Search PubMed⌕ Search

Biomedical subjects

Takumi Takeuchi

Publications and source records attributed to Takumi Takeuchi.

At least 19 recordsLinked to original sources
PubMed2007

Chronic acid ingestion promotes renal stone formation in rats treated with vitamin D3.

OBJECTIVE: Although hypercalciuria, a well-established adverse effect of vitamin D3, can be a risk factor of renal stone formation, the risk of nephrolithiasis has not been well defined. The consumption of a diet high in acid precursors is often cited as a risk factor for the development of calcium-based kidney stones. In the present study, we investigated the effect of chronic acid ingestion on kidney stone formation in rats treated with calcitriol (1-25[OH]2 D3). METHODS: Control rats (C-C), calcitriol-treated rats (C-V; three treatments of 0.5 microg of calcitriol per week) and acid-ingested (water containing 0.21 mol/L NH4Cl), calcitriol-treated (three treatments of 0.5 microg of calcitriol per week) rats (A-V) were fed in metabolic cages. After 1 month, urine, blood, kidney and bone samples were analyzed. RESULTS: The A-V rats exhibited elevated serum calcium concentrations, urinary calcium and phosphate excretion, urinary type I collagen cross-linked N-peptide (NTx)/creatinine values, mRNA expression of osteopontin in the kidney, and renal calcium contents as well as decreased bone mineral densities, compared with the C-C and C-V rats. Urinary citrate excretion was lower and NaDC-1 mRNA expression in the kidney was higher in the A-V rats than in the C-C and C-V rats. Calcium phosphate kidney stones were found in the A-V rats. CONCLUSIONS: The ingestion of NH4Cl, an acid precursor, promotes calcium phosphate kidney stone formation in calcitriol-treated rats. The chronic intake of a diet rich in acid precursors may be a risk factor for the development of kidney stones in subjects who are being treated with calcitriol.

Ammonium Chloride↗
PubMed2006

Laser-assisted blastocyst dissection and subsequent cultivation of embryonic stem cells in a serum/cell free culture system: applications and preliminary results in a murine model.

BACKGROUND: To evaluate embryonic stem cell (ESC) harvesting methods with an emphasis on derivation of ESC lines without feeder cells or sera. Using a murine model, laser-assisted blastocyst dissection was performed and compared to conventional immunosurgery to assess a novel laser application for inner cell mass (ICM) isolation. METHODS: Intact blastocysts or isolated ICMs generated in a standard mouse strain were plated in medium with or without serum to compare ESC harvesting efficiency. ESC derivation was also undertaken in a feeder cell-free culture system. RESULTS: Although ICM growth and dissociation was comparable irrespective of the media components, an enhanced ESC harvest was observed in our serum-free medium (p < 0.01). ESC harvest rate was not affected by ICM isolation technique but was attenuated in the feeder cell-free group. CONCLUSION: Achieving successful techniques for human ESC research is fundamentally dependent on preliminary work using experimental animals. In this study, all experimentally developed ESC lines manifested similar features to ESCs obtained from intact blastocysts in standard culture. Cell/sera free murine ESC harvest and propagation are feasible procedures for an embryology laboratory and await refinements for translation to human medical research.

Journal Article↗
PubMed2006

Bladder recurrence of upper urinary tract cancer after laparoscopic surgery.

PURPOSE: We reviewed our cases to determine whether laparoscopic nephroureterectomy is a risk factor for the bladder recurrence. MATERIALS AND METHODS: From 1996 to 2003, 65 nephroureterectomies were performed: 47 by open and 18 by laparoscopic surgery. In 43 (28 by open, 15 by laparoscopic surgery), bladder cancer was not observed at the time of the operation. Two laparoscopic operations were converted to open surgery because of technical problems. The other 13 with laparoscopic and 28 with open surgery were enrolled into this study. RESULTS: Significantly higher recurrence rate was observed in laparoscopic cases (69.2%) than that in open cases (35.7%, P = 0.0484) by log rank test. However, the operation time required in laparoscopic surgery (371.5 +/- 90.8 min) was significantly longer than that in the open surgery (229.9 +/- 46.6 min, P < 0.0001). In multivariate analysis (Cox proportional hazards model), only the longer operation time (>250 min) was a significant variable (P = 0.0305), and laparoscopic surgery in itself was not a significant risk factor (P = 0.5011). CONCLUSIONS: Although frequent bladder recurrence was observed in laparoscopic cases, the most important risk factor was the longer operation time. Technical improvements including shortening of operation time and earlier ureteral ligation may decrease the bladder recurrence.

