Arterial properties in relation to genetic variations in the adducin subunits in a white population.

BACKGROUND: Adducin is a membrane skeleton protein, which consists of either alpha- and beta- or alpha- and gamma-subunits. We investigated whether arterial characteristics might be related to the genes encoding ADD1 (Gly460Trp-rs4961), ADD2 (C1797T-rs4984), and ADD3 (IVS11+386A>G-rs3731566). METHODS: We randomly recruited 1,126 Flemish subjects (mean age, 43.8 years; 50.3% women). Using a wall-tracking ultrasound system, we measured the properties of the carotid, femoral, and brachial arteries. We studied multivariate-adjusted phenotype-genotype associations, using a population- and family-based approach. RESULTS: In single-gene analyses, brachial diameter was 0.15 mm (P = 0.0022) larger, and brachial distensibility and cross-sectional compliance were 1.55 x 10(-3)/kPa (P = 0.013) and 0.017 mm(2)/kPa (P = 0.0029) lower in ADD3 AA than ADD3 GG homozygotes with an additive effect of the G allele. In multiple-gene analyses, the association of brachial diameter and distensibility with the ADD3 G allele occurred only in ADD1 GlyGly homozygotes. Otherwise, the associations between the arterial phenotypes in the three vascular beds and the ADD1 or ADD2 polymorphisms were not significant. In family-based analyses, the multivariate-adjusted heritability was 0.52, 0.38, and 0.30 for brachial diameter, distensibility, and cross-sectional compliance, respectively (P < 0.001). There was no evidence for population stratification (0.07 < or = P < or = 0.96). Transmission of the mutated ADD3 G allele was associated with smaller brachial diameter in 342 informative offspring (-0.12 +/- 0.04 mm; P = 0.0085) and in 209 offspring, who were ADD1 GlyGly homozygotes (-0.14 +/- 0.06 mm; P = 0.018). CONCLUSIONS: In ADD1 GlyGly homozygotes, the properties of the brachial artery are related to the ADD3 (A386G) polymorphism, but the underlying mechanism needs further clarification.

Elevated serum f erritin is an independent predictor of severe liver fibrosis, steatosis, and treatment failure in chronic hepatitis C

Background: Infection with the hepatitis C virus (HCV) i s associatedwith hepatic iron accumulation. We performed a comprehensive analysisof serum ferritin levels and of their genetic determinants in thepathogenesis and treatment of patients with chronic hepatitis C enrolledin the Swiss Hepatitis C Cohort Study (SCCS).Methods: Serum ferritin levels at baseline o f therapy with p egylatedinterferon-α ( PEG-IFN-α) and ribavirin or b efore liver biopsy werecorrelated with clinical features of c hronic HCV infection, includingnecroinflammatory activity (N=970), fibrosis (N=980), steatosis (N=886)and response to treatment (N=876). The association b etween highferritin levels (> median) and the endpoints w as assessed b y logisticregression. In addition, a candidate gene analysis as well as a genomewideassociation study (GWAS) of serum ferritin levels were performed.Results: S erum ferritin > sex-specific median was one of the strongestpre-treatment predictors of failure to achieve SVR (P<0.0001, OR=0.46,95% CI=0.34-0.60). This association remained highly significant in amultivariate analysis (P=0.0001, OR=0.32, 95% CI=0.18-0.57), with anodds ratio c omparable to that of IL28B g enotype, and persisted afteradjustment for duration of infection. Additional independent predictors ofnonresponse were viral load, HCV genotype, presence of diabetes, andliver fibrosis stage. Higher serum ferritin levels were also independentlyassociated with severe liver fibrosis (P<0.0001, OR=2.67, 95% CI=1.66-4.28) a nd steatosis (P=0.0034, OR=2.34, 95% CI=1.33-4.12), but n otwith necroinflammatory a ctivity (P=0.3). No significant g eneticdeterminants of serum ferritin levels were identified.Conclusions: Elevated serum ferritin levels are associated withadvanced liver fibrosis, hepatic steatosis, and poor r esponse to IFN-α-based therapy in c hronic hepatitis C, i ndependently from IL28Bgenotype.

