Oxygenation Status Research Articles

Chewing-Activated TRPV4/PIEZO1-HIF-1α-Zn Axes in a Rat Periodontal Complex.

The upstream mechanobiological pathways that regulate the downstream mineralization rates in periodontal tissues are limitedly understood. Herein, we spatially colocalized and correlated compression and tension strain profiles with the expressions of mechanosensory ion channels (MS-ion) TRPV4 and PIEZO1, biometal zinc, mitochondrial function marker (MFN2), cell senescence indicator (p16), and oxygen status marker hypoxia-inducible factor-1α (HIF-1α) in rats fed hard and soft foods. The observed zinc and related cellular homeostasis in vivo were ascertained by TRPV4 and PIEZO1 agonists and antagonists on human periodontal ligament fibroblasts ex vivo. Four-week-old male Sprague-Dawley rats were fed hard (n = 3) or soft (n = 3) foods for 4 wk (in vivo). Significant changes in alveolar socket and root shapes with decreased periodontal ligament space and increased cementum volume fraction were observed in maxillae on reduced loads (soft food). Reduced loads impaired distally localized compression-stimulated PIEZO1 and mesially localized tension-stimulated TRPV4, decreased mitochondrial function (MFN2), and increased cell senescence in mesial and distal periodontal regions. The switch in HIF-1α from hard food-distal to soft food-mesial indicated a plausible effect of shear-regulated blood and oxygen flows in the periodontal complex. Blunting or activating TRPV4 or PIEZO1 MS-ion channels by channel-specific antagonists or agonists in human periodontal ligament fibroblast cultures (in vitro) indicated a positive correlation between zinc levels and zinc transporters but not with MS-ion channel expressions. The effects of reduced chewing loads in vivo were analogous to TRPV4 and PIEZO1 antagonists in vitro. Study results collectively illustrated that tension-induced TRPV4 and compression-induced PIEZO1 activations are necessary for cell metabolism. An increased hypoxic state with reduced functional loads can be a conducive environment for cementum growth. From a practical standpoint, dose rate-controlled loads can modulate tension and compression-specific MS-ion channel activation, cellular zinc, and HIF-1α transcription. These mechanobiochemical events indicate the plausible catalytic role of biometal zinc in mineralization, periodontal maintenance, and dentoalveolar joint function.

Spin Magnetic Effect Activate Dual Site Intramolecular O─O Bridging for Nickel-Iron Hydroxide Enhanced Oxygen Evolution Catalysis.

The oxygen evolution reaction (OER) involves the recombination of diamagnetic hydroxyl (OH) or water (H2O) into the paramagnetic triplet state of oxygen (O2). The spin conservation of oxygen intermediates plays a crucial role in OER, however, research on spin dynamics during the catalytic process remains in its early stages. Herein, β-Ni(OH)2 and Fe-doped β-Ni(OH)2 (Ni5Fe1(OH)2) are utilized as model catalysts to understand the mechanism of spin magnetic effects at iron (III) sites during OER. Combined with magnetic characterization, it is founded that the introduction of Fe transforms the antiferromagnetic Ni(OH)2 into a ferromagnetic material. Testing the magnetic response of the catalyst under an external magnetic field, the OER activity of Ni5Fe1(OH)2 is significantly enhanced in comparison to Ni(OH)2. This improvement is likely due to the introduction of iron sites, which promote spin magnetic effects and enhance reaction kinetics, thereby increasing catalytic efficiency. Combining experimental and theoretical characterization, it is discovered that the iron sites accelerate the formation of heterogeneous dual-site O─O bridging, represented as ─Ni─O─O─Fe─, thereby effectively enhancing the kinetics of the OER reaction. This study provides a magnetic perspective on the structure-function relationship of magnetic iron-based catalysts and has significant implications for the design of new catalysts.

Guided Multispectral Optoacoustic Tomography for 3D Imaging of the Murine Colon.