Aged↗
PubMed2006

Tubulovillous adenoma developing after urinary reconstruction using ileal segments.

A case of tubulovillous adenoma arising in an augmented bladder is described. Ureteroileal substitution and ileocystoplasty was performed when the patient was 18 years old. She noticed gross hematuria 44 years after the surgery. Cystoscopy revealed a non-papillary multiple tumor at the site of ileovesical anastomosis and transurethral resection biopsy was performed. Histopathological examination revealed a tubulovillous adenoma. A tubulovillous adenoma developing at the augmented bladder is rare. To our knowledge, this is the second case in which a tubulovillous adenoma developed in an augmented bladder.

Adenoma, Villous↗
PubMed2006

Predictors of seminal vesicle invasion before radical prostatectomy.

AIM: To predict whether or not seminal vesicle invasion is present before radical prostatectomy, the relationships between clinical parameters and seminal vesicle invasion were analyzed. METHODS: A review was conducted of 187 patients who had been clinically diagnosed with stages A(2), B(0), B(1), B(2) or C prostate cancer and who had undergone radical prostatectomy without neoadjuvant therapy. The parameters analyzed for potential predictors of seminal vesicle invasion before radical prostatectomy included age, clinical stage, serum prostate-specific antigen (PSA) level at biopsy, tumor differentiation of biopsy specimens and percentage of cancer positive cores by biopsy. For percentage of cancer positive cores by biopsy, 143 of 187 patients who underwent transrectal sextant biopsy or more than six transrectal ultrasound guided core biopsies were evaluated. These parameters were subjected to univariate and multivariate logistic regression analyses to identify predictors for seminal vesicle invasion. RESULTS: The median age was 66.8 years (range 51-77 years). Of 187 patients, 27 (14.4%) had seminal vesicle invasion confirmed pathologically. There were significant differences in all parameters except for age between patients with positive and negative seminal vesicle invasion on univariate analysis. Multivariate analysis revealed that serum PSA level, tumor differentiation of biopsy specimens and percentage of cancer positive cores were significant independent predictors of seminal vesicle invasion. CONCLUSIONS: The results showed serum PSA level, tumor differentiation of biopsy specimens and percentage of cancer positive cores by biopsy before radical prostatectomy may be useful predictors for seminal vesicle invasion.

Aged↗
PubMed2006

Neutralization of interleukin-2 retards the growth of mouse renal cancer.

OBJECTIVE: To examine the significance of the thymus and the neutralization of interleukin-2 (IL-2) in treating renal cancer, as the involvement of immunoregulatory cells in tumour development in vivo is well known, naturally occurring CD25+ CD4+ T cells possess potent immunoregulatory functions, and they are of thymic origin dependent on IL-2. MATERIALS AND METHODS: We first tested activity against mouse renal cell carcinoma (RENCA) cells by adoptively transferring splenocytes of euthymic Balb/c mice depleted of CD25+ cells into athymic Balb/c nude mice bearing established macroscopic RENCA tumours. Second, we tested the anti-RENCA activity in euthymic mice bearing macroscopic RENCA tumours by neutralizing IL-2. RESULTS: The intravenous administration of CD25+ cell-depleted splenocytes of euthymic Balb/c mice initiated the retardation of macroscopic RENCA tumours subcutaneously established in athymic Balb/c mice. The tumour site showed massive lymphocyte infiltration of mainly CD4+ T cells. By eliminating either the CD4+ cells, CD8+ cells, or natural killer (NK) cells with antibodies after the adoptive transfer of CD25+ cell-depleted splenocytes of euthymic Balb/c mice, macroscopic RENCA tumour retardation was abrogated. The growth of macroscopic RENCA tumour established in euthymic Balb/c mice was also retarded with IL-2 neutralization alone by anti-IL-2 monoclonal antibody (mAb), as well as co-administration of anti-IL-2 mAb and anti-CD25 mAb compared with that of the controls given vehicle. After tumour inoculation, peri- and intratumoral infiltration of CD4+ and CD8+ T cells was very prominent in RENCA tumours in hosts given anti-IL-2 mAb, regardless of the administration of anti-CD25 mAb. Two x 10(5) units of recombinant human IL-2 reverted the retardation of RENCA tumour growth caused by the anti-IL-2 mAb. IL-2 neutralization alone in euthymic Balb/c mice with no tumour inoculation did not suppress splenic CD25+ CD4+ T cells. CONCLUSION: Both the intravenous administration of CD25+ cell-depleted splenocytes of euthymic Balb/c mice into athymic Balb/c nude mice and IL-2 blocking with anti-IL-2 mAb in euthymic Balb/c mice retarded the growth of macroscopic RENCA tumours in vivo.

