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Thirty Japanese clinical isolates of Mycobacterium tuberculosis were analysed by pyrazinamide susceptibility testing and pyrazinamidase assay, as well as polymerase chain reaction for single-strand conformational polymorphism and direct sequencing of the gene encoding pyrazinamidase (pncA). All sensitive isolates showed pyrazinamidase activity and a wild-type pncA gene, but three resistant isolates had pncA gene mutations and lacked pyrazinamidase activity. The latter isolates showed a minimum inhibitory concentration of at least 100 mg/l by the 7H10 agar proportion method and 400 mg/l by the 7H9 liquid medium method. Isolate 28 showed T-to-C change at position 11, leading to Leu4→Ser substitution; isolate 29 had an 8-bp deletion from position 382; and isolate 30 had A-to-C change at position 29, leading to Gln10→Pro substitution. The deletion has not been described previously. This is the first demonstration of pncA gene mutations in PZA-resistant M. tuberculosis strains isolated from Japanese patients.

Vertical nitrate fluxes associated with turbulent mixing and upwelling around a small reef in the Kuroshio are quantified by continuously deploying a turbulence microstructure profiler with an attached submersible ultraviolet nitrate analyzer while drifting from the upstream to the downstream of the reef. Flow separations and trains of Kelvin‐Helmholtz billows (thickness = 60 m) are identified using a shipboard ADCP and an echo‐sounder. The turbulence diffusivity associated with the vigorous turbulent mixing reaches up to O(10−1m2s−1), resulting in strong nitrate fluxes of O(1–103mmol m−2day−1). In addition, large differences between the upstream and downstream density profiles suggest a strong upwelling velocity of O(10−3m s−1), as well as an upwelling nitrate flux of O(102mmol m−2day−1) in the entire subsurface layer. Vertical nitrate fluxes associated with flow‐topography interactions around a small reef in the Kuroshio Current are quantified using state‐of‐the‐art oceanographic instruments. When the flow passes over a shallow sill on the flank of the reef, the velocity differences between layers intensify, resulting in a substantial vertical overturning and mixing of the water column. This turbulent mixing causes the observed nitrate flux from deep water to reach a value among the highest observed worldwide. Flow separations and trains of Kelvin‐Helmholtz billows mix the water column around a small reef in the KuroshioDoming of isopycnals/nitraclines suggests strong upwelling in the lee of the reefTurbulent nitrate fluxes reach up to O(103mmol m−2day−1) Flow separations and trains of Kelvin‐Helmholtz billows mix the water column around a small reef in the Kuroshio Doming of isopycnals/nitraclines suggests strong upwelling in the lee of the reef Turbulent nitrate fluxes reach up to O(103mmol m−2day−1)

A polymerase chain reaction was devised to simultaneously detect repeated insertion sequences and the pertussis toxin promoter gene for the diagnostic identification of Bordetella pertussis, B. parapertussis, and B. bronchiseptica. The sensitivity of this method was sufficient to detect one B. pertussis organism using the following cycles and temperatures: 95°C for 15 min, followed by 32 amplification cycles (1 min at 95°C., 1 min at 66°C., 1 min at 72°C), and finally 5 min at 72°C. Using the primers as a combined set did not affect sensitivity, but required an increased temperature for optimal annealing compared with a single-sequence assay. As nasopharyngeal aspirate and swab materials sometimes contain hemoglobin, we also tested the inhibitory effect of hemoglobin on this assay, which was inhibited completely when using DNA extracts from samples containing hemoglobin at a final concentration < 0.015 g/L: this inhibition was reversed by addition of bovine serum albumin to the buffer. Our assay shows promising sensitivity and specificity for clinical use.

Auditory postauricular response (PAR) was determined in 52 subjects with normal hearing and 83 patients with unilateral peripheral facial nerve palsy. PAR was induced bilaterally by bilateral aural stimulation in 50 (96%) of the 52 subjects. Determination of PAR in the 83 patients disclosed that the prognosis was significantly (p<0.01) better for those in whom PAR occurred within 4 weeks of onset, in comparison with those without PAR. PAR determination was thus considered to be a useful procedure for determining the prognosis of peripheral facial nerve palsy.

It is well known that opioids produce inhibitory effects on neuronal activity and on synaptic transmission at most synapses. In this study, we have investigated the effects of opioids on the low voltage and high voltage activated calcium channels in acutely dissociated submandibular ganglion (SMG) neurons, using the whole-cell configuration of the patch clamp technique. The κ-opioid-receptor agonist U-50488H, the δ-opioid-receptor agonist [D-Pen2,5]- enkephalin and the μ-opioid-receptor agonist [D-Ala2, N-Me-Phe4, Gly5-ol]-enkephalin inhibited L-, N- and P/Q-type calcium-current components in a dosedependent manner at 10nM–1mM, respectively, but not the T-type calcium current. These inhibitory effects were antagonized by naloxone (1mM). The results showed that three types of opioid receptors regulate the L-, N- and P/Q-types of calcium channels, respectively, but not the T-type, in SMG neurones.

