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1.
Nutrients ; 13(3)2021 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-33652684

RESUMO

Polycystic ovary syndrome (PCOS) is an increasingly common problem for women in the reproductive age throughout the entire world. A reduction diet with a low glycaemic index (GI) has proved to support the treatment of PCOS. The aim of the study was to analyse the influence of the diet on the level of vitamins soluble in water. The study included 55 women, 40 of which suffered from PCOS (identified by means of the Rotterdam Criteria) and 15 healthy women of the Caucasian race. The level of vitamins before and after the dietary intervention was measured. The diet was a reduction diet with a reduced glycaemic index (GI). Biochemical analyses were made on the basis of liquid chromatography-Infinity 1260 Binary liquid chromatography (LC) Agilent Technology. The level of vitamins in the serum was analysed together with the consumption before and after the dietary intervention. A higher level of vitamin C in the plasma was observed before and after the dietary intervention in the PCOS group in comparison to the control group despite the lower intake of this vitamin in the PCOS group. The remaining vitamins were at a comparable or lower level (B1, B3, B5, B6 and B12). After the dietary intervention, only B1 and B9 were at a clearly lower level (a trend of p = 0.093 and p = 0.085). A properly balanced reduction diet with reduced GI improves the supply of vitamins in women with PCOS. An additional recommendation should be the additional supplementation of B1, niacinamide and the combination of folates with inositol. The level of vitamin C in the plasma may not be a good marker of its supply in the PCOS group.


Assuntos
Deficiência de Vitaminas/dietoterapia , Dieta Redutora/métodos , Suplementos Nutricionais , Síndrome do Ovário Policístico/dietoterapia , Vitaminas/uso terapêutico , Adulto , Ácido Ascórbico/sangue , Deficiência de Vitaminas/sangue , Deficiência de Vitaminas/complicações , Feminino , Índice Glicêmico , Humanos , Síndrome do Ovário Policístico/sangue , Síndrome do Ovário Policístico/complicações , Resultado do Tratamento , Vitaminas/sangue
2.
J Infect Dev Ctries ; 15(2): 209-213, 2021 03 07.
Artigo em Inglês | MEDLINE | ID: mdl-33690202

RESUMO

INTRODUCTION: Coronavirus disease 2019 (COVID-19) is declared as pandemic by the World Health Orgnazation (WHO) on March 2020. One of the heavily utilized measures during this pandemic is vitamin C (aka ascorbic acid). Unfortunately, vitamin C has been associated with glucose measurement interference and thus this study highlights the elevated levels of blood glucose correlated with the presence of vitamin C interference. METHODOLOGY: Thirty samples were selected randomly and the blood glucose were measured prior and post the addition of spiked standard concentrations of vitamin C. The interference of vitamin C with glucose readings in COVID-19 pandemic were evaluated and observed employing the Auto Chemistry Analyzer machine. RESULTS: The addition of ascorbic acid (vitamin C) standards (spikes) into the isolated samples shows a correlated increment in the reading measures. Thereafter, the increments of Random Blood Sugar (RBS) readings after being spiked with the vitamin C standards shows a logarithmic correlation with good interesting R-squared (R2 = 0.9921). CONCLUSIONS: The authors find that the presence of vitamin C in blood actively and significantly alters the glucose level readings especially with the highly consumption of vitamin C during the COVID-19 pandemic.


Assuntos
Ácido Ascórbico/sangue , Glicemia/análise , Ácido Ascórbico/administração & dosagem , Humanos
3.
J Pharm Biomed Anal ; 196: 113927, 2021 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-33549875

RESUMO

To administer vitamin C (VC) with precision to patients with the coronavirus disease (COVID-19), we developed an ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method to assess plasma VC concentrations. 31 patients with COVID-19 and 51 healthy volunteers were enrolled. VC stability was evaluated in blood, plasma, and precipitant-containing stabilizers. A proportion of 7.7 % of VC was degraded in blood at room temperature (RT) (approximately 20-25 °C) at 1.5 h post administration with respect to the proportion degraded at 0.5 h, but without statistical difference. VC was stable in plasma for 0.75 h at RT, 2 h at 4 °C, 5 days at -40 °C, and 4 h in precipitant-containing stabilizer (2 % oxalic acid) at RT. The mean plasma concentration of VC in patients with COVID-19 was 2.00 mg/L (0.5-4.90) (n = 8), which was almost 5-fold lower than that in healthy volunteers (9.23 mg/L (3.09. 35.30)) (n = 51). After high-dose VC treatment, the mean VC concentration increased to 13.46 mg/L (3.93. 34.70) (n = 36), higher than that in healthy volunteers, and was within the normal range (6-20 mg/L). In summary, we developed a simple UPLC-MS/MS method to quantify VC in plasma, and determined the duration for which the sample remained stable. VC levels in patients with COVID-19 were considerably low, and supplementation at 100 mg/kg/day is considered highly essential.


