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1.
Food Chem Toxicol ; 169: 113445, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36183923

RESUMO

Dietary supplements (DS) constitute a widely used group of products comprising vitamin, mineral, and botanical extract formulations. DS of botanical or herbal origins (HDS) comprise nearly 30% of all DS and are presented on the market either as single plant extracts or multi-extract-containing products. Despite generally safe toxicological profiles of most products currently present on the market, rising cases of liver injury caused by HDS - mostly by multi-ingredient and adulterated products - are of particular concern. Here we discuss the most prominent historical cases of HDS-induced hepatotoxicty - from Ephedra to Hydroxycut and OxyELITE Pro-NF, as well as products with suspected hepatotoxicity that are either currently on or are entering the market. We further provide discussion on overcoming the existing challenges with HDS-linked hepatotoxicity by introduction of advanced in silico, in vitro, in vivo, and microphysiological system approaches to address the matter of safety of those products before they reach the market.


Assuntos
Doença Hepática Induzida por Substâncias e Drogas , Suplementos Nutricionais , Extratos Vegetais , Humanos , Doença Hepática Induzida por Substâncias e Drogas/etiologia , Suplementos Nutricionais/toxicidade , Extratos Vegetais/toxicidade , Vitaminas/toxicidade , Preparações de Plantas
2.
Birth Defects Res ; 114(3-4): 136-144, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-34967143

RESUMO

PURPOSE: To investigate the factors that influence the occurrence of anorectal malformations (ARMs). METHODS: From December 2018 to December 2019, 136 children treated for ARMs at the Children's Hospital of Chongqing Medical University were included in the case group. The control group consisted of children with intussusception or perianal abscesses. A uniform questionnaire was filled by the parents of the enrolled children. RESULTS: The birth weight of the cases was significantly lower than that of the controls (p < .01), and children with ARMs were more likely to be complicated with single umbilical artery (SUA) (p < .001). Maternal upper respiratory tract infection (adjusted odds ratio [ORadj ], 2.44; 95% confidence interval [CI], 1.29-4.63) and urogenital infection (ORadj , 2.67; 95% CI 1.11-6.38) during the first trimester of pregnancy, anemia during pregnancy (ORadj , 5.69; 95% CI, 1.01-32.07), and exposure to hazardous substances 6 months before pregnancy and during the first trimester of pregnancy (ORadj , 13.82; 95% CI, 3.86-49.35) are associated with increased risk of ARMs. Folic acid supplements (ORadj , 0.31; 95% CI, 0.14-0.65) and multivitamin (ORadj , 0.34; 95% CI, 0.15-0.79) had a protective effect on ARMs. Paternal drug use (ORadj , 9.17; 95% CI, 2.19-38.49) 6 months before their wives' conception increased the risk of ARMs. CONCLUSION: Maternal infection, anemia during pregnancy, and maternal hazardous substances exposure are possible risk factors for ARMs. Folic acid supplements and multivitamin can reduce the occurrence of ARMs. Meanwhile, paternal drug use may also be a risk factor for ARMs.


Assuntos
Malformações Anorretais , Malformações Anorretais/complicações , Malformações Anorretais/epidemiologia , Criança , Feminino , Ácido Fólico/uso terapêutico , Substâncias Perigosas , Humanos , Gravidez , Fatores de Risco , Vitaminas/toxicidade
3.
J Fam Pract ; 70(8): 386-398, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34818175

RESUMO

This review, with handy tables, summarizes which vitamins offer proven benefits-and which don't.


Assuntos
Suplementos Nutricionais/normas , Vitaminas/metabolismo , Vitaminas/farmacologia , Humanos , Vitaminas/toxicidade
4.
Int J Pharm ; 571: 118717, 2019 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-31610279

