Search PubMed⌕ Search

Biomedical subjects

T Tsukamoto

Publications and source records attributed to T Tsukamoto.

At least 163 records · Page 9Linked to original sources
PubMed1999

Nonsense and temperature-sensitive mutations in PEX13 are the cause of complementation group H of peroxisome biogenesis disorders.

Peroxisome biogenesis disorders, including Zellweger syndrome (ZS), neonatal adrenoleukodystrophy (NALD) and infantile Refsum disease, are lethal hereditary diseases caused by abnormalities in peroxisomal assembly. To date, 12 genotypes have been identified. We now have evidence that the complete human cDNA encoding Pex13p, an SH3 protein of a docking factor for the peroxisome targeting signal 1 receptor (Pex5p), rescues peroxisomal matrix protein import and its assembly in fibroblasts from PBD patients of complementation group H. In addition, we detected mutations on the human PEX13 cDNA in two patients of group H. A severe phenotype of a ZS patient (H-02) was homozygous for a nonsense mutation, W234ter, which results in the loss of not only the SH3 domain but also the putative transmembrane domain of Pex13p. A more mildly affected NALD patient (H-01), whose fibroblasts showed the temperature-sensitive (TS) phenotype, was homozygous for a missense mutation in the SH3 domain of Pex13p, I326T. This mutant PEX13 cDNA expression in a PEX13-defective CHO mutant showed I326T to be a TS mutation and thus suggested that Pex13p with the I326T mutation in the SH3 domain is stable at 30 degrees C but is somewhat unstable at 37 degrees C.

Amino Acid Sequence↗
PubMed1999

Relationship between multicentric occurrence of hepatocellular carcinoma and histology of noncancerous hepatic tissue in patients with chronic hepatitis C.

The relationship between multicentric occurrence of hepatocellular carcinoma (HCC) and the histology of noncancerous hepatic tissue was investigated in 252 patients infected with hepatitis C virus (HCV) and surgically treated for HCC. One type of multicentric HCC had at least one tumor consisting of well-differentiated HCC, together with moderately or poorly differentiated HCC located in a separate region. The other type had an area of well-differentiated component around HCC with less differentiation in all occurrences. Noncancerous hepatic tissues were assessed using a histologic activity index score. Serum alanine aminotransferase (ALT) activity, the concentration of type 4 collagen, the grading score (severity of active hepatitis), and the staging score (degree of fibrosis) were significantly higher in patients with multicentric HCCs than in those without them. Platelet count was significantly lower in patients with multicentric HCCs. The prevalence of multicentric HCCs increased as the grading score and staging score increased. On univariate analysis, a low platelet count and high grading and staging scores were risk factors for multicentric HCCs. A high ALT activity and a high concentration of type 4 collagen tended to be risk factors. On multivariate analysis, high grading score and high staging score were independent risk factors. These findings indicate that active hepatitis and extensive fibrosis are responsible for the development of multicentric HCCs. Measurement of platelet count, ALT activity, and the concentration of type 4 collagen, and histologic assessment of noncancerous hepatic tissue provide information useful for estimation of the potential for multicentric carcinogenesis.

Alanine Transaminase↗
PubMed1999

Effects of continuous hepatitis with persistent hepatitis C viremia on outcome after resection of hepatocellular carcinoma.

The effect of persistent hepatitis C viremia on the outcome after resection of hepatocellular carcinoma (HCC) was investigated in 59 consecutive patients with a single small HCC (< or = 3.0 cm in diameter). The presence of serum hepatitis C virus (HCV) RNA was evaluated using a reverse transcription polymerase chain reaction method as well as a branched DNA probe method. Clinicopathologic findings were compared between patients with and without viremia and the risk factors for poor outcome were evaluated. Hepatitis C virus (HCV) RNA was not detected in the sera from 7 patients (group 1), but was detected in the sera from the other 52 patients (group 2). Alanine aminotransferase (ALT) activity was significantly higher in group 2 than in group 1. The proportion of patients with active hepatitis was significantly higher in group 2. In group 2, new HCC often developed after the operation and four patients died of liver dysfunction. HCV viremia, high ALT activity, high concentration of total bilirubin, and liver cirrhosis were related to recurrence after the operation. Multivariate analysis indicated that HCV viremia and high ALT activity were independent risk factors for recurrence of HCC. Continuous hepatitis with persistent HCV viremia worsened the outcome after the resection of HCC by causing new development of HCC and deterioration of liver function. In patients with HCV-related HCC, but without HCV viremia, satisfactory results can be expected after liver resection.

