► Nanomaterials interfere with most in vitro fluorimetric screening tests. ► We explore the usefulness of DCFH-DA test to asses NP-induced oxidative stress. ► NP uptake correlated with quenching of ...dye fluorescence emission. ► Minor changes in DCFH-DA protocol allowed quantification of free radical formation. ► Protocol modifications did not result in free radical formation for all tested NPs.
No consensus exists on how to address possible toxicity of nanomaterials as they interfere with most in vitro screening tests based on colorimetric and fluorimetric probes such as the dichloro-dihydro-fluorescein diacetate (DCFH-DA) assay for detection of oxidative species.
In the present research, nanomaterial interaction with DCFH-DA was studied in relation to its nature and/or assay conditions (cell-based and time exposure) by incubating Rhodamine (Rhd)-labeled 25nm and 50nm silica (SiO2), naked and oleic acid coated magnetite, (Fe3O4) and maghemite (Fe2O3) iron oxide, titanium dioxide (TiO2) and poly(ethylene oxide)-poly(lactide/glycolide) acid (PLGA-PEO) nanoparticles (NPs) with metabolically active rat hepatocytes for 4 and 24-h periods. Data indicated that nanoparticle uptake correlated with quenching of dye fluorescence emission. In spite of their masking effect, the oxidative potential of NPs could be detected at a limited threshold concentration when exposed for periods of time longer than those frequently used for this test. However, changes in the experimental conditions did not systematically result in free radical formation for all nanomaterials tested.
Overall data indicate that despite the quenching effect of nanoparticles on DCFH-DA assay, it can be considered as a useful tool for quantitative measurement of NPs-induced oxidative stress by minor modifications of standardized protocols.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Endotracheal intubation and mechanical ventilation are major components of routine intensive care for very low birth weight newborns and sick full-term newborns. These procedures are associated with ...physiologic, biochemical, and clinical responses indicating pain and stress in the newborn. Most neonates receive some form of analgesia and sedation during mechanical ventilation, although there are marked variations in clinical practice. Clinical guidelines for pharmacologic analgesia and sedation in newborns based on robust scientific data are lacking, as are measures of clinical efficacy.
This article represents a preliminary attempt to develop a scientific rationale for analgesia sedation in mechanically ventilated newborns based on a systematic analysis of published clinical trials.
The current literature was reviewed with regard to the use of opioids (fentanyl, morphine, diamorphine), sedative-hypnotics (midazolam), nonsteroidal anti-inflammatory drugs (ibuprofen, indomethacin), and acetaminophen in ventilated neonates. Original meta-analyses were conducted that collated the data from randomized clinical comparisons of morphine or fentanyl with placebo, or morphine with fentanyl.
The results of randomized trials comparing fentanyl, morphine, or midazolam with placebo, and fentanyl with morphine were inconclusive because of small sample sizes. Meta-analyses of the randomized controlled trials indicated that morphine and fentanyl can reduce behavioral and physiologic measures of pain and stress in mechanically ventilated preterm neonates but may prolong the duration of ventilation or produce other adverse effects. Randomized trials of midazolam compared with placebo reported significant adverse effects (P < 0.05) and no apparent clinical benefit; the findings of a meta-analysis suggest that there are insufficient data to justify use of IV midazolam for sedation in ventilated neonates.
Despite ongoing research in this area, huge gaps in our knowledge remain. Well-designed and adequately powered clinical trials are needed to establish the safety, efficacy, and short- and long-term outcomes of analgesia and sedation in the mechanically ventilated newborn.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The electrical response of carbon nanotube yarns (CNTYs) under alternating (AC) and direct current (DC) is investigated. Electrical measurements are conducted simultaneously with application of ...strain and under in situ Raman spectroscopy. In situ Raman spectroscopy is used to better understand the loading mechanisms and the electromechanical response of the CNTY upon axial stretching. The AC electrical response of the CNTYs is dominated by its resistive component, and a capacitive contribution arises at high frequencies (f > 105 Hz). This response obeys the hierarchical structure of the CNTY, where porosity between bundles form microcapacitors. Under AC, the impedance modulus showed a positive electrical sensitivity to strain with a maximum value of 0.33 at 100 kHz. This is slightly higher than the DC one (0.25). The AC phase angle showed very low sensitivity to strain. The small shift of the Raman bands with strain suggests that structural deformations at the bundle level are the dominant deformation mechanism. While the Raman shift is weak to identify unwinding and detaching of bundles, both the AC and DC electrical responses pinpoint such damage mechanisms by a change in trend. The promising application of the impedance response to monitor the curing kinetics of thermosetting polymers is proved.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The design and analysis of a device to measure the burst strength (strength under a state of pure radial internal pressure) and compliance of vascular grafts and flexible pressurized tubes is ...presented. The device comprises three main sections, viz., a clean air-dry pressure controller, a test specimen holder, and automated software for control and data collection. Air pressure is controlled by means of a valve and a dedicated mechanism allowing reaching up to 120 psi in increments of 1 psi, and recording pressure changes with 0.04 psi resolution. The circumferential strain is determined by measuring the radial displacement of the vascular graft using an optical arrangement capable of determining a maximum radial displacement of 10 mm with 0.02 mm resolution. The instrument provides a low uncertainty in compliance (±0.32%/100 mm Hg
) and burst strength measurements. Due to its simplicity, the device can easily be reproduced in other laboratories contributing to a dedicated instrument with high resolution at low cost. The reliability of the apparatus is further confirmed by conducting finite element analysis, elasticity solutions for pressurized cylinders, and testing of small diameter vascular grafts made of a commercial aliphatic polyurethane tested under radial internal pressure.
