ResearchPad - oxygen https://www.researchpad.co Default RSS Feed en-us © 2020 Newgen KnowledgeWorks <![CDATA[Automatic analysis of normative retinal oximetry images]]> https://www.researchpad.co/article/elastic_article_15756 Retinal oximetry is an important screening tool for early detection of retinal pathologies due to changes in the vasculature and also serves as a useful indicator of human-body-wide vascular abnormalities. We present an automatic technique for the measurement of oxygen saturation in retinal arterioles and venules using dual-wavelength retinal oximetry images. The technique is based on segmenting an optic-disc-centered ring-shaped region of interest and subsequent analysis of the oxygen saturation levels. We show that the two dominant peaks in the histogram of the oxygen saturation levels correspond to arteriolar and venular oxygen saturations from which the arterio-venous saturation difference (AVSD) can be calculated. For evaluation, we use a normative database of Asian Indian eyes containing 44 dual-wavelength retinal oximetry images. Validations against expert manual annotations of arterioles and venules show that the proposed technique results in an average arteriolar oxygen saturation (SatO2) of 87.48%, venular SatO2 of 57.41%, and AVSD of 30.07% in comparison with the expert ground-truth average arteriolar SatO2 of 89.41%, venular SatO2 of 56.32%, and AVSD of 33.09%, respectively. The results exhibit high consistency across the dataset indicating that the automated technique is an accurate alternative to the manual procedure.

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<![CDATA[Graphene-based 2D constructs for enhanced fibroblast support]]> https://www.researchpad.co/article/elastic_article_15755 Complex skin wounds have always been a significant health and economic problem worldwide due to their elusive and sometimes poor or non-healing conditions. If not well-treated, such wounds may lead to amputation, infections, cancer, or even death. Thus, there is a need to efficiently generate multifunctional skin grafts that address a wide range of skin conditions, including non-healing wounds, and enable the regeneration of new skin tissue. Here, we propose studying pristine graphene and two of its oxygen-functionalized derivatives—high and low-oxygen graphene films—as potential substrates for skin cell proliferation and differentiation. Using BJ cells (human foreskin-derived fibroblasts) to represent basic skin cells, we show that the changes in surface properties of pristine graphene due to oxygen functionalization do not seem to statistically impact the normal proliferation and maturation of skin cells. Our results indicate that the pristine and oxidized graphenes presented relatively low cytotoxicity to BJ fibroblasts and, in fact, support their growth and bioactivity. Therefore, these graphene films could potentially be integrated into more complex skin regenerative systems to support skin regeneration. Because graphene’s surface can be relatively easily functionalized with various chemical groups, this finding presents a major opportunity for the development of various composite materials that can act as active components in regenerative applications such as skin regeneration.

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<![CDATA[A grape seed extract maternal dietary supplementation improves egg quality and reduces ovarian steroidogenesis without affecting fertility parameters in reproductive hens]]> https://www.researchpad.co/article/elastic_article_14599 In broiler hens, the genetic selection increased susceptibility to metabolic disorders and reproductive dysfunctions. In human ovarian cells, grape seed extracts (GSE) improved steroid production. Here, we investigated the effects of a GSE dietary supplementation on egg production and quality, fertility parameters, Reactive Oxygen Species (ROS) and steroid content in yolk egg associated to plasma adipokines in broiler hens. For this, we designed two in vivo experiments, the first one included three groups of hens: A (control), B and C (supplemented with GSE at 0.5% and 1% of the total diet composition, respectively, since week 4), and the second one used two groups of hens: A (control) and D (supplemented with GSE at 1% of the total diet composition since hatching). We assessed the egg production from 23th to 40th weeks and quality at 33th week. After artificial inseminations, the fertility parameters were calculated. In egg yolk, Reactive Oxygen Species (ROS) level and steroid production were evaluated by Ros-Glo H202 and ELISA assay, respectively. Expression of steroidogenic enzymes and adipokines and their receptors was determined by RT-qPCR in ovarian cells and plasma adipokines (RARRES2, ADIPOQ and NAMPT) were evaluated by specific ELISA assays. The fertility parameters and egg production were unaffected by GSE supplementation whatever the experiment (exp.). However, the rate of double-yolk eggs decreased for all GSE supplemented groups (exp. 1 P <0.01, exp.2, P<0.02). In exp.1, C group eggs were bigger and larger (P<0.0001) and the shell elasticity was higher for both B and C (P<0.0003) as compared to control. In the egg yolk, GSE supplementation in both exp. reduced ROS content and steroidogenesis consistent with a decrease in P450 aromatase and StAR mRNA expression and basal in vitro progesterone secretion in granulosa cells (P<0.001). Interestingly, in both exp. RARRES2 plasma levels were positively correlated while ADIPOQ and NAMPT plasma levels were negatively correlated, with steroids and ROS in yolk (P<0.0001). Taken together, maternal dietary GSE supplementation did not affect egg production and fertility parameters whereas it reduced ROS content and steroidogenesis in yolk egg. Furthermore, it ameliorated egg quality by decreasing the number of double-yolk eggs and by improving the size of normal eggs and the elasticity of the shell. Taken together, our data suggest the possibility of using dietary maternal GSE to improve egg quality.

