Biomedical subjects

M Onuma

Publications and source records attributed to M Onuma.

At least 109 records · Page 6Linked to original sources

PubMed1996

Population dynamics of Theileria sergenti in persistently infected cattle and vector ticks analysed by a polymerase chain reaction.

Theileria sergenti Shintoku stock consists of 2 parasite populations bearing 2 allelic forms of p33/32, an immunodominant piroplasm surface protein. Parasite population changes during parasite passages among cattle and tick vectors, and during persistent infection in individual calves were analysed by using allele-specific polymerase chain reaction (PCR). The parasite DNAs were prepared from piroplasms from calves which had been infected with Shintoku stock by inoculation of sporozoite stabilates or parasitized erythrocytes, and from sporozoite stabilates which had been prepared from Shintoku stock-infected ticks. Changes in a dominant parasite population were demonstrated during transmission from calves to vector ticks and from infected ticks to calves. Parasite population changes were also apparent during persistent infection in cattle over several months, and this change is thought to occur under host immune pressure. The results of this study indicate that expression of diverse forms of p33/32 may play a role in parasite persistence within mammalian hosts and its transmission from tick vector.

Animals↗

PubMed1996

Isolation and characterization of gangliosides from Theileria sergenti.

The gangliosides of Theileria sergenti piroplasms were isolated and analyzed by thin-layer chromatography (TLC) and TLC immunostaining test. Four species of gangliosides, designated as G-1, G-2, G-3, and G-4, were separated on TLC. G-1, G-2, G-3, and G-4 ganglioside showed the same mobility as GM3, sialosylparagloboside (SPG), i-active ganglioside, and I-active ganglioside on the TLC plate, respectively. In order to characterize the molecular species of gangliosides from T. sergenti, G-1, G-2, G-3, and G-4 gangliosides were purified and tested by TLC immunostaining test with monoclonal antibodies against gangliosides. G-1 ganglioside had reactivity to anti-GM3 monoclonal antibody. G-2 gave reaction with monoclonal antibody to SPG containing N-glycolylneuraminic acid (NeuGc). G-3 showed reactivity to the anti-i-active ganglioside (NeuGc) monoclonal antibody. G-4 was recognized by the monoclonal antibody which reacts with I-active ganglioside (NeuGc). In addition, sialic acid moiety of the gangliosides from T. sergenti piroplasms was also analyzed. N-acetylneuraminic acid-containing gangliosides were hardly detectable in T. sergenti piroplasms. Gangliosides from T. sergenti (G-1, G-2, G-3, and G-4) carried only NeuGc as their sialic acid moiety. These results suggest that G-1, G-2, G-3, and G-4 gangliosides are GM3 (NeuGc) [NeuGc alpha 2-3Gal beta 1-4Glc beta 1-Cer], SPG (NeuGc) [NeuGc alpha 2-3Gal beta 1-4GlcNAc beta 1-3Gal beta 1-4Glc beta 1-1Cer], i-active ganglioside (NeuGc) [NeuGc alpha 2-3Gal beta 1-4GlcNAc beta 1-3Gal beta 1-4GlcNAc beta 1-3Gal beta 1-4Glc beta 1-1Cer], and I-active ganglioside(NeuGc) [NeuGc alpha 2-3Gal beta 1-4GlcNAc beta 1-3 (Gal alpha 1-3Gal beta 1-4GlcNAc beta 1-6) Gal beta 1-4GlcNAc beta 1-3Gal beta 1-4Glc beta 1-1Cer], respectively.

Anemia↗

PubMed1996

Analysis of neutral glycosphingolipids of Theileria sergenti piroplasms.

