E. Moberg

Arterial, arterialized venous, venous and capillary blood glucose measurements in normal man during hyperinsulinaemic euglycaemia and hypoglycaemia

SummaryThe purpose of this study was to evaluate the effectiveness of the warm-air box method on the arterialization of venous blood during euglycaemia and hypoglycaemia. Six healthy male volunteers were studied using an i.v. infusion of insulin (144 mU·kg−1·h−1). Arterial blood glucose was clamped at the baseline level for the first 30 min and subsequently reduced to 3.2 and to 2.5 mmol/l for 20 min. At each stage, including prior to insulin infusion, arterial, arterialized venous (heating the hand in a warm-air box set to 55–60°C), venous and capillary blood samples were taken simultaneously for analyses of blood glucose and oxygen saturation (not for capillary blood). The oxygen saturations in arterialized blood were approximately 3% below the arterial values. The arterial-arterialized difference of blood glucose was about 0.1 mmol/l (the 95% confidence interval: from −0.19 to 0.41 mmol/l), which tended to correlate with the difference in oxygen saturations between the arterial and arterialized blood samples (r=0.25, p=0.08). During the test the forearm venous blood oxygen saturation increased by 9% and the arteriovenous difference in blood glucose ranged from 0.2 to 0.5 mmol/l which correlated significantly with the difference in oxygen saturations (r=0.48, p<0.001). Capillary glucose was similar to the arterialized value. Rectal temperature was stable during the experiment. We conclude that the heated hand technique using the warm-air box sufficiently arterializes venous blood so that the glucose measurement in the arterialized blood provides a reasonable estimate of the arterial value and that the venous blood from the contralateral forearm is also markedly arterialized, probably reflecting a vasodilator effect of heating.

Protracted glucose fall in subcutaneous adipose tissue and skeletal muscle compared with blood during insulin-induced hypoglycaemia

SummaryThe absolute glucose concentrations in subcutaneous adipose tissue and skeletal muscle were determined with microdialysis in 10 normal-weight, healthy subjects during a standardized hyperinsulinaemic hypoglycaemic clamp. The concentration of tissue dialysate glucose was measured in 15-min fractions and compared with that in arterialized venous plasma. Insulin (0.15 U · kg-1· h-1) was infused i. v. to lower the plasma glucose level to 2.5 mmol/1 over 30 min. This level was maintained for 30 min by using a variable glucose infusion. Thereafter, the insulin infusion was stopped and the plasma glucose level was gradually increased to baseline levels over 120 min. During a 60-min basal period, the glucose levels in muscle were 0.6 mmol/1 lower than those in plasma (p = 0.002), whereas the levels in adipose tissue and plasma were similar. The glucose nadirs in muscle (1.6 ± 0.1 mmol/1) and adipose tissue (2.0 ± 0.1 mmol/1) were significantly lower than that in plasma (2.4 ± 0.1 mmol/1) (p = 0.001 and 0.02, respectively), and the time-to-nadir was substantially longer in muscle (69 ± 5 min) and adipose tissue (57 ± 2 min) than in plasma (39 ± 3 min) (p = 0.0004). When the insulin infusion was stopped, the increases in adipose tissue and muscle glucose concentrations were delayed by approximately 25 and 45 min, respectively, as compared to the increase in plasma glucose. Thus, it seems that glucose measurements in adipose tissue and muscle more adequately reflect overall tissue homeostasis than do measurements in blood and that clinically relevant tissue glucopenia may be overlooked by conventional blood glucose measurements.

Rates and predictors of hypoglycaemia in 27 585 people from 24 countries with insulin-treated type 1 and type 2 diabetes: the global HAT study.

To determine the global extent of hypoglycaemia experienced by patients with diabetes using insulin, as there is a lack of data on the prevalence of hypoglycaemia in developed and developing countries.

Acute mental stress impairs insulin sensitivity in IDDM patients

SummaryThe effect of acute mental stress on insulin sensitivity was evaluated in ten IDDM patients, studied on two occasions (test day and control day) in random order and separated by a period of 1–3 weeks. Mental stress was evoked by a modified filmed version of Stroops CWT for 20 min. On the control day, the patients were resting quietly during the corresponding period. Insulin sensitivity was estimated by an insulin (0.4 mU · kg−1 · min−1)-glucose (4.5 mg · kg−1 · min−1)-infusion test (IGIT) for 6.5 h. Mental stress evoked significant responses for adrenaline, cortisol and GH, their respective peak values being 0.27 ± 0.05 nmol/l, 426 ± 27 nmol/l and 7.6 ± 1.8 μg/l, as well as increases in systolic and diastolic blood pressure and pulse rate The steady-state blood glucose levels, i.e. the mean blood glucose levels 3–6.5 h after the start of the IGIT, were significantly higher after stress, compared with those on the control day, 10.6 ± 1.5 vs 8.7 ± 1.4 mmol/l, p = 0.01, demonstrating impairment of the insulin sensitivity by mental stress. It is concluded that acute mental stress induces a state of insulin resistance in IDDM patients, which can be demonstrated by an IGIT to appear 1 h after maximal stress and to last more than 5 h.

Day-to-day variation of insulin sensitivity in patients with type 1 diabetes: role of gender and menstrual cycle.

The aim of the present study was to compare the day‐to‐day variations of the insulin sensitivity in male and female Type 1 diabetic patients and to assess the insulin sensitivity in the follicular and luteal phases of the menstrual cycle. Ten male and 20 female Type 1 diabetic patients participated in the study. The insulin sensitivity was assessed by the insulin (0.4 mU kg−1min−1)‐glucose/(4.5 mg kg−1min−1)‐infusion test (IGIT). In 5 of the female patients, a simultaneous i.v. influsion of somatostatin (100 μgh−1) was given (SIGIT). Each patient was studied twice, with 2 weeks separating the two tests. The day‐to‐day variations of the insulin sensitivity were almost identical in the male and female patients, the coefficients of variation being 13% in both groups. In 15 of the female patients, ovulation occurred. In these women, the mean blood‐glucose levels between 120 and 240 min after the onset of the IGIT/SIGIT were 9.8 ± 1.1 mmol l−1 in the follicular phase and 10.3 ± 1.0 mmol l−1 in the luteal phase, n.s. (95% confidence interval for the difference (luteal‐follicular) −0.8–1.9 mmol l−1). Although the present study cannot exclude minor changes of insulin sensitivity during the menstrual cycle, our results suggest that the changes of the metabolic control during the menstrual cycle, experienced by many women with Type 1 diabetes, are largely attributable to mechanisms other than variations of insulin sensitivity.

Regional variations in definitions and rates of hypoglycaemia: findings from the global HAT observational study of 27 585 people with Type 1 and insulin-treated Type 2 diabetes mellitus

To determine participant knowledge and reporting of hypoglycaemia in the non‐interventional Hypoglycaemia Assessment Tool (HAT) study.