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Biomedical subjects

M Onuma

Publications and source records attributed to M Onuma.

At least 271 records · Page 15Linked to original sources
PubMed1979

Further study on the three-dimensional structure of the core of Marek's disease virus and herpesvirus of turkey.

Three-dimensional structures of the core of Marek's disease virus and herpesvirus of turkey were examined by the tilting apparatus of an electron microscope. Various types of the core found in the infected cells were considered to represent developmental stages of the viruses. The basic structure of the core consisted of a toroid surrounding a cylindrical mass, which was clearly demonstrated by tilting the core in two directions. A cylindrical mass spooled by more than two toroids, which seemed to constitute a spiral band of 10 to 20 nm, was demonstrated. The maturation process of the cores of the viruses was also discussed.

Animals↗
PubMed1978

Induction of C-type virus in cell lines derived from calf form bovine lymphosarcoma.

For attempt to detect an etiological agent, cultures from bovine lymphosarcoma cases (adult form (ALS), calf form (CLS), and thymic form (TLS) were maintained in vitro for over a 18 month period. In two cultures from ALS, bovine leukemia virus (BLV) antigen was constantly detected. On the other hand, BLV antigen remained negative in cultures from two CLS and one TLS cases up to 40 passages. The RNA dependent DNA polymerase activities in these cultures were also negative. Treatment of a culture from CLS (3178) originated from liver tumor with 5'-iodo-2'-deoxyuridine (IdU) and dexamethasone (DXM) resulted in production of an agent serologically and morphologically similar to BLV and in alteration of cell morphology. No virus was detected in culture from TLS after treatment with IdU and DXM.

Animals↗
PubMed1978

Intranasal tumor of the ethmoid olfactory mucosa in sheep.

Intranasal tumors (papillary adenomas or adenocarcinomas) of the ethmoid olfactory mucosa of sheep were investigated by light and electron microscopy. The fine structure of the tumor cells was characterized by the presence of numerous secretory granules. Viral particles, which were morphologically similar to a visna-maedi virus, were detected in all tumor tissues and in 3 of 4 cultures examined. The particles (about 97 nm) had an eccentrically located electron-dense core and numerous spikes on their surfaces. The RNA-dependent DNA polymerase activities in the tumor cells or the cultured cell from the tumor were greater than those in the normal intranasal tissues or the cultured cells from the choroid plexus. Viral particles similar to herpesvirus were also detected in 1 culture.

Adenocarcinoma↗
PubMed1978

Tumor-associated antigen and cell surface marker in cells of bovine lymphosarcoma.

The detection of tumor-associated antigen and B cell surface marker was attempted in lymphoid cells of peripheral blood (PBL) and lymph nodes obtained from cattle with lymphosarcoma, cattle infected with bovine leukosis virus (BLV), and clinically normal cattle. As a result, specific tumor-associated antigen was found in PBL and lymphoid tumor cells from cattle with the adult form of lymphosarcoma (ALS) using anti-ALS serum. The antigen was also detected in PBL of BLV-infected cattle. A weak reaction for the antigen was found in 2 of 5 cases of calf form. No significant reaction for the tumor-associated antigen of neoplastic lymphoid cells from ALS was found in the thymic and skin forms. The percentage of B cells in PBL and lymph nodes from ALS was higher than that in normal cattle. However, a loss of B cell surface marker was suggested in some ALS cases. A good relation was obtained between an increased B cell percentage and an appearance of the tumor-associated antigen in PBL of BLV-infected cattle. In lymphoid cells of PBL and lymph nodes from sporadic cases, the percentage of B cells was lower than that observed in normal cattle.

Animals↗
PubMed1978

Studies on cell lines derived from calf, thymic and skin forms of bovine lymphosarcoma.

The etiology of sporadic bovine leukosis (SBL) is not known. Long-term monolayer cultures were made from calf (CLS), thymic (TLS) and skin (SLS) forms, and serological tests, electron microscopic observations and reverse transcriptase assays were employed for the detection of an etiological agent. Bovine leukosis virus (BLV) antigen and reverse transcriptase activities remained negative in cultures from SBL cases. Treatment of a culture from CLS 3178 with 5'-iodo-2'-deoxyuridine and dexamethasone resulted in production of BLV which may have been acquired from the BLV-infected dam of CLS 3178, and in an alteration of cell morphology. Focus formation in monolayer cultures and colony formation in soft agar cultures were observed in this treated cell line. Human fetal lung fibroblast cells cocultivated with the cultures from SBL resulted in rapid proliferation of cells with an increased focus formation.

