Thromboxane B2 biosynthesis and phospholipids hydrolysis in platelets from hypercholesterolemic rabbits

Thromboxane B₂ biosynthesis from arachidonic acid was increased in platelets from hypercholesterolemic rabbits. The enzymic activity of phospholipase A₂ which releases arachidonic acid, the precursor for the biosynthesis of thromboxane B₂, showed hardly any change in hypercholesterolemic platelets. Phospholipase C and diglyceride lipase activities also were not changed in platelets from hypercholesterolemic rabbits. Furthermore, phospholipid concentration in platelets were not increased in this state. Thus, we conclude that the supply of precursor for thromboxane B₂ biosynthesis was not increased in platelets from hypercholesterolemic rabbits as compared to controls. These results suggest that the enzyme activity of thromboxane B₂ biosynthesis may be enhanced in platelets from hypercholesterolemic rabbits.     

Technetium-99m tetrofosmin imaging in patients with subacute thyroiditis

We studied the significance of technetium-99m tetrofosmin scintigraphy in patients with subacute thyroiditis (SAT). Six patients with SAT, who had painful goitre with thyrotoxicosis, underwent 99mTc-pertechnetate scintigraphy and 99mTc-tetrofosmin imaging during the acute and recovery stages of SAT. The thyroid uptake ratio of tetrofosmin was compared with the clinical parameters associated with SAT. 99mTc-pertechnetate scintigraphy showed markedly reduced uptake in the thyroid during the acute stage of SAT, suggesting that the appropriate metabolic pathway is not functioning. Conversely, 99mTc-tetrofosmin images showed diffuse increased uptake in the thyroid region on early and delayed imaging. Tetrofosmin images in the acute stage and in the recovery stage of SAT showed different clearance curves for tetrofosmin uptake. The uptake ratio assessed as thyroid uptake/background (T/B) correlated with the serum C-reactive protein concentration. In conclusion, 99mTc-tetrofosmin uptake may reflect the inflammatory process associated with SAT, and thus this tracer may have potential as a marker of disease activity and severity.     

Neuroprotective effect of an antioxidant, ebselen, in patients with delayed neurological deficits after aneurysmal subarachnoid hemorrhage

OBJECTIVE: The effect of ebselen, a seleno-organic compound with antioxidant activity through a glutathione peroxidase-like action, on the outcome of subarachnoid hemorrhage was evaluated in a multicenter placebo-controlled double-blind clinical trial. METHODS: Patients who suffered aneurysmal subarachnoid hemorrhages of Hunt and Kosnik Grades II through IV at admission and were able to start drug treatment within 96 hours of the ictus were enrolled. Early surgery was performed whenever possible. Oral administration of ebselen granules suspended in water (150 mg, twice a day) or placebo was started immediately after admission and continued for 2 weeks. The major end points were the Glasgow Outcome Scale at 2 weeks, 1 month, and 3 months after the start of treatment. The incidence of delayed ischemic neurological deficits clinically diagnosed as resulting from vasospasm and the incidence and extent of low-density areas on postoperative computed tomographic scans were also studied as secondary outcome measures. RESULTS: Intent-to-treat analysis of the 286 patients enrolled in the trial (145 patients administered ebselen and 141 administered placebo) revealed that the incidence of clinically diagnosed delayed ischemic neurological deficits was unaltered. There were 52 (receiving ebselen) and 58 (receiving placebo) patients with delayed deficits; however, a significantly better outcome was observed after ebselen treatment than after placebo (P = 0.005, chi2 test). There was a corresponding decrease in the incidence and extent of low-density areas (P = 0.032, Wilcoxon rank sum test). CONCLUSION: Ebselen reduced brain damage in patients with delayed neurological deficits after subarachnoid hemorrhage and may be a promising neuroprotective agent.     

80 GHz silicon diamond-heatsink Impatt diodes

80 GHz band silicon d.d.r. Impatt diodes with diamond heatsinks were fabricated. An output power of 1014 mW at 77.70 GHz was obtained by liquid-nitrogen-cooled operation, which gives the highest pf2 product, and 726 mW at 73.35 GHz by room temperature operation. Small-signal diode impedance was calculated considering operating temperature.     