Assuntos
Ácido Ascórbico/sangue , Ácido Ascórbico/farmacologia , /prevenção & controle , Adulto , Idoso , Cromatografia Líquida de Alta Pressão/métodos , Suplementos Nutricionais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Plasma/química , Valores de Referência , Espectrometria de Massas em Tandem/métodos , Adulto Jovem
4.
Neurosci Lett ; 740: 135425, 2021 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-33075422

RESUMO

Parkinson's disease (PD) is a neurodegenerative disease characterized by the progressive degeneration of dopaminergic neurons in the substantia nigra (SN). Oxidative stress has been identified as one of the major causes of nigrostriatal degeneration in PD. Ascorbic acid plays a role as an efficient antioxidant to protect cells from free radical damage, but it is easily oxidized and loses its antioxidant activity. To overcome this limitation, we have recently developed NXP031, a single-stranded DNA aptamer that binds to ascorbic acid with excellent specificity, reducing its oxidation and increasing its efficacy. This study investigated the neuroprotective effects of NXP031 in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD model. Acute degeneration of nigral dopaminergic neurons was induced by four consecutive treatments of MPTP (20 mg/kg) in male C57BL/6 J mice. NXP031 (Vitamin C/Aptamin C 200 mg/4 mg/kg) was administered intraperitoneally for 5 days following MPTP. We observed that the administration of NXP031 ameliorated MPTP-induced loss of dopaminergic neurons in the SN and exhibited improvement of MPTP-mediated motor impairment. We further found that NXP031 increased plasma ascorbic acid levels and inhibited microglia activation-induced neuroinflammation in the SN, which might contribute to the protective effects of NXP031 on nigrostriatal degeneration. Our findings suggest that NXP031 could be a potential therapeutic intervention in PD.


Assuntos
Intoxicação por MPTP/tratamento farmacológico , Fármacos Neuroprotetores/uso terapêutico , Doença de Parkinson Secundária/tratamento farmacológico , Animais , Ácido Ascórbico/sangue , Ácido Ascórbico/metabolismo , Neurônios Dopaminérgicos/efeitos dos fármacos , Neurônios Dopaminérgicos/patologia , Intoxicação por MPTP/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Microglia/patologia , Degeneração Neural/patologia , Doença de Parkinson Secundária/induzido quimicamente , Doença de Parkinson Secundária/patologia , Equilíbrio Postural/efeitos dos fármacos , Desempenho Psicomotor/efeitos dos fármacos , Substância Negra/patologia
5.
BMJ Case Rep ; 13(12)2020 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-33370932

RESUMO

A 58-year-old woman presented with a 1-week history of lower limb bruising. She had a medical history of recurrent metastatic colon cancer with a sigmoid colectomy and complete pelvic exenteration leading to colostomy and urostomy formation. She had malignant sacral mass encroaching on the spinal cord. This caused a left-sided foot drop for which she used an ankle-foot orthosis. She was on cetuximab and had received radiotherapy to the sacral mass 1 month ago. On examination, there were macular ecchymoses with petechiae on the lower limbs. There was sparing of areas that had been compressed by the ankle-foot orthosis. Bloods showed mild thrombocytopaenia and anaemia with markedly raised inflammatory markers. Coagulation studies consistent with inflammation rather than disseminated intravascular coagulation. She was found to have Klebsiella bacteraemia secondary to urinary source. Skin biopsy showed dermal haemorrhage without vessel inflammation. Vitamin C levels were low confirming the diagnosis of scurvy.


Assuntos
Ácido Ascórbico , Colectomia/efeitos adversos , Neoplasias Colorretais , Equimose , Desnutrição , Apoio Nutricional/métodos , Escorbuto , Antineoplásicos Imunológicos/uso terapêutico , Ácido Ascórbico/administração & dosagem , Ácido Ascórbico/sangue , Bacteriemia/diagnóstico , Bacteriemia/microbiologia , Colectomia/métodos , Neoplasias Colorretais/patologia , Neoplasias Colorretais/fisiopatologia , Neoplasias Colorretais/secundário , Neoplasias Colorretais/terapia , Diagnóstico Diferencial , Equimose/sangue , Equimose/diagnóstico , Equimose/etiologia , Feminino , Humanos , Klebsiella/isolamento & purificação , Extremidade Inferior , Desnutrição/etiologia , Desnutrição/terapia , Pessoa de Meia-Idade , Metástase Neoplásica , Estadiamento de Neoplasias , Exenteração Pélvica/efeitos adversos , Exenteração Pélvica/métodos , Escorbuto/sangue , Escorbuto/etiologia , Escorbuto/fisiopatologia , Escorbuto/terapia , Pele/patologia , Resultado do Tratamento , Vitaminas/administração & dosagem
7.
BMJ ; 370: m2194, 2020 07 08.
Artigo em Inglês | MEDLINE | ID: mdl-32641421

