Publications by authors named "Darby Jack"

Article Synopsis
  • The Ghana Randomized Air Pollution and Health Study (GRAPHS) analyzed the impact of daily maximum shaded wet bulb globe temperature (WBGTmax) and heat index (HImax) on aspects like birth weight and gestational age in pregnant individuals from 2013 to 2015 in Ghana.
  • Results indicated that higher WBGTmax in specific trimesters affected newborn characteristics differently, with higher temperatures linked to increased head circumference but adverse effects on birth weight and length, highlighting the importance of monitoring temperature variations during pregnancy.
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Programming effects of maternal undernutrition on fetal metabolic and cardiovascular systems are well elucidated, yet a detailed characterization of maternal haemodynamics is not available. This study used comprehensive cardiovascular magnetic resonance (CMR) imaging to quantify maternal haemodynamics after 29 days (111-140 days) of late-gestation undernutrition (LGUN) in pregnant sheep. Control ewes received 100% of metabolizable energy requirements (MERs, n = 15), whereas LGUN ewes were globally nutrient restricted to 50% MER (n = 18), with a subset of fetuses undergoing continuous glucose infusion (LGUN + G, n = 6/18).

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Maternal asthma is associated with increased rates of neonatal lung disease, and fetuses from asthmatic ewes have fewer surfactant-producing cells and lower surfactant-protein B gene (SFTPB) expression than controls. Antenatal betamethasone increases lung surfactant production in preterm babies, and we therefore tested this therapy in experimental maternal asthma. Ewes were sensitised to house dust mite allergen, and an asthmatic phenotype induced by fortnightly allergen lung challenges; controls received saline.

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Introduction: Household energy transitions have the potential to reduce the burden of several health outcomes but have narrowly focused on those mediated by reduced exposure to air pollution, despite concerns about the burden of injury outcomes. Here, we aimed to describe the country-level incidence of severe cooking-related burns in Ghana and identify household-level risk factors for adults and children.

Methods: We conducted a national household energy use survey including 7389 households across 370 enumeration areas in Ghana in 2020.

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The consumption of high fat-high energy diets (HF-HEDs) continues to rise worldwide and parallels the rise in maternal obesity (MO) that predisposes offspring to cardiometabolic disorders. Although the underlying mechanisms are unclear, thyroid hormones (TH) modulate cardiac maturation in utero. Therefore, we aimed to determine the impact of a high fat-high energy diet (HF-HED) on the hormonal, metabolic and contractility profile of the non-human primate (NHP) fetal heart.

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Background: Cardiac MRI feature tracking (FT) allows objective assessment of segmental left ventricular (LV) function following a myocardial infarction (MI), but its utilization in sheep, where interventions can be tested, is lacking.

Purpose: To apply and validate FT in a sheep model of MI and describe post-MI LV remodeling.

Study Type: Animal model, longitudinal.

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Introduction: The fetal haemodynamic response to acute episodes of hypoxaemia are well characterised. However, how these responses change when the hypoxaemia becomes more chronic in nature such as that associated with fetal growth restriction (FGR), is less well understood. Herein, we utilised a combination of clinically relevant MRI techniques to comprehensively characterize and differentiate the haemodynamic responses occurring during acute and chronic periods of fetal hypoxaemia.

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Objectives: We evaluated fetal cardiovascular physiology and mode of cardiac failure in premature miniature piglets on a pumped artificial placenta (AP) circuit.

Methods: Fetal pigs were cannulated via the umbilical vessels and transitioned to an AP circuit composed of a centrifugal pump and neonatal oxygenator and maintained in a fluid-filled biobag. Echocardiographic studies were conducted to measure ventricular function, umbilical blood flow, and fluid status.

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Article Synopsis
  • Approximately 3 billion people, mainly in low- and middle-income countries, use unclean fuels for everyday energy needs, leading to significant health issues like pneumonia and chronic lung disease.
  • A multidisciplinary group conducted a review of recent trials on clean cooking interventions to combat household air pollution (HAP) and reached 14 consensus recommendations for policy makers and practitioners.
  • While some interventions showed reduced exposure to HAP, there was no clear agreement on their effectiveness in improving health outcomes, highlighting the need for continued research and collaboration with policymakers.
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Background: The association between prenatal household air pollution (HAP) exposure and childhood blood pressure (BP) is unknown.

Objective: Within the Ghana Randomized Air Pollution and Health Study (GRAPHS) we examined time-varying associations between ) maternal prenatal and ) first-year-of-life HAP exposure with BP at 4 years of age and, separately, whether a stove intervention delivered prenatally and continued through the first year of life could improve BP at 4 years of age.

Methods: GRAPHS was a cluster-randomized cookstove intervention trial wherein pregnant women were randomized to one of two stove interventions: ) a liquefied petroleum gas (LPG) stove or improved biomass stove, or ) control (open fire cooking).

