Human pegivirus 1 in Cabo Verde: prevalence and genotypic distribution among HIV-infected individuals.

Human pegivirus 1 (HPgV-1) belongs to the genus Pegivirus, family Flaviviridae, and until now has been considered a non-pathogenic agent, despite being considered a risk factor for non-Hodgkin lymphoma. However, a beneficial impact of HPgV-1 on HIV disease progression has been extensively reported. Given the high prevalence of HIV in sub-Saharan Africa and the scarcity of epidemiological data for many countries of West Africa, we conducted the first study of HPgV-1 in HIV-infected individuals from Cabo Verde. To obtain new data regarding prevalence and genetic diversity of HPgV-1 in Africa, serum samples from 102 HIV-infected Cabo Verdeans were tested for the presence of viral RNA, and the circulating genotypes were identified by sequencing of the 5' untranslated region. HPgV-1 RNA was detected in 19.6% (20/102) of the samples. In 72.2% (13/18) of the samples, the virus was identified as genotype 2 (11/13 subtype 2a and 2/13 subtype 2b), and in 27.8% (5/18), it was identified as genotype 1. The estimated substitution rate of HPgV-1 genotype 2 was 5.76 × 10-4, and Bayesian analysis indicated the existence of inner clusters within subtypes 2a and 2b. The prevalence of HPgV-1 viremia in Cabo Verde agrees with that reported previously in Africa. Genotypes 1 and 2 cocirculate, with genotype 2 being more common, and HIV/HPgV-1 coinfection was not associated with higher CD4 T cell counts in the studied population. This finding contributes for the expansion of the pegivirus research agenda in African countries.

Human pegivirus-1 infection in kidney transplant recipients: A single-center experience.

Kidney transplantation is the treatment of choice for patients with end-stage renal disease. In the posttransplant period, the induced immunosuppression leads to an increased risk of developing infectious diseases, a leading cause of death after kidney transplantation. Human pegivirus-1 (HPgV-1) is considered a nonpathogenic human virus and is highly frequent in individuals parenterally exposed, however, its impact on kidney transplantation outcome is poorly understood. Given the scarcity of epidemiological data for this infection on organ recipients in Brazil, we conducted a study in a single center for kidney transplantation in Rio de Janeiro, aiming to determine HPgV-1 prevalence and genotypic distribution. Serum samples from 61 renal recipients, followed up for the first year after transplantation, were evaluated for viral RNA and genotypes were determined by sequencing of the 5'-untranslated region. HPgV-1 RNA was detected in 36.1% (22/61) of patients. Genotype 2 was the most commonly found (80.9%), followed by genotypes 3 (9.5%), 1, and 5, in 4.8% each. Statistical comparisons did not reveal any significant impact of HPgV-1 in patient outcome. Further epidemiologic studies are needed to understand if immunosuppression may interfere in HPgV-1 persistence rates and if viremia might impact graft dysfunction rates in kidney recipients.

Molecular and serological characterization of occult hepatitis B among blood donors in Maputo, Mozambique.

BACKGROUND: Occult hepatitis B virus (HBV) - characterized by the absence of detectable HBsAg in the presence of HBV DNA - represents a potential threat for blood safety. OBJECTIVES: This study was conducted with the aim to investigate the serological and molecular characterization of occult HBV infection (OBI) among blood donors in Mozambique. METHODS: 1,502 blood donors were tested for HBsAg. All HBsAg-negative individuals were tested for HBV DNA. Antibodies against HBV core, surface and HBe antigen (anti-HBc, anti-HBs, HBeAg) were measured in HBV DNA positive individuals. FINDINGS: 1435 serum samples were HBsAg negative and 16 positive for HBV DNA, 14 confirmed to have OBI, corresponding to a frequency of 0.98%. Of the 14 OBI infections identified, 13/14 (92.8%) were positive for anti-HBc, 4/14 (28.5%) for anti-HBs, and no samples were reactive for HBeAg. Of the 14 OBI cases, nine samples (64.2%) were sequenced for the S/P region. Eight samples (88.9%) belonged to genotype A1 and one (11.1%) to genotype E. One escape mutation (T123A) associated with OBI and various amino acid substitutions for genotype A1 and E were observed. MAIN CONCLUSIONS: Our results show the importance of using nucleic acid amplification test to detect occult hepatitis B infection in blood donors in Mozambique.

