Poly(epsilon-caprolactone)nanocapsules as carrier systems for herbicides: Physico-chemical characterization and genotoxicity evaluation

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

The effects of macromolecular and serum supplements and oxygen tension during bovine in vitro procedures on kinetics of oocyte maturation and embryo development

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

Analysis of Factor VIII polymorphic markers as a means for carrier detection in Brazilian families with haemophilia A

Haemophilia A is an X-linked, recessively inherited bleeding disorder of varying severity, which results from the deficiency of procoagulant factor VIII f(8). Linkage diagnosis using polymorphic markers in the f8 gene is widely used to detect carriers. The objective of this study was to verify the informativeness of three polymorphic markers in the Brazilian population, to evaluate the usefulness of such markers in carrier detection procedures. Sixty-three unrelated healthy volunteers and 10 haemophilic families were studied. Two microsatellite repeats and one HindIII RFLP markers were used. Carrier and non-carrier status could be determined in 80% of females investigated. Intron 13 markers presented the highest heterozygosity rate (79%) followed by intron 22 (68%) and intron 19 (57%). When all three markers were used together, linkage analysis informativeness increased significantly. We conclude that these markers are suitable for carrier detection in the Brazilian population and we recommend their use in combination to maximize diagnostic efficiency.

Impedance of carrier injection at the metal-organic interface mediated by surface states in electron-only tris(8-hydroxyquinoline) aluminium (Alq(3)) thin layers

Capacitance spectra of thin (< 200 nm) Alq(3) electron-only devices have been measured as a function of bias voltage. Capacitance spectra exhibit a flat response at high frequencies (> 10(3) Hz) and no feature related to the carrier transit time is observed. Toward low frequencies the spectra reach a maximum and develop a negative excess capacitance. Capacitance response along with current-voltage (J-V) characteristics are interpreted in terms of the injection of electrons mediated by surface states at the metal organic interface. A detailed model for the impedance of the injection process is provided that highlights the role of the filling/releasing kinetics of energetically distributed interface states. This approach connects the whole capacitance spectra to the occupancy of interface states, with no additional information about bulk trap levels. Simulations based on the model allow to derive the density of interface states effectively intervening in the carrier injection (similar to 1.5 x 10(12) cm (2)). (C) 2008 Elsevier B.V. All rights reserved.

Evaluation of Experimental Vaccination Against Newcastle Disease in Lovebirds (Agapornis roseicollis): Investigation of the State of Virus Carrier.

The aim of this study was to evaluate the importance of vaccination against Newcastle Disease (ND) in lovebirds (Agapornis roseicollis) and to investigate the state of carrier of the virus (NDV) in this species. There were used 48 lovebirds, distributed at random into 4 experimental groups: GI (Ulster 2C strain), Gil (B1 strain), Gill (LaSota strain) and GIV (non-vaccinated group). At 12 months of age, all groups were challenged with a pathogenic virus (NDV) suspension (ElD50 = 1081510.1 mL) and a group of Specific-Pathogen-Free (SPF) chicks were used as control of the virus. Cloaca) swabs from each bird were collected after 9, 14 and 21 days post-challenge for detection of genome viral excretion by Reverse Transcription Polymerase Chain Reaction RT-PCR. Lovebirds of GI, Gil and Gill did not demonstrate any signs of ND. They were refractory to the clinical disease. In lovebirds from the control group, NDV genome was detected 9 and 21 days after challenge. Therefore it was demonstrated the state of carrier of NDV by lovebirds. In birds from the vaccinated groups, genome viral excretion was not detected by RT-PCR. It was also demonstrated the importance of the vaccination in the suppression of the state of virus carrier of ND in lovebirds.

