High Frequency of Lamivudine Resistance Mutations in Brazilian Patients Co-Infected With HIV and Hepatitis B

This study analyzed the genotype distribution and frequency of lamivudine (LAM) and tenofovir (TDF) resistance mutations in a group of patients co-infected with HIV and hepatitis B virus (HBV). A cross-sectional study of 847 patients with HIV was conducted. Patients provided blood samples for HBsAg detection. The load of HBV was determined using an ""in-house"" real-time polymerase chain reaction. HBV genotypes/subgenotypes, antiviral resistance, basal core promoter (BCP), and precore mutations were detected by DNA sequencing. Twenty-eight patients with co-infection were identified. The distribution of HBV genotypes among these patients was A (n = 9; 50%), D (n = 4; 22.2%), G (n = 3; 16.7%), and F (n = 2; 11.1%). Eighteen patients were treated with LAM and six patients were treated with LAM plus TDF. The length of exposure to LAM and TDF varied from 4 to 216 months. LAM resistance substitutions (rtL180M + rtM204V) were detected in 10 (50%) of the 20 patients with viremia. This pattern and an accompanying rtV173L mutation was found in four patients. Three patients with the triple polymerase substitution pattern (rtV173L+ rtL180M + rtM204V) had associated changes in the envelope gene (sE164D + sl195M). Mutations in the BCP region (A1762T, G1764A) and in the precore region (G1896A, G1899A) were also found. No putative TDF resistance substitution was detected. The data suggest that prolonged LAM use is associated with the emergence of particular changes in the HBV genome, including substitutions that may elicit a vaccine escape phenotype. No putative TDF resistance change was detected after prolonged use of TDF. J. Med. Virol. 82:1481-1488, 2010. (C) 2010 Wiley-Liss, Inc.

In vitro antifungal drug susceptibilities of dermatophytes microconidia and arthroconidia

Objectives: Arthroconidia have been considered as the primary cause of infection by dermatophytes. However, the in vitro antifungal testing evaluates the responses mainly of microconidia or hyphae, and dermatophytes in vivo often produce arthroconidia, a cellular structure presumably more resistant to antifungals. The aim of this study was to compare the in vitro susceptibility of microconidia and arthroconidia of Trichophyton rubrum, Trichophyton tonsurans and Trichophyton equinum to griseofulvin, itraconazole, terbinafine, fluconazole, amphotericin B and hygromycin B. Methods: Microconidia and arthroconidia were produced in vitro, and their susceptibility to each drug was evaluated by assessing the CLSI M38-A broth microdilution method. Results: Arthroconidia of all strains analysed appeared to be more resistant to fluconazole, griseofulvin and itraconazole than microconidia. The MIC of terbinafine was the same for microconidia and arthroconidia for all strains, and the MIC of amphotericin B for microconidia and arthroconidia was the same for isolates of T. equinum and T. tonsurans, but differed for T. rubrum. Finally, the level of resistance of microconidia for all strains towards the antibiotic hygromycin B was from 25 to 400 mg/L. Conclusions: The difference in the susceptibility between microconidia and arthroconidia depends on the drug and on the strain, and may be one of the causes of therapeutic failure. Also, the level of resistance to the antibiotic hygromycin B presented by microconidia of these isolates will allow the use of hygromycin resistance as a dominant marker in fungal transformation procedures in future studies of gene function.

The roles played by Aspergillus nidulans apoptosis-inducing factor (AIF)-like mitochondrial oxidoreductase (AifA) and NADH-ubiquinone oxidoreductases (NdeA-B and NdiA) in farnesol resistance