Aged↗
PubMed1999

Development and distribution of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP)-induced aberrant crypt foci in the rat large intestine.

Aberrant crypt foci (ACF) are generally considered to be preneoplastic lesions for colon cancer. To assess their induction by 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), a colon carcinogen, we performed a sequential study of ACF morphology and localization. F344 male rats were given PhIP, and methylene blue-stained colon epithelium and isolated crypts were analyzed at weeks 12, 25, 50, and 75. Each crypt was classified into 2 groups, "single" with round bottoms and "bifurcating" displaying V-shaped clefts (indicating proliferation). In combination with the number of crypts in an ACF, this classification was a good indicator for the generation of ACF in line with the fission mechanism of growth. Increasing numbers of crypts in ACF through weeks 12 to 75 and decreased percentages of ACF with bifurcating crypts at the late time points indicated that proliferation of crypts occurs predominantly during the early stages. The distribution pattern showed a significant shift (P < 0.000005) from the distal to the proximal part of the large intestine between weeks 25 and 50. Adenocarcinomas were first found to develop at week 50 in the ascending colon and cecum where bifurcating crypts were generally lacking at weeks 12 and 25. These data suggest the existence of (1) proliferating ACF which contains bifurcating crypt(s) and (2) quiescent or senescent ACF which consists of only single crypts.

Animals↗
PubMed1999

Blockade of NAALADase: a novel neuroprotective strategy based on limiting glutamate and elevating NAAG.

Excessive glutamate receptor activation is thought to be involved in the neuronal injury caused by stroke. Based on the hypothesis that N-acetyl-aspartyl-glutamate (NAAG) is a modulatory neurotransmitter or storage form of glutamate, we have pursued a novel strategy of therapeutic intervention, blockade of N-acetylated alpha-linked acidic dipeptidase (NAALADase), the enzyme that hydrolyzes NAAG to liberate glutamate. Using the suture model of transient middle cerebral artery occlusion (MCAO) in rats, the prototype NAALADase inhibitor 2-(phosphonomethyl)pentanedioic acid (2-PMPA) dramatically reduced extracellular glutamate accumulation measured by microdialysis both during a 2-hour occlusion and during reperfusion, consistent with an effect on glutamate supply. During reperfusion, the decrease in glutamate was accompanied by an equimolar, reciprocal rise in extracellular NAAG. NAALADase inhibition may prove to be a well tolerated therapy for cerebral ischemia. In addition, NAALADase inhibitors should prove to be important tools in understanding the physiological role of NAAG in the brain.

Animals↗
PubMed1999

[Background factors and clinical course of patients with urosepsis].

In this study, we analyzed background factors and clinical courses of 31 patients having 32 episodes of urosepsis, which was defined as the disease when the same species of bacteria were simultaneously isolated both from urine and blood in a febrile (> or = 38 degrees C) patient. Most of the patients had a malignant disease. These patients were classified into 3 groups by febrile patterns, based on [responder], [partial responder] and [non-responder], [non-responder] was one in which fever persisted for more than 7 days. Background factors such as those of bacteria and host were compared among the three groups. Pseudomonas aeruginosa was more frequently isolated from both urine and blood of patients having not only the [responder] but also the [non-responder]. Patients having the [responder] and [partial responder] had a higher frequency of isolation of Escherichia coli (E. coli) from urine and blood, suggesting that urosepsis caused by E. coli may respond more easily to antimicrobial chemotherapy. While the direct cause of urosepsis was not identified in 6 patients, manipulations of the urinary tract were a direct cause of the disease in all 26 other patients. An indwelling catheter in the central vein or urinary tract alone did not influence the clinical courses of patients. However, when patients with respiratory or renal dysfunction, or a cerebrovascular accident had an indwelling catheter, the urosepsis was intractable for antibacterial chemotherapy. Antimicrobial chemotherapy using a single agent was effective in all patients having the [responder]. Combination chemotherapy or alternation of agents was eventually needed for treatment in more than half of the patients with the [partial responder] or [non-responder]. No patients died from the disease.

Adult↗
PubMed1999

Defective PEX gene products correlate with the protein import, biochemical abnormalities, and phenotypic heterogeneity in peroxisome biogenesis disorders.

