Rate of craniometric change following suture release in patients with metopic and sagittal craniosynostosis

OBJECTIVE Craniosynostosis is a congenital disorder resulting from the premature fusion of cranial sutures in the infant skull. This condition results in significant cosmetic deformity and can impede neurodevelopment, if left untreated. Currently, rates of craniometric change following minimally invasive surgery have only been examined for sagittal craniosynostosis. A better understanding of postoperative skull adaptations in other craniosynostosis subtypes is needed to objectively categorize surgical outcomes and guide length of cranial orthosis therapy. METHODS Eleven patients with sagittal and 8 with metopic craniosynostosis treated using endoscopic strip craniectomy and postoperative helmet orthoses were retrospectively reviewed. Using semiautomated image analysis of top-down orthogonal 2D photographs, the following craniometrics were recorded before surgery and at postoperative visits: cephalic index (CI), cranial vault asymmetry index (CVAI), anterior arc angle (AAA), posterior arc angle (PAA), anterior-middle width ratio (AMWR), anterior-posterior width ratio (APWR), left-right height ratio (LRHR), sagittal Hu moment (Sag-Hu), and brachycephaly Hu moment (Brachy-Hu). These craniometrics were then normalized to photograph-based measurements of normocephalic patients and the rates of change between metopic and sagittal craniosynostoses were compared. RESULTS Patients with sagittal craniosynostosis exhibited significantly lower CI, lower PAA, higher AMWR, higher APWR, lower Sag-Hu, and higher Brachy-Hu preoperatively compared to patients with normocephalic craniosynostosis. Patients with metopic craniosynostosis exhibited lower AAA and AMWR preoperatively compared to normocephalic subjects. Sagittal and metopic patients had a rapid initial change in normalized CI or AAA, respectively. Craniometric rates of change that significantly differed between metopic and sagittal patients were found in AAA (p < 0.001), AMWR (p < 0.001), and APWR (p < 0.0001). Metopic patients had a prolonged AAA change with a significantly different rate of change up to 6 months postoperatively (median at 3 months = 0.027 normalized units/day, median at 6 months = 0.017 normalized units/day, and median at > 6 months = 0.007 normalized units/day), while sagittal CI rate of change at these time points was not significantly different. CONCLUSIONS Patients with metopic craniosynostosis have a prolonged rate of change compared to patients with sagittal craniosynostosis and may benefit from longer helmet use and extended postoperative follow-up. Categorizing craniometric changes for other craniosynostosis subtypes will be important for evaluating current treatment guidelines.

Increasing the gradient of energetic cost does not initiate adaptation in human walking

When in a new situation, the nervous system may benefit from adapting its control policy. In determining whether or not to initiate this adaptation, the nervous system may rely on some features of the new situation. Here we tested whether one such feature is salient cost savings. We changed cost saliency by manipulating the gradient of participants' energetic cost landscape during walking. We hypothesized that steeper gradients would cause participants to spontaneously adapt their step frequency to lower costs. To manipulate the gradient, a mechatronic system applied controlled fore-aft forces to the waist of participants as a function of their step frequency as they walked on a treadmill. These forces increased the energetic cost of walking at high step frequencies and reduced it at low step frequencies. We successfully created three cost landscapes of increasing gradients, where the natural variability in participants' step frequency provided cost changes of 3.6% (shallow), 7.2% (intermediate) and 10.2% (steep). Participants did not spontaneously initiate adaptation in response to any of the gradients. Using metronome-guided walking-a previously established protocol for eliciting initiation of adaptation-participants next experienced a step frequency with a lower cost. Participants then adapted by -1.41±0.81 (p=0.007) normalized units away from their originally preferred step frequency obtaining cost savings of 4.80±3.12% That participants would adapt under some conditions, but not in response to steeper cost gradients, suggests that the nervous system does not solely rely on the gradient of energetic cost to initiate adaptation in novel situations.

Sleep deprivation reduces vagal tone during an inspiratory endurance task in humans

Study Objectives Sleep deprivation alters inspiratory endurance by reducing inspiratory motor output. Vagal tone is involved in exercise endurance. This study aimed to investigate the effect of sleep deprivation on vagal tone adaptation in healthy subjects performing an inspiratory effort. Methods Vagal tone was assessed using Heart Rate Variability normalized units of frequency domain component HF (high frequency) before, at the start, and the end of an inspiratory loading trial performed until exhaustion by 16 volunteers after one night of sleep deprivation and one night of normal sleep, where sleep deprivation reduced the inspiratory endurance by half compared to the normal sleep condition (30min vs 60 min). Results At rest, heart rate was similar in sleep deprivation and normal sleep conditions. In normal sleep condition, heart rate increased during inspiratory loading task; this increase was greater in sleep deprivation condition. In normal sleep condition, vagal tone increased at the beginning of the trial. This vagal tone increase was absent in sleep deprivation condition. Conclusions Sleep deprivation abolished vagal tone response to inspiratory load, possibly contributing to a higher heart rate during the trial and to a reduced inspiratory endurance.

