Biomedical subjects

Hiroshi Nagata

Publications and source records attributed to Hiroshi Nagata.

At least 19 recordsLinked to original sources

PubMed2006

Low-dose oxaliplatin enhances the antitumor efficacy of paclitaxel in human gastric cancer cell lines.

BACKGROUND: The enhanced antitumor effect of paclitaxel when used with oxaliplatin in gastric cancer is reported, however the underlying biological mechanism is unknown. METHODS: We tested the cytotoxic activity, apoptosis, and mitotic catastrophe of paclitaxel and oxaliplatin in MKN-28 and MKN-45 gastric cancer cell lines. The modulation of survivin expression was determined by Western blotting. RESULTS: WST-1 assay indicated that paclitaxel plus oxaliplatin showed better cytotoxicity than paclitaxel alone, even when low concentrations of oxaliplatin were used. Flow cytometry analysis revealed significantly greater increases in apoptotic cells after treatment with paclitaxel followed by low-dose oxaliplatin (1 microM) than after any single-reagent regimen in the MKN-45 cell line. In MKN-28, a difference existed only between combination treatment and oxaliplatin treatment. Morphologic examination showed that the cells undergoing mitotic catastrophe were highest in the combination groups in the both cell lines. Downregulation of survivin expression was found by Western blotting with treatment by paclitaxel, oxaliplatin, or their combination. CONCLUSION: Our findings suggest that the mechanism of enhanced cytotoxicity might be through enhanced mitotic catastrophe and apoptosis, which is possibly due to chemotherapy-induced downregulation of surviving. The combination of paclitaxel and low-dose oxaliplatin should be incorporated into the design of a clinical trial.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed2006

Maintenance of in vitro granulosa cell function by adenoviral mediated follicle stimulating hormone receptor gene transduction.

PURPOSE: To maintain in vitro granulosa cell function by adenoviral-mediated FSHR gene transduction. METHODS: Rat granulosa cells were cultured and transduced with adenovirus carrying FSHR gene. The number of receptors and the rate of steroidogenesis were assessed. RESULTS: The number of FSHR on the granulosa cells was 4,874 per cell immediately after extraction, it was 2,176 by the third day, and had further reduced to 693 by the seventh day. On the third day of culture, the amount of production of estradiol by FSH stimulation also decreased to about one-quarter of the first day's quantity. Compared to the untransduced granulose cells, when the cells contained FSHR gene, the FSHR expression and steroidogenesis were both enhanced (2,176 vs. 7,206 per cell (p<0.001) and 192 vs. 5940 pg/mL (p<0.01), respectively). CONCLUSION: Granulosa cell functions can be maintained or increased by novel gene therapy. This can be a useful component of assisted reproductive therapy.

Adenoviridae↗

PubMed2006

Significance of 32-kDa cathepsin L secreted from cancer cells.

It is recognized that many cancer cells secrete cathepsin L to degrade the components of extracellular matrices and basement membranes, thus promoting tumor invasion and metastasis. However, very little information is available concerning the secreted forms of cathepsin L and their possible role in human cancer. We initially demonstrated that approximately 10-fold higher mature cathepsin L activity was secreted in a medium of human fibrosarcoma (HT 1080) cells, compared with their intracellular activity. A 32-kDa major-activity band, together with a 41-kDa faint-activity band, was detected in the medium by our newly developed gelatin zymography. The two forms were further confirmed to be cathepsin L by immunoblot analysis. Both were apparently secreted directly from the cells, as neither was affected when the cells were cultured in the presence of various kinds of proteinase inhibitors. Human tumor necrosis factor-alpha (TNF-alpha) stimulated not only the production of the 32-kDa cathepsin L, but also its secretion. Moreover, the 32-kDa cathepsin L activities in 3 colon and 2 lung cancer tissues were significantly higher than in normal tissues. Based on the foregoing, there are good reasons to speculate that the 32-kDa cathepsin L found in HT 1080 cell medium is involved in cancer invasion and metastasis.

Cathepsin L↗

PubMed2006

Judgments of grammaticality of Japanese simple sentences involving two arguments in a whole-part relation: a further examination of Chomsky's principle of Full Interpretation.

