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Biomedical subjects

S Arai

Publications and source records attributed to S Arai.

At least 181 records · Page 10Linked to original sources
PubMed1996

Induction of tumor necrosis factor alpha (TNF alpha) and enhancement of HIV-1 replication in the J22HL60 cell line by Mycoplasma penetrans.

Mycoplasma penetrans isolated from clinical specimens of AIDS patients showed potent activity in tumor necrosis factor alpha (TNF alpha) production in THP-1, U937 and J22HL60 cell lines, and in the enhancement of HIV-1 replication in a dormantly-infected J22HL60 cell line as compared with the activities of other mycoplasmas. Both activities were found in the methanol layer but not in the chloroform layer of the membrane extracted by the Bligh-Dyer method. TNF alpha production was observed in the peritoneal macrophages from both lipopolysaccharide-responsive and -unresponsive mouse strains, and was not inhibited by polymyxin B. The induction of TNF alpha production and enhancement of HIV-1 replication were strongly inhibited by Concanavalin A-Sepharose. The inhibitory effect of Concanavalin A-Sepharose was partially prevented by sugars in the order methyl-alpha-D-mannopyranoside and methyl-alpha-D-glucopyranoside but not methyl-alpha-D-galactopyranoside. Anti-human TNF alpha antibody, however, did not reduce the activity of the methanol layer to enhance HIV-1 replication, suggesting that the methanol layer could enhance HIV-1 replication directly. These results suggest that the carbohydrate derived from M. penetrans might be responsible for the progression of HIV-1 infection.

Antibodies↗
PubMed1996

Proteins of 30 and 36 kilodaltons, membrane constituents of the Staphylococcus aureus L form, induce production of tumor necrosis factor alpha and activate the human immunodeficiency virus type 1 long terminal repeat.

We have previously demonstrated that the membrane of the Staphylococcus aureus L form induced tumor necrosis factor alpha (TNF-alpha) from murine macrophages. In this study, we purified two proteins which induce TNF-alpha production from a human monocytic cell line, THP-1, and murine macrophages. These molecules were purified from delipidated membranes by deoxycholic acid extraction, two-step anion-exchange chromatography, and preparative electrophoresis. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the purified proteins showed for each a single band with a molecular mass of 30, and 36 kDa. These proteins were heat stable. Polymyxin B did not affect the production of TNF-alpha induced by these proteins. Furthermore, these proteins induced comparable levels of TNF-alpha in both lipopolysaccharide-responsive and -nonresponsive mouse macrophages. Pretreatment of murine macrophages with gamma interferon enhanced 30- and 36-kDa protein-mediated TNF-alpha production. The 30-kDa protein showed lethal toxicity to D-galactosamine-treated mice. The 30- and 36-kDa proteins stimulated the human immunodeficiency virus type 1 long terminal repeat in a monocytic cell line but not a T-cell line. This effect appeared to be mediated through the induction of nuclear factor kappaB. These results indicate that the 30- and 36-kDa proteins, membrane constituents of the S. aureus L form, may play a role in S. aureus infection and/or in human immunodeficiency virus type 1-infected individuals.

Animals↗
PubMed1996

Hereditary caeruloplasmin deficiency: clinicopathological study of a patient.

A 58 year old patient with dementia, oral dyskinesia, and diabetes mellitus is described. He had an undetectable concentration of serum caeruloplasmin, as an autosomal recessive trait. Brain MRI disclosed a pronounced hypointensity in the bilateral putamina, caudate, and dentate nuclei on both T1 and T2 weighted images. Pathological findings were mainly in those regions of the brain and consisted of neuronal cell loss with gliosis, heavy iron deposition, and spheroids. Visceral organs also had iron deposition, especially severe in the liver and pancreas. The present patient and other recorded cases constitute a clinicopathological entity of hereditary caeruloplasmin deficiency, different from Wilson's disease.

Brain↗
PubMed1996

Isolation and identification of compounds from Brazilian propolis which enhance macrophage spreading and mobility.

Brazilian propolis is known to induce the activation of murine effector cells. We isolated and identified six compounds from a water-soluble extract of Brazilian propolis, all of which have enhancing effects on the spreading and mobility of murine macrophages. These compounds were identified as caffeoylquinic acid-derivatives, namely, 5-caffeoylquinic acid (1), chlorogenic acid (2), 4-caffeoylquinic acid (3), 4,5-dicaffeoylquinic acid (4), 3,5-dicaffeoylquinic acid (5) and 3,4-dicaffeoylquinic acid (6).

