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T Tsukamoto

Publications and source records attributed to T Tsukamoto.

At least 217 records · Page 12Linked to original sources
PubMed1998

Temperature-sensitive mutation in PEX1 moderates the phenotypes of peroxisome deficiency disorders.

The peroxisome biogenesis disorders (PBDs), including Zellweger syndrome (ZS), neonatal adrenoleukodystrophy (NALD) and infantile Refsum disease (IRD), are autosomal recessive diseases caused by deficiency of peroxisome assembly as well as malfunction of peroxisomes, where >10 genotypes have been reported. ZS patients manifest the most severe clinical and biochemical abnormalities, while those with NALD and IRD show the least severity and the mildest features, respectively. PEX1 is the causative gene for PBDs of complementation group I (CG1), the highest incidence PBD, and encodes the peroxin, Pex1p, a member of the AAA ATPase family. In the present work, we found that peroxisomes were morphologically and biochemically formed at 30 but not 37 degrees C, in the fibroblasts from all CG1 IRD patients examined, whereas almost no peroxisomes were seen in ZS and NALD cells, even at 30 degrees C. A point missense mutation, G843D, was identified in the PEX1 allele of most CG1 IRD patients. The mutant PEX1, termed HsPEX1G843D, gave rise to the same temperature-sensitive phenotype on CG1 CHO cell mutants upon transfection. Collectively, these results demonstrate temperature-sensitive peroxisome assembly to be responsible for the mildness of the clinical features of PEX1 -defective IRD of CG1.

ATPases Associated with Diverse Cellular Activitie↗
PubMed1998

Important microsatellite markers in the investigation of replication errors (RER) in colorectal carcinomas.

BACKGROUND: DNA replication errors (RER) have been found in hereditary nonpolyposis colorectal carcinomas and in sporadic colorectal carcinomas. The incidence of RER depends on which and how many markers are examined. The main purpose of the present study was to determine the key markers for detecting RER most efficiently. METHODS: The RER status of 76 sporadic advanced colorectal carcinomas in the proximal colon were investigated. Seven microsatellite markers (D2S123, D3S1029, D3S1611, D2S72, TP53, Mfd26 and BAT26) were chosen to determine the RER status by PCR using the non-Rl method, because these seven markers have frequently been used in other studies and also detect RER. RESULTS: It was found that 44.7% of sporadic colorectal advanced carcinomas in the proximal colon (34 of 76) showed RER at one or more loci. Among these 34 cases, RER was present at three or more markers (severe RER) in 22. All 22 of these cases showed RER at BAT26 and TP53. The other 12 cases with RER showed RER at one or two markers (mild RER). Eleven of these 12 cases (91%) showed RER at Mfd26 and there were one or two cases with mild RER at each of the other loci. CONCLUSIONS: When one intends to analyze routinely a large number of cases, an analysis of two or three markers (Mfd26 and BAT26 or TP53) is considered to be sufficient for detecting mild and severe RER.

Aged↗
PubMed1998

Detection and long-term existence of Shiga toxin (Stx)-producing Escherichia coli in sheep.

The isolation and characterization of Shiga-like toxin (Stx)-producing Escherichia coli (STEC) from sheep are described. The distribution of stx genes in E. coli isolates was detected by PCR. When brain heart infusion (BHI) broth and novobiocin supplemented m-EC broth (N-mEC) were used as enrichment culture for the isolation of STEC, N-mEC, compared to BHI, showed clearly lower efficiency. Finally, 5 STEC isolates from 4 sheep were isolated and characterized by biochemical and genetical analysis. All of them were confirmed by ELISA and Vero cell cytotoxicity assay for the production of Stx. Moreover, some strains carried hemolysin and eaeA genes and harbored large plasmids. Based on their plasmid profiles, antibiotic patterns and PCR-based DNA fingerprinting analysis using random amplified polymorphic DNA (RAPD), all isolates were different from each other. Three of the isolates were identified to belong to serogroups O2, O153 and O165, respectively, and the STEC strains belonging to these serogroups had been isolated from STEC outbreaks in humans. Four months after the first isolation in July 1997, STEC from sheep #1 was isolated again. A new isolate, HI-11, was identified as STEC O2:Hnt. Simultaneously, 2 STEC, which were genetically and phenotypically different from each other, were isolated from the same sheep at intervals of 4 months. These results demonstrate that sheep may be an important animal for studying human STEC infections, and that further epidemiological surveys on STEC are necessary.

