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Biomedical subjects

T Mikami

Publications and source records attributed to T Mikami.

At least 613 records · Page 34Linked to original sources
PubMed1985

Characterization of reference strains of Newcastle disease virus (NDV) and NDV-like isolates by monoclonal antibodies to HN subunits.

The hemagglutinin-neuraminidase (HN) subunits of NDV and NDV-like isolates were analyzed antigenically by monoclonal antibodies to the HN of Miyadera and Taka viruses. In immuno-double-diffusion (IDD) tests, all NDVs examined gave clear lines of precipitation with some of the potent monoclonal antibodies, but it was difficult to determine with certainty the immunological properties of HN subunits due to a rare disagreement with the results obtained in other immunological tests. Monoclonal antibodies used in the tests were found to show different immunological reactivities with the viruses. Monoclonal antibodies belonging to the 1st group (1/29) inhibited the hemagglutinating (HA) activity of all strains but not the neuraminidase (NA) activity. The second monoclonal antibody (5/205) inhibited both the HA and NA activities of the restrictive NDV strains, indicating antigenic changes in HN molecules. However, the inhibitory activity of this monoclone to neuraminidase appeared to be greatly diminished when neuraminyl lactose was used as substrate. Although the 3rd type of monoclonal antibody (5/220) showed HI activity against several strains, this antibody did not inhibit NA activity of any viruses. The remaining monoclone to the HN of Taka virus inhibited the HA activity of all reference strains of NDV and many NDV-like isolates but did not affect NA activity. Two inhibitory activities of four monoclonal antibodies against different viruses, HI and hemolysis-inhibition, were not always consistent with inhibition of virus growth. HI and NI tests with the above four monoclonal antibodies showed that the strains tested fell into five antigenic groups according to their reaction patterns with mouse hybridoma antibodies.

Animals↗
PubMed1985

Existence of cytotoxic activity against BLV-transformed cells in lymphocytes from normal cattle and sheep.

Peripheral blood lymphocytes (PBL) from normal cattle and sheep were tested for their cytotoxic activity against several target cells using a 20-hour 51Cr release assay. The following characteristics of the effector cells were observed; 1) PBL from animals showed cytotoxic activity against two sheep cell lines (FLK and SF-28) that were transformed with bovine leukemia virus. However, normal sheep and bovine cells and Molony leukemia virus-induced mouse lymphoma cell line (YAC-1) were not killed by these cells. 2) A time course study showed that the activity was first observed at 4 to 8 hours and reached a maximum at 20 to 30 hours after incubation. 3) Cytotoxic activity was observed in both adherent and nonadherent cell fractions when PBL were passed through a nylon-wool column. This indicated that the effector cells showed some degree of adherence. 4) Treatment of PBL with carrageenan did not change the cytotoxic activity against target cells, indicating that phagocytic capability is not perhaps necessary for cytotoxicity to take place. These results indicate that the effector cells participating in the cytotoxic reaction resembled natural killer cells or natural cytotoxic cells which are present in murine and human systems. However, analysis of the cell surface markers of the effector cells is yet to be done in future studies.

Animals↗
PubMed1985

Characterization of extracellular substance of Vibrio anguillarum toxic for rainbow trout and mice.

An extracellular toxic substance was separated from the cell-free culture filtrate of Vibrio anguillarum (strain NCMB571). Two fractions (GI and GII + III) obtained by Sephadex G-200 chromatography following DEAE-cellulose chromatography were lethal to rainbow trout and mice. Material separated from the GI fraction by Sepharose 4B affinity chromatography (GI-A fraction) was lethal to these animals. By sodium dodecylsulfate polyacrylamide gel electrophoresis, the GI and GI-A fractions were found to be composed of components with molecular weights of 44K and 34K, and 44K, respectively. The 44K protein band was associated with carbohydrate. Peripheral vascular disorder was observed in fish and mice that died after inoculation with GI or GI-A fraction. The toxic substance was sensitive to potassium periodate but was resistant to trypsin and acetone. Heat inactivation of the toxic substance was almost complete at 100 C for 20 min and complete at 121 C for 20 min. The toxic activity was not associated with hemolytic or proteolytic activity. Homologous antitoxin completely neutralized the toxic activity.

Animals↗
PubMed1985

Effects of some non-steroidal anti-inflammatory drugs and other agents on cyclooxygenase and lipoxygenase activities in some enzyme preparations.

