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)

By means of immunocytochemical methods, immunoreactivity for the brain isoform of nitric oxide synthase (NOS-I) was recognized in numerous Leydig cells of the human testis as well as in MA-10 tumor and TM3 non-tumor mouse Leydig cell lines. Within the Leydig cell cytoplasm, immunocytochemical results suggested the occurrence of factors known to activate NOS-I such as glutamate and aspartate, as well as molecules involved in the regulation of the NOS-I activity such as calmodulin and Ca2+/calmodulin-dependent protein kinase II. Leydig cells, Sertoli cells, some endothelial cells of the testis, MA-10- and TM3 mouse Leydig cell lines exhibited a relatively strong NADPH-diaphorase enzyme activity as well. Double sequential immunostainings provided evidence that NOS-like immunoreactivity of the testicular Leydig cells is colocalized with testosterone, calmodulin, aspartate, glutamate, and Ca2+/calmodulin-dependent protein kinase II. Sodium nitro-prusside treatment did not result in increased cGMP formation by MA-10- or TM3 mouse Leydig cells, suggesting that NO produced by these cells acts primarily in a paracrine fashion. The NO produced by NOS-I immunoreactive Leydig cells may act as a messenger: 1) between neighbouring NOS-I positive and/or negative Leydig cells as well as to mediate the action of numerous intracellular and extracellular neuroactive substances and growth factors; 2) between Leydig cells and the muscle cells or pericytes of blood vessels to regulate local blood flow and permeability; and 3) between Leydig cells and pertibular myofibroblasts to influence their contraction and the permeability of the lamina propria.
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PMID:Nitric oxide synthase (NOS-I) in Leydig cells of the human testis. 754 13

Nitric oxide (NO) is produced by numerous different cell types, and it is an important regulator and mediator of many processes including smooth muscle relaxation, neurotransmission, and murine macrophage-mediated cytotoxicity for microbes and tumor cells. Although murine macrophages produce NO readily after activation, human monocytes and tissue macrophages have been reported to produce only low levels of NO in vitro. The purpose of this study was to determine if stimulated human mononuclear phagocytes produce inducible nitric oxide synthase (iNOS) mRNA, protein, and enzymatic activity. By reverse transcriptase-polymerase chain reaction (RT-PCR) analysis, we show that human monocytes can be induced to express iNOS mRNA after treatment with lipopolysaccharide (LPS) and/or interferon-gamma (IFN-gamma). By immunofluorescence and immunoblot analyses, we show monocytes and peritoneal macrophages contain detectable levels of iNOS antigen after stimulations with cytokines in vitro. Control monocytes or those cultured with LPS and/or various cytokines have low levels of NOS functional activity as measured by the ability of cell extracts to convert L-arginine to L-citrulline, and they produce low levels of the NO catabolites nitrite and nitrate. Peritoneal macrophages have significantly enhanced nitrite/nitrate production and NOS activity after treatment with LPS and/or IFN-gamma, whereas monocyte nitrite/nitrate production and NOS activity are not altered by the treatments. Monocytes cultured with various live or heat-killed bacteria, fungi, or human immunodeficiency virus (HIV)-1 do not produce high levels of nitrite/nitrate. Antibodies against transforming growth factor-beta (TGF-beta), a factor known to inhibit iNOS expression and NO production in mouse macrophages, do not enhance NO production in human monocytes or macrophages. Biopterin, an obligate cofactor of iNOS enzymatic activity, is undetectable in freshly isolated or cultured human monocytes and peritoneal macrophages. However, replenishment of intracellular levels of tetrahydrobiopterin by culture with the cell-permeable, nontoxic precursor sepiapterin does not enhance the abilities of the human mononuclear phagocytes to produce NO in vitro. Mixing experiments show no evidence of a functional NOS inhibitor in human mononuclear phagocytes. Thus, we demonstrate that human mononuclear phagocytes can produce iNOS mRNA and protein, and (despite this) their abilities to generate NO are very low.
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PMID:Human mononuclear phagocyte inducible nitric oxide synthase (iNOS): analysis of iNOS mRNA, iNOS protein, biopterin, and nitric oxide production by blood monocytes and peritoneal macrophages. 754 98

