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K Oshima

Publications and source records attributed to K Oshima.

At least 19 recordsLinked to original sources
PubMed1999

Relationship between Fas-ligand expression on carcinoma cell and cytotoxic T-lymphocyte response in lymphoepithelioma-like cancer of the stomach.

The Fas/Fas-ligand (Fas-L) system is involved in the induction of apoptosis and mediates T-cell cytotoxicity. We investigated the Fas/Fas-L system and cytotoxic T lymphocytes (CTLs) in 30 lymphoepithelioma-like cancer of the stomach (LECS) in order to understand the immune evasion of the tumor cells. Epstein-Barr virus (EBV) was detected in 15 cases in 30 LECSs. The expressions of Fas and Fas-L in tumor cells, and TIA-1, CD4, CD8 and CD56 in lymphocytes were examined by immunohistochemical staining. Apoptosis of tumor cells and lymphocytes was detected by the terminal deoxynucleotidyl-mediated dUTP-nick end labeling method (TUNEL). Expression of Fas and Fas-L was detected in tumor cells in 10 and 17 LECS, respectively. CTL consisted predominantly of CD8 (CD8(+) > CD4(+)), whereas natural killer (NK) cells were detected in 4 cases only. In Fas-L-positive tumors, the TIA-1-positive lymphocyte count was significantly lower (p < 0.05) and the number of apoptotic lymphocytes was significantly higher (p < 0.05) than in Fas-L-negative cases. The number of TIA-1-positive lymphocytes in EBV(+) cases was significantly higher than that in the EBV(-) tumors (p < 0.05). The number of apoptotic tumor cells in EBV(+) tumors was significantly lower than in EBV(-) cases (p < 0.01). Our results suggest that in LECS, tumor cells expressing Fas-L may evade the immune attack by killing lymphocytes through the Fas/Fas-L system. However, in EBV(+) LECS tumors, our results indicate that a high number of CTL is associated with a reduction in the number of apoptotic tumor cells. Our findings indicate that the Fas/Fas-L system plays a role in immune evasion of tumor cells in EBV(+) tumors. Int. J. Cancer (Pred. Oncol.) 84:339-343, 1999.

Aged↗
PubMed1999

Lactation-dependent expression of an mRNA splice variant with an exon for a multiply O-glycosylated domain of mouse milk fat globule glycoprotein MFG-E8.

Expression of mRNA encoding MFG-E8, a milk fat-associated glycoprotein was investigated in mouse mammary gland. Two forms of mRNA, long and short variants, were shown to be expressed in the mammary tissue by RT-PCR analysis. Sequence analyses of these two variants and an isolated MFG-E8 gene segment indicated that the long and short mRNA variants resulted from an alternative splicing of a single pre-mRNA through in-flame inclusion and skipping of one exon, which encodes a proline/threonine (Pro/Thr)-rich domain. The long variant was expressed predominantly in mammary gland and the expression level was remarkably increased at late gestation and kept high during lactation. On the contrary, the short variant was detected ubiquitously in various tissues and its expression in the mammary gland was rather decreased in a lactation dependent manner. Expression of the long variant was also detected in a mouse mammary epithelial cell line, COMMA-1D, and enhanced by incubation with lactogenic hormones. Glycosylation inhibition analyses using tunicamycin and alpha-benzyl-GalNAc were conducted with COS7 cells transfected with plasmids expressing each mRNA variant, demonstrating that a fully glycosylated product of the long mRNA variant was not only N-glycosylated but also multiply O-glycosylated, whereas a product of the short one had only N-glycan(s). These results suggest that the alternative splicing plays a critical role for the mammary-specific and lactation-dependent expression of the MFG-E8 isoform and that the multiply O-glycosylated Pro/Thr-rich domain of this isoform is functionally important for formation of milk fat globules in mammary epithelial cells.

Alternative Splicing↗
PubMed1999

The Effect of FR167653 on Cerebral Ischemia-Reperfusion Injury After Retrograde Cerebral Perfusion in a Canine Model.

