A retroperitoneal bronchogenic cyst treated with laparoscopic surgery.
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Biomedical subjects
Publications and source records attributed to R Takayanagi.
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In the research field of nuclear receptors, the studies on the protein factors which interact with the steroid hormone receptors and regulate the transcriptional activity, and on the alpha and beta isoforms of glucocorticoid receptor have been in great progress. The include "intermediary Factors" such as RIP140, TIF-1, for the AF-2 which contribute to ligand-dependent transactivation function of the receptors. ARA70 which specifically interacts with androgen receptor was also cloned recently. Informations obtained from steroid hormone receptor knockout-mice experiments can also be available for the estrogen, glucocorticoid, and progesterone receptors. Furthermore, there have been more than sixty orphan receptors identified in these eight years, including HNF, Ad4BP, DAX-1, and nur77/NGFIB, some of which are mutation target genes of human congenital diseases.
Severe virilization syndrome is seen in testosterone-producing ovarian or adrenal tumor while symptom in late-onset congenital adrenal hyperplasia (CAH) are usually mild hirsutism and amenorrhea. We determined the serum levels of 17 alpha-hydroxy pregnenolone (17P5) and 17 alpha-hydroxyprogesterone (17P4) 60 min after the intravenous injection of 250 micrograms of ACTH in 10 normal Japanese females with age ranging from 18 to 29 years old. In this test, 1 mg of dexamethasone had been administered orally at 11 p.m. on the previous day to suppress the effect of endogenous ACTH. The ratio of 17P5 to 17P4 was 10.0 +/- 3.6 (mean +/- SD). Five females with hirsutism of no ovarian origin showed normal responses to this rapid ACTH test, suggesting that the incidence of the late-onset CAH is not so high as reported previously.
To clarify the antiatherogenic mechanism of action of dehydroepiandrosterone (DHEA), we investigated the effects of DHEA on the accumulation of cholesteryl ester (CE) in cultured mouse macrophage J774-1 cells. The accumulation of CE in J774-1 cells in the presence of acetyl low density lipoprotein (AcLDL) and 10(-5) mol/l DHEA was significantly reduced to 30% of the control values for 24 h. The marked effect of DHEA was observed as early as 6 h and continued at least for 48 h. This reduction by DHEA was dose-dependent and occurred starting at a DHEA dose of 5 x 10(-7) mol/1 for 24 h. DHEA treatment did not induced any changes in the cell surface binding, cell-association, or degradation of AcLDL. In comparison, the DHEA analogues, 8354 and 8356, which are known to be much stronger inhibitors of glucose 6-phosphate dehydrogenase than DHEA, did not show as marked an effect as DHEA on the accumulation of CE during the first 6 h. However, after 24-48 h of incubation, both 8354 and 8356 caused a marked reduction in the accumulation of CE similar to that observed with DHEA. A quantitative analysis of the cellular cholesterol content revealed that DHEA caused a marked reduction in CE with a concomitant continuous increase in free cholesterol (FC), while the DHEA analogues caused a marked reduction in CE with no change in FC. DHEA demonstrated little inhibitory effect on 25-hydroxycholesterol-driven esterification. Moreover, 10(-5) mol/1 DHEA induced a CE reduction in the foam cells induced by AcLDL. The CE-reducing capacity was also observed in the DHEA analogues. This CE-reducing capacity disappeared, however, when acyl CoA:cholesterol acyltransferase inhibitor, 58-035, was also present. Based on these findings, it can be concluded that the inhibitory effect of DHEA on the CE storage in response to AcLDL can be explained, at least in part, by two mechanisms. First, a recently published mechanism, namely, the inhibitory action of DHEA on lysosomal cholesterol transport, correlates well with the inhibition against foam cell transformation by DHEA in the early phase (at 6 h) observed in our study. With regard to the second mechanism, the CE-reducing capacity of DHEA from CE-laden foam cells, which appears to be related to a decreased cholesteryl ester cycle, may contribute to the inhibitory effect on the CE storage in the late phase (at 24 h and 48 h). These phase-specific inhibitory mechanisms of DHEA on the CE-storage may therefore partly explain the antiatherogenic action of DHEA.
Ad4BP (or steroidogenic factor 1, SF-1) has been implicated to be an essential transcriptional factor for steroidogenesis as well as for the development of the reproductive axis. We elucidated the structure of the human Ad4BP gene. The gene is about 30 kb long and is split into 7 exons including a non-coding exon 1. The deduced amino acid sequence of the human Ad4BP consists of 461 amino acid residues and was highly homologous to those of other mammalian species.
