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S Yamaguchi

Publications and source records attributed to S Yamaguchi.

At least 37 records · Page 2Linked to original sources
PubMed2004

Genome-wide survey of protein kinases required for cell cycle progression.

Cycles of protein phosphorylation are fundamental in regulating the progression of the eukaryotic cell through its division cycle. Here we test the complement of Drosophila protein kinases (kinome) for cell cycle functions after gene silencing by RNA-mediated interference. We observed cell cycle dysfunction upon downregulation of 80 out of 228 protein kinases, including most kinases that are known to regulate the division cycle. We find new enzymes with cell cycle functions; some of these have family members already known to phosphorylate microtubules, actin or their associated proteins. Additionally, depletion of several signalling kinases leads to specific mitotic aberrations, suggesting novel roles for familiar enzymes. The survey reveals the inter-digitation of systems that monitor cellular physiology, cell size, cellular stress and signalling processes with the basic cell cycle regulatory machinery.

AMP-Activated Protein Kinase Kinases↗
PubMed2004

Inhibition of endotoxin- and antigen-induced airway inflammation by fudosteine, a mucoactive agent.

We evaluated the effect of a mucoactive agent (-)-(R)-2-amino-3-(3-hydroxypropylthio) propionic acid (fudosteine), on airway inflammation using endotoxin- and antigen-induced models. Time courses of growth related oncogene/cytokine-induced neutrophil chemoattractant-1 (GRO/CINC-1) production, neutrophil migration and goblet cell hyperplasia were examined in endotoxin-induced rat airway inflammation. GRO/CINC-1 in bronchoalveolar lavage fluid (BALF) increased in response to intratracheal instillation of endotoxin and peaked within 4 h. Neutrophils in BALF and goblet cells on trachea peaked 24 and 96 h after endotoxin instillation, respectively. Fudosteine significantly inhibited increases in GRO/CINC-1 at 10-100 mg/kg, and neutrophils and goblet cells at 30 and 100 mg/kg. These results suggest that inflammatory events including neutrophil chemoattractant production and neutrophil migration play important roles for goblet cell hyperplasia in endotoxin-induced airway inflammation, and fudosteine inhibits goblet cell hyperplasia by inhibiting GRO/CINC-1 production and/or neutrophil migration. Furthermore, fudosteine (100 mg/kg) inhibited ovalbumin-induced eosinophil infiltration into BALF, suggesting it attenuates asthmatic inflammation.

Animals↗
PubMed2004

An immunohistochemical study of TIMP-3 expression in oesophageal squamous cell carcinoma.

Tissue inhibitor of metalloproteinase-3 (TIMP-3) inhibits the activity of matrix metalloproteinase, which may play an important role in carcinoma invasion and metastasis. We have investigated the relationship between TIMP-3 reduction and clinicopathological factors in oesophageal squamous cell carcinoma (ESCC). We examined tissue specimens that had been removed from 90 patients with thoracic oesophageal cancer who had undergone surgery between 1983 and 2001. Immunohistochemical staining was performed by the standard streptavidin-biotin method. Immunostaining of TIMP-3 was seen in the cytoplasm of cancer cells and normal oesophageal epithelial cells, particularly in cells located in shallow areas of the tumour. TIMP-3 preserved (+), moderate (+/-), and reduced (-) cases accounted for 30, 27, and 33 of the 90 patients, respectively (33, 30, 37%). Significant correlations were observed between TIMP-3 expression and depth of tumour invasion (P=0.001), number of lymph node metastases (P=0.003), infiltrative growth pattern (P=0.003), and disease stage (P=0.005). The survival rates of patients with TIMP-3 (-) cancer were significantly lower than those of patients with TIMP-3 (+) and TIMP-3 (+/-) cancer (P=0.0003). The mean 5-year survival rates of patients with TIMP-3 (+), (+/-), and (-) were 50, 58, and 21%, respectively. In conclusion, decreased expression of TIMP-3 protein correlates with invasive activity and metastasis. This makes the prognosis for patients with cancer that has lost TIMP-3 significantly less favourable than that for patients with cancer that has maintained TIMP-3.