The inhibiting influences of some non-steroidal anti-inflammatory drugs (NSAIDs) and other agents on cyclooxygenase (CO) and lipoxygenase (LO) activities in some enzyme preparations were investigated. Washed rat platelets (CO and 12-LO), rat polymorphonuclear leukocytes (PMNs, CO and 5-LO), rat renal medulla homogenate (CO), and purified soybean LO (15-LO) were used as enzyme preparations. The IC50 values of drugs on the enzyme activities were determined in each preparation. In addition, the inhibitory activities of the drugs on the generation of chemiluminescence from PMNs stimulated by phorbol myristate acetate were tested. NSAIDs (indomethacin, ketoprofen and phenylbutazone) showed a selective inhibition of CO in each preparation, but benoxaprofen inhibited both enzymes, especially in PMNs. BW755C, 1-phenyl-3-pyrazolidone (phenidone), toluene-3,4-dithiol (dithiol), 6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline (ethoxyquin) and acetone phenylhydrazone (APH) inhibited both enzyme activities. Nordihydroguaiaretic acid (NDGA) showed a relatively selective inhibition of LO in all the preparations used. APH inhibited soybean 15-LO markedly compared with the other enzymes tested. Ethoxyquin inhibited COs more markedly than LOs, and with regard to LO inhibition, it inhibited 5-LO in PMNs markedly. BW755C, phenidone, ethoxyquin, NDGA, APH and dithiol, which strongly inhibited 5-LO, showed an inhibitory activity on the generation of chemiluminescence from PMNs activated with phorbol ester.

Animals↗
PubMed1985

[Teratogenic potentially of single dose of thalidomide in JW-NIBS rabbits].

A single dose (500 mg/kg) of thalidomide was administered orally to pregnant JW-NIBS rabbits in various stages of organogenesis. Head anomalies in fetuses (anencephaly, holoprosencephaly and hydrocephaly) were induced at a high frequency by the maternal administration of thalidomide on day 7, and also in a few fetuses on day 8. These fetuses included those with an abnormal skull such as hypoplasia of cerebral and facial skull. Microphthalmia in fetuses was observed with a single administration from day 7 to 12 of gestation. Contracture of forearms and club foot in fetuses resulted from the maternal administration of thalidomide on day 8 or 9 of gestation, respectively. With a single administration on day 8 or 9 of gestation, kinky tail in fetuses resulted, and brachyury was observed with a high frequency from day 8 to 11 of gestation. Skeletal anomalies such as fusion or displacement of coccygeal vertebral bodies were observed at a high frequency with a single treatment from day 8 to 10 of gestation. Among the internal anomalies observed was abnormal lobation of the lung, resulting from a single treatment from day 6 to 15 of gestation (except for day 13), and abnormal lobation of the liver, induced from day 7 to 10. The cardiovascular anomalies were induced at a high frequency with a single treatment from day 7 to 9 of gestation. In the present experiment, the critical period for each anomaly produced by thalidomide in JW-NIBS rabbits was determined.

Abnormalities, Drug-Induced↗
PubMed1985

Comparison of the major histocompatibility antigen on Marek's disease-derived cell lines detected by membrane fluorescent antibody, cytotoxicity, and lymphoagglutination tests.

The reactivity of 13 antisera specific for the major histocompatibility antigen (MHA) of the B complex against cells in 6 cell lines (MDCC-JP1, JP2, HP1, HP2, RP1, and MSB1), derived from Marek's disease (MD) lymphoma, was compared by using membrane fluorescent antibody, cytotoxicity, and lymphoagglutination tests. The membrane fluorescent antibody test was found to be the most sensitive method for detecting the MHA of the B complex on the MD cell lines. After absorption of these antisera with the homologous erythrocytes, the reactivities of the absorbed sera to the homologous erythrocytes and the MD line cells were reduced or lost altogether. However, after absorbing the antisera reactive for MD cell lines with the respective cell line, the reactivities of the absorbed sera to the line cells were not detected at all when examined by the above tests. However, the reactivities of these absorbed sera to the homologous erythrocytes could still be observed when examined by a hemagglutination test. These results indicate that the antisera contain at least two kinds of antibody (against Class I and Class IV antigens), and the three different tests used here are detecting the Class I antigens of MHA on the MD line cells.

Agglutination Tests↗
PubMed1985

Topographical analysis of tumor-associated antigens on bovine leukemia virus-induced bovine lymphosarcoma.

