Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0027651 (tumor)
 685,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Dunn osteosarcomas synthesize 2 times more alkaline phosphatase than do Ridgeway osteosarcomas, 3 times more than do HeLa cells, and 4 to 5 times more than do rat or mouse fibroblast cell cultures. Implants of killed freeze-dried Dunn cell cultures into the thigh muscles are resorbed and replaced by normal cartilage, bone, and bone marrow tissue, while implants of freeze-dried Ridgeway cells are resorbed and replaced by fibrous tissue only. Outgrowths of normal muscle septum connective tissue cells onto the stroma of Ridgeway tumors differentiate into fibrous tissue. Cultures of either tumor on a substratum of bone matrix stroma prepared from normal bone proliferate, assume a spherical shape, and perpetuate the transformed osteoblast-like cell without forming attachments or adapting to the contour of the substratum. Outgrwoths of muscle mesenchymal cells on the Dunn tumor stroma differentiate into cartilage. Dunn osteosarcoma cell cultures proliferate on the inside and produce deposits of normal bone (not tumorous bone) on the outside of diffusion chambers. Killed freeze-dried cell cultures produce transfilter deposits of normal bone and bone marrow, but the quantity is significantly lower. On a substratum of cellulose acetate, outgrowths of muscle connective tissue will differentiate into cartilage when cell-free Dunn stroma is present under the organ culture grid. Tumorigenesis and normal cartilage and bone morphodifferentiation are antithetic, but tumor cells transfer a bone morphogen similar to the bone morphogenetic protein (BMP) of normal bone matrix. BMP recruits mesenchymal cells to proliferate and differentiate into cartilage and bone.
 ...
PMID:Osteogenesis and chondrogenesis in transplants of Dunn and Ridgway osteosarcoma cell cultures. 27 82

Tumor induction in BALB/c mice by diethylnitrosamine (DENA) was shown to be sex related. Female mice killed 13.5 months after DENA exposure generally had higher incidences of forestomach and lung tumors than did males and also had higher numbers of lung tumors per tumor-bearing mouse. Although neither sex developed stomach tumors spontaneously, males had higher incidences of spontaneous lung tumors than did females (45 vs. 26%). When butylated hydroxytoluene (BHT) was given concomitantly with DENA treatment, females had an increased survival (68 vs. 43%) and a reduced incidence of forestomach squamous cell carcinomas (77 vs. 100%) compared with females given DENA alone. No such protective effect on survival or on the occurrence of stomach tumors was seen in males given BHT and DENA or on lung tumorigenesis in either sex. In males, BHT given alone increased survival of treated mice over that of untreated controls, but it had no such effect on the females. The results of this study suggested an as yet unexplained hormonal influence and/or dependence for this BHT modification of DENA tumorigenesis.
 ...
PMID:Selective sex-related modification of diethylnitrosamine-induced carcinogenesis in BALB/c mice by concomitant administration of butylated hydroxytoluene. 27 24

The temporal acquisition of in vitro phenotypes associated with neoplasia were examined after exposure of Syrian hamster embryo cells to a chemical carcinogen. Quantitative assays measuring morphological changes, enhanced fibrinolytic activity, and anchorage independent growth were used to detect the development of transformed cells within a population of normal hamster embryo cells. Morphological transformation and enhanced fibrinolytic activity were early changes observed after treatment with benzo[alpha]-pyrene, whereas the ability to grow in semisolid agar was delayed 32-75 population doublings after carcinogen exposure. This delay was not due to selection of a small number of cells that were present early after treatment but at a level below detection, because a large percentage of the cells isolated at early passage (10(3)-fold above the level of detection) developed the potential for anchorage independent growth at later passages. This development of the anchorage independent growth phenotype was induced by the carcinogen treatment, because spontaneous transformation was rare. These observation suggest that multiple cellular changes are required for the acquisition of the capacity for anchorage independent growth and that neoplastic transformation in vitro is a progressive process through qualitatively different stages. Thus, an analogy can be drawn to the progressive nature of in vivo carcinogenesis. These results strongly justify the study of oncogenesis in cell culture as a model for neoplastic transformation in vivo.
 ...
PMID:Evidence for the progressive nature of neoplastic transformation in vitro. 27 86

The effect of intestinal microflora on liver tumorigenesis was studied in gnotobiotic C3H/He male mice monoassociated, diassociated, or polyassociated with the following strains of intestinal bacteria: Escherichia coli, Streptococcus faecalis, Bifidobacterium adolescentis, Bifidobacterium infantis, Clostridium indolis, C. paraputrificum, C. perfringens, C. innocuum, C. nexile, C. ramosum, C. clostridiiforme, Bacteroides multiacidus, Bacteroides fragilis, Veillonella alcalescens, V. parvula, and Lactobacillus acidophilus. The incidence of liver tumors was higher in most of the gnotobiotes (67--100%) and conventionalized mice (82%) derived from the germfree mice than in the germfree mice (39%). The average incidence of tumor nodules in gnotobiotes associated with E. coli, S. faecalis, and C. paraputrificum was 2.9, which was significantly higher than that in the conventionalized animals (1.6). In contrast, the average incidence of tumor nodules in gnotobiotes associated with E. coli, S. faecalis, L. acidophilus, C. perfringens, and Bacteroides fragilis (0.9) was not significantly different from that in germfree animals (0.5). The present study demonstrated that the presence of certain intestinal bacteria is related to liver tumorigenesis in gnotobiotic C3H/He male mice.
 ...
PMID:Effect of intestinal bacteria on incidence of liver tumors in gnotobiotic C3H/He male mice. 29 9

