Biomedical subjects

Takeshi Miura

Publications and source records attributed to Takeshi Miura.

At least 19 recordsLinked to original sources

PubMed2006

Cloning and functional characterization of the copper/zinc superoxide dismutase gene from the heavy-metal-tolerant yeast Cryptococcus liquefaciens strain N6.

The deep-sea yeast Cryptococcus liquefaciens strain N6 possesses high superoxide dismutase (SOD) activity and a high tolerance toward metal ions. To clarify the relationship between metal tolerance and SOD activity in this strain, we cloned the Cu/Zn SOD gene. This gene (Cl-SOD1) consists of 471 bp encoding 157 amino acids; the associated protein had 59.9-76.7% identity with Cu/Zn SOD proteins of other yeast species. The highest identity corresponded to Cryptococcus gattii (76.7%). Cl-SOD1 expression in the sod1 mutant of Saccharomyces cerevisiae revealed that this SOD protein was functional in S. cerevisiae. The Cl-SOD1 protein possessed approximately fourfold greater activity than S. cerevisiae SOD1 (Sc-SOD1) at 30 degrees C. The amount of Cl-SOD1 mRNA in strain N6 increased in the presence of copper ion. However, the level of this transcript was not dependent on an increase in copper ion concentration and did not correlate well with changes in the amount of Cu/Zn SOD protein. This result suggests that strain N6 possesses other Cu/Zn SOD genes induced in a manner different from Cl-SOD1 as found in Candida albicans, or that the Cl-SOD1 gene undergoes posttranscriptional regulation upon increase of copper ion.

Candida albicans↗

PubMed2006

Expression of vasa (vas)-related genes in germ cells and specific interference with gene functions by double-stranded RNA in the monogenean, Neobenedenia girellae.

Neobenedenia girellae, a monogenean, is an important pathogen in marine cultured fish such as yellowtail and amberjack. An effective control method is required but none has yet been established. Aiming to establish a new control method by interfering with the gametogenesis of N. girellae, we focused on vasa (vas)-related genes that are expressed exclusively in the germline granules in Drosophila, Caenorhabditis elegans and other animals. Three vas-related genes (N. girellae vasa-like gene, Ngvlg1, Ngvlg2 and Ngvlg3) were isolated by PCR and Ngvlg1 and Ngvlg2 were shown to be expressed only in germ cells. We demonstrated that introduction of double-stranded Ngvlg1 or Ngvlg2 RNA by soaking resulted in partial or complete loss of germ cells. Moreover, the hatching rate of eggs from animals showing partial loss of germ cells decreased significantly. These results suggest that Ngvlg1 and Ngvlg2 are essential genes for germ cell quantity and quality. The possibility that a new control method can be developed by controlling gametogenesis of N. girellae was proven, because sterilised N. girellae could be produced.

Amino Acid Sequence↗

PubMed2006

Possible relationship between adiponectin and renal tubular injury in diabetic nephropathy.

