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This study investigated the effect of 7-chloro-4-(phenylselanyl) quinoline (4-PSQ) to restore the cognitive impairment caused by aging in male Wistar rats. Moreover, modulation of neuroplasticity markers, acetylcholinesterase (AChE) activity, and cholesterol levels was performed. Aged rats were intragastrically treated with 4-PSQ (5 mg/kg) for 7 days. Animals were tested in behavioral tasks, and then plasma (to determine cholesterol levels), hippocampus, and cerebral cortex (to determine neural cell adhesion molecule (NCAM) and polysialyltransferase (PST) levels, and AChE activity) were removed. Our findings demonstrated that treatment of aged rats with 4-PSQ restored short-term and long-term memories in the object recognition tests. 4-PSQ treatment did not restore exploratory activity (rearings) but partially restored locomotor activity (crossings) reduced by aging in the open-field test. Moreover, the compound restored the reduction in the NCAM and PST levels, and AChE activity in cerebral structures, as well as the increase in the plasma cholesterol levels, caused by aging in rats. In conclusion, 4-PSQ restored cognitive impairment caused by aging in rats by modulating synaptic plasticity, cholinergic system, and cholesterol levels.

CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior Resumo - O tecido ósseo é fundamental na locomoção, proteção dos órgãos internos e na produção de células do sistema hematopoiético e imunológico dos animais. As lesões neste tecido, principalmente nos animais de companhia, normalmente ocorrem devido a traumas. As fraturas têm sido bastante discutidas na ortopedia veterinária, principalmente quanto aos métodos de tratamento, tempo de recuperação e complicações. Uma opção no tratamento das lesões ósseas são os enxertos. Com o objetivo de se estudar a influência do enxerto omental livre autógeno na reparação de falha óssea utilizou-se 32 coelhos adultos, machos, não castrados da raça Nova Zelândia, com idade entre 6 e 7 meses, divididos em dois grupos (GI controle e GII tratados com enxerto omental) com 16 animais cada. Falhas ósseas segmentares de 1cm foram criadas cirurgicamente no terço médio da diáfise radio direito. No mesmo momento cirúrgico realizou-se também a celiotomia para obtenção do enxerto a partir do omento, inclusive nos animais do GI. Os animais do GII tiveram as falhas ósseas cobertas com o enxerto omental livre autógeno. Imediatamente após as cirurgias, aos 45 e 90 dias, os animais tiveram os respectivos antebraços radiografados para posterior avaliação do processo de regeneração óssea. Também foi realizada coleta de sangue para a dosagem da fosfatase alcalina óssea nos dias 0 (antes das cirurgias), 45 e 90 (após as cirurgias). Metade dos animais de cada grupo foram eutanásiados aos 45dias e aos 90 dias respectivamente para realização da coleta de amostra da área anteriormente lesionada visando a confecção de laminas histológicas. Não houve diferença nos níveis séricos da FAO entre GI e GII aos 45 e nem aos 90 dias (p=0,42), nem na avaliação radiográfica comparando os grupos (p=0,99). Histologicamente também não foi notada diferença no processo de regeneração óssea entre GI e GII, exceto pela presença de resíduos do enxerto omental em absorção, sugerindo uma reação tipo corpo estranho. O enxerto omental autógeno livre, no tratamento de falhas ósseas com 1cm de extensão no osso Rádio de coelhos Nova Zelândia, não influenciou o processo de regeneração óssea. Abstract - Bone tissue is essential in locomotion, internal organs protection and in the hematopoietic and immunological systems cells production of animals. Lesions in this tissue, especially in pet animals, usually occur due to trauma. Fractures have been widely discussed in veterinary orthopedics, mainly regarding treatment methods, recovery time and complications. An option in the treatment of bone lesions are the grafts. with aim to study the influence of the autogenous free omental graft on the repair of bone defect, 32 male, uncastrated New Zealand rabbits aged between 6 and 7 months were divided into two groups (GI control and GII treated with free omental graft) with 16 animals each. 1 cm Segmental bone defects were surgically criated in the middle third of the right Radio. At the same surgical procedure, the celiotomy was also performed to obtain the graft from the omentum, including the GI animals. The GII animals had bony defects covered with autogenous free omental graft. Immediately after the surgeries and at 45 and 90 days, the animals had their respective forearms radiographed for later images evaluation. Blood samples were also collected for the measurement of bone alkaline phosphatase on days 0 (before surgery), 45 and 90 (after surgery). Half of the animals in each group were euthanized at 45 days and 90 days, respectively, to collect samples from the previously injured area, aiming the preparation of histological laminae. There was no difference in bone alkaline phosphatase serum levels between GI and GII at 45 and 90 days (p = 0.42), nor at the radiographic evaluation comparing the groups (p = 0.99). Histologically, no difference was also observed in the regeneration process of bone defects between GI and GII, except for the presence of residues from the omental graft under absorption, suggesting a foreign body reaction. The autogenous free omental graft, on treatment of 1 cm extension bone defects in New Zealand rabbit Radio, did not influence the bone regeneration process. Dissertação (Mestrado)

