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

We describe a female infant with typical features of the cobalamin C form of combined methylmalonic aciduria and homocystinuria who also had the hemolytic-uremic syndrome with thrombocytopenia, microangiopathic hemolytic anemia, hypertension, and renal failure. Review of this and other described cases of the cobalamin C defect suggests that the hemolytic-uremic syndrome is part of the phenotypic spectrum of this inborn error of cobalamin metabolism.
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PMID:Cobalamin C defect associated with hemolytic-uremic syndrome. 159 55

Two cases in the same sibship are reported. The elder patient, who had posterior dislocation of the lens resulting in glaucoma and significant psychomotor retardation, died at the age of 13 with malignant arterial hypertension. Death was caused by thrombotic events (left carotid artery, coronary vessels, renal arteries and arterioles with fibrous endarteritis). The sister, aged 10, had psychomotor retardation and anomalies of both lenses. Chromatographic studies of serum and urine amino acids confirmed the diagnosis of homocystinuria. The form was pyridoxine-sensitive as shown by the results of therapy with pyridoxine and folates. We suggest that homocystinuria, although infrequent, should be routinely looked for in every child with a thrombotic event since a pyridoxine-folate combination is successful in half the cases, preventing the development of complications especially when initiated early.
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PMID:[2 familial cases of homocystinuria one of which revealed by fatal hypertensive encephalopathy]. 235 Jan 47

Homocystinuria, an inherited disorder associated with premature atherosclerosis, represents a severe form of methionine intolerance. To analyze the importance of milder forms of methionine intolerance in the genesis of vascular disease, the relation between provokable methionine intolerance and coronary artery disease was investigated. In a group of 138 men, aged 31 to 65 years (mean 53), referred for cardiac catheterization, plasma homocystine was measured before and 6 hours after an oral l-methionine load (0.1 g/kg). Thirty-nine subjects found to have normal coronary arteries had a mean post-load plasma homocystine level of 0.59 +/- 0.37 mumol/liter. A criterion at the 95th percentile (1.64 SD above the mean) was selected and applied to the remaining 99 subjects with coronary artery disease (0.70 +/- 0.68 mumol/liter). Sixteen (16%) of 99 subjects with coronary artery disease exceeded this level as compared with 1 (2%) of 39 subjects without coronary artery disease (p less than 0.04). The risk of coronary artery disease in men with provokable methionine intolerance was increased sevenfold as estimated by the odds ratio. By correlation matrix and multivariate regression analyses, provokable homocystinemia was predictive of coronary artery disease and was independent of tobacco smoking, hypertension, diabetes mellitus, serum cholesterol and age. It is proposed that men with mild methionine intolerance exposed to the high methionine content of the Western diet may develop intermittent homocystinemia and thus may be at greater risk for the development of coronary artery disease.
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PMID:Methionine intolerance: a possible risk factor for coronary artery disease. 403 Dec 85

Premature arteriosclerosis and thromboembolic events are well-known complications of homozygous homocystinuria due to cystathionine synthase deficiency. It is unknown whether heterozygosity for homocystinuria predisposes to premature vascular disease. We explored the frequency of excessive homocysteine accumulation after standardized methionine loading in 75 patients presenting with clinical signs of ischemic disease before the age of 50:25 with occlusive peripheral arterial disease, 25 with occlusive cerebrovascular disease, and 25 with myocardial infarction. In seven patients in each of the first two groups but in none of the patients in the third group, heterozygosity for homocystinuria was established on the basis of pathological homocysteinemia after methionine loading and cystathionine synthase deficiency in skin fibroblast cultures. Because the frequency of heterozygosity for homocystinuria in the normal population is 1 in 70 at the most, we conclude that this condition predisposes to the development of premature occlusive arterial disease, causing intermittent claudication, renovascular hypertension, and ischemic cerebrovascular disease.
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PMID:Heterozygosity for homocystinuria in premature peripheral and cerebral occlusive arterial disease. 188 23

A boy with homocystinuria diagnosed at the age of fourteen during arterial hypertension diagnostic procedures performed because of severe arterial hypertension. Hypertension was caused by thromboembolic changes within segmental branch of renal artery.
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PMID:[Arterial hypertension as a complication of homocystinuria in a 14-year old boy]. 760 2

Homocyst(e)ine [H(e)], the sum of homocysteine, homocystine, and the homocysteine-cysteine mixed disulfide, free and protein-bound, has been shown to be associated in retrospective case control studies, and in one prospective study, with vascular disease, including coronary artery disease (CAD), cerebrovascular disease, and peripheral vascular disease. Elevated levels of homocyst(e)ine severe enough to cause homocystinuria are seen in severe nutritional deficiencies of vitamin B12, folic acid and vitamin B6. Rare genetic disorders of vitamin B12 synthesis of 5'-10'-methylene tetrahydrofolate reductase, or the pyridoxal phosphate-dependent enzyme cystathionine beta-synthase may cause severe hyperhomocyst(e)inemia and homocystinuria. The clinical manifestation of these disorders are mental retardation, neurological disorders, and widespread thromboembolic phenomena. The measurement of H(e) is currently performed using high-pressure liquid chromatography with fluorescence detection. Other methods, especially mass spectroscopy, are also used. Internal standards using increasing concentrations of homocystine and acetylcysteine and several external standards are used to ensure accuracy of the assay. Milder elevations of H(e) have recently been associated with vascular disease, in both men and women. The strength of this association appears to be stronger for peripheral and cerebrovascular disease than for CAD. Nevertheless, several case control studies in Europe, Canada, and the United States have shown that H(e) levels are elevated in CAD patients compared with controls, and H(e) levels are independent of the conventional cardiovascular risk factors (age, gender, lipid and lipoprotein cholesterol levels, hypertension, or cigarette smoking). One prospective study, the Physicians' Health Study, has shown that H(e) levels are slightly but significantly higher in CAD cases vs controls in a population of US physicians.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Measurement of homocyst(e)ine in the prediction of arteriosclerosis. 762 74