Adiponectin is an adipose-derived protein which has anti-inflammatory and anti-atherogenic properties in addition to insulin-sensitizing effects. To date, the role of adiponectin in the pathogenesis of diabetic nephropathy remains unclear. The aim of the present study was to explore the relationship between adiponectin and renal tubular injury in diabetic nephropathy. We determined serum and urinary adiponectin levels in type 2 diabetic patients with normoalbuminuria (n = 19), microalbuminuria (n = 18), and overt diabetic nephropathy (n = 16), and then analyzed the correlations between serum and urinary adiponectin, urinary N-acetylglucosaminidase (NAG) as a clinical marker of renal tubular injury, urinary monocyte chemoattractant protein-1 (MCP-1) as an inflammatory marker in renal tubulointerstitium, and clinical markers of renal disease. Notably, serum and urinary adiponectin levels were significantly increased in patients with overt diabetic nephropathy compared to those with normoalbuminuria and microalbuminuria. In univariate linear regression analysis, serum adiponectin levels were positively correlated with serum creatinine (r = 0.648, P<0.0001), urinary albumin (r = 0.583, P<0.0001), urinary NAG (r = 0.406, P<0.01), urinary MCP-1 (r = 0.514, P<0.0001), and urinary adiponectin (r = 0.691, P<0.0001) levels in all diabetic patients. Urinary adiponectin levels were also positively correlated with serum creatinine (r = 0.729, P<0.0001), urinary albumin (r = 0.799, P<0.0001), urinary NAG (r = 0.701, P<0.0001), and urinary MCP-1 (r = 0.801, P<0.0001) levels in all diabetic patients. Multiple linear regression analysis showed that serum creatinine and urinary adiponectin levels were independently associated with serum adiponectin levels (r(2) = 0.522), and that serum creatinine, urinary NAG, urinary MCP-1, and serum adiponectin levels were independent determinants of urinary adiponectin levels (r(2) = 0.851). These results collectively indicate that renal insufficiency and tubular injury possibly play a contributory role in increases in serum and urinary adiponectin levels in overt diabetic nephropathy. We presume that an increase in circulating adiponectin in overt diabetic nephropathy might be a physiological response to mitigate renal tubular injury and to prevent the further progression of diabetic nephropathy through its anti-inflammatory and anti-atherogenic effects.

Acetylglucosaminidase↗

PubMed2006

Roles of 11beta-hydroxysteroid dehydrogenase in fish spermatogenesis.

In fish spermatogenesis, the main action of progestins is generally regarded as the induction of sperm maturation. Our previous in vitro study demonstrated that a progestin, 17alpha,20beta-dihydroxy-4-pregnen-3-one (DHP), induced the initiation of meiosis in spermatogenesis in the Japanese eel (Anguilla japonica). In the present study, to elucidate the molecular mechanisms underlying the action of DHP, we attempted to clone cDNAs encoding genes whose expression was induced by DHP in eel testis, using cDNA subtraction. One of the cDNAs we isolated encodes eel 11beta-hydroxysteroid dehydrogenase short form (e11beta-HSDsf), and Northern blot and RT-PCR analysis showed that transcripts of e11beta-HSDsf in testis were induced by DHP. The recombinant e11beta-HSDsf had 11beta-dehydrogenase activity, metabolizing cortisol to cortisone, and 11beta-hydroxytestosterone to 11-ketotestosterone (11-KT). In vitro experiments revealed that eel immature testis had 11beta-dehydrogenase activity, and DHP treatment enhanced the activity. To understand the role of 11beta-HSD in spermatogenesis, we examined the direct effects of cortisol on eel spermatogenesis using an organ culture system. Cortisol induced DNA replication in spermatogonia and enhanced the spermatogonial proliferation induced by 11-KT. However, excess cortisol inhibited proliferation. In addition, 11-KT production was induced in testicular fragments incubated with cortisol. These results suggest that optimal levels of cortisol induced spermatogonial mitosis by increasing 11-KT production. Furthermore, two possible roles of DHP on spermatogenesis, via the up-regulation of 11beta-HSD expression, are suggested: positive feedback control of 11-KT production and the modulation of cortisol levels to protect testes from excess circulating cortisol.

11-beta-Hydroxysteroid Dehydrogenases↗

PubMed2006

Progestin is an essential factor for the initiation of the meiosis in spermatogenetic cells of the eel.