Hepatitis C virus genotypes in blood donors from the Federal District, Central Brazil

The objective of this study was to characterize hepatitis C virus (HCV) genotypes in blood donors from the Federal District, Central Brazil, and to compare HCV screening by serological assays and reverse transcriptase polymerase chain reaction (RT-PCR). Plasma samples from 57 individuals with reactive or indeterminate results in serological anti-HCV screening assays (ELISA or EIA) were tested for HCV RNA by RT-PCR. The results from a confirmatory LIA serological assay were also evaluated. The 5' non-coding region of the HCV genome was amplified from 41 PCR positive samples (71.9%), which were further characterized by nucleotide sequencing analysis. Of these, 60.9% were of HCV genotype 1 and 39.1% of genotype 3.

Germline mutations in retinoma patients: relevance to low-penetrance and low-expressivity molecular basis.

PURPOSE: To study phenotype-genotype correlation in patients who have retinoma, which is a benign tumor resembling the post irradiation regression pattern of retinoblastoma (RB). METHODS: We selected patients who had retinoma and positive family history for RB and patients who had retinoma in one eye and either retinoma or RB in the other eye. The study included 22 patients with available DNA: 18 from 11 families and four sporadic cases. DNA was extracted from peripheral blood leukocytes. The RB1 gene was screened by DHPLC and direct sequencing of the promoter and all the exons. RESULTS: We identified 17 occurrences of 11 distinct germline mutations in two sporadic and in 15 familial cases (nine families). The 11 identified mutations were located in exons 1, 10,11,13,14, and 19 to 23. Four of the identified mutations were not previously reported, including g.64407delT, g.153236A>T, g.156743delTCTG, and g.162078delA. Eight out the 11 mutations were truncating and three were nontruncating (missense). There was no correlation between the type of mutation and the number of tumor foci per eye (RB or retinomas). Highly heterogeneous intrafamilial expressivity was observed. CONCLUSIONS: To our knowledge, this study is the largest series of mutations of consecutive retinoma patients. The present data suggest that the type of inherited mutations underlying retinoma is undistinguishable from RB related ones, i.e., largely dominated by truncating mutants. This finding is in contrast with the RB1 genotypic spectrum of mutations associated with low-penetrance RB, i.e., nontruncating mutants. The molecular mechanism underlying low-penetrance and attenuated expressivity (retinomas) appeared to be distinct.

Biomphalaria tenagophila: dominant character of the resistance to Schistosoma mansoni in descendants of crossbreedings between resistant (Taim, RS) and susceptible (Joinville, SC) strains

The aim of the present work was to study parasitological, molecular, and genetic aspects in descendants of crossbreedings between a totally resistant Biomphalaria tenagophila strain (Taim, RS) and another one highly susceptible (Joinville, SC) to Schistosoma mansoni. Descendants F1 and F2 were submitted to S. mansoni infection (LE strain). The susceptibility rates for individuals from Group F1 were 0 to 0.6%, and from Group F2 was 7.2%. The susceptible individuals from Group F2 discharged a lower number of cercariae, when compared with the susceptible parental group, and in 2 out of 9 positive snails the cercarial elimination was discontinued. In order to identify genetic markers associated with resistance the genotype of parental snails and their offspring F1 and F2 were analyzed by means of the randomly amplified polymorphic DNA method. Nevertheless, it was not possible to detect any marker associated to resistance, but the results showed that in the mentioned species the resistance character is determined by two dominant genes.

Escherichia coli variants in periprosthetic joint infection: diagnostic challenges with sessile bacteria and sonication.

