Israel Medical Association Journal

Background: Hyperhomocysteinemia is a well-recognized risk factor for accelerated atherosclerosis in hemodialysis patients.

Objectives: To examine the effects of two doses of vitamins B6 and B12 and folic acid on homocysteine levels in hemodialysis patients and assess the functional impact of the methylenetetrahydrofolate reductase genotype on the response to treatment.

Methods: In a randomized prospective study, we assessed the effects of folic acid and two doses of B-vitamins in 50 hemodialysis patients with hyperhomocysteinemia. Patients were divided into two groups: 26 patients (group A) who received 25 mg of vitamin B₆ daily and one monthly injection of 200 µg vitamin B12, and 24 patients (group B) who received 100 mg of vitamin B6 daily and one monthly injection of 1,000 µg vitamin B12. In addition, both groups received 15 mg folic acid daily. Patients were evaluated for homocysteine levels as well as for coagulation and a thorough lipid profile. Baseline Hcy[1] levels were determined after at least 4 weeks washout from all folic acid and B-vitamins that were given. MFTHR[2] alleles were analyzed, as were activated protein C resistance, von Willebrand factor and lupus anticoagulant.

Results: Basal plasma Hcy levels were significantly elevated in hemodialysis patients compared with normal subjects (33.8 ± 4.3 vs. 4.5 to 14.0 mmol/L). Following treatment, Hcy levels were significantly reduced to 21.2 ± 1.6 in group A and 18.6 ± 1.4 mmol/L in group B (P < 0.01). There was no difference in Hcy reduction following the administration of either high or low dosage of vitamins B6 and B12 utilized in the present study. There was no correlation between Hcy levels or thrombophilia and high incidence of thrombotic episodes in hemodialysis patients. Genotypic evaluation of MTHFR revealed that the presence of homozygous thermolabile MTHFR (n = 5) was associated with higher Hcy levels and better response to treatment (Hcy levels decreased by 58%, from 46.2 ± 14.6 to 19.48 ± 4.1 mmol/L following treatment). In patients with heterozygous thermolabile MTHFR (n = 25), Hcy levels decreased by 34%, from 31.2 ± 3.7 to 18.1 ± 1.1 mmol/L following treatment. The efficacy of high and low doses of B-vitamins on the reduction of homocysteine levels was comparable.

Conclusions: Treatment with B-vitamins in combination with folic acid significantly decreased homocysteine levels in hemodialysis patients, independently of the tested doses. In addition, mutations in MTHFR were associated with elevated plasma levels of Hcy. Neither vascular access nor.

Background: A high total plasma homocysteine level is an independent risk factor for cardiovascular and cerebrovascular disease, but the evidence connecting plasma tHcy level with hypertension is inconsistent.

Objective: To determine the association between plasma tHcy level and some common risk factors for cerebrovascular disease (recurrent  stroke, diabetes mellitus, hypertension, ischemic heart disease and hyperlipidemia) in patients presenting with primary or recurrent acute ischemic strokes.

Methods: This retrospective cross-sectional chart analysis was conducted in a university-affiliated referral hospital. During an 18 month period we identified 113 acute ischemic stroke patients (mean age 71.2), 25 of whom had a recurrent stroke. Plasma tHcy[1] level, obtained 2–10 days after stroke onset, was determined by the high performance liquid chromatography method with fluorescence detection. A multivariate logistic regression model was used to determine the independent relationship between each potential risk factor and tHcy level above or below the 75th percentile.

Results:  Hypertension was more frequent among patients with plasma tHcy level above than below the 75th percentile (51.7% vs. 80.8%, respectively, P = 0.012). After adjusting for demographic and clinical variables, the odds ratio for recurrent stroke and hypertension, with tHcy above or below the 75th percentile, was 3.4 (95% confidence interval 1.01–10.4, P = 0.037) and 4.02 (95% CI[2] 1.2–13.9, P = 0.028), respectively.

Conclusions: A high plasma tHcy level is associated with history of hypertension and recurrent stroke among patients presenting with acute ischemic stroke. These results were independent of other risk factors such as atrial fibrillation, diabetes and hyperlipidemia. Hypertensive stroke patients with hyperhomocysteinemia should be identified as high risk patients as compared to non-hypertensive stroke patients, and may warrant more vigorous measures for secondary prevention.