Intermolecular interactions and characterization of the novel factor Xa exosite involved in macromolecular recognition and inhibition: Crystal structure of human Gla-domainless factor Xa complexed with the anticoagulant protein NAPc2 from the hematophagous nematode Ancylostoma caninum

NAPc2, an anticoagulant protein from the hematophagous nematode Ancylostoma caninum evaluated in phase-II/IIa clinical trials, inhibits the extrinsic blood coagulation pathway by a two step mechanism, initially interacting with the hitherto uncharacterized factor Xa exosite involved in macromolecular recognition and subsequently inhibiting factor VIIa (K-i = 8.4 pM) of the factor VIIa/tissue factor complex. NAPc2 is highly flexible, becoming partially ordered and undergoing significant structural changes in the C terminus upon binding to the factor Xa exosite. In the crystal structure of the ternary factor Xa/NAPc2/selectide complex, the binding interface consists of an intermolecular antiparallel beta-sheet formed by the segment of the polypeptide chain consisting of residues 74-80 of NAPc2 with the residues 86-93 of factor Xa that is additional maintained by contacts between the short helical segment (residues 67-73) and a turn (residues 26-29) of NAPc2 with the short C-terminal helix of factor Xa (residues 233-243). This exosite is physiologically highly relevant for the recognition and inhibition of factor X/Xa by macromolecular substrates and provides a structural motif for the development of a new class of inhibitors for the treatment of deep vein thrombosis and angioplasty. (c) 2006 Elsevier Ltd. All rights reserved.

Efficiency of extrinsic and intrinsic charge-carrier photogeneration processes obtained from the steady-state photocurrent action spectra of poly(p-phenylene vinylene) derivatives

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Protein-Ion Binding Process on Finite Macromolecular Concentration. A Poisson-Boltzmann and Monte Carlo Study

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Macromolecular properties of cepacian in water and in dimethylsulfoxide

Cepacian is the exopolysaccharide produced by the majority of the so far investigated clinical strains of the Burkholderia cepacia complex. This is a group of nine closely related bacterial species that might cause serious lung infections in cystic fibrosis patients, in some cases leading to death. In this paper the aggregation ability and the conformational properties of cepacian chain were investigated to understand its role in biofilm formation. Viscosity and atomic force microscopy studies in water and in mixed (dimethylsulfoxide/water) solvent indicated the formation of double stranded molecular structures in aqueous solutions. Inter-residue short distances along cepacian chain were investigated by NOE NMR, which showed that two side chains of cepacian were not conformation ally free due to strong interactions with the polymer backbone. These interactions were attributed to hydrogen bonding and contributed to structure rigidity. (c) 2007 Elsevier Ltd. All rights reserved.

Monte Carlo and modified Tanford-Kirkwood results for macromolecular electrostatics calculations

The understanding of electrostatic interactions is an essential aspect of the complex correlation between structure and function of biological macromolecules. It is also important in protein engineering and design. Theoretical studies of such interactions are predominantly done within the framework of Debye-Huckel theory. A classical example is the Tanford-Kirkwood (TK) model. Besides other limitations, this model assumes an infinitesimally small macromolecule concentration. By comparison to Monte Carlo (MC) simulations, it is shown that TK predictions for the shifts in ion binding constants upon addition of salt become less reliable even at moderately macromolecular concentrations. A simple modification based on colloidal literature is suggested to the TK scheme. The modified TK models suggested here satisfactorily predict MC and experimental shifts in the calcium binding constant as a function of protein concentration for the calbindin D-9k mutant and calmodulin.

Characterization of PLGA microparticles as a drug carrier for 3-ethoxycarbonyl-2H-benzofuro[3,2-f]-1-benzopyran-2-one. Ultrastructural study of cellular uptake and intracellular distribution

