PubMed Health⌕ Search

Biomedical subjects

B Sato

Publications and source records attributed to B Sato.

At least 37 records · Page 2Linked to original sources
PubMed1997

Detection of herpes simplex DNA in semen and menstrual blood of individuals attending an infertility clinic.

OBJECTIVE: To determine a possible link between herpes simplex virus 1 (HSV) and infertility. METHOD: A specifically designed polymerase chain reaction with nested primers, was developed and used to test for HSV in 153 men and 20 women attending an infertility clinic. RESULTS: HSV DNA was detected in 37 (24%) out of 153 semen samples and in 11 (55%) out of 20 menstrual blood samples. However, HSV DNA (0%) was not detected in the semen of 16 males with children. A significant association between the evidence for infertility and an HSV positive test was observed in men (Fisher's exact test, p = 0.024), and a stronger effect was found in females after failed in vitro fertilization (Fisher's exact test p = 0.0086). CONCLUSION: This is the first report of the detection of herpes simplex virus DNA in semen and menstrual blood. Encouraging preliminary results justify antiviral therapy in case of a positive test.

Acyclovir↗
PubMed1997

Advanced glycation endproducts stimulate interleukin-6 production by human bone-derived cells.

Advanced glycation endproducts (AGEs), which result from nonenzymatic reactions of glucose with tissue proteins, have been shown to accumulate on long-lived proteins in advanced aging and diabetes mellitus. Thus, AGEs have been implicated in some of the chronic complications associated with these disorders. In this study, we investigated the effects of the glucose-modified protein on the production of the potent bone resorption factors by cells derived from explants of human bone. AGEs stimulated the release of interleukin-6 (IL-6) in the culture supernatants from the bone-derived cells and increased the levels of IL-6 mRNA in the cells. By contrast, the levels of IL-11 in the culture supernatants were not altered by AGEs, and the other bone resorption factors IL-1 alpha and IL-1 beta were undetectable (< 1.0 pg/ml) either without or with the treatment of AGEs. Electrophoretic mobility-shift assays revealed that the transcription nuclear factor-kappa B, which is critical for the inducible expression of IL-6, was activated in the nuclear extracts from mouse osteoblastic MC3T3-E1 cells treated with AGEs. These results suggest that AGEs are involved in bone remodeling modulation by stimulating IL-6 production in human bone-derived cells.

Alkaline Phosphatase↗
PubMed1996

Functional and possible physical association of scavenger receptor with cytoplasmic tyrosine kinase Lyn in monocytic THP-1-derived macrophages.

Acetyl LDL (modified low-density lipoprotein), which is thought to be taken up through scavenger receptor A (SR-A), rapidly induced the appearance of phosphotyrosine proteins in monocytic THP-1-derived macrophages in vitro. The two alternative forms of Lyn (p53 and p56) were found to be tyrosine-phosphorylated within 30 s after the stimulation with acetyl LDL. The catalytic activity of Lyn measured by an in vitro kinase assay had also increased in acetyl LDL-stimulated THP-1-derived macrophages. Furthermore, Lyn could be co-immunoprecipitated with SR-A from the cell lysate. These observations suggest a functional and possible physical association of SR-A with Lyn in THP-1-derived macrophages, and also imply a possible involvement of Lyn in SR-A signal transduction.

Amino Acid Sequence↗
PubMed1996

Fusigenic liposome-mediated DNA transfer into cardiac myocytes.

Current methods of gene transfer into cultured cardiac myocytes have serious limitations, including low efficiency, toxicity or constraints on DNA insert size. The present study examined the effectiveness of hemagglutinating virus of Japan (HVJ) in promoting liposome-mediated DNA transfer into cultured neonatal rat cardiac myocytes. Fluorescein isothiocyanate-labeled oligonucleotides (F-ODN) or plasmid expression vectors encoding SV40 large T antigen (pActSVT) and beta-galactosidase (pAct beta-gal) were complexed with liposomes and the viral protein coat of HVJ. Plasmid vectors were complexed with the nuclear localizing protein HMG-1 prior to HVJ-liposome encapsulation. Neonatal myocytes were transfected by incubation with HVJ-liposome/DNA complexes on culture day 3 or 7. Using F-ODN, we were able to demonstrate significant uptake of DNA (transfection efficiencies of 80-90%) 1 h after transfection that persisted for 1 week in culture. Interestingly, F-ODN were concentrated in the myocyte nuclei for the first 4 days after transfection. Immunohistochemistry showed that 25-30% of myocytes transfected with either pActSVT or pAct beta-Gal expressed plasmid-encoded protein at 72 h whether they were transfected at day 3 or day 7 of culture, while cells transfected with blank vectors did not. Quantitative beta-galactosidase assays confirmed that the use of HVJ significantly enhanced liposome-mediated transfection. Cell toxicity was not apparent. Gene transfer via intracoronary injection also demonstrated the capacity of HVJ to mediate transfection of rabbit cardiac myocytes in vivo, with F-ODN-dependent fluorescence persisting for up to 1 week. We conclude that HVJ/liposome-mediated transfer is efficient for the transfection of both oligonucleotides and plasmids into cardiac myocytes both in vitro and in vivo, and may provide a new tool for the investigation of cardiac myocyte biology and disease.