RESUMO

The fat-soluble vitamins lipid injectable emulsion, a parenteral supplement, commonly used for hospitalized patients to meet daily requirements of fat-soluble vitamins. This study attempts to reduce risk, improve the stability and safety of fat-soluble vitamins lipid injectable emulsion using a Quality by Design (QbD) approach. The quality target product profile and critical quality attributes were defined based on a comprehensive understanding of fat-soluble vitamins lipid injectable emulsions. The emulsions were prepared using a high-pressure homogenization method. Critical quality attributes (CQAs) were identified using risk assessment tools such as fishbone diagram and risk estimation matrix. The assay, mean droplet size, polydispersity index, zeta potential, and the volume-weighted percentage of fat greater than 5 µm (PFAT5) were identified as CQAs. Accordingly, three critical formulation and process parameters for the emulsions were the percentage of emulsifier, homogenization pressure, and homogenization recirculation. The design space was obtained via a design of experiment (DoE), and an optimum formulation was successfully prepared. All physicochemical attributes of the optimal formulation were within the design space (i.e., droplet size: 217.2 ±â€¯0.37 nm; polydispersity index: 0.115 ±â€¯0.012; PFAT5: less than 0.05%; zeta potential: -34.6 ±â€¯1.09 mV; and viscosity: 20.95 mPa at 0.1 s-1). The optimal formulation remained acceptable physicochemical stability at 25 ±â€¯2 °C/60% RH ±â€¯5% RH over a 12-month period. Safety of the optimal emulsion was evaluated as acceptable through the determination of lysophospholipid content and an in vitro hemolysis assay. In conclusion, an optimal lipid injectable emulsion for fat-soluble vitamins was successfully prepared using a QbD approach.


Assuntos
Composição de Medicamentos/normas , Emulsões Gordurosas Intravenosas/administração & dosagem , Lipídeos/química , Solventes/química , Vitaminas/administração & dosagem , Animais , Química Farmacêutica/métodos , Composição de Medicamentos/métodos , Estabilidade de Medicamentos , Eritrócitos , Emulsões Gordurosas Intravenosas/química , Emulsões Gordurosas Intravenosas/toxicidade , Hemólise/efeitos dos fármacos , Lipídeos/toxicidade , Tamanho da Partícula , Controle de Qualidade , Coelhos , Projetos de Pesquisa , Solventes/toxicidade , Testes de Toxicidade , Viscosidade , Vitaminas/química , Vitaminas/toxicidade
5.
Mult Scler ; 25(9): 1326-1328, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-30358476

RESUMO

Knowledge about complications of chronic ultra-high dose vitamin D supplementation is limited. We report a patient with primary progressive multiple sclerosis (MS) who presented with generalized weakness caused by hypercalcemia after uncontrolled intake of more than 50,000 IU of cholecalciferol per day over several months. Various treatment strategies were required to achieve normocalcemia. However, renal function improved only partly and further progression of MS was observed. We conclude that patients need to be informed about the risks of uncontrolled vitamin D intake and neurologists need to be alert of biochemical alterations and symptoms of vitamin D toxicity.


Assuntos
Colecalciferol/toxicidade , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos , Hipercalcemia/induzido quimicamente , Esclerose Múltipla Crônica Progressiva/tratamento farmacológico , Vitaminas/toxicidade , Colecalciferol/administração & dosagem , Humanos , Hipercalcemia/complicações , Masculino , Pessoa de Meia-Idade , Insuficiência Renal/etiologia , Vitaminas/administração & dosagem
6.
Nutrients ; 10(5)2018 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-29710765

RESUMO

Physical exercise is beneficial for general health and is an effective treatment for metabolic disorders. Vitamin E is widely used as dietary supplement and is considered to improve non-alcoholic fatty liver disease by reducing inflammation and dyslipidemia. However, increased vitamin E intake may interfere with adaptation to exercise training. Here, we explored how vitamin E alters the acute exercise response of the liver, an organ that plays an essential metabolic role during physical activity. Mice fed a control or an α-tocopherol-enriched diet were subjected to a non-exhaustive treadmill run. We assessed the acute transcriptional response of the liver as well as glucocorticoid signalling and plasma free fatty acids (FFA) and performed indirect calorimetry. Vitamin E interfered with the exercise-induced increase in FFA and upregulation of hepatic metabolic regulators, and it shifted the transcriptional profile of exercised mice towards lipid and cholesterol synthesis while reducing inflammation. Energy utilization, as well as corticosterone levels and signalling were similar, arguing against acute differences in substrate oxidation or glucocorticoid action. Our results show that high-dose vitamin E alters the metabolic and inflammatory response of the liver to physical exercise. The interference with these processes may suggest a cautious use of vitamin E as dietary supplement.


