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Query: UMLS:C0011849 (diabetes)
277,896 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Multiple studies have noted that obese individuals are at a high risk of renal cell cancer. Similarly, numerous case-control and cohort studies have consistently reported that individuals with a history of hypertension experience an increased risk of renal cancer. In spite of this compelling body of epidemiologic data, no credible hypothesis has been advanced to explain this dual etiologic association. In this communication we propose that lipid peroxidation, which is increased in obese and hypertensive subjects, is the mechanism responsible, at least in part. for their increased risk of renal cell carcinoma. In experimental animals lipid peroxidation of the proximal renal tubules is a necessary mechanistic pathway in renal carcinogenesis induced by several different chemicals. Our hypothesis may also explain the roles of other risk (oophorectomy/hysterectomy, parity, smoking, diabetes) and protective factors (dietary antioxidants) for renal cell cancer.
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PMID:Lipid peroxidation: a novel and unifying concept of the etiology of renal cell carcinoma (United States). 1202 Jan 11

Conjugated linoleic acid (CLA) is a group of polyunsaturated fatty acids found in beef, lamb, and dairy products that exist as positional and stereo-isomers of octadecadienoate (18:2). Over the past two decades numerous health benefits have been attributed to CLA in experimental animal models including actions to reduce carcinogenesis, atherosclerosis, onset of diabetes, and body fat mass. The accumulation of CLA isomers and several elongated/desaturated and beta-oxidation metabolites have been found in tissues of animals fed diets with CLA. Molecular mechanisms of action appear to include modulation of eicosanoid formation as well as regulation of the expression of genes coding for enzymes known to modulate macronutrient metabolism. This review focuses on health benefits, metabolism, and potential mechanisms of action of CLA and postulates the implications regarding dietary CLA for human health.
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PMID:Dietary conjugated linoleic acid in health: physiological effects and mechanisms of action. 1205 56

In the present study, the chemopreventive effect of the active metabolite of vitamin D, 1alpha,25-dihydroxyvitamin D(3) (VD(3)), against chemically-induced and diabetes-promoted rat liver carcinogenesis was investigated. Hepatocarcinogenesis was initiated with a single intraperitoneal (i.p.) injection of diethylnitrosamine (DEN) (125 mg kg(-1) body weight) at week 4 followed by promotion with streptozotocin (STZ) (65 mg kg(-1) body weight with a single i.p. injection) at week 7. With this basic experimental regimen, the effect of VD(3) (0.3 microg (0.1 ml)(-1) propylene glycol per os twice a week) was investigated with effect from 4 weeks prior to the exposure of DEN. The results showed that VD(3) supplementation throughout the experimental period reduced the incidence, total number and multiplicity and altered the size of visible persistent nodules (PNs) in DEN- or DEN + STZ-treated rats as compared with their respective controls. In these two groups, it also caused a significant decrease in the number (p < 0.002 and 0.001 respectively) and focal area (p < 0.05) of gamma-glutamyltranspeptidase (GGT)-positive hepatic foci. Moreover, continuous supplementation of VD(3) exhibits a protective effect in maintaining the normal cellular architecture of the hepatocytes in DEN- or DEN + STZ-treated rats. Our results thus strongly suggest that VD(3) is very effective in the inhibition of DEN-initiated and STZ-induced diabetes-promoted rat liver carcinogenesis.
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PMID:1alpha,25-Dihydroxyvitamin D(3) inhibits rat liver ultrastructural changes and the development of gamma-glutamyltranspeptidase-positive foci in diethylnitrosamine-initiated and streptozotocin-induced diabetes-promoted hepatocarcinogenesis. 1212 95

