Influence of the gravitational radius on asymptotic behavior of the relativistic Sitnikov problem.

The Sitnikov problem is a classical problem broadly studied in physics which can represent an illustrative example of chaotic scattering. The relativistic version of this problem can be attacked by using the post-Newtonian formalism. Previous work focused on the role of the gravitational radius λ on the phase space portrait. Here we add two relevant issues on the influence of the gravitational radius in the context of chaotic scattering phenomena. First, we uncover a metamorphosis of the KAM islands for which the escape regions change insofar as λ increases. Second, there are two inflection points in the unpredictability of the final state of the system when λ≃0.02 and λ≃0.028. We analyze these inflection points in a quantitative manner by using the basin entropy. This work can be useful for a better understanding of the Sitnikov problem in the context of relativistic chaotic scattering. In addition, the described techniques can be applied to similar real systems, such as binary stellar systems, among others.

Characterization and Pharmacokinetics of Triamcinolone Acetonide-Loaded Liposomes Topical Formulations for Vitreoretinal Drug Delivery.

PURPOSE: To achieve a safer alternative to intravitreal injection of corticosteroids, we developed and characterized triamcinolone acetonide-loaded liposomes formulations (TA-LFs) to be used topically for vitreoretinal drug delivery. METHODS: Four different 0.2% TA-LFs (TA-LF1 to TA-LF4) were generated and submitted to physicochemical characterization. Posteriorly, an ex vivo diffusion assay was performed using rabbit corneas as membranes. Finally, concentrations of triamcinolone acetonide (TA) were determined by high-performance liquid chromatography in ocular tissues from New Zealand white rabbits after multiple topical doses of TA-LF2 (6 times per day, 14 days). In addition, toxicity and tolerability of TA-LF2 was evaluated by cell viability assay and eye examination of study animals, respectively. RESULTS: TA-LF2 was the most stable formulation maintaining a stable hidrogenion potential (pH) at 30 and 40°C and even improving encapsulation with higher temperature. TA-LF2 and TA-LF3 presented the best diffusion performance in vitro reaching the highest TA concentrations after 8 h of follow-up. In vivo diffusion and pharmacokinetics analysis showed that concentrations of TA in retina and vitreous reached the highest peak at 12 h after topical administration of TA-LF2 (252.10 ± 90.00 ng/g and 32.6 ± 10.27 ng/g, respectively) and subsequently decline to 24.0 ± 11.72 ng/g and 19.5 ± 13.14 ng/g, respectively, at 14 days of follow-up. Finally, cell viability was unaffected by TA-LF2, and no increase in intraocular pressure nor ocular alterations were observed after topical administration of this formulation in rabbits. CONCLUSION: TA-loaded liposomes, administered topically, can deliver TA in the vitreous cavity and reach the retina efficiently.

The Genotype of the Donor for the (GT)n Polymorphism in the Promoter/Enhancer of FOXP3 Is Associated with the Development of Severe Acute GVHD but Does Not Affect the GVL Effect after Myeloablative HLA-Identical Allogeneic Stem Cell Transplantation.

The FOXP3 gene encodes for a protein (Foxp3) involved in the development and functional activity of regulatory T cells (CD4+/CD25+/Foxp3+), which exert regulatory and suppressive roles over the immune system. After allogeneic stem cell transplantation, regulatory T cells are known to mitigate graft versus host disease while probably maintaining a graft versus leukemia effect. Short alleles (≤(GT)15) for the (GT)n polymorphism in the promoter/enhancer of FOXP3 are associated with a higher expression of FOXP3, and hypothetically with an increase of regulatory T cell activity. This polymorphism has been related to the development of auto- or alloimmune conditions including type 1 diabetes or graft rejection in renal transplant recipients. However, its impact in the allo-transplant setting has not been analyzed. In the present study, which includes 252 myeloablative HLA-identical allo-transplants, multivariate analysis revealed a lower incidence of grade III-IV acute graft versus host disease (GVHD) in patients transplanted from donors harboring short alleles (OR = 0.26, CI 0.08-0.82, p = 0.021); without affecting chronic GVHD or graft versus leukemia effect, since cumulative incidence of relapse, event free survival and overall survival rates are similar in both groups of patients.

Local predictability and nonhyperbolicity through finite Lyapunov exponent distributions in two-degrees-of-freedom Hamiltonian systems.

By using finite Lyapunov exponent distributions, we get insight into both the local and global properties of a dynamical flow, including its nonhyperbolic behavior. Several distributions of finite Lyapunov exponents have been computed in two prototypical four-dimensional phase-space Hamiltonian systems. They have been computed calculating the growth rates of a set of orthogonal axes arbitrarily pointed at given intervals. We analyze how such distributions serve or not for tracing the orbit nature and local flow properties such as the unstable dimension variability, as the axes are allowed or not to tend to the largest stretching direction. The relationship between the largest and closest to zero exponent distribution is analyzed. It shows a linear dependency at short intervals, related to the number of degrees of freedom of the system. Finally, the hyperbolicity indexes, associated to the shadowing times, are calculated. They provide interesting information at very local scales, even when there are no Gaussian distributions and the values cannot be regarded as random variables.