Retrograde cerebral perfusion (RCP) has recently been reported to be useful for the repair of aortic arch aneurysms. However, there is a possibility that RCP supplies a limited amount of blood to the brain [1] and ischemia-reperfusion injury may occur after RCP. FR167653 (FR) is characterized as a potent suppressant of interleukin-1beta and tumor necrosis factor-alpha. We investigated the role of FR in preventing cerebral ischemia-reperfusion injury after RCP in a canine model. A total of 12 mongrel dogs was divided into two groups: in the FR group (n = 6), FR167653 (1 mg/kg/hour) was continuously administered during the period of RCP and rewarming; in the control group (n = 6), a physiological saline solution was administered at the same dosage as the FR167653 during the same period. Following hypothermia (20 degrees C) using cardiopulmonary bypass and circulatory arrest, RCP was performed by infusing oxygenated blood via the bilateral internal maxillary veins for 60 minutes at a perfusion pressure of 25 mmHg. The cerebral blood flow (CBF), cerebral metabolic rate for glucose (CMRGlu) and oxygen (CMRO2), and excretion of carbon dioxide (ExCO2) were measured. These results were expressed as the percentage of change from baseline values established immediately after anesthesia. CBF was significantly (p < 0.05) higher in the FR group than in the control group at 40 (159 +/- 25% and 82 +/- 21%, respectively) and 60 minutes (177 +/- 30% and 83 +/- 14%, respectively) after RCP. The lactate/pyruvate ratio of blood returned from the brain tissues was significantly (p < 0.05) lower in the FR group than in the control group at 40 and 60 minutes after RCP. CMRGlu was significantly (p < 0.05) higher in the FR group than in the control group 60 minutes after RCP. There was no significant difference in CMRO2 and ExCO2 between the two groups. It is concluded that FR167653 appears to be effective in protecting the brain from ischemia-reperfusion injury after RCP.http://link.springer-ny.com/link/service/journals/00547/bibs/8n3p143.html

Journal Article↗
PubMed1999

The residual epiretinal membrane after vitrectomy for macular hole.

BACKGROUND: We retrospectively observed idiopathic macular holes in 63 eyes using a scanning laser ophthalmoscope, in order to study the relation between postoperative epiretinal membranes and closure of macular holes following vitrectomy. METHODS: The eyes were classified into three groups based on the degree of the postoperative epiretinal membranes. Group I consisted of 23 eyes with no epiretinal membrane remaining on the retina after vitrectomy. Group II consisted of 20 eyes in which epiretinal membranes were observed on the retina, but separate from the edge of the macular hole. Group III consisted of 20 eyes in which epiretinal membranes were observed at the edge of the macular hole. Using these three groups, we studied how postoperative epiretinal membranes were related to the closure of macular holes. RESULTS: All macular holes (100%) in groups I and II were closed following vitrectomy. In group III, 5 (25.0%) of 20 eyes had complete closure and 13 eyes (65.0%) had incomplete closure of the macular hole, while 2 eyes (10.0%) had re-opening of initially closed macular holes several months after vitrectomy. CONCLUSION: Residual postoperative epiretinal membranes at the edge of macular hole are responsible for primary failure of vitrectomy. Removal of epiretinal tissues around the macular hole is important for macular hole to be closed following vitrectomy.

Epiretinal Membrane↗
PubMed1999

Cardioprotective effects of Lazaroid U-74389G on ischemia-reperfusion injury in canine hearts.

BACKGROUND: Lazaroid, an inhibitor of iron-mediated lipid peroxidation, has been shown to reduce free radical-mediated injury after ischemia and reperfusion. The effect of Lazaroid U-74389G was investigated on ischemia-reperfusion injury of the heart through preservation and transplantation (Tx) in dogs. METHODS: Eleven pairs of adult mongrel dogs weighing 8.5 to 12 kg formed the recipient-donor combinations. Following electromechanical arrest of the heart using cardioplegia, the coronary vascular beds were washed out with a cold University of Wisconsin solution followed by 12-hour preservation and orthotopic Tx. Experimental animals were divided into 2 groups; 6 pairs formed the control group, and 5 formed the Lazaroid-treated group in which Lazaroid U-74389G at 10 mg/kg was administered intravenously 30 minutes before reperfusion of the heart. The cardiac function including cardiac output, left ventricular (LV) pressure, and LV dp/dt was assessed 2 hours after Tx by comparing it with the recovery rates (%) from cardiac function of donor dogs. Each transplanted heart was harvested for histological study. RESULTS: The recovery of cardiac function after Tx was significantly better in the Lazaroid-treated group than in the control group. Histologically, myocardial damage, evaluated by both light and transmission electron microscopy, was less evident in the Lazaroid-treated group than in the control group. CONCLUSION: Early cardiac function following Tx was significantly better and histological damage was less in the Lazaroid-treated group than in the control group, suggesting that Lazaroid U-74389G is effective in preventing ischemia-reperfusion injury after preservation and Tx.