RESUMO

OBJECTIVE: To investigate the association of plasma vitamin C and carotenoids, as indicators of fruit and vegetable intake, with the risk of type 2 diabetes. DESIGN: Prospective case-cohort study. SETTING: Populations from eight European countries. PARTICIPANTS: 9754 participants with incident type 2 diabetes, and a subcohort of 13 662 individuals from the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort of 340 234 participants: EPIC-InterAct case-cohort study. MAIN OUTCOME MEASURE: Incident type 2 diabetes. RESULTS: In a multivariable adjusted model, higher plasma vitamin C was associated with a lower risk of developing type 2 diabetes (hazard ratio per standard deviation 0.82, 95% confidence interval 0.76 to 0.89). A similar inverse association was shown for total carotenoids (hazard ratio per standard deviation 0.75, 0.68 to 0.82). A composite biomarker score (split into five equal groups), comprising vitamin C and individual carotenoids, was inversely associated with type 2 diabetes with hazard ratios 0.77, 0.66, 0.59, and 0.50 for groups 2-5 compared with group 1 (the lowest group). Self-reported median fruit and vegetable intake was 274 g/day, 396 g/day, and 508 g/day for participants in categories defined by groups 1, 3, and 5 of the composite biomarker score, respectively. One standard deviation difference in the composite biomarker score, equivalent to a 66 (95% confidence interval 61 to 71) g/day difference in total fruit and vegetable intake, was associated with a hazard ratio of 0.75 (0.67 to 0.83). This would be equivalent to an absolute risk reduction of 0.95 per 1000 person years of follow up if achieved across an entire population with the characteristics of the eight European countries included in this analysis. CONCLUSIONS: These findings indicate an inverse association between plasma vitamin C, carotenoids, and their composite biomarker score, and incident type 2 diabetes in different European countries. These biomarkers are objective indicators of fruit and vegetable consumption, and suggest that diets rich in even modestly higher fruit and vegetable consumption could help to prevent development of type 2 diabetes.


Assuntos
Ácido Ascórbico/sangue , Carotenoides/sangue , Diabetes Mellitus Tipo 2/prevenção & controle , Frutas , Verduras , Biomarcadores/sangue , Estudos de Casos e Controles , Diabetes Mellitus Tipo 2/sangue , Dieta , Europa (Continente) , Feminino , Humanos , Masculino , Estudos Prospectivos
8.
BMC Psychiatry ; 20(1): 315, 2020 06 18.
Artigo em Inglês | MEDLINE | ID: mdl-32552785

RESUMO

BACKGROUND: Vitamin C deficiency may be more common than is generally assumed, and the association between vitamin C deficiency and adverse psychiatric effects has been known for centuries. This paper aims to systematically review the evidence base for the neuropsychiatric effects of vitamin C deficiency. METHODS: Relevant studies were identified via systematic literature review. RESULTS: Nine studies of vitamin C deficiency, including subjects both with and without the associated physical manifestations of scurvy, were included in this review. Vitamin C deficiency, including scurvy, has been linked to depression and cognitive impairment. No effect on affective or non-affective psychosis was identified. CONCLUSIONS: Disparate measurement techniques for vitamin C, and differing definitions of vitamin C deficiency were apparent, complicating comparisons between studies. However, there is evidence suggesting that vitamin C deficiency is related to adverse mood and cognitive effects. The vitamin C blood levels associated with depression and cognitive impairment are higher than those implicated in clinical manifestations of scurvy. While laboratory testing for ascorbic acid can be practically difficult, these findings nonetheless suggest that mental health clinicians should be alerted to the possibility of vitamin C deficiency in patients with depression or cognitive impairment. Vitamin C replacement is inexpensive and easy to deliver, although as of yet there are no outcome studies investigating the neuropsychiatric impact of vitamin C replacement in those who are deficient.


Assuntos
Deficiência de Ácido Ascórbico/complicações , Deficiência de Ácido Ascórbico/psicologia , Disfunção Cognitiva/etiologia , Ácido Ascórbico/sangue , Deficiência de Ácido Ascórbico/sangue , Deficiência de Ácido Ascórbico/fisiopatologia , Disfunção Cognitiva/sangue , Disfunção Cognitiva/fisiopatologia , Disfunção Cognitiva/psicologia , Depressão/sangue , Depressão/complicações , Depressão/fisiopatologia , Depressão/psicologia , Humanos , Escorbuto/sangue , Escorbuto/complicações , Vitaminas/sangue
9.
Cardiovasc Ther ; 2020: 4940673, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32426036

RESUMO

Background: Hypertension is regarded as a major and independent risk factor of cardiovascular diseases, and numerous studies observed an inverse correlation between vitamin C intake and blood pressure. Aim: Our aim is to investigate the relationship between serum vitamin C and blood pressure, including the concentration differences and the correlation strength. Method: Two independent researchers searched and screened articles from the National Library of Medicine, Cochrane Library, Web of Science, China National Knowledge Infrastructure, VIP databases, and WANFANG databases. A total of 18 eligible studies were analyzed in the Reviewer Manager 5.3 software, including 14 English articles and 4 Chinese articles. Results: In the evaluation of serum vitamin C levels, the concentration in hypertensive subjects is 15.13 µmol/L lower than the normotensive ones (mean difference = -15.13, 95% CI [-24.19, -6.06], and P = 0.001). Serum vitamin C has a significant inverse relation with both systolic blood pressure (Fisher's Z = -0.17, 95% CI [-0.20, -0.15], P < 0.00001) and diastolic blood pressure (Fisher's Z = -0.15, 95% CI [-0.20, -0.10], P < 0.00001). Conclusions: People with hypertension have a relatively low serum vitamin C, and vitamin C is inversely associated with both systolic blood pressure and diastolic blood pressure.


