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R Sasaki

Publications and source records attributed to R Sasaki.

At least 55 records · Page 3Linked to original sources
PubMed2000

Characterization and comparative study of the rrn operons of alkaliphilic Bacillus halodurans C-125.

The ribosomal RNA operons (rrn) of alkaliphilic Bacillus halodurans C-125 were characterized and compared with those of B. subtilis. We isolated clones containing rrn operons from a lambda phage library of the C-125 chromosome, and the complete nucleotide sequence of each was determined. Eight rrn operons were identified by PFGE analysis of the C-125 chromosome digested with I-CeuI. The transcriptional orientation of the rrn operons mapped on the chromosome by Southern hybridization analysis was the same as the direction of replication of the chromosome. These operons were designated as rrnA-H, starting from the oriC locus in clockwise rotation. Sequence and structural analyses of these operons suggested that six of the rrn operons in the C-125 chromosome, rrnA, rrnB, rrnC-rrnD, rrnE, and rrnH, correspond to rrnO, rrnA, rrnJ-rrnW, rrnI, and rrnD in B. subtilis, whereas the other rrn operons (rrnF and rrnG) were specifically observed in C-125. The rrn loci were positioned from 0 degrees to 90 degrees on the physical map, with the oriC locus assigned the position zero degrees. Two ORFs annotated as tnpA and ykfC, whose gene products are likely to act as transposases, were found downstream of these six operons. Comparative analysis of the 16S-23S and 23S-5S ITS (internally transcribed sequence) regions of B. halodurans C-125 and those of B. subtilis revealed that the ITS regions in C-125 were much longer than those in B. subtilis. There was no substantial difference in the length of potential promoter sequences in B. halodurans and B. subtilis.

Alkalies↗
PubMed2000

The clinical utility of measuring total PSA, PSA density, gamma-seminoprotein and gamma-seminoprotein/total PSA in prostate cancer prediction.

BACKGROUND: To evaluate whether serum total prostate-specific antigen (PSA), PSA density (serum total PSA level divided by prostate volume), gamma-seminoprotein and gamma-seminoprotein/total PSA ratio could predict prostate cancer (PCa) prior to biopsy. METHODS: A total of 316 consecutive patients who had undergone transrectal prostate biopsy and/or transurethral resection were examined. The prostate volume was determined by transrectal ultrasonography (TRUS) and the ability of the above-mentioned four variables to distinguish PCa from benign prostatic hyperplasia (BPH) was evaluated. RESULTS: PCa was detected in 61 cases. Receiver-operating characteristic (ROC) analysis revealed that both the PSA density and serum total PSA were the most useful predictors of PCa among the four variables. For the patients with a serum total PSA level of 4.1-10.0 ng/ml, PSA density was significantly more accurate than total PSA (p < 0.005). An optimum PSA density value of 0.18 was chosen as a cutoff because it showed the highest sum of sensitivity and specificity, 92 and 54%, respectively. Using this PSA density cutoff, the number of biopsies could have been reduced to 57 from 63% when compared with a PSA density of 0.15. CONCLUSIONS: PSA density was significantly more accurate than other variables in predicting PCa. To avoid unnecessary biopsies, the PSA density cutoff value of 0.18 would be recommendable for determining a prostate biopsy for Japanese males with a serum total PSA level of 4.1-10.0 ng/ml.

Aged↗
PubMed2000

The oviduct produces erythropoietin in an estrogen- and oxygen-dependent manner.

Previously, we showed that erythropoietin (Epo) is produced in the mouse uterus, where Epo is indispensable for estrogen (E(2))-dependent angiogenesis. Expression of uterine Epo mRNA is stimulated by E(2) and hypoxia. The hypoxic induction requires the presence of E(2). In the present study, we examined other female reproductive organs in the mouse with respect to Epo mRNA expression and its stimuli (E(2) and hypoxia)-induced changes. Although Epo mRNA expression was seen in the ovary and oviduct, the E(2)-induced stimulation of Epo mRNA was found only in the oviduct. The E(2)-induced stimulation in the oviduct was transient and rapidly downregulated. Epo mRNA expression in the oviduct was hypoxia inducible, in both the presence and the absence of E(2). E(2)-dependent production of Epo and its mRNA expression were also found by use of cultured oviducts. The E(2) action is probably mediated through the E(2) receptor, and de novo protein synthesis is not required for E(2) induction of Epo mRNA. In the oviduct, the ampulla and isthmus regions produce Epo.