Physical methods such as electroporation have been used to improve the DNA uptake efficiency of sperm cells. This study aims to develop an efficient capillary-type electroporation method for incorporation of exogenous DNA into bovine cryopreserved sperm cells with minimal detrimental effects for later use in SMGT. Electroporation of the samples was performed in 2 different groups (with 1 μg of DNA and without DNA transfection) and under five different voltages: 500 V, 600 V, 700 V, 800 V and 900 V. Non-electroporated sperm cells (with and without DNA) were used as control. Kinetics parameters were determined using computer assisted semen analyses, whereas membrane integrity, fluidity, mitochondrial function and DNA uptake were evaluated by flow cytometry. Results revealed that all tested voltages reduced electroporated sperm motility (P 0.05) when compared to the control (non-electroporated cells). Mitochondrial function results showed no statistical difference among groups. Similarly, groups electroporated with lower (500 V, 600 V and 700 V) voltages showed no difference in cell membrane integrity and fluidity. Groups electroporated at higher voltages (800 V and 900 V) demonstrated negative effects in cells membrane integrity when compared to other groups and control. Also, all electroporated groups demonstrated significant higher percentages of transfected sperm cells when compared to the control group (P 0.05). Under the recommendation of using voltages up to 600 V, this method represents a safe and efficient alternative for electroporation of bovine spermatozoa.

Some mammalian reference genes, which are widely used to normalize the qRT-PCR, could not be used for this purpose due to its high expression variation. The normalization with false reference genes leads to misinterpretation of results. The silversides (Odontesthes spp.) has been used as models for evolutionary, osmoregulatory and environmental pollution studies but, up to now, there are no studies about reference genes in any Odontesthes species. Furthermore, many studies on silversides have used reference genes without previous validations. Thus, present study aimed to was to clone and sequence potential reference genes, thereby identifying the best ones in Odontesthes humensis considering different tissues, ages and conditions. For this purpose, animals belonging to three ages (adults, juveniles, and immature) were exposed to control, Roundup®, and seawater treatments for 24 h. Blood samples were subjected to flow-cytometry and other collected tissues to RNA extraction; cDNA synthesis; molecular cloning; DNA sequencing; and qRT-PCR. The candidate genes tested included 18s, actb, ef1a, eif3g, gapdh, h3a, atp1a, and tuba. Gene expression results were analyzed using five algorithms that ranked the candidate genes. The flow-cytometry data showed that the environmental challenges could trigger a systemic response in the treated fish. Even during this systemic physiological disorder, the consensus analysis of gene expression revealed h3a to be the most stable gene expression when only the treatments were considered. On the other hand, tuba was the least stable gene in the control and gapdh was the least stable in both Roundup® and seawater groups. In conclusion, the consensus analyses of different tissues, ages, and treatments groups revealed that h3a is the most stable gene whereas gapdh and tuba are the least stable genes, even being considered two constitutive genes.

In this work, we present the synthesis, characterization, and computational study of the supramolecular arrangement of a new cinnamic acid derivative: ethyl-(2E)-3-(4-hydroxy-3,5-dimethoxyphenyl)-prop-2-enoate (EHD). Single crystals of EHD were obtained using ethyl ether as solvent and a slow evaporation technique. Its crystallographic structure, derived from X-ray diffraction experiments, includes a disordered water molecule on the EHD supramolecular structure. This water molecule participates in four O-H···O hydrogen bonds, which are arranged as a centrosymmetric H-bond array with the water at the center. Electronic and structural properties of the isolated EHD molecule and of the EHD molecule in the presence of one water molecule were calculated at the B3LYP/6-311++G(2d,2p) level of theory. These calculations show that the HOMO-LUMO energy gap of EHD decreases upon the introduction of the water molecule, suggesting that EHD becomes a stronger electron acceptor. These results indicate that the water molecule helps to stabilize the crystal structure in this system containing unequal numbers of acceptor and donor atoms. The supramolecular synthon involving the disordered water molecule and the supramolecular features presented here provide new possibilities in the design of functional materials and should also help us to gain a deeper understanding of the processes by which molecules recognize biological targets.

