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Biomedical subjects

M Pollard

Publications and source records attributed to M Pollard.

At least 127 records · Page 7Linked to original sources

In vivo host immune to a tumor-specific transplantation antigen induced by Rous sarcoma virus.

We examined the host immune response to a tumor-specific transplantation antigen (TSTA) induced by Rous sarcoma virus (RSV) In vivo. In contrast to previous in vitro studies, the present investigation demonstrated in vivo host immunity of the TSTA 10-55 days after tumor inoculation. Immunity to the TSTA appeared specific, since the homologous RSV tumor was rejected. whereas the heterologous tumor grew progressively. No generalized suppression of cell-mediated or hymoral immunity was shown, because tumor-bearing hosts retained the ability to reject heterologous tumor cells and mounted a normal plaque response to sheep red blood cells. Although alpha-globulin levels were elevated, they did not appear to affect the host's immunity to the growing tumor or to heterologous antigens. Assoicated with the progressively growing tumor was the appearance in the serum of a fetal antigen with characteristics of an alpha-2 acute phase protein.

Alpha-Globulins↗

Allogeneic bone marrow chimerism in germ-free mice. IV. Therapy of "Hodgkin's-like" reticulum cell sarcoma in SJL mice.

"Hodgkin's-like reticulum cell sarcoma develops spontaneously in most SJL mice. Germ-free and conventional SJL mice bearing advanced reticulum cell sarcoma were treated with X-irradiation and transplantation of bone marrow from SJL or C3H/He donors. The 120-day survival rate of germ-free mice receiving allogeneic bone marrow (70%) exceeded that of all control groups; more importantly, germ-free mice that survived more than 4 months after treatment with allogeneic cells had no evidence of neoplastic lesions when killed. The germ-free environment effectively prevented graft-versus-host disease that was lethal to conventional mice. The results of these experiments offer additional evidence that bone marrow transplantation can be used as a therapeutic tool for spontaneous murine neoplasms.

Animals↗

Bacterial decontamination and antileukemic therapy of AKR mice.

Four nonabsorbable antibiotics (streptomycin, neomycin, bacitracin, and amphotericin B) and a germicidal dip solution (Zephiran chloride/water) were used to eliminate all the detectable bacteria from conventional AKR mice. Control mice were not decontaminated and were used as such. When antibiotic-decontaminated and control mice developed clinical manifestations of spontaneous lymphatic leukemia, each was treated for the disease with an antitumor drug (cyclophosphamide [CP]) at weekly intervals. With the decontamination procedure, mice of each of the two groups became bacteria-free after 16 weeks of continuous oral administration of the antibiotics and two separate germicidal dippings. All decontaminated mice remained free of bacteria throughout the experiment. The bacterial flora of the control mice remained unaltered. With CP therapy, the mean survival time of the female decontaminated mice was 65 days, whereas that of male mice was 218 days. The average survival time of the CP-treated control leukemic mice was 51 days. Untreated decontaminated or control mice usually died of leukemia within 7 days after the onset of symptoms of leukemia. Although CP therapy was not curative, it did prolong the life expectancy of the decontaminated mice significantly.

Amphotericin B↗

Ultrastructural cytology of prostate carcinoma cells from Wistar rats.

Cells from spontaneous adenocarcinomas of the prostate (Pollard, M.: J. Natl. Cancer Inst. 51: 1235, 1973) in aged Lobund Wistar rats were examined by electron microscopy. Cytologic structures of the rat prostate tumor cells resembled analogous structures from human prostate tumor cells. These findings support the prospect that the rat prostate tumor will provide a model system of prostate cancer in man.

Adenocarcinoma↗

Inactivation of viruses and bacteria by ozone, with and without sonication.

Selected organisms with public health significance were placed in a reaction chamber for treatment by ozonation, by ozonation and sonication, by sonication, or by sonication during oxygenation. Vesicular stomatitis virus, encephalomyocarditis virus, GDVII virus, Staphylococcus aureus, Pseudomonas fluorescens, Salmonella typhimurium, enteropathogenic Escherichia coli, Vibrio cholerae, and Shigella flexneri were inactivated by treatment with ozone. When microorganisms were suspended in phosphate-buffered saline, they were inactivated rapidly by treatment with ozone. However, microorganisms suspended in secondary effluent from a wastewater treatment plant required longer contact times with ozone for complete inactivation. Simultaneous treatments by ozonation and sonication reduced the contact time for complete inactivation of microorganisms in secondary effluent. Treatment by sonication alone or sonication and oxygenation did not inactivate microorganisms. Therefore, the simultaneous treatment of microorganisms in secondary effluent with ozone and sonication resulted in a synergistic effect.

Animals↗

Effects of cholestyramine on 1,2-dimethylhydrazine-induced enteric carcinoma in germfree rats.

Oral administration of 1,2-dimethylhydrazine (DMH) induced intestinal neoplasms in germfree rats. A supplement of 2% cholestyramine resin in the diet increased the frequency of DMH-induced intestinal tumors and accelerated malignant transformation. Bile acids in the cecal content were determined with and without cholestyramine in order to obtain a correlation between the bile acid metabolism and the enteric carcinogenesis.

Adenocarcinoma↗

Transplantable metastasizing prostate adenocarcinomas in rats.

Three spontaneous prostate adenocarcinomas from aged, randombred, germfree Lobund Wistar rats were transplanted, without change, through several series of conventional Lobund Wistar rats. One tumor type differed histologically from the other two tumor types. Rats with subcutaneously transplanted tumors developed metastatic tumors in the lymph nodes and lungs. No microbial agent was detected in the tumor cells.

Adenocarcinoma↗