The diagnostic yield of prosthetic joint-associated infection is hampered by the phenotypic change of bacteria into a sessile and resistant form, also called biofilm. With sonication, adherent bacteria can be dislodged from the prosthesis. Species identification may be difficult because of their variations in phenotypic appearance and biochemical reaction. We have studied the phenotypic, genotypic, and biochemical properties of Escherichia coli variants isolated from a periprosthetic joint infection. The strains were collected from synovial fluid, periprosthetic tissue, and fluid from the explanted and sonicated prosthesis. Isolates from synovial fluid revealed a normal phenotype, whereas a few variants from periprosthetic tissue and all isolates from sonication fluid showed different morphological features (including small-colony variants). All isolates from sonication fluid were beta-galactosidase negative and nonmotile; most were indole negative. Because of further variations in biochemical properties, species identification was false or not possible in 50% of the isolates included in this study. In contrast to normal phenotypes, variants were resistant to aminoglycosides. Typing of the isolates using pulsed-field gel electrophoresis yielded nonidentical banding patterns, but all strains were assigned to the same clonal origin when compared with 207 unrelated E. coli isolates. The bacteria were repeatedly passaged on culture media and reanalyzed. Thereafter, most variants reverted to normal phenotype and regained their motility and certain biochemical properties. In addition, some variants displayed aminoglycoside susceptibility after reversion. Sonication of an explanted prosthesis allows insight into the lifestyle of bacteria in biofilms. Since sonication fluid also reveals dislodged sessile forms, species identification of such variants may be misleading.

Detection of hepatitis C virus RNA by in situ hybridization in paraformaldehyde fixed biopsies

Fourteen hepatitis C virus (HCV) chronically infected patients were submitted to routine liver biopsy for histological evaluation. Liver samples were assayed to HCV-RNA by in situ hybridization, using digoxigenin labeled probe. HCV genotypes were found to be predominantly type 1 (71.4%), followed by genotype 3 (21.4%), and genotype 2 (7.2%). Alanine-aminotransferase levels were raised in 10 patients. The histopathological scores were minimal (21.4%), mild (57.2%), and moderate (21.4%). Viral RNA was detected in liver cells from nine patients (64.3%). ISH method provides localization and poor confirmation of HCV RNA in the liver tissue of HCV chronic patients.

Prevalence and risk factors of hepatitis C virus infection in hemodialysis patients from one center in Recife, Brazil

A hemodialysis population from a dialysis unit in the city of Recife, Northeastern Brazil, was screened to assess the prevalence of hepatitis C virus (HCV) infection and to investigate the associated risk factors. Hemodialysis patients (n = 250) were interviewed and serum samples tested for anti-HCV antibodies by enzyme-linked immunosorbent assay (ELISA). All samples were also tested for HCV RNA by reverse transcriptase nested polymerase chain reaction (RT-nested-PCR). Out of 250 patients, 21 (8.4%) were found to be seropositive by ELISA, and 19 (7.6%) patients were HCV RNA positive. HCV viraemia was present in 90.5% of the anti-HCV positive patients. The predominant genotype was HCV 1a (8/19), followed by 3a (7/19), and 1b (4/19). None of the anti-HCV negative patients were shown to be viraemic by the PCR. Univariate analysis of risk factors showed that time spent on hemodialysis, the number of blood transfusions and a blood transfusion before November 1993 were associated with HCV positivity. However, multivariate analysis revealed that blood transfusions before November 1993 were significantly associated with HCV infection in this population. Low prevalence levels were encountered in this center, however prospective studies are necessary to confirm these findings.

Marked hemiatrophy in carriers of Duchenne muscular dystrophy.

OBJECTIVE: To describe the clinical and molecular genetic findings in 2 carriers of Duchenne muscular dystrophy (DMD) who exhibited marked hemiatrophy. Duchenne muscular dystrophy is an X-linked disorder in which affected male patients harbor mutations in the dystrophin gene. Female patients with heterozygous mutations may be manifesting carriers. DESIGN: Case study. SETTING: Neurology clinic. PATIENTS: Two manifesting carriers of DMD. INTERVENTIONS: Clinical and radiologic examinations along with histologic and molecular investigations. RESULTS: Both patients had marked right-sided hemiatrophy on examination with radiologic evidence of muscle atrophy and fatty replacement on the affected side. In each case, histologic analysis revealed a reduction in dystrophin staining on the right side. Genetic analysis of the dystrophin gene revealed a tandem exonic duplication in patient 1 and a multiexonic deletion in patient 2 with no further point mutations identified on the other chromosome. CONCLUSIONS: Marked hemiatrophy can occur in DMD manifesting carriers. This is likely to result from a combination of skewed X-inactivation and somatic mosaicism.

