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1.
Acta Diabetol ; 2024 May 26.
Artigo em Inglês | MEDLINE | ID: mdl-38796828

RESUMO

INTRODUCTION: Type 1 and type 2 diabetes mellitus (DM) are often accompanied by mild forms of pancreatic exocrine insufficiency (PEI). The prevalence rates of PEI in diabetic patients are unclear and variable depending on the testing modality and the studies published. The clinical consequences of PEI in diabetics are also not well defined. AIM: We aimed to determine the prevalence of PEI in a diabetic cohort using the faecal elastase-1 (FE-1) assay as a screening test and to validate a patient-reported symptom-based scoring system, the (PEI-S) for diagnosing PEI within this patient population. METHODS: Two hundred and three diabetic patients attending diabetic and gastroenterology outpatients of a university hospital without previously known PEI were recruited for the study. Demographic parameters, PEI score (PEI-S), and glycated hemoglobin (HBA1c) were documented in standardized data sheets, and a stool sample was obtained. A FE-1 value < 200 µg/g and or a PEIS of > 0.6 was used as the screening cut-off for PEI. RESULTS: One hundred sixty-six patients returned faecal samples. The prevalence of PEI, as measured by low FE-1, was 12%. Smoking was associated with an increased risk of developing PEI in this diabetic population. No other independent risk factors were identified. The PEI-S system did not differentiate between people with diabetes having a normal and low FE1. CONCLUSION: 12% of this mixed, real-life cohort of type 1 and 2 DM patients had undiagnosed PEI, as defined by an FE-1 score of less than 200 µg/g. While this may appear low, given the rising prevalence of type 2 DM worldwide, there is likely an unrecognized burden of PEI, which has long-term health consequences for those affected. The PEI-S, a symptom-scoring system for patients with PEI, did not perform well in this patient group.

2.
Digestion ; 95(4): 288-292, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28511171

RESUMO

INTRODUCTION: The finding of a raised intraepithelial lymphocytes (IELs) count with normal villous architecture is of sufficient clinical importance to be reported in routine duodenal biopsies. AIM: To study the clinical and demographic data of patients with isolated increased IELs on duodenal biopsy. METHODS: A single-tertiary-centre retrospective study was carried out with a review of medical records of patients with increased IELs. Patients from 2012 to 2014, >18 years with at least one biopsy from the second part of the duodenum with increased IELs; defined as >25 IELs/100 enterocytes, with preserved villous architecture were identified from our histopathology database with exclusion of patients with coeliac disease (CD).Clinical and demographic data were recorded following a chart review. CD was diagnosed by the attending physician based on the Physician Global Assessment. Data was compared between groups using a Student t test and ORs were calculated as appropriate. Statistical significance was set a priori at p < 0.05. RESULTS: Over 24 months, 6,244 patients were found to have duodenal biopsies and 114 (1.8%) had isolated increased IELs. Of the patients with increased IELs, the mean age was 50 years and 34 (30%) were male. Follow-up was available in 75 (65%) of these and CD was subsequently diagnosed in 32% (n = 24). CD was associated with the female gender (22 out of 24 vs. 39 out of 51, OR 7.5, older age 55 vs. 41 years, p < 0.04), and higher IEL count with an IEL of >40 in 11 out of 24 (46%) with CD vs. 12 out of 51 (24%) without CD, p = 0.0006. CONCLUSION: It is a non-specific but important finding, as it can have clinical implications.


Assuntos
Doença Celíaca/imunologia , Duodeno/imunologia , Linfócitos Intraepiteliais , Adulto , Idoso , Idoso de 80 Anos ou mais , Biópsia , Duodeno/patologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Adulto Jovem
4.
Aliment Pharmacol Ther ; 33(12): 1261-72, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21521250