Evidence has previously been presented for an immunomodulatory role of a soluble activity, designated as tumor-derived recognition factor (TDRF), which was produced constitutively by P815 mastocytoma, L 1210 leukemia and other murine tumor targets. TDRF synergized with IFN-gamma and IL-2 to promote TNF-alpha and mRNA synthesis and release by murine macrophages for increased autocrine induction of nitric oxide (NO)-mediated tumor cytotoxicity. We have now further assessed the modulatory role of TDRF on TNF-alpha, TNF receptors (TNF-R) and NOS mRNA synthesis. Macrophages activated by INF-gamma priming and triggering by rTNF-alpha bacterial lipopolysaccharide (LPS) of IL-2 evoked greater NO generation in the presence than in the absence of L1210 targets. TDRF-containing culture fluid from L1210 targets was subsequently confirmed to synergize with IFN-gamma and rTNF-alpha, LPS or IL-2 triggering agents to promote increased TNF-alpha mRNA for autocrine induction of NOS mRNA synthesis with resultant augmentation of NO generation. IFN-gamma selectively upregulated TNF-R1 mRNA expression, whereas either IL-2 or LPS upregulated only TNF-R2 mRNA expression. TDRF combined with IFN-gamma to further upregulate TNF-R1 mRNA and with either IL-2 or LPS to further upregulate TNF-R2, mRNA expression. These findings indicate that TDRF activity synergizes with either IL-2 or LPS triggering agents for enhanced activation of IFN-gamma-primed macrophages by promotion of TNF-alpha and TNF-R mRNA synthesis for autocrine induction of NOS with resultant increased NO-mediated tumor cytotoxicity.
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PMID:Tumor-derived factor synergizes with IFN-gamma and LPS, IL-2 or TNF-alpha to promote macrophage synthesis of TNF-alpha and TNF receptors for autocrine induction of nitric oxide synthase and enhanced nitric oxide-mediated tumor cytotoxicity. 754 21

Mice pre-exposed to cisplatin increased their production of nitric oxide (NO) when treated with lipopolysaccharide (LPS). Peritoneal macrophages, isolated from mice 11 days after cisplatin treatment and cultured with LPS plus IFN-gamma, increased NO production, whereas the macrophages isolated 2 days after cisplatin treatment decreased it. In both cases, NO was not produced without immunostimulant(s). Northern and Western Blot analysis showed that macrophages exposed to cisplatin for 11 days increased production of mRNA and protein expression of inducible nitric oxide synthase (iNOS). THis result indicated that macrophages became more sensitive to LPS and IFN-gamma when they were exposed to cisplatin in vivo. Peritoneal macrophages, when activated with LPS plus IFN-gamma and then cocultured with several tumor cells, exhibited cytotoxic activity against both cisplatin-sensitive and cisplatin-resistant tumor cells. There was no difference in cytotoxicity between the paired cells. Under the same experimental condition, macrophages that were exposed to cisplatin for 11 days had significantly increased their cytotoxicity to the tumor cells. This cytotoxic activity was inhibited by the NOS inhibitor NG-monomethyl-L-arginine, indicating that NO is a major effector for macrophage-mediated tumor cell killing. Treatment of tumor cells with S-nitroso-N-acetylpenicillamine, a NO-generating compound, showed the similar tumoricidal effect. These data demonstrated that injection of cisplatin into the mice can enhance the sensitivity of macrophages to the subsequent treatment of immunostimulant(s) for effective tumor cell killing through enhanced NO production.
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PMID:In vivo cisplatin-exposed macrophages increase immunostimulant-induced nitric oxide synthesis for tumor cell killing. 758 26