Animals↗
PubMed1996

Inhibition of growth and metastasis of ovarian carcinoma by administering a drug capable of interfering with vascular endothelial growth factor activity.

The present study investigates the relationship between in vivo growth/metastasis of tumor cells and their capacity to produce the vascular endothelial growth factor (VEGF), as well as the regulation of tumor growth/metastasis using an angiogenesis-inhibitory drug. Two cloned tumor cell lines designated OV-LM and OV-HM were isolated from a murine ovarian carcinoma OV2944. OV-LM and OV-HM cells grew in cultures at comparable rates. However, when transplanted s.c. into syngeneic mice, OV-HM exhibited a faster growth rate and a much higher incidence of metastasis to lymph nodes and lung. Histologically, intense neovascularization was detected in sections of OV-HM but not of OV-LM tumor. OV-HM and OV-LM tumor cells obtained from in vitro cultures expressed high and low levels of VEGF mRNA, respectively. A difference in VEGF mRNA expression was much more clearly observed between RNAs prepared from fresh OV-HM and OV-LM tumor masses: RNA from OV-HM contained larger amounts of VEGF mRNA, whereas RNA from OV-LM exhibited only marginal levels of VEGF mRNA. An angiogenesis-inhibitory drug, FR118487 inhibited the VEGF-mediated in vitro growth of endothelial cells but did not affect the expression in vitro of VEGF mRNA by OV-HM tumor cells. Intraperitoneal injections of FR118487 into mice bearing OV-HM tumors resulted in: (i) a subsequent growth inhibition of primary tumors; (ii) a marked decrease in neovascularization inside tumor masses expressing comparable levels of VEGF mRNA to those detected in control OV-HM masses; and (iii) almost complete inhibition of metastasis to lymph nodes and lung. These results indicate that growth/metastasis of tumor cells correlates with their VEGF-producing capacity and that an angiogenesis inhibitor, FR118487, inhibits tumor growth and metastasis through mechanism(s) including the suppression of VEGF function in vivo.

Animals↗
PubMed1996

New antitumor substances, FR901463, FR901464 and FR901465. I. Taxonomy, fermentation, isolation, physico-chemical properties and biological activities.

New antitumor substances, FR901463, FR901464 and FR901465 were isolated from the culture broth of a bacterium of Pseudomonas sp. No.2663. FR901463, FR901464 and FR901465 remarkably enhanced the transcriptional activity of the promoter of SV40 DNA virus. Further, these compounds exhibited potent antitumor activities against murine and human tumor cell lines in vitro.

Animals↗
PubMed1995

Quantitative analysis of redox gradient within the rat liver acini by fluorescence images: effects of glucagon perfusion.

The redox gradient along the sinusoid in the rat liver was studied using a redox scanner, a device based on tissue fluorescence scanning spectroscopy measuring the fluorescence signals of oxidized flavoprotein (FP) and reduced pyridine nucleotide (PN). The FP/(FP+PN) ratio reflects the mitochondrial redox state in the liver tissue. The distribution of mitochondrial redox state on the scanned area is expressed as two-dimensional gray-scale images with a 20 micron resolution. Using this instrument, we have scanned a 2.5 x 2.5 mm area of the frozen rat liver sample to investigate the redox gradient within acini and the effects of glucagon on the changes in the redox distribution. The redox images obtained in the perfused livers showed mosaic patterns implicating a regular heterogeneity of redox state in an acinus. The analysis of gradient curve, furthermore, clarified that the redox level in an acinus decreased sigmoidally from the periportal to the pericentral region. Glucagon, which has been reported to reduce the intracellular redox state, decreased the redox potential in whole acini, especially, in the periportal region, when compared with the perfusion without glucagon. These results strongly indicate an intraacinus heterogeneity of glucagon function, with glucagon selectively operating in the upstream of the sinusoid.

Animals↗
PubMed1995

Ligand-independent activation of tyrosine kinase in fibroblast growth factor receptor 1 by fusion with beta-galactosidase.

