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Biomedical subjects

Y Asano

Publications and source records attributed to Y Asano.

At least 397 records · Page 22Linked to original sources
PubMed1995

Cloning, nucleotide sequencing, and expression of an opine dehydrogenase gene from Arthrobacter sp. strain 1C.

The gene coding for opine dehydrogenase from Arthrobacter sp. strain 1C was cloned onto plasmid pBluescript KS(-), and the nucleotide sequence of the 1,077-bp open reading frame consisting of 359 codons was identified as the odh gene. Transformed Escherichia coli cells overproduced NAD+-dependent opine dehydrogenase under control of the promoter of the lac gene on pBluescript KS(-).

Agrobacterium tumefaciens↗
PubMed1995

Specific increase in interleukin-8 concentrations in dialysis fluid of patients with peritonitis receiving continuous ambulatory peritoneal dialysis.

AIMS: To evaluate the influence of interleukin-8 (IL-8) and other inflammatory cytokines (IL-6, IL-1 beta and tumour necrosis factor alpha (TNF alpha)) on the occurrence of peritonitis in patients receiving continuous ambulatory peritoneal dialysis (CAPD). METHODS: The study population comprised 12 patients with peritonitis, 33 without peritonitis, all undergoing CAPD, and five patients undergoing peritoneal catheter implantation. Cytokine concentrations in dialysis fluid were determined by immunoassay and their values compared. RESULTS: Concentrations of both IL-8 (median 147 pg/ml, range 20-2273 pg/ml; n = 12) and IL-6 (median 1120 pg/ml, range 96-10,600 pg/ml) were substantially elevated, while the IL-1 beta concentration was lower and TNF alpha was not detectable in patients at diagnosis. The IL-6 concentration was also elevated in patients undergoing catheter implantation as well as in those with peritonitis. The IL-8 concentration, however, was elevated only upon infection. Intraperitoneal production of IL-8 was evident on determination of paired serum and dialysis fluid cytokine concentrations, and immunostaining of peritoneal cells with monoclonal anti-IL-8 antibody. CONCLUSIONS: These results suggest that determination of the IL-8 concentration in dialysis fluid maybe useful as a specific marker for following patients with peritonitis receiving CAPD.

Adult↗
PubMed1995

Potassium secretion is inhibited by metabolic acidosis in rabbit cortical collecting ducts in vitro.

The role of metabolic acidosis in the regulation of transepithelial potassium transport was examined in rabbit cortical collecting ducts (CCD) using in vitro isolated tubular microperfusion and conventional microelectrode techniques. Basolateral metabolic acidosis, created by reduction of bicarbonate concentration from 25 to 5 meq/l, pH 7.40 to 6.80, depolarized the transepithelial voltage significantly (-6.5 +/- 1.0 to -2.7 +/- 1.3 mV). Basolateral acidosis also suppressed net potassium secretion (-14.3 +/- 2.1 to -9.0 +/- 1.7 pmol.min-1.mm-1). Electrophysiological study in CCD cells demonstrated that basolateral metabolic acidosis depolarized transepithelial voltage and apical and basolateral membrane voltage with an increase of transepithelial and fractional apical resistance. Basolateral acidosis did not affect the 22Na efflux nor 86Rb efflux. The inhibitory action of basolateral acidosis on net potassium secretion remained in the presence of luminal barium and in the absence of bicarbonate. Ouabain could not abolish the effect of basolateral acidosis on transepithelial voltage completely. These data lead us to conclude that basolateral acidosis affects multiple transport pathways, and it inhibits mainly apical barium-sensitive potassium transport. Additionally, it inhibits apical sodium conductance, barium-insensitive potassium transport, and stimulates a ouabain-insensitive electrogenic transport pathway to some degree.

Acidosis↗
PubMed1995

Activation of protein kinase C stimulates cAMP phosphodiesterase in rat renal collecting tubule.