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<![CDATA[Impact of fruit orientation and pelleting material on water uptake and germination performance in artificial substrate for sugar beet]]> https://www.researchpad.co/article/elastic_article_14564 Water uptake into seeds is a fundamental prerequisite of germination and commonly influenced by commercial seed enhancement technologies. The effect of fruit orientation and contrasting pelleting materials on germination and biological performance of sugar beet was assessed. The results indicated there was orientation dependent fruit shrinkage of 37% for the operculum side supplied by moisture compared to 4% for the basal pore side. The expansion rate of 5% compared to the original size, which was also observed for non-shrinking seeds, indicated this was a temporary effect. This behaviour has importance for the application pelleting materials to seeds. Pellets composed of materials exhibiting low levels of swelling act as a water distribution layer which increased germination rates. Careful selection of pelleting material is crucial as it has direct implications on germination speed and subsequent establishment rates.

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<![CDATA[Predictive powers of the Modified Early Warning Score and the National Early Warning Score in general ward patients who activated the medical emergency team]]> https://www.researchpad.co/article/elastic_article_14562 The current early warning scores may be insufficient for medical emergency teams (METs) to use in assessing the severity and the prognosis of activated patients. We evaluated the predictive powers of the Modified Early Warning Score (MEWS) and the National Early Warning Score (NEWS) for 28-day mortality and to analyze predictors of 28-day mortality in general ward patients who activate the MET.MethodsAdult general ward inpatients who activated the MET in a tertiary referral teaching hospital between March 2009 and December 2016 were included. The demographic and clinical characteristics and physiologic parameters at the time of MET activation were collected, and MEWS and NEWS were calculated.ResultsA total of 6,729 MET activation events were analyzed. Patients who died within 28 days were younger (mean age 60 vs 62 years), were more likely to have malignancy (72% vs 53%), were more likely to be admitted to the medical department rather than the surgical department (93% vs 80%), had longer intervals from admission to MET activation (median, 7 vs 5 days), and were less likely to activate the MET during nighttime hours (5 PM to 8 AM) (61% vs 66%) compared with those who did not die within 28 days (P < 0.001 for all comparisons). The areas under the receiver operating characteristic curves of MEWS and NEWS for 28-day mortality were 0.58 (95% CI, 0.56–0.59) and 0.60 (95% CI, 0.59–0.62), which were inferior to that of the logistics regression model (0.73; 95% CI, 0.72–0.74; P < 0.001 for both comparisons).ConclusionsBoth the MEWS and NEWS had poor predictive powers for 28-day mortality in patients who activated the MET. A new scoring system is needed to stratify the severity and prognosis of patients who activated the MET. ]]> <![CDATA[Overnight polysomnography and the recording of sleep and sleep-related respiration in orchestra musicians – possible protective effects of wind instruments on respiration]]> https://www.researchpad.co/article/N88c23519-1215-408d-ac46-2899835df1cf