Comparison of Heart Rate Variability Before and After a Table Tennis Match

The aim of this study was to compare heart rate variability indices before and after a table tennis match. Sixteen males (21.86 ± 8.34 yr, 1.73 ± 0.08 m, 64.09 ± 13.39 kg and 21.46 ± 4.38 kg·m-2) were evaluated in 21 matches, before and after the match. We observed that in time domain analysis, Mean RR, SDNN, LnRMSSD and pNN50 after match values were significantly lower than before match values (p < 0.01 or p < 0.05), while Mean HR, Min HR and Max HR values were higher (p < 0.01) after than before the match, with no significant differences (p > 0.05) in STD HR. Meanwhile, frequency domain analysis showed LF Power (log), HF Power (log) and HF Power (in normalized units) after match values significantly lower than before match values (p < 0.01 or p < 0.05), while LF/HF value was higher after the match (p < 0.01), with no significant differences (p > 0.05) in LF Power (ms2), LF Power (in normalized units) and HF Power (ms2) values. Non-linear analysis showed SD1 and SD2 POST values significantly lower than PRE values (p < 0.05), while no significant differences were observed in SD2/SD1 value between POST and PRE analysis. As conclusion, due to the physiological strain of the table tennis match, changes were observed in heart rate variability values, suggesting an increase of sympathetic influence and a reduction of the parasympathetic influence.

Contribution of the Renal Nerves to Hypertension in a Rabbit Model of Chronic Kidney Disease

Overactivity of the sympathetic nervous system and high blood pressure are implicated in the development and progression of chronic kidney disease (CKD) and independently predict cardiovascular events in end-stage renal disease. To assess the role of renal nerves, we determined whether renal denervation (RDN) altered the hypertension and sympathoexcitation associated with a rabbit model of CKD. The model involves glomerular layer lesioning and uninephrectomy, resulting in renal function reduced by one-third and diuresis. After 3-week CKD, blood pressure was 13±2 mm Hg higher than at baseline ( P <0.001), and compared with sham control rabbits, renal sympathetic nerve activity was 1.2±0.5 normalized units greater ( P =0.01). The depressor response to ganglion blockade was also +8.0±3 mm Hg greater, but total norepinephrine spillover was 8.7±3.7 ng/min lower (both P <0.05). RDN CKD rabbits only increased blood pressure by 8.0±1.5 mm Hg. Renal sympathetic activity, the response to ganglion blockade and diuresis were similar to sham denervated rabbits (non-CKD). CKD rabbits had intact renal sympathetic baroreflex gain and range, as well as normal sympathetic responses to airjet stress. However, hypoxia-induced sympathoexcitation was reduced by −9±0.4 normalized units. RDN did not alter the sympathetic response to hypoxia or airjet stress. CKD increased oxidative stress markers Nox5 and MCP-1 (monocyte chemoattractant protein-1) in the kidney, but RDN had no effect on these measures. Thus, RDN is an effective treatment for hypertension in this model of CKD without further impairing renal function or altering the normal sympathetic reflex responses to various environmental stimuli.

Important differences in cardiovascular autonomic control of hypertensive middle-aged women and men – a critical appraisal

BackgroundNormotensive women before menopause showed a vagal predominance of cardiac autonomic modulation, while age-matched men showed a sympathetic modulation predominance. However, some women develop systemic arterial hypertension (SAH) even with preserved ovarian function. Our hypothesis is that these women may have cardiovascular autonomic parameters like those of hypertensive men, even when subjected to pharmacological treatment. We aim to investigate the cardiovascular autonomic modulation balance and baroreflex sensitivity (BRS) in hypertensive women with preserved ovarian function and age-matched men.MethodsOne hundred volunteers between 18 and 45 years of age, were assigned to two groups of fifty: Hypertensive group, with a SAH history for at least 6 months (25 men and 25 women) treated with monotherapy (losartan, 25-50mg/kg) and normotensive group (25 men and 25 women). Anthropometric, hemodynamic, metabolic, and autonomic cardiovascular assessments were performed focusing: BRS, autonomic modulation of heart rate variability (HRV) and blood pressure variability (BPV).ResultsThe results showed that HRV analysis, women showed higher values ​​of HF oscillations in absolute and normalized units, and lower values ​​of LF in normalized units and LF/HF ratio compared to men. When normotensive and hypertensive groups were compared, hypertensive groups showed lower values ​​of total variance, LF and HF bands in absolute units. There were similar in BPV. However, hypertensive groups showed lower BRS values when compared to normotensive group.ConclusionThe results indicate that hypertensive groups even with blood pressure controlled through pharmacological treatment, continued to have reduced HRV than normotensive, and hypertensive women have minor cardiovascular autonomic impairment than men.

