Twenty-four-hour blood pressure and heart rate measurements were carried out in 14 newly diagnosed diabetics and in 28 diabetics with 5-13 years' duration of the disease; 8 healthy children were used as controls. Mean arterial blood pressure increased at night in 5, decreased slightly (less than 10%) in 5 and decreased markedly (more than 10%) in 18 diabetics with longer duration of the disease. The diurnal-nocturnal differences in heart rates were significantly lower in diabetics with relative "nocturnal hypertension" compared to the control group (p < 0.05). A significant negative correlation was found between maximal arterial blood pressure during physical exercise and the diurnal-nocturnal differences in mean arterial blood pressure in diabetics (r = -0.58; p < 0.02). In conclusion, we found elevated nocturnal blood pressure in a subgroup of children with longer duration of diabetes and without increased albumin excretion. However, longitudinal studies of blood pressure profiles are needed to identify the candidates for diabetic vasculopathy among diabetic children.

To evaluate the efficacy of the acute-physical-stress response, plasma catecholamine and lactate levels, serum electrolytes, fructosamine, blood glucose and acid-base status were measured in insulin-dependent diabetes mellitus (IDDM) children and the data compared to those of healthy controls. Four groups were studied: group 1, healthy controls; group 2, newly diagnosed diabetic patients with an IDDM duration of 2-4 weeks; group 3, with an IDDM duration of 5-7 years; group 4, with an IDDM duration of 10-13 years. According to their fructosamine levels, IDDM children were in a well-controlled metabolic state. The physical stress was induced by 1.5-1.7 W/kg/ 10 min bicycle ergometer determined by a target pulse rate of 170/min. IDDM children exhibited pronounced lactic acidosis under stress (pH: group 2, 7.27 ± 0.07; group 3, 7.28 ± 0.05; group 4, 7.20 ± 0.04, vs. group 1; 7.34 ± 0.03). Baseline plasma norepinephrine and epinephrine levels showed a significant decrease parallel to the duration of IDDM. Stress induced an increase in the concentration of norepinephrine in each group, but the elevation was significantly higher in the IDDM children versus the controls. A significant negative correlation was found between pH and maximal plasma norepinephrine levels (y = 7.3-0.006x, r = -0.46, p < 0.02). Stress resulted in blood glucose elevation in 13 patients regardless of their pre-exercise blood glucose levels, ▵blood glucose values of these patients showed a significant correlation with ▵norepinephrine and epinephrine values (for norepinephrine: y = -2.7 + 5.2x, r = 0.66, p < 0.01; for epinephrine: y = 0.21 + 0.5x, r = 0.6, p < 0.05). Our data show that acute physical stress induces severe lactic acidosis and a more pronounced sympathetic-adrenergic acitivity in children with IDDM.

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