Animals↗
PubMed2006

Extracellular matrix dermatopontin modulates prostate cell growth in vivo.

Dermatopontin is a tyrosine-rich acidic extracellular matrix protein of 22 kDa with possible functions in cell-matrix interactions and matrix assembly. We have previously isolated mRNAs expressed in hormone-refractory, but not in hormone-sensitive, mouse mammary cancer by comparing the mRNAs expressed in either tumor. A partial mRNA sequence isolated was later proven to be a part of mouse dermatopontin mRNA sequence. Transfectants of mouse dermatopontin cDNA into PC-3 human prostate cancer cells enhanced tumor growth when those were implanted subcutaneously in nude mice compared with the controls. Those transfectants showed a prominent stroma compared with the controls. Localization of the targets of a fusion protein of mouse dermatopontin and alkaline phosphatase was in the stroma of the PC-3 tumor tissues, but not in the tumor cells themselves. Additionally, we have established mouse dermatopontin transgenic mice under the control of the rat probasin promoter. The prostatic dorsal lobes of dermatopontin transgenic mouse showed prostate intra-epithelial neoplasia at the age of 11 months, but the control littermates did not. Epithelium of other prostatic lobes was not markedly different from that of the controls. In conclusion, dermatopontin may be involved in the pathogenesis and growth of the prostate cancer.

Animals↗
PubMed2006

Androgen receptor CAG polymorphism (Xq11-12) status and human spermatogenesis: a prospective analysis of infertile males and their offspring conceived by intracytoplasmic sperm injection.

We determined the association of androgen receptor (AR) (CAG)n lengths among fertile and infertile males and offspring conceived by intracytoplasmic sperm injection (ICSI). Assessment of (CAG)n repeats in the AR was performed in a Caucasian population by gene sequencing in fertile men (n=13), infertile men (n=64), boys conceived after ICSI (n=21), and boys conceived naturally (n=11). In the AZF region of the Y chromosome, a total of 22 STSs were analyzed by multiplex PCR; selected spermatozoa were also analyzed by fluorescent in situ hybridization (FISH) for chromosomes 18, 21, X, and Y. The average age was 43.7+/-7 yr for infertile, 44.8+/-7 yr for fertile men, and 5.0+/-0.5 yr for the children. The mean (CAG)n was 22.2+/-3 for the infertile men and 19.3+/-5 for fertile controls. There was a significant difference in CAG repeat length in the severely oligo-/azoo-spermic men vs. controls (p=0.02). An inverse correlation was evident between CAG length and semen parameters. For ICSI male children, the AR (CAG)n lengths were 21.4+/-3.2 vs. 20.8+/-3.4 for boys conceived naturally. While all peripheral karyotypes of fertile and infertile men were normal, de novo gonosomal abnormalities were observed in the ICSI offspring. The incidence of Y microdeletions was 1.6% in infertile men; all the ICSI sons had an intact Y chromosome. In conclusion, severely oligo- and azoospermic men had longer CAG repeat length than fertile controls, suggesting that certain AR gene mutations may have a negative effect on spermatogenesis. An increased incidence of de novo gonosomal abnormalities was found in the ICSI offspring when compared to children conceived naturally. Our assessment of the polymorphic region of the AR gene, in the absence of other specific genomic abnormalities, suggests that the fertility of children conceived by ICSI may be conserved.