The Effect of Nanosystems on ATP-Binding Cassette Transporters: Understanding the Influence of Nanosystems on Multidrug Resistance Protein-1 and P-glycoprotein.

The cancer multidrug resistance is involved in the failure of several treatments during cancer treatment. It is a phenomenon that has been receiving great attention in the last years due to the sheer amount of mechanisms discovered and involved in the process of resistance which hinders the effectiveness of many anti-cancer drugs. Among the mechanisms involved in the multidrug resistance, the participation of ATP-binding cassette (ABC) transporters is the main one. The ABC transporters are a group of plasma membrane and intracellular organelle proteins involved in the process of externalization of substrates from cells, which are expressed in cancer. They are involved in the clearance of intracellular metabolites as ions, hormones, lipids and other small molecules from the cell, affecting directly and indirectly drug absorption, distribution, metabolism and excretion. Other mechanisms responsible for resistance are the signaling pathways and the anti- and pro-apoptotic proteins involved in cell death by apoptosis. In this study we evaluated the influence of three nanosystem (Graphene Quantum Dots (GQDs), mesoporous silica (MSN) and poly-lactic nanoparticles (PLA)) in the main mechanism related to the cancer multidrug resistance such as the Multidrug Resistance Protein-1 and P-glycoprotein. We also evaluated this influence in a group of proteins involved in the apoptosis-related resistance including cIAP-1, XIAP, Bcl-2, BAK and Survivin proteins. Last, colonogenic and MTT (3-(4,5-dimethylthiazol-2-yl)- 2,5-diphenyltetrazolium bromide) assays have also been performed. The results showed, regardless of the concentration used, GQDs, MSN and PLA were not cytotoxic to MDA-MB-231 cells and showed no impairment in the colony formation capacity. In addition, it has been observed that P-gp membrane expression was not significantly altered by any of the three nanomaterials. The results suggest that GQDs nanoparticles would be suitable for the delivery of other multidrug resistance protein 1 (MRP1) substrate drugs that bind to the transporter at the same binding pocket, while MSN can strongly inhibit doxorubicin efflux by MRP1. On the other hand, PLA showed moderate inhibition of doxorubicin efflux by MRP1 suggesting that this nanomaterial can also be useful to treat MDR (Multidrug resistance) due to MRP1 overexpression.

Hepatitis D infection in Brazil: Prevalence and geographical distribution of anti-Delta antibody.

In Brazil, the Amazon Basin is endemic for hepatitis D virus (HDV) infection; however, studies in other regions of the country are scarce. This study aims to map the seroepidemiological situation of anti-Delta antibodies in chronic hepatitis B carriers in all five Brazilian geographic regions. Serum samples from 1240 HBsAg positive individuals (55.4% men; mean age 43.1 ± 13.4 years) from 24 of 26 Brazilian states were tested for the presence of anti-Delta antibodies using a commercial immunoassay. Anti-Delta antibodies were detected in 40 samples (3.2%; 52.5% female; mean age of 38.1 ± 13.8 years). Age less than 20 years was significantly associated with anti-HDV positivity (P < 0.001). The distribution of anti-Delta differed markedly in the diverse regions of the country. The highest prevalence of anti-HDV was found in the North (8.5%; P < 0.001), followed by Central West (2.5%), Southeast (1.7%), Northeast (0.8%), and South (0.0%). Anti-Delta antibodies were detected in 12 states, but more than 60% of the positive cases were observed in two states, Amazonas and Acre, located in the western portion of the Amazon region. The overall HDV prevalence of 3.2% emphasizes that HDV is far from being a disease under control in Brazil. Despite the low HDV prevalence in non-endemic regions, this infection persists as a major concern in two states (Acre and Amazonas) in the north of the country, indicating that a continuous epidemiological surveillance program should be implemented in all Brazilian regions.

