An improved expression and purification protocol enables the structural characterization of Mnt1, an antifungal target from Candida albicans.

BACKGROUND: Candida albicans is one of the most prevalent fungi causing infections in the world. Mnt1 is a mannosyltransferase that participates in both the cell wall biogenesis and biofilm growth of C. albicans. While the cell wall performs crucial functions in pathogenesis, biofilm growth is correlated with sequestration of drugs by the extracellular matrix. Therefore, antifungals targeting CaMnt1 can compromise fungal development and potentially also render Candida susceptible to drug therapy. Despite its importance, CaMnt1 has not yet been purified to high standards and its biophysical properties are lacking. RESULTS: We describe a new protocol to obtain high yield of recombinant CaMnt1 in Komagataella phaffii using methanol induction. The purified protein's identity was confirmed by MALDI-TOF/TOF mass spectroscopy. The Far-UV circular dichroism (CD) spectra demonstrate that the secondary structure of CaMnt1 is compatible with a protein formed by α-helices and ß-sheets at pH 7.0. The fluorescence spectroscopy results show that the tertiary structure of CaMnt1 is pH-dependent, with a greater intensity of fluorescence emission at pH 7.0. Using our molecular modeling protocol, we depict for the first time the ternary complex of CaMnt1 bound to its two substrates, which has enabled the identification of residues involved in substrate specificity and catalytic reaction. Our results corroborate the hypothesis that Tyr209 stabilizes the formation of an oxocarbenium ion-like intermediate during nucleophilic attack of the acceptor sugar, opposing the double displacement mechanism proposed by other reports. CONCLUSIONS: The methodology presented here can substantially improve the yield of recombinant CaMnt1 expressed in flask-grown yeasts. In addition, the structural characterization of the fungal mannosyltransferase presents novelties that can be exploited for new antifungal drug's development.

QSAR studies on benzothiophene derivatives as Plasmodium falciparum N-myristoyltransferase inhibitors: Molecular insights into affinity and selectivity.

Malaria is an infectious disease caused by protozoan parasites of the genus Plasmodium and transmitted by Anopheles spp. mosquitos. Due to the emerging resistance to currently available drugs, great efforts must be invested in discovering new molecular targets and drugs. N-myristoyltransferase (NMT) is an essential enzyme to parasites and has been validated as a chemically tractable target for the discovery of new drug candidates against malaria. In this work, 2D and 3D quantitative structure-activity relationship (QSAR) studies were conducted on a series of benzothiophene derivatives as P. falciparum NMT (PfNMT) and human NMT (HsNMT) inhibitors to shed light on the molecular requirements for inhibitor affinity and selectivity. A combination of Quantitative Structure-activity Relationship (QSAR) methods, including the hologram quantitative structure-activity relationship (HQSAR), comparative molecular field analysis (CoMFA), and comparative molecular similarity index analysis (CoMSIA) models, were used, and the impacts of the molecular alignment strategies (maximum common substructure and flexible ligand alignment) and atomic partial charge methods (Gasteiger-Hückel, MMFF94, AM1-BCC, CHELPG, and Mulliken) on the quality and reliability of the models were assessed. The best models exhibited internal consistency and could reasonably predict the inhibitory activity against both PfNMT (HQSAR: q2 /r2 /r2pred = 0.83/0.98/0.81; CoMFA: q2 /r2 /r2pred = 0.78/0.97/0.86; CoMSIA: q2 /r2 /r2pred = 0.74/0.95/0.82) and HsNMT (HQSAR: q2 /r2 /r2pred = 0.79/0.93/0.74; CoMFA: q2 /r2 /r2pred = 0.82/0.98/0.60; CoMSIA: q2 /r2 /r2pred = 0.62/0.95/0.56). The results enabled the identification of the polar interactions (electrostatic and hydrogen-bonding properties) as the major molecular features that affected the inhibitory activity and selectivity. These findings should be useful for the design of PfNMT inhibitors with high affinities and selectivities as antimalarial lead candidates.

Reporter Replicons for Antiviral Drug Discovery against Positive Single-Stranded RNA Viruses.

