Search PubMed⌕ Search

Biomedical subjects

Toshiaki Tanaka

Publications and source records attributed to Toshiaki Tanaka.

At least 91 records · Page 5Linked to original sources
PubMed2003

A case of Turner syndrome with congenital hypothyroidism untreated until age 38 years.

OBJECTIVE AND METHODS: The effect of thyroid hormone on human growth and maturation is considered 'permissive'. To evaluate the effect of a prolonged thyroid hormone defect, especially in the pubertal period, a woman with untreated congenital hypothyroidism underwent studies of thyroid function and bone maturation for the first time at age 38 years 10 months and received thyroid hormone replacement. RESULTS: The karyotype was 45,X/46,XX. Menstruation had occurred for 10 years, from menarche until she was about 31 years old. Epiphyseal closure of the left hand was incomplete. The serum thyroid hormone level was virtually undetectable, and her thyroid gland was not detectable in the normal position by ultrasonography. Her height increased by 3.5 cm in the first 9 months after starting thyroid hormone replacement; after 11 months, closure of the epiphysis was complete. CONCLUSION: Thyroid hormone is necessary to achieve bone maturation and epiphyseal closure, but its role is only permissive.

Adult↗
PubMed2003

Adjuvant chemotherapy after radical resection of squamous cell carcinoma in the thoracic esophagus: who benefits? A retrospective study.

BACKGROUND: A definitive combined modality therapy superior to surgery alone has not yet been found for esophageal cancer. This retrospective study investigated the impact of postoperative adjuvant chemotherapy in patients who underwent curative (R0) esophagectomy with radical lymphadenectomy. STUDY DESIGN: Two hundred and eleven patients with a squamous cell carcinoma in the thoracic esophagus who underwent transthoracic curative (R0) esophagectomy with radical lymphadenectomy, such as 3-field lymphadenectomy or total 2-field lymphadenectomy, between 1988 and 2000, were retrospectively reviewed. Ninety-four patients received postoperative chemotherapy - 2 courses of cisplatin (CDDP) plus fluorouracil (5-FU) or vindesine (VDS) - while the other 117 patients received surgery alone. The overall survival rate was compared between the two groups after being stratified by the numbers of the metastasis- positive lymph nodes. RESULTS: Only in the subgroup of patients with 8 or more lymph nodes metastasis- positive, the surgery-with-postoperative-chemotherapy group had a significantly better survival than the surgery-alone group. No significant difference was found in survival between the two groups in any other stratified subgroup. CONCLUSIONS: Postoperative adjuvant chemotherapy following curative (R0) esophagectomy with radical lymphadenectomy such as 3-field lymphadenectomy or total 2-field lymphadenectomy provided a benefit only in patients having metastasis in a large number - 8 or more - lymph nodes.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2003

In vivo analysis of the cyclin D1 promoter during early embryogenesis in Xenopus.

Cyclin D1 plays an important role in the regulation of G1 progression of the somatic cell cycle by functioning as a regulatory subunit of cdk4 and 6. Since both cyclin D1-mRNA and -protein turn over very rapidly, the expression of cyclin D1 is mostly regulated at the transcription level. Detection of the cyclin D1-specific mRNA during early embryogenesis in Xenopus laevis revealed that expression was induced soon after the midblastula stage but not during the cleavage stage, and was mainly found in the neural plate and eye vesicles. The recently-developed transgenic frog technique enabled us to analyze the frog cyclin D1 promoter activity in vivo by using green fluorescent protein (GFP) as a marker. During early embryogenesis, a GFP signal was detected at the neural plate in the neurula of the transgenic embryos. Transgenic analysis using sequential-deletion and point mutants of the cyclin D1 promoter revealed that a single, putative TCF/LEF binding site, located approximately 3.5 kb upstream of the transcriptional initiation site, was required for neural plate-specific expression. Our results suggest that the TCF/LEF signaling pathway participates in the regulation of cyclin D1 induction during the generation of the dorsal nervous system in early frog embryogenesis.

Amino Acid Motifs↗
PubMed2003

Dominant negative E2F inhibits progression of the cell cycle after the midblastula transition in Xenopus.