Animals↗
PubMed2000

Tissue-specific regulation of erythropoietin production in the murine kidney, brain, and uterus.

Erythropoietin (Epo) produced by the kidney regulates erythropoiesis. Recent evidence suggests that Epo in the cerebrum prevents neuron death and Epo in the uterus induces estrogen (E(2))-dependent uterine angiogenesis. To elucidate how Epo expression is regulated in these tissues, ovariectomized mice were given E(2) and/or exposed to hypoxia, and the temporal patterns of Epo mRNA levels were examined. Epo mRNA levels in the kidney and cerebrum were elevated markedly within 4 h after exposure to hypoxia. Although the elevated level of Epo mRNA in the kidney decreased markedly within 8 h despite continuous hypoxia, the high level in the cerebrum was sustained for > or = 24 h, indicating that downregulation operates in the kidney but not in the brain. E(2) transiently induced Epo mRNA in the uterus but not in the kidney and cerebrum. Interestingly, the uterine Epo mRNA was hypoxia inducible only in the presence of E(2). Thus Epo expression appears to be regulated in a tissue-specific manner, endorsing the tissue-specific functions of Epo.

Animals↗
PubMed2000

Identification of a sequential B-cell epitope on major allergen (Cry j 1) of Japanese cedar (Cryptomeria japonica) pollen in mice.

BACKGROUND: Japanese cedar (Cryptomeria japonica; CJ) pollinosis is one of the most common allergic diseases in Japan. B cell epitopes on Cry j 1, a major allergen of CJ pollen, have been analyzed by the specific monoclonal antibodies to Cry j 1, and most of these epitopes may be conformational, but no previous report has addressed the analysis of sequential epitope mapping with synthetic peptides. The main purpose of the present study is to identify IgE and IgG B cell epitopes on Cry j 1 by using a synthetic peptide approach in mice. METHODS: We synthesized 35 overlapping peptides that cover the entire length of Cry j 1 and examined whether mouse IgE and IgG antibodies produced by immunization with Cry j 1 reacted to the Cry j 1 peptides. RESULTS AND CONCLUSION: We found that mouse IgE and IgG antibodies reacted strongly to Cry j 1 peptide No. 15 ((141)GVEPVHPQDGDALTLRTATN(160)), though those antibodies did not react with other peptides. IgE and IgG antibody binding to peptide No. 15 was completely inhibited by Cry j 1 and the peptide. To determine the minimum epitope in peptide No. 15, we conducted an ELISA inhibition test. IgE and IgG antibody binding to peptide No. 15 was inhibited by smaller peptides of this peptide. We found the core of the epitope to be (145)VHPQDGDA(152).

Allergens↗
PubMed2000

Erythropoietin: multiple physiological functions and regulation of biosynthesis.

Erythropoietin (Epo), which is produced by the kidney in the adult and by the liver in the fetus, increases red blood cells by supporting the survival of erythroid progenitor cells and stimulating their differentiation and proliferation via binding to Epo receptor (EpoR). The main signal in the control of Epo production is oxygen; hypoxia stimulates Epo production through activation of Epo gene transcription. Tremendous progress in our understanding of molecular mechanisms of Epo action on erythroid cells and regulation of the Epo production has been made by manipulation of cDNAs and genes of Epo and EpoR. Studies on hypoxic induction of Epo gene transcription led to the identification of hypoxia-inducible factor (HIF-1), a transcriptional factor, that functions as a global regulator of hypoxic gene expression. Paracrine Epo/EpoR systems that are independent of the endocrine erythropoietic system (kidney/bone marrow) have been found in the central nervous system and uterus. Novel functions of Epo at these local sites and tissue-specific regulation of Epo production including a newly found potent regulator (estrogen) have been proposed. The tissue-specific regulation rationalizes the specific functions of Epo produced by individual tissues.

