Agentes quelantes sulfidrílicos: uma revisão

The increase industrial use of metais such as berilium, cadmium, copper, lead, magnesium and nickel results inevitably on a more contaminated environment. For this reason, environmental chronic poisonings with these metais have not been unusual and is a serious human health concern. Chelation therapy has been the basis for the medical treatment of metal poisoning for the past 4 decades. Chelating agents have been used clinically as antidotes for acute and chronic metal intoxications. These compounds enhance the excretion of toxic elements such as arsenic, cadmium, lead, or mercury, which are also well-known developmental toxicants. Moreover, they also decrease the metal's toxicity by preventing it from binding to cellular target molecules. However, there are many questions concerning the use of these compounds, including a wide range of overt and hidden undesirable side effects caused by these therapeutic dithiol chelating agents. The aspects pointed out above clearly indicate that more detailed experimental and clinical experiments are required to better establish the toxicological properties of BAL, DMPS and DMSA.O aumento do uso industrial de metais como o berílio, o cádmio, o cobre, o chumbo, o magnésio e o níquel inevitavelmente resultam em um ambiente mais contaminado. Por esta razão, as intoxicações ambientais crônicas não são raras e resultam em uma preocupação para a saúde humana. A terapia que utiliza os agentes quelantes tem sido a base do tratamento médico de intoxicações por metal desde a década de 40. Os agentes quelantes são utilizados clinicamente com antídotos para intoxicações agudas e crônicas por metal. Estes compostos atuam aumentando a excreção de elementos tóxicos, como o arsênio, o cádmio, o chumbo e o mercúrio os quais são bem conhecidos pela toxicidade que desenvolvem. Além disso, eles também diminuem a toxicidade do metal por prevenir a ligação destes a moléculas celulares alvo. Entretanto, existem muitas questões referentes à utilização terapêutica dos agentes quelantes ditiólicos, incluindo evidências de efeitos colaterais indesejáveis, ainda obscuras. Os aspectos expostos acima indicam claramente que experimentos mais detalhados e experimentos clínicos são necessários para melhor estabelecer as propriedades toxicológicas do BAL, DMPS e DMSA

Ações biológicas de compostos de selênio e telúrio: efeitos tóxicos sobre o sistema nervoso central

The biochemistry and pharmacology of selenium is a subject of intense current interest, particularly from the viewpoint of public health. Selenium, long recognized as a dietary oxidant, is now known to be an essential component of the active sites of several enzymes. In contrast to the case of selenium, surprisingly little is known of the occurrence of tellurium in biological systems. However, tellurium shares chemical characteristics with selenium. Taking into account, researches that focus on biological activities of selenium and tellurium are the greatest interest. These compounds are important intermediates in organic synthesis and present some pharmacological properties. Besides, selenium and tellurium can oxidize SH groups of proteins since they could be toxic to animais. Based in this property, some studies revealed that selenium and tellurium are potentially neurotoxic. In this way, this review point out toxic effects induced by selenium and tellurium organic compounds highlight the effects on central nervous system.A bioquímica e a farmacologia do selênio tem sido assunto de muito interesse, particularmente sob o ponto de vista de saúde pública. O selênio há muito tempo descrito como um antioxidante, e agora também conhecido por ser um componente essencial do sítio ativo de diversas enzimas. Ao contrário do selênio, pouco é conhecido sobre a ocorrência de telúrio em sistemas biológicos. Apesar de não apresentar função fisiológica descrita, o telúrio compartilha algumas peculiaridades químicas com o selênio. Neste contexto, pesquisas que revelam as ações biológicas de moléculas que contenham átomos de selênio e telúrio mostram-se de grande importância em virtude de suas aplicações como ferramentas sintéticas em química orgânica e de suas propriedades farmacológicas. Paralelo a isso, já se sabe que moléculas que contenham selênio e telúrio são capazes de reagir com grupos SH de proteínas biologicamente ativas. Com base nesta característica, estudos revelam que estes compostos são potencialmente tóxicos ao sistema nervoso central (SNC). Sendo assim, esta revisão aborda os efeitos tóxicos induzidos por compostos orgânicos de selênio e telúrio, com ênfase nos efeitos sobre o SNC