Electrical and piezoresistive properties of hybrid nanocomposite films and tubes made of a segmented aliphatic polyurethane modified with multilayer graphene sheets (MLGSs), multiwall carbon ...nanotubes (MWCNTs), and hybrid mixtures of both, were investigated. Hybrid nanocomposites were fabricated at a total weight concentration ( ΦT) of 5 wt.%, with relative weight concentration of MLGSs with respect to MWCNTs ( ΦR) of 25%, 50% and 75%. The electrical conductivity of these films is dominated by the MWCNT network, observing electrical MLGS-MWCNT collaborative effects only for ΦR = 25%. Dielectric impedance spectroscopy indicates that the nanocomposites display capacitive effects at frequencies higher than tens of Hz, which is explained by interfacial polarization. The burst pressure and circumferential stiffness of internally pressurized tubes fabricated from these films is slightly higher for tubes containing only MWCNTs. The strain fields in the pressurized tubes, determined by digital image correlation, showed localized strain gradients, and the piezoresistive response of the electro-conductive tubes was nonlinear. The highest pressure sensitivity factor (4.59 kPa−1) was obtained for hybrid nanocomposite tubes with ΦR = 25%.
Recent advances in neurobiology and clinical medicine have established that the fetus and newborn may experience acute, established, and chronic pain. They respond to such noxious stimuli by a series ...of complex biochemical, physiologic, and behavioral alterations. Studies have concluded that controlling pain experience is beneficial with respect to short-term and perhaps long-term outcomes. Yet, pain-control measures are adopted infrequently because of unresolved scientific issues and lack of appreciation for the need for control of pain and its long-term sequelae during the critical phases of neurologic maturation in the preterm and term newborn. The neonatal pain-control group, as part of the Newborn Drug Development Initiative (NDDI) Workshop I, addressed these concerns. The specific issues addressed were (1) management of pain associated with invasive procedures, (2) provision of sedation and analgesia during mechanical ventilation, and (3) mitigation of pain and stress responses during and after surgery in the newborn infant. The cross-cutting themes addressed within each category included (1) clinical-trial designs, (2) drug prioritization, (3) ethical constraints, (4) gaps in our knowledge, and (5) future research needs. This article provides a summary of the discussions and deliberations. Full-length articles on procedural pain, sedation and analgesia for ventilated infants, perioperative pain, and study designs for neonatal pain research were published in Clinical Therapeutics (June 2005).
