Study of the K_{L}→π

The rare decay K_{L}→π^{0}νν[over ¯] was studied with the dataset taken at the J-PARC KOTO experiment in 2016, 2017, and 2018. With a single event sensitivity of (7.20±0.05_{stat}±0.66_{syst})×10^{-10}, three candidate events were observed in the signal region. After unveiling them, contaminations from K^{±} and scattered K_{L} decays were studied, and the total number of background events was estimated to be 1.22±0.26. We conclude that the number of observed events is statistically consistent with the background expectation. For this dataset, we set an upper limit of 4.9×10^{-9} on the branching fraction of K_{L}→π^{0}νν[over ¯] at the 90% confidence level.

Search for K_{L}→π

A search for the rare decay K_{L}→π^{0}νν[over ¯] was performed. With the data collected in 2015, corresponding to 2.2×10^{19} protons on target, a single event sensitivity of (1.30±0.01_{stat}±0.14_{syst})×10^{-9} was achieved and no candidate events were observed. We set an upper limit of 3.0×10^{-9} for the branching fraction of K_{L}→π^{0}νν[over ¯] at the 90% confidence level (C.L.), which improved the previous limit by almost an order of magnitude. An upper limit for K_{L}→π^{0}X^{0} was also set as 2.4×10^{-9} at the 90% C.L., where X^{0} is an invisible boson with a mass of 135 MeV/c^{2}.

Studies on nitrate reductase of Clostridium perfringens. IV. Identification of metals, molybdenum cofactor, and iron-sulfur cluster.

Nitrate reductase of Clostridium perfringens was purified by an improved method using immuno-affinity chromatography. The purified preparation contained Mo, Fe, and acid-labile sulfide; the Mo content was 1 mol per mol and the Fe 3.7 mol per mol of the enzyme. The inactive enzyme obtained from cells grown in the presence of tungstate did not hold Mo but contained 1 mol of W. The content of Fe was not increased. The presence of molybdenum cofactor in the nitrate reductase was indicated by the formation of molybdopterin form A in the oxidation of the enzyme by iodine and by the complementation of NADPH-nitrate reductase with the heart-treated enzyme in the extract of Neurospora crassa nit-1. The Clostridium nitrate reductase had an absorption maximum at 279 nm and shoulders at 320, 380, 430, and 520 nm. This enzyme seems to contain an iron sulfur cluster since the reduced enzyme showed decreased absorption in visible region. The CD spectrum of the enzyme has a positive peak at 425 nm and negative ones at 310, 360, and 595 nm. It was compared with the CD spectrum of ferredoxin (2Fe-2S or 4Fe-4S cluster) and the nitrate reductase of Plectonema boryanum.

Physiological activity of warburganal and its reactivity with sulfhydryl groups.

Warburganal, a unique dialdehyde sesquiterpene isolated from East African Warburgia plants, showed a strong antifungal activity. However, this growth inhibition in Saccharomyces cerevisiae was reversed with L-cysteine. In addition, warburganal inhibited the alcoholic fermentation of S. cerevisiae while L-cysteine reversed this inhibition. When alcohol dehydrogenase, a sulfhydryl enzyme, was incubated with warburganal, the enzyme activity decreased with time. The decrease was more rapid at alkaline pH. L-Cysteine prevented this enzyme inhibition by warburganal but could not restore the enzyme activity lost already due to warburganal. Warburganal lost its characteristic ultraviolet absorption spectrum in the presence of L-cysteine. The change in absorbance was favored at alkaline pH, indicating Michael reaction type addition of L-cysteine to warburganal. Based on these observations, a variety of physiological activities due to warburganal appear to result from its irreversible reactivity with sulfhydryl groups.

Flavonoids in Rosmarinus officinalis leaves.

Three new flavonoid glucuronides, luteolin 3'-O-beta-D-glucuronide, luteolin 3'-O-(4"-O-acetyl)-beta-D-glucuronide, and luteolin 3'-O-(3"-O-acetyl)-beta-D-glucuronide, together with hesperidin, were isolated from 50% aqueous MeOH extract of the leaves of rosemary. The structures were established by chemical and spectroscopic methods. Their antioxidant activities were evaluated by a ferric thiocyanate method with hesperidin showing the greatest activity.

Mode of antibacterial action of retrochalcones from Glycyrrhiza inflata.