Detecção precoce de ototoxicidade usando emissões otoacústicas produtivas de distorção / Ototoxicity early detection using distortion product otoacoustic emissions

Introdução: Os aminoglicosídeos são potencialmente ototóxicos, sendo que a monitorização tradicional detecta ototoxicidade quando a lesão já aconteceu. Objetivo: Estudamos prospectivamente a audição de pacientes que recebiam amicacina, usando audiometria tonal liminar (ATL) e emissões otoacústicas, produtos de distorção (EOA-PD), visando a suspeita precoce de ototoxicidade e sua prevenção. Forma de estudo: Prospectivo randomizado. Material e método: Avaliamos, com ATL, 29 pacientes em tratamento com amicacina, para detectar alterações audiométricas. Desses 29 pacientes, três tiveram alteração na ATL em 6 e/ou 8 kHz (10,34 por cento) - um com alteração bilateral; os outros dois, unilateral (quatro ouvidos), todos assintomáticos. Realizamos EOA-PD, para estudar a função coclear. Dos 29 pacientes (58 ouvidos), nove (18 ouvidos) foram afastados do estudo por não completarem as testagens das EOA-PD, ficando 20 pacientes (40 ouvidos) para análise. Resultados: Não encontramos alterações significativas nas respostas das EOA-PD durante o vale e o pico sérico da amicacina, como esperado. Quando comparados os ouvidos com e sem alterações audiométricas, as variações das respostas não foram significativas em 1, 2 e 4 kHz; no entanto, em 6 e 8 kHz mostraram diferenças significativas (p<0,05). As respostas das EOA-PD nos ouvidos com ATL normal apresentaram incrementos mais do que quedas; e o contrário aconteceu nos ouvidos que apresentaram ATL alterada, ou seja: houve mais quedas do que incrementos. Conclusões: a ototoxicidade pode ser monitorada eficazmente com EOA-PD durante a administração da droga, independentemente do horário da sua administração; os incrementos nas respostas poderiam ser um sinal precoce de ototoxicidade por aminoglicosídeos.

Resultados preliminares do efeito do antibiótico tópico no controle da dor pós laup / Preliminary Results of Topic Antibiotic Effect in the Post LAUP Pain Control

A LAUP (Laser assisted uvulopalatoplasty) é uma técnica já reconhecida para tratar o ronco e o síndrome de apnéia obstrutiva do sono leve. Desde o início da LAUP, a dor tem sido o principal problema no pós operatório. O laser produz uma vaporização térmica superficial na mucosa palatal, onde desenvolve um processo inflamatório agudo, que passa a ser colonizada e infectada por bactérias residentes na orofaringe. Objetivo: Estudara efetividade do antibiótico tópico no controle da dor pós-operatória em pacientes operados de LAUP, associado com esquemas de analgesia tradicional. Material e método: Avaliamos prospectivamente 28 pacientes com uma idade média de 47 anos, que dividimos em dois grupos: um grupo controle: 15 pacientes, que receberam diclofenaco por via intramuscular, continuando pela via oral com diclofenaco e dipirona, benzocaina em spray e gargarejos freqüentes; um grupo problema: 13 pacientes, que receberam idêntica medicação analgésica sistêmica e tópica, à qual foi adicionada um spray de rifocina tópica, a ser aplicada no local da cirurgia por 10 dias. Resultados: observamos diferenças em todos os parâmetros analisados entre o grupo controle e problema; no grupo problema, registramos uma dor intermitente e de menor intensidade, um maior tempo no início, pouca interferência com a alimentação habitual e um menor tempo de duração dessa dor, quando em comparação com o grupo controle. Conclusão: O tratamento com antibiótico tópico associado à medicação analgésica e antiinflamatória é útil no controle da dor pós-LAUP pelo domínio do processo infeccioso que se forma no local da cirurgia.

LAUP (Laser assisted uvulopalatoplasty) is an already recognized technique to treat snoring and mild obstructive sleep apnea syndrome. Since the beginning of this procedure, pain has been the main problem in the post operative period. Laser produce a superficial termal vaporization of the soft palate mucosa and leads to an acute inflamatory process with secondary bacterial colonization and infection by the normal orofaringeal flora. Aim: We studied the effec-tivaness of topic antibiotic in the post operative pain control of the patients submitted to LAUP patients. Material and methods: We assessed prospectively 28 patients with mean age of 47 years old, divided into 2 groups: A control group of 15 patients received 75 mg. of potasium diclofenac (intramuscular) continuing post operatively with oral potasium diclofenac and dipirona, benzocaine spray and frequents garglings. The problem group of 13 patients received topic and sistemic analgesic medication and garglings similar to the control group. It was added to the benzocaine spray, rifocin spray, admistred on the operated area during 10 days. Results: We observed diferences in all of the analized parameters. In the problem group an intermitent and a lesser pain level was registred with, late begining and little influence with the habitual nourishment than the control group. Conclusion: A topic antibiotic treatment associated to analgesic and antinflamatory medication is usefull to control the post LAUP pain, reducing the infectares process produced on the operatedt area.