Macrophages can become activated to kill both tumor cells and a variety of microbes. Results here show that synthesis of nitric oxide (NO), a mediator of many macrophage cytotoxic functions, was greatly increased when cells of the mouse macrophage cell line RAW 264.7 were costimulated with bacterial lipopolysaccharide (LPS) and interferon-gamma (IFN-gamma), compared to LPS alone. This increase paralleled increases in cytotoxicity. Northern analysis showed that increased production of NO was preceded by markedly enhanced expression of mRNA for the inducible form of macrophage NO synthase (mac-NOS), which catalyzes the synthesis of NO. Cycloheximide inhibited the induction of mac-NOS mRNA by IFN-gamma and LPS, indicating that expression of this mRNA required de novo protein synthesis. Elevated expression of mac-NOS mRNA was not due to an increase in its stability. Rather, the combination of IFN-gamma and LPS induced a much higher rate of transcription of the mac-NOS gene than did stimulation with LPS alone. These results provide one explanation of why priming and triggering stimuli, such as IFN-gamma and LPS, respectively, synergistically activate macrophages and may be applicable to explaining how IFN-gamma augments NO-dependent microbicidal activity in macrophages as well.
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PMID:Expression of the nitric oxide synthase gene in mouse macrophages activated for tumor cell killing. Molecular basis for the synergy between interferon-gamma and lipopolysaccharide. 767 12

Observations during the last several years on the relationships between bone marrow-derived dendritic cells (DC) and the cells which are in direct contact with them led to the idea that DC may have regulatory properties. Such regulatory properties exerted by DC were noted in experimental cancers in murine systems as well as in human cancers. It was noted that patients with the same type of cancer in which DC are present in the tumor survive longer than patients without DC in the tumor. It is not known how DC can abrogate the development of the metastatic tumor cells in the primary tumor, nor how the tumor cells are capable of abrogating the anticancer activity of the DC and allowing the development of tumor metastases. Studies on the anticancer activity of macrophages revealed that these cells have an inducible Nitric Oxide (NO) synthase (NOS) which utilizes arginine to produce NO. Suppressor macrophages release NO, which inhibits the ribonucleotide reductase and mitochondrial oxidation in tumor cells in vitro. It was also reported (4) that Interferon gamma (IFN-gamma), produced by murine T helper 1 cells, induces NOS activity in macrophages, while T helper 2 cells which produce Interleukin-4 (IL-4) inhibit the expression of NOS in macrophages. The hypothesis presented in this paper suggests that DC have a gene for NOS which is inducible by immunomodulators (e.g. IFN gamma, OK432, LPS) and can be suppressed by cytokines produced by tumor cells (e.g. IL-4, IL-10).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Success and failure of dendritic cell (DC) anticancer activity may be modulated by nitric oxide synthetase (NOS) gene expression: a hypothesis. 768 49

Mucocele-like tumor and invasive mucinous carcinoma of the breast may represent the two ends of the pathological spectrum of mucinous lesions of the breast, respectively. Little data exists on mucinous lesions that may be considered intermediate between mucocele-like tumor and invasive mucinous carcinoma. We studied 23 consecutive cases of invasive mucinous carcinoma of the breast and observed the following associated intermediate mucinous lesions: mucin-filled ducts (MFD) with unremarkable epithelium in 15 cases (65%), MFD with typical ductal hyperplasia in 9 cases (39%), MFD with atypical ductal hyperplasia in 5 cases (22%), and MFD with intraductal carcinoma in 13 cases (57%; micropapillary or cribriform types). Eighteen cases (78%) contained MFD with one of these four lesions and five cases (22%) contained all four lesions. Twenty-three consecutive cases of infiltrating ductal carcinoma-not otherwise specified (IDC-NOS), 21 cases of intraductal carcinoma, and 50 consecutive cases of surgically-excised breast tissue with fibrocystic change (FC), were similarly reviewed. Only one case (4%) of IDC-NOS, 1 case of intraductal carcinoma, and two cases (4%) of FC, contained small foci of MFD with intraductal carcinoma, intraductal carcinoma, and unremarkable epithelium, respectively. Our findings suggest the presence of a spectrum of mucinous lesions of the breast which represents a pathological continuum.
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PMID:Mucinous lesions of the breast. A pathological continuum. 830 9