Adult↗
PubMed2004

Three-dimensional observation of an helical hot structure during a sawtooth crash in the WT-3 tokamak.

Sawtooth crashes in an Ohmically heated plasma in the WT-3 tokamak have been observed by using soft x-ray computer tomography at three different poloidal cross sections around the torus. Initially, collapsing proceeds slowly with keeping the helical structure of an m = 1/n = 1 hot core around the torus. It accelerates as the helical hot structure is strongly deformed and fades away in the manner that the hot core at the high field side becomes obscure and disappears, while that at the low field side is deformed into a thin crescent aligned along the inversion circle, which survives even at the completion of the crash.

Journal Article↗
PubMed2004

A new diagnostic test for VLCAD deficiency using immunohistochemistry.

BACKGROUND: Muscle pathology is often unhelpful in elucidating the specific underlying abnormality in patients with metabolic myopathy with rhabdomyolysis, including very-long chain acyl-CoA dehydrogenase (VLCAD) deficiency. Biochemical analyses require large amounts of biopsy samples for each enzyme assay. OBJECTIVE: To develop a more efficient diagnostic method for VLCAD deficiency. METHODS: The authors performed immunohistochemical analysis using an antibody to VLCAD on muscles from 344 patients (226 men and 118 women) without a specific diagnosis who had at least one of the following symptoms: myoglobinuria, high CK level, muscle pain, muscle stiffness, sudden infant death syndrome, and Reye-like syndrome. RESULTS: Immunoreactivity to VLCAD was absent or markedly reduced in 13 patients. Biochemical analyses confirmed that all these patients had low enzymatic activity and reduced amount of protein. They all had the myopathic phenotype. The authors identified homozygous or compound heterozygous mutations in all of them. All recombinant proteins had reduced enzymatic activity except for 128G>A (G43D) and 796C>G (P266A) mutants, indicating that they are neutral polymorphisms. CONCLUSIONS: The new screening method for the detection of VLCAD deficiency using an immunohistochemical technique identified 13 new Japanese patients with VLCAD deficiency.

Acyl-CoA Dehydrogenase, Long-Chain↗
PubMed2004

Phylogenetic analysis of avian infectious bronchitis virus strains isolated in Japan.

To define the origin and evolution of recent avian infectious bronchitis virus (IBV) in Japan, a genetic analysis was performed. By phylogenetic analysis based on the S1 gene including the sequence of the hypervariable regions, IBV isolates in Japan were classified into five genetic groups, which included two already-known groups (Mass and Gray). Among them, three major genetic groups were associated with the recent outbreaks of IB in Japan. One group is indigenous to Japan and could not be placed within the known existing groups in other countries. The remaining two groups, which have emerged recently, are related to isolates in China and Taiwan.

Amino Acid Sequence↗
PubMed2004

Hydroxyapatite particles as a controlled release carrier of protein.

This study examines the possibility of using hydroxyapatite (HAp) particles as a controlled release carrier of protein. In order to achieve effective protein release from HAp particles, it is necessary to regulate the conjugated amount of protein on HAp and the resorption of HAp. HAp particles were synthesized at different temperatures (40 degrees C, 60 degrees C, 80 degrees C) in wet condition and the physico-chemical properties of synthesized HAp particles were examined. HAp particles synthesized at low temperatures showed low crystallinity, high solubility and large specific surface area. The useful growth factors for bone regeneration, such as BMP, bFGF and TGF-beta, are basic proteins, so cytochrome c (pI=10.2) was used as a model protein and the adsorptive property of protein on HAp particles was investigated. The protein adsorption on HAp particles changed depending on its specific surface area and the chart of protein adsorption on HAp particles showed a typical Langmuir curve. These findings suggest that the adsorbed amount of protein on HAp particles could be regulated by HAp synthesizing temperature and the concentrations of protein solution. The release kinetics of protein from the HAp particles that adsorbed the protein (HAp-pro) was also evaluated in different pH solutions (pH 4.0 and 7.0). The released protein gradually increased time dependently when HAp-pro were immersed in pH 4.0 solution, but the released protein was significantly smaller when HAp-pro were immersed in pH 7.0 solution. Moreover, the release rate of protein from HAp-pro differed in each HAp that was synthesized at different temperatures, suggesting that the release of protein from HAp-pro depended on HAp resorption. These results suggest that HAp particles synthesized at different temperature are useful as a controlled release carrier of protein.