Assuntos
Antioxidantes/administração & dosagem , Fígado/efeitos dos fármacos , Esforço Físico , Vitaminas/administração & dosagem , alfa-Tocoferol/administração & dosagem , Adaptação Fisiológica , Animais , Antioxidantes/toxicidade , Colesterol/sangue , Corticosterona/sangue , Metabolismo Energético/efeitos dos fármacos , Metabolismo Energético/genética , Ácidos Graxos não Esterificados/sangue , Mediadores da Inflamação/metabolismo , Metabolismo dos Lipídeos/efeitos dos fármacos , Metabolismo dos Lipídeos/genética , Fígado/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Modelos Animais , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Receptores de Glucocorticoides/efeitos dos fármacos , Receptores de Glucocorticoides/metabolismo , Corrida , Fatores de Tempo , Transcrição Gênica/efeitos dos fármacos , Vitaminas/toxicidade , alfa-Tocoferol/toxicidade
7.
Nurse Pract ; 43(5): 22-30, 2018 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-29668516

RESUMO

Vitamin D deficiency is an increasing problem affecting all ages. Patients should be assessed for risk factors as part of preventive health maintenance. Vitamin D toxicity is a rare occurrence caused by oversupplementation and errors in food fortification. The connection between vitamin D deficiency and osteoporosis, is well established. However, a cause and effect relationship has yet to be established between vitamin D deficiency and many chronic illnesses. An evidence-based approach is treating patients for an underlying vitamin D deficiency in hopes of improving many chronic illnesses.


Assuntos
Deficiência de Vitamina D/complicações , Vitamina D/toxicidade , Vitaminas/toxicidade , Acidentes por Quedas , Doença de Alzheimer/etiologia , Asma/etiologia , Doenças Cardiovasculares/etiologia , Demência/etiologia , Diabetes Mellitus/sangue , Dieta , Humanos , Síndrome do Intestino Irritável/complicações , Neoplasias/mortalidade , Osteomalacia/etiologia , Desempenho Físico Funcional , Recomendações Nutricionais , Infecções Respiratórias/etiologia , Raquitismo/etiologia , Fatores de Risco , Vitamina D/fisiologia , Vitamina D/uso terapêutico , Deficiência de Vitamina D/etiologia , Vitaminas/uso terapêutico
8.
Toxicol In Vitro ; 44: 206-212, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28716455

RESUMO

Vitamin B6 is a water-soluble vitamin that functions as a coenzyme in many reactions involved in amino acid, carbohydrates and lipid metabolism. Since 2014, >50 cases of sensory neuronal pain due to vitamin B6 supplementation were reported. Up to now, the mechanism of this toxicity is enigmatic and the contribution of the various B6 vitamers to this toxicity is largely unknown. In the present study, the neurotoxicity of the different forms of vitamin B6 is tested on SHSY5Y and CaCo-2 cells. Cells were exposed to pyridoxine, pyridoxamine, pyridoxal, pyridoxal-5-phosphate or pyridoxamine-5-phosphate for 24h, after which cell viability was measured using the MTT assay. The expression of Bax and caspase-8 was tested after the 24h exposure. The effect of the vitamers on two pyridoxal-5-phosphate dependent enzymes was also tested. Pyridoxine induced cell death in a concentration-dependent way in SHSY5Y cells. The other vitamers did not affect cell viability. Pyridoxine significantly increased the expression of Bax and caspase-8. Moreover, both pyridoxal-5-phosphate dependent enzymes were inhibited by pyridoxine. In conclusion, the present study indicates that the neuropathy observed after taking a relatively high dose of vitamin B6 supplements is due to pyridoxine. The inactive form pyridoxine competitively inhibits the active pyridoxal-5'-phosphate. Consequently, symptoms of vitamin B6 supplementation are similar to those of vitamin B6 deficiency.


Assuntos
Suplementos Nutricionais/toxicidade , Piridinas/toxicidade , Alanina Transaminase/metabolismo , Células CACO-2 , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Humanos , Polineuropatias/induzido quimicamente , Tirosina Descarboxilase/metabolismo , Deficiência de Vitamina B 6 , Vitaminas/toxicidade
9.
Asia Pac J Clin Nutr ; 25(3): 636-50, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27440700

RESUMO

BACKGROUND AND OBJECTIVES: This work represents the second part of a progressive review of AuSPEN's 1999 Guidelines for Provision of Micronutrient Supplementation in adult patients receiving parenteral nutrition. METHODS AND STUDY DESIGN: A systematic literature review was undertaken and recommendations made based on the available evidence and with consideration to specific elements of the Australian and New Zealand (NZ) practice environment. The strength of evidence underpinning each recommendation was assessed. A multidisciplinary steering committee and external reviewers provided feedback on the guidelines. RESULTS: On review of the available literature it appears that the parenteral multivitamin preparations presently available in Australia and NZ are to sufficient avoid deficiency without causing toxicity in most clinical situations for adults receiving PN when provided regularly as part of the PN prescription. Vitamin D is the most vulnerable vitamin for the Australian and NZ PN population. CONCLUSIONS: Vitamins are an essential component of PN and should be provided from commencement for all patients receiving PN. With the exception of vitamin D, which is recommended to be monitored annually, routine monitoring of vitamin levels is unlikely to be necessary in patients receiving regular parenteral multivitamin preparations. Clinical judgement is an important element when assessing, prescribing and monitoring patients receiving PN. Areas requiring further research have been identified.