Androgen insensitivity syndrome (AIS) is associated with a wide range of quantitative or qualitative defects in the androgen receptor (AR). In some patients with AIS, however, no defects are detectable in the ligand-binding properties of the AR. We have analyzed the ARs of two unrelated patients with this category (termed 'receptor-positive type') of AIS. Sequence analysis of these patients' AR gene revealed single amino acid substitutions (579Cys(TGC)-->Phe(TTC) and 582Phe(TTC)-->Tyr(TAC)) in exon B encoding the first zinc finger of the DNA-binding domain of the AR. These mutations have not been previously reported. Moreover, cotransfection assays and mobility shift assays revealed that these patients' mutant ARs had defective transcriptional activity of the target gene because of impaired DNA-binding ability to the androgen-responsive element. These findings strongly indicate that these mutations are responsible for the pathogenesis of AIS in these patients.
A patient developed infective endocarditis caused by Campylobacter fetus. He gave a history of recent dental extraction and allogeneic tooth transplantation. He was treated with various antibodies to which the organism was said to be sensitive, but it was not until the transplanted tooth was removed that he started to improve. The mode of infection was thought to be blood borne through the open tooth socket from the raw chicken that he ate regularly.
OBJECTIVES: A transcription factor Ad4BP/SF-1 is implicated in the differentiation of gonadotrophs in the pituitary gland, but it is not known whether human pituitary cells express this factor. The present study aimed to disclose (1) whether human pituitary adenomas express Ad4BP/SF-1, and (2) if this is the case, what kinds of adenoma express the factor. MATERIAL: Total RNA was extracted from 23 pituitary adenomas obtained by transsphenoidal surgery, and subjected to Northern blot analyses using cDNAs of bovine Ad4BP/SF-1, porcine FSH-beta, LH-beta and glycoprotein hormone-alpha (GPH-alpha) subunts as radiolabelled probes. These adenomas included 13 clinically non-functioning adenomas, 1 GH/PRL-producing adenoma, 6 GH-producing adenomas, 2 PRL-producing adenomas and 1 ACTH-producing adenoma. RESULTS: The expression of Ad4BP/SF-1 exactly coincided with the expression of FSH-beta. Thus 5 out of 13 clinically non-functioning adenomas expressed Ad4BP/SF-1 and only these 5 adenomas expressed FSH-beta. Interestingly, only one of the GH-producing adenomas also expressed Ad4BP/SF-1 as well as FSH-beta. GPH-alpha was expressed in 4 non-functioning adenomas and 2 hormonally functioning adenomas, but did not necessarily coincide with Ad4BP/SF-1 expression. None of the 23 adenomas we tested expressed LH-beta, probably because LH-beta-producing adenomas are rather rare. CONCLUSIONS: The expression of FSH-beta was parallel with Ad4BP/SF-1 expression, indicating that the expression of Ad4BP/SF-1 is restricted to cells derived from gonadotroph lineages in human pituitary adenomas.
Sex differentiation is determined by a cascade of events proceeding from chromosomal sex to the completion of sexual maturation at puberty. Many factors involved in this cascade have been identified. Here we focus on DAX-1, androgen receptor and cytochrome P450c17, and discuss their functions in sex differentiation. We analyzed the DAX-1 genes of two unrelated Japanese patients with congenital adrenal hypoplasia and hypogonadotropic hypogonadism using PCR amplification of genomic DNA and complete exonic sequencing, and established that congenital adrenal hypoplasia and hypogonadotropic hypogonadism result from not only inherited but also de novo mutation in the DAX-1 gene. Androgen insensitivity syndrome (AIS) is a good model to clarify the relationship between the structure and function of androgen receptor, the androgen receptor gene mutation and clinical phenotype. We analyzed 15 cases of AIS and demonstrate the structural and functional relationships of the androgen receptor. We have sequenced the CYP17 (P450c17) gene in DNA from several patients with 17 alpha-hydroxylase deficiency, reconstructed the mutations in a human P450c17 cDNA and expressed the mutant P450c17 in COSl cells to characterize the kinetic properties of 17 alpha-hydroxylase and 17,20-lyase activities. The molecular bases of cases clinically reported as 17 alpha-hydroxylase deficiency have turned out to be complete or partial combined deficiencies of 17 alpha-hydroxylase/17,20-lyase.