Prevalence and genetic diversity of astroviruses in children with and without diarrhea in São Luís, Maranhão, Brazil

Human astroviruses (HAstV) have been increasingly identified as important etiological agents of acute gastroenteritis in children up to five years old. The aim of this study was to determine the prevalence and genotype diversity of HAstV in children with symptomatic and asymptomatic infections in São Luís, Maranhão, Brazil. From June 1997 to July 1999 a total of 183 fecal samples 84 from symptomatic and 99 from asymptomatic children were tested by enzyme immunoassay for HAstV. Prevalence rates were found to be 11 and 3% for symptomatic and asymptomatic children, respectively. Reverse transcription-polymerase chain reaction (RT-PCR) was carried out in 46 specimens (26 symptomatic and 20 asymptomatic) including the 12 samples that were positive by enzyme immunoassay (EIA). The overall positivity yielded by both methods was 8% (15/184); of these, 11% (9/84) for symptomatic and 5% (5/99) for those without symptoms or signs. Sequence analysis of amplicons revealed that HAstV-1 genotype was the most prevalent, accounting for 60% of isolates. Genotypes 2, 3, 4, and 5 were also detected, as one single isolate (10%) for each type. Variations in the sequences were observed when Brazilian isolates were compared to prototype strains identified in the United Kingdom. No seasonal pattern of occurrence was observed during these two years of study, and peak detection rate was observed in children aged between 3 and 6 months in the symptomatic group, and between 18 and 24 months in the controls.

Clinical and pathological importance of vacA allele heterogeneity and cagA status in peptic ulcer disease in patients from North Brazil

We have examined the prevalence of gene cagA and vacA alleles in 129 patients, 69 with gastritis and 60 with peptic ulcer diseases from North Brazil and their relation with histopathological data. vacA and cagA genotype were determined by polymerase chain reaction. Hematoxylin-eosin staining was used for histological diagnosis. 96.6% of the patients were colonized by Helicobacter pylori strains harboring single vacA genotype (nont-mixed infection). Among them, 11.8% had subtype s1a, 67.8% had subtype s1b, and 17% subtype s2. In regard to the middle region analysis, m1 alleles were found in 75.4% and m2 in 21.2% of patients. The cagA gene was detected in 78% patients infected with H. pylori and was associated with the s1-m1 vacA genotype. The H. pylori strains, vacA s1b m1/cagA-positive, were associated with increased risk of peptic ulcer disease and higher amounts of lymphocytic and neutrophilic infiltrates and the presence of intestinal metaplasia. These findings show that cagA and vacA genotyping may have clinical relevance in Brazil.

Serum uric acid and adiposity: deciphering causality using a bidirectional Mendelian randomization approach.

Although the relationship between serum uric acid (SUA) and adiposity is well established, the direction of the causality is still unclear in the presence of conflicting evidences. We used a bidirectional Mendelian randomization approach to explore the nature and direction of causality between SUA and adiposity in a population-based study of Caucasians aged 35 to 75 years. We used, as instrumental variables, rs6855911 within the SUA gene SLC2A9 in one direction, and combinations of SNPs within the adiposity genes FTO, MC4R and TMEM18 in the other direction. Adiposity markers included weight, body mass index, waist circumference and fat mass. We applied a two-stage least squares regression: a regression of SUA/adiposity markers on our instruments in the first stage and a regression of the response of interest on the fitted values from the first stage regression in the second stage. SUA explained by the SLC2A9 instrument was not associated to fat mass (regression coefficient [95% confidence interval]: 0.05 [-0.10, 0.19] for fat mass) contrasting with the ordinary least square estimate (0.37 [0.34, 0.40]). By contrast, fat mass explained by genetic variants of the FTO, MC4R and TMEM18 genes was positively and significantly associated to SUA (0.31 [0.01, 0.62]), similar to the ordinary least square estimate (0.27 [0.25, 0.29]). Results were similar for the other adiposity markers. Using a bidirectional Mendelian randomization approach in adult Caucasians, our findings suggest that elevated SUA is a consequence rather than a cause of adiposity.