Nationwide overview of the distribution of hepatitis B virus genotypes in Brazil: a 1000-sample multicentre study.

The influence of hepatitis B virus (HBV) genotypes in the natural history of the disease and its response to antiviral treatment have been addressed in many studies. In Brazil, studies on HBV genotype circulation have been restricted to specific population groups and states. Here, we have conducted a nationwide multicentre study with an unprecedented sample size representing all Brazilian regions in an effort to better understand the viral variants of HBV circulating among chronic carriers. Seven HBV genotypes were found circulating in Brazil. Overall, HBV/A was the most prevalent, identified in 589 (58.7 %) samples, followed by HBV/D (23.4 %) and HBV/F (11.3 %). Genotypes E, G, C and B were found in a minor proportion. The distribution of the genotypes differed markedly from the north to the south of the country. While HBV/A was the most prevalent in the North (71.6 %) and Northeast (65.0 %) regions, HBV/D was found in 78.9 % of the specimens analysed in the South region. HBV/F was the second most prevalent genotype in the Northeast region (23.5 %). It was detected in low proportions (7 to 10 %) in the North, Central-West and Southeast regions, and in only one sample in the South region. HBV/E was detected in all regions except in the South, while monoinfection with HBV/G was found countrywide, with the exception of Central-West states. Our sampling covered 24 of the 26 Brazilian states and the Federal District and is the first report of genotype distribution in seven states. This nationwide study provides the most complete overview of HBV genotype distribution in Brazil to date and reflects the origin and plurality of the Brazilian population.

Complete genome sequence of a hepatitis B virus isolate of genotype D2, subtype adrq+, from Brazil.

Hepatitis B virus (HBV) has been classified into 10 distinct serological subtypes of the surface antigen (HBsAg) that can be predicted by sequencing of the corresponding S gene. HBV genotype D usually displays determinants of subtypes ayw2 or ayw3. On the other hand, subtype adrq+ has been found exclusively in association with genotype C. Here, we describe the first HBV genome (isolate BR32) belonging to genotype D with the serological subtype adrq+. This isolate had a genome length of 3,062 nucleotides (nt), and no recombination events were observed in the BR32 genome that could explain the occurrence of the subtype adr in a genotype D isolate. Analysis of the quasispecies population revealed that 28 out of 30 clones (93%) were of subtype adrq+, while the subtypes of the two remaining could not be determined, since they contained an S residue (instead of K or R) at position 122 of HBsAg. These results will contribute to further epidemiological and evolutionary studies of HBV.

Detection and molecular characterisation of a diagnosis escape variant associated with occult hepatitis B virus in Brazil.

BACKGROUND: Many studies have identified mutations in the hepatitis B surface antigen (HBsAg) as important factors limiting the ability of commercial serological assays to detect this viral antigen. However, an association between mutations in the HBsAg gene and the occurrence of occult HBV infection (OBI) in patients has not been established. OBJECTIVES: To detect hepatitis B virus (HBV) DNA in patients with anti-HBc as a unique serological marker, a previously published, cost-effective TaqMan-based real-time polymerase chain reaction (PCR) test with minor groove binding probes was adapted for use in this study. The current study also aimed to investigate HBsAg mutations and genotypes of HBV in OBI at the Viral Hepatitis Ambulatory Clinic in Rio de Janeiro to determine any possible association. METHODS: Intra-assay and inter-assay reproducibility were determined, and the mean coefficient of variation values obtained were 2.07 and 3.5, respectively. Probit analysis indicated that the 95% detection level was 25 IU/mL. The prevalence of OBI was investigated in 35 serum samples with an 'anti-HBc alone' profile from individuals who attended our clinic between 2011 and 2013. FINDINGS: HBV DNA was detected in only one sample, resulting in an OBI rate of 2.9%. Nucleotide sequencing of the pre-S/S region was performed to genotype and analyse mutations within the HBsAg gene of this HBV DNA. The HBV in the OBI case was classified as sub-genotype A1, and a sequence analysis of the small S gene revealed 12 mutations in the major hydrophilic region compared to the consensus A1 sequence. Most of these mutations occurred in amino acid residues that have been reported as clinically relevant because they have been implicated in vaccine escape and/or inability to detect HBsAg by commercial serological assays. MAIN CONCLUSIONS: Our study suggests the importance of specific HBsAg mutations, different from those in D, B, and C genotypes, in sub-genotype A1 HBV associated with OBI.

