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

Mannich bases of 5-hydroxynaphthalene-1,8-carbolactone 1 were prepared from various secondary amines or bulky primary amines and formaldehyde. They were isolated in almost all cases as hydrochlorides. These derivatives were submitted to in vitro antifungal and cytotoxic assays. The antifungal assays were performed against three strains of yeasts and five strains of human pathogenic fungi. Two of the tested compounds, 2i and 2j, exhibited interesting antifungal activities against Candida albicans and Candida tropicalis. The cytotoxic activity was evaluated towards L 1210 leukemia cells. Almost all of the Mannich bases had shown significant activity against this tumor cell line as values of IC50 less than or equal to 4 micrograms/ml are considered interesting. Only one derivative 2 developed better cytotoxicity than the parent compound 1.
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PMID:Synthesis of Mannich bases of 5-hydroxynapthalene-1,8-carbolactone as potential antifungal or antitumor agents. 205 74

Mechanistic possibilities responsible for nonlinear shapes of the dose-response relationship in chemical carcinogenesis are discussed. (i) Induction and saturation of enzymatic activation and detoxification processes and of DNA repair affect the relationship between dose and steady-state DNA adduct level; (ii) The fixation of DNA adducts in the form of mutations is accelerated by stimulation of the cell division, for instance due to regenerative hyperplasia at cytotoxic dose levels; (iii) The rate of tumor formation results from a superposition of the rates of the individual steps. It can become exponential with dose if more than one step is accelerated by the DNA damage exerted by the genotoxic carcinogen. The strongly sigmoidal shapes often observed for dose-tumor incidence relationships in animal bioassays supports this analysis. A power of four for the dose in the sublinear part of the curve is the maximum observed (formaldehyde). In contrast to animal experiments, epidemiological data in humans rarely show a significant deviation from linearity. The discrepancy might be explained by the fact that a large number of genes contribute to the overall sensitivity of an individual and to the respective heterogeneity within the human population. Mechanistic nonlinearities are flattened out in the presence of genetic and life-style factors which affect the sensitivity for the development of cancer. For a risk assessment, linear extrapolation from the high-dose incidence to the spontaneous rate can therefore be appropriate in a heterogeneous population even if the mechanism of action would result in a nonlinear shape of the dose-response curve in a homogeneous population.
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PMID:Dose-response relationships in chemical carcinogenesis: from DNA adducts to tumor incidence. 206 82

In an immunohistochemical study of 59 routinely processed tissue specimens from 48 adult testes with isolated carcinoma-in-situ (CIS) changes and of 66 specimens from adult testes without neoplasia, placental-like alkaline phosphatase (PlAP) was shown to be a reliable marker of CIS cells preceding the development of a testicular tumour. Thus, a positive reaction was encountered in all 36 biopsies treated with formaldehyde, or Bouin's or Stieve's fluid. However, only 11 of 23 specimens fixed with Cleland's fluid were immunoreactive for PlAP. None of the non-malignant components of seminiferous tubules, including the large abnormal spermatogonia, reacted with the antibody against PlAP. Besides the antibody against PlAP, monoclonal antibodies M2A and 43-9F were tested on CIS specimens fixed with the above-mentioned fixatives. In the 17 specimens fixed with Stieve's or Bouin's fluid, a positive reaction was obtained in all sections with all three antibodies tested. However, for each antibody at least two specimens gave a weak staining reaction. When all three immunostainings were performed, in each case at least one of them gave a moderate or strong reaction, thus making CIS cells easily detectable. In the samples fixed with Cleland's fluid, a negative reaction was found in one to three specimens, depending on the antibody used. However, at least one of the three antibodies gave a positive reaction if all three immunostainings were applied. In only one of the formaldehyde-fixed paraffin specimens did CIS cells react with the monoclonal antibody 43-9F, whereas M2A gave no positive reaction at all if this method of fixation was used. Thus, the sensitivity of the immunohistochemical staining procedure in the detection of CIS is dependent on the fixative used and increases when immunostainings with all three markers are performed simultaneously.
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PMID:Placental-like alkaline phosphatase as a marker of carcinoma-in-situ of the testis. Comparison with monoclonal antibodies M2A and 43-9F. 206

