Reliability of electromyographic amplitude values of the upper limb muscles during closed kinetic chain exercises with stable and unstable surfaces

The purpose of the present study was to evaluate the intra and interday reliability of surface electromyographic amplitude values of the scapular girdle muscles and upper limbs during 3 isometric closed kinetic chain exercises, involving upper limbs with the fixed distal segment extremity on stable base of support and on a Swiss ball (relatively unstable). Twenty healthy adults performed the exercises push-up, bench-press and wall-press with different effort levels (80% and 100% maximal load). Subjects performed three maximal voluntary contractions (MVC) in muscular testing position of each muscle to obtain a reference value for root mean square (RMS) normalization. Individuals were instructed to randomly perform three isometric contraction series, in which each exercise lasted 6 s with a 2-min resting-period between series and exercises. Intra and interday reliabilities were calculated through the intraclass correlation coefficient (ICC 2.1), standard error of the measurement (SEM). Results indicated an excellent intraday reliability of electromyographic amplitude values (ICC ? 0.75). The interday reliability of normalized RMS values ranged between good and excellent (ICC 0.52–0.98). Finally, it is suggested that the reliability of normalized electromyographic amplitude values of the analyzed muscles present better values during exercises on a stable surface. However, load levels used during the exercises do not seem to have any influence on variability levels, possibly because the loads were quite similar.     

Behavioural patterns of sea lampreys' spawning migration through difficult passage areas, studied by electromyogram telemetry

Electromyogram telemetry (EMG) was used to study the behaviour of sea lamprey Petromyzon marinus during migration through difficult passage areas. When swimming on stretches free from obstacles, the EMG values of sea lampreys showed a constant pattern of activity. Conversely, when negotiating difficult passage areas their behaviour were characterized by alternating between short bursts of intense activity ( i.e . burst movements) and periods of motionless rest during which sea lampreys attached to convenient structures by means of the oral sucker. During blockstone weirs negotiation, tagged sea lampreys spent on average 23% of the time swimming rapidly by means of multiple bouts of burst movements of 31 s duration. To recover from each burst movement, the sea lampreys spent on average 2 min 25 s resting. Sea lampreys seemed affected by increasing fatigue, which probably resulted from initiating a new burst movement without fully recovering physiologically from the previous efforts.     

A new karyological variant of Oecomys (Rodentia: Sigmodontinae) and its phylogenetic relationship based on molecular data.

A new karyological variant of the Sigmodontinae genus Oecomys was detected in specimens from Brazilian Pantanal. Karyologic analyses showed 2n = 72 and FN = 90, which differs from all known chromosomal complements of the genus. This new karyomorph showed distinctive morphological attributes and could not be attributed to any described Oecomys species. Molecular analysis using cytochrome-b sequence data suggested the monophyly of Oecomys. Maximum-likelihood analyses placed the Oecomys sp. haplotype clade as the sister branch to Oecomys bicolor, whereas maximum-parsimony analyses did not resolve its relationship with the other Oecomys species. Kimura's two parameters distance estimates between this and other Oecomys species are high, and active gene flow has been found not to coexist with these divergence estimates.     

GROWTH AND ULTRASTRUCTURAL CHANGES IN DICTYOSPHAERIUM PULCHELLUM EXPOSED TO COPPER (CHLOROCOCCALES,CHLOROPHYCEAE)

In an assay addressing the toxicity of copper to Dictyosphaerium pulchellum, a 48 hours' exposure of axenic cultures of the alga to metal concentrations ranging from 0 to 300 mg L^?1 caused a significant decrease in the growth rate and cell chlorophyll content. Extracellular mucilage remotion by controlled sonication before exposure to copper emphasized chlorophyll content reduction, but not cellular density diminution. Because mucilage acts as a cation interchanger, these results suggested that, during at least the first 48 hours, division rates might be affected by lower Cu⁺² concentrations than chlorophyll content. Ultrastructural observations showed that the normal organization of the chloroplasts was altered; they presented dilated lamellae, irregularly arranged with practically no stacking. Copper precipitates were mainly observed outside the plasmalemma or within the extracellular mucilage. Electron probe microanalysis confirmed these observations, showing only minor precipitates inside the cells.     

