Search PubMed⌕ Search

Biomedical subjects

S Fujii

Publications and source records attributed to S Fujii.

At least 145 records · Page 8Linked to original sources
PubMed2000

Responses of wild watermelon to drought stress: accumulation of an ArgE homologue and citrulline in leaves during water deficits.

Wild watermelon from the Botswana desert had an ability to survive under severe drought conditions by maintaining its water status (water content and water potential). In the analysis by two-dimensional electrophoresis of leaf proteins, seven spots were newly induced after watering stopped. One with the molecular mass of 40 kilodaltons of the spots was accumulated abundantly. The cDNA encoding for the protein was cloned based on its amino-terminal sequence and the amino acid sequence deduced from the determined nucleotide sequences of the cDNA exhibited homology to the enzymes belong to the ArgE/DapE/Acy1/Cpg2/YscS protein family (including acetylornithine deacetylase, carboxypeptidase and aminoacylase-1). This suggests that the protein is involved in the release of free amino acid by hydrolyzing a peptidic bond. As the drought stress progressed, citrulline became one of the major components in the total free amino acids. Eight days after withholding watering, although the lower leaves wilted significantly, the upper leaves still maintained their water status and the content of citrulline reached about 50% in the total free amino acids. The accumulation of citrulline during the drought stress in wild watermelon is an unique phenomenon in C3-plants. These results suggest that the drought tolerance of wild watermelon is related to (1) the maintenance of the water status and (2) a metabolic change to accumulate citrulline.

Amidohydrolases↗
PubMed2000

Characterization of ovarian carbonyl reductase gene expression during ovulation in the gonadotropin-primed immature Rat.

In this differential-display polymerase chain reaction-based study, four different primer sets generated cDNA fragments of ovarian carbonyl reductase genes that were uniquely expressed during the ovulatory process in eCG-primed immature rats. The temporal pattern of expression of this aldo-keto reductase gene was delineated by extracting ovarian RNA at 0, 2, 4, 8, 12, and 24 h after induction of ovulation via injection of the primed animals with hCG. The results showed that at least four homologous forms of this gene were transcribed during ovulation. Northern blot analyses indicated a 14-fold increase in ovarian mRNA for carbonyl reductase, with expression reaching a peak at 8 h after hCG treatment and then declining to negligible levels during the next 16 h. In situ hybridization revealed that most of the transcription was in the thecal connective tissue of the ovary and was absent from the granulosa layer of ovarian follicles. Treatment of the animals with ovulation-blocking doses of epostane (an inhibitor of progesterone synthesis) or indomethacin (an inhibitor of prostanoid synthesis) did not reduce the expression of ovarian carbonyl reductase. Nevertheless, the temporal pattern of expression of carbonyl reductase after the induction of ovulation suggests that this enzyme activity is at least indirectly associated with the ovulatory process.

Alcohol Oxidoreductases↗
PubMed2000

Ovarian expression of a disintegrin and metalloproteinase with thrombospondin motifs during ovulation in the gonadotropin-primed immature rat.

Mammalian ovulation is a dynamic process that requires degradation of the collagenous connective tissue in the thecal layers of a mature follicle. In this reverse transcription-polymerase chain reaction differential display study, gonadotropin-primed immature rats were used to detect ovarian expression of a relatively new type of disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS-1) that is known to cleave extracellular matrix in acutely inflamed tissues. Immature Wistar rats were primed with 10 IU eCG s. c., and the temporal pattern of expression of the ADAMTS-1 gene was delineated by extracting ovarian RNA at 0, 2, 4, 8, 12, and 24 h after induction of ovulation by injecting the primed animals with 10 IU hCG s.c. The differential display data, Northern analyses, and in situ hybridization micrographs all showed significant up-regulation of ADAMTS-1 gene expression by 8 h after hCG administration. The in situ data indicated that the ADAMTS-1 mRNA was in the granulosa layer of mature follicles. Expression reached a peak at 12 h and remained elevated at 24 h after hCG. ADAMTS-1 gene expression was impaired by the antiprogesterone agent epostane, but this inhibition could be overcome by exogenous progesterone. ADAMTS-1 expression was not affected when ovulation was blocked by treatment of the animals with the anti-eicosanoid agent indomethacin. In conclusion, the temporal pattern of expression of this gene, and its apparent regulation by progesterone, suggests that ADAMTS-1 has a significant role in the inflammatory events of the ovulatory process.

ADAM Proteins↗
PubMed2000

Viral mutation accelerated by nitric oxide production during infection in vivo.