To examine the biological role of fibroblast growth factor receptor 1 (FGFR1) oligomerization for its signal transduction, we construct an expression vector encoding a FGFR1-beta-galactosidase fusion protein. This vector is designed to fuse the 3'-portion of FGFR1 to beta-galactosidase. Transfection of this vector into FGFR-negative rat L6 myoblast cells results in ligand-independent inhibition of differentiation into myocytes, suggesting that FGFR1 within this fusion protein is constitutively activated. This can be confirmed by demonstrating that this fusion protein exhibits the tyrosine kinase activity and phospholipase C gamma 1 is tyrosine-phosphorylated even in the absence of ligand stimuli. Since the transfected cells also exhibit the enzyme activity of beta-galactosidase which is known to be active only in a tetramer form, this constitutive activation can be elicited by tetramerization of FGFR1. Furthermore, deletion of a region corresponding to C terminal 10 amino acids important for tetramerization of beta-galactosidase from this expression vector abolishes the constitutively active nature of FGFR1 with simultaneous loss of beta-galactosidase activity. Transfection of non-deleted expression vector into NIH3T3 cells results in acquisition of focus-forming activity while a deleted form of expression vector fails to show this activity even in the presence of basic FGF. These results would suggest that tetramerization of FGFR1 can produce a constitutively active form responsible for transformation of NIH3T3 cells.

3T3 Cells↗
PubMed1995

Primary and reversible injury of H(+)-ATPase in warm ischemia and reperfusion of rat liver in relation to intramitochondrial adenine nucleotide.

The injury and recovery processes of complex reactions of liver mitochondrial ATP synthesis during warm ischemia and after reflow were studied separately in terms of the changes in oxidation (electron transfer system) and phosphorylation (H(+)-ATPase). Oxidative activity decreased significantly from the control value of 40 +/- 0.9 (mean +/- SEM, n = 5) to 31.5 +/- 1.13 (nanoatoms oxygen consumed/min/mg protein) after 40 min of warm ischemia, while phosphorylative activity decreased significantly from the control value of 1.06 +/- 0.12 to 0.42 +/- 0.03 (mumole ATP hydrolyzed/min/mg protein) after 20 min of warm ischemia. During 120 min of reflow after 20 min of warm ischemia, the decreased phosphorylation activity recovered to 0.52 +/- 0.01 concomitant with a recovery of intramitochondrial total adenine nucleotide and an increase in the ATP/ADP ratio, while oxidative activity decreased further to 23.9 +/- 0.81. These results indicate that H(+)-ATPase is more vulnerable to warm ischemia than the electron transfer system, but that it is restored concomitant with the recovery of intramitochondrial adenine nucleotide content.

Adenosine Diphosphate↗
PubMed1995

Intraoperative measurement of the graft oxygenation state in living related liver transplantation by near infrared spectroscopy.

Graft oxygenation plays an important role in successful liver transplantation. Intraoperative changes in the oxygenation state of the liver graft were measured by near infrared spectroscopy in 28 cases of living related liver transplantation. Oxygen saturation of hemoglobin in the liver (hepatic SO2) changed from 81.2% +/- 1.5% (mean +/- SEM) before donation (in the donor) to 49.7% +/- 4.2% after portal reflow, to 58.4% +/- 5.0% after arterial reflow, and then to 71.4% +/- 3.9% before closure. Mean hepatic SO2 was positively correlated with portal flow rate as measured by duplex Doppler sonography. Cases with low portal flow rate showed a high coefficient of variation (SD/mean) of hepatic SO2, indicating heterogeneous tissue oxygenation. Though graft size was expected to affect the graft oxygenation state, hepatic SO2 was fairly independent of the graft-to-recipient weight ratio. In two cases with markedly low hepatic SO2, postoperative graft dysfunction occurred. This study suggest that the method of near infrared spectroscopy is reliable and useful for assessing the graft oxygenation state in liver transplantation.

Adolescent↗
PubMed1995

Cold preservation-induced changes in oxygen radical generation between parenchymal and nonparenchymal cells in rat liver.