Full-genome sequences of hepatitis B virus subgenotype D3 isolates from the Brazilian Amazon Region.

The Brazilian Amazon Region is a highly endemic area for hepatitis B virus (HBV). However, little is known regarding the genetic variability of the strains circulating in this geographical region. Here, we describe the first full-length genomes of HBV isolated in the Brazilian Amazon Region; these genomes are also the first complete HBV subgenotype D3 genomes reported for Brazil. The genomes of the five Brazilian isolates were all 3,182 base pairs in length and the isolates were classified as belonging to subgenotype D3, subtypes ayw2 (n = 3) and ayw3 (n = 2). Phylogenetic analysis suggested that the Brazilian sequences are not likely to be closely related to European D3 sequences. Such results will contribute to further epidemiological and evolutionary studies of HBV.

Studies of genotoxicity and mutagenicity of nitroimidazoles: demystifying this critical relationship with the nitro group.

Nitroimidazoles exhibit high microbicidal activity, but mutagenic, genotoxic and cytotoxic properties have been attributed to the presence of the nitro group. However, we synthesised nitroimidazoles with activity against the trypomastigotes of Trypanosoma cruzi, but that were not genotoxic. Herein, nitroimidazoles (11-19) bearing different substituent groups were investigated for their potential induction of genotoxicity (comet assay) and mutagenicity (Salmonella/Microsome assay) and the correlations of these effects with their trypanocidal effect and with megazol were investigated. The compounds were designed to analyse the role played by the position of the nitro group in the imidazole nucleus (C-4 or C-5) and the presence of oxidisable groups at N-1 as an anion receptor group and the role of a methyl group at C-2. Nitroimidazoles bearing NO2 at C-4 and CH3 at C-2 were not genotoxic compared to those bearing NO 2 at C-5. However, when there was a CH3 at C-2, the position of the NO2 group had no influence on the genotoxic activity. Fluorinated compounds exhibited higher genotoxicity regardless of the presence of CH3 at C-2 or NO2 at C-4 or C-5. However, in compounds 11 (2-CH3; 4-NO2; N-CH2OHCH2Cl) and 12 (2-CH3; 4-NO2; N-CH2OHCH2F), the fluorine atom had no influence on genotoxicity. This study contributes to the future search for new and safer prototypes and provide.

Endecous apterus: a new species of cave cricket from northeast Brazil, with comments on the use of subterranean habitats by Luzarinae crickets (Orthoptera: Grylloidea: Phalangopsidae: Luzarinae).

In this study we describe the first apterous species of Endecous Saussure (1878), collected in two caves at Ituaçu, Bahia State, Brazil. In Brazil, Endecous is the most widespread cricket in hypogean environments and its species can colonize caves and inhabit the entrance and the aphotic zones; Endecous species can also be found in the litter, rock gullies, crevices, burrows, and any natural cavities. The use of subterranean habitat by Endecous crickets and its related genera are discussed.

Could Herpesviridae be the cause of severe acute hepatitis of unknown origin in children?