Meiosis is an indispensable process of sexual reproduction. However, detailed information on the regulatory mechanisms that initiate meiosis is not available. Progestins are important steroids regulating final maturation in male and female vertebrates. In male teleosts, it is known that progestin induces spermiation and sperm maturation. However, a role for progestin in early spermatogenesis or meiosis has not yet been described. In this study, we examined the functions of progestin on the initiation of meiosis in male Japanese eel. A natural progestin in teleost fish 17alpha,20beta-dihydroxy-4-pregnen-3-one (DHP) and its receptors were present in the testis at an early stage of spermatogenesis. By using an eel testicular culture system, DHP was shown to induce DNA replication in spermatogonia. Although 11-ketotestosterone, a known initiator of spermatogenesis, also stimulated DNA synthesis in spermatogonia, antibodies against DHP prevented DNA replication when added during the period in which meiosis was initiated. DHP treatment also induced the expression of meiosis-specific markers, such as DmcI and Spo11. Furthermore, Spo11 expression and synaptonemal complexes, specific features of the meiotic prophase, were detected in testicular fragments cultured with DHP in some germ cells that showed morphological characteristics of undifferentiated spermatogonia. We conclude that DHP, a progestin, is an essential factor for the initiation of meiosis.

Animals↗

PubMed2006

Systematic analysis of HSP gene expression and effects on cell growth and survival at high hydrostatic pressure in Saccharomyces cerevisiae.

We systematically investigated the role of HSP genes in the growth and survival of Saccharomyces cerevisiae under high hydrostatic pressure together with analysis of pressure-regulated gene expression. Cells of strain BY4742 were capable of growth at moderate pressure of 25 MPa. When pressure of 25 MPa was applied to the cells, the expression of HSP78, HSP104, and HSP10 was upregulated by about 3- to 4-fold, and that of HSP32, HSP42, and HSP82 was upregulated by about 2- to 2.6-fold. However, the loss of one of the six genes did not markedly affect growth at 25 MPa, while the loss of HSP31 impaired high-pressure growth. These results suggest that Hsp31 plays a role in high-pressure growth but that the six upregulated genes do not. Extremely high pressure of 125 MPa decreased the viability of the wild-type cells to 1% of the control level. Notably, the loss of HSP genes other than HSP31 enhanced the survival rate by about fivefold at 125 MPa, suggesting that the cellular defensive system against high pressure could be strengthened upon the loss of the HSP genes. In this paper, we describe the requirement for and significance of a subset of HSP genes in yeast cell growth at moderate pressure and survival at extremely high pressure.

Cell Proliferation↗

PubMed2006

Molecular cloning and gene expression of Spo11 during spermatogenesis in the Japanese eel, Anguilla japonica.

Spo11 is a protein involved specifically in the meiotic recombination in several species, however, it is little characterized in lower vertebrates. We identified a cDNA encoding Spo11 from the testis of Japanese eel, Anguilla japonica. The deduced amino acid sequence of eel Spo11 was more than 60% identical with human and mouse Spo11s. In order to examine changes in the expression and localization of Spo11 during spermatogenesis induced by the injection of human chorionic gonadotropin (hCG) and to compare with those of Dmc1, we generated specific antibodies against the eel Spo11 and Dmc1. In general, it is believed that Dmc1 is a meiosis-specific protein, and the localization of Dmc1 in spermatocytes was confirmed also in Japanese eel. Spo11 transcripts were slightly detected in the testis after 1 day post-hCG injection by Northern blot analysis. Western blot analysis also indicated that Spo11 production began at day 1 after hCG injection. However, immunohistochemical observations showed that Spo11 was localized only in spermatocytes. In contrast, Dmc1 transcripts and the protein production were first detected at day 6 after hCG injection and increased along with the increment of spermatocytes. These results suggested that Spo11 was expressed in spermatogonia proliferated toward meiosis at quite low level that could not induce meiotic recombination, thereafter Spo11 expression increased and Dmc1 expression was initiated in early meiotic prophase. Hence, the antibodies against eel Spo11 and Dmc1 generated in the present study can be use to detect germ cells in early meiotic prophase immunohistochemically. Importantly, it is suggested that germ cells, which are in quite earlier stage during meiotic prophase, can be detected by Spo11.

Adenosine Triphosphatases↗

PubMed2006

Characterization of cold- and high-pressure-active polygalacturonases from a deep-sea yeast, Cryptococcus liquefaciens strain N6.