Adult Japanese speakers judged the grammaticality of simple ungramatical sentences involving two arguments, each related with a single verb. The arguments were attached to the same case marker playing the same thematic role in the sentences. Thus the sentences violated Chomsky's principle of Full Interpretation. The two arguments were manipulated such that, on the one hand, one argument (the part-argument) constituted a part of the other argument (the whole-argument) and that, on the other, a part-argument either preceded or followed a whole-argument. Participants rated the sentences using either a conventional 7-point rating scale or magnitude estimation. Findings showed that irrespective of rating method sentences in which the whole-argument preceded the part-argument were judged more grammatical than sentences in which the part-argument preceded the whole-argument. Such an empirical phenomenon is inconsistent with the prediction derived from Chomsky's principle of Full Interpretation, while interestingly it is consistent with the grammar of classical Japanese used about 900 years ago.

Humans↗

PubMed2006

Attenuating effect of Myakuryu on mesenteric microcirculatory disorders induced by ischemia and reperfusion.

Myakuryu (MR) is a newly developed herbal medicine composing Crataegue oinnatifida bge (COB), Panax notoginseng (PN) and Ginkyo biloba (GB). To examine the effectiveness of MR, we investigated its effects on rat mesenteric microcirculatory injury induced by ischemia/reperfusion (I/R). The mesenteric microcirculation of ileocecal portion of a male Wistar rat was observed through an inverted-type intravital microscope assisted with a charge-coupled devise (CCD) camera. Mesenteric I/R was conducted by a ligation of the mesenteric artery and vein (10 min) and subsequent release of the occlusion. We measured venular diameter, the number of adherent leukocytes, dihydrorhodamine 123 (DHR) fluorescence as an indicator of oxidative stress and mast cell degranulation, with or without MR extract (0.4 g/kg b.w.) via an orogastric tube 1 hr before I/R. The diameters of the observed mesenteric venules were not changed after the mesenteric I/R. MR had no effect on venular diameter. The leukocytes adhering to the post-capillary venular walls started just after reperfusion, and increased thereafter. The increased number of adherent leukocytes was significantly reduced by treatment with MR. DHR fluorescence ratio was significantly increased along the venular wall. MR attenuated the increased oxidation. The mesenteric I/R induced mast cell degranulation. The increase in mast cell degranulation was inhibited by MR. In conclusion, oral administration of MR attenuates I/R-induced microvascular damages in rat mesentery. MR has a therapeutic potential for prevention of I/R-related microvascular injury.

Animals↗

PubMed2006

[Clinical pathway for bleeding peptic ulcers].

We devised and evaluated a clinical pathway (CP) protocol for patients with bleeding peptic ulcers (BPU). Patients without severe comorbidities, who had been diagnosed with BPU and who had undergone endoscopic treatment, were enrolled in our study. The CP adaptation rate for BPU patients was 78.8% (89/113). The variance rate was 13.5% (12/89). The median length of admission was 10.0 +/- 4.6 days (n = 78) before and 7.4 +/- 2.9 days (n = 77) after introducing CP. Our CP for BPU was safe and resulted in shorter hospital stays and, therefore, cost reductions. In elder patients, our CP was also successful, but the variance rate was higher than in younger patients.

Adult↗

PubMed2006

[A case of intrahepatic cholangiocarcinoma effectively treated by hepatic arterial infusion chemotherapy].

The patient was a 50-year-old woman who suffered from gastric discomfort. She was first diagnosed as intrahepatic cholangiocarcinoma with hepatic, paraaortic lymphnodal and bone metastasis. Initial systemic chemotherapy using gemcitabine (GEM) and 5-FU failed to control the disease activity. Then she was given GEM and cisplatin (CDDP) combination chemotherapy. The response was assessed as stable disease (SD), but grade 4 leukopenia was seen. Then systemic therapy using GEM, and hepatic arterial infusion therapy with CDDP, l-leucovorin and 5-FU were continued biweekly. Partial response (PR) was achieved six months later, and her disease status was maintained as SD. This hepatic arterial infusion chemotherapy would be safe and feasible as therapy for inoperable intrahepatic cholangiocarcinoma.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed2005

Expression of Musashi-1 in the rat stomach and changes during mucosal injury and restitution.

