Risk factors for Chagas` disease reactivation after heart transplantation

Background: Chagas` disease is the illness caused by the protozoan Trypanosoma cruzi and it is still endemic in Latin America. Heart transplantation is a therapeutic option for patients with end-stage Chagas` cardiomyopathy. Nevertheless, reactivation may occur after transplantation, leading to higher morbidity and graft dysfunction. This study aimed to identify risk factors for Chagas` disease reactivation episodes. Methods: This investigation is a retrospective cohort study of all Chagas` disease heart transplant recipients from September 1985 through September 2004. Clinical, microbiologic and histopathologic data were reviewed. Statistical analysis was performed with SPSS (version 13) software. Results: Sixty-four (21.9%) patients with chronic Chagas` disease underwent heart transplantation during the study period. Seventeen patients (26.5%) had at least one episode of Chagas` disease reactivation, and univariate analysis identified number of rejection episodes (p = 0.013) and development of neoplasms (p = 0.040) as factors associated with Chagas` disease reactivation episodes. Multivariate analysis showed that number of rejection episodes (hazard ratio = 1.31; 95% confidence interval [CI]: 1.06 to 1.62; p = 0.011), neoplasms (hazard ratio = 5.07; 95% CI: 1.49 to 17.20; p = 0.009) and use of mycophenolate mofetil (hazard ratio = 3.14; 95% CI: 1.00 to 9.84; p = 0.049) are independent determinants for reactivation after transplantation. Age (p = 0.88), male gender (p = 0.15), presence of rejection (p = 0.17), cytomegalovirus infection (p = 0.79) and mortality after hospital discharge (p = 0.15) showed no statistically significant difference. Conclusions: Our data suggest that events resulting in greater immunosuppression status contribute to Chagas` disease reactivation episodes after heart transplantation and should alert physicians to make an early diagnosis and perform pre-emptive therapy. Although reactivation led to a high rate of morbidity, a low mortality risk was observed.

Galectin-3 plays a modulatory role in the life span and activation of murine neutrophils during early Toxoplasma gondii infection

Galectins are beta-galactoside-binding lectins involved in several biological processes and galectin-3 (Gal-3) is related to modulation of immune and inflammatory responses. This study aimed to evaluate the role of Gal-3 in the life span and biological functions of murine neutrophils during in vitro infection by virulent Toxoplasma gondii RH strain. Inflammatory peritoneal neutrophils (N phi) from C57BL/6 wildtype (WT) and Gal-3 knockout (KO) mice were cultured in the presence or absence of parasites and analyzed for phosphatidylserine (PS) exposure and cell death using Annexin-V and propidium iodide staining, and cell viability by MU assay. Cell toxicities determined by lactate dehydrogenase (LDH), degranulation by lysozyme release, and cytokine production were measured in NO culture supernatants. Phorbol myristate acetate (PMA)- or zymosan-dependent reactive oxygen species (ROS) were measured in N phi cultures. Our results demonstrated that Gal-3 is involved in the increase of the viable Not. number and the decrease of PS exposure and cell death following T. gondii infection. We also observed that Gal-3 downmodulates gondii-induced N phi toxicity as well as N phi degranulation regardless of infection. Furthermore, Gal-3 expression by N phi was associated with increased levels of IL-10 in the beginning and decreased levels of TNF-alpha later on, regardless of parasite infection, as well as with decreased levels of IL-6 and increased IL-12 levels, following early parasite infection. Our results also showed that Gal-3 suppresses PMA- but not zymosan-induced ROS generation in N phi following T. gondii infection. In conclusion, Gal-3 plays an important modulatory role by interfering in N phi life span and activation during early T gondii infection. (C) 2009 Elsevier GmbH. All rights reserved.

