Abstract Creatine is a metabolite involved in cellular energy homeostasis. In this study, we examined placental creatine content, and expression of the enzymes required for creatine synthesis, transport and the creatine kinase reaction, in pregnancies complicated by low birthweight. We studied first trimester chorionic villus biopsies (CVBs) of small for gestational age (SGA) and appropriately grown infants (AGA), along with third trimester placental samples from fetal growth restricted (FGR) and healthy gestation-matched controls. Placental creatine and creatine precursor (guanidinoacetate—GAA) levels were measured. Maternal and cord serum from control and FGR pregnancies were also analyzed for creatine concentration. mRNA expression of the creatine transporter (SLC6A8); synthesizing enzymes arginine:glycine aminotransferase (GATM) and guanidinoacetate methyltransferase (GAMT); mitochondrial (mtCK) and cytosolic (BBCK) creatine kinases; and amino acid transporters (SLC7A1 & SLC7A2) was assessed in both CVBs and placental samples. Protein levels of AGAT (arginine:glycine aminotransferase), GAMT, mtCK and BBCK were also measured in placental samples. Key findings; total creatine content of the third trimester FGR placentae was 43% higher than controls. The increased creatine content of placental tissue was not reflected in maternal or fetal serum from FGR pregnancies. Tissue concentrations of GAA were lower in the third trimester FGR placentae compared to controls, with lower GATM and GAMT mRNA expression also observed. No differences in the mRNA expression of GATM, GAMT or SLC6A8 were observed between CVBs from SGA and AGA pregnancies. These results suggest placental creatine metabolism in FGR pregnancies is altered in late gestation. The relevance of these changes on placental bioenergetics should be the focus of future investigations.
Blood flow restriction (BFR) exercise is seen as a potential alternative to traditional training methods, and evidence suggests this is being used with both healthy and clinical populations worldwide. Although the efficacy of the technique regarding muscular adaptations is well known, the safety of its use has been questioned. The purpose of this review was: (i) provide an overview of the known reported side-effects while using BFR exercise; (ii) highlight risks associated with the cardiovascular system, and; (iii) suggest recommendations to minimize risk of complications in both healthy and clinical populations. Overall, reported side-effects include perceptual type responses (ie, fainting, numbness, pain, and discomfort), delayed onset muscle soreness, and muscle damage. There may be heightened risk to the cardiovascular system, in particular increased blood pressure responses, thrombolytic events, and damage to the vasculature. However, while these may be of some concern there is no evidence to suggest that BFR exercise elevates the risk of complications any more than traditional exercise modes. Several modifiable extrinsic factors for risk minimization include selecting the appropriate BFR pressure and cuff width, as well as completion of a preexercise safety standard questionnaire to determine any contraindications to BFR or indeed the prescribed exercise. On the basis of the available evidence, we are confident that the side-effects of using BFR are minimal, and further minimized by the use of an appropriate method of application in the hands of a trained practitioner.
ABSTRACT Interstitial lung disease (ILD) is a disabling group of chronic lung conditions comprising over 200 different disease entities that are typically associated with interstitial inflammation and fibrosis. People with ILD almost invariably experience dyspnea, fatigue, anxiety, depression, cough, poor health-related quality of life, and reduced exercise tolerance. Pulmonary rehabilitation (PR) is a comprehensive intervention that includes exercise training as a core and essential component and that aims to improve exercise tolerance and exertional symptoms in people with chronic lung disease. PR is a cornerstone of care for people with chronic obstructive pulmonary disease, where its role and benefits have been well defined. PR offers increasing promise as an equally effective therapy for people with ILD. This review discusses the evidence of PR for ILD, outlines the current exercise training approach for people with ILD, and discusses important areas for future research.
New Findings What is the central question of this study? Do elevated levels of the stress‐response protein NDRG2 protect against fasting and chronic disease in mouse skeletal muscle? What is the main finding and its importance? NDRG2 levels increased in the tibialis anterior muscle in response to fasting and the effects of motor neurone disease. No alleviation of the stress‐related and proteasomal pathways, mitochondrial dysfunction or muscle mass loss was observed even with the addition of exogenous NDRG2 indicating that the increase in NDRG2 is a normal adaptive response. Abstract Skeletal muscle mass loss and dysfunction can arise from stress, which leads to enhanced protein degradation and metabolic impairment. The expression of N‐myc downstream‐regulated gene 2 (NDRG2) is induced in response to different stressors and is protective against the effects of stress in some tissues and cell types. Here, we investigated the endogenous NDRG2 response to the stress of fasting and chronic disease in mice and whether exogenous NDRG2 overexpression through adeno‐associated viral (AAV) treatment ameliorated the response of skeletal muscle to these conditions. Endogenous levels of NDRG2 increased in the tibialis anterior muscle in response to 24 h fasting and with the development of the motor neurone disease, amyotrophic lateral sclerosis, in SOD1 G93A transgenic mice. Despite AAV‐induced overexpression and increased expression with fasting, NDRG2 was unable to protect against the activation of proteasomal and stress pathways in response to fasting. Furthermore, NDRG2 was unable to reduce muscle mass loss, mitochondrial dysfunction and elevated oxidative and endoplasmic reticulum stress levels in SOD1 G93A mice. Conversely, elevated NDRG2 levels did not exacerbate these stress responses. Overall, increasing NDRG2 levels might not be a useful therapeutic strategy to alleviate stress‐related disease pathologies in skeletal muscle.
Objectives: To identify exercise tests that are suitable for home-based or remote administration in people with chronic lung disease. Methods: Rapid review of studies that reported home-based or remote administration of an exercise test in people with chronic lung disease, and studies reporting their clinimetric (measurement) properties. Results: 84 studies were included. Tests used at home were the 6-minute walk test (6MWT, two studies), sit-to-stand tests (STS, five studies), Timed Up and Go (TUG, 4 studies) and step tests (two studies). Exercise tests administered remotely were the 6MWT (two studies) and step test (one study). Compared to centre-based testing the 6MWT distance was similar when performed outdoors but shorter when performed at home (two studies). The STS, TUG and step tests were feasible, reliable (intra-class correlation coefficients >0.80), valid (concurrent and known groups validity) and moderately responsive to pulmonary rehabilitation (medium effect sizes). These tests elicited less desaturation than the 6MWT, and validated methods to prescribe exercise were not reported. Discussion: The STS, step and TUG tests can be performed at home, but do not accurately document desaturation with walking or allow exercise prescription. Patients at risk of desaturation should be prioritised for centre-based exercise testing when this is available.
An example of a distributed video surveillance system is presented and the requirements on the video codec for such a system are developed. An overview of scalable video coding technologies is then provided which concludes that a wavelet based video codec offers many advantages for a distributed video surveillance system. In addition, wavelet based coding technologies offer significant error resilience properties, making them particularly robust for use on mobile networks.
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