A deep-sea yeast, Cryptococcus liquefaciens strain N6, produces two polygalacturonases, p36 and p40 (N6-PGases). These N6-PGases were highly active at 0-10 degrees C in comparison to a PGase from Aspergillus japonicus. The hydrolytic activity of these N6-PGases remained almost unchanged up to a hydrostatic pressure of 100 MPa at 24 degrees C with a very small activation volume of -1.1 ml/mol. At 10 degrees C, however, the activation volume increased to 3.3 or 5.4 ml/mol (p36 and p40, respectively), suggesting that the enzyme-substrate complexes can expand at their transition states. We speculate that such a volume expansion upon forming the enzyme-substrate complexes contributes to decreasing the activation energy for hydrolysis. This can account for the high activity of N6-PGases at low-temperature.

Cold Temperature↗

PubMed2005

Primary testicular leiomyosarcoma.

We report a case of primary testicular leiomyosarcoma. A 76-year-old man, who complained of left scrotal swelling for 6 months, underwent radical orchiectomy. Microscopic examination revealed intratesticular leiomyosarcoma. The patient received no adjuvant therapy and at 12 months after surgery, there had been no recurrence. Primary leiomyosarcoma of the testis is extremely rare; this is the 9th case recorded worldwide.

Aged↗

PubMed2005

[Comparison of value of free-to total prostate specific antigen, prostate specific antigen density and prostate specific antigen density of transition zone for diagnosis of prostate cancer in patients with a PSA level of 4.1-10 ng/ml].

PURPOSE: We evaluated the utility of free-to total PSA (F/T PSA) ratio, PSA density (PSAD) and PSA density of the transition zone (PSATZ) in diagnosis of prostate cancer with intermediate PSA level (4.1-10 ng/ml). PATIENTS AND METHODS: Between January 2000 and December 2003, systematic prostate biopsies were performed on 178 patients with intermediate PSA level. The clinical values of F/T PSA ratio, PSAD and PSATZ for the detection of prostate cancer were compared by using receiver operating characteristic (ROC) curves. RESULTS: Overall, 57 of the 178 (32%) patients had prostate carcinoma. The ROC curve analysis showed PSAD and PSATZ were superior to F/T PSA ratio in patients with intermediate PSA level. In patients with total prostate volume greater than 30 cm3, the area under the ROC curve for F/T PSA ratio was greater than that for PSAD and PSATZ. CONCLUSIONS: PSAD and PSATZ were more powerful predictors of prostate cancer than F/T PSA ratio in patients with intermediate PSA level. While F/T PSA ratio was effective for diagnosis of prostate cancer in prostate volume greater than 30 cm3.

Aged↗

PubMed2005

[A case of therapy-related leukemia/myelodysplastic syndrome following treatment of refractory testicular germ cell tumor].

We report a patient with a refractory testicular non-seminomatous germ cell tumor (NSGCT) who developed therapy-related leukemia (TRL) after undergoing salvage chemotherapy and multiple operations for repeat recurrences. Fifty months after the initial therapy, pancytopenia and myeloblasts were observed in the patient's peripheral blood while the patient was undergoing salvage chemotherapy for a fifth recurrence. A bone marrow examination showed evidence of myelodysplastic syndrome (MDS) and refractory anemia with excess of blasts in transformation (RAEB in T) under French-America-British (FAB) classification. Cytogenetic 5q-/7q- abnormalities were also observed. The patient had received a total dose of 189g/m2 of Ifosfamide, 8,250mg/m2 of Etoposide and 1,450 mg/m2 of Cisplatin; therefore, he was diagnosed as having TRL/MDS. The patient has received induction chemotherapy for TRL with Cytarabine, Daunorubicin and Fludarabine while a bone marrow transplantation has been scheduled. Recently, TRL associated with chemotherapy are being reported with increasing frequency in the literature. Since early detection and treatment are necessary for the management of TRL, peripheral blood examinations should be performed after a diagnosis of refractory germ cell tumor has been made. If pancytopenia is detected, bone marrow and cytogenetic examinations should be immediately performed to rule out TRL.