Nitric oxide (NO), superoxide (O(2)(-)), and their reaction product peroxynitrite (ONOO(-)) are generated in excess during a host's response against viral infection, and contribute to viral pathogenesis by promoting oxidative stress and tissue injury. Here we demonstrate that NO and peroxynitrite greatly accelerates the mutation of Sendai virus (SeV), a nonsegmented negative-strand RNA virus, by using green fluorescent protein (GFP) inserted into and expressed by a recombinant SeV (GFP-SeV) as an indicator for mutation. GFP-SeV mutation frequencies were much higher in the wild-type mice than in those lacking inducible NO synthase, suggesting that mutation of the virus in vivo is NO dependent. High levels of NO and NO-mediated oxidative stress were induced by GFP-SeV infection in the lung of the wild-type mice, but not in the iNOS-deficient mice, as evidenced by electron spin resonance spectroscopy and immunohistochemical analysis for nitrotyrosine formation as well as histopathological examination. Furthermore, peroxynitrite, an NO-derived reactive nitrogen intermediate, enhanced viral mutation in vitro. These results indicate that the oxidative stress induced by NO produced during the natural course of viral infection increases mutation, expands the quasispecies spectrum, and facilitates evolution of RNA viruses.

Animals↗
PubMed2000

In vivo gene delivery to tumor cells by transferrin-streptavidin-DNA conjugate.

To target disseminated tumors in vivo, transgenes [beta-galactosidase gene, green fluorescence protein (GFP) gene, herpes simplex virus thymidine kinase (HSV-TK)] were conjugated to transferrin (Tf) by a biotin-streptavidin bridging, which is stoichiometrically controllable, and Tf receptor (Tf-R) affinity chromatography, which selects Tf conjugates with intact receptor bindings sites from reacting with the linker. Tf-beta-galactosidase plasmid conjugate thus constructed was specifically transfected to human erythroleukemia cells (K562) via Tf-R without the aid of any lysosomotropic agents. The transfection efficiency of the conjugate was superior to those of lipofection (1% staining) and retroviral vector (5%) and slightly lower than that of adenovirus (70%). The high level of expression with our conjugate was confirmed using other tumor cells (M7609, TMK-1) whereas in normal diploid cells (HEL), which express low levels of Tf-R, expression was negligible. When GFP gene conjugates were systemically administered through the tail vein to nude mice subcutaneously inoculated with tumor, expression of GFP mRNA was found almost exclusively in tumors and to a much lesser extent in muscles, whereas GFP revealed by fluorescence microscopy was detected only in the former. To exploit a therapeutic applicability of this method, suicide gene therapy using Tf-HSV-TK gene conjugate for massively metastasized k562 tumors in severe combined immune-deficient mice was conducted, and a marked prolongation of survival and significant reduction of tumor burden were confirmed. Thus, this method could also be used for gene therapy to disseminated tumors.

Animals↗
PubMed2000

Immunohistochemical detection of the Wilms' tumor gene (WT1) in epithelial ovarian tumors.

The Wilms' tumor gene WT1 plays multiple roles in the development of the genitourinary organs and Wilms' tumors. The aims of this study were to immunohistochemically evaluate WT1 expression in normal female genital tissues and in epithelial ovarian tumors and to look for correlations between WT1 expression and histologic subtypes and cell proliferation in epithelial ovarian tumors. In normal female genital organs, WT1 expression was recognized in ovarian surface epithelium, the lining of inclusion cysts, and tubal epithelium, but not in the cervical or endometrial epithelium. In epithelial ovarian tumors, serous tumors generally revealed a high WT1 expression. Among adenocarcinomas, serous carcinoma revealed a significantly higher WT1 expression than the other histologic subtypes. There were no significant correlations between the WT1 labeling index and the Ki-67 labeling index, and no significant difference in survival between those showing high and low WT1 expression among the malignant cases. These results suggest that WT1 expression may be related to cell differentiation, and that the histologic subtypes of epithelial ovarian carcinomas may differ considerably in their biological characteristics.

Adenocarcinoma↗
PubMed2000

Relationship of renal histological damage to glomerular hypertension in patients with immunoglobulin A nephropathy.

