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H Nawata

Publications and source records attributed to H Nawata.

At least 73 records · Page 4Linked to original sources
PubMed2001

Establishment and characterization of a steroidogenic human granulosa-like tumor cell line, KGN, that expresses functional follicle-stimulating hormone receptor.

We established a steroidogenic human ovarian granulosa-like tumor cell line, designated KGN, from a patient with invasive ovarian granulosa cell carcinoma. KGN had a relatively long population doubling time of about 46.4 h and had an abnormal karyotype of 45,XX, 7q-, -22. A steroid analysis of the cultured medium by RIA performed 5 yr after the initiation of culture showed that KGN was able to secrete pregnenolone and progesterone, and both dramatically increased after stimulation with (Bu)(2)cAMP. However, little or no secretion of 17alpha-hydroxylated steroids, dehydroepiandrosterone, androstenedione, or estradiol was observed. The aromatase activity of KGN was relatively high and was further stimulated by (Bu)(2)cAMP or FSH. These findings showed a pattern similar to that of steroidogenesis in human granulosa cells, thus allowing analysis of naturally occurring steroidogenesis in human granulosa cells. Fas-mediated apoptosis of KGN was also observed, which mimicked the physiological regulation of apoptosis in normal human granulosa cells. Based on these findings, this cell line is considered to be a very useful model for understanding the regulation of steroidogenesis, cell growth, and apoptosis in human granulosa cells.

Apoptosis↗
PubMed2001

Saturated FFAs, palmitic acid and stearic acid, induce apoptosis in human granulosa cells.

Obesity is associated with insulin resistance and some reproductive abnormalities. Circulating FFAs are often elevated in obese subjects and are also closely linked to insulin resistance. In this study, we demonstrated that saturated FFAs, such as palmitic acid and stearic acid, markedly suppressed the granulosa cell survival in a time- and dose-dependent manner. Polyunsaturated FFA, arachidonic acid, had no effect on the cell survival, even at supraphysiological concentrations. The suppressive effect of saturated FFAs on cell survival was caused by apoptosis, as evidenced by DNA ladder formation and annexin V-EGFP/propidium iodide staining of the cells. The apoptotic effects of palmitic acid and stearic acid were unrelated to the increase of ceramide generation or nitric oxide production and were also completely blocked by Triacsin C, an inhibitor of acylcoenzyme A synthetase. In addition, acylcoenzyme A, pamitoylcoenzyme A, and stearylcoenzyme A markedly suppressed granulosa cell survival, whereas arachidonoylcoenzyme A had no such effect, and this finding was consistent with the effect of the respective FFA form. Surprisingly, arachidonic acid instead showed a protective effect on palmitic acid- and stearic acid-induced cell apoptosis. A Western blot analysis showed the apoptosis of the granulosa cells induced by palmitic acid to be accompanied by the down-regulation of an apoptosis inhibitor, Bcl-2, and the up-regulation of an apoptosis effector, Bax. These results indicate that saturated FFAs induce apoptosis in human granulosa cells caused by the metabolism of the respective acylcoenzyme A form, and the actual composition of circulating FFAs may thus play a critical role in the apoptotic events of human granulosa cells. These effects of FFAs on granulosa cell survival may be a possible mechanism for reproductive abnormalities, such as amenorrhea, which is frequently observed in obese women.

Acyl Coenzyme A↗
PubMed2001

Transit endoscopic ultrasound of colorectal cancer using a 12 MHz catheter probe.

The objective of this study was to examine the accuracy of a 12 MHz ultrasound catheter probe in the pre-operative staging of colorectal cancer by assessing the depth of tumour infiltration and involvement of pericolonic lymph nodes. 159 patients with colorectal cancer who underwent ultrasound examination with a 12 MHz catheter probe were studied prospectively. The results of this imaging procedure were compared with the histological findings of the resected specimens. The accuracy of the 12 MHz ultrasound catheter probe for depth of invasion (T category) was 85% (131/154) for all tumours, 87% (46/53) for pT1 tumours, 60% (9/15) for pT2 tumours, 89% (74/83) for pT3 tumours and 67% (2/3) for pT4 tumours. The accuracy for tumours of the rectum and colon was 81% and 89%, respectively. The accuracy of the probe for nodal staging (N category) was 67% (76/114) overall. The sensitivity was 70% (33/47), the specificity 64% (43/67), the positive predictive value 58% (33/57) and the negative predictive value 75% (43/57). Endoscopic ultrasound using a 12 MHz catheter probe accurately assessed tumour stage, although nodal staging remained suboptimal. This method may aid in the selection of treatment for patients with colorectal cancer.