RESUMO

BACKGROUND: Patients with inflammatory bowel disease (IBD) are at increased risk of osteoporosis. A number of studies have emerged in recent years indicating that tumour necrosis factor (TNF) blockade appears to have a beneficial effect on bone mineral density (BMD) in IBD patients. AIMS: To provide a review of the available data regarding the effect of the currently licensed anti-TNF-α therapies on bone metabolism and BMD in IBD patients. METHODS: A Medline search was performed using the search terms 'infliximab', 'bone metabolism', 'IBD', 'BMD', 'bone markers', 'adalimumab', 'bone disease', 'Crohn's disease' and 'ulcerative colitis'. RESULTS: Infliximab has a beneficial effect on bone turnover markers in Crohn's disease (CD) patients in the short term. The longest study to date comprising 24 CD patients showed an overall improvement in two bone formation markers - b-alkaline phosphatase (P = 0.022) and osteocalcin (P = 0.008) at 4 months post-treatment. Moreover, the largest study to date comprising 71 CD patients showed significant improvement in sCTx, a bone resorption marker (P = 0.04) at week-8 post-treatment. There is little data looking at the effect of anti-TNF-α therapy on bone metabolism in ulcerative colitis. Moreover, the long-term effects of anti-TNF-α therapy on bone structure and fracture risk in IBD patients are currently not known. The effect of cessation of anti-TNF-α therapy on bone metabolism is also unknown. CONCLUSION: Properly controlled long-term trials are needed to fully evaluate the impact of TNF blockade on bone mineral density.


Assuntos
Corticosteroides/efeitos adversos , Anticorpos Monoclonais/uso terapêutico , Densidade Óssea/efeitos dos fármacos , Fraturas Ósseas/prevenção & controle , Doenças Inflamatórias Intestinais/tratamento farmacológico , Osteoporose/tratamento farmacológico , Fator de Necrose Tumoral alfa/uso terapêutico , Anticorpos Monoclonais/farmacologia , Feminino , Fraturas Ósseas/induzido quimicamente , Humanos , Doenças Inflamatórias Intestinais/complicações , Doenças Inflamatórias Intestinais/metabolismo , Infliximab , Masculino , Osteoporose/induzido quimicamente , Fator de Necrose Tumoral alfa/farmacologia
5.
J Crohns Colitis ; 3(4): 282-6, 2009 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21172288

RESUMO

UNLABELLED: Video capsule endoscopy is an invaluable tool for examining the small bowel. It is non-invasive and generally well tolerated, however its role in the assessment of the severity and extent of small bowel Crohn's disease has not, to date, been adequately evaluated. METHODS: All capsule endoscopies performed over a two year period in a tertiary referral centre in subjects with known or suspected Crohn's disease were reviewed. RESULTS: Twenty-six capsule endoscopy studies in total were included. These were performed in 15 cases of known Crohn's disease, 5 cases of suspected Crohn's disease, 3 cases of endoscopically diagnosed non-specific terminal ileal inflammation and finally 3 post colectomy cases of indeterminant being considered for IPAA formation. Ten patients known to have small bowel Crohn's disease were prospectively recruited; of 3 with normal small bowel follow through or CT exams, one had an abnormal capsule endoscopy. The other 7 patients had small bowel follow through or abdominal CT scans consistent with small bowel Crohn's disease; additional mucosal abnormalities were detected by capsule endoscopy in 6 cases with capsule retention in the stomach in one. Of 5 with colonic Crohn's disease normal small bowel imaging corresponded with normal capsule endoscopy in all but one. A diagnosis of Crohn's disease was made in 2 out of 5 cases of suspected Crohn's disease on the basis of the capsule endoscopy findings. Three patients with non-specific acute terminal ileal inflammation at ileocolonoscopy were confirmed to have ongoing inflammation. The capsule was retained in four subjects beyond 24 h. CONCLUSION: Capsule endoscopy more accurately determines the severity and extent of the Crohn's disease in the small bowel than traditional imaging modalities.

