Liquid crystal thermography; a reliable method for detecting soda lime exhaustion

The dynamic and functional state of soda lime can be more precisely assessed by measuring changes in wall temperatures of the absorption chambers rather than observing color change of the soda lime granules. We demonstrated in this report that the liquid crystal thermometer is an inexpensive and reliable measuring device for this purpose.     

Radioprotective effects of thiomethylhydantoin derivatives on Escherichia coli and mice

Protection of Escherichia coli NIHJ and C57BL mice from the effects of 60Co gamma-rays provided by S-alk(en)yl-L-cysteines and their hydantoin derivatives was examined. E. coli (10(6) cells/ml) suspended in a 20 mM aqueous solution of one of the drugs was irradiated with 60 Gy of gamma-rays. Five week-old male mice were exposed to 5.0-9.5 Gy of gamma-rays after a single intraperitoneal injection of 0.75 mmol/kg body weight of each compound. In both E. coli and mice, S-allyl compounds afforded more effective radioprotection than S-propyl compounds. The replacement of the alpha-hydrogen of S-substituted cysteines by methyl groups decreased the radioprotective effect. Hydantoin derivatives were much more radioprotective than the original sulfur-containing amino acids. Especially, DL-5-allylthiomethyl-5-methylhydantoin had a remarkable radioprotective effect in mice. The gamma-radiolysis mechanism of thiomethylhydantoin derivatives was discussed in connection with the radioprotective effect of the drugs.     

Existence of phenol oxidase in the argasid tick Ornithodoros moubata

Phenol oxidase (PO, EC 1.10.3.1) activity was detected in the hemolymph of the fourth instar nymphs of the argasid tick, Ornithodoros moubata, with peak levels corresponding to the days before the majority of the nymphs had molted, suggestive of a protective role of PO during the ecdysial phase. Higher PO activity was detected in plasma relative to the hemolymph and was negligible in hemocytes. The concentration of the hemolymph and plasma assayed clearly influenced the level of PO activity, and was significantly reduced ( P<0.005) after treatment with 1-phenyl-2 thiourea, a specific PO inhibitor. This is the first report of the existence of PO in the hemolymph and plasma of a soft tick species. The regulation of PO activity and its precise role in soft tick immunity, particularly during the ecdysial phase, are interesting and need to be examined further.     

Forced expression of terminal deoxynucleotidyl transferase in fetal thymus resulted in a decrease in gammadelta T cells and random dissemination of Vgamma3Vdelta1 T cells in skin of newborn but not adult mice

The repertoire of lymphocyte receptor genes encoded in a germline is further diversified by a number of processes, including the template-independent addition of nucleotides (N regions) by means of terminal deoxynucleotidyl transferase (TdT). Normally, mouse gammadelta T cells in the early fetal thymus, whose T-cell receptor (TCR) genes lack N regions and are encoded by Vgamma3-Jgamma1 and Vdelta1-Ddelta2-Jdelta2 with canonical junctions (invariant Vgamma3Vdelta1), are thought to be the precursors of dendritic epidermal T cells (DETC). We generated mutant mice whose endogenous TdT promoter was replaced with the lck promoter through homologous recombination. These mutant mice expressed TdT in fetal thymus, had abundant N regions and infrequent canonical junctions in gamma and delta rearrangements, and showed a decreased number of gammadelta T cells. Various Vgamma3Vdelta1 T cells, most of which had N regions in their TCR genes, were found to disseminate in the skin of newborn mutant mice, whereas normal numbers of DETCs with the invariant Vgamma3Vdelta1 rearrangement were observed in adult mutants. These data demonstrate that the regulation of TdT expression during fetal development is important for the generation of gammadelta T cells, and that Vgamma3Vdelta1 T cells, which have various junctional sequences in their TCR genes, randomly disseminate in skin, but invariant Vgamma3Vdelta1 T cells have a great advantage for proliferation in skin.     