Single-stranded positive RNA ((+) ssRNA) viruses include several important human pathogens. Some members are responsible for large outbreaks, such as Zika virus, West Nile virus, SARS-CoV, and SARS-CoV-2, while others are endemic, causing an enormous global health burden. Since vaccines or specific treatments are not available for most viral infections, the discovery of direct-acting antivirals (DAA) is an urgent need. Still, the low-throughput nature of and biosafety concerns related to traditional antiviral assays hinders the discovery of new inhibitors. With the advances of reverse genetics, reporter replicon systems have become an alternative tool for the screening of DAAs. Herein, we review decades of the use of (+) ssRNA viruses replicon systems for the discovery of antiviral agents. We summarize different strategies used to develop those systems, as well as highlight some of the most promising inhibitors identified by the method. Despite the genetic alterations introduced, reporter replicons have been shown to be reliable systems for screening and identification of viral replication inhibitors and, therefore, an important tool for the discovery of new DAAs.

Structural and mechanistic insight from antiviral and antiparasitic enzyme drug targets for tropical infectious diseases.

With almost half of the world population living at risk, tropical infectious diseases cause millions of deaths every year in developing countries. Considering the lack of economic prospects for investment in this field, approaches aiming the rational design of compounds, such as structure-based drug discovery (SBDD), fragment screening, target-based drug discovery, and drug repurposing are of special interest. Herein, we focused in the advances on the field of SBDD targeting arboviruses such as dengue, yellow fever, zika and chikungunya enzymes of the RNA replication complex (RC) and enzymes involved in a variety of pathways essential to ensure parasitic survival in the host, for malaria, Chagas e leishmaniasis diseases. We also highlighted successful examples such as promising new inhibitors and molecules already in preclinical/clinical phase tests, major gaps in the field and perspectives for the future of drug design for tropical diseases.

Prótese valvar Starr-Edwards - meio século de durabilidade / Starr-Edwards valve prothesis - half a century of durability

A prótese de Star-Edwards foi a primeira válvula mecânica a ser implantada no mundo, no ano de 1960. Cerca de 200.000 pacientes foram beneficiados com esse modelo, porém, caiu em desuso por suas frequentes complicações como hemólise, anemia e tromboembolismos, apesar de sua notável durabilidade. Neste artigo apresentamos um caso de paciente com a maior durabilidade com manutenção da funcionalidade da prótese S-E, já relatado na literatura. O paciente fez o seguimento cardiológico corretamente, bem como usou a anticoagulação adequada. Apresentou disfunção de outras valvas, porém a prótese S-E manteve-se estável e funcional. Inclusive, necessitou de cirurgia para troca valvar mitral, mas não da prótese de S-E em posição aórtica. Este relato foi realizado através da história clínica do paciente e do levantamento de dados da literatura sobre próteses valvares e sua durabilidade. Existem relatos de durabilidade de próteses valvares com aproximadamente 30 a 40 anos, mas nenhum relato próximo ou igual a este com 49 anos de durabilidade. A importância dos cuidados pós-operatórios, uso correto dos anticoagulantes e o seguimento clínico para controle das possíveis complicações da prótese, foi mostrada neste artigo através do relato desse caso

In 1960, the Starr-Edwards prosthesis became the first mechanical valve to be implanted, worldwide. Roughly 200,000 patients benefited from this model. However, it has now fallen out of use due to its frequent complications, such as hemolysis, anemia and thromboembolisms, despite its noteworthy durability. In this article, we present a case of a patient with the longest durability with maintenance of functionality of the S-E prosthesis reported in the literature. The patient had correctly followed the cardiological follow-up, including adequate use of anti-coagulant medications. The patient presented dysfunction in other valves, but the S-E prosthesis remained stable and functional. The patient even required mitral valve replacement surgery, but not for the S-E prosthesis in the aortic position. This report was based on patient's clinical history and a survey of the literature data on valve prostheses and their durability. There are reports of prostheses remaining stable for approximately 30 to 40 years, but none that came close to this one, which had lasted for 49 years The importance of postoperative care, the correct use of anti-coagulant medicines, and clinical follow-up to minimize the possible complications of the prosthesis, were shown in this article through this case report

Antiplasmodial profile of selected compounds from Malaria Box: in vitro evaluation, speed of action and drug combination studies.

