Nanostructured Polypyrrole Powder: A Structural and Morphological Characterization

Polypyrrole (PPY) powder was chemically synthesized using ferric chloride (FeCl3) and characterized by X-ray diffraction (XRD), Le Bail Method, Fourier Transform Infrared Spectrometry (FTIR), and Scanning Electron Microscopy (SEM). XRD pattern showed a broad scattering of a semicrystalline structure composed of main broad peaks centered at 2θ = 11.4°, 22.1°, and 43.3°. Crystallinity percentage was estimated by the ratio between the sums of the peak areas to the area of amorphous broad halo due to the amorphous phase and showed that PPY has around 20 (1)%. FTIR analysis allowed assigning characteristic absorption bands in the structure of PPY. SEM showed micrometric particles of varying sizes with morphologies similar to cauliflower. Crystal data (monoclinic, space group P 21/c, a=7.1499 (2) Å, b=13.9470 (2) Å, c=17.3316 (2) Å, α=90 Å, β=61.5640 (2) Å and γ=90 Å) were obtained using the FullProf package program under the conditions of the method proposed by Le Bail. Molecular relaxation was performed using the density functional theory (DFT) and suggests that tetramer polymer chains are arranged along the “c” direction. Average crystallite size was found in the range of 20 (1) Å. A value of 9.33 × 10−9 S/cm was found for PPY conductivity

In vitro Antiplasmodial Activities of Alkaloids Isolated from Roots of Worsleya procera (Lem.) Traub (Amaryllidaceae)

A combined phytochemical, crystallographic and biological study of Worsleya procera roots was performed. Fifteen alkaloids were identified by gas chromatography mass spectrometry (GC-MS) and seven of them were isolated. The structures of the alkaloids were elucidated by spectroscopic methods, and a detailed crystallographic study of tazettine was carried out. The isolated alkaloids and the obtained extracts were tested in vitro against Plasmodium falciparum (3D7 and K1 strains) and human hepatocarcinoma cells (HepG2) to assess their antiplasmodial and cytotoxic effects, respectively. One of the isolated alkaloid derivatives, lycorine, exhibited antiplasmodial activity against both sensitive (3D7) and resistant (K1) parasite strains in the low micromolar range (half-maximal sample inhibitory concentration (IC50) values of 2.5 and 3.1 µM, respectively) and displayed a low cytotoxicity profile, with a selectivity index greater than 100. Our findings indicate that lycorine is a hit for antimalarial drug discovery. Keywords: isoquinolinic alkaloids; Amaryllidaceae; Plasmodium falciparum; lycorine; tazettin

Autonomic thermoregulatory dysfunction in neurofibromatosis type 1 Disfunção autonômica termorregulatória na neurofibromatose do tipo 1