Farnesol (FOH) is a nonsterol isoprenold produced by dephosphorylanon of farnesyl pyrophosphate a catabolite of the cholesterol biosynthetic pathway These isoprenoids inhibit proliferation and induce apoptosis Here we show that Aspergillus nidulans MA encoding the apoptosis-Inducing factor (AIF)-like mitochondrial oxidoreductase plays a role in the function of the mitochondrial Complex I Additionally we demonstrated that ndeA B and ndiA encode external and internal alternative NADH dehydrogenases respectively that have a function in FOH resistance When exposed to FOH the Delta aifA and Delta ndeA strains have increased ROS production while Delta ndeB Delta ndeA Delta ndeB and Andul mutant strains showed the same ROS accumulation than in the absence of FOH We observed several compensatory mechanisms affecting the differential survival of these mutants to FOH (C) 2010 Elsevier Inc All rights reserved

Distinct resistance mutation and polymorphism acquisition in HIV-1 protease of subtypes B and F1 from children and adult patients under virological failure

The goal of this work was to compare the differences between human immunodeficiency Virus type 1 (HIV-1) of B and F1 Subtypes in the acquisition of major and rninot- protease inhibitor (P1)-associated resistance mutations and of other polymorphisms at the protease (PR) gene, through a cross sectional Study. PR sequences from subtypes B and F1 isolates matched according to P1 exposure time from Brazilian patients were included in this study. Sequences were separated in four groups: 24 and 90 from children and 141 and 99 from adults infected with isolates of subtypes F1 and B, respectively. For comparison, 211 subype B and 79 subtype F1 PR sequences from drug-naive individuals Were included. Demographic and clinical data were similar among B- and F1-infected patients. In untreated patients, Mutations L1OV, K20R, and M361 were more frequent in subtype F1, while L63P, A7IT, and V771 were more prevalent in Subtype B. In treated patients, K20M, D30N, G73S, 184V, and L90M, were More prevalent in subtype B, and K20T and N88S Were more prevalent in Subtype F1. A higher proportion of subtype F1 than Of subtype B Strains Containing other polymorphisms was observed. V82L mutation was Present With increased frequency in isolates from children compared to isolates from adults infected with both subtypes. We could observe a faster resistance emergence in children than in adults, during treatment with protease inhibitors. This data provided evidence that, although rates of overall drug resistance do not differ between subtypes B and F1, the former accumulates resistance at higher proportion in specific amino acid positions of protease when compared to the latter. (c) 2008 Elsevier B.V. All rights reserved.

The relationship between cortisol concentrations in pregnancy and systemic vascular resistance in childhood

Objective. To assess the relationship between cortisol concentrations in the last trimester of pregnancy and systemic vascular resistance — SVR in childhood. Materials and methods. This study is part of a cohort involving 130 Brazilian pregnant women and their children, ages 5 to 7 years. Maternal cortisol was determined in saliva by an enzyme immunoassay utilizing the mean concentration of 9 samples of saliva (3 in each different day), collected at the same time, early in the morning. SVR was assessed by the HDI/PulseWave CR-2000 Cardiovascular Profiling System®. Socioeconomic and demographic characteristics and life style factors were determined by a questionnaire. The nutritional status of the women and children was assessed by the body mass index — BMI. The association between maternal cortisol and SVR in childhood was calculated by multivariate linear regression analysis. Results.There were statistically significant associations between maternal cortisol and SVR (p = 0.043) and BMI-z score of the children (p = 0.027), controlling for maternal BMI, birth weight, age, and gender of the children. Conclusion. As far as we know this is the first study in the literature assessing the association between cortisol concentrations in pregnancy and SVR in childhood. Overall, the data suggest that exposure to excess glucocorticoid in the prenatal period is associated to vascular complications in childhood, predisposing to cardiovascular diseases in later life

