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Medicina Intensiva Jun 2024Central venous-arterial PCO to arterial-central venous O content ratio (PCO/CO) is commonly used as a surrogate for respiratory quotient (RQ) and tissue oxygenation....
Lack of correlation between central venous minus arterial PCO to arterial minus central venous O content ratio and respiratory quotient in patients with septic shock: A prospective observational study.
OBJECTIVE
Central venous-arterial PCO to arterial-central venous O content ratio (PCO/CO) is commonly used as a surrogate for respiratory quotient (RQ) and tissue oxygenation. Although PCO/CO might be associated with hyperlactatemia and outcome, neither the interchangeability with RQ nor the correlation with conclusive variables of anaerobic metabolism has never been demonstrated in septic shock. Our goal was to compare PCO/CO and RQ in patients with septic shock.
DESIGN
Prospective, observational study.
SETTING
Two adult ICUs.
PATIENTS
Forty-seven patients with septic shock on mechanical ventilation with stable respiratory settings and vasopressor dose after initial resuscitation.
INTERVENTIONS
None.
MAIN VARIABLES OF INTEREST
We measured arterial and central venous gases, Hb, and OHb. PCO/CO and the ratio of central venous-arterial CO content to arterial-central venous O content (CCO/CO) were calculated. RQ was determined by indirect calorimetry.
RESULTS
PCO/CO and CCO/CO were not correlated with RQ (R = 0.01, P = 0.50 and R = 0.01, P = 0.58, respectively), showing large bias and wide 95 % limits of agreement with RQ (1.09, -1.10-3.27 and 0.42, -1.53-2.37). A multiple linear regression model showed Hb, and central venous PCO and OHb, but not RQ, as PCO/CO determinants (R = 0.36, P = 0.0007).
CONCLUSIONS
In patients with septic shock, PCO/CO did not correlate with RQ and was mainly determined by factors that modify the dissociation of CO from Hb. PCO/CO seems to be a poor surrogate for RQ; therefore, its values should be interpreted with caution.
PubMed: 38909012
DOI: 10.1016/j.medine.2024.06.005 -
Free Radical Biology & Medicine Jun 2024The skin is made up of different layers with various gradients, which maintain a complex microenvironment, particularly in terms of oxygen levels. However, all types of... (Review)
Review
The skin is made up of different layers with various gradients, which maintain a complex microenvironment, particularly in terms of oxygen levels. However, all types of skin cells are cultured in conventional incubators that do not reproduce physiological oxygen levels. Instead, they are cultured at atmospheric oxygen levels, a condition that is far removed from physiology and may lead to the generation of free radicals known to induce skin ageing. This review aims to summarize the current literature on the effect of physiological oxygen levels on skin cells, highlight the shortcomings of current in vitro models, and demonstrate the importance of respecting skin oxygen levels. We begin by clarifying the terminology used about oxygen levels and describe the specific distribution of oxygen in the skin. We review and discuss how skin cells adapt their oxygen consumption and metabolism to oxygen levels environment, as well as the changes that are induced, particularly, their redox state, life cycle and functions. We examine the effects of oxygen on both simple culture models and more complex reconstructed skin models. Finally, we present the implications of oxygen modulation for a more therapeutic approach.
PubMed: 38908804
DOI: 10.1016/j.freeradbiomed.2024.06.015 -
Plant Physiology and Biochemistry : PPB Jun 2024Arsenic (As) is an acute toxic metalloid that affects plant growth and development. As is found in the environment in organic and inorganic forms, but arsenite As(III)... (Review)
Review
Arsenic (As) is an acute toxic metalloid that affects plant growth and development. As is found in the environment in organic and inorganic forms, but arsenite As(III) and arsenate As(V) are the most prevalent forms that negatively impact the plants. Roots exposed to As can easily absorb it mainly through transporters that carry vital mineral nutrients. As reach the food chain via crops irrigated with As-polluted water and exerts a negative impact. Even at low levels, As exposure disrupts the regular functioning of plants by generating a high level of reactive oxygen species (ROS) results into oxidative damage, and disruption of redox system. Plants have built-in defence mechanisms to combat this oxidative damage. The development of a food crop with lower As levels is dependent upon understanding the molecular process of As detoxification in plants, which will help reduce the consumption of As-contaminated food. Numerous genes in plants that may provide tolerance under hazardous conditions have been examined using genetic engineering techniques. The suppression of genes by RNA interference (RNAi) and CRISPR-Cas 9 (CRISPR associated protein 9) technology revealed an intriguing approach for developing a crop that has minimal As levels in consumable portions. This study aims to present current information on the biochemical and molecular networks associated with As uptake, as well as recent advances in the field of As mitigation using exogenous salicylic acid (SA), Serendipita indica and biotechnological tools in terms of generating As-tolerant plants with low As accumulation.
