Duchenne electrocardiogram in myotonia dystrophica

The term “myopathic pattern” is applied to the electrocardiographic finding of R/S in lead V1 of more than 1.5 in association with deep Q and prominent R waves in leads V4-V6.¹ Such findings are characteristic of Duchenne's pseudohypertrophic muscular dystrophy and reportedly do not occur in other types of muscular dystrophy or myopathy.^2,3The purpose of this paper is to describe a case of myotonia dystrophica with the Duchenne electrocardiographic pattern.     

Relationship between insulin resistance, insulin secretion and insulin metabolism in simple obesity

The study was designed to evaluate whether the correlation occurring in simple obesity between insulin resistance and peripheral hyperinsulinemia corresponds to a relationship between insulin resistance and insulin overproduction by the pancreas. In addition, the study investigated the relation existing in simple obesity between insulin resistance and insulin metabolism. For these purposes, we measured and correlated: (1) insulin sensitivity, estimated by glucose disappearance rate from plasma after intravenous insulin injection; (2) insulin secretion by the pancreas, estimated by fasting C-peptide levels in peripheral blood; (3) insulin metabolism, estimated by means of C-peptide: insulin molar ratio in peripheral blood. Twenty-five subjects (20 females, five males) aged 21 to 59 years were studied. All were obese and had a normal glucose tolerance. Glucose disappearance rate from plasma after i.v. insulin injection averaged 3.65 +/- 0.42 mg/dl/min (mean +/- s.e.m.). Fasting C-peptide was 0.90 +/- 0.09 nmol/l. Fasting C-peptide: insulin molar ratio averaged 5.94 +/- 0.48. Negative correlations were found between glucose disappearance rates after i.v. insulin injection, ie, insulin sensitivity, and fasting concentrations of both insulin (r = -0.806, P less than 0.001) and C-peptide (r = -0.525, P less than 0.01). A positive relationship was found between glucose disappearance rate from plasma after i.v. insulin injection and fasting C-peptide: insulin molar ratio, ie, insulin metabolism (r = 0.707, P less than 0.001). We conclude that in simple obesity insulin overproduction by the pancreas is negatively related to insulin resistance, and insulin resistance and impaired insulin metabolism are strictly related phenomena.     

Relationships between insulin secretion, insulin metabolism and insulin resistance in mild glucose intolerance

The aim of this study was to evaluate whether the correlation between insulin resistance and peripheral hyperinsulinaemia existing in mild glucose intolerance corresponds to a relationship between insulin resistance and insulin overproduction by the pancreas. In addition, the possibility that insulin resistance is related to insulin metabolism was examined. Twenty five subjects with fasting normoglycaemia and an abnormal glucose response to the oral glucose tolerance test (OGTT) were studied. Insulin secretion by the pancreas was estimated by means of fasting C-peptide levels in peripheral blood. Insulin resistance was estimated by the rate of glucose disappearance from plasma after i.v. insulin injection. Insulin metabolism was estimated indirectly by the C-peptide: insulin molar ratio. A negative correlation was found between the glucose disappearance rate from plasma after i.v. insulin injection and fasting insulin levels (r = -0.677, p less than 0.001), but not fasting C-peptide concentrations (r = -0.164, p = NS). Glucose disappearance rate from plasma correlated positively with the C-peptide: insulin molar ratio (r = 0.626, p less than 0.001). These results suggest that in mild glucose intolerance insulin resistance and insulin secretion by the pancreas are not related phenomena, and that the defect responsible for insulin resistance might also be implicated in the impaired insulin metabolism.     

瘦素与胰岛素抵抗及糖代谢异常的关系

当供给人体的热量多于消耗量而以脂肪形式贮存在体内 ,使人体重量超过标准体重的 2 0 %时称为肥胖。肥胖患者常出现胰岛素抵抗 (ＩＲ) ,血浆胰岛素增高 ,外周组织对胰岛素的敏感性下降。研究表明 ,肥胖是糖代谢异常的重要诱发因素 ,与 2型糖尿病的发生相关。近年来发现 ,肥胖基因的蛋白质产物瘦素 (ｌｅｐｔｉｎ)能调节体重与能量代谢 ,但与ＩＲ及糖代谢异常的关系仍不十分清楚 ,本研究测定 84例受检者血清瘦素含量及其它有关指标 ,探讨瘦素与ＩＲ及糖代谢异常的关系。一、对象和方法1.对象 :84例受检者以往未发现患有糖尿病、甲状腺等内分…     

Myocardial metabolism and cardiac performance in obesity and insulin resistance

Obesity, insulin resistance, and their frequent complication of type 2 diabetes are risk factors for left ventricular diastolic dysfunction, systolic dysfunction, and clinical heart failure. Although obesity, insulin resistance, and diabetes are risk factors for coronary artery disease, and hence ischemic cardiomyopathy-related heart failure, there is increasing evidence that these three risk factors are implicated in the development of cardiac dysfunction not related to epicardial coronary disease. There are several mechanisms by which this triad may cause cardiac dysfunction, including alterations in myocardial metabolism, which may initially be adaptations but evolve into maladaptive responses over time. Recent advances in our understanding of these mechanisms will aid in the development of novel therapies, including metabolic manipulations that could prevent and treat cardiac dysfunction in patients with obesity, insulin resistance, and diabetes.