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Biomedical subjects

T Tani

Publications and source records attributed to T Tani.

At least 73 records · Page 4Linked to original sources
PubMed2000

Hypoxic conditions restore lost sensitivity to the growth inhibitory effect of transforming growth factor beta-1 (TGF beta-1) in proliferating rat hepatocytes in vitro.

TGF beta-1 is known to be a growth inhibitor of regenerating liver, and an inducer of hepatocyte apoptosis in primary culture. However, hepatocytes can proliferate after partial hepatectomy even at high serum TGF beta-1 concentrations. In this study we used the primary cultures of rat hepatocytes for 10 days to investigate how TGF beta-1 affects proliferating hepatocytes. DNA synthesis peaked on day 8 of culture, and TGF beta-1-induced apoptosis was significantly suppressed on day 8 compared to days 2, 5, and 10. Flow-cytometric analysis revealed that hepatocytes that had incorporated BrdU were resistant to the apoptotic effect of TGF beta-1, and Northern blot analysis showed that TGF beta receptor mRNA was down-regulated on day 8. Hypoxic conditions restores TGF beta receptor mRNA expression and the lost sensitivity of proliferating hepatocyte to TGF beta-1.

Animals↗
PubMed2000

Efficient cryopreservation of bovine blastocysts derived from nuclear transfer with somatic cells using partial dehydration and vitrification.

Preservation by vitrification of Day 7 and Day 8 bovine blastocysts derived from nuclear transfer with cumulus cells was compared with preservation of in vitro fertilized blastocysts. In Experiment 1, embryos were vitrified in PBS containing 60% ethylene glycol. In Experiment 2, they were vitrified in combination with partial dehydration using a solution of 39% ethylene glycol + 0.7 M sucrose and 8.6% Ficoll. In Experiment 1, survival and hatching rates were 44 and 95% for nuclear transferred embryos, and 78 and 55% for in vitro fertilized embryos, respectively. In Experiment 2, survival and hatching rates were 93 and 95% for nuclear transfer embryos, and 77 and 85% for in vitro fertilized embryos, respectively. It is concluded that Day 7 and Day 8 bovine blastocysts derived from cumulus cells could be cryopreserved without the loss of viability by a simple and efficient method using a combination of partial dehydration and vitrification.

Animals↗
PubMed2000

Production of mice derived entirely from embryonic stem cells after injecting the cells into heat treated blastocysts.

The sensitivity of the inner cell mass (ICM) and trophectoderm (TE) of mouse blastocysts to high temperatures was examined. When blastocysts with a diameter of 100 to 120 microm treated for 15 to 20 min at 45 degrees C were cultured in vitro, the cell number in the ICM did not increase, although that in the TE did increase. After transfer of treated blastocysts to recipients, implantation was not drastically inhibited but no live fetuses were obtained. These results demonstrated that the ICM at the blastocyst stage was more sensitive to high temperature than the TE. ICM clumps or ES cells were injected into blastocysts treated for 20 min at 45 degrees C. After transfer of injected blastocysts to recipients, we obtained mice derived completely from ICM or ES cells as judged by GPI analysis. Since 4 of 7 ES-cell derived mice, but none of the 6 mice derived from the ICM died after birth, an as yet unidentified epigenetic alteration might have occurred during the establishment and/or culture of ES cells.

Animals↗
PubMed2000

Alteration of beta-catenin expression in esophageal squamous-cell carcinoma.

beta-catenin regulates cadherin-mediated cell-cell adhesion and also functions as a signaling molecule. In this study, we examined the expression pattern of E-cadherin, alpha-catenin and beta-catenin in 22 cases of esophageal squamous-cell carcinoma by Western-blot analysis. Expression of E-cadherin, alpha-catenin and beta-catenin was lower in carcinomas than in normal esophageal mucosa in 4 cases (18.2%) for E-cadherin, 6 cases (27.3%) for alpha-catenin and 9 cases (40.9%) for beta-catenin. Expression of beta-catenin was not always correlated with that of E-cadherin. Over-expression of beta-catenin was observed in 3 cases (13.6%). Of 3 cases that presented with over-expression of beta-catenin, 2 showed cytoplasmic staining by immunohistochemistry. Nuclear localization of beta-catenin was observed in one case that had higher beta-catenin level in tumor tissue (1.4-fold higher than normal mucosa). The genomic DNA sequences of the beta-catenin and the APC gene were analyzed. No mutation of the beta-catenin gene was observed in any cases. Silent mutation of the APC gene was found in all the cases that showed over-expression or nuclear localization of the beta-catenin protein. These results indicate that alterations of the cadherin-catenin complex may play an important role in a sub-set of esophageal carcinogenesis. Furthermore, it is suggested that beta-catenin over-expression is not caused by genetic alteration of either the beta-catenin or the APC gene.

