Biomedical subjects

N Suzuki

Publications and source records attributed to N Suzuki.

At least 235 records · Page 13Linked to original sources

PubMed2000

Remarkable axial thiolate ligand effect on the oxidation of hydrocarbons by active intermediate of iron porphyrin and cytochrome P450.

In order to examine the reactivity of active intermediate derived form iron porphyrins, competitive oxidations of alkane and alkene were carried out. It has been proposed that the first step of alkane hydroxylation is H atom abstraction and that of alkene is one-electron transfer. Therefore, it is expected that alkene-alkane competitive oxidation can be used as a probe for discrimination of differences in chemical properties among active species. Cytochrome P450 and SR complex, which is a stable thiolate-ligated iron porphyrin, mediated the oxidation of alkane much more preferentially than iron porphyrin coordinated by imidazole or chloride. These results indicate that thiolate coordination alters the reactivity of the two-electron-oxidized intermediate in a manner that is much more favorable to alkane hydroxylation than the case of chloride or imidazole coordination.

Alkanes↗

PubMed2000

Facilitation of neurotransmitter release at the spiny lobster neuromuscular junction.

Stimulation-induced facilitation of transmitter release was examined at spiny lobster (Palinurus japonicus) neuromuscular junctions by measuring excitatory junctional potentials (EJPs). We found three components of facilitation with the decay time constants about 16, 200 and 1000 ms, respectively. The decay time constants of the nerve terminal free Ca(2+) concentration after stimulation agreed well with the two slower time constants of facilitation. The relationship among the three components of facilitation and a yet slower component, S, was investigated on the basis of several models. The models that have a multiplicative relationship between any two components of facilitation, and the additive model between all components could not account for the results of experiments. Only the 'unified power model', which assumes that facilitation and S are described by the 3-4th power of the sum of underlying components, could account for both the growth process of EJPs during stimulation and the effects of Ca(2+)-chelators. Loading Ca(2+)-chelators, BAPTA and EGTA, into the presynaptic terminals resulted in reduction, but not elimination, of any component of the facilitation. These results suggest that in the spiny lobster neuromuscular junction, the 'unified power model' can describe the relationship between three components of facilitation and S, and that residual free Ca(2+) enhances all three components of facilitation, although it may not be essential for them.

Animals↗

PubMed2000

Suppression of osteoclastic activities by calcitonin in the scales of goldfish (freshwater teleost) and nibbler fish (seawater teleost).

Using a tartrate-resistant acid phosphatase (TRACP) activity, the effects of calcitonin (CT) and estradiol-17beta(E(2)) on osteoclastic activities in cultured scales of goldfish (freshwater fish) and nibbler fish (seawater fish) were examined. In mature male and female goldfish, scales were collected and incubated in Earle's minimun essential medium (MEM) supplemented with either CT (100 ng/ml) or E(2) (100 ng/ml). In both sexes, CT suppressed TRACP activities in the scales, whereas E(2) increased them. When CT (100 ng/ml) and E(2) (100 ng/ml) were added simultaneously to MEM, TRACP activities in the scales did not change as compared with the control. Similar results were obtained with the scales of female nibbler fish. In goldfish, furthermore, the activation of scale TRACP by E(2) was suppressed, depending on CT concentrations (100 pg/ml to 1 microg/ml). In fish reproduction, this function of CT may be useful to protect scales from excess degradation of calcium at vitellogenesis.

Acid Phosphatase↗

PubMed2000

Requirement for Casper (c-FLIP) in regulation of death receptor-induced apoptosis and embryonic development.

Casper (c-FLIP) associates with FADD and caspase-8 in signaling complexes downstream of death receptors like Fas. We generated Casper-deficient mice and cells and noted a duality in the physiological functions of this molecule. casper-/- embryos do not survive past day 10.5 of embryogenesis and exhibit impaired heart development. This phenotype is reminiscent of that reported for FADD-/- and caspase-8-/- embryos. However, unlike FADD-/- and caspase-8-/- cells, casper-/- embryonic fibroblasts are highly sensitive to FasL- or TNF-induced apoptosis and show rapid induction of caspase activities. NF-kappaB and JNK/SAPK activation is intact in TNF-stimulated casper-/- cells. These results suggest that Casper has two distinct roles: to cooperate with FADD and caspase-8 during embryonic development and to mediate cytoprotection against death factor-induced apoptosis.

Animals↗

PubMed2000

Rapid detection of Nocardia amarae in the activated sludge process using enzyme-linked immunosorbent assay (ELISA).