A sustentabilidade está no rol de paradigmas capazes de dar resposta à crise socioambiental que surge no decorrer das últimas décadas. As dimensões social e econômica se inserem no arcabouço do desenvolvimento e se relacionam estreitamente com a sustentabilidade na concepção contemporânea. O objetivo deste artigo é discutir a experiência de identificação de indicadores que expressem a percepção da sustentabilidade na perspectiva dos atores da Rede de Comércio Justo e Solidário Bem Terra através da análise de uma ferramenta interna de acreditação agroecológica. Para a realização deste trabalhoutilizou-se como metodologia pesquisa bibliográfica, seguida de pesquisa documental, em concomitância com a observação participante. A ferramenta de acreditação apresenta grande potencial de contribuir com a transformação social, econômica e ambiental, servindo de estímulo para as experiências de transição agroecológica ora em curso na Rede Bem da Terra, assim como para a construção de indicadores de sustentabilidade, que poderão contribuir para um modelo de desenvolvimento mais sustentável.

A new terpenoid-like bischalcone (1E,4E)-1-(4-nitrophenyl)-5-(2,6,6-trimethylcyclohex-1-enyl)-penta-1,4-dien-3-one was synthesized from a β-ionone and 4-nitrobenzaldehyde by Claisen-Schmidt condensation reaction and its structure was determined by single crystal X-ray diffraction analysis. Additionally, this compound was featured by powder X-ray diffraction, 1H, 13C NMR and IR spectroscopy techniques. The molecule in the asymmetric unit showed disordered occupancy sites over two positions for the trimethylcyclohexene atoms. These two conformations were related by a rotation of about 180° around the axis of the C-C bond linking the six-membered ring and the olefin carbons. Single-molecule calculations using the DFT method have strengthened this structural finding, since our theoretical approaches also suggest two well-defined conformations of similar energies which resemble the molecular geometries determined by X-ray diffraction. Furthermore, the inspection of the crystal packing revealed that the hydrogen bonding patterns are different for each conformation of the compound reported here.

In this work, a promising approach to increase the advantageous properties of melatonin through its encapsulation into lipid-core nanocapsules (LNC) was examined. Oocytes were treated during in vitro maturation with non-encapsulated melatonin (Mel), melatonin-loaded lipid-core nanocapsules (Mel-LNC), and unloaded LNC. Cytotoxicity, meiotic maturation rate, development to the blastocyst stage, reactive oxygen species (ROS) and glutathione levels, mean cell number and apoptotic cell/blastocyst, and mRNA quantification were evaluated. Both Mel and Mel-LNC enhanced in vitro embryo production, however, Mel-LNC proved to be more effective at decreasing ROS levels and the apoptotic cell number/blastocyst, increasing the cleavage and blastocyst rates, up-regulating the GPX1 and SOD2 genes, and down-regulating the CASP3 and BAX genes. Mel-LNC could penetrate into oocytes and remain inside the cells until they reach the blastocyst stage. In conclusion, when melatonin was encapsulated in LNC and applied during in vitro oocyte maturation, some quality aspects of the blastocysts were improved.

Melatonin has been used as a supplement in culture medium to improve the efficiency of in vitro produced mammalian embryos. Through its ability to scavenge toxic oxygen derivatives and regulate cellular mRNA levels for antioxidant enzymes, this molecule has been shown to play a protective role against damage by free radicals, to which in vitro cultured embryos are exposed during early development. In vivo and in vitro studies have been performed showing that the use of nanocapsules as active substances carriers increases stability, bioavailability and biodistribution of drugs, such as melatonin, to the cells and tissues, improving their antioxidant properties. These properties can be modulated through the manipulation of formula composition, especially in relation to the supramolecular structures of the nanocapsule core and the surface area that greatly influences drug release mechanisms in biological environments. This study aimed to evaluate the effects of two types of melatonin-loaded nanocapsules with distinct supramolecular structures, polymeric (NC) and lipid-core (LNC) nanocapsules, on in vitro cultured bovine embryos. Embryonic development, apoptosis, reactive oxygen species (ROS) production, and mRNA levels of genes involved in cell apoptosis, ROS and cell pluripotency were evaluated after supplementation of culture medium with non-encapsulated melatonin (Mel), melatonin-loaded polymeric nanocapsules (Mel-NC) and melatonin-loaded lipid-core nanocapsules (Mel-LNC) at 10−6, 10−9, and 10−12 M drug concentrations. The highest hatching rate was observed in embryos treated with 10−9 M Mel-LNC. When compared to Mel and Mel-NC treatments at the same concentration (10−9 M), Mel-LNC increased embryo cell number, decreased cell apoptosis and ROS levels, down-regulated mRNA levels of BAX, CASP3, and SHC1 genes, and up-regulated mRNA levels of CAT and SOD2 genes. These findings indicate that nanoencapsulation with LNC increases the protective effects of melatonin against oxidative stress and cell apoptosis during in vitro embryo culture in bovine species.