Neurofibromatosis type 1 (NF1) is an autosomal dominant disorder, caused by mutations in a single gene (OMIM #162200, neurofibromin, 17 q11.2) affecting the development-maintenance-repair of neural and cutaneous tissues. Neurofibromatosis type 1 is the most common human monogenetic disease (1:3000, affecting nearly 80,000 Brazilian people) and it exhibits marked phenotype expression variability and an unpredictable course 5 , and both features are related to life expectancy, and quality of life. Possible mechanisms involving NF1-reduced muscle strength and aerobic capacity could be neurological abnormalities related to the neurofibromin deficiency, such as poorer motor coordination/activation, as well as lower levels of daily physical activities and motivation for exercising. Both neural disorder and reduced aerobic capacity could adversely affect thermoregulatory capacity, leading to decreased exercise performance in hot environments and heat intolerance with higher risk for heat-related injuries 6 . Despite increases in environmental temperature and/or exercise body metabolism, human internal temperature must be maintained within a small physiological range through heat dissipation, to prevent tissue ABSTRACT Objective: Neurofibromatosis type 1 (NF1) causes neural and cutaneous disorders and reduced exercise capacity. Exercise/heat exposure increasing internal temperature must be compensated by eccrine sweat function and warmed skin vasodilation. We suspected NF1 could adversely affect eccrine sweat function and/or vascular thermoregulatory responses (VTR). Methods: The eccrine sweat function and VTR of 25 NF1 volunteers (14 males, 11 females; 16-57 years old) were compared with 23 non-NF1 controls matched by sex, age, height and weight (CG). Sweating was induced by 1) pilocarpine 1% iontophoresis (PILO); and 2) by passive heating (HEAT) via the lower third of the legs being immersed in 42°C water for one hour. Previously established eccrine sweat function and VTR protocols were used. Results: The NF1 group showed: a) lower sweat rate than the CG group during PILO; b) a smaller diastolic pressure decrease; and c) higher tympanic temperatures than controls during HEAT (p < 0.05). Conclusion: Reduced sweating and vascular thermoregulatory responses suggest autonomic dysfunction in NF1 individuals. Keywords: neurofibromatosis 1; sweating; primary dysautonomias; body temperature regulation. RESUMO Objetivo: Neurofibromatose do tipo 1 (NF1) causa problemas neurais e cutâneos e diminuição da capacidade física. O aumento da temperatura interna durante exercício e exposição ao calor precisa ser compensada pela função sudorípara écrina (FSE) e aquecimento cutâneo por vasodilatação (RVT). Suspeitou-se clinicamente que a NF1 poderia prejudicar a FSE e a RVT. Métodos: A FSE e RVT de 25 voluntários com NF1 (14 homens, 11 mulheres; 16-57 anos) e de 23 sem-NF1, emparelhados por sexo, idade, estatura e peso corporal, foram medidas com protocolos validados anteriormente. A sudorese foi induzida por iontoforese com pilocarpina (PILO) e aquecimento passivo por imersão das pernas em água a 42°C durante uma hora (HEAT). Resultados: O grupo NF1 apresentou menor taxa de sudorese na situação PILO, menor redução da pressão diastólica e maior temperatura timpânica na situação HEAT (p < 0.05). Conclusão: As respostas sudorípara e vascular reduzidas sugerem disfunção autonômica nas pessoas com NF1. Palavras-chave: neurofibromatose 1; sudorese; disautonomia primária; regulação da temperatura corporal

The Facet of Human Impact: Solenopsis invicta Buren, 1972 Spreading around the Atlantic Forest

The present investigation deals with some aspects of the diversity of fire ants (Hymenoptera: Formicidae) in their native range. The Red Imported Fire Ant Solenopsis invicta is native to the tropical and subtropical inland territories of South America. In Brazil, it mainly occurs around the Pantanal region and across the Paraguay river, a region composed of grasslands which are seasonally flooded. Recent studies have evidenced this fire ant species is gradually spreading to other regions of Brazil. In the present investigation, we surveyed the molecular diversity of S. invicta populations across fragments of Atlantic Forest in Sao Paulo, Brazil, using mtDNA COI haplotypes. Fire ant nests were sampled along the highways lining the northern and southern slope sides of the mountain range Serra do Mar, SP, Brazil. Four haplotypes were identified (H1-H4), which were assessed for similarity to deposited records by other authors, revealing that the haplotypes H1 and H2 are likely of foreign origin through recent reintroduction via a marine port to the south of the Serra do Mar mountain range. On the other hand, the haplotypes H3 and H4, predominating among the inland samples from the northern side of the mountain range, were most similar to previous records from more central regions of Brazil. Haplotypes clustered into distinct supergroups, further pointing to the occurrence of two separate expansion waves of S. invicta in the region. We suggest the obtained pattern indicates the mountain range may function as a geographical barrier deferring gene flow

Production and release of heat-labile toxin by wild-type human-derived enterotoxigenic Escherichia coli

