Aging increases metabolic capacity and reduces work efficiency during handgrip exercise in males

Maximal oxygen uptake and exercise performance typically decline with age. However, there are indications of preserved vascular function and blood flow regulation during arm exercise. Yet, it is unknown if this potential physiological preservation with age is mirrored in peripheral metabolic capacity and V̇O2/watt ratio. Thus, to investigate the effects of aging in the arms, we measured metabolic and vascular responses to 6-minute bouts of dynamic handgrip exercise at 40% and 80% of maximal work rate (WRmax) in eleven young (26±2yr) and twelve old (80±6yr) males, applying Doppler-ultrasound combined with blood samples from a deep forearm vein. At baseline, old had a larger arterial diameter compared to young (p<0.001). During exercise, the two groups reached the same WRmax. V̇O2, blood flow, and oxygen supply were higher (40%WRmax; 80%WRmax, all p<0.01), and arterio-venous oxygen-difference lower (80%WRmax, p<0.02), in old compared to young. Old also had a higher oxygen-excess at 80%WRmax (p<0.01) than young, while no difference in muscle diffusion or oxygen-extraction was detected. Only young exhibited an increase in intensity-induced arterial dilation (p<0.05), and they had a lower mean arterial pressure than old at 80%WRmax (p<0.001). V̇O2/watt (40%WRmax; 80%WRmax) was reduced in old compared to young (both p<0.05). In conclusion, in old and young males with a similar handgrip WRmax, old had a higher V̇O2 during 80%WRmax intensity, achieved by an increased blood flow. This may be a result of the available cardiac output reserve, compensating for reduced work efficiency and attenuated vascular response observed in old

Maximal strength training-induced improvements in forearm work efficiency are associated with reduced blood flow

Maximal strength training (MST) improves work efficiency. However, since blood flow is greatly dictated by muscle contractions in arms during exercise, and vascular conductance is lower, it has been indicated that arms rely more upon adapting oxygen extraction than legs in response to the enhanced work efficiency. Thus, to investigate if metabolic and vascular responses are arm-specific, we utilized Doppler-ultrasound and a catheter placed in the subclavian vein to measure blood flow and a-vO2diff during steady state work in seven young males (24{plus minus}3(SD) years) following six-weeks of handgrip MST. As expected, MST improved maximal strength (49{plus minus}9 to 62{plus minus}10kg) and rate of force development (923{plus minus}224 to 1086{plus minus}238N·s-1), resulting in a reduced submaximal V̇O2 (30{plus minus}9 to 24{plus minus}10ml·min-1) and concomitantly increased work efficiency (9.3{plus minus}2.5 to 12.4{plus minus}3.9%) (all p<0.05). In turn, the work efficiency improvement was associated with a reduced blood flow (486{plus minus}102 to 395{plus minus}114ml·min-1), mediated by a lower blood velocity (43{plus minus}8 to 32{plus minus}6cm·s-1) (all p<0.05). Conduit artery diameter and a-vO2diff remained unaltered. The maximal work test revealed increased time to exhaustion (949{plus minus}239 to 1102{plus minus}292seconds) and maximal work rate (both p<0.05), but no change in peak oxygen uptake. In conclusion, despite prior indications of metabolic and vascular limb-specific differences, these results reveal that improved work efficiency following small muscle mass strength training in the upper extremities is accompanied by a blood flow reduction, and coheres with what has been documented for lower extremities.publishedVersio

Simulation of Oil Production from Homogenous North Sea Reservoirs with Inflow Control using OLGA/Rocx

Advances in drilling technology have made long, horizontal wells the preferred method to extract oil from reservoirs in the Norwegian Sector. Early water or gas breakthrough is a passive inflow control devices (ICD) are installed to even out the drawdown. However, a new technology called Autonomous Inflow Control Valve (AICV©) has the ability to autonomously close each individual inflow zone in the event of gas or water breakthrough. The objective of this paper was to study and compare these inflow control technologies. This was accomplished by conducting simulations in OLGA/Rocx. For this study, a high-permeability homogenous sandstone heavy oil reservoir was modelled based on data from the Grane oil field in the North Sea. Comparison of the oil production from the simulations with ICD and AICV completion was performed. The results, based on a time interval of 600 days, show that the oil production is 8% less and the water production is 43% less if AICV is used compared to ICD. This indicates that AICV has the potential to reduce the water production significantly in a homogeneous reservoir

