Dafne Herrero

Involvement of the atrial natriuretic peptide in cardiovascular pathophysiology and its relationship with exercise

In this minireview we describe the involvement of the atrial natriuretic peptide (ANP) in cardiovascular pathophysiology and exercise. The ANP has a broad homeostatic role and exerts complex effects on the cardio-circulatory hemodynamics, it is produced by the left atrium and has a key role in regulating sodium and water balance in mammals and humans. The dominant stimulus for its release is atrial wall tension, commonly caused by exercise. The ANP is involved in the process of lipolysis through a cGMP signaling pathway and, as a consequence, reducing blood pressure by decreasing the sensitivity of vascular smooth muscle to the action of vasoconstrictors and regulate fluid balance. The increase of this hormone is associated with better survival in patients with chronic heart failure (CHF). This minireview provides new evidence based on recent studies related to the beneficial effects of exercise in patients with cardiovascular disease, focusing on the ANP.

Motor development of infants exposed to maternal human immunodeficiency virus (HIV) but not infected.

Background To assess the motor development of infants exposed to maternal human immunodeficiency virus (HIV). Methods Thirty infants were assessed in the period from November 2009 to March 2010 at the AIDS Reference and Training Centre, in São Paulo, Brazil. The assessment instrument used in the research was the Alberta Infant Motor Scale (AIMS). All 30 infants used the antiretroviral drug properly for 42 consecutive days, in accordance with the protocol of the World Health Organization. Results Out of the total number of infants, 27 (90%) had proper motor performance and 3 (10%) presented motor delay, according to the AIMS. Discussion This study demonstrated that only 10% of the assessed group had developmental delay and no relation with environmental variables was detected, such as maternal level of education, social and economic issues, maternal practices, attendance at the day care center, and drug use during pregnancy. It is important to emphasize the necessity of studies with a larger number of participants.

Total Reaction Time Performance of Individuals with Autism after a Virtual Reality Task

Evidence suggests that people with autism perform simple reaction time (RT) tasks differently than typically developing (TD) individuals. The current study examines this possibility by investigating the simple total reaction time (TRT) performance and examined effects of practice on a virtual reality motor task (VRMT) in participants with autism. Twenty-seven participants diagnosed with autism spectrum disorder (ASD) and twenty-seven TD participants completed a TRT test alternated with a VRMT. Significant increases in TRT measures were found postpractice with the VRMT only in the female autistic group. These findings suggest that the VRMT is a promising tool for improving visual RT functioning in autistic individuals.

Verbal and visual stimulation effects on rectus femoris and biceps femoris muscles during isometric and concentric

Background Coactivation may be both desirable (injury prevention) or undesirable (strength measurement). In this context, different styles of muscle strength stimulus have being investigated. In this study we evaluated the effects of verbal and visual stimulation on rectus femoris and biceps femoris muscles contraction during isometric and concentric. Methods We investigated 13 men (age =23.1 ± 3.8 years old; body mass =75.6 ± 9.1 kg; height =1.8 ± 0.07 m). We used the isokinetic dynamometer BIODEX device and an electromyographic (EMG) system. We evaluated the maximum isometric and isokinetic knee extension and flexion at 60°/s. The following conditions were evaluated: without visual nor verbal command (control); verbal command; visual command and; verbal and visual command. In relation to the concentric contraction, the volunteers performed five reciprocal and continuous contractions at 60°/s. With respect to isometric contractions it was made three contractions of five seconds for flexion and extension in a period of one minute. Results We found that the peak torque during isometric flexion was higher in the subjects in the VVC condition (p > 0.05). In relation to muscle coactivation, the subjects presented higher values at the control condition (p > 0.05). Conclusion We suggest that this type of stimulus is effective for the lower limbs.

The motor repertoire in 3- to 5-month old infants with Down syndrome

Background Even though Down syndrome is the most common chromosomal cause of intellectual disability, studies on early development are scarce. Aim To describe movements and postures in 3- to 5-month-old infants with Down syndrome and assess the relation between pre- and perinatal risk factors and the eventual motor performance. Methods and procedures Exploratory study; 47 infants with Down syndrome (26 males, 27 infants born preterm, 22 infants with congenital heart disease) were videoed at 10–19 weeks post-term (median = 14 weeks). We assessed their Motor Optimality Score (MOS) based on postures and movements (including fidgety movements) and compared it to that of 47 infants later diagnosed with cerebral palsy and 47 infants with a normal neurological outcome, matched for gestational and recording ages. Outcomes and results The MOS (median = 13, range 10–28) was significantly lower than in infants with a normal neurological outcome (median = 26), but higher than in infants later diagnosed with cerebral palsy (median = 6). Fourteen infants with Down syndrome showed normal fidgety movements, 13 no fidgety movements, and 20 exaggerated, too fast or too slow fidgety movements. A lack of movements to the midline and several atypical postures were observed. Neither preterm birth nor congenital heart disease was related to aberrant fidgety movements or reduced MOS. Conclusions and implications The heterogeneity in fidgety movements and MOS add to an understanding of the large variability of the early phenotype of Down syndrome. Studies on the predictive values of the early spontaneous motor repertoire, especially for the cognitive outcome, are warranted. What this paper adds The significance of this exploratory study lies in its minute description of the motor repertoire of infants with Down syndrome aged 3–5 months. Thirty percent of infants with Down syndrome showed age-specific normal fidgety movements. The rate of abnormal fidgety movements (large amplitude, high/slow speed) or a lack of fidgety movements was exceedingly high. The motor optimality score of infants with Down syndrome was lower than in infants with normal neurological outcome but higher than in infants who were later diagnosed with cerebral palsy. Neither preterm birth nor congenital heart disease were related to the motor performance at 3–5 months.