Anesthetic induction agents, sympathetic nerve activity and baroreflex sensitivity: a study in rabbits comparing thiopental, propofol and etomidate

The mechanisms of arterial hypotension following intravenous anesthetic induction agents are multifactorial. The purpose of this study was to evaluate and compare the effects of thiopental, propofol and etomidate on hemodynamics, sympathetic outflow and arterial baroreflex sensitivity using not only neuraxis-intact but also totally baro-denervated rabbits. A total of 60 rabbits was anesthetized with urethane, tracheotomized, and mechanically ventilated with oxygen in nitrogen (FiO2 0.5). The left renal sympathetic nerve was isolated and placed on a bipolar electrode to record renal sympathetic nerve activity (RSNA). Thirty animals underwent a surgical preparation of total baroreceptor denervation. Bolus injections of an anesthesia induction dose of thiopental 4 mg/kg and twice the induction dose of propofol 4 mg/kg significantly decreased RSNA to the same extent (19.4+/-6.7 and 19.7+/-5.2% reduction, mean +/- SEM) and mean arterial pressure (MAP) also to the same extent (19.5+/-4.6 and 22.1+/-3.1% reduction) in the neuraxis-intact animals. RSNA was increased (34.5+/-6%) without reduction of MAP by an induction dose of etomidate, 0.3 mg/kg. Sympathetic barosensitivity was attenuated even 10 min after thiopental at 4 mg/kg or propofol at 4 mg/kg (68% and 54% of control, respectively). Propofol at 2 mg/kg (induction dose) and etomidate at 0.6 mg/kg decreased RSNA and MAP only in the baro-denervated animals. It was found from the barosensitivity study that patients can be hemodynamically unstable even though blood pressure has returned to normal after thiopental and propofol administration. Data suggest that etomidate can even stimulate the sympathetic nervous system and increase sympathetic outflow. It was also clearly found from the baro-denervated animal study that thiopental was stronger than propofol in directly suppressing sympathetic outflow at the induction dose.     

The effects of CaEDTA injection on lead,zinc, copper and ALAD in erythrocyte,plasma and urine in lead-exposed workers: a 24-h observation

Summary To evaluate the effects of calcium disodium ethylenediamine tetraacetate (CaEDTA) on the concentrations of lead, zinc and copper in plasma, erythrocyte and urine, and the delta-aminolevulinic acid dehydratase (ALAD) activity in erytrocyte, we administered CaEDTA in 1-h intravenous infusion to ten male gun metal founders with blood-lead concentration of 39 to 64 g/dl (mean 49 g/dl). We found that the plasma concentration of lead, following a rapid rise within the first 3 h, fell temporarily to the level significantly lower than the initial level 19 h after start of the infusion. The plasma concentration of zinc fell to the minimal level 5 h after the infusion; and the erythrocyte concentration of zinc and the ALAD activity concurrently rose to the maximal level 5 h after the infusion. By contrast, no significant alteration was observed in the concentrations of copper in plasma and erythrocyte. The maximal level of urinary metal excretion was attained during the period between 1 and 2 h after start of CaEDTA infusion for lead; within 2 h for zinc; and between 2 and 4 h for copper. The urinary metal excretion returned to the initial level 14 to 24 h after infusion for zinc and copper; but lead excretion was still higher than the initial level during this period. The difference in the kinetics of the three metals following CaEDTA injection is discussed in the light of these findings.     

Study on the developing potentiality of mouse morula produced in vitro or in vivo after vitrification

Great horovement haS been made in the cryopreservation Of inalnlnalian elnbmp since wnttingham['] reported his Pioneering wold about successful cryOPreservationof mouse embryo. It results in the availability of cryOPreserVation of embryos of all stages[']. HOwever, cryopreserved embryos can not avoid the damages by ice crystal,which is a major cause of cen death in the freezing andthawing ProceduresL',']. SO it is necesseq to seareh for anew and more efficient method for embryO cryOPrese…     

Contribution of peripheral chemoreception to the depression of the hypoxic ventilatory response during halothane anesthesia in cats

BACKGROUND: The effects of inhalational anesthetics on the hypoxic ventilatory response are complex. This study was designed to determine the contribution of peripheral chemoreception to the depression of hypoxic ventilatory response seen with halothane anesthesia. METHODS: Cats were anesthetized with pentobarbital sodium and alpha-chloralose and artificially ventilated. Respiratory output was evaluated by phasic inspiratory activity of the phrenic nerve. In 12 cats, this activity was measured during inhalation of an hypoxic gas mixture with halothane, 0, 0.1, and 0.8%, with intact or denervated carotid bodies. In 10 cats, a carotid body was isolated from the systemic circulation and perfused with hypoxic Krebs-Ringer solution equilibrated with halothane, 0, 0.1, and 0.8%. RESULTS: The hypoxic ventilatory response was depressed in a dose-dependent manner during halothane anesthesia. In carotid body perfusion studies, the response was significantly depressed only with halothane, 0.80%. CONCLUSION: The hypoxic ventilatory response is depressed by a high dose of halothane through a peripheral effect at the carotid body.