Animals↗
PubMed1996

Structural organization of the gene encoding corn cystatin.

A genomic DNA clone encoding corn cystatin, a cysteine proteinase inhibitor of corn, was isolated from a lambda EMBL3 phage genomic library. The genomic DNA clone spans approximately 2.2 kb and consists of three exons and two introns. The exon number and the intron breakpoints coincide with those of the genes for two types of oryzacystatin.

Amino Acid Sequence↗
PubMed1996

Modification of wheat flour with bromelain and baking hypoallergenic bread with added ingredients.

Based on the wheat glutenin IgE-binding epitope, Gln-Gln-Gln-Pro-Pro, a practical method is proposed for the production of hypoallergenic wheat flour. Bromelain was found effective for decomposing the epitope structure. In practice, soft flour was mixed with water dissolving bromelain and the mixture was incubated at 37 degrees C for 4 h. The result of IgE-ELISA (enzyme-linked immunosorbent assay) suggested negative allergenicity. A mixture of bromelain-modified flour, glucose, citric, acid, a surfactant and sodium hydrogen carbonate was baked to produce hypoallergenic bread, resembling English muffins.

Amino Acid Sequence↗
PubMed1996

Inhibitory effect of arphamenine A on intestinal dipeptide transport.

Arphamenine A, an Arg-Phe analog without a peptide bond, has been reported to be a possible inhibitor of the peptide transporter [H. Daniel and S.A. Adibi, FASEB J., 8, 753 (1994)]. The present study demonstrated that arphamenine A is not a real inhibitor, but is a substrate for the transporter, being transported transepithelially under a proton gradient. The substrate specificity of the peptide transporter was wider than expected.

Biological Transport, Active↗
PubMed1996

Studies on functional foods in Japan--state of the art.

This paper pinpoints the "tertiary" function of foods which, different from the conventional "primary" and "secondary" functions that are related to nutrition and preference, respectively, is understood to be directly involved in the modulation of our physiological systems such as the immune, endocrine, nerve, circulatory, and digestive systems. Insights into this newly defined function are particularly important in that the intake of some physiologically functional constituents of foods could be effective in preventing diseases that may be caused by disorders in these physiological systems. Technologically, it has become feasible to design and produce physiologically functional foods (simply, functional foods) that are expected to satisfy in whole or in part a today's demand for disease prevention by eating. Such public expectations are reflected in the activation and development of systematic, large-scale studies on foods as seen in "Grant-in-Aid" research sponsored by the Ministry of Education, Science, and Culture. Meanwhile, the Ministry of Health and Welfare has initiated a policy of officially approving functional foods in terms of "foods for specified health uses" as defined by new legislation. Up to now (October 1995), 58 items have thus been approved. The first was a hypoallergenic rice product approved as of June 1, 1993. Here I discuss details of studies on rice-based functional foods. Other basic and applied studies directed toward the tertiary function, with future perspectives for functional foods, are also discussed.

Amino Acid Sequence↗
PubMed1996

Apoptosis in the chicken bursa of fabricius induced by X-irradiation.

Immature B lymphocytes in the chicken bursa of Fabricius have previously been reported to undergo apoptosis by low doses of ionizing radiation. In the present study, newly hatched chickens were subjected to whole-body X-irradiation, and the bursa of Fabricius was examined at various postirradiation times by light and electron microscopy to obtain information on the change of ultrastructure of irradiated bursal cells as well as on the time course and dose-response for the induction of apoptosis. Histological examination by light microscopy showed that pyknotic cells started to increase in the bursa within a few hours after irradiation and the frequency of occurrence reached a maximum at 6 hr. An evident increase of the pyknotic cells in number was observed at a dose of as little as 1 Gy, and the frequency increased with increases in the dose, reaching over 90% at 15 Gy. Electron microscopy of the irradiated bursa revealed typical apoptotic morphology such as chromatin condensation, nuclear fragmentation, formation of apoptotic bodies and phagocytosis of pyknotic cells. Induction of apoptosis was also confirmed by the appearance of a typical DNA ladder pattern on agarose gel. Thus, the present results demonstrate that the chicken bursal cells are hypersensitive to X-irradiation with regard to induction of apoptosis, and that the apoptotic bursal cells exhibit most of the ultrastructural features known to be typical of apoptosis.