Peroxisome biogenesis disorders (PBD) comprise three phenotypes including Zellweger syndrome (ZS) (the most severe), neonatal adrenoleucodystrophy, and infantile Refsum disease (IRD) (the most mild), and can be classified into at least 12 genetic complementation groups, which are not predictive of the phenotypes. Several pathogenic genes for PBD groups have been identified, but the relationship between the defective gene products and phenotypic heterogeneity has remained unclear. We identified a mutation in the PEX2 gene in an IRD patient with compound heterozygosity for a missense mutation and the known nonsense mutation detected in ZS patients. In transfection experiments using the peroxisome deficient CHO mutant, Z65 with a nonsense mutation in the PEX2 gene, we noted the E55K mutation had mosaic activities of peroxisomal protein import machinery and residual activities of peroxisomal functions, including dihydroxyacetone phosphate acyltransferase and beta oxidation of very long chain fatty acids. The nonsense mutation severely affects these peroxisomal functions as well as the protein import. These data suggest that allelic heterogeneity of the PEX gene affects the peroxisomal protein import and functions and regulates the clinical severity in PBD.

Catalase↗
PubMed1999

Role of tyrosine phosphorylation in the reassembly of occludin and other tight junction proteins.

After the simulation of anoxia by ATP depletion of MDCK cell monolayers with metabolic inhibitors, the tight junction (TJ) is known to become structurally perturbed, leading to loss of the permeability barrier. Peripheral TJ proteins such as zonula occludens 1 (ZO-1), ZO-2, and cingulin become extremely insoluble and associate into large macromolecular complexes (T. Tsukamoto and S. K. Nigam. J. Biol. Chem. 272: 16133-16139, 1997). For up to 3 h, this process is reversible by ATP repletion. We now show that the reassembly process depends on tyrosine phosphorylation. Recovery of transepithelial electrical resistance in ATP-replete monolayers was markedly inhibited by the tyrosine kinase inhibitor, genistein. Indirect immunofluorescence revealed a decrease in staining of occludin, a membrane component of the TJ, in the region of the TJ after ATP depletion, which reversed after ATP repletion; this reversal process was inhibited by genistein. Examination of the Triton X-100 solubilities of occludin and several nonmembrane TJ proteins revealed a shift of occludin and nonmembrane TJ proteins into an insoluble pool following ATP depletion. These changes reversed after ATP repletion, and the movement of insoluble occludin, ZO-1, and ZO-2 back into the soluble pool was again via a genistein-sensitive mechanism. Rate-zonal centrifugation analyses of detergent-soluble TJ proteins showed a reversible increase in higher density fractions following ATP depletion-repletion, although this change was not affected by genistein. In 32P-labeled cells, dephosphorylation of all studied TJ proteins was observed during ATP depletion, followed by rephosphorylation during ATP repletion; rephosphorylation of occludin was inhibited by genistein. Furthermore, during the ATP repletion phase, tyrosine phosphorylation of Triton X-100-insoluble occludin, which is localized at the junction, as well as ZO-2, p130/ZO-3 (though not ZO-1), and other proteins was evident; this tyrosine phosphorylation was completely inhibited by genistein. This indicates that tyrosine kinase activity is necessary for TJ reassembly during ATP repletion and suggests an important role for the tyrosine phosphorylation of occludin, ZO-2, p130/ZO-3, and possibly other proteins in the processes involved in TJ (re)formation.

Adenosine Triphosphate↗
PubMed1999

A role for intracellular calcium in tight junction reassembly after ATP depletion-repletion.

The integrity of the tight junction (TJ), which is responsible for the permeability barrier of the polarized epithelium, is disrupted during ischemic injury and must be reestablished for recovery. Recently, with the use of an ATP depletion-repletion model for ischemia and reperfusion injury in Madin-Darby canine kidney cells, TJ proteins such as zonula occludens-1 (ZO-1) were shown to reversibly form large complexes and associate with cytoskeletal proteins (T. Tsukamoto and S. K. Nigam, J. Biol. Chem. 272: 16133-16139, 1997). In this study, we examined the role of intracellular calcium in TJ reassembly after ATP depletion-repletion by employing the cell-permeant calcium chelator 1, 2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid-AM (BAPTA-AM). Lowering intracellular calcium during ATP depletion is associated with significant inhibition of the reestablishment of the permeability barrier following ATP repletion as measured by transepithelial electrical resistance and mannitol flux, marked alterations in the subcellular localization of occludin by immunofluorescent analysis, and decreased solubility of ZO-1 and other TJ proteins by Triton X-100 extraction assay, suggesting that lowering intracellular calcium potentiates the interaction of TJ proteins with the cytoskeleton. Coimmunoprecipitation studies indicated that decreased solubility may partly result from the stabilization of large TJ protein-containing complexes with fodrin. Although ionic detergents (SDS and deoxycholate) appeared to cause a dissociation of ZO-1-containing complexes from the cytoskeleton, sucrose gradient analyses of the solubilized proteins suggested that calcium chelation leads to self-association of these complexes. Together, these results raise the possibility that intracellular calcium plays an important facilitatory role in the reassembly of the TJ damaged by ischemic insults. Calcium appears to be necessary for the dissociation of TJ-cytoskeletal complexes, thus permitting functional TJ reassembly and paracellular permeability barrier recovery.