Our study is the first to objectively assess sleep and sleep-related respiration in orchestra musicians. We hypothesized low sleep quality due to high work demands and irregular work-sleep schedules, and a better respiration for wind instrument (WI) players than string instrument (SI) players due to habitual upper airway muscles training. We recorded overnight polysomnography with 29 professional orchestra musicians (21 men, 14 WI/ 15 SI). The musicians presented a sleep efficiency of 88% (IQR 82–92%) with WI having a significant higher sleep efficiency than SI (89%, 85–93% vs. 85%, 74–89%; p = 0.029). The group had a total sleep time around 6 hours (377min, 340-421min) with signs of increased NREM 1 (light sleep) and decreased REM (dream sleep). The musicians displayed an apnea-hypopnea-index of 2.1events/hour (0.7–5.5) and an oxygen saturation of 98% (97–100%). While SI player exhibited declining sleep-related respiration with age (breathing events: r = 0.774, p = 0.001, oxygen: r = -0.647, p = 0.009), WI player showed improved respiration with age (breathing events: r = -0.548, p = 0.043; oxygen: r = 0.610, p = 0.020). Our study is the first objective investigation of sleep pattern and respiration during sleep with overnight polysomnography in professional orchestra musicians. While sleep and respiration were unexpectedly good, our results revealed possible signs of sleep deprivation and an interesting age-related pattern on respiration depending on instrument. While sample size was small and results modest, these findings present first objective evidence towards the assumption that habitual playing of a WI–and training of the upper airway muscles–may have a protective effect on respiration.

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<![CDATA[Microlearning for patient safety: Crew resource management training in 15-minutes]]> https://www.researchpad.co/article/5c8accebd5eed0c4849902fc

Objectives

We sought to establish the feasibility of chunking crew resource management (CRM) training into micro-size interventions and to compare different training approaches in the context of micro-learning.

Design

We evaluated whether participants in micro-learning CRM activities achieved learning objectives following training. In a between-subjects design, groups were observed for behaviour during a simulation that was part of a 15-minute modular intervention and tested for recollection afterwards.

Participants

The 129 participants recruited for this study were medical students, who already had relevant experience treating patients.

Interventions

The experimental setting involved three 5-minute components: video, simulation, and debriefing. Different groups viewed videos involving different didactic concepts: one group observed a videotaped concrete example of a medical care team applying a CRM tool (example group), and one group observed a videotaped lecture on the same topic (lecture group).

Main outcome measures

All simulations were videotaped and coded in detail for the occurrence of and time spent engaging in team behaviour and medical care. Questionnaires were administered before, immediately after, and two weeks after the intervention. We compared the groups’ behaviour during the simulation (team cooperation and medical care), retention of knowledge from the training content, and results of the evaluation.

Results

Both groups exhibited most of the behaviours included in the content of the instructional videos during the simulations and recollected information 2 weeks later. The example group exhibited significantly more of the training content during the simulation and demonstrated better retention 2 weeks later. Although the example group spent more time on team coordination, there was no difference in the number of executed medical measures.

Conclusion

Delivering CRM training in chunks of relatively short and highly standardised interventions appears feasible. In this study, the form of didactical presentation caused a difference in learning success between groups: a traditional lecture was outperformed by an instructional video demonstrating a practical example.

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<![CDATA[Association between sublingual microcirculation, tissue perfusion and organ failure in major trauma: A subgroup analysis of a prospective observational study]]> https://www.researchpad.co/article/5c8823c2d5eed0c484638f67

Introduction

Previous studies described impaired microvascular perfusion and tissue oxygenation as reliable predictors of Multiple Organ Failure in major trauma. However, this relationship has been incompletely investigated. The objective of this analysis is to further evaluate the association between organ dysfunction and microcirculation after trauma.

Materials and methods

This is a retrospective subgroup analysis on 28 trauma patients enrolled for the Microcirculation DAIly MONitoring in critically ill patients study (NCT 02649088). Patients were divided in two groups according with their Sequential Organ Failure Assessment (SOFA) score at day 4. At admission and every 24 hours, the sublingual microcirculation was evaluated with Sidestream Darkfield Imaging (SDF) and peripheral tissue perfusion was assessed with Near Infrared Spectroscopy (NIRS) and Vascular Occlusion Test (VOT). Simultaneously, hemodynamic, clinical/laboratory parameters and main organ supports were collected.

Results

Median SOFA score at Day 4 was 6.5. Accordingly, patients were divided in two groups: D4-SOFA ≤6.5 and D4-SOFA >6.5. The Length of Stay in Intensive Care was significantly higher in patients with D4-SOFA>6.5 compared to D4-SOFA≤6.5 (p = 0.013). Total Vessel Density of small vessels was significantly lower in patients with high D4-SOFA score at Day 1 (p = 0.002) and Day 2 (p = 0.006) after admission; the Perfused Vessel Density was lower in patients with high D4-SOFA score at Day 1 (p = 0.007) and Day 2 (p = 0.033). At Day 1, NIRS monitoring with VOT showed significantly faster tissue oxygen saturation downslope (p = 0.018) and slower upslope (p = 0.04) in patients with high D4-SOFA.