Adenosine↗
PubMed1999

The laminin-derived peptide YIGSR (Tyr-Ile-Gly-Ser-Arg) inhibits human pre-B leukaemic cell growth and dissemination to organs in SCID mice.

The YIGSR (Tyr-Ile-Gly-Ser-Arg) laminin beta1 chain sequence has an inhibitory effect on tumour growth and the metastasis of melanoma and fibrosarcoma cells. In the present study, we investigated whether the multimeric YIGSR peptide (Ac-Y16) has an antiproliferative effect and/or prevents the metastasis of human pre-B acute lymphoblastic leukaemia cells (NALM6) in severe combined immune deficient (SCID) mice. In in vitro studies, Ac-Y16 significantly inhibited leukaemic cell colony formation and the invasion of NALM6 cells in a Matrigel-based assay. The tumour growth and leukaemic infiltration in peripheral tissues were also analysed in SCID mice 9 weeks after NALM6, Matrigel and Ac-Y16 were subcutaneously co-injected. The weight of the subcutaneous tumours was significantly suppressed by Ac-Y16 in a dose-dependent manner. Flow cytometry analysis showed that the leukaemic infiltration was significantly inhibited in all organs with 1.5-2.0 mg of Ac-Y16. Leukaemic infiltrations in the brain were inhibited with 0.5 mg of Ac-Y16, and those in brain and bone marrow were also inhibited with 1.0 mg of Ac-Y16. With Ac-S16, a control-scrambled peptide, the only significant inhibition of the leukaemic infiltration was observed in bone marrow at a much higher dose. These data suggest that the multimeric YIGSR peptide can inhibit the tumour growth and metastasis of leukaemic cells and may be useful as a potential therapeutic reagent for leukaemic infiltrations.

Actins↗
PubMed1999

Low rate of apoptosis and overexpression of bcl-2 in Epstein-Barr virus-associated gastric carcinoma.

AIMS: Epstein-Barr virus (EBV) has been demonstrated in about 10% of gastric carcinomas. However, the pathogenetic role of EBV in gastric carcinoma is uncertain. We compared the rate of apoptotic cell death, cell proliferation and the expression of apoptosis-related proteins in gastric carcinomas with or without EBV. METHODS AND RESULTS: Epstein-Barr virus was detected in 40 gastric carcinomas by EBV-encoded small RNA-1 in-situ hybridization. Apoptotic cell death, MIB-1, p53, bcl-2 and bcl-x were examined by the terminal deoxynucleotidyl-mediated dUTP-nick end labelling method and immunohistochemistry. We also included 40 age-, sex- and disease stage-matched EBV-negative cases as a control. The number of apoptotic cells was significantly lower in EBV-positive (20 +/- 15. 1/1000 cells) and bcl-2-positive (17 +/- 12.9/1000 cells) tumours than in EBV-negative (43 +/- 37.1) and bcl-2-negative tumours (38 +/- 32.1, P < 0.001, P < 0.001, respectively). bcl-2 immunostaining was significantly higher in EBV-positive tumours (24 cases) than in EBV-negative tumours (12 cases, P < 0.05). There was no significant difference in bcl-x and p53 expression between EBV-positive and -negative tumours. The number of MIB-1-positive cells in EBV-positive tumours (237 +/- 161/1000) was significantly lower than in EBV-negative tumours (480 +/- 208/1000 cells, P < 0.001). CONCLUSIONS: A low rate of apoptosis and high bcl-2 expression were recognized in EBV-positive gastric carcinomas, suggesting that bcl-2 protein is the main inhibitor of apoptosis in EBV-positive carcinomas. In addition, the low apoptotic and proliferative activities may reflect a low biological activity in EBV-positive gastric carcinomas.