Assuntos
Nutrição Parenteral/métodos , Vitaminas/administração & dosagem , Adulto , Austrália , Nutrição Enteral , Humanos , Nova Zelândia , Sociedades Médicas , Vitaminas/toxicidade
10.
Nutr Clin Pract ; 30(4): 559-69, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26113560

RESUMO

The American Society for Parenteral and Enteral Nutrition (A.S.P.E.N.) started an intensive review of commercially available parenteral vitamin and trace element (TE) products in 2009. The chief findings were that adult multi-TE products currently available in the United States (U.S.) provide potentially toxic amounts of manganese, copper, and chromium, and neonatal/pediatric multi-TE products provide potentially toxic amounts of manganese and chromium. The multivitamin products appeared safe and effective; however, a separate parenteral vitamin D product is needed for those patients on standard therapy who continue to be vitamin D depleted and are unresponsive to oral supplements. The review process also extended to parenteral choline and carnitine. Although choline and carnitine are not technically vitamins or trace elements, choline is an essential nutrient in all age groups, and carnitine is an essential nutrient in infants, according to the Food and Nutrition Board of the Institute of Medicine. A parenteral choline product needs to be developed and available. Efforts are currently under way to engage the U.S. Food and Drug Administration (FDA) and the parenteral nutrient industry so A.S.P.E.N.'s recommendations can become a commercial reality.


Assuntos
Suplementos Nutricionais/normas , Micronutrientes/normas , Nutrição Parenteral/normas , United States Food and Drug Administration/normas , Adulto , Carnitina/normas , Carnitina/toxicidade , Colina/normas , Colina/toxicidade , Suplementos Nutricionais/toxicidade , Aprovação de Drogas , Humanos , Lactente , Lipotrópicos/normas , Lipotrópicos/toxicidade , Micronutrientes/toxicidade , Oligoelementos/normas , Oligoelementos/toxicidade , Estados Unidos , Vitamina D/normas , Vitamina D/toxicidade , Vitaminas/normas , Vitaminas/toxicidade
12.
Toxicology ; 321: 62-72, 2014 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-24721472

RESUMO

Drug-induced liver injury (DILI) is one of the most common drug-induced adverse events (AEs) leading to life-threatening conditions such as acute liver failure. It has also been recognized as the single most common cause of safety-related post-market withdrawals or warnings. Efforts to develop new predictive methods to assess the likelihood of a drug being a hepatotoxicant have been challenging due to the complexity and idiosyncrasy of clinical manifestations of DILI. The FDA adverse event reporting system (AERS) contains post-market data that depict the morbidity of AEs. Here, we developed a scalable approach to construct a hepatotoxicity database using post-market data for the purpose of quantitative structure-activity relationship (QSAR) modeling. A set of 2029 unique and modelable drug entities with 13,555 drug-AE combinations was extracted from the AERS database using 37 hepatotoxicity-related query preferred terms (PTs). In order to determine the optimal classification scheme to partition positive from negative drugs, a manually-curated DILI calibration set composed of 105 negatives and 177 positives was developed based on the published literature. The final classification scheme combines hepatotoxicity-related PT data with supporting information that optimize the predictive performance across the calibration set. Data for other toxicological endpoints related to liver injury such as liver enzyme abnormalities, cholestasis, and bile duct disorders, were also extracted and classified. Collectively, these datasets can be used to generate a battery of QSAR models that assess a drug's potential to cause DILI.


Assuntos
Doença Hepática Induzida por Substâncias e Drogas/patologia , Testes de Toxicidade/estatística & dados numéricos , Algoritmos , Ampicilina/toxicidade , Animais , Antibacterianos/toxicidade , Anti-Inflamatórios não Esteroides/toxicidade , Ácido Ascórbico/toxicidade , Doenças dos Ductos Biliares/induzido quimicamente , Doenças dos Ductos Biliares/patologia , Calibragem , Doença Hepática Induzida por Substâncias e Drogas/classificação , Doença Hepática Induzida por Substâncias e Drogas/enzimologia , Colestase/induzido quimicamente , Colestase/patologia , Mineração de Dados , Bases de Dados Factuais , Rotulagem de Medicamentos , Determinação de Ponto Final , Humanos , Levofloxacino/toxicidade , Fígado/enzimologia , Fígado/patologia , Naproxeno/toxicidade , Vigilância de Produtos Comercializados , Relação Quantitativa Estrutura-Atividade , Vitaminas/toxicidade
13.
Arch Toxicol ; 87(12): 2083-103, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24173581