Adult↗
PubMed2001

Aberrant BCR-ABL transcript with intronic insertion in a patient with philadelphia chromosome-positive chronic myeloid leukemia: implications for disease progression.

The BCR-ABL fusion gene is important for the leukemogenesis of chronic myeloid leukemia (CML). A relationship between types of BCR-ABL transcripts in CML and clinical features has been proposed. We present here a patient with CML who carried an aberrant BCR-ABL transcript with an intronic sequence insert. A 26-year-old woman was diagnosed as having Philadelphia chromosome (Ph) positive CML. Reverse transcription polymerase chain reaction detected an atypically large BCR-ABL mRNA transcript. Sequencing revealed a 589bp insertion consisting of a 5' portion of BCR intron b2 and a 3' portion of ABL intron 1b between BCR exon b2 and ABL exon a2. Although the typical b2a2 transcript was undetectable initially, it appeared after intensive chemotherapy. The aberrant transcript presumably arose as a result of a lack of splicing, and chemotherapy might modify the disease course by selecting the subpopulation of the CML clone expressing typical BCR-ABL mRNA dominantly.

Adult↗
PubMed2001

The selenoorganic compound ebselen suppresses liver injury induced by Propionibacterium acnes and lipopolysaccharide in rats.

Ebselen (2-phenyl-1,2-benzoisoselenazol-3[2H]-one) is a selenoorganic compound containing selenium that has various pharmacological effects, including anti-inflammatory and antioxidant activity. Kupffer cells, residual hepatic macrophages, play an important role in the development of liver injury by producing free radicals and cytokines. The aim of this study is to evaluate whether ebselen suppresses macrophage-associated liver injury in rats. In vivo, we examined the effects of ebselen on liver injury, induced by Propionibacterium acnes and lipopolysaccharide (P. acnes-LPS), in rats where hepatic macrophages are considered to be primarily involved in injury development. Ebselen administration reduced the incidence of death following hepatic failure by P. acnes-LPS (82% vs. 20%, p<0.05). Serum levels of alanine aminotransferase, at 5 h after LPS administration, were significantly lower in the ebselen-treated group than in the control group (202.4+/-100.3 IU/l vs. 558.4+/-146.4 IU/l, p<0.05). Histological evidence of injury, such as necrosis, hemorrhage, and degeneration, was also suppressed by ebselen. Further, to assess the mechanisms involved, we investigated the production of cytokines and superoxide anions produced by activated hepatic macrophages in vivo. Serum levels of TNF alpha, interleukin-18 (IL-18)/IFN gamma-inducing factor (IGIF), and interferon gamma (IFN gamma) at 1 h after LPS administration were significantly lower in the ebselen-treated group. Formazan depositions, which were generated by the perfusion of the liver with nitroblue tetrazolium, were also observed less frequently in the ebselen treated group, suggesting a suppression in the release of superoxide anion from activated hepatic macrophages. In addition, we examined the effects of ebselen on cytokine production and mRNA expression, in vitro, using rat primary Kupffer cell culture. Ebselen also inhibited TNF alpha production and mRNA expression in vitro. These data imply that ebselen suppresses liver injury by inhibiting the production and/or release of proinflammatory cytokines and superoxide from activated hepatic macrophages. These data also suggest that ebselen is potent in the prevention of hepatic injury, such as endotoxemia, where hepatic macrophage activation has been implicated.

Alanine Transaminase↗
PubMed2001

Dimethyl sulfoxide inhibits dimethylnitrosamine-induced hepatic fibrosis in rats.