Adult↗

PubMed2005

[Combination chemotherapy with docetaxel and cisplatin in patients with hormone-refractory prostate cancer].

We investigated the efficacy of docetaxel and cisplatin for hormone-refractory prostate cancer (HRPC). Thirteen patients with HRPC were treated with 30 mg/m2 docetaxel weekly for 3 weeks and 70 mg/m2 cisplatin on day 1. Treatment was repeated every 21 days. They received 2 cycles and were evaluated for the responses to serum prostate-specific antigen (PSA) and tumor size. Ten (77%) of the 13 patients showed a 50% or greater decrease in PSA with a median time to progression of 3 months. One of the 2 patients with measurable soft tissue disease showed a reduction in disease. No severe toxicity of this regimen was observed. Combination chemotherapy with docetaxel and cisplatin in patients with HRPC was well tolerated and efficatious with a significant decrease in serum PSA and measurable disease.

Aged↗

PubMed2005

[Observation policy for residual masses after chemotherapy for gonadal and extra-gonadal germ cell tumors].

Twenty-five patients with germ cell tumors who had marker-free residual masses after undergoing chemotherapy were followed for up to 10 years (median, 21 months). The primary tumor sites were the gonads in 20 patients (6 seminomas [SGCTs] and 14 non-seminomatous germ cell tumors [NSGCTs]) and extra-gonadal regions in 5 patients (5 NSGCTs). All residual masses were observed in patients with SGCT. Residual masses that were 2 cm or less in size were left unresected, while masses that were 5 cm or more in size were resected in patients with NSGCT lesions. The management of other residual masses was decided based on the size, shrinkage, and pathological findings of the tumors. Residual masses were resected in six of the patients with gonadal NSGCTs. Recurrence occurred in one of the six patients with gonadal SGCTs (chemotherapy shrinkage; 11 cm to 3.5 cm) and three of the four cases with extra-gonadal NSGCTs (embryonal cell carcinoma: 3 cm to 1 cm, embryonal cell carcinoma+york sac tumor: 5 cm to 4 cm, embryonal cell carcinoma+chorio carcinoma; 4 cm to 1.2 cm). None of the patients with gonadal NSGCTs experienced a recurrence. Considering the pathologic diagnosis, shrinkage, and international germ cell consensus classification, unnecessary resections of residual masses that were less than 5 cm in size after chemotherapy for gonadal NSGCT should be avoided. However, residual masses in extra-gonadal NSGCTs should be resected.

Adult↗

PubMed2005

[Two cases of testicular cancer with low human chorionic gonadotropin (hCG) levels after treatment].

Some patients with testicular cancer exhibit low human chorionic gonadotropin (hCG) levels even after successful treatment. We report 2 patients with testicular cancer (2 non-seminomatous germ cell tumors [NSGCTs]) and low betahhCG levels with no recurrence after successful treatment. The first patient is a 45-year-old man with pulmonary and retroperitoneal lymph node metastases. During the first chemotherapy the hCG level decreased but remained at a low level. Salvage chemotherapy had no effect on the hCG level, but a low betahCG level persisted for 16 months. The second case is a 19-year-old man with testicular cancer with retroperitoneal lymph node metastases. The patient underwent an operation for residual masses after chemotherapy. Pathological findings showed necrotic tissue, and a low betahCG level persist for 160 months. A low hCG level does not necessarily meen residual malignancy. Patients with a low hCG level should be monaged carefully avoiding needless treatment.

Adult↗

PubMed2004

Multiple ubiquitin-specific protease genes are involved in degradation of yeast tryptophan permease Tat2 at high pressure.