Discussion

In our cohort of major traumas, sublingual microcirculation and peripheral microvascular reactivity were significantly more impaired early after trauma in those patients who developed more severe organ dysfunctions. Our data would support the hypothesis that restoration of macrocirculation can be dissociated from restoration of peripheral and tissue perfusion, and that microvascular alterations can be associated with organ failure.

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<![CDATA[Intra-hospital transport of critically ill patients with rapid response team and risk factors for cardiopulmonary arrest: A retrospective cohort study]]> https://www.researchpad.co/article/5c8823c5d5eed0c484638fbe

Introduction

This study aimed to determine the occurrence rate and risk factors of cardiopulmonary arrest (CPA) during intra-hospital transport (IHT) among critically ill patients, accompanied by a rapid response team (RRT).

Methods

We performed a retrospective cohort study in a 1300-bed tertiary-care teaching hospital. Data of all admitted patients transported within the hospital and accompanied by the RRT from October 2012 to May 2016 were included. We compared patients with CPA (+) and patients without CPA (-) to identify risk factors for CPA during transport.

Results

Among 535 patients, CPA occurred in eight (1.5%) patients during IHT. There were no significant differences in age, sex, and comorbidities between groups. More patients in the CPA (+) group than in the CPA (-) group received manual ventilation during IHT (75% vs. 23.0%, p = 0.001). An increased risk of CPA (p<0.001) corresponded with a higher number of vasopressors used during IHT. In univariate logistic regression analysis, history of myocardial infarction (OR 10.7, 95% CI 2.4–50.5, p = 0.005), manual ventilation (OR 10.1, 95% CI 2.0–50.5, p = 0.005), and use of three or more vasopressors (OR 11.1, 95% CI 2.5–48.9, p = 0.001) were significantly associated with risk of CPA during RRT-led IHT.

Conclusions

Despite accompaniment by a specialized team such as the RRT, CPA can occur during IHT. History of myocardial infarction, manual ventilation with bag-valve mask, and the use of three or more vasopressors were independent risk factors of CPA during IHT of critically ill patients accompanied by the RRT.

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<![CDATA[Exploring clinical, echocardiographic and molecular biomarkers to predict bronchopulmonary dysplasia]]> https://www.researchpad.co/article/5c89778ad5eed0c4847d2f5c

Introduction

Bronchopulmonary dysplasia (BPD) is the most common chronic lung disease in childhood, related to prematurity, and the most common cause of pulmonary hypertension (PH) secondary to pulmonary disease in children. Moderate and severe BPD have a worse outcome and relate more frequently with PH. The prediction of moderate or severe BPD development in extremely premature newborns is vital to implement preventive strategies. Starting with the hypothesis that molecular biomarkers were better than clinical and echocardiographic factors, this study aims to explore the ability of clinical, echocardiographic and analytical variables to predict moderate or severe BPD in a cohort of extremely preterm infants.

Patients and methods

We designed a prospective longitudinal study, in which we followed a cohort of preterm newborns (gestational age <28 weeks and weight ≤ 1250 grams). In these newborns we recorded weekly clinical and echocardiographic variables as well as blood and tracheal aspirate samples, to analyze molecular biomarkers (IL-6, IL-1, IP10, uric acid, HGF, endothelin-1, VEGF, CCL5). Variables and samples were collected since birth up to week 36 (postmenstrual age), time-point at which the diagnosis of BPD is established.

Results

We included 50 patients with a median gestational age of 26 weeks (IQR 25–27) and weight of 871 g (SD 161,0) (range 590-1200g). Three patients were excluded due to an early death. Thirty-five patients (74.5%) developed BPD (mild n = 14, moderate n = 15, severe n = 6). We performed a logistic regression in order to identify risk factors for moderate or severe BPD. We compared two predictive models, one with two variables (mechanical ventilation and inter-ventricular septum flattening), and another-one with an additional molecular biomarker (ET-1).

Conclusions

The combination of clinical and echocardiographic variables is a valuable tool for determining the risk of BPD. We find the two variable model (mechanical ventilation and echocardiographic signs of PH) more practical for clinical and research purposes. Future research on BPD prediction should be oriented to explore the potential role of ET-1.

