Search PubMed⌕ Search

Biomedical subjects

T Yanase

Publications and source records attributed to T Yanase.

At least 37 records · Page 2Linked to original sources
PubMed2000

Insulin sensitizer, troglitazone, directly inhibits aromatase activity in human ovarian granulosa cells.

Ovarian granulosa cells synthesize estrogens from androgens, which are catalyzed by aromatase cytochrome P450 (P450arom). Troglitazone (Tro), one of the insulin-sensitizing compounds, thiazolidinediones (TZDs), is a ligand for peroxisome proliferator activated receptor gamma (PPARgamma) and is effective in the treatment of both non-insulin-dependent diabetes mellitus (NIDDM) as well as polycystic ovary syndrome (PCOS). PPARgamma exerts a transcriptional activity as a PPARgamma:RXR heterodimer. In this study, we investigated the effects of Tro and/or RXR ligand, LG100268 (LG) on the aromatase activity in cultured human ovarian granulosa cells obtained from patients who underwent in vitro fertilization. Human ovarian granulosa cells expressed PPARgamma mRNA assessed by RT-PCR. The treatment of the granulosa cells with Tro for 24 h resulted in a dramatic inhibition of the aromatase activity in a dose-dependent manner. While the treatment with LG alone also inhibited the aromatase activity, the combined treatment with both Tro and LG caused a much more reduction in the aromatase activity. The changes in the aromatase activity by Tro and/or LG were associated with comparable changes in P450arom mRNA assessed by RT-PCR. These results suggest that Tro directly inhibit the aromatase activity in human granulosa cells probably via nuclear receptor system PPARgamma:RXR heterodimer. The findings may provide a biochemical basis for the decrease in the blood concentrations of estrogens which is observed after the in vivo administration of Tro and may also possibly be useful as a novel therapy for estrogen-dependent diseases.

Adult↗
PubMed2000

Suppression of paraquat-induced wet dog shakes by nitric oxide synthase inhibitors in rats.

We have found that paraquat (PQ), a widely used herbicide, causes wet dog shakes (WDS), which involve the central opioid system, in rats. A non-selective nitric oxide (NO) synthase (NOS) inhibitor, N(omega)-nitro-L-arginine (L-NA), but not its less active enantiomer, N(omega)-nitro-D-arginine, decreased the PQ-induced WDS in a dose-related manner. A selective neuronal NOS inhibitor in vivo, 7-nitroindazole, also decreased the PQ-induced WDS. Although an opioid receptor antagonist, naloxone, reversed the suppressive effect of these NOS inhibitors on the PQ-induced WDS, L-arginine, an NO precursor, had no effect on it. These findings suggest that the suppression of the PQ-induced WDS by NOS inhibition is associated with the central opioid system and is insusceptible to exogenous L-arginine.

Animals↗
PubMed2000

Induction of endometrial cycles and ovulation in a woman with combined 17alpha-hydroxylase/17,20-lyase deficiency due to compound heterozygous mutations on the p45017alpha gene.

OBJECTIVE: To describe the case of a Japanese woman with combined 17alpha-hydroxylase/17,20-lyase deficiency (congenital adrenal hyperplasia type V) and to discuss possible therapeutic procedures in such patients. DESIGN: Case report. SETTING: University hospital. PATIENT(S): A 26-year-old woman with secondary amenorrhea and primary sterility. INTERVENTION(S): Nucleotide sequencing of the P45017alpha gene (CYP17), induction of endometrial maturation with steroid hormone replacement, and ovulation induction with gonadotropin. MAIN OUTCOME MEASURE(S): Nucleotide sequence of CYP17, endometrial thickness and follicle diameter measured by transvaginal ultrasonography, and histologic evaluation of the endometrium. RESULT(S): Two different mutations were detected on CYP17: One was a deletion of the phenylalanine codon (TTC) at either amino acid 53 or 54 in exon 1, and the other was a missense mutation with the substitution of histidine (CAC) by leucine (CTC) at position 373 in exon 6. Repeated histologic evaluations performed during treatment with P consistently revealed an unripe endometrium with glands of the early secretory phase and markedly scanty stroma. Ultrasound examination revealed follicular growth and ovulation after gonadotropin administration, but insufficient thickness of the endometrium. CONCLUSION(S): Ovulation induction was possible in this patient with 17alpha-hydroxylase/17,20-lyase deficiency, but the endometrial response to steroid hormone replacement was extremely poor.