A cerebellopontine angle tumor cannot be reliably diagnosed from a classical clinicotopographic cerebellopontine angle syndrome. There is also a vascular cerebellopontine angle syndrome which is not too rare an occurrence. In some cases of tumorigenesis, where there is no papilledema and no characteristic increase in total liqour protein, it is not possible to make a clear decision between tumorous growth and vascular syndrome. The extension of the internal auditory meatus cannot be considered to be a symptom clearly indicating the presence of a tumor.
 ...
PMID:[The vascular cerebellopontile angle syndrome]. 30 8

Sarcomas were induced in CBA/H mice by sc implantation of 15 X 22 X 0.2-mm polyvinyl chloride vinyl acetate copolymer films. The animals were immunosuppressed with azathoprine, antilymphocyte globulin, or thymectomy. Sarcoma development was not accelerated in comparison to nonimmunosuppressed demonstrated in sarcomas of immunosuppressed mice. It was concluded that foreign body tumorigenesis in mice in neither associated with nor dependent on the emergence of tumor-specific transplantation antigens.
 ...
PMID:Immunosuppression studies in foreign body tumorigenesis: no evidence for tumor-specific antigenicity. 32 Mar 46

Eighty newborn C3H/BifB/Ki strain mice received a single intraocular inoculation of 0.002--0.003 ml of 10(8.0) TCID 50/0.1 ml human adenovirus 12 (AD 12), within 24 h after birth. Forty mice survived and in seven of these (17.5%) a solid retinoblastomalike neoplasm developed between 64 and 236 days. The tumors have been successfully cultured and also transplanted subcutaneously into syngeneic hosts. Morphologically, all tumors revealed characteristic features of retinoblastoma associated with the Homer Wright type of rosettes. Bizarre giant cells were commonly detectable. Ad 12-specific T-antigens were demonstrated in both the primary and cultured tumor cells using immunofluorescent techniques. Some giant cells also showed numerous T-positive filaments. Electron microscopy disclosed poorly differentiated unipolar cells possessing a large ovoid nucleus. Many tumor cells appeared to contain a well organized solitary cilium consisting of a typical ring of nine doublets with no axial (9 + 0) in close association with a pair of centrioles. Some multinucleated giant tumor cells also contained multiple cilia-centriole complexes within their broad syncytial cytoplasm. Occasional endogenous C particle-like virions unique to murine neuroblastomas were observed for the first time in virus-induced retinal tumors. This unprecedented tumor model in a pure strain mouse adds to the range of known animals sensitive to Ad 12 oncogenesis.
 ...
PMID:Retinoblastoma-like neoplasm induced in C3H/BifB/Ki strain mice by human adenovirus serotype 12. 33 42

The paper reviews the histopathology and cytopathology of a number of experimental animal brain tumor models to determine their relevance to human neuro-oncology. The models discussed include brain tumors produced by local implants of carcinogenic hydrocarbons and by the administration of resorptive N-nitroso compounds, some of the cell lines derived from the latter, tumors resulting from the intracerebral inoculation of oncogenic viruses, and the differentiating neuroepithelial component of a transplantable mouse teratoma. The structural and biochemical criteria that can be applied for the identification of the various stages of neuronal and glial cell maturation are highly precise. They reveal a wide diversity of tumor cell types that are now available in experimental neuro-oncogenesis.
 ...
PMID:Correlation of animal brain tumor models with human neuro-oncology. 34 99

The influence of population density in the progression from the nonneoplastic to the neoplastic state has been reassessed. Two twice-cloned, nonneoplastic mouse lines, NCTC 7914 and 7915, were transferred each 3 to 4 days at inoculum sizes selected to minimize or maximize cell-cell contact, 1 X 10(5) or 4 X 10(5) cells/T-15, respectively. As tested by in vivo assay, the regime designed to minimize cell-cell contact did not reproducibly delay transformation, and tumor production was observed in all lines, irrespective of inoculum size. Also, results of tumorigenesis assays correlated with blind evaluation of morphological and cytological alterations, growth in agarose, and susceptibility to killing by activated macrophages. Generally higher saturation densities were seen as a function of period in culture, and no significant differences in glucose utilization or lactic acid production were observed between nonneoplastic and neoplastic cell populations.
 ...
PMID:Population density as a factor in the evolution of neoplastic cell lines. 35 29

Infection of mice with Salmonella enteritidis 11RX has been shown previously to cause nonspecific immune stimulation and, consequently, resistance to subsequent challenge with a variety of transplantable tumors. The present study has examined the effect of infection with this organism in a chemical carcinogenesis system. Colonic tumors were induced in LACA and BALB/c x C57BL/6JF1 mice by weekly s.c. injection of 1,2-dimethylhydrazine (15 mg/kg) for 28 weeks. Infection of mice p.o. with live S. enteritidis 11RX at 8-week intervals during 1,2-dimethylhydrazine administration protected both strains against colon tumorigenesis. Significantly fewer infected than control BALB/c x C57BL/6JF1 mice had colonic tumors at or before termination of the experiment (34 or 40 weeks) (p less than 0.001 in all cases). Comparable results were obtained with both male and female mice. The difference in tumor incidence between control and infected LACA mice was not statistically significant, however; the number and size of the lesions was greater in control mice (p less than 0.02). Although it has not been proven that the protective effect is mediated by the immune system, the results are consistent with the operation of a macrophage-mediated surveillance system. It is suggested that enteric infections should be considered as a possible contributing factor in the epidemiology of human colonic cancer.
 ...
PMID:Protective effect of oral Salmonella enteritidis 11RX infection against colon tumor induction by 1,2-dimethylhydrazine in mice. 37 22


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>