Reproducibility of the Structural Connectome Reconstruction across Diffusion Methods

Analysis of the structural connectomes can lead to powerful insights about the brain's organization and damage. However, the accuracy and reproducibility of constructing the structural connectome done with different acquisition and reconstruction techniques is not well defined. In this work, we evaluated the reproducibility of the structural connectome techniques by performing test‐retest (same day) and longitudinal studies (after 1 month) as well as analyzing graph‐based measures on the data acquired from 22 healthy volunteers (6 subjects were used for the longitudinal study). We compared connectivity matrices and tract reconstructions obtained with the most typical acquisition schemes used in clinical application: diffusion tensor imaging (DTI), high angular resolution diffusion imaging (HARDI), and diffusion spectrum imaging (DSI). We observed that all techniques showed high reproducibility in the test‐retest analysis (correlation >.9). However, HARDI was the only technique with low variability (2%) in the longitudinal assessment (1‐month interval). The intraclass coefficient analysis showed the highest reproducibility for the DTI connectome, however, with more sparse connections than HARDI and DSI. Qualitative (neuroanatomical) assessment of selected tracts confirmed the quantitative results showing that HARDI managed to detect most of the analyzed fiber groups and fanning fibers. In conclusion, we found that HARDI acquisition showed the most balanced trade‐off between high reproducibility of the connectome, higher rate of path detection and of fanning fibers, and intermediate acquisition times (10‐15 minutes), although at the cost of higher appearance of aberrant fibers.     

Barriers and facilitators to PrEP for transwomen in Brazil

Pre-exposure prophylaxis (PrEP) is an important biomedical intervention that may help reduce the risk of HIV transmission among transwomen. To date, little research is available to inform interventions to increase uptake and adherence to PrEP among transwomen, especially in places outside the U.S. We conducted a qualitative study in 2015 with 34 adult transwomen in Rio de Janeiro, Brazil and assessed awareness, interest, barriers and facilitators to PrEP uptake and adherence for transwomen. Almost one third of participants had heard of PrEP, and most were interested and thought it would be beneficial for transwomen in their community. Barriers to PrEP included fear of being HIV positive resulting in low HIV testing and concerns about the ability to adhere to a daily PrEP regimen. The most prominent barrier to uptake was past experiences of transgender-identity related discrimination in the universal health care system that reduced willingness to seek PrEP or health care in general. Participants recommended technological solutions to PrEP health education information that could address uptake and adherence. This study informs efforts to increase PrEP use among transwomen in Brazil.     

Hypertrophic pyloric stenosis in the adult

In view of the low incidence of hypertrophic pyloric stenosis, we present a case of this pathology in a male aged 74. Stenosis was of the diffuse type, associated with gastric ulcer and chronic atrophic gastritis. The patient was admitted to our Service with upper digestive tract hemorrhage after deterioration of the ulcer.     

Are cardiovascular and metabolic responses to field walking tests interchangeable and obesity-dependent?

Purpose: To investigate if cardiovascular and metabolic responses to the six-minute walk test (6MWT) and incremental shuttle walking test (ISWT) are in agreement with cardiopulmonary exercise testing (CPX) and determine if both submaximal tests are interchangeable in obese and eutrophic individuals.

Method: Observational and cross-sectional study included 51 obese women (ObG) and 21 controls (CG) (20–45 years old). Subjects underwent clinical evaluation, CPX, the 6MWT and ISWT. We applied Bland–Altman plots to assess agreement between walking tests and CPX. Correlation analysis assessed relationships between key variables.

Results: There was an agreement between CPX and both the 6MWT [oxygen uptake (VO₂ mL?kg^?1?min^?1)?=?6.9 (CI: 5.7–8.1), and heart rate (bpm)?=?37.0 (CI: 33.3–40.7)] and ISWT [VO₂ (mL?kg^?1?min^?1)?=?6.1 (CI: 4.9–7.3), and heart rate (bpm)?=?36.2 (CI: 32.1–40.3)]. We found similar cardiovascular and metabolic responses to both tests in the ObG but not in the CG. Strong correlations were demonstrated between 6MWT and ISWT variables: VO₂ ( r?=?0.70); dyspnoea (r?=?0.80); and leg fatigue (r?=?0.70).