Multispectral optoacoustic tomography is a promising medical imaging modality that combines light and sound to provide molecular imaging information at depths of several centimeters, based on the optical absorption of endogenous chromophores, such as hemoglobin. Assessment of inflammatory bowel disease has emerged as a promising clinical application of optoacoustic tomography. In this context, preclinical studies in animal models are essential to identify novel disease-specific imaging biomarkers and understand findings from emerging clinical pilot studies, however to-date, these studies have been limited by the precise identification of the bowel wall. Herein, a transrectal-absorber guide is applied, serving as a high-contrast landmark for 3D optoacoustic tomography of the colon. This study shows that guided multispectral optoacoustic tomography is able to measure changes in blood oxygenation status over the course of acute, chemically-induced colitis in mice and correlates with standard disease activity scores. This novel approach depicts intestinal hemoglobin composition non-invasively during murine inflammation. These results underscore the potential for optoacoustic imaging in translational inflammatory bowel disease research.

A novel small RNA regulates Locus of Enterocyte Effacement and site-specific colonization of enterohemorrhagic Escherichia coli O157:H7 in gut

Enterohemorrhagic Escherichia coli (EHEC) is a contagious foodborne pathogen that specifically colonizes the human large intestine, which is regulated by different environmental stimuli within the gut. Transcriptional regulation of EHEC virulence and infection has been extensively studied, while the posttranscriptional regulation of these processes by small RNAs (sRNAs) remains not fully understood. Here we present a virulence-regulating pathway in EHEC O157:H7, in which the sRNA EvrS binds to and destabilizes the mRNA of Z2269, a novel transcriptional regulator. In turn, Z2269 indirectly activates the expression of LEE (locus of enterocyte effacement) pathogenicity island through the master regulator Ler. Importantly, the expression of EvrS is modulated by environmental oxygen levels. EvrS also exhibits lower expression in the colon compared to the ileum, influencing the site-specific colonization of EHEC O157:H7 in mice. These results indicate that the oxygen status within the intestine may regulate the expression of EvrS, thereby modulating virulence factors of EHEC and contributing to successful infection in vivo. This study has broader implications for understanding sRNA functions in spatiotemporal virulence control of EHEC and may provide novel strategies to prevent EHEC infections.

Modulation of the Oxygenation State and Intracellular pH of Erythrocytes by Inositol-Trispyrophosphate Investigated by 31P NMR Study of 2,3-DPG.

The hypoxic microenvironment is crucial for tumour cell growth and invasiveness. Tumour tissue results from adaptation to reduced oxygen availability. Hypoxia first activates pro-angiogenic signals for alleviation. Pathologic, tumour angiogenesis maintains hypoxia, impairing treatment outcomes. Vessel normalisation requires physioxia. Oxygen delivery by red blood cell (RBC) carrying haemoglobin (Hb) is enhanced by myo-inositol trispyrophosphate (ITPP), an effector of oxygen transport by RBCs. Altering glycolytic activity, it lowers intracellular pH and increases oxygen release from Hb. 31P NMR tracking of 2,3-diphosphoglycerate (2,3-DPG), allosteric effector of Hb and non-penetrating anion in RBCs, reports on erythrocytes internal environment. 31P resonances of 2,3-DPG are pH-sensitive, their positions indicate the oxygenation state of RBCs and interactions with effectors such as ITPP. Here we show invitro and invivo, that modifying Hb activity through band-3 anion transporter, ITPP enhances oxygen release and controls RBC internal pH. Its blood availability validates applicability of ITPP-based strategies.

Influence of the Mechanosynthesis Duration on the Structural, Electronic, and Electrochemical Characteristics of SiO2/TiO2 Nanocomposite

Abstract The study investigated of the duration effect of the high-energy machining in a vibrating mill on the performance of lithium power source cathode material based on SiO2/TiO2 nanopowder. The relationship between the electronic structure, crystalline parameters, morphological features of the nanopowder mixture, and the electrochemical characteristics of the prototype battery with a cathode based on it was established. Combination of scanning electron microscopy, X-ray diffraction, ultra-soft X-ray emission spectroscopy, galvanostatic, and potentiodynamic analysis was used for materials characterization. It was concluded that SiO2/TiO2 nanopowder mixture after mechanosynthesis treatment during 5 minutes reveals most promising electrochemical characteristics in terms of possible application as primary and secondary power sources. This result is caused by the desorption of absorbed moisture, the grinding of the initial agglomerates, and the formation of a high charge state of oxygen due to the creation of a weak π-bond between the nanoparticles surface of both oxides during such a brief treatment. Further increase of processing duration promotes the agglomeration of the nanocomposite and a significant reduction in the electrochemical characteristics of the lithium power source.