Adult↗
PubMed2005

The Val158Met polymorphism of the catechol-O-methyltransferase gene is associated with the PSA-progression-free survival in prostate cancer patients treated with estramustine phosphate.

OBJECTIVE: The aim of our study is to find out the good responders for estramustine phosphate (EMP) therapy in patients with prostate cancer. We have focused on the metabolism of EMP and studied the association between a functional single-nucleotide polymorphism in the catechol-O-methyltransferase gene (Val158Met of COMT) and PSA-progression-free survival in Japanese patients with prostate cancer treated by EMP. METHODS: Seventy-two Japanese patients with previously untreated prostate cancer who were found to be eligible for low-dose EMP therapy were enrolled in the study. Genotyping of the Val158Met polymorphism of COMT was conducted by both the polymerase chain reaction-based restriction fragment length polymorphism method and TaqMan assay. RESULTS: Patients with the Val/Val genotype of COMT had a significantly higher PSA-progression-free rate as compared to those with the Val/Met or Met/Met genotype (p=0.027). The adjusted hazard ratio of biochemical PSA failure for the Val158Met genotype of COMT was 2.164 (95% CI, 1.111 to 5.525). CONCLUSIONS: The Val158Met polymorphism of COMT is associated with the PSA-progression-free rate of EMP-treated patients in prostate cancer.

Aged↗
PubMed2005

Identification and isolation of embryonic stem cells in reproductive endocrinology: theoretical protocols for conservation of human embryos derived from in vitro fertilization.

BACKGROUND: Embryonic stem cells (ESC) are pluripotent cells obtained from the inner cell mass (ICM) of blastocysts derived from in vitro culture associated with reproductive endocrinology therapy. Human ESCs are regarded as highly significant since they retain the capacity to differentiate into any of approximately 200 unique cell types. Human ESC research is controversial because to acquire such cells, the ICM of human blastocysts must be manipulated in a way that renders embryos nonviable and unsuitable for transfer in utero. Techniques to yield competent ESCs with conservation of source blastocysts would satisfy many objections against ESC research, but at present such approaches remain largely untested. RESULTS AND DISCUSSION: We contrast experimental culture of single blastomeres obtained by 1) non-destructive biopsy of embryos destined for transfer, and 2) isolation of karyotypically normal blastomeres from disaggregated ("dead") embryos considered unsuitable for transfer, and evaluate these approaches with regard to production of ESCs. Pluripotency was confirmed by morphological criteria and by quantification of divergent homeodomain proteins specific to undifferentiated cell development. Following ESC isolation and identification, assessment was conducted according to a novel ESC grading system, also proposed here. CONCLUSION: The role of reproductive endocrinology in ESC research remains paramount. In this report, we hypothesize new and expand on existing strategies having the potential to enhance human ESC isolation, identification and in vitro maintenance.

Animals↗
PubMed2005

Estrogen receptor-binding fragment-associated antigen 9 is a tumor-promoting and prognostic factor for renal cell carcinoma.

The estrogen receptor-binding fragment-associated antigen 9 (EBAG9) has been identified as a primary estrogen-responsive gene in human breast cancer MCF7 cells. A high expression of EBAG9 has been observed in invasive breast cancer and advanced prostate cancer, suggesting a tumor-promoting role of the protein in malignancies. Here we show that intratumoral (i.t.) administration of small interfering RNA against EBAG9 exerted overt regression of tumors following s.c. implantation of murine renal cell carcinoma (RCC) Renca cells. Overexpression of EBAG9 did not promote the proliferation of culture Renca cells; however, the inoculated Renca cells harboring EBAG9 (Renca-EBAG9) in BALB/c mice grew faster and developed larger tumors compared with Renca cells expressing vector alone (Renca-vector). After renal subcapsular implantation, Renca-EBAG9 tumors significantly enlarged compared with Renca-vector tumors in BALB/c mice, whereas both Renca-EBAG9 and Renca-vector tumors were developed with similar volumes in BALB/c nude mice. No apparent difference was observed in specific cytotoxic T-cell responses against Renca-EBAG9 and Renca-vector cells; nonetheless, the number of infiltrating CD8+ T lymphocytes was decreased in Renca-EBAG9 subcapsular tumors. Furthermore, immunohistochemical study of EBAG9 in 78 human RCC specimens showed that intense and diffuse cytoplasmic immunostaining was observed in 87% of the cases and positive EBAG9 immunoreactivity was closely correlated with poor prognosis of the patients. Multivariate analysis revealed that high EBAG9 expression was an independent prognostic predictor for disease-specific survival (P = 0.0485). Our results suggest that EBAG9 is a crucial regulator of tumor progression and a potential prognostic marker for RCC.