The relationship between birth weight and insulin resistance in childhood

Chronic diseases that are typical of adulthood may originate in intra-uterine life through inadequate fetal development. The present epidemiological cohort study of 506 healthy children aged 5\20138 years evaluated the relationship between birth weight and insulin resistance in an age group that has been assessed in few similar studies. Insulin concentration was determined by chemiluminescence and insulin resistance by the homeostasis model assessment (HOMA). Blood glucose, total cholesterol and fractions (LDL cholesterol and HDL cholesterol) and TAG concentrations were determined by automated enzymatic methods. Linear regression analysis investigated the relationship between birth weight (assessed as a continuous variable and in three categories: small for gestational age, SGA; adequate for gestational age and large for gestational age) and the HOMA index, using backward stepwise selection and biological models to explain the causal pathway of the relationship. There were negativeassociations between birth weight (P < 0·001), SGA (P = 0·027) and the HOMA index, and a positive association between waist circumference (P < 0·001) and the HOMA index. Considering the significant associations between birth weight and waist circumference (P < 0·001) and waist circumference and insulin resistance (P < 0·001), we can probably suspect that lower birth weight is a common cause of higher waist circumference and insulin resistance. In summary, the results of the present study showed increased insulin resistance in apparently healthy, young children, who had lower weight at birth and higher measurements of waist circumference. There is a need to develop public health policies that adopt preventive measures to promote adequate maternal-fetal and child development and enable early diagnosis of metabolic abnormalities

Genome wide scan for quantitative trait loci affecting tick resistance in cattle (Bos taurus x Bos indicus)

Background : In tropical countries, losses caused by bovine tick Rhipicephalus (Boophilus) microplus infestation have a tremendous economic impact on cattle production systems. Genetic variation between Bos taurus and Bos indicus to tick resistance and molecular biology tools might allow for the identification of molecular markers linked to resistance traits that could be used as an auxiliary tool in selection programs. The objective of this work was to identify QTL associated with tick resistance/susceptibility in a bovine F2 population derived from the Gyr (Bos indicus) x Holstein (Bos taurus) cross. Results: Through a whole genome scan with microsatellite markers, we were able to map six genomic regions associated with bovine tick resistance. For most QTL, we have found that depending on the tick evaluation season (dry and rainy) different sets of genes could be involved in the resistance mechanism. We identified dry season specific QTL on BTA 2 and 10, rainy season specific QTL on BTA 5, 11 and 27. We also found a highly significant genome wide QTL for both dry and rainy seasons in the central region of BTA 23. Conclusions: The experimental F2 population derived from Gyr x Holstein cross successfully allowed the identification of six highly significant QTL associated with tick resistance in cattle. QTL located on BTA 23 might be related with the bovine histocompatibility complex. Further investigation of these QTL will help to isolate candidate genes involved with tick resistance in cattle.

Evaluation of Primary Resistance to HIV Entry Inhibitors Among Brazilian Patients Failing Reverse Transcriptase/Protease Inhibitors Treatment Reveal High Prevalence of Maraviroc Resistance-Related Mutations

Entry inhibitor is a new class of drugs that target the viral envelope protein. This region is variable; hence resistance to these drugs may be present before treatment. The aim of this study was to analyze the frequency of patients failing treatment with transcriptase reverse and protease inhibitors that would respond to the entry inhibitors Enfuvirtide, Maraviroc, and BMS-806. The study included 100 HIV-1 positive patients from one outpatient clinic in the city of Sao Paulo, for whom a genotype test was requested due to treatment failure. Proviral DNA was amplified and sequenced for regions of gp120 and gp41. A total of 80 could be sequenced and from those, 73 (91.3%), 5 (6.3%) and 2 (2.5%) were classified as subtype B, F, and recombinants (B/F and B/C), respectively. CXCR4 co-receptor use was predicted in 30% of the strains. Primary resistance to Enfuvirtide was found in 1.3%, following the AIDS Society consensus list, and 10% would be considered resistant if a broader criterion was used. Resistance to BMS-806 was higher; 6 (7.5%), and was associated to non-B strains. Strikingly, 27.5% of samples harbored one or more mutation among A316T, I323V, and S405A, which have been related to decreased susceptibility of Maraviroc; 15% of them among viruses predictive to be R5. A more common mutation was A316T, which was associated to the Brazilian B strain harboring the GWGR motif at the tip of V3 loop and their derivative sequences. These results may be impact guidelines for genotype testing and treatment in Brazil.