Propagation velocity of normal zones in a SC braid

Propagation velocities of normal zones are obtained experimentally in a superconducting (SC) braid which is wound into a coil to simulate the SC pulsed dipole magnet for a synchrotron from the viewpoint of cooling. A numerical calculation to determine this velocity is carried out by using a modified thermal conduction equation. The equation eliminates a troublesome problem on the boundary condition reported previously by defining a new variable of the square of the heat flux along the conductor. A velocity dependent correction factor is used for cooling to take account of the transient effect. The values calculated are a representation of the experimental dependence of the velocity on both current and magnetic field and this indicates that the correction factor is applicable to the winding of the braid if modified properly. Discussion is also made on the transient cooling in the coil.     

The mode of action of immunological adjuvants. II. Generation of a potent precursor of antibody-forming cell by adjuvant

The mode of action of mycobacterial adjuvants was studied in mice, using a 'plaque size' technique and purified adjuvants, wax D and AD6. Data were obtained which suggest that the adjuvants do not act directly on antibody-forming cells or memory cells but on their precursors. The injection of the adjuvants alone apparently caused the generation of competent precursor cells in the spleen as well as in the bone marrow of mice, which developed large plaques and the generation of memory cells developing large plaques upon antigenic stimulation.     

Preparation of multilayered organic-inorganic hybrid core-shell particles by stepwise surface formation

This paper introduces a stepwise formation method for micro-sized, multilayered core-shell particles comprising an inorganic core, organic inner shell, and inorganic outer shell. A silica core was coated with a polystyrene seed layer, followed by surface seed polymerization with styrene, to afford the inner shell. These particles were then coated with a silica outer shell by a surface sol-gel reaction with tetraethoxysilane. The versatility of this combined surface seed polymerization and sol-gel method is emphasized by the precise control achieved over particle diameter as well as shell thickness and count. Moreover, the organic inner shell can be readily eliminated to afford a single-core-containing micro-capsular structure.     

A simple and reproducible testing method for dialkyl phthalate migration from polyvinyl chloride products into saliva simulant

We describe a method of mechanical agitation to determine rates of dialkyl phthalate migration from polyvinyl chloride (PVC) products into saliva simulant. The method consists of rotary shaking of a sample with 30 mL of saliva simulant (pH 7.0) at 35 degrees C in a 50 mL glass tube at 300 rpm for 15 min, then measuring the amount of dialkyl phthalate in the saliva simulant by HPLC with a UV detector. The migration rates of diisononyl phthalate (DINP), di-2-ethylhexyl phthalate (DEHP) and di-n-butyl phthalate (DBP) from PVC plates containing about 45% (w/w) plasticizer (molded in our laboratory) were identical. However, the migration rates from molded plates containing 13% (w/w) DBP were almost double those of DINP and DEHP at the same ratios. In addition, the amounts of DINP that migrated in vitro after rotary shaking for 15 min were equivalent to those in vivo determined in saliva from volunteers who chewed plates for 60 min. The migration rates of dialkyl phthalates from 11 commercially available toys ranged from 15.6 to 85.2 micrograms/cm2/h [relative standard deviation (RSD), 3 to 12%].     

Spectroscopic Measurement of L X-rays Emitted by Transuranium Elements by Using TES Microcalorimeter

Energy spectra of L X-rays emitted by \(^{237}\) Np and uranium isotopes progenies of \(^{241}\) Am and plutonium isotopes were measured by a transition edge sensor (TES) microcalorimeter for demonstration of peak separation with high energy resolution. L X-ray photons emitted by transuranium (TRU) elements can to be utilized for a nondestructive TRU monitor. Major L X-ray peaks are clearly distinguished in the energy spectrum of L X-rays obtained by the simultaneous measurement for radiation sources of \(^{241}\) Am and plutonium isotopes. The value of full width at half maximum energy resolution is 60.21 eV for a peak corresponding to Np L \(_{\beta 1}\) X -rays of 17.751 keV in \(^{241}\) Am source measurement. Comparable energy resolutions were obtained in other experiments. This measurement demonstrated separation of \(^{241}\) Am and plutonium isotopes by L X-ray spectroscopy using TES microcalorimeter.