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Biomedical subjects

M Bursztyn

Publications and source records attributed to M Bursztyn.

At least 55 records · Page 3Linked to original sources
PubMed1995

Experimental colitis is ameliorated by inhibition of nitric oxide synthase activity.

Enhanced nitric oxide (NO) generation by stimulated NO synthase (NOS) activity may, through its oxidative metabolism contribute to tissue injury in experimental colitis. In this study the possible amelioration of experimental colitis by NG-nitro-L-arginine methyl ester (L-NAME), an inhibitor of NOS activity, was evaluated. Colitis was induced in rats by intracolonic administration of 30 mg trinitrobenzene sulphonic acid (TNB) dissolved in 0.25 ml 50% ethanol or by flushing the colon of capsaicin pretreated rats with 2 ml of 5% acetic acid. In several experiments, L-NAME 0.1 mg/ml was added to the drinking water at the time of colitis induction with TNB or seven days before acetic acid treatment. Rats were killed at various time intervals after induction of colitis. A 10 cm distal colonic segment was isolated, weighed, lesion area measured, and explants organ cultured for 24 hours for determination of NO generation by the Greiss reaction. The rest of the mucosa was scraped for determination of myeloperoxidase and NOS activities and leukotriene generation. In TNB treated rats mean arterial pressure was also determined up to 72 hours after damage induction, with or without cotreatment with nitroprusside. L-NAME significantly decreased the extent of tissue injury in TNB treated rats. Seven days after TNB treatment lesion area was reduced by 55%, colonic weight by 37%, and myeloperoxidase and NOS activity by 59% and 42%, respectively. Acetic acid induced colitis in capsaicin pretreated rats was also significantly decreased by L-NAME. Twenty four hours after acetic acid treatment lesion area was reduced by 61%, colonic weight by 21% and NOS activity by 39%. Mean (SEM) arterial blood pressure in TNB+L-NAME treated rats was 37.6 (8.1) mm Hg higher than in TNB treated rats, an effect that was only partially abolished by nitroprusside. These results show that inhibition of NO synthesis by an L-arginine analogue significantly ameliorates the extent of tissue injury in two models of experimental colitis, an effect that is not due only to its vasoconstrictor properties. Modulation of NO generation may be a novel therapeutic approach in inflammatory bowel disease.

Animals↗
PubMed1995

Blood pressure and insulin in Ethiopian immigrants: longitudinal study.

Immigration from Ethiopia to Israel exposed subjects from an underdeveloped environment to that of a westernised, developed country. In previous cross-sectional analyses we found that residence in Israel for more than 2 years was associated with a rise in blood pressure which, in turn, was associated with a rise in lipids and insulin levels. Herein we report longitudinal follow-up and baseline examination of 53 young male Ethiopians who resided in a relatively controlled environment (agricultural boarding schools) for 2 years after immigration. Their mean age, when re-examined, was 23 +/- 3 years. Body mass index (20 +/- 2 kg/m2) and triceps' skinfold (71 +/- 32 mm) were not different from baseline values. However, over the 2 years blood pressure rose from 118 +/- 9/62 +/- 11 to 129 +/- 13/71 +/- 10 mmHg, P < 0.0001 for both systolic and diastolic pressures. At 2 years 11 of 53 subjects (20.7%) had hypertension. Total high-density lipoprotein cholesterol and triglyceride levels increased from 131 +/- 27, 36 +/- 8 and 65 +/- 22 mg/dl to 146 +/- 29, 43 +/- 10 and 98 +/- 42 mg/dl, respectively; P < 0.00001 for all. Surprisingly, glucose tolerance (to oral 75 g load) improved and the sum of insulin (first and second hour post-load) decreased significantly and was not correlated with blood pressure changes. Only systolic blood pressure was an independent predictor of incident hypertension (r2 = 0.33, P < 0.0001) in multiple regression analysis.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Prediction of hypertension by the insulinogenic index in young Ethiopian immigrants.