Blotting, Western↗
PubMed2000

Activation of immediate early gene, c-fos, and c-jun in the rat small intestine after ischemia/reperfusion.

BACKGROUND: Activated immediate early genes (IEGs) play key roles in mediating cellular response after ischemia/reperfusion (I/R) injuries in some organs such as liver, heart and kidney. However, there is no report investigating an association between the activation of IEGs and cellular regeneration or programmed cell death after I/R in small intestine. METHODS: We examined a sequential expression of c-fos and c-jun after I/R in rat small intestine using reverse transcription-polymerase chain reaction and Northern blot analysis, and compared the patterns with coexistent two parameters: (1) regeneration determined by immunohistochemical detection of proliferating cell nuclear antigen, (2) programmed cell death determined with the terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end-labeling (TUNEL) method and DNA fragmentation. RESULTS: The expression of c-fos and c-jun mRNA increased markedly 15 min after reperfusion and was, respectively, 6.3 and 4.4 times higher than in controls. Proliferating cell nuclear antigen expression was significantly elevated between 5 min and 4 hr, peaking at 30 min after reperfusion. Apoptosis showed a peak 60 min after reperfusion. Apoptosis after I/R was detected in the nuclei of absorptive epithelial cells by the TUNEL method, and these apoptotic signals were consistent with the expression of c-Fos and c-Jun proteins using an immunohistochemical method. CONCLUSIONS: These results suggest that overexpression of c-fos and c-jun after I/R in the small intestine correlates with programmed cell death and subsequent cellular regeneration.

Animals↗
PubMed2000

Mutations in the large subunit of U2AF disrupt pre-mRNA splicing, cell cycle progression and nuclear structure.

The prp2 gene of fission yeast has previously been shown to encode the large subunit of the splicing factor spU2AF. SpU2AF(59) is an evolutionarily conserved protein that has an arginine/serine-rich region and three RNA recognition motifs (RRMs). We have sequenced three temperature-sensitive alleles of prp2 and determined that the mutations result in single amino acid changes within one of the RRMs or between RRMs. All mutant alleles of prp2 have pre-mRNA splicing defects at the non-permissive temperature. Although the mutant strains are growth-arrested at 37 degrees C, they do not elongate like typical fission yeast cell cycle mutants. The DNA of the prp2(-) strains stains more intensely than a wild-type strain, suggesting that the chromatin may be condensed. Ultrastructural studies show differences in the mutant nuclei including a prominent distinction between the chromatin- and non-chromatin-enriched regions compared to the more homogenous wild-type nucleus. Two-hybrid assays indicate that some of the wild-type protein interactions are altered in the mutant strains. These results suggest that normal functioning of spU2AF(59) may be essential not only for pre-mRNA splicing but also for the maintenance of proper nuclear structure and normal cell cycle progression.

Alleles↗
PubMed2000

Protease inhibitor reduces loss of tensile strength in rat anastomosis with peritonitis.

