Effect of Hyperventilation on Periodic Repolarization Dynamics

Heart and lung functions are closely connected, and the interaction is mediated by the autonomic nervous system. Hyperventilation has been demonstrated to especially activate its sympathetic branch. However, there is still a lack of methods to assess autonomic activity within this cardiorespiratory coupling. Periodic repolarization dynamics (PRD) is an ECG-based biomarker mirroring the effect of efferent cardiac sympathetic activity on the ventricular myocardium. Its calculation is based on beat-to-beat variations of the T wave vector (dT degrees). In the present study, we investigated the effects of a standardized hyperventilation maneuver on changes of PRD and its underlyingdT degrees signal in 11 healthy subjects. In response to hyperventilation,dT degrees revealed a characteristic pattern and normalizeddT degrees values increased significantly compared to baseline [0.063 (IQR 0.032) vs. 0.376 (IQR 0.093),p< 0.001] and recovery [0.082 (IQR 0.029) vs. 0.376 (IQR 0.093),p< 0.001]. During recovery,dT degrees remained on a higher level compared to baseline (p= 0.019). When calculating PRD, we found significantly increased PRD values after hyperventilation compared to baseline [3.30 (IQR 2.29) deg(2)vs. 2.76 (IQR 1.43) deg(2),p= 0.018]. Linear regression analysis revealed that the increase in PRD level was independent of heart rate (p= 0.63). Our pilot data provide further insights in the effect of hyperventilation on sympathetic activity associated repolarization instability

FMRP associates with cytoplasmic granules at the onset of meiosis in the human oocyte

Germ cell development and primordial follicle formation during fetal life is critical in establishing the pool of oocytes that subsequently determines the reproductive lifespan of women. Fragile X-associated primary ovarian insufficiency (FXPOI) is caused by inheritance of the FMR1 premutation allele and approximately 20% of women with the premutation allele develop ovarian dysfunction and premature ovarian insufficiency. However, the underlying disease mechanism remains obscure, and a potential role of FMRP in human ovarian development has not been explored. We have characterised the expression of FMR1 and FMRP in the human fetal ovary at the time of germ cell entry into meiosis through to primordial follicle formation. FMRP expression is exclusively in germ cells in the human fetal ovary. Increased FMRP expression in germ cells coincides with the loss of pluripotency-associated protein expression, and entry into meiosis is associated with FMRP granulation. In addition, we have uncovered FMRP association with components of P-bodies and stress granules, suggesting it may have a role in mRNA metabolism at the time of onset of meiosis. Therefore, this data support the hypothesis that FMRP plays a role regulating mRNAs during pivotal maturational processes in fetal germ cells, and ovarian dysfunction resulting from FMR1 premutation may have its origins during these stages of oocyte development

Defining traumatic events: An examination of the A criteria

https://nsuworks.nova.edu/cps_facbooks/1391/thumbnail.jp

Selective stimulation of pig radial nerve: comparison of 12-polar and 18-polar cuff electrodes

Aiming at the development of an implantable neuroprosthesis for restoration of hand function in tetraplegic patients (C5/C6), we examined and compared the stimulation performance of two different neural electrode designs. Our studies on the radial nerve of adult pigs proved the feasibility of selective control of different forearm muscles by using only one multichannel nerve cuff electrode. The results gained by applying a 12-polar cuff electrode design were poor, while the potential of an 18-polar design was very encouraging