Depression is closely associated with discoordination between the heart rate variability and physical acceleration in free-moving older women

Background We investigated the relationship between psychological distress and the coordination of heart rate variability (HRV) and physical acceleration (PA) during free-moving days in women. Methods Ninety-five adult women were divided into younger and older groups. The younger group comprised 50 women (22–59 years), and the older group comprised 45 women (≥ 60 years). HRV and PA data were simultaneously obtained every minute for 24 h during the free-moving day. The ratios of low frequency/high frequency and high frequency in normalized units were used as HRV indices. We defined %Lag0 as the % frequency of the lag = 0 min between HRV and PA in 1 h. The General Health Questionnaire 28 (GHQ28) was used to evaluate the effects of psychological distress and depression. Results In the hour before the night’s sleep, %Lag0 was significantly lower in older women with depression (GHQ28 subscale D) than in older women without depression (p < 0.05). However, no significant difference between %Lag0 and depression status was observed in the hour after waking in older women. Conclusions The results suggest that impairments in coordination between HRV and PA are associated with depression in older women, particularly in the hour before a night’s sleep on free-moving days.

MODULATION OF AUTONOMIC NERVOUS SYSTEM ASSESSED THROUGH HEART RATE VARIABILITY BY INTEGRATED AMRITA MEDITATION TECHNIQUE IN TYPE 2 DIABETIC SUBJECTS – A PILOT STUDY

Objective: This study aims in understanding the effects of Integrated Amrita Meditation (IAM), a type of mindfulness meditation, on the autonomic balance of type 2 diabetic patients through assessment of heart rate variability (HRV). Methods: After the initial screening of 30 type 2 diabetic subjects, 10 type 2 diabetic subjects between the age group of 30 and 65 years were randomized into two groups, diabetic test (n=5) and diabetic control group (n=5). Diabetic test group practiced IAM technique under the guidance of a trained practitioner. Both the groups continued the same dietary pattern and medications during the 6-month study period. HRV was taken for all subjects at baseline and after 6 months. In our study, we have focused on the power spectral analysis of HRV which include normalized units of high frequency (nHF), low frequency (nLF), and low frequency-high frequency ratio (LF/HF ratio). Results: Mean percentage change in nHF, nLF, and LFHF ratio showed significant changes in between-group comparison (p<0.05). Normalized units of HF increased (p=0.049) while LF (p=0.036) and LFHF ratio (p=0.024) decreased significantly within test group after 6 months of IAM practice suggesting the potential of IAM in improving the parasympathetic tone, thereby tuning the mind and body to calm down during stress. Conclusion: Our study has shown demonstrable improvement in autonomic function which reflects reduced stress after the practice of IAM in diabetic patients.

Increasing the gradient of energetic cost does not initiate adaptation in human walking

When in a new situation, the nervous system may benefit from adapting its control policy. In determining whether or not to initiate this adaptation, the nervous system may rely on some features of the new situation. Here we tested whether one such feature is salient cost savings. We changed cost saliency by manipulating the gradient of participants’ energetic cost landscape during walking. We hypothesized that steeper gradients would cause participants to spontaneously adapt their step frequency to lower costs. To manipulate the gradient, a mechatronic system applied controlled fore-aft forces to the waist of participants as a function of their step frequency as they walked on a treadmill. These forces increased the energetic cost of walking at high step frequencies and reduced it at low step frequencies. We successfully created three cost landscapes of increasing gradients, where the natural variability in participants’ step frequency provided cost changes of 3.6% (shallow), 7.2% (intermediate) and 10.2% (steep). Participants did not spontaneously initiate adaptation in response to any of the gradients. Using metronome-guided walking— a previously established protocol for eliciting initiation of adaptation—participants next experienced a step frequency with a lower cost. Participants then adapted by −1.41±0.81 (p=0.007) normalized units away from their originally preferred step frequency obtaining cost savings of 4.80±3.12%. That participants would adapt under some conditions, but not in response to steeper cost gradients, suggests that the nervous system does not solely rely on the gradient of energetic cost to initiate adaptation in novel situations.

GROUP ALGEBRAS WHOSE UNIT GROUP IS LOCALLY NILPOTENT

We present a complete list of groups $G$ and fields $F$ for which: (i) the group of normalized units $V(FG)$ of the group algebra $FG$ is locally nilpotent; (ii) the set of nontrivial nilpotent elements of $FG$ is finite and nonempty, and $V(FG)$ is an Engel group.