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Biomedical subjects

A Iwata

Publications and source records attributed to A Iwata.

116 records · Page 7Linked to original sources
PubMed1971

Effect of phleomycin on polyoma virus synthesis in mouse embryo cells.

The addition of phleomycin (25 mug) to primary mouse embryo cells infected with polyoma virus was found to cause 96% inhibition of the synthesis of infectious virus. When ribonucleic acid and protein synthesis was investigated in these cells by use of isotope incorporation, it was found that neither was inhibited drastically. Immunofluorescent staining studies with the use of antibody directed to the viral structural proteins showed that proteins were synthesized in the presence of the antibiotic. However, when deoxyribonucleic acid (DNA) synthesis was investigated, it was found that DNA synthesis in uninfected cells was completely inhibited within the initial 10 hr of phleomycin addition, whereas DNA synthesis in infected cells proceeded at a reduced rate. Selective DNA extraction (Hirt method) of phleomycin-treated infected cells demonstrated that synthesized viral DNA was salt-extractable, similar to that in infected control cells lacking phleomycin. This extracted DNA was further fractionated by ethidium bromide-cesium chloride density gradient equilibrium centrifugation. The phleomycin-treated preparations revealed twice as much component II (circular nicked and linear) as component I (supercoiled) DNA, whereas the DNA from normally infected control cells showed the reverse picture. It was also demonstrated that viral particles synthesized in the presence of phleomycin did not contain component I DNA. This packaged DNA was found to consist of fragments of both the host and viral types. Cells that were prelabeled with (3)H-thymidine and then treated with phleomycin demonstrated host DNA degradation. However, fragments formed from prelabeled host DNA were not encapsidated into viral particles.

Anti-Bacterial Agents↗
PubMedDate not supplied

Serum 2',5'-oligoadenylate synthetase activity during interferon treatment of chronic hepatitis B.

We measured 2',5'-oligoadenylate synthetase activities in serum and peripheral blood mononuclear cells from 10 patients with chronic hepatitis B who were being treated with interferon so as to determine whether 2',5'-oligoadenylate synthetase activity in serum reflected 2',5'-oligoadenylate synthetase activity in peripheral blood mononuclear cells, and whether it could be used to monitor interferon treatment. Pretreatment values of 2',5'-oligoadenylate synthetase activity in patients' serum and peripheral blood mononuclear cells were not statistically different from values from control subjects. When interferon was administered, serum levels of 2',5'-oligoadenylate synthetase began to rise within 3 hr, reached peak values at 12 hr and then declined. The levels of 2',5'-oligoadenylate synthetase activity both in serum and peripheral blood mononuclear cells increased substantially during interferon treatment, ranging 2- to 50-fold greater than initial levels. The levels of 2',5'-oligoadenylate synthetase in serum correlated closely with levels in peripheral blood mononuclear cells. In addition, when the levels of 2',5'-oligoadenylate synthetase rose during interferon administration, serum hepatitis B virus DNA polymerase values fell, and, in some cases, DNA polymerase rose again when 2',5'-oligoadenylate synthetase fell after discontinuation of interferon. These findings suggest that 2',5'-oligoadenylate synthetase activity in serum accurately reflects the antiviral effect of interferon and could be used to monitor interferon treatment.

2',5'-Oligoadenylate Synthetase↗
PubMedDate not supplied

Biological and immunogenic properties of rabies virus glycoprotein expressed by canine herpesvirus vector.

In order to evaluate whether canine herpesvirus (CHV) could be used as a live vector for the expression of heterologous immunogenes, we constructed a recombinant canine herpesvirus (CHV) expressing glycoprotein (G protein) of rabies virus (RV). The gene of G protein was inserted within the thymidine kinase gene of CHV YP11mu strain under the control of the human cytomegalovirus immediate early promoter. The G protein expressed by the recombinant CHV was processed and transported to the cell surface as in RV infected cells, and showed the same biological activities such as low pH dependent cell fusion and hemadsorption. The antigenic authenticity of the recombinant G protein was confirmed by a panel of monoclonal antibodies specific for G protein. Dogs inoculated intransally with the recombinant CHV produced higher titres of virus neutralizing antibodies against RV than those inoculated with a commercial, inactivated rabies vaccine. These results suggest that the CHV recombinant expressing G protein can be used as a vaccine to control canine rabies and that CHV may be useful as a vector to develop live recombinant against other infectious diseases in dogs.

Animals↗
PubMedDate not supplied

Osteosarcoma as a second malignancy after treatment for neuroblastoma.

A 4-month old girl was diagnosed as having stage IV neuroblastoma of the right adrenal gland. Preoperative chemotherapy was given, followed by local surgical excision. Postoperatively, irradiation of the tumor bed and adjuvant chemotherapy was given for 11 months. Nine years after cessation of chemotherapy, the patient developed left hip-joint pain. Biopsy of the ischium showed chondroblastic osteosarcoma. Limb salvage surgery was performed after preoperative chemotherapy. Postoperatively, adjuvant chemotherapy was given for 14 months. Twenty-two months after treatment for the secondary osteosarcoma, the patient has been remained in disease-free condition without any evidence of relapse. A second osteosarcoma occurring outside the radiation field after treatment for neuroblastoma is quite rare. This unusual case emphasized the need for close monitoring for development of second malignant neoplasms in survivors of neuroblastoma even in the absence of a known predisposing factor, such as radiation therapy.

Combined Modality Therapy↗
PubMedDate not supplied

Spiral hyphae of Candida albicans formed in anaerobic culture.

Candida albicans from a patient with dental caries grew on minimal medium consisting of agar supplemented with magnesium chloride and sodium phosphate. Hyphal growth was observed when the yeast was cultured between 26 degrees C and 28 degrees C under aerobic conditions, and typical chlamydospores were formed. However, when the yeast was cultured at the same temperature under anaerobic conditions, curly hyphae developed on the surface of the medium, but no chlamydospores were formed. This phenomenon was also observed if the culture was started under aerobic conditions but was continued under anaerobic conditions.

Anaerobiosis↗