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Biomedical subjects

H Watanabe

Publications and source records attributed to H Watanabe.

At least 829 records · Page 46Linked to original sources
PubMed1998

Identification of cpxR as a positive regulator essential for expression of the Shigella sonnei virF gene.

virF is the master regulator which activates the virulence determinant genes of Shigella spp. such as ipaBCD and virG. We previously reported that expression of virF itself is regulated in a pH-dependent manner and that cpxA, a sensor of a two-component regulatory system, is involved in this regulation (S. Nakayama and H. Watanabe, J. Bacteriol. 177:5062-5069, 1995). Disruption of cpxR, which has been thought to be the cognate response regulator of cpxA (J. Dong, S. Iuchi, H.-S. Kwan, Z. Lue, and E. C. C. Lin, Gene 136:227-230, 1993), abolished virF expression almost completely. Purified CpxR bound directly to the upstream region of virF. Binding capacity was enhanced when CpxR was phosphorylated by coincubation with acetyl phosphate in vitro. Furthermore, we observed that phosphorylated CpxR could activate virF transcription in vitro. These results clearly indicated that CpxR was an essential activator for virF expression and strongly suggested that the binding of phosphorylated CpxR to the target site upstream of the virF gene induced a direct activation of virF transcription.

Bacterial Proteins↗
PubMed1998

Epidemiological analysis of Salmonella enteritidis isolates from humans and broiler chickens in Thailand by phage typing and pulsed-field gel electrophoresis.

To determine the phage types (PT) of Salmonella enteritidis found in Thailand and to clarify the potential for human infection by S. enteritidis in broiler chicken meat, human and poultry isolates taken from Thailand between 1990 and 1997 were phage typed and analyzed by pulsed-field gel electrophoresis (PFGE). Ten different PT were found among the 302 isolates phage typed, with PT 4 being the most frequent in human (73.9%) and poultry (76.2%) isolates, followed by PT 1 (8.0%), 8 (3.6%), and 7a (2.2%) in human isolates and by PT 7a (4.9%), 1 (3.7%), and 12 (2.4%) in poultry isolates. Of the 53 isolates analyzed by PFGE, 45 showed an indistinguishable pattern (pattern A) by BlnI-digested PFGE and the other 8 isolates showed a very similar pattern that differed by only a few bands. These results indicate the spread of a genetically identical clone of S. enteritidis in humans and poultry in Thailand.

Animals↗
PubMed1998

Infrequent K-ras codon 12 mutation in serrated adenomas of human colorectum.

BACKGROUND: Serrated adenoma is a new morphological subtype of colorectal adenoma. The lesion provides a distinct morphological route to carcinoma, but the underlying genetic changes have not yet been investigated. AIMS: To determine the frequency of K-ras mutation in serrated adenoma. METHODS: The frequency of K-ras codon 12 point mutation in 20 serrated adenomas, five atypical hyperplastic polyps, and 58 sporadic polypoid adenomas was investigated by nested polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) methods. RESULTS: Although most of the serrated adenomas were large (average size 11.4 mm) and polypoid, K-ras codon 12 point mutation was detected in only one of the 20 (5%), which is a significantly lower frequency than that in sporadic polypoid adenomas (18/60; 30%) (p = 0.017). No mutation was detected in the atypical hyperplastic polyps. Three of 20 (15%) serrated adenomas contained a focus of carcinoma in situ, indicating their malignant potential and the existence of a serrated adenoma-carcinoma sequence, but no mutation was detected in the foci of carcinoma in situ. CONCLUSIONS: K-ras mutation is uncommon in serrated adenomas, indicating a different spectrum of genetic alterations in these lesions from those in typical polypoid sporadic adenomas. This subtype of colorectal adenoma represents a new genetic pathway in the histogenesis of colorectal carcinoma.

Adenoma↗
PubMed1998

In vivo investigation of glutamate-glutamine metabolism in hyperammonemic monkey brain using 13C-magnetic resonance spectroscopy.