6.
Ann Oncol ; 19(6): 1075-81, 2008 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-18238782

RESUMO

ADAM-17 is a matrix metalloproteinase-like enzyme involved in the release of several ligands that have been shown to promote both cancer formation and progression. These ligands include transforming growth factor-alpha, amphiregulin, heparin-binding epidermal growth factor, epiregulin and tumor necrosis factor-alpha. In this investigation, we measured the expression of total ADAM-17 by enzyme-linked immunosorbent assay in 153 invasive breast cancers. We also measured the precursor and active forms by western blotting in 140 invasive breast cancers. Expression of ADAM-17 was significantly increased in high-grade compared with low-grade tumors and was independent of tumor size, lymph node metastasis and estrogen receptor status. Patients with high expression of ADAM-17 had a significantly shorter overall survival compared with those with low expression. Significantly, the prognostic impact of ADAM-17 was independent of conventional prognostic factors for breast cancer. Our results are further evidence that ADAM-17 is involved in breast cancer progression and thus provides further impetus for exploiting ADAM-17 as new target for cancer treatment.


Assuntos
Proteínas ADAM/biossíntese , Neoplasias da Mama/enzimologia , Proteína ADAM17 , Neoplasias da Mama/mortalidade , Progressão da Doença , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Pessoa de Meia-Idade , Prognóstico
7.
Ann Oncol ; 17(4): 597-604, 2006 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-16403812

RESUMO

BACKGROUND: Survivin, a novel inhibitor of apoptosis, is one of the most cancer-specific proteins identified to date. In this study we (a) evaluated the association between survivin and HER2, vascular endothelial growth factor (VEGF) and uPA/PAI-1 expression and (b) defined its effect on clinical outcome in a large breast cancer patient cohort. PATIENTS AND METHODS: Survivin expression was measured by ELISA in primary breast cancer tissue extracts from 420 patients with long-term clinical follow-up. RESULTS: Survivin was detected in 378 (90%) of the 420 primary breast cancer cases. Increased survivin levels were significantly associated with high nuclear grade (P < 0.0001), negative hormone receptor status (P = 0.0028), HER2 overexpression (P = 0.0094), VEGF expression (P < 0.0001), high uPA (P = 0.0002) and PAI-1 levels (P = 0.0002). Using the 25th percentile (1.4 ng/mg) as a cut-off point, patients expressing elevated survivin had a significantly worse disease-free survival (DFS: P = 0.0007, RR 1.97) and overall survival (OS: P = 0.0009, RR 2.11) compared with patients expressing lower levels of survivin. In multivariate analysis, this prognostic value of survivin was independent of both traditional and novel clinicopathologic factors for both DFS (P = 0.0076, RR 1.72) and OS (P = 0.0155, RR 1.76). CONCLUSIONS: The independent prognostic relevance of survivin, when combined with previous data from model systems implicating survivin in the inhibition of apoptosis, suggests that survivin may be a suitable target for future therapeutic strategies.


Assuntos
Neoplasias da Mama/metabolismo , Proteínas Associadas aos Microtúbulos/metabolismo , Proteínas de Neoplasias/metabolismo , Inibidor 1 de Ativador de Plasminogênio/metabolismo , Receptor ErbB-2/metabolismo , Resultado do Tratamento , Ativador de Plasminogênio Tipo Uroquinase/metabolismo , Fator A de Crescimento do Endotélio Vascular/metabolismo , Estudos de Coortes , Feminino , Humanos , Proteínas Inibidoras de Apoptose , Survivina
8.
Eur J Gastroenterol Hepatol ; 17(4): 463-6, 2005 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-15756102

RESUMO

We describe a patient with chylous ascites, who was extensively investigated for the cause. No malignant or lymphatic disease could be found, but a liver biopsy revealed liver cirrhosis. The chylous ascites was unsuccessfully treated with a sodium restriction diet, diuretics and a medium chain triglyceride diet. After the placement of a transjugular intrahepatic portosystemic shunt the ascites disappeared.