We studied the preventive effects of dimethyl sulfoxide (DMSO) on experimental hepatic fibrosis induced by dimethylnitrosamine (DMN) in rats. Treatment with DMN caused a significant decrease in body and liver weight. Oral DMSO (2 ml/kg daily for 4 weeks) essentially prevented this DMN-induced body and liver weight loss with no major side effects. DMSO suppressed the induction of hepatic fibrosis, as determined by histological evaluation, and reduced hepatic hydroxyproline. It also suppressed the expression of mRNA for type I collagen in the liver. Because hepatic stellate cells (HSC) are the major cellular source of the collagen in hepatic fibrosis, we examined the effects of DMSO on collagen production in vitro using rat primary HSC culture. However, it was found that DMSO did not inhibit the collagen production in vitro. We next evaluated the effects of DMSO on tumor necrosis factor alpha (TNFalpha) and nitric oxide (NO) production by Kupffer cells, because these factors represent major activator of HSC, and because monocyte-macrophage infiltration has been implicated as being pathogenetically important for hepatic fibrosis induced by DMN. DMSO inhibited lipopolysaccharide (LPS)-induced TNFalpha and NO production, and reduced TNFalpha mRNA levels. DMSO also suppressed the LPS-induced nuclear factor kappa B activation in a murine macrophage-like cell line. These results suggest that the inhibitory effects of DMSO on hepatic fibrosis may be primarily exerted via blocking of DMN-induced inflammation. These results also implied that DMSO may be potentially useful for preventing the development of hepatic fibrosis.

Animals↗
PubMed2001

Aberrant intracellular localization of RCAS1 is associated with tumor progression of gastric cancer.

A novel tumor-associated antigen, RCAS1 (receptor-binding cancer antigen expressed on SiSo cells) is expressed at a high frequency in human uterine and ovarian cancer cells as well as in other mammalian cancer cells. We investigated a relationship between RCAS1 expression and clinicopathological features in gastric cancer. Immunohistochemically, RCAS1 was detected in 98.4% of gastric carcinomas. However, its expression was also observed in non-cancerous gastric epithelial cells including gastric adenomas (100%), gastric ulcers (66.7%) and normal gastric epithelia (100%). Striking difference was observed in the pattern of RCAS1 expression between benign and malignant cells. In cases of normal gastric mucosae, gastric ulcers and gastric adenomas, RCAS1 was localized only in the perinuclear region of the mucosal epithelial cells (PN pattern), while, in most of gastric cancers (83.9%), it was detected diffusely in the cytoplasm and cell membranes of the tumor cells (DC pattern). In semi-quantitative RT-PCR analysis, RCAS1 mRNA levels in gastric adenocarcinoma tissues were significantly higher than those in non-neoplastic tissues (p=0.038). The PN pattern of RCAS1 expression was more frequently observed in well differentiated adenocarcinoma (25%) than in moderately differentiated adenocarcinoma (0%) (p=0.01). In addition, it is noteworthy that DC pattern of RCAS1 expression was more frequently recognized in carcinomas which invaded beyond the submucosa (100%) compared to intramucosal carcinoma (67.7%) (p=0.0026). These findings suggest that altered intracellular distribution of RCAS1 is strictly associated with tumor progression of gastric cancer and is a useful marker for the diagnosis and prognosis in gastric cancer.

Adenocarcinoma↗
PubMed2001

[Two cases of B cell lymphoma associated with hemophagocytic syndrome].

B cell lymphoma-associated hemophagocytic syndrome (B-LAHS) is clinically characterized by hepatosplenomegaly and bone marrow invasion without lymphadenopathy and skin lesions. Several cases of B-LAHS have been reported to demonstrate histopathologic findings of intravascular lymphomatosis (IVL), which in Western countries is characterized by a high rate of skin involvement and, rarely, bone marrow involvement and hemophagocytosis. Here we describe two interesting cases of B-LAHS. One patient was a 52-year-old woman whose bone marrow showed proliferation of large CD20-positive cells and hemophagocytosis at presentation. Combination chemotherapy was not effective, and the patient died of progressive disease. At autopsy, the lymphoma cells showed extravascular proliferation in many organs such as the bone marrow and liver, whereas in the adrenal glands, the lymphoma cells showed intravascular proliferation. The other patient was a 50-year-old man who had swellings of the bilateral kidneys and adrenal glands at presentation. Skin involvement by large lymphoma cells, a rare complication of B-LAHS, was observed. At autopsy, there was no evidence of IVL. Both of these patients showed high fever and cytopenia, and the disease took an aggressive clinical course, as in other reported cases of B-LAHS.

Female↗
PubMed2001

[Protein S deficiency in three patients with thrombosis].

