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Biomedical subjects

Y Morikawa

Publications and source records attributed to Y Morikawa.

At least 91 records · Page 5Linked to original sources
PubMed1998

The gene encoding dipeptidyl aminopeptidase BI from Pseudomonas sp. WO24: cloning, sequencing and expression in Escherichia coli.

We have isolated the dipeptidyl aminopeptidase BI (DAP BI) gene from the plasmid library of Pseudomonas sp. WO24 chromosomal DNA by the enzymatic plate assay using a chromogenic substrate. The DAP BI gene, designated dap b1, was further subcloned and sequenced. Sequence analysis of an approx. 3-kb fragment revealed an open reading frame of 2169 nucleotides, which was assigned to the dap b1 gene by N-terminal and internal amino acid sequences. The predicted amino acid sequence of DAP BI containing a serine protease Gly-X-Ser-X-Gly consensus motif displays extensive homologies to the several proteases belonging to the prolyl oligopeptidase family, a novel serine protease family possessing the catalytic triad with a specific array of Ser, Asp and His in this order, which is the hallmark of the member of this family including DAP IV. The dap b1 gene was expressed in Escherichia coli and the expressed enzyme was purified about 230-fold with 2.6% recovery from the cell-free extracts. The enzymatic properties such as molecular mass, substrate specificity and effect of inhibitor were similar to the native enzyme from Pseudomonas sp. WO24.

Amino Acid Sequence↗
PubMed1998

Effects of maternal uninephrectomy on the development of fetal rat kidney: numerical and volumetric changes of the glomerulus and formation of the anionic site in the glomerular basement membrane.

Developmental processes of the fetal rat kidney from uninephrectomized mothers were studied. The uninephrectomy was performed on day 5 of gestation. Glomerular number and volume in the fetal kidneys on days 18, 20, and 22 of gestation were morphometrically determined. To investigate the anionic site formation in the glomerular basement membrane, distribution of cationized ferritin (CF) in the fetal glomerulus was examined electron microscopically after CF injection. Blood urea nitrogen (BUN) concentration in the pregnant rats was also determined on various days after uninephrectomy. On fetal days 20 and 22, the glomerular volume was significantly larger in the fetuses from uninephrectomized mothers than in those from sham-operated ones. On fetal day 20, the CF particles were clustered in the laminae rarae interna and externa of the glomerular basement membrane in the fetuses from uninephrectomized mothers, while the clusters were arrayed in three to four layers in the glomerular basement membrane in the fetuses from sham-operated ones. On fetal day 22, the CF particles noted in the lamina rara externa in the fetuses from uninephrectomized mothers were slightly larger in number than such particles in the age-matched control fetuses. The BUN concentration of the uninephrectomized pregnant rats was significantly higher than that of the sham-operated pregnant ones on each postoperative day. These results suggest that the development of the fetal renal glomerulus is accelerated by the elevated BUN level following maternal uninephrectomy when the fetal kidney is functional in effective filtration in the rat.

Animals↗
PubMed1998

A de novo missense mutation (R1623Q) of the SCN5A gene in a Japanese girl with sporadic long QT sydrome. Mutations in brief no. 140. Online.

Two missense mutations and a nine-nucleotide deletion of the cardiac sodium channel (SCN5A) gene have been shown to cause long QT syndrome (LQTS) in several familial cases. We identified a novel missense mutation (R1623Q) of the SCN5A gene in a Japanese girl with sporadic LQTS. We used polymerase chain reaction, single-strand conformation polymorphism analysis and DNA sequence analysis to identify a mutation of the SCN5A gene in the patient. A single nucleotide substitution of guanine to adenine, in codon 1612, changed the coding sense of the SCN5A from arginine to glutamine (R1623Q) in the S4 segment of domain IV which is a highly conserved region of the SCN5A. This mutation was not identified in the unaffected biological parents and brother of the patient, and 100 normal, unrelated individuals. This finding is the first evidence of a de nova mutation in SCN5A associated with LQTS.