OBJECTIVE: Hyperinsulinaemia may be associated with hypertension, hyperlipidaemia and glucose intolerance. In the present study we compared the consequence of immigration from Ethiopia to Israel in order to elucidate environmental effects on these variables. DESIGN: A cross-sectional analysis of 337 young, male Ethiopian immigrants who were placed in boarding schools were divided into two groups: group I was in Israel for < 3 months (n = 180) and group II was in Israel for > 2 years (n = 157). Both groups were attending the same schools and were fed from the same kitchens. METHODS: Sitting blood pressure, body mass index, triceps skinfold width, fasting lipids insulin and glucose levels were measured and a standard (75-g) oral glucose-tolerance test was performed. RESULTS: Both groups had similar body mass index. Group I was younger than group II. Both systolic and diastolic blood pressure were significantly higher in group II than in group I. Hypertension was more prevalent in group II. Impaired glucose tolerance (from the oral glucose-tolerance test) prevalence did not differ between the groups, neither did the glycosylated haemoglobin nor fructosamine level. The insulinogenic index (ratio of the areas under the curve of the insulin to that of the glucose level during the oral glucose-tolerance test) was significantly higher in group II. Total and high-density lipoprotein-cholesterol levels were significantly higher in group II. In stepped multiple regression analysis, belonging to group II and having higher insulinogenic index predicted hypertension. CONCLUSIONS: This cross-sectional comparison of young, very lean Ethiopian immigrants found those with longer residence in Israel and higher insulinogenic index to have a threefold increase in the prevalence of hypertension in addition to acquiring higher cholesterol levels, indicating that in this ethnically distinct population environmental factors significantly affected the cardiovascular risk.

Adult↗
PubMed1994

Siesta and ambulatory blood pressure monitoring. Comparability of the afternoon nap and night sleep.

A prospective analysis of consecutive ambulatory blood pressure monitorings over a 5 month period identified 50 subjects (35%) who took an afternoon nap during the monitoring. The average duration of daytime sleep, as reported by the patients, was 1.8 +/- 0.6 h compared with the reported 7 +/- 2 h for nighttime sleep. Ambulatory blood pressure values during daytime awake periods were significantly higher compared with daytime sleep and nighttime sleep. The blood pressure decline during daytime sleep and nighttime sleep was similar. The pattern of blood pressure changes during daytime sleep was comparable in normotensive (n = 16), untreated (n = 10), and treated hypertensives (n = 24), irrespective of age, gender, and the level of blood pressure. The marked decline in blood pressure during daytime sleep suggests that sleep itself, rather than an endogenous circadian rhythm, is responsible for the blood pressure dip observed during both daytime sleep and nighttime sleep. Ignoring actual sleeping time in people who sleep during the day may greatly distort the day-night ambulatory blood pressure difference, when the latter is calculated on the basis of arbitrarily defined "day" and "night" periods.

Adolescent↗
PubMed1994

Nitrendipine improves glucose tolerance and deoxyglucose uptake in hypertensive rats.

We assessed the effect of the vasodilating calcium channel blocker nitrendipine on glucose tolerance in young spontaneously hypertensive rats (SHR) (n = 15). The nitrendipine group received 1 g/kg chow for 3 weeks. Untreated SHR (n = 14) served as controls. At 3 weeks body weight was comparable, whereas systolic blood pressure was 157 +/- 9 mm Hg in nitrendipine-treated rats versus 191 +/- 10 mm Hg in controls (mean +/- SD, P < .00001). Fasting glucose was 6.8 +/- 2.7 mmol/L in nitrendipine-treated versus 8.9 +/- 1.5 mmol/L in control rats (P < .03). An intravenous glucose tolerance test (300 mg/kg) showed plasma glucose levels at 2, 5, 15, and 30 minutes to be significantly lower in the nitrendipine-treated group versus controls (two-way ANOVA, P < .03). Glucose utilization was estimated by the uptake of [3H]deoxyglucose after its intravenous administration (2 microCi/100 g body wt) to instrumented awake animals. Heart and striated muscle uptake was, respectively, 7983 +/- 5812 and 951 +/- 731 cpm.microL/g.min in the nitrendipine-treated group versus 3532 +/- 2316 and 424 +/- 201 cpm.microL/g.min in controls (P < .02 and P < .04, respectively). [3H]Deoxyglucose plasma half-life and fasting and post-glucose load insulin levels were comparable in the two groups. The results show that nitrendipine improves glucose tolerance by increasing muscle glucose uptake. We suggest that glucose tolerance in SHR is influenced by muscle blood flow and can be improved by vasodilation.

Animals↗
PubMed1994

Moderate exercise improves glucose metabolism in uncontrolled elderly patients with non-insulin-dependent diabetes mellitus.

Exercise should be an integral part of the treatment in non-insulin-dependent (NIDDM) diabetic patients, yet most of these patients' performance is low, mainly because of their obesity and concomitant macrovascular disease. We studied the influence of a moderate exercise training on parameters of glucose control in NIDDM patients. Forty patients aged 56.6 +/- 6.6 years were assigned randomly according to age and sex into exercise and control groups. The exercise group trained for 45 min 3 times weekly for 12 weeks, while the control group did not change their lifestyle. At the end of the study the exercise group had a significant reduction in plasma levels of triglycerides, fructosamine and glycohemoglobin. The improvement in metabolic control persisted significantly in patients who continued to exercise at varying levels at home during 1 year of follow-up.

Aged↗
PubMed1993

Blood pressure, glucose, insulin and lipids of young Ethiopian recent immigrants to Israel and in those resident for 2 years.