BACKGROUND: Artemisinin-based combination therapy (ACT) is used as the first-line treatment of uncomplicated malaria caused by the Plasmodium falciparum parasite and chloroquine-resistant Plasmodium vivax parasites. Evidence of resistance to ACT has been reported in Cambodia, and without new and effective anti-malarial agents, malaria burden and mortality will rise. METHODS: The used MolPrint 2D fingerprints and the Tanimoto similarity index were used to perform a structural similarity search within the Malaria Box collection to select diverse molecular scaffolds that are different from artesunate. Next, the inhibitory potency against the P. falciparum 3D7 strain (SYBR Green I inhibition assay) and the cytotoxicity against HepG2 cells (MTT and neutral red assays) were evaluated. Then, the speed of action, the combination profile of selected inhibitors with artesunate, and the P. berghei in vivo activity of the best compounds were assessed. RESULTS: A set of 11 structurally diverse compounds from the Malaria Box with a similarity threshold of less than 0.05 was selected and compared with artesunate. The in vitro inhibitory activity of each compound confirmed the reported potencies (IC50 values ranging from 0.005 to 1 µM). The cytotoxicity of each selected compound was evaluated and used to calculate the selectivity index (SI values ranging from 15.1 to 6100). Next, both the speed of action and the combination profile of each compound with artesunate was assessed. Acridine, thiazolopyrimidine, quinoxaline, benzimidazole, thiophene, benzodiazepine, isoxazole and pyrimidoindole derivatives showed fast in vitro inhibitory activity of parasite growth, whereas hydrazinobenzimidazole, indenopyridazinone and naphthalenone derivatives were slow-acting in vitro inhibitors. Combinatory profile evaluation indicated that thiazolopyrimidinone and benzodiazepine derivatives have an additive profile, suggesting that the combination of these inhibitors with artesunate is favourable for in vitro inhibitory activity. The remaining compounds showed an antagonistic combinatory profile with artesunate. The collected data indicated that the indenopyridazinone derivative, a bc1 complex inhibitor, had a similar association profile in combination with proguanil when compared to atovaquone combined with proguanil, thereby corroborating the correlation between the molecular target and the combination profile. Lastly, the in vivo activity of the thiazolopyrimidinone and benzodiazepine derivatives were assessed. Both compounds showed oral efficacy at 50 mg/kg in a mouse model of Plasmodium berghei malaria (64% and 40% reduction in parasitaemia on day 5 post-infection, respectively). CONCLUSIONS: The findings in this paper shed light on the relationship among the speed of action, molecular target and combinatory profile and identified new hits with in vivo activity as candidates for anti-malarial combination therapy.

Prevalência de obesidade e nível de informação sobre ações de prevenção e promoção à saúde no interior paulista / Prevalence of obesity and level of information on prevention of shares and promoting health in the interior

Objetivos: Identificar a prevalência de obesidade e sua associação com Hipertensão Arterial Sistêmica (HAS) e o nível de informação sobre ações de prevenção e promoção de saúde relacionada à HAS e obesidade. Métodos: Estudo transversal, com participantes da campanha de saúde "Eu sou 12 por 8". A obesidade foi avaliada pelo Índice de Massa Corporal (IMC) e pela Circunferência Abdominal (CA). A Pressão Arterial (PA) foi aferida por método indireto e considerada HAS aquela com PA sistólica ≥ 140mmHg. Foi aplicado um questionário para avaliar os dados sociodemográficos, HAS referida e nível de informação de ações de prevenção e promoção de saúde. Os dados foram analisados com estatística descritiva e a associação de dados por meio de teste G e teste qui-quadrado com nível de significância de 5%. Resultados: Houve associação estatística entre indivíduos com HAS referida e aumento do IMC e CA (p<0,0001) e também com indivíduos com HAS não referida, que apresentaram PAS ≥ 140 mmHg e aumento da CA (p<0,0023). Deste total, 84,3% receberam informações quanto às complicações da HAS, sendo que 42,3% por meio da Estratégia Saúde da Família (ESF). Sobre a obesidade, 55,3% foram informados, e o principal meio foi a mídia com 26,5%. Houve significância estatística na associação entre a HAS referida e informação sobre as complicações da HAS (p<0,0111). Conclusão: A aferição da CA pode contribuir consideravelmente como fator de risco para a HAS. Melhor análise deve ser feita sobre qual o momento em que as informações sobre as complicações da HAS são oferecidas.