Adsorption↗
PubMed2004

Role of women in medicine: a look at the history, the present condition and the future status of women in the surgical field, especially neurosurgery.

We have analyzed the historical background of women's progress in medicine in Japan and the role of female neurosurgeons as models for the next generation. Female neurosurgeons were asked to complete a questionnaire regarding their professional life in detail and the problems they are facing while managing their personal life after getting married and having a child. Some feel that there remain some constraints at work for being a female, due to their male colleagues who are not so understanding in nature. The younger generation is not so keen on joining the neurosurgical branch as their life career due to hard work and complete dedication demanded by neurosurgery. It is not easy for all to manage a neurosurgical career along together with a married life and children. Hence it is now time for those successful female neurosurgeons to become role models. Government can play an important role in these social reforms by coming up with programs to give social security to females and initiate programs for child care for married females pursuing such a demanding profession. Certain measures to encourage females to take up surgery are providing more time by arranging care for babies and families, flexibility in working hours, in addition to having a considerate husband and a considerate chief of department and senior staff. Departmental policies need to be completely impartial and should promote everyone based on their skills and knowledge. Women neurosurgeons need to get together and discuss all these issues so that the younger generation will not hesitate to take up this profession and become stalwarts of neurosurgery like their male counterparts.

Adult↗
PubMed2004

Cytological basis for enhancement of radiation-induced mortality by Friend leukaemia virus infection.

PURPOSE: To analyse the cytological basis for enhancement of radiation-induced mortality by Friend leukaemia virus infection. MATERIALS AND METHODS: Cellularity in haematopoietic tissues of C3H mice infected with FLV and/or whole-body irradiation was examined. RESULTS: When mice were treated with a sublethal dose (3 Gy) of irradiation at 1 week after virus infection, most manifested a severe loss of cellularity in the spleen, bone marrow and peripheral blood 2 weeks after irradiation. More than 90% of the mice died within 1 month post-irradiation. However, this deleterious effect of virus infection on the survival of irradiated mice was observed only when they were irradiated at around 1 week after virus inoculation. Strain differences in the sensitivity to this effect were observed among virus-sensitive strains of mice. CONCLUSIONS: The results indicate that Friend leukaemia virus infection can cause enhancement of radiation sensitivity of haematopoietic cells in host animals in a restricted manner in terms of genetic background and the interval between infection and irradiation.

Animals↗
PubMed2004

Isolation and characterization of mesenchymal progenitor cells from chorionic villi of human placenta.