Here we describe the application of microparticles (MPs) for the delivery and release of the drug a benzopsoralen. We also evaluated the intracellular distribution and cellular uptake of the drug by using an encapsulation technique for therapeutic optimization. MPs containing the compound 3-ethoxycarbonyl-2H-benzofuro[3,2-f]-1-benzopyran-2-one (psoralen A) were prepared by the solvent evaporation technique, and parameters such as particle size, drug encapsulation efficiency, effect of the encapsulation process on the drug's photochemistry, zeta potential, external morphology, and < i > in vitro release behavior were evaluated. The intracellular distribution of MPs as well as their uptake by tissues were monitored. Size distribution studies using dynamic ligh scattering and scanning electron microscopy revealed that the MPs are spherical in shape with a diameter of 1.4 mu m. They present low tendency toward aggregation, as confirmed by their zeta potential (+10.6 mV). The loading efficiency obtained was 75%. As a consequence of the extremely low diffusivity of the drug in aqueous medium, the drug release profile of the MPs in saline phosphate buffer (pH 7.4) was much slower than that obtained in the biological environment. Among the population of peritoneal phagocytic cells, only macrophages were able to phagocytose poly-d,l-lactic-co-glycolic acid (PLGA) MP. The use of psoralen A in association with ultraviolet light (360 nm) revealed morphological characteristics of cell damage such as cytoplasmic vesiculation, mitochondria condensation, and swelling of both the granular endoplasmatic reticulum and the nuclear membrane. These results indicate that PLGA MP could be a promising delivery system for psoralen in connection with ultraviolet irradiation therapy (PUVA).

Bone repair using mineral trioxide aggregate combined to a material carrier, associated or not with calcium hydroxide in bone defects

Mineral trioxide aggregate (MTA) is a powder aggregate containing mineral oxides with a good biological action and may facilitate the regeneration of the periodontal ligament and formation of bone. Calcium hydroxide demonstrates antibacterial properties, enhances tissue dissolution, and induces bone formation. The objective of this study was to evaluate the MTA in the bone healing process and verify if the calcium hydroxide P.A. can improve and accelerate this process. It was used forty rnale Wistar rats, which were divided into two groups, considering or not the use of calcium hydroxide P.A. solution before treatment. Thus, each one of these groups was divided in four groups with five animals each, according to the treatment and the defect filled by: animal's coagulum, monoolein gel, MTA in aqueous solution, and MTA combined with monoolein gel. After 10 days, the animals were perfused and the right hemimandibles removed for histological analysis. Statistical analysis of the data showed significant difference between all analyzed groups when it was made comparisons using or not calcium hydroxide P.A. (p < 0.0001). There was found statistical difference between the groups that was inserted or not MTA, independently the calcium hydroxide application (p < 0.05). Results showed that the MTA used was able to induce bone regeneration and had its action optimized when combined to calcium hydroxide P.A. (C) 2007 Elsevier Ltd. All rights reserved.

Macromolecular array patterns of silk gland secretion in social Hymenoptera larvae

The cocoon, produced by most holometabolous insects, is built with silk that is usually produced by the larval salivary gland. Although this silk has been widely studied in the Lepidoptera, its composition and macromolecular arrangement remains unknown in the Hymenoptera. The macromolecular array patterns of the silk in the larval salivary gland of some meliponids, wasps, and ants were analyzed with polarized-light microscopy, and they were compared with those of Bombyx mori (Lepidoptera). There is a birefringent secretion in the glandular lumen of all larvae, due to filamentous structural proteins that display anisotropy. The silk in the distal, middle and proximal regions of the secretory portion of Formicidae and Vespidae glands presented a lattice optical pattern. We found a different pattern in the middle secretory portion of the Meliponini, with a zigzag rather than a lattice pattern. This indicates that the biopolymer fibers begin their macromolecular reorganization at this glandular region, different from the Formicidae and the Vespidae, in which the zigzag optical pattern was only found at the lateral duct. Probably, the mechanism of silk production in the Hymenoptera is a characteristic inherited from a common ancestor of Vespoidea and Sphecoidea; the alterations in the pattern observed in the Meliponini could be a derived characteristic in the Hymenoptera. We found no similarity in the macromolecular reorganization patterns of the silk between the Hymenoptera species and the silkworm.