Antiretroviral resistance among HIV type 1-infected women first exposed to antiretrovirals during pregnancy: Plasma versus PBMCs

Resistance-associated mutations (RAMs) in plasma samples from HIV-1-infected women who received antiretroviral (ARV) prophylaxis during pregnancy was assessed and correlated with the detection of RAMs in peripheral blood mononuclear cells (PMBCs). The study population was composed of HIV-1-infected women enrolled in a prospective cohort study in Latin America and the Caribbean (NISDI Perinatal Study) as of March 1, 2005, who were diagnosed with HIV-1 infection during the current pregnancy, who received ARVs during pregnancy for prevention of mother-to-child transmission of HIV-1, and who were followed through at least the 6-12 week postpartum visit. Plasma samples collected at enrollment during pregnancy and at 6-12 weeks postpartum were assayed for RAMs. Plasma results were compared to previously described PBMC results from the same study population. Of 819 enrolled subjects, 197 met the eligibility criteria. Nucleic acid amplification was accomplished in 123 plasma samples at enrollment or 6-12 weeks postpartum, and RAMs were detected in 22 (17.9%; 95% CI: 11.7-25.9%). Previous analyses had demonstrated detection of RAMs in PBMCs in 19 (16.1%). There was high concordance between RAMs detected in plasma and PBMC samples, with only eight discordant pairs. The prevalence of RAMs among these pregnant, HIV-1-infected women is high (>15%). Rates of detection of RAMs in plasma and PBMC samples were similar.

Effect of Titanium Tetrafluoride and Amine Fluoride Treatment Combined with Carbon Dioxide Laser Irradiation on Enamel and Dentin Erosion

Objective: This in vitro study aimed to analyze the influence of carbon dioxide (CO(2)) laser irradiation on the efficacy of titanium tetrafluoride (TiF(4)) and amine fluoride (AmF) in protecting enamel and dentin against erosion. Methods: Bovine enamel and dentin samples were pretreated with carbon dioxide (CO(2)) laser irradiation only (group I), TiF(4) only (1% F, group II), CO(2) laser irradiation before (group III) or through (group IV) TiF(4) application, AmF only (1% F, group V), or CO(2) laser irradiation before (group VI) or through (group VII) AmF application. Controls remained untreated. Ten samples of each group were then subjected to an erosive demineralization and remineralization cycling for 5 days. Enamel and dentin loss were measured profilometrically after pretreatment, 4 cycles (1 day), and 20 cycles (5 days) and statistically analyzed using analysis of variance and Scheffe's post hoc tests. Scanning electron microscopy (SEM) analysis was performed in pretreated but not cycled samples (two samples each group). Results: After 20 cycles, there was significantly less enamel loss in groups V and IV and significantly less dentin loss in group V only. All other groups were not significantly different from the controls. Lased surfaces (group I) appeared unchanged in the SEM images, although SEM images of enamel but not of dentin showed that CO(2) laser irradiation affected the formation of fluoride precipitates. Conclusion: AmF decreased enamel and dentin erosion, but CO(2) laser irradiation did not improve its efficacy. TiF(4) showed only a limited capacity to prevent erosion, but CO(2) laser irradiation significantly enhanced its ability to reduce enamel erosion.

In Vitro Evaluation of Enamel Erosion After Nd:YAG Laser Irradiation and Fluoride Application

Objective: Previous investigations have demonstrated improved enamel demineralization resistance after laser irradiation. Due to the possibility of a synergistic effect between laser and fluoride, this study investigated the effect of fluoridated agents and Nd:YAG irradiation separately and in combination on enamel resistance to erosion. Methods: One hundred bovine enamel blocks were randomly divided into 10 groups: G1, untreated (control); G2, acidic phosphate fluoride (APF) (1.23% F) for 4 min; G3, fluoride varnish for 6 h (NaF, 2.26%); G4, 0.5 W Nd: YAG laser (250 mm pulse width, 10 Hz, 35 J/cm(2), with uniform velocity for 30 sec in each application); G5, 0.75 W Nd:YAG laser (52.5 J/cm(2)); G6, 1.0 W Nd:YAG laser (70 J/cm(2)); G7, APF + 0.75 W Nd:YAG laser; G8, 0.75 W Nd:YAG laser + APF; G9, fluoride varnish + 0.75 W Nd:YAG laser; and G10, 0.75 W Nd:YAG laser + fluoride varnish. During 10 d the erosive cycle was conducted by immersion of the blocks in Sprite light for 1 min, followed by immersion in artificial saliva for 59 min. This procedure was consecutively repeated four times per day. In each day, during the remaining 20 h, the blocks were maintained in artificial saliva. The wear was evaluated by profilometry (days 5 and 10). Data were tested by two-way ANOVA and Bonferroni's tests (p < 0.05). Results: The mean wear at days 5 and 10 was, respectively: G1, 1.83 and 2.67 mu m; G2, 1.04 and 2.60 mu m; G3, 1.03 and 2.48 mu m; G4, 1.13 and 2.47 mu m; G5, 1.07 and 2.44 mu m; G6, 1.0 and 2.35 mu m; G7, 0.75 and 2.27 mu m; G8, 0.80 and 2.12 mu m; G9, 0.76 and 2.47 mu m; and G10, 1.09 and 2.46 mu m. At day 5, all the experimental groups presented significant lesser wear when compared to control group. However, at 10 d, only G7 and G8 were still different from control. Conclusions: The association between APF application and laser irradiation seems to be an alternative preventive measure against dental erosion.