PubMed: 38908350
DOI: 10.1016/j.plaphy.2024.108848 -
The Journal of Nutrition, Health & Aging Jun 2024There is a lack of consensus about the operationalization of vitality, which is one of the intrinsic capacity (IC) domains. In particular, no study has investigated...
BACKGROUND
There is a lack of consensus about the operationalization of vitality, which is one of the intrinsic capacity (IC) domains. In particular, no study has investigated whether cardiorespiratory fitness (CRF) can be considered a vitality indicator.
OBJECTIVE
To examine whether vitality is the upstream domain of IC, and establish the validity of CRF as a vitality indicator, using maximal oxygen consumption (VO max) as a representative.
METHODS
561 older adults from a longitudinal cohort study were included. Variables under consideration were VO max, other IC domains, instrumental activities of daily living (IADL), and handgrip strength, which was considered an already validated indicator of vitality. Using handgrip strength as the reference point, path analyses were performed to examine whether VO max followed a similar hierarchical structure in predicting change in IADL difficulty through other IC domains.
RESULTS
The mean age of the participants was 75.5 years. The path model in which vitality was measured by VO max demonstrated adequate fit, which was similar to the model in which vitality was measured by handgrip strength. Regarding the path coefficients, the model using VO max demonstrated significant total and indirect effects. Notably, the indirect effect was due to the locomotor domain (standardized coefficient = -0.148, p < .001), but not the cognitive or psychological domain.
CONCLUSION
Vitality is the upstream domain of IC. VO max can be considered an indicator to operationalize the vitality concept.
PubMed: 38908298
DOI: 10.1016/j.jnha.2024.100300 -
Nature Communications Jun 2024The introduction of single-atom catalysts (SACs) into Fenton-like oxidation promises ultrafast water pollutant elimination, but the limited access to pollutants and...
The introduction of single-atom catalysts (SACs) into Fenton-like oxidation promises ultrafast water pollutant elimination, but the limited access to pollutants and oxidant by surface catalytic sites and the intensive oxidant consumption still severely restrict the decontamination performance. While nanoconfinement of SACs allows drastically enhanced decontamination reaction kinetics, the detailed regulatory mechanisms remain elusive. Here, we unveil that, apart from local enrichment of reactants, the catalytic pathway shift is also an important cause for the reactivity enhancement of nanoconfined SACs. The surface electronic structure of cobalt site is altered by confining it within the nanopores of mesostructured silica particles, which triggers a fundamental transition from singlet oxygen to electron transfer pathway for 4-chlorophenol oxidation. The changed pathway and accelerated interfacial mass transfer render the nanoconfined system up to 34.7-fold higher pollutant degradation rate and drastically raised peroxymonosulfate utilization efficiency (from 61.8% to 96.6%) relative to the unconfined control. It also demonstrates superior reactivity for the degradation of other electron-rich phenolic compounds, good environment robustness, and high stability for treating real lake water. Our findings deepen the knowledge of nanoconfined catalysis and may inspire innovations in low-carbon water purification technologies and other heterogeneous catalytic applications.
PubMed: 38906879
DOI: 10.1038/s41467-024-49605-2 -
Journal of Controlled Release :... Jun 2024To build a smart system in response to the variable microenvironment in infected diabetic wounds, a multifunctional wound dressing was constructed by co-incorporating...