Neutral glycosphingolipids (GSLs) were isolated from a lipid extract of Theileria sergenti piroplasms and analyzed by thin-layer chromatography (TLC) and liposome immune lysis assay (LILA); two predominant GSLs, designated as N-1 and N-2 were separated on TLC. N-1 GSL showed the same mobility as lactosylceramide (LacCer) on the TLC plate. On the other hand, the mobility of N-2 GSL on the TLC plate was identical to that of galactosylparagloboside. In order to characterize the molecular species of neutral GSLs from T. sergenti, N-1 and N-2 GSLs were tested by LILA with antibodies against LacCer and galactosylparagloboside, respectively, N-1 GSL had reactivity to anti-LacCer antibody and N-2 reacted with the antibody to galactosylparagloboside. These results suggest that N-1 and N-2 GSLs are LacCer (Gal beta 1-4Glc beta 1-1Cer) and galactosylparagloboside (Gal alpha 1-3Gal beta 1-4GlcNAc beta 1-3Gal beta 1-4Glc beta 1-1Cer), respectively.

Animals↗

PubMed1996

Detection of antibodies against bovine immunodeficiency-like virus in daily cattle in Hokkaido.

Serological survey of bovine immunodeficiency-like virus (BIV) infection was performed in cattle of 3 different farms in Hokkaido, where a relatively high seroprevalence was recorded for bovine leukemia virus (BLV). About a half of 120 cattle tested were seropositive for BLV, while 7.5% of the cattle were seropositive for BIV. Though increased numbers of leukocytes were frequently observed in BLV-seropositive cows, no such changes were observed in BIV-positive but BLV-negative cows. No correlation was demonstrated between BIV- and BLV-seroprevalence of the cattle.

Animals↗

PubMed1996

African swine fever in Zambia: potential financial and production consequences for the commercial sector.

The first officially recorded outbreak of African swine fever (ASF) in Zambia was in Eastern province in 1965. The disease now covers almost the whole province and is endemic in the indigenous breeds. In 1989, an outbreak of ASF occurred on a commercial property in central Zambia for the first time and was eradicated by depopulation. In order to examine the justification of the drastic control measures and the continued ban on the export of pigs and their products, the impact of the outbreak on the affected property as well as the potential consequences on the commercial pig sector in the district was assessed in the present study. The affected property lost 421,238 Zambian Kwacha (ZK) (USf439,965) as a result of the outbreak and control measures. However, the cost to the district could have been at least ZK14,917,500 (US$1,415,323) if the measures had not been effected. Furthermore, not taking such measures would have increased the risk to the entire commercial pig sector along the line of rail in urban centers.

African Swine Fever↗

PubMed1996

Immunomodulative effects of bovine immunodeficiency-like virus (BIV)-infection and mixed infection of BIV and bovine leukemia virus on sheep.

Experimental bovine immunodeficiency-like virus (BIV)-infection and mixed infection of BIV and bovine leukemia virus (BLV) were performed on sheep. BIV proviral DNA and anti-BIV antibodies were persistently detected in all BIV-inoculated sheep. A slight increase in lymphocyte counts was observed in BIV-infected sheep, but the percentages of CD4+ and CD8+ cells in sheep peripheral blood mononuclear cells (PBMCs) were not significantly changed. A transient decrease in lymphocyte blastogenic response to concanavalin. A was observed in two of three BIV-infected sheep at 3-6 months after inoculation. From 6 months after BLV-inoculation to sheep which were previously infected with BIV, the numbers of lymphocytes expressing a tumor-associated antigen (TAA) of bovine leukosis were increased compared to those of a sheep inoculated with BLV alone. The BLV titers in PBMCs and the antibody titers against BLV from sheep infected with both BIV and BLV were higher than those of a sheep inoculated with BLV alone.

Adjuvants, Immunologic↗

PubMed1995

Expression of a 32 kilodalton Theileria sergenti piroplasm surface protein by recombinant baculoviruses.

Previous studies detected a single amino acid substitution (Ala196 to Gly196) between cDNA clones encoding a 32 kDa antigen (p32) of Theileria sergenti (Chitose stock) obtained from a persistently infected calf. In this study, 2 different recombinant baculoviruses (pAc/p32-Ala196 and pAc/p32-Gly196) were constructed for the expression of p32. Molecular masses of the polypeptides produced in Spodoptera frugiperda cells infected with the recombinant baculoviruses were the same as that of authentic p32. pAc/p32-Ala196 produced additional polypeptides, with molecular masses higher than 32 kDa, which resulted from differential N-glycosylation as revealed by endo N-glycosidase treatment. The results indicate that a single amino acid substitution may lead to a conformational change in p32 which affected post-translational modification of recombinant products.