Com o intuito de se conhecer a estrutura molecular e cristalina dos compostos químicos para posteriores análises físico-químicas e estudos de aplicação, lança-se mão da cristalografia como metodologia científica, que permite conhecer a estrutura de qualquer composto químico cristalino sem nenhuma informação a priori. Esta metodologia está baseada em conceitos como difração de raios X por materiais cristalinos, simetria, lei de Bragg e transformada de Fourier. O presente trabalho tem como finalidade apresentar as principais etapas do trabalho cristalográfico, desde a coleta de dados em monocristais, solução e refinamento da estrutura até as etapas de análise e validação do modelo cristalográfico obtido e posterior depósito no banco de dados apropriados.

A cruzaína, principal cisteíno protease do Trypanosoma cruzi, é um alvo terapêutico validado para o tratamento da doença de Chagas. Grande parte dos inibidores desta enzima é constituída de peptídeo-miméticos do tipo covalente irreversível cujo desenvolvimento, entretanto, tem sido evitado devido ao potencial efeito off target e ao perfil farmacocinético indesejável. O grupo de química medicinal NEQUIMED/ IQSC/USP vêm utilizando métodos avançados em quimioinformática para a identificação de inibidores reversíveis da cruzaína e de outras cisteíno proteases. Contudo, para que estes inibidores se desenvolvam a compostos matrizes mais eficientes, informações computacionais e estruturais de seus Modos de Interação (MOB) com a proteína alvo tornam-se fundamentais. Neste trabalho, a cristalografia de raios X foi utilizada para descrever em detalhes o MOB de três importantes inibidores reversíveis da cruzaína identificados pelo NEQUIMED: a dipeptidil-nitrila Neq0409 e os dois fragmentos moleculares Neq0147 e Neq0176. De modo a evitar a auto-proteólise experimentada pela cruzaína nativa que torna desafiadora a cristalização com inibidores de baixa afinidade como os fragmentos reversíveis, duas novas construções mutantes e inativas da cruzaína (a C25A e a C25S) foram desenvolvidas. A C25S foi validada como modelo cristalográfico representativo dado a coerência do MOB elucidado nesta enzima mutante e na cruzaína nativa para o inibidor mais estudado da cruzaína, o K777. A descrição da presença, orientação, conformação e modo de ação no sítio, além do completo padrão de interações fornecidos por estas estruturas cristalinas, validaram ortogonalmente os MOB preditos e os métodos de planejamento in silico usados no NEQUIMED, permitindo a identificação de inibidores muito mais potentes análogos ao Neq0147 e ao Neq0409. O grupo 2-acetamidotiofeno-3-carboxamida do Neq0176 e o anel heterocíclico de cinco membros baseado no 1,3,4-oxadiazol do Neq0147 foram identificados como alternativos aos tradicionais esqueletos peptídeo-miméticos. O impacto do efeito proteolítico na qualidade e na resolução de estruturas cristalográficas na cruzaína foi melhor compreendido a partir de duas estruturas de alta resolução obtidas para a cruzaína nativa em complexo com o metanotiossulfonato de metila (MMTS) e a iodoacetamida. Estes resultados permitiram compreender as bases experimentais para a cristalização de inibidores reversíveis de baixa afinidade. Todos os resultados estruturais obtidos via cristalografia de raios X neste trabalho são úteis para mapear as bases estruturais essenciais para o planejamento de futuros inibidores mais potentes e seletivos da cruzaína. Cruzain, the major Trypanosoma cruzi cysteine protease, is a validated therapeutic target for the search of new medicines for the treatment of Chagas disease. A myriad of inhibitors of this enzyme consists of covalent irreversible peptidomimetics whose development has been impaired due to potential off target effect and undesirable pharmacokinetic profile. Modern cheminformatic methods employed by The Medicinal Chemistry Group (NEQUIMED/IQSC/USP) were used to identify cruzain reversible inhibitors. Their optimization for more efficient compounds can be accomplished by the use of data and information gathered from computational and structural modes of interaction (MOB). In this doctoral thesis, the X-ray crystallography was used to describe in detail the MOB of three important new cruzain reversible inhibitors: the dipeptidil-nitrile Neq0409 and the two molecular fragmentos Neq0147 and Neq0176. In order to avoid cruzain self-proteolysis during crystallization with low affinity reversible inhibitors such as the identified fragments, two new mutant and inactive constructs of cruzain (the C25S and C25A) were designed to upholding the same properties of the wild type catalytic site. The C25S was validated as representative crystallographic model given the coherence of the MOB elucidated for the best-known and studied cruzain inhibitor, the K777. The description of the presence, orientation, conformation and mode of action at the site, besides the complete pattern of bimolecular interactions, provided by these crystalline structures, orthogonally validated the predicted in silico MOB and allowed the identification of other potent inhibitors analogous to the Neq0147 and the Neq0409. The 2-acetamidothiophene-3-carboxamide moiety (Neq0176) and heterocyclic five-membered ring based on the 1,3,4-oxadiazole (Neq0147) were thereby identified as attractive alternatives to traditional peptidomimetics. The impact of proteolytic effect on the quality and resolution of crystallographic structures in cruzain was best understood from two high-resolution structures obtained for the native cruzain in complex with methyl methanethiolsulfonate (MMTS) and iodoacetamide. These results allow the understanding of experimental basis for the crystallization with reversible inhibitors of low affinity such as fragments. All structural results obtained by X-ray crystallography together with the catalytic site depiction using GRID and SuperStar methods are useful for mapping the essential structural basis for the design of future more potent and selective cruzain inhibitors.

