A control-based observer approach for estimating energy intake during pregnancy

Gestational weight gain outside of Institute of Medicine guidelines poses a risk to both the mother and her unborn child. Behavioral interventions such as Healthy Mom Zone (HMZ) that aim to regulate gestational weight gain require self-monitoring of energy intake, which is often significantly under-reported by participants. This paper describes the use of a control systems approach for energy intake estimation during pregnancy. It relies on an energy balance model that predicts gestational weight based on physical activity and energy intake, the latter treated as an unmeasured disturbance. Two control-based observer formulations relying on Internal Model Control and Model Predictive Control, respectively, are presented in this paper, first for a hypothetical participant, then on data collected from four HMZ participants. Results demonstrate the effectiveness of the method, with generally best results obtained when estimating energy intake over a weekly time period.

Clinical trial management: a profession in crisis?

Clinical trial managers play a vital role in the design and conduct of clinical trials in the UK. There is a current recruitment and retention crisis for this specialist role due to a complex set of factors, most likely to have come to a head due to the COVID-19 pandemic. Academic clinical trial units and departments are struggling to recruit trial managers to vacant positions, and multiple influences are affecting the retention of this highly skilled workforce. Without tackling this issue, we face major challenges in the delivery on the Department of Health and Social Care's Future of UK Clinical Research Delivery implementation plan. This article, led by a leading network of and for UK Trial Managers, presents some of the issues and ways in which national stakeholders may be able to address this.

Teaching families to manage intake of candy in the home: Results from a feasibility study using multiphase optimization strategy (MOST)

BACKGROUND

Excess intake of desserts/sweets high in added sugars, such as candy, is linked with greater obesity risk. Parents often limit their childrens' intake of these sweet foods using controlling feeding practices, such as restriction; yet, restrictive feeding practices are counterproductive for childrens' self-regulation of energy intake.

OBJECTIVE

This study developed a family-based behavioural intervention that taught parents alternatives to restrictive feeding practices and encouraged children to consume candy in moderation.

METHODS

Using the multiphase optimization strategy (MOST), parent-child dyads (N = 37) were randomized into one of eight conditions that included a combination of intervention components delivered over 4 weeks: home supply, parent shared decision making, child mindfulness and child attention control strategies.

RESULTS

Retention rate at follow-up was high (95%). Among parents who received parent shared decision making, 86.4% reported the structured-based candy routine they set with their child was easy to follow. Most children reported child mindfulness (95%) and attention control (89.5%) strategies were easy to play. Children recalled 4.1 ± 1.8 of the six mindfulness strategies and 2.7 ± 1.6 of the five attention control strategies at follow-up. Eating in the absence of hunger tended to be lower for children who received parent shared decision making and child mindfulness components.

CONCLUSION

This intervention was feasible and well-implemented in the home environment. Findings will inform future, larger interventions designed to test similar strategies on childrens; eating behaviours and self-regulation.

Feasibility of enhancing well-child visits with family nutrition and physical activity risk assessment on body mass index

OBJECTIVE

Integration of behavioural risk assessment into well-child visits is recommended by clinical guidelines, but its feasibility and impact is unknown.

METHODS

A quasi-experimental study evaluated the feasibility and effectiveness of risk assessment on body mass index (BMI) at 1-year follow-up. Children with assessments (intervention) were compared with those who did not complete assessments (non-respondent) and those who received standard care (non-exposed).

RESULTS

Analyses included 10,647 children aged 2-9 years (2,724 intervention, 3,324 non-respondent and 4,599 non-exposed). Forty-five per cent of parents completed the assessments. Intervention and non-respondent groups differed in change in BMI z-score at 1 year by -0.05 (confidence interval [CI]: -0.08, -0.02; P = 0.0013); no difference was observed with non-exposed children. The intervention group had a smaller increase in BMI z-score (0.07 ± 0.63) than non-respondent group (0.13 ± 0.63). For children with normal weight at baseline, intervention versus non-respondent groups differed in BMI z-score change by -0.06 (CI: -0.10, -0.02; P = 0.0025). However, children with overweight at baseline in the intervention versus the non-exposed group differed in BMI z-score change (0.07 [CI: 0.02, 0.14]; P = 0.016). When analysed by age, results were similar for 2- to 5-year-olds, but no differences were found for 6- to 9-year-olds.

CONCLUSION

Automating risk assessment in paediatric care is feasible and effective in promoting healthy weight among preschool but not older children.

Alternatives to restrictive feeding practices to promote self-regulation in childhood: a developmental perspective

Intake of energy-dense snack foods is high among US children. Although the use of restrictive feeding practices has been shown to be counterproductive, there is very limited evidence for effective alternatives to restriction that help children moderate their intake of these foods and that facilitate the development of self-regulation in childhood. The developmental literature on parenting and child outcomes may provide insights into alternatives to restrictive feeding practices. This review paper uses a model of parental control from the child development and parenting literatures to (i) operationally define restrictive feeding practices; (ii) summarize current evidence for antecedents and effects of parental restriction use on children's eating behaviours and weight status, and (iii) highlight alternative feeding practices that may facilitate the development of children's self-regulation and moderate children's intake of palatable snack foods. We also discuss recent empirical evidence highlighting the role of child temperament and food motivation related behaviours as factors that prompt parents to use restrictive feeding practices and, yet, may increase children's dysregulated intake of forbidden foods.