Amino Acid Substitution↗
PubMed1998

The molecular basis of HIV capsid assembly.

In common with many aspects of the HIV life cycle, the assembly of the virus particle has been the subject of intense investigation over recent years. Study of the subject is facilitated by the fact that only a single gene product, the Pr55 Gag protein, is required for virus assembly. A combination of site directed mutagenesis, biochemical characterisation and structural studies have led to a picture of the overall architecture of the particle, the partial structure of Pr55, and the subdomains involved in oligomerisation. Copyright 1998 John Wiley & Sons, Ltd.

Journal Article↗
PubMed1998

Efficient secretion of Trichoderma reesei cellobiohydrolase II in Schizosaccharomyces pombe and characterization of its products.

A cbh2 cDNA encoding Trichoderma reesei QM9414 cellobiohydrolase II, located on the expression vector whose copy number is controlled by the level of gentamicin, was successfully expressed under the control of a human cytomegalovirus promoter in the fission yeast. Schizosaccharomyces pombe. The 24-amino-acid leader peptide of the cbh2 gene was recognized by the yeast, enabling the efficient secretion of the heterologous cellobiohydrolase. The transformed S. pombe strain produced over 115 micrograms cellobiohydrolase proteins/ml rich medium supplemented with malt extract and 100 micrograms/ml gentamicin. The molecular masses of the recombinant cellobiohydrolases, secreted as two molecular species, were estimated to be 70 kDa and 72 kDa by sodium dodecyl sulfate/polyacrylamide gel electrophoresis (SDS-PAGE). Deglycosylation treatments revealed that the recombinant enzymes were overglycosylated and scarcely susceptible to alpha-mannosidase. The recombinant enzymes showed no carboxymethylcellulase activity, but showed similar characteristics to those of a native enzyme purified from T. reesei in their optimum pH and temperature, pH and temperature stabilities, and Vmax values toward phosphoric-acid-swollen cellulose as substrate, except that their Km values were about four-fold higher than that of the native enzyme.

Cellulase↗
PubMed1998

Extra-anal mucosectomy: laparascopic-assisted endorectal pull-through using a prolapsing technique.

BACKGROUND/PURPOSE: The mucosectomy of the aganglionic rectal mucosa has been performed transabdominally in the Soave procedure. Recently, mucosectomy with transanal approach was reported both in the laparoscopic and the open surgical procedure. However, the operative view and working field are restricted because the dissection has to be done in the anal canal. The authors report an innovative approach, an extra-anal mucosectomy, to perform mucosectomy in the Soave procedure for Hirschspung's disease in combination with the laparoscopic-assisted prolapsing technique. METHODS: Four patients underwent laparoscopic surgery for Hirschsprung's disease with extra-anal mucosectomy between 1995 and 1997. One 10-mm and 5-mm ports were used throughout the operation. The rectum was pulled out through the anal canal to create a rectal prolapse and was divided outside the anal canal. The mucosectomy was performed in the everted rectal mucosa outside the anal canal to the level of dentate line. The colon was sutured to the anal mucosa 2 mm above the dentate line. Mean operative time was 3 hours. RESULTS: The present technique made the whole mucosectomy possible under direct observation. CONCLUSION: The extra-anal mucosectomy in conjunction with a laparoscopic-assisted prolapsing technique seems to be a safe and reliable modality in the surgical treatment of Hirschsprung's disease.

Anal Canal↗
PubMed1998

Molecular characterization and heterologous expression of the gene encoding a low-molecular-mass endoglucanase from Trichoderma reesei QM9414.

