Search PubMed⌕ Search

Biomedical subjects

A Rios

Publications and source records attributed to A Rios.

At least 109 records · Page 6Linked to original sources
PubMed1982

Determinations of gray cell coefficient in the dorsal lateral geniculate nucleus of the mouse.

This study is an analysis of the gray cell coefficient carried out in different regions of the dorsal lateral geniculate Nucleus (dLGN) of the mouse. We have analysed the contribution three different sized neuron types to the coefficient. Only about 6% of the total volume of the dLGN is occupied by nerve cell bodies, and the neurons that account for most of this 6% are medium sized (the largest diameter being between 8 and 11 microns.) The smallest neurons are mainly located in the more peripheral region of the nucleus.

Animals↗
PubMed1981

Organ distributions and clearance studies of 99mtechnetium-labeled Corynebacterium parvum in patients with leukemia.

The clearance, metabolism and localization of Corynebacterium parvum (C. parvum) labeled with 99mtechnetium (99mTc) given intravenously was studied in various leukemia patients to develop the method and to evaluate reticuloendothelial systems (RES) function. A computer program was utilized to characterize the clearance. C. parvum 0.05 mg was labeled aseptically with 10 mCi of 99mTc with a reducing agent. It was injected intravenously over 5 s and clearance was characterized over the next 60 min. The low dose of C. parvum did not cause any symptoms. The blood or plasma clearance time (t 1/2) was in the range of 0.65 to 1.96 min, in eight patients. By whole body imaging, the distribution of C. parvum was found mainly in the liver, and to a much lesser extent in the spleen, lungs, and bone marrow. Nonparticulate 99mTc (which was not sedimented by centrifugation of blood samples at 3000 rpm for 30 min) appeared rapidly in the blood after i.v. injection accounting for more than half of the radioactivity in a few minutes. In vitro incubation of 99mTc labeled C. parvum with saline, whole blood, serum or leukocytes revealed that the release of free 99mTc resulted from the combined action of serum and leukocytes. The rapid clearance will limit the utility of this preparation in characterizing RES function in man and its modification by disease or therapy.

Adult↗
PubMed1981

Heterogeneous in vitro sensitivities of metastatic B16 melanoma sublines and clones to retinoic acid or BCNU.

Murine B16 melanoma sublines have been cloned or selected in vivo for preference of bloodborne metastatic colonization of lung, ovary, or brain. These sublines show differing metastatic properties and cell surface alterations that correlate with a preference for metastatic colonization sites. When the sensitivities of these selected sublines to certain drugs (beta-all-trans retinoic acid or 1,3-bis (2-chlorethyl)-1-nitrosourea (BCNU) were examined, the in vivo-selected sublines were more resistant to growth inhibition in vitro by cytostatic (retinoic acid) or cytotoxic (BCNU) drugs than was the parental B16 line.

Animals↗
PubMed1979

The use of leukocyte cell line culture supernatant for skin reaction testing in malignant melanoma.

A study was conducted to determine some of the potential applications of a human leukocyte culture supernatant or "lymphokine" preparation in cancer patients. The application evaluated in this study was the use of this preparation as a skin test reagent for evaluation of the inflammatory response following intradermal injection. The preparation was derived from the supernatant of a long-term cultured lymphoblastoid cell line with migration inhibition factor (MIF) and other lymphokine activities. Dose response, histology and toxicity studies were done in 53 patients with malignant melanoma stage IIIB and IV. A dose response curve was observed for both erythema and induration at 12 and 24 hours, but not at 48 hours. An optimal intradermal dose for eliciting inflammation was determined and found to be five units. Histopathological evaluation of biopsy specimens showed a mixed cell reaction including granulocytes, eosinophils, lymphocytes and monocytes differing in lymphocyte content from the classical delayed type hypersensitivity (DTH) reaction in man. Compared with the response to recall antigens, only a weak correlation with the DTH response to the recall antigens was found. Our results support the conclusion that lymphokines may be used in the future to evaluate the ability to develop nonspecific inflammation in cancer patients, and that this inflammatory response can be obtained in a number of patients no longer capable of responding to recall antigens.

