Prolonged cardiac repolarization causes fatal cardiac arrhythmias. There is evidence that these contribute to sudden death associated with nocturnal hypoglycemia in young people with diabetes. We measured cardiac repolarization (QT interval [QTc] and QT dispersion [QTd]) during experimental hypoglycemia with and without ␤-blockade and potassium infusion to establish possible mechanisms. Two groups of 10 nondiabetic men (study 1 and study 2) each underwent four hyperinsulinemic clamps: two euglycemic (5 mmol/l) and two hypoglycemic (5 mmol/l and 2.5 mmol/l for 60 min each). Study 1 was performed with and without potassium infusion to maintain normal concentrations and study 2 with and without ␤-blockade (atenolol, 100 mg/day for 7 days). QTd was unchanged during euglycemia but increased during hypoglycemia (55 ms, P < 0.0001 vs. baseline), which was prevented by potassium (6 ms, P ‫؍‬ 0.78). QTc increased significantly during hypoglycemia alone (67 ms, P < 0.0001) and during potassium replacement (46 ms, P ‫؍‬ 0.02). In study 2, the increase in QTd during hypoglycemia (68 ms, P < 0.0001) was prevented by ␤-blockade (3 ms, P ‫؍‬ 0.88). The increase in QTc during hypoglycemia (55 ms, P < 0.0001) was prevented by ␤-blockade (1 ms, P ‫؍‬ 0.98). Our data indicate that hypoglycemia causes an acquired long QT syndrome. Sympathoadrenal stimulation is the main cause, through mechanisms that involve but are not limited to catecholamine-mediated hypokalemia. These abnormalities are prevented by selective ␤-blockade. Diabetes

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Spinal cord involvement occurs early in DPN. There is also a significant relation between reduction in SCAI and neurophysiological assessments of DPN.

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OBJECTIVE -The pathogenesis of painful diabetic neuropathy (PDN) is not clear. Following our in vivo observations of increased sural nerve epineurial blood flow in patients with PDN, we investigated the cutaneous microcirculation of the foot by laser Doppler flowmetry to determine if the epineurial findings were just confined to the nerve or more widespread in other vascular beds.RESEARCH DESIGN AND METHODS -We measured foot skin vasodilator responses to acetylcholine (Ach) and sodium nitroprusside (SNP) and vasoconstrictor responses to sympathetic (deepest possible gasp) stimulation in 5 healthy control subjects, 10 nonneuropathic diabetic (NND) patients, 10 diabetic patients with painless neuropathy (PLDN), and 8 diabetic patients with PDN.RESULTS -In PDN, there were significantly reduced responses to Ach (ANOVA P ϭ 0.003) and vasoconstrictor inspiratory gasp (ANOVA P Ͻ 0.001) but not to SNP (NS). Post hoc analysis showed significant differences in Ach-induced vasodilation between PDN and nondiabetic control subjects (P Ͻ 0.05) as well as between PDN and NND (P Ͻ 0.05) but not PDN and PLDN (NS). There were no significant differences for SNP-induced vasodilation. However, there were significant differences in the vasoconstrictor response between PDN and control, NND, and PLDN (P Ͻ 0.01).CONCLUSIONS -We found an impairment of cutaneous endothelium-related vasodilation and C-fiber-mediated vasoconstriction in PDN. Inappropriate local blood flow regulation may have a role in the pathogenesis of pain in diabetic neuropathy. Prospective studies are required to determine the temporal relationship of these changes in relation to the emergence of neuropathic pain. Diabetes Care 30:655-659, 2007D iabetic peripheral neuropathy is one of the most common long-term complications of diabetes (1) and is associated with cardiovascular risk factors and mortality (2,3). Pain is one of the manifestations of diabetic neuropathy that often prompts the patient to seek medical attention and occurs in ϳ30% of patients with diabetic neuropathy (4).Painful diabetic neuropathy (PDN) is difficult to treat and results in depression and a marked reduction in quality of life (5). Despite considerable research, a complete understanding of the mechanisms of neuropathic pain remains elusive. Consequently, many patients respond poorly to drug therapies. Elucidation of the pathophysiological mechanisms underlying PDN may lead to more effective treatments (3).Many years ago, Archer et al. (6) showed that diabetic patients with PDN have altered blood flow patterns in the lower limbs. More recently, we found an increase in sural nerve epineurial blood flow in patients with PDN (7). We have also shown that patients with severe pain due to insulin neuritis have abnormal epineurial nutrient vessel anatomy and increased epineurial shunt flow, which may lead to a reduction in endoneurial nutritive blood flow (8). These observations linking PDN with alterations in blood flow are supported by two recent trials that have demonstrated significant benefits of...

Research has focused on improvement of the quality of life of stroke patients. Gait detection, kinematics and kinetics analysis, home-based rehabilitation and telerehabilitation are the areas where there has been increasing research interest. The paper reviews position-sensing technologies and their application for human movement tracking and stroke rehabilitation. The review suggests that it is feasible to build a home-based telerehabilitation system for sensing and tracking the motion of stroke patients.

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