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1.
Molecules ; 27(13)2022 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-35807545

RESUMO

Coming into the second year of the pandemic, the acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its variants continue to be a serious health hazard globally. A surge in the omicron wave, despite the discovery of the vaccines, has shifted the attention of research towards the discovery and use of bioactive compounds, being potential inhibitors of the viral structural proteins. The present study aimed at the green synthesis of zinc oxide (ZnO) nanoparticles with seed extracts of Nigella sativa and Pimpinella anisum-loaded nanostructured oil carriers (NLC)-using a mixture of olive and black seed essential oils. The synthesized ZnO NLC were extensively characterized. In addition, the constituent compounds in ZnO NLC were investigated as a potential inhibitor for the SARS-CoV-2 main protease (3CLpro or Mpro) where 27 bioactive constituents, along with ZnO in the nanostructure, were subjected to molecular docking studies. The resultant high-score compounds were further validated by molecular dynamics simulation. The study optimized the compounds dithymoquinone, δ-hederin, oleuropein, and zinc oxide with high docking energy scores (ranging from -7.9 to -9.9 kcal/mol). The RMSD and RMSF data that ensued also mirrored these results for the stability of proteins and ligands. RMSD and RMSF data showed no conformational change in the protein during the MD simulation. Histograms of every simulation trajectory explained the ligand properties and ligand-protein contacts. Nevertheless, further experimental investigations and validation of the selected candidates are imperative to take forward the applicability of the nanostructure as a potent inhibitor of COVID-19 (Coronavirus Disease 2019) for clinical trials.


Assuntos
Tratamento Farmacológico da COVID-19 , Nanoestruturas , Nigella sativa , Pimpinella , Óxido de Zinco , Cisteína Endopeptidases/química , Humanos , Ligantes , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Nigella sativa/metabolismo , Peptídeo Hidrolases/metabolismo , Extratos Vegetais/farmacologia , Inibidores de Proteases/química , SARS-CoV-2 , Sementes/metabolismo , Proteínas não Estruturais Virais/metabolismo , Óxido de Zinco/farmacologia
2.
Acta Biol Hung ; 66(2): 149-60, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-26081271

RESUMO

The present study investigates the protective efficacy of stem bromelain against lead-induced toxicity in male Wistar rats. There were six experimental groups; Group I was negative control, Group II was administered only 20 mg/kg of stem bromelain. Group III and V were orally exposed to 30 mg/kg/day and 60 mg/kg/day of lead acetate, respectively. Group IV and Group VI were exposed to both low and high dose of lead acetate, respectively, and treated with 20 mg/kg stem bromelain. The experimental period was 21 days. The end points evaluated were, lead accumulation in kidney, liver and spleen, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activity, serum malonaldehyde (MDA) cholesterol and triglycerides levels. Co-administration of stem bromelain with lead markedly reduced the lead accumulation in the kidney and spleen. The treatment of stem bromelain also reduced the serum MDA levels in the group exposed to lower dose of lead and serum triglyceride level in the group exposed to higher dose of lead. The lead-induced modulated levels of serum ALT and AST were also alleviated by bromelain treatment. Our key findings suggest a chelating potential of stem bromelain for combating lead toxicity and oxidative stress. Bromelain represents a novel approach to the treatment of metal toxicity and metabolic disorders with a limited therapeutic window.


Assuntos
Bromelaínas/farmacologia , Intoxicação por Chumbo/prevenção & controle , Compostos Organometálicos/toxicidade , Alanina Transaminase/sangue , Animais , Aspartato Aminotransferases/sangue , Rim/metabolismo , Rim/patologia , Intoxicação por Chumbo/sangue , Intoxicação por Chumbo/patologia , Fígado/metabolismo , Fígado/patologia , Masculino , Malondialdeído/sangue , Compostos Organometálicos/farmacocinética , Ratos , Ratos Wistar , Baço/metabolismo , Baço/patologia
3.
J Environ Biol ; 36(6): 1401-8, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26688980