To investigate the metabolism of glutamate and glutamine in living monkey brain, a system of in vivo 13C magnetic resonance spectroscopy (MRS) using 1H-decoupled 13C spectroscopy combined with monitoring temperature changes in the brain by MR phase mapping was developed. Serial 13C-NMR spectra of the amino acids glutamate and glutamine were acquired non-invasively over 4 h from anesthetized monkey brain after the intravenous administration of [1-13C]glucose (0.5-1.0 g/kg). In the acute hyperammonemic state induced by the administration of ammonium acetate (77 mg/kg bolus), it was observed that 13C incorporation into glutamine-4 was clearly accelerated, without changes of 13C incorporation into glutamate-4. During hyperammonemia, it was shown directly by [2-13C]glucose administration that the anaplerotic pathway for the TCA cycle was also augmented, contributing to the formation of glutamine in the astroglia.

Acetates↗
PubMed1998

Overnight effects of triazolam on cognitive function: an event-related potentials study.

The effects of triazolam on cognitive function and vigilance on the morning following a nocturnal administration were investigated using event-related potentials (ERP) measurement and a sleep latency test (SLT). We previously reported a significant reducing effect on target N1 amplitude on the morning following triazolam administration, suggesting a residual effect of triazolam. In order to demonstrate, which aspect of cognitive function alteration caused the reducing effect on N1 amplitude, we added the ignore condition for ERP measurement, which enabled us to separate mismatch negativity (MMN) from other subcomponents overlapping N1. As a result, MMN was attenuated and sleep latency was shortened on the morning following triazolam administration. Two possibilities were suggested for the mechanism of MMN attenuation. One is GABAergic activation caused by the residual effect of triazolam per se, and the other is the lowered vigilance level demonstrated in the SLT. Further studies are necessary to determine whether this alteration in physiological bases underlying mismatch detection is specific to triazolam and/or other benzodiazepines or related to nonspecific vigilance level.

Acoustic Stimulation↗
PubMed1998

Autocrine motility factor in pulmonary adenocarcinomas: results of an immunohistochemical study.

Autocrine motility factors (AMF) have been shown to play an important role in tumor cell migration and metastasis. We have detected AMF expression in tissue specimens from 119 patients with pulmonary adenocarcinoma and examined the relationship between AMF expression, clinicopathological factors and prognosis. AMF expression was correlated with lymph node metastasis and stage. The prognosis of AMF-positive patients was poorer than that of AMF-negative patients. The expression of AMF correlated with more tumor aggressiveness and worse prognosis in pulmonary adenocarcinomas.

Adenocarcinoma↗
PubMed1998

Nocturnal enuresis.

OBJECTIVE: To clarify the pathogenesis of nocturnal enuresis. METHODS: Overnight simultaneous monitoring of electroencephalogram and cystometrogram, developed in 1985, was the basic method. RESULTS: Nocturnal enuresis was classified into types I, IIa and IIb. In type I, activation of the arousal center functioned correctly, but the development of the function to switch light sleep to complete awakening was immature. In type IIa, activation of the arousal center failed. In type IIb, transmission of the urinary sensation to the upper centrum was ineffective because of the disturbance of bladder function. CONCLUSION: There is a possibility that a universal concept embracing the various theories for enuresis proposed in the past could be obtained from this theory.

Animals↗
PubMed1998

Classification based on overnight simultaneous monitoring by electroencephalography and cystometry.

OBJECTIVES: To evaluate the features of the clinical findings in three types (types I, IIa, IIb) of enuresis, classified by overnight simultaneous monitoring by electroencephalography (EEG) and cystometry (CM). METHODS: We performed a test to evaluate bladder capacity, arousal response and the pattern of nighttime urination in sucklings and infants. RESULTS: As for the values of enuretic bladder capacity (EBC), the smallest were found in enuresis type IIb. As for arousal response, enuresis type I showed the best, while enuresis type IIa showed the worst response. With regard to the pattern of nighttime urination in sucklings and infants, all sucklings had a stable bladder in the sleep state and urinated in the pattern of type IIa. The arousal response to bladder distention indicating type I appeared at the age of about 2 or 3. CONCLUSIONS: The smallest EBC in patients with enuresis type IIb represented a bladder dysfunction in the sleep period. It was observed that patients with enuresis type I had the best arousal function while those with enuresis type IIa had the worst arousal function. All sucklings urinated unconsciously during sleep in the pattern of type IIa. The arousal response to bladder distention indicating type I, which was not observed below the age of 1 year, was thought to appear at the age of about 2 or 3 years. If this change has not appeared by the age of 3, bed-wetting might persist after the age of 5.