When Saccharomyces cerevisiae cells are exposed to high hydrostatic pressure, tryptophan permease Tat2 is degraded in a manner dependent on Rsp5 ubiquitin ligase. Consequently, cell growth is arrested in tryptophan auxotrophic strains. Here we show that of 17 ubiquitin-specific protease genes (UBP), deletion of DOA4, UBP6 or UBP14 causes stabilization of Tat2 and hence the cells can grow at 25 MPa. These disruptant cells displayed marked sensitivity to the arginine analogue canavanine. Internal free ubiquitin decreased 2- to 5-fold upon UBP deletion, although overproduction of ubiquitin did not affect their high-pressure growth and canavanine sensitivity. These results suggest that multiple ubiquitin-specific proteases are involved in pressure-induced degradation of Tat2, rather than free ubiquitin depletion.

Amino Acid Transport Systems↗

PubMed2004

Ampulla (takotsubo) cardiomyopathy associated with subarachnoid hemorrhage worsening in the late phase of vasospasm--case report.

A 66-year-old woman presented with subarachnoid hemorrhage(SAH) caused by a ruptured aneurysm of the left middle cerebral artery. Electrocardiography (ECG) disclosed abnormalities resembling acute myocardial infarction. She underwent neck clipping of the aneurysm uneventfully. Sixteen days after admission, ECG again disclosed abnormalities resembling acute myocardial infarction, and echocardiography suggested heart failure. Coronary angiography showed no abnormalities, but left ventriculography showed severe hypokinesia in the apex of the heart consistent with so-called ampulla (takotsubo) cardiomyopathy. The heart failure was treated with catecholamines and her heart function gradually recovered. Ampulla (takotsubo) cardiomyopathy associated with SAH requires careful management of heart function.

Aged↗

PubMed2004

Parallel increase in urinary excretion rates of immunoglobulin G, ceruloplasmin, transferrin, and orosomucoid in normoalbuminuric type 2 diabetic patients.

OBJECTIVE: Increased urinary excretions of several plasma proteins with different molecular radii <55 A and different isoelectric points (pI), such as IgG, ceruloplasmin, transferrin, and orosomucoid, have been independently reported to precede the development of microalbuminuria in diabetic patients. We examined whether increases in urinary excretions of these proteins would be in parallel in the same patient. RESEARCH DESIGN AND METHODS: Urinary excretion rates of proteins mentioned above in timed overnight urine samples were evaluated in 61 normoalbuminuric type 2 diabetic patients (group D) aged 40-60 years and in 17 age-matched control subjects (group C). RESULTS: The excretion rates of these proteins were significantly higher in group D than in group C. These exhibited a strong linear correlation with each other and had a weak correlation with the excretion rate of N-acethylglucosaminidase. The excretion rate of alpha2-macroglobulin with large molecular radii of 88 A was not different between groups C and D, nor did they have any correlations with the excretion rates of the other proteins. Creatinine clearance and blood pressure levels in group D were significantly higher than those in group C. CONCLUSIONS: In normoalbuminuric diabetic patients, excretion rates of plasma proteins with molecular radii <55 A increased in parallel with each other. In view of our previous finding that urinary excretions of these plasma proteins selectively increased in parallel with enhanced glomerular filtration rate after acute protein loading, the present finding may be explained by renal hemodynamic changes, such as increased intraglomerular hydraulic pressure.

Adult↗

PubMed2004

[A case of well controlled renal small cell carcinoma with metastasis treated by intensive therapy].

A 18-year-old male visited hospital with macroscopic hematuria. Computed tomography showed slightly enhanced left renal tumor that was uncharacteristic for clear cell carcinoma, and radical nephrectomy was performed. Operative specimen revealed primary small cell carcinoma of the kidney. 18 months after operation, bone metastases were diagnosed. Chemotherapy including cisplatinum, etoposide and bleomycin and external irradiation was performed. This intensive therapy was effective for metastatic lesion. He is still alive for 55 months after diagnosis, and is the best controlled case around the world. To our knowledge, this is the 14th case as primary renal small cell carcinoma in the world literature.

Adolescent↗