Assuntos
Ácido Ascórbico/sangue , Pressão Sanguínea , Hipertensão/fisiopatologia , Deficiência de Vitamina D/sangue , Adulto , Idoso , Idoso de 80 Anos ou mais , Biomarcadores/sangue , Feminino , Humanos , Hipertensão/diagnóstico , Hipertensão/epidemiologia , Masculino , Pessoa de Meia-Idade , Estudos Observacionais como Assunto , Medição de Risco , Fatores de Risco , Deficiência de Vitamina D/diagnóstico , Deficiência de Vitamina D/epidemiologia , Adulto Jovem
10.
Am J Respir Crit Care Med ; 202(5): 700-707, 2020 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-32396775

RESUMO

Rationale: Whether biomarkers can identify subgroups of patients with septic shock with differential treatment responses to hydrocortisone is unknown.Objectives: To determine if there is heterogeneity in effect for hydrocortisone on mortality, shock resolution, and other clinical outcomes based on baseline cortisol, aldosterone, and ascorbic acid concentrations.Methods: From May 2014 to April 2017, we obtained serum samples from 529 patients with septic shock from 22 ICUs in Australia and New Zealand.Measurements and Main Results: There were no significant interactions between the association with 90-day mortality and treatment with either hydrocortisone or placebo for total cortisol (odds ratio [OR], 1.09; 95% confidence interval [CI], 1.02-1.16 vs. OR, 1.07; 95% CI, 1.00-1.13; P = 0.70), free cortisol (OR, 1.20; 95% CI, 1.04-1.38 vs. OR, 1.16; 95% CI, 1.02-1.32; P = 0.75), aldosterone (OR, 1.01; 95% CI, 0.97-1.05 vs. OR, 1.01; 95% CI, 0.98-1.04; P = 0.99), or ascorbic acid (OR, 1.11; 95% CI, 0.89-1.39 vs. OR, 1.05; 95% CI, 0.91-1.22; P = 0.70), respectively. Similar results were observed for the association with shock resolution. Elevated free cortisol was significantly associated with 90-day mortality (OR, 1.13; 95% CI, 1.00-1.27; P = 0.04), but total cortisol, aldosterone, and ascorbic acid were not.Conclusions: In patients with septic shock, there was no heterogeneity in effect of adjunctive hydrocortisone on mortality, shock resolution, or other clinical outcomes based on cortisol, aldosterone, and ascorbic acid concentrations. Plasma aldosterone and ascorbic acid concentrations are not associated with outcome.


Assuntos
Aldosterona/sangue , Ácido Ascórbico/sangue , Hidrocortisona/farmacocinética , Choque Séptico/tratamento farmacológico , Idoso , Anti-Inflamatórios/farmacocinética , Austrália/epidemiologia , Biomarcadores/sangue , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Nova Zelândia/epidemiologia , Estudos Retrospectivos , Índice de Gravidade de Doença , Choque Séptico/sangue , Choque Séptico/mortalidade , Taxa de Sobrevida/tendências , Resultado do Tratamento
11.
Arch Med Res ; 51(3): 204-214, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32111490

RESUMO

BACKGROUND: Oxidative and endoplasmic reticulum stresses contribute to the pathogenesis of ß-cell dysfunction in diabetes mellitus. This study investigates the effect of isopulegol on the above stresses in HFD/STZ induced diabetic rats. METHODS: Animals in group I and II were placed in normal pellet diet and group II was treated with isopulegol at 200 mg/kg b.w. Animals in groups III-V were placed in HFD for 4 weeks and made diabetic with single intraperitoneal injection of STZ (35 mg/kg b.w) in 0.1 M citrate buffer (pH 4.5). Group III served as diabetic control while animals in group IV and V were treated with isopulegol (100 mg/kg b.w) and metformin (25 mg/kg b.w) respectively for 28 d. RESULTS: The activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione sulphur transferase (GST), glutathione reductase (GR) and the levels of vitamin-E, vitamin-C, reduced glutathione (GSH) were significantly (p <0.05) decreased in plasma and tissues of diabetic rats. Thiobarbituric acid reactive acid substances (TBARS) and lipid hydroperoxides (LHP), indices of lipid peroxidation were also significantly (p <0.05) increased in diabetic rats. In pancreatic tissue ER stress markers PERK, elf2α, ATF4 and in hepatic tissue oxidative stress marker UCP-2 expression was significantly (p <1.0) increased in diabetic rats. Administration of isopulegol significantly improved antioxidant status and decreased oxidative and ER stress markers in diabetic treated rats. Histopathological studies on liver and kidney supported the above findings. The results are comparable with the standard drug metformin. CONCLUSIONS: Isopulegol a naturally occurring monoterpene alcohol attenuated oxidative and ER stress in HFD/STZ induced diabetic rats.