Tumor-associated antigens (TAAs) expressed on tumor cells from cattle with enzootic bovine leukosis were divided into three groups by using 13 monoclonal antibodies: common TAA; partially common TAA; and individually distinct TAA. TAA was extracted from tumor cells and purified by ion exchange chromatography on diethylaminoethyl-cellulose and isoelectric focusing. The common TAA, which was detected on all tumors tested, was eluted with 0.6 M KCl in ion exchange chromatography on diethylaminoethyl-cellulose, and the isoelectric point of the antigen was 6.8. The partially common TAA, which was detected on some (but not all) of the tumors tested, was eluted with 0.4 to 0.8 M KCl, and the isoelectric points of the antigen were 5.3, 5.8, and 6.4. The individually distinct TAA was present in the fractions eluted with 0.4 to 0.8 M KCl, and the isoelectric point of the antigen was 5.5. Results of competitive binding assay and Western blot analysis showed that the common TAA was a polypeptide with a molecular weight of 74,000; that it has at least two independent antigenic regions; that the partially common and individually distinct TAAs were a polypeptide with a molecular weight of 64,000; and that the antigenic determinants on the common TAA, partially common TAA, and individually distinct TAA existed independently from each other.

Animals↗
PubMed1985

Tumor-associated antigens on bovine leukemia virus-induced bovine lymphosarcoma identified by monoclonal antibodies.

Thirteen monoclonal antibodies directed against tumor cells from cattle from enzootic bovine leukosis (EBL) were obtained. They reacted with tumor cells but not with normal bovine cells or bovine leukemia virus antigens. According to the reactivities of these antibodies with 19 individual tumors, the 13 monoclonal antibodies can be divided into three groups. Antibodies of the first group reacted with all the EBLs tested; those of the second group reacted with several, but not all, of the EBLs tested; and those of the third group reacted only with homologous tumor cells. Therefore, tumor-associated antigen (TAA) on the EBL tumor may possess common TAA, partially common TAA, and individually distinct TAA. The TAAs were solubilized from the tumor cells by treatment with 0.2% sodium deoxycholate and partially purified by diethylaminoethyl-cellulose column chromatography. Eleven of the 13 monoclonal antibodies reacted with this soluble TAA. The monoclonal antibodies belonging to the first group inhibited in vitro the growth of the bovine lymphoid cell line derived from the EBL tumor.

Adsorption↗
PubMed1984

Mechanisms for development of functional tricuspid regurgitation determined by pulsed Doppler and two-dimensional echocardiography.

Mechanisms for the development of functional tricuspid regurgitation (TR) were studied in 41 patients by ultrasound. The severity of TR was classified into 4 grades according to the extent of the regurgitant signal by pulsed Doppler echocardiography (echo). No TR signal was detected in 11 patients; the grade of TR was 1+ in 9 patients, 2+ in 10, 3+ in 8 and 4+ in 9. Using 2-dimensional echo, the tricuspid anular area was estimated from a horizontal and a sagittal diameter of the anulus, and systolic configurations of the tricuspid valve was observed. The tricuspid anular area corrected for body surface area increased with the grade of TR. Anterior displacement of the tips of the tricuspid leaflets was seen in 10 patients with TR of 2+ or greater severity, and its frequency also increased with the grade of TR. Loss of coaptation was seen in 3 patients with 4+ TR and malaligned coaptation was seen in 4 patients with TR of variable degrees. Tricuspid anular dilatation and anterior displacement of the tricuspid leaflet tips causes a separation between the leaflet tips and appears to be the main mechanisms for the development of functional TR. Malaligned coaptation also plays a role in the development of functional TR.

Echocardiography↗
PubMed1984

Monoclonal antibodies against BLV-transformed sheep cells. Brief report.

Hybrid cell lines were prepared by the fusion of BALB/c myeloma, P3X63Ag 8.653 cells with the spleen cells of BALB/c mice that were immunized with SF-28 cells, sheep fibroblasts transformed with BLV in vitro. Five clones of hybrid progeny produced cytotoxic IgG1 antibodies against SF-28 cells. The tested monoclonal antibodies showed cytotoxic activity against 4 out of 6 BLV-transformed sheep fibroblasts as well as SF-28 cells but failed to react with other cells, including BLV-producing FLK cells, bovine lymphosarcomas and normal sheep cells. These monoclonal antibodies showed suppressive effect on colony formation of SF-28 cells in soft agar culture.

Animals↗