The circumferential compliance and burst strength of vascular grafts are predicted through the conically modified von Mises and elasticity theories, providing an analytical closed form solution for ...both parameters. Besides the graft's radii, the model for circumferential compliance depends solely on the elastic modulus and Poisson's ratio of the polymer material, and its accuracy was verified by finite element analysis and measurements. The analytical expression of the burst strength requires accurate determination of the material's tensile and compressive yield stress, which were carefully obtained by using digital image correlation measurements in uniaxial tensile and compressive tests of the constitutive material. The average measured circumferential compliance and burst strength of an 8mm graft made of a commonly used biomaterial, Tecoflex
SG-80A, are 1.05%/100mmHg
and 34.1psi (1763mmHg) and the proposed analytical predictions fall within the experimental scattering. Thus, it is shown that the circumferential compliance and burst strength of vascular grafts can be analytically predicted by knowing the elastic and yield material properties accurately, without needing to actually test the graft under radial pressure. This is a major advantage which can aid in the design and tailoring of vascular grafts.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Ibuprofen, a nonsteroidal antiinflammatory drug, widely used as antipyretic, antiinflammatory, and analgesic agent and for therapy of arthritis, exerts a dose-dependent constriction of the ductus ...arteriosus in newborn lambs. Two intravenous preparations, namely ibuprofen lysine and ibuprofen-THAM, have been studied in preterm newborns with patent ductus arteriosus. Clinical trials have compared IV ibuprofen to placebo, or to indomethacin. Pharmacodynamic effects of this drug before and after its administration have also been evaluated. Compared with placebo, IV ibuprofen effectively closed PDA with minimal effect on renal function. One study using intravenous ibuprofen-THAM showed decreased renal function and increased risk of NEC and PPHN. Compared with indomethacin, IV ibuprofen lysine exerted similar efficacy (75% to 93% closure). However, indomethacin increased abnormal renal function and decreased mesenteric and cerebral blood flow and bio-energetics. Two clinical trials showed that ibuprofen did not reduce the incidence of intraventricular hemorrhage compared with placebo. The drug has prolonged elimination (plasma half-life = ca 23 hours), suggesting that once daily dosing is appropriate. Dose finding studies indicate that a starting dose of 10 mg/kg followed by 5 mg/kg/d for 2 more days provides optimal efficacy with the least adverse effects. Neonatal data on ibuprofen and indomethacin indicate that, on the first day of life when IVH prevention is desired, indomethacin and not ibuprofen should be used since ibuprofen has no effect on IVH risk. On or after the second day of postnatal life, when early or therapeutic PDA closure is needed, ibuprofen and not indomethacin is probably the first choice due to its better adverse event profile.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Introduction
The Multidimensional Weight Locus of Control Scale (MWLCS) measures a person’s beliefs regarding the locus of control or lack of locus of control over his/her body weight.
Purpose
We aim ...to evaluate the factorial structure and psychometric properties of the MWLCS with Spanish normal weight, overweight and obese samples.
Methods
The research was carried out in two different studies. The first included a sample of 140 normal weight participants, selected out of a 274 sample recruited with an online survey. Study 2 was carried out in a sample of 633 participants recruited from the PREDIMED-Plus study. Out of them, 558 participants fulfilled the weight criteria and were categorized into: overweight (BMI 25 − < 29.99;
N
= 170), obese class I (BMI 30 − < 34.99;
N
= 266), and obese class II (BMI 35 − < 39.99;
N
= 122). Exploratory (EFA) and confirmatory (CFA) factor analyses were used to evaluate the factor structure of the MWLCS, and reliabilities and Spearman’s correlations were estimated. Invariance measurement was tested across the three subgroups of weight in Study 2.
Results
A three-factor structure indicating weight locus of control factors (internal, chance, and powerful others) was supported, both via EFA in the normal weight sample and CFA in the overweight and obese samples. In the normal weight sample, the powerful others dimension was positively related to BMI and the dimensions of the Dutch Eating Behaviors Questionnaire. Additionally, the scale showed evidence of scalar invariance across the groups with different weight conditions.
Conclusions
This scale seems to be a psychometrically appropriate instrument and its use is highly recommended when designing interventions for overweight or obese individuals.
Level of evidence
Level V, descriptive study.
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FZAB, GEOZS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Objectives
We tested the effects of a weight-loss intervention encouraging energy-reduced MedDiet and physical activity (PA) in comparison to
ad libitum
MedDiet on COVID-19 incidence in older adults.
...Design
Secondary analysis of PREDIMED-Plus, a prospective, ongoing, multicentre randomized controlled trial.
Setting
Community-dwelling, free-living participants in PREDIMED-Plus trial.
Participants
6,874 Spanish older adults (55–75 years, 49% women) with overweight/obesity and metabolic syndrome.
Intervention
Participants were randomised to Intervention (IG) or Control (CG) Group. IG received intensive behavioural intervention for weight loss with an energy-reduced MedDiet intervention and PA promotion. CG was encouraged to consume
ad libitum
MedDiet without PA recommendations.
Measurements
COVID-19 was ascertained by an independent Event Committee until December 31, 2021. COX regression models compared the effect of PREDIMED-Plus interventions on COVID-19 risk.
Results
Overall, 653 COVID-19 incident cases were documented (IG:317; CG:336) over a median (IQR) follow-up of 5.8 (1.3) years (inclusive of 4.0 (1.2) years before community transmission of COVID-19) in both groups. A significantly lowered risk of COVID-19 incidence was not evident in IG, compared to CG (fully-adjusted HR (95% CI): 0.96 (0.81,1.12)).
Conclusions
There was no evidence to show that an intensive weight-loss intervention encouraging energy-reduced MedDiet and PA significantly lowered COVID-19 risk in older adults with overweight/ obesity and metabolic syndrome in comparison to
ad libitum
MedDiet. Recommendations to improve adherence to MedDiet provided with or without lifestyle modification suggestions for weight loss may have similar effects in protecting against COVID-19 risk in older adults with high cardiovascular risks.
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