Effect of Nd:YAG Irradiation and Fluoride Application on Dentine Resistance to Erosion in Vitro

Objective: In this paper we evaluated the effect of two fluoridated agents and Nd:YAG irradiation separately and in combination on dentine resistance to erosion. Background Data: The morphological changes in dentin induced by laser treatment may reduce the progression of erosive lesions. Due to the possibility of a synergistic effect of laser with fluoride, this study was conducted. Materials and Methods: Eighty bovine dentine samples (4 x 4 mm) were randomly divided into eight groups, according to the following treatments: G1: untreated (control); G2: acidic phosphate fluoride gel (APF 1.23%) for 4 min; G3: fluoride varnish (NaF 2.26%) for 6 h; G4: 0.5 W Nd: YAG laser (250 mu sec pulse, 10 Hz, 35 J/cm(2), 30 sec); G5: 0.75 W Nd: YAG laser (52.5 J/cm(2)); G6: 1.0 W Nd: YAG laser (70 J/cm(2)); G7: APF + 0.75 W Nd: YAG laser; and G8: NaF + 0.75 W Nd: YAG laser. After the treatments, half of each dentine surface was protected with nail varnish. The samples were stored in artificial saliva (30 mL/sample) for 24 h and submitted to four erosive 1-min cycles. Between the erosive attacks, the blocks were maintained in artificial saliva for 59 min. The erosive wear was evaluated by profilometry. Results: The mean wear (+/- SD, mu m) was: G1: 1.20 +/- 0.20; G2: 0.47 +/- 0.06; G3: 0.81 +/- 0.11; G4: 1.47 +/- 0.32; G5: 1.52 +/- 0.24; G6: 1.49 +/- 0.30; G7: 0.49 +/- 0.11; and G8: 1.06 +/- 0.31 (Tukey's test, p < 0.05). Conclusions: Laser irradiation was not able to reduce dentine erosion. However, fluoride application was able to increase the dentine's resistance to erosion, and APF showed better results than fluoride varnish.

Deep sequencing of New World screw-worm transcripts to discover genes involved in insecticide resistance

Background: The New World screw-worm (NWS), Cochliomyia hominivorax, is one of the most important myiasis-causing flies, causing severe losses to the livestock industry. In its current geographical distribution, this species has been controlled by the application of insecticides, mainly organophosphate (OP) compounds, but a number of lineages have been identified that are resistant to such chemicals. Despite its economic importance, only limited genetic information is available for the NWS. Here, as a part of an effort to characterize the C. hominivorax genome and identify putative genes involved in insecticide resistance, we sampled its transcriptome by deep sequencing of polyadenylated transcripts using the 454 sequencing technology. Results: Deep sequencing on the 454 platform of three normalized libraries (larval, adult male and adult female) generated a total of 548,940 reads. Eighteen candidate genes coding for three metabolic detoxification enzyme families, cytochrome P450 monooxygenases, glutathione S transferases and carboxyl/cholinesterases were selected and gene expression levels were measured using quantitative real-time polymerase chain reaction (qRT-PCR). Of the investigated candidates, only one gene was expressed differently between control and resistant larvae with, at least, a 10-fold down-regulation in the resistant larvae. The presence of mutations in the acetylcholinesterase (target site) and carboxylesterase E3 genes was investigated and all of the resistant flies presented E3 mutations previously associated with insecticide resistance. Conclusions: Here, we provided the largest database of NWS expressed sequence tags that is an important resource, not only for further studies on the molecular basis of the OP resistance in NWS fly, but also for functional and comparative studies among Calliphoridae flies. Among our candidates, only one gene was found differentially expressed in resistant individuals, and its role on insecticide resistance should be further investigated. Furthermore, the absence of mutations in the OP target site and the high frequency of mutant carboxylesterase E3 indicate that metabolic resistance mechanisms have evolved predominantly in this species.

Model Independent Tests of Skyrmions and Their Holographic Cousins

We describe a new exact relation for large N(c) QCD for the long-distance behavior of baryon form factors in the chiral limit. This model-independent relation is used to test the consistency of the structure of several baryon models. All 4D semiclassical chiral soliton models satisfy the relation, as does the Pomarol-Wulzer holographic model of baryons as 5D Skyrmions. However, remarkably, we find that the holographic model treating baryons as instantons in the Sakai-Sugimoto model does not satisfy the relation.