A series of compounds based on the dipeptidyl nitrile scaffold were synthesized and assayed for their inhibitory activity against the T. cruzi cysteine protease cruzain. Structure activity relationships (SARs) were established using three, eleven and twelve variations respectively at the P1, P2 and P3 positions. A K i value of 16 nM was observed for the most potent of these inhibitors which reflects a degree of non-additivity in the SAR. An X-ray crystal structure was determined for the ligand-protein complex for the structural prototype for the series. Twenty three inhibitors were also evaluated for their anti-trypanosomal effects and an EC50 value of 28 μM was observed for the most potent of these. Although there remains scope for further optimization, the knowledge gained from this study is also transferable to the design of cruzain inhibitors based on warheads other than nitrile as well as alternative scaffolds., Author Summary Chagas disease is a parasitic infection with high morbidity and mortality that is endemic in much of Latin America where it remains a serious public health problem. With increased migration, Chagas disease represents an emerging worldwide challenge and there is an urgent, unmet need for safe and effective medication. The available drugs to treat Chagas disease may be effective in the acute phase of the disease, but efficacy in the chronic phase remains controversial. They can cause serious side effects that lead sufferers to abandon treatment. Using a hypothesis-driven approach to molecular design and drawing on cysteine protease cruzain structural information, we have mapped structure-activity relationships for a dipeptidyl nitrile scaffold and demonstrated that compounds are competitive inhibitors, bind reversibly and bear trypanocidal activity. The binding mode revealed by the crystal structure of the protein-ligand complex for one of the inhibitors shows that binding involves the formation of a covalent bond between the catalytic cysteine and the nitrile carbon. As such, we believe that our study represents a valuable step in the search for new drugs for the treatment of a neglected disease that continues to affect the lives of millions of people.

Magnesium (Mg++), Potassium (K+) and Calcium (CA++) are important electrolytes in keeping a stable electrical status. The purpose of this study was to measure them in critically ill patients.We evaluated the electrolytes in 28 consecutive patients. Eighteen were females and 10 males with mean age of 62 +/- 5 years.The admission diagnosis in 95% of the cases was congestive heart failure. Sixty-four percent of the patients had subnormal values of Mg++, 53% subnormal values of K+, and 28% subnormal values of CA++. Fourteen percent showed lower values of the three electrolytes and 35% only of Mg++ and K+ concomitantly. Twenty-eight percent showed prolonged QTC interval. All patients with prolonged QTC interval had low Mg++ and K+ levels. Twenty five percent of the patients showed atrial fibrillation, 25% ventricular tachycardia, and 3% junctional tachycardia. The ventricular tachycardia group had more electrolyte abnormalities than those with atrial fibrillation. None of the patients received Mg++ replacement during critical management while 50% received K+ replacement.This data shows physician overlook the Importance of Mg++ and K+ deficiency in critically ill patients.

Left ventricular aneurysm (LVA) describes a region of ventricular wall that is thinner than the adjacent myocardial segments, balloons outward and exhibits either akinesis or dyskinesis. Congenital LVA is diagnosed by exclusion with a very low incidence, especially in adult patients with very few cases reported. Clinically, most congenital LVA are asymptomatic. The most common complaints are typical angina or atypical chest pain followed by syncope and heart rhythm disturbances. We describe the case of a 26-year-old-woman that presented with monomorphic sustained ventricular tachycardia as a first manifestation of congenital LVA. Successful endoventricular circular patch placement, or Dor procedure was performed. Successful substrate modification for arrhythmia development was performed and confirmed by an electrophysiological study. This would constitute the first case of this nature reported in Puerto Rico.