OBJECTIVE: Studies of experimental animals show glomerular hypertension to be important in the progression of glomerular disease. We evaluated this connection clinically by examining the relationship between glomerular hemodynamics and histological changes in patients with immunoglobulin (Ig)A nephropathy. METHODS: The subjects were 23 patients with IgA nephropathy. All patients underwent renal biopsies. Glomerular hemodynamics, in terms of glomerular capillary hydraulic pressure (PGC) and the whole-kidney ultrafiltration coefficient, were calculated from the renal clearance, plasma total protein concentration, and pressure-natriuresis relationship. The severity of glomerulosclerosis, tubulointerstitial damage and mesangial matrix expansion was evaluated semiquantitatively. RESULTS: PGC ranged from 33-69 mm Hg, and the mean arterial pressure (MAP) from 79-112 mm Hg. Their correlation was not significant (r= 0.29, P= 0.18). PGC was significantly correlated with the glomerulosclerosis score, and also with the score for tubulointerstitial damage (r= 0.65, P < 0.001 and rs = 0.59, P = 0.007, respectively), but not with the score for mesangial matrix expansion (r= 0.08, P= 0.72). MAP was significantly correlated only with the score for tubulointerstitial damage (rs = 0.63, P = 0.004). In multiple linear regression analysis of the histological changes and hemodynamics, the glomerulosclerosis score and the score for tubulointerstitial damage were correlated with PGC, but not with MAP. CONCLUSION: These clinical results support the speculation that glomerular hypertension is involved in the glomerulosclerosis and tubulointerstitial damage that occurs in IgA nephropathy.

Adult↗
PubMed2000

Changes in the serum levels of human chorionic gonadotropin and the pulsatility index of uterine arteries during conservative management of retained adherent placenta.

OBJECTIVE: Our purpose was to assess the natural course of retained adherent placenta at term. METHODS: Five cases of retained adherent placenta, clinically diagnosed as placenta accreta, were managed conservatively without methotrexate. To assess the biochemical and circulatory changes in the placentas, the serum levels of human chorionic gonadotropin (hCG) and the pulsatility index (PI) of the uterine arteries were examined. RESULTS: Serum hCG levels decreased spontaneously; the half-life of serum hCG was calculated to be 5.2 +/- 0.26 days (mean +/- SEM). The PI of the uterine arteries remained at the level of pregnant women at term, but became elevated within a few days after the removal of the placentas. All the placentas were successfully removed transvaginally within 6 weeks postpartum. CONCLUSIONS: The changes in serum hCG observed in this study indicated the spontaneous degeneration of the placenta. Such changes might be similar to those reported to occur during treatment with methotrexate. In contrast, the PI of the uterine arteries did not reflect degeneration of the placenta.

Adult↗
PubMed2000

A comparative analysis of cross sectional imaging techniques in minimal deviation adenocarcinoma of the uterine cervix.

A pre-operative diagnosis of minimal deviation adenocarcinoma of the cervix is often difficult. We assessed transvaginal sonography, computed tomography and magnetic resonance imaging in 16 women with histologically confirmed minimal deviation adenocarcinoma. Increased fluid accumulation was frequently observed within the endometrial cavity and/or vagina by all three techniques. A multicystic cervical lesion was occasionally detected by transvaginal sonography or by computed tomography. On T2-weighted magnetic resonance images, a noncystic fine villous or multicystic lesion was noted in most cases. Among the three imaging techniques used, T2-weighted magnetic resonance images showed the most detailed features and the best correlation with the histology.

Adenocarcinoma↗
PubMed2000

Nitric oxide enhances expression and shedding of tumor necrosis factor receptor I (p55) in endothelial cells.

The biological actions of tumor necrosis factor-alpha (TNF-alpha) are mediated by 2 distinct receptors, TNF-RI (p55) and TNF-RII (p75). The extracellular domains of both receptors are shed in soluble form (sTNF-RI and sTNF-RII). The soluble receptors are involved in regulating TNF-alpha activities and may have therapeutic potential as TNF-neutralizing agents. However, it remains unclear as to what kind of physiological molecule can regulate TNF receptors. Nitric oxide (NO) mediates a variety of biological and pathophysiological functions. We hypothesized that NO may modulate the expression and shedding of TNF-RI. An NO donor, diethylamine/NO complex (NOC 5), increased sTNF-RI in the supernatants of ECV304, a human umbilical vein cell line, in a dose-dependent manner. TNF-RI mRNA in these cells was upregulated by NOC 5. 8-Br-cGMP and peroxynitrate had no effect on sTNF-RI release. Genistein and herbimycin A, inhibitors of tyrosine kinase, inhibited sTNF-RI release. Herbimycin A inhibited the levels of TNF-RI mRNA enhanced by NOC 5, which downregulated the surface expression of TNF-RI, indicating that NO is also involved in the shedding process of TNF-RI. The shedding of TNF-RI was abolished by a synthetic inhibitor of matrix metalloproteinase, KB-R8301. In conclusion, NO enhanced the release of sTNF-RI from endothelial cells by a cGMP-independent mechanism. Dual pathways suggested for NO-induced sTNF-RI release include (1) enhanced expression of TNF-RI, at least partially, by a tyrosine kinase-dependent mechanism and (2) increased shedding of TNF-RI by a type of metalloproteinase.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed2000

Accelerated puberty and late-onset hypothalamic hypogonadism in female transgenic skinny mice overexpressing leptin.