Animals↗
PubMed1998

Detection and genetical characterization of Shiga toxin-producing Escherichia coli from wild deer.

Shiga toxin (Stx)-producing Escherichia coli (STEC) strains isolated from wild deer in Japan were examined. A total of 43 fecal samples were collected 4 times from 4 different sites around Obihiro City, Hokkaido, Japan, in June and July 1997. Seven STEC strains were isolated by PCR screening, all of them were confirmed by ELISA and Vero cell cytotoxicity assay to be producing only active Stx type 2 (Stx2). Moreover, they seemed to carry the hemolysin and eaeA genes of STEC O157:H7, and some isolates harbored large plasmids which were similar to the 90-kilobase virulence plasmid of STEC O157:H7. Based on their plasmid profiles, antibiotic resistance patterns, PCR-based DNA fingerprinting data obtained by using random amplified polymorphic DNA (RAPD) and the stx2 gene sequences, all isolates were divergent from each other except for 3 isolates from the first and second samplings. A DNA sequence analysis of representative isolates revealed that deer originating STEC strains were closely related to each other, but not to the Stx2-producing STEC strains isolated from a mass outbreak in Obihiro at the same time. A phylogenic analysis of the deduced Stx2 amino acid sequences demonstrated that three distinct clusters existed in the deer originating STEC strains and that the Stx of deer originating STEC was closely associated with that originating from humans, but not those of STEC originating from other animals. These results suggest that STEC contamination of deer carcasses should be considered as a potential source of human infection and adequate sanitary inspection of meat for human consumption is also essential for wild animals.

Amino Acid Sequence↗
PubMed1998

Increased expression of sucrase and intestinal-type alkaline phosphatase in human gastric carcinomas with progression.

The activities of sucrase, total alkaline phosphatase (total ALP) and intestinal-type alkaline phosphatase (I-ALP) were assayed in gastric carcinomas and in their surrounding mucosae from 57 patients with advanced cancers, and the localization of sucrase in 203 carcinomas, including 86 early cancers, was examined immunohistochemically using polyclonal anti-sucrase antibody. All three enzymes were active in the 57 carcinomas as well as in their surrounding mucosae, but the levels were fairly low as compared to those in normal jejunum mucosa. A considerable part of the total ALP activity in tumor specimens was assumed to be due to I-ALP itself. Increased sucrase and I-ALP were found with greater depth of invasion by undifferentiated-type carcinomas. The pattern of immunohistochemical localization of sucrase in the 203 carcinomas also clearly indicated increased expression with greater depth of invasion even in differentiated-type carcinomas.

Adenocarcinoma↗
PubMed1998

N-methyl-N-nitrosourea concentration-dependent, rather than total intake-dependent, induction of adenocarcinomas in the glandular stomach of BALB/c mice.

The influence of the level of carcinogen exposure on histopathological types and cellular differentiation of the induced tumors was examined in 100 male BALB/c mice given N-methyl-N-nitrosourea (MNU) in their drinking water at 240 ppm on alternate weeks (total exposure: five weeks) (groups 1), at 120 ppm similarly (total exposure: ten weeks) (group 2), at 60 ppm for 20 weeks continuously (group 3), or at 30 ppm for 40 weeks continuously (group 4). Forty-three differentiated and 17 undifferentiated type adenocarcinomas were induced. Glandular stomach carcinomas and undifferentiated type lesions were more common in mice treated with a high concentration of MNU for a short period than with a low concentration of MNU for a long period, even though total measured intake of MNU was smaller (P < 0.01). All the induced glandular stomach carcinomas, independent of the treatment schedule, consisted entirely of gastric phenotype cells. In conclusion, the induction of glandular stomach cancers and the proportion of undifferentiated type lesion depend not on the total quantity, but rather on the concentration of the carcinogen, while the phenotypic expression of tumor cells in not affected by the differences in the administration protocol.

Adenocarcinoma↗
PubMed1998

Treatment for advanced testicular cancer with high-dose chemotherapy and autologous blood stem cell transplantation.