To build a smart system in response to the variable microenvironment in infected diabetic wounds, a multifunctional wound dressing was constructed by co-incorporating glucose oxidase (GOx) and a pH-responsive self-assembly CuSe-BSA nanozyme into a dual-dynamic bond cross-linked hydrogel (OBG). This composite hydrogel (OBG@CG) can adhere to the wound site and respond to the acidic inflammatory environment, initiating the GOx-catalyzed generation of HO and the self-assembly activated peroxidase-like property of CuSe-BSA nanozymes, resulting in significant hydroxyl radical production to attack the biofilm during the acute infection period and alleviate the high-glucose microenvironment for better wound healing. During the wound recovery phase, CuSe-BSA aggregates disassembled owing to the elevated pH, terminating catalytic reactive oxygen species generation. Simultaneously, Cu released from the CuSe-BSA not only promotes the production of mature collagen but also enhances the migration and proliferation of endothelial cells. RNA-seq analysis demonstrated that OBG@CG exerted its antibacterial property by damaging the integrity of the biofilm by inducing radicals and interfering with the energy supply, along with destroying the defense system by disturbing thiol metabolism and reducing transporter activities. This work proposes an innovative glucose consumption strategy for infected diabetic wound management, which may inspire new ideas in the exploration of smart wound dressing.
PubMed: 38906418
DOI: 10.1016/j.jconrel.2024.06.040 -
Chemosphere Jun 2024This study presents the successful synthesis of Magnesium-aluminum layered double hydroxide composite phosphate-modified hydrothermal biochar for efficient removal of...
Efficient enrichment of uranium (VI) in aqueous solution using magnesium-aluminum layered double hydroxide composite phosphate-modified hydrothermal biochar: Mechanism and adsorption.
This study presents the successful synthesis of Magnesium-aluminum layered double hydroxide composite phosphate-modified hydrothermal biochar for efficient removal of U(VI) from aqueous solutions. A novel synthesis approach involving phosphate thermal polymerization-hydrothermal method was employed, deviating from conventional pyrolysis methods, to produce hydrothermal biochar. The combination of solvent thermal polymerization technique with hydrothermal process facilitated efficient loading of layered double hydroxide (LDH) components onto the biochar surface, ensuring simplicity, low energy consumption and enhanced modifiability. Bamboo waste was utilized as the precursor for biochar, highlighting its superior green and sustainable characteristics. Additionally, this study elucidated the interactions between phosphate-modified hydrothermal biochar and LDH components with U(VI). Physicochemical analysis demonstrated that the composite biochar possessed a high surface area and abundant oxygen-containing functional groups. XPS and FTIR analyses confirmed the efficient adsorption of U(VI), attributed to chelation interactions between phosphate groups, magnesium hydroxyl groups, hydroxyl groups and U(VI), as well as the co-precipitation of U(VI) with multi-hydroxyl aluminum cations captured by LDH. The composite biochar reached adsorption equilibrium with U(VI) within 80 min and exhibited excellent fitting to the pseudo-second-order kinetic model and Langmuir model. Under conditions of pH = 4 and 298 K, it displayed significantly high maximum adsorption capacity of approximately 388.81 mg g⁻, surpassing untreated biochar by 17-fold. The adsorption process was found to be endothermic and spontaneous and even after five consecutive adsorption-desorption cycles, the removal efficiency of U(VI) remained stable at 75.46%. These findings underscore the promising application prospects of Magnesium-aluminum layered double hydroxide composite phosphate-modified hydrothermal biochar in efficiently separating U(VI) from uranium-containing wastewater, emphasizing its environmental and economic value.
PubMed: 38906190
DOI: 10.1016/j.chemosphere.2024.142667 -
Bulletin of Experimental Biology and... Jun 2024We studied the effectiveness of Xe/O mixture inhalation (30% Xe and 70% O, 20 min for 5 days) in a model of experimental thromboplastin pneumonitis. Inhalation of the...
We studied the effectiveness of Xe/O mixture inhalation (30% Xe and 70% O, 20 min for 5 days) in a model of experimental thromboplastin pneumonitis. Inhalation of the studied mixture decreased the intensity of the inflammatory process in the lung tissue assessed by the temperature response of animals, changed lung weight and lung weight coefficient. At acute stage of pneumonitis, an increase in xenon consumption was recorded due to its retention in the gas exchange zone and a natural decrease in oxygen consumption due to partial alveolar/capillary block. The formation of pneumonitis was accompanied by a pronounced procoagulant shift in the regulation system of the aggregate state of blood. The Xe/O inhalations ensured physiologically optimal levels of prothrombin and activated partial thromboplastin time against the background of a moderate decrease in fibrinogen level throughout the experiment. At the same time, the activity of the natural anticoagulant antithrombin III increased from day 5 to day 14.