Adult↗
PubMed2005

Construction and fertilization of reconstituted human oocytes.

Construction of artificial gametes may be made possible by transferring somatic cells into enucleated oocytes and inducing chromosomal halving of their nuclei. This study examines the possibility of constructing viable human gametes, and their potential for participation in normal fertilization. Spare germinal vesicle-stage oocytes were donated by consenting patients undergoing intracytoplasmic sperm injection (ICSI). Approximately 62% of in-vitro matured oocytes survived enucleation and subsequent cumulus cell injection. Following micromanipulation and subsequent activation, about 40% of the reconstituted oocytes yielded two pronuclear-like entities. This was not accompanied by extrusion of a polar body, but resulted in the formation of two 'putative haploid' pronuclei. Therefore selective removal of a female pronucleus marker was required to restore a balanced ploidy. Male pronuclei were identified by association with sperm mitochondria. Additional pronuclei were then removed, allowing further cleavage. Zygotes derived were 'putatively haploid' in approximately 38% of cases with a limited number of chromosomes assessed. However, on karyotypic analysis, blastomeres isolated from cleaving embryos showed a chaotic distribution of chromosomes. Oocytes could induce 'putative haploidization' of transplanted somatic cell nuclei independently of donor cell gender. Fertilization of artificial oocytes was followed by embryonic cleavage despite blastocyst development and chromosomal content possibly being compromised.

Cell Culture Techniques↗
PubMed2005

Proteus syndrome with giant myelolipoma in the pelvis.

Proteus syndrome is a very rare and complex disorder with malformations and overgrowth of multiple tissues. This disorder was designated Proteus syndrome by Wiedemann et al. to denote its variable clinical expression. Our patient presented with macrodactyly, cerebriform appearance and a huge abdominal mass. A biopsy under laparotomy was performed, and histopathological examination revealed myelolipoma. Tumor resection was performed. To our knowledge, no case of Proteus syndrome presenting a myelolipoma in the retroperitoneal cavity has been reported before.

Humans↗
PubMed2004

Effect of treating induced mitochondrial damage on embryonic development and epigenesis.

Germinal vesicle transplantation (GVT) has been proposed as a possible treatment to correct age-related oocyte aneuploidy caused by dysfunctional ooplasm. How healthy ooplasm regulates normal meiosis and subsequent development has yet to be elucidated, but impaired mitochondrial metabolism may be attributable to incomplete segregation of the oocyte chromosomes. In the present study, after ooplasmic mitochondrial damage by photoirradiating chloromethyl-X-rosamine, examination of the oocyte nuclei's ability to survive after transfer into healthy ooplasts was performed. To assess their fertilizability and potential for development, GVT oocytes were fertilized by intracytoplasmic sperm injection (ICSI) and transferred to foster mice. Condition of the offspring at birth was assessed, and epigenetic analysis was performed. Photosensitization consistently inhibited oocyte maturation. However, after GVT of photosensitized nuclei into healthy ooplasts, 67.2% were reconstituted, and 76.2% of these matured normally, with an overall rate of 51.2%, much higher than that (6.0%) in the mitochondrially injured oocytes. After ICSI, 65.8% (52/79) of GVT oocytes were fertilized normally, and 21.1% (11/52) eventually reached the blastocyst stage. The transfer of 132 two-cell GVT embryos into the oviducts of pseudopregnant females resulted in 17 apparently healthy live offspring. For some key developmental genes, a high level of expression was identified in the GVT and "rescue"-derived fetal adnexa. Thus, one can induce in oocyte mitochondria a photosensitization-based type of damage, which consistently inhibits GV breakdown, meiotic spindle formation, chromosomal segregation, and polar body extrusion. Germinal vesicle transplanted and rescued oocytes were able to undergo maturation, fertilization, and embryonic cleavage and, ultimately, to develop to term. This approach may provide a model with which to study the age-related ooplasmic dysfunction seen in human oocytes.