Assuntos
Antioxidantes/farmacologia , Monoterpenos Cicloexânicos/farmacologia , Diabetes Mellitus Experimental/tratamento farmacológico , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Hipoglicemiantes/farmacologia , Estresse Oxidativo/efeitos dos fármacos , Animais , Ácido Ascórbico/sangue , Glicemia/metabolismo , Catalase/metabolismo , Glutationa/sangue , Glutationa Peroxidase/metabolismo , Glutationa Redutase/metabolismo , Glutationa Transferase/metabolismo , Hiperglicemia/patologia , Insulina/sangue , Peroxidação de Lipídeos/efeitos dos fármacos , Peróxidos Lipídicos/sangue , Masculino , Ratos , Ratos Wistar , Estreptozocina , Superóxido Dismutase/metabolismo , Substâncias Reativas com Ácido Tiobarbitúrico/análise , Vitamina E/sangue
12.
BMJ Case Rep ; 13(3)2020 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-32139451

RESUMO

A 66-year-old Caucasian woman was admitted with deteriorating mental health in the setting of background history of schizophrenia and depression. Her husband reported that she had increasing negative thoughts and decreased motivation regarding her self-care over a few weeks with no obvious stressors. Initial laboratory tests were unremarkable except for isolated normocytic anaemia. Physical examination revealed widespread bilateral upper limb ecchymoses and lower limb petechial rash. After an extensive investigation with no definitive results to explain her clinical presentations, diagnosis of scurvy was suspected and confirmed with severely low serum vitamin C level. Her clinical symptoms improved markedly with oral supplementation, which further supported the diagnosis of scurvy. Although it is now a rare condition in developed countries, this case will remind modern medical practitioners that patients with scurvy may present with non-specific symptoms and clinical findings such as depression and anaemia.


Assuntos
Anemia/etiologia , Ácido Ascórbico/uso terapêutico , Depressão/etiologia , Escorbuto/complicações , Idoso , Ácido Ascórbico/sangue , Feminino , Humanos , Escorbuto/tratamento farmacológico
13.
PLoS One ; 15(2): e0229002, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32059045

RESUMO

BACKGROUND: Although protective associations between dietary antioxidants and pregnancy outcomes have been reported, randomized controlled trials of supplementation have been almost uniformly negative. A possible explanation is that supplementation during pregnancy may be too late to have a beneficial effect. Therefore, we examined the relationship between antioxidant levels prior to pregnancy and birth outcomes. METHODS AND FINDINGS: Serum carotenoids and tocopherols were assayed in fasting specimens at 1985-86 (baseline) and 1992-1993 (year 7) from 1,215 participants in Coronary Artery Risk Development in Young Adults (CARDIA) study. An interviewer-administered quantitative food-frequency questionnaire assessed dietary intake of antioxidants. Pregnancy outcome was self-reported at exams every 2 to 5 years. Linear and logistic regression modeling was used to assess relationships of low birthweight (LBW; <2,500 g), continuous infant birthweight, preterm birth (PTB; <37 weeks) and length of gestation with antioxidant levels adjusted for confounders, as well as interactions with age and race. RESULTS: In adjusted models, lycopene was associated with higher odds of LBW (adjusted odds ratio for top quartile, 2.15, 95% confidence interval 1.14, 3.92) and shorter gestational age (adjusted beta coefficient -0.50 weeks). Dietary intake of antioxidants was associated with lower birthweight, while supplement use of vitamin C was associated with higher gestational age (0.41 weeks, 0.01, 0.81). CONCLUSIONS: Higher preconception antioxidant levels are not associated with better birth outcomes.


Assuntos
Afro-Americanos , Antioxidantes/metabolismo , Ácido Ascórbico/sangue , Carotenoides/sangue , Grupo com Ancestrais do Continente Europeu , Idade Gestacional , Nascimento Prematuro/sangue , Adolescente , Adulto , Feminino , Humanos , Recém-Nascido de Baixo Peso , Recém-Nascido , Gravidez , Adulto Jovem
14.
Mikrochim Acta ; 187(1): 82, 2020 01 02.
Artigo em Inglês | MEDLINE | ID: mdl-31897862