Assuntos
Ascite Quilosa/cirurgia , Cirrose Hepática/cirurgia , Derivação Portossistêmica Transjugular Intra-Hepática , Idoso , Ascite Quilosa/etiologia , Ascite Quilosa/patologia , Humanos , Fígado/patologia , Cirrose Hepática/complicações , Cirrose Hepática/patologia , Masculino , Triglicerídeos/análise , Triglicerídeos/sangue
9.
Aliment Pharmacol Ther ; 20(8): 851-7, 2004 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-15479356

RESUMO

BACKGROUND AND AIMS: Patients with Crohn's disease are at increased risk of osteoporosis. Disease activity and circulating proinflammatory cytokines are thought to play a role in this process. Infliximab, a chimaeric antitumour necrosis factor-alpha antibody is effective in the treatment of Crohn's disease. The aim of this study was to investigate the impact of treatment with infliximab on bone turnover in Crohn's disease patients. METHODS: This was a prospective trial. Twenty-four patients with active Crohn's disease were treated with infliximab (5 mg/kg). Bone markers were assayed pre- and post-treatment. Bone formation was measured using serum bone-specific alkaline phosphatase and total osteocalcin and bone resorption using serum N-telopeptide cross-linked type 1 collagen. RESULTS: Infliximab therapy caused a significant increase in both markers of bone formation in patients with active Crohn's disease. No significant change in the bone resorption marker serum N-telopeptide cross-linked type 1 was found. CONCLUSION: Infliximab therapy had a significant beneficial effect on bone metabolism in patients with active Crohn's disease. These findings further support the theory that active ongoing inflammation and high levels of circulating cytokines play a pivotal role in the pathogenesis of bone loss in patients with Crohn's disease.


Assuntos
Anticorpos Monoclonais/efeitos adversos , Remodelação Óssea/efeitos dos fármacos , Doença de Crohn/tratamento farmacológico , Fármacos Gastrointestinais/efeitos adversos , Adulto , Idoso , Biomarcadores/sangue , Feminino , Humanos , Infliximab , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos
10.
Am J Gastroenterol ; 98(8): 1682-7, 2003 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-12907319

RESUMO

Inflammatory bowel disease (IBD) is associated with an increased risk of developing intestinal cancer at sites of chronic inflammation. Aminosalicylates, including both sulfasalazine and mesalamine, are the most commonly prescribed anti-inflammatory agents prescribed in IBD. On balance, the body of literature to date suggests that aminosalicylates confer some protection against the development of colonic neoplasia in patients with IBD and in a variety of models, including in the noninflamed gut. This latter observation implies that aminosalicylates may be of chemopreventive value in normal as well as IBD individuals. The current review examines and gives an overview of the evidence from a variety of sources, including epidemiological, in vivo and in vitro studies that have investigated the potential anticancer effects of aminosalicylates.


Assuntos
Ácidos Aminossalicílicos/uso terapêutico , Anti-Inflamatórios não Esteroides/uso terapêutico , Anticarcinógenos/uso terapêutico , Neoplasias Colorretais/prevenção & controle , Doenças Inflamatórias Intestinais/tratamento farmacológico , Animais , Neoplasias Colorretais/etiologia , Estudos de Avaliação como Assunto , Humanos , Doenças Inflamatórias Intestinais/complicações
12.
Gut ; 52(3): 358-62, 2003 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-12584216

RESUMO

BACKGROUND AND AIMS: The majority of patients with inflammatory bowel disease (IBD) have a normal life expectancy and therefore should not be weighted when applying for life assurance. There is scant literature on this topic. In this study our aim was to document and compare the incidence of difficulties in application for life and medical insurance in a population based cohort of IBD patients and matched population controls. METHODS: A population based case control study of 1126 IBD patients and 1723 controls. Based on a detailed questionnaire, the frequency and type of difficulties encountered when applying for life and medical insurance in matched IBD and control populations were appraised. RESULTS: In comparison with controls, IBD patients had an 87-fold increased risk of encountering difficulties when applying for life assurance (odds ratio (OR) 87 (95% confidence interval (CI) 31-246)), with a heavily weighted premium being the most common problem. Patients of high educational status, with continuous disease activity, and who smoked had the highest odds of encountering such problems. Medical insurance difficulties were fivefold more common in IBD patients compared with controls (OR 5.4 (95% CI 2.3-13)) although no specific disease or patient characteristics were identified as associated with such difficulties. CONCLUSIONS: This is the first detailed case control study that has investigated insurance difficulties among IBD patients. Acquiring life and medical insurance constituted a major problem for IBD patients in this study. These results are likely to be more widely representative given that most insurance companies use international guidelines for risk assessment. In view of the recent advances in therapy and promising survival data on IBD patients, evidence based guidelines for risk assessment of IBD patients by insurance companies should be drawn up to prevent possible discriminatory practices.