Not every postmenopausal woman with a low level of estrogen suffers from osteoporosis, and no correlation of bone density with serum estrogen level, but a significant correlation with adrenal androgens is often noted. Vitamin D3 has been reported to be osteoclastic in vitro, whereas the effectiveness of vitamin D3 for the treatment of osteoporosis is clinically relevant. To study the roles of these factors in the development of osteoporosis, we characterized aromatase activity converting androgens to estrogens in human osteoblasts, because postmenopausal women maintain considerable levels of adrenal androgens. Glucocorticoids at 10(-9)-10(-7) M transiently induced the expression and enzymatic activity of aromatase cytochrome P450 (P450AROM) in primary cultured osteoblasts, and the Km value for androstenedione (4.7 +/- 2.9 nM) was lower than that in adipose tissue and skin. Human osteoblasts showed a promoter specificity different from that found in other tissues. 1,25-Dihydroxyvitamin D3 [1,25-(OH)2D3] alone did not induce aromatase activity, but enhanced and maintained glucocorticoid-induced P450AROM gene expression. This synergistic effect was not observed by other sex steroids or retinoic acids. The enhancement of P450AROM activity by 1,25-(OH)2D3 varied from 0.94-fold (no enhancement) to 2.40-fold (maximal enhancement) among the individual human osteoblasts examined, but the magnitude of the enhancement was significantly correlated with the level of vitamin D receptor messenger RNA (P < 0.05). Cycloheximide did not abolish the synergistic effect of 1,25-(OH)2D3, suggesting that de novo protein synthesis is not required for the synergism with 1,25-(OH)2D3. These results suggest that bone tissue can synthesize estrogen from adrenal androgens by a unique aromatase activity depending on the level of vitamin D receptor expressed.
Congenital adrenal hypoplasia, an X-linked disorder, is characterized by primary adrenal insufficiency and frequent association with hypogonadotropic hypogonadism. The X-chromosome gene DAX-1 has been most recently identified and shown to be responsible for this disorder. We analyzed the DAX-1 genes of two unrelated Japanese patients with congenital adrenal hypoplasia and hypogonadotropic hypogonadism by using PCR amplification of genomic DNA and its complete exonic sequencing. In a family containing several affected individuals, the proband male patient had a stop codon (TGA) in place of tryptophan (TGG) at amino acid position 171. As expected, his mother was a heterozygous carrier for the mutation, whereas his father and unaffected brother did not carry this mutation. In another male patient with noncontributory family history, sequencing revealed a 1-bp (T) deletion at amino acid position 280, leading to a frame shift and, subsequently a premature stop codon at amino acid position 371. The presence of this mutation in the patients' genome was further confirmed by digestion of genomic PCR product with MspI created by this mutation. Family studies using MspI digestion of genomic PCR products revealed that neither parent of this individual carried the mutation. These results clearly indicate that congenital adrenal hypoplasia and hypogonadotropic hypogonadism result from not only inherited but also de novo mutation in the DAX-1 gene.
Interferon-gamma (IFN gamma) is known to suppress the expression of thyroid-specific genes, such as thyroglobulin, thyroid peroxidase, and the TSH receptor (TSHR). In the present study, we show that this reflects, in part, a transcriptional action mediated by thyroid transcription factor-1 (TTF-1). Thus, transfected into rat FRTL-5 cells, the activity of reporter plasmids, containing rat TSHR promoter ligated to a chloramphenicol acetyltransferase gene, was significantly suppressed in the presence of rat IFN gamma. A -199-bp promoter construct showed the greatest suppression by IFN gamma whereas a -177-bp construct, in which the TTF-1 binding site was deleted, showed less suppressibility. The suppressive effect was rat IFN gamma-specific, since human IFN alpha, -beta, and -gamma exhibited no significant effects. The effect was concentration-dependent from 3-50 U/ml. In FRT rat thyroid cells that do not express TTF-1, IFN gamma-induced suppression on the promoter activity was not observed. In addition, when the TTF-1 binding site was mutated so that TTF-1 can not bind, IFN gamma-induced suppression was significantly reduced. In gel mobility shift analyses, a protein-DNA complex formed by TTF-1 was reduced when the nuclear extract prepared from IFN gamma-treated FRTL-5 cells was used; however, expression of TTF-1 mRNA and TTF-1 protein, which were assessed by Northern blot analysis and Western blot analysis, respectively, were not affected by IFN gamma treatment of FRTL-5 cells. Instead, reduction of DNA-binding affinity of TTF-1 was evident when competition analysis was performed in gel mobility shift analysis. From these results, we conclude that IFN gamma suppresses TSHR promoter activity, in part, by reducing TTF-1 binding to its recognition site. We also raise the possibility that the suppressive effect of IFN gamma on promoter activity is mediated by additional element(s) and factor(s) downstream of the TTF-1 site.