Adrenal Hyperplasia, Congenital↗
PubMed2000

Thiazolidinedione suppresses the expression of erythroid phenotype in erythroleukemia cell line K562.

The activation of PPARgamma:RXR nuclear system induces monocytic differentiation of some myelogeneous leukemia cell lines. The present study was undertaken to examine the effect of PPARgamma ligand, TZD (troglitazone or pioglitazone) and/or RXR selective ligand, LG100268 on the erythroleukaemia cell line K562 which has both an erythroid character and a potential for differentiation into megakaryocytes. TZD suppressed cell proliferation and the erythroid phenotype of K562 cells. The suppression of erythroid phenotype of K562 cells by TZD was synergistically enhanced by the combined treatment with LG100268. Moreover, the marked suppression of erythroid phenotype in K562 cells was also accompanied by the downregulation of the erythroid lineage-transcription factor, GATA-1. These novel actions of troglitazone may provide a biochemical basis for anemia occasionally which is observed after the in vivo administration of TZD.

Cell Differentiation↗
PubMed2000

Identification of insertion and deletion genes in Autographa californica nucleopolyhedrovirus variants isolated from Galleria mellonella, Spodoptera exigua, Spodoptera litura and Xestia c-nigrum.

The genomic DNA of four Autographa californica multinucleocapsid nucleopolyhedrovirus (AcMNPV) variants isolated from Galleria mellonella, Spodoptera exigua, Spodoptera litura and Xestia c-nigrum was analyzed in comparison with the AcMNPV E2 strain. Restriction endonuclease analysis revealed a deletion and an insertion in collinear regions of the four variants. Polymerase chain reaction analysis indicated that, in the four variants, the deletion occurred in the region corresponding to AcMNPV C6 ORF86 (pnk/pnl). Also the insertion, with a length of approximately 1.1 kb, was commonly identified in the fragments corresponding to the PstI-J fragment (18.5 m.u.-21.2 m.u.) of AcMNPV E2. Sequencing analysis of the variant from S. litura showed that the insertion contains an additional open reading frame encoding 322 amino acids between homologues of AcMNPV ORF30 and ORF31 (the superoxide dismutase gene). This ORF has 82.8% amino acid identity to Bombyx mori NPV T3 ORF 22 (bro-a, one of the baculovirus repeated ORFs) and thus, it was named Splt-bro-a. Southern blot hybridization study indicated that the other three variants also contain Splt-bro-a homologue. In addition, the labeled Splt-bro-a gene weakly hybridized to the PstI-D fragment (99.0 m.u.-8.0 m.u.) of AcMNPV E2. This fragment contains AcMNPV ORF2, a member of bro family. The signal was also observed on the corresponding fragment of the four variants. This result suggested that two bro genes are present in the four variants, although AcMNPV E2 and C6 are known to contain a single bro gene.

Amino Acid Sequence↗
PubMed2000

A case of fever of unknown origin with severe stomatitis in renal transplant recipient resulting in graft loss.