Alanine↗

PubMed1995

Antigenic alteration in major piroplasm surface proteins of Theileria sergenti during infection.

Theileria sergenti piroplasms were purified from different parasitemia peaks of cattle infected with parasitized erythrocytes or sporozoites during persistent infection. Their reactivities with monoclonal antibodies 13F5 and C9, which recognize 23 kDa and 32 kDa piroplasm surface proteins, respectively, were analyzed. Antigenic differences were observed among parasites from different parasitemia peaks during persistent infection when cattle were infected with sporozoites. Results of two-dimensional polyacrylamide gel electrophoresis showed that the 23 and 32 kDa proteins were expressed in all samples tested, regardless of their reactivities with the monoclonal antibodies. In contrast, parasites obtained from cattle inoculated with parasitized erythrocytes showed no antigenic alteration over a 2 month observation period. The results suggest that antigenic alteration of T. sergenti during persistent infection is related to whether the parasites proliferate through extraerythrocytic schizont stage in cattle or sporozoite and other sexual stages in tick vector.

Animals↗

PubMed1995

Immunomodulation of peripheral T cells in chickens infected with Marek's disease virus: involvement in immunosuppression.

Marek's disease virus (MDV) causes T cell immunosuppression in chickens during latent infection. Morphological changes specific to apoptosis were demonstrated in peripheral blood mononuclear cells (PBMC) of MDV-infected chickens at 2-3 weeks post-inoculation (p.i.). Analysis of DNA fragmentation in T cell subsets in the peripheral blood revealed that CD4+ T cells but not CD8+ T cells underwent apoptosis after MDV infection. The proportion of CD4+ T cells, but not that of CD8+ T cells, in the peripheral blood expanded transiently at 16 days p.i., and rapidly decreased 1 week later. The decrease in CD4+ T cells might be mediated by apoptosis, because a rapid reduction in CD4+ T cells was observed when these cells underwent apoptosis. Analysis of the T cell-receptor (TCR) repertoire of the peripheral blood showed that V beta 1 but not V beta 2-alpha beta TCR-bearing cells expanded at 16 days p.i., when the transient expansion of the CD4+ T cell population was observed in these chickens. Flow cytometric profiles also showed that the expression of CD8 was down-regulated after infection with MDV, but there was no difference in the expression level of CD4 molecules between normal and infected chickens. Northern blot analysis indicated that the down-regulation of CD8 occurred at the transcriptional level. These results suggest that both apoptosis of CD4+ T cells and down-regulation of CD8 molecules could contribute to the immunosuppression caused by MDV.

Animals↗

PubMed1995

Development of a new apparatus to observe microcirculation chronically in continuous flow blood pump research.

To observe microcirculation chronically is an important key to the successful evaluation of the continuous flow blood pump. In this study, we succeeded in developing a new apparatus by which microcirculation could be observed chronically without a microscope in a conscious animal. The apparatus utilizes a charge coupled device (CCD). A thin living tissue, such as mesentery, is put directly on a highly integrated CCD and is lit up through the tissue with a light-emitting diode (LED). The vascular nets in the tissue are projected onto the CCD like a contact photograph, which is then sent to a television screen and which can be used to analyze their motion and function. A 0.5-inch CCD having 250,000 pixels was used in this study. The cover glass of the CCD was removed, and a fiber optic plate was fixed onto the surface of the CCD for the tissue to be able to contact with the apparatus surface without clearance. The CCD as well as the LED were molded with epoxy resin for electrical insulation. The apparatus was 35 mm wide and 12 mm high with a micro stand for an LED, which can be easily implanted into an animal. The apparatus was implanted into a rabbit for 12 h. The configuration of arterioles and venules, tens of micrometers in diameter, and their motions in subcutaneous tissue could be observed.

Animals↗

PubMed1995

Gangliosides as a possible receptor on the bovine erythrocytes for Theileria sergenti.

