A metropolitan experience with infrainguinal revascularization. Operative risk and late results in northeastern Ohio

Despite being of fundamental importance, the late results of major arterial reconstruction rarely have been documented throughout a large metropolitan area. In this study of 932 patients entered into the computer registry of the Cleveland Vascular Society, 19 surgeons representing 13 community hospitals and referral centers in Cleveland and Akron report the intermediate-term outcome during a mean interval of 35 months after infrainguinal lower extremity revascularization performed in northeastern Ohio from 1978 through 1982. Operative risk (5%), the early amputation rate (7%), and actuarial 5-year survival (48% to 55%) for patients with rest pain or tissue necrosis were significantly worse (p less than 0.05) than comparable figures (0.6%, 0%, and 77%, respectively) for others who underwent procedures for disabling claudication. Although both materials had similar success above the knee, the cumulative 3-year patency rate of autogenous vein bypass to the distal popliteal (69% to 88%; p less than 0.05) and tibioperoneal arteries (43%; 0.05 less than p less than 0.1) was superior to the results of polytetrafluoroethylene grafts (32% to 50% and 19%, respectively). Moreover, polytetrafluoroethylene grafts required reoperations at three times the rate of vein grafts to maintain limb salvage.     

Regional cerebral glucose transport in insulin-dependent diabetic patients studied using [11C]3-O-methyl-D-glucose and positron emission tomography

Regional cerebral [11C]3-O-methyl-D-glucose ([11C]MeG) uptake kinetics have been measured in five insulin-dependent diabetic patients and four normal controls using positron emission tomography (PET). Concomitant measurement of regional cerebral blood volume and CBF enabled corrections for the presence of intravascular [11C]MeG signal in cerebral regions of interest to be carried out, and regional cerebral [11C]MeG unidirectional extraction fractions to be computed. Four of the five diabetic subjects were studied with their fasting plasma glucose level clamped at a normoglycaemic level (4 mM), and four were studied at hyperglycaemic plasma glucose levels (mean 13 mM). The four diabetic subjects whose fasting plasma glucose levels were clamped at a normoglycaemic level of 4 mM had mean fasting whole-brain, cortical, and white matter [11C]MeG extraction fractions of 15, 15, and 16%, respectively, values similar to those found for the four normal controls (whole brain, 14%; cortex, 13%; white matter, 17%). Mean regional cerebral [11C]MeG extraction fractions were significantly reduced in diabetic subjects during hyperglycaemia whether their plasma insulin levels were undetectable or whether they were raised by continuous intravenous insulin infusion. Such a reduction in [11C]MeG extraction under hyperglycaemic conditions can be explained entirely in terms of increased competition between [11C]MeG and D-glucose for the passive facilitated transport carrier system for hexoses across the blood-brain barrier (BBB). It is concluded that the number and affinity of D-glucose carriers present in the BBB are within normal limits in treated insulin-dependent diabetic subjects. In addition, insulin appears to have no effect on the transport of D-glucose across the BBB.     

Fasting insulin and left ventricular mass in hypertensives and normotensive controls.

The mechanism by which increased left ventricular (LV) mass leads to increased coronary heart disease morbidity and mortality is unknown. We evaluated the relation between fasting insulin and echocardiographic LV mass in hypertensives off medication and normotensive controls, controlling the analyses for blood pressure (BP) and body mass index (BMI). Fasting insulin (p = 0.0217) was the most significant predictor of LV mass in hypertensives, while BMI (p = 0.0265) and diastolic BP (p = 0.0159) were the only significant predictors of LV mass in controls. The relation between fasting insulin and LV mass was not confounded by obesity in hypertensives, but obesity and fasting insulin may interact to predict LV mass.     

Restoring and preserving trust in biomedical research.

Recent media depictions of the dangers of biomedical research have fueled public and regulatory scrutiny of academic research institutions. The authors argue that if these institutions are to preserve the trust that the public has historically bestowed upon them, they must go beyond mere compliance with regulatory mandates. Several steps are suggested that institutions can take to strengthen and supplement ongoing compliance efforts, steps the authors believe will bolster the public's confidence in the integrity of academic research institutions. These steps grow out of the authors' analysis of three key components of institutional trustworthiness: (1) shared goals between research institutions and the communities they serve, (2) robust institutional oversight of research activities, and (3) training programs that build professional character. The authors' recommendations include the use of research advisory councils to assure the public that research goals reflect community interests, more collaborative relationships between institutional review boards and members of investigative teams, and educational programs that emphasize the importance of professional integrity in biomedical research. These efforts will help preserve public confidence that an institution's research priorities are appropriate and that the research it conducts is ethical. Preserving this public trust is central to the long-term success of biomedical research and the institutions in which such research takes place.     

Heat shock protein hsp72 induction in cortical and striatal astrocytes and neurons following infarction

Transient global and transient focal ischemia induced the 72 kDa heat shock protein (hsp72) in neurons in cortex, striatum, and other regions known to be injured during transient ischemia. A novel finding was the induction of hsp72 in islands (cylinders in three dimensions) of cells composed of astrocytes around the perimeter and neurons in the interior. Since histology showed pale staining in these regions, it is proposed that these islands represent areas of focal infarction in the distribution of small cortical and lenticulostriate arteries. Although the factors responsible for hsp72 induction during ischemia and infarction are unknown, these results suggest differences in mechanisms of hsp72 induction in astrocytes compared to neurons.