BACKGROUND: The tensile strength in intestinal anastomoses decreases postoperatively in association with degradation of the extracellular matrix, and these changes would be expected to be more intense in the presence of peritonitis. MATERIALS AND METHODS: In this study, we investigated extracellular matrix degradation and tensile strength in a rat model of intestinal anastomosis with peritonitis. In the chemical peritonitis model, peritonitis was induced 24 h earlier with intraperitoneal HCl. A serine protease inhibitor, nafamostat mesilate (NM), was given intraperitoneally to some animals every 12 h from immediately after the operation for 3 days. Immunostaining was performed by the standard streptavidin-biotin-peroxidase method after fibronectin (Fn) and factor XIII antigen retrieval on paraformaldehyde-fixed, paraffin-embedded tissue sections. RESULTS: In comparison with controls, administration of NM reduced the loss of tensile strength on Day 3 in a dose-dependent manner, and high-dose NM (20/mg/kg) significantly prevented the loss of tensile strength on Day 3 (P < 0. 05). In the control group, degradation of the collagen layer in the anastomosis was associated with disappearance of Fn and factor XIII staining on Day 3. The administration of NM attenuated these changes with intense immunostaining for Fn and factor XIII seen particularly between collagen fibers on both sides of the anastomosis on Day 3. In the chemical peritonitis model, administration of NM also significantly prevented the loss of tensile strength on Day 3 without disappearance of collagen fibers. CONCLUSION: These findings suggest that NM may be clinically useful for preventing intestinal leakage, particularly when anastomoses are performed under protease-activating conditions, such as intestinal edema and inflammation.

Anastomosis, Surgical↗
PubMed2000

Osteoblastoma-like osteosarcoma.

We report an osteoblastoma-like osteosarcoma in the right proximal fibula in a 22-year-old woman. Radiographs showed an irregular osteolytic lesion from the metaphysis to the epiphysis in the proximal fibula with partial destruction of cortical bone. Tissue from a biopsy indicated a typical osteoblastoma. Curettage and bone graft was performed. One year after the surgery, local recurrence occurred, and a wide excision was performed. Histological examination of the en-bloc surgical specimen revealed the tumor had permeated through the host bony trabeculae, although the nuclear atypia was not marked. Immunohistochemical expression of MIB-1 was detected in 9.0% of cells.

Adult↗
PubMed2000

The effect of trunk muscle exercises in patients over 40 years of age with chronic low back pain.

Previous studies of trunk muscle strength in patients with chronic low back pain (CLBP) have mainly reported on patients aged younger than 40 years. However, no such investigation has yet been done in middle-aged patients. Trunk muscle strength and the effect of trunk muscle exercises were investigated in patients with CLBP aged more than 40 years. Trunk muscle strengths were measured in a LBP group (52 patients) and a control group (60 volunteers) and the results for the two groups were compared. The LBP group was divided into three subgroups. Group A had only age-related spondylosis and group B had disk herniation and spondylolisthesis with age-related spondylotic change. Both these groups were able to continue exercises. Group C was made up of patients who had abandoned the exercise program. Trunk muscle strength and symptoms were assessed in each group. Both flexion and extension strength were decreased in the LBP group compared with the control group, with the reduction in extension strength being most marked. In both groups A and B, muscle strength increased and clinical symptoms improved. In contrast, no change was seen in group C. In older patients with CLBP, reduction of muscle strength was more marked in the spinal extensors than in the spinal flexors. It was confirmed that trunk muscle strengthening exercises are useful for increasing muscle strength and improving symptoms in such patients.

Adult↗
PubMed2000

Cellular distribution and clinical value of urokinase-type plasminogen activator, its receptor, and plasminogen activator inhibitor-2 in esophageal squamous cell carcinoma.

To assess the participation of the plasminogen activation system in the invasiveness of esophageal squamous cell carcinoma, we performed immunohistochemistry and in situ hybridization to study the distribution of a urokinase-type plasminogen activator (u-PA), u-PA receptor (u-PAR), and plasminogen activator inhibitor-2 (PAI-2). u-PA and PAI-2 were expressed heterogeneously in cancer cells, and restricted expression was found in stromal cells, especially fibroblasts, that were located in the immediate proximity of the cancerous cells. u-PAR was found only in cancer cells located at the periphery of tumors. Compared with patients with u-PA-negative cancer cells, patients with u-PA-positive cancer cells more frequently showed a neoplastic invasion beyond the muscularis propria and lymph node metastases. They also showed a significantly shorter 5-year overall survival. Patients with PAI-2-positive fibroblasts showed significantly lower levels of local invasiveness, represented by a neoplastic invasion beyond the muscularis propria, than those who were PAI-2 negative. Our results suggest that the expression of u-PA in esophageal squamous cell carcinoma is predictive of poor survival, whereas the expression of PAI-2 in the fibroblasts surrounding them is protective. An analysis of u-PA and PAI-2 expression in cancer cells and their surrounding fibroblasts may be useful for predicting the prognosis of patients with esophageal squamous cell carcinoma.