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Fetal lungs have fewer and smaller arteries with higher pulmonary vascular resistance (PVR) than a newborn. As gestation advances, the pulmonary circulation becomes more sensitive to changes in pulmonary arterial oxygen tension, which prepares them for the dramatic drop in PVR and increase in pulmonary blood flow (PBF) that occur when the baby takes its first few breaths of air, thus driving the transition from fetal to postnatal circulation. Dynamic and intricate regulatory mechanisms control PBF throughout development and are essential in supporting gas exchange after birth.

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Objective: To describe the mortality risks by fine strata of gestational age and birthweight among 230 679 live births in nine low- and middle-income countries (LMICs) from 2000 to 2017.

Design: Descriptive multi-country secondary data analysis.

Setting: Nine LMICs in sub-Saharan Africa, Southern and Eastern Asia, and Latin America.

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The impact of a household air pollution (HAP) stove intervention on child lung function has been poorly described. To assess the effect of a HAP stove intervention for infants prenatally to age 1 on, and exposure-response associations with, lung function at child age 4. The Ghana Randomized Air Pollution and Health Study randomized pregnant women to liquefied petroleum gas (LPG), improved biomass, or open-fire (control) stove conditions through child age 1.

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Article Synopsis
  • Babies with fetal growth restriction (FGR) face increased risk of cardiometabolic diseases, as FGR negatively impacts heart growth, metabolism, and function due to reduced nutrient supply during development.
  • Using a sheep model, researchers found that key proteins and genes involved in fatty acid transport and metabolism in the heart were significantly reduced in FGR fetuses, indicating impaired cardiac metabolic function.
  • Despite the diminished metabolic capacity and lower mitochondrial numbers in the hearts of FGR fetuses, these changes did not correlate with heart output, suggesting that altered metabolism may lead to poor cardiac health later in life for affected individuals.
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Background: Personal exposure to fine particulate matter (PM) from household air pollution is well-documented in sub-Saharan Africa, but spatiotemporal patterns of exposure are poorly characterized.

Objective: We used paired GPS and personal PM data to evaluate changes in exposure across location-time environments (e.g.

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A major part of Ghana's current household energy policy is focused on using a branded cylinder recirculation model (BCRM) to promote the safe use of Liquefied Petroleum Gas (LPG) for primary cooking. The implementation of the BCRM is expected to increase LPG adoption by households to the announced policy goal of 50% of the population by 2030. We investigated the impact of the COVID-19 pandemic on the implementation of the BCRM, availability, and household use of cleaner fuels.

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Household electrification is thought to be an important part of a carbon-neutral future and could also have additional benefits to adopting households such as improved air quality. However, the effectiveness of specific electrification policies in reducing total emissions and boosting household livelihoods remains a crucial open question in both developed and developing countries. We investigated a transition of more than 750,000 households from gas to electric cookstoves-one of the most popular residential electrification strategies-in Ecuador following a program that promoted induction stoves and assessed its impacts on electricity consumption, greenhouse gas emissions, and health.

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Aims: To evaluate the effects of fetal glucose infusion in late gestation on the mRNA expression and protein abundance of molecules involved in the regulation of cardiac growth and metabolism.

Main Methods: Either saline or glucose was infused into fetal sheep from 130 to 140 days (d) gestation (term, 150 d). At 140 d gestation, left ventricle tissue samples were collected.

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Particulate matter air pollution is a leading cause of global mortality, particularly in Asia and Africa. Addressing the high and wide-ranging air pollution levels requires ambient monitoring, but many low- and middle-income countries (LMICs) remain scarcely monitored. To address these data gaps, recent studies have utilized low-cost sensors.

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Background: Prenatal household air pollution impairs birth weight and increases pneumonia risk however time-varying associations have not been elucidated and may have implications for the timing of public health interventions.

Methods: The Ghana Randomized Air Pollution and Health Study (GRAPHS) enrolled 1,414 pregnant women from Kintampo, Ghana and measured personal carbon monoxide (CO) exposure four times over pregnancy. Birth weight was measured within 72-hours of birth.

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Article Synopsis
  • Babies born growth-restricted face higher risks for poor health outcomes both in the short and long term, and current treatments aren't effective in mitigating these risks.
  • Maternal treatment with resveratrol (RSV) may improve fetal conditions by increasing blood flow and oxygenation, but there are concerns that high polyphenol diets could negatively affect fetal blood circulation.
  • MRI studies showed that acute RSV exposure did not change fetal blood pressure, heart rate, or oxygen delivery, supporting its potential safety as a treatment for fetal growth restriction.
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Over recent decades, a variety of advanced imaging techniques for assessing cardiovascular physiology and cardiac function in adults and children have been applied in the fetus. In many cases, technical development has been required to allow feasibility in the fetus, while an appreciation of the unique physiology of the fetal circulation is required for proper interpretation of the findings. This review will focus on recent advances in fetal echocardiography and cardiovascular magnetic resonance (CMR), providing examples of their application in research and clinical settings.

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