of cerebral ventricles the most significant finding was an increase in the pulse pressure of the CSF, whereas its mean pressure was normal or slightly elevated. In patients with pronounced hydrocephaly the pulse and mean pressure of the CSF tended to decrease. The progress of hydrocephaly was parallelled by increasing disorders of the cerebral hemodynamics expressed in hindered venous outflow from the cranial cavity and elevated peripheral vascular resistance. Four CSF-related syndromes have been identified (normotension, total CSF hypertension, intraventricular tension, total CSF hypotension) differing in their diagnostic and prognostic significance and in the pathogenesis of disorders of the hemo- and CSF dynamics.
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PMID:[Status of the ventricular system and dynamics of the cerebrospinal fluid changes in chronic brain diseases]. 325 71

A 63-year-old man with arterial hypertension suffered from depression and suicidal wish after a cerebrovascular accident and transitory left hemiparesis. He was urgently admitted to hospital in severe metabolic acidosis which caused renal failure and coma, ending fatally within two days. At necropsy calcium oxalate crystals were found in the renal tubules and cerebral vessel walls with chemically induced meningoencephalitis. From these findings glycol poisoning was diagnosed. There was a lethal concentration of ethylene glycol in the urine. The toxic effects of ethylene glycol are due to its metabolites. The oxalate crystals are primarily of diagnostic importance.
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PMID:[Ethylene glycol poisoning]. 337 4

The charge-associated and non-charge-associated (probably lipid-related) surface properties of erythrocytes from spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKY), from which SHR were originally derived, were studied by cell partitioning in dextran-polyethylene glycol aqueous phase systems. A major difference was found in the surface charge-associated and lipid-related properties of red blood cells from SHR and WKY: the cells from WKY had the higher partition ratio in both charge-sensitive and non-charge-sensitive phases. No difference in partitioning could be found between any two SHR nor between any two WKY. The SHR and WKY erythrocytes showed the same difference when compared with one another even when rats had the same blood pressure. When red blood cells from SHR with different blood pressure were compared, there still was no difference in their surface properties. These results suggest that the differences in both charge-associated and lipid-related surface properties of erythrocytes from SHR and WKY are strain-specific (i.e., genetic) but that there is no correlation, reflected by partitioning, between red blood cell surface properties and the degree of the rats' hypertension.
Hypertension 1986 Jun
PMID:Partitioning of erythrocytes from spontaneously hypertensive and Wistar-Kyoto rats. 371 May 59

Numerous studies have focused on functional vascular changes that characterize the hypertensive state. Recent evidence that suggests that increased vascular reactivity in hypertension is due to changes in the delivery of activator Ca++ through channels in the cell membrane will be reviewed. The primary evidence supporting this hypothesis comes from studies that characterize the effects of Ca++-free solution and calcium channel blockers on contractile properties of isolated vascular smooth muscle. In the present study, experiments were performed to investigate the role of Ca++ influx in vascular contractions produced by interventions that cause membrane depolarization. Isometric tension development in helical strips of carotid arteries from stroke-prone spontaneously hypertensive rats in response to elevated K+ and tetraethylammonium chloride was greater than that in carotid arteries from Wistar-Kyoto normotensive rats. The rate of tension development to K+-free solution in carotid arteries from stroke-prone spontaneously hypertensive rats was faster than in Wistar-Kyoto normotensive rat arteries. Contractile responses to all 3 depolarizing interventions were reduced in arterial strips incubated in Ca++-free solution containing the chelator ethylene glycol bis-(beta-aminoethyl ether) N,N,N',N'-tetraacetic acid and in arterial strips treated with the Ca++ channel blocker verapamil. These results are consistent with the hypothesis that constrictor stimuli that produce membrane depolarization cause an opening of Ca++ channels in the plasma membrane that are sensitive to the organic channel blockers. Further, a change in Ca++ permeability or membrane depolarizing mechanisms contributes to increased contractile responsiveness in carotid arteries of stroke-prone spontaneously hypertensive rats.
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PMID:Calcium influx and vascular reactivity in systemic hypertension. 381 61

In vivo platelet activation by circulating immune complexes has been suggested as one of the underlying mechanisms in preeclampsia. Using a modification of the polyethylene glycol protein-A immune complex assay, immune complexes were found in excess of the equivalent of 20 micrograms/ml heat aggregated IgG in fourteen out of twenty patients diagnosed as having pre-eclampsia. Only six out of nineteen normal controls were found to have similar levels of immune complexes. Furthermore, using a small volume bio-assay method, concentrations of heat aggregated IgG in excess of 20 micrograms/ml were found to activate platelets to release sufficient concentrations of vasoactive agents to constrict a human blood vessel in vitro. These results support the hypothesis that in vivo platelet activation by immune complexes can release sufficient concentrations of vasoactive agents to contribute to the hypertension characteristic of pre-eclampsia.
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PMID:Immune complexes and vasoactivity generated from platelets in pre-eclampsia. 621 32