Licochalcone A-D and echinatin, retrochalcones isolated from the roots of Glycyrrhiza inflata, showed antimicrobial activity. Among them, licochalcone A and C had potent activity against some Gram-positive bacteria. These retrochalcones inhibited oxygen consumption in susceptible bacterial cells. The oxidation of NADH in bacterial membrane preparations was also inhibited by them. NADH-cytochrome c reductase was inhibited by licochalcones, while cytochrome c oxidase was not. NADH-CoQ reductase and NADH-FMN oxidoreductase were not inhibited. The site of respiratory inhibition of licochalcones was thought to be between CoQ and cytochrome c in the bacterial respiratory electron transport chain.

Molecular design of antibrowning agents.

Tyrosinase inhibitory and antioxidant activity of gallic acid and its series of alkyl chain esters were investigated. All inhibited the oxidation of L-3,4-dihydroxyphenylalanine (L-DOPA) catalyzed by mushroom tyrosinase. However, gallic acid and its short alkyl chain esters were oxidized as substrates yielding the colored oxidation products. In contrast, the long alkyl chain esters inhibited the enzyme activity without being oxidized. This indicates that the carbon chain length is associated with their tyrosinase inhibitory activity, presumably by interacting with the hydrophobic protein pocket in the enzyme. On the other hand, the esters, regardless their carbon chain length, showed potent scavenging activity on the autoxidation of linoleic acid and 1,1-diphenyl-2-p-picryhydrazyl (DPPH) radical, suggesting that the alkyl chain length is not related to the activity. The effects of side-chain length of gallates in relation to their antibrowning activity are studied.

Determination of methylthio and methylsulphone polychlorinated biphenyls in tissues of patients with 'yusho'.

The liver, lung and mesenteric adipose tissue of three patients with 'yusho', polychlorinated biphenyl (PCB) poisoning, and two control persons were analysed for methylthio and methylsulphone metabolites of PCBs by gas chromatography with electron capture detection, gas chromatography-mass spectrometry and mass fragmentography. The tissues were shown to contain two congeners of methylthio PCBs with four chlorine atoms, and 16 congeners of methylsulphone PCBs with three, four, five or six chlorine atoms. The concentrations of methylthio PCBs in the liver, lung and adipose tissue of the yusho patients were 0.1-0.5, 0.2-1.4 and 0.5-1.0 micrograms/kg, respectively, and those of methylsulphone PCBs were 0.3-0.7, 1.0-2.5 and 0.7-1.0 micrograms/kg, respectively. The concentration ratios of methylthio and methylsulphone PCBs to unchanged PCBs were 1-2% in the liver, 4-8% in the lung and 0.1-0.2% in the adipose tissue for yusho patients, indicating that these metabolites accumulate slightly more in the lung and liver than in the adipose tissue, relative to PCBs. The tissue levels of the PCB metabolites in control persons were about one tenth of those in yusho patients.

Single-trial analysis of P3 in patients with generalized epilepsy.

The latencies and amplitudes of averaged P3, and the latencies, amplitudes and frequency components of single EEG responses to target tones were analyzed in 9 control subjects (CS group), 6 epileptics whose mean IQ was 100 (EP group) and 6 epileptics whose mean IQ was 52 (RE group), using an auditory oddball task. All of the subjects responded to the target tones correctly and there were no differences in the incidence of error in response to the target tones, or in the latencies and amplitudes of the averaged P3 among the three groups. However, the reaction times (RTs) in the RE group were significantly longer than those in the other groups (P < 0.05). Single EEG responses to target tone (single-trial ERPs) were classified into 2 types, those with and those without the P3 component. Type 1 had the P3 component and was observed in 42% of all of the responses in the RE group, significantly less than those in the CS (64%) and EP (61%) groups. The peak latencies of P3 in type 1 were similar among the three groups, but the amplitudes of P3 in type 1 in the RE group were significantly greater than those in the CS and EP groups. RTs in the RE group were significantly longer than those in the other groups, and had no correlation with the P3 latencies of type 1. There was little difference in the results of the frequency analysis among the three groups. These results suggest that all subjects in three groups recognized the target tones correctly, but they did not evaluate every target tone, since the incidence of P3 was almost 60% in the CS and EP groups, and 40% in the RE group. The characteristics of cognition and evaluation in three groups were the same, but the decrease in incidence of evaluation and the dissociation between the cognition and the response execution might be caused by impairment of the subject-environment contact mechanism, which resulted in the decrement of IQ in the RE group.

Antiperoxidative activity of neolignans from Magnolia obovata.