BACKGROUND: This study was carried out to investigate the efficacy and safety of high-dose chemotherapy (HDC) for the treatment of patients with advanced testicular cancer. METHODS: Seven patients were treated with high-dose carboplatin, etoposide, and ifosfamide followed by autologous blood stem cell transplantation. One patient received 1 cycle, 4 patients received 2 cycles, and 2 patients received 3 cycles of HDC. We performed a total of 15 autologous blood stem cell transplantations: 8 with autologous bone marrow; 6 with peripheral blood stem cells; and 1 with peripheral blood stem cells in addition to autologous bone marrow. RESULTS: Four of the 7 patients achieved a pathologic complete response via early use of HDC and additional salvage surgery. All 4 patients are still alive without evidence of disease at 12, 30, 33, and 54 months, respectively. One patient is alive with active disease at 35 months. Two patients refractory to conventional chemotherapy died of progressive disease at 5 and 27 months, respectively. The hematologic recovery after HDC was rapid, and peripheral blood stem cells tended to have shorter hematologic recovery compared with those from autologous bone marrow, although the difference was not significant. Nonhematologic toxicity was usually mild and manageable. CONCLUSION: High-dose chemotherapy, followed by autologous blood stem cell transplantation, may be safe and effective for patients with advanced testicular cancer, particularly when early use of HDC is conducted for chemotherapy-sensitive patients. A further large, long-term, follow-up study will be needed to define the role of HDC.

Adolescent↗
PubMed1998

Testicular findings, endocrine features and therapeutic responses of men with acquired hypogonadotropic hypogonadism.

BACKGROUND: Men with acquired hypogonadotropic hypogonadism (AHH) who desire restoration of fertility are treated with exogenous gonadotropin. However, gonadotropin (Gn) therapy does not always restore testicular function. It is unknown whether the therapeutic responses to Gn therapy correlate with their testicular histological findings. Thus, we analyzed factors influencing testicular dysfunction and therapeutic responses in AHH. METHODS: Of 21 men with AHH, 11 had no postmeiotic germ cells and were classified as the severe spermatogenic failure group. These were compared with the other 10 patients who had postmeiotic germ cells and comprised the mild spermatogenic failure group. RESULTS: Testicular volume and tubular diameter were significantly smaller, and the basement membrane and tunica propria were significantly thicker in the severe failure group. The gonadotropin basal level and response to exogenous gonadotropin-releasing hormone, and the testosterone response to exogenous human chorionic gonadotropin were significantly lower in the severe failure group of patients. Also, the recovery of spermatogenesis and testosterone secretory potentials was poor in the cases with a duration between diagnosis and treatment of 2 years or more. CONCLUSION: Longer periods without treatment may be responsible for irreversible testicular dysfunction in AHH. Gn therapy should be initiated very soon after the diagnosis of AHH if fertility is desired.

Adult↗
PubMed1998

Metastatic cervical carcinoma mimicking kidney abscess.

A 26-year-old female, who had been treated for cervical carcinoma, presented with high fever and right flank pain. A right renal abscess was initially suspected from the clinical symptoms and diagnostic imaging. However, pathologic findings for the right kidney revealed squamous cell carcinoma, which was consistent in type with the original cervical carcinoma. Demonstration of human papillomavirus 16 in tissues from both the renal tumor and the cervical carcinoma confirmed that the right kidney carcinoma was a metastasis from the cervical carcinoma. The role of interleukin-6 in occurrence of the unexplained fever is discussed.

Abscess↗
PubMed1998

Ileal neobladder for bladder substitution after radical cystectomy.

BACKGROUND: Studer's ileal neobladder is technically simple, and favorable clinical results have been reported. However, there have been only a few follow-up studies on this type of ileal neobladder. We reviewed the clinical outcomes of patients who received Studer's ileal neobladder, with a minor modification, in our institution. METHODS: Twenty-five men underwent bladder reconstruction with Studer's ileal neobladder after radical cystectomy. The function of the ileal neobladder and voiding status were evaluated during follow-up. The follow-up period ranged from 3 to 42 months (mean, 24 months). RESULTS: The ileal neobladder achieved a large capacity at a low basal pressure, associated with a relatively low complication rate directly related to the neobladder. At 12 months after surgery, daytime and nighttime continence rates were 90% and 74%, respectively. In 5 patients who were incontinent, the maximal urethral closure pressure was statistically lower than in patients with continence. CONCLUSION: Studer's ileal neobladder is an easy operative procedure for bladder substitution, and has a relatively low complication rate directly related to the neobladder. Good compliance of the pouch and preservation of the external sphincter mechanism are the most important factors for achieving urinary continence, after construction of the ileal neobladder.

Adult↗
PubMed1998

[Evaluation of commercial kits for a rapid detection of Escherichia coli O157 in stool].