A multi-step cascade strategy using integrated ligand- and target-based virtual screening methods was developed to select a small number of compounds from the ZINC database to be evaluated for trypanocidal activity. Winnowing the database to 23 selected compounds, 12 non-covalent binding cruzain inhibitors with affinity values (K i) in the low micromolar range (3–60 µM) acting through a competitive inhibition mechanism were identified. This mechanism has been confirmed by determining the binding mode of the cruzain inhibitor Nequimed176 through X-ray crystallographic studies. Cruzain, a validated therapeutic target for new chemotherapy for Chagas disease, also shares high similarity with the mammalian homolog cathepsin L. Because increased activity of cathepsin L is related to invasive properties and has been linked to metastatic cancer cells, cruzain inhibitors from the same library were assayed against it. Affinity values were in a similar range (4–80 µM), yielding poor selectivity towards cruzain but raising the possibility of investigating such inhibitors for their effect on cell proliferation. In order to select the most promising enzyme inhibitors retaining trypanocidal activity for structure-activity relationship (SAR) studies, the most potent cruzain inhibitors were assayed against T. cruzi-infected cells. Two compounds were found to have trypanocidal activity. Using compound Nequimed42 as precursor, an SAR was established in which the 2-acetamidothiophene-3-carboxamide group was identified as essential for enzyme and parasite inhibition activities. The IC50 value for compound Nequimed42 acting against the trypomastigote form of the Tulahuen lacZ strain was found to be 10.6±0.1 µM, tenfold lower than that obtained for benznidazole, which was taken as positive control. In addition, by employing the strategy of molecular simplification, a smaller compound derived from Nequimed42 with a ligand efficiency (LE) of 0.33 kcal mol−1 atom−1 (compound Nequimed176) is highlighted as a novel non-peptidic, non-covalent cruzain inhibitor as a trypanocidal agent candidate for optimization., Author Summary Chagas disease (American trypanosomiasis) is a parasitic infection that kills millions of mostly poverty-stricken people in Latin America. In recent years it has also spread to nonendemic countries – the United States, Canada, Europe, Australia and Japan – as a result of immigration. The only available drugs for its treatment were introduced more than forty years ago, have low efficacy, and cause various severe side effects. This dire public health situation has prompted us to search for new small molecules to act as drug candidates to treat Chagas disease. The T. cruzi enzyme cruzain, a key biological catalyst used by the protozoan to digest host proteins, is a validated drug target for Chagas disease. By combining in silico molecular design, X-ray crystallography and biological screening, we found a new class of non-covalent small molecules that inhibit cruzain in low micromolar concentrations.

Left ventricular non-compaction cardiomyopathy (LVNC) is a rare disorder characterized by a thick myocardial wall with two distinct layers consisting of compacted and noncompacted myocardium. The major clinical manifestations of LVNC have been described as heart failure, cardiac arrhythmias, and cardioembolic events. In this report we present a case of a young woman with LVNC who presented with aborted sudden cardiac death. This is the second case of LVNC reported in Puerto Rico, but the first presenting with this complication. Recent advances in the field of cardiology allow the identification and diagnosis of this disease; thus, preventive and treatment strategies could be established for this potentially life-threatening condition. LVNC has to be considered in young patients presenting with sudden cardiac death.