BACKGROUND: BM-derived mesenchymal stem cells (MSC) are attractive sources for autotransplantation with no risk of rejection, but the use of these cells bas problems, including the necessity of harvesting BM from donors, the donors' age-dependency, limitation to autologous use and difficulty of use for patients with hereditary diseases. We report a method of isolating placenta-derived mesenchymal progenitor cells (PDMPC) that can be used as an alternative source of MSC. METHODS: We isolated PDMPC from human fetal chorionic villi using the explant culture method, from placentas collected after neonatal delivery (38-40 weeks of gestation). The PDMPC were characterized by morphologic and immunophenotypic analysis. The differentiation ability of mesenchymal and neural lineages was detected using specific culture conditions and determined by morphology, reverse transcription(RT)-PCR, histochemical staining and immunocytostaining. RESULTS: The PDMPC all originated from fetal chorionic villi, as confirmed by fluorescence in situ hybridization analysis. The PDMPC population consisted of spindle-shaped cells and large flat cells. The PDMPCexpressed CD13, CD44, CD73, CD90, CDIO5 and HLA class I as surface epitopes, but not CD31, CD34, CD45 and HLA-DR. These cells differentiated into osteocytes, chondrocytes and adipocytes under specific culture conditions, and were also induced to form neural-like cells. DISCUSSION: Our study shows that PDMPC can differentiate into mesenchymal lineages and be induced to form neural-like cells. Thus, PDMPCisolated from chorionic villi of placenta may provide a novel source for the research of stem and progenitor cells in placenta, cell therapy and regenerative medicine, particularly as a source of allogenic mesenchymal stem and progenitor cells with little ethical conflict and various advantages

Antigens, CD↗
PubMed2004

Role of peptide antigen for induction of inhibitory antibodies to Streptococcus mutans in human oral cavity.

The alanine-rich repeating region (A-region) in the surface protein antigen (PAc) of Streptococcus mutans has received much attention as an antigenic component for vaccines against dental caries. The PAc (residue 361-386) peptide in the A-region possesses a multiple binding motif (L- -V-K- -A) to various HLA-DR molecules and a B-cell core epitope (- Y- - -L- -Y- - - -) that recognizes the inhibiting antibody to S. mutans. In the present study, we investigated the immunogenicity of the PAc (361-386) peptide in humans and regulators of induction of the anti-PAc (361-386) peptide IgA antibody (aPPA) in saliva. The PAc (361-386) peptide was confirmed as an ideal peptide antigen for induction of the inhibiting antibody to S. mutans in 151 healthy human subjects (36.6 +/- 12.6 years old) by quantitative analyses of oral bacteria and ELISA, as the aPPA titre in human saliva decreased significantly in an age-dependent manner. Homozygous DRB1*0405 and 1502, and heterozygous DRB1*0405/1502 showed a negative association with production of aPPA and tended to reduce the number of total streptococci in saliva. In contrast, the DRB1*1501 allele was significantly correlated with a high level of induction of the antibodies, and also tended to reduce lactobacilli and mutans streptococci. Further, peptide immunogenicity was confirmed in NOD-SCID mice grafted with human peripheral blood mononuclear cells. Our results indicate that the interplay between regulators such as age, DRB1 genotype, cytokines, and peptide immunogenicity may provide a potential means for developing a vaccine useful for the prevention of dental caries as well as their diagnosis.

Adult↗
PubMed2003

Amiloride-sensitive epithelial Na+ channel currents in surface cells of rat rectal colon.

Surface cells of the mammalian distal colon are shown to molecularly express the amiloride-sensitive epithelial Na+ channel composed of three homologous subunits (alpha-, beta-, and gamma-ENaC). However, because basic electrophysiological properties of amiloride-sensitive Na+ channels expressed in these cells are largely unknown at the cellular level, functional evidence for the involvement of the subunits in the native channels is incomplete. Using electrophysiological techniques, we have now characterized functional properties of native ENaC in surface cells of rectal colon (RC) of rats fed a normal Na+ diet. Ussing chamber experiments showed that apical amiloride inhibited a basal short-circuit current in mucosal preparation of RC with an apparent half-inhibition constant (Ki) value of 0.20 microM. RT-PCR analysis confirmed the presence of transcripts of alpha-, beta-, and gamma-rENaC in rectal mucosa. Whole cell patch-clamp experiments in surface cells of intact crypts acutely isolated from rectal mucosa identified an inward cationic current, which was inhibited by amiloride with a Ki value of 0.12 microM at a membrane potential of -64 mV, the inhibition being weakly voltage dependent. Conductance ratios of the currents were Li+ (1.8) > Na+ (1) >> K+ ( approximately 0), respectively. Amiloride-sensitive current amplitude was almost the same at 15 or 150 mM extracellular Na+, suggesting a high Na+ affinity for current activation. These results are consistent with the hypothesis that a heterooligomer composed of alpha-, beta-, and gamma-ENaC may be the molecular basis of the native channels, which are responsible for amiloride-sensitive electrogenic Na+ absorption in rat rectal colon.

