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Biomedical subjects

S Yamazaki

Publications and source records attributed to S Yamazaki.

At least 55 records · Page 3Linked to original sources
PubMed2001

Cloning and sequencing of a gene encoding a novel salt stress-induced membrane protein from Rhodobacter sphaeroides f. sp. dentrificans.

The gene encoding a membrane protein, SspA, induced under salt stress conditions was cloned and sequenced from a photosynthetic bacterium, Rhodobacter sphaeroides f. sp. denitrificans IL106. A single open reading frame consisting of 972 base pairs that encoded a polypeptide composed of a signal peptide of 24 amino acids and a mature protein of 300 amino acids (Mr 33,386) was found. A database search failed to detect any highly homologous sequences, indicating that SspA is a novel protein. The protein was present in the outer membrane as a transmembrane protein and was specifically induced by salt stress, but not by heat shock.

Amino Acid Sequence↗
PubMed2001

Upregulation of histidine decarboxylase mRNA expression in scleroderma skin.

The involvement of histamine in the pathogenesis of systemic sclerosis (SSc) has been suggested. Possible involvement of histamine and histidine decarboxylase (HDC), the synthesizing enzyme for histamine, in the formation of the skin abnormalities in SSc was studied. Skin histamine concentrations in SSc were significantly lower than in normal controls (P < 0.02). In situ hybridization with an HDC probe revealed that the expression of the HDC gene in SSc was greater than in normal controls. The number of cells and the mean grain number per cell expressing HDC mRNA were both significantly greater in SSc than in normal controls (both P < 0.01). These results show a reduction in histamine concentration and an elevated HDC gene expression in SSc skin, indicating an increase in both histamine release and HDC gene expression. The upregulation of histamine turnover appears to be involved in the formation of the skin abnormalities of SSc.

Adult↗
PubMed2001

Quantitative analysis of microchimerism in systemic sclerosis skin tissue.

It has been reported that more male DNA of presumed fetal origin is present in the blood and skin of women with systemic sclerosis (SSc) as compared with healthy controls after delivery, but these findings are controversial. We sought to determine whether male cell DNA is present in SSc using a quantitative polymerase chain reaction for Y chromosome DNA. The study groups comprised 57 healthy women, 49 patients with SSc and 30 patients with connective tissue diseases other than SSc who had given birth to at least one son and/or had experienced fetal loss. The intensity of the PCR bands on negatives of gel photographs was quantified with a video densitometer linked to a computer analysis system. Positive Y chromosome DNA was found in 20 healthy women, 14 SSc patients and 6 patients with connective tissue diseases other than SSc. The occurrence rate of DNA equivalents of male cells among the three groups showed no significant differences. The number of male cell DNA equivalents per 80 ng tissue DNA in SSc patients (4.59+/-9.63), however, was significantly higher than in healthy women (1.83+/-4.96; P < 0.05) and in patients with connective tissue diseases other than SSc (0.27+/-0.64; P < 0.01). The occurrence rate of fetal loss in male cell DNA-positive SSc (eight) was significantly higher than in male cell DNA-negative SSc patients (four; P < 0.01). No correlation was found between the number of male cell DNA equivalents and birth of sons or clinicolaboratory findings. These results indicate that the elevated amount of male cell DNA in SSc skin tissue may contribute to the pathogenesis of SSc.

Adult↗
PubMed2001

Treatment of ruptured undifferentiated sarcoma of the liver in children: a report of two cases and review of the literature.