We present a case of fever of unknown origin and life-threatening stomatitis developed about 60 months after renal transplantation. He was 15 yr old at the transplantation. Bacterial, fungal, and viral infections were not evident. Fever and stomatitis were resistant to acyclovir and to any anti-bacterial or anti-fungal treatment. Graft biopsy revealed a small focus of acute vascular rejection, but the findings were not severe enough to be an etiology of the fever in this case. The administration of cyclosporine (CYA) was stopped 19 d before graftectomy, but the clinical picture was unchanged. Fever and stomatitis was resolved immediately after graftectomy and the discontinuation of immunosuppressants such as mizoribine (MZ) and prednisolone. Pathological changes of the graft included chronic transplant glomerulopathy, acute glomerulitis, and lymphocyte infiltration in peritubular capillaries. Thus we suppose that immunosuppressants were the cause of both fever and stomatitis in this case. We speculate that a fever in this case might be due to the immunosuppressant itself, i.e., CYA or MZ, or viral infection probably herpes-simplex virus infection. It is probably the immunosuppressive state per se that may cause the resistance of his muco-cutaneous lesion to anti-viral agent.

Adolescent↗
PubMed2000

Transcriptional regulation of the human FTZ-F1 gene encoding Ad4BP/SF-1.

Ad4BP, also known as SF-1, is a steroidogenic tissue-specific transcription factor that is also essential for adrenal and gonadal development. Two mechanisms for the transcriptional regulation of the mammalian FTZ-F1 gene encoding Ad4BP in adrenocortical cells have been proposed in the previous studies: the crucial role of a cis-element, an E box for the steroidogenic cell-specific expression of mouse and rat FTZ-F1 genes, and a possible autoregulatory mechanism of the rFTZ-F1 gene by Ad4BP itself through binding to the Ad4 (or SF-1) site in the first intron. In the present study, the transcriptional regulation of the human FTZ-F1 gene in adrenocortical cells was investigated from several angles, including the above two mechanisms. Using a series of deletion analyses of the 5'-flanking region of the hFTZ-F1 gene and site-directed mutagenesis for transient transfection studies, an E box element, CACGTG at -87/-82 from the transcriptional start site, was also found to be essential for the transcription of the hFTZ-F1 gene in mouse or human adrenocortical cell lines as well as in non-steroidogenic CV-1 cells. Despite the presence of a corresponding Ad4 site, CCAAGGCC at +163/+156 in the first intron of the hFTZ-F1 gene, an autoregulatory mechanism through the Ad4 site was found to be unlikely in the hFTZ-F1 gene mainly due to site-directed mutagenesis. In addition, the forced expression of Ad4BP had little effect on hFTZ-F1 gene transcription in non-steroidogenic CV-1 cells. Such Ad4BP-independent regulation of the hFTZ-F1 gene was in striking contrast to the regulation of steroidogenic CYP genes, such as the human CYP11A gene, in which the proximal promoter activity is Ad4BP-dependent and the transactivation by Ad4BP is silenced by DAX-1. Even though the Ad4BP-dependent transcriptional regulation of the DAX-1 gene has been reported, DAX-1 did not affect the transcriptional activity of the hFTZ-F1 gene in our study. Taken together, these observations suggest that the E box is indeed required for the expression of the FTZ-F1 gene, at least in mammalian species, but may not determine the tissue-specific expression of the hFTZ-F1 gene, and that, unlike the steroidogenic CYP gene, the regulation of the hFTZ-F1 gene appears to be independent of both Ad4BP and DAX-1.

Adrenal Cortex↗
PubMed2000

Inhibin-like immunoreactivity produced by the adrenal gland is circulating in vivo.

To clarify the contribution of the inhibin-like immunoreactivity (inhibin-LI) produced by adrenal glands to the total circulating levels of inhibin-LI, we measured serum inhibin-LI in normal and hypogonadal subjects under ACTH-loading or dexamethasone-loading condition. The mean basal concentration of inhibin-LI in the peripheral serum of the hypogonadal cases was 3.6 +/- 1.3 IU/ml (mean +/- SD, n = 5), which corresponded to 19.5 +/- 5.8% of that of normal controls matched for age and sex. The low levels of inhibin-LI in hypogonadal subjects (n = 7) rose significantly (3.6 +/- 1.1 vs 8.1 +/- 1.7 IU/ml, p < 0.001) after the administration of synthetic 1-24ACTH (40 units/day intramuscular injection) for 2 days, while the levels of serum inhibin-LI were not increased in two cases of Addison's disease with hypogonadism after the administration of ACTH. After the oral administration of a low dose of dexamethasone (1 mg) the serum inhibin-LI level in normal subjects (eight males and eight females) decreased significantly (male, 16.2 +/- 3.3 vs 14.5 +/- 4.1 IU/ml; female, 12.9 +/- 6.3 vs 10.8 +/- 5.6 IU/ml; p < 0.01 each) without significant change in the levels of serum gonadotropin (LH and FSH) and those of gonadal steroid (testosterone or estradiol). These results indicate that a small; but significant amount of inhibin-LI is secreted from the adrenal gland and circulating in vivo, and that the proportion of adrenal-derived inhibin-LI is much higher in patients with hypogonadism.

