Use of REMEDi HS in emergency toxicology for a rapid estimate of drug concentrations in urine, serum, and gastric samples

The REMEDi HS is a broad spectrum drug identification system, designed for emergency toxicology screening and forensic applications. The total analysis time is about 20 min. The current library has 555 drugs and metabolites. The system has a software routine that uses an internal standard (IS) to perform quantitative analysis for target compounds when calibrators are available; further, response factors (RF) are supplied for a rapid estimate of drug concentrations when calibrators are unavailable. In the present study, The concentrations of six drugs (bromisovalum, ephedrine, hydroxyzine, diphenhydramine, ranitidine, and lidocaine) and a metabolite of lidocaine (glycinexylidide) were determined using both methods. The slopes of the regression lines between the rapid estimate method and the IS method were generally within 20% of unity, in agreement with the manufacturer's claim. Semiquantitative estimates based on RF also showed good agreement with results obtained using multipoint calibration. These estimates were sufficient for clinical differentiation of routine and toxic levels. Our study demonstrated that the REMEDi HS is particularly useful for a rapid estimate of drug concentrations in the samples from emergency cases when calibrators are not readily available. Our study also showed that this system can be used for the therapeutic monitoring of ranitidine, bromisovalum, lidocaine, and diphenhydrmine.     

Quantitative determination of 1,2-diacylglycerol in thoracic aorta of the rat using latroscan TLC/FID: Effect of norepinephrine

This study was undertaken to evaluate the use of the Iatroscan TLC/FID system for quantitating 1,2-diacylglycerol (DG) in the aorta. Cholesteryl acetate was chosen as an internal standard. In order to avoid interference of triglyceride and phospholipids with the separation of the internal standard and 1,2-DG, a stepwise elution of lipids from the silicic acid column was used. The development of Chromarods was done using two solvent systems and a three-step developing technique. Assay and recovery of both 1,2-DG and cholesterol (as compared to cholesteryl acetate) were sufficient to measure changes in the 1,2-DG content in blood vessels. After exposing the thoracic aorta to 10⁻⁵ M norepinephrine for 10 min, the 1,2-DG content increased nearly two-fold without significant change in cholesterol content.     

Sequential changes of tau-site-specific phosphorylation during development of paired helical filaments

It has been reported that many tau sites in neurofibrillary tangles (NFT) are abnormally phosphorylated. We investigated the phosphorylation of tau in the hippocampus of nondemented patients and Alzheimer's disease patients by immunostaining with five site-specific antibodies against phosphorylated tau. In the pretangle stage, tau in neuropil threads was phosphorylated at serines 199, 202 and 409, numbered according to the longest human tau isoform, whereas tau in some neuronal soma was phosphorylated at serines 199, 202, 409 and 422. Tau at the stage of NFT was phosphorylated at serine 396 and threonine 231 in addition to serines 199, 202, 409 and 422. In the advanced stage, tau in ghost tangles was phosphorylated mainly at serine 396. These results suggest that the phosphorylation of each site in tau differs among the maturing stages of neurofibrillary change and that abnormal phosphorylation of tau in the neuronal soma occurs at 199, 202, 409 and 422 earlier than at threonine 231 and serine 396.     

Tensile and impact properties changes of HASTELLOY X after exposure in high-temperature helium environment

Experimental results are presented on the changes in mechanical properties of HASTELLOY X* after being used in the liner tube of HENDEL hot gas duct under high temperature helium gas for about 6000 hours. In both room and elevated-temperature tensile tests, 0.2 pct proof stress and total elongation were significantly decreased after exposure in high temperature helium. Room-temperature impact toughness of the exposed specimens exhibited a much lower absorbed energy (about 5.0 × 10⁶ J/m²) than that of unexposed specimens (about 1.5 × 10⁶ J/m²). The fracture modes of tensile test specimens were more closely correlated with the test temperature than with the long-time exposure; however, long-time exposure is more affected by the tensile strength of HASTELLOY X than the test temperature. Moreover, “downstream effect” for the carbide precipitation reaction occurred in the liner tube of the HENDEL hot gas duct. HASTELLOY is a trademark of Cabot Corporation.     

Optical logic functions using a tunable wavelength conversion laserdiode

The authors demonstrate optical logic functions of an inverter (NOT) and an exclusive-OR (XOR) using a tunable wavelength conversion (TWC) laser diode developed as a component in optical wavelength division multiplexing (WDM). The TWC laser's optical functions are easily changed by varying bias current settings in gain sections. At just above the turn-on threshold, the TWC laser acts as an optical inverter. At just below the turn-off threshold, it acts as an optical XOR element. The mechanism of both NOT and XOR operations is based on gain quenching accelerated through a saturable absorber, a major feature of the TWC laser. Single longitudinal-mode lasing and the tunability of the lasing wavelength, other features of the TWC laser, are effective in distinguishing lasing light signals from input light signals