We have isolated the genomic and cDNA clones encoding EG III (a low-molecular-mass endo-beta-1,4-glucanase) gene from Trichoderma reesei QM9414. The nucleotide sequence of the cDNA fragment was verified to contain a 702-bp open reading frame that encodes a 234-amino-acid propeptide. The deduced protein sequence has significant homologies with family H endo-beta-1,4-glucanases. The 16-amino-acid N-terminal sequence was shown to function as a leader peptide for possible secretion. Northern blot analysis showed that the EG III gene transcript, with a length of about 700 bp, was expressed markedly by cellulose but not by glucose. The protein has been expressed as a mature form in Escherichia coli and as secreted forms in Saccharomyces cerevisiae and Schizosaccharomyces pombe under the control of tac, alcohol dehydrogenase (ADH1), and human cytomegalovirus promoters, respectively. The S. cerevisiae and Schizosaccharomyces pombe recombinant strains showed strong cellulolytic activities on agar plates containing carboxymethyl cellulose. The E. coli strain expressed small amounts of EG III in an active form and large amounts of EG III in an inactive form. The molecular masses of the recombinant EG IIIs were estimated to be 25, 28, and 29 kDa for E. coli, S. cerevisiae, and Schizosaccharomyces pombe, respectively, by immunoblot analysis following sodium dodecyl sulfate-polyacryl-amide gel electrophoresis. Parts of the yeast recombinant EG IIIs decreased their molecular masses to 25 kDa after treatment with endoglycosidase H and alpha-mannosidase, suggesting that they are N glycosylated at least partly.

Amino Acid Sequence↗
PubMed1998

Purification and Characterization of Exo-beta-d-Glucosaminidase from a Cellulolytic Fungus, Trichoderma reesei PC-3-7.

Chitosan-degrading activities induced by glucosamine (GlcN) or N-acetylglucosamine (GlcNAc) were found in a culture filtrate of Trichoderma reesei PC-3-7. One of the chitosan-degrading enzymes was purified to homogeneity by precipitation with ammonium sulfate followed by anion-exchange and hydrophobic-interaction chromatographies. The enzyme was monomeric, and its molecular mass was 93 kDa. The optimum pH and temperature of the enzyme were 4.0 and 50 degrees C, respectively. The activity was stable in the pH range 6.0 to 9.0 and at a temperature below 50 degrees C. Reaction product analysis from the viscosimetric assay and thin-layer chromatography and H nuclear magnetic resonance spectroscopy clearly indicated that the enzyme was an exo-type chitosanase, exo-beta-d-glucosaminidase, that releases GlcN from the nonreducing end of the chitosan chain. H nuclear magnetic resonance spectroscopy also showed that the exo-beta-d-glucosaminidase produced a beta-form of GlcN, demonstrating that the enzyme is a retaining glycanase. Time-dependent liberation of the reducing sugar from partially acetylated chitosan with exo-beta-d-glucosaminidase and the partially purified exo-beta-d-N-acetylglucosaminidase from T. reesei PC-3-7 suggested that the exo-beta-d-glucosaminidase cleaves the glycosidic link of either GlcN-beta(1-->4)-GlcN or GlcN-beta(1-->4)-GlcNAc.

Journal Article↗
PubMed1998

Detection of a trimeric human immunodeficiency virus type 1 Gag intermediate is dependent on sequences in the matrix protein, p17.

Previous studies have shown that single amino acid changes in the amino-terminal matrix (MA) domain, p17, of the human immunodeficiency virus type 1 Gag precursor Pr55, can abrogate virion particle assembly. In the three-dimensional structure of MA such mutations lie in a single helix spanning residues 54 to 68, suggesting a key role for this helix in the assembly process. The fundamental nature of this involvement, however, remains poorly understood. In the present study, the essential features of the MA helix required for virus assembly have been investigated through the analysis of a further 15 site-directed mutants. With previous mutants that failed to assemble, residues mapped as critical for assembly were all located on the hydrophobic face of the helix and had a key role in stabilizing the trimeric interface. This implies a role for the MA trimer in virus assembly. We support this interpretation by showing that purified MA is trimeric in solution and that mutations that prevent virus assembly also prevent trimerization. Trimerization in solution was also a property of a larger MA-capsid (CA) Gag molecule, while under the same conditions CA only was a monomer. These data suggest that Gag trimerization driven by the MA domain is an intermediate stage in normal virion assembly and that it relies, in turn, on an MA conformation dependent on the hydrophobic core of the molecule.