Adenosine Triphosphate↗
PubMed1999

[Development and assessment of the pharmaceutical management and guidance services for inpatients considering clinical value and economy].

We developed pharmaceutical management and guidance services for inpatients in a ward of circulatory medicine, considering clinical and economical standpoints. In these services, pharmacists deliver drugs prescribed for inpatients with individual drug information papers, explain to them about their drugs using information papers and give counsel. Since most of the patients were aged people, developing many kinds of diseases and taking many kinds of drugs, they had many problems such as lack of knowledge of the effects of drugs. First, we surveyed views of patients, physicians and nurses on these services. Consequently, all of them advised us that "pharmacists should explain to patients about the prescribed drugs using information papers." The patients preferred pharmacists as expositors of drugs to physicians or nurses. The physicians considered that "pharmacists have to attach importance to clinical information and package-inserts of drugs and explain to patients about drug information using pamphlet in response to the understanding of patients." The nurses wanted to cooperate with pharmacists in "improving medication compliance." On the basis of these views, we improved our services. Next, we made a survey of patients' knowledge about their drugs. We found that in the patients the level of knowledge concerning "ways," "effects" and "reasons" of taking drugs and that of "compliance" and "satisfaction in taking drugs" were improved through these services. The patients reentered in the hospital kept a high level. The ratio of patients taking drugs by themselves increased. Last, we also applied this method to wards of "blood and collagen diseases" and "pediatrics." The demand for these services increased smoothly. We compared these services based on our method with all other services by hospital pharmacists from the viewpoint of economy. We found that only our service method was beneficial.

Drug Therapy↗
PubMed1999

Serotypes and virulence factors of Escherichia coli strains isolated from dogs and cats.

E. coli strains isolated from urine of dogs and cats with urinary tract infections (UTI) and from feces of healthy one's were serotyped, and the serotypes were correlated with uropathogenic virulence factors. The most prevalent O-serotypes, O4 and O6, were isolated from dogs and cats with UTI. In contrast, O11 and O102 strains were the most frequently found from feces of healthy dogs and cats. Most of type O4 and O6 strains possessed such virulence factors as pil, pap, sfa, hly, and cnf1, while most type O11 and O102 strains pil only or pil and aer. All strains of type O75 possessed afaI and aer. K1 antigen was negative in all strains obtained from UTI.

Animals↗
PubMed1999

[Long-term efficacy of the Gittes bladder neck suspension with use of ultrasonography for genuine stress urinary incontinence].

Thirty-eight patients with genuine stress incontinence underwent the Gittes procedures of the bladder neck suspension under ultrasonical monitoring. We performed the following two procedures. Original Gittes procedure: the puncture of the needle made twice through the different holes of the rectus fascia for each side and the bilateral helical suture was tied down separately above the rectus fascia. Modified Gittes procedure: the needle was passed through the rectus fascia once for each side and the both end of the helical suture was drawn up to suprapubic area, then the bilateral threads were tied over the rectus fascia. Original Gittes procedure was performed for twenty-nine patients and modified Gittes procedure for nine patients. Tightness of the suspension was decided by monitoring the posterior urethrovesical angle with use of the transrectal ultrasonography during the operation. A long term follow up survey was made up by means of a questionnaire by the phone or the mail. A total of thirty-six patients responded the questionnaire for a 94.7% response rate. The mean follow up was 33.1 months. 83.3% of the patients were cured and 5.6% were significantly improved. None of the patients claimed dysuria. There was no difference between the continent rates of the two procedures. We conclude that the Gittes bladder neck suspension with use of ultrasonography is effective for correction of female stress urinary incontinence.

Aged↗
PubMed1999

[Metastatic testicular tumor requiring inferior vena cava resection with polytetrafluoroethylene graft replacement: a case report].

