Como os Estados Unidos estão utilizando a ciência para melhorar a saúde?

Aborda os avanços da política científica e tecnológica nos Estados Unidos no período recente e suas prioridades ao longo do início da administração Obama, visando alavancar o crescimento no curto prazo, assim como promover avanços técnicos e científicos de longo prazo na área da saúde.

Clinical evaluation of different epinephrine concentrations for local dental anesthesia / Avaliação clínica da epinefrina em diferentes concentrações para anestesia local odontológica

BACKGROUND AND OBJECTIVES: Clinical trials comparing lidocaine associated to different epinephrine concentrations are scarce. This study aimed at comparing cardiovascular parameters, anesthetic efficacy and level of discomfort during the injection of two 2% lidocaine solutions associated to 1:100,000 or 1:200,000 epinephrine. METHODS: Participated in this cross-sectional double blind study 30 patients (24.3±4.7 years) who were submitted to anamnesis, vital signs evaluation and baseline threshold measurement of right upper canine tooth. In each clinical session, with 15 days interval, 1.8mL of one of the anesthetic solutions were administered. Anesthetic efficacy was measured with electric stimulation and vital parameters were evaluated in three periods: 5 minutes before, during and soon after anesthesia. At the end of each session, the visual analog scale was applied to evaluate injection pain sensitivity, which was repeated 24h later. RESULTS: All volunteers had satisfactory pressure levels to carry out the trial. There has been no statistically significant differences in systolic blood pressure (p=0.33), diastolic blood pressure (p=0.1505), heart rate (p=0.9464) and oxygen saturation (p=0.9297) considering each local anesthetic solution in each moment (during and after anesthesia). Formulations of 2% lidocaine with 1:100,000 and 1:200,000 epinephrine have shown no statistical differences for all anesthetic parameters (p>0.05). CONCLUSION: Considering the volume used in this study, decreased epinephrine concentration on lidocaine solution has not affected its clinical efficacy and has not influenced cardiovascular parameters. .

JUSTIFICATIVA E OBJETIVOS: Estudos clínicos comparando o uso da lidocaína associada a diferentes concentrações de epinefrina na odontologia são escassos. O objetivo deste estudo foi comparar parâmetros cardiovasculares, eficácia anestésica e grau de desconforto durante a injeção de 2 soluções de lidocaína a 2% associadas a epinefrina 1:100.000 ou 1:200.000. MÉTODOS: Trinta pacientes (24,3±4,7 anos) foram incluídos (estudo cruzado e duplamente encoberto) e submetidos a anamnese, avaliação de sinais vitais e mensuração do limiar basal do dente canino superior direito. Em cada sessão clínica, com intervalo de 15 dias, foram administrados 1,8mL de uma das soluções anestésicas. A eficácia anestésica foi mensurada com estímulo elétrico, e os parâmetros vitais foram avaliados em 3 períodos: 5 minutos antes, durante e logo após a anestesia. Ao final de cada sessão foi aplicada a escala analógica visual para avaliação da sensibilidade dolorosa da injeção, e repetida após 24h. RESULTADOS: Todos os voluntários apresentaram níveis pressóricos satisfatórios para realização do estudo. Não houve diferenças estatisticamente significativas entre os valores de pressão arterial sistólica (p=0,33), pressão arterial diastólica (p=0,1505), frequência cardíaca (p=0,9464) e saturação de oxigênio (p=0,9297) considerando cada anestésico local em cada momento (durante e após a anestesia). As formulações de lidocaína a 2% com epinefrina a 1:100.000 e 1:200.000 não apresentaram diferença estatística para todos os parâmetros anestésicos (p>0,05). CONCLUSÃO: Considerando o volume utilizado no presente estudo, a redução da concentração da epinefrina na solução de lidocaína não afetou sua eficácia clínica e não influenciou os parâmetros cardiovasculares. .