Lack of galectin-3 alters the balance of innate immune cytokines and confers resistance to Rhodococcus equi infection

Galectin-3 is a p-galactoside-binding lectin implicated in the fine-tuning of innate immunity. Rhodococcus equi, a facultative intracellular bacterium of macrophages, causes severe granulomatous bronchopneumonia in young horses and immunocompromised humans. The aim of this study is to investigate the role of galectin-3 in the innate resistance mechanism against R. equi infection. The bacterial challenge of galectin-3-deficient mice (gal3(-/-)) and their wild-type counterpart (gal3(+/+)) revealed that the LD50 for the gal3(-/-) mice was about seven times higher than that for the gal3(+/+) mice. When challenged with a sublethal dose, gal3(-/-) mice showed lower bacteria counts and higher production of IL-12 and IFN-gamma production, besides exhibiting a delayed although increased inflammatory reaction. Gal3(-/-) macrophages exhibited a decreased frequency of bacterial replication and survival, and higher transcript levels of IL-1 beta, IL-6, IL-10, TLR2 and MyD88. R. equi-infected gal3(+/+) macrophages showed decreased expression of TLR2, whereas R. equi-infected gal3(-/-) macrophages showed enhanced expression of this receptor. Furthermore, galectin-3 deficiency in macrophages may be responsible for the higher IL-1 beta serum levels detected in infected gal3(-/-) mice. Therefore galectin-3 may exert a regulatory role in innate immunity by diminishing IL-1 beta production and thus affecting resistance to R. equi infection.

Baseline hippocampal theta oscillation speeds correlate with rate of operant task acquisition

Many lines of evidence indicate that theta rhythm, a prominent neural oscillatory mode found in the mammalian hippocampus, plays a key role in the acquisition, processing, and retrieval of memories. However, a predictive neurophysiological feature of the baseline theta rhythm that correlates with the learning rate across different animals has yet to be identified. Here we show that the mean theta rhythm speed observed during baseline periods of immobility has a strong positive correlation with the rate at which rats learn an operant task. This relationship is observed across rats, during both quiet waking (r=0.82; p<0.01) and paradoxical sleep (r=0.83; p<0.01), suggesting that the basal theta frequency relates to basic neurological processes that are important in the acquisition of operant behavior. (c) 2008 Elsevier B.V. All rights reserved.

Molecular Characterization, Distribution, and Dynamics of Hepatitis C Virus Genotypes in Blood Donors in Colombia

Hepatitis C virus (HCV) is a frequent cause of acute and chronic hepatitis and a leading cause for cirrhosis of the liver and hepatocellular carcinoma. HCV is classified in six major genotypes and more than 70 subtypes. In Colombian blood banks, serum samples were tested for anti-HCV antibodies using a third-generation ELISA. The aim of this study was to characterize the viral sequences in plasma of 184 volunteer blood donors who attended the ""Banco Nacional de Sangre de la Cruz Roja Colombiana,`` Bogota, Colombia. Three different HCV genomic regions were amplified by nested PCR. The first of these was a segment of 180 bp of the 5`UTR region to confirm the previous diagnosis by ELISA. From those that were positive to the 5`UTR region, two further segments were amplified for genotyping and subtyping by phylogenetic analysis: a segment of 380 bp from the NS5B region; and a segment of 391 bp from the E1 region. The distribution of HCV subtypes was: 1b (82.8%), 1a (5.7%), 2a (5.7%), 2b (2.8%), and 3a (2.8%). By applying Bayesian Markov chain Monte Carlo simulation, it was estimated that HCV-1b was introduced into Bogota around 1950. Also, this subtype spread at an exponential rate between about 1970 to about 1990, after which transmission of HCV was reduced by anti-HCV testing of this population. Among Colombian blood donors, HCV genotype 1b is the most frequent genotype, especially in large urban conglomerates such as Bogota, as is the case in other South American countries. J. Med. Virol. 82: 1889-1898, 2010. (C) 2010 Wiley-Liss, Inc.