RESUMO

The present studywas undertaken to assess the bioaccumulation potential of cadmium in liver, kidney, gills and muscles of freshwater fish, Nile tilapia Oreochromis niloticus and the changes in oxidative stress indices in liver and kidney with or without simultaneous treatment with waterborne vitamin C and rosemary leaf extract. Adult tilapia were divided into seven groups. Six groups were exposed to sublethal concentrations of Cd, three groups to 5 ppm, while other three to 10 ppm. Two groups from each of the Cd exposed groups were treated with Vitamin C (5ppm) and rosemary leaf extract (2.5 ppm) for a period of 21 days. Cadmium concentration in liver, kidneys and gills was significantly higher in the cadmium exposed groups being invariably high in the groups exposed to 10 ppm CdCl2.H2O.Treatment with Vitamin C and rosemary leaf extract significantly reduced cadmium concentration in comparison to non-treated Cd exposed groups. Treatment with Vitamin C and rosemary leaf extract significantly reduced oxidative stress in Cd exposed fish as evidenced from lower concentration of lipid peroxides and reduced activity of catalase and higher activity of superoxide dismutase in liver and kidney as compared to control fish. Reduction in Cd induced oxidative stress and bioaccumulation was comparable between the two antioxidant treatments, Vitamin C and rosemary leaf extract. The key findings suggest that both the antioxidants used showed ameliorative potential to reduce tissue accumulation of Cd and associated oxidative stress in fresh water fish, Nile tilapia.


Assuntos
Ácido Ascórbico/farmacologia , Cádmio/toxicidade , Estresse Oxidativo/efeitos dos fármacos , Extratos Vegetais/farmacologia , Folhas de Planta/química , Rosmarinus/química , Animais , Antioxidantes/química , Antioxidantes/farmacologia , Doenças dos Peixes/induzido quimicamente , Doenças dos Peixes/tratamento farmacológico , Extratos Vegetais/química , Tilápia
4.
Pak J Pharm Sci ; 26(2): 359-65, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23455208

RESUMO

Phytotherapy has a promising future in the management of diabetes, considered to be less toxic and free from side effects as compared to the use of synthetic drugs. The aim of the present study was to assess the antidiabetic possible of orally administered aqueous extracts of Murraya koenigii (ML) and Olea europaea (OL) leaves (100 and 200 mg/kg doses), in streptozotocin (70 mg/kg) induced diabetic rats. Metformin was used as a standard drug. Blood glucose, cholesterol, triglycerides, creatinine levels and body weight were estimated. ML and OL administration showed significant decrease (p>0.05) in cholesterol, triglyceride, and serum glucose levels (range 55.6%-64.6%) compared to the metformin (62.7%); however, there was no significant effect on body weight and serum creatinine. Our results suggest that both the ML and OL possess a potent antihyperglycemic and hypolipidemic effect, which may be due to the presence of antioxidants such as carbazole alkaloids and polyphenols.


Assuntos
Glicemia/efeitos dos fármacos , Diabetes Mellitus Experimental/tratamento farmacológico , Hipoglicemiantes/farmacologia , Murraya/química , Olea/química , Extratos Vegetais/farmacologia , Administração Oral , Animais , Biomarcadores/metabolismo , Glicemia/metabolismo , Peso Corporal/efeitos dos fármacos , Colesterol/sangue , Creatinina/sangue , Diabetes Mellitus Experimental/sangue , Diabetes Mellitus Experimental/induzido quimicamente , Hipoglicemiantes/administração & dosagem , Hipoglicemiantes/isolamento & purificação , Hipolipemiantes/farmacologia , Masculino , Metformina/farmacologia , Fitoterapia , Extratos Vegetais/administração & dosagem , Extratos Vegetais/isolamento & purificação , Folhas de Planta , Plantas Medicinais , Ratos , Ratos Wistar , Estreptozocina , Triglicerídeos/sangue
5.
Environ Pollut ; 332: 121946, 2023 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-37307860