INTRODUCTION: Severe acute hepatitis (SAH) is defined by a severe inflammation of hepatocytes in the liver parenchyma which can lead to an acute liver failure, a clinical condition with high mortality rate that can be triggered by several factors but is usually associated to hepatotropic viruses' infection. In 2022, cases of children with severe acute hepatitis of unknown origin hospitalized in Glasgow, Scotland, were reported. Possible causes of this condition include, but are not limited to, undiagnosed viral (and non-viral) infections, autoimmune hepatitis, drug and/or chemical toxicity, mitochondrial chain respiratory and metabolic disorders. AREAS COVERED: Herpesviruses can cause severe acute hepatitis, but little is known about the role and the mechanisms of herpesviruses as a causative agent of this type of hepatitis. We review the role of herpesviruses as causative agent of SAH in children and other possible mechanisms involved in this disease. EXPERT OPINION: Differential diagnosis for herpesvirus in SAH should be implemented in all settings. Alternative fluids, such as saliva and dried blood, could be used in the diagnosis to overwhelm the availability of biological specimens at sufficient volume. In the future, genetic studies could also be added to increase the knowledge about severe acute hepatitis in children.

Genetic variability of hepatitis B virus in acute and in different phases of chronic infection in Brazil.

The selection pressure imposed by the host immune system impacts on hepatitis B virus (HBV) variability. This study evaluates HBV genetic diversity, nucleos(t)ide analogs resistance and HBsAg escape mutations in HBV patients under distinct selective pressures. One hundred and thirteen individuals in different phases of HBV infection were included: 13 HBeAg-positive chronic infection, 9 HBeAg-positive chronic hepatitis, 47 HBeAg-negative chronic infection (ENI), 29 HBeAg-negative chronic hepatitis (ENH) and 15 acute infected individuals. Samples were PCR amplified, sequenced and genetically analyzed for the overlapping POL/S genes. Most HBV carriers presented genotype A (84/113; 74.3%), subgenotype A1 (67/84; 79.7%), irrespective of group, followed by genotypes D (20/113; 17.7%), F (8/113; 7.1%) and E (1/113; 0.9%). Clinically relevant mutations in polymerase (tL180M/M204V) and in the Major Hydrophilic Region of HBsAg (sY100C, T118A/M, sM133T, sD144A and sG145R) were observed. Our findings, however, indicated that most polymorphic sites were located in the cytosolic loops (CYL1-2) and transmembrane domain 4 (TMD4) of HBsAg. Lower viral loads and higher HBV genetic diversity were observed in ENI and ENH groups (p < 0.001), suggesting that these groups are subjected to a higher selective pressure. Our results provide information on the molecular characteristics of HBV in a diverse clinical setting, and may guide future studies on the balance of HBV quasispecies at different stages of infection.

Phylogeography and evolutionary history of hepatitis B virus genotype F in Brazil.

BACKGROUND: Hepatitis B virus (HBV) genotype F (HBV/F) is considered to be indigenous to the Americas, but its emergence and spread in the continent remain unknown. Previously, only two HBV/F complete genome sequences from Brazil were available, limiting the contribution of Brazilian isolates to the phylogenetic studies of HBV/F. The present study was carried out to assess the proportion and geographic distributions of HBV/F subgenotypes in Brazil, to determine the full-length genomic sequences of HBV/F isolates from different Brazilian geographic regions, and to investigate the detailed evolutionary history and phylogeography of HBV/F in Brazil. METHODS: Complete HBV/F genomes isolated from 12 Brazilian patients, representing the HBV/F subgenotypes circulating in Brazil, were sequenced and analyzed together with sequences retrieved from GenBank, using the Bayesian coalescent and phylogeographic framework. RESULTS: Phylogenetic analysis using all Brazilian HBV/F S-gene sequences available in GenBank showed that HBV/F2a is found at higher frequencies countrywide and corresponds to all sequences isolated in the Brazilian Amazon Basin. In addition, the evolutionary analysis using complete genome sequences estimated an older median ancestral age for the Brazilian HBV/F2a compared to the Brazilian HBV/F1b and HBV/F4 subgenotypes, suggesting that HBV/F2a represents the original native HBV of Brazil. The phylogeographic patterns suggested a north-to-south flow of HBV/F2a from Venezuela to Brazil, whereas HBV/F1b and HBV/F4 strains appeared to have spread from Argentina to Brazil. CONCLUSIONS: This study suggests a plausible route of introduction of HBV/F subgenotypes in Brazil and demonstrates the usefulness of recently developed computational tools for investigating the evolutionary history of HBV.

