Objective

The prevention of progression of arterial disease and diabetes (POPADAD) trial: factorial randomised placebo controlled trial of aspirin and antioxidants in patients with diabetes and asymptomatic peripheral arterial disease

Summary and conclusionsThe immediate heart-rate response to standing was measured in 22 normal controls and 25 patients with diabetes, 15 of whom had autonomic neuropathy. The response in the controls and patients without autonomic neuropathy was characteristic and consistent, with tachycardia maximal at around the 15th beat and relative bradycardia maximal at around the 30th beat. The diabetics with autonomic neuropathy, however, showed a flat response. In three controls the response was abolished with intravenous atropine but not with propranolol, showing that it is mediated through the vagus.

Mycobacteriophages are viruses that infect mycobacterial hosts such as Mycobacterium smegmatis and Mycobacterium tuberculosis. All mycobacteriophages characterized to date are dsDNA tailed phages, and have either siphoviral or myoviral morphotypes. However, their genetic diversity is considerable, and although sixty-two genomes have been sequenced and comparatively analyzed, these likely represent only a small portion of the diversity of the mycobacteriophage population at large. Here we report the isolation, sequencing and comparative genomic analysis of 18 new mycobacteriophages isolated from geographically distinct locations within the United States. Although no clear correlation between location and genome type can be discerned, these genomes expand our knowledge of mycobacteriophage diversity and enhance our understanding of the roles of mobile elements in viral evolution. Expansion of the number of mycobacteriophages grouped within Cluster A provides insights into the basis of immune specificity in these temperate phages, and we also describe a novel example of apparent immunity theft. The isolation and genomic analysis of bacteriophages by freshman college students provides an example of an authentic research experience for novice scientists.

Glucokinase (GCK) is a key regulatory enzyme in the pancreatic ␤-cell and catalyzes the rate-limiting step for ␤-cell glucose metabolism. We report two novel GCK mutations (T65I and W99R) that have arisen de novo in two families with familial hypoglycemia. Insulin levels, although inappropriately high for the degree of hypoglycemia, remain regulated by fluctuations in glycemia, and pancreatic histology was normal. These mutations are within the recently identified heterotropic allosteric activator site in the theoretical model of human ␤-cell glucokinase. Functional analysis of the purified recombinant glutathionyl S-transferase fusion proteins of T65I and W99R GCK revealed that the kinetic changes result in a relative increased activity index (a measure of the enzyme's phosphorylating potential) of 9.81 and 6.36, respectively, compared with wild-type. The predicted thresholds for glucose-stimulated insulin release using mathematical modeling were 3.1 (T65I) and 2.8 (W99R) mmol/l, which were in line with the patients' fasting glucose. In conclusion, we have identified two novel spontaneous GCK-activating mutations whose clinical phenotype clearly differs from mutations in ATP-sensitive K ؉ channel genes. In vitro studies confirm the validity of structural and functional models of GCK and the putative allosteric activator site, which is a potential drug target for the treatment of type 2 diabetes.