Many of the reports implicating the contribution of oxygen radicals to preservation-reperfusion injury have been based largely on indirect experiments demonstrating the effects or the consumption of various antioxidants. Investigations based on the direct measurement of the amounts of oxygen radicals that are actually formed during reoxygenation after preservation have not given satisfactory results. In this study, we attempted direct measurement of H2O2 from hepatocellular mitochondria and superoxide (O2-) from Kupffer cells, using the HRP method and cytochrome c perfusion method, respectively, for quantitative comparison of the cold preservation-induced changes in radical generation activity between these sources. H2O2 generation in mitochondria isolated after 24 h cold preservation decreased to 8% of non-preserved liver, but in the mitochondria isolated from the livers that were reperfused for 30 min after 24 h preservation H2O2 generation recovered to 60%. The respiratory control ratio also decreased significantly after 24 h preservation, and similarly recovered after an additional 30 min reperfusion. By contrast, O2- from Kupffer cells increased in time-dependent fashion until 12 h preservation and decreased after 24 h preservation. Although 12 h preservation did not cause an increase in LDH release, the lipid peroxide in the perfusate significantly increased after 12 h preservation, which indicated the occurrence of lipid peroxidation in the sinusoidal area. These results suggested that mitochondrial H2O2 was dependent upon the activity of respiratory function and so did not cause hepatocellular injury and that O2- from Kupffer cells contributed to oxidative injury to the sinusoidal lining cells. Our data support reports demonstrating the vulnerability of nonparenchymal cells.

Animals↗
PubMed1995

Molecular mechanism of androgen-dependent growth in transformed cells. Pathway from basic science to clinical application.

Shionogi carcinoma 115 (SC 115) has been extensively used to analyze the mechanism of androgen-dependent cancer growth. This tumor exhibits marked androgen-dependent growth in vivo and one cell line whose growth is markedly stimulated by androgen in serum-free culture condition is isolated from SC 115 tumor. This androgen-dependent growth is mediated through an induction of heparin binding growth factor termed as androgen-induced growth factor (AIGF). In addition, fibroblast growth factor receptor 1 (FGFR 1) is identified as a receptor for AIGF. The expression of FGFR 1 mRNA is up-regulated by androgen in SC 115 cells, indicating that this androgen-inducible autocrine loop is potentiated at two sites by androgen. An androgen-independent cell line is also established from this androgen-dependent SC 115 tumor. The growth of these androgen-independent cells is stimulated by AIGF, indicating that AIGF acts not only as an autocrine growth factor to androgen-dependent cells but also as a paracrine growth factor to androgen-independent cells. In addition, transfection of AIGF expression vector into androgen-dependent cells results in a facilitation of conversion from androgen-dependent to -independent phenotype. Thus, AIGF might play a role from tumor progression. These results indicate that a blockade of AIGF activity is an important therapeutic target. Actually, some compounds such as heparin and suramin are found to inhibit this androgen-induced autocrine loop. These basic observations will be discussed in relation to their possible clinical application.

Amino Acid Sequence↗
PubMed1995

Evaluation of water molecules in the cold-preserved rat liver by proton magnetic resonance imaging.

Hypothermically preserved rat livers were studied with proton magnetic resonance imaging (1H-MRI) under proton density-, spin-lattice relaxation time-, spin-spin relaxation time- and diffusion-weighted (P-W, T1-W, T2-W and D-W) conditions. Relative signal intensities (RSI) of the liver to distilled water in terms of P-W, T1-W, T2-W and D-W increased time-dependently during 12 h hypothermic (4 degrees C) preservation with saline, while these parameters did not increase during preservation with University of Wisconsin (UW) solution. One-hour Wiggers' hypotensive treatment before the harvesting increased the RSIs of P-W, T2-W and D-W, and the subsequent 12-hour preservation with UW solution did not improve the increased RSIs. These results suggest that 1H-MRI has potential application in evaluating the biophysical changes of water molecules in the liver graft, which were measured by placing the harvested liver in a plastic bag under a magnetic field at a low temperature.

Adenosine↗
PubMed1995

Identification of alternatively spliced messenger ribonucleic acid encoding truncated growth hormone-releasing hormone receptor in human pituitary adenomas.