Nocardia amarae, a mycolic acid-containing bacterium, has often been reported to cause foaming of activated sludge in wastewater treatment plants. In this study, the number of N. amarae cells in the activated sludge process was estimated by enzyme-linked immunosorbent assay (ELISA) with anti-N. amarae polyclonal antibody. Use of the antibody enabled N. amarae to be detected at levels of 10(4) to 10(7) colony forming units. On the other hand, the antibody reacted with only a small portion of activated sludge, in which no N. amarae cells were detected by the plate count method. Competitive ELISA was employed to estimate the N. amarae cells in samples taken from a municipal wastewater treatment plant, including raw wastewater and activated sludge foam. The cell numbers estimated by competitive ELISA corresponded well with those obtained by plate counts. Hence, the antibody produced in this study was shown to be effective for the rapid monitoring of N. amarae in the activated sludge process.

Journal Article↗

PubMed2000

Identification of tamoxifen-DNA adducts induced by alpha-acetoxy-N-desmethyltamoxifen.

Treatment with tamoxifen increased the risk of endometrial cancers in breast cancer patients and women participating in the chemoprevention study. In our laboratory, tamoxifen-DNA adducts, including alpha-(N(2)-deoxyguanosinyl)tamoxifen (dG-N(2)-TAM), were detected in the endometrium of women taking tamoxifen [Shibutani, S., et al. (1999) Chem. Res. Toxicol. 12, 646-653]. On the basis of recent animal studies, deoxyguanosinyl-N-desmethyltamoxifen (dG-N-desmethylTAM) adducts are also suspected to be formed in the liver. In the study presented here, we synthesized alpha-acetoxy-N-desmethyltamoxifen as a model activated metabolite of N-desmethyltamoxifen. The overall yield of alpha-acetoxy-N-desmethyltamoxifen from alpha-hydroxytamoxifen was approximately 42%. alpha-Acetoxy-N-desmethyltamoxifen was highly reactive to 2'-deoxyguanosine, as was similarly observed for tamoxifen alpha-sulfate. The two reaction products were identified as a mixture of epimers of the trans form or cis form of alpha-(N(2)-deoxyguanosinyl)-N-desmethyltamoxifen (dG-N(2)-N-desmethylTAM) by mass and proton magnetic resonance spectroscopy. In addition, the trans and cis forms of dG 3'-monophosphate-N(2)-N-desmethylTAM were prepared as standard markers for (32)P-postlabeling/HPLC analysis. Using this technique, dG-N(2)-N-desmethylTAM adducts were detected in calf thymus DNA reacted with alpha-acetoxy-N-desmethyltamoxifen.

Animals↗

PubMed2000

Contribution of TNF-alpha and IL-10 gene polymorphisms to graft-versus-host disease following allo-hematopoietic stem cell transplantation.

Some cytokines are believed to play a role in the development of acute and chronic GVHD after allo-hematopoietic stem cell transplantation. It has been reported that TNF-alpha and IL-10 gene polymorphisms are associated with the production of those cytokines and the development of graft failure after organ transplantation and systemic lupus erythematosus. We examined whether TNF-alpha and IL-10 gene polymorphisms affect the severity of acute GVHD (aGVHD) and chronic GVHD (cGVHD). Sixty-two and 54 patients were available for the analysis of aGVHD and cGVHD, respectively. We analyzed the gene polymorphisms derived from pre- and post-transplant blood cells. Donor-derived TNF2 allele (A) was more frequently detected in patients with aGVHD III/IV than those aGVHD 0-II (2/6 vs 2/56) (P = 0.04). The donors of the patients with cGVHD more frequently possessed a greater number of alleles (allele 13 or more which contain 26 or more CA repeats) in IL-10.G than those without (13/26 vs 5/28) (P = 0.02), and the patients with cGVHD had more CA repeats in donor-derived IL-10.G than those without (mean = 25.2 vs 23.4) (P = 0.01). Donor-derived TNF-308 and IL-10.G alleles may contribute to severe aGVHD and cGVHD, respectively, and will help us distinguish those patients at high risk for GVHD.

Acute Disease↗

PubMed2000

Increase in ultraviolet sensitivity by overexpression of calpastatin in ultraviolet-resistant UVr-1 cells derived from ultraviolet-sensitive human RSa cells.