Child, Preschool↗
PubMed1998

Effects of systematic treatment based on overnight simultaneous monitoring of electroencephalography and cystometry.

OBJECTIVE: To clarify the effects of systematic treatment based on overnight simultaneous monitoring by electroencephalography (EEG) and cystometry (CM) on each type of enuresis. METHODS: For enuresis type I, the change in the awakening response during the conditioning treatment with a therapeutic machine was observed. For enuresis type IIa, the effect of imipramine on the EEG was observed. For enuresis type IIb, the effect of oxybutynin hydrochloride on the cystometrogram (CMG) was observed. RESULTS: Values, in which the awakening score on the second night was subtracted from the score on the last night, were significantly higher in the effective cases than in the unchanged cases. Out of the 3 patients in whom imipramine was effective, an awakening response on the EEG was observed in 2. Neither of the 2 unchanged cases showed an awakening response. Out of 4 patients in whom oxybutynin hydrochloride was effective, uninhibited contractions (UIC) on the CMG disappeared in 3. UIC stopped in neither of the 2 unchanged cases. CONCLUSIONS: Improvement of the awakening response plays an important role in the effectiveness of conditioning treatment with our therapeutic machine. The generation of awakening response is thought to be the most important result of imipramine directly concerned with its clinical effect on enuresis type IIa. The main result with oxybutynin hydrochloride in enuresis type IIb is thought to be related to its antispasmodic effect.

Adrenergic Uptake Inhibitors↗
PubMed1998

Comparison between Er:YAG laser and conventional technique for root caries treatment in vitro.

Effective ablation of dental hard tissues by means of the erbium-doped:yttrium-aluminum garnet (Er:YAG) laser has been reported recently, and its application to caries removal and cavity preparation has been expected. However, few studies have investigated the capability of the Er:YAG laser to treat caries. In the present study, the effectiveness of caries removal by using an Er:YAG laser in vitro was compared with that of conventional mechanical treatment. Thirty-one extracted human teeth with root caries were used. Half of the caries in each tooth was treated with the Er:YAG laser, and the other was removed with a conventional bur or was left untreated as a control. Laser treatment was performed by means of a combination of contact and non-contact irradiation modes with cooling water spray, with a new fiber delivery and contact probe system. Conventional bur treatment was conducted by means of a low-speed micromotor. Measurements of the time required for caries removal, histopathological observations of decalcified serial sections, scanning electron microscope (SEM) observations, and hardness measurements of the treated cavity-floor dentin were performed for each treatment. Due to the careful irradiation technique, a longer treatment time was required for the complete removal of carious dentin by the Er:YAG laser. However, the Er:YAG laser ablated carious dentin effectively with minimal thermal damage to the surrounding intact dentin, and removed infected and softened carious dentin to the same degree as the bur treatment. In addition, a lower degree of vibration was noted with the Er:YAG laser treatment. The SEM examination revealed characteristic micro-irregularities of the lased dentin surface. Our results show that the Er:YAG laser system is promising as a new technical modality for caries treatment.

Dental Cavity Preparation↗
PubMed1998

Role of daunorubicin in the induction therapy for adult acute myeloid leukemia.