Locust bean gum nano-based hydrogel for vaginal delivery of diphenyl diselenide in the treatment of trichomoniasis : formulation characterization and in vitro biological evaluation

Trichomoniasis is the most common nonviral sexually transmitted infection in the world, but its available therapies present low efficacy and high toxicity. Diphenyl diselenide (PhSe2) is a pharmacologically active organic selenium compound; however, its clinical use is hindered by its lipophilicity and toxicity. Nanocarriers are an interesting approach to overcome the limitations associated with this compound. This study designed and evaluated a vaginal hydrogel containing PhSe2-loaded Eudragit® RS100 and coconut oil nanocapsules for the treatment of trichomoniasis. Nanocapsules presented particle sizes in the nanometric range, positive zeta potential, a compound content close to the theoretical value, and high encapsulation efficiency. The nanoencapsulation maintained the anti-Trichomonas vaginalis action of the compound while improving the scavenger action in a DPPH assay. The hydrogels were prepared by thickening nanocapsule suspensions with locust bean gum (3%). The semisolids maintained the nanometric size of the particles and the PhSe2 content at around the initial concentration (1.0 mg/g). They also displayed non-Newtonian pseudo-plastic behavior and a highly mucoadhesive property. The chorioallantoic membrane method indicated the absence of hemorrhage, coagulation, or lysis. The compound, from both non-encapsulated and nano-based hydrogel delivery systems, remained on the surface of the bovine vaginal mucosa. Therefore, the formulations displayed the intended properties and could be a promising alternative for the treatment of trichomoniasis

Diphenyl diselenide, a simple glutathione peroxidase mimetic, inhibits human LDL oxidation in vitro

Oxidative modification of low-density lipoprotein (LDL) represents an important factor in atherogenesis. In the present study, we have investigated the antioxidant capability of diphenyl diselenide (PhSe)2, a simple organoseleno compound, against copper (Cu2+) and peroxyl radical-induced human LDL oxidation in vitro. In initial studies using human serum, (PhSe)2 caused a dose-dependent inhibition of Cu2+-induced lipid peroxidation, which was correlated to thiol consumption. (PhSe)2 increased lipid peroxidation lag phase and decreased lipid peroxidation rate in isolated human LDL, evaluated by measuring both conjugated diene (CD) and thiobarbituric acid reactive substances (TBARS) levels. Consistent with these observations, (PhSe)2 showed a marked inhibitory effect on 2,2-azobis(2-amidinopropane dihydrochloride) (AAPH)-induced oxidation of LDL or parinaric acid (PnA) incorporated into LDL. (PhSe)2 also displayed a dose-dependent protective effect against Cu2+-induced lipid peroxidation in rat aortic slices. Interestingly, besides the antioxidant effects of (PhSe)2 toward the lipid moieties of LDL, which was related to its thiol-peroxidase activity, protein moieties from human isolated LDL were also protected against Cu2+-induced oxidation. The results presented herein are the first to show that (i) (PhSe)2 inhibits lipid peroxidation in human isolated LDL in vitro, (ii) this phenomenon is related to its thiol-peroxidase activity, and (iii) this chalcogen also prevents the oxidation of protein moieties of human LDL. Taken together, such data render (PhSe)2 a promising molecule for pharmacological studies with respect to the atherogenic process.http://www.sciencedirect.com/science/article/B6T12-4S21TS2-1/1/38250cf8bae4a4195ccd8905cf5c2a8

Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world

Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic. Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality. Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States. Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis. Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection

CF3-substituted diselenide modulatory effects on oxidative stress, induced by single and repeated morphine administrations, in susceptible tissues of mice

