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

A 52-year-old apparently healthy, normotensive woman who presented for elective cholecystectomy experienced intra-operative hypertension and tachycardia, which were controlled by propranolol. Oesophageal temperature increased, there was a metabolic and respiratory acidosis with hypoxaemia, and malignant hyperthermia was diagnosed. Severe cardiogenic pulmonary oedema ensued, and was treated with intravenous glyceryl trinitrate. Ventricular fibrillation caused cardiac arrest, and this was treated successfully. Postoperatively a phaeochromocytoma was discovered, and removed at a subsequent operation. The case illustrates the similarities in presentation of malignant hyperthermia and phaeochromocytoma, and the possibility that misdiagnosis may exacerbate the crisis.
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PMID:Phaeochromocytoma--a presentation mimicking malignant hyperthermia. 323 80

The differences observed among rat strains in both basal [Na+]i and the several cation transport systems seem to be due to the different genetic background as clearly shown in F2 populations or after bone marrow transplantation in MHS. The same may be true for humans. In spite of all the caution taken in interpreting the data, because of the great possibility of methodological errors, it is likely that the differences observed in many laboratories are due to uneven genetic or ethnic composition of the samples studied, as shown by Dagher and Canessa. One intriguing observation is that most reports of "low Na-K cotransport" values in hypertensive patients are from Mediterranean countries (Italy, France, and Spain), whereas most reports of "high," or "not low Na-K cotransport," or very high values of countertransport came from populations originating from North Europe (Denmark, USA, South African whites). We are not aware of any study on erythrocyte Na-K cotransport performed in Great Britain (the greatest source of American immigrants). Indeed the difference in cotransport values between North and South European hypertensives might be due to different environmental factors, but if this is so, the difference does not depend on the salt consumption or plasma lipids that are similar in our high and low Na-K cotransport hypertensives (Cusi D et al, submitted). The picture seems relatively less confusing for calcium. The most consistent alterations in different models of hypertension is a decreased Ca-pump in SHR, MHS, and DOCA rats, reduced calcium binding in SHR and MHS, and reduced microsomal ATP dependent calcium uptake in SHR and DOCA rats. [Ca++]i, which is increased in established hypertension in man and rats, is normal in young prehypertensive rats and humans, and returns to normal values after pharmacological treatment of hypertension. This pattern of changes suggests that genetic control of these transport systems is weaker, and probably much influenced by different environmental conditions. However, because of the pivotal role of calcium in vascular smooth muscle cell concentration, its intracellular increase may be the common pathway of the different forms of hypertension. What remains unclear is the relation, if any, between calcium and sodium. Blaustein tried to find a link between them, but his hypotheses have yet to be confirmed.
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PMID:Role of cellular sodium and calcium metabolism in the pathogenesis of essential hypertension. 329 35

Erythrocyte membrane 22Na and 45Ca transport, osmotic stability and antigenic composition were investigated in 3 strains of rats with spontaneous hereditary hypertension (SHR, SHR SP, MHS), as well as normotensive controls for SHR and SHR SP (WKY) and for MHS (MHS). All strains of spontaneously hypertensive rats showed increased passive membrane permeability for sodium, that was due to increased operation rate of the Na+, K+-cotransport system. Metabolizing sodium is increased in the erythrocytes of Japanese rats (SHR and SHR SP), and decreased in Milan rats (MHS), as compared to normotensive controls. After four hours of incubation with orthovanadate, erythrocyte 45Ca levels were 2-3 times as high in SHR and SHR SP as they were in WKY. In the presence of valinomycin, erythrocyte resistance to hypoosmotic hemolysis was essentially higher in SHR and SHR SP than it was in WKY. These differences are related to a changed rate of anion transport through the band 3 protein. There were no differences in this respect between MHS and MNS. An antigen with a molecular weight of 37-39 kD was detected in erythrocyte membranes of WKY and could not be detected in erythrocytes of other rat groups, including the MNS. It is suggested that different molecular origins of membrane disorders may be an immediate cause of different mechanisms of arterial hypertension in Japanese and Milan animals.
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PMID:[Characteristics of the structural-functional status of erythrocyte membranes in 3 strains of rats with spontaneous genetic hypertension]. 335 98

