Ab initio modeling and molecular dynamics simulation of the alpha 1b-adrenergic receptor activation.

This work describes the ab initio procedure employed to build an activation model for the alpha 1b-adrenergic receptor (alpha 1b-AR). The first version of the model was progressively modified and complicated by means of a many-step iterative procedure characterized by the employment of experimental validations of the model in each upgrading step. A combined simulated (molecular dynamics) and experimental mutagenesis approach was used to determine the structural and dynamic features characterizing the inactive and active states of alpha 1b-AR. The latest version of the model has been successfully challenged with respect to its ability to interpret and predict the functional properties of a large number of mutants. The iterative approach employed to describe alpha 1b-AR activation in terms of molecular structure and dynamics allows further complications of the model to allow prediction and interpretation of an ever-increasing number of experimental data.

Results of a collaborative study of the EDNAP group regarding mitochondrial DNA heteroplasmy and segregation in hair shafts.

A collaborative exercise was carried out by the European DNA Profiling Group (EDNAP) in order to evaluate the distribution of mitochondrial DNA (mtDNA) heteroplasmy amongst the hairs of an individual who displays point heteroplasmy in blood and buccal cells. A second aim of the exercise was to study reproducibility of mtDNA sequencing of hairs between laboratories using differing chemistries, further to the first mtDNA reproducibility study carried out by the EDNAP group. Laboratories were asked to type 2 sections from each of 10 hairs, such that each hair was typed by at least two laboratories. Ten laboratories participated in the study, and a total of 55 hairs were typed. The results showed that the C/T point heteroplasmy observed in blood and buccal cells at position 16234 segregated differentially between hairs, such that some hairs showed only C, others only T and the remainder, C/T heteroplasmy at varying ratios. Additionally, differential segregation of heteroplasmic variants was confirmed in independent extracts at positions 16093 and the poly(C) tract at 302-309, whilst a complete A-G transition was confirmed at position 16129 in one hair. Heteroplasmy was observed at position 16195 on both strands of a single extract from one hair segment, but was not observed in the extracts from any other segment of the same hair. Similarly, heteroplasmy at position 16304 was observed on both strands of a single extract from one hair. Additional variants at positions 73, 249 and the HVII poly(C) region were reported by one laboratory; as these were not confirmed in independent extracts, the possibility of contamination cannot be excluded. Additionally, the electrophoresis and detection equipment used by this laboratory was different to those of the other laboratories, and the discrepancies at position 249 and the HVII poly(C) region appear to be due to reading errors that may be associated with this technology. The results, and their implications for forensic mtDNA typing, are discussed in the light of the biology of hair formation.

Spurious hyperphosphatemia in a patient with alteplase-locked central venous catheter.

Alteplase has been shown to be effective in preventing central venous access clotting in patients on hemodialysis. Because of a high phosphorus content in its excipient, it can inadvertently contaminate blood samples, leading the physician in care of the patient to erroneously increase dialysis time or change diet in order to control the pseudo-hyperphosphatemia.

Coronary artery disease screening in diabetic patients: how good is guideline adherence?

INTRODUCTION: Diabetic patients are at high risk for coronary artery disease (CAD), which is the leading cause of death in this population. The Swiss Society of Endocrinology-Diabetology (SSED) recommends CAD screening for diabetic patients with > or = 2 additional cardiovascular risk factors (CVRF), by stress echocardiography (SE) or myocardial perfusion imaging (MPI). The aim of this study was to assess the application of these guidelines and the treatment of CVRF in the diabetes outpatient clinics of the five Swiss University Hospitals. METHODS: The study was initiated in Lausanne and the study questionnaires were circulated to the endocrinologists of the five Swiss University Hospitals. Practitioners were asked to include consecutive patients attending the diabetes outpatient clinics over one month. Prevalence of CAD, screening methods for CAD, prevalence of CVRF, biological analyses over the last 6 months and medical therapy were recorded. RESULTS: A total of 302 subjects were included. The mean age was 53 +/- 14 years, 68% had type 2 diabetes, 27% type 1 and 5% other types. Among T2DM with > or = 2 CVRF, 45% were screened for CAD according to SSED guidelines. In T2DM 25% had blood pressure < or = 130/80 mm Hg, 15% a lipid profile within target, 23% HbA1c < or = 7.0%. Overall, 2% achieved all 3 targets. CONCLUSIONS: Only 45% of T2DM with > or = 2 CVRF were screened for CAD according to SSED guidelines and 2% of T2DM had proper control over all CVRF. Efforts are still necessary to improve CAD prevention and screening of diabetic patients in Swiss University Hospitals.