The present study was undertaken to evaluate whether protein kinase C (PKC) affects adenosine 3',5'-cyclic monophosphate phosphodiesterase (cAMP-PDIE) activity in microdissected rat renal medullary collecting tubules (MCT). Phorbol 12-myristate 13-acetate (PMA, 10(-8) M), an activator of PKC, significantly stimulated cAMP-PDIE activity in intact MCT (29.5 +/- 1.5 to 38.3 +/- 3.7 fmol.min-1.mm-1, P < 0.05) but not in the proximal straight tubule [4.7 +/- 0.8 vs. 4.8 +/- 0.8, not significant (NS)] or the medullary ascending limb of Henle's loop (20.5 +/- 2.1 vs. 22.4 +/- 2.8, NS). PMA-stimulated cAMP-PDIE activity was reversed by PKC inhibitors, staurosporine (10(-8) M) and calphostin C (10(-8) M), but not by the cyclooxygenase inhibitor, indomethacin (5 x 10(-6) M). 1,2-Dioctanoyl-sn-glycerol (50 micrograms/ml), a synthetic analogue of diacylglycerol that stimulates PKC, also increased cAMP-PDIE activity in broken-cell preparations from MCT. This stimulation was also suppressed by staurosporine (10(-8) M) and calphostin C (10(-8) M). The stimulatory effect of PMA on cAMP-PDIE activity was lost with rolipram (10(-4) M), a type IV PDIE inhibitor, whereas it was preserved with N-(6-amino-hexyl)-5-chloro-1-naphthalenesulfonamide hydrochloride (W-7) (10(-4) M), a calmodulin inhibitor, or vinpocetin (10(-4) M), a direct inhibitor of type I PDIE. From these results, we suggest that activation of PKC specifically stimulates rolipram-sensitive cAMP-PDIE, but not the calmodulin-sensitive isozyme, in rat MCT.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1995

Luminal prostaglandin E2 modulates sodium and water transport in rabbit cortical collecting ducts.

We have previously found that arginine vasopressin (AVP) acts not only from the basolateral side but also from the luminal side of the rabbit cortical collecting duct (CCD). In the present study, we examined whether prostaglandin E2 (PGE2), another classic and potent modulator of the collecting duct functions, exerts luminal actions in the rabbit CCD perfused in vitro. Although luminal prostaglandin I2 was inert, luminal PGE2 (> 1 nM) induced transient hyperpolarization of transepithelial voltage followed by sustained depolarization in a dose-dependent manner. This action was preserved in the presence of basolateral PGE2, luminal AVP, or luminal BaCl2, but abolished by basolateral ouabain or luminal amiloride. Furthermore, unlike luminal AVP, luminal PGE2 suppressed Na transport and increased osmotic water permeability. The present study suggests that PGE2, similar to AVP but in a different fashion, modulates transepithelial transports from both luminal and basolateral sites in the CCD in vivo.

Animals↗
PubMed1995

Urinary excretion of thiobarbituric acid reactive substances of healthy subjects supplemented with a high dose of d-alpha-tocopherol.

The level of urinary thiobarbituric acid reactive substances (TBARS) consisting of bound forms of malonaldehyde and, to a lesser extent, other aldehydes is one of the indices of lipid peroxidation status. Levels of urinary TBARS in healthy subjects before and after supplementation with a high dose of d-alpha-tocopherol were measured using high performance liquid chromatography. Four healthy Japanese were given a supplement of 300 mg d-alpha-tocopherol/d, about 40-fold higher than the normal intake recommended, for a period of 50 d. Levels of urinary TBARS (nmol/kg body weight.h) within-day, before and after supplementation with d-alpha-tocopherol, exhibited similar behavior and levels of daily urinary TBARS (nmol/kg body weight.d) were unchanged by d-alpha-tocopherol supplementation. These results indicate that supplementation with a high dose of d-alpha-tocopherol does not affect the level of urinary TBARS.

Female↗
PubMed1995

Nucleotide sequencing of phenylalanine dehydrogenase gene from Bacillus badius IAM 11059.