RESUMO

The aim of the present study was a qualitative assessment of potential microplastics (MPs) in the sewage effluent collected from a local sewage treatment plant located in Riyadh City, Saudi Arabia. The composite samples of domestic sewage effluent were subjected to UV (ultraviolet) light-induced zinc oxide nanoparticles (ZnONPs) mediated photocatalysis. The first phase of the study included the synthesis of the ZnONPs with an extensive characterization. The synthesized nanoparticles were 220 nm in size with a characteristic spherical/hexagonal shape. These NPs were then used at three different concentrations (10 mM, 20 mM, and 30 mM) for the UV light-induced photocatalysis. A shift in the Raman spectra on photodegradation mirrored the surface changes of the functional groups shown by the FTIR spectra; presence of functional groups containing oxygen and C-C bonds associated with oxidation and chain scission. SEM micrographs showed photodegraded particles. Complementary elemental maps from the EDS analysis showed the presence of C, O, and Cl suggesting the potential presence of MPs. The O/C ratio was used to assess potential oxidation degree. In addition, an evaluation of the toxicological effects of the potential MPs in the sewage effluent on Nile tilapia (Oreochromis niloticus) exposed to the effluent at two concentrations (50% and 75%) elicited a marked response in the endpoints evaluated; EROD activity, MDA (malondialdehyde), 8-oxo-2'-deoxyguanosine levels in and AChE (acetylcholinesterase) activity in the brain. Thus, the key results provide new insights into the use of clean technologies to combat global MP pollution in aquatic ecosystems.


Assuntos
Ciclídeos , Nanopartículas , Óxido de Zinco , Animais , Ciclídeos/metabolismo , Microplásticos/metabolismo , Óxido de Zinco/química , Plásticos/metabolismo , Esgotos , Acetilcolinesterase/metabolismo , Ecossistema
6.
Food Chem Toxicol ; 146: 111840, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33137427

RESUMO

Contamination of cereal crops with zearalenone (ZEA), a mycotoxin produced by Fusarium fungi, is a worldwide health concern. The study assessed the ameliorative potential of resveratrol (RSV), a potent antioxidant against ZEA induced toxicity in adult male Wistar rats. Rats (n = 40), with an average weight of 100-150 g were used for the exposure study for three weeks. The animals were divided into four groups (I to IV) each comprising 10 rats. Group I was kept as negative control and was administered normal saline. Group II and III were exposed to 2 mg/kg of the mycotoxin, ZEA administered intraperitoneally once every week. Group III was treated with resveratrol (RSV) orally (5 mg/kg) daily. Group IV was treated only with resveratrol (5 mg/kg/daily) as a positive control. The protective effect of resveratrol was evaluated on; biochemical variables, biomarkers of oxidative stress, markers of immunotoxicity, and DNA damage. The findings showed that exposure to ZEA elicited oxidative stress and modulated the antioxidant enzyme activities. A disarray in the lipid profile, parameters of the humoral and cellular immune response; serum cytokines and immunoglobulins was also observed. Further, COMET assay showed detectable DNA lesions. Taken together, RSV was efficacious in reducing and/or reversing the ZEA induced toxicity.


Assuntos
Estresse Oxidativo/efeitos dos fármacos , Resveratrol/farmacologia , Zearalenona/toxicidade , Animais , Antioxidantes/farmacologia , Ensaio Cometa , Dano ao DNA/efeitos dos fármacos , Imunotoxinas , Masculino , Ratos , Ratos Wistar
7.
Crit Rev Food Sci Nutr ; 49(10): 868-913, 2009 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-19960394

RESUMO

The obesity epidemic is a global issue and shows no signs of abating, while the cause of this epidemic remains unclear. Marketing practices of energy-dense foods and institutionally-driven declines in physical activity are the alleged perpetrators for the epidemic, despite a lack of solid evidence to demonstrate their causal role. While both may contribute to obesity, we call attention to their unquestioned dominance in program funding and public efforts to reduce obesity, and propose several alternative putative contributors that would benefit from equal consideration and attention. Evidence for microorganisms, epigenetics, increasing maternal age, greater fecundity among people with higher adiposity, assortative mating, sleep debt, endocrine disruptors, pharmaceutical iatrogenesis, reduction in variability of ambient temperatures, and intrauterine and intergenerational effects as contributing factors to the obesity epidemic are reviewed herein. While the evidence is strong for some contributors such as pharmaceutical-induced weight gain, it is still emerging for other reviewed factors. Considering the role of such putative etiological factors of obesity may lead to comprehensive, cause specific, and effective strategies for prevention and treatment of this global epidemic.