Phylogenetic Analysis of Hepatitis B Virus Genotype F Complete Genome Sequences From Chilean Patients With Chronic Infection

Molecular epidemiological data concerning the hepatitis B virus (HBV) in Chile are not known completely. Since the HBV genotype F is the most prevalent in the country, the goal of this study was to obtain full HBV genome sequences from patients infected chronically in order to determine their subgenotypes and the occurrence of resistance-associated mutations. Twenty-one serum samples from antiviral drug-naive patients with chronic hepatitis B were subjected to full-length PCR amplification, and both strands of the whole genomes were fully sequenced. Phylogenetic analyses were performed along with reference sequences available from GenBank (n = 290). The sequences were aligned using Clustal X and edited in the SE-AL software. Bayesian phylogenetic analyses were conducted by Markov Chain Monte Carlo simulations (MCMC) for 10 million generations in order to obtain the substitution tree using BEAST. The sequences were also analyzed for the presence of primary drug resistance mutations using CodonCode Aligner Software. The phylogenetic analyses indicated that all sequences were found to be the HBV subgenotype F1b, clustered into four different groups, suggesting that diverse lineages of this subgenotype may be circulating within this population of Chilean patients. J. Med. Virol. 83: 1530-1536, 2011. (C) 2011 Wiley-Liss, Inc.

Molecular epidemiology and genetic diversity of hepatitis B virus genotype E in an isolated Afro-Colombian community

Hepatitis B virus (HBV) infection is a significant public health concern with 350 million chronic carriers worldwide. Eight HBV genotypes (A-H) have been described so far. Genotype E (HBV/E) is widely distributed in West Africa and has rarely been found in other continents, except for a few cases in individuals with an African background. In this study, we characterized HBV genotypes in Quibdo, Colombia, by partial S/P gene sequencing, and found, for the first time, HBV/E circulating in nine Afro-Colombian patients who had no recent contact with Africa. The presence of HBV/E in this community as a monophyletic group suggests that it was a result of a recent introduction by some Afro-descendent contact or, alternatively, that the virus came with slaves brought to Colombia. By using sequences with sampling dates, we estimated the substitution rate to be about 3.2x10(-4) substitutions per site per year, which resulted in a time to the most recent common ancestor (TMRCA) of 29 years. In parallel, we also estimated the TMRCA for HBV/E by using two previously estimated substitution rates (7.7x10(-4) and 1.5x10(-5) substitutions per site per year). The TMRCA was around 35 years under the higher rate and 1500 years under the slower rate. In sum, this work reports for the first time the presence of an exclusively African HBV genotype circulating in South America. We also discuss the time of the entry of this virus into America based on different substitution rates estimated for HBV.

Dynamics of Hepatitis D (delta) virus genotype 3 in the Amazon region of South America

Hepatitis delta virus (HDV) is widely distributed and associated with fulminant hepatitis epidemics in areas with high prevalence of HBV. Several studies performed in the 1980s showed data on HDV infection in South America, but there are no studies on the viral dynamics of this virus. The aim of this study was to conduct an evolutionary analysis of hepatitis delta genotype 3 (HDV/3) prevalent in South America: estimate its nucleotide substitution rate, determine the time of most recent ancestor (TMRCA) and characterize the epidemic history and evolutionary dynamics. Furthermore, we characterized the presence of HBV/HDV infection in seven samples collected from patients who died due to fulminant hepatitis from Amazon region in Colombia and included them in the evolutionary analysis. This is the first study reporting HBV and HDV sequences from the Amazon region of Colombia. Of the seven Colombian patients, five were positive for HBV-DNA and HDV-RNA. Of them, two samples were successfully sequenced for HBV (subgenotypes F3 and Fib) and the five samples HDV positive were classified as HDV/3. By using all HDV/3 available reference sequences with sampling dates (n = 36), we estimated the HDV/3 substitution rate in 1.07 x 10(-3) substitutions per site per year (s/s/y), which resulted in a time to the most recent common ancestor (TMRCA) of 85 years. Also, it was determined that HDV/3 spread exponentially from early 1950s to the 1970s in South America. This work discusses for the first time the viral dynamics for the HDV/3 circulating in South America. We suggest that the measures implemented to control HBV transmission resulted in the control of HDV/3 spreading in South America, especially after the important raise in this infection associated with a huge mortality during the 1950s up to the 1970s. The differences found among HDV/3 and the other HDV genotypes concerning its diversity raises the hypothesis of a different origin and/or a different transmission route. (C) 2011 Elsevier B.V. All rights reserved.