The cleavage cycle, which is initiated by fertilization, consists of only S and M phases, and the gap phases (G1 and G2) appear after the midblastula transition (MBT) in the African clawed frog, Xenopus laevis. During early development in Xenopus, we examined the E2F activity, which controls transition from the G1 to S phase in the somatic cell cycle. Gel retardation and transactivation assays revealed that, although the E2F protein was constantly present throughout early development, the E2F transactivation activity was induced in a stage-specific manner, that is, low before MBT and rapidly increased after MBT. Introduction of the recombinant dominant negative E2F (dnE2F), but not the control, protein into the 2-cell stage embryos specifically suppressed E2F activation after MBT. Cells in dnE2F-injected embryos appeared normal before MBT, but ceased to proliferate and eventually died at the gastrula. These cells contained decreased cdk activity with enhanced inhibitory phosphorylation of Cdc2 at Tyr15. Thus, E2F activity is required for cell cycle progression and cell viability after MBT, but not essential for MBT transition and developmental progression during the cleavage stage.

Animals↗
PubMed2003

The comparison of the effects of short-term growth hormone treatment in patients with achondroplasia and with hypochondroplasia.

The effects of recombinant human growth hormone (rhGH) treatment for three years were compared in patients with achondroplasia (ACH) and hypochondroplasia (HCH), whose diagnosis had been confirmed by DNA analysis of the fibroblast growth factor receptor 3 gene. Height SDS (H-SDS) and height velocity SDS (HV-SDS) using the standard for ACH significantly improved during three-year treatment as compared with that before treatment in both ACH and HCH except HV-SDS in the third year. The improvement was much greater in HCH than in ACH. The mean increase H-SDS using the standard for ACH in three years in ACH (from -0.2 SD to 0.1 SD) is almost negligible but that in HCH (from 1.2 SD to 2.6 SD) can be estimated as effective clinically. It can be concluded short-term GH treatment in HCH is effective to increase growth rate and H-SDS, but it has little effect in ACH. Further studies would be required to confirm the other beneficial effects of GH treatment such as increase in bone mineral density in ACH and HCH and the effect on the final height.

Achondroplasia↗
PubMed2003

[Chemoradiotherapy for esophageal cancer].

Since mucosal (T1a) esophageal cancer is well controlled by endoscopic treatment, chemoradiotherapy (CRTx) is not indicated. However, for a submucosal (T1b, N0) esophageal cancer, CRTx may be the first line of treatment, since it can provide a good response rate, with an excellent survival rate comparable to that after esophagectomy. Definitive CRTx is also in the first line of treatment for a T4 esophageal cancer, because there was no difference in the survival rate between CRTx with surgery and CRTx without surgery in our trial. Esophagectomy is indicated only for non-responders or recurrence-salvage surgery. For patients with a potentially-resectable (T2-T3) esophageal cancer, esophagectomy offered a longer survival rate than CRTx did, in our series. However, there remains controversy over the efficacy of CRTx for a T2-T3 esophageal cancer. It has been reported by the National Cancer Center Hospital East Group that definitive CRTx provided the same survival rate as esophagectomy. A prospective trial comparing the survival rate after esophagectomy and that after CRTx for a T2-T3 esophageal cancer is needed.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2003

Bystander effect in suicide gene therapy is directly proportional to the degree of gap junctional intercellular communication in esophageal cancer.

Gap junctional intercellular communication (GJIC) has been shown to be involved in the bystander effect through herpes simplex virus thymidine kinase/ganciclovir (HSV-tk/GCV) gene therapy. In this study, we examined the expression of connexins, the components of gap junction, and the degree of GJIC in esophageal cancer cell lines and compared the bystander effect in cells with different capacities of GJIC. We found loss in connexin 26 expression and reduced connexin 43 in esophageal cancer. GJIC capacity varied among cell lines and was dependent on the connexin 43 expression in the cell-cell contact areas. In mixing assay, the extent of the bystander effect was tightly correlated with the degree of GJIC capacity. The effects of retinoic acid and cAMP on the bystander effect were also investigated. Treatment with retinoic acid, but not with cAMP, was associated with augmented bystander killing by increase in GJIC in some esophageal cancer cell lines. Our results indicated that the degree of GJIC was predictive to identify a tumor as suitable for gene therapy with the HSV-tk/GCV system. Also GJIC chemically-enhanced with retinoic acid might be useful to improve response in suicide gene therapy.

Blotting, Western↗
PubMed2003

[Preliminary evaluation of chemotherapy with docetaxel, 5-FU, CDDP for recurrent esophageal cancer--a pilot study].