Human RSa cells are highly sensitive to apoptotic-like cell death by ultraviolet irradiation (UV) while UVr-1 cells are their variant with an increased resistance to UV. Three days after UV at 10 J/m2, the viability of RSa cells was approximately 17% while that of UVr-1 cells was 65%. This different survival might reflect apoptotic cell death since apoptosis-specific DNA ladder was more clearly observed in RSa cells than in UVr-1 cells after UV. Addition of ALLN/calpain inhibitor I to the culture medium after UV resulted in similar survival (14 - 18%) between RSa and UVr-1 cells. Immunoblot analysis showed down-regulation of protein kinase CTheta, Src, Bax and mu-calpain after UV was more prominent in UVr-1 than in RSa cells. Activated mu-calpain appeared within 1 h post-UV only in UVr-1 cells. The expression of calpastatin, a specific endogenous inhibitor of calpain, was higher in RSa than in UVr-1 cells. To further examine the role of calpain in UV-induced cell death, cDNA of human calpastatin was transfected into UVr-1 cells. The results showed that overexpression of calpastatin suppressed down-regulation of Src, mu-calpain and Bax. Concomitantly, colony survival after UV was reduced in calpastatin-transfected cells as compared to vector control cells. Our results suggest that activation of calpain might account for, at least in part, the lower susceptibility to UV-induced cell death in UVr-1 cells.

Apoptosis↗

PubMed2000

Changes in absorptive function of rat intestine injured by methotrexate.

1. Methotrexate (MTX), an anticancer drug, has been shown to induce acute injury in the small intestine. The present study was designed to investigate the in vivo absorptive function of the small intestine injured by MTX using an amino-beta-lactam antibiotic cephalexin (CEX). Time-dependent changes in diamine oxidase (DAO) and alkaline phosphatase (ALP) activity in the small intestine and histopathological findings were also measured in rats treated with MTX (20 mg/kg). 2. Most severe mucosal damage was observed 2 days after MTX treatment and the area under the plasma concentration-time curve of CEX (AUC(CEX)) following oral administration of 20 mg/kg tended to decrease. Thereafter, the AUC(CEX) increased significantly and the histopathological changes diminished within 5 days. 3. Both villus height and mucosal weight followed the same pattern, decreasing in the first 2 or 3 days following treatment, increasing on the 5th day and returning to control levels by the 10th day. Methotrexate-induced changes in the mucosal wet weight/whole intestinal weight ratio were significantly correlated with those of AUC(CEX), but did not correlate with mucosal DAO and ALP activity. 4. These findings provide evidence that the change in the total amount of CEX is an index of the active transport function, probably by intestinal peptide transporter (PEPT1), and is well reflected by histopathological changes in the intestinal mucosa induced by MTX. In addition, there is a possibility that this method could be applied in the clinical setting for diagnosis of intestinal status and absorptive function.

Alkaline Phosphatase↗

PubMed2000

Oesophageal cavernous haemangioma diagnosed histologically, not by endoscopic procedures.

Haemangioma of the oesophagus is uncommon in patients with benign oesophageal tumours. We present a patient with an oesophageal haemangioma detected during mass screening of the upper gastrointestinal tract. The patient, a 59-year-old man, had neither abdominal complaints nor a history of gastrointestinal diseases. Endoscopic examination revealed a blue-coloured submucosal tumour (approximately 3 cm in diameter) at the middle portion of oesophagus. Endoscopic Doppler ultrasonography showed an homogeneous and hypoechoic mass without blood flow in the submucosal layer of the oesophagus. However, a magnetic resonance imaging scan did not give a typical image for oesophageal haemangioma. Therefore, partial resection of the tumour was performed to obtain a differential diagnosis using the procedures of endoscopic ligation and polypectomy. Histological examination of the resected tissue showed a cavernous haemangioma in the oesophagus. This endoscopic technique may be useful for the differential diagnosis of oesophageal haemangioma.

Diagnostic Imaging↗

PubMed2000

Seizure recurrence after reduction of an antiepileptic drug in patients with unprovoked seizures and severe neurological abnormalities.

A prospective study of antiepileptic drug (AED) reduction in patients with unprovoked seizures and severe neurological abnormalities after a seizure-free period of more than 5 years was performed. From a hospital for severely handicapped children (150 patients) and an institution for mentally handicapped people (89 persons), 13 patients were enrolled to this study after informed consent was obtained. All patients had experienced a seizure-free period of more than 7 years (median, 10 years). The patients had IQs of less than 50 and were almost dependent in their life. Five patients had additional motor deficits. The patients had been taking one to three AED (mean, 1.9) before reduction and only one AED was withdrawn. During the following 2years, four of the 13 patients (31%) showed a recurrence of seizures. The age at the time of the last seizure was lower in the seizure-free patients. As to the 10 patients with onset ages of 10 or less, a significant factor as to seizure recurrence was whether or not seizures were controlled before the age of 11 years (P < 0.05, Fisher's exact probability test). It is suggested that a patient with severe neurological abnormalities, in whom epilepsy or unprovoked seizures are controlled before the age of 11 years (i.e. before adolescence) could be a candidate for the reduction of AED.