Assuntos
Obesidade/epidemiologia , Animais , Causalidade , Humanos
8.
Asian Pac J Cancer Prev ; 14(11): 6739-42, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24377598

RESUMO

BACKGROUND: Breast cancer is a major health problem worldwide. Olive oil induces apoptosis in some cancer cells due to phenolic compounds like oleuropein. Although oleuropein has anticancer activity, the underlying mechanisms of action remain unknown. The study aimed to assess the mechanism of oleuropin-induced breast cancer cell apoptosis. MATERIALS AND METHODS: p53, Bcl-2 and Bax gene expression was evaluated by semi-quantitative reverse transcriptase polymerase chain reaction (RT-PCR) in luminal MCF-7 cells. RESULTS: Oleuropein-induced apoptosis was accompanied by up-regulation of both p53 and Bax gene expression levels and down-regulation in Bcl2. CONCLUSIONS: Oleuropein induces apoptosis in breast tumour cells via a p53-dependent pathway mediated by Bax and Bcl2 genes. Therefore, oleuropein may have therapeutic potential in breast cancer patients by inducing apoptosis via activation of the p53 pathway.


Assuntos
Anti-Hipertensivos/farmacologia , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/patologia , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Iridoides/farmacologia , Proteínas Proto-Oncogênicas c-bcl-2/genética , Proteína Supressora de Tumor p53/genética , Proteína X Associada a bcl-2/genética , Western Blotting , Neoplasias da Mama/genética , Proliferação de Células/efeitos dos fármacos , Feminino , Humanos , Glucosídeos Iridoides , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , RNA Mensageiro/genética , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Células Tumorais Cultivadas , Proteína Supressora de Tumor p53/metabolismo , Proteína X Associada a bcl-2/metabolismo
9.
Food Chem Toxicol ; 53: 310-6, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23261678

RESUMO

Breast cancer constitutes a major health problem for women worldwide. However, its incidence varies between populations and geographical locations. These variations could be diet-related, since there are several carcinogenic compounds in the modern diet, while natural products contain various anti-cancer elements. Several lines of evidence indicate that, in addition to their clear preventive effect, these compounds could also be used as therapeutic agents. In the present report we have shown that oleuropein, a pharmacologically safe natural product of olive leaf, has potent anti-breast cancer properties. Indeed, oleuropein exhibits specific cytotoxicity against breast cancer cells, with higher effect on the basal-like MDA-MB-231 cells than on the luminal MCF-7 cells. This effect is mediated through the induction of apoptosis via the mitochondrial pathway. Moreover, oleuropein inhibits cell proliferation by delaying the cell cycle at S phase and up-regulated the cyclin-dependent inhibitor p21. Furthermore, oleuropein inhibited the anti-apoptosis and pro-proliferation protein NF-κB and its main oncogenic target cyclin D1. This inhibition could explain the great effect of oleuropein on cell proliferation and cell death of breast cancer cells. Therefore, oleuropein warrants further investigations to prove its utility in preventing/treating breast cancer, especially the less-responsive basal-like type.


Assuntos
Antineoplásicos/farmacologia , Neoplasias da Mama/tratamento farmacológico , Óleos de Plantas/farmacologia , Piranos/farmacologia , Apoptose/efeitos dos fármacos , Ciclo Celular , Proliferação de Células/efeitos dos fármacos , Ciclina D1/metabolismo , Inibidor de Quinase Dependente de Ciclina p21/genética , Inibidor de Quinase Dependente de Ciclina p21/metabolismo , Eletroforese em Gel de Poliacrilamida , Feminino , Citometria de Fluxo , Humanos , Glucosídeos Iridoides , Iridoides , Células MCF-7 , Mitocôndrias/metabolismo , NF-kappa B/genética , NF-kappa B/metabolismo , Azeite de Oliva , Receptores de Estrogênio/metabolismo , Regulação para Cima
10.
Oxid Med Cell Longev ; 2012: 194829, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22888396