Several experimental studies suggest that disturbed methylation can influence cellular differentiation in the pancreas and contribute to toxic injury in ways that enhance the pathogenesis of pancreatitis and carcinogenesis. In vitro development of fetal rat pancreas requires a basal level of methionine, but full differentiation requires a higher methionine level. Involvement of methylation in normal differentiation is supported by reports of development of hepatocyte-like cells in the pancreas of rats fed a choline-deficient diet. The administration of ethionine by feeding to mice in a choline-sufficient diet caused a lower incidence of acute hemorrhagic pancreatitis than in mice given a choline-deficient diet. Feeding or injections of ethionine in choline-sufficient diets induces low grade pancreatitis and pancreatic atrophy in rats. In the N-nitrosobis(2-oxopropyl)amine-induced model of ductal adenocarcinoma in hamsters, the latent period for induction of carcinomas has been dramatically reduced by the intermittent feeding of a choline-deficient diet combined with ethionine treatment. A recent epidemiologic study in smokers indicates that the risk of pancreatic carcinoma is inverse to serum levels of folate. These studies suggest that compromised methyl metabolism might be associated with pancreatic cancer risk in humans. Finally, it has recently been demonstrated that serum homocysteine and erythrocyte S-adenosylhomocysteine levels are elevated, and erythrocyte S-adenosylmethionine content is reduced in patients with diabetes mellitus and renal failure, likely reflecting disturbed methylation pathways. The latter may contribute to the pathogenesis of complicating lesions in diabetes. These studies suggest that disturbed methyl metabolism may contribute to the pathogenesis of several pancreatic diseases.
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PMID:Abnormal methyl metabolism in pancreatic toxicity and diabetes. 1216 95

Chronic infection with hepatitis C virus (HCV) is a major risk factor for development of hepatocellular carcinoma (HCC). In general, HCC develops only after 2 or more decades of HCV infection and the increased risk is restricted largely to patients with cirrhosis or advanced fibrosis. Factors that predispose to HCC among HCV-infected persons include male sex, older age, hepatitis B virus (HBV) coinfection, heavy alcohol intake, and possibly diabetes and a transfusion-related source of HCV infection. Viral factors play a minor role. The likelihood of development of HCC among HCV-infected persons is difficult to determine because of the paucity of adequate long-term cohort studies; the best estimate is 1% to 3% after 30 years. Once cirrhosis is established, however, HCC develops at an annual rate of 1% to 4%. Successful antiviral therapy of patients with HCV-related cirrhosis may reduce the future risk for HCC. The incidence of and mortality caused by all HCC has doubled in the United States over the past 25 years, an increase that has affected all ethnic groups, both sexes, and younger age groups. Given the current prevalence of HCV infection among persons 30 to 50 years of age, the incidence and mortality rates of HCC are likely to double in the United States over the next 10 to 20 years. Future research should focus on improving understanding of the incidence and risk factors for HCC, causes of HCV-related carcinogenesis, means of early detection, and better treatment for HCC.
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PMID:Hepatocellular carcinoma and hepatitis C in the United States. 1240 79

Reactive carbonyl species (RCS) are potent mediators of cellular carbonyl stress originating from endogenous chemical processes such as lipid peroxidation and glycation. Skin deterioration as observed in photoaging and diabetes has been linked to accumulative protein damage from glycation, but the effects of carbonyl stress on skin cell genomic integrity are ill defined. In this study, the genotoxic effects of acute carbonyl stress on HaCaT keratinocytes and CF3 fibroblasts were assessed. Administration of the alpha-dicarbonyl compounds glyoxal and methylglyoxal as physiologically relevant RCS inhibited skin cell proliferation, led to intra-cellular protein glycation as evidenced by the accumulation of N(epsilon)-(carboxymethyl)-L-lysine (CML) in histones, and caused extensive DNA strand cleavage as assessed by the comet assay. These effects were prevented by treatment with the carbonyl scavenger D-penicillamine. Both glyoxal and methylglyoxal damaged DNA in intact cells. Glyoxal caused DNA strand breaks while methylglyoxal produced extensive DNA-protein cross-linking as evidenced by pronounced nuclear condensation and total suppression of comet formation. Glycation by glyoxal and methylglyoxal resulted in histone cross-linking in vitro and induced oxygen-dependent cleavage of plasmid DNA, which was partly suppressed by the hydroxyl scavenger mannitol. We suggest that a chemical mechanism of cellular DNA damage by carbonyl stress occurs in which histone glycoxidation is followed by reactive oxygen induced DNA stand breaks. The genotoxic potential of RCS in cultured skin cells and its suppression by a carbonyl scavenger as described in this study have implications for skin damage and carcinogenesis and its prevention by agents selective for carbonyl stress.
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PMID:DNA damage by carbonyl stress in human skin cells. 1251 11