Conclusions: 6MWT and ISWT may both hold interchangeable clinical value when contrasted with CPX in obese women and may be a viable alternative in the clinical setting when resources and staffing are limited.

• Implications for Rehabilitation

• Obesity is a worldwide epidemic, with high prevalence in women, and it is associated to impaired cardiorespiratory fitness and functional capacity as well as high mortality risk.

• Assessing oxygen uptake by means of cardiopulmonary exercise testing is the gold standard method for evaluating and stratifying cardiorespiratory fitness, however it is not ever applied due to costs and staffing.

• Walking field tests may be a cost-effective approach that provides valuable information regarding the functional capacity in agreement to metabolic and cardiovascular responses of cardiopulmonary exercise testing.

     

Preliminary clinical studies of C-reactive protein quantified by enzyme-linked immunoassay

We have used an enzyme-linked immunoassay technique to quantify human C-reactive protein (CRP). In this assay phosphorylethanolamine is covalently linked to polystyrene wells. Serum or plasma specimens are diluted 961-fold and assayed. After Ca2+-dependent binding of CRP to the plates, the complex is reacted with peroxidase-labeled anti-CRP antibody. The response varies linearly with CRP concentrations between 10 and 160 mg/L; the detection limit is 0.34 ng per well. The results correlate well (r greater than or equal to 0.90) with those of rate nephelometry. This new method can be automated, is not subject to interferences or cross reactivity, is highly reproducible, has low background values, and can be carried out at room temperature.     

Acute cardiovascular effects of magnesium and their relationship to systemic and myocardial magnesium concentrations after short infusion in awake sheep

The temporal relationship between the systemic and myocardial concentrations of magnesium and some of its acute cardiovascular effects were examined after short i.v. infusion administration of magnesium (30 mmol over 2 min) in five awake chronically instrumented sheep. Magnesium decreased mean arterial blood pressure and systemic vascular resistance (SVR) by 23 and 41% from baseline, respectively. These hemodynamic changes were consistent with magnesium producing primary reductions in SVR with partial heart rate (HR)-mediated compensation of blood pressure. Cardiac output and HR increased by 38 and 38% from baseline, respectively. Magnesium had little effect on myocardial contractility, but substantially increased myocardial blood flow (MBF, 77% above baseline) primarily due to direct myocardial vasodilation. The peak arterial and coronary sinus serum magnesium concentrations were 6.94 +/- 0.26 (mean +/- S.E.M.) and 6.51 +/- 0.20 mM, respectively, at 2 min. Both arterial and coronary sinus magnesium concentrations at the end of the study were still more than 3 mM, whereas all the cardiovascular effects were back to baseline. The myocardial kinetics of magnesium was consistent with rapid equilibration of magnesium (half-life 0.4 min) with a small distribution volume (71 ml) consistent with the extracellular space of the heart. In conclusion, magnesium was shown to have a rapid equilibration between the plasma/serum concentrations of magnesium and its extracellular concentration in the myocardium. However, the primary cardiovascular effect of magnesium (reductions in SVR) preceded its extracellular concentrations, and was a direct function of its arterial concentration. A "threshold" model for changes in SVR was preferred when linked to the arterial magnesium concentration.     

Seguimiento a largo plazo del cabestrillo AdVance®/AdVanceXP®. ¿Qué piensa el cirujano?, ¿qué piensa el paciente?

Objectives

To analyse the safety, efficacy and quality of life of patients with male stress urinary incontinence after radical prostatectomy treated with the AdVance^® and AdvanceXP^® slings.

Synthesis and antileishmanial activities of novel 3-substituted quinolines

The antileishmanial efficacy of four novel quinoline derivatives was determined in vitro against Leishmania chagasi, using extracellular and intracellular parasite models. When tested against L. chagasi-infected macrophages, compound 3b demonstrated 8.3-fold greater activity than did the standard pentavalent antimony. No significant activity was found for compounds 3a, 4a, and 4b. The antilesihmanial effect of compound 3b was independent of host cell activation, as demonstrated by nitric oxide production. Ultrastructural studies of promastigotes treated with compound 3b showed mainly enlarged mitochondria, with matrix swelling and reduction in the number of cristae. Synthetic analogues based on the quinoline ring structure, already an established template for antiparasitic drugs, could provide further useful compounds.