Prevalência e incidência da hepatite C em pacientes submetidos a transplante renal

OBJECTIVE: To detect the prevalence and the seroconversion of the anti-HCV in renal transplants, while evaluating the presence of this antibody at the time of thetransplant, and during a 1-year follow-up, as well as the possibility of transmitting the disease to the recipient of the contaminated organ.PATIENTS AND METHODS: We investigated the prevalence of anti-HCV infection in 48 kidney transplant recipients, and also in their respective donors. Serumspecimens were collected from the organ recipients right before kidney transplant, and 6 and 12 months after transplant; serum specimens were collected from donors at the time of nephroctomy. The 192 samples were stored at -20º C. The anti-HCV tests used were commercial kits based on synthetic HCV peptides (UBI), enzygnost anti-HCV (Boehringer), and Abbot HCV EIA 2nd generation. In patients with a positive anti-hepatitis C UBI test, the presence of HCV-RNA was verified by polymerase chain reaction .RESULTS: Eleven of 40 patients had positive UBI results, and 12 of 48 had positive EIA anti-HCV results before the transplant. Sixteen patients were anti-HCV positive during the 1-year follow-up. Two patients became positive after 6 months, and one after 12 months. One of these patients was also HCV-RNA positive. No transplant recipient patient with positive anti-HCV before transplant seroconverted after 1 year. Fifty percent of the patients who received a kidney were HCV-RNA positive. Three of 40 donors indicated a positive anti-HCV antibody in the UBI test, and 4 of 48 donors indicated a positive anti-HCV antibody in the Boehringer and EIA tests. Two donors were HCV-RNA positive.CONCLUSIONS: The prevalence of anti-HCV before transplant was high, and the serconversion to positive was low during the follow-up; none of the anti-HCV positive patients seroconverted; the HCV-RNA positive patients did not change to negative after transplant, which indicates the persistence of viral replication even after immunosupression; anti-HCV positive donors, even in the presence of HCV-RNA, did not transmit the infection during 1 year after transplant.OBJETIVO: Investigar a prevalência do anti-VHC em 48 receptores renais e seusrespectivos doadores.PACIENTES E MÉTODOS: Foi coletado sangue dos receptores pré-transplante, 6meses e 1 ano pós-transplante; e dos doadores, no momento da nefrectomia. As192 amostras foram conservadas a -20 °C. Os testes anti-VHC utilizados forampeptídeos sintéticos (UBI) e ELISA de segunda geração (Abbott). Nos pacientescom positividade ao anti-VHC pelo teste UBI, foi pesquisado o VHC-ARN por reaçãoem cadeia da polimerase.RESULTADOS: Onze de 40 receptores foram anti-VHC positivos pelo teste da UBIe 12 de 48 pelo teste da Abbott pré-transplante. Dezesseis pacientes apresentarampositividade ao anti-VHC no período de 1 ano pós-operatório. Dois positivaram aos6 meses e um em 1 ano. Um deles apresentou positividade também ao VHC-ARN.Nenhum paciente anti-VHC positivo seroconverteu com 1 ano de seguimento.Verificou-se a presença do VHC-ARN em 50% dos receptores renais. Três de 40doadores foram anti-VHC positivos pelo teste UBI e 4 de 48 pelo teste Abbott. Doisdoadores apresentaram positividade ao VHC-ARN.CONCLUSÕES: 1) A prevalência do anti-VHC pré-transplante foi alta, porém aseroconversão para anti-VHC positivo no seguimento de 1 ano foi baixa; 2) nenhumpaciente anti-VHC positivo seroconverteu; 3) houve manutenção da positividadeao VHC-ARN demonstrando persistência da replicação viral apesar daimunossupressão; 4) os doadores anti-VHC positivos, mesmo com a presença doVHC-ARN não transmitiram a infecção através do enxerto renal no seguimento de1 ano pós-operatório