Objectives: To identify the prevalence of obesity and its association with systemic arterial hypertension (SAH) and the level of information on prevention and health promotion related to hypertension and obesity. Methods: Cross-sectional study, with participants from health campaign "I'm 12 by 8". Obesity was measured by Body Mass Index (BMI) and Waist Circumference (CA). Blood pressure (BP) was measured by indirect method and was considered hypertension when systolic blood pressure ≥ 140 mmHg. A questionnaire was used to evaluate the socio-demographic data, said SAH and level of information of preventive actions and health promotion. Data were analyzed with descriptive statistics and data binding through G test and chi-square test with 5% significance level. Results: There was statistical association among individuals with hypertension and increased BMI and WC (p <0.0001) and with individuals with hypertension not mentioned, which showed SBP ≥ 140 mmHg and increased CA (p <0.0023). Of this total, 84.3% received information on the complications of hypertension, through the Family Health Strategy (FHS) with 42.3%. About obesity, 55.3% were informed and the main communication method was the media with 26.5%. There was statistically significant association between SAH and said information about the complications of hypertension (p <0.0111). Conclusion: The measurement of CA can contribute significantly as a risk factor for hypertension. Better analysis should be done on at what time the information about the complications of hypertension are offered.

A importância das sociedades de cardiologia nas ações preventivas em relação a obesidade e hipertensão arterial em uma cidade do Oeste Paulista / The role of Brazilian cardiology societies in the promotion of preventive measures related to obesity and arterial hypertension in a western city of São Paulo state

Introdução: Condições como hipertensão arterial (HAS) e obesidade são atualmente as mais prevalentes na população, devendo ser abordados por políticas públicas eficientes. Intervenções a nível coletivo têm se mostrado mais efetivas; para isso, estratégias de comunicação de massa, atividades interativas e propostas que visem mudanças no estilo de vida devem ser elaboradas. O engajamento de entidades como as Sociedades de Cardiologia garante maior referencial técnico. Objetivo: Identificar as ações preventivas promovidas na Campanha "Eu sou 12 por 8" em relação à obesidade e HAS em uma cidade do interior paulista. Métodos: Estudo transversal com participantes da campanha "Eu sou 12 por 8" promovida pela Sociedade Brasileira de Cardiologia. Foram analisadas a Pressão Arterial (PA), Índice de Massa Corpórea (IMC), Circunferência Abdominal (CA) e aplicação de um questionário sobre as ações de prevenção e promoção à saúde. Resultados: Foi constatada maior prevalência de HAS à medida que se aumenta o IMC e essa tendência se repetiu para medida da CA (p<0,0001), evidenciando a íntima relação entre IMC e CA com o diagnóstico de HAS. Em relação às ações de promoção e prevenção 85% receberam informações sobre a nocividade da HAS, sendo a mídia o principal meio disseminador. Além disso, cerca de 50% dos usuários não conhecem os malefícios da obesidade. Também foi observado maior conhecimento sobre os danos da HAS em pacientes previamente diagnosticados. Conclusão: Pela elevada prevalência de obesidade e HAS e sua relação intercausal, é imprescindível a realização de atividades de prevenção. A identificação do papel da mídia nestas ações demonstra como melhor atingir a população. Por fim, percebe-se a Sociedade de Cardiologia como agente necessário, de forma a realizar ações benéficas à saúde.

Introdution: Clinical conditions such as arterial hypertension and obesity are the most prevalent cardiovascular risk-factors in the population; which means that both must be addressed by well-planned, efficient public policies. Since interventions in a collective level have been well-received by patients, it is necessary to resort strategies of mass communication, interactive activities and lifestyle alterations to improve health promotion programs. The participation of entities such as the Brazilian Cardiology Societies guarantees major technical reference. Objective: To identify the preventive measure promoted during the "Eu sou 12 por 8" campaign related to obesity and hypertension in a city of São Paulo state. Methodology: A transversal study with participants of Eu sou 12 por 8" campaign. The variables of interest were blood pressure (BP), body mass index (BMI) and abdominal circumference (AC), the evaluation of preventive actions regarding cardiovascular disease occurred through a self-elaborated questionnaire. Results: The results showed positive correlations between hypertension and the BMI; as well as hypertension and AC: as the BMI and CI grow, the greater is the prevalence for hypertension (p<0,0001), pointing the intimate relation that both the BMI and AC hold with the diagnosis of hypertension. Regarding the promotion and prevention actions, 85% of the participants had received information about the dangers and implications of hypertension ­ having the media as its main source. In addition, almost half of the users declared not to acknowledge obesities' future consequences. It has also been observed a major understanding of the hypertensive disease in patients that had been previously diagnosed. Conclusion: The realization of activities in order to promote cardiovascular health is extremely necessary, due to the elevated prevalence of obesity and hypertension. Also, to identify the medias' role in such campaigns demonstrates a more efficient way to reach individuals. Finally, the role of the Brazilian Cardiology Society is to act in the community, developing actions to enrich local health structure.