Evaluation of genotoxic effects of new molecules with possible trypanocidal activity for Chagas disease treatment.

Chagas disease is responsible for a large number of human infections and many are also at risk of infection. There is no effective drug for Chagas disease treatment. The Institute of Pharmaceutical Technology at Fiocruz, Brazil, has designed three nitro analogs of the nitroimidazole-thiadiazole, megazol: two triazole analogs PTAL 05-02 and PAMT 09 and a pyrazole analog PTAL 04-09. A set of Salmonella enterica serovar Typhimurium strains were used in the bacterial reverse mutation test (Ames test) to determine the mutagenicity and cytotoxicity of megazol and its nitro analogs. Megazol presented positive mutagenic activity at very low concentration, either with or without metabolic activation S9 mix. The mutagenic response of the analogs was detected at higher concentration than the lowest megazol concentration to yield mutagenic activity showing that new advances can be made to develop new analogs. The micronucleus test with rat macrophage cells was used in the genotoxic evaluation. The analogs were capable of inducing micronucleus formation and showed cytotoxic effects. PTAL 04-09 structural modifications might be better suitable for the design of promising new drugs candidate for Chagas' disease treatment.

Bambuina bambui: a new genus and species of cave cricket from Brazil (Orthoptera: Grylloidea: Phalangopsidae: Luzarinae).

Bambuina bambui, um novo gênero e espécie de grilo falangopsídeo é descrito a partir de espécimes obtidos na Gruta do Centenário, uma caverna de quartzo localizada na Serra do Inficionado, um subconjunto de montanhas pertencentes ao complexo da Serra do Caraça no estado de Minas Gerais, Brasil.

Peulerneca ubaira gen. et sp. nov.: A new Lernecina cricket with white and hyaline forewings from the Brazilian Atlantic Forest (Phalangopsidae, Luzarinae, Lernecina).

Here we describe a new genus and species of cricket belonging to Lernecina from the Brazilian Atlantic Forest. It is presently known only from Ubaíra, State of Bahia, Brazil. The new genus is the only known member of this subtribe having males with a mostly white and hyaline dorsal field of the forewing (an additional genus with that condition is in the process of being described).

Circulation of HDV Genotypes in Brazil: Identification of a Putative Novel HDV-8 Subgenotype.

Hepatitis D virus (HDV) is classified into 8 genotypes (1 to 8) and several subgenotypes. In Brazil, HDV-3 and HDV-1 predominate; however, most of the diagnosis efforts and molecular studies are directed to the area of endemicity of the Amazon Basin. Here, we determined the molecular epidemiological profile of circulating HDV in Brazilian HBsAg-positive patients between 2013 and 2015 in areas of endemicity and non-areas of endemicity. From 38 anti-HDV-positive individuals, 13 (34.2%) had detectable HDV-RNA and 11 (28.9%) were successfully sequenced. Partial HDAg (~320 nt) sequencing followed by phylogenetic analysis with reference sequences resulted in the identification of HDV-3 (9/11; 81.8%), HDV-5 (1/11; 9.1%), and HDV-8 (1/11; 9.1%). Most HDV-3 samples (8/9; 88.9%) were found in the endemic North region, while one was found in Central-West Brazil, a non-area of endemicity. HDV-5 and 8, genotypes native from African countries, were found in São Paulo, a cosmopolitan city from Southeast Brazil with a high circulation of immigrants. Phylogenetic analysis of HDV-8 strains indicated that the sample determined in our study, along with previously reported sequences from Brazil, formed a highly supported monophyletic clade, likely representing a putative novel HDV-8 subgenotype. IMPORTANCE Considered a neglected pathogen until the last 2 decades, an increase in the availability of genetic data of hepatitis D virus (HDV) strains around the world has been noticed recently, resulting in the proposition of different classifications. Our study aimed to determine the molecular epidemiological profile of HDV isolates circulating in areas of endemicity and non-areas of endemicity in Brazil. Based on the analyzed fragment, HDV-8 sequences clustered out of the clades formed by subgenotypes 8a and 8b might suggest the identification of a novel subgenotype, putatively designated subgenotype 8c. Our findings demonstrate the importance of continuous epidemiological surveillance to map HDV spread pathways and the introduction of imported variants. It also reinforces that as the amount of HDV genomes generated and reported increases, we will have changes in viral classification and, consequently, in our understanding of the dynamics of variability of this viral agent.