Detection and molecular characterization of group A rotavirus from hospitalized children in Rio de Janeiro, Brazil, 2004

Rotavirus is a major cause of infantile acute diarrhea, causing about 440,000 deaths per year, mainly in developing countries. The World Health Organization has been recommending the assessment of rotavirus burden and strain characterization as part of the strategies of immunization programs against this pathogen. In this context, a prospective study was made on a sample of 134 children with acute diarrhea and severe dehydration admitted to venous fluid therapy in two state hospitals in Rio de Janeiro, Brazil, from February to September 2004. Rotavirus where detected by polyacrylamide gel electrophoresis (PAGE) and by an enzyme-linked immunoassay to rotavirus and adenovirus (EIARA) in 48% of the children. Positive samples for group A rotavirus (n = 65) were analyzed by reverse transcription/heminested multiplex polymerase chain reaction to determine the frequency of G and [P] genotypes and, from these, 64 samples could be typed. The most frequent G genotype was G1 (58%) followed by G9 (40%). One mixed infection (G1/G9) was detected. The only [P] genotype identified was [8]. In order to estimate the rotavirus infection frequency in children who acquired diarrhea as hospital infection in those hospitals, we studied 24 patients, detecting the pathogen in 41% of them. This data suggest that genotype G9 is an important genotype in Rio de Janeiro, with implications to the future strategies of vaccination against rotavirus, reinforcing the need of continuous monitoring of circulating strains of the pathogen, in a surveillance context.

Molecular characterization of human Trypanosoma cruzi isolates from endemic areas in Panama

The present work provides information on Trypanosoma cruzi genotype circulating in endemic areas of Chagas disease in Panama. A total of 26 crude stocks of T. cruzi, isolated from the blood of persons with different clinical profiles of Chagas disease were collected and crio-conserved until used. Most of the stocks had been characterized by means of isoenzyme electrophoresis on cellulose acetate membranes. The clinical profiles of infected persons included 9 (34.6%) asymptomatic and 17 acute (65.4%) including 5 (19.2%) fatal cases, 2 under 5 years old and 3 adults. A multiplex-PCR assay based on the amplification of the non-transcribed spacer of the mini-exon gene was performed. All stocks of T. cruzi included in the study were found to correspond to Tc I group. This result supports the predominance of T. cruzi-I in the transmission cycles affecting the human population in the Republic of Panama.

Hepatitis B virus infection profile in hemodialysis patients in Central Brazil: prevalence, risk factors, and genotypes

Hemodialysis patients are at high risk for hepatitis B virus (HBV) infection. A survey was conducted in the hemodialysis population of the state of Goiás, Central Brazil, aiming to assess the prevalence of HBV infection, to analyse associated risk factors, and also to investigate HBV genotypes distribution. A total of 1095 patients were interviewed in 15 dialysis units. Serum samples were screened for HBV serological markers by enzyme-linked immunosorbent assay. Hepatitis B surface antigen (HBsAg) positive samples were tested for HBV DNA by polymerase chain reaction and genotyped by restriction fragment length polymorphism. Global HBV infection prevalence was 29.8% (95% CI: 27.1-32.5). Multivariate analysis of risk factors showed that male gender, length of time on hemodialysis, and blood transfusion before 1993 were associated with HBV positivity. HBV DNA was detected in 65.4% (17/26) of the HBsAg-positive samples. Thirteen of 17 HBV DNA positive samples were genotyped. Genotype D (61.5%) was predominant, followed by A (30.8%), while genotype F was detected in only one (7.7%) sample.