Musashi-1 is involved in maintenance of neural stem cells. In the rat stomach, we found some cells in the luminal compartment of the mucosa that stained positively for Musashi-1. These cells were distinct from other cells of epithelial lineage, except for parietal cells, and coexpressed HES5. The Musashi-1-positive cells exfoliated after damage, while Musashi-1 expression in neck cells were upregulated, and proliferating cells diminished before reappearing and increasing in number thereafter. We conclude that a subpopulation of parietal cells acts as a source of Musashi-1, which contributes to rapid re-epithelization by restoration of stem cells and regulation of cell differentiation.

Animals↗

PubMed2005

Effects of testosterone on cancellous bone, marrow adipocytes, and ovarian phenotype in a young female rat model of polycystic ovary syndrome.

OBJECTIVE: To investigate the effects of testosterone on cancellous bone and marrow adipocytes in a young female rat model of polycystic ovary syndrome (PCOS). DESIGN: Comparative and controlled study. SETTING: University animal research laboratory. PATIENT(S): Fifty-one Sprague-Dawley rats. INTERVENTION(S): The rats were divided into four groups based on the day of testosterone propionate (0.1 mg/weight (g)) injection: no testosterone treatment (control group, C); injected on the ninth day after birth (9D); injected 4 weeks after birth (4W); and injected 8 weeks after birth (8W). About 16 weeks after birth, all animals were killed. MAIN OUTCOME MEASURE(S): Bone mineral density (BMD) and bone and fat histomorphometry for the proximal tibia and serum hormonal parameters were measured. RESULT(S): The ovaries of group 9D showed many cystic follicles without corpora lutea. The BMD of group 9D (0.309 +/- 0.023 g/cm2) was significantly higher than the other groups groups (CONT, 0.262 +/- 0.017; 4W, 0.256 +/- 0.017; 8W, 0.256 +/- 0.022 g/cm2; P < .0001). Based on bone histomorphometry, group 9D had a higher bone volume (BV/TV), lower bone formation (OV/BV, OS/BS, sLS/BS, MAR, BFR/BS), lower bone resorption (ES/BS, Oc.S/BS), and lower rate of longitudinal growth compared to the other groups. Based on fat histomorphometry, group 9D had a lower bone fat volume and number of fat cells in the bone marrow compared to the other groups. On the other hand, groups 4W and 8W showed similar values of bone and fat histomorphometric parameters to group C. CONCLUSION(S): Female rats receiving testosterone within nine days of birth develop polycystic ovaries, high bone volume, low bone turnover, and lower fat content in the bone marrow.

Adipocytes↗

PubMed2005

Suppression of inflammation by dexamethasone prolongs adenoviral vector-mediated transgene expression in murine nasal mucosa.

CONCLUSION: The results of this study demonstrate that suppression of inflammation by dexamethasone attenuates the host immune response against adenoviral-mediated gene transfection and thereby prolongs transgene expression in murine nasal mucosa. OBJECTIVES: Gene transfer using a recombinant adenovirus is a good tool for research and clinical applications, but the immune response to adenoviral vectors can induce inflammation and loss of transgene expression in transfected tissues. In this study we investigated the effects of dexamethasone-induced immunosuppression on adenovirus gene transfer in the nasal mucosa of the mouse. MATERIAL AND METHODS: We administered the recombinant adenovirus Ax1CAlacZ, which encodes Escherichia coli beta-galactosidase (lacZ gene), to the nasal mucosa of mice treated with or without i.p. dexamethasone and evaluated the expression of the lacZ gene on Days 2, 4, 7, 14 and 28. The nasal mucosa was dissected out, and the mRNA level was measured using a LightCycler. The expression of the exogenous beta-galactosidase was detected by means of histochemistry. RESULTS: Dexamethasone treatment significantly increased the mRNA level compared with that in the controls at Days 4, 7 and 14. Histochemistry showed that the expression of beta-galactosidase protein persisted in the dexamethasone-treated mice at Days 7 and 14 but had diminished almost to nothing in the control group.