PURPOSE: To evaluate the relationship of total-dose of daunorubicin (DNR) to the induction therapy and treatment outcome, we have administered individualized doses of DNR during induction treatment to patients with acute myelogenous leukemia (AML). PATIENTS AND METHODS: Ninety-two previously untreated adult patients with AML who entered our hospital were analyzed for the dose of DNR required to achieve complete remission (CR), the CR rate, disease-free survival (DFS), and overall survival (OS). Induction therapy consisted of DNR 40 mg/m2 daily intravenously from day 1 until the marrow was hypoplastic, cytarabine (Ara-C), prednisolone (PRD), and/or 6-thioguanine (6-TG). RESULTS: Eighty-three of 92 patients with adult AML were assessable for this study. Sixty-three (76%) patients achieved CR. Fifty-two of 63 CR patients achieved the CR in the first course of induction therapy, and 11 patients required the second course of induction therapy. The 5-year and 10-year DFS rates were 31.2% and 5-year and 10-year OS rates were 45.1% and 42.3%, respectively. The median total dose of DNR in the induction therapy was 280 mg/m2 (120 to 480 mg/m2). DNR dose did not influence the response to therapy and was not influenced by the initial WBC count or French-American-British (FAB) system classification. CONCLUSION: These results indicated that when the dose was linked to observed tumor response, the optimal dose of DNR in the induction therapy was approximately 280 mg/m2 (40 mg/m2 for 7 days), which is greater than the conventional dose of 40 to 60 mg/m2 for 3 days.

Adolescent↗
PubMed1998

Actin mRNA isoforms are differentially sorted in normal osteoblasts and sorting is altered in osteoblasts from a skeletal mutation in the rat.

Actin isoform sorting has been shown to occur in a variety of cell types in culture. To this list we add osteoblasts, in which we show by in situ hybridization that beta-actin is distributed primarily in cell processes and on one side of the nucleus and gamma-actin has a perinuclear distribution. Osteoblasts from the skeletal mutation toothless (tl), evaluated under identical conditions, fail to sort these actin isoforms differentially and exhibit diffuse labeling as their major manifestation. Northern analyses of actin mRNAs showed no differences between normal and mutant cultures. Shortened osteoblast life span and an inability to direct osteoclast-mediated bone resorption have recently been demonstrated in tl mutants. The present results suggest that a failure of osteoblasts to sort actin mRNAs may be related to one or both of these pathological manifestations in this mutation and represent, to our knowledge, the first correlation of an actin mRNA-sorting abnormality with a mammalian disease.

Actins↗
PubMed1998

Analysis of the sinusoidal endothelial cell organization during the developmental stage of the fetal rat liver using a sinusoidal endothelial cell specific antibody, SE-1.

The sinusoid organization during the development of fetal rat livers was studied using a SE-1 antibody, which we have previously established as a specific monoclonal antibody against rat sinusoidal endothelial cell (SEC). Expression and localization of the SE-1 antigen in the liver tissues of 13- to 21-day-old fetuses were immunofluorescently and immunoelectron microscopically examined. The first positive fluorescence was observed in the immature liver of 15-day-old fetuses. The initial positive staining was randomly distributed in the liver parenchyma and showed no direct relation to the large vessels which may be derived from the fetal vitelline veins. The positive linear staining increased in number and connected with each other during the course of development. The SE-1 staining pattern and the sinusoidal arrangement became similar to those of the adult liver after 20th day of gestation. Immunoelectron microscopically, the immature SEC showed a weak positive reaction for the SE-1 antigen at their membrane and was observed together with immature hepatocytes and hematopoietic cells in the 15-day-old fetal liver. Along with the liver development, SEC formed a sinusoid structure closely associated with hepatocytes and came to strongly express the SE-1 antigen. These results indicate that the organization of the hepatic sinusoid may start at around 15th day of the gestation and occurs randomly in the fetal liver parenchyma. It is also suggested that the expression of SE-1 antigen is possibly regulated by the intimate association with hepatocytes.

Animals↗
PubMed1998

Effects of paeoniflorin derivatives on scopolamine-induced amnesia using a passive avoidance task in mice; structure-activity relationship.