Adult↗
PubMed1999

Establishment and characterization of a serous papillary adenocarcinoma cell line of the human ovary in a serum-free culture.

In order to clarify the biologic characteristics of serous papillary adenocarcinoma of the human ovary, we tried to establish a continuous cell line using four primary tumor specimens derived from four patients with such tumors. We also evaluated c-myc, MYCN and c-erbB2 gene amplification in the cultured cells, and the xenografts, as well as in these four primary tissue specimens by a Southern blot analysis. One continuous cell line, named as FU-OV-1, was established in a serum-free culture system and this line propagated continuously for 96 serial passages over a 2-year-period in vitro. FU-OV-1 reproduced and still maintained the characteristics of the original tumor. C-myc gene amplification was found in the FU-OV-1 cells, and the xenografts, as well as in only the primary tumor of FU-OV-1 out of the four primary serous papillary adenocarcinomas. However, neither MYCN amplification nor c-erbB2 amplification was observed in any tumor specimens including FU-OV-1 cells. In conclusion, FU-OV-1 is thus considered to be a useful system for studying the biological behavior of serous papillary adenocarcinoma in the human ovary. The results of this study suggest that c-myc gene amplification might thus be associated with the progression of this tumor both in vitro and in vivo.

Adult↗
PubMed1999

[TTV materno-infantile infection--a study on the TTV frequency in Japanese pregnant women and the natural history of TTV mother-to-infant infection].

We preliminarily describe the frequency of TTV in Japanese pregnant women, non-parenteral, postnatal materno-infantile transmission of TTV, and 2 cases in which infantile development of the TTV carrier-state seemed to have occurred by vertical infection. The sera of 85 hepatitis B, C and G-positive and 36 non-pathological pregnant Japanese women were screened for the presence of TTV DNA with a use of semi-nested PCR. The positive rates were 25.9 and 27.8%, respectively. No significant differences were gained between these two groups. Twenty-one infants were born to the TTV carrier women. Of them, 9 infants (42.9%) sero-converted to TTV DNA-positive after their age of 4 months. Among the infants who were breast-fed, the positive sero-conversion rate of TTV DNA tended to increase as the length of the breast feeding period increased. Serum AST/ALT levels stayed within normal upper limits in the 9 infants. This study indicates the frequent, and furthermore, certain possibility of non-parenteral (i.e., via breast milk), postnatal vertical infection of TTV.

Biomarkers↗
PubMed1999

Involvement of CYP2E1 as A low-affinity enzyme in phenacetin O-deethylation in human liver microsomes.

Phenacetin O-deethylation (POD) exhibits biphasic kinetics in human liver microsomes. Although cytochrome P-450 (CYP) 1A2 is responsible for the high-affinity component of POD, the enzyme(s) that catalyzes the low-affinity reaction is still unknown. We examined the roles of human CYPs in POD by using human liver microsomes and recombinant CYPs from baculovirus-infected insect cells. Of the recombinant CYPs studied, CYP1A2 showed the highest POD activity. CYP1A1, CYP2C19, CYP2D6, CYP2E1, and CYP3A4 also showed POD activity at 500 microM phenacetin. K(M) values of recombinant CYP1A2 and CYP2E1 (28 +/- 2 microM and 785 +/- 125 microM, respectively) were similar to those of the high- and low-affinity components of POD in pooled human liver microsomes (15 +/- 5 and 894 +/- 189 microM, respectively). Fluvoxamine (10 microM) and anti-CYP1A2 antibodies potently inhibited POD activity at 500 microM phenacetin in pooled human liver microsomes to 22.8 and 34.2% of controls, respectively. CYP2E1 inhibitors diethyldithiocarbamate and aniline also reduced POD activity. The combination of fluvoxamine (10 microM) and aniline (1 mM) further inhibited the residual POD activity not inhibited by fluvoxamine alone. Microsomal POD activity in 12 human livers in the absence of fluvoxamine was correlated with immunoquantified CYP1A2 levels (r = 0.961, p <.001) and, in the presence of 10 microM fluvoxamine, was correlated with immunoquantified CYP2E1 levels (r = 0.589, p <.01) or chlorzoxazone 6-hydroxylase activity (r = 0.823, p <.001). These results suggest that CYP2E1 is responsible for the low-affinity component of POD in human liver microsomes.