A pilot study has been conducted since January 2002 to investigate whether chemotherapy with docetaxel, 5-FU, CDDP could be an effective regimen for recurrent esophageal cancer. Ten patients with recurrent esophageal cancer were treated with the combination of docetaxel 60 mg/m2 (day 1), CDDP 10 mg/body (days 1-5) and 5-FU 500 mg/body (days 1-5) at intervals of 2-3 weeks. All patients had undergone surgery, had a recurrent tumor and had already been treated with chemo-radiotherapy or chemotherapy with CDDP + 5-FU. Response evaluation in 10 patients with measurable disease: partial response 4 patients, stable disease 2 patients and progressive disease 4 patients. The main NCI-CT grade 3/4 toxicity was leukopenia (8/10). Mild to moderate nausea (> or = grade 2) occurred in 3/10 patients.

Aged↗
PubMed2003

[Growth Hormone (GH) treatment in GH deficient children].

Bone mineral density (BMD) is reduced in children with growth hormone deficiency. Long-term GH therapy has been shown to increase BMD and levels of biochemical markers of bone turnovre. Adequate GH replacement therapy should be performed, starting as early as possible and optimizing treatment with adequate dose to achieve normal BMD at the time of reaching final height.

English Abstract↗
PubMed2002

Monitoring of exocytosis and endocytosis of insulin secretory granules in the pancreatic beta-cell line MIN6 using pH-sensitive green fluorescent protein (pHluorin) and confocal laser microscopy.

The dynamics of exocytosis/endocytosis of insulin secretory granules in pancreatic beta-cells remains to be clarified. In the present study, we visualized and analysed the motion of insulin secretory granules in MIN6 cells using pH-sensitive green fluorescent protein (pHluorin) fused to either insulin or the vesicle membrane protein, phogrin. In order to monitor insulin exocytosis, pHluorin, which is brightly fluorescent at approximately pH 7.4, but not at approximately pH 5.0, was attached to the C-terminus of insulin. To monitor the motion of insulin secretory granules throughout exocytosis/endocytosis, pHluorin was inserted between the third and fourth amino acids after the identified signal-peptide cleavage site of rat phogrin cDNA. Using this method of cDNA construction, pHluorin was located in the vesicle lumen, which may enable discrimination of the unfused acidic secretory granules from the fused neutralized ones. In MIN6 cells expressing insulin-pHluorin, time-lapse confocal laser scanning microscopy (5 or 10 s intervals) revealed the appearance of fluorescent spots by depolarization after stimulation with 50 mM KCl and 22 mM glucose. The number of these spots in the image at the indicated times was counted and found to be consistent with the results of insulin release measured by RIA during the time course. In MIN6 cells expressing phogrin-pHluorin, data showed that fluorescent spots appeared following high KCl stimulation and remained stationary for a while, moved on the plasma membrane and then disappeared. Thus we demonstrate the visualized motion of insulin granule exocytosis/endocytosis using the pH-sensitive marker, pHluorin.

Animals↗
PubMed2002

Antipruritic activity of the kappa-opioid receptor agonist, TRK-820.

The effects of the kappa-opioid receptor agonist, TRK-820, (-)-17-(cyclopropylmethyl)-3, 14beta-dihydroxy-4, 5alpha-epoxy-6beta-[N-methyl-trans-3-(3-furyl) acrylamido] morphinan hydrochloride, on the itch sensation were compared with those of histamine H1 receptor antagonists, using the mouse pruritogen-induced scratching model. Peroral administration of TRK-820 reduced the numbers of substance P- or histamine-induced scratches dose dependently. No obvious suppression of the spontaneous locomotor activity was observed at the doses used for the experiments, indicating that the inhibition of scratches was not due to the effect on general behavior. Furthermore, the scratching inhibitory activity of TRK-820 was dose dependently antagonized by the specific kappa-opioid receptor antagonist, nor-binaltorphimine, suggesting that the inhibitory activity was mediated via kappa-opioid receptors. Histamine H1 receptor antagonists, chlorpheniramine and ketotifen, did not inhibit substance P-induced scratches, or did so only partially. Both antihistamines inhibited the histamine-induced scratches completely. These results suggest that TRK-820 has antipruritic activity which is mediated by kappa-opioid receptors, and is effective in both antihistamine-sensitive and -resistant pruritus.

Animals↗
PubMed2002

Production of soluble integrin alpha2beta1 heterodimer complex functionally active in vitro and in vivo.