Adenoviridae↗

PubMed2005

Activity of gelatins to induce secretion of a variety of cytokines from murine peritoneal exudate macrophages.

Previously, we observed that liquid form bovine bone (BB) gelatin stimulates murine spleen cells to proliferate in vitro. In this study, activity of BB gelatin to stimulate murine-adherent peritoneal exudate cells (PEC) to secrete cytokines has been examined. Quantitatively, BB gelatin stimulated adherent PEC of C3H/HeN mice to secrete interleukin (IL)-12 (+p40), TNF-alpha, and IL-6 but not IL-1beta, IL-2, IL-10, and IFN-gamma. Qualitatively, BB gelatin-induced secretion of KC, MIP-2, MCP-1, RANTES, and MIP-1a as well as IL-6 but not 6Ckine, CTACK, Eotaxin, G-CSF, GM-CSF, IL-2,-3,-4,-5,-9,-10,-12,-13,-17, Leptin, IFN-gamma, SCF, sTNFri, TARC, TNF-alpha, TIMP-1, Tpo, and VEGF. BB gelatin acted on adherent PEC of C3H/HeN mice but not C3H/HeJ mice, which lack Toll-like receptor 4. Polymyxin B, a LPS antagonist, did not inhibit the activity of BB gelatin. Lipopolysaccharide (LPS) but not BB gelatin induced secretion of an appreciable amount of mIL-1beta. These results suggest that the activity of BB gelatin is not attributed to contamination of LPS but BB gelatin itself. It was also suggested that BB gelatin stimulated adherent PEC to newly produce and secrete cytokines.

Animals↗

PubMed2005

AICAR, an AMPK activator, has protective effects on alcohol-induced fatty liver in rats.

BACKGROUND: Previous work with metformin has shown that this antidiabetic agent improves nonalcoholic fatty liver in ob/ob mice. AMP-activated protein kinase (AMPK) is one of the major cellular regulators of lipid and glucose metabolism, and reportedly mediates the beneficial metabolic effects of metformin. In this study, we examined the effects of 5-aminoimidazole-4-carboxamide-1-beta-D-ribofuranoside (AICAR), an AMPK activator, on an experimental model of ethanol-induced hepatic steatosis. METHODS: Rats were randomly divided into three groups: (A) rats fed ethanol-containing liquid diet for six weeks; (B) rats pair-fed ethanol-containing liquid diet for six weeks, during the last three weeks of which they were subcutaneously injected with 0.5 mg AICAR/g body weight per day; (C) rats pair-fed isocaloric liquid diet without ethanol for six weeks. At the end of the six-week period, the animals were sacrificed. Serum and liver specimens were analyzed using biochemical and histologic methods, as well as real-time PCR. RESULTS: Chronic ethanol feeding resulted in fatty liver both histologically and biochemically, whereas AICAR administration attenuated the degree of change in the liver. AICAR also decreased the hepatic sterol regulatory factor binding protein-1c (SREBP-1c) and reduced fatty acid synthase (FAS) expression; these changes led to reduced triglyceride synthesis in rat livers. Furthermore, detection of 4-hydroxy-2-nonenal (4-HNE)-protein adducts showed that the AICAR treatment also decreased the products of lipid peroxidation. CONCLUSION: In this preclinical rat model, AICAR, an AMPK activator, appears to protect the liver from fatty changes associated with chronic alcohol use. As such, AICAR may have a role in the treatment and prevention of alcohol-induced fatty liver.

AMP-Activated Protein Kinases↗

PubMed2005

[A case of advanced gastric cancer with lymphangitis carcinomatosa after operation of Krukenberg tumor treated by TS-1 plus CPT-11 as third-line chemotherapy].

Chemotherapies for recurrent gastric cancer have not yet been established. Here we report a case of type 4 gastric cancer associated with lymphangitis carcinomatosis which became refractory to the previous chemotherapies. The case was a 40-year-old woman. She had been diagnosed with gastric cancer after a Krukenberg tumor operation. Chemotherapies (TS-1 plus CDDP as first-line, and TS-1 plus taxanes as second-line) were performed, and a partial response was achieved. Disease activity has been well controlled until this time. Since recurrence of left pleural effusion and lymphangitis carcinomatosis was recognized, we changed the chemotherapy TS-1 plus CPT-11. Pleural effusion decreased and lymphangitis carcinomatosis improved. The serum CA 19-9 level rose transiently after CPT-11 administration, and tended to fall at the second week of chemotherapy. However, the patient died 2 years 4 months after the onset. TS-1 plus CPT-11 combination chemotherapy would be effective for lymphangitis carcinomatosis and also useful as third-line chemotherapy for recurrent gastric cancer.