Honokiol and magnolol, neolignans in Magnolia obovata, have been evaluated as antioxidants. Microsomal lipid peroxidation induced by Fe(III)-ADP/NADPH and mitochondrial lipid peroxidation induced by Fe(III)-ADP/NADH were inhibited by these compounds. These neolignans protected mitochondrial respiratory chain enzyme activity against NADPH-induced peroxidative stress and protected red cells against oxidative haemolysis. The anti-oxidative activity of honokiol was more potent than that of magnolol. Neolignans in M. obovata were shown to be effective in protecting biological systems and functions against oxidative stress.

Inhibition of lipid peroxidation by sesquiterpenoid in Heterotheca inuloides.

A sesquiterpenoid, 7-hydroxy-3,4-dihydrocadalin, isolated from a Mexican medicinal plant Heterotheca inuloides was evaluated as an antioxidant. This sesquiterpenoid inhibited mitochondrial and microsomal lipid peroxidation induced by Fe(III)-ADP/NADH or Fe(III)-ADP/NADPH. Furthermore, 7-hydroxy-3,4-dihydrocadalin protected red cells against oxidative haemolysis. This sesquiterpene was thus shown to be effective in protecting biological systems against oxidative stresses.

Protection of mitochondrial functions against oxidative stresses by isoflavans from Glycyrrhiza glabra.

Isoflavan derivatives, glabridin (1), hispaglabridin A (2), hispaglabridin B (3), 4'-Omethylglabridin (4) and 3'-hydroxy-4'-O-methylglabridin (5), isolated from Glycyrrhiza glabra, were investigated for their ability to protect liver mitochondria against oxidative stresses. Mitochondrial lipid peroxidation linked to respiratory electron transport and that induced non-enzymatically were inhibited by these isoflavans. Hispaglabridin A (2) strongly inhibited both peroxidations and 3'-hydroxy-4'-O-methylglabridin (5) was the most effective at preventing NADH-dependent peroxidation. 3'-Hydroxy-4'-O-methylglabridin (5) protected mitochondrial respiratory enzyme activities against NADPH-dependent peroxidation injury. Dihydroxyfumarate-induced mitochondrial peroxidation was also prevented by this isoflavan. Isoflavans from G. glabra were shown to be effective in protecting mitochondrial function against oxidative stresses.

The long-term evolutions and the regional characteristics of atmospheric methane concentrations in Nagoya, 1983-1997.

This study provides information on the long-term evolutions of the atmospheric methane (CH4) concentrations in Nagoya City, Japan, which were analyzed by using the continuous monitoring data observed at the eight observatory stations for 1983-1997. The 15-year records of the atmospheric CH4 concentrations were examined by means of a time-series analysis using a fast Fourier transform with a low-pass filter to elucidate the seasonal cycles and the long-term trends. The annual averages of the CH4 concentrations in Nagoya were 1.85 ppmv (parts per million by volume), 1.91 ppmv, and 1.90 ppmv in 1988, 1995 and 1997, respectively. Moreover, the annual average growth rate showed a drastic decrease from 17 ppbv (parts per billion by volume) year(-1) in 1992 to 2 ppbv year(-1) in 1993, and further down to 7 ppbv year(-1) in 1997. Comparison of the atmospheric CH4 records in Nagoya with those in global air of the northern hemisphere observed at Mauna Loa observatory in Hawaii, USA, allows us to estimate the excess concentration of CH4 in the urban atmosphere of Nagoya, which was 0.17 ppmv in 1988 and 0.15 ppmv in 1997. On a local scale, the atmospheric CH4 concentrations in the northern part of Nagoya City increased until 1992 and then gradually decreased from 1993 to 1997, although those in the south-western urban areas constantly increased at the averaged growth rate of 13 ppbv year(-1) for 1988-1997. The variation of the long-term trends of the CH4 concentrations in Nagoya may be ascribed to the emission changes from the CH4 sources due to the human activities such as waste dumping and landfills.

Progressive sensorineural hearing impairment in professional fishery divers.

There have been many reports of a high rate of hearing impairment in divers. A prospective study was performed to determine whether sensorineural hearing acuity in the same divers deteriorated faster than in a normal population as they continued diving. After an observation period of approximately 5 years, audiometric examination was performed on a group of professional fishery divers who had normal hearing or sensorineural hearing loss at the time of initial study. Thirty-three ears of 18 divers were included in statistical analyses. The average hearing deterioration in the divers in 5 years, after elimination of the aging effect, was 6.6 dB (SD 4.5) and was statistically significant. We concluded that the hearing acuity of our subjects deteriorated faster than that of normal Japanese.