Analgesics, Non-Narcotic↗
PubMed1998

Cerebrosides A and C, sphingolipid elicitors of hypersensitive cell death and phytoalexin accumulation in rice plants.

When plants interact with certain pathogens, they protect themselves by generating various chemical and physical barriers called the hypersensitive response. These barriers are induced by molecules called elicitors that are produced by pathogens. In the present study, the most active elicitors of the hypersensitive response in rice were isolated from the rice pathogenic fungus Magnaporthe grisea, and their structures were identified as cerebrosides A and C, sphingolipids that were previously isolated as inducers of cell differentiation in the fungus Schizophyllum commune. Treatment of rice leaves with cerebroside A induced the accumulation of antimicrobial compounds (phytoalexins), cell death, and increased resistance to subsequent infection by compatible pathogens. The degradation products of cerebroside A (fatty acid methyl ester, sphingoid base, and glucosyl sphingoid base) showed no elicitor activity. Hydrogenation of the 8E-double bond in the sphingoid base moiety or the 3E-double bond in the fatty acid moiety of cerebroside A did not alter the elicitor activity, whereas hydrogenation of the 4E-double bond in the sphingoid base moiety led to a 12-fold decrease in elicitor activity. Furthermore, glucocerebrosides from Gaucher's spleen consisting of (E)-4-sphingenine and cerebrosides from rice bran mainly consisting of (4E,8E)-4,8-sphingadienine and (4E,8Z)-4,8-sphingadienine showed no elicitor activity. These results indicate that the methyl group at C-9 and the 4E-double bond in the sphingoid base moiety of cerebrosides A and C are the key elements determining the elicitor activity of these compounds. This study is the first to show that sphingolipids have elicitor activity in plants.

Anti-Infective Agents↗
PubMed1998

Low-vacuum, low-voltage scanning electron microscopy of poly(methyl methacrylate) intraocular lenses.

PURPOSE: To evaluate the usefulness of low-vacuum, low-voltage scanning electron microscopy (LVSEM) in examining the surfaces of intraocular lenses (IOLs) without preparation. SETTING: In vitro laboratory experiment. METHODS: Six commercially available IOLs made of poly(methyl methacrylate) (PMMA) and one explanted PMMA IOL were evaluated with LVSEM without sputter coating. Sham surgical maneuvers were performed on some IOLs and the surface changes observed. RESULTS: Smooth surfaces of IOL optics and haptics, relatively sharp edges of optic holes, and irregularities at the optic/haptic junction were clearly observed. Crystalline deposits were seen on the surfaces after the IOLs were dipped and dried in saline solution. Scratches and marks were observed after they were grasped with a forceps. CONCLUSIONS: Low-vacuum, low-voltage scanning electron microscopy is a time-saving procedure that can be used by inexperienced investigators. The resolution under relatively low magnification appeared to be satisfactory for evaluating the IOL surface.

Electricity↗
PubMed1998

Donor lymphocyte transfusion for the treatment of Epstein-Barr virus-associated lymphoproliferative disorder of the brain.

EBV-associated lymphoproliferative disorder (LPD) is a rare but serious complication in marrow transplant recipients. A 31-year-old Japanese woman in the second chronic phase of CML received an allogeneic BMT from her HLA 2-locus-incompatible 62-year-old father. Around day +200, she developed EBV-LPD of the right parieto-temporal lobe which caused slowly progressive left hemiparesis. Two courses of donor lymphocyte transfusions (DLT) of 10(6)CD3+ T cells/kg of body weight failed to suppress her central nervous system (CNS) EBV-LPD. The patient died of recurrent blastic crisis of CML. This case suggests that DLT may be ineffective for the treatment of CNS EBV-LPD.

Adult↗