Animals↗
PubMed1996

Cross-sensitivity of X-ray-hypersensitive cells derived from LEC strain rats to DNA-damaging agents.

The cross-sensitivity of X-ray-hypersensitive lung fibroblasts from LEC strain (LEC) rats to other DNA-damaging agents was examined. The LEC cells were 2- to 3-fold more sensitive to bleomycin (BLM) that induces DNA double-strand breaks, and to a cross-linking agent, mitomycin C, than the cells from WKAH strain (WKAH) rats, while they were slightly sensitive to alkylating agents, ethyl nitrosourea and N-methyl-N'-nitro-N-nitrosoguanidine, but not to UV-irradiation. Although no difference was observed in the initial yields of DNA double-strand breaks induced by BLM between LEC and WKAH cells, the repair process of DNA double-strand breaks was significantly slower in LEC cells than in WKAH cells.

Alkylating Agents↗
PubMed1996

Cytolytic activity induced by intramuscular injection of plasmid DNA expressing the nucleocapsid protein of the JHM strain of mouse hepatitis virus into C57BL/6 mice.

We constructed plasmids expressing mRNA7 coding the nucleocapsid (N) protein of JHM strain of MHV (JHMV) under the control of Rous sarcoma virus (RSV) LTR or human elongation factor (EF) 1a promoter, referred to as pRSV-mRNA7 and pEF-mRNA7, respectively. Although only a slight level of cytolysis was observed by the spleen cells from C57BL/6 mice injected intramuscularly with pEF-mRNA7, the spleen cells from the mice administered with pRSV-mRNA7 showed a significant level of cytolytic activities against the cells expressing the viral N protein. The difference in the level of specific cytolysis might have been mainly due to a difference in the expression levels of the N protein in the muscles between the mice injected with pEF-mRNA7 and pRSV-mRNA7, since the specific activity of chloramphenicol acetyltransferase (CAT) in muscles from the mice injected with plasmid DNA expressing CAT gene directed by RSV LTR was significantly higher than that in those administered by the plasmid DNA directed by EF-1a promoter.

Animals↗
PubMed1996

A high frequency of induction of chromosome aberrations in the fibroblasts of LEC strain rats by X-irradiation.

The LEC strain of rats (LEC rats), originally developed as a model for hereditary fulminant hepatitis, is highly sensitive to whole-body X-irradiation when compared to WKAH strain of rats (WKAH rats). The present results showed that frequencies of certain types of chromosome aberrations induced by in vitro X-irradiation in the fibroblasts of LEC rats were higher than those of WKAH rats. In particular, frequencies of chromatid gaps and chromosome exchanges in LEC cells were higher approximately 4- to 5-fold and 6- to 8-fold, respectively, than those of WKAH cells.

Animals↗
PubMed1996

Regional cerebral blood flow measured with 99mTc-HMPAO based on two-dimensional 133Xe study in ischemic brain.

Two-dimensional regional cerebral blood flow (rCBF) was measured using the xenon-133 inhalation method, and used to calibrate the rCBF measured by single photon emission computed tomography (SPECT) in the non-affected middle cerebral artery (MCA) area. The value of the rCBF in the target area could then be measured by SPECT and compared between patients. Technetium-99m-d,l-hexamethyl-propylene-amine-oxime and technetium-99m-diethylenetriaminepenta-acetic acid-human serum albumin D were used to measure rCBF and regional cerebral blood volume (rCBV), respectively, in the ischemic area of 16 patients who underwent surgical revascularization in the chronic stage. No significant increase in rCBF was obtained after the bypass surgery. The delta rCBF and delta CBF/CBV ratio correlated well with the extent of vascularization in the MCA area on postoperative angiograms. Patients with a low CBF/CBV ratio on preoperative SPECT scans tended to show favorable postoperative vascularization and rCBF in the MCA area. Since the angiographic findings and the delta rCBF or delta CBF/CBV were correlated well, this simple and non-invasive method could be used for the analysis of rCBF in a group of patients.

Aged↗
PubMed1996

Early recognition of patients with decreased methotrexate clearance following high-dose methotrexate infusion therapy.