RESUMO

The high worldwide prevalence of vitamin D deficiency is largely the result of low sunlight exposure with subsequently limited cutaneous vitamin D production. Classic manifestations of vitamin D deficiency are linked to disturbances in bone and mineral metabolism, but the identification of the vitamin D receptor in almost every human cell suggests a broader role of vitamin D for overall and cardiovascular health. The various cardiovascular protective actions of vitamin D such as anti-diabetic and anti-hypertensive effects including renin suppression as well as protection against atherosclerosis and heart diseases are well defined in previous experimental studies. In line with this, large epidemiological studies have highlighted vitamin D deficiency as a marker of cardiovascular risk. However, randomized controlled trials (RCTs) on vitamin D have largely failed to show its beneficial effects on cardiovascular diseases and its conventional risk factors. While most prior vitamin D RCTs were not designed to assess cardiovascular outcomes, some large RCTs have been initiated to evaluate the efficacy of vitamin D supplementation on cardiovascular events in the general population. When considering the history of previous disappointing vitamin RCTs in general populations, more emphasis should be placed on RCTs among severely vitamin D-deficient populations who would most likely benefit from vitamin D treatment. At present, vitamin D deficiency can only be considered a cardiovascular risk marker, as vitamin D supplementation with doses recommended for osteoporosis treatment is neither proven to be beneficial nor harmful in cardiovascular diseases.


Assuntos
Doenças Cardiovasculares/etiologia , Doenças Cardiovasculares/fisiopatologia , Deficiência de Vitamina D/fisiopatologia , Vitamina D/fisiologia , Animais , Aterosclerose/epidemiologia , Aterosclerose/genética , Aterosclerose/metabolismo , Cálcio/metabolismo , Doenças Cardiovasculares/epidemiologia , Transtornos Cerebrovasculares/epidemiologia , Transtornos Cerebrovasculares/genética , Transtornos Cerebrovasculares/metabolismo , Suplementos Nutricionais , Insuficiência Cardíaca/epidemiologia , Insuficiência Cardíaca/genética , Insuficiência Cardíaca/metabolismo , Humanos , Prevalência , Fatores de Risco , Luz Solar , Vitamina D/genética , Vitamina D/metabolismo , Vitamina D/toxicidade , Deficiência de Vitamina D/epidemiologia , Deficiência de Vitamina D/genética , Vitaminas/metabolismo , Vitaminas/toxicidade
14.
Med Hypotheses ; 80(6): 750-5, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23566657

RESUMO

An argument is put forward for environmental modulators of photolabile or photosynthetic vitamins mediating autism risk via a complex downstream interaction of genetic/epigenetic phenomena that provide an explanation for seasonality in this and other developmentally originated disorders.


Assuntos
Transtornos Globais do Desenvolvimento Infantil/etiologia , Modelos Biológicos , Efeitos Tardios da Exposição Pré-Natal/induzido quimicamente , Estações do Ano , Raios Ultravioleta/efeitos adversos , Vitaminas/efeitos da radiação , /efeitos adversos , Feminino , Ácido Fólico/metabolismo , Humanos , Metilenotetra-Hidrofolato Redutase (NADPH2)/metabolismo , Gravidez , Vitaminas/toxicidade
15.
Plant Biotechnol J ; 10(9): 1026-34, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22928600

RESUMO

Multivitamin corn is a novel genetically engineered variety that simultaneously produces high levels of ß-carotene, ascorbate and folate, and therefore has the potential to address simultaneously multiple micronutrient deficiencies caused by the lack of vitamins A, B9 and C in developing country populations. As part of the development process for genetically engineered crops and following European Food Safety Authority (EFSA) recommendations, multivitamin corn must be tested in whole food/feed sub-chronic animal feeding studies to ensure there are no adverse effects, and potential allergens must be identified. We carried out a 28-day toxicity assessment in mice, which showed no short-term sub-acute evidence of diet-related adverse health effects and no difference in clinical markers (food consumption, body weight, organ/tissue weight, haematological and biochemical blood parameters and histopathology) compared to mice fed on a control diet. A subsequent 90-day sub-chronic feeding study again showed no indications of toxicity compared to mice fed on control diets. Our data confirm that diets enriched with multivitamin corn have no adverse effects on mice, do not induce any clinical signs of toxicity and do not contain known allergens.