Excess or loss of body fat can be associated with infertility, suggesting that adequate fat mass is essential for proper reproductive function. Leptin is an adipocyte-derived hormone that is involved in the regulation of food intake and energy expenditure, and its synthesis and secretion are markedly increased in obesity. Short-term administration of leptin accelerates the onset of puberty in normal mice and corrects the sterility of leptin-deficient ob/ob mice. These findings suggest a role for leptin as an endocrine signal between fat depots and the reproductive axis, but the effect of hyperleptinemia on the initiation and maintenance of reproductive function has not been elucidated. To address this issue, we examined the reproductive phenotypes of female transgenic skinny mice with elevated plasma leptin concentrations comparable to those in obese subjects. With no apparent adipose tissue, female transgenic skinny mice exhibit accelerated puberty and intact fertility at younger ages followed by successful delivery of healthy pups. However, at older ages, they develop hypothalamic hypogonadism characterized by prolonged menstrual cycles, atrophic ovary, reduced hypothalamic gonadotropin releasing hormone contents, and poor pituitary luteinizing hormone secretion. This study has demonstrated for the first time to our knowledge that accelerated puberty and late-onset hypothalamic hypogonadism are associated with chronic hyperleptinemia, thereby leading to a better understanding of the pathophysiological and therapeutic implication of leptin.

Adipose Tissue↗
PubMed2000

Expression of tumor necrosis factor-stimulated gene-6 in the rat ovary in response to an ovulatory dose of gonadotropin.

Current evidence supports the hypothesis that the biochemical events of mammalian ovulation are analogous to an acute inflammatory reaction. This study reveals that tumor necrosis factor-stimulated gene-6 (TSG-6), which encodes a member of the superfamily of hyaluronan-binding proteins that is specifically translated in inflammatory reactions, is expressed in ovarian follicles that have been induced to ovulate. Immature Wistar rats were primed with 10 IU equine CG s.c.; and 48 h later, the 12-h ovulatory process was initiated by 10 IU human CG (hCG), s.c.. Ovarian RNA was extracted at 0, 2, 4, 8, 12, and 24 h after the primed animals were injected with hCG. The RNA extracts were used for RT-PCR differential display of amplified complementary DNAs (cDNAs) that represented gene expression in the stimulated ovarian tissue. Northern analysis of one of the differentially amplified cDNAs confirmed that it was part of a gene that was substantially up-regulated at 4-8 h after the ovaries had been stimulated by hCG. Subcloning and sequence analysis revealed that the cDNA matched the gene for TSG-6. In situ hybridization indicated that the TSG-6 messenger RNA was primarily located in the cumulus mass and the antral granulosa cells of large ovarian follicles. In conclusion, the data show that expression of TSG-6 is an integral part of the cascade of inflammatory-like changes that occur in an ovulatory follicle in response to a trophic hormone that couples with luteinizing hormone/hCG receptors.

Androstenols↗
PubMed2000

Epoxide hydrolase affects estrogen production in the human ovary.

To investigate the mechanisms of ovarian cell differentiation, we raised a new monoclonal antibody, HCL-3, which reacted with human luteal cells. It also reacted with human and porcine hepatocytes. The immunoaffinity-purified HCL-3 antigen from human corpora lutea (CL) was shown to be a 46-kDa protein. The N-terminal 22 amino acids of the 46-kDa protein from porcine liver exhibited high homology (82%) to human microsomal epoxide hydrolase (mEH). The purified HCL-3 antigen from human CL or porcine liver showed EH enzyme activity, confirming that HCL-3 antigen is identical to mEH, which is reported to detoxify the toxic substrates in the liver. In human follicles, mEH was immunohistochemically detected on granulosa and theca interna cells. In the menstrual and pregnant CL, mEH was also expressed on large and small luteal cells. A competitive inhibitor of EH, 1,2-epoxy-3,3,3-trichloropropane, inhibited the conversion of estradiol from testosterone by granulosa cells cultured in vitro, indicating the involvement of mEH in ovarian estrogen production. Because anticonvulsant sodium valproate and its analogues were reported to inhibit EH enzyme activity, these findings provide a new insight into the etiology of endocrine disorders that are frequently observed among epileptic patients taking anticonvulsant drugs.