PubMed: 38904932
DOI: 10.1007/s10517-024-06098-9 -
BioRxiv : the Preprint Server For... May 2024Pathogenic variants in were recently linked to a limb-girdle muscular dystrophy (LGMD) phenotype. The protein product HMG CoA reductase (HMGCR) catalyzes a key...
Pathogenic variants in were recently linked to a limb-girdle muscular dystrophy (LGMD) phenotype. The protein product HMG CoA reductase (HMGCR) catalyzes a key component of the cholesterol synthesis pathway. The two other muscle diseases associated with HMGCR, statin-associated myopathy (SAM) and autoimmune anti-HMGCR myopathy, are not inherited in a Mendelian pattern. The mechanism linking pathogenic variants in with skeletal muscle dysfunction is unclear. We knocked down in mouse skeletal myoblasts, knocked down in Drosophila, and expressed three pathogenic variants (c.1327C>T, p.Arg443Trp; c.1522_1524delTCT, p.Ser508del; and c.1621G>A, p.Ala541Thr) in knockdown mouse myoblasts. deficiency was associated with decreased proliferation, increased apoptosis, and impaired myotube fusion. Transcriptome sequencing of knockdown versus control myoblasts revealed differential expression involving mitochondrial function, with corresponding differences in cellular oxygen consumption rates. Both ubiquitous and muscle-specific knockdown of in Drosophila led to lethality. Overexpression of reference cDNA rescued myotube fusion in knockdown cells, whereas overexpression of the pathogenic variants of cDNA did not. These results suggest that the three HMGCR-related muscle diseases share disease mechanisms related to skeletal muscle development.
PubMed: 38903061
DOI: 10.1101/2024.05.06.591934 -
Journal of Thermal Biology Jun 2024The relationship between behavioral thermoregulation and physiological recovery following exhaustive exercise is not well understood. Behavioral thermoregulation could...
The relationship between behavioral thermoregulation and physiological recovery following exhaustive exercise is not well understood. Behavioral thermoregulation could be beneficial for exercise recovery; for example, selection of cooler temperatures could reduce maintenance metabolic cost to preserve aerobic scope for recovery cost, or selection of warmer temperatures could accelerate recovery of exercise metabolites. While post-exercise behavioral thermoregulation has been observed in lizards and frogs, little is known about its importance in fish. We examined the influence of post-exercise recovery temperature on metabolic rate, thermal preference, and metabolite concentrations in juvenile brook char (Salvelinus fontinalis). Fish were acclimated to and exercised at 15 °C, then recovered at either 15 °C or 10 °C while their metabolic rate was measured via respirometry. Metabolite concentrations were measured in fish after exercise at 15 °C and recovery under one of three thermal treatments (to simulate various behavioral thermoregulation scenarios): (i) 6 h recovery at 15 °C, (ii) 6 h recovery at 10 °C, or (iii) 3 h recovery at 10 °C followed by 3 h recovery at 15 °C. Thermal preference was quantified using a static temperature preference system (15 °C vs. 10 °C). Metabolic rates returned to resting faster at 10 °C compared with 15 °C, although at 10 °C there was a tradeoff of delayed metabolite recovery. Specifically, post-exercise plasma osmolality, plasma lactate, and muscle lactate remained elevated for the entire period in fish recovering at 10 °C, whereas these parameters returned to resting levels by 6 h in fish from the other two recovery groups. Regardless, fish did not exhibit clear behavioral thermoregulation (i.e., fish overall did not consistently prefer one temperature) to prioritize either physiological recovery process. The advantage of metabolic rate recovery at cooler temperatures may balance against the advantage of metabolite recovery at warmer temperatures, lessening the usefulness of behavioral thermoregulation as a post-exercise recovery strategy in fish.
PubMed: 38901397
DOI: 10.1016/j.jtherbio.2024.103888