The expression of GHRH receptor (GHRH-R) messenger ribonucleic acid (mRNA) was studied in 22 pituitary adenomas and 2 normal anterior pituitaries. Northern blot analysis revealed that GHRH-R mRNA were expressed in all 14 GH-producing adenomas, 1 of 3 ACTH-producing adenomas, the 1 PRL-producing adenoma, 2 of 4 nonfunctioning adenomas, and the 2 normal anterior pituitaries. Their expression levels varied among GH-producing adenomas and were relatively low in GH-nonproducing adenomas. In addition to the major transcript with a molecular mass of 2.0 kilobases (kb), the transcripts were identified at 2.8 and 4.5 kb in some GH-producing adenomas. To examine the structural variations in GHRH-R mRNA in pituitary adenomas, we amplified the complementary DNA fragment encompassing the region from the third cytoplasmic loop to the sixth transmembrane domain of GHRH-R. This region was selected because this region of the G protein-coupled receptor has been known to interact with G protein. Two amplified fragments with the molecular masses of 250 and 810 base pairs were identified by the reverse transcriptase-polymerase chain reaction method. The nucleotide sequence of a smaller fragment, which was the expected size, revealed that no mutations were found in this region in 10 GH-producing adenomas examined. However, a larger fragment contained the currently unidentified insertion. Compared with the genomic DNA sequence, this insertion was found to be generated through alternative splicing. In addition, this variant form contained the premature stop codon in-frame, indicating that it encodes the truncated GHRH-R. This insertion-specific probe could hybridize with 2.8- and 4.5-kb species of GHRH-R mRNA on Northern blot analysis, and these transcripts were expressed mainly in GH-producing adenomas. Finally, study of cell transfection and cAMP measurement revealed that this truncated GHRH-R was unable to transmit GHRH signals. These results suggest that some GH-producing adenomas preferentially express the truncated GHRH-R as a nonfunctioning receptor through alternative splicing.

Adenoma↗
PubMed1994

Changes in the distribution of the control of the mitochondrial oxidative phosphorylation in regenerating rabbit liver.

Applying the metabolic control theory, inhibitor titration studies were carried out on Complex I, III, IV, ATP synthase, ATP/ADP carrier and P(i) carrier of mitochondrial oxidative phosphorylation in normal and regenerating rabbit liver in order to examine the acceleration mechanism of mitochondrial oxidative phosphorylation. In regenerating rabbit liver the rate of state 3 respiration, respiratory control ratio and phosphorylation rate in the presence of mM glutamate, 250 microM ADP and 3 mM inorganic phosphate increased significantly as compared with the control by 73%, 48% and 76%, respectively. The control of the rate of state 3 respiration in normal liver was exerted by Complexes I, IV and steps other than the aforementioned six steps, whose flux control coefficients were 0.317, 0.214 and 0.469, respectively. By contrast, in regenerating liver, the control was more evenly distributed among these steps in oxidative phosphorylation and the possibility is suggested that Complexes I, IV and steps other than the six steps are activated during regeneration. The activation of Complexes I and IV was attributed to their increased activity, since it was not accompanied by an increase in the amount of the enzymes.

Adenosine Diphosphate↗
PubMed1994

Murine fibroblast growth factor receptor 1 gene generates multiple messenger RNAs containing two open reading frames via alternative splicing.

The arrangement of exons and introns encoding 5'-side of murine fibroblast growth factor (FGF) receptor 1 (FGFR-1) gene was mapped. A large intron with a size of 14 kb was identified between exon 1 and exon 2. In addition, all FGFR-1 subtypes including a unique variant form with 12 amino acids insertion and two amino acids deletion were observed to be able to be generated through alternative splicing. Furthermore, complete sequencing of the 5'-region of FGFR-1 mRNA revealed that a relatively large open reading frame precedes the major open reading frame encoding FGFR-1. These results indicate that FGFR-1 mRNAs are uniquely translated from an internal translation start site.

3T3 Cells↗
PubMed1994

Unsaturated fatty acids are required for continuous proliferation of transformed androgen-dependent cells by fibroblast growth factor family proteins.

Increase in dietary fat intake has been reported to be associated with progression of hormone-dependent cancers. To explore its mechanism, we examined the effects of fatty acids on the growth of androgen-dependent SC-3 cells cloned from mouse mammary cancer (Shionogi carcinoma 115). Their androgen-dependent growth was potentiated by linoleic acid in the defined medium. The effect of linoleic acid on fibroblast growth factor (FGF)-dependent growth was also addressed because androgen had been demonstrated to exert its mitogenic activity on SC-3 cells through an induction of the unique FGF family protein termed as androgen-induced growth factor. Exposure of SC-3 cells to basic FGF or androgen-induced growth factor exhibited only transient growth response. However, simultaneous addition of linoleic acid to the medium sustained the proliferation of FGF-stimulated, but not FGF-unstimulated, cells, although linoleic acid did not exert the significant effect on the process of S-phase entry of basic FGF-stimulated cells. Palmitoleic acid and oleic acid appeared to exert the actions similar to linoleic acid, while stearic acid was without any effect. Neither cyclooxygenase inhibitor nor 5-lipoxygenase inhibitor could block the growth-promoting ability of linoleic acid. Linoleic acid also enhanced their anchorage-independent growth in the presence of basic FGF. These results indicate that these unsaturated fatty acids play a role in sustaining the proliferation of FGF-stimulated SC-3 cells.

Animals↗