Animals↗
PubMed2004

Embryo development after heterotopic transplantation of cryopreserved ovarian tissue.

BACKGROUND: Cancer treatments, including chemotherapy, radiotherapy, and radical surgery, can induce premature menopause and infertility in hundreds of thousands of women of reproductive age every year. One of the ways to possibly preserve fertility before these treatments is to cryopreserve ovarian tissue for later transplantation. We aimed to restore fertility by cryopreservation and transplantation of ovarian tissue. METHODS: Ovarian tissue was cryopreserved from a 30-year-old woman with breast cancer before chemotherapy-induced menopause, and this tissue was transplanted beneath the skin of her abdomen 6 years later. FINDINGS: Ovarian function returned in the patient 3 months after transplantation, as shown by follicle development and oestrogen production. The patient underwent eight oocyte retrievals percutaneously and 20 oocytes were retrieved. Of the eight oocytes suitable for in-vitro fertilisation, one fertilised normally and developed into a four-cell embryo. INTERPRETATION: Fertility and ovarian endocrine function can be preserved in women by long-term ovarian tissue banking.

Abdominal Wall↗
PubMed2004

A successful model to assess embryo development after transplantation of prophase nuclei.

BACKGROUND: Germinal vesicle transplantation (GVT) provides a means of investigating interactions between karyoplasts and cytoplasts isolated from different cells. Technically, GVT can be accomplished with a high degree of efficiency without compromising the maturation of either the human or mouse oocyte nucleus. Although maturation, fertilization and preimplantation development have been established using GVT, full-term development has been reported only after supplementation with fresh mature ooplasm. In this study, we assess the ability of immature oocytes collected from gonadotrophin-primed ovaries to mature in vitro after GVT and develop to full-term. METHODS: GV oocytes were retrieved from either non-stimulated or pregnant mare's serum gonadotrophin (PMSG)-primed female mice. Microsurgically isolated GV karyoplasts were transplanted into previously enucleated oocytes. Oocytes successfully reconstituted by electrofusion were cultured for 14 h to allow nuclear maturation. Metaphase II oocytes were subjected to Piezo-ICSI, and those fertilized normally were cultured to the blastocyst stage. Some such embryos were transferred to pseudopregnant female mice to examine their potential for normal development. Cumulus-denuded non-manipulated oocytes that were matured in vitro served as controls. RESULTS: The reconstitution and maturation rates were comparable in oocytes isolated from PMSG-primed and from unstimulated ovaries. The rate of normal fertilization in oocytes from primed ovaries was significantly higher than that of their non-primed counterparts (63.5 versus 39.6%; P < 0.01). This difference was also confirmed in terms of blastocyst development (31.8 versus 7.9%; P < 0.01). Of a total of 70 embryos transferred to the oviduct of five recipient mice, 21.4% developed to normal live offspring. All developed as normal adults and proved to be fertile. The live birth rate was comparable to that obtained using non-manipulated control oocytes (22.3%). CONCLUSIONS: Higher rates of fertilization and blastocyst formation were obtained after GVT of mouse oocytes isolated from PMSG-primed ovaries compared with their non-primed counterparts. These represent the first mouse offspring derived from in vitro matured, cumulus-denuded oocytes treated by allo-GVT and fertilized by ICSI. Thus, GVT appears not to impair oocyte maturation, fertilization and pre- and post-implantation development and, after gonadotrophin priming, allows generation of healthy mouse offspring without mature ooplasm supplementation.

Animals↗