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T Umehara

Publications and source records attributed to T Umehara.

At least 19 recordsLinked to original sources
PubMed2001

Cell death with predominant apoptotic features in Saccharomyces cerevisiae mediated by deletion of the histone chaperone ASF1/CIA1.

BACKGROUND: Although no potential homologues of multicellular apoptotic genes (e.g. Bax, Bak, Bcl-2, caspases and p53) have been identified in a unicellular eukaryote, previous reports contain several implications of the apoptotic behaviour of yeasts (i.e. Saccharomyces cerevisiae and Schizosaccharomyces pombe). Therefore, whether or not yeast undergoes apoptosis has been a topic of some debate. hCCG1, which is the largest subunit of TFIID and a histone acetyltransferase, appears to be involved in the regulation of apoptosis. The factor hCIA interacts with hCCG1 and functions as a histone chaperone in mammalian cells; its homologue in yeast is Asf1p/Cia1p. Therefore, we anticipated that a yeast mutant in Asf1p/Cia1p would be a valuable tool for studying apoptosis in yeast. RESULTS: We established a strain of S. cerevisiae lacking the histone chaperone ASF1/CIA1. This disruptant, asf1/cia1, arrested preferentially at the G2/M-phase and died. We systematically analysed the phenotype associated with the death of this mutant yeast and identified many changes, such as fragmentation of the nuclei, condensation and fragmentation of chromatin, reduction of the mitochondrial membrane-potential, dysfunction of the mitochondrial proton pump, and a discernible release of cytochrome c to cytoplasm that resembles those in apoptotic multicellular organisms. Other changes potentially associated with the death in our mutant included a reduction in the vacuolar membrane potential, dysfunction of the vacuolar proton pump, reduction of endocytosis, and the presence of many autophagic bodies. However, these mutant yeast cells also showed cellular enlargement, which is characteristic of necrosis. CONCLUSIONS: Cell death in S. cerevisiae occurs with a phenotype that largely resembles apoptosis in multicellular organisms, but that has some features of necrosis. Therefore, we indicate that yeast undergoes a 'prototypal active cell death' that retains some characteristics of passive cell death (necrosis). In addition, we think that active cell death is ubiquitously the essential attribute of life. Although such an active cell death system in yeast remains open to confirmation, we speculate that deletion of the histone chaperone Asf1p/Cia1p inhibits the normal assembly/disassembly of nucleosomes in yeast and thereby initiates the active cell death system.

Animals↗
PubMed2001

Recognition of tRNA by aminoacyl-tRNA synthetase from hyperthermophilic archaea, Aeropyrum pernix K1.

To study the recognition sites of tRNA for archaeal aminoacyl-tRNA synthetase, several aminoacyl-tRNA synthetase genes from hyperthermophilic archaeon, Aeropyrum pernix K1 were cloned and expressed. All the expressed enzymes showed extreme thermostability. Expressed threonyl-tRNA synthetase threonylated not only archaeal (A. pernix and Haloferax volcanii) threonine tRNAs but also Escherichia coli threonine tRNA. However, threonyl-tRNA synthetase from H. volcanii did not threonylate E. coli threonine tRNA.

Desulfurococcaceae↗
PubMed2000

Threonyl-tRNA synthetase of archaea: importance of the discriminator base in the aminoacylation of threonine tRNA.

To investigate the contribution of the discriminator base of archaeal tRNA(Thr) in aminoacylation by threonyl-tRNA synthetase (ThrRS), cross-species aminoacylation between Escherichia coli and Haloferax volcanii, halophilic archaea, was studied. It was found that E. coli ThrRS threonylated the H. volcanii tRNA(Thr) but that E. coli threonine tRNA was not aminoacylated by H. volcanii ThrRS. Results of a threonylation experiment using in vitro mutants of E. coli threonine tRNA showed that only the mutant tRNA(Thr) having U73 was threonylated by H. volcanii ThrRS. These findings indicate that the discriminator base U73 of H. volcanii tRNA(Thr) is a strong determinant for the recognition by ThrRS.

Escherichia coli↗
PubMed1997

Restricted expression of a member of the transcription elongation factor S-II family in testicular germ cells during and after meiosis.