Adolescent↗

PubMed2000

Change in the ratio of free-to-total prostate-specific antigen during progression of advanced prostate cancer.

BACKGROUND: The ratio of free-to-total prostate-specific antigen (PSA) is different in benign prostatic hyperplasia and in the early stage of prostate cancer. The present study was undertaken to examine the ratio of free-to-total PSA in the advanced stage of this cancer and its subsequent change during course of the disease. METHODS: Free and total PSA were measured in sera collected from the following patients with benign and cancerous prostatic diseases: 47 cases of benign prostatic hypertrophy, nine in TIC with less than 10 ng/mL of total PSA, 11 in stage C, 16 in D2, 22 in remission under endocrine therapy, and 12 in relapse. In addition, PSA was measured sequentially in four other patients who were also in relapse. RESULTS: The ratio of free-to-total PSA was similar in early and advanced stages of untreated prostate cancer and was lower than that in benign prostatic hyperplasia. The ratio increased to the level of benign prostatic hyperplasia during remission from stages C and D2 under endocrine therapy. There was no correlation with the intervals from the start of the therapy to examination. Following relapse, the ratio came down gradually to the level obtained in untreated prostate cancer. CONCLUSION: The ratio of free-to-total PSA was similar in all stages of untreated prostate cancer. Response and relapse to endocrine therapy were associated with increase and decrease in ratio, respectively.

Disease Progression↗

PubMed2000

Risk of contralateral manifestation in children with unilateral inguinal hernia: should hernia in children be treated contralaterally?

PURPOSE: This study was done to identify risk factors for metachronous manifestation of contralateral inguinal hernia in patients with unilateral inguinal hernia. METHODS: Characteristics of 156 patients with metachronous contralateral hernia were compared with those of 156 patients with unilateral hernia who were ascertained not to have presented with contralateral hernia. RESULTS: There was a tendency for the hernia to be more often on the left side in 88 of 156 patients (56.4%) with contralateral manifestation compared with 70 of 156 patients (44.9%) in the control group (P =.054). The age at hernia repair of the patients with contralateral manifestation, 1 to 120 months (median, 14 months), was significantly younger than the 1 to 149 months (median, 20 months) of the control patients (P =.016). More patients with contralateral manifestation had a family history of inguinal hernia, and the percentage, 24.4%, was significantly higher than the 14.7% in the control group (P =.046). A univariate analysis with the Cox regression models found that hernia on the left side and a positive family history were significantly associated with the metachronous manifestation of contralateral hernia (hazard ratio [HR], 1.40; P =. 037 and HR, 1.59; P =.013, respectively). CONCLUSION: The risk of metachronous manifestation of contralateral hernia is high in patients with left-side hernia and in those with a family history, and the incidence of contralateral hernia is at most 10% in these patients. The authors think that the incidence is still too low to justify routine exploration and surgery for a patent processus vaginalis. Contralateral exploration should therefore be reserved for high-risk patients in whom second anesthesia and surgery have to be avoided.

Adolescent↗

PubMed2000

Increased expression of S100A6 at the invading fronts of the primary lesion and liver metastasis in patients with colorectal adenocarcinoma.

Two members of the S100 gene family, S100A6 and S100A4 have been suggested to be associated with cancer invasion and metastasis. To study their involvement in the malignancy of human colorectal adenocarcinoma, we examined the protein expression levels of S100A6 and S100A4 in the primary colorectal adenocarcinoma (T) and paired adjacent normal colorectal mucosa (N) from 12 cases, quantitatively by Western blot analysis. In 11 of 12 and seven of 12 cases, S100A6 and S100A4 expression levels were higher in T than in N, respectively. Average S100A6 level in T was significantly higher than in N (about x 2.3;P = 0.001), whereas average S100A4 level in T was not. When S100A6 expression levels in three sets of matched samples of primary colorectal adenocarcinoma (T) and liver metastasis (M) were examined, S100A6 levels were higher in M than in T in two of three cases. Immunohistochemical analysis using monoclonal anti-S100A6 antibody showed that 23 of 42 (55%) primary colorectal adenocarcinoma and 15 of 16 (94%) liver metastasis specimens were positively stained. S100A6 immunostaining of primary colorectal adenocarcinomas was significantly more intense in the invading fronts with structural atypia than in central portions with glandular structure (P< 0.0001), whereas Ki-67 staining (a growth marker) was similar in these two portions. Interestingly, S100A6 and Ki-67 immunostaining patterns in liver metastases were also the same as in primary lesions. These results suggest that S100A6 is involved in the invasive process of human colorectal adenocarcinomas and that S100A6 expression levels decrease when carcinoma cells form glandular structure again at the central portions of metastatic nodules.

