New insights regarding HCV-NS5A structure/function and indication of genotypic differences

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

SMase II, a new sphingomyelinase D from Loxosceles laeta venom gland: Molecular cloning, expression, function and structural analysis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The nucleon structure function and the quark effective potential

By considering a statistical model for the quark content of the nucleon, where the quark levels are generated by a Dirac equation with a harmonic scalar-plus-vector potential, we note that a good fit for the ratio between the structure functions of the neutron and proton, F-2(n)/F-2(p), can be obtained if different strengths are used for the effective confining potentials of the up and down quarks.

Pure spinor partition function and the massive superstring spectrum

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Tracing source and evolution of suspended particles in the Rio Negro Basin (Brazil) using chemical species of iron

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Molecular epidemiology and evolution of avian infectious bronchitis virus

Mutation and recombination processes are involved in the genetic and phenotypic variations of RNA viruses, leading to the emergence of new variant strains, and give rise to virus population diversity to be modeled by the host, particularly by the immune system, as occurred with infectious bronchitis virus (IBV) in chickens. The consequence is a continuous emergence of new IBV variants with regard to pathotypes, serotypes, and protectotypes. Nucleotide sequencing and subsequent genetic analysis of the S1 and N protein gene sequences provide a fast and accurate method to classify and predict IBV genotype, and a powerful instrument to monitor phylogenetic and epidemiological evolution of IBV variants. Despite the use of vaccination programmes, infectious bronchitis has become a serious problem in Brazil. Thus, a significant number of IBV field variants have been identified circulating in the Brazilian commercial poultries between 2000 to 2006 and more recently in Argentina. These viruses seem to be indigenous, because they demonstrated a low genetic relatedness with the majority of the reference strains from North America, Europe and Asia, but were moderately to highly related one to another. In summary, indigenous field IBV variants were evolving and circulating in the field in Brazil and Argentina, and should be considered as initial candidates for protection against current IBV infectious in chickens. However, in vitro and in vivo studies are needed to determine the pathogenicity and immunogenecity of these new isolates, before defining a new vaccine strain.

Renal function and histology after acute hemorrhage in rats under dexmedetomidine action

OBJETIVO: Cerca de 50% de indicações de diálise em insuficiência renal aguda vêm de problemas do perioperatório. Alterações na hemodinâmica intra-operatória levam a vasoconstrição renal e hipoperfusão. Estudos prévios não definiram o papel renal da dexmedetomidina em hemorragia. Foram estudados os efeitos da dexmedetomidina na função e histologia renais, em ratos, após hemorragia aguda. MÉTODOS: Estudo encoberto com 20 ratos Wistar, anestesiados com pentobarbital sódico intraperitoneal, 50 mg. kg-1, divididos aleatoriamente em 2 grupos sob sangramento de 30% da volemia: GD - dexmedetomidina iv, 3 µg. kg-1 (10 min), e infusão contínua, 3 µg. kg-1. h-1; GC - pentobarbital. Para estimar depuração renal, administraram-se para-aminohipurato e iotalamato de sódio. Atributos estudados: freqüência cardíaca, pressão arterial média, temperatura retal, hematócrito, depuração de para-aminohipurato e iotalamato, fração de filtração, fluxo sangüíneo renal, resistência vascular renal, análise histológica dos rins. RESULTADOS: em GD, houve valores menores de freqüência cardíaca, pressão arterial média e resistência vascular, mas valores maiores de depuração de iotalamato e fração de filtração. A depuração de para-aminohipurato e o fluxo sangüíneo foram similares nos grupos. As alterações histológicas foram compatíveis com isquemia e houve maior dilatação tubular em GD. CONCLUSÃO: em ratos, após hemorragia aguda, a dexmedetomidina determinou melhor função renal, porém maior dilatação tubular.

Cranial differentiation and evolution in Thrichomys apereoides (Rodentia: Echimyidae)

Thrichomys apereoides is an echimyid rodent which ranges in distribution from north-eastern and central Brazil into Paraguay, and currently five subspecies are recognized. Recent morphometric analyses of population samples formally assignable to T. a. laurentius and T. a. inermis, which occur in north-eastern Brazil, have shown that a major group of populations including both subspecies differ in cranial shape from a single population allocated to T. a. laurentius. In this study we employed mathematical models of evolutionary quantitative genetics to assess the role that random drift and selection may have played in the evolution of cranial shape differences in T. apereoides. The hypothesis of evolution due to drift was rejected and the selective forces necessary to account for shape differences were estimated. Minimum selective mortalities of the order of 10(-3) per generation were sufficient to explain the observed morphologic differentiation.