Undifferentiated (embryonal) sarcoma of the liver (USL) is a highly malignant tumor of early life. Treatment choices for USL, especially with intraperitoneal rupture, are uncertain. Outcomes have been almost uniformly poor until recently. We describe two 7-year-old girls treated for ruptured USL. In the more recent patient, operative biopsy was followed by three cycles of cisplatin (CDDP), adriamycin (ADR), and cyclophosphamide (CPM). A fluid-filled cavity in the tumor showed enlargement and was drained. Two cycles of CDDP, ADR, vincristine (VCR), and ifosfamide were accompanied by reduction in tumor size, and trisegmentectomy was performed. She has no evidence of disease 3.5 years after surgery. In the other patient, left lobectomy was followed by a less intensive regimen, including CPM, VCR, and fluorouracil. This patient died of dissemination within 5 months. In 170 reported pediatric patients with USL, the 2-year disease-free survival was 17%. For the 96 such patients reported since 1980, 2-year disease-free survival had improved to 27%. More aggressive chemotherapy has been associated with this change. Of 8 patients with tumor rupture whose details have been reported (including the 2 present patients) after resection of the tumor, 4 died, 1 was alive with disease, and 3 were free of disease at 8, 49, and 58 months, respectively, after diagnosis. Ruptured USL should be treated with combination chemotherapy including CDDP and ADR, as well as with curative resection.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2001

Fournier's gangrene: report of six cases.

Fournier's gangrene (FG) is a fatal infectious disease with necrotic fasciitis of the external genitalia. This disease persists to this day in spite of recent advances in antibiotics. Although fewer than 100 cases have been reported in Japan, we have treated six cases in the last 4 years. The patients consisted of five men and one woman, with an average age of 47.5 years. All patients received surgical treatment including incisions, aggressive debridement, drainage, irrigation, and antibiotic therapy. Two patients, who suffered from underlying diseases of diabetic nephropathy and inclusion body myositis, died. These findings confirm the fact that FG requires a prompt diagnosis and immediate surgical treatment.

Adult↗
PubMed2001

Postoperative fecoflowmetric analysis in patients with anorectal malformation.

Because conventional methods of evaluating anorectal function do not necessarily provide good correlations between investigative results and symptoms in patients who have undergone surgery for an anorectal malformation (ARM), we recently introduced feco-flowmetry (FFM) to simulate natural anorectal evacuation. The purpose of this study was to embody significant parameters to elucidate the dynamics of anorectal activity on FFM. The parameters of FFM were compared with those of manometry and Kelly's clinical score (KCS) in 24 patients who underwent surgery for an ARM. There were three fecoflow patterns, namely, block (B) type, segmental (S) type, and flat (F) type. The B-type or S-type patterns were seen in patients classified as "clinically good." There were close relationships between the fecoflow pattern and both the operative procedure and the KCS (P = 0.01 and 0.001, respectively). Maximum fecal stream flow rate (Fmax) precisely reflected the tolerance rate of intended normal saline solution in the colorectum (TR), the evacuative rate (ER), and KCS. Fmax > 45 ml/s or TR > 70% or ER > 50% was statistically regarded as the borderline of fecal continence. Thus, the fecoflow pattern might reflect the motor activity of the pelvic floor muscle. FFM provided quantiative and qualitative evaluations concerning anorectal motor activity in patients who had undergone surgery for an ARM.

Adolescent↗
PubMed2001

Photocatalytic degradation of trichloroethylene in water using TiO2 pellets.

A recirculating system of aqueous trichloroethylene (TCE) solutions through the packed bed reactor with TiO2 pellets has been developed in order to mineralize TCE without difficulties for filtration and recovery of catalyst. The TiO2 pellets prepared by sol gel method have photocatalytic activity similar to commercially available PC-101 and PC-102 in the powder form and to ST-B11 pellets. In batch experiments with TiO2 powders, Degussa P-25 is the most active photocatalyst, which indicates that specific surface area is not an important factor controlling the photocatalytic activity in aqueous solutions. The degradation rates of TCE in the recirculating system with TiO2 pellets decreased in the presence of H2O2, while were remarkably accelerated by adding S2O8(2-). The presence of S2O8(2-) ions more than 0.01 mol dm(-3) completely suppressed hole-electron recombination and mineralized 50 ppm TCE with the 2 h irradiation. In a reactor without TiO2 photocatalysts, TCE was photodegraded by SO4- radicals which produced by photodissociation of S2O8(2-). The degradation rates increased with increase of the initial S2O8(2-) concentration. However, TCE was not mineralized but converted to intermediates which were slowly degraded to Cl- by continuing the irradiation.

Catalysis↗
PubMed2001

Microbial-ecological significance of sulfide precipitation within anaerobic granular sludge revealed by micro-electrodes study.