Animals↗
PubMed1998

Effects of ginkgo biloba extract on impairment of learning induced by cerebral ischemia in mice.

The effect of Ginkgo biloba extract (GbE) on cerebral ischemia induced by 10-min bilateral occlusion of the carotid arteries in mice was studied. Severe impairment of memory was apparent when the passive avoidance test was carried out 48 hr after bilaterally induced ischemia. When GbE at doses of 50 and 100 mg/kg was given p.o. 1 hr before the 10-min occlusion, there was a significant improvement in memory. The i.p. injection of ifenprodil (30 mg/kg) also showed improvement on learning tasks. The p.o. administration of flavonoid, a fraction isolated from GbE, showed high step-through latency on scopolamine-induced amnesia. All these findings indicate that GbE is beneficial for clinical use in amnesia accompanied with cerebral vascular disease.

Amnesia↗
PubMed1998

Biochemical characterization of recombinant HIV-1 reverse transcriptase (rRT) as a glycyrrhizin-binding protein and the CK-II-mediated stimulation of rRT activity potently inhibited by glycyrrhetinic acid derivative.

By means of successive Mono Q and glycyrrhizin (GL)-affinity column chromatography (HPLC), recombinant HIV-1 RT (rRT) was purified to apparent homogeneity from the Superdex 200 pg fraction of the crude protein extract of E. coli BL21 transfected with pET 21a(+)/HIV-1 PR-RT. It was found that (i) rRT functioned as an effective phosphate acceptor for recombinant human casein kinase II (rhCK-II) in vitro; (ii) this phosphorylation was inhibited by anti-HIV-1 substances [a glycyrrhetinic acid derivative (oGA) and quercetin] and a high dose (100 microM) of GL; (iii) RNA-dependent DNA polymerase (RDDP) activity was stimulated about 2.5-fold after full phosphorylation of rRT by rhCK-II; and (iv) oGA as well as NCS-chromophore effectively prevented the CK-II-mediated stimulation of RDDP activity. These results suggest that the anti-HIV-1 effect of oGA may be involved in the selective inhibition of the CK-II-mediated stimulation of HIV-1 RT at the cellular level.

Anti-HIV Agents↗
PubMed1998

[The development of the Japanese version of the Maslach Burnout Inventory and the examination of the factor structure].

This article presents an evaluation of the factor structures of the Japanese version of the Maslach Burnout Inventory (MBI). The MBI is a widely used psychometric instrument for measuring 'burnout' developed by Maslach and her co-workers. The MBI consists of four subscales: Emotional Exhaustion, Personal Accomplishment, Depersonalization, and Involvement. The MBI was translated into Japanese along with a back-translation and was administered to a sample of 267 nurses. Various psychometric analyses showed that the Japanese version of the MBI has high reliability for the 22 items scored for the frequency dimension. The factor analysis using principal factoring with an oblique rotation resulted in three factor structures that had different implications from the MBI: Emotional Exhaustion/Depersonalization, Personal Accomplishment, and Physical Exhaustion. The correlationship between the MBI and the General Health Questionnaire (GHQ), measures of depression, showed that burnout was a unique phenomenon.

Adult↗
PubMed1998

Time course analysis of the reverse-Stroop effect in Japanese Kanji.

A reverse of the Stroop effect was obtained with Japanese kanji (logographic script) but not with Japanese kana (syllabic scripts) by Morikawa in 1981. In the present study, the normal effect on reaction times by word and color was altered by presenting the words before or after the color. The reverse Stroop effect was observed with kanji but not with kana even when the color was presented prior to the word. It was shown that the difference between kanji and kana in the reverse-Stroop effect could not be explained by the relative speed of processing of word and color and that the reading process of kanji is different from that of kana.

Adult↗
PubMed1998

[Fulminant Mycoplasma pneumoniae pneumonia resulting in respiratory failure and a prolonged pulmonary lesion].