Patients with diabetes and/or insulin resistance syndrome are at increased risk for developing cardiovascular disease. The UKPDS raised a great debate about the relative importance of hyperglycemia in the development of cardiovascular disease. Recently, several epidemiologic studies have suggested that high postprandial blood glucose levels are associated with a significant risk for the development of cardiovascular disease as well as a grave prognosis for these patients during acute coronary events. In addition, a number of reports reinforce the thesis that postprandial hyperglycemia is a risk factor for mortality. Our review summarizes the current knowledge on the relation between blood glucose, insulin levels, and cardiovascular morbidity and mortality, relating these data to the new World Health Organization and American Diabetes Association classification of disturbed glucose metabolism.

Background: Acarbose has become an important adjuvant therapy for diabetic patients. Many of these patients are also treated with digoxin for congestive heart failure or chronic atrial fibrillation

Objective: To evaluate a possible drug interaction between acarbose and digoxin.

Methods: An open-label, analyst-blind, randomized, crossover, two-period study was conducted in 11 healthy subjects. In period I, each subject received one single oral dose of 0.75 mg digoxin. In period ll, they were given acarbose tablets., 60 mg-3 times a day for 12 days. On day 8, one hour after acarbose administration, a single oral dose of 0.75 mg digoxin was administered. The study periods were separated by a 3 week washout interval: Serum. digoxin levels., over. time, in the two periods were compared by standard techniques;

Results: There were no differences in the pharmacokinetic parameters of digoxin in the two periods, apart from a significant increase in the mean maximum serum concentration (Cmax) when digoxin was given with acarbose (5.97 compared to 4.67 g/L, P = 0.02). Simulated steady-state peak levels of digoxin (Cmax,ss) achieved with a daily dose of 0.25 mg digoxin, in the presence.and absence of acarbose, were 2.89 and 2.40 g/L respectively (P =0.05); Simulated steady-state trough (Cmin,ss) and average (Cave,ss) concentrations were similar and within the therapeutic window.

Conclusion: There was no significant pharmacokinetic interaction between digoxin and acarbose at current therapeutic doses in the healthy volunteers. This interaction should be further studied with higher doses of acarbose and at steady-state conditions.
 

Background: Previous studies have shown a low prevalence of diabetes and other cardiovascular risk factors among Bedouins living in the Negev Desert. New evidence suggests that diabetes is becoming highly prevalent.

Objectives: To estimate the prevalence of diabetes in the town of Rahat, describe the cardiovascular risk factor profile and therapeutic modalities for diabetes and related conditions in this population, and compare these findings with those in the Jewish population.

Methods: A complete record review of all known diabetic individuals aged 35 and older registered at the Rahat Clinic (Clalit Health Services) was carried out by a trained nurse and a research assistant. Information on demographic, anthropometric and clinical characteristics was abstracted. Data on prescribed hypoglycemic agents and other medications were also obtained.

Results: Of the 316 known diabetic patients in the clinic, complete data were available for 271 (85.8 %). The prevalence of known diabetes was 7.3% in males and 9.9% in females. Females had a significantly higher body mass index than males (30.9 vs. 29, P < 0.002), but lower levels of HBA1c and microalbuminuria. Oral hypoglycemic medications were taken by 69% of women and 76% of men, and insulin by 19% of women and 15% of men.

Conclusions: Compared with data on Jewish diabetic patients in the Negev and Israel, the overall prevalence of diabetes in the population of Rahat is higher, but their cardiovascular risk profile is better, except for obesity. These findings support the hypothesis that diabetes and obesity have become major public health problems among Bedouins.
 

This review summarizes the clinical, metabolic and genetic characteristics of early-onset type 2 diabetes in Mexico. Early-onset type 2 diabetes is both a clinical challenge and a public health problem. It is calculated that almost 300,000 Mexican diabetics are diagnosed between the ages of 20 and 40. The large Mexican family structure and the high prevalence of the disease provide a unique opportunity to identify the genes and the metabolic abnormalities involved in this form of the disease. In a hospital-based population, our group found that insulin deficiency was the main defect in this form of diabetes. Mutations in the HNF-1α or HNF-4α genes or autoimmunity to the beta cell were found in a small proportion of cases, leaving unexplained the majority of cases. Also discussed are the epidemiologic and therapeutic implications of early-onset type 2 diabetes, and the possible role of genetic testing for prevention.