Paeoniflorin (1) and its derivatives having in common a cage-like pinane skeleton with hemiketal-acetal system, were evaluated for their effects on memory impairment induced by scopolamine in mice using a step-down type passive avoidance task. In the test session, 1 and its derivatives were intraperitoneally (i.p.) administered at doses of 0.002, 0.01, 0.02 and 0.2 mmol/kg, and 30 min later (15 min before the experiment), scopolamine (1 mg/kg, i.p.) was given. These compounds showed dose-dependent attenuation in a dose range of 0.002-0.02 mmol/kg and also enhancement of scopolamine-induced decrease in step-down latency. The effects of these compounds, except that of 2',3',4',5'-O-tetraacetyl-3-O-methylpaeoniflorin (8), followed a bell-shaped dose response profile. 8-Debenzoyl-6-deglucosyl-3-O-methylpaeoniflorin (6) showed no significant increase in the step-down latency at all tested doses. Maximum step-down latency was obtained by 3-O-methylpaeoniflorin (3) and 2',3,3',4',5'-penta-O-methylpaeoniflorin (7) (the minimal effective dose was 0.002 mmol/kg). Relative to 3, debenzoylation, as in 8-debenzoyl-3-O-methylpaeoniflorin (4), slightly increased the latency, while deglucosylation, as in 6-deglucosyl-3-O-methylpaeoniflorin (5), significantly reduced the prolongation of latency. Removal of both glucose and benzoyl moieties resulted in the loss of activity as seen in 6. These results revealed that, in addition to the cage-like pinane skeleton, the benzoyl and the glucosyl moieties are important structural elements of the paeoniflorin skeleton as its effects on scopolamine-induced amnesia.

Amnesia↗
PubMed1998

An alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) antagonist and an N-methyl-D-aspartate (NMDA) channel blocker synergistically impair spatial memory in rats.

The interaction of the alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) antagonist YM90K with the competitive N-methyl-D-aspartate (NMDA) antagonist CGS19755 or with the NMDA channel blocker MK801 on the spatial memory of rats was examined by the 4-arm-baited radial maze task. When administered alone, these drugs had no effect on the spatial memory. The combination of YM90K and MK801 synergistically disrupted working and reference memories, whereas the combination of YM90K and CGS19755 had no effect. These results indicate that the blockade of the AMPA receptor and NMDA channels produces a synergistic impairment of spatial memory and suggest that interaction between the AMPA and NMDA receptors plays a role in cognitive function.

Animals↗
PubMed1998

In vitro antioxidant activity of Vietnamese ginseng saponin and its components.

To elucidate the antioxidant action of Vietnamese ginseng saponin against free radial-mediated cellular damage, we examined the effect of Vietnamese ginseng saponin on lipid peroxidation in the mouse brain, liver, and liver microsomes by using two in vitro free radical generating systems (iron ferrous+ascorbic acid and iron ferrous+hydrogen peroxide). Free radical-mediated lipid peroxidation was determined by measuring the endogenous and stimulated accumulation of thiobarbituric acid reactive substance (TBA-RS). Vietnamese ginseng saponin (0.05-0.5 mg/ml), as well as vitamin E, significantly inhibited the formation of TBA-RS in tissue homogenates. Panax ginseng saponin, at the same concentration range as Vietnamese ginseng saponin, also had inhibitory action on free radical-mediated lipid peroxidation. However, majonoside-R2, ginsenoside-Rg1 and ginsenoside-Rb1, the main saponin components of Vietnamese ginseng saponin fraction, had no effect on lipid peroxidation. These results suggest that Vietnamese ginseng exerts a protective action against free radical-induced tissue injury and that this effect is attributable to minor components rather than the main saponin components tested.

Animals↗
PubMed1998

Potent anticonvulsant paeonimetabolin-I derivatives obtained by incubation of paeoniflorin and thiol compounds with Lactobacillus brevis.

Seventeen thiopaeonimetabolin-I adducts were obtained as mixtures of diastereoisomers after incubation of paeoniflorin with Lactobacillus brevis in the presence of various thiols. Four compounds, 8-(n-hexylthio)- (8), 8-cyclopentylthio-, 8-(p-tolyl)thio- and 8-benzoylthio- (18) paeonimetabolins, showed 100% protection against pentylenetetrazole-induced convulsions at doses of 0.125, 0.25, or 0.50 mmol/kg, relative to valproic acid (100% protection at 1.5 mmol/kg). For 8 and 18, the principle anticonvulsant activity resided in the (7S)-isomers while (7R)-isomers showed muscle relaxation effects.

Animals↗