Unraveling energetics and states of adsorbing oxygen species with MoS2 for modulated work function.

MoS2 and related transition metal dichalcogenides (TMDs) have recently been reported as having extensive applications in nanoelectronics and catalysis because of their unique physical and chemical properties. However, one practical challenge for MoS2-based applications arises from the easiness of oxygen contamination, which is likely to degrade performance. To this end, understanding the states and related energetics of adsorbed oxygen is critical. Herein, we identify various states of oxygen species adsorbed on the MoS2 surface with first-principles calculations. We reveal a "dissociative" mechanism through which a physisorbed oxygen molecule trapped at a sulfur vacancy can split into two chemisorbed oxygen atoms, namely a top-anchoring oxygen and a substituting oxygen, both of which show no adsorbate induced states in the bandgap. The electron and hole masses show an asymmetric effect in response to oxygen species with the hole mass being more sensitive to oxygen content due to a strong hybridization of oxygen states in the valence band edge of MoS2. Alteration of oxygen content allows modulation of the work function up to 0.5 eV, enabling reduced Schottky barriers in MoS2/metal contact. These results show that oxygen doping on MoS2 is a promising method for sulfur vacancy healing, carrier mass controlling, contact resistance reduction, and anchoring of surface electron dopants. Our study suggests that tuning the chemical composition of oxygen is viable for modulating the electronic properties of MoS2 and likely other chalcogen-incorporated TMDs, which offers promise for new optoelectronic applications.

SUCCESSFUL MANAGEMENT OF PATIENT OF INHALATIONAL INJURY INDUCED ARDS

Background: Involvement in fire accidents can be associated with inhalational injury resulting from inhalation of smoke or chemical products of combustion, which can further lead to ALI and ARDS Here we present a case of successful management of a 22 year old patient who suffered from CO poisoning with inhalational injury induced ARDS. Case Description: A 22-year-old male came in with alleged history of involvement in a fire accident at a hotel. Initially suspected of having CO poisoning along with severe acute lung injury and acute respiratory distress syndrome. Patient was initially managed on HFNC but shifted to IMV and managed according to ARDS protocol. Over a period of 12 days, we were able to successfully treat him and move him out of the ICU. Discussion and Conclusion: Treatment of CO poisoning is established as immediate removal of victim from the exposure and administration of high flow 100% O2. Since, there is no single management protocol for inhalational injury, this case was treated as per ARDS management protocol with bronchoscopy and bronchoalveolar lavage, which helped in significantly improving the patientÂ’s oxygenation status and earlier recovery than expected. Hence, we hypothesize that employment of early bronchoscopy and bronchoalveolar lavage helps in accelerating the recovery of patients suffering from inhalational injury induced ARDS.

Characterization of an Unexpected μ3 Adsorption of Molecular Oxygen on Ag(100) with Low-Temperature STM.

Precise description of the interaction between molecular oxygen and metal surfaces is one of the most challenging topics in quantum chemistry. In this work, we use low-temperature scanning tunneling microscopy (STM) to identify and characterize an adsorption state of molecular oxygen that coordinates to three Ag atoms (μ3) on Ag(100). Surprisingly, μ3-O2 cannot be identified as a stable configuration with generalized gradient approximation (GGA)-level density functional theory (DFT) calculations. Through inelastic electron tunneling spectroscopy (IETS), we identify three vibrational modes of individual μ3-O2 and assign them to out-of-plane hindered rotation (HR) at 38.0 meV, in-plane HR at 32.4 meV, and in-plane hindered translation (HT) at 22.0 meV. We determine the barrier for rotational isomerization of μ3-O2 to be 69.3 meV from tunneling electrons-induced rotations. The inability of theory to predict the experiment stems most likely from self-interaction errors inherent to GGA-DFT, which leads to an inaccurate description of localized charges. We speculate that the μ3-O2 configuration represents a formal molecular oxygen anion and assign the ±11 meV excitation in the IETS to a transition between spin-orbit states of the surface-bound anion.