Protein S (PS) deficiency, which is caused by various factors including congenital and acquired disorders, is a risk factor for thrombophilia. We described 3 patients with different backgrounds, who all exhibited PS deficiency. The first patient was a 47-year-old woman who suffered from frequent cerebral infarctions, deep-vein thrombosis (DVT) of her lower extremities, and pulmonary thromboembolism. Her son suffered from skin necrosis due to PS deficiency and both had the same mutant allele of the PS gene. The second patient was a 50-year-old woman who experienced a cold sensation in her fingers. Her relatives had a history of cerebrovascular disease. No mutation was detected in her PS gene. The third patient was a 27-year-old man with antiphospholipid antibody. He suffered from thrombocytopenia, skin necrosis, DVT of his lower extremities, and pulmonary thromboembolism. A mutation was identified in the steroid hormone-binding globulin-like (SHBG) domain of his PS gene. Neither his parents nor siblings had a history of thrombosis. The mutations found in the first and third patients were both missense mutations in the SHBG domain that have not been reported previously. The third patient had a mutation in the site that is involved in binding to C4b-binding protein, which modifies the immune response. These three cases provide key insights into the pathophysiology of PS deficiency.

Adult↗
PubMed2000

Identification of novel first exons in Ad4BP/SF-1 (NR5A1) gene and their tissue- and species-specific usage.

It has been demonstrated that the mammalian Ad4BP/SF-1 (NR5A1) gene is regulated precisely in sex, tissue, and developmental stage specific manners. To clarify the complex transcriptional regulation, we investigated in the present study whether the gene transcription is regulated by multiple promoters accompanied by noncoding first exons. Novel first exons (Io and Ig) were identified downstream of the already identified exon Ia. Nucleotide sequences revealed that Ia and Ig exons were well conserved, whereas Io exon was less conserved among the mouse, rat, and human genes. Interestingly, the splice donor of the mouse and human Io and human Ig exons do not satisfy the consensus sequence. Transcripts containing Ia, Io, and Ig were detected in all rat tissues examined, while the transcript containing Io was undetectable in the corresponding tissues of mice. The lack of exon Io usage in the mouse was confirmed by transient transfection assays with cultured cells. Quantitative RT-PCR analysis revealed that the transcript containing Ig exon was the main product in the pituitary but significantly less in the spleen, suggesting that the regulation of Ad4BP/SF-1 gene transcription in the pituitary and spleen is distinct from that of other tissues. The above findings, together with the structural abnormality at the splice donor site, suggest that acquisition of the multiple first exons enables the Ad4BP/SF-1 gene to be regulated differentially in different animal species and in different tissues in the same animal.

Alternative Splicing↗
PubMed2000

A nuclear receptor system constituted by RAR and RXR induces aromatase activity in MCF-7 human breast cancer cells.

Estrogen is the most important endocrine hormone that stimulates the growth of hormone-dependent breast cancer. The biosynthesis of estrogens in breast tissue is catalyzed by cytochrome P450 aromatase (P450arom). The expression of P450arom is controlled by the tissue- or cell-specific promoters of CYP 19 gene. The roles of nuclear receptor systems for the aromatase activity in breast cancer cells have not yet been fully investigated. In the present study, we investigated the effects of a nuclear receptor system constituted by retinoid X receptor (RXR) and its heterodimer partner on the aromatase activity in a cultured MCF-7 human breast cancer cell line, using each selective ligand for retinoic acid receptor (RAR) (TTNPB), RXR (LG100268), PPARgamma (troglitazone), and vitamin D(3) receptor (vitamin D(3)). The treatment of the cells with TTNPB or LG100268 alone for 2 days increased slightly the aromatase activity, but the increases were not statistically significant in comparison to the control. However, the combined treatment with TTNPB (10(-7) M) and LG100268 (10(-7) M) caused a dramatic stimulation of the aromatase activity. The treatment with other ligands had little or no effect on the aromatase activity. The stimulation of the aromatase activity by TTNPB plus LG100268 was dose-dependent, and a maximum stimulation was observed at 10(-7) M in both compounds. In addition, the increase in the aromatase activity was accompanied by an increase in the P450arom mRNA levels determined by RT-PCR in MCF-7 cells. The increase in the P450arom transcript was also found to be related to the specific usage of promoter 1a of the CYP 19 gene based on the analysis using RT-PCR. This is the first demonstration that a nuclear receptor system constituted by a RAR:RXR heterodimer is involved in the regulation of aromatase activity in MCF-7 breast cancer cells.

Aromatase↗
PubMed2000

Interferon gamma delays apoptosis of mature erythroid progenitor cells in the absence of erythropoietin.