The purpose of this study was to identify the patients with decreased methotrexate (MTX) clearance as early as possible after the start of high-dose methotrexate (HD-MTX) infusion. Fifty-six patients (age: 18 approximately 83 years) received a HD-MTX infusion (dosage: 1.9 approximately 3.8 g/m2) for 6 h. These patients were retrospectively divided into a low-clearance group and a high-clearance group based on the serum MTX concentration at 48 h (1 microM). Six out of the 56 patients showed decreased MTX clearance. The MTX concentrations in the low-clearance group were significantly higher than those in the high-clearance group even in earlier sampling times than at 48 h. The average MTX concentrations were 330 microM at 6 h, 72 microM at 12 h, and 16 microM at 24 h in the low-clearance group, and those in the high-clearance group were 210 microM, 18 microM, and 1.0 microM, respectively. The estimated elimination half-lives (t1/2) at 6 approximately 12 h and 12 approximately 24 h after the start of the infusion were also significantly longer in the low-clearance group (2.8 vs. 1.7 h and 5.0 vs. 2.8 h, respectively). Therefore, we proposed convenient criteria based on the mean + 1 S.D. of the high-clearance group: the concentration > 270 microM at 6 h and > 32 microM at 12 h; the t1/2 value > 2.1 h at 6-12 h. All 6 patients were recognized as belonging to the low-clearance group at an early stage after HD-MTX infusion by using our proposed criteria. These results indicate that patients with decreased MTX clearance could be identified within the first 12 h after the start of HD-MTX infusion. The factors influencing the prolonged elimination of MTX were also investigated. A significant decrease in renal function on day 2 was observed in the low-clearance group. The MTX level at 12 h and the estimated t1/2 values were significantly correlated with BUN, Scr and Clcr on the 2nd day after HD-MTX therapy, suggesting that an alteration in renal function occurs within 12 h of the HD-MTX infusion. The prolonged elimination of MTX could be attributable to this decrease in renal function.

Adult↗
PubMed1995

A method for rapid and complete substitution of the circulating erythrocytes in SCID mice with bovine erythrocytes and use of the substituted mice for bovine hemoprotozoa infections.

We have previously developed an in vivo experimental system for a bovine hemoprotozoan parasite, in which SCID mice were periodically transfused with bovine red blood cells (Bo-RBCs), followed by infection with the parasite. The SCID mice prepared by the original method, however, had both mouse and bovine RBCs in the circulation, and their proportion always fluctuated significantly. In the present study, we aimed to deplete the mouse RBCs circulating in SCID mice and, thereby, to create SCID mice having complete Bo-RBC substitution. An anti-erythropoietin rabbit serum, an anti-mouse RBC rabbit serum and 23 monoclonal anti-mouse RBC rat antibodies were prepared for this purpose. They were examined, after administration into SCID mice, for their ability to decrease hematocrit value and also for any other adverse effect. A monoclonal antibody, clone 2E11, was found to have potent ability to induce clearance of the mouse RBCs in SCID mice without causing toxic effects. SCID mice receiving this antibody together with periodic transfusion of Bo-RBCs had their circulating RBCs completely substituted with Bo-RBCs. Infection of Bo-RBC-SCID mice with bovine hemoprotozoan parasites demonstrated that elimination of the mouse RBCs from Bo-RBC-SCID mice resulted in augmentation of parasite growth.

Anemia↗
PubMed1995

Isolation and characterization of two distinct cDNA clones encoding corn seed cysteine proteinases.

We obtained two cDNA clones encoding corn seed cysteine proteinases (CCP1 and CCP2). Sequence analysis showed that CCP1 consists of 371 amino acid residues, in a prepro-protein form, with two unique short insertions in the mature protein region that are not found in papain or other common CPs. CCP2 consists of 360 amino acid residues with a vacuole sorting signal in the pro-sequence region. An amino acid sequence similarity of 42% was found between the mature protein region of CCP1 and that of CCP2. Although CCP1 is highly homologous to pea 15a CP (72%) and Arabidopsis thaliana RD 19 CP (79%), both of which are known to be induced only when the plant is exposed to a dehydrated environment, it showed very low homologies to other known cysteine proteinases (38-43%). CCP2 showed as much as 87% and 89% identity to rice oryzain gamma and barley aleurain, respectively. We also observed that the CCP1 mRNA is expressed in ripened corn seeds, although its expression reaches a maximum 5 days after the onset of germination. On the other hand, the CCP2 mRNA is expressed only during germination, with maximum expression at the 3-day stage. These results suggest the presence of at least two cysteine proteinases playing differential roles in the corn seeds.

Amino Acid Sequence↗