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<![CDATA[Synthesis and characterizations of o-nitrochitosan based biopolymer electrolyte for electrochemical devices]]> https://www.researchpad.co/article/5c706761d5eed0c4847c6f87

For the past decade, much attention was focused on polysaccharide natural resources for various purposes. Throughout the works, several efforts were reported to prepare new function of chitosan by chemical modifications for renewable energy, such as fuel cell application. This paper focuses on synthesis of the chitosan derivative, namely, O-nitrochitosan which was synthesized at various compositions of sodium hydroxide and reacted with nitric acid fume. Its potential as biopolymer electrolytes was studied. The substitution of nitro group was analyzed by using Attenuated Total Reflectance Fourier Transform Infra-Red (ATR-FTIR) analysis, Nuclear Magnetic Resonance (NMR) and Elemental Analysis (CHNS). The structure was characterized by X-ray Diffraction (XRD) and its thermal properties were examined by using differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). Whereas, the ionic conductivity of the samples was analyzed by electrochemical impedance spectroscopy (EIS). From the IR spectrum results, the nitro group peaks of O-nitrochitosan, positioned at 1646 and 1355 cm-1, were clearly seen for all pH media. At pH 6, O-nitrochitosan exhibited the highest degree of substitution at 0.74 when analyzed by CHNS analysis and NMR further proved that C-6 of glucosamine ring was shifted to the higher field. However, the thermal stability and glass transition temperatures were decreased with acidic condition. The highest ionic conductivity of O-nitrochitosan was obtained at ~10−6 cm-1. Overall, the electrochemical property of new O-nitrochitosan showed a good improvement as compared to chitosan and other chitosan derivatives. Hence, O-nitrochitosan is a promising biopolymer electrolyte and has the potential to be applied in electrochemical devices.

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<![CDATA[Cardiopulmonary responses to maximal aerobic exercise in patients with cystic fibrosis]]> https://www.researchpad.co/article/5c6dca0ed5eed0c48452a718

Cystic fibrosis (CF) is a debilitating chronic condition, which requires complex and expensive disease management. Exercise has now been recognised as a critical factor in improving health and quality of life in patients with CF. Hence, cardiopulmonary exercise testing (CPET) is used to determine aerobic fitness of young patients as part of the clinical management of CF. However, at present there is a lack of conclusive evidence for one limiting system of aerobic fitness for CF patients at individual patient level. Here, we perform detailed data analysis that allows us to identify important systems-level factors that affect aerobic fitness. We use patients’ data and principal component analysis to confirm the dependence of CPET performance on variables associated with ventilation and metabolic rates of oxygen consumption. We find that the time at which participants cross the gas exchange threshold (GET) is well correlated with their overall performance. Furthermore, we propose a predictive modelling framework that captures the relationship between ventilatory dynamics, lung capacity and function and performance in CPET within a group of children and adolescents with CF. Specifically, we show that using Gaussian processes (GP) we can predict GET at the individual patient level with reasonable accuracy given the small sample size of the available group of patients. We conclude by presenting an example and future perspectives for improving and extending the proposed framework. The modelling and analysis have the potential to pave the way to designing personalised exercise programmes that are tailored to specific individual needs relative to patient’s treatment therapies.

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<![CDATA[Elevated levels of autoantibodies against EXD2 and PHAX in the sera of patients with chronic thromboembolic pulmonary hypertension]]> https://www.researchpad.co/article/5c6dca33d5eed0c48452a8b5

While circulating autoantibodies have been detected in patients with several cardiovascular diseases, such studies have not been performed for chronic thromboembolic pulmonary hypertension (CTEPH) and pulmonary arterial hypertension (PAH). Here we investigated the production of certain auto-antibodies in CTEPH patients. Initial screening was performed in 5 CTEPH patients and 5 healthy donors (HDs) using a ProtoArray Human Protein Microarray v5.1 containing 9,375 human proteins, and we selected 34 antigens recognized by IgG antibodies more strongly in the sera of CTEPH patients than in the sera of HDs. In subsequent second/third analyses, we validated the auto-antibody level using amplified luminescent proximity homogeneous assay-linked immunosorbent assay (AlphaLISA) in 96 CTEPH patients and 96 HDs as follows: At the second screening, we used 63 crude peptides derived from those selected 34 antigens and found that the serum levels of autoantibodies for 4 peptides seemed higher in CTEPH patients than in HDs. In third analysis, we used the purified peptides of those selected in second screening and found that serum antibodies against peptides derived from exonuclease 3'-5' domain-containing 2 (EXD2) and phosphorylated adaptor for RNA export (PHAX) were significantly higher in CTEPH patients than in HDs. The serum antibody levels to these antigens were also elevated in PAH patients. The titers against EXD2 peptide decreased after surgical treatment in CTEPH patients. These autoantibodies may be useful as biomarkers of CTEPH and PAH, and further investigations may provide novel insight into the etiology.