Accelerated corneal collagen crosslinking: Technique, efficacy, safety, and applications.

Corneal collagen crosslinking (CXL) is an approach used to increase the biomechanical stability of the stromal tissue. Over the past 10 years, it has been used to halt the progression of ectatic diseases. According to the photochemical law of reciprocity, the same photochemical effect is achieved with reduced illumination time and correspondingly increased irradiation intensity. Several new CXL devices offer high ultraviolet-A irradiation intensity with different time settings. The main purpose of this review was to discuss the current use of different protocols of accelerated CXL and compare the efficacy and safety of accelerated CXL with the efficacy and safety of the established conventional method. Accelerated CXL proved to be safe and effective in halting progression of corneal ectasia. Corneal shape responses varied considerably, as did the demarcation line at different irradiance settings; the shorter the exposure time, the more superficial the demarcation line. FINANCIAL DISCLOSURE: Dr. Santhiago is a consultant to Ziemer Ophthalmic Systems AG and Alcon Laboratories, Inc. None of the authors has a financial or proprietary interest in any material or method mentioned.

Modulation of MAPK and NF-954;B Signaling Pathways by Antioxidant Therapy in Skeletal Muscle of Heart Failure Rats.

BACKGROUND/AIMS: Although increased oxidative stress plays a role in heart failure (HF)-induced skeletal myopathy, signaling pathways involved in muscle changes and the role of antioxidant agents have been poorly addressed. We evaluated the effects of N-acetylcysteine (NAC) on intracellular signaling pathways potentially modulated by oxidative stress in soleus muscle from HF rats. METHODS AND RESULTS: Four months after surgery, rats were assigned to Sham, myocardial infarction (MI)-C (without treatment), and MI-NAC (treated with N-acetylcysteine) groups. Two months later, echocardiogram showed left ventricular dysfunction in MI-C; NAC attenuated diastolic dysfunction. Oxidative stress was evaluated in serum and soleus muscle; malondialdehyde was higher in MI-C than Sham and did not differ between MI-C and MI-NAC. Oxidized glutathione concentration in soleus muscle was similar in Sham and MI-C, and lower in MI-NAC than MI-C (Sham 0.168 ± 0.056; MI-C 0.223 ± 0.073; MI-NAC 0.136 ± 0.023 nmol/mg tissue; p = 0.014). Western blot showed increased p-JNK and decreased p38, ERK1/2, and p-ERK1/2 in infarcted rats. NAC restored ERK1/2. NF-954;B p65 subunit was reduced; p-Ser276 in p65 and I954;B was increased; and p-Ser536 unchanged in MI-C compared to Sham. NAC did not modify NF-954;B p65 subunit, but decreased p-Ser276 and p-Ser536. CONCLUSION: N-acetylcysteine modulates MAPK and NF-954;B signaling pathways in soleus muscle of HF rats.

Antibodies Against Glycolipids Enhance Antifungal Activity of Macrophages and Reduce Fungal Burden After Infection with Paracoccidioides brasiliensis.

Paracoccidioidomycosis is a fungal disease endemic in Latin America. Polyclonal antibodies to acidic glycosphingolipids (GSLs) from Paracoccidioides brasiliensis opsonized yeast forms in vitro increasing phagocytosis and reduced the fungal burden of infected animals. Antibodies to GSL were active in both prophylactic and therapeutic protocols using a murine intratracheal infection model. Pathological examination of the lungs of animals treated with antibodies to GSL showed well-organized granulomas and minimally damaged parenchyma compared to the untreated control. Murine peritoneal macrophages activated by IFN-γ and incubated with antibodies against acidic GSLs more effectively phagocytosed and killed P. brasiliensis yeast cells as well as produced more nitric oxide compared to controls. The present work discloses a novel target of protective antibodies against P. brasiliensis adding to other well-studied mediators of the immune response to this fungus.