Assuntos
Plantas Geneticamente Modificadas/toxicidade , Vitaminas/administração & dosagem , Zea mays/toxicidade , Animais , Feminino , Masculino , Camundongos , Testes de Toxicidade Subaguda , Testes de Toxicidade Subcrônica , Vitaminas/toxicidade
16.
Pharmacotherapy ; 32(4): 354-82, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22461123

RESUMO

The use of vitamin D supplements to prevent and treat a wide range of illnesses has increased substantially over the last decade. Epidemiologic evidence links vitamin D deficiency to autoimmune disease, cancer, cardiovascular disease, depression, dementia, infectious diseases, musculoskeletal decline, and more. The Institute of Medicine published an exhaustive report in 2010 that concluded that vitamin D supplementation for indications other than musculoskeletal health was not adequately supported by evidence and that most North Americans receive sufficient vitamin D from their diet and sun exposure. These conclusions are at odds with some clinical practice guidelines; thus, we sought to summarize the best available evidence regarding the benefits of vitamin D supplementation, to examine the potential risks, and to provide practical dosing advice. The adequacy of vitamin D stores is determined by measuring the 25-hydroxyvitamin D serum concentrations. The demarcations between deficiency (< 20 ng/ml), insufficiency (20-30 ng/ml), and optimal (30-80 ng/ml) serum concentrations are controversial. Vitamin D in doses of 800-5000 IU/day improve musculoskeletal health (e.g., reduces the rate of fractures and falls in older adults (aged ≥ 65 yrs). In patients with documented vitamin D deficiency, a cumulative dose of at least 600,000 IU administered over several weeks appears to be necessary to replenish vitamin D stores. Single large doses of 300,000-500,000 IU should be avoided. Vitamin D supplementation should not be offered routinely to other patient populations. Although results from some prospective clinical trials are promising, most have not been robustly designed and executed. The decision by young, otherwise healthy adults to take vitamin D in doses of 2000 IU/day or lower is unlikely to cause harm. For patients who are not at risk for developing vitamin D deficiency, sensible sun exposure is an inexpensive and enjoyable way to maintain vitamin D stores.


Assuntos
Suplementos Nutricionais , Vitamina D/uso terapêutico , Vitaminas/uso terapêutico , Animais , Doenças Ósseas/etiologia , Doenças Ósseas/prevenção & controle , Doenças Cardiovasculares/prevenção & controle , Humanos , Controle de Infecções , Neoplasias/prevenção & controle , Doenças do Sistema Nervoso/prevenção & controle , Doenças Respiratórias/prevenção & controle , Vitamina D/efeitos adversos , Vitamina D/fisiologia , Vitamina D/toxicidade , Deficiência de Vitamina D/tratamento farmacológico , Vitaminas/efeitos adversos , Vitaminas/fisiologia , Vitaminas/toxicidade
17.
Brain Res Bull ; 86(3-4): 246-53, 2011 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-21856383

RESUMO

Vitamin A supplementation among women is a common habit worldwide in an attempt to slow aging progression due to the antioxidant potential attributed to retinoids. Nonetheless, vitamin A elicits a myriad of side effects that result from either therapeutic or inadvertent intake at varying doses for different periods. The mechanism behind such effects remains to be elucidated. In this regard, we performed the present work aiming to investigate the effects of vitamin A supplementation at 100, 200, or 500IU/kgday(-1) for 2 months on female rat brain, analyzing tissue lipid peroxidation levels, antioxidant enzyme activities (both Cu/Zn-superoxide dismutase - SOD - and Mn-SOD); glutathione S-transferase (GST) and monoamine oxidase (MAO) enzyme activity; mitochondrial respiratory chain activity and redox parameters in mitochondrial membranes, as well as quantifying α- and ß-synucleins, ß-amyloid peptide(1-40), immunoglobulin heavy-chain binding protein/78kDa glucose-regulated protein (BiP/GRP78), receptor for advanced glycation end products (RAGE), D2 receptor, and tumor necrosis factor-α (TNF-α) contents in rat frontal cortex, hippocampus, striatum, and cerebellum. We observed increased lipid peroxidation marker levels, altered Cu/Zn-SOD and Mn-SOD enzyme activities, mitochondrial nitrosative stress, and impaired respiratory chain activity in such brain regions. On the other hand, we did not find any change in MAO and GST enzyme activities, and on α- and ß-synucleins, ß-amyloid peptide(1-40), GRP78/BiP, RAGE, D2 receptor, and TNF-α contents. Importantly, we did not observed any evidence regarding an antioxidant effect of such vitamin at low doses in this experimental model. The use of vitamin A as an antioxidant therapy among women needs to be reexamined.