Adrenal Glands↗
PubMed1999

Novel germline mutations of the MEN1 gene in Japanese patients with multiple endocrine neoplasia type 1.

Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant disorder characterized by tumors of the parathyroid glands, the pancreatic islet cells, and the anterior pituitary. Germline mutations of the MEN1 gene in three independent Japanese cases with MEN1 were analyzed. Case 1 has revealed a 2-bp (TA) insertion at nucleotide position 341 (341insTA) in exon 2, which shifts the reading frame such that the mutant protein has a completely different amino acid sequence from codon 78 to the premature stop codon at 119. In case 2, a nucleotide substitution, i.e., TAG in place of TGG, which encodes tryptophan at codon 198 was identified (nonsense mutation). These mutations were heterozygously present and have not been reported previously. Case 3 showed no mutations in the protein-coding exons and exon-intron junctions of the MEN1 gene by single-strand conformation polymorphism or direct sequencing of the polymerase chain reaction (PCR) fragments. We confirmed the finding that patients with MEN1 carry heterozygous germline mutations in the MEN1 gene, which is compatible with the idea that the MEN1 gene is a tumor suppressor gene. The reason why mutations in the coding region of the MEN1 gene could not be detected by PCR-based analysis in some of the MEN1 patients, e.g. case 3, needs to be clarified further.

Adult↗
PubMed1999

Serosurvey of wild rodents for Rickettsioses (spotted fever, murine typhus and Q fever) in Java Island, Indonesia.

The prevalence of antibodies against spotted fever group rickettsia (SFGR), murine typhus and Q fever were investigated in wild rats captured in Indonesia. Sera of 327 rats were collected from Jakarta and Boyolali on Java Island. The prevalences of antibodies against SFGR and murine typhus were 128 (39.1%) and 48 (14.7%), respectively. Antibodies against Q fever were not detected in these serum samples. Antibodies against SFGR were found in all species of rats (20.8-51.9%). The antibody positive rate against murine typhus in Rattus norvegicus (38.0%) was significantly higher than that in other rat species (0-4.8%, p<0.01). The antibody positive rates against SFGR and murine typhus in rats captured in Jakarta were significantly higher than those in rats captured in Boyolali (p<0.01). In this survey, all species of rats had antibodies against SFGR, indicating that the 4 species of tested rats (R. norvegicus, R. rattus, R. exulans, R. tiomanicus) were infected with SFGR and that SFGR may infest the whole of Java Island. Most of the rats that were antibody-positive against murine typhus were captured in Jakarta. Therefore, R. norvegicus and R. rattus are likely to be important hosts of murine typhus in Jakarta. The antibody-positive rates against SFGR and murine typhus in rats captured in the dry season were significantly higher than those in rats captured in the rainy season. This may coincide with the active periods of ticks and fleas in Indonesia.

Animals↗
PubMed1999

Sleep stage and skin temperature regulation during night-sleep in winter.

To clarify the thermally comfortable environment for satisfied sleep, we investigated the relationship between skin temperatures and sleep stages during night-sleep in winter, summer and autumn. Four healthy young females served as the subjects. The experiments were performed in a climate chamber under three conditions: at 13 degrees C-RH70% with futon and blanket in winter, at 20-18 degrees C-RH60% with futon and towelket in autumn and at 29 degrees C-RH70% with towelket in summer. The subjects' skin temperature on the sole was lower until about 4 hours after lights off in winter than in autumn and summer, and the percentage of st.2 was lower and st.4 was higher in winter than in autumn and summer, although the bed climate both in winter and autumn was much the same.