Contrasting roles of donor and recipient TGFB1 and IFNG gene polymorphic variants in chronic kidney transplant rejection / Papéis contrastantes das variantes polimórficas dos genes TGFB1 e IFNG do doador e do receptor na rejeição crônica de transplantados renais

Objective: To assess the long-term impact (minimum of 3 years follow-up) of polymorphisms in cytokine genes in donor: recipient pairs on the results of the transplant. Methods: We compared genetic cytokine polymorphisms and the primary factors of risk for the development of chronic rejection in paired groups of renal transplant patients with and without chronic allograft nephropathy [CAN]. Results: Multivariate analysis indicated that the presence of the high-production TT genotype (codon 10) of the transforming growth factor beta-1 (TGFB1) was protective in receptors (p=0.017), contrasting with the increased risk when present in donor samples (p=0.049). On the other hand, in the case of the gamma interferon studied, the greater frequency of the high production allele was protective in the analysis of the donor group (p=0.013), increasing the risk of chronic nephropathy of the allograft when present in the recipients (p=0.036). Conclusion: Our results highlight the importance of TGFB1 genotyping in donors, and indicate that polymorphisms in the gene of this cytokine in donor cells might contribute to the development of chronic allograft nephropathy.

Objetivo: Avaliar o impacto de longo prazo (com seguimento mínimo de 2 anos) de polimorfismos em genes de citocinas em pares doador:receptor sobre os resultados do transplante. Métodos: Comparamos os polimorfismos genéticos das citocinas e os principais fatores de risco para o desenvolvimento de rejeição crônica em grupos pareados de pacientes transplantados renais com e sem nefropatia crônica do aloenxerto [CAN]. Resultados: A análise multivariada indicou que a presença do genótipo TT (códon 10) de alta produção do fator de crescimento transformador beta-1 (TGFB1) era protetor nos receptores (p=0,017), em contraste com o risco aumentado quando presente nas amostras de doadores (p=0,049). Por outro lado, no caso do interferon gama estudado, a maior frequência do alelo de alta produção foi protetora na análise do grupo de doadores (p=0,013), mas aumentava o risco de nefropatia crônica do aloenxerto quando presente nos receptores (p=0,036). Conclusão: Nossos resultados ressaltam a importância da genotipagem de TGFB1 também em doadores, e indicam que polimorfismos no gene desta citocina em células do doador podem contribuir no desenvolvimento da nefropatia crônica do aloenxerto.

Contrasting roles of donor and recipient TGFB1 and IFNG gene polymorphic variants in chronic kidney transplant rejection.

OBJECTIVE: To assess the long-term impact (minimum of 3 years follow-up) of polymorphisms in cytokine genes in donor:recipient pairs on the results of the transplant. METHODS: We compared genetic cytokine polymorphisms and the primary factors of risk for the development of chronic rejection in paired groups of renal transplant patients with and without chronic allograft nephropathy [CAN]. RESULTS: Multivariate analysis indicated that the presence of the high-production TT genotype (codon 10) of the transforming growth factor beta-1 (TGFB1) was protective in receptors (p=0.017), contrasting with the increased risk when present in donor samples (p=0.049). On the other hand, in the case of the gamma interferon studied, the greater frequency of the high production allele was protective in the analysis of the donor group (p=0.013), increasing the risk of chronic nephropathy of the allograft when present in the recipients (p=0.036). CONCLUSION: Our results highlight the importance of TGFB1 genotyping in donors, and indicate that polymorphisms in the gene of this cytokine in donor cells might contribute to the development of chronic allograft nephropathy.

Diversity of physiological cell reactivity to heat shock protein 60 in different mouse strains.

Heat shock proteins (Hsp) are families of highly conserved molecules and immunodominant antigens in some infections and in autoimmune diseases. Some reports suggest that different regions of the Hsp60 molecule induce distinct immune responses. However, there are no reports comparing physiological T-cell reactivity to Hsp60 in mice. In this study, we have analyzed T-cell proliferation and cytokine production induced by Hsp60, under physiological conditions, in three mouse strains bearing distinct major histocompatibility complex (MHC) backgrounds. Proliferative response predominantly was found in C57BL/6 mice, mostly induced by N-terminal and intermediate Hsp60 peptides (P < 0.0001). Interferon-gamma (IFNgamma) production was broadly induced by different regions of Hsp60 in all three mouse strains, although response was focused in different peptide groups in each strain. We did not observe an exclusive Th1 or Th2 cytokine profile induced by any particular region of Hsp60. However, we identified a strain hierarchy in IL-10 production induced by Hsp60 peptides from different regions, mostly detected in C3H/HePas, and in BALB/c, but not in C57BL/6 mice. In contrast, IL-4 production only was induced by the intermediate and C-terminal region peptides in both C3H/HePas and BALB/c mice. Our data give original information on physiological cellular reactivity to Hsp60. We also have identified peptides with the capacity to induce the production of anti-inflammatory cytokines, bringing perspectives for their use in immunotherapy of chronic inflammatory diseases and allograft rejection.