Assuntos
Doenças Inflamatórias Intestinais/economia , Doenças Inflamatórias Intestinais/reabilitação , Cobertura do Seguro/estatística & dados numéricos , Seleção Tendenciosa de Seguro , Seguro Saúde/estatística & dados numéricos , Seguro de Vida/estatística & dados numéricos , Sistema de Registros , Adolescente , Adulto , Estudos de Casos e Controles , Escolaridade , Feminino , Humanos , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Países Baixos , Razão de Chances , Preconceito , Prognóstico , Fatores de Risco , Fumar
13.
Gut ; 52(1): 101-8, 2003 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-12477769

RESUMO

BACKGROUND AND AIMS: Mutant tumour derived DNA has been detected in the sera of colorectal cancer patients. We investigated if mutant serum KRAS2 was detectable preoperatively in a large group of patients with colorectal neoplasia. A prospective study of 94 patients who underwent putative curative resection for colorectal carcinoma (CRC) was performed to ascertain if serum mutant KRAS2 could be used postoperatively as a disease marker. METHODS: Preoperative sera from 78 patients were analysed (group A). Sera from 94 patients were obtained three monthly for up to three years during the postoperative period (group B). Codon 12 and 13 KRAS2 mutations were analysed in matched tumour and serum samples. RESULTS: In the preoperative group (group A), KRAS2 mutation was found in 41/78 (53%) tumours and in 32/78 (41%) preoperative sera. Of 41 tumour KRAS2 mutation positive cases, 31/41 (76%) had an identical serum mutation detectable. In group B, the postoperative follow up group, 60/94 cases were primary tumour KRAS2 mutation positive. Of these 60, 16/60 (27%) became persistently serum mutant KRAS2 positive postoperatively. Ten of 16 (63%) of these developed a recurrence compared with only 1/44 (2%) patients who remained serum mutant negative (odds ratio 71.7 (95% confidence interval 7.7-663.9; p=0.0000). None of 34 tumour mutation negative cases became serum mutant KRAS2 positive postoperatively, despite recurrence in 9/34 patients. The relative hazard of disease recurrence in postoperative serum mutant KRAS2 positive patients was 6.37 (2.26-18.0; p=0.000). CONCLUSIONS: Serum mutant KRAS2 can be detected preoperatively in all stages of colorectal neoplasia. Postoperatively, serum mutant KRAS2 is a strong predictor of disease recurrence, stronger even than Dukes' stage of disease, and thus shows potential for use in clinical practice as a marker of preclinical disease recurrence.


Assuntos
Neoplasias Colorretais/sangue , Neoplasias Colorretais/genética , DNA de Neoplasias/sangue , Recidiva Local de Neoplasia/sangue , Proteínas Proto-Oncogênicas/sangue , Proteínas Proto-Oncogênicas/genética , Idoso , Biomarcadores/sangue , Antígeno Carcinoembrionário/sangue , Neoplasias Colorretais/mortalidade , Análise Mutacional de DNA , Estudos Epidemiológicos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico , Proteínas Proto-Oncogênicas p21(ras) , Proteínas ras
14.
Eur J Clin Microbiol Infect Dis ; 21(1): 27-34, 2002 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-11913498