Com o intuito de se conhecer a estrutura molecular e cristalina dos compostos químicos para posteriores análises físicoquímicas e estudos de aplicação, lança-se mão da cristalografia como metodologia científica, que permite conhecer a estrutura de qualquer composto químico cristalino sem nenhuma informação a priori. Esta metodologia está baseada em conceitos como difração de raios X por materiais cristalinos, simetria, lei de Bragg e transformada de Fourier. Neste trabalho são apresentados alguns dos conceitos fundamentais da cristalografia de raios X, assim como todas as etapas envolvidas no trabalho cristalográfico. Esta poderosa metodologia foi utilizada na elucidação estrutural de dois compostos orgânicos do tipo aryl-sulfonamidas e um composto análogo de chalcona do tipo retinóide obtidos sinteticamente. Os compostos 4-N[(fenil)sulfonilamidaacetofenona] e 4-N[(2,5-diclorofenil)sulfonilamida-acetofenona], cuja a diferença entre eles é a substituição de dois átomos de hidrogênio por dois átomos de cloro nas posições 2 e 5 do anel fenila no esqueleto molecular (fenil)benzenosulfonamida, foram sintetizados e caracterizados via cristalografia de raios X. Posteriormente foi estabelecida a influência da substituição destes dois átomos de cloro na arquitetura conformacional e supramolecular destes dois compostos. O outro composto sintetizado e elucidado por cristalografia de raios X, foi o (1E,4E)-1-(4-nitrofenil)-5-(2,6,6- trimetilciclohex-1-enil)-penta-1,4-dien-3-ona que apresentou uma desordem estática durante o refinamento, constatada após uma nova coleta de dados a baixa temperatura. O presente trabalho apresenta ainda a modelagem desta desordem, e toda a análise dos dados cristalográficos obtidos, geometrias moleculares e a contribuição de interações intermoleculares no arranjo supramolecular dos compostos. Os resultados oriundos de outras metodologias de elucidação estrutural complementares, também estão apresentados. In order to know the molecular and crystalline structure of chemical compounds for further physical-chemical analysis and application studies, launches hand of crystallography as a scientific methodology that allows to know the structure of any crystalline compound without any a priori information. This methodology is based on concepts such as X-ray diffraction by crystalline materials, symmetry, Bragg's law and Fourier transform. This dissertation presents some fundamental concepts of X-ray crystallography and all the steps of crystallographic methodology. This powerful methodology has been used in the structural elucidation of two organic compounds of aryl-sulphonamide and one retinoidlike analogue of chalcone, both obtained synthetically. The compounds 4-N[(phenyl)- sulphonamideacetophenone] and 4-N[(2,5-dichlorophenyl)-sulphonamideaceto phenone], in which the difference between them is the substitution of two hydrogens at positions 2 and 5 of phenyl ring by chlorine atoms in the (phenyl)benzenesulphonamide molecular framework, were synthesized and characterized by X-ray crystallography. Subsequently was established the influence of the replacement of two chlorine atoms on the conformation and crystal assembly of these two compounds. The other compound synthesized and characterized by X-ray crystallography, was the (1E,4E)-1-(4- nitrophenyl)-5-(2,6,6-trimetylciclohexenyl-1-)-penta-1,4-dien-3-one, that presented a static disorder during the refinement, confirmed after a new data collect at low temperature. This dissertation also presents the modeling of this disorder, and all the analysis of crystallographic data obtained, the molecular geometries and the and the contribution of intermolecular interactions in the crystal packing of the compounds. The results of other complementary methods for structural elucidation, are also presented. Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES

Background The improvement of in vitro maturation (IVM) protocols through the supplementation with different molecules has become an alternative to increase the culture medium efficiency. Tretinoin (TTN, all-trans retinoic acid, ATRA), is an active metabolite of vitamin A [1], that mediates cell proliferation, cell differentiation, and embryonic development process. In in vitro production embryos systems, TTN acts improving cytoplasmic maturation process in oocytes, developmental competence in early embryos, and quality in blastocysts [2]. Studies have been demonstrated the presence of a, b and g subtypes of retinoic acid receptors (RARa, RARb, RARg) for TTN in oocyte, hatched blastocysts, and cumulus cells [3]. This molecule can also be used for treatment of skin disorders and for anti-tumor treatment, so researchers have been associated TTN with polymeric nanoparticles to protect it from degradation and to improve its chemical stability and efficacy [4]. The aim of present study was to test the concentrationdependent effect of supplementation of free tretinoin (TTN) and tretinoin-loaded lipid-core nanocapsules (TTN-LNC) in bovine in vitro maturation media, and its influence in reactive oxygen species (ROS) production in two-to four-cell stage embryos. In conclusion, tretinoinloaded lipid-core nanocapsules added in in vitro maturation media highly protects embryos at early stage of development against oxidative stress. Methods The experimental groups were established, and cumulus-oocyte complexes (COCs) were matured in oocyte in vitro maturation medium supplemented with 0.25, 0.5 and 1 μM of TTN-LNC or TTN. Control groups of COCs matured without treatment and treated only with blank lipid-core-nanocapsules (LNC) were also examined. The oocytes were in vitro fertilized in order to evaluate the ROS levels in embryos produced by the different treatments. The ROS formation was evaluated in two-to four-cell stage embryos as previously described [5] with some modifications.