Adult↗
PubMed1999

A reverse-sandwich enzyme-linked immunosorbent assay for verocytotoxin 1 and 2 antibodies in human and bovine sera.

A reverse-sandwich enzyme-linked immunosorbent assay (ELISA), in which an antibody is sandwiched by antigens, was established for the titration of antibodies to verocytotoxins (VT) in human and animal sera. This assay has two advantages over a conventional indirect ELISA: (i) higher specificity and sensitivity and (ii) the ability to comparably titrate antibodies from different species. The VT1 (Shiga-like toxin 1) antibody-positive rates were 5% in 202 normal adult humans and 99% in 93 normal cattle at a dairy farm. This ELISA is most suitable for seroepidemiologic studies of infections with VT-producing Escherichia coli in humans and various animal species.

Adolescent↗
PubMed1999

Thiazolidinedione induces apoptosis and monocytic differentiation in the promyelocytic leukemia cell line HL60.

Thiazolidinedione (TZD) is known to be a potent activator of peroxisome proliferator-activated receptor gamma (PPARgamma), a nuclear receptor that constitutes a heterodimer with retinoid X receptor (RXR). Since a considerable amount of PPARgamma is expressed in various hematopoietic cells, the present study was undertaken to examine the effect of TZD in the absence or presence of LG100268, an RXR-selective ligand, on a cultured promyelocytic leukemia cell line, HL60. Treatment with TZD (25-50 microM troglitazone or pioglitazone) markedly suppressed cell proliferation of HL60. A cell cycle analysis revealed that the suppressive effect of troglitazone on HL60 cell proliferations was caused by G0/G1 cell cycle arrest as well as by an apoptotic effect. Treatment with the same concentration of troglitazone also induced the monocytic differentiation of HL60 cells. The apoptotic or the differentiating effect of TZD on HL60 cells was synergistically enhanced by the combined treatment with 1 microM LG100268, while LG100268 alone neither had an apoptotic nor a differentiating effect on HL60 cells. These results suggest that these actions are mediated through the nuclear receptor system constituted by the PPARgamma: RXR heterodimer.

Antineoplastic Agents↗
PubMed1999

Dax-1 as one of the target genes of Ad4BP/SF-1.

The DAX-1 (also known as AHC) gene encodes an unusual member of the nuclear hormone receptor superfamily. DAX-1 plays a critical role during gonadal and adrenal differentiation since mutations of the human DAX-1 gene cause X-linked adrenal hypoplasia congenita associated with hypogonadotropic hypogonadism. In recent studies, DAX-1 was reported to function as a transcriptional suppressor of Ad4BP/SF-1, a critical transcription factor in gonadal and adrenal differentiation. With respect to implication of Ad4BP/SF-1 in the transcriptional regulation of the DAX-1 gene, inconsistent findings have been previously reported. We investigated the upstream region of the mouse Dax-1 (also known as Ahch) gene and identified a novel Ad4/SF-1 site by transient transfection and electrophoretic mobility shift assays. In addition, immunohistochemical analyses with a specific antibody to Dax-1 indicated the presence of immunoreactive cells in steroidogenic tissues, pituitary gland, and hypothalamus. Although the distributions of Dax-1 and Ad4BP/SF-1 were very similar, they were not completely identical. The expression of Dax-1 was significantly impaired in knock-out mice of the Ftz-f1 gene, which encodes Ad4BP/ SF-1. Taken together, our findings indicate that Ad4BP/SF-1 controls the transcription of the Dax-1 gene.

Adrenal Cortex Neoplasms↗
PubMed1999

Short report: prevalence of antibodies against spotted fever, murine typhus, and Q fever rickettsiae in humans living in Zambia.