Assessing Wound Healing in Vivo Using a Dual-Function Phosphorescent Probe Sensitive to Tissue Oxygenation and Regenerating Collagen.

Levels of tissue oxygenation and collagen regeneration are critical indicators in the early evaluation of wound healing. Traditionally, these factors have been assessed using separate instruments and different methodologies. Here, we adopt the spatially averaged phosphorescence lifetime approach using ReI-diimine complexes (ReI-probe) to enable simultaneous quantification of these two critical factors in healing wounds. The topically applied, biocompatible ReI-probe penetrates wound tissue effectively and selectively binds to collagen fibers. During collagen regeneration, the phosphorescence lifetimes of the collagen-bound probe significantly extend from an initial range of 4.5-6.5 μs on day 0 to 5.5-8.5 μs by day 7. Concurrently, unbound probes in the tissue interstitial spaces exhibit a phosphorescence lifetime of 4.5-5.2 μs, revealing the oxygenation states. Using phosphorescence lifetime imaging microscopy (PLIM) and a frequency domain phosphorescence lifetime measurement (FD-PLM) system, we validated the dual-functionality of this ReI-probe in differentiating healing stages in chronic wounds. With its noninvasive, quantitative measurement capabilities for cutaneous wounds, this ReI-probe-based approach offers promising potential for early wound healing diagnosis.

A NIRS-Based Technique for Monitoring Brain Tissue Oxygenation in Stroke Patients.

Stroke is a global health issue caused by reduced blood flow to the brain, which leads to severe motor disabilities. Measuring oxygen levels in the brain tissue is crucial for understanding the severity and evolution of stroke. While CT or fMRI scans are preferred for confirming a stroke due to their high sensitivity, Near-Infrared Spectroscopy (NIRS)-based systems could be an alternative for monitoring stroke evolution. This study explores the potential of fNIRS signals to assess brain tissue in chronic stroke patients along with rehabilitation therapy. To study the feasibility of this proposal, ten healthy subjects and three stroke patients participated. For signal acquisition, two NIRS sensors were placed on the forehead of the subjects, who were asked to remain in a resting state for 5 min, followed by a 30 s motor task for each hand, which consists of opening and closing the hand at a steady pace, with a 1 min rest period in between. Acomplete protocol for placing sensors and a signal processing algorithm are proposed. In healthy subjects, a measurable change in oxygen saturation was found, with statistically significant differences (females p = 0.016, males p = 0.005) between the resting-state and the hand movement conditions. This work showed the feasibility of the complete proposal, including the NIRS sensor, the placement, the tasks protocol, and signal processing, for monitoring the state of the brain tissue cerebral oxygenation in stroke patients undergoing rehabilitation therapy. Thus this is a non-invasive barin assessment test based on fNIRS with the potential to be implemented in non-controlled clinical environments.

Charge Transfer‐Driven Conversion of Molecular Oxygen to Doublet State on Vanadium Diselenide (VSe2) Surface at Room Temperature

AbstractOxygen in the excited state is essential for organic synthesis and medical treatment. Herein, a novel phenomenon is reported in which the magnetic ground state of molecular oxygen undergoes a transition at room temperature from S = 1 to S = 1/2, corresponding to the transition of O2 from a triplet to a doublet state after stable physical adsorption on the defect‐free surface of bulk VSe2. This density functional theory (DFT) calculations demonstrate the stable physical adsorption of O2 on both 1T‐ and 2H‐VSe2 surfaces without further decomposition. Electron spin resonance (ESR) measurements confirm the spin state transition. Theoretical simulations reveal the charge transfer from entangled V‐3d and Se‐4p bands to oxygen as the leading cause of the spin state transition. This mechanism has not been previously proposed and offers multiple potential applications, from organic synthesis to medicine. Moreover, this approach can be extended to reveal new aspects of known catalytic materials and to design novel catalysts.