A diminuição das reservas de combustíveis fósseis resulta no aumento da utilização de fontes energéticas com alto teor de substâncias prejudiciais para a saúde humana e o meio ambiente. Entre estas substâncias se destaca o sulfeto de hidrogênio. A utilização de combustíveis contendo sulfeto de hidrogênio resulta na formação de gases ácidos, que afetam a camada de ozônio, e a produção de precipitações ácidas. A exposição ao gás sulfeto de hidrogênio pode ser fatal para a vida animal: humana ou não. Se faz necessário um método adequado e eficiente para o tratamento de combustíveis contendo alta concentração de sulfeto de hidrogênio. O método mais utilizado para o tratamento do sulfeto de hidrogênio consiste na oxidação controlada conhecida como processo de Claus. O presente trabalho teve como objetivo o estudo da reação química que ocorre entre o oxigênio e o sulfeto de hidrogênio, a nível molecular, em temperaturas acima de 1100 K, simulando assim a fase térmica do processo de Claus. Para este propósito foi utilizada a técnica de dinâmica molecular ab initio de Car-Parrinello juntamente com a metadinâmica. Durante a simulação, que teve o tempo aproximado de 7,4 picossegundos, foram observadas 8 reações. Dentre as reações observadas duas diferem dos mecanismos propostos na bibliografia pesquisada: a formação do HSO e a formação do HO2. A presença da molécula de ozônio no meio reacional, também, não foi relatada na bibliografia pesquisada. Através da metadinâmica realizada para a reação de formação do ozônio foi calculada a constante reacional de Arrhenius. The decline in fossil fuel reserves results in increased use of energy sources with a high content of substances harmful to human health and the environment. Among these substances is hydrogen sulphide. The use of hydrogen sulphide- containing fuels results in the formation of acid gases, which affect the ozone layer, and the production of acid precipitation. Exposure to hydrogen sulfide gas can be fatal to animal life: human or not. A suitable and efficient method is necessary for the treatment of fuels containing high concentration of hydrogen sulphide. The most widely used method for the treatment of hydrogen sulphide is the controlled oxidation known as the Claus process. The present work had as objective the study of the chemical reaction that occurs between oxygen and hydrogen sulfide, at molecular level, at temperatures above 1100 K, thus simulating the thermal phase of the Claus process. For this purpose, Car- Parrinello's ab initio molecular dynamics technique was used along with metadynamics. During the simulation, which had the approximate time of 7.4 picoseconds, 8 reactions were observed. Among the reactions observed, two differ from the mechanisms proposed in the literature: the formation of HSO and the formation of HO2. The presence of the ozone molecule in the reaction medium, too, was not reported in the researched literature. Through the metadynamics performed for the ozone formation reaction the Arrhenius reaction constant was calculated. Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES

O ritonavir é um anti-retroviral de via oral, usado juntamente com outros medicamentos para tratar o HIV/AIDS. Muitas vezes doses desse medicamento são usadas paralelamente a outros inibidores da protease e também há relatos do uso de sua combinação com outras drogas para o combate à hepatite C. Foram relatadas diferentes formas polimórficas do ritonavir dois anos após o início de sua comercialização, quando as cápsulas começaram a apresentar problemas de dissolução, consequentemente menor biodisponibilidade. Análises de raios-X evidenciaram a formação de um polimorfo menos solúvel. Fenômenos relacionados à solubilidade e biodisponibilidade de fármacos estão intimamente ligados à estrutura química dos mesmos e esta à interação das moléculas com solventes, portanto, o objetivo principal desse trabalho é avaliar os efeitos da solvatação aquosa sobre os parâmetros geométricos e eletrônicos do ritonavir utilizando como ferramenta a Dinâmica Molecular de Car-Parrinello. Os elétrons do caroço foram tratados através dos pseudopotenciais ultrasoft de Vanderbilt, e os elétrons de valência foram representados pelo conjunto de funções de base de ondas planas. A energia de corte (Ecut) adotada foi de 25 Ry e a energia de corte para a densidade de cargas (Ecutrho) adotada foi de 200 Ry. Foram controladas as temperaturas dos sistemas estudados utilizando o termostato de Nosé-Hoover em 300 k. Os resultados da simulação mostram que a hidratação induz a formação de várias pontes de hidrogênio entre os grupos hidrofílicos do ritonavir e as moléculas de água, houve também protonação de dois nitrogênios presentes no fármaco. A separação adiabática se manteve constante durante toda a simulação, garantindo que não houve trocas de energia entre o sistema iônico e eletrônico. Ritonavir is an oral antiretroviral, used together with other medicines to treat HIV / AIDS. Doses of this drug are used simultaneously with others protease inhibitors and there are also reports of the use of ritonavir with other drugs to prevent hepatitis C. They were reported different polymorphic forms of ritonavir two years after the beginning of the market, when the capsules started to show dissolution problems consequently to the lower bioavailability. X-ray analysis showed the formation of a less soluble polymorph. Phenomena related to solubility and bioavailability of drugs are closely linked to the chemical structure of the same and with the interaction of molecules with solvents, therefore, the main objective of this study is to evaluate the effects of aqueous solvation on the geometric and electronic parameters of ritonavir using as tool Molecular dynamics of Car-Parrinello. The cores of the electrons were treated through the pseudopotential ultrasoft Vanderbilt, and the valence electrons were represented by the set of plane waves basis functions. The power cut (Ecut) was adopted 25 Ry and cutting power to the charge density (Ecutrho) was adopted 200 Ry. The temperatures of the studied systems were controlled using NoséHoover thermostat at 300 K. The simulation results show that hydration induces to formation of several hydrogen bridges between ritonavir hydrophilic groups and water molecules, there were also protonation of two nitrogens present in the drug. The adiabatic separation remained constant during the simulation, ensuring that there was no exchange of energy between the ionic and electronic system.