In vivo effects of chicken interferon-gamma during infection with Eimeria

Newly hatched chickens are highly susceptible to infection by opportunistic pathogens during the first 1 or 2 weeks of life, The use of cytokines as therapeutic agents has been studied in animal models as well as in immunosuppressed patients, This approach has become more feasible in livestock animals, in particular poultry, with the recent cloning of cytokine genes and the development of new technologies, such as live delivery vectors, We have recently cloned the gene for chicken interferon-gamma (Ch-IFN-gamma), Poly-HIS-tagged recombinant Ch-IFN-gamma was expressed in Escherichia coil, was purified by Ni chromatography, and was found to be stable at 4 degrees C and an ambient temperature for at least several months and Several weeks, respectively, Ch-IFN-gamma was capable of protecting chick fibroblasts from undergoing virus-mediated lysis, induced nitrite secretion from chicken macrophages in vitro, and enhanced MHC class II expression on macrophages, Administration of recombinant Ch-IFN-gamma to chickens resulted in enhanced weight gain over a 12-day period, Furthermore, the therapeutic potential of Ch-IFN-gamma was assessed using a coccidial challenge model, Birds were treated with Ch-IFN-gamma or a diluent control and then infected with Eimeria acervulina. Infected birds treated with Ch-IFN-gamma showed improved weight gain relative to noninfected birds, The ability of Ch-IFN-gamma to enhance weight gain in the face of coccidial infection makes it an excellent candidate as a therapeutic agent.

Factors associated with mortality in patients with bloodstream infection and pneumonia due to Stenotrophomonas maltophilia

Severe infections caused by Stenotrophomonas maltophilia are associated with high mortality, and strategies to improve the clinical outcome for infected patients are needed. A retrospective cohort study of patients with bloodstream infection (BSIs) and pneumonia caused by S. maltophilia was conducted. Multivariate analysis was performed to access factors associated with 14-day mortality. A total of 60 infections were identified. Among these, eight (13%) were pneumonias and 52 were BSIs; 33.3% were primary, 13% were central venous catheter (CVC)-related and 40% were secondary BSIs. Fifty-seven (85%) patients had received previous antimicrobial therapy; 88% had CVC, 57% mechanical ventilation and 75% were in the intensive care unit at the onset of infection. Malignancy (45%) was the most frequent underlying disease. The mean of the Acute Physiology and Chronic Health Evaluation II (APACHE II) scores was 17 and for the Sepsis-related Organ Failure Assessment (SOFA) score, it was 7 points. The overall and 14-day mortality were, respectively, 75% and 48%. Forty-seven (78%) patients were treated and, of these, 74% received trimethoprim-sulfamethoxazole. Independent risk factors associated with mortality were SOFA index > 6 points (0.005) and septic shock (0.03). The Kaplan-Meier estimations curves showed that patients with APACHE II score > 20 and SOFA score > 10 had a survival chance of, respectively, less than 8% and less than 10% (P <= 0.001) at 21 days after the first positive S. maltophilia culture. Our results suggest that the independent factors associated with outcome in patients with infection caused by S. maltophilia are septic shock and higher SOFA index.

Reprocessing and reuse of single-use medical devices used during hemodynamic procedures in Brazil: A widespread and largely overlooked problem

Background. Several medical devices used during hemodynamic procedures, particularly angiographic diagnostic and therapeutic cardiac catheters, are manufactured for single use only. However, reprocessing and reuse of these devices has been reported, to determine the frequency of reuse and reprocessing of single-use medical devices used during hemodynamic procedures in Brazil and to evaluate how reprocessing is performed. Design. National survey, conducted from December 1999 to July 2001. Methods. Most of the institutions affiliated with the Brazilian Society of Hemodynamic and Interventional Cardiology were surveyed by use of a questionnaire sent in the mail. Results. The questionnaire response rate was 50% (119 of 240 institutions). Of the 119 institutions that responded, 116 (97%) reported reuse of single-use devices used during hemodynamic procedures, and only 26 (22%) reported use of a standardized reprocessing protocol. Cleaning, flushing, rinsing, drying, sterilizing and packaging methods varied greatly and were mostly inadequate. Criteria for discarding reused devices varied widely. Of the 119 institutions that responded, 80 (67%) reported having a surveillance system for adverse events associated with the reuse of medical devices, although most of these institutions did not routinely review the data, and only 38 (32%) described a training program for the personnel who reprocessed single-use devices. Conclusions. The reuse of single-use devices used during hemodynamic procedures was very frequent in hospitals in Brazil. Basic guidance on how to reuse and reprocess single-use medical devices is urgently needed, because, despite the lack of studies to support reusing and reprocessing single-use medical devices, such devices are necessary in limited-resource areas in which these practices are current.