Adult↗

PubMed2004

Limited capability of regional lymph nodes to eradicate metastatic cancer cells.

The capacity of lymph nodes to eradicate cancer is a controversial issue. The purpose of this study was to determine the interplay between tumor growth and host resistance at early stages of lymph node metastasis. A metastasis model was made in the rat mesenteric lymph node, and migration of cancer cells was visualized in vivo. The lymph node was removed for histologic analysis and cytokine measurement. Migrant cancer cells were initially arrested in the marginal sinus. After an initial increase, the number of cancer cells in the marginal sinus declined until 48 hours after inoculation. Germinal centers and lymphoid cells in the medulla proliferated before 48 hours. ED3(+) macrophages incorporated apoptotic cancer cells, but significant cancer proliferation occurred after 4 days. Lymph nodes depleted of macrophages were massively invaded by cancer cells. Tumor necrosis factor alpha and interleukin (IL)-1beta in the nodes transiently increased after 1 hour and 3 hours, respectively, and were expressed in ED3(+) and ED2(+) macrophages, respectively. These changes were followed by a transient increase in IL-2. Interferon-gamma and IL-12 did not increase during the early stages of metastasis, but they decreased after 48 hours. In conclusion, the marginal sinus constitutes a mechanical barrier against cancer cell passage. Early pathological manifestations in the regional lymph node are consistent with those in cancer patients with improved survival. Parasinus macrophages play a role in the transient antimetastatic capability of the node, and cytokines secreted by these cells increased at the early stages of metastasis. Deterioration of cytokine induction may be responsible for subsequent cancer proliferation.

Animals↗

PubMed2004

Effects of adenoviral vector-mediated BDNF expression on the bulbectomy-induced apoptosis of olfactory receptor neurons.

The expression of adenoviral vector (Ad)-mediated lacZ and brain-derived neurotrophic factor (BDNF) in mouse olfactory epithelium (OE) was examined, and the effect of BDNF on the survival of the bulbectomized OE was evaluated. A recombinant adenovirus, Ax1CAlacZ, was administrated into the mouse OE after bulbectomy, and the expression of a transferred E. coli beta-galactosidase (beta-gal) gene was confirmed by X-gal staining. The expression and effects of exogenous BDNF in the OE after bulbectomy were examined using immunohistochemistry and the TUNEL method. The adenoviral vector-mediated expression of beta-gal in the mouse OE was detectable for up to 14 days after bulbectomy in vivo. The Ad-mediated expression of BDNF was also observed in the OE after bulbectomy. Exogenously induced BDNF suppressed the degenerative changes of bulbectomized OE. TUNEL staining indicated that the exogenous BDNF enhanced the survival of the bulbectomized OE by inhibiting apoptosis. Ad-mediated expression of BDNF in the mouse nasal mucosa alleviated degenerative changes in bulbectomized OE. Ad-mediated transfer of neurotrophic factors might be applicable in the treatment of olfactory disorders.

Adenoviridae↗

PubMed2004

Autoimmune pancreatitis with pseudocysts.

A 47-year-old woman was admitted to our hospital with complaints of fever, upper abdominal pain, and back pain. The serum amylase, C-reactive protein (CRP), and IgG (especially IgG4) were elevated, and abdominal computed tomography (CT) revealed diffuse enlargement of the pancreas and pseudocysts. Endoscopic retrograde pancreatography (ERP) revealed diffuse irregular narrowing of the main pancreatic duct. Histopathological examination of the pancreatic tissue showed fibrotic change with lymphocytic infiltration. Based on these findings, we diagnosed this case as a case of autoimmune pancreatitis. This case also fully satisfied the diagnostic criteria for autoimmune pancreatitis established by the Japan Pancreas Society in 2002. Few reports have been published on cases of autoimmune pancreatitis complicated by the formation of pseudocysts in the pancreas. We, therefore, report this case here to emphasize that cases of autoimmune pancreatitis can be complicated by the development of pseudocysts.