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.

Microwave Zero-Resistance States in a Bilayer Electron System

Magnetotransport measurements on a high-mobility electron bilayer system formed in a wide GaAs quantum well reveal vanishing dissipative resistance under continuous microwave irradiation. Profound zero-resistance states (ZRS) appear even in the presence of additional intersubband scattering of electrons. We study the dependence of photoresistance on frequency, microwave power, and temperature. Experimental results are compared with a theory demonstrating that the conditions for absolute negative resistivity correlate with the appearance of ZRS.

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.

Universal resistance capacitance crossover in current-voltage characteristics for unshunted array of overdamped Nb-AlOx-Nb Josephson junctions

We report on some unusual behavior of the measured current-voltage characteristics (CVC) in artificially prepared two-dimensional unshunted array of overdamped Nb-AlO(x)-Nb Josephson junctions. The obtained nonlinear CVC are found to exhibit a pronounced (and practically temperature independent) crossover at some current I(cr) = (1/2 beta(C)-1)I(C) from a resistance R dominated state with V(R)=R root I(2)-I(C)(2) below I(cr) to a capacitance C dominated state with V(C) = root(h) over bar /4eC root I-I(C) above I(cr). The origin of the observed behavior is discussed within a single-plaquette approximation assuming the conventional resistively shunted junction model with a finite capacitance and the Ambegaokar-Baratoff relation for the critical current of the single junction. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3407566]

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.

Effect of different resistance-training regimens on the WNT-signaling pathway

The purpose of the present study was to evaluate the effects of 8 weeks of strength and power training on the expression of genes related to the canonical WNT pathway and beta-catenin protein levels in physically active men. Twenty-five subjects (27.4 +/- A 4.6 years) were balanced based on their relative maximum strength in the squat exercise (squat 1RM/body mass) and randomly assigned to strength training (ST) (n = 10), power training (PT) (n = 10), and control (C) (n = 5) groups. The ST and the PT groups performed high and low intensity squats, respectively, thrice a week, for 8 weeks. Muscle biopsies from the vastus lateralis muscle were collected before and after the training period. Relative strength and power increased similarly in both ST and PT groups (P < 0.001). Fiber cross-sectional area also increased similarly in both ST and PT groups. Gene expression and beta-catenin protein expression levels were assessed by real-time PCR and Western blot. Certain genes were up-regulated in the ST group (WNT1: 6.4-fold, P < 0.0001; SFRP1: 3.3-fold, P < 0.0001 and LEF1: 7.3-fold, P < 0.0001) and also in the PT group (WNT1: 24.9-fold, P < 0.0001; SFRP1: 2.7-fold, P < 0.0001; LEF1: 34.1-fold, P < 0.0001 and Cyclin D1: 7.7-fold, P < 0.001). In addition, the expression of key WNT pathway genes was substantially more responsive to PT than to ST (WNT1: P < 0.0001; LEF1: P < 0.0001 and Cyclin D1: P < 0.001). Finally, the total beta-catenin protein content increased only in the PT group (P < 0.05). Our data indicate that a PT regimen triggers greater responses in key elements of the WNT pathway.

The accuracy of the Clock Drawing Test compared to that of standard screening tests for Alzheimer`s disease: results from a study of Brazilian elderly with heterogeneous educational backgrounds

Background: Although the Clock Drawing Test (CDT) is the second most used test in the world for the screening of dementia, there is still debate over its sensitivity specificity, application and interpretation in dementia diagnosis. This study has three main aims: to evaluate the sensitivity and specificity of the CDT in a sample composed of older adults with Alzheimer`s disease (AD) and normal controls; to compare CDT accuracy to the that of the Mini-mental State Examination (MMSE) and the Cambridge Cognitive Examination (CAMCOG), and to test whether the association of the MMSE with the CDT leads to higher or comparable accuracy as that reported for the CAMCOG. Methods: Cross-sectional assessment was carried out for 121 AD and 99 elderly controls with heterogeneous educational levels from a geriatric outpatient clinic who completed the Cambridge Examination for Mental Disorder of the Elderly (CAMDEX). The CDT was evaluated according to the Shulman, Mendez and Sunderland scales. Results: The CDT showed high sensitivity and specificity. There were significant correlations between the CDT and the MMSE (0.700-0.730; p < 0.001) and between the CDT and the CAMCOG (0.753-0.779; p < 0.001). The combination of the CDT with the MMSE improved sensitivity and specificity (SE = 89.2-90%; SP = 71.7-79.8%). Subgroup analysis indicated that for elderly people with lower education, sensitivity and specificity were both adequate and high. Conclusions: The CDT is a robust screening test when compared with the MMSE or the CAMCOG, independent of the scale used for its interpretation. The combination with the MMSE improves its performance significantly, becoming equivalent to the CAMCOG.

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.