To introduce rapid detection of E. coli O157 in the stool without culturing, nine different commercial kits for detection of E. coli O157 were compared. VIP, Reveal, Path Stik, Quix, Now EH and EZ coli were found to detect E. coli O157 greater than 10(6) CFU/ml. TECRA and Novapath could detect more than 10(5) CFU/ml. VIDAS reacted positive with more than 10(4) CFU/ml. TECRA, Novapath, Quix could detect 1:4, 1:4, 1:9 dilution of stool specimen spiked with E. coli O157 respectively, but others could not detect with 1:9 dilution of stool specimen. When stool specimens spiked with E. coli O157 were diluted ten times, centrifuged slightly and supernatants were tested, Path Stik, Quix and EZ coli could detect 10(7) CFU/ml. TECRA and Novapath could detect 10(6) CFU/ml, whereas VIDAS could detect 10(6) CFU/ml. Quix is therefore one of the most suitable kit for detection of E. coli O157 in the stool at the bedside, although some non-specific reactions were observed. Path Stik is also convenient kit at the bedside. VIDAS, although it requires special equipment, is the most sensitive kit for detection of E. coli O157 and is suitable for detection of low levels of E. coli O157 in the clinical laboratory.

Escherichia coli O157↗
PubMed1998

[Identification of Escherichia coli O157 antigen by polymerase chain reaction].

An assay was developed for the specific detection of Escherichia coli O157 using PCR, because O serological cross-reactivities have been reported between E. coli O157 and some E. coli, other bacterial species. PCR amplification of E. coli O157 rfbE (Ec O157:H7) gene that is necessary for the expression of the O157 antigen, was performed for the identification of E. coli O157. All Shiga toxin-producing Escherichia coli (STEC) O157:H7 and O157:H, non-STEC O157 strains were positive, and other non-O157 E. coli strains were negative by PCR. All tested strains of other bacterial species, like Salmonella O30 and Citrobacter freundii which gave positive results with O157 detection kits, were negative by PCR. It is recommended that PCR amplification of O157 rfbE gene is one of the most specific method for E. coli O157 identification.

Antigens, Bacterial↗
PubMed1998

Peroxisome targeting signal type 1 (PTS1) receptor is involved in import of both PTS1 and PTS2: studies with PEX5-defective CHO cell mutants.

To investigate the mechanisms of peroxisome assembly and the molecular basis of peroxisome assembly disorders, we isolated and characterized a peroxisome-deficient CHO cell mutant, ZP139, which was found to belong to human complementation group II, the same group as that of our earlier mutant, ZP105. These mutants had a phenotypic deficiency in the import of peroxisomal targeting signal type 1 (PTS1) proteins. Amino-terminal extension signal (PTS2)-mediated transport, including that of 3-ketoacyl coenzyme A thiolase, was also defective in ZP105 but not in ZP139. PEX5 cDNA, encoding the PTS1 receptor (PTS1R), was isolated from wild-type CHO-K1 cells. PTS1R's deduced primary sequence comprised 595 amino acids, 7 amino acids less than the human homolog, and contained seven tetratricopeptide repeat (TPR) motifs at the C-terminal region. Chinese hamster PTS1R showed 94, 28, and 24% amino acid identity with PTS1Rs from humans, Pichia pastoris, and Saccharomyces cerevisiae, respectively. A PTS1R isoform (PTS1RL) with 632 amino acid residues was identified in CHO cells; for PTS1R, 37 amino acids were inserted between residues at positions 215 and 216 of a shorter isoform (PTS1RS). Southern blot analysis of CHO cell genomic DNA suggested that these two isoforms are derived from a single gene. Both types of PEX5 complemented impaired import of PTS1 in mutants ZP105 and ZP139. PTS2 import in ZP105 was rescued only by PTS1RL. This finding strongly suggests that PTS1RL is also involved in the transport of PTS2. Mutations in PEX5 were determined by reverse transcription-PCR: a G-to-A transition resulted in one amino acid substitution: Gly298Glu of PTS1RS (G335E of PTS1RL) in ZP105 and Gly485Glu of PTS1RS (G522E of PTS1RL) in ZP139. Both mutations were in the TPR domains (TPR1 and TPR6), suggesting the functional consequence of these domains in protein translocation. The implications of these mutations are discussed.

Amino Acid Sequence↗
PubMed1998

PEX12, the pathogenic gene of group III Zellweger syndrome: cDNA cloning by functional complementation on a CHO cell mutant, patient analysis, and characterization of PEX12p.