A cerebral injury was induced by the bilateral common carotid artery occlusion and recirculation in spontaneously hypertensive rats (SHRs). Employing this ischemia-recirculation rat model, the effects of beraprost sodium (beraprost) on (1) lipid peroxide formation, (2) the increase in the brain water content and (3) neurological signs were examined. In a dosage of 25 µg kg^-1 or higher, beraprost, administered orally, significantly inhibited the formation of lipid peroxides in the brain and serum induced by cerebral ischemia and subsequent recirculation in a dose-dependent manner. Beraprost also alleviated ptosis and markedly inhibited abnormal running behaviour caused by the ischemia and subsequent recirculation. In addition, although administration of beraprost did not cause marked inhibition of the increase in the brain water content (used as an index of cerebral oedema) during the first 3 h after recirculation, it restored the normal brain water content within 24 h after recirculation. Therefore, this effect was observed evidently later than the effect of inhibition of lipid peroxide formation. Moreover, administration of beraprost resulted in improvement in the symptoms accompanying the ischemic treatment. These results suggest that beraprost is potentially useful for prevention or treatment of the pathological state accompanying cerebral infarction. Copyright 1993, 1999 Academic Press

The adsorbed state of NH3 in the vanadium pentaoxide hydrate, V2O5·nH2O, and its chemical reactivity with additionally introduced H2O were studied by gravimetric adsorption measurements, Fourier transform infrared (FT-IR) spectroscopy, mass spectroscopy, and X-ray defraction (XRD) analyses. It was confirmed by FT-IR spectroscopy that NH3 molecules are adsorbed at first to form NH4⁺ by reacting with intrinsically present H2O and secondly as molecular NH3 or IR-inactive NH4⁺. These adsorbed states were also confirmed by mass spectroscopy. When H2O vapor is introduced in the NH3-presorbed sample, NH4VO3 is formed topotactically with its (001) plane parallel to that of V2O5·nH2O. Here, H2O reacts with additional molecular NH3 giving locally the NH3 water between the layers. The NH3 water led to the dissolution of the hydrate and to crystallization of NH4VO3.

Previously, we have reported that aspirin, a cyclooxygenase (COX) inhibitor, can prevent the fibrosis, cirrhosis and generation of oxidative DNA damage, and the associated development of glutathione-S-transferase placental form (GST-P)-positive preneoplastic liver nodules, caused by a choline-deficient, L-amino acid-defined (CDAA) diet in rats. In the present study, in order to elucidate the role of COX pathway in liver lesion-induction by a CDAA diet, the modulatory effects of other distinct chemical classes of COX inhibitors were examined. A long-acting example, piroxicam (PIRO) (at doses of 0.01, 0.02, 0.04 and 0.06%) and the short-acting ibuprofen (IBU) (at doses of 0.02, 0.04 and 0.06%) and indomethacin (IND) (at doses of 0.005 and 0.008%) were administered in the CDAA diet to male F344 rats, and animals were killed after 12 and 30 weeks. In another experiment, IND was given in drinking water at doses of 0.001, 0.002 and 0.004%. None of the inhibitors affected the development of fatty liver caused by a CDAA diet, but PIRO at doses higher than 0.04%, strongly inhibited the development of GST-P-positive and neoplastic nodules as well as fibrosis, cirrhosis and formation of 8-hydroxydeoxyguanosine (8-OHdG) adducts. IBU at the highest dose also exhibited similar but much less pronounced inhibitory effects. With IND, there was only a tendency for inhibition with no clear dose-dependence. The results together with our previous findings, indicate that relatively strong COX inhibitors, acting irreversibly like aspirin or for extended periods like PIRO, can prevent the endogenous hepatocarcinogenesis associated with a CDAA diet, although not the development of a fatty liver, suggesting that an augmented COX pathway might play key roles in the causation of liver lesions in this model.

The effect of 2-methyl-4a alpha-(3-hydroxyphenyl)-1,2,3,4,4a,5,12, 12a alpha-octahydroquinolino [2,3,3,-g]isoquinoline (TAN-67), a selective non-peptide delta opioid receptor agonist, on the morphine-induced place preference was examined in mice. Morphine (1-5 mg/kg, s.c.) produced a dose-related place preference in mice. In contrast, administration of TAN-67 (5-20 mg/kg, s.c.) did not result in a preference for either the drug- or vehicle-associated place. When TAN-67 (5-20 mg/kg, s.c.) was coadministered with morphine (1 mg/kg, s.c.), the morphine-induced place preference was enhanced dose dependently, and this effect of TAN-67 was suppressed by the pretreatment with naltrindole (1 mg/kg, s.c.), a nonselective delta opioid receptor antagonist, 7-benzylidenenaltrexone (0.05 and 0.5 mg/kg, s.c.), a selective delta 1 opioid receptor antagonist, and naltriben (0.05 and 0.5 mg/kg, s.c.), a selective delta 2 opioid receptor antagonist. In biochemical study, morphine (1 mg/kg, s.c.) or TAN-67 (20 mg/kg, s.c.) alone did not modify dopamine turnover in the limbic forebrain. Coadministration of TAN-67 (20 mg/kg, s.c.) with morphine (1 mg/kg, s.c.) increased DA turnover in the limbic forebrain. This increase in DA turnover in the limbic forebrain was suppressed by pretreatment with naltrindole (1 mg/kg, s.c.) or 7-benzylidenenaltrexone (0.5 mg/kg, s.c.), but not by naltriben (0.5 mg/kg, s.c.). Our results demonstrate that coadministration of TAN-67 with morphine enhances the morphine-induced place preference via activation of both delta 1 and delta 2 opioid receptors, suggesting that both delta 1 and delta 2 opioid receptors may modulate the morphine-induced rewarding effect. In addition, we also found that although both delta 1 and delta 2 opioid receptors may be implicated in the modulation of rewarding effect of morphine, the mechanisms involved may be different for each receptor subtypes, i.e., mu-delta 1 interaction may mainly modulate the rewarding effect of morphine by enhancing neurotransmission of mesolimbic dopamine neurons, although modulation by mu-delta 2 opioid receptor interaction may involve some other dopamine-independent mechanisms.