We have studied by immunocytochemistry and monoclonal antibodies the presence and localization of estrogen receptors, progesterone receptors, and a 24-kD estrogen-regulated heat shock protein in biopsies from breast and endometrial cancer patients. Three different tissue processing protocols were used to colocalize the antigens in the same tissue sections: a) frozen sections, b) formalin fixation with routine paraffin embedding, and c) picric acid-formaldehyde (PAF) fixation with a rapid embedding in paraffin. Frozen sections showed good receptor staining but poor 24-kD protein immunoreactivity, while routine paraffin sections (with or without DNase pretreatment) were inadequate to reveal the nuclear receptor proteins at the same level seen in frozen sections. On the other hand, all three proteins could be detected satisfactorily in PAF-fixed paraffin-embedded tissue. Using this procedure we were able to visualize 24-kD protein and estrogen receptor or progesterone receptor in individual cells in paraffin sections. The study revealed that in all of the estrogen receptor positive breast and endometrial tumor samples, almost 90% of the cells expressing the cytoplasmic 24-kD protein contained estrogen receptor in the cell nucleus. In contrast, 24-kD immunoreactive cells did not express progesterone receptors in almost 40% of the progesterone receptor positive tumor samples.
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PMID:Colocalization of estrogen and progesterone receptors with an estrogen-regulated heat shock protein in paraffin sections of human breast and endometrial cancer tissue. 208 75

15 cases of human malignant melanoma were studied and classified into 5 superficial speading (SSM), 5 nodular melanomas (NM), and 5 melanoma metastasis (Met). The tissue was fixed with formaldehyde and cetylpyridium chloride (CPC). Glycosaminoglycans (GAG) or proteoglycans respectively were characterized by Alcian blue staining following the method of critical electrolyte concentration (CEC) (Scott, Dorling 1965) and by testes hyaluronidase. The staining intensities were quantified by a Leitz MPV photometer microscope in basement membranes (BM) and tumor septa. Tumor septa, which may be looked on as correlates of epithelial BM material, show increased straining intensities as compared to the normal BM (nBM) around the tumor. It is concluded from the sensitivity to testes hyaluronidase and the straining pattern that these are caused by increased straining of GAG of the type of chondroitin sulfates and possibly of dermatan sulfate while unsulfated GAG are rather decreased. The GAG pattern in BM in SSM shows characteristics of tumor septa and of nBM as well. The staining of the tumors shows higher intensities than that of all structures in the normal skin. It is concluded that increasing malignancy is accompanied by increasing changes in GAG which can be quantified by the method used topohistochemically discerning the healthy tissue from malignant structures.
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PMID:[Histotopochemical quantification of glycosaminoglycans in melanomas and the surrounding epidermis]. 209 11

The mechanism whereby cytolytic lymphocytes protect themselves from killing mediated by their own cytotoxic protein, perforin, was studied. By using a competition assay, we demonstrated that the resistance of cells to perforin-mediated cytolysis is inversely correlated with their ability to absorb perforin, with tumor cells and noncytotoxic lymphocytes that are susceptible to perforin-mediated lysis being able to absorb perforin from the supernatant much better than CTL. The evidence implies that there is molecule on cytolytic lymphocytes that interferes with perforin-binding activity, resulting in the inability of perforin to lyse these cells. The molecule is most likely a surface protein or complex of proteins because its activity decreases after CTL treatment with the proteolytic enzymes trypsin and papain, and the activity can be recovered by incubation of the treated CTL cells at 37 degrees C for 6 h. The recovery can be blocked by emetine, cycloheximide, and actinomycin D, inhibitors of protein and RNA/DNA synthesis. The protein contains carbohydrate groups that play an important role in the function of the protein, as indicated by the fact that inhibition of glycosylation by tunicamycin and cleavage of sialic acid from the protein with neuraminidase result in a significant increase of perforin binding to CTL. Cross-linkage of CTL membrane proteins with glutaraldehyde and formaldehyde and blockage of the functional domains of the protein with an antiserum against CTL also inhibit the activity of this protein. Temperature-dependence studies that allow for a dissociation of the binding and pore-forming stages of perforin-mediated hemolysis suggest that the protective protein interferes at the perforin-binding stage.
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PMID:Resistance of cytolytic lymphocytes to perforin-mediated killing. Inhibition of perforin binding activity by surface membrane proteins. 210 15