Many similarities in kidney-function abnormalities were found between hypertensive rats of the Milan strain (MHS) and young normotensive human subjects with hypertensive parents, compared with the appropriate controls. These similarities included an increased glomerular filtration rate, increased pressor effect of the kidney after transplantation, increased 24-h urinary output and lower plasma renin activity and urinary kallikrein. The isolated MHS kidney perfused in vitro with an artificial medium had a higher glomerular filtration rate, a higher urinary output, higher tubular sodium reabsorption and higher oxygen consumption than the kidney of control Milan normotensive rats (MNS). Further, reogenic sodium transport across brush border vesicles isolated from proximal tubular cells is faster in MHS than in MNS. Erythrocytes and proximal tubular cells of MHS have a lower volume and sodium content than those of MNS, while sodium transport is faster and the Ca2+-ATPase at Vmax is lower. This indicates that the 'genetic' cellular abnormality responsible for the renal-function abnormality and the hypertension is also present in erythrocytes. Thus these cells may be used to study the genetic cellular mechanisms of hypertension. Experiments with bone marrow transplantation and with F2 hybrids obtained by crossing the F1 (MHS X MNS) hybrids showed that the MHS erythrocyte abnormalities are genetically determined within the stem cells and are genetically associated with the hypertension. Since, in human hypertensives, there was a correlation between abnormal erythrocyte sodium transport and renal function, it is proposed that erythrocytes may be used in studying the cellular molecular mechanisms of hypertension.
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PMID:A renal abnormality in the Milan hypertensive strain of rats and in humans predisposed to essential hypertension. 353 35

Studies of whole-kidney function and micropuncture measurements in superficial nephrons were performed to investigate the role of the tubuloglomerular feedback (TGF) in the excretion of salt and water in hydropenic and volume-expanded rats of the spontaneously hypertensive Milan strain (MHS). The rats were 3.5-5 and 5-7 wk old, and age-matched animals from the Milan normotensive strain (MNS) served as controls. There was no difference in mean arterial blood pressure (Pa) between the 3.5- to 5-wk-old prehypertensive MHS (MHSp) and MNS rats, but the glomerular filtration rate (GFR) was higher in MHSp than in MNS [1.35 vs. 0.80 ml X min-1 X g kidney wt (KW)-1, P less than 0.01]. The distal single-nephron glomerular filtration rate (SNGFR) was also higher in MHSp than in MNS (28.6 vs. 20.2 nl X min-1 X g KW-1, P less than 0.05). TGF was determined from both stop-flow pressure response and proximal and distal SNGFR. It was found that MHSp exhibited essentially no TGF response. During development of hypertension 5- to 7-wk-old MHS (MHSd) had a higher Pa than MNS (120 vs. 98 mmHg, P less than 0.01). Normally GFR and SNGFR increase with age, and such was the case with MNS (0.8 to 1.02 ml X min-1 X g KW-1 and 20.2 to 23.4 nl X min-1 X g KW-1), but in MHSd there was a decrease in both GFR and SNGFR with age (1.35 to 1.10 ml X min-1 X g KW-1 and 28.3 to 18.3 nl X min-1 X g KW-1).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Increased tubuloglomerular feedback activity in Milan hypertensive rats. 371 52

This article deals with consultation between anesthesiologists and urologic surgeons. Some of the subjects discussed represent problems that occur commonly, such as cardiac arrhythmias and intraoperative hypertension. Other subjects, though representing less common problems, have much more serious consequences and thus should be brought to the attention of surgeons. This latter group includes malignant hyperthermia, hyponatremia during transurethral prostatic resection, and cardiac arrest.
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PMID:Intraoperative anesthetic consultation. 402 90