An experiment was performed to investigate whether, during regression of the liver hyperplasia induced by a direct mitogen, apoptosis differentially affects replicated and non-replicated hepatocytes. After a single dose of the direct mitogen lead nitrate (LN), male Wistar rats were given repeated injections of tritiated thymidine, and were killed either 3 days (time of maximal hepatic DNA increase) or 15 days (complete regression of the hyperplasia) after mitogen treatment. Determination of liver DNA radioactivities and labelling indices (LIs) at the two time points revealed an approximately 40% loss in total liver DNA radioactivity, a 20% decrease in the specific activity of DNA, and a 20% reduction in the cell LI. Three days after LN administration 64% of the apoptotic bodies contained thymidine grains in their nuclear fragments. The results indicated that apoptosis affects both hepatocytes that replicated, and those that did not replicate, the former being slightly more sensitive. A second experiment was then performed to investigate whether and to what extent different types of cell death (apoptosis versus necrosis) influence the growth of hepatocytes initiated by a chemical carcinogen. Male Wistar rats were given a single dose of diethylnitrosamine, and 2 weeks thereafter either a single dose of LN, or a necrogenic dose of carbon tetrachloride (CCl4). Bromodeoxyuridine was next infused for 5 days, and some of the animals were killed at this time point, and others after an additional 3 weeks. Administration of CCl4 resulted in an increase in both the average size and the percentage area occupied by placental glutathione S-transferase-positive lesions. In contrast, administration of lead nitrate resulted in a strong reduction (50%) in the number of positive lesions with no remarkable change in the percentage area occupied by them. These differential effects occurred even though comparable LIs were observed in rats treated with the two agents. The results suggest that lead nitrate leads to a loss of initiated hepatocytes, due to the apoptosis that occurs during regression of the LN-induced hyperplasia.

Effects of inhibitors of arachidonic acid (AA) metabolism on the development of fatty liver, cirrhosis, glutathione-S-transferase placental form (GST-P)-positive nodules and the generation of 8-hydroxydeoxyguanosine (8-OHdG) and thiobarbituric acid-reactive substances (TBARS), caused by a choline-deficient, L-amino acid-defined (CDAA) diet, were examined in male Fischer 344 rats by feeding CDAA diets supplemented with the inhibitors for 12 and 30 weeks. Acetylsalicylic acid (ASA) (at doses of 0.1 and 0.2%) and p-bromophenacylbromide (BPB) (0.1 and 0.2%) were used as inhibitors of, respectively, cyclo-oxygenase and phospholipase A2, and quercetin (QU) (0.75 and 1.5%) and nordihydroguaiaretic acid (NDGA) (0.1 and 0.2%) as inhibitors of lipoxygenase. None of the inhibitors affected the development of fatty liver caused by the CDAA diet. ASA at a doe of 0.2% almost completely prevented the appearance of cirrhosis, GST-P-positive nodules, 8-OHdG and TBARS in seven out of 11 (63.7%) rats. BPB at a dose of 0.2% also exerted inhibitory effects on all of these lesions but to a lesser extent than ASA. QU and NDGA exerted inhibitory effects limited to the GST-P-positive nodule case. The results indicate that a perturbed AA metabolism, particularly of the cyclo-oxygenase pathway, derived secondarily from depletion of labile methyl groups or phosphatidylcholine, might play key roles in the cirrhosis, hepatocarcinogenesis and oxidative stress caused by a CDAA diet. The results also indicated a possible involvement of the lipoxygenase pathway in hepatocarcinogenic processes.

Novel gas sensing devices based on a porous platinum (Pt) metal-oxide-semiconductor field-effect transistor (MOSFET) have been fabricated. The catalytic properties of the porous Pt surface for hydrogen (H2) enhance the gas detection sensitivity of the MOSFET gas sensor. The threshold voltage decreases rapidly as time increases when the device is exposed to H2 gas. It was possible to detect 22 ppm of H2 gas with a response time of < 2 min at a device temperature of 27°C. The gas sensitivity could be enhanced to ~10 times higher than that of an unmodified Pt surface.