The Prognostic Value of the Muscle Regional Oxygen Saturation Index in Patients with Acute Respiratory Distress Syndrome.

Background: Impaired systemic tissue oxygenation and microvascular perfusion are associated with adverse outcomes in patients with acute respiratory distress syndrome (ARDS). Tissue oxygenation and microvascular reactivity, assessed by using near-infrared spectroscopy (NIRS), are correlated with disease severity in critically ill populations. This study aimed to detect alterations in these factors and their ability to predict outcomes in patients with ARDS. Methods: We performed NIRS measurements on the first (Day 1) and third (Day 3) days after ARDS diagnosis in 29 patients. We recorded the baseline forearm muscle oxygen saturation (StO2) and calculated the deoxygenation slope (Deoxy) and reoxygenation (Reoxy) slope. We divided the subjects into 28-day survival and non-survival subgroups to compare microcirculatory and oxygenation status differences. Results: The Day 1 StO2 values were significantly higher for the survival subgroup (60.1 ± 13.5%) than the non-survival subgroup (47.2 ± 6.9%) (p = 0.025). The ROC curve showed that Day 1 StO2 was a significant predictor of 28-day mortality (p = 0.025). There was no significant difference between the Deoxy and Reoxy slopes of the two groups (p > 0.05). The ROC of the Day 1 Reoxy slope for survival prediction (AUC0.74) was not statistically significant (p = 0.074). Conclusions: Our study showed poor survival outcomes in patients who had lower skeletal muscle StO2 values in early-stage ARDS. NIRS measurements may provide prognostic value for the survival outcomes in patients with this syndrome.

Fluid Management in Critical Care: New Insights Into Optimal Fluid Therapy.

Fluid management is a crucial critical care component, influencing outcomes such as organ function, renal integrity, and survival in critically ill patients. Recent evidence suggests that balanced crystalloids may offer advantages over isotonic saline, particularly in reducing the risk of acute kidney injury (AKI) and other complications. This study aimed to evaluate the impact of balanced crystalloids versus isotonic saline on clinical outcomes in the intensive care unit (ICU), focusing on AKI, renal replacement therapy (RRT), and mortality. The study also assessed the role of fluid restriction in specific patient populations, including those with acute respiratory distress syndrome (ARDS), sepsis, and heart failure. A retrospective cohort study included 600 adult patients admitted to the ICU who received fluid therapy between January 2023 and January 2024. Patients were categorized into two groups based on the type of fluid received: 300 patients received balanced crystalloids and 300 received isotonic saline. Outcomes of interest included the incidence of AKI, the need for RRT, overall ICU mortality, oxygenation status (PaO2/FiO2 ratio), duration of mechanical ventilation, cumulative fluid balance, and length of ICU stay. Statistical analyses included multivariate logistic regression to adjust for potential confounders. The incidence of AKI was significantly lower in the balanced crystalloids group (12% vs. 22%, p = 0.01), with an adjusted odds ratio (OR) of 0.50 (95% CI 0.32-0.78, p = 0.002). The need for RRT was also reduced (8% vs. 15%, p = 0.03), with an adjusted OR of 0.55 (95% CI 0.30-0.95, p = 0.03). Although ICU mortality was lower in the balanced crystalloids group (18% vs. 24%), this difference did not reach statistical significance (p = 0.08). Subgroup analysis showed that in ARDS patients, fluid restriction combined with balanced crystalloids improved oxygenation (PaO2/FiO2 ratio of 220 vs. 180, p = 0.02) and reduced the duration of mechanical ventilation (six vs. nine days, p = 0.01). Similar benefits were observed in sepsis and heart failure patients. Balanced crystalloids are associated with a significant reduction in AKI incidence and RRT requirement compared to isotonic saline. Fluid restriction, particularly when combined with balanced crystalloids, improves clinical outcomes in patients with ARDS, sepsis, and heart failure. These findings support the preferential use of balanced crystalloids in critically ill patients and highlight the importance of individualized fluid management strategies in the ICU. Further research is needed to confirm these benefits and optimize fluid therapy protocols in diverse ICU populations.