The presence of human papilloma virus (HPV) has recently been demonstrated in colon tumors, but the incidence of HPV infection in normal colon mucosa or in benign or malignant neoplasms of the mucosa is unknown. We studied both neoplastic and normal human colon tissue for the presence of HPV antigen using immunohistochemical techniques. Ninety colon specimens were studied. Three consecutive series of normal colon mucosa (N = 30), single benign tubulovillous adenomas (N = 30), and invasive carcinomas (N = 30) were selected and confirmed histologically. Formalin-fixed paraffin-embedded samples of each tissue were prepared using immunohistochemical techniques and resultant slides were read blindly and graded simply as positive or negative for HPV antigen. The presence of HPV antigen varied dramatically between groups, with 97% of the invasive carcinomas, 60% of the benign tubulovillous adenomas, and 23% of the normal mucosa positive for HPV antigen. Groups were statistically significant using chi 2 analysis (P less than 0.001). We conclude that an association exists between the human colon neoplasia and the presence of HPV antigen. This may suggest an etiologic role of the virus in colon cancer.
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PMID:Immunohistochemical demonstration of human papilloma virus antigen in human colon neoplasms. 216 68

Two hundred sixty-two invasive breast carcinomas dating from 1979 to 1984 were tested for vimentin and keratin on formaldehyde-fixed paraffin-embedded sections. None of 26 lobular carcinomas expressed vimentin. Vimentin expression in 10% or more of tumor cells was found in 78% of medullary (14 of 18), in 16% of ductal not otherwise specified (NOS) (35 of 214), and in two of four mucinous carcinomas. A further seven tumors showed vimentin expression in less than 1% to 10% of the cells. Vimentin was expressed in tumor cells of 30% (28 of 93) of grade III invasive ductal NOS carcinomas versus 7% (7 of 105) of grade II and 0% of grade I carcinomas (0 of 10). Vimentin was found to be preferentially expressed in tumors growing in broad, often anastomosing bands or sheets with extensive necrosis, scanty supportive stroma, high nuclear grade, and numerous mitoses. The authors conclude that vimentin is not detected in lobular carcinomas, but is preferentially expressed in medullary and in high-grade ductal NOS breast carcinomas.
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PMID:Vimentin is preferentially expressed in high-grade ductal and medullary, but not in lobular breast carcinomas. 217 10

Of primary concern are irreversible effects, such as cancer induction, that formaldehyde exposure could have on human health. Dose-response data from human exposure situations would provide the most solid foundation for risk assessment, avoiding problematic extrapolations from the health effects seen in nonhuman species. However, epidemiologic studies of human formaldehyde exposure have provided little definitive information regarding dose-response. Reliance must consequently be placed on laboratory animal evidence. An impressive array of data points to significantly nonlinear relationships between rodent tumor incidence and administered dose, and between target tissue dose and administered dose (the latter for both rodents and Rhesus monkeys) following exposure to formaldehyde by inhalation. Disproportionately less formaldehyde binds covalently to the DNA of nasal respiratory epithelium at low than at high airborne concentrations. Use of this internal measure of delivered dose in analyses of rodent bioassay nasal tumor response yields multistage model estimates of low-dose risk, both point and upper bound, that are lower than equivalent estimates based upon airborne formaldehyde concentration. In addition, risk estimates obtained for Rhesus monkeys appear at least 10-fold lower than corresponding estimates for identically exposed Fischer-344 rats.
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PMID:Quantitative cancer risk estimation for formaldehyde. 218 77

A list of endogenous DNA-damaging agents and processes is given. Endogenous electrophiles are found with the cosubstrates of physiological transfer reactions (S-adenosylmethionine for methylation, ATP for phosphorylation, NAD+ for ADP-ribosylation, acetyl CoA for acetylation). Aldehyde groups (glyceraldehyde-3-phosphate, formaldehyde, open forms of reducing sugars, degradation products of peroxidation) or alkylating degradation products derived from endogenous nitroso compounds represent additional possibilities. Radical-forming reactions include leakage of the superoxide anion radical from terminal cytochromes and redox cycles, hydroxyl radical formation by the Fenton reaction from endogenous hydrogen peroxide, and the formation of lipid peroxides. Genetic instability by spontaneous deaminations and depurinations as well as replicative instability by tautomer errors and in the presence of mutagenic metal ions represent a third important class of endogenous genotoxic processes. The postulated endogenous genotoxicity could form the mechanistic basis for what is called 'spontaneous' tumor incidence and explain the possibility of an increased tumor incidence after treatment of animals with non-genotoxic compounds exhibiting tumor-promoting activity only. Individual differences are expected to be seen also with endogenous DNA damage. The presence of endogenous DNA damage implies that exogenous DNA-carcinogen adducts give rise to an incremental damage which is expected to be proportional to the carcinogen dose at lowest levels. An increased tumor risk due to exposure to exogenous genotoxic carcinogens could therefore be assessed in terms of the background DNA damage, for instance in multiples of the mean level or of the interindividual variability in a population.
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PMID:Endogenous genotoxic agents and processes as a basis of spontaneous carcinogenesis. 218 25


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