RESUMO

An electrochemical sensor is described for the simultaneous voltammetric determination of ascorbic acid (AA), dopamine (DA), and uric acid (UA). An indium-tin oxide (ITO) electrode was modified with a hierarchical core-shell metal-organic framework and Ag-doped mesoporous metal-oxide based hybrid nanocomposites on g-C3N4 nanosheets. The morphology, structural and chemical composition of the hybrid nanocomposite was characterized using different analytical methods. The modified ITO showed superior electrocatalytic performance towards the oxidation of AA, DA and UA due to the enhanced surface area, synergistic effects and well-organized porous assembly. Figures of merit, include (a) linear responses from 0.1 to 200 µM, 2.5 to 100 µM and 2.5 to 625 µM; (b) detection limits (at S/N = 3) of 0.02, 0.01 and 0.06 µM, and (c) well separated oxidation peaks near -50, 186 and 390 mV (vs. Ag/AgCl) for simultaneous sensing AA, DA and UA, respectively. The sensor was evaluated by analysing spiked serum samples and gave data with precision, with recoveries of >98%. Graphical abstractSchematic Representation of a Mesoporous Silver-doped TiO2-SnO2 Nanocomposite (h-ATS) on g-C3N4 Nanosheets and Decorated with a Hierarchical Core-Shell Metal-Organic Framework (NC@GC) Based Electrochemical Sensor for Simultaneous Voltammetric Detection of Ascorbic acid, Dopamine and Uric acid.


Assuntos
Ácido Ascórbico/análise , Dopamina/análise , Eletroquímica/métodos , Estruturas Metalorgânicas/química , Nanocompostos/química , Nanoestruturas/química , Ácido Úrico/análise , Ácido Ascórbico/sangue , Dopamina/sangue , Eletroquímica/normas , Eletrodos , Grafite/química , Compostos de Nitrogênio/química , Prata , Compostos de Estanho , Titânio , Ácido Úrico/sangue
15.
Mikrochim Acta ; 187(2): 136, 2020 01 17.
Artigo em Inglês | MEDLINE | ID: mdl-31953607

RESUMO

A two-dimensional zinc(II)-based metal-organic framework [Zn • (BA) • (BBI)] was synthesized from 1,2-benzenediacetic acid and 1,1'-(1,4-butanediyl) bis(imidazole) via a solvothermal reaction. The crystal exhibits good chemical stability in the pH range from 2 to 12, and strong fluorescence with excitation/emission maxima of 270/290 nm. The crystal is shown to by a viable fluorescent probe for the detection of ascorbic acid (AA) and the antibiotics chloramphenicol (CHL) and ceftriaxone (CRO). Fluorescence intensity of crystal dispersion is significantly quenched with increasing concentrations of AA/CHL/CRO. Quenching occurs even in the presence of other substances. The assay is fast (5 s) and has a low detection limit (1.6 ppb for AA, 12 ppb for CHL and 3.9 ppb for CRO). The crystal still has a good quenching effect on AA/CHL/CRO after washing and using for five times. The response of the probe is related to the interplay between the MOF and analytes via energy absorption competition. Graphical abstractSchematic diagram of preparing Zn • (BA) • (BBI) and responding to target analytes. BA: 1,2-phenyldiacetic acid; BBI: 1,1'-(1,4-butanediyl)bis(imidazole); Zn • (BA) • (BBI): Crystal chemical formula.


Assuntos
Ácido Ascórbico/sangue , Ceftriaxona/sangue , Cloranfenicol/sangue , Corantes Fluorescentes/química , Estruturas Metalorgânicas/química , Animais , Antibacterianos/sangue , Cabras , Limite de Detecção , Espectrometria de Fluorescência/métodos , Zinco/química
16.
Mikrochim Acta ; 187(2): 149, 2020 01 27.
Artigo em Inglês | MEDLINE | ID: mdl-31989275

RESUMO

Two-dimensional porous graphitic carbon nitride (g-C3N4) nanosheets were synthesized by low-cost and direct thermal oxidation. Porous g-C3N4 assembled with graphene oxide (GO) was immobilized on a glassy carbon electrode. The sensor was applied to simultaneous determination of ascorbic acid (AA), dopamine (DA) and uric acid (UA) with high performance. Cyclic voltammetry and differential pulse voltammetry were used to investigate electrochemical and electrocatalytic properties. The results indicate that the electrochemical sensor possesses high specific surface area, hierarchical pore structure and excellent signal response to AA, DA and UA. The oxidation potentials are well separated at around 0.15, 0.34 and 0.46 V for AA, DA and UA respectively. The determination limits for AA, DA and UA are 3.7 µM, 0.07 µM and 0.43 µM, respectively. The sensor was applied to tracking the three analytes in spiked serum samples with recovery 95.1~105.5% and relation standard deviations of less than 5%. Graphical abstract Schematic representation of porous graphitic carbon nitride nanosheet embedded in graphene oxide for simultaneous determination of ascorbic acid, dopamine and uric acid.