The nucleotide sequence of the pdh gene coding for PheDH from Bacillus badius IAM 11059 was analyzed. The gene consists of an ORF of 1140 nucleotides which specifies a protein of 380 codons. The primary structure of PheDH is similar to PheDH from B. sphaericus, PheDH from Themoactinomyces intermedius, and leucine dehydrogenase from B. stearothemophilus, etc.

Amino Acid Oxidoreductases↗
PubMed1995

Purification and properties of crystalline 3-methylaspartase from two facultative anaerobes, Citrobacter sp. strain YG-0504 and Morganella morganii strain YG-0601.

3-Methylaspartase (3-methylaspartate ammonia-lyase, EC 4.3.1.2) from two facultative anaerobes from soil, Citrobacter sp. strain YG-0504 and Morganella morganii strain YG-0601, were purified and crystallized from their crude extracts. Both of the Citrobacter and Morganella enzymes appeared to be a dimer of subunits of M(r) 40,000 and 44,000, respectively. The enzymes had similar enzymological properties: optimum pH for the deamination reaction of (2S,3S)-3-methylaspartic acid, substrate specificity, inhibitor, divalent and monovalent cation requirement, and N-terminal amino acid sequence homology. However, some differences were detected in pH and temperature stability, optimum pH for the amination reaction of mesaconic acid, optimum temperature, specific activity, and stability during electrophoresis. Both enzymes had similar enzymological properties to the known 3-methylaspartase from an obligate anaerobic bacterium, Clostridium tetanomorphum H1, except kinetic constants and substrate specificities.

Amino Acid Sequence↗
PubMed1995

Clinical features and viral excretion in an infant with primary human herpesvirus 7 infection.

OBJECTIVE: To find clinical features of a virologically-confirmed patient with primary human herpesvirus 7 (HHV-7) infection and a relationship of the excretion of viruses between HHV-7 and human herpes-virus 6 (HHV-6). PATIENT AND METHODS: A 13-month-old boy who had a known prior history of exanthem subitum at 6 months of age developed fever for 3 days and a skin rash appeared as the fever was resolving. The course was accompanying with nonspecific signs and symptoms such as anorexia, irritability, mild diarrhea, palpebral edema, mild inflammation of pharynx, and mild occipital and cervical lymphadenopathy. Heparinized blood samples were used for isolation of HHV-6 and HHV-7 and detection of both virus DNA sequences by a nested polymerase chain reaction (PCR) amplification. Samples from other body sites were also tested for their DNA sequences using the PCR. Both virus antibody activity was measured by an indirect immunofluorescent assay or a neutralization test. RESULTS: Cultured mononuclear cells from the patient at the acute stage of the disease produced morphologic changes, which reacted only with the monoclonal antibody to HHV-7 but not with the antibody to HHV-6. Both viruses were not isolated from blood obtained at the convalescent stage. An antibody response of the patient indicated a seroconversion to HHV-7 but not to other microbial agents including HHV-6 and Mycoplasma pneumoniae. Both virus DNA sequences were detected in peripheral blood mononuclear cells at acute and convalescent stages. HHV-7 DNA was excreted into saliva and transiently into stool at an early convalescent stage followed by HHV-6 excretion into saliva. No HHV-7 and HHV-6 was excreted into urine. CONCLUSIONS: Clinical features of a virologically confirmed patient with primary HHV-7 infection were comparable with those of primary HHV-6 infection and HHV-7 infection may reactivate HHV-6.

Antibodies, Viral↗
PubMed1994

Crystalline 3-methylaspartase from a facultative anaerobe, Escherichia coli strain YG1002.

Crystalline 3-methylaspartase (EC 4.3.1.2) from Escherichia coli strain YG1002 that had been isolated from soil was characterized. The enzyme activity was induced when the organism was grown statically on medium containing (S)-glutamic acid. Its molecular mass is about 84 kDa, and it may be composed of two identical subunits of 42 kDa. The enzyme requires both divalent and monovalent cations such as Mg2+ and K+, respectively. The enzyme catalyzes reversible amination-deamination between mesaconic acid and (2S,3S)-methylaspartic acid, which is the best substrate.

