ABSTRACT
A virus with a circular Rep-encoding single-stranded DNA (ssDNA) (CRESS-DNA) genome (PmCV-1) was isolated from Penaeus monodon shrimps in Vietnam. The gene structure of the 1,777-nucleotide (nt) genome was similar to that of circoviruses and cycloviruses, but the nucleic acid and protein sequence identities to these viruses were very low.
ABSTRACT
A new experimental model is introduced for liver metastases using intrasplenically injected Lewis lung tumor cells. The appearance of liver metastases was studied in the presence and after the removal of primary tumor. The tumorous foci in the liver proved to be natural metastases and increased in number blocking the activity of the Kupffer cells by carragheenan. This model provides a useful tool to study different aspects of liver metastases.
Subject(s)
Liver Neoplasms/secondary , Lung Neoplasms/pathology , Animals , Carrageenan/pharmacology , Cell Division/drug effects , Kupffer Cells/drug effects , Male , Mice , Mice, Inbred C57BL , Neoplasm Transplantation , Neoplasms, Experimental/pathology , Organ Size , Spleen/pathology , SplenectomyABSTRACT
Human colorectal tumors transplanted in immune-suppressed mice (xenogeneic system) and metastasizing Lewis lung carcinoma (syngeneic system) were used to study the effect of macrophages on tumor progression. Carrageenan modifying the structure of macrophage cell coat and damaging the membrane of lysosomes led to severe disturbances in macrophage functions. The inhibition of macrophage activity by Carrageenan produced an enhancement in tumor take in both systems. In another set of experiments peritoneal macrophages were injected into tumor-bearing mice. In both systems the non-stimulated macrophages given i.v., produced a delay in tumor growth. These results indicated that the activity of macrophages influences markedly the tumor progression--even in hosts with damaged T cell population.
Subject(s)
Macrophages/physiology , Neoplasms/pathology , Animals , Carrageenan/pharmacology , Humans , Immunosuppression Therapy , Lung Neoplasms/drug therapy , Macrophages/drug effects , Mice , Neoplasm Transplantation , Transplantation, HeterologousABSTRACT
The growth of human colorectal tumor xenograft lines was studied in immunosuppressed mice after reconstitution with sensitized and nonsensitized macrophages, thymocytes and splenocytes obtained from normal mice. Intravenously injected macrophages caused temporary inhibition of tumor growth. This effect needed intact cells and was independent from the presence of the spleen. The weight of spleen increased in normal mice sensitized with xenograft tumor, and the sensitized splenocytes injected into tumor-bearing immunosuppressed mice caused substantial tumor-growth delay.
Subject(s)
Lymphocytes/physiology , Macrophages/physiology , Neoplasm Transplantation , T-Lymphocytes/physiology , Transplantation, Heterologous , Animals , Carrageenan/pharmacology , Colonic Neoplasms/pathology , Humans , Immunosuppression Therapy , Mice , Mice, Inbred CBA , Rectal Neoplasms/pathology , SplenectomySubject(s)
Carrageenan/pharmacology , Graft Rejection/drug effects , Adenocarcinoma/ultrastructure , Animals , Colonic Neoplasms/ultrastructure , Immunosuppression Therapy , Macrophages/drug effects , Male , Mice , Mice, Inbred CBA , Microscopy, Electron , Neoplasm Transplantation , Rectal Neoplasms/ultrastructure , Transplantation, HeterologousABSTRACT
In our examinations the cytochemical characters of the peritoneal macrophages of immunosuppressed mice (Is-PM) were studied. It was stated that the acid phosphatase activity of their lysosomal system decreased in comparison to control cells (N-PM). In Is-PM cells the polyanion content of the cell-coat and the expression of their ConA receptors decreased, while the glycos- and galactosaminoglycan (GAG) content showed a decrease on the surface of every cell of the population. On the first day following carrageenan treatment, acid phosphatase activity of the cells was very low, the GAG content and the conA receptors of the cell-coat disappeared. The characteristic lysosomal alterations could still be observed on the 6th day after treatment. On the basis of our observations treatment with carrageenan impaired not only the lysosomal system of macrophages, but the cell surface too. These cytochemical changes may explain the dramatic decrease in macrophage function observed in carrageenan treatment.