Production and release of heat-labile toxin (LT) by wild-type enterotoxigenic Escherichia coli (ETEC) strains, isolated from diarrheic and asymptomatic Brazilian children, was studied under in vitro and in vivo conditions. Based on a set of 26 genetically diverse LT+ enterotoxigenic E. coli strains, cell-bound LT concentrations varied from 49.8 to 2415 ng mL(-1). the amounts of toxin released in culture supernatants ranged from 0% to 50% of the total synthesized toxin. the amount of LT associated with secreted membrane vesicles represented < 5% of the total toxin detected in culture supernatants. ETEC strains secreting higher amounts of LT, but not those producing high intracellular levels of cell-bound toxin, elicited enhanced fluid accumulation in tied rabbit ileal loops, suggesting that the strain-specific differences in production and secretion of LT correlates with symptoms induced in vivo. However, no clear correlation was established between the ability to produce and secrete LT and the clinical symptoms of the infected individuals. the present results indicate that production and release of LT by wild-type human-derived ETEC strains are heterogeneous traits under both in vitro and in vivo growth conditions and may impact the clinical outcomes of infected individuals.Univ São Paulo, Dept Microbiol, Inst Ciencias Biomed, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Microbiol Imunol & Parasitol, São Paulo, BrazilFdn Oswaldo Cruz, Escola Nacl Saude Publ, Rio de Janeiro, BrazilUniv São Paulo, Dept Patol, Fac Med Vet & Zootecn, São Paulo, BrazilInst Butantan, Div Desenvolvimento Tecnol & Prod, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Microbiol Imunol & Parasitol, São Paulo, BrazilWeb of Scienc

Broncoespasmo induzido pelo exercício na infância

We review the concept, pathophysiology, clinical diagnosis, pulmonary function tests, and treatment of exercise-induced bronchospasm in children. Exercise-induced bronchospasm is the acute narrowing of the airway that is triggered by vigorous physical activity in individuals with airway hyperreactivity. It is characterized by several degrees of obstruction occurring some minutes after the end of exercise. A late responsemay also occur, usually in children. Exercise-induced bronchospasm in children affects up to 15% of general population, and it is more prevalent in asthmatics. Diagnosis is suggested by typical history, and confirmed by specific tests. The clinical presentation is variable. Its diagnosis is confirmed by a recorded fall in the peak expiratory flow (PEF) or forced expiratory volume in 1 second (FEV1 ) of 15% or higher after exercise, or by a decrease in the forced expiratory flow at 25-75% (FEF25-75) of 20% in relation to baseline measurements. Many theories try to explain the pathophysiology of this condition. Beta-2 agonists are the most common drugs used in the treatment of exerciseinduced bronchospasm and in prophylaxis. Mast cell stabilizing agents and leukotriene antagonists can also be used. Exercise-induced bronchospasm should be remembered in asthmatic patients that present symptoms on exercising. Although there is a large amount of informationavailable about therapeutic options, there is still much to be explored in this field of studyNeste trabalho, são revisados conceitos atuais sobre definição, fisiopatologia, diagnóstico clínico e funcional pulmonar e tratamento do broncoespasmo induzidopelo exercício em crianças. O broncoespasmo induzido pelo exercício é o estreitamento da via aérea desencadeado por atividade física em pessoas comreatividade brônquica aumentada. Caracteriza-se por vários graus de obstrução ao fluxo aéreo, ocorrendo minutos após a finalização do exercício. Pode seguir-setambém uma resposta tardia, especialmente em crianças. Atinge 15% da população geral, mais freqüentemente asmáticos. A apresentação clínica é variável. O diagnóstico é confirmado por uma queda no pico de fluxo expiratório (PFE) ou no volume expiratório final no primeiro segundo (VEF1) de 15% ou mais após o exercício, ou uma redução no fluxo expiratório forçado de 25 a 75% da capacidade vital (FEF25-75) de 20%. Várias teorias tentam explicar sua fisiopatologia. Os beta2-agonistas são, até o momento, as drogas mais usadas no tratamento e profilaxia do broncoespasmoinduzido pelo exercício. Inibidores da degranulação dos mastócitos e antagonistas dos leucotrienos também são utilizados. O broncoespasmo induzido pelo exercício deve ser especialmente lembrado naqueles pacientes asmáticos com sintomas ao exercício. Embora muito já se conheça em termos de alternativas terapêuticas, esta é uma área ainda parcialmente explorada