Based on the hypothesis that interferon gamma (IFN-gamma) may have stimulating effects on survival of hematopoietic progenitor cells, we examined the effect of IFN-gamma on apoptosis of mature erythroid colony-forming cells (ECFCs) derived from human peripheral blood obtained from normal, healthy volunteers. When the cells were cultured in the presence of IFN-gamma, even without erythropoietin (EPO), the viability of the cells was maintained for at least 36 hours. When apoptosis of ECFCs was assessed by flow cytometric analysis', using annexin V, IFN-gamma reduced the extent of apoptosis of the cells, as well as EPO. DNA fragmentation of ECFCs was also reduced by IFN-gamma. In cells cultured with IFN-gamma alone, expression of Bcl-x was detected but the level of expression decreased gradually during incubation for 36 hours, and the expression level was lower than incubation with EPO. Fas expression and activation of downstream caspases were assessed by flow cytometric analysis or fluorometric protease assay. IFN-gamma induced Fas expression of the cells without the activation of caspase8 or caspase3 during 16 hours of incubation, while deprivation of EPO induced expression of Fas and the activation of both caspase8 and caspase3. We propose that IFN-gamma produces a stimulating signal for the survival of mature erythroid progenitor cells by reducing apoptosis through a mechanism other than modulating Fas and one related to the expression of Bcl-x. (Blood. 2000;95:3742-3749)

Annexin A5↗
PubMed2000

Selenoorganic compound, ebselen, inhibits nitric oxide and tumor necrosis factor-alpha production by the modulation of jun-N-terminal kinase and the NF-kappab signaling pathway in rat Kupffer cells.

In response to the bacterial endotoxin, LPS, Kupffer cells are induced to express NO and TNF-alpha. These compounds are involved in hepatic inflammation/injury, especially that associated with endotoxic shock. In this study, we demonstrate that ebselen (2-phenyl-1,2-benzisoselenazol-3[2H]one), a selenoorganic compound, blocks LPS-induced NO and TNF-alpha production by cultured rat liver Kupffer cells. LPS can activate both the NF-kappaB signaling pathway and MAPK signal transduction pathways such as JNK and p38 MAPK. We find that ebselen inhibits LPS-induced NF-kappaB nuclear translocalization, and also suppresses the LPS-induced phosphorylation of JNK, but not the phosphorylation of p38 MAPK. This inhibition of signal transduction leads to a decrease in the transcription of TNF-alpha and the inducible isoform of NO. Furthermore, ebselen inhibits LPS-induced COX-2 expression, which is responsible for proinflammatory prostaglandin production, without affecting constitutive COX-1 expression. These data suggest the mechanism by which ebselen acts as an antiinflammatory agent, and also suggest that ebselen may be potent in preventing hepatic injury such as endotoxic shock, in which Kupffer cell activation has been implicated.

Animals↗
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

Thyrotropin-releasing hormone interacts with vasoactive intestinal peptide-specific receptor in guinea pig cecal circular smooth muscle cells.

The relationship between thyrotropin-releasing hormone (TRH) binding sites and vasoactive intestinal peptide (VIP) receptors in circular muscle cells obtained from the guinea pig cecum was investigated using antagonists of VIP receptors and a selective receptor protection method. Both VIP10-28, a VIP antagonist, and atrial natriuretic peptide1-11 (ANP1-11), a VIP-specific receptor antagonist, completely inhibited 10(-5) M TRH-induced relaxation in a concentration-dependent manner. The muscle cells where cholecystokinin octapeptide (CCK-8) and TRH binding sites were protected completely preserved the inhibitory responses to TRH and ANP (a VIP-specific receptor agonist), and partially the inhibitory response to VIP. Peptide histidine isoleucine (PHI: a VIP-preferring receptor agonist) had no inhibitory effect on these cells. The muscle cells where CCK-8 and ANP (VIP-specific) receptors were protected completely preserved the inhibitory responses to TRH and ANP and partially the inhibitory response to VIP. PHI had no inhibitory effect on these cells. The muscle cells where CCK-8 and VIP receptors (both VIP-specific and VIP-preferring receptors) were protected preserved completely the inhibitory responses to TRH, VIP, ANP, and PHI. The muscle cells where CCK-8 and PHI (VIP-preferring) receptors were protected completely preserved the inhibitory response to PHI and partially the inhibitory response to VIP. TRH and ANP had no inhibitory effect on these cells. This study first demonstrates that TRH interacts with VIP-specific receptor in guinea pig cecal circular smooth muscle cells.

Animals↗