RESUMO

Reactive oxygen species (ROS) are cytotoxic agents that lead to significant oxidative damage. Bisphenol A (BPA) is a contaminant with increasing exposure to it and exerts both toxic and estrogenic effects on mammalian cells. Due to limited information concerning the effect of BPA on liver, this study investigates whether BPA causes hepatotoxicity by induction of oxidative stress in liver. Rats were divided into five groups: The first four groups, BPA (0.1, 1, 10, 50 mg/kg/day) were administrated orally to rats for four weeks. The fifth group was taken water with vehicle. The final body weights in the 0.1 mg group showed a significant decrease compared to control group. Significant decreased levels of reduced glutathione, superoxide dismutase, glutathione peroxidase, glutathione-S-transferase, glutathione reductase and catalase activity were found in the 50 mg BPA group compared to control groups. High dose of BPA (50 mg/kg) significantly increased the biochemical levels of ALT, ALP and total bilirubin. BPA effect on the activity of antioxidant genes was confirmed by real time PCR in which the expression levels of these genes in liver tissue were significantly decrease compared to control. Data from this study demonstrate that BPA generate ROS and reduce the antioxidant gene expression that causes hepatotoxicity.


Assuntos
Hepatopatias/patologia , Estresse Oxidativo/efeitos dos fármacos , Fenóis/toxicidade , Animais , Compostos Benzidrílicos , Bilirrubina/metabolismo , Biomarcadores/metabolismo , Peso Corporal/efeitos dos fármacos , Modelos Animais de Doenças , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Fígado/efeitos dos fármacos , Fígado/enzimologia , Fígado/patologia , Hepatopatias/enzimologia , Hepatopatias/genética , Masculino , Nitrosação/efeitos dos fármacos , Tamanho do Órgão/efeitos dos fármacos , Ratos , Ratos Wistar
11.
Asian Pac J Cancer Prev ; 13(9): 4555-9, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-23167379

RESUMO

Breast cancer causes death due to distant metastases in which tumor cells produce matrix metalloproteinase (MMP) enzymes which facilitate invasion. Oleuropein, the main olive oil polyphenol, has anti-proliferative effects. This study aimed to investigate the effect of oleuropein on the metastatic and anti-metastatic gene expression in the MDA human breast cancer cell line. We evaluated the MMPs and TIMPs gene expression by semi-quantitative reverse transcriptase polymerase chain reaction (RT-PCR) in treated and untreated cells. This study demonstrated that OL may induce anti-metastatic effects on human breast cancer cells. We found that TIMP1,-3, and -4 were over-expressed after all periods of incubation in treated cancer cells compared to untreated cells, while MMP2 and MMP9 genes were down-regulated, at least initially. Treatment of breast cancer cells with oleuropein could help in prevention of cancer metastasis by increasing the TIMPs and suppressing the MMPs gene expressions.


Assuntos
Antineoplásicos/farmacologia , Neoplasias da Mama/genética , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Piranos/farmacologia , Análise de Variância , Neoplasias da Mama/patologia , Linhagem Celular Tumoral , Regulação para Baixo/efeitos dos fármacos , Humanos , Glucosídeos Iridoides , Iridoides , Metaloproteinase 2 da Matriz/genética , Metaloproteinase 9 da Matriz/genética , Metástase Neoplásica , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Inibidor Tecidual de Metaloproteinase-1/genética , Inibidor Tecidual de Metaloproteinase-3/genética , Inibidores Teciduais de Metaloproteinases/genética , Regulação para Cima/efeitos dos fármacos , Inibidor Tecidual 4 de Metaloproteinase
12.
Int J Environ Res Public Health ; 7(9): 3332-47, 2010 09.
Artigo em Inglês | MEDLINE | ID: mdl-20948927

RESUMO

It is conceivable that toxic metals contribute to obesity by influencing various aspects of metabolism, such as by substituting for essential micronutrients and vital metals, or by inducing oxidative stress. Deficiency of the essential metal zinc decreases adiposity in humans and rodent models, whereas deficiencies of chromium, copper, iron, and magnesium increases adiposity. This study utilized the NHANES 99-02 data to explore the association between waist circumference and body mass index with the body burdens of selected toxic metals (barium, cadmium, cobalt, cesium, molybdenum, lead, antimony, thallium, and tungsten). Some of the associations were significant direct relationships (barium and thallium), and some of the associations were significant inverse relationships (cadmium, cobalt, cesium, and lead). Molybdenum, antimony, and tungsten had mostly insignificant associations with waist circumference and body mass index. This is novel result for most of the toxic metals studied, and a surprising result for lead because high stored lead levels have been shown to correlate with higher rates of diabetes, and obesity may be a key risk factor for developing diabetes. These associations suggest the possibility that environmental exposure to metals may contribute to variations in human weight gain/loss. Future research, such as prospective studies rather than the cross-sectional studies presented here, is warranted to confirm these findings.