Amiloride↗
PubMed2003

In vivo distribution of receptor for ecotropic murine leukemia virus and binding of envelope protein of Friend Murine leukemia virus.

Ecotropic infection by Murine leukemia virus (MuLV) infection is initiated by the interaction between the receptor-binding domain of the viral surface glycoprotein (SU) and the cell-surface receptor, mCAT-1. To study the in vivo localization of viral binding site in mice, green fluorescence protein (GFP)-tagged Friend SU (F-SU/GFP) was incubated with tissue sections. Lymphohematopoietic organs and a part of the glandular tissues of C3H as well as C57BL/6 mice revealed positive signals for F-SU/GFP binding on the cell surface. In contrast, C4W mice, which is a partial congenic mouse strain carrying the Fv-4 (r) gene on a BALB/c genetic background, exhibited negative signals in most of the organs except for a very weak binding in the pancreas. The expression of mCAT-1 mRNA determined by reverse transcriptase (RT)-polymerase chain reaction (PCR) revealed a similar distribution in C3H, C57BL/6 and C4W mice. Most of the organs including lymphohematopoietic organs and glandular organs revealed significant expression of mRNA for mCAT-1 gene, while the liver, heart and muscle did not. The results from binding assay were consistent with the fact that Friend MuLV-induced pathogenesis was usually associated with lymphohematopoietic systems, although mRNA expression for mCAT-1 was rather ubiquitous. The discrepancy between F-SU/GFP binding and mRNA expression for mCAT-1 in lymphohematopoietic organs of C4W mice would support the receptor interference effect by the Fv-4 (r) gene causing the resistance of C4W mouse to Friend MuLV infection.

Animals↗
PubMed2003

The mitochondrial acetoacetyl-CoA thiolase (T2) deficiency in Japanese patients: urinary organic acid and blood acylcarnitine profiles under stable conditions have subtle abnormalities in T2-deficient patients with some residual T2 activity.

Mitochondrial acetoacetyl-CoA thiolase (T2) deficiency is an inborn error of metabolism affecting isoleucine and ketone bodies in the catabolic process. Mutation analysis and expression analysis of mutant cDNAs have facilitated the division of T2-deficient patients into two groups: those with null mutations in either allele (group 1) and those with mutation(s) retaining some residual T2 activity in at least one of two mutant alleles (group II). Among 5 Japanese T2-deficient patients, GK01 belonged to group I and the other patients (GK19, GK19B, GK30 and GK31) to group II. As we have suggested previously, the severity of ketoacidotic episodes in the group II patients was similar to that in the group I patient. However, the urinary organic acid and blood spot acylcarnitine profiles under stable conditions differed between the two groups. The group I patient had typical profiles for the T2 deficiency. In contrast, in all four patients in group II, tiglylglycine was not or was only faintly detected and the 2-methyl-3-hydroxybutyrate levels were less than the cutoff value. Their tiglylcarnitine levels were within the normal range and 2-methyl-3-hydroxy-, butyrylcarnitine was detected just around the cutoff value in our newborn screening pilot test. Hence, these analyses under stable conditions are not reliable for diagnosing the T2 deficiency in the group II patients. The T2 deficiency (group II) can be misdiagnosed as normal if these analyses are performed under nonepisodic conditions and possibly during the newborn screening for inborn errors of metabolism.