Adult↗
PubMed2000

[The quality of life after radical prostatectomy measured by general health questionnaire and visual analogue scales].

OBJECTIVES: The impact of radical prostatectomy on the quality of life (QOL) of patients were evaluated. MATERIALS AND METHODS: A total of 22 patients who underwent radical prostatectomy for clinically localized prostate cancer entered this study. Patients were asked to complete a questionnaire containing the general health questionnaire (GHQ) and a series of questions evaluating voiding function, incontinence and sexual dysfunction before and after the operation. In addition, the visual analogue scaled (VAS) questionnaire containing incontinence and sexual dysfunction was applied. RESULTS: No significant differences in GHQ were found between pre- and post operative status, but disease-targeted QOL such as sexual function was affected after the radical prostatectomy. In the points of incontinence and sexual dysfunction, VAS questionnaire significantly correlated with those of categorical questionnaires. CONCLUSIONS: There results suggest that GHQ is not affected, but disease-targeted QOL in some categories of sexual function is affected by radical prostatectomy, and that VAS questionnaires are not only useful for assessing the disease-targeted QOL but also easy to quantify QOL of the patients.

Aged↗
PubMed2000

[Low-dose prednisolone therapy for idiopathic thrombocytopenic purpura].

Prednisolone (PSL) is widely used for the treatment of idiopathic thrombocytopenic purpura (ITP). We compared the effects of a relatively low dose (0.5 mg/kg/day, LD group) of PSL and the conventional dose (1.0 mg/kg/day, CD group) on 59 ITP patients. Twenty-six patients were treated with low-dose PSL, and 23 patients with the conventional dose. No statistically significant difference was observed in the complete remission rates for the LD group (35%) and the CD group (39%). However, the mean duration of hospitalization was significantly (p < 0.001) shorter for LD group patients than for patients in the CD group (20 days versus 50 days, respectively). In conclusion, low-dose PSL may be as effective as the conventional dose and capable of reducing the cost of hospitalization, thus, improving the quality of life for patients with ITP.

Anti-Inflammatory Agents↗
PubMed1999

Unidirectional transport from apical to basolateral compartment of cobalt ion in polarized Madin-Darby canine kidney cells.

Renal transport of Co2+ was studied by use of cultured MDCK cells with cell polarity. Cells imported 57Co2+ from the apical membrane exclusively, while uptake from the basolateral membrane was minute. Apical uptake was time-, concentration-, pH-, and temperature- dependent and the dose-dependency curve was saturable, indicating that a carrier-mediated influx process operates in the apical membrane. The substrate specificity and other properties of this Co2+ transport process are distinct from those of a transporter DCT1, divalent cation transporter 1, with unusually broad substrate specificity including Co2+. Radioactive Co2+ added from the apical side appeared in the basolateral side, while there was only slight movement of Co2+ from the basolateral to apical side, indicating that this unidirectional transepithelial passage of Co2+ is not caused by the paracellular diffusion, but by the basolateral export of the cellular Co2+ uptake from the apical membrane. Our results may indicate the presence of a novel vectorial transport system responsible for the reabsorption of Co2+ from the glomerular filtrate.

Animals↗
PubMed1999

Mutational analysis and genotype-phenotype correlation of 29 unrelated Japanese patients with X-linked adrenoleukodystrophy.