Histopathological diagnosis in pediatric stomatology: A 43-year retrospective study of 1,480 cases from a Brazilian institution.

OBJECTIVES: the aim of this study was to analyze the prevalence of histopathological diagnoses in oral biopsied tissues obtained from a Brazilian pediatric population. METHODS: an analytical, cross-sectional retrospective study was performed with biopsy files of patients ≤14 years of age from a Brazilian oral pathology laboratory over a 43-year period. Data included sex, age, location, and diagnoses. The prevalence was calculated by means of relative frequency. Associations between sex, age groups and diagnoses were verified with Pearson's chi-square test. RESULTS: from 19,456 oral biopsies, 1480 (7.6%) were obtained from patients aged ≤14 years. Most children were 10-14 years of age (60.1%) and females (55.1%), with an overall M:F of 1:1.2. Children aged 0-9 years and males had a higher frequency of lesions of the oral mucosa, whilst the 10-14 year age group showed a higher frequency of cysts, odontogenic tumors, and salivary gland lesions. The latter was also significantly higher in females. Samples consisted mostly of soft tissue lesions (53%) obtained from the lower lip (30.7%). Intraosseous lesions showed a slight predilection for the mandible (21.2%). Salivary gland lesions (28.8%) was the most common diagnostic category, followed by reactive lesions (18.8%), and cysts (16.1%). Mucocele (33.5%), dentigerous cyst (6.7%), and fibrous hyperplasia (5.9%) were the top three histopathological diagnoses. Malignant lesions affected only 0.9% of this population. CONCLUSION: our results were similar to other retrospective studies. Due to the low frequency of oral biopsies in children, data on the prevalence of oral pathology in this population might aid in the clinical and histopathologic diagnoses.

Detection of mixed populations of wild-type and YMDD hepatitis B variants by pyrosequencing in acutely and chronically infected patients.

BACKGROUND: Lamivudine (LAM) is associated with the highest known rate of resistance mutations among nucleotide analogs used to treat chronic hepatitis B virus (HBV) infection. Despite this, LAM continues in widespread use, especially in combination therapies. The primary LAM resistance mutation (rtM204V/I) occurs in the YMDD motif of HBV polymerase. The aim of this study was to characterize Brazilian HBV isolates from acute and chronic cases by direct sequencing, and to identify HBV quasispecies in the YMDD motif using a pyrosequencing method capable of detecting single-nucleotide polymorphisms. HBV DNA from serum samples of 20 individuals with acute HBV infection and 44 with chronic infection undergoing antiviral therapies containing LAM were analyzed by direct sequencing and pyrosequencing methods. RESULTS: Phylogenic analyses of direct-sequenced isolates showed the expected genotypes (A, D and F) for the Brazilian population in both acute and chronic infections. However, within genotype A isolates, subgenotype A2 was more frequently detected in acute cases than in chronic cases (P = 0.012). As expected, none of the individuals with acute hepatitis B had LAM-resistant isolates as a dominant virus population, whether detected by direct sequencing or pyrosequencing. However, pyrosequencing analyses showed that 45% of isolates (9/20) had minor subpopulations (4-17%) of LAM-resistant isolates. Among chronic patients undergoing LAM treatment, YMDD mutants were frequently found as a dominant virus population. In cases where wild-type virus was the dominant population, subpopulations of YMDD variants were usually found, demonstrating the complexity of HBV quasispecies. CONCLUSIONS: YMDD variants were frequently detected as a minor population in acute HBV infection. The occurrence of pre-existing variants may lead to a high frequency of resistant mutants during antiviral therapy in the chronic phase. In chronic infection, detection of YMDD variants before virological or biochemical breakthrough might contribute to making better therapy choices and thus improving treatment outcome.