Assuntos
Metais/urina , Obesidade/epidemiologia , Adolescente , Adulto , Carga Corporal (Radioterapia) , Índice de Massa Corporal , Criança , Pré-Escolar , Estudos Transversais , Exposição Ambiental , Feminino , Humanos , Masculino , Metais/toxicidade , Pessoa de Meia-Idade , Inquéritos Nutricionais , Obesidade/prevenção & controle , Estados Unidos/epidemiologia , Circunferência da Cintura , Adulto Jovem
13.
Int J Environ Res Public Health ; 7(7): 2988-3005, 2010 07.
Artigo em Inglês | MEDLINE | ID: mdl-20717554

RESUMO

Recent evidence suggests that endocrine disrupting chemicals (EDCs) may cause perturbations in endogenous hormonal regulation that predispose to weight gain. Using data from NHANES (1999-2002), we investigated the association between body mass index (BMI), waist circumference (WC) and selected persistent organic pollutants (POPs) via multiple linear regressions. Consistent interaction was found between gender, ln oxychlordane and ln p,p' DDT. Also, we found an association between WC and ln oxychlordane and ln hpcdd in subjects with detectable levels of POPs, whereas an association between WC and ln p,p' DDT was observed in all subjects. Furthermore, ln Ocdd showed an increase with higher WC and BMI, whereas, ln trans-nonachlor decreased with higher BMI. Hence, BMI and WC are associated with POPs levels, making the chemicals plausible contributors to the obesity epidemic.


Assuntos
Índice de Massa Corporal , Dioxinas/efeitos adversos , Disruptores Endócrinos/efeitos adversos , Hidrocarbonetos Clorados/efeitos adversos , Obesidade/etiologia , Adolescente , Adulto , Criança , Estudos Transversais , Feminino , Humanos , Masculino , Inquéritos Nutricionais , Saúde Pública , Análise de Regressão , Estados Unidos , Relação Cintura-Quadril , Adulto Jovem
14.
Med Decis Making ; 30(1): 68-75, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-19675318

RESUMO

OBJECTIVE: To evaluate patient opinions on acceptable risks in exchange for a given degree of weight loss and their implications for sample size determination in obesity randomized clinical trials (RCTs). DESIGN: . Survey of patients entering RCTs for weight loss in a university-based clinical research setting and power calculations based on their responses. Participants. Men (n = 8) and women (n = 66) between 24 and 73 years of age with body mass indices ranging from 26.8 to 40.5 kg/m(2). Measurements. Survey responses to questions assessing the added risk of serious adverse events (SAEs) or death one is willing to assume for a given degree of weight loss. RESULTS: For 5% and 10% weight loss against risk for death per se, the mean acceptable risk tended to be about 3.5%, but the median (0.00) and mode (0.00) suggested that for most individuals, only a risk of < or = 1% would be acceptable. Figures, estimated dropout rates, and base rates of SAEs (including deaths) from recent obesity trials indicate that 1-year 2-group obesity RCTs would need tens of thousands of participants per group to have 80% power to detect risks that are meaningful to patients at the 2-tailed 0.05 alpha level. CONCLUSION: Patient education is needed to explain which risks are realistically detectable in RCTs so that patients may provide truly informed consent, or RCT standards should be modified to meet patients' implicit expectations.


Assuntos
Obesidade , Pacientes/psicologia , Ensaios Clínicos Controlados Aleatórios como Assunto , Tamanho da Amostra , Adulto , Idoso , Coleta de Dados , Feminino , Humanos , Consentimento Livre e Esclarecido , Masculino , Pessoa de Meia-Idade , Medição de Risco , Redução de Peso/fisiologia , Adulto Jovem
15.
PLoS One ; 4(8): e6624, 2009 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-19675667