Assuntos
Química Encefálica/efeitos dos fármacos , Doenças Mitocondriais/induzido quimicamente , Membranas Mitocondriais/metabolismo , Tirosina/análogos & derivados , Vitamina A/toxicidade , Vitaminas/toxicidade , Peptídeos beta-Amiloides/metabolismo , Animais , Antioxidantes/metabolismo , Transporte de Elétrons/fisiologia , Ensaio de Imunoadsorção Enzimática , Ciclo Estral/fisiologia , Feminino , Produtos Finais de Glicação Avançada/metabolismo , Monoaminoxidase/metabolismo , Estresse Oxidativo/fisiologia , Ratos , Ratos Wistar , Receptores de Dopamina D2/metabolismo , Succinato Desidrogenase/metabolismo , Superóxido Dismutase/metabolismo , Sinucleínas/metabolismo , Substâncias Reativas com Ácido Tiobarbitúrico/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Tirosina/metabolismo , Ubiquinona/metabolismo
18.
Alcohol Clin Exp Res ; 35(9): 1644-61, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21554333

RESUMO

BACKGROUND: Microphthalmia (reduced eye size), generally accompanied by vision defects, is a hallmark of fetal alcohol spectrum disorder (FASD) in humans. In zebrafish, embryonic ethanol exposure over the time of retinal neurogenesis also results in microphthalmia. This microphthalmia is in part the consequence of reduced retinal cell differentiation, including photoreceptors. Here we pursue 2 signaling pathways implicated in other aspects of FASD pathogenesis: retinoic acid (RA) and Sonic hedgehog (Shh). METHODS: We evaluated markers for RA and Shh signaling within the eyes of embryos treated with ethanol during the period of retinal neurogenesis. We also performed rescue experiments using administration of exogenous RA and microinjection of cholesterol, which augments Shh signaling. RESULTS: Using sequential or co-treatments, RA did not rescue ethanol-induced microphthalmia at any concentration tested. In addition, RA itself caused microphthalmia, although the underlying mechanisms were distinct from those of ethanol. Interestingly, RA treatment appeared to recover photoreceptor differentiation in a concentration-dependent manner. This may be an independent effect of exogenous RA, as ethanol treatment alone did not alter RA signaling in the eye. Cholesterol injection also did not rescue ethanol-induced microphthalmia at any concentration tested, and ethanol treatments did not alter expression of shh, or of ptc-2, which is normally regulated by Shh signaling. CONCLUSIONS: Together these findings indicate that, during the time of retinal neurogenesis, effects of ethanol on eye development are likely independent of the RA and Shh signaling pathways. These studies suggest that FASD intervention strategies based upon augmentation of RA or Shh signaling may not prevent ethanol-induced microphthalmia.


Assuntos
Depressores do Sistema Nervoso Central/toxicidade , Etanol/toxicidade , Proteínas Hedgehog/metabolismo , Microftalmia/induzido quimicamente , Neurogênese , Retina/embriologia , Tretinoína/metabolismo , Anormalidades Induzidas por Medicamentos/metabolismo , Anormalidades Induzidas por Medicamentos/patologia , Laranja de Acridina/metabolismo , Animais , Relação Dose-Resposta a Droga , Embrião não Mamífero/efeitos dos fármacos , Embrião não Mamífero/metabolismo , Feminino , Microftalmia/metabolismo , Microftalmia/patologia , Retina/metabolismo , Retina/patologia , Transdução de Sinais/efeitos dos fármacos , Transgenes , Tretinoína/farmacologia , Tretinoína/toxicidade , Vitaminas/metabolismo , Vitaminas/farmacologia , Vitaminas/toxicidade , Peixe-Zebra/embriologia , Peixe-Zebra/genética , Peixe-Zebra/metabolismo
19.
Basic Clin Pharmacol Toxicol ; 107(3): 703-8, 2010 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-20406210