Genetic polymorphisms in TLR4, CR1 and Duffy genes are not associated with malaria resistance in patients from Baixo Amazonas region, Brazil

The main purpose of this research was to analyze the relation of the genetic polymorphisms frequently expressed by antigen-presenting cells, erythrocytes and malaria susceptibility/resistance with the human malaria infection cases. The sample used consisted of 23 Plasmodium vivax ( Pv)- and P. falciparum ( Pf)-infected patients, and 21 healthy individuals as a control group, from the Baixo Amazonas population in Para, Brazil. The Asp299Gly polymorphisms in the Toll-like receptor 4 ( TLR4), and Gly42Asp, Arg89Cys, Ala100Thr, and T-33C in the Duffy gene ( FY) were analyzed by restriction fragment length polymorphism-polymerase chain reaction. The Lys1590Glu and Arg1601Gly polymorphisms in the complement receptor type 1 (CR1) were analyzed by DNA sequencing. According to the results obtained and statistical analysis considering a significance level or alpha = 0.01, we conclude that the low heterozygote frequency (2.27%) for the Asp299Gly mutation, detected in the TLR4 gene, is not related to the Pv and Pf infections in the patients analyzed. Also, the promoter region GATA-1 analysis of the FY gene in the Pv-infected patients showed that the heterozygote frequency for the T-33C mutation (11.36% of the infected patients and 20.45% of the control patients) is not related to infection resistance. Regarding the CR1 gene, the observed heterozygote frequency (9.09%) for the Arg1601Gly mutation in Pf-infected patients when compared to heterozygote frequency in the control group (18.18%) suggests that there is no correlation with infection resistance.

Evidence for zero-differential resistance states in electronic bilayers

We observe zero-differential resistance states at low temperatures and moderate direct currents in a bilayer electron system formed by a wide quantum well. Several regions of vanishing resistance evolve from the inverted peaks of magneto-intersubband oscillations as the current increases. The experiment, supported by a theoretical analysis, suggests that the origin of this phenomenon is based on instability of homogeneous current flow under conditions of negative differential resistivity, which leads to formation of current domains in our sample, similar to the case of single-layer systems.

High-order fractional microwave-induced resistance oscillations in two-dimensional systems

We report on the observation of microwave-induced resistance oscillations associated with the fractional ratio n/m of the microwave irradiation frequency to the cyclotron frequency for m up to 8 in a two-dimensional electron system with high electron density. The features are quenched at high microwave frequencies independent of the fractional order m. We analyze temperature, power, and frequency dependencies of the magnetoresistance oscillations and discuss them in connection with existing theories.

Microwave-induced Hall resistance in bilayer electron systems

The influence of microwave irradiation on dissipative and Hall resistance in high-quality bilayer electron systems is investigated experimentally. We observe a deviation from odd symmetry under magnetic-field reversal in the microwave-induced Hall resistance boolean AND R(xy), whereas the dissipative resistance boolean AND R(xx) obeys even symmetry. Studies of Delta R(xy) as a function of the microwave electric field and polarization exhibit a strong and nontrivial power and polarization dependence. The obtained results are discussed in connection to existing theoretical models of microwave-induced photoconductivity.

Low-bias negative differential resistance in graphene nanoribbon superlattices

We theoretically investigate negative differential resistance (NDR) for ballistic transport in semiconducting armchair graphene nanoribbon (aGNR) superlattices (5 to 20 barriers) at low bias voltages V(SD) < 500 mV. We combine the graphene Dirac Hamiltonian with the Landauer-Buttiker formalism to calculate the current I(SD) through the system. We find three distinct transport regimes in which NDR occurs: (i) a ""classical"" regime for wide layers, through which the transport across band gaps is strongly suppressed, leading to alternating regions of nearly unity and zero transmission probabilities as a function of V(SD) due to crossing of band gaps from different layers; (ii) a quantum regime dominated by superlattice miniband conduction, with current suppression arising from the misalignment of miniband states with increasing V(SD); and (iii) a Wannier-Stark ladder regime with current peaks occurring at the crossings of Wannier-Stark rungs from distinct ladders. We observe NDR at voltage biases as low as 10 mV with a high current density, making the aGNR superlattices attractive for device applications.

