Rat strain minimally influences anesthetic and convulsant requirements of inhaled compounds in rats

We assessed the effect of rat strain on susceptibility to anesthesia and convulsions produced by inhaled compounds. We determined the minimum alveolar anesthetic concentration (MAC) of desflurane and nitrous oxide, and the convulsive 50% effective dose (ED50) of 1,2-dichlorohexafluorocyclobutane, flurothyl, and difluoromethyl-1-chlorotetrafluoroethyl ether in five strains (three inbred [Long Evans, Sprague-Dawley, and Wistar] and two outbred [Fischer and Brown Norway]). Strain had slight effects on anesthetic potency, the strains with the highest MAC values (Long Evans and Brown Norway) having values < or =28% greater than the strains with the lowest values (Sprague Dawley and Wistar). MAC for nitrous oxide correlated directly with MAC for desflurane as a function of strain. MAC for either desflurane or nitrous oxide correlated inversely with the convulsive ED50 of 1,2-dichlorohexafluorocyclobutane, but correlated poorly (and directly) with the convulsive ED50 of the remaining compounds. Convulsivity varied little as a function of strain (greatest difference 21%) and did not vary consistently as a function of strain. No consistent difference was seen between inbred versus outbred strains. IMPLICATIONS: Rat strain has a minimal effect on the potency of inhaled anesthetics or the convulsant activity of inhaled compounds. It seems that the sites acted on by inhaled compounds to produce anesthesia and convulsions are conserved across common rat strains.     

800 V 4H-SiC RESURF-type lateral JFETs

This letter proposes to show that a lateral switching device has some unique advantages, including little dependence on substrate defects, low on-resistance, and a simple design of heat radiation. A reduced surface field (RESURF) type SiC-JFET is one of candidate devices for an electric or hybrid automobile application. Small RESURF-type SiC-JFETs with gate width of 200 /spl mu/m and a blocking voltage of 800 V were fabricated. The fabrication and characteristics of the devices are described and discussed.     

New insights from spectroscopy into the structure/function relationships of lipoxygenases

Spectroscopic properties of the redox-active iron in the active site of plant and mammalian lipoxygenases can now be combined with recent crystal structure determinations to obtain new insights into lipoxygenase reaction mechanisms.     

Drug metabolism biosensors: electrochemical reactivities of cytochrome P450cam immobilised in synthetic vesicular systems

Biosensors containing cytochrome P450cam in a didodecyldimethylammonium bromide vesicular system were prepared by cross-linking onto a glassy carbon electrode (GCE) with glutaraldehyde in the presence of bovine serum albumin. Cyclic voltammetric responses of the sensor in air-free buffer solution showed that the sensor exhibited reversible electrochemistry due to direct electron exchange between the haem Fe(3+/2+) redox system and the GCE surface. In air-saturated solution containing camphor, the biosensor gave an irreversible electrocatalytic current which is compatible with the monooxygenation of the substrate. Steady state amperometric experiments with camphor, adamantanone and fenchone were performed with a biosensor prepared by cross-linking P450cam with glutaraldehyde onto a Pt disc electrode. The sensor was characterised by fast amperometric responses, attaining steady-state in about 20 s in a cobalt sepulchrate mediated electrochemical system. The kinetic parameters of the biosensor were analysed using the electrochemical Michaelis Menten equation. The estimated apparent Michaelis-Menten constant, Km, values for the biosensors were in the range of 1.41-3.9 mM.     

Flexible pulse waveform generation using silica-waveguide-based spectrum synthesis circuit

Pulse waveform shaping with a silica-waveguide-based circuit employing an arrayed-waveguide grating pair and an array of amplitude and phase controllers is demonstrated. The frequency components of a modelocked laser have been flexibly synthesised to produce 40 GHz square pulses with various widths.     

Subcellular distribution of GLUT4 in Chinese hamster ovary cells overexpressing mutant dynamin: evidence that dynamin is a regulatory GTPase in GLUT4 endocytosis

Previous studies have suggested that the neurotrophins brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT-3) are neuroprotective or neurotrophic for certain subpopulations of hippocampal neurons following various brain insults. In the present study, the expression of BDNF and NT-3 mRNAs in rat hippocampus was examined after traumatic brain injury. Following lateral fluid percussion (FP) brain injury of moderate severity (2.0-2.1 atm) or sham injury, the hippocampi from adult rats were processed for the in situ hybridization localization of BDNF and NT-3 mRNAs using 35S-labeled cRNA probes at post-injury survival times of 1, 3, 6, 24 and 72 h. Unilateral FP injury markedly increased hybridization for BDNF mRNA in the dentate gyrus bilaterally which peaked at 3 h and remained above control levels for up to 72 h post-injury. A moderate increase in BDNF mRNA expression was also observed bilaterally in the CA3 region of the hippocampus at 1, 3, and 6 h after FP injury, but expression declined to control levels by 24 h. Conversely, NT-3 mRNA was significantly decreased in the dentate gyrus following FP injury at the 6 and 24 h survival times. These results demonstrate that FP brain injury differentially modulates expression of BDNF and NT-3 mRNAs in the hippocampus, and suggest that neurotrophin plasticity is a functional response of hippocampal neurons to brain trauma.     

Lupus erythematosus-like features in patients with cutaneous T-cell lymphoma

The purpose of this clinical study was to review experience in the management, and outcome of eclamptic patients at Rajavithi Hospital. Standardized treatment for all cases of eclampsia has consisted of magnesium sulfate intravenously and intramuscularly to control convulsions by means of Chesley and Tepper's regimen, intravenous hydralazine intermittently to lower diastolic blood pressure when it exceeds 110 mmHg, and initiation of delivery as soon as the patient has regained consciousness and is stable. During a ten-year period there were 167,200 deliveries and 90 eclamptic patients, yielding an incidence of eclampsia of 1 in 1,857 deliveries. There were three maternal deaths (3.3%) due to intracerebral hemorrhage. Serious adverse maternal outcomes were more frequent in women whose convulsions occurred before delivery. Excluding postpartum cases, perinatal mortality of fetuses weighing 1,000 g or more was 11.7 per cent. Magnesium sulfate is the drug of choice for treatment of eclamptic convulsions. In most situations, clinical assessment of deep tendon reflexes, respirations, and urine output is adequate to monitor maternal magnesium toxicity without the need to determine actual maternal serum magnesium levels.     

Chemical interaction between granular B4C and 304L-type stainless steel materials used in BWRs in Japan

Chemical reactions between stainless steel and boron carbide were investigated using the materials applied for control rods in BWRs in Japan, specifically 304L-type stainless steel and granular boron carbide. The reaction region consisted of 2–4 layers, in which the significant composition variation of each element was detected, especially for B and C. Assuming that the reaction layer growth obeys the parabolic law, the effective rate constant between 304L-type stainless steel and granular boron carbide was evaluated to be approximately one order of magnitude smaller than the previously reported values for boron carbide pellets or powers. This difference might originate from the loose contact between the stainless steel and the granular boron carbide in the present study. Regarding liquefaction progress, the stainless steel components were selectively dissolved in the melt; consequently, the unreacted boron carbide tended to remain.