RESUMO

The bactericidal activities and post-antibiotic effects of BMS-284756 (T-3811ME), levofloxacin, and ciprofloxacin were evaluated against a methicillin-susceptible and a methicillin-resistant Staphylococcus aureus strain. Minimum inhibitory concentrations (MICs), minimum bactericidal concentrations, post-antibiotic effects, and post-antibiotic sub-MIC effects were determined and time-kill studies were performed for BMS-284756, levofloxacin, and ciprofloxacin. At 4-times and 10-times the MIC, time-kill kinetics over 3 h and over 24 h were similar for all three quinolones when effects were considered as multiples of the MIC. All three quinolones achieved a 3 log10 reduction in cfu/ml within 2 h. At 10-times the MIC, the post-antibiotic effects of BMS-284756, levofloxacin, and ciprofloxacin were 1.6-2.6 h for the methicillin-susceptible Staphylococcus aureus strain and 1.5-1.9 h for the methicillin-resistant Staphylococcus aureus strain. When actual concentrations were considered, BMS-284756 achieved results comparable to levofloxacin and ciprofloxacin at concentrations nearly 10-fold less. When relating the pharmacokinetic properties of the three quinolones to their in vitro activities, the resulting Cmax/MIC and AUC/MIC ratios were. respectively, 120-240.7 and 1,321.7-2,643 for BMS-284756, 22.8 and 190 for levofloxacin, and 5.9-11.9 and 54.8-109.6 for ciprofloxacin. The greater in vitro activity and favorable human pharmacokinetics of BMS-284756 may translate to improved clinical effectiveness of this agent compared to currently marketed quinolones.


Assuntos
Anti-Infecciosos/farmacologia , Ciprofloxacina/farmacologia , Fluoroquinolonas , Indóis , Levofloxacino , Resistência a Meticilina , Ofloxacino/farmacologia , Quinolonas , Staphylococcus aureus/efeitos dos fármacos , Atividade Bactericida do Sangue , Resistência Microbiana a Medicamentos , Humanos , Meticilina/farmacologia , Testes de Sensibilidade Microbiana , Sensibilidade e Especificidade
15.
Br J Cancer ; 85(10): 1499-503, 2001 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-11720435

RESUMO

The incidence of oesophageal adenocarcinoma is rising; to date, no susceptibility genes have been identified. p73, a novel p53 homologue, maps to chromosome 1p36, a region commonly deleted in oesophageal cancers. p73 shares some p53-like activity, but in addition, may also play a role in gastrointestinal epithelial inflammatory responses. A non-coding p73 polymorphism (denoted AT or GC) may be functionally significant. We investigated whether this polymorphism might play a role in the aetiopathogenesis of oesophageal cancer. This was a case-control, retrospective study. 84 cases of oesophageal cancer (25 squamous and 59 adenocarcinoma) and 152 normal population controls were genotyped for this polymorphism. Informative cases were examined for p73 LOH within the tumour. AT/AT homozygotes were significantly less prevalent in the oesophageal cancer population (1/84 = 1.2%) compared to controls (15/152 = 9.9%) (P < 0.02), corresponding to an odds ratio of 0.11 (95% C.I. 0.02-0.6, P < 0.02), or 9-fold reduced risk. Moreover, AT/AT homozygotes were significantly less frequent in the cancer population than would be expected under the Hardy-Weinberg hypothesis (P = 0.0099). LOH at the p73 locus was observed in 37.8% (14/37) of the AT/GC heterozygotes studied; in all cases there was loss of the AT allele. Our findings indicate that p73 AT/AT homozygotes appear to be protected against the development of oesophageal cancer. Clinically, this observation could have implications in aiding identification of high-risk Barrett's oesophagus patients.


Assuntos
Carcinoma/genética , Proteínas de Ligação a DNA/genética , Neoplasias Esofágicas/genética , Predisposição Genética para Doença , Proteínas Nucleares/genética , Polimorfismo Genético , Adenocarcinoma/epidemiologia , Adenocarcinoma/genética , Adulto , Idoso , Carcinoma/epidemiologia , Carcinoma de Células Escamosas/epidemiologia , Carcinoma de Células Escamosas/genética , Estudos de Casos e Controles , Neoplasias Esofágicas/epidemiologia , Feminino , Frequência do Gene , Genes Supressores de Tumor , Genótipo , Humanos , Incidência , Perda de Heterozigosidade , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Proteína Tumoral p73 , Proteínas Supressoras de Tumor
16.
J Lab Clin Med ; 138(3): 164-76, 2001 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-11528369