Resistance Training with Vascular Occlusion in Inclusion Body Myositis: A Case Study

GUALANO, B., M. NEVES JR, F. R. LIMA, A. L. PINTO, G. LAURENTINO, C. BORGES, L. BAPTISTA, G. G. ARTIOLI, M. S. AOKI, A. MORISCOT, A. H. LANCHA JR, E. BONFA, and C. UGRINOWITSCH. Resistance Training with Vascular Occlusion in Inclusion Body Myositis: A Case Study. Med Sci. Spot-is Exerc., Vol. 42, No. 2, pp. 250-254, 2010. Inclusion body myositis (IBM) is a rare idiopathic inflammatory myopathy that produces remarkable muscle weakness. Resistance training with vascular occlusion has been shown to improve muscle strength and cross-sectional area in other muscle wasting conditions. Purpose: We evaluated the efficacy of a moderate-intensity resistance training program combined with vascular occlusion by examining functional capacity, muscle morphology, and changes in the expression of genes related to muscle protein synthesis and proteolysis in a patient with IBM. Methods: A 65-yr-old man with IBM resistant to all proposed treatments underwent resistance training with vascular occlusion for 12 wk. Leg press one-repetition maximum; thigh cross-sectional area; balance, mobility, and muscle function; quality of life; and blood markers of inflammation and muscle damage were assessed at baseline and after the 12-wk program. The messenger RNA (mRNA) expression levels of mechanogrowth factor, mammalian target of rapamycin, atrogin-1, and muscle RING finger-1 were also quantified. Results: After the 12-wk training program, the patient`s leg press one-repetition maximum, balance and mobility function, and thigh cross-sectional area increased 15.9%, 60%, and 4.7%, respectively. All Short Form-36 Health Survey Questionnaire subscales demonstrated improvements as well, varying from 18% to 600%. mRNA expression of mechanogrowth factor increased 3.97-fold, whereas that of atrogin-1 decreased 0.62-fold. Muscle RING finger-1 and mammalian target of rapamycin mRNA levels were only slightly altered, 1.18- and 1.28-fold, respectively. Importantly, the exercise did not induce disease flare. Conclusions: We describe a novel, and likely the first, nonpharmacological therapeutic tool that might be able to counteract the muscle atrophy and the declining strength that usually occur in IBM.

A TR beta-selective agonist confers resistance to diet-induced obesity

Thyroid hormone receptor beta (TR beta also listed as THRB oil the MGI Database)-selective agonists activate brown adipose tissue (BAT) thermogenesis, while only minimally affecting cardiac activity or lean body mass. Here, we tested the hypothesis that daily administration of the TR beta agonist GC-24 prevents the metabolic alterations associated with a hypercaloric diet. Rats were placed on a high-fat diet and after a month exhibited increased body weight (BW) and adiposity, fasting hyperglycemia and glucose intolerance, increased plasma levels of triglycerides, cholesterol, nonesterified Fatty acids and interleukin-6. While GC-24 administration to these animals did not affect food ingestion or modified the progression of BW gain, it did increase energy, g the increase in adiposity Without expenditure, eliminating causing cardiac hypertrophy Fasting hyperglycemia remained unchanged, but treatment with GC-24 improved glucose I tolerance by increasing insulin Sensitivity and also normalized plasma triglyceride levels. plasma cholesterol levels were only Partially normalized and liver cholesterol content remained high in the GC-24-treated animals. Gene expression in liver, skeletal muscle, and white adipose tissue was only minimally affected by treatment with GC-24, with the main target being BAT In conclusion, during high-fat feeding treatment with the TR beta-selective agonist, GC-24 only partially improves metabolic control probably as a result Of accelerating the resting metabolic rate. Journal of Endocrinology (2009) 203, 291-299