Whether expression of transcription elongation factors is regulated during development has not been investigated, though genes encoding elongation factor S-II are transcribed in a tissue-specific manner. We investigated the expression profile of tissue-specific S-II during development using an isolated cDNA, termed mouse S-II-T1, whose transcripts are detected almost exclusively in testis. Three experiments were performed with various types of germ and somatic cells in testis to determine in which cells S-II-T1 is expressed. (1) Expression of S-II-T1 is markedly reduced in the testes of adult WBB6F1-W/Wv mutant mice which lack testicular germ cells, indicating its expression is specific to testicular germ cells. (2) The onset of mouse S-II-T1 mRNA appearance in testis is seen about 10-14 days after birth, which is consistent with the start of meiotic events, suggesting that S-II-T1 is not transcribed in premeiotic and early meiotic cells such as spermatogonia, leptotene spermatocytes, or zygotene spermatocytes. (3) Mouse S-II-T1 transcripts accumulate in meiotic pachytene spermatocytes and are detected in postmeiotic haploid cells such as round and elongated spermatids during spermatogenesis, as shown by fractionation of testicular germ cells at four different stages. These results indicate that expression of mouse S-II-T1 is restricted to testicular germ cells during and after meiosis in the course of spermatogenesis. This is the first report that expression of a transcription elongation factor in particular cells is regulated in a stage-specific manner in the course of development.

Amino Acid Sequence↗
PubMed1997

[Endoscopic reconstruction after traumatic disruption of the urethra].

Endoscopic reconstruction was performed in 5 patients after complete traumatic disruption of the urethra. A prostatic urethra was disrupted in 1 patient, prostatic and membranous urethrae in 1 and bulbous urethra in 3. After endoscopic reconstruction, all patients required additional internal urethrotomy and urethral bougienage, but became able to void by themselves. Four patients had maximum flow rates between 13.8 and 41.9 ml/s. However, the other patient with an obliterated urethral segment of 4.6 cm had traumatic impotence preoperatively and a poor voiding status after reconstruction. None of the patients developed urinary incontinence or impotence associated with the operation. In conclusion, endoscopic reconstruction is recommended as the initial procedure for patients with obliterated segments smaller than 3 cm.

Accidents, Occupational↗
PubMed1997

Relationship between DNA ploidy and functional estrogen receptors in operable prostate cancer.

OBJECTIVE: To evaluate the relationship between the nuclear DNA content and the tissue estrogen receptor (ER) level in patients with operable adenocarcinoma of the prostate. METHOD: Surgical specimens taken from 73 patients with clinically localized prostate cancer were studied. Tumor DNA ploidy pattern as measured by flow cytometry was correlated with the level of functional ER using the nuclear biopsy assay. RESULTS: Forty-five percent of the tumors were DNA diploid, and 55% had an abnormal ploidy pattern (DNA tetraploid or DNA aneuploid). The ER level ranged from 0 to 6,475 fmol/mg DNA (mean 839 fmol/mg DNA). Twenty-two percent had no functional receptors. Marked association was noted between ER and nuclear DNA content. Seventy-five percent of the tumors with no ER had abnormal ploidy patterns. The mean receptor level for DNA diploid prostate cancer was 1,034 fmol/mg DNA versus 661 fmol/mg DNA for DNA nondiploid tumors (p < 0.008). An inverse correlation was found between ER values and histologic grade or pathologic stage. High-grade and high-stage tumors had lower levels of ER compared to low-grade and early-stage carcinomas. CONCLUSION: Our results demonstrate an association between ER values and variables that predict prognosis in prostate cancer. It is possible that this parameter may be helpful in identification of prognostic groups in patients with prostate cancer.

Adenocarcinoma↗
PubMed1996

A synthetic oestrogen antagonist, tamoxifen, inhibits oestrogen-induced transcriptional, but not post-transcriptional, regulation of gene expression.

Oestrogen (E2) regulates the expression of its target genes at transcriptional and post-transcriptional levels. To clarify the mechanism of E2-induced post-transcriptional regulation, with attention to the involvement of the oestrogen receptor (ER), we studied the effect of tamoxifen (TAM), a synthetic E2 antagonist that inhibits ER-mediated transcription, on E2-induced transcriptional and post-transcriptional regulation of the chicken ovalbumin (OVA) gene in chick oviducts. Run-on analysis with oviduct nuclei isolated from E2-treated chicks showed that TAM treatment completely blocked E2-induced transcription of the OVA gene within 24 h without affecting ER gene expression. Likewise, the rate of transcription fell to below the limit of detection after E2 withdrawal from the chicks. Reflecting the transcription rate, OVA mRNA accumulated linearly in E2-treated chicks, and E2 withdrawal caused a rapid loss of OVA mRNA. However, in the chicks treated with TAM and E2, OVA mRNA was degraded slowly over 48 h with a half-life of 24 h, suggesting that TAM does not inhibit E2-induced mRNA stabilization. Moreover, E2-induced mRNA stabilization was observed even when transcription of the OVA gene was blocked by a transcription inhibitor. Western-blot analysis showed that the remaining OVA mRNA was translatable. Thus the present study indicates that E2 regulates expression of the OVA gene via distinct pathways at transcriptional and post-transcriptional levels.