Data on association between QRS duration on prehospital ECG and mortality in patients with confirmed STEMI

Data presented in this article relates to the research article entitled âAssociation between QRS duration on prehospital ECG and mortality in patients with suspected STEMIâ (Hansen et al., in press) [1].Data on the prognostic effect of automatically recoded QRS duration on prehospital ECG and presence of classic left and right bundle branch block in 1777 consecutive patients with confirmed ST segment elevation AMI is presented. Multivariable analysis, suggested that QRS duration >111 ms, left bundle branch block and right bundle branch block were independent predictors of 30 days all-cause mortality. For interpretation and discussion of these data, refer to the research article referenced above

Respiratory dysfunction three months after severe COVID-19 is associated with gut microbiota alterations

Background: Although coronavirus disease 2019 (COVID-19) is primarily a respiratory infection, mounting evidence suggests that the gastrointestinal (GI) tract is involved in the disease, with gut barrier dysfunction and gut microbiota alterations being related to disease severity. Whether these alterations persist and are related to long-term respiratory dysfunction remains unknown. Methods: Plasma was collected during hospital admission and after three months from the NOR-Solidarity trial (n = 181) and analysed for markers of gut barrier dysfunction and inflammation. At the three-month follow-up, pulmonary function was assessed by measuring the diffusing capacity of the lungs for carbon monoxide (DLCO ). Rectal swabs for gut microbiota analyses were collected (n = 97) and analysed by sequencing the 16S rRNA gene. Results: Gut microbiota diversity was reduced in COVID-19 patients with respiratory dysfunction, defined as DLCO below the lower limit of normal three months after hospitalisation. These patients also had an altered global gut microbiota composition, with reduced relative abundance of 20 bacterial taxa and increased abundance of five taxa, including Veillonella, potentially linked to fibrosis. During hospitalisation, increased plasma levels of lipopolysaccharide-binding protein (LBP) were strongly associated with respiratory failure, defined as pO2 /fiO2 -(P/F ratio)Respiratory dysfunction three months after severe COVID-19 is associated with gut microbiota alterationsacceptedVersio

Differential contributions of specimen types, culturing, and 16S rRNA sequencing in diagnosis of prosthetic joint infections

ABSTRACT Prosthetic joint failure is mainly caused by infection, aseptic failure (AF), and mechanical problems. Infection detection has been improved with modified culture methods and molecular diagnostics. However, comparisons between modified and conventional microbiology methods are difficult due to variations in specimen sampling. In this prospective, multidisciplinary study of hip or knee prosthetic failures, we assessed the contributions of different specimen types, extended culture incubations, and 16S rRNA sequencing for diagnosing prosthetic joint infections (PJI). Project specimens included joint fluid (JF), bone biopsy specimens (BB), soft-tissue biopsy specimens (STB), and swabs (SW) from the prosthesis, collected in situ , and sonication fluid collected from prosthetic components (PC). Specimens were cultured for 6 (conventional) or 14 days, and 16S rRNA sequencing was performed at study completion. Of the 156 patients enrolled, 111 underwent 114 surgical revisions (cases) due to indications of either PJI ( n = 43) or AF ( n = 71). Conventional tissue biopsy cultures confirmed PJI in 28/43 (65%) cases and refuted AF in 3/71 (4%) cases; one case was not evaluable. Based on these results, minor diagnostic adjustments were made. Fourteen-day cultures of JF, STB, and PC specimens confirmed PJI in 39/42 (93%) cases, and 16S rRNA sequencing confirmed PJI in 33/42 (83%) cases. One PJI case was confirmed with 16S rRNA sequencing alone and five with cultures of project specimens alone. These findings indicated that JF, STB, and PC specimen cultures qualified as an optimal diagnostic set. The contribution of sequencing to diagnosis of PJI may depend on patient selection; this hypothesis requires further investigation. </jats:p