Multielement monitoring for dissolved and acid-soluble concentrations of trace metals in surface seawater along the ferry track between Osaka and Okinawa as investigated by ICP-MS.

Multielement monitoring of the concentrations of trace metals dissolved in surface seawater collected at sampling stations along the ferry track between Osaka and Okinawa was performed by ICP-MS (inductively coupled plasma mass spectrometry). The surface seawater samples were collected by an automated sampling system for on-board sampling, which was installed on the bottom of a ferryboat. A part of each seawater sample was filtered with a membrane filter (pore size of 0.45 microm) immediately after sampling. Both filtered and non-filtered seawater samples were acidified to pH ca. 1 by adding conc. HNO3, and were subjected to chelating resin preconcentration for the determination of trace metals by ICP-MS, where the concentrations of analyte metals in the filtered and non-filtered seawater samples were referred to as the dissolved and total concentrations, respectively. According to the thus-obtained results, it was found that most trace metals, especially below the 0.01 microg l(-1) as the dissolved and total concentrations, sensitively reflected the environmental pollution in the Osaka Bay and Seto Inland Sea area, as well as near to the Bungo Canal and the outlet of Kagoshima Bay.

Multielement determination and speciation of major-to-trace elements in black tea leaves by ICP-AES and ICP-MS with the aid of size exclusion chromatography.

A multielement determination of major-to-trace elements in black tea leaves and their tea infusions was carried out by ICP-AES (inductively coupled plasma atomic emission spectrometry) and ICP-MS (inductively coupled plasma mass spectrometry). Tea infusions were prepared as usual tea beverage by brewing black tea leaves in boiling water for 5 min. About 40 elements in tea leaves and tea infusions could be determined over the wide concentration range in 8 orders of magnitude. The extraction efficiency of each element was estimated as the ratio of its concentration in tea infusions to that in tea leaves. From the experimental results for the extraction efficiencies, the elements in black tea leaves were classified into three characteristic groups: (i) highly-extractable elements (>55%): Na, K, Co, Ni, Rb, Cs and Tl, (ii) moderately-extractable elements (20-55%): Mg, Al, P, Mn and Zn, and (iii) poorly-extractable elements (<20%): Ca, Fe, Cu, Sr, Y, Zr, Mo, Sn, Ba and lanthanoid elements. Furthermore, speciation of major-to-trace elements in tea infusions was performed by using a combined system of size exclusion chromatography (SEC) and ICP-MS (or ICP-AES). As a result, many diverse elements were found to be present as complexes associated with large organic molecules in tea infusions.

Pleomorphic adenoma of the external auditory canal: a case report and review of the literature.

Pleomorphic adenoma arising in the external auditory canal is rare. We report the case of a 38-year-old man. To better grasp the clinical features and natural history of this uncommon tumour, we also reviewed the worldwide literature and found 24 similar cases, which we analysed together with our own.

Schwannoma of the posterior pharyngeal wall: a case report.

Schwannoma arising in the posterior pharyngeal wall is rare. We report on a 60-year-old man who complained of discomfort in his pharynx, from whom a tumour was excised via an intraoral approach. No recurrence was seen after an 11-year follow-up. The nerve origin of the tumour is most likely to be the peripharyngeal plexus. This is the third such case reported.

Vestibular schwannoma showing a dural tail on contrast-enhanced magnetic resonance images.

The dural tail on contrast-enhanced magnetic resonance (MR) images, frequently observed in meningiomas, has been used to distinguish between cerebellopontine angle meningiomas and vestibular schwannomas. We report on a 66-year-old female with vestibular schwannoma showing the dural tail on contrast-enhanced MR images. Histological examination revealed that the dural tail corresponded to the thickened dura mater comprising of collagen fibres and scattered hyalinization with no tumoral invasion.

[Clinical experience with aztreonam in the field of obstetrics and gynecology].

Aztreoman (SQ 26,776, AZT), a synthetic monobactam antibiotic, was applied clinically in the field of obstetrics and gynecology. AZT was administered by intravenous drip infusion for 6 to 8 days at a daily dose of 2 g divided in 2 times to 5 cases. Klebsiella in 1 case with puerperal endometritis, Enterococcus, Propionibacterium and Bacteroides in each 1 case with pyometra was isolated. The clinical effect of Klebsiella was excellent. Bacteroides in 1 not-examined case was good. Enterococcus and Bacteroides with pyometra was not effective. Side effects were observed in 2 cases. One case with eclampsia arised LDH and A1-P in serum and 1 case with hepatitis arised GOT and GPT in serum.