Ammonia-Lyases↗
PubMed1994

Investigation of varicella-zoster virus DNA by the polymerase chain reaction in healthy children with varicella vaccination.

Investigation of varicella-zoster virus (VZV) DNA in 20 healthy children with varicella vaccination was carried out by using the polymerase chain reaction (PCR) and nested double PCR. Samples of peripheral blood mononuclear cells (PBMC) and throat swabs were simultaneously collected 3 times (before, 1 week, and 4 weeks after vaccination) for PCR analysis. One sample of PBMC was also obtained from each of the 12 healthy children with varicella during the acute phase as a positive control. VZV DNA was not found by the first PCR in any samples except one PBMC of a control subject. The nested double PCR, which is a more sensitive method for VZV DNA detection, was applied to the same samples. The viral DNA was detected in every PBMC of the controls, and in 2 (16.7%) PBMC at 1 week and in 6 (50%) PBMC at 4 weeks after vaccination in the 12 vaccinees with seroconversion. In 3 of 4 vaccinees who were seropositive before vaccination, VZV DNA was detected in PBMC at 1 or 4 weeks after vaccination. The three vaccinees showed a booster immunization with a significant increase in antibody titers. In contrast, no VZV DNA could be detected in any throat swabs of all the vaccinees nor in PBMC of the vaccinees who did not seroconvert.

Ambulatory Care Facilities↗
PubMed1994

Detection of varicella-zoster virus DNA in blood of children with varicella.

The nested polymerase chain reaction was used to detect varicella zoster virus (VZV) DNA in 67 samples of peripheral blood mononuclear cells (PBMC) from 39 otherwise healthy children with varicella. Eleven were during the incubation period and 56 were after appearance of rash. VZV DNA was detected in two of eight (25%) PBMC at the early phase of the incubation period (day -14 to -11). The rate of the detection increased to 67% in -5 to -1 days prior to the onset of the rash and 46% in 0-4 days after the onset. It declined gradually with time and was undetectable in patients after 15 days from the clinical onset. The serum antibody determined with the fluorescent antibody to membrane antigen was first detected in the samples on day 2 and subsequently increased to 100% rapidly. In conclusion, VZV DNA cannot be detected usually in PBMC of healthy children except in varicella.

Antibodies, Viral↗
PubMed1994

Preexisting neurogenic voiding dysfunction in children with imperforate anus: problems in management.

We evaluated 22 boys and 2 girls 1 month to 8 years old with imperforate anus to determine the relationship between neurogenic voiding dysfunction and bony sacral or spinal cord anomalies. Lower urinary tract function before anorectoplasty was normal in 12 children (group 1), abnormal (detrusor-sphincter dyssynergia) in 9 (group 2) and not evaluated in 3 (group 3). High lesions of imperforate anus were present in 22% of the patients in group 1 and in 100% of those in group 2. Plain radiography revealed partial sacral agenesis in 1 child in group 1 and 4 in group 2. Magnetic resonance imaging detected occult spinal dysraphism in 1 patient in group 1 and 2 in group 2. (Occult spinal dysraphism included sacral lipoma, tethered cord, syringomyelia and thick filum terminale.) Seven children in group 2 had vesicoureteral reflux before anorectoplasty. All children in group 2 were placed on clean intermittent catheterization for the management of neurogenic voiding dysfunction. Normal upper urinary tract function was maintained in all patients in group 1 and 6 in group 2. The remaining 3 children in group 2 had high grade reflux at presentation associated with severe renal damage or noncompliance with clean intermittent catheterization. These findings indicate that in children with imperforate anus lower urinary tract function should be evaluated before anorectoplasty because of the high incidence of associated congenital neurogenic voiding dysfunction and the potential risk for renal deterioration. When possible, neurogenic voiding dysfunction should be managed with clean intermittent catheterization to prevent renal damage.

Anus, Imperforate↗