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<![CDATA[Impact of different stages of intrauterine inflammation on outcome of preterm neonates: Gestational age-dependent and -independent effect]]> https://www.researchpad.co/article/5c6730e6d5eed0c484f382c7

Objective

To investigate the impact of different stages of intrauterine inflammation (IUI) on neonatal outcomes, before and after adjusting for gestational age (GA) and other perinatal confounders.

Methods

This was an observational, prospective, single-center cohort study including all eligible neonates with GA < 35 weeks and/or birth weight ≤ 1500 g born at a 3rd level Neonatal Intensive Care Unit between 2011 and 2014. Pathological patterns of placenta, membranes and cord were classified according to Redline’s criteria. Multivariable linear and logistic regression models were applied, either including or not GA among the covariates.

Results

Of the 807 enrolled neonates, 134 (16.6%) had signs of IUI: among these, 54.5% showed just histological chorioamnionitis (HCA), 25.4% had HCA + funisitis (FUN) stage 1, and 20.1% had HCA + FUN stage 2–3. At univariate analysis, HCA increased the risk for retinopathy of prematurity (ROP) and bronchopulmonary dysplasia, while FUN (any stage) had a deleterious impact on all outcomes investigated. After adjustment for covariates not including GA, HCA was a risk factor only for ROP (OR = 2.8, CI: 1–7.8), while FUN (any stage) was still associated with increased ORs for all outcomes (p <0.01). Upon inclusion of GA in the regression model, the results differed remarkably. HCA was associated with lower risk for mechanical ventilation (OR = 0.3, CI: 0.1–0.7) and need for surfactant (OR = 0.5, CI: 0.2–0.9), while FUN (any stage) worsened clinical conditions at birth (p <0.05), increased the risk for early-onset sepsis (p <0.01), and increased the length of mechanical ventilation (FUN stage 2–3 only, RC = 6.5 days, CI: 2–11). No other outcome was affected.

Conclusions

IUI, especially FUN, negatively impact most neonatal morbidities, but its effect is partially reverted adjusting for GA. Considered that GA is an intermediate variable interposed between prenatal causes of prematurity and outcomes, the appropriateness of adjusting for GA may be questionable.

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<![CDATA[Assessment of a storage system to deliver uninterrupted therapeutic oxygen during power outages in resource-limited settings]]> https://www.researchpad.co/article/5c648cd4d5eed0c484c818b0

Access to therapeutic oxygen remains a challenge in the effort to reduce pneumonia mortality among children in low- and middle-income countries. The use of oxygen concentrators is common, but their effectiveness in delivering uninterrupted oxygen is gated by reliability of the power grid. Often cylinders are employed to provide continuous coverage, but these can present other logistical challenges. In this study, we examined the use of a novel, low-pressure oxygen storage system to capture excess oxygen from a concentrator to be delivered to patients during an outage. A prototype was built and tested in a non-clinical trial in Jinja, Uganda. The trial was carried out at Jinja Regional Referral Hospital over a 75-day period. The flow rate of the unit was adjusted once per week between 0.5 and 5 liters per minute. Over the trial period, 1284 power failure episodes with a mean duration of 3.1 minutes (range 0.08 to 1720 minutes) were recorded. The low-pressure system was able to deliver oxygen over 56% of the 4,295 power outage minutes and cover over 99% of power outage events over the course of the study. These results demonstrate the technical feasibility of a method to extend oxygen availability and provide a basis for clinical trials.

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<![CDATA[Melatonin decreases M1 polarization via attenuating mitochondrial oxidative damage depending on UCP2 pathway in prorenin-treated microglia]]> https://www.researchpad.co/article/5c6b266ad5eed0c484289a2f

