Conservation of hepatitis C virus nonstructural protein 3 amino acid sequence in viral isolates during liver transplantation

As a consequence of selective pressure exerted by the immune response during hepatitis C virus (HCV) infection, a high rate of nucleotide mutations in the viral genome is observed which leads to the emergence of viral escape mutants. The aim of this study was to evaluate the evolution of the amino acid (aa) sequence of the HCV nonstructural protein 3 (NS3) in viral isolates after liver transplantation. Six patients with HCV-induced liver disease undergoing liver transplantation (LT) were followed up for sequence analysis. Hepatitis C recurrence was observed in all patients after LT. The rate of synonymous (dS) nucleotide substitutions was much higher than that of nonsynonymous (dN) ones in the NS3 encoding region. The high values of the dS/dN ratios suggest no sustained adaptive evolution selection pressure and, therefore, absence of specific NS3 viral populations. Clinical genotype assignments were supported by phylogenetic analysis. Serial samples from each patient showed lower mean nucleotide genetic distance when compared with samples of the same HCV genotype and subtype. The NS3 samples studied had an N-terminal aa sequence with several differences as compared with reference ones, mainly in genotype 1b-infected patients. After LT, as compared with the sequences before, a few reverted aa substitutions and several established aa substitutions were observed at the N-terminal of NS3. Sites described to be involved in important functions of NS3, notably those of the catalytic triad and zinc binding, remained unaltered in terms of aa sequence. Rare or frequent aa substitutions occurred indiscriminately in different positions. Several cytotoxic T lymphocyte epitopes described for HCV were present in our 1b samples. Nevertheless, the deduced secondary structure of the NS3 protease showed a few alterations in samples from genotype 3a patients, but none were seen in 1b cases. Our data, obtained from patients under important selective pressure during LT, show that the NS3 protease remains well conserved, mainly in HCV 3a patients. It reinforces its potential use as an antigenic candidate for further studies aiming at the development of a protective immune response.

Contributions of Non-consumptive Wildlife Tourism to Conservation

Wildlife tourism has the potential to contribute to conservation through a variety of mechanisms. This chapter presents a preliminary assessment of the extent to which this potential is currently being realised, comparing tourism based on viewing of animals in captive settings (with a focus on federated zoos) with that in free-ranging situations (wildlife watching). The key mechanisms involved are: direct wildlife management and research; use of income derived from wildlife tourism to fund conservation; education of visitors to behave in a more conservation-friendly manner; political lobbying in support of conservation; and provision of a socio-economic incentive for conservation. All of these occur in at least some zoos and wildlife-watching situations, and collectively the contribution of non-consumptive wildlife tourism to conservation is significant, though impossible to quantify. The key strengths of the zoo sector in this regard are its inputs into captive breeding and its potential to educate large numbers of people. in contrast, wildlife watching provides significant socio-economic incentives for conservation of natural habitats. There seem to be significant opportunities for expanding the role of non-consumptive wildlife tourism in conservation.

Comparative effects of wavelengths of low-power laser in regeneration of sciatic nerve in rats following crushing lesion

Peripheral nerves are structures that, when damaged, can result in significant motor and sensory disabilities. Several studies have used therapeutic resources with the aim of promoting early nerve regeneration, such as the use of low-power laser. However, this laser therapy does not represent a consensus regarding the methodology, thus yielding controversial conclusions. The objective of our study was to investigate, by functional evaluation, the comparative effects of low-power laser (660 nm and 830 nm) on sciatic nerve regeneration following crushing injuries. Twenty-seven Wistar rats subjected to sciatic nerve injury were divided into three groups: group sham, consisting of rats undergoing simulated irradiation; a group consisting of rats subjected to gallium-aluminum-arsenide (GaAlAs) laser at 660 nm (10 J/cm(2), 30 mW and 0.06 cm(2) beam), and another one consisting of rats subjected to GaAlAs laser at 830 nm (10 J/cm(2), 30 mW and 0.116 cm(2)). Laser was applied to the lesion for 21 days. A sciatic functional index (SFI) was used for functional evaluation prior to surgery and on days 7, 14, and 21 after surgery. Differences in SFI were found between group 660 nm and the other ones at the 14th day. One can observe that laser application at 660 nm with the parameters and methods utilised was effective in promoting early functional recovery, as indicated by the SFI, over the period evaluated.

LOCAL LOW POWER LASER IRRADIATION ACCELERATES THE REGENERATION OF THE FIBULAR NERVE IN RATS

Objective: To study the influence of low power GaAsAl laser irradiation on the regeneration of a peripheral nerve, following a controlled crush injury. Material and methods: The right common fibular nerve of 30 Wistar rats was submitted to a crush injury with an adjustable load forceps (5 000 g, 10 minutes of application). The animals were divided into three groups (n=10), according to the postoperative procedure (no irradiation; sham irradiation; effective irradiation). Laser irradiation (830 nm wave-length; 100 mW emission power; continuous mode; 140 J/cm(2)) was started on the first postoperative day and continued over 21 consecutive days. Body mass, time spent on the walking track and functional peroneal index (PFI) were analyzed based on the hind footprints, both preoperatively and on the 21st postoperative day. Results: Walking time and PFI significantly improved in the group that received effective laser irradiation, despite the significant gain in body mass between the pre- and post-operative periods. Conclusion: Low Power GaAsAl laser irradiation, with the parameters used in our study, accelerated and improved fibular nerve regeneration in rats.