A 31 year-old man with a biopsy-proved retroperiotoneal yolk sac tumor was referred to our clinic. Physical examination revealed a thum- tip sized left supra-clavicular mass, a huge right abdominal mass and a tiny hard mass of the right testis. On CT scan, the abdominal tumor, 13 cm in diameter, encircled the inferior vena cava. Serum levels of LDH, AFP and hCG-beta were 2,585 U/l, 19,922 ng/ml and 6.6 ng/ml, respectively. No visceral metastasis was found. Following the right high orchiectomy, 4 cycles of VIP chemotherapy consisting of ifosfamide, etoposide and cisplatin were given, which resulted in partial response of the retroperitoneal mass and complete regression of the supraculavicular node with normalization of all tumor markers. Thus, retroperitoneal lymph node dissection was carried out. Because of the marked adhesion to the tumor, the inferior vena cava was segmentally resected together with the tumor, which was followed by reconstruction of the vena cava using a 16 cm long polytetrafluoroethylene graft, since no collateral venous route was found on the pretreatment venacavography. Histologically, the tumor was nearly necrotic with mature teratoma in small part. Postoperative clinical course was uneventful except feeling of numbness at the right tip toe, and the inferior vena cava has been patent 18 months after the operation with no evidence of recurrence.

Adult↗
PubMed1999

[Validity analysis of Sapporo Medical University-sexual function questionnaire].

BACKGROUND: We evaluated the validity of the Sapporo Medical University-sexual function questionnaire, comparing the response to each question of patients having sexual dysfunction with those of normal volunteers as controls. PATIENTS AND METHODS: Responses from 335 patients with sexual dysfunction and 490 normal volunteers aged from 20 to 39 years old were evaluated. We compared mean scores of each question for patients having sexual dysfunction with those for controls. Discriminant analysis was used for evaluating which questions contributed more strongly to discriminating patients having the disease from controls. The analysis was also used for validating the questionnaire. RESULTS: Mean scores for patients with sexual dysfunction were significantly lower than those for controls in all questions. Nine of the 11 questions were statistically useful to discriminate these two groups with discriminant analysis. The analysis also revealed that questions about frequency of erection, rigidity of the erectile penis and duration of erection highly contributed to discriminate these two groups. The discriminant analysis achieved high sensitivity and specificity for classifying the groups. CONCLUSION: These results suggest that the use of the Sapporo Medical University-sexual function questionnaire is valid for discriminating patients with sexual dysfunction from subjects with normal sexual function.

Adult↗
PubMed1999

Anatomical studies of the autonomic nervous system in the human pelvis by the whole-mount staining method: left-right communicating nerves between bilateral pelvic plexuses.

PURPOSE: Some recent neurophysiological studies have suggested cross-innervation of pelvic genitourinary organs by extrinsic left-right communicating nerves. However, no definite course for these nerves has been clearly determined macroanatomically in humans. In the present study we extensively investigated the adult human pelvis to elucidate their courses by the whole-mount staining method. MATERIALS AND METHODS: A total of 6 male human specimens that had been subjected to pathological dissection were examined by means of an acetylcholinesterase whole-mount staining method. A map of nerve pathways was made by composite photomicrography. Histologically, nerves dissected accurately under a dissecting microscope were stained with both Klüver-Barrera stain and the Bodian method. RESULTS: The communicating nerves between bilateral pelvic plexuses were observed at the back of the rectum and in the rectoprostatic space. The former were composed of nothing but myelinated fibers in the same way as the pelvic splanchnic nerve. By contrast, the latter were composed of unmyelinated fibers with a few myelinated fibers. The pelvic plexus could be divided into three portions, anterosuperior, anteroposterior and inferior areas, by ganglion type. Morphologically, fiber components differed among those three portions. CONCLUSION: The communicating nerves at the back of the rectum seemed to be predominantly parasympathetic communicantes between bilateral pelvic splanchnic nerves rather than pelvic plexuses. These nerves may be involved in postoperative voiding function in the case of pelvic surgery with hemilateral nerve preservation. The function of the pelvic plexus seemed to be heterogeneous in each portion according to our morphological results.

Aged↗
PubMed1999

Post-traumatic arterial priapism evaluation with color Doppler ultrasonography: a case report.

The patient was a 19-year-old man who was examined due to persistent penile erection, which appeared following a blow to the perineal region during work. Color Doppler ultrasonography of the corpora cavernosa revealed a cavity in one part of the cavernous artery that suggested a blood leak, and a diagnosis of high flow type priapism due to trauma was made. Bilateral internal pudendal arteriography demonstrated dilation and extravasation in one part of the right cavernous artery, then transarterial embolization was performed superselectively in the right cavernous artery using an autologous clot. However, 2 weeks after treatment, slight penile erection reoccurred. Color Doppler ultrasonography revealed reformation of the cavity at the treated lesion, and embolization was again performed using a gelatin sponge. Following embolization, the course proceeded satisfactorily without any relapse. Color Doppler ultrasonography, which is non-invasive and can be easily performed, is considered to be an effective means for diagnosis and follow up of arterial high flow priapism.

Adult↗