Heparin-induced thrombocytopenia: pathophysiology

We have used computer modeling of insulin 3-D structure and experimental data about action of site point mutation on insulin activity to design functionally important domain with signaling activity and synthesized peptide than might be sufficient for the binding to insulin receptor. The designed and synthesized peptide consist of ten residues and may be obtained in two forms: oxidized and reduced (with or without disulfide bond). The synthesized decapeptide peptide represents functionally important site for binding to the insulin receptor. Amino acid residues at position 1-8 correlate with B-chain of insulin at position (B19-B26). Residues at position 9.10 correlate with A-chain at position A-10-A21. This peptide was tested with cell culture L-929 (glucose uptake) in comparison with bioactive commercial peptide (R-G-FF) and insulin. It was shown that synthesized peptide exhibit biological activity at molar concentration 0.01-1 mkM. Our results successfully demonstrate the synthetic insulin fragment have insulin-like biological activity.     

Explosive shock-compression processing of titanium aluminide/titanium diboride composites

Explosive shock-compression processing is used to fabricate Ti₃Al and TiAl composites reinforced with TiB₂. The reinforcement ceramic phase is either added as TiB₂ particulates or as an elemental mixture of Ti + B or both TiB₂ + Ti + B. In the case of fine TiB₂ particulates added to TiAl and Ti₃Al powders, the shock energy is localized at the fine particles, which undergo extensive plastic deformation thereby assisting in bonding the coarse aluminide powders. With the addition of elemental titanium and boron powder mixtures, the passage of the shock wave triggers an exothermic combustion reaction between titanium and boron. The resulting ceramic-based reaction product provides a chemically compatible binder phase, and the heat generated assists in the consolidation process. In these composites the reinforcement phase has a microhardness value significantly greater than that of the intermetallic matrix. Furthermore, no obvious interface reaction is observed between the intermetallic matrix and the ceramic reinforcement.     

Adenovirus-mediated gene transfer to liver grafts: an improved method to maximize infectivity

A patient motion-related artefact is one of the most important artefacts in single-photon emission tomography (SPET) imaging. This study evaluated the effect of the number and configuration of SPET detectors on motion artefacts. The following acquisition conditions were simulated based on original 360 degrees projection images: (1) single-detector 180 degrees rotation (S180), (2) a dual-detector rectangular (L-shaped) 180 degrees acquisition (D180L), (3) dual-detector cameras mounted opposite each other with 360 degrees acquisition (D360) and (4) triple-detector 360 degrees acquisition (T360). The motion artefacts were introduced using a syringe and a myocardial phantom. Clinical cases with technetium-99m methoxyisobutylisonitrile and thallium-201 studies were analysed to confirm the validity of this phantom simulation. The effect of continuous alternate rotation acquisition and summing the projections on the reduction of motion artefacts was investigated in each model. The effect of motion depended on the number and the configuration of the SPET detectors. A 1-pixel (6.4 mm) motion in the S180, D180L and D360 models generated only slight artefacts, and a 2-pixel motion led to an apparent decrease in activity or created hot areas in the myocardium. On the other hand, a T360 rotation created few artefacts even with a 2-pixel motion of the last quarter of the projections. Despite the difference in attenuation with 201Tl and 99mTc, similar artefact patterns were observed with both radionuclides in selected patient model studies. Continuous alternate rotation could reduce artefacts caused by less than a 2-pixel motion. In conclusion, calculating the average of the sum of the projections of triple-detector 360 degrees rotations with alternate rotation is the best method to minimize motion artefacts. This "averaging" effect of motion artefacts is a key to this simulation.     

Rapid biomineralization of chitosan microparticles to apply in bone regeneration

The aim of this study was to prepare bone like mineral (BLM) layers rapidly on the exterior surfaces of chitosan (CS) microparticles (MPs). The CS MPs were fabricated using a scale-up double emulsification method. The CS MPs were in the spherical shape and the size of 30–60 μm. The MPs were then placed in 5× concentrated simulated body fluid (5 × SBF) and allowed to undergo biomineralization to form a BLM layers on the surface of CS MPs at 37°C over a 24 h period. The BML layers on the exterior surface of CS MPs were characterized using wide angle X-ray diffraction (XRD), Fourier transform infrared microscopy (FTIR), and scanning electron microscopy (SEM). Insulin like growth factor-1 (IGF-1) was dissolved at a concentration of 1 μg/ml in 5 × SBF to incorporate into the BLM layer. The CS MPs (100 mg) were incubated in a sample of 4 ml of 5 × SBF containing IGF-1 at a concentration of 1 μg/ml for 24 h. The IGF-1 release from BML layers on CS MPs were studied by placing MPs in 4 ml of phosphate buffered saline (PBS) and incubating MPs at 37°C for 30 days. Samples (100 μl) were taken over the course of the 30 days and analyzed using Enzyme-linked Immunosorbent assay (ELISA). The release IGF-1 from BML layers was in a burst manner followed by a sustained release during the 30-day period. This study suggests that the CS MPs have the potential to be used to help deliver therapeutic drugs to localized areas and hence increase and accelerate bone growth.     

The year 2000 problem: how will it affect health care quality improvement? An interview with David Kibbe. Interview by Stephen Berman

A case of a primary yolk sac tumor of the spinal cord is reported. The patient was a 17-month-old Japanese girl, who was found to have an intramedullary mass at the upper thoracic level. The preoperative diagnosis was primary glioma, but histological examination of the surgical specimen revealed a yolk sac tumor. As there were no other lesions, the spinal cord lesion was considered to be the primary tumor. Based on our previous experience, we treated this patient with low-dose irradiation followed by combination chemotherapy with cisplatin, vinblastine and bleomycin. However, the effectiveness of this therapy was poor in this particular case, and the patient died of pyelonephritis with uncontrollable imbalance of serum electrolytes.