The mechanisms of interaction and cross-impact of metabolic processes in a combined diabetes and cancer condition are discussed. A hypothesis is proposed whereby the processes responsible for destruction of the organism in the case of diabetes--long-term hyperglycemia and generation of methylglyoxal--may substantially impact tumor development. The hypothesis is based on the fact that both diabetes and carcinogenesis cause dysfunction of the vital cellular signal system regulated by the protein kinase C (PKC) family. Normalization of the PKC functional activity in the case of diabetes restrains development of diabetic complications and inhibits the processes of tumor growth and metastasizing in carcinogenesis. On this basis, an attempt is made to interpret both the detrimental and beneficial effects of diabetes on cancer. The resultant effect is determined by the type of tumor and the duration and level of hyperglycemia. The mechanisms of the impact of diabetes mellitus on cancer are analyzed to develop recommendations for combined cancer therapy options.
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PMID:Molecular mechanisms of the cross-impact of pathological processes in combined diabetes and cancer. Research and clinical aspects. 1294 66

The aim of this study was to compare mammary gland tumorigenesis in diabetic and non-diabetic rats. Streptozotocin and N-nitroso-N-methylurea were used to induce diabetes and mammary tumors, respectively. A suppression of mammary carcinogenesis in diabetic rats was shown by a longer latency period, a lower number of tumors per animal and a smaller final tumor volume. An 84% of the lesions developed in diabetic animals were benign tumors. Eighty day-old diabetic rats had significantly lower plasma levels of total-IGF-I and insulin versus non-diabetic rats. We postulate that the decrease in the total IGF-I and insulin levels during the promotion phase of carcinogenesis in this model plays an important role in retarding the tumor development in diabetic animals and in favoring the development of benign mammary lesions.
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PMID:Suppression of mammary gland tumorigenesis in diabetic rats. 1260 Apr 16

Adrenomedullin (AM) is a pluripotent hormone with structural similarities to calcitonin gene-related peptide (CGRP), which is expressed by many tissues in the body and shows a remarkable range of effects mediated by paracrine/autocrine and possibly endocrine mechanisms. AM has been implicated as a mediator of several pathologies such as cardiovascular and renal disorders, sepsis, inflammation, diabetes and cancer, among others. AM is expressed in a variety of tumors where it aggravates several of the molecular and physiological features of malignant cells. AM has been shown to be a mitogenic factor stimulating growth in several cancer types and to encourage a more aggressive tumor phenotype. In addition, AM is an apoptosis survival factor for cancer cells and an indirect suppressor of the immune response through its binding protein, complement factor H, and regulation in expression of cytokines. AM plays an important role in environments subjected to low oxygen tensions, which is a typical feature in the proximity of solid tumors. Under these conditions, AM is upregulated through a hypoxia-inducible factor 1 (HIF-1)-dependent pathway and acts as a potent angiogenic factor promoting neovascularization. The collective findings brought together over the last years place AM as a major regulator of carcinogenesis-tumor progression and identifies its autocrine loop as a putative target for developing new strategies against human cancers.
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PMID:Adrenomedullin and cancer. 1266 40

Estrogen is involved in breast carcinogenesis. Hypotheses have been raised that its effect is modified by enzymes such as catechol-O-methyltransferase (COMT) that deactivate potentially genotoxic estrogen metabolites. We have investigated the association between the functional genetic Val108/158Met polymorphism in COMT and breast cancer risk in a large population-based case-control study performed in the genetically homogeneous Swedish population. We determined COMT genotype in 1534 women with invasive breast cancer and in 1504 control women and calculated odds ratios (OR) and 95% confidence intervals (CI) from logistic regression models. There was no overall association between COMT genotype and breast cancer risk. However, the L allele was associated with an increased risk for lobular breast cancer, with OR 2.0 (95% CI 1.2-3.5) for HL and 1.7 (95% CI 0.9-3.0) for LL. In exploratory subset analyses, we found no statistically significant interaction, but some indication of a positive association between HL and LL genotypes and breast cancer among women with diabetes mellitus and a negative association among nulliparous women. Based on our findings, COMT activity alone does not seem to play a major role in breast carcinogenesis, but may be of importance in certain histotypes or in conjunction with other exposures.
Carcinogenesis 2003 Apr
PMID:Catechol-O-methyltransferase gene polymorphism and post-menopausal breast cancer risk. 1272 96


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