Accumulating evidence suggests that neuroinflammation and oxidative stress in cardiovascular center contribute to the pathological processes underlying hypertension. Microglia activation triggers the inflammation and oxidative stress. Melatonin is a documented potent anti-inflammatory regent and antioxidant, the underlying roles of melatonin in regulating microglia activation via mitochondria remain unclear. In present study, we investigated the protective role of melatonin in decreasing M1 phenotype switching via attenuating mitochondrial oxidative damage in dependence on uncoupling protein 2 (UCP2) pathway in microglia. Prorenin (20 nmol/L; 24 hr) was used to induce inflammation in cultured microglia. Mitochondrial morphology was detected by transmission electron microscope. The reactive oxygen species (ROS) production by using DCFH-DA fluorescence imaging and mitochondrial membrane potential (MMP, ΔΨm) was evaluated by JC-1 staining. The indicator of the redox status as the ratio of the amount of total NADP+ to total NADPH, and the expression of 6 subunits of NADPH oxidase is measured. The pro-inflammatory cytokines releasing was measured by qPCR. UCP2 and activated AMPKα (p-AMPKα) expression were examined by immunoblot. Melatonin (100 μM) markedly alleviated the M1 microglia phenotype shifting and abnormal mitochondria morphology. Melatonin attenuated prorenin-induced ΔΨm increasing and ROS overproduction. Melatonin decreased the redox ratio (NADP+/NADPH) and the p47phox and gp91phox subunits of NADPH oxidase expression in prorenin-treated microglia. These effects were reversed in the presence of UCP2 siRNA. Our results suggested that the protective effect of melatonin against prorenin-induced M1 phenotype switching via attenuating mitochondrial oxidative damage depending on UCP2 upregulation in prorenin-treated microglia.

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<![CDATA[Leave or stay? Video-logger revealed foraging efficiency of humpback whales under temporal change in prey density]]> https://www.researchpad.co/article/5c63392dd5eed0c484ae6172

Central place foraging theory (CPF) has been used to predict the optimal patch residence time for air-breathing marine predators in response to patch quality. Humpback whales (Megaptera novaeangliae) forage on densely aggregated prey, which may induce drastic change in prey density in a single feeding event. Thus, the decision whether to leave or stay after each feeding event in a single dive in response to this drastic change, should have a significant effect on prey exploitation efficiency. However, whether humpback whales show adaptive behavior in response to the diminishing prey density in a single dive has been technically difficult to test. Here, we studied the foraging behavior of humpback whales in response to change in prey density in a single dive and calculated the efficiency of each foraging dive using a model based on CPF approach. Using animal-borne accelerometers and video loggers attached to whales, foraging behavior and change in relative prey density in front of the whales were successfully quantified. Results showed diminishing rate of energy intake in consecutive feeding events, and humpback whales efficiently fed by bringing the rate of energy intake close to maximum in a single dive cycle. This video-based method also enabled us to detect the presence of other animals around the tagged whales, showing an interesting trend in behavioral changes where feeding duration was shorter when other animals were present. Our results have introduced a new potential to quantitatively investigate the effect of other animals on free-ranging top predators in the context of optimal foraging theory.

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<![CDATA[Impact of moderate to severe obstructive sleep apnea on the cognition in idiopathic pulmonary fibrosis]]> https://www.researchpad.co/article/5c5df31bd5eed0c484580d2d

Introduction

Idiopathic pulmonary fibrosis (IPF) is a relentlessly progressive lung disease with a fatal prognosis to whose rapid evolution multiple comorbidities may contribute, one of the most common being obstructive sleep apnea (OSA). There are several potential factors and conditions for the emergence of a cognitive deficit in relation to IPF or associated morbidities.

Objectives

The goals of this study were to assess cognition in patients with IPF in stable phase and to identify clinical cognition modifiers.

Methods

In a cross-sectional study, 23 patients with IPF were evaluated using Montreal Cognitive Assessment (MoCA), an instrument for detecting mild cognitive impairments and were screened for OSA through overnight cardiorespiratory polygraphy and for anxiety and depression with three specific scale (Generalized Anxiety Disorder 7-item scale: GAD-7; the Patient Health Questionnaire: PHQ-9; Hospital Anxiety and Depression Scale: HADS).

Results

MoCA score was lower in patients with IPF when compared to controls subjects (24 [21,26] vs. 27 [26,28], p = 0.003) but not as significantly as in COPD patients (21 [18.8,23.3], p<0.0001). OSA was diagnosed in 19 (82.6%) IPF patients, 12 patients showed the presence of moderate-severe forms (63.15%). IPF patients with cognitive impairment (MoCA<23) exhibit a higher severity of OSA (apneea hypopnea index–AHI: 33.0±19.1 vs. 12.44±8.2, p = 0.018), and a higher Epworth score (7.1±3.3 vs. 4.3±1.8, p = 0.013). Anxiety and depression scores were not correlated with MoCA results.