To elucidate whether or not gangliosides on the bovine erythrocytes serve as a receptor for Theileria sergenti merozoites, the reactivities of the T. sergenti piroplasms with gangliosides were studied by the liposome agglutination test. The parasites reacted weakly with I-active ganglioside containing N-acetylneuraminic acid (NeuAc) and strongly with I-active ganglioside containing N-glycolylneuraminic acid (NeuGc). However, none of the other gangliosides expressed on the bovine erythrocytes, such as GM3 (NeuAc), GM3 (NeuGc), sialosylparagloboside (SPG) (NeuAc), SPG (NeuGc), i-active ganglioside (NeuAc), and i-active ganglioside (NeuGc), were recognized. After infection with T. sergenti, furthermore, the content of I-active ganglioside (NeuAc) was less (p < 0.05), and I-active ganglioside (NeuGc) content was much less in the erythrocytes (p < 0.01), though the contents of other NeuAc- and NeuGc-containing gangliosides did not so vary with T. sergenti infection. These results suggest that the parasites recognize the I-active ganglioside as their receptor and bind preferentially to NeuGc-carrying I-active ganglioside rather than to NeuAc-type in the target cell membranes, and that the reduction of the contents of I-active gangliosides (NeuAc and NeuGc) on the erythrocytes was related to T. sergenti infection.

Agglutination Tests↗

PubMed1995

A genetic analysis of mixed population in Theileria sergenti stocks and isolates using allele-specific polymerase chain reaction.

In order to differentiate parasite populations bearing two allelic forms of p33/32, an immunodominant piroplasm surface protein of Theileria sergenti, two sets of oligonucleotide primers were designed to amplify either of the two allele by the polymerase chain reaction (PCR). Each set of the primers differentially amplified either of Ikeda- or Chitose-type p33/32 genes. By using this allele-specific PCR and restriction enzyme digestion of amplified products, parasite populations within field isolates collected from different geographical regions in Japan were analyzed. Both of the allelic forms were detected in 13 samples out of 20 isolates and stocks by PCR. Either of Ikeda or Chitose type of p33/32 allele was detected in the other 7 samples. These results indicated that the majority of T. sergenti-infected calves (11/15) in Japan harbored mixed parasite populations bearing at least two different alleles of p33/32.

Alleles↗

PubMed1995

Effect of administration of serum thymic factor (FTS) in calves and rabbits infected with bovine immunodeficiency-like virus.

The effect of serum thymic factor (FTS) administration in bovine immunodeficiency-like virus (BIV)-infected calves and rabbits was examined. We previously found that some of the macrophage functions were depressed and humoral immune responses against foreign proteins were delayed in BIV-infected calves compared to uninfected calves. After FTS administration, however, no delay of antibody responses against foreign proteins was observed in BIV-infected calves. Though the chemiluminescence (CL) responses of macrophages in BIV-infected calves were significantly depressed (p < 0.05), FTS administration resulted in the recovery of the CL responses in the BIV-infected calves comparable to those in the control calves. Antibody responses against foreign proteins in BIV-infected rabbits were significantly depressed (p < 0.025) as compared with those in uninfected rabbits, though the depression became no significant after FTS administration.

Animals↗

PubMed1995

Characterization of rainbow trout C-polysaccharide binding proteins.

Two proteins were isolated from rainbow trout sera by affinity chromatography using C-polysaccharide-Sepharose 4B column. One was appropriate to the trout C-reactive protein (CRP) that was reported previously (Murai et al. 1990. Dev. Comp. Immunol. 14: 49-58). The other was a newly found protein that had apparent molecular weight of 135,000 on native gradient polyacrylamide gel electrophoresis, and isoelectric points of 5.2-5.8. The N-terminal sequence (twenty amino acids) of the newly found protein was similar to CRPs from other species (e.g. 44% homology with plaice CRP). On electron microscope, the newly found protein was observed as pentagonal symmetry structure.

Amino Acid Sequence↗

PubMed1995

Kinetic analysis of T cells and antibody production in chickens infected with Marek's disease virus.