Effect of whitening toothpaste on superficial roughness of composite resin.

This study sought to evaluate the effect of different toothpastes with whitening action on the average surface roughness (Ra) of a microhybrid composite resin. Twenty-five specimens of composite resin were prepared and distributed randomly among 5 experimental groups (n = 5). Groups 1-3 were treated with whitening toothpastes: Close-up Extra Whitening, Colgate Ultra White, and Colgate Total 12 Whitening. Group 4 was a negative control group (with samples brushed with deionized water), and Group 5 was a positive control group (with samples brushed using a non-whitening toothpaste). A profilometer was used to determine Ra before and after brushing. A simulated brushing machine was used for all groups, providing horizontal back and forth movement with an amplitude of 3.8 cm applying an axial load of 200 g and a speed of 356 rpm, totaling 20,000 cycles. To determine the Ra in each specimen, 6 readings were taken at various positions before and after brushing. The results were submitted to variance analyses and Tukey's test. (P < 0.05). Groups 1, 2, 3, and 5 demonstrated statistically significant differences between initial and final averages. Based on these results, it was determined that brushing with toothpaste, regardless of formulation, significantly increased the Ra of the resin composite evaluated in this study.

Análise da intensidade de fluorescência em diferentes compósitos após exposição a agentes clareadores caseiros à base de peróxido de carbamida em diferentes concentrações / Analysis of fluorescence intensity in different composites after exposure to different concentrations of carbamide peroxide home bleaching agents

Objetivo: o objetivo neste estudo foi avaliar a influência de agentes clareadores à base de peróxido de carbamida (PC), em diferentes concentrações, sobre a fluorescência de três compósitos. Métodos: foram confeccionados 27 corpos de prova divididos em 9 grupos (n = 3), que foram armazenados em água deionizada, expostos ao PC 10% por 6 horas diárias e PC 22% por 1 hora diária, durante 14 dias. Após, foi realizada a leitura da fluorescência em um espectrofotômetro. Os valores de intensidade de fluorescência obtidos foram submetidos aos testes Shapiro-Wilk, Levene e Games-Howell (p < 0,05). Resultados: a média dos valores de intensidade de fluorescência para os grupos controle dos compósitos Esthet-X e Opallis não apresentou diferença estatisticamente significativa. Entretanto, o compósito Charisma apresentou intensidade de fluorescência estatisticamente diferente da dos demais. Após serem expostas aos diferentes agentes clareadores, apenas o compósito Charisma exposto ao PC 22% apresentou alterações estatisticamente significativas, aumentando a fluorescência. Conclusão: a intensidade de fluorescência pode ser afetada pela ação de agentes clareadores à base de PC, dependendo de sua concentração e das características do compósito.

Intensidade de fluorescência em resina composta: influência do polimento superficial e dos meios de armazenagem / Fluorescence intensity in composite resin: influence of superficial polishing and storage means

Introdução: A resina composta é um material versátil em Odontologia Estética, principalmente por suas propriedades ópticas, dentre as quais a fluorescência. Poucos são os estudos que avaliaram esta propriedade e a comparação dos resultados encontrados torna-se difícil em função da inexistência de padronização nas metodologias na confecção e na armazenagem dos corpos de prova. Objetivo: Verificar a influência do polimento superficial e do meio de armazenagem, em estudos in vitro, em que se avalia a propriedade óptica de fluorescência em resinas compostas. Material e Método: Foram preparados 70 corpos de prova circulares (10 mm × 2 mm ) com resina composta microhíbrida (Opallis,- A2E - FGM.) Os meios de armazenagem foram: água deionizada, água da torneira e saliva artificial. Os protocolos de polimento superficial, realizados em politriz após a obtenção dos corpos de prova, utilizaram lixas de granulações 600, 1200 e 2500. Os valores de intensidade de fluorescência foram avaliados através do espectrofotômetro Cary Eclipse, após 1, 7 e 21 dias. Resultado: Não houve diferença estatisticamente significativa na Intensidade de Fluorescência entre os grupos submetidos aos diferentes protocolos de polimento. Quanto aos meios de armazenagem, a partir do sétimo dia, a variação de fluorescência foi significativamente maior em água da torneira e deionizada, quando comparada à variação observada em saliva artificial, resultado que se manteve após 21 dias. Conclusão: O protocolo de polimento superficial não promoveu alterações significativas na fluorescência da resina composta avaliada. Quanto ao meio de armazenagem, a intensidade de fluorescência foi menos afetada quando em saliva artificial.