Eighteen patients with pre-eclampsia, 10 patients with essential and 9 with transient hypertension during pregnancy, were investigated regarding circulating immune complexes by a Clq-binding assay and a PEG precipitation assay. The women were studied during pregnancy, 2 and 5 days after childbirth, and also 3 and 6 months afterwards. The frequency of circulating immune complexes was not significantly increased in any of the groups when compared with that in 18 normotensive pregnant control subjects and 19 non-pregnant controls. Thus Clq-binding and PEG-precipitable immune complexes are a feature neither of normal pregnancy, nor of pregnancy complicated by hypertension or pre-eclampsia.
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PMID:Circulating immune complexes and hypertension in pregnancy. 644 Apr 5

1 Because they affect isolated cerebral arteries, some calcium antagonists have been studied on the intact cerebral circulation of the rat.2 Global cerebral blood flow ((133)Xe clearance technique) was measured in anaesthetized rats. Neither perhexiline (0.1 mug/kg to 1.0 mg/kg, i.v.) nor diltiazem (0.06-0.6 mg/kg, i.v.) had any significant effect on resting cerebral blood flow when measured 5 min after each dose. A high dose of nifedipine (1.0 mg/kg, i.v.) was administered during induced hypocapnia. Nifedipine failed to modify the hypocapnic vasoconstriction of the cerebral vasculature when compared to vehicle-treated rats.3 The possibility of discrete changes in regional cerebral blood flow was investigated. Local cerebral blood flow was measured in a number of brain regions by the [(14)C]-ethanol technique 15 min after the administration of nifedipine (20 or 100 mug/kg, i.v.). Nifedipine had no apparent effect on regional blood flow in the rat brain.4 Acute arterial hypertension increases protein leakage into the brain, a phenomenon susceptible to drugs that act on endothelial pinocytosis which is known to be calcium-dependent. The increase in protein extravasation, induced by the intravenous administration of either angiotensin II or adrenaline, was unchanged in rats previously treated with either nimodipine (20 mug/kg, i.v.) or nifedipine (50 mug/kg, i.v.) when dissolved in ethanol alone. However, nifedipine (20 mug/kg, i.v.) when dissolved in a solution of polyethylene glycol and ethanol further enhanced the hypertension-induced increase in brain albumin permeability.5 In conclusion, we have been unable to demonstrate any apparent effects of various calcium antagonists on the intact cerebral circulation of the rat, despite the number of different experimental models used.
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PMID:Calcium antagonists: effects on cerebral blood flow and blood-brain barrier permeability in the rat. 687 38

The effect of naloxone upon water consumption by rats was assessed using two intensities each of IV NaCl (Hyperosmolarity), SC polyethylene glycol (hypovolemia), and IV angiotensin II. In each case naloxone produced a dose-related reduction in the amount drunk. Angiotensin-induced drinking was most easily inhibited, and was abolished by only 1 mg/kg naloxone. In contrast, 1 mg/kg naloxone produced only a 50% reduction NaCl-induced drinking, and hypovolemia-induced drinking was not completely reversed by 5 mg/kg. Naloxone was without effect upon the natriuresis after NaCl, or the hypertension during AII administrations. Parallels are drawn between the effects of naloxone on these types of thirst, and of other perturbations including brain damage and taste adulteration.
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PMID:Comparison of the suppression by naloxone of water intake induced in rats by hyperosmolarity, hypovolemia, and angiotensin. 705 17

In a 30 years period, 42 children were admitted for optic nerve and chiasm gliomas; 20 patients aged less than 5 years and 22 between 6 and 16 years. Duration of symptoms ranged from 13.15 months in children aged less than 5 years, to 10.18 months in patients aged more than 6. Onset of symptoms were characterized by visual impairment and/or proptosis in 73.8%, diencephalic disorders in 16.6% and intracranial hypertension in 9.5%. All patients underwent skull X-rays; 31 had a PEG taken and 12 a CT scan. Surgery was prompted in 27 patients, 2 of which died in postoperative course. Radiotherapy was the treatment of choice in the other 15 patients, 40 patients were followed up: the best results were obtained in the group of patients operated on and irradiated.
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PMID:Optic nerve and chiasm gliomas in children. 714 83

Estimation and measurement of serum osmolality can be of value in the clinical management of certain forms of critical illness. Osmolality is a measure of the concentration of osmotically active particles, or solutes, in a solution. Only low-formula weight ions and uncharged molecules that are present in relatively high concentrations contribute significantly to serum osmolality. Serum osmolality can be easily estimated from the three major osmotic constituents of normal serum (sodium, urea, and glucose) by a simple formula. An understanding of serum osmolality, its laboratory measurement, its bedside estimation, and the concept of the osmole gap, is crucial in making a preliminary diagnosis of methanol and ethylene glycol intoxication, as well as a few other related compounds. There are important caveats to this use of the osmole gap, because under certain circumstances both false-positive and false-negative interpretations may occur. The osmole gap may also be helpful for confirming pseudohyponatremia, as a gauge for dosing mannitol and glycerol when used to treat intracranial hypertension, and as a prognostic indicator in circulatory shock.
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PMID:The serum osmole gap. 798 82


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