Abdominal Pain↗

PubMed2004

Effect of vitamin D receptor and estrogen receptor gene polymorphism on the relationship between dietary calcium and bone mineral density in Japanese women.

In a longitudinal analysis of the results of bone mineral density (BMD) screenings conducted in local communities, we examined the effect of lifestyle improvements on BMD and investigated the influence of allelic variations of the vitamin D receptor ( VDR) and estrogen receptor ( ER) genes. The subjects were 484 women (age, 24-80 years) who underwent BMD screenings at least twice between 1994 and 2002. We conducted BMD measurements of the lumbar spine by dual-energy X-ray absorptiometry and performed a simple questionnaire survey of lifestyle factors. Women receiving pharmacotherapy, or those with bone fractures, were excluded, leaving 338 women eligible for the study. They were retrospectively divided into three groups: (i) premenopause, women who were at least 5 years preceding menopause; (ii) perimenopause, women who were within 5 years before or after menopause; and (iii) postmenopause, women who were at least 5 years past menopause. There was no correlation at all between improvements of lifestyle factors (i.e., calcium intake from dairy products and time spent walking) and fluctuations in lumbar-spine BMD after 1, 3, or 5 years in the pre-, peri-, and postmenopausal groups. For women in the postmenopausal group, the PP genotype for the ER gene correlated with a significantly higher initial BMD than those with the Pp and pp genotypes ( P = 0.04). After 3 years, presence of the TT genotype of Taq I of VDR gene polymorphism exhibited positive correlations ( r = 0.29, P = 0.03) with the improvements in calcium intake and in lumbar spine BMD for the perimenopausal group, whereas the Tt genotype showed negative correlations ( r = -0.48, P = 0.04). After 1, 3, and 5 years, presence of the Tt genotype showed a tendency toward a negative correlation with the increases in calcium intake and in lumbar spine BMD for the pre- and perimenopausal groups, although almost of these were not significantly different. In this study, we could not prove a positive correlation between the improvement of lifestyle and the fluctuation of BMD within a 5-year timeframe, although the polymorphisms within the VDR gene may have some influence.

Adult↗

PubMed2004

Association of vitamin D and estrogen receptor gene polymorphism with the effects of longterm hormone replacement therapy on bone mineral density.

We longitudinally studied whether vitamin D receptor (VDR) and estrogen receptor (ER) gene polymorphisms in Japanese women influenced the effect of longterm hormone replacement therapy (HRT) on bone mineral density (BMD) in the lumbar spine. The 81 subjects were aged 40 to 64 years (mean +/- SEM, 49.5 +/- 0.6 years), and had received sequential or continuous HRT regimens, including 0.625 mg of conjugated equine estrogen and 2.5 to 5 mg of medroxy-progesterone acetate, for at least 3 years. Genomic DNA was extracted from blood cells, and analyzed for restriction fragment length polymorphism, using the restriction endonucleases Taq I, Apa I, and Fok I for VDR, and Pvu II and Xba I for ER. At 1 year, subjects with a Taq I genotype of TT (i.e., site absent) showed a significantly greater increase in BMD with treatment (DeltaBMD) than subjects with the Tt genotype (2.6 +/- 0.5% vs -0.8 +/- 1.4%; P = 0.016). A small difference between genotypes remained at 2 years (3.8 +/- 0.6% vs 0.8 +/- 1.6%; P = 0.069), but no significant difference between genotypes was seen at 3 years. In multiple regression analyses, DeltaBMD at 1 year was significantly affected by VDR- Taq I, Apa I, and ER- Pvu II genotypes and by age at treatment initiation, although at 3 years or more, DeltaBMD was significantly affected only by age. These results indicate that Taq I VDR gene polymorphism predicted the effect on lumbar BMD for the first year of HRT in Japanese women, and that the differences in BMD versus the polymorphism disappeared if the treatment was continued for over 2 years.

Bone Density↗