Introduction: Resin composite is a versatile material in cosmetic dentistry due mainly to its optical properties, fluorescence among them. There are a few studies which assessed such property and a comparison of results becomes difficult due to the lack of a pattern in the specimens storage and confection methodologies. Objective: Verify the influence of superficial polishing and means of storage in in vitro studies that assess the optical property of fluorescence in dental resin composites. Material and Method: 70 circular specimens (10 mm × 2 mm) were prepared with microhybrid composite resin (Opallis, - A2E - FGM). The means of storage were: deionized water, tap water and artificial saliva. The superficial polishing protocols used 600, 1200 and 2500 sandpaper grit sizes, accomplished with polisher after specimens were obtained. The fluorescence intensity values were assessed using Cary Eclipse Fluorescence Spectrophotometer after 1, 7 and 21 days. Result: There was not a statistically significant difference in Fluorescence Intensity among the groups submitted to the different polishing protocols. Concerning the means of storage, from the seventh day on the fluorescence variation was significantly bigger in tap and deionized water, compared to artificial saliva, such result kept on after 21 days. Conclusion: the superficial polishing protocol did not promote significant changes in the assessed resin composite fluorescence. Regarding the means of storage, the fluorescence intensity was less affected when in artificial saliva.

Discovery of new potential hits of Plasmodium falciparum enoyl-ACP reductase through ligand- and structure-based drug design approaches.

We here report the discovery of novel Plasmodium falciparum enoyl-ACP reductase (PfENR) inhibitors as new antimalarial hits through ligand- and structure-based drug design approaches. We performed 2D and 3D QSAR studies on a set of rhodanine analogues using hologram QSAR (HQSAR), comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) techniques. Statistical and satisfactory results were obtained for the best HQSAR (r(2) of 0.968 and qLOO(2) of 0.751), CoMFA (r(2) of 0.955 and qLOO(2) of 0.806) and CoMSIA (r(2) of 0.965 and qLOO(2) of 0.659) models. The information gathered from the QSAR models guided us to design new PfENR inhibitors. Three new hits were predicted with potency in the submicromolar range and presented drug-like properties.

Assessment of the release of mercury from silver amalgam alloys exposed to different 10% carbamide peroxide bleaching agents.

This in vitro study assessed the amount of mercury (Hg) released from a silver amalgam alloy following the application of different 10% carbamide peroxide bleaching agents. A total of 30 specimens (2 mm thick x 4 mm in diameter) were stored in deionized water at 37°C for 7 days. Next, the control group (n = 10) remained in the deionized water for 15 days, while the remaining samples were exposed to 1 of 2 bleaching agents (n = 10) for 8 hours daily (total exposure = 120 hours); for the remaining 16 hours, specimens in the test groups were stored in deionized water at 37°C under relative humidity. After this period, the quantity of Hg in the deionized water was assessed (using atomic absorption spectrophotometry) and compared to the amount of Hg at baseline. The results indicate that exposing amalgam alloys to bleaching agents released greater amounts of Hg compared to exposing samples to deionized [corrected] water.

Structural and chemical basis for enhanced affinity to a series of mycobacterial thymidine monophosphate kinase inhibitors: fragment-based QSAR and QM/MM docking studies.

Tuberculosis (TB) still remains one of the most deadly infectious diseases. Mycobacterium tuberculosis thymidine monophosphate kinase (TMPKmt) has emerged as an attractive molecular target for the design of a novel class of anti-TB agents since blocking it will affect the pathways involved in DNA replication. Aiming at shedding some light on structural and chemical features that are important for the affinity of thymidine derivatives to TMPKmt, we have employed a special fragment-based method to develop robust quantitative structure-activity relationship models for a large and chemically diverse series of thymidine-based analogues. Significant statistical parameters (r2= 0.94, q2= 0.76, r2pred= 0.89) were obtained, indicating the reliability of the hologram QSAR model in predicting the biological activity of untested compounds. The 2D model was then used to predict the potency of an external test set, and the predicted values obtained from the HQSAR model were in good agreement with the experimental results. We have accordingly designed novel TMPKmt inhibitors by utilizing the fragments proposed by HQSAR analysis and predicted with good activity in the developed models. The new designed compounds also presented drug-like characteristics based on Lipinski's rule of 5. The generated molecular recognition patterns gathered from the HQSAR analysis combined with quantum mechanics/molecular mechanics (QM/MM) docking studies, provided important insights into the chemical and structural basis involved in the molecular recognition process of this series of thymidine analogues and should be useful for the design of new potent anti-TB agents.