Mother-child immunological interactions in early life affect long-term humoral autoreactivity to heat shock protein 60 at age 18 years.

The presence of anti-heat shock protein 60 (Hsp60) antibodies in healthy individuals and the association of these antibodies with diseases such as arthritis and atherosclerosis are well documented. However, there is limited population-level data on interindividual variation in anti-Hsp60 levels. We investigated the influence of early-life factors on IgG reactivity to human Hsp60 at age 18 years. A population-based prospective birth cohort study included 5914 births in the city of Pelotas, Brazil, in 1982. Early-life exposures were documented during home visits in childhood. In 2000, 79% of all males in the cohort were traced. Sera from a systematic 20% sample (411 subjects) were analyzed. Anti-Hsp60 total IgG reactivity was determined by ELISA. Data were analyzed using analysis of variance and generalized linear models. Anti-Hsp60 reactivity was lognormally distributed and showed a significant direct correlation with low birthweight (p=0.039) and total duration of breastfeeding (p=0.018), of which only the latter remained significant after adjustment for potential confounders. Reactivity was not associated with asthma, pneumonia, diarrhea, or early-life malnutrition. Mother-child immunological interactions, rather than infection/disease factors seem to be associated with reactivity to Hsp60 later in life. This is in agreement with the hypothesis that maternal antibodies influence future antibody profile.

Humanization of the anti-CD18 antibody 6.7: an unexpected effect of a framework residue in binding to antigen.

Humanization of monoclonal antibodies by complementary determinant region (CDR)-grafting has become a standard procedure to improve the clinical usage of animal antibodies. However, antibody humanization may result in loss of activity that has been attributed to structural constraints in the framework structure. In this paper, we report the complete humanization of the 6.7 anti-human CD18 monoclonal antibody in a scFv form. We used a germline-based approach to design a humanized VL gene fragment and expressed it together with a previously described humanized VH. The designed humanized VL has only 14 mutations compared to the closest human germline sequence. The resulting humanized scFv maintained the binding capacity and specificity to human CD18 expressed on the cell surface of peripheral blood mononuclear cells (PBMC), and showed the same pattern of staining T-lymphocytes sub-populations, in comparison to the original monoclonal antibody. We observed an unexpected effect of a conserved mouse-human framework position (L37) that hinders the binding of the humanized scFv to antigen. This paper reveals a new framework residue that interferes with paratope and antigen binding and also reinforces the germline approach as a successful strategy to humanize antibodies.

Angiostatin-like molecules are generated by snake venom metalloproteinases.

Angiostatin is a plasminogen-derived anti-angiogenic factor composed of its first four kringle structures. This molecule is generated by proteolytic cleavage of plasminogen by some proteolytic enzymes in vitro. Since venoms of viper snakes are a rich source of both serine- and metalloproteinase, we hypothesized that angiostatin-like polypeptides could be generated during the envenomation after snake bites and play a pathophysiological role in the local tissue damage and regeneration. Our results showed that crude venoms from several species of Bothrops snakes were able to generate angiostatin-like polypeptides and purified metalloproteinases but not serine proteinases from Bothrops jararaca and Bothrops moojeni venoms were responsible for their generation in vitro. The putative plasminogen cleavage sites by the crude venoms and purified proteinases were determined by N-terminal amino acid sequencing of the angiostatin-like molecules. Angiostatin-like peptides derived from human plasminogen digestion by jararhagin, a metalloproteinase isolated from B. jararaca venom, inhibited endothelial cell proliferation in vitro. These results indicate that angiostatin-like molecules can be generated upon snakebite envenomations and may account for the poor and incomplete regenerative response observed in the damaged tissue.