Animals↗
PubMed1977

Location of antigens associated with bovine leukemia virus.

Antigens associated with bovine leukemia virus (BLV) infection (gp 44/55 and p23) were identified by neutralization and immunofluorescent antibody (FA) tests. Only serums containing antibody to gp 45/55 neutralized the virus; antibody to p23 did not. These results indicate that gp 44/55 may be located in the virus envelope. In indirect FA tests, both a cytoplasmic fluorescence and a membrane fluorscence were detected in BLV-infected cells. The serum used in the FA test was then absorbed with either p23 or gp 45/55. The results of these absorption tests indicate that the membrane fluorescence maybe associated with gp 45/55 and the cytoplasmic fluorescence may be associated with p23.

Absorption↗
PubMed1977

Inhibition of bovine leukemia virus release by antiviral antibodies.

Peripheral blood lymphocytes from bovine leukemia virus (BLV) infected cattle were grown in vitro with serums from BLV-infected and uninfected cattle, sheep and rabbits. Only serums from infected animals which had antibody to gp 45/55, the major glycoprotein antigen, inhibited the release of virus from the cells. Although viral antigens could be detected in the cells themselves, none were detected in the supernatants of cultures grown with these serums. Normal serums and serums with antibody only to p23, the internal BLV antigen, did not inhibit virus release. To identify the factor responsible for virus release inhibition, 2 inhibitory serums were absorbed with either gp 44/55, p23 or tissue culture cells from BLV-infected and uninfected cells lines. The results indicated that antibody to gp 45/55 is the factor responsible for virus release inhibition.

Absorption↗
PubMed1977

Tumor-associated antigen in bovine and ovine lymphosarcoma.

Specific tumor-associated antigens were found on the membrane and in the cytoplasm of lymph node cells and peripheral blood lymphocytes (PBL) from cattle and sheep with lymphosarcoma by immunofluorescence tests. Materials from 15 cattle with the adult form of lymphosarcoma were examined. Cytoplasmic antigen was detected in fixed tumor cells from all 15 cases and in PBL from 9 cases tested. Membrane antigen was detected in living cells from 10 of the cases tested. In 3 calf-type cases, cytoplasmic antigen was found in a few (1 to 3%) of the tumor cells, while 1% of the cells from 2 thymic cases had cytoplasmic tumor antigen. In 15 cattle infected with bovine leukemia virus (BLV) but with no evidence of tumor, PBL from 3 cattle had the tumor-associated antigen in the cytoplasm. Negative results were obtained with similar tests done with 9 normal cattle that had no detectable BLV or BLV antibody. Cells from tumors induced with BLV in 5 sheep also had cytoplasmic antigen and membrane tumor-associated antigen. Tumor-associated antigen was found in PBL from 1 or 7 BLV-infected sheep with no clinical evidence of tumor. Similar tests were negative on 4 normal sheep.

Animals↗
PubMed1977

Fetal infection with bovine leukemia virus in sheep.

Several sheep fetuses were thymectomized, and their tails were removed at 58 to 65 days of gestation for tissue culture. Bovine leukemia virus (BLV) antigens were detected in serial culture of tissues from fetuses whose dams and sires were both BLV positive. However, no BLV antigens were detected in serial cultures of tissues from fetuses whose dams were negative but whose sire was positive. Precolostral serums from 3 of 16 neonatal lambs, whose sire and dams were both BLV positive, were BLV antibody positive. Thus, BLV may be vertically transmitted from a positive dam to her lamb via the placenta and/or germinal cells but not from sire to lamb.

Animals↗
PubMed1976

Effect of pasteurization and heat treatment on bovine leukemia virus.

Four sheep inoculated with mixtures of bovine leukemia virus (BLV) and milk that was treated by a simulated high-temperature short-time pasteurization procedure did not become infected with BLV or develop tumor. Four sheep inoculated with unpasteurized BLV-mil mixtures became infected with BLV and 3 died with tumor at 15, 21, and 27 months, respectively, after inoculation. Fluid from a BLV-infected cell culture was heated to 56, 60, 65, and 73 C for 1/2 minute and 1 minute (in separate trials) and transferred to noninfected cells. Culture fluid heated to 60 C and higher did not infect the cells.

Animals↗