BACKGROUND: X-linked adrenoleukodystrophy (ALD) is an inherited disease characterized by progressive neurologic dysfunction, occasionally associated with adrenal insufficiency. The classic form of ALD usually has onset in childhood (childhood cerebral ALD), with rapid neurologic deterioration leading to a vegetative state. Adult-onset cerebral ALD also presents with rapidly progressive neurologic dysfunction. Milder phenotypes such as adrenomyeloneuropathy and Addison disease only also have been recognized. Despite discovery of the causative gene, a molecular basis for the diverse clinical presentations remains to be elucidated. OBJECTIVES: To conduct mutational analyses in 29 Japanese patients with ALD from 29 unrelated families, to obtain knowledge of the spectrum of mutations in this gene, and to study genotype-phenotype correlations in Japanese patients. METHODS: The 29 patients comprised 13 patients with childhood cerebral ALD, 11 patients with adult-onset cerebral ALD, and 5 patients with adrenomyeloneuropathy. We conducted detailed mutational analyses of 29 unrelated Japanese patients with ALD by genomic Southern blot analysis and direct nucleotide sequence analysis of reverse transcriptase-polymerase chain reaction products derived from total RNA that was extracted from cultured skin fibroblasts, lymphoblastoid cells, or peripheral blood leukocytes. RESULTS: Three patients with adult-onset cerebral ALD were identified as having large genomic rearrangements. The remaining 26 patients were identified as having 21 independent mutations, including 12 novel mutations resulting in small nucleotide alterations in the ALD gene. Eighteen (69%) of 26 mutations were missense mutations. Most missense mutations involved amino acids conserved in homologous gene products, including PMP70, mALDRP, and Pxa1p. The AG dinucleotide deletion at position 1081-1082, which has been reported previously to be the most common mutation in white patients (12%-17%), was also identified as the most common mutation in Japanese patients (12%). All phenotypes were associated with mutations resulting in protein truncation or subtle amino acid changes. There were no differences in phenotypic expressions between missense mutations involving conserved amino acids and those involving nonconserved amino acids. CONCLUSIONS: There are no obvious correlations between the phenotypes of patients with ALD and their genotypes, suggesting that other genetic or environmental factors modify the phenotypic expressions of ALD.

Adolescent↗
PubMed1999

A novel mutation in the gene for the adult skeletal muscle sodium channel alpha-subunit (SCN4A) that causes paramyotonia congenita of von Eulenburg.

BACKGROUND: Paramyotonia congenita (PMC) of von Eulenburg is an autosomal dominant muscular disease characterized by exercise- and cold-induced myotonia and weakness. To date, 18 missense mutations in the adult skeletal muscle sodium channel alpha-subunit (SCN4A) gene have been identified to cause a spectrum of muscular diseases, including PMC of von Eulenburg, PMC without cold paralysis, potassium-aggravating myotonia, and hyperkalemic periodic paralysis. However, no obvious correlations can be made between the location or nature of amino acid substitutions in SCN4A and its clinical phenotypes. OBJECTIVE: To describe clinical and genetic features of a family with PMC of von Eulenburg. RESULTS: A Japanese family with cold-induced myotonia and weakness was diagnosed as having PMC of von Eulenburg. This phenotype was identified to be caused by a novel mutation that substituted a glutamic acid residue for a highly conserved glycine residue in the fourth transmembrane segment (S4) of domain IV. This predicted a decrease in positive charge specific for the S4. CONCLUSION: In addition to the G1456E identified in this study, 4 mutations that cause a decrease in positive charge in the S4/D4 are associated with the phenotype of PMC of von Eulenburg. This provides an important genotype-phenotype correlation in sodium channelopathies.

Adult↗
PubMed1999

HGF activates signal transduction from EPO receptor on human cord blood CD34+/CD45+ cells.

Hepatocyte growth factor (HGF) is a multifunctional cytokine with early hematopoiesis-stimulatory activity. Here, we focus on its erythropoiesis-stimulatory effect on highly purified human hematopoietic progenitor cells (CD34+/CD45+ cells) derived from the cord blood. In immunoblot analyses, c-met protein (a receptor of HGF) was detected in the CD34+/CD45+ cells, although the expression levels were different among samples. The c-met expression was facilitated by incubation of the cells with stem cell factor (SCF) or interleukin 3 (IL-3), even if the expression level had been low. IL-6, G-CSF, or erythropoietin (EPO) did not show such a stimulatory effect on the c-met expression of the cells. When HGF was added to the CD34+/CD45+ cells in the presence of SCF, the numbers of CD36+/CD11b- cells (very early erythroid lineage cells) and BFU-E increased. EPO-dependent tyrosine phosphorylation of Stat 5 also increased, but the EPO receptor (EPO-R) expression remained unchanged in the CD34+/CD45+ cells treated with SCF + HGF. Our present study suggests that stimulation of the HGF/c-met signal is concomitant with induction of c-met protein by SCF. The subsequent enhancement of signal transduction via the activation of Stat 5 from the EPO-R plays a crucial role in the commitment of hematopoietic stem cells into erythroid lineage cells.