Micro-electrodes were applied to anaerobic granular sludge, which was developed in a UASB reactor, to examine intra-granule profiles with respect to pH, glucose and sulfide. When glucose was employed as a bulk liquid substrate, the micro-electrodes study demonstrated the pH behavior along granule depth: pH decrement at the granule exterior portion due to acid formation (buildup of acidity), and subsequent pH increment at the granule inner portion due to the consumption of acid (buildup of alkalinity). Sulfide micro-electrode proved sulfate reduction that mostly occurred at the granule exterior portion. Chemical equilibrium consideration evidently explained the occurrence of ferric sulfide predominantly in the interior portion, which accounts well for the morphology of a representative double-layered structure of granules grown on a low level of sulfite. Inorganic elements distribution within anaerobic granule was examined by electron probe X-ray micro analysis (EPMA) and ICP methods. The presence of crystalline calcium carbonate (calcite) was identified by X-ray diffraction analysis.

Bacteria, Anaerobic↗
PubMed2001

Intraocular lens subluxation in a patient with facial atopic dermatitis.

A 66-year-old Japanese man presented with subluxation of a posterior chamber intraocular lens (IOL) caused by a rupture of part of Zinn's zonule but no retinal break 2 years after phacoemulsification with IOL implantation. He had a history of atopic dermatitis since infancy. This case presents a rare ocular complication of scratching and rubbing the face and eyelids because of itching related to atopic dermatitis.

Aged↗
PubMed2001

Immunologic self tolerance maintained by T-cell-mediated control of self-reactive T cells: implications for autoimmunity and tumor immunity.

T-cell-mediated dominant control of self-reactive T cells is one mechanism for maintaining immunologic self tolerance. It also hampers the generation of immunity to autologous tumor cells. Abrogation of the control can evoke potent tumor immunity as well as autoimmunity in normal animals. This common regulatory mechanism for autoimmunity and tumor immunity can be exploited to devise a novel immunotherapy against cancer.

Animals↗
PubMed2001

Immunologic tolerance maintained by CD25+ CD4+ regulatory T cells: their common role in controlling autoimmunity, tumor immunity, and transplantation tolerance.

There is accumulating evidence that T-cell-mediated dominant control of self-reactive T-cells contributes to the maintenance of immunologic self-tolerance and its alteration can cause autoimmune disease. Efforts to delineate such a regulatory T-cell population have revealed that CD25+ cells in the CD4+ population in normal naive animals bear the ability to prevent autoimmune disease in vivo and, upon antigenic stimulation, suppress the activation/proliferation of other T cells in vitro. The CD25+ CD4+ regulatory T cells, which are naturally anergic and suppressive, appear to be produced by the normal thymus as a functionally distinct subpopulation of T cells. They play critical roles not only in preventing autoimmunity but also in controlling tumor immunity and transplantation tolerance.

Animals↗
PubMed2001

Comparisons of intraosseous graft healing between the doubled flexor tendon graft and the bone-patellar tendon-bone graft in anterior cruciate ligament reconstruction.

PURPOSE: The purpose of this study was to compare intraosseous graft healing between the doubled flexor tendon (FT) graft and the bone-patellar tendon-bone (BPTB) graft in anterior cruciate ligament (ACL) reconstruction. TYPE OF STUDY: Randomized trial. METHODS: A biomechanical and histologic study was conducted with 24 adult beagle dogs. Bilateral ACL reconstructions were performed in each animal. Autogenous doubled FT and BPTB grafts were used for the left and right knees, respectively. Each end of the 2 grafts was tethered with a polyester suture to a screw post with a washer. The animals were then allowed unrestricted activities in their cages. Eight animals were killed at 3, 6, and 12 weeks, respectively. RESULTS: Histologically, the FT graft was anchored to the tunnel wall with newly formed collagen fibers resembling Sharpey's fibers by 12 weeks. These fibers were more abundant in the anterior (ventral) gap than in the posterior (dorsal) gap. In the BPTB graft, the bone plug was anchored with newly formed bone at 3 weeks, although osteocytes in the plug trabeculae were necrotic for 12 weeks. Degeneration of the tendon-bone junction in the plug progressed at 6 weeks. Tensile testing showed that the weakest site was different not only between the 2 grafts but also between the observation periods. In the FT graft, the weakest site was the graft-wall interface at 3 weeks and the intraosseously grafted tendon at 6 weeks. In the BPTB graft, the weakest site was the graft-wall interface at 3 weeks and the proximal site in the bone plug at 6 weeks. The ultimate failure load of the FT graft was significantly inferior (45.8%) to that of the BPTB graft at 3 weeks (P =.021). At 6 weeks, the load of the FT graft was 85% that of the BPTB graft without a significant difference (P =.395). CONCLUSIONS: As to the clinical relevance, the fixation device chosen for soft-tissue fixation appears to be more important than comparing it to the BPTB graft, although this has yet to be conclusively proven.