RESUMO

The purpose of this review is to outline the principal mechanisms involved in folate metabolism and how they may relate to the pathogenesis of colorectal cancer (CRC). In recent years, mild folate depletion (low normal level) has been associated with an increased risk of developing certain cancers, in particular colorectal neoplasia. The epidemiologic and mechanistic evidence linking folate deficiency with carcinogenesis is reviewed, with a particular emphasis on colorectal neoplasia. Methylenetetrahydrofolate reductase (MTHFR) is a critical folate metabolizing enzyme, and a functional polymorphic variant of this enzyme, the so-called thermolabile variant, caused by a C677T transition in the MTHFR gene, is common in the general population. This review critically examines the evidence that suggests that carriers of this C677T variant may be at increased risk of developing colorectal neoplasia. Although folate depletion may predispose to the initiation of the neoplastic process, folate supplementation, on the other hand, might potentiate the progression of an already established early neoplastic clone (eg, a colorectal adenoma). This could have potential public health implications, given an increasingly widespread policy of folate supplementation of food staples.


Assuntos
Adenoma/metabolismo , Neoplasias Colorretais/metabolismo , Ácido Fólico/metabolismo , Vitamina B 12/metabolismo , Adenoma/genética , Adenoma/patologia , Animais , Neoplasias Colorretais/genética , Neoplasias Colorretais/patologia , Metilação de DNA , DNA de Neoplasias/biossíntese , Suplementos Nutricionais/efeitos adversos , Ácido Fólico/administração & dosagem , Deficiência de Ácido Fólico/metabolismo , Humanos , Metilenotetra-Hidrofolato Redutase (NADPH2) , Oxirredutases atuantes sobre Doadores de Grupo CH-NH/genética , Oxirredutases atuantes sobre Doadores de Grupo CH-NH/metabolismo
17.
Int J Toxicol ; 20(3): 121-42, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11488554

RESUMO

This study evaluated the potential reproductive toxicity of phenol in a rat two-generation reproduction study, which included additional study endpoints, such as sperm count and motility, developmental landmarks, histological evaluation of suspect target organs (liver, kidneys, spleen, and thymus), weanling reproductive organ weights, and an immunotoxicity screening plaque assay. Phenol was administered to 30 Sprague-Dawley rats/sex/group in the drinking water at concentrations of 0, 200, 1000, or 5000 ppm. Parental (P1) animals were treated for 10 weeks prior to mating, during mating, gestation, lactation, and until sacrifice. The F1 generation (P1 offspring) was treated using a similar regimen, while the F2 generation was not treated. After mating, 10 P1 males/group were evaluated using standard clinical pathology parameters and an immunotoxicity screening plaque assay. Significant reductions in water and food consumption were observed in the 5000-ppm group in both generations; corollary reductions in body weight/body weight gain were also observed. Mating performance and fertility in both generations were similar to controls, and no adverse effects on vaginal cytology or male reproductive function were observed. Vaginal opening and preputial separation were delayed in the 5000-ppm group, and were considered to be secondary to the reduction in F1 body weight. Litter survival of both generations was reduced in the 5000-ppm group. Absolute uterus and prostate weights were decreased in the F1 generation at all dose levels; however, no underlying pathology was observed and there was no functional deficit in reproductive performance. Therefore, these findings were not considered to be adverse. No evidence of immunotoxicity was noted in the 5000-ppm group. The effects noted at the high concentration were presumed to be associated with flavor aversion to phenol in the drinking water. Based on a comprehensive examination of all parameters, the no-observable-adverse-effect level (NOAEL) for reproductive toxicity of phenol administered in drinking water to rats is 1000 ppm. The corresponding daily intake of phenol for an adult rat at the NOAEL of 1000 ppm is equivalent to about 70 mg/kg/day for males and 93 mg/kg/day for females.