Integrin alpha2beta1, which is a membrane protein consisting of noncovalently bound alpha2 and beta1 chains, mediates cell binding to collagen and plays a role in platelet functions. DNAs encoding the chimeric proteins in which the extracellular domains of each alpha2 and beta1 chain was fused to hinge and Fc regions of human IgG(1)gamma chain were cotransfected into CHO cells. Soluble integrin alpha2beta1 (salpha2beta1) in which alpha2 and beta1 chains were covalently bound by disulfide bonds was recovered from the culture supernatant. salpha2beta1 maintained functional characteristics of cell surface alpha2beta1 as indicated by cation-dependent binding to collagen and conformational changes induced by cations or ligand. Intravenously administered salpha2beta1 in rats colocalized with collagen in inflamed microvessels. Moreover, salpha2beta1-conjugated liposome administered intravenously reduced bleeding time of the thrombocytopenic mice. These results indicated that salpha2beta1 has pharmaceutical utilities as an agent for detecting injured vessels and a component of platelet substitute.

Animals↗
PubMed2002

Locoregional adoptive immunotherapy resulted in regression in distant metastases of a recurrent esophageal cancer.

Esophageal cancer is one of the most common malignant diseases. However, postoperative recurrences are still resistant to currently available radiochemotherapy. We recently reported a study on the initial clinical efficacy of locoregional adoptive immunotherapy for advanced esophageal cancer. We report here our clinical experience of remarked responses in distant metastatic lesions in a patient with recurrent cancer after receiving this immunotherapy. A male patient underwent curative surgery, and presented with multiple recurrent metastases in the supraclavicular lymph nodes (LNs), liver, and abdominal aortic LNs. Autologous tumor-activated lymphocytes (AuTLs) generated ex vivo were regionally injected into supraclavicular LNs every 2 weeks 13 times. Mean numbers of the administrated cells were 0.8 x 10(9) cells/injection. AuTLs established from peripheral blood lymphocytes stimulated by autologous tumor cells with interleukin-2 were tested for their cytotoxicity before every treatment. During immunotherapy, Grade 2 diarrhea and fever were observed. The clinical partial responses were obtained in all lesions and were sustained for 11 months. Because clinical toxicity was tolerable, this immunotherapy might be useful for patients with far-advanced esophageal cancers.

Antigens, CD↗
PubMed2002

Compound heterozygous mutations in the cholesterol side-chain cleavage enzyme gene (CYP11A) cause congenital adrenal insufficiency in humans.

Cholesterol side-chain cleavage enzyme (P450scc) catalyzes the conversion of cholesterol to pregnenolone in mitochondria, which is the first step in the biosynthesis of all steroid hormones. Until now, no homozygous or compound heterozygous mutations in CYP11A have been described in humans. Here we describe novel compound heterozygous mutations in CYP11A in a patient with congenital adrenal insufficiency born to healthy parents. One mutation, a maternally inherited R353W mutation, resulted in markedly reduced P450scc activity by the single amino acid substitution, indicating that Arg(353) is a crucial amino acid residue for P450scc activity. The other mutation, a de novo A189V mutation in the paternal allele, did not affect the P450scc activity by the single amino acid substitution and turned out to be a splicing mutation, which created a novel alternative splice-donor site. It resulted in a deletion of 61 nucleotides in the open reading frame and thus partially inactivated CYP11A. These experimental data are consistent with the clinical findings indicating that the patient had partially preserved ability to synthesize adrenal steroid hormones. This is the first report of the compound heterozygote for the CYP11A mutations with congenital adrenal insufficiency and the phenotypically normal heterozygote in humans.

Adrenal Glands↗
PubMed2002

Analysis of the AAAS gene in a Japanese patient with triple A syndrome.

Triple A syndrome, also known as Allgrove syndrome, is a rare autosomal recessive disorder characterized by adrenal insufficiency, achalasia and alacrima. It has recently been reported that this syndrome is caused by mutations in the AAAS gene. In the present study, we analyzed the AAAS gene in a Japanese patient with triple A syndrome. The patient was a Japanese girl previously reported by Hirose et al. (J Jpn Pediatr Soc 102: 912-915, 1998). The parents of the patient were first cousins. The patient was confirmed to have alacrima and isolated glucocorticoid deficiency at the age of 2 years. She later developed achalasia of the cardia, and was diagnosed as having triple A syndrome. The AAAS gene was amplified by the PCR method, and the PCR products were directly sequenced. The patient was homozygous for a novel nonsense mutation Q237X, changing codon 237 encoding Gln (CAA) to a stop codon (TAA). The parents were heterozygous for the Q237X mutation. The AAAS gene encodes a protein of 546 amino acids, ALADIN. The Q237X mutation is predicted to result in a truncated and presumably non-functioning ALADIN protein, thus causing the clinically manifest syndrome in the patient. To our knowledge, this is the first report on AAAS gene mutations in Japan.

Adrenal Insufficiency↗