Cerebral infarction before the age of 45 years accounts for 4-6% of all strokes. The etiology remains unexplained in a significant proportion of patients even after extensive investigations. The reported risk factors of this age group are cardiopathies, hypertension, smoking, hypercholesterolemia, reduction of anticoagulant proteins, hypercoagulable states, antiphospholipid antibodies primary syndrome, antiphospholipid antibodies secondary syndrome, some hemoglobinopathies, hyperviscosity syndromes, vasculitis, collagen vascular diseases, fibromuscular dysplasia, arterial dissections, migraine, myopathy encephalopathy lactic acidosis stroke like episodes, homocystinuria, familial amyloid angiopathy, microangiopathy with retinopathy encephalopathy and deafness, systemic lupus erythematosus, use of cocaine, traumas or manipulations of neck, AIDS. From 1/1/94 to 04/30/95 we observed 19 patients with cerebral infarctions and 9 patients with transitory ischemic attacks in young people. The aim of our study was to apply a diagnostic protocol by sequential tests of first level and second level. According to this protocol we found that the more common risk factors were ischemic cardiopathy, hypertension, smoking and hypercholesterolemia. Moreover we observed other independent risk factors, although less frequent, like the antiphospholipid antibodies, neurolupus, AIDS, deficit of protein S.
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PMID:[The application of a new diagnostic protocol for stroke in the young]. 876 46

In homozygous homocystinuria due to cystathionine synthase deficiency, characterized by severe hyperhomocysteinemia, there is a high incidence of vascular complications. These observations focus on homocysteine as an atherogenic and thrombophilic agent. At the present time, there is also convincing evidence that even mild hyperhomocysteinemia is a risk factor for cardiovascular disease due to occlusive arterial complications. Furthermore, a positive association between mild hyperhomocysteinemia and the occurrence of venous thrombosis has been shown but needs further study. Mildly elevated homocysteine levels affect the arterial system independently from conventional risk factors. This newly- recognized factor seems equally strong in risk to hypercholesterolemia and smoking, while hypertension leads to a larger excess risk. It interacts synergistically with hypertension and smoking in a joint arteriosclerotic effect in patients with the concomitant presence of these risk factors. The homocysteine-lowering efficacy of a simple and safe vitamin regimen has been proven but data on the clinical outcome of such intervention are lacking thus far.
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PMID:Hyperhomocysteinemia as a risk factor for arterial and venous disease. A review of evidence and relevance. 919 7

The possibility that modest elevations in the level of blood homocysteine (hyperhomocysteinaemia) could contribute to cardiovascular disease arose from investigation of patients with rare, severe homocysteine elevations caused by cystathionine beta-synthase deficiency. Such patients often had thromboembolic events before the age of 30 years. Since the established cardiovascular risk factors could only partly account for the occurrence and severity of vascular disease in the general population, other risk factors had to exist, and homocysteine elevation seemed to be a possible candidate. Australian case-control studies identified an association between mild homocysteine elevation and early-onset coronary disease, and also with chronic renal failure. Patients in the latter group have a high prevalence of unexplained vascular disease and particularly high homocysteine levels. Such elevations in levels of homocysteine in vascular patients could usually be normalised by daily supplementation with folic acid (1-5 mg) while in patients with chronic renal failure 5 mg of folic acid daily markedly reduced the increased concentrations of homocysteine. These initial observations have been confirmed by many investigators and biologically plausible mechanisms for homocysteine-induced vascular dysfunction, and particularly endothelial dysfunction, have been identified. However, associations between hyperhomocysteinaemia and other risk factors, such as smoking and hypertension, have also been documented and need to be controlled for when assessing any increase in risk that homocysteine may independently confer. Although it has been established that lowering the greatly elevated blood homocysteine levels in homocystinuria, due to cystathione beta-synthase deficiency, unquestionably reduces cardiovascular risk, it remains to be determined whether normalising mild homocysteine elevation could reduce cardiovascular risk. Trials to test this possibility have been initiated and others are planned.
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PMID:Novel risk factors for vascular disease: the homocysteine hypothesis of cardiovascular disease. 991 68

The proposal that antioxidants may retard the progression of atherosclerosis is not new. Published studies examining the effect of antioxidants on experimental antioxidants extend back to 1940. The results have all been inconsistent. However, the data regarding the beneficial effects of retarding atherosclerotic progression are strong enough to warrant continued research on the lipoprotein oxidation theory or atherosclerosis. However, caution is needed to avoid embracing a concept without proof. It should be noted that the National Cholesterol Education Program does not recommend the use of antioxidant vitamin supplements to reduce CAD. Atherogenesis is produced by multiple factors. To believe that all such factors are mediated by uncontrolled oxidative events is, to say the least, naive. Finally, should antioxidants prove to be effective in retarding coronary atherosclerosis, their place on the therapeutic ladder of CAD prevention would be low. The overwhelmingly proven evidence favors the following factors that have been proven to lower morbidity and mortality due to atherosclerosis: (a) treatment of hypertension, (b) cessation of tobacco use, (c) treatment of dyslipidemia, (d) achieving a normal weight, (e) regular exercise, (f) treatment of homocystinuria, especially in cases with renal disease, and (g) antioxidants.
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PMID:The use of antioxidants in retarding atherosclerosis: fact or fiction? 1007 4


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