Animals↗
PubMed1996

Reversible suppression of pituitary-testicular function by a sustained-release formulation of a GnRH agonist (leuprolide acetate) in dogs.

Pituitary-testicular function was studied in 15 dogs following treatment with a sustained-release formulation of a GnRH agonist, leuprolide acetate (LA). Adult male dogs were treated with a single subcutaneous injection of microencapsulated LA (0.1 or 1 mg/kg). Treatment with LA at a dose of 1 mg/kg resulted in decreased (P<0.001) ejaculatory volume and disappearance of morphologically normal spermatozoa within 8 wk and the effect persisted for 6 wk, while the 0.1 mg/kg dose was not adequate to effect suppression of spermatogenesis. The larger dose treatment (1 mg/kg) caused a transient rise in plasma levels of LH and testosterone followed by a marked decline to below the normal level by 2 wk, the low levels being maintained for at least 5 wk, indicating a prolonged effect of LA treatment on pituitary-gonadal axis. Twenty weeks after treatment with LA, a complete return to normal spermatogenesis was observed. The full reversibility of spermatogenesis in the dog after LA treatment suggests that this peptide could be used as a reversible method of male contraception.

Journal Article↗
PubMed1996

[A clinical study of radial prostatectomy].

BACKGROUND: The objective of this study is to evaluate the efficacy of radical prostatectomy for patients with organ-confined prostate cancer. METHODS: From 1990 to 1994, a total of 50 patients with prostate cancer underwent radical retropubic prostatectomy. RESULTS: Eleven patients were in state A2, 34 in stage B and 5 in stage C according to clinical stage. Extended disease was observed pathologically in 45%, and 59% of patients in clinical stages A2 and B, respectively. Preoperative serum PSA levels were closely correlated with pathological extension of the disease. The disease-free rates for organ-confined disease, extended disease without lymph node metastasis and stage D1 disease were 75% (3 years), 82% (2 years) and 80% (3 years), respectively. Four patients had rectal injuries, and three of these underwent temporary colostomy diversion. Two patients had bladder neck contracture and received internal urethrotomy. Urinary incontinence improved in 60% of patients during the first 6 post-operative and in 90% of patients within 12 post-operative months. Urinary incontinence tended to improve earlier in patients with nerve-sparing than those without it. The erectile capacity in nerve sparing patients recovered good. CONCLUSION: Our results indicate that radical prostatectomy is a safe and temporarily satisfactory treatment for the patient with organ-confined prostate cancer.

Adenocarcinoma↗
PubMed1996

Human body textbook with three-dimensional illustrations.

We made a toolkit for making education softwares using 3D computer graphics, and using the toolkit, we made an education software based on 3D illustrations for learning about the human body. The toolkit enables us to make such kind of education software based on 3D illustrations easy and systematic. In the education software, the human body structure is illustrated with 3D models. The user can see the 3D objects with real-time rotation and walk through the virtual space, and their functions are expressed in the 3D virtual space.

Anatomy, Cross-Sectional↗
PubMed1995

Isolation and characterization of a cDNA encoding a new type of human transcription elongation factor S-II.

We report the isolation of a cDNA encoding a new type of transcription factor S-II, termed h-SII-T1, from a human library. The mRNA corresponding to the clone is highly expressed in testis and ovary. Comparison of the deduced amino acid (aa) sequence with those of other S-II molecules shows that (i) the C-terminal zinc finger (Zf) domain is highly conserved, and (ii) the central segment is most similar to that of the rat testis-specific S-II. Further analyses of the hS-II-T1 aa sequence indicate that its N-terminal sequence exhibits similarity to eubacterial sigma 54. The significance of tissue-specific S-II molecules for the regulation of transcription elongation is discussed.

Amino Acid Sequence↗
PubMed1995

Isolation of a cDNA encoding a mouse TFIID subunit containing histone H4 homology.

A cDNA encoding a mouse transcription factor IID (TFIID) subunit, containing histone H4 homology, was cloned and sequenced. The predicted 678-amino-acid (aa) sequence of this molecule showed 97 and 41% identity to the human and Drosophila melanogaster homologues, respectively. Four putative direct repeats were found in the most highly conserved region in the central part of this protein.

Amino Acid Sequence↗
PubMed1995

Three distinct regions in a rat TFIID subunit containing histone H4 homology.

A cDNA encoding a rat transcription factor IID (TFIID) subunit (p80), with histone H4 homology, was isolated and sequenced. The deduced amino acid (aa) sequence predicts a 678-aa protein with 97% identity to the human and 42% to the Drosophila melanogaster (Dm) homologues. Homologies between three species indicate the presence of three distinct regions.

Amino Acid Sequence↗
PubMed1995

[Clinical efficacy of lomefloxacin (100 mg or 300 mg) single-dose therapy in female acute uncomplicated cystitis].