Ion release from a composite resin after exposure to different 10% carbamide peroxide bleaching agents.

OBJECTIVE: This in vitro study evaluated the influence of two 10% carbamide peroxide bleaching agents - a commercial product (Opalescence PF; Ultradent Products, Inc.) and a bleaching agent prepared in a compounding pharmacy - on the chemical degradation of a light-activated composite resin by determining its release of ions before and after exposure to the agents. MATERIAL AND METHODS: Thirty composite resin (Filtek Z250; 3M/ESPE) samples were divided into three groups: group I (exposed to Opalescence PF commercial bleaching agent), group II (exposed to a compounded bleaching agent) and group III (control - Milli-Q water). After 14 days of exposure, with a protocol of 8 h of daily exposure to the bleaching agents and 16 h of immersion in Milli-Q water, the analysis of ion release was carried out using a HP 8453 spectrophotometer. The values were analyzed statistically by ANOVA, Tukey's test and the paired t-tests. The significance level was set at 5%. RESULTS: After 14 days of the experiment, statistically significant difference was found between group II and groups I and III, with greater ion release from the composite resin in group II. CONCLUSIONS: The compounded bleaching agent had a more aggressive effect on the composite resin after 14 days of exposure than the commercial product and the control (no bleaching).

Ion release from a composite resin after exposure to different 10% carbamide peroxide bleaching agents

OBJECTIVE: This in vitro study evaluated the influence of two 10% carbamide peroxide bleaching agents - a commercial product (Opalescence PF; Ultradent Products, Inc.) and a bleaching agent prepared in a compounding pharmacy - on the chemical degradation of a light-activated composite resin by determining its release of ions before and after exposure to the agents. MATERIAL AND METHODS: Thirty composite resin (Filtek Z250; 3M/ESPE) samples were divided into three groups: group I (exposed to Opalescence PF commercial bleaching agent), group II (exposed to a compounded bleaching agent) and group III (control - Milli-Q water). After 14 days of exposure, with a protocol of 8 h of daily exposure to the bleaching agents and 16 h of immersion in Milli-Q water, the analysis of ion release was carried out using a HP 8453 spectrophotometer. The values were analyzed statistically by ANOVA, Tukey's test and the paired t-tests. The significance level was set at 5%. RESULTS: After 14 days of the experiment, statistically significant difference was found between group II and groups I and III, with greater ion release from the composite resin in group II. CONCLUSIONS: The compounded bleaching agent had a more aggressive effect on the composite resin after 14 days of exposure than the commercial product and the control (no bleaching).

Residual oxygen releasing time from dental structure after carbamide peroxide exposure: study of the effects of a neutralizer gel.

The purpose of this article was to assess in vitro the effects of a catalase-based neutralizer gel in the release of residual oxygen in permanent human teeth specimens exposed to 10% carbamide peroxide. Thirty teeth specimens (5.0 x 5.0 x 3.0 mm3) were randomly divided into three groups (n = 10): Group 1, nonbleached negative control specimens; Group 2, bleached positive control specimens; and Group 3, bleached specimens exposed to a catalase-based gel. The bleaching treatment was performed six hours per day for 14 days. At the end of the bleaching treatment, Group 3 specimens were immersed in a receptacle containing the catalase-based experimental gel for three minutes. Titrations were performed to determine the quantity of residual oxygen that each test specimen released, starting immediately after the end of the bleaching treatment and exposure (or not) to the catalase-based gel, and repeated on days 1-5, 10, and 15. The values obtained were statistically analyzed by ANOVA and a Tukey post hoc test (P < 0.05). The release values of residual O2 for Group 2 were equal to those of Group 1 after 10 days and to those of Group 3 after five days. The use of a catalase-based experimental neutralizer gel, applied for three minutes, reduced by half the time required for complete release of residual oxygen from tooth structure after exposure to a 10% carbamide peroxide bleaching agent.