Proteomic Analysis of Trypanosoma cruzi Response to Ionizing Radiation Stress

Trypanosoma cruzi, the causative agent of Chagas disease, is extremely resistant to ionizing radiation, enduring up to 1.5 kGy of gamma rays. Ionizing radiation can damage the DNA molecule both directly, resulting in double-strand breaks, and indirectly, as a consequence of reactive oxygen species production. After a dose of 500 Gy of gamma rays, the parasite genome is fragmented, but the chromosomal bands are restored within 48 hours. Under such conditions, cell growth arrests for up to 120 hours and the parasites resume normal growth after this period. To better understand the parasite response to ionizing radiation, we analyzed the proteome of irradiated (4, 24, and 96 hours after irradiation) and non-irradiated T. cruzi using two-dimensional differential gel electrophoresis followed by mass spectrometry for protein identification. A total of 543 spots were found to be differentially expressed, from which 215 were identified. These identified protein spots represent different isoforms of only 53 proteins. We observed a tendency for overexpression of proteins with molecular weights below predicted, indicating that these may be processed, yielding shorter polypeptides. The presence of shorter protein isoforms after irradiation suggests the occurrence of post-translational modifications and/or processing in response to gamma radiation stress. Our results also indicate that active translation is essential for the recovery of parasites from ionizing radiation damage. This study therefore reveals the peculiar response of T. cruzi to ionizing radiation, raising questions about how this organism can change its protein expression to survive such a harmful stress.     

System Dynamics Modeling in the Evaluation of Delays of Care in ST-Segment Elevation Myocardial Infarction Patients within a Tiered Health System

Background

Mortality rates amongst ST segment elevation myocardial infarction (STEMI) patients remain high, especially in developing countries. The aim of this study was to evaluate the factors related with delays in the treatment of STEMI patients to support a strategic plan toward structural and personnel modifications in a primary hospital aligning its process with international guidelines.

Methods and Findings

The study was conducted in a primary hospital localized in Foz do Iguaçu, Brazil. We utilized a qualitative and quantitative integrated analysis including on-site observations, interviews, medical records analysis, Qualitative Comparative Analysis (QCA) and System Dynamics Modeling (SD). Main cause of delays were categorized into three themes: a) professional, b) equipment and c) transportation logistics. QCA analysis confirmed four main stages of delay to STEMI patient’s care in relation to the ‘Door-in-Door-out’ time at the primary hospital. These stages and their average delays in minutes were: a) First Medical Contact (From Door-In to the first contact with the nurse and/or physician): 7 minutes; b) Electrocardiogram acquisition and review by a physician: 28 minutes; c) ECG transmission and Percutaneous Coronary Intervention Center team feedback time: 76 minutes; and d) Patient’s Transfer Waiting Time: 78 minutes. SD baseline model confirmed the system’s behavior with all occurring delays and the need of improvements. Moreover, after model validation and sensitivity analysis, results suggested that an overall improvement of 40% to 50% in each of these identified stages would reduce the delay.

Conclusions

This evaluation suggests that investment in health personnel training, diminution of bureaucracy, and management of guidelines might lead to important improvements decreasing the delay of STEMI patients’ care. In addition, this work provides evidence that SD modeling may highlight areas where health system managers can implement and evaluate the necessary changes in order to improve the process of care.     

Vitamin D Deficiency Aggravates Nephrotoxicity,Hypertension and Dyslipidemia Caused by Tenofovir: Role of Oxidative Stress and Renin-Angiotensin System

Vitamin D deficiency (VDD) is prevalent among HIV-infected individuals. Vitamin D has been associated with renal and cardiovascular diseases because of its effects on oxidative stress, lipid metabolism and renin-angiotensin-aldosterone system (RAAS). Tenofovir disoproxil fumarate (TDF), a widely used component of antiretroviral regimens for HIV treatment, can induce renal injury. The aim of this study was to investigate the effects of VDD on TDF-induced nephrotoxicity. Wistar rats were divided into four groups: control, receiving a standard diet for 60 days; VDD, receiving a vitamin D-free diet for 60 days; TDF, receiving a standard diet for 60 days with the addition of TDF (50 mg/kg food) for the last 30 days; and VDD+TDF receiving a vitamin D-free diet for 60 days with the addition of TDF for the last 30 days. TDF led to impaired renal function, hyperphosphaturia, hypophosphatemia, hypertension and increased renal vascular resistance due to downregulation of the sodium-phosphorus cotransporter and upregulation of angiotensin II and AT1 receptor. TDF also increased oxidative stress, as evidenced by higher TBARS and lower GSH levels, and induced dyslipidemia. Association of TDF and VDD aggravated renovascular effects and TDF-induced nephrotoxicity due to changes in the redox state and involvement of RAAS.     

Acute Chagas Disease: New Global Challenges for an Old Neglected Disease

Chagas disease is caused by infection with the protozoan Trypanosoma cruzi, and although over 100 years have passed since the discovery of Chagas disease, it still presents an increasing problem for global public health. A plethora of information concerning the chronic phase of human Chagas disease, particularly the severe cardiac form, is available in the literature. However, information concerning events during the acute phase of the disease is scarce. In this review, we will discuss (1) the current status of acute Chagas disease cases globally, (2) the immunological findings related to the acute phase and their possible influence in disease outcome, and (3) reactivation of Chagas disease in immunocompromised individuals, a key point for transplantation and HIV infection management.