Changes in oxygen partial pressure of brain tissue in an animal model of obstructive apnea

Background: Cognitive impairment is one of the main consequences of obstructive sleep apnea (OSA) and is usually attributed in part to the oxidative stress caused by intermittent hypoxia in cerebral tissues. The presence of oxygen-reactive species in the brain tissue should be produced by the deoxygenation-reoxygenation cycles which occur at tissue level during recurrent apneic events. However, how changes in arterial blood oxygen saturation (SpO2) during repetitive apneas translate into oxygen partial pressure (PtO2) in brain tissue has not been studied. The objective of this study was to assess whether brain tissue is partially protected from intermittently occurring interruption of O2 supply during recurrent swings in arterial SpO2 in an animal model of OSA. Methods: Twenty-four male Sprague-Dawley rats (300-350 g) were used. Sixteen rats were anesthetized and noninvasively subjected to recurrent obstructive apneas: 60 apneas/h, 15 s each, for 1 h. A control group of 8 rats was instrumented but not subjected to obstructive apneas. PtO2 in the cerebral cortex was measured using a fastresponse oxygen microelectrode. SpO2 was measured by pulse oximetry. The time dependence of arterial SpO2 and brain tissue PtO2 was carried out by Friedman repeated measures ANOVA. Results: Arterial SpO2 showed a stable periodic pattern (no significant changes in maximum [95.5 ± 0.5%; m ± SE] and minimum values [83.9 ± 1.3%]). By contrast, brain tissue PtO2 exhibited a different pattern from that of arterial SpO2. The minimum cerebral cortex PtO2 computed during the first apnea (29.6 ± 2.4 mmHg) was significantly lower than baseline PtO2 (39.7 ± 2.9 mmHg; p = 0.011). In contrast to SpO2, the minimum and maximum values of PtO2 gradually increased (p < 0.001) over the course of the 60 min studied. After 60 min, the maximum (51.9 ± 3.9 mmHg) and minimum (43.7 ± 3.8 mmHg) values of PtO2 were significantly greater relative to baseline and the first apnea dip, respectively. Conclusions: These data suggest that the cerebral cortex is partially protected from intermittently occurring interruption of O2 supply induced by obstructive apneas mimicking OSA

Parenting Styles: A Closer Look at a Well-Known Concept

Although parenting styles constitute a well-known concept in parenting research, two issues have largely been overlooked in existing studies. In particular, the psychological control dimension has rarely been explicitly modelled and there is limited insight into joint parenting styles that simultaneously characterize maternal and paternal practices and their impact on child development. Using data from a sample of 600 Flemish families raising an 8-to-10 year old child, we identified naturally occurring joint parenting styles. A cluster analysis based on two parenting dimensions (parental support and behavioral control) revealed four congruent parenting styles: an authoritative, positive authoritative, authoritarian and uninvolved parenting style. A subsequent cluster analysis comprising three parenting dimensions (parental support, behavioral and psychological control) yielded similar cluster profiles for the congruent (positive) authoritative and authoritarian parenting styles, while the fourth parenting style was relabeled as a congruent intrusive parenting style. ANOVAs demonstrated that having (positive) authoritative parents associated with the most favorable outcomes, while having authoritarian parents coincided with the least favorable outcomes. Although less pronounced than for the authoritarian style, having intrusive parents also associated with poorer child outcomes. Results demonstrated that accounting for parental psychological control did not yield additional parenting styles, but enhanced our understanding of the pattern among the three parenting dimensions within each parenting style and their association with child outcomes. More similarities than dissimilarities in the parenting of both parents emerged, although adding psychological control slightly enlarged the differences between the scores of mothers and fathers

Hyperoxia attenuates muscle sympathetic nerve activity following isocapnic hypoxia in humans

Hypoxia may sensitize the carotid chemoreceptors, resulting in a sustained elevation of muscle sympathetic nerve activity (MSNA) that outlasts the hypoxic stimulus. To test this hypothesis, we determined the effect of carotid body inhibition on the sustained elevation of MSNA following isocapnic hypoxia in humans. Seven healthy subjects (5 male, 2 female) breathed 100% O2 (hyperoxia) for 1 min before (2 interventions) and after (2–3 interventions) 20 min of isocapnic hypoxia (80% arterial oxyhemoglobin saturation). MSNA was continuously recorded from the common peroneal nerve with microneurography. There was no effect of hyperoxia on MSNA before exposure to isocapnic hypoxia. During the isocapnic hypoxia exposure, there was an increase in minute ventilation and heart rate that subsided once hypoxia was terminated. In contrast, there was an increase in MSNA burst frequency that persisted for ∼25 min after cessation of the stimulus. Hyperoxia resulted in a transient reduction in MSNA burst frequency of 28% (P < 0.05), 15% (P < 0.05), and 9% (P > 0.05) in the three posthypoxia interventions, respectively. Our results suggest that input from the carotid chemoreceptors is obligatory for the sustained elevation of MSNA initiated by chemoreflex stimulation. We attribute the decrease in MSNA to a transient hyperoxia-induced attenuation of carotid chemoreceptor sensitivity

Using consumer input to tailor evidence-based parenting interventions to the needs of grandparents

Grandparents provide a significant amount of child care to their grandchildren. However, there is limited research investigating whether grandparents would view a parenting program developed specifically for them as useful. Our study adopted a consumer focused perspective to program design and examined the challenges encountered by grandparents in their role as an informal child care provider. Focus groups were conducted with fourteen grandparents (11 females, 3 males) aged 45-76 years (M = 60.14) the majority of whom provided 11-20 h of care per week to their grandchild. A thematic analysis indicated that grandparents have difficulty managing the relationship with the parents and remembering effective parenting strategies. In addition, grandparents also indicated wanting further strategies to cope with the stressors associated with the role, particularly surrounding feelings of frustration and guilt. These results suggest that grandparents could benefit from a parenting program and this paper argues that an existing evidence-based parenting program should be modified. In terms of implications for program design the inclusion of a module centered on improving grandparent-parent communication and partner support may buffer potential conflict and tension that can arise in co-parenting situations