Effects of remifentanil infusion regimens on cardiovascular function and responses to noxious stimulation in propofol-anesthetized cats

Objective-To evaluate the effects of 2 remifentanil infusion regimens on cardiovascular function and responses to nociceptive stimulation in propofol-anesthetized cats.Animals-8 adult cats.Procedures-On 2 occasions, cats received acepromazine followed by propofol (6 mg/kg then 0.3 mg/kg/min, IV) and a constant rate infusion (CRI) of remifentanil (0.2 or 0.3 mu g/kg/min,IV) for 90 minutes and underwent mechanical ventilation (phase I). After recording physiologic variables, an electrical stimulus (50 V; 50 Hz; 10 milliseconds) was applied to a forelimb to assess motor responses to nociceptive stimulation. After an interval (>= 10 days), the same cats were anesthetized via administration of acepromazine and a similar infusion regimen of propofol; the remifentanil infusion rate adjustments that were required to inhibit cardiovascular responses to ovariohysterectomy were recorded (phase II).Results-In phase I, heart rate and arterial pressure did not differ between remifentanil-treated groups. From 30 to 90 minutes, cats receiving 0.3 mu g of remifentanil/kg/min had no response to noxious stimulation. Purposeful movement was detected more frequently in cats receiving 0.2 mu g of remifentanil/kg/min. In phase II, the highest dosage (mean +/- SEM) of remifentanil that prevented cardiovascular responses was 0.23 +/- 0.01 mu g/kg/min. For all experiments, mean time from infusion cessation until standing ranged from 115 to 140 minutes.Conclusions and Clinical Relevance-Although the lower infusion rate of remifentanil allowed ovariohysterectomy to be performed, a CRI of 0.3 mu g/kg/min was necessary to prevent motor response to electrical stimulation in propofol-anesthetized cats. Recovery from anesthesia was prolonged with this technique.

Relative contributions of beta-cell function and tissue insulin sensitivity to fasting and postglucose-load glycemia

We performed hyperglycemic clamps in 283 nondiabetic Caucasians and, with multiple linear regression, determined the contribution of beta-cell function and tissue insulin sensitivity to variations in glycemia and insulinemia during oral glucose tolerance tests (OGTTs). Impaired glucose tolerance (IGT) subjects had reduced insulin sensitivity(P < .02) and beta-cell function (P < .0001). Normal glucose tolerance (NGT) subjects with first-degree type 2 diabetic relatives had reduced first and second phase insulin secretion (both, P < .05), but normal insulin sensitivity(P = .37). beta-Cell function and insulin sensitivity accounted for one fourth of the variability in glucose tolerance. Fasting plasma glucose in subjects with NGT (n = 185) was a function of both phases of insulin secretion and of insulin sensitivity tall, P < .05), whereas, in IGT subjects (n = 98), it was a function of first phase insulin secretion and insulin sensitivity(P < .01). Two-hour glycemia was a function of second phase secretion and insulin sensitivity (P < .01). Fasting and 2-hour plasma insulin levels were determined by insulin sensitivity land glycemia) in NGT subjects (P < .001), but by second phase secretion in IGT (P < .001). We conclude that beta-cell function is reduced in subjects with IGT; glycemia and insulinemia are not regulated by the same mechanisms in IGT and NGT; insulin sensitivity does not contribute to insulinemia in IGT; family history of diabetes influences beta-cell function, but not insulin sensitivity in Caucasians. Copyright (C) 2000 by W.B. Saunders Company.

Chemistry and evolution of the Piperaceae

The chemistry of members of the family Piperaceae is of great interest owing to the variety of biological properties displayed. A survey of structural diversity and bioactivity reveals that groups of species specialize in the production of amides, phenylpropanoids, lignans and neolignans, benzoic acids and chromenes, alkaloids, polyketides, and a plethora of compounds of mixed biosynthetic origin. Bioassays against Cladosporium cladosporioides and C. sphaerospermun have resulted in the characterization of various amides, prenylated phenolic compounds, and polyketides as potential classes of antifungal agents. Studies on the developmental process in seedlings of Piper solmsianum have shown that phenylpropanoid are produced instead of the tetrahydrofuran lignans found in adult plants. In suspension cultures of P. cernuum and P crassinervium, phenylethylamines and alkamides predominate, whereas in the adult plants prenylpropanoids and prenylated benzoic acids are the respective major compound classes. Knowledge of the chemistry, bioactivity, and ecology of Piperaceae species provides preliminary clues for an overall interpretation of the possible role and occurrence of major classes of compounds.