Animals↗
PubMed2001

Lack of interaction between bropirimine and 5-fluorouracil on human dihydropyrimidine dehydrogenase.

1. Bropirimine (2-amino-5-bromo-6-phenyl-4-pyrimidinone) is a member of a class of antineoplastic agents that are administered concomitantly or sequentially with anticancer 5-fluorouracil (5-FU) prodrugs in clinical patients. Interactions between bropirimine and 5-fluorouracil (5-FU) were investigated on dihydropyrimidine dehydrogenase (DPD) activity, the rate-limiting enzyme of 5-FU metabolism, in human liver cytosol. Apparent DPD activity was determined by measuring the recovery of [14C]5-FU by HPLC. 2. The apparent activity of 5-FU metabolism (2.1-100 microM) showed a linear relationship in the Eadie-Hofstee plot in the pooled cytosol, suggesting that a single enzyme is responsible for apparent 5-FU metabolism. Km and Vmax were estimated to be 23 microM and 0.32 nmol min(-1) mg(-1) protein, respectively. Apparent DPD activity for 5-FU (25 microM) in the cytosol from 12 individual donors ranged from 0.017 to 0.39 (0.16 +/- 0.12) nmol min(-1) mg(-1) protein, indicating a large intersubject variance. 3. The suicidal inactivators of the DPD enzyme, (E)-5-(2-bromovinyl)uracil and 5-bromouracil (6.3-50 microM), illustrated concentration-dependent inhibition on DPD activity. Isocytosine (6.3-100 microM), used as a negative control, did not affect DPD activity. Bropirimine (6.3-100 microM) also did not show any inhibition of DPD activity. Therefore, bropirimine is unlikely to cause increases in 5-FU levels in clinical patients after co-administration of bropirimine with 5-FU prodrugs.

Adolescent↗
PubMed2001

Probiotics and safety.

Bacterial species that have traditionally been regarded as safe are used in probiotics; the main strains used include lactic acid bacteria and bifidobacteria that inhabit the intestinal tracts of humans and animals. However, reports of frequent isolation of bacteria used in probiotics from infection sources in recent years have raised much debate over the safety of probiotics. This article describes the status quo of isolation of probiotic bacteria from infections and reviews each of the factors that have to be addressed in assessing the safety of probiotics, namely pathogenicity, infectivity, toxicity, and intrinsic properties of the bacteria. Monoassociation with Bifidobacterium longum in gnotobiotic mice as a method to assess safety with respect to infection, and translocation and immune responses as a result of the monoassociation are also described.

Animals↗
PubMed2001

Ab initio structure determination of monoclinic 2,2-dihydroxymethylbutanoic acid from synchrotron radiation powder diffraction data: combined use of direct methods and the Monte Carlo method.

The crystal structure of 2,2-dihydroxymethylbutanoic acid (C(6)H(12)O(4)) in monoclinic form has been determined ab initio from synchrotron radiation powder diffraction data. Two O and five C atoms were first derived by direct methods. Two missing O atoms and one C atom were found by the Monte Carlo method without applying constraint to their relative positions. Positional and isotropic displacement parameters of these non-H atoms were refined by the Rietveld method. Molecules are linked by hydrogen bonds and they make sheet-like networks running parallel to the (010) plane. The Monte Carlo method is demonstrated to be a powerful tool for finding missing atoms in partially solved structure.

Journal Article↗