Antigens, CD34↗
PubMed1999

Circulating prostate-specific antigen mRNA during radical prostatectomy in patients with localized prostate cancer: with special reference to neoadjuvant hormonal therapy.

To determine the potential risk of hematogenous dissemination of prostate cancer cells during radical prostatectomy (RP), we investigated the pre- and intraoperative circulating prostate-specific antigen (PSA) mRNA in patients with clinically localized prostate cancer, with special reference to neoadjuvant hormonal therapy (NHT). Using a nested reverse transcriptase (RT) polymerase reaction (PCR) assay, PSA mRNA in the peripheral blood was evaluated pre- and postoperatively in a total of 23 patients, 10 of whom received NHT with antiandrogens. The RT-PCR assay employed detected one LNCaP cell in 10(7) mononuclear blood cells, and showed no positive signal in the blood samples from all 15 healthy controls. Pre- and intraoperative circulating PSA mRNA was positive in 11 (48%) and 18 patients (78%), respectively. All 11 patients with positive preoperative PSA mRNA continued to be positive during RP, and seven (58%) of 12 patients with negative preoperative PSA mRNA had a positive conversion. Although the patients' ages, preoperative serum PSA values and clinical or pathological stages were not associated with the pre- and intraoperative PSA mRNA results, the NHT group showed a significantly lower incidence of preoperative PSA mRNA positivity (2/10) than the group receiving RP alone (9/13) (20% vs 69%, P = 0.036). NHT, however, showed no suppressive effect on either intraoperative positivity or positive conversion of circulating PSA mRNA. The present study suggests that a substantial number of patients receiving RP are at risk of hematogenous dissemination, and NHT with antiandrogens has a minimal or no suppressive effect on the circulating PSA mRNA during surgical manipulation of the prostate. Because the clinical significance of circulating cancer cells remains to be determined, long-term follow-up in association with the circulating cancer cells assessed by the RT-PCR is essential in order to establish the role of molecular staging as well as NHT.

Aged↗
PubMed1999

Genetic analysis of the chromosome of alkaliphilic Bacillus halodurans C-125.

Seventeen Sse8387I linking clones isolated from the chromosome of Bacillus halodurans C-125 for the purpose of constructing a physical map were sequenced and analyzed by comparison with the BSORF database and the nonredundant protein databank. The orientations of Sse8387I or AscI linking clones serving to join adjacent fragments were determined by southern blot analysis using specific DNA probes. One-third of the open reading frames (ORFs) identified in the Sse8387I linking clones showed no significant similarity to any protein so far reported. The ORFs showing significant similarities to those of Bacillus subtilis were mapped in the chromosome of strain C-125, and the locations of the putative genes on the map were not well conserved between B. halodurans C-125 and B. subtilis.

Bacillus↗
PubMed1999

Novel chloride channel gene mutations in two unrelated Japanese families with Becker's autosomal recessive generalized myotonia.

We investigated the skeletal muscle voltage-gated chloride channel gene (CLCN1) in two unrelated Japanese patients with Becker's myotonia congenita. The non-myotonic parents of each patient were consanguineous. The proband of each family shares generalized myotonia, transient weakness after rest, and leg muscle hypertrophy. However, the disease severity related to the degree of myotonia differed, even in view of the response to long train nerve stimulation tests. CLCN1 gene analysis revealed a novel Ala659Val missense mutation identified to be homozygous in the more severe patient, while a novel Gln445Stop nonsense mutation was present in the other patient. Both mutations were absent in 90 Japanese normal controls. This is the first report of Japanese cases of Becker's myotonia congenita with CLCN1 gene mutations.

Adult↗