Adult↗
PubMed1978

Response of malignant melanoma to plasma exchange, surgical debulking, and Corynebacterium parvum.

A 48 year old man with extensive cutaneous and subcutaneous metastatic malignant melanoma responded to treatment by repeated plasma exchanges, partial surgical debulking of tumor masses, and intravenous Corynebacterium parvum. Circulating immune complexes were measured by the serum C1q binding method. Tumor regression coincided with serum C1q binding reduction to normal levels. Clinical relapse was preceeded by recurrent elevation of serum C1q binding activity.

Binding Sites↗
PubMed1977

The combined effect of radiotherapy and neuraminidase-treated tumor cells on 3-methylcholanthrene-induced fibrosarcoma.

Active immunotherapy with tumor cells treated in vitro with Vibrio cholerae neuraminidase (VCN) plus mitomycin C augments the antitumor effects of local x irradiation in the treatment of firmly established methylcholanthrene-induced fibrosarcoma, MC-43, in syngeneic C3H/HeJ female mice. In most experiments, the inhibition of tumor growth was greater when VCN-treated tumor cells were combined with local irradiation than could be achieved with VCN-treated tumor cells or local irradiation alone. Even in those experiments in which the immunotherapeutic effect of VCN-treated cells was negligible, the combination of radiotherapy and immunotherapy appeared to be greater than irradiation alone. Similarly, total permanent regression of established tumors occurred more frequently after combined therapy than after immunotherapy or radiation therapy alone.

Animals↗
PubMed1976

Experimental cancer immunotherapy: modification of tumor cells to increase immunogenicity.

Firmly established transplantable C3H/HeJ mammary carcinomas can be inhibited by host challenge with Vibrio cholerae neuraminidase (VCN)-treated tumor cells. The effect is totally immunospecific, even VCN-treated tumors bearing shared mammary tumor virus (MTV) antigen cannot induce the regression. Thus, VCN is capable of increasing the immunogenicity of the private, unique-unshared tumor antigens on mammary carcinomas; VCN is incapable of increasing the immunogenicity of the shared MTV-associated tumor antigen even in syngeneic C3HeB/FeJ MTV-free mice. The immunoregressive effect of VCN-treated tumor cells can be augmented by subtotal or total surgical excision of large transplantable tumors. Spontaneous mammary tumors in retired breeder C3H/HeJ female mice can be made to regress by two immunological maneuvers: (1) repeated intratumor injections of VCN and/or BCG; and (2) total excision and immunotherapy with VCN-treated autochthonous mammary tumor cells. The use of VCN-treated transplantable mammary tumor cells sharing the MTV-associated antigen was not better than excision alone. The evidence supports the idea that active specific immunotherapy of spontaneous tumors with VCN-altered tumor cells may require the use of autochthonous cells.

Adenocarcinoma↗
PubMed1975

Modifying the immunogenicity of cell membrane antigens. Tumors and transplants.

The immunogenicity of an antigenic cell is a distinctly different property from its antigenic composition. Two clinical problems might well be beneficially affected by modifying the immunogenicity of cell membrane antigens: Can the immunogenicity of tumor-specific antigens on malignant cells be increased so that effective immunity to the tumor will lead to its destruction? Conversely, can the immunogenicity of histocompatibility antigens on grafted organs be minimized so that they will survive a foreign host? Evidence is accumulating to indicate that under certain conditions a tumor vaccine can be developed utilizing autochthonous tumor cells, removed from the host, chemically modified in vitro, and reinjected into the original host which will effectively, augment specific immunologic defenses against residual tumor cells. Similarly, the moderately immunosuppressed host will tolerate grafts after suitable immunogenic modification in vitro. Both approaches may have ready clinical application, even before the mechanisms have been worked.

Adenocarcinoma↗