OBJECTIVES: To determine influence of residence in Israel on blood pressure, glucose, insulin and lipids levels in recent and resident young Ethiopian immigrants, and to compare them with Israeli students. DESIGN: Young male Ethiopians, resident in Israel for < 3 months and residing in boarding schools, were compared, in a cross-sectional study, with those who had been living under the same conditions for 2 years. The food for both groups was provided from the same kitchen. A group of Israeli students served as an additional comparison group. METHODS: Body mass index, triceps skinfold width, sitting blood pressure and fasting glucose insulin, lipids and fructosamine levels were measured and a standard oral glucose tolerance test was performed, with glucose and insulin levels being measured 60 and 120 min after the load. RESULTS: Body mass index did not differ by much between the two Ethiopian groups, but was significantly lower in the Ethiopian groups than in the Israeli student group. Systolic (SBP) and diastolic blood pressure (DBP) were significantly higher in the resident immigrants than in the students, but the high-density lipoprotein-cholesterol, triglycerides, fructosamine and insulin response to oral glucose loading were all significantly lower, whereas the blood glucose response was actually higher. Resident immigrants had a significantly higher prevalence of hypertension. SBP and DBP correlated weakly (r = 0.25 and 0.24, respectively) with the sum of insulin after loading among the Ethiopian immigrants but not among the students. CONCLUSION: After 2 years' residence in Israel, young male Ethiopian immigrants acquire in parallel a rise in blood pressure and an increase in lipidaemia, insulinaemia and glucose response. However, the hypertensive subjects are not hyperinsulinaemic, with increases in insulinaemia accounting for only approximately 6% of blood pressure variability. The increase in the prevalence of hypertension therefore cannot be explained by dietary-induced insulinaemia alone.

Adult↗
PubMed1993

Acute hypertensive response to saline induced by vanadate, an insulinomimetic agent.

OBJECTIVE: To investigate whether the reported insulin-like properties of vanadate may have hypertensinogenic actions in Sabra rats. DESIGN: Comparison of [3H]-deoxyglucose muscle uptake as well as blood pressure and its response to acute volume expansion and pressors infusions in 16 vanadate-treated (VT) and 12 control rats. METHODS: Rats drank either tap water or 0.2 g/l vanadate for 4 weeks. A trace amount of [3H]-deoxyglucose was administered intravenously to evaluate its plasma half-life and tissue uptake. Intra-arterial blood pressure was recorded in response to acute intravenous saline (4 ml/100 g body weight) and to incremental bolus injections of noradrenaline and angiotensin II (Ang II). RESULTS: Skeletal muscle uptake of [3H]-deoxyglucose was significantly higher in VT than in control rats. There was no difference between the blood pressure of VT or control rats; however, 2 h after saline loading the mean intra-arterial blood pressure was significantly higher in VT than in control rats. The Ang II-induced blood pressure rise was also significantly higher in VT rats. CONCLUSION: The insulin-like activity of vanadate may be associated with salt-sensitive hypertension.

Animals↗
PubMed1993

Chronic exogenous hyperinsulinaemia without sugar supplementation: acute salt-sensitive hypertension without changes in resting blood pressure.

OBJECTIVE: To study the effects of chronic insulin administration without sugar supplementation on blood pressure and response to acute saline loading in normal rats. DESIGN: Comparison of blood pressure, insulin and glucose levels in 24 insulin-treated and 12 control rats on regular rat chow (not supplemented with sugar). METHODS: Sustained-release insulin implants (or sham implantation for the control rats) were administered subcutaneously. The sustained-release insulin implant size was gradually increased. Tail-cuff systolic blood pressure, insulin and glucose were measured twice a week for 8 weeks, after which intra-arterial blood pressure was recorded under resting conditions and 2 h after saline loading in seven insulin-treated and seven control rats. RESULTS: Insulin-treated rats had a 1.2- to twofold increase in insulin without hypoglycaemia, a small but significant increase in glucose levels being found at weeks 6 and 8. When the rats were killed (week 8) triglyceride and fructosamine levels were increased in the insulin-treated rats in comparison with controls. Neither tail-cuff systolic blood pressure nor resting intra-arterial blood pressure differed between the two groups. However, acute saline loading resulted in significantly higher blood pressure in the insulin-treated rats, without altering renal Na+ excretion. CONCLUSIONS: It is possible to produce mild hyperinsulinaemia without hypoglycaemia by gradually increasing subcutaneous sustained-release insulin administration without sugar supplementation. Such hyperinsulinaemia is associated with significantly higher glucose, fructosamine and triglyceride levels, and normal tail-cuff and resting intra-arterial blood pressure. Insulin may induce intolerance to acute volume loading that is not associated with Na+ retention.