Assuntos
Ácido Ascórbico/sangue , Dopamina/sangue , Grafite/química , Nanoestruturas/química , Compostos de Nitrogênio/química , Ácido Úrico/sangue , Técnicas Eletroquímicas/instrumentação , Técnicas Eletroquímicas/métodos , Eletrodos , Humanos , Limite de Detecção , Reprodutibilidade dos Testes
17.
Diabetes ; 69(2): 238-248, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31740441

RESUMO

This study aims to model genetic, immunologic, metabolomics, and proteomic biomarkers for development of islet autoimmunity (IA) and progression to type 1 diabetes in a prospective high-risk cohort. We studied 67 children: 42 who developed IA (20 of 42 progressed to diabetes) and 25 control subjects matched for sex and age. Biomarkers were assessed at four time points: earliest available sample, just prior to IA, just after IA, and just prior to diabetes onset. Predictors of IA and progression to diabetes were identified across disparate sources using an integrative machine learning algorithm and optimization-based feature selection. Our integrative approach was predictive of IA (area under the receiver operating characteristic curve [AUC] 0.91) and progression to diabetes (AUC 0.92) based on standard cross-validation (CV). Among the strongest predictors of IA were change in serum ascorbate, 3-methyl-oxobutyrate, and the PTPN22 (rs2476601) polymorphism. Serum glucose, ADP fibrinogen, and mannose were among the strongest predictors of progression to diabetes. This proof-of-principle analysis is the first study to integrate large, diverse biomarker data sets into a limited number of features, highlighting differences in pathways leading to IA from those predicting progression to diabetes. Integrated models, if validated in independent populations, could provide novel clues concerning the pathways leading to IA and type 1 diabetes.


Assuntos
Diabetes Mellitus Tipo 1/imunologia , Difosfato de Adenosina/metabolismo , Adolescente , Ácido Ascórbico/sangue , Autoimunidade , Biomarcadores/sangue , Butiratos/sangue , Estudos de Casos e Controles , Criança , Pré-Escolar , Diabetes Mellitus Tipo 1/sangue , Feminino , Fibrinogênio/metabolismo , Humanos , Lactente , Masculino , Manose/sangue , Modelos Biológicos , Polimorfismo Genético , Proteína Tirosina Fosfatase não Receptora Tipo 22/genética , Adulto Jovem
18.
Appl Spectrosc ; 74(3): 275-284, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31617379

RESUMO

Ascorbic acid (AA), or vitamin C, is an important reactive biological molecule in vivo, and an abnormal level of AA is associated with many diseases. Therefore, the rapid, sensitive, and selective detection of AA levels is of significance in cases of medical assay and diagnosis. Compared with other nanoparticles, lanthanide coordination polymer nanoparticles (Ln-CPs) have been demonstrated as the excellent biomolecule sensing platforms due to their unique optical properties and intrinsic porosities. In this work, the cerium coordination polymer nanoparticles ATP-Ce-Tris were synthesized in a simple and quick way. The synthesized ATP-Ce-Tris nanoparticle shows the characteristic peak of Ce3+ located at 365 nm, which is corresponding to the 4f→5d transition of Ce3+. In the presence of Fe3+, the fluorescence of ATP-Ce-Tris quenched, and the following added ascorbic acid (AA) makes it restoring effectively. Based on this, we constructed a fluorescence probe with excellent sensitivity for AA sensing in a wide linear relationship from 0.05 to 500 µM. The detection limit was as low as 18 nM (signal-to-noise ratio of three), which is one or two orders of magnitude lower than those of reported sensors. The proposed sensing systems also exhibits excellent sensitivity for AA detection in human serum sample, exploiting a valuable platform for AA analysis in clinic diagnostic and drug screening.


Assuntos
Ácido Ascórbico/sangue , Técnicas Biossensoriais/métodos , Espectrometria de Fluorescência/métodos , Cério/química , Corantes Fluorescentes/síntese química , Humanos , Limite de Detecção , Nanopartículas/química , Polímeros/síntese química , Sensibilidade e Especificidade
19.
J. investig. allergol. clin. immunol ; 30(3): 182-190, 2020. tab, graf
Artigo em Inglês | IBECS | ID: ibc-195170

RESUMO

BACKGROUND: Treg cells and dietetic factors may play a significant role in the natural acquisition of tolerance in children with cow's milk allergy (CMA). The best marker for Treg lymphocytes is the transcription factor forkhead boxP3 (FOXP3). OBJECTIVE: We examine the relationship between FOXP3 mRNA expression and serum concentrations of vitamins D and C and the development of different phenotypes of tolerance in children with CMA. MATERIAL AND METHODS: The study group comprised 138 infants with CMA and 101 healthy infants. All children underwent oral food challenge, first with an extensively heated milk product and then with unheated products. FOXP3 mRNA expression and serum vitamin C and D concentrations were evaluated. RESULTS: At 2 years of life, 54 children (39.1%) still had CMA, 43 (31.2%) were unheated milk-reactive and heated milk-tolerant, while 41 (29.7%) had outgrown their allergy. The mean (SD) level of FOXP3 expression in the study group was 2.07 (1.23), which was lower than the control group value of 2.98 (1.52) (P<.001). A value below 1.45 indicated allergy. The mean serum level of vitamin D in the study group was lower than in the control group (29.67 [7.09] vs 33.35 [4.13] ng/mL; P<.001). No significant differences were found in mean serum vitamin C content. CONCLUSIONS: Increased FOXP3 mRNA expression can predict faster acquisition of tolerance in infants with CMA. These children have lower serum vitamin D levels than healthy children. No relationship was found between the natural history of CMA and serum vitamin C concentration