Conclusions

Impaired cognition in patients with IPF is mild and affect the areas of visuospatial abilities, language and working memory. OSA could be a possible predictor of IPF cognition deficit. Given the high prevalence of multiple types of sleep disorders in IPF patients, these should be investigated at least by cardiorespiratory polygraphy.

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<![CDATA[Validation of an equation for energy expenditure that does not require the respiratory quotient]]> https://www.researchpad.co/article/5c5df330d5eed0c484580e72

Background

Energy expenditure (EE) calculated from respirometric indirect calorimetry is most accurate when based on oxygen consumption (VO2), carbon dioxide production (VCO2) and estimated protein metabolism (PM). EE has a substantial dependence of ~7% on the respiratory quotient (RQ, VCO2/VO2) and a lesser dependence on PM, yet many studies have instead estimated EE from VO2 only while PM has often been ignored, thus reducing accuracy. In 1949 Weir proposed a method to accurately calculate EE without using RQ, which also adjusts for estimated PM based on dietary composition. This RQ- method utilizes the calorimeter airflow rate (FR), the change in fractional O2 concentration (ΔFO2) and the dietary protein fraction. The RQ- method has not previously been empirically validated against the standard RQ+ method using both VO2 and RQ. Our aim was to do that.

Methods

VO2 and VCO2 were measured repeatedly in 8 mice fed a high protein diet (HPD) during exposure to different temperatures (n = 168 measurements of 24h gas exchange). The HPD-adjusted RQ+ equation was: EE [kcal/time] = VO2 [L/time]×(3.853+1.081RQ) while the corresponding RQ- equation was: EE = 4.934×FR×ΔFO2. Agreement was analyzed using the ratios of the RQ- to RQ+ methods along with regression and Bland-Altman agreement analyses. We also evaluated the standard equation using the dietary food quotient (FQ) of 0.91 as a proxy for RQ (FQ+ method).

Results

Ratio analysis revealed that the mean error of the RQ- method was only 0.11 ± 0.042% while the maximum error was only 0.21%. Error using the FQ+ method was 4 -and 10-fold greater, respectively. Bland-Altman analysis demonstrated that the RQ- method very slightly overestimates EE as RQ decreases. Theoretically, this error can be eliminated completely by imposing an incurrent fractional oxygen concentration at a value only slightly greater than the atmospheric level.

Conclusions

The Weir ‘RQ-free’ method for calculating EE is a highly valid alternative to the ‘gold standard’ method that requires RQ. The RQ- approach permits reduced cost and complexity in studies focused on EE and provides a way to rescue EE measurement in studies compromised by faulty CO2 measurements. Practitioners of respirometry should consider adjusting EE calculations for estimated protein metabolism based on dietary composition.

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<![CDATA[Development and validation of a questionnaire to assess the doctors and nurses knowledge of acute oxygen therapy]]> https://www.researchpad.co/article/5c61e924d5eed0c48496f865

Background

Prescription and administration of oxygen in emergencies by healthcare providers are reported to be inappropriate in most settings. There is a huge gap in the knowledge of health care providers on various aspects of oxygen therapy, and this may be a barrier to optimal oxygen administration. Hence, it is essential to ascertain providers’ knowledge of acute oxygen therapy so that appropriate educational interventions are instituted for better delivery. There is no available validated instrument to assess knowledge of acute oxygen therapy. The study aimed to develop, validate and evaluate the test-retest reliability of a questionnaire to determine the doctors and nurses understanding of acute oxygen therapy.

Methods

This study involved the development of the questionnaire contents by a literature review, assessment of face validity (n = 5), content validity, using a panel of experts (n = 10), item analysis and test-retest reliability among a sample (n = 121) of doctors and nurses.

Results

Face validity indicated that the questionnaire was quick to complete (10–15 min), most items were easy to follow and comprehensible. The global content validity index (S-CVI) was 0.85. The test-retest reliability statistics showed a kappa coefficient of 0.546–0.897 (all P<0.001) and percentage agreement of 80–98.3% indicating high temporal stability in the target population. In total, 90% of the items fulfilled the reliability acceptance criteria. Item discrimination analysis showed that most questions were at an acceptable level. The final questionnaire included 37 item questions and eight sections.

Conclusion

The designed questionnaire is a reliable and valid tool for assessing knowledge of acute oxygen therapy among doctors and nurses.

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