Assuntos
Desinfetantes/toxicidade , Genitália/anormalidades , Fenol/toxicidade , Efeitos Tardios da Exposição Pré-Natal , Reprodução/efeitos dos fármacos , Administração Oral , Animais , Peso Corporal , Desinfetantes/administração & dosagem , Ingestão de Alimentos/efeitos dos fármacos , Feminino , Masculino , Nível de Efeito Adverso não Observado , Fenol/administração & dosagem , Gravidez , Ratos , Ratos Sprague-Dawley , Abastecimento de Água
19.
Expert Opin Investig Drugs ; 10(8): 1409-22, 2001 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-11772259

RESUMO

Efflux is the process in which bacteria transport compounds outside the cell which are potentially toxic, such as drugs or chemicals or compounds. Efflux pumps can be identified not only by biochemical, microbiological, or molecular means but with the availability of microbial genomic sequences, by the application of bioinformatics analysis of DNA sequences for key conserved structure motifs. Efflux has been identified as a relevant contributor to bacterial resistance in the clinic and is now recognised as one of the most important causes of intrinsic antibiotic resistance in bacteria, especially in Pseudomonas aeruginosa. With the recognition of efflux as a major factor in bacterial resistance, several companies have invested in the identification and development of bacterial efflux pump inhibitors. Among those, Microcide, Pfizer, Paratek and several academic laboratories are in the process of exploring efflux pump inhibitors from synthetic, natural products and peptidomimetics. Inhibiting bacterial efflux with a non-antibiotic inhibitor would restore activity of an antibiotic subject to efflux (similar to the use of beta-lactamase inhibitors to combat beta-lactamase production by bacteria). The feasibility of such an approach has been experimentally demonstrated in vitro and in vivo for efflux reversal of levofloxacin.


Assuntos
Bactérias/metabolismo , Toxinas Bacterianas/metabolismo , Bactérias/efeitos dos fármacos , Transporte Biológico Ativo/efeitos dos fármacos , Resistência a Medicamentos
20.
Int J Gastrointest Cancer ; 30(3): 105-11, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-12540022

RESUMO

BACKGROUND AND AIM: Folate deficiency predisposes to sporadic colorectal cancer (CRC). Methylenetetrahydrofolate reductase (MTHFR) is a critical folate-metabolising enzyme and a polymorphism at position 677 (C677T), is associated with reduced enzyme activity. We investigated whether this functional polymorphism modulates the risk of developing CRC. METHODS: This was a retrospective case-control study. 136 unselected cases of sporadic CRC and 848 normal population controls were genotyped for the MTHFR C677T polymorphism. Tumor tissue was genotyped to assess loss of heterozygosity (LOH). RESULTS: MTHFR CT heterozygotes had a significantly increased risk of developing CRC (53.7% of CRC cases vs 38.4% of controls), odds ratio 1.86 (95% CI 1.3-2.7, p < 0.005). No increased cancer risk was observed in TT homozygotes. The MTHFR 'T' allele frequency was significantly higher in the cancer group (0.3713) as compared to controls (0.2900, p < 0.008). LOH at the MTHFR locus was observed in 18% of informative cancers, with exclusive loss of the variant 'T' allele, in all cases. CONCLUSION: In this study of a homogenous northern European population, MTHFR CT heterozygotes had an almost two-fold increased risk of developing sporadic CRC. The exclusive pattern of MTHFR allele loss in cases of LOH, suggest that functional MTHFR activity within a tumor might play an important role in the survival and progression of a colonic neoplasm.


Assuntos
Adenocarcinoma/genética , Neoplasias Colorretais/genética , Oxirredutases atuantes sobre Doadores de Grupo CH-NH/genética , Adenocarcinoma/enzimologia , Estudos de Casos e Controles , Neoplasias Colorretais/enzimologia , Progressão da Doença , Humanos , Perda de Heterozigosidade , Metilenotetra-Hidrofolato Redutase (NADPH2) , Polimorfismo Genético/genética , Estudos Retrospectivos , Fatores de Risco
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