Hepatits C incidence and prevalence in kidney transplant patients

OBJETIVO: Investigar a prevalência do anti-VHC em 48 receptores renais e seus respectivos doadores. PACIENTES E MÉTODOS: Foi coletado sangue dos receptores pré-transplante, 6 meses e 1 ano pós-transplante; e dos doadores, no momento da nefrectomia. As 192 amostras foram conservadas a -20 °C. Os testes anti-VHC utilizados foram peptídeos sintéticos (UBI) e ELISA de segunda geração (Abbott). Nos pacientes com positividade ao anti-VHC pelo teste UBI, foi pesquisado o VHC-ARN por reação em cadeia da polimerase. RESULTADOS: Onze de 40 receptores foram anti-VHC positivos pelo teste da UBI e 12 de 48 pelo teste da Abbott pré-transplante. Dezesseis pacientes apresentaram positividade ao anti-VHC no período de 1 ano pós-operatório. Dois positivaram aos 6 meses e um em 1 ano. Um deles apresentou positividade também ao VHC-ARN. Nenhum paciente anti-VHC positivo seroconverteu com 1 ano de seguimento. Verificou-se a presença do VHC-ARN em 50% dos receptores renais. Três de 40 doadores foram anti-VHC positivos pelo teste UBI e 4 de 48 pelo teste Abbott. Dois doadores apresentaram positividade ao VHC-ARN. CONCLUSÕES: 1) A prevalência do anti-VHC pré-transplante foi alta, porém a seroconversão para anti-VHC positivo no seguimento de 1 ano foi baixa; 2) nenhum paciente anti-VHC positivo seroconverteu; 3) houve manutenção da positividade ao VHC-ARN demonstrando persistência da replicação viral apesar da imunossupressão; 4) os doadores anti-VHC positivos, mesmo com a presença do VHC-ARN não transmitiram a infecção através do enxerto renal no seguimento de 1 ano pós-operatório.OBJECTIVE: To detect the prevalence and the seroconversion of the anti-HCV in renal transplants, while evaluating the presence of this antibody at the time of the transplant, and during a 1-year follow-up, as well as the possibility of transmitting the disease to the recipient of the contaminated organ. PATIENTS AND METHODS: We investigated the prevalence of anti-HCV infection in 48 kidney transplant recipients, and also in their respective donors. Serum specimens were collected from the organ recipients right before kidney transplant, and 6 and 12 months after transplant; serum specimens were collected from donors at the time of nephroctomy. The 192 samples were stored at -20º C. The anti-HCV tests used were commercial kits based on synthetic HCV peptides (UBI), enzygnost anti-HCV (Boehringer), and Abbot HCV EIA 2nd generation. In patients with a positive anti-hepatitis C UBI test, the presence of HCV-RNA was verified by polymerase chain reaction RESULTS: Eleven of 40 patients had positive UBI results, and 12 of 48 had positive EIA anti-HCV results before the transplant. Sixteen patients were anti-HCV positive during the 1-year follow-up. Two patients became positive after 6 months, and one after 12 months. One of these patients was also HCV-RNA positive. No transplant recipient patient with positive anti-HCV before transplant seroconverted after 1 year. Fifty percent of the patients who received a kidney were HCV-RNA positive. Three of 40 donors indicated a positive anti-HCV antibody in the UBI test, and 4 of 48 donors indicated a positive anti-HCV antibody in the Boehringer and EIA tests. Two donors were HCV-RNA positive. CONCLUSIONS: The prevalence of anti-HCV before transplant was high, and the serconversion to positive was low during the follow-up; none of the anti-HCV positive patients seroconverted; the HCV-RNA positive patients did not change to negative after transplant, which indicates the persistence of viral replication even after immunosupression; anti-HCV positive donors, even in the presence of HCV-RNA, did not transmit the infection during 1 year after transplant

Mass fractionation of noble gases in synthetic methane hydrate : implications for naturally occurring gas hydrate dissociation

This paper is not subject to U.S. copyright. The definitive version was published in Chemical Geology 339 (2013): 242-250, doi:10.1016/j.chemgeo.2012.09.033.As a consequence of contemporary or longer term (since 15 ka) climate warming, gas hydrates in some settings may presently be dissociating and releasing methane and other gases to the ocean–atmosphere system. A key challenge in assessing the impact of dissociating gas hydrates on global atmospheric methane is the lack of a technique able to distinguish between methane recently released from gas hydrates and methane emitted from leaky thermogenic reservoirs, shallow sediments (some newly thawed), coal beds, and other sources. Carbon and deuterium stable isotopic fractionation during methane formation provides a first-order constraint on the processes (microbial or thermogenic) of methane generation. However, because gas hydrate formation and dissociation do not cause significant isotopic fractionation, a stable isotope-based hydrate-source determination is not possible. Here, we investigate patterns of mass-dependent noble gas fractionation within the gas hydrate lattice to fingerprint methane released from gas hydrates. Starting with synthetic gas hydrate formed under laboratory conditions, we document complex noble gas fractionation patterns in the gases liberated during dissociation and explore the effects of aging and storage (e.g., in liquid nitrogen), as well as sampling and preservation procedures. The laboratory results confirm a unique noble gas fractionation pattern for gas hydrates, one that shows promise in evaluating modern natural gas seeps for a signature associated with gas hydrate dissociation.Partial support for this research was provided by Interagency Agreements DE-FE0002911 and DE-NT0006147 between the U.S. Geological Survey Gas Hydrates Project and the U.S. Department of Energy's Methane Hydrates Research and Development Program