The causative agents of rickettsial diseases (Rickettsia conorii, R. typhi, and Coxiella burnetii) have been reported throughout the African continent. However, there have been no reports on epidemiologic surveys of these infections in Zambia. This study was designed to clarify the prevalence of three rickettsioses in 377 humans in Zambia. The seroprevalence of antibodies against R. conorii, R. typhi, and C. burnetii was 16.7%, 5.0%, and 8.2%, respectively. The rates of antibody positivity against R. conorii and C. burnetii were higher in the eastern (23.1% and 11.8%) and western (16.8% and 7.4%) areas of Zambia than in the northern (3.0% and 3.0%) area of this country. There was little difference among the three areas in the distribution of antibodies against R. typhi. Since cattle breeding is more extensive in the western and eastern areas than in the northern area, it is thought that cattle-breeding areas are foci of R. conorii and C. burnetii infections in Zambia.

Adolescent↗
PubMed1999

A case of late onset cyclosporine-induced hemolytic uremic syndrome resulting in renal graft loss.

A case of late onset hemolytic uremic syndrome (HUS) associated with cyclosporine (CYA) is described in this report. A 50-yr-old man with end-stage renal failure due to immunoglobulin A (IgA) nephropathy received a renal transplant from his wife. Human leucocyte antigen was completely unmatched. Immunosuppressant was a combination of prednisolone, azathioprine, and CYA. He was discharged 1 month after transplantation, with no episode of acute rejection. Twenty-one months after transplantation, his platelet count and hematocrit began to decrease and lactate dehydrogenase began to increase. Graft biopsy showed thrombotic microangiopathy and recurrent IgA nephropathy. Graft function was rapidly deteriorated and methylprednisolone pulse therapy was not effective. Twenty-five months after transplantation, he returned to a regular hemodialysis. Hemolysis was immediately improved after a reduction of the dose of CYA to 50 mg/d. The trough level of CYA was less than 200 ng/mL in most periods of his clinical course. Blood pressure was high throughout the clinical course. Although acute vascular rejection or malignant hypertension could also cause a thrombotic microangiopathy, CYA was most likely a cause of HUS in the present case because of the following reasons: neither anti-acute rejection therapy nor an adequate control of his blood pressure was effective in improving clinical features of HUS; hemolysis and thrombocytopenia disappeared immediately after the reduction of the dose of CYA to 50 mg/d. It has been reported that HUS carried poor prognosis only when occurring shortly after transplantation in cadaver kidney recipients. The present transplant was from a living donor and HUS occurred 21 months after transplantation and was severe enough to result in graft loss. High blood pressure might be one of the predisposing factors of HUS associated with CYA in the present case. CYA should be stopped and other alternative immunosuppressants should be given in cases of acute graft deterioration with hemolysis and thrombocytopenia, irrespective of the interval from transplantation, CYA dose, or CYA trough level.

Cyclosporine↗
PubMed1998

Characterization of temperature rise of the brain and the rectum following intracerebroventricular administration of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate and kainate in rats.

Intracerebroventricular administration of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) or kainate caused a rise of the temperature of the brain and the rectum in urethane-anesthetized rats. An AMPA-kainate receptor antagonist, 6,7-dinitroquinoxaline-2,3-dione (DNQX), significantly suppressed the AMPA- and kainate-induced rises of brain and rectal temperatures. An N-methyl-d-aspartate receptor antagonist, MK-801, also suppressed the rises of the brain and rectal temperatures induced by AMPA or kainate, but the profiles of the suppressive effects of MK-801 were different between rats treated with AMPA and kainate. An antipyretic agent, indomethacin, completely suppressed the AMPA-induced rises of brain and rectal temperatures. Although indomethacin completely suppressed the kainate-induced rise of the rectal temperature as well, the brain temperature was still raised. These findings suggest that distinct mechanisms may be involved in the temperature rise of the brain and the rectum mediated through AMPA and kainate receptor stimulation.

Analgesics, Non-Narcotic↗