Female acute uncomplicated cystitis responds relatively well to antimicrobial chemotherapy. In particular, new quinolones are suited for use as antimicrobial agents in single-dose therapy of female acute uncomplicated cystitis since they have a long serum half-life and express potent antimicrobial activity against the causative microbes of this infection. Lomefloxacin (LFLX) is one such new quinolone which shows a long serum half-life, expresses potent antimicrobial activity against Escherichia coli (E. coli) and maintains an effective urinary drug concentration for approximately three days after a single administration. The authors carried out a comparative investigation of the clinical efficacy of single doses of 100 mg and 300 mg of LFLX in the treatment of female acute uncomplicated cystitis. The clinical efficacy rates with these doses, evaluated on the 3rd day after administration, were 98.2% (56/57 cases) for the 100mg-LFLX dose and 100% (62/62 cases) for the 300-mg LFLX dose. When the evaluation was performed on the 7th day after administration, the clinical efficacy rates were 91.3% (42/46 cases) for the 100-mg LFLX dose and 95.8% (46/48 cases) for the 300-mg LFLX dose. In addition, the microbial eradication rates were 73.7% (42/57 cases) for the 100-mg LFLX group and 75.8% (47/62 cases) for the 300-mg LFLX group on the 3rd day after administration, and 71.7% (33/46 cases) for the 100-mg LFLX group and 83.3% (40/48 cases) for the 300-mg LFLX group on the 7th day after administration. Although there were no statistically significant differences between the two LFLX dosage groups for these parameters at either of the evaluation times, the rates for the 300-mg LFLX dose were slightly superior. The investigators judged the efficacy of the LFLX treatment as having been insufficient in 12 patients, and urological examinations performed on six of those cases determined that there were mild underlying diseases in four cases, such as stenosis of the urethral meatus. On the basis of the findings described above, it is clear that a single 100-mg dose of LFLX provided sufficient clinical efficacy in the treatment of female acute uncomplicated cystitis, but the efficacy of the 300-mg dose of LFLX was even better. In addition, it was surmised that performance of detailed urological examinations provides an opportunity to detect mild underlying diseases that may be the cause of the intractability in female acute uncomplicated cystitis cases showing an insufficient response to treatment with antimicrobial agents such as LFLX.

Acute Disease↗
PubMed1995

[Long-term monitoring of female acute uncomplicated cystitis cases after lomefloxacin single-dose therapy].

Female acute uncomplicated cystitis responds relatively well to antimicrobial chemotherapy, but this is also a disease which shows a high frequency of recurrence. However, there have been no published reports regarding long-term monitoring of the course of this disease after therapy has been administered. Accordingly, using primarily a questionnaire, the authors carried out long-term monitoring (for a mean of 242 days) of the natural course of cases of female acute uncomplicated cystitis after single-dose therapy with lomefloxacin (LFLX), a new quinolone antimicrobial agent. The subjects of this study were female patients diagnosed as having acute uncomplicated cystitis with pain upon urination, pyuria (> or = 10 WBCs/hpf) and bacteriuria (> or = 10(4) cfu/ml). LFLX was orally administered as a single dose of 100 mg or 300 mg, and the therapeutic efficacy was evaluated on the 3rd and 7th days thereafter. In principle, the evaluation of cure was performed on the 7th day after LFLX administration, and monitoring was conducted to detect early recurrence during the next 7 days (i.e., through the 14th day after treatment). Then the subjects were monitored for late recurrence during a mean follow-up period of 242 days by means of a questionnaire. Confirmation of recurrence was carried out to the greatest extent possible. It was possible to carry out long-term monitoring of the natural course of 101 cases of female acute uncomplicated cystitis in which the clinical efficacy on the 3rd day after LFLX treatment had been evaluated as good or excellent.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1995

Mass screening for prostate carcinoma: a study in Hokkaido, Japan.

Although there has been controversy about the early detection of prostate carcinoma by mass screening, we carried out an investigational study of such screening, using digital rectal examination (DRE) and serum prostate-specific antigen (PSA) determination in Hokkaido, Japan. We determined the detection rate and some profiles of the carcinoma detected by screening in Japanese men 50 years old and older. The detection rate of carcinoma was 1.10% in 1,639 participants. The rate linearly increased with aging from 0.25% for men in their fifties to 2.29% for those in their seventies. Two thirds of the carcinomas were T1(c) or T2, the frequency of which seemed to be higher than that of patients who visited medical institutions. The simultaneous use of both DRE and serum PSA determination showed a higher positive predictive value than either alone. Our current results indicated that the detection rate of carcinoma was higher than we previously anticipated for Japanese men, and that simultaneous use of DRE and serum PSA determination yielded a higher positive predictive value than either alone.

Aged↗