A decreased concentration of dehydroepiandrosterone sulfate (DHEA-S) in patients with Alzheimer's disease (AD) has been reported but is still controversial. In the present study, serum concentrations of DHEA and DHEA-S were determined in 19 patients with AD, 21 patients with cerebrovascular dementia (CVD) and 45 age- and gender matched elderly control individuals from the Japanese community at large. Serum concentration of DHEA among controls, patients with AD and patients with CVD did not significantly differ from one another. However, patients with AD and patients with CVD were found to have lower concentration of serum DHEA-S and a lower DHEA-S/DHEA ration compared to normal control individuals. No significant difference was observed in the concentration of serum DHEA-S or the DHEA-S/DHEA ratio between patients with AD and those with CVD. These results suggest that reduced concentrations of serum DHEA-S may not be unique to AD, but instead reflect a common phenomenon in dementing diseases. However, since serum concentration of DHEA in these patients remained unchanged, the significance of DHEA in dementia remains unclear.
Sterol carrier protein 2 (SCP2) has been implicated in adrenal steroidogenesis by in vitro studies. In order to clarify the clinical significance of SCP2 in human steroidogenesis, we investigated the expression of SCP2 mRNA in various types of adrenocortical tissue and one testis and examined the correlation between the amounts of SCP2 and other values such as the free cholesterol content and the cholesterol side-chain cleavage (SCC) activity in the tissue mitochondria. The types of adrenocortical tissue examined included adrenocortical carcinomas (N = 3), adrenocortical adenomas from patients with Conn's syndrome (N = 3) and from patients with Cushing's syndrome (N = 3), non-functioning adrenocortical adenomas (N = 2) and normal adrenal glands (N = 2). Northern blot hybridization predominantly revealed a 1.8-kb SCP2 mRNA in all tissue specimens examined. The mRNA concentrations of SCP2 in two out of three adrenocortical carcinomas were relatively lower than those in other types of tissue. No other special tendency was observed regarding the mRNA expression levels in various tissue specimens. The mRNA concentrations of SCP2 correlated significantly with mitochondrial contents of free cholesterol (r = 0.67, p < 0.01), but was not correlated with the SCC activities in mitochondria measured by an in vitro enzyme assay. The mitochondrial SCC activities, however, were correlated significantly with the protein levels of mitochondrial P-450 scc determined by a Western blot analysis (r = 0.79, p < 0.01). The significant positive correlation between mRNA concentrations of SCP2 and the mitochondrial content of free cholesterol suggests that the central role of SCP2 in human steroidogenic tissues may be in part a translocation of cytoplasmic free cholesterol to the mitochondria, as demonstrated previously by in vitro studies.
A 56-year-old male patient with cyclic Cushing's disease remained in a state of remission for more than one year with a relatively low dose of bromocriptine (2.5-3.75 mg/day). It has been reported that bromocriptine treatment for cyclic Cushing's disease induces only a transient remission; in the most effective cases, a relatively high dose (40 mg/day) was necessary. In the hypercortisolemic state, plasma adrenocorticotropic hormone (ACTH) and serum cortisol were not suppressed by dexamethasone and did not respond to corticotropin-releasing factor (CRF). An antehypophysectomy was not effective, even though the resected tissue contained ACTH-positive microadenomas. The present observations thus indicate the effectiveness of bromocriptine for some patients with this rare disorder.
A human T lymphoid cell line, PEER, dies by apoptosis in the presence of PMA and calcium ionophore. A new gene, TINUR, was cloned from apoptotic PEER cells. The expression of the TINUR gene is induced within 1 h after the cross-linking of the T cell Ag receptor complex. TINUR belongs to the NGFI-B/nur77 family of the steroid receptor superfamily and is an orphan receptor. TINUR binds to the same DNA sequence as NGFI-B/nur77. We also propose that the NGFI-B/nur77 family can be classified into two subtypes.
A case of primary hypothyroidism accompanied by pituitary enlargement and pituitary dysfunction is documented. A 27-year-old woman was admitted to our hospital for further examination of pituitary enlargement. Endocrinological examination revealed that she had primary hypothyroidism. Her TSH level in serum was elevated to more than 300 microU/ml. She also had pituitary dysfunction such as hypersecretion of prolactin in response to TRH and paradoxical rise of GH to glucose load. Serum antibodies against the pituitary gland were negative. Magnetic resonance imaging (MRI) examination showed an enlarged pituitary gland extending to supraseller cistern, which was homogeneously enhanced after Gadolinium-DTPA treatment. Treatment with 50-100 micrograms of levothyroxine sodium normalized her thyroid function and secretion of GH and prolactin. In addition, periodic MRI examination demonstrated a gradual decrease in the size of the pituitary gland after the treatment. The above clinical course indicates that pituitary enlargement in this patient occurred as a result of primary hypothyroidism. The mechanism of the abnormal secretion of TSH, GH and prolactin secondary to primary hypothyroidism was discussed.