Rat PEX12 cDNA was isolated by functional complementation of peroxisome deficiency of a mutant CHO cell line, ZP109 (K. Okumoto, A. Bogaki, K. Tateishi, T. Tsukamoto, T. Osumi, N. Shimozawa, Y. Suzuki, T. Orii, and Y. Fujiki, Exp. Cell Res. 233:11-20, 1997), using a transient transfection assay and an ectopic, readily visible marker, green fluorescent protein. This cDNA encodes a 359-amino-acid membrane protein of peroxisomes with two transmembrane segments and a cysteine-rich zinc finger, the RING motif. A stable transformant of ZP109 with the PEX12 was morphologically and biochemically restored for peroxisome biogenesis. Pex12p was shown by expression of bona fide as well as epitope-tagged Pex12p to expose both N- and C-terminal regions to the cytosol. Fibroblasts derived from patients with the peroxisome deficiency Zellweger syndrome of complementation group III (CG-III) were also complemented for peroxisome biogenesis with PEX12. Two unrelated patients of this group manifesting peroxisome deficiency disorders possessed homozygous, inactivating PEX12 mutations: in one, Arg180Thr by one point mutation, and in the other, deletion of two nucleotides in codons for 291Asn and 292Ser, creating an apparently unchanged codon for Asn and a codon 292 for termination. These results indicate that the gene encoding peroxisome assembly factor Pex12p is a pathogenic gene of CG-III peroxisome deficiency. Moreover, truncation and site mutation studies, including patient PEX12 analysis, demonstrated that the cytoplasmically oriented N- and C-terminal parts of Pex12p are essential for biological function.

Amino Acid Sequence↗
PubMed1998

Effect of the nitric oxide level in the medial preoptic area on male copulatory behavior in rats.

We investigated the influence of the extracellular nitric oxide (NO) level on male copulatory behavior. We confirmed the changes of nitrite (NO2-) and nitrate (NO3-) in the medial preoptic area (MPOA) by administration of the NO precursor L-arginine (L-Arg, 10 mM) or the NO synthase inhibitor NG-monomethyl-L-arginine (L-NMMA, 10 mM) via a dialysis probe. NO2- and NO3- were measured simultaneously by an in vivo microdialysis method coupled with the Griess reaction. L-Arg induced significant elevations of extracellular NO2- and NO3-. L-NMMA significantly reduced NO2- and NO3- levels. We observed male copulatory behavior during infusion of L-Arg or L-NMMA. The mount rate of male rats significantly increased during infusion of L-Arg in the MPOA. Administration of L-NMMA reduced the mount rate. These findings suggested that the elevation of extracellular NO in the MPOA facilitates male copulatory behavior of rats, whereas the decrease of NO reduces their copulatory behavior.

Animals↗
PubMed1998

Lymph node metastasis in patients with carcinomas of the renal pelvis and ureter.

OBJECTIVES: We evaluated the clinical significance of lymph node metastasis in patients with carcinomas of the renal pelvis and ureter. METHODS: 68 patients without distant metastasis were included in this study. Multivariate analysis by Cox's proportional hazards model was applied to detect the prognostic factor(s). RESULTS: 12 patients (17.6%) had nodal involvement. More than 10% of the patients with pT1-2 showed nodal metastasis. Preoperatively determined clinical factors were not a predictive factor for nodal involvement. Nodal metastasis was the only significant negative prognostic factor for patient survival by multivariate analysis. CONCLUSIONS: Lymph node dissection is valuable to predict the clinical outcome of the patients with carcinoma of the renal pelvis and ureter. Attention should be paid to nodal status to select patients for conservative surgery.

Adolescent↗
PubMed1998

Preselected biopsy for normal-appearing mucosa of superficial bladder carcinoma.

OBJECTIVES: We examined the incidence of positive findings (concomitant carcinoma in situ (CIS), frank carcinoma and dysplasia) for normal-appearing mucosal biopsies in superficial bladder carcinoma and the clinical outcome of patients with positive biopsy results. METHODS: Eighty-four cases of newly diagnosed superficial bladder carcinoma, from whom biopsies of preselected cystoscopically normal-appearing mucosal tissue were taken at the time of initial treatment, were studied. Multivariate analysis by Cox's proportional hazards model was applied. RESULTS: Twenty-seven percent of the patients with superficial bladder carcinoma showed positive biopsy results. Positive biopsy results independently influenced intravesical recurrence by Cox's proportional hazards model. CONCLUSIONS: Positive mucosal biopsy results are a significant indicator of intravesical recurrence in patients with superficial bladder carcinoma.

Adult↗