Prevalence of, and risk factors for Kaposi`s sarcoma-associated herpesvirus infection among blood donors in Brazil: A multi-center serosurvey

Kaposi`s sarcoma-associated herpesvirus (KSHV) is endemic in the Amazon and rare in southern regions of Brazil. However, geographical distribution and epidemiological correlates of infection in this large country are still poorly defined. To estimate the seroprevalence of, and risk factors for, KSHV infection in Brazil, a multi-center study was conducted among 3,493 first-time voluntary unpaid blood donors from Salvador, Sao Paulo and Manaus. Antibodies against KSHV were detected using a whole-virus ELISA validated prior to the serosurvey. Antibodies against the latency-associated nuclear antigen (LANA) were detected by immuno-fluorescence assay (IFA) among ELISA-positive sera and a random sample of ELISA-negative sera. Overall, seroprevalence of KSHV by whole-virus ELISA was 21.7% (95% confidence interval (Cl): 20-23.4%) in men and 31.7% (95% Cl: 29-34.3%) in women (P<0.0001). KSHV antibodies were detected by IFA-LANA in 3% (95% Cl: 2-4.3%) of 867 ELISA-positive samples and in none of 365 randomly selected ELISA-negative samples. In multivariate analysis, KSHV seroprevalence by whole-virus ELISA was independently associated with female sex (odds ratio [OR] = 1.6, 95% Cl: 1.4-1.9); residence in the Amazon (OR = 1.4, 95% Cl: 1.2-1.8; compared to Salvador); Caucasian ethnicity (OR = 1.3, 95% Cl: 1.1-1.6) and herpes simplex virus type 2 (HSV-2) infection (OR = 1.3, 95% Cl: 1.1-1.6). KSHV seroprevalence did not significantly increase with age, nor was it associated with self-reported sexual behavior. KSHV seroprevalence is high among Brazilian blood donors, particularly from the Amazon region. This study supports the co-existence of sexual and non-sexual routes of KSHV transmission in this population.

Controlling the clonal spread of Pseudomonas aeruginosa infection

To evaluate nosocomial infections due to imipenem-resistant and imipenem-susceptible Pseudomonas aeruginosa, a case-control study that included genotyping was performed. Hospitalization for more than 15 days was independently associated with infection with an imipenem-resistant organism. Sixty-seven percent of the imipenem-resistant isolates analyzed and 23% of the imipenem-susceptible isolates analyzed belonged to a single clone. Intervention led to a decrease in the number of infections due to imipenem-resistant and imipenem-susceptible P. aeruginosa.

Involvement of the central nervous system in patients with dengue virus infection

The findings of a neurological evaluation in 85 patients with confirmed, acute, dengue virus infection are described. Signs of central nervous system involvement were present in IS patients (21.2%). The most frequent neurological symptom was mental confusion. The frequency of neurological involvement did not differ between patients with primary and secondary dengue infection, and the prevalence of central nervous system involvement in dengue fever and dengue hemorrhagic fever also did not differ significantly. The presence of CNS involvement did not influence the prognosis of dengue infection. Dengue viral CSF RNA was found in 7 of 13 patients submitted to a spinal tap, the CSF viral load being less than 1000 copies/ml. PCR was negative in serum samples obtained from three patients on the same day as the CSF samples, suggesting that the dengue virus actively enters the CNS and that the presence of the virus in the CNS does not result from passive crossing of the blood-brain barrier. (C) 2007 Elsevier B.V. All rights reserved.