ANTECEDENTES: Las células Treg y los factores dietéticos pueden desempeñar un papel importante en la adquisición natural de tolerancia en niños con alergia a la leche de vaca (CMA). El mejor marcador de linfocitos Treg es el factor de transcripción Forkhead box P3 (FOXP3). OBJETIVOS: El artículo examina la relación entre la expresión de mRNA específico para FOXP3 y la concentración sérica de vitaminas D y C, así como el desarrollo de diferentes fenotipos de tolerancia en niños con CMA. Material y métodos: El grupo de estudio estaba compuesto por 138 bebés con CMA y 101 sanos. Todos los niños tomaron primero un producto lácteo hervido vía oral, y posteriormente productos lácteos sin calentar. Se evaluó la expresión de ARNm para FOXP3 y la concentración sérica de vitamina C y D. RESULTADOS: A los dos años de vida, 54 (39,1%) de los niños aún mostraban CMA, 43 (31,2%) eran reactivos a la leche sin calentar y tolerantes a la leche caliente, mientras que 41 (29,7%) habían superado la alergia. El nivel medio de expresión de FOXP3 en el grupo CMA fue de 2,07 ± 1,23; inferior al obtenido en el grupo control de 2,98 ± 1,52 (p < 0,001). Un valor por debajo de 1,45 indica alergia. El nivel sérico medio de vitamina D en el grupo de estudio (29,67 ± 7,09 ng/ml) fue más bajo que en el grupo control, 33,35 ± 4,13 ng/ml (p < 0,001). No se encontraron diferencias significativas en el contenido medio de vitamina C en suero. CONCLUSIONES: El aumento de la expresión de FOXP3 mRNA puede predecir la adquisición de tolerancia más rápida en los bebés con CMA. Estos niños tienen niveles séricos más bajos de vitamina D que los niños sanos. No se encontró relación entre la historia natural de CMA y la concentración de vitamina C en suero


Assuntos
Humanos , Masculino , Feminino , Lactente , Hipersensibilidade a Leite/sangue , Hipersensibilidade a Leite/genética , Fatores de Transcrição Forkhead/genética , RNA Mensageiro/genética , Ácido Ascórbico/sangue , Vitamina D/sangue , Expressão Gênica , Estudos de Casos e Controles , Fenótipo
20.
Nutrients ; 11(12)2019 Dec 04.
Artigo em Inglês | MEDLINE | ID: mdl-31817129

RESUMO

Vitamin C and antioxidants play a crucial role in endothelial function and may be a link for the known interaction of periodontitis and ischemic heart disease (CAD). This pilot study evaluates the association of gingival health, periodontitis, CAD, or both conditions with salivary and serum vitamin C and antioxidant levels. The clinical and periodontal characteristics, serum, and saliva samples were collected from 36 patients with periodontitis, 35 patients with CAD, 36 patients with periodontitis plus CAD, and 36 healthy controls. Levels of vitamin C, antioxidants, and C-reactive protein (hs-CRP) were assessed with a commercially available kit. The median concentrations of salivary and serum vitamin C and antioxidants (α-tocopherol, ß-carotene, lutein, and lycopene) were significantly lower in the CAD group (p < 0.001) and in the periodontitis plus CAD group (p < 0.001) compared to periodontitis patients and controls. In univariate models, periodontitis (p = 0.034), CAD (p < 0.001), and hs-CRP (p < 0.001) were significantly negatively associated with serum vitamin C; whereas, in a multivariate model, only hs-CRP remained a significant predictor of serum vitamin C (p < 0.001). In a multivariate model, the significant predictors of salivary vitamin C levels were triglycerides (p = 0.028) and hs-CRP (p < 0.001). Patients with CAD and periodontitis plus CAD presented lower levels of salivary and serum vitamin C compared to healthy subjects and periodontitis patients. hs-CRP was a significant predictor of decreased salivary and serum vitamin C levels.


Assuntos
Antioxidantes/análise , Ácido Ascórbico/análise , Isquemia Miocárdica , Periodontite , Saliva/química , Adulto , Ácido Ascórbico/sangue , Estudos de Casos e Controles , Humanos , Pessoa de Meia-Idade , Isquemia Miocárdica/sangue , Isquemia Miocárdica/complicações , Isquemia Miocárdica/epidemiologia , Periodontite/sangue , Periodontite/complicações , Periodontite/epidemiologia
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