Syndrome malin refers to neuroleptic malignant syndrome (NMS), a combination of extrapyramidal symptoms, hyperthermia, autonomic dysfunction, hypertension, and coma, which has been reported primarily with haloperidol administration, but also with fluphenazine, thiothixene, and thioridazine. NMS is much more severe than typical extrapyramidal reactions to neuroleptic agents and can result in fatality. The syndrome is not dose related and can begin within hours of initiation of therapy or after months of treatment. Treatment of NMS has been mainly supportive in the past. Recent reports have suggested benefits from the use of bromocriptine and amantadine (dopaminergic agonists), based on a possible etiology of neuroleptic-induced dopaminergic blockade. Dantrolene also has been utilized successfully in NMS on the hypothesis that the syndrome is similar to anesthetic-induced malignant hyperthermia. These agents provide a more specific treatment for this potentially lethal syndrome.
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PMID:Therapy of syndrome malin. 613 52

Electron microprobe analysis was used to determine cellular concentrations of potassium and sodium in renal cortical cells of hypertensive rats of the Milan strain (MHS) and spontaneously hypertensive rats of the stroke prone strain (SHRSP) and their respective controls. Potassium concentrations in proximal and distal tubular cells were similar in both strains of hypertensive rats compared with their normotensive controls. In MHS rats proximal tubular cell sodium concentration was lower than in controls by 3.1 mmol/kg ww, whereas in both proximal and distal tubular cells of SHRSP sodium concentrations were higher than in controls by 5.3 and 4.3 mmol/kg ww, respectively. These results indicate that changes in the transport characteristics of the renal tubular epithelium are a feature of both models of hypertension.
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PMID:Sodium and potassium concentrations of renal cortical cells two animal models of primary arterial hypertension. 659 94

Serial ECG's were reviewed in 93 consecutive patients who were proven to be susceptible to malignant hyperthermia by caffeine contracture and ATP depletion tests on skeletal muscle biopsies, but who were without a history of pyrexic crises. There were 46 males and 47 females with a mean age of 33 years. Abnormal ECG's were found in 26 of the patients, with conduction defects in 14, repolarization abnormalities (non-specific ST-T changes) or "Q" waves in nine and increased voltages suggesting left ventricular hypertrophy in three (in the absence of hypertension). An abnormal ECG in a young patient may reflect malignant hyperthermia susceptibility.
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PMID:Electrocardiographic abnormalities associated with malignant hyperthermia susceptibility. 706 30

1. Blood pressure was measured and plasma levels of noradrenaline and adrenaline were determined radioenzymatically under basal conditions and after 10% blood volume reduction in blood drawn through catheters previously implanted in young and adult rats of two different genetically hypertensive strains: the Kyoto strain (SHR) and the Milan strain (MHS), and in their respective controls: Wistar--Kyoto strain (WKY) and Milan normotensive strain (MNS). 2. Under basal conditions no differences were observed between plasma noradrenaline and adrenaline levels in SHR and MHS rats and in the controls, at any age. Haemorrhage produced a greater fall in the blood pressure (P less than 0.01) of young and adult hypertensive strains (SHR-MHS) than in WKY and MNS rats, and a greater rise in plasma adrenaline (P less than 0.01). 3. These results suggest that: (a) there may be differences in involvement of the sympathetic nervous system in the pathogenesis of hypertension in SHR and MHS rats but not such as to cause differences in plasma catecholamine levels in either young or adult rats; (b) haemorrhage activates the sympatho--adrenal systems more in SHR and MHS rats, than in controls, and the greater percentage fall in blood pressure is probably due to a difference in reflex venoconstriction.
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PMID:Plasma concentrations of catecholamines in two strains of spontaneously hypertensive rats at different ages. 731 24


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