Adenocarcinoma↗

PubMed2000

A detailed linkage map of medaka, Oryzias latipes: comparative genomics and genome evolution.

We mapped 633 markers (488 AFLPs, 28 RAPDs, 34 IRSs, 75 ESTs, 4 STSs, and 4 phenotypic markers) for the Medaka Oryzias latipes, a teleost fish of the order Beloniformes. Linkage was determined using a reference typing DNA panel from 39 cell lines derived from backcross progeny. This panel provided unlimited DNA for the accumulation of mapping data. The total map length of Medaka was 1354.5 cM and 24 linkage groups were detected, corresponding to the haploid chromosome number of the organism. Thirteen to 49 markers for each linkage group were obtained. Conserved synteny between Medaka and zebrafish was observed for 2 independent linkage groups. Unlike zebrafish, however, the Medaka linkage map showed obvious restriction of recombination on the linkage group containing the male-determining region (Y) locus compared to the autosomal chromosomes.

Animals↗

PubMed2000

Simultaneous development of a pineal tumor and an intradural spinal mass during remission of acute lymphocytic leukemia.

A small percentage of children with acute lymphocytic leukemia experience relapse in the central nervous system in spite of prophylaxis. Diffuse leptomeningeal infiltration is common but an intracranial leukemic mass or spinal cord involvement is a rare manifestation. We report a child with acute lymphocytic leukemia who simultaneously developed a pineal tumor and an intradural spinal cord mass as her first relapse. She was successfully managed by comprehensive combined treatment including peripheral blood stem cell transplantation. She remains in continuous complete remission for more than 5 years without further evidence of neurological sequelae.

Child, Preschool↗

PubMed2000

Phorbol ester-potentiated liposomal transfection to monocytic PLB-985 cells.

In order to improve transient gene transfer into PLB-985 cells, we treated cells with 12-tetradecanoylphorbol 13-acetate (TPA) 4 h before transfection, and increased by 540-fold the reporter activity of the firefly luciferase gene transfected by TFL-01, a cationic liposome. Dioctanolyglycerol added before TPA addition inhibited the TPA-dependent increase in activity, suggesting it to be a TPA competitor for PKC binding. H7, staurosporine, GO 6976, and H8, but not GF 109203X and forskolin, inhibited the TPA-dependent increase in reporter activity when added 8 h after TFL-01/gene addition. Forskolin and GF 109203X also inhibited the increase when added before TPA. Therefore, for the potentiation of transfection by the TPA/TFL-01 method, conventional PKC activity with significant but low protein kinase A (PKA) activity are first required, and then a novel PKC activity with significant PKA activity. TPA enhanced the uptake of FITC-labeled phosphorothioated oligonucleotides and their prolonged maintenance by cells, suggesting increased TFL-01-assisted plasmid uptake and its stabilization in TPA-treated PLB-985 cells. This method was used successfully for the sensitive analysis of the promoter function of the gp91(phox) gene, implying the method to be generally useful for promoter analyses of various genes expressed in differentiated human monocytic cells.

Amino Acid Sequence↗

PubMed2000

Increased expression after X-irradiation of MUC1 in cultured human colon carcinoma HT-29 cells.

The effect of X-irradiation on production of MUC1 was studied with human colon carcinoma HT-29 cells. As evaluated by immunocytochemical staining, the percentages of MUC1-positive cells in cells at 4 days after 6 Gy irradiation and in unirradiated control cells were 52 +/- 3.5% (n = 6) and 26 +/- 2.8% (n = 6), respectively. Flow-cytometric analysis of living cells showed that MUC1 began to rise from day 1, reaching a plateau by day 4 after 6 Gy irradiation. Western blot analysis with monoclonal antibody MY.1E12 against glycosylated MUC1 (mature form) showed dose-dependent increases of two bands (500 and 390 kDa) corresponding to two polymorphic MUC1 alleles. Premature forms of MUC1 (350 and 240 kDa) were detectable with monoclonal antibody HMFG-2 only in irradiated cells, suggesting that new core protein synthesis had been induced. The transcriptional activity of the MUC1 gene was analyzed in terms of transient expression of MUC1-CAT reporter plasmids containing 5'-flanking sequences of the MUC1 gene fused to the bacterial chloramphenicol acetyltransferase (CAT) gene. The results of CAT assay indicate that enhanced expression of MUC1 in irradiated HT-29 cells was due to upregulation of MUC1 transcription, and required the upstream promoter.

Antibodies, Monoclonal↗