In chickens inoculated with a Marek's disease (MD) vaccine and subsequently with virulent MD virus (MDV), CD4+ T cell population was drastically decreased following a transient increase at 21 days after hatching (16 days after MDV infection). To elucidate the immune response after the decrease of CD4+ T cell population, the antibody production against sheep red blood cells (SRBC) was examined in these chickens. Chickens challenged with a virulent MDV after MD vaccination produced lower titers, of anti-SRBC antibody than untreated control chickens. Antibody production against SRBC was also lowered in vaccinated chickens or chickens challenged with a virulent MDV.

Animals↗

PubMed1995

[Sleep apnea syndrome in rheumatoid arthritis (RA) patients complicated with cervical and temporomandibular lesions].

All-night polysomnographic studies were performed on ten patients (all female) with rheumatoid arthritis complicated with temporomandibular joint destruction and cervical lesions. The mean age of these subjects was 67.5 yrs, ranging from 48-81 yr. They all had some morphologic abnormalities of cervical spines and/or temporomandibular joints. Sleep study revealed that all of them had sleep apnea; five of them were of obstructive type (obstructive group) while the remaining showed central type of sleep apnea (central group) predominantly. There were no statistically significant differences of the levels of apnea index, mean-nadir SO2 and the lowest SO2 between the obstructive group and the central group. No detectable differences of cephalographic measurements and MRI findings existed between the two groups either. In one patient, nasal-CPAP converted central apnea to normal breathing dramatically. Our observations indicate that the cause of central apnea in RA patients with temporomandibular lesions is collapse of upper airway, inducing inhibitory inputs from the mechanoreceptors in that region.

Aged↗

PubMed1994

Alteration of immune responses of rabbits infected with bovine immunodeficiency-like virus.

Nine 3-month-old rabbits were inoculated with bovine immunodeficiency-like virus (BIV) to study the pathogenesis of BIV and alteration of the immune responses in experimentally infected rabbits. BIV proviral DNA and anti-BIV antibodies were detected from all rabbits inoculated with BIV-infected bovine embryo spleen (BESP) cells. Rabbits inoculated with spleen cells of the BIV-infected rabbit also converted to proviral DNA-positive and BIV-antibody-positive. The blastogenic responses to concanavalin A of peripheral blood mononuclear cells prepared from BIV-infected rabbits were not significantly different from those from uninfected controls at 2 and 4 months post-inoculation (PI). The humoral immune responses against bovine serum albumin (BSA) were depressed in two of four BIV-infected rabbits at 1 to 3 months PI. The antibody responses against sheep red blood cells (SRBCs) were significantly depressed in all BIV-infected rabbits at 2 to 4 months PI. BIV was rescued by cocultivation of spleen cells of infected rabbits with BESP cells. Distinct development of lymphoid follicle was observed in lymph nodes and spleens of uninfected rabbits which received BSA and SRBCs. In contrast, moderate lymphoid cell depletion was observed in BIV-infected rabbits which received the same immunogens.

Animals↗

PubMed1994

Analyses of antigenic and genetic diversities of Theileria sergenti piroplasm surface proteins.

Monoclonal antibodies (MoAbs) against Theileria sergenti Fukushima stock, an intraerythrocytic protozoan parasite of cattle, were produced. The MoAbs reacted with 32 kDa or 23 kDa piroplasm surface protein (p32 or p23) in Western blot analysis. Using a panel of the MoAbs, antigenic analysis of the stocks and field isolates distributed in Japan was carried out. The results revealed antigenic diversity of T. sergenti isolates, but diversity did not appear to be correlated with the geographical region of the isolates. N-terminal amino acids sequences analysis revealed substitutions of a few amino acids between the p23 of two T. sergenti stocks. The sequences couldn't be found in amino acid sequence of the p32 deduced from cDNA, which indicated that the p23 is not a proteolytic product of the p32. Genetic diversity of T. sergenti isolates was also observed by Southern blot analysis using a cDNA of the p32 as a probe.

Amino Acid Sequence↗