Adult↗
PubMed2000

Cilostazol, a selective type III phosphodiesterase inhibitor, decreases triglyceride and increases HDL cholesterol levels by increasing lipoprotein lipase activity in rats.

Cilostazol, a selective type III phosphodiesterase inhibitor, has antiplatelet and vasodilating effects. In this study, the effects of cilostazol on lipid metabolism and lipoprotein lipase (LPL) activity were studied in rats. Cilostazol was administered orally at doses of 30 or 100 mg/kg twice a day for 1-2 weeks to rats. Cilostazol decreased the serum triglyceride level in normolipidemic rats. The serum triglyceride level was reduced and HDL cholesterol level was increased by cilostazol in streptozotocin (STZ)-induced diabetic rats. The disappearance of exogenous triglyceride was accelerated by cilostazol in normolipidemic rats. Cilostazol increased post-heparin plasma LPL activity but had no effect on hepatic triglyceride lipase activity in STZ-induced diabetic rats. Cilostazol also increased LPL activity in the heart in STZ-induced diabetic rats. These findings suggest that an increase in LPL activity is responsible for the serum triglyceride lowering and HDL cholesterol elevating effects of cilostazol in rats.

Animals↗
PubMed2000

Developmental potential of cumulus cell-derived culture frozen in a quiescent state after nucleus transfer.

An efficient method for freezing donor cells is necessary when using nucleus transfer of somatic cells for large-scale cloning. In the present study, we developed a method for freezing and thawing bovine cumulus cell-derived cultured cells to be used as nucleus donors. Cumulus cells were obtained from ovaries of living and slaughtered bovine and cultured in vitro. Cumulus cell-derived cultured cells were serum-starved for several days to induce a quiescent state and then frozen at -70 degrees C for at least 2 d. Immediately thereafter or 2 h after thawing, the cells were used as donor cells for nuclear transfer without additional in vitro culture. The fusion rate with recipient cytoplasts was not affected by the cumulus cell source (slaughtered or living) or time after thawing (0 and 2 h). The cleavage rate of frozen-thawed cumulus cell-derived cultured cells from slaughtered cows immediately after thawing (0 h) was highest (97%) and was significantly higher than that of controls (85%) or cells transferred 2 h after thawing (85%). There were no significant differences among any of the groups in the potential of the nuclear transfer embryos to develop into blastocysts (34 vs 44 and 44%, 39 vs 45 and 46%). Thus, storage of bovine cumulus cell-derived cultured cells in the quiescent state at -70 degrees C is effective and might be useful and convenient for large-scale cloning. The maximum storage periods and developmental potential of embryos after such nucleus transfers requires further examination.

Animals↗
PubMed2000

Coumarins from the fruits of Cnidium monnieri.

Two novel biscoumarins, cnidimonal (1) and cnidimarin (2), and two new coumarin derivatives, 5-formylxanthotoxol (3) and 2'-deoxymeranzin hydrate (4), were isolated from a traditional Chinese crude drug, the fruits of Cnidium monnieri, together with 15 known compounds. Among the known compounds, five of the minor compounds were isolated for the first time from this plant. The structures of 1-4 were determined with the use of spectroscopic methods.

Apiaceae↗
PubMed2000

Occult breast cancer presenting axillary nodal metastasis: a case report.

We report a case of a 42-year-old female with occult breast cancer presenting axillary nodal metastasis. She complained of a swelling of the right axillary lymph node, but no breast mass was palpable. Biopsy of the lymph node was performed and histological examination showed a metastatic ductal carcinoma with papillotubular formation. Estrogen receptor of the lymph node was positive. No pathological findings were obtained by mammography and ultrasonography and systemic examinations revealed no extramammary primary lesion. All these data suggested an occult carcinoma of the breast and modified radical mastectomy was performed. Pathological findings of the removed specimen failed to find the primary breast cancer lesion. The patient has been treated with hormonal therapy and she is well without evidence of disease 5 years after surgery.

Adult↗