In this study epidermal growth factor receptor (EGF-R), estrogen receptor (ER), and progesterone receptor (PR) status was evaluated in 326 primary breast carcinomas. Nineteen percent of samples were EGF-R positive, 63% were positive for ER, and 54% for PR. In 46% of the tumors both ER and PR were positive. These data are presented together, with grading, size of tumor, lymph node involvement, histological subtype, and age. Sixty-nine percent of EGF-R negative tumors were ER-positive and 51% were positive for ER as well as PR. In particular, negative correlation between EGF-R and steroid receptor status was found. A quantitative correlation was also shown. A combination of negative steroid receptor and positive EGF-R was found more often in the population of poorly differentiated tumors. Tumors bigger than 5 cm were related to a positive EGF-R status. No correlation between nodal status and any receptor status was found. Intraductal carcinomas were more often EGF-R positive than infiltrating ductal (NOS) or infiltrating lobular lesions. The age of patients correlated with the concentration of ER only. In our study we reaffirmed the negative correlation between steroid receptor status and the overexpression of EGF-R; furthermore the combination of EGF-R+ and ER- tumors was observed more often in histological high-risk tumors. Patient outcome did not show statistically significant differences concerning the EGF-R status, but was associated with the steroid receptor status.
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PMID:EGF-R and steroid receptors in breast cancer: a comparison with tumor grading, tumor size, lymph node involvement, and age. 839 51

Cell loss patterns of five tumors and their histological findings were investigated in WHT/Ht strain mice. The tumors investigated were squamous cell carcinoma H, squamous cell carcinoma NOS, squamous cell carcinoma TAK, rhabdomyosarcoma KAS, and fibrosarcoma YAS. The present study revealed that histological findings of tumor tissues are not necessarily corded structure presented by Thomlinson and Gray. The five were divided into two groups according to their histological findings, i.e. a corded structure (squamous carcinoma H and NOS) and a non-corded structure (squamous cell carcinoma TAK, rhabdomyosarcoma KAS and fibrosarcoma YAS). The cell loss patterns (125I-iododeoxyuridine retention curves) were also divided into two groups which corresponded to the histological structures. Two tumors with the corded structure (squamous cell carcinoma H and NOS) have a cell loss pattern with a constant shoulder portion (a migration time of tumor cells through a tumor cord from capillary to necrotic region). In these tumors, the cell loss occurred in the necrotic regions. In the other tumors with the non-corded structure, cell loss curves have no constant shoulder portion and cell loss might occur throughout the tumor. The origin of hypoxic cells in these two types of histology are presumably different. The diffusion-limited hypoxia, i.e. chronically hypoxic cells, may be the main cause for the tumors with corded structure. On the other hand, hypoxia as a result of temporary cessation of blood flow within the tumor vasculature, i.e. acutely hypoxic cells, may mainly occur in the tumor with non-corded structure.
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PMID:Two different types of cell loss patterns of murine tumors and their corresponding histological findings and possible mechanisms of production of hypoxic cells. 850 92

Murine macrophages (M phi) are activated either by interferon-gamma (IFN-gamma) or interferon-alpha/beta (IFN-alpha/beta) in combination with bacterial lipopolysaccharide (LPS) to induce synthesis of tumor necrosis factor alpha (TNF-alpha) and nitric oxide synthase (iNOS) mRNA synthesis for generation of tumor cytotoxic nitric oxide (NO). In the present study, the effect of exogenous IFN-gamma on the induction of endogenous mRNA synthesis and secretion of IFN-alpha/beta by murine M phi was investigated. Neutralizing antibodies to IFN-alpha/beta reversed TNF-alpha and NOS mRNA synthesis, as well as nitric oxide (NO)-mediated tumor cytotoxicity. Quantitative reverse transcription polymerase chain reaction (RT-PCR) revealed that treatment of M phi with IFN-gamma induced increases in both IFN-alpha and IFN-beta mRNA synthesis by approximately 2-fold and 10-fold, respectively, which corresponded to a 2-fold increase in secretion of IFN-alpha/beta by ELISA. These data indicate that exogenous IFN-gamma induces endogenous synthesis and secretion of IFN-alpha/beta by M phi, which appears to act in concert with endogenously synthesized TNF-alpha for the autocrine induction of NOS mRNA synthesis.
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PMID:Exogenous interferon-gamma induces endogenous synthesis of interferon-alpha and -beta by murine macrophages for induction of nitric oxide synthase. 856 12


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