A previously healthy 26-year-old woman presented with a fever and coughing on October 1, 1995. Despite treatment with beta-lactam antibiotics at another hospital, she had a high fever, coughing, and dyspnea. A chest roentgenogram showed diffuse infiltrates in both lung fields. On October 9, she was transferred to our hospital. On admission, a chest X-ray film showed marked diffusely infiltrates in both lung fields and a effusion in the left lung. Arterial blood gas analysis after inhalation of 4 liters per minute of oxygen via a nasal cannula revealed a PaO2 of 39.0 torr. Despite treatment with various antibiotics, including minocyclin and gamma-globulin, her respiratory condition rapidly deteriorated. She was mechanically ventilated by with intermittent mandatory ventilation and positive end-experiatory pressure, and received antibiotics and methylprednisolone pulse therapy. He chest X-ray and arterial blood gase findings, gradually improved. The passive hemagglutination titer for Mycoplasma rose from 1:4 on October 9, to 1:2,560 on the 14th hospital day. Acute respiratory failure due to Mycoplasma pneumoniae pneumonia was diagnosed. A chest X-ray film obtained 2 months after admission showed linear-reticular shadows in both lung fields and pulmonary-function tests revealed abnormally low vital capacity and diffusing capacity. Examination of a specimen obtained by transbronchial lung biopsy revealed focal intraalveolar exudate with fibrin and macrophages. Very mild interstitial thickening was also noted. The lymphocyte stimulation responses to PPD, PHA, and Con A were low early in the illness and became normal after recovery. Several reports have said that an enhanced pulmonary cellular immune response may be responsible for the development of severe Mycoplasma pneumoniae, resulting in a temporary decrease in the cell-mediated immune response. This case supports that hypothesis. We believe that in severe cases, steroid therapy including pulse therapy should be started as soon as possible.

Acute Disease↗
PubMed1998

Intrauterine growth acceleration in the case of a severe form of mucopolysaccharidosis type VII.

We describe a Japanese male infant with mucopoly-saccharidosis type VII (MPS VII) who was born at 32 weeks of gestation presenting as a non-immune hydrops fetalis. His birth weight was 2900 g (+4.1 SD), his birth length was 48 cm (+2.2 SD), and thoracic spine length was 9.5 cm (+2.7 SD) at birth. Ossification center was already discernible bilaterally in coracoid process and distal femur at birth. In eight newborn infants with fetal hydrops of various other etiologies born in our institution, birth length ranged from -0.2 to -1.5 SD and thoracic spine length ranged from +0.5 to -1.7 SD, and neither ossification center of coracoid process nor distal femur were visible. The above data indicate that hydrops fetalis form of MPS VII is associated with intrauterine growth acceleration accompanied by early bone maturation. This feature may be useful in differentiating MPS VII associated hydrops fetalis from those of other etiologies.

Bone Development↗
PubMed1998

[A case of acute necrotizing encephalopathy of childhood with a good outcome].

We experienced a case of acute necrotizing encephalopathy of childhood with a good outcome. The disease continued for about three weeks, and the patient recovered with a sequela of mild left-hemiparesis. On the brain magnetic resonance imaging, abnormal intensity areas in the thalamus and putamen reduced size at an early stage of the disease. After 1 year, his mental and motor development seemed to be almost normal, but brain single photon emission computed tomography and electroencephalography were abnormal. Subclinical functional abnormalities persisted longer than had been expected.

Brain↗
PubMed1997

Cerebrospinal fluid tau levels in neurodegenerative diseases with distinct tau-related pathology.

Cerebrospinal fluid tau (CSF-tau) levels were quantified in 8 patients with frontotemporal dementia (FTD), 6 patients with progressive supranuclear palsy (PSP), 3 patients with corticobasal degeneration (CBD), and 6 patients with dementia with Lewy bodies (DLB). The CSF-tau levels were significantly increased in FTD and DLB, but not in PSP and CBD, compared to that previously reported in normal controls. Notably, the CSF-tau level in DLB was as high as that in Alzheimer's disease (AD). Our study suggests that tau may accumulate in the CSF of patients with certain neurodegenerative diseases other than AD and that measurement of CSF-tau may not distinguish AD from DLB.

Aged↗