Fine-tuned photochromic sulfonylureas for optical control of beta cell Ca2+ fluxes

We previously developed, synthesized and tested light-activated sulfonylureas for optical control of KATP channels and pancreatic beta cell activity in vitro and in vivo. Such technology relies on installation of azobenzene photoswitches onto the sulfonylurea backbone, affording light-dependent isomerization, alteration in ligand affinity for SUR1 and hence KATP channel conductance. Inspired by molecular dynamics simulations and to further improve photoswitching characteristics, we set out to develop a novel push-pull closed ring azobenzene unit, before installing this on the sulfonylurea glimepiride as a small molecule recipient. Three fine-tuned, light-activated sulfonylureas were synthesized, encompassing azetidine, pyrrolidine and piperidine closed rings. Azetidine-, pyrrolidine- and piperidine-based sulfonylureas all increased beta cell Ca2+ -spiking activity upon continuous blue light illumination, similarly to first generation JB253. Notably, the pyrrolidine-based sulfonylurea showed superior switch OFF performance to JB253. As such, third generation sulfonylureas afford more precise optical control over primary pancreatic beta cells, and showcase the potential of pyrrolidine-azobenzenes as chemical photoswitches across drug classes.

Successful treatment of life-threatening Evans syndrome due to antiphospholipid antibody syndrome by rituximab-based regimen: a case with long-term follow-up

An association of antiphospholipid antibody syndrome with antibodies directed against either phospholipids or plasma proteins strongly suggest that B-cell dysfunction may be involved in its pathogenesis. Antiphospholipid antibody syndrome with autoimmune cytopenias shows a poor response rate to conventional treatment with anticoagulants, glucocorticosteroids, immunosuppressive agents, intravenous immunoglobulin or plasmapheresis. We report a case of life-threatening antiphospholipid antibody syndrome with Evans syndrome receiving successful multimodal treatment including anti-CD20 monoclonal antibody rituximab with long-term follow-up.

Sequencing, high-level expression and phylogeny of the pyrophosphate-dependent phosphofructokinase from the thermophilic spirochete Spirochaeta thermophila

The full-length gene encoding a 554-amino-acid, active pyrophosphate-dependent phosphofructokinase from Spirochaeta thermophila was cloned and sequenced using a combination of degenerate and inverse PCR, and the enzyme expressed to a high level in Escherichia coli. The recombinant enzyme, with a calculated molecular mass of 61 kDa, was purified to near homogeneity and found to be similar to the purified native enzyme for most properties examined. Phylogenetic analysis demonstrated a close relationship between the thermophilic S. thermophila phosphofructokinase and the large beta-subunits of the phosphofructokinases from Borrelia burgdorferi and Treponema pallidum.

Early magnetic resonance imaging of brainstem lesions after severe head injury

OBJECT

The availability of magnetic resonance (MR) imaging data obtained in comatose patients after head injury is scarce, because MR imaging is somewhat cumbersome to perform in patients requiring ventilation and because, in the first hours after injury, its relevance is clearly inferior to computerized tomography (CT) scanning. The authors assessed the value of MR imaging in the early postinjury period.

METHODS

In this prospective study MR imaging was performed in 61 consecutive patients within 7 days after they suffered a severe head injury. An initial CT scan had already been obtained. To understand the clinical significance of the lesions whose morphological appearance was identified with MR imaging, brainstem function was assessed by registration of somatosensory and auditory evoked potentials. Brainstem lesions were visualized in 39 patients (64%). Bilateral pontine lesions proved to be 100% fatal and nonbrainstem lesions carried a mortality rate of 9%. In singular cases circumstances allowed for a clear clinical distinction between primary and secondary brainstem lesions. On MR imaging all lesions were hyper- and hypointense after intervals longer than 2 days. Within shorter intervals (< 2 days) after the injury, primary lesions appeared isointense on MR imaging. In one secondary brainstem lesion there were no traces of blood.

CONCLUSIONS

Because mean intracranial pressure (ICP) levels in patients without brainstem lesions were similar to those in patients with brainstem lesions, the authors conclude that it was not mainly increased ICP that accounted for the high mortality rates in patients with brainstem lesions. The authors also conclude that brainstem lesions are more frequently found in severe head injury than previously reported in studies based on neuropathological or CT scanning data. Early MR imaging after head injury has a higher predictive value than CT scanning.

Influence of starch fermentation on bile acid metabolism by colonic bacteria

Secondary bile acids (BA) may be involved in the pathogenesis of colorectal cancer. In vivo, starch malabsorption has been shown to reduce fecal excretion of secondary BA. The present in vitro study was performed to investigate the effect of starch fermentation on BA metabolism by colonic bacteria. Fecal samples of healthy volunteers were incubated in anaerobic batch cultures for 48 hours with the primary bile acids cholic (0.6 g/l) and chenodeoxycholic acid (0.4 g/l). Media were starch free or enriched with starch (10 g/l). The pH was controlled and held at 6 or 7. In the starch-free incubations, secondary BA were rapidly formed, and degradation of primary to secondary BA was complete within 24 hours. The formation of secondary BA was partially inhibited by the addition of starch to the media. This effect was stronger at pH 6 than at pH 7. Starch was rapidly and completely fermented. In conclusion, this study showed that formation of secondary BA by fecal bacteria is inhibited when starch is simultaneously fermented, an effect that is mainly, but not completely, explained by reduction of pH.

Ergonomic evaluation of a wheelchair for transfer of disabled passengers at a large airport

Transferring disabled passengers to the aircraft, both arriving and departing, is one passenger service at a big airport. We use different ergonomic research methods (registration of heart rate, AET job analysis as well as a standardized questionnaire) to evaluate the present wheelchair design. Due to e.g. the high wheelchair backrest, the forces needed to handle the chair and other facts, the current wheelchair causes a strain bottleneck. The results of the AET analysis and the rating of the perceived exertion confirm this finding. A redesigned wheelchair based on ergonomic principles, which reduces stress on the employees and offers more comfort to disabled passengers, is presented.