RESUMO

BACKGROUND: Dropouts and missing data are nearly-ubiquitous in obesity randomized controlled trails, threatening validity and generalizability of conclusions. Herein, we meta-analytically evaluate the extent of missing data, the frequency with which various analytic methods are employed to accommodate dropouts, and the performance of multiple statistical methods. METHODOLOGY/PRINCIPAL FINDINGS: We searched PubMed and Cochrane databases (2000-2006) for articles published in English and manually searched bibliographic references. Articles of pharmaceutical randomized controlled trials with weight loss or weight gain prevention as major endpoints were included. Two authors independently reviewed each publication for inclusion. 121 articles met the inclusion criteria. Two authors independently extracted treatment, sample size, drop-out rates, study duration, and statistical method used to handle missing data from all articles and resolved disagreements by consensus. In the meta-analysis, drop-out rates were substantial with the survival (non-dropout) rates being approximated by an exponential decay curve (e(-lambdat)) where lambda was estimated to be .0088 (95% bootstrap confidence interval: .0076 to .0100) and t represents time in weeks. The estimated drop-out rate at 1 year was 37%. Most studies used last observation carried forward as the primary analytic method to handle missing data. We also obtained 12 raw obesity randomized controlled trial datasets for empirical analyses. Analyses of raw randomized controlled trial data suggested that both mixed models and multiple imputation performed well, but that multiple imputation may be more robust when missing data are extensive. CONCLUSION/SIGNIFICANCE: Our analysis offers an equation for predictions of dropout rates useful for future study planning. Our raw data analyses suggests that multiple imputation is better than other methods for handling missing data in obesity randomized controlled trials, followed closely by mixed models. We suggest these methods supplant last observation carried forward as the primary method of analysis.


Assuntos
Obesidade/terapia , Ensaios Clínicos Controlados Aleatórios como Assunto , Redução de Peso , Interpretação Estatística de Dados , Humanos
16.
Curr Opin Endocrinol Diabetes Obes ; 15(5): 403-8, 2008 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-18769210

RESUMO

PURPOSE OF REVIEW: There has been a substantial increase in the prevalence of obesity in the last several decades. Recent evidence suggests that endocrine-disrupting chemicals, for example halogenated aromatic hydrocarbons, may cause perturbations in endogenous hormonal regulation and alter other mechanisms involved in weight homeostasis, which may lead to weight gain by increased volume of adipose tissue. Synthetic chemicals derived from industrial processes are suspected to play a contributory role. Yet of the approximately 70,000 documented synthetic chemicals, few have been examined to determine their effects on the endocrine system. RECENT FINDINGS: The present study examines prior laboratory, epidemiological and experimental research findings. Data demonstrate migration of endocrine disruptors in the environment and are beginning to catalogue their effects on adiposity. We present postulated relationships between these chemicals, their mechanisms of action, and the obesity epidemic. SUMMARY: Endocrine disruptors may adversely impact human and environmental health by altering the physiological control mechanism. Obesity, which is known to increase medical costs and reduce quality and length of life, may be increasing as a function of endocrine disruptor exposure. This merits concern among scientists and public health officials and warrants additional vigorous research in this area.


Assuntos
Disruptores Endócrinos/efeitos adversos , Poluentes Ambientais/efeitos adversos , Obesidade/epidemiologia , Obesidade/etiologia , Animais , Disruptores Endócrinos/química , Exposição Ambiental/efeitos adversos , Hormônios , Humanos
17.
Obesity (Silver Spring) ; 15(10): 2380-3, 2007 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-17925462

RESUMO

OBJECTIVE: The objective of this investigation was to examine the relationship between BMI and waist circumference (WC) by gender and race subgroups from U.S. population-based data from 1959 to 2004 and to investigate the trend in WC over calendar time. RESEARCH METHODS AND PROCEDURES: Demographic and anthropometric cross-sectional data on 30,730 participants 18 to 79 years old across five national surveys were included. We regressed WC on BMI while controlling for age in each time period for blacks and whites by gender. RESULTS: The relationship between BMI and WC as characterized by the slope of the linear regression of WC on BMI does not seem to be changing significantly over time. A small (range, 0.08 to 0.27 cm/yr) increase in WC over time was observed. DISCUSSION: The implications of these findings for public health and for understanding any extant changes in the BMI-mortality rate relationship remain to be elucidated.


Assuntos
Índice de Massa Corporal , Relação Cintura-Quadril , Adolescente , Adulto , Fatores Etários , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fatores Sexuais
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