Acetoacetates↗
PubMed2003

Normalization of low biotinidase activity in a child with biotin deficiency after biotin supplementation.

We report findings in a Japanese boy with severe skin rash attributable to biotin deficiency. The patient had an intracranial malformation and developed biotin deficiency due to tube feeding with a single formula for over one year. Results of urinary organic acid analysis were consistent with multiple carboxylase deficiency, and low biotinidase activity was also observed. After biotin supplementation, the skin rash improved and biotinidase activity normalized. We speculate that biotin is one regulating factor in the biosynthesis of biotinidase.

Biotin↗
PubMed2003

The allelic loss of chromosome 3p25 with c-myc gain is related to the development of clear-cell renal cell carcinoma.

To explore the role of allelic losses at 3p25 and genetic alterations of chromosome 8, we investigated the relationships between genetic alterations in these chromosomal regions and clinicopathologic findings (such as tumor size and grade), by employing fluorescence in situ hybridization (FISH). Fifty Japanese clear-cell renal cell carcinomas (RCCs) were examined by dual-color FISH using cosmid DNA probes for 3p25.1-25.3 combined with probes for chromosome 3 centromere, 8p12, 8p21.1, 8p21.3, 8p22 and 8q24.12-24.13 (c-myc), and chromosome 8 centromere. Deletion at 3p25.1-25.3 was detected in 38 patients (76%), while 8p12 deletion, 8p21.1 deletion, 8p21.3 deletion, 8p22 deletion and c-myc gain were detected in 23 (46%), 25 (50%), 25 (50%), 25 (50%), and 20 patients (40%), respectively. There was a significant correlation between 8p21.1 deletion, 8p21.3 deletion and 8p21.1 deletion with c-myc gain and tumor grade (p = 0.04, 0.04 and 0.02, respectively). Deletions at 8p21.1 and 8p21.3 with 3p deletion were significantly related to tumor grade; the statistical significance was identical to that of sole 8p deletion with tumor grade. The deletion at 3p25.1-25.3 with c-myc gain showed a significant correlation with tumor size, indicating an association with tumor progression. Our results suggest that the allelic loss of chromosome 3p25 with c-myc gain is related to the development of clear-cell RCC.

Carcinoma, Renal Cell↗
PubMed2003

Effects of pulmonary artery remodeling on pulmonary circulation after lung volume reduction surgery.

BACKGROUND: Significant pulmonary hypertension during exercise has been observed in patients with severe chronic obstructive pulmonary disease. Although favorable effects on pulmonary function and dyspnea symptoms have been demonstrated, the influence of lung volume reduction surgery (LVRS) on the pulmonary hypertension during exercise is still a controversial subject. METHODS: A pulmonary function test and 6-minute walking test were performed before and 3, 6, 12 and 24 months after LVRS (n = 12). Pulmonary hemodynamics at rest and during exercise was studied 6 months after operation. Morphology was examined in pulmonary arteries with external diameters of 100 - 200 micro m in the resected lung, and the wall thickness (defined as intima plus media) and percentage wall thickness (percentage wall thickness of the external diameter) of the pulmonary artery were calculated. RESULTS: LVRS improved early-phase pulmonary function and 6-minute walking distance. Although the increase in pulmonary capillary wedge pressure during exercise was significantly ameliorated, exercise pulmonary hypertension did not change after LVRS. The percent wall thickness was highly correlated with Delta Ppa (difference between mean pulmonary artery pressure at rest and mean pulmonary artery pressure during exercise) not only before, but also 6 months after LVRS. CONCLUSION: LVRS has no significant influence on exercise-induced pulmonary hypertension in patients with severe emphysema. From a histological analysis of the pulmonary artery in the resected lung, remodeling the pulmonary artery that may exist in the remaining lung is possibly one of the important factors preventing postoperative improvement in exercise pulmonary hypertension in patients with chronic obstructive pulmonary disease.

Aged↗