RESUMO

Concurrent administration of chloramphenicol (CAP) with multivitamin-haematinics complex (MHC) is a common practice to cushioning anticipated anaemic effect of CAP in most developing countries. This study investigated the mechanism involved in CAP-induced reproductive toxicity as well as the effects of its co-administration with MHC in male rats. CAP and MHC were administered orally at therapeutic doses of 28 mg/kg body-weight and 0.08 ml/kg body-weight, respectively, every 6 hr for 10 days. After exposure, while there was body-weight loss in CAP, MHC and CAP plus MHC-treated animals, there were no treatment-related changes in the absolute and relative weights of the testes in all treated groups. Alone, MHC treatment markedly decreased catalase (CAT), glutathione S-transferase (GST), and 5' nucleotidase (5' NTD) activities whereas it resulted in significant increase in superoxide dismutase (SOD) activity. Activities of SOD, CAT and GST as well as H(2)O(2) levels were not significantly affected in CAP and CAP plus MHC-treated rats whereas GSH level and 5' NTD activity were markedly decreased in CAP plus MHC-treated rats. Significant increase in testicular alkaline phosphatase activity, lipid peroxidation and sperm abnormalities were accompanied by reduction in epididymal sperm number, sperm motility and live-dead ratio in all treatment groups whereas aminotransferase activities were unaffected. Treatment-related degeneration of the testes was evident in all treated animals. In summary, while MHC-induced testicular toxicity via oxidative stress, CAP did not and their combination is implicated in reproductive dysfunction within the time course of our investigation.


Assuntos
Antibacterianos/toxicidade , Cloranfenicol/toxicidade , Hematínicos/toxicidade , Reprodução/efeitos dos fármacos , Vitaminas/toxicidade , 5'-Nucleotidase/metabolismo , Animais , Antibacterianos/administração & dosagem , Peso Corporal/efeitos dos fármacos , Catalase/metabolismo , Cloranfenicol/administração & dosagem , Relação Dose-Resposta a Droga , Combinação de Medicamentos , Interações Medicamentosas , Glutationa Transferase/metabolismo , Hematínicos/administração & dosagem , Peroxidação de Lipídeos/efeitos dos fármacos , Masculino , Tamanho do Órgão/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Ratos , Ratos Wistar , Contagem de Espermatozoides , Motilidade dos Espermatozoides/efeitos dos fármacos , Espermatozoides/efeitos dos fármacos , Superóxido Dismutase/metabolismo , Testículo/efeitos dos fármacos , Testículo/patologia , Vitaminas/administração & dosagem
20.
Toxicol Mech Methods ; 20(2): 96-104, 2010 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-20100038

RESUMO

Excess hepatic iron generates reactive oxygen species that result in oxidative stress and oxidative damage to the liver. Vitamins have hitherto been considered to be a possible remedy. The aim of this study was to determine if high doses of delta-alpha-tocopherol supplementation in iron overload would ameliorate the oxidative stress. Four groups of 20 male Wistar albino rats were studied: group 1 (control) was fed normal diet, group 2 (Fe) 0.75% Ferrocene iron, group 3 (FV gp) 0.75% Ferrocene/delta-alpha-tocopherol (10x RDA), group 4 (V gp) normal diet/delta-alpha-tocopherol. After 12 months, serum iron, reduced glutathione, catalase, vitamin C, Oxygen Radical Absorbance Capacity, lipid peroxidation, 8-hydroxy-2'-deoxyguanosine (8-OHdG), aspartate transaminase (AST), and alanine transaminase (ALT) were measured. Vitamin C levels were: F gp = 5.04 +/- 0.09; FV gp = 5.85 +/- 0.13 (micromol/l) (p < 0.05). 8-hydroxy-2'-deoxyguanosine levels were: F gp = 143.6 +/- 6.4; FV gp = 179.2 +/- 18.2 (ng/ml) (p < 0.05). Oxidative liver damage, as determined by serum AST and ALT levels, was not attenuated by alpha-tocopherol. A positive correlation existed between vitamin C and 8-OHdG, suggesting possible delta-alpha-tocopherol toxicity.


Assuntos
Antioxidantes/toxicidade , Ácido Ascórbico/metabolismo , Desoxiguanosina/análogos & derivados , Sobrecarga de Ferro/induzido quimicamente , Fígado/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Vitaminas/toxicidade , alfa-Tocoferol/toxicidade , 8-Hidroxi-2'-Desoxiguanosina , Administração Oral , Alanina Transaminase/sangue , Animais , Antioxidantes/administração & dosagem , Ácido Ascórbico/sangue , Aspartato Aminotransferases/sangue , Biomarcadores/sangue , Catalase/sangue , Desoxiguanosina/metabolismo , Modelos Animais de Doenças , Compostos Ferrosos , Glutationa/sangue , Ferro/sangue , Sobrecarga de Ferro/metabolismo , Sobrecarga de Ferro/patologia , Peroxidação de Lipídeos/efeitos dos fármacos , Fígado/metabolismo , Fígado/patologia , Masculino , Metalocenos , Ratos , Ratos Wistar , Fatores de Tempo , Regulação para Cima , Vitaminas/administração & dosagem , alfa-Tocoferol/administração & dosagem
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