Identification of roles for the SNARE-associated protein, SNAP29, in mouse platelets

Platelets are critical for maintaining vascular hemostasis, but also play a major role in the formation of occlusive cardiovascular and cerebrovascular thrombi under disease conditions. Secretion of platelet alpha and dense granules is a requirement for efficient thrombus formation. Understanding and targeting the mechanisms of secretion is important to aid the development of effective antithrombotics. SNAP29 is a tSNARE found in platelets, but whose role has not been defined. Using a platelet-specific SNAP29 knockout mouse model, we assessed the role of SNAP29 in platelet secretion and function under standardized conditions and also in in vitro and in vivo thrombosis. The data showed no major defects in SNAP29-null platelets, but revealed a minor defect in α-granule secretion and a significant increase in embolization rate of thrombi in vivo. These data suggest that SNAP29 contributes to the regulation of platelet α-granule secretion and thrombus stability, possibly partially masked by functional redundancy with other tSNAREs, such as SNAP23.

Birth stories: a way of knowing in childbirth education

Birth stories have a lasting impact on expectant mothers. The purpose of this paper is to recognize the influence of birth stories as a key component of informal communication of knowledge about childbirth for expectant mothers. The review of literature and research is related to childbirth education, anthropological thinking, and applied learning theory with foundational concepts from Vygotsky, Bruner, and Bandura. Implications for childbirth educators are included.

Protective effects of low and high doses of cyclosporin A against reoxygenation injury in isolated rat cardiomyocytes are associated with differential effects on mitochondrial calcium levels

In this study we aimed to determine the concentration range of cyclosporin A (CsA) which was effective in protecting against reoxygenation injury in isolated cardiomyocytes, and its effects on intramitochondrial free calcium levels ([Ca2+]m). We also determined whether a high [CsA] had any deleterious effect on normal myocyte function. Isolated adult rat ventricular myocytes were placed in a chamber on the stage of a fluorescence microscope for induction of hypoxia. [Ca2+]m was determined from indo-1/am loaded cells where the cytosolic fluorescence signal had been quenched by superfusion with Mn2+. Cell length was measured using an edge-tracking device. Upon induction of hypoxia, control cells underwent rigor-contracture in 37 +/- 1 min (n = 99) (T1); CsA had no effect on T1. The percentage of control cells which recovered upon reoxygenation depended on the time spent in rigor (T2). With a T2 of 21-30 min, only 36% of control cells recovered compared with 90% and 78% of cells treated with 0.2 microM and 1 microM CsA respectively. After 40 min in rigor, [Ca2+]m was 280 +/- 60 nM in control-recovered cells (50% of cells) and 543 +/- 172 nM and 153 +/- 26 nM in cells treated with 0.2 and 1 microM CsA, respectively (all CsA treated cells recovered). In normoxic studies, CsA had no effect on cell contractility or [Ca2+]m upon rapid pacing, even in presence of an elevated external [Ca2+]. In conclusion, both low and high [CsA] protected against reoxygenation injury to cardiomyocytes despite having opposing effects on [Ca2+]m, suggesting more than one mechanism of action. CsA had no effect on either cell contractility or [Ca2+]m in normoxic cells.

Mitochondrial calcium transporting pathways during hypoxia and reoxygenation in single rat cardiomyocytes

OBJECTIVE

Mitochondrial [Ca2+] ([Ca2+]m) rises in parallel with cytosolic [Ca2+] ([Ca2+]c) following ATP-depletion rigor contracture induced by hypoxia in isolated cardiomyocytes. We investigated the pathways involved in the hypoxia induced changes in [Ca2+]m by using known inhibitors of mitochondrial Ca2+ transport, namely ruthenium red, an inhibitor of the Ca2+ uniporter (the normal influx route) and clonazepam, an inhibitor of Na+/Ca2+ exchange, (the normal efflux route).

METHODS

[Ca2+]m was determined from indo-1/am loaded rat myocytes where the cytosolic fluorescence signal had been quenched by superfusion with Mn2+. [Ca2+]c was measured by loading myocytes with indo-1 pentapotassium salt during the isolation procedure. Cells were placed in a specially developed chamber for induction of hypoxia and reoxygenated 40 min after rigor development.

RESULTS

50% of control cells hypercontracted upon reoxygenation; this correlated with a [Ca2+]m or [Ca2+]c higher than approximately 350 nM at the end of rigor. Clonazepam completely abolished the rigor-induced rise in [Ca2+]m but not [Ca2+]c. On reoxygenation [Ca2+]m increased over the first 5 min and remained elevated whereas [Ca2+]c fell. In the presence of ruthenium red a dramatic increase in [Ca2+]m occurred 5-10 min after rigor development (the indo-1 fluorescence signal was saturated); [Ca2+]c also increased but to a lesser extent. On reoxygenation, [Ca2+]m fell rapidly even though cells hypercontracted and [Ca2+]c remained elevated.

CONCLUSIONS

During hypoxia following rigor development Ca2+ uptake into mitochondria occurs largely via the Na+/Ca2+ exchanger rather than the Ca2+ uniporter whereas on reoxygenation the transporters resume their normal directionality.