Adolescent↗
PubMed2000

Dependence of estrogenic activity on the shape of the 4-alkyl substituent in simple phenols.

The ability of certain chemicals to mimic the effects of natural steroid hormones and their potential to disrupt the delicate balance of the endocrine system in animals has attracted much interest in recent years. Alkylphenolic chemicals have been reported to be weakly estrogenic. Estrogen receptor (ER) binding is primarily the result of interaction of the receptor with both a phenolic residue, and a hydrophobic pharmacophore. We have prepared and screened various phenols having a bulky 4-alkyl group, which may interact hydrophobically with the receptor, for estrogenic activity by using a previously described reporter gene assay employing COS-1 cells transfected with rat ER alpha-expression plasmid and an appropriate reporter plasmid. Some of the tested compounds, such as 4-(1-adamantyl)phenol and 4-cycloalkylphenols, exhibited much more potent activity than the typical estrogenic alkylphenol, 4-tert-octylphenol.

Animals↗
PubMed2000

Coronary artery bypass grafting in patients with hypopituitarism.

Three patients with angina pectoris and hypopituitarism underwent coronary artery bypass grafting. The patients received perioperative replacement steroid and thyroid hormone therapy, and there were no complications. Careful perioperative hormonal management is necessary for patients with hypopituitarism.

Aged↗
PubMed2000

STS-95 space experiment for plant growth and development, and auxin polar transport.

The principal objective of the space experiment, BRIC-AUX on STS-95, was the integrated analysis of the growth and development of etiolated pea and maize seedlings in space, and the effect of microgravity conditions in space on auxin polar transport in the segments. Microgravity conditions in space strongly affected the growth and development of etiolated pea and maize seedlings. Etiolated pea and maize seedlings were leaned and curved during space flight, respectively. Finally the growth inhibition of these seedlings was also observed. Roots of some pea seedlings grew toward the aerial space of Plant Growth Chamber. Extensibilities of cell walls of the third internode of etiolated pea epicotyls and the top region of etiolated maize coleoptiles which were germinated and grown under microgravity conditions in space were significantly low. Activities of auxin polar transport in the second internode segments of etiolated pea seedlings and coleoptile segments of etiolated maize seedlings were significantly inhibited and extremely promoted, respectively, under microgravity conditions in space. These results strongly suggest that auxin polar transport as well as the growth and development of plants is controlled under gravity on the earth.

Biological Transport↗
PubMed2000

Role of interferon-alpha and clonally expanded T cells in the immunotherapy of chronic myelogenous leukemia.

Twenty five percent of patients in the chronic phase of chronic myelogenous leukemia (CML) are treated with interferon-alpha (IFN-alpha) to induce a cytogenic remission. In addition to its direct effects on leukemic cells, IFN-alpha has been shown to induce immunologic alterations, including upregulation of the expression of major histocompatibility (MHC) antigens in antigen-presenting cells (APCs), as well as augmentation of the activity of the lymphocytes against tumor cells. However, there has been little direct evidence supporting a causal interaction between cellular immunoreactivity and clinical responsiveness to IFN-alpha. We have shown that one approach to elucidate the immunological mechanisms by which IFN-alpha exerts its anti-CML activity is by analyzing therapy-induced modulation in T-cell receptor (TCR) Vbeta chain usage, using the reverse transcription-polymerase chain reaction (RT-PCR) followed by single-strand conformation (SSCP) analysis. This method is particularly attractive, since it provides an index of antigen-specific T cell expansion, but does not require the extraction and purification of the antigens involved in the T-cell response. T cell clones that express the Vbeta 10, 12, and 14 families predominate in the peripheral blood (PB) of CML patients. The enhanced expression of the Vbeta 9 and 20 families has been detected in IFN-alpha responsive patients but not patients who are poorly responsive to this agent. This suggests that expansion of T cells expressing these TCR Vbeta gene families may serve as a prognostic factors of the clinical responsiveness of CML patients to IFN-alpha. In addition, since T cell clones that express certain Vbeta families may react with a discrete set of antigenic peptides presented on the surface of malignant cells, a better understanding of the immunobiology of T cells in CML may allow for the design of increasing efficacious immune therapy for this disease.

Antigen Presentation↗