Studies reveal that oxidative stress is associated with morphine long-term treatment adverse effects. CF3-substituted diselenide (CF3) is a multitarget organoselenium compound that has antioxidant properties in different experimental models. This study aimed to investigate the CF3 effects against redox imbalance in peripheral and central tissues of mice, after single or multiple morphine doses. Swiss male mice received a single dose of morphine (5 mg/kg, s.c) and CF3 (10 mg/kg, i.g), or morphine was repeatedly injected (5 mg/kg, s.c) and CF3 (10 mg/kg, i.g) administered twice daily for 7 days. Oxidative stress was determined in the hippocampus, liver, and kidney. CF3 reversed the increase in reactive species caused by single and multiple morphine doses in the peripheral tissues. CF3 increased hepatic non-protein thiol (NPSH) levels and the superoxide dismutase (SOD) activity decreased by a single morphine dose. CF3 reversed the reduction in SOD activity in the kidney of mice repeatedly exposed to morphine. The study demonstrates that peripheral tissues were more susceptible than the hippocampus to oxidative stress induced by morphine in mice. The results show that CF3 modulated parameters of oxidative stress modified by single and multiple morphine administrations in peripheral and central tissues of mice.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

The hypolipidemic action of a diet supplemented with p,p’-methoxyl-diphenyl diselenide is not directly related to its antioxidant property

The present study investigated if a p,p’-methoxyl-diphenyl diselenide (MeOPhSe)2-supplemented diet causes toxicity in rats. A second aim of this study was to determine if a 10 ppm (MeOPhSe)2-supplemented diet has hypolipidemic effect on Triton WR-1339-induced hyperlipidemia in rats. In order to rule out the antioxidant property of (MeOPhSe)2 in its hypolipidemic action, parameters of oxidative stress were carried out. Wistar rats were fed with 3, 10 or 30 ppm of (MeOPhSe)2-supplemented diet for 30 days. None of (MeOPhSe)2-supplemented diets caused alteration in general parameters of toxicity and lipid profile of rats. The hypolipidemic effect of 10 ppm of (MeOPhSe)2-supplemented diet on rats treated with Triton WR-1339 (400 mg/kg, intraperitoneal) was investigated. The (MeOPhSe)2-supplemented diet partially protected against the levels of total cholesterol (TC) and non-HDL-C and reduced the atherogenic index (AI) increased by Triton WR-1339 in rats. A positive correlation between TC and triglyceride levels (r=0.679) and non HDL-C levels (r=0.929) and AI (r=0.889) was demonstrated. Triton WR-1339 altered parameters of oxidative stress in livers of rats but (MeOPhSe)2-supplemented diet did not protect against these alterations. The results demonstrated that the hypolipidemic action of (MeOPhSe)2-supplemented diet is not directly related to its antioxidant property and devoid of systemic toxicity in rats at the parameters analyzed.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Combined selection for grain yield, cooking quality and minerals in the common bean

Combined selection for grain yield, cooking and nutritional quality is important in the improvement of the common bean (Phaseolus vulgaris L). The objectives of this study therefore were to evaluate the genetic variability of the common bean lines as to grain yield, cooking time and the minerals concentration in the grains, to study the linear association between these characteristics and use the index to select those advanced lines which are superior in most of these characteristics. To do this, 16 common bean lines were evaluated in two growing seasons. The data were subjected to variance analysis and the Pearson correlation, and the index was then estimated. The lines presented genetic variability for grain yield, cooking time and calcium and iron concentrations in the grains. Low values for the correlation estimates were found between grain yield and concentrations of potassium (r = -0.3497), zinc (r = 0.3486) and copper (r = 0.2729). The Gen Pr 14-2-3 line presents the highest index for grain yield, cooking time and concentrations of potassium, iron, zinc and copper in the grains, being recommended for controlled hybridization in common bean breeding programs for biofortification

Evaluation of special grains bean lines for grain yield, cooking time and mineral concentrations

Genetic variability of 32 inbred special grains bean lines was investigated for grain yield, mass of 100 grains, cooking time, and mineral concentrations in grains, and Z index was used for selection of superior lines in most of the characters. IAC Centauro, IAC Galante, Xamego, Ouro Branco, Montcalm, and Hooter lines presented high yield grain, short cooking time (less than 24 min), and high potassium (>14 g kg-1dry matter &#91;DM&#93;), calcium (>1.42 g kg-1DM), iron (>97.60 mg kg-1DM), zinc (>29.05 mg kg-1DM) and copper (>8.67 mg kg-1DM) concentrations, and their dietary use is therefore recommended. Cal-96 line presents higher Z index for grain yield and for the most of the minerals, and its use is recommended for crosses for the development of superior lines