Animals↗
PubMed1993

Disparate effects of exercise training on glucose tolerance and insulin levels and on ambulatory blood pressure in hypertensive patients.

OBJECTIVE: To assess the relationship of insulin levels and glucose tolerance to blood pressure in hypertension. DESIGN: An open, prospective trial of exercise training with ambulatory blood pressure monitoring and intravenous glucose tolerance testing before and after a 14-week training programme. PATIENTS: Twenty sedentary, untreated, non-obese, normoglycaemic individuals of both sexes with uncomplicated essential hypertension, of whom 16 completed the study. INTERVENTION: Fourteen weeks of supervised, low-intensity, group exercise of three 1-h sessions per week. MAIN OUTCOME MEASURES: Ambulatory and clinic blood pressure, and glucose and insulin responses to an intravenous glucose tolerance test. RESULTS: Maximal work capacity on a bicycle ergometer increased by 20% (P < 0.001); 24-h ambulatory blood pressure was 143 +/- 12/87 +/- 5 mmHg before and 142 +/- 13/87 +/- 7 mmHg after training. Clinic blood pressure decreased from 166 +/- 14/103 +/- 5 mmHg to 157 +/- 12/99 +/- 6 mmHg (P < 0.03). Two-way analysis of variance indicated significant decreases in both glucose (P < 0.04) and insulin (P < 0.03), fasting and throughout the intravenous glucose tolerance test. CONCLUSIONS: Although mild exercise reduced clinic blood pressure significantly, it did not affect ambulatory blood pressure despite a marked reduction in glucose and insulin levels. This finding argues against a determinant role of insulin in the 24-h maintenance of blood pressure in hypertensive patients under the conditions of the study.

Adult↗
PubMed1993

Comparison of verapamil and captopril in elderly hypertensive subjects: results of a randomized, double-blind, crossover study.

The effectiveness and tolerability of captopril and verapamil SR were compared in a double-blind, crossover study in 23 elderly hypertensives [15 males and 8 females, aged (mean +/- SEM) 68 +/- 1 years]. After 2 weeks of placebo run-in, patients were randomized to a starting dose of captopril, 12.5 mg b.i.d. or verapamil SR, 120 mg q.d. plus matched placebo of the opposite drug. Medication was titrated up over 6 weeks to a maximum dose of 75 mg of captopril or 360 mg of verapamil SR to achieve a sitting diastolic blood pressure of < 90 mm Hg. After 2 weeks of placebo washout, captopril and verapamil were crossed over. In the 20 patients who completed the study, the dose at the end of the respective treatment periods averaged 63 +/- 4 mg of captopril and 270 +/- 21 mg of verapamil SR. Blood pressure at the end of the run-in and washout placebo periods were comparable: 164 +/- 4/97 +/- 1 and 163 +/- 4/98 +/- 2 mm Hg, respectively. However, the blood pressure was significantly lower after verapamil, i.e., 147 +/- 4/86 +/- 2 mm Hg, than after captopril, i.e., 155 +/- 4/90 +/- 1 mm Hg (p < 0.05, ANOVA). There was no significant change in heart rate and laboratory parameters and no orthostatic hypotension. Captopril-treated patients reported a positive change in well being compared with placebo, although there was no overall difference between the drugs in any of the ten quality of life measurements. Three patients discontinued treatment, two because of constipation (verapamil) and one due to lack of efficacy (captopril).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1993

The prognosis of hypertensive disease of pregnancy accompanied by intrauterine growth retardation in relation to parity.

Twenty-two primiparous women with hypertensive disease of pregnancy (HDP) associated with intra uterine growth retardation (IUGR) were compared with 20 parous women in whom HDP associated with IUGR appeared for the first time in a second or a later pregnancy. Both groups of women were followed up for 10-13 years. The course of the disease among the parous women was more severe as compared to the primiparous women; the mean gestational age at the first increase in blood pressure and gestational age at delivery were significantly earlier in the parous group (33.3 weeks +/- 3.5 v.s. 35.3 +/- 3.2 weeks, p < 0.01, 36.2 weeks +/- 2.2 v.s. 37.6 +/- 1.9 p < 0.01 accordingly). Maternal indication for induction of labor because of uncontrollable hypertension was present in 77% of the cases in the parous group as compared to 31% in the primiparous group (p < 0.05). These complications were present in 66% of subsequent pregnancies in the parous group as compared with 31% in the primiparous group (p < 0.05). Chronic hypertension developed in 33% of the parous group as compared with 20% in the primiparous group. These differences show that the manifestation of HDP is more severe in women in whom HDP with IUGR occur for the first time in a second or a later pregnancy than in those in whom this complication occurs for the first time in a second or a later pregnancy than in those in whom this complication occurs for the first time in their first pregnancy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