Assessment of Initial Oxygenation Levels of Chronic Obstructive Pulmonary Disease (COPD) and Their Impact on Basis and Vital Tools: Retrospective Cohort Study From India.

Introduction Chronic obstructive pulmonary disease (COPD) is a significant contributor to global morbidity and mortality. Despite well-established management protocols, treatment remains suboptimal due to high costs and mortality rates. This study aims to compare the impact of initial oxygenation status, Dyspnea, Eosinopenia, Consolidation, Acidemia, and Atrial Fibrillation (DECAF), and National Early Warning Score 2 (NEWS2) scores on management outcomes in COPD patients. Methods In this retrospective study, we analyzed 100 consecutive patients admitted for COPD exacerbation. Patients were categorized into four groups based on admission oxygen saturation (SpO2): Group A (≤87%), Group B (88-92%), Group C (93-96%), and Group D (97-100%). Data collected included oxygen saturation, chest X-rays, laboratory findings, DECAF, and NEWS2 scores. Results The mean age of the cohort was 68.54 ± 10.95 years. Groups A and B (SpO2 ≤ 93-96%) had significantly higher rates of hypercapnia (50%), non-invasive ventilation use (63%), and prolonged hospital stays (15%) compared to Groups C and D (p < 0.05). A strong correlation was found between initial SpO2 and both DECAF (p = 0.04) and NEWS2 (p = 0.001) scores. DECAF correlated with arterial oxygen (pO2) and carbon dioxide (pCO2) levels, while NEWS2 was linked with pCO2, albumin, and white blood cell (WBC) counts (p < 0.05). Both DECAF and NEWS2 predicted longer hospital stays (p < 0.05). Conclusion An initial SpO2 ≤ 93-96% was an independent predictor of higher hypercapnia rates, extended hospitalization, and increased use of non-invasive ventilation. This emphasizes the importance of initial oxygenation status in the clinical assessment of COPD patients.

Revisiting the BE99 method for the study of outflowing gas in protostellar jets

An established method for measuring the hydrogen ionisation fraction in shock-excited gas is the BE99 method, which utilises six bright forbidden emission lines: S\,II N\,II 6583, and O\,I 6363. The main assumptions of this technique are that the gas is in a low-excitation state ($x_ e &lt; 0.3$) and that the equilibrium of the underlying ionisation network is reached. Our aim is to extend the BE99 method by including more emission lines in the blue and near-infrared part of the spectrum ($ and by considering higher hydrogen ionisation fractions ($x_ e &gt; 0.3$). In addition, we investigate how a non-equilibrium state of the gas and the presence of extinction influence the BE99 technique. We numerically solved a network of ionisation reactions in the time domain, which lead to the BE99 equilibrium. We applied the BE99 method on synthetic spectra also in the non-equilibrium state. We extented the BE99 technique to higher ionisation fractions by considering additional reactions, which involve higher ionisation states of oxygen, nitrogen, and sulphur. We tested our concepts on the low-excitation outflow of Par Lup 3-4 and the high-excitation 244-440 Proplyd in Orion. Many additional emission line ratios can in principle be exploited as extended curves (or stripes) in the ($x_ e T_ e $) diagram. If the BE99 equilibrium is reached and extinction is corrected for, all stripes overlap in one location in the ($x_ e T_ e $) diagram indicating the existing gas parameters. We find that the BE99 equilibrium is reached faster than the hydrogen recombination time. The application to the Par Lup 3-4 outflow shows that the classical BE99 lines together with the N\,I lines do not meet in one location in the ($x_ e T_ e $) diagram. This indicates that the gas parameters derived from the classical BE99 method are not fully consistent with other observed line ratios. A multi-line approach is necessary to determine the gas parameters. From our analysis we derive $n_e cm cm $, $T_e = 7\,600\ K K $, and $x_e 0.027-0.036$ for the Par Lup 3-4 outflow. For the 244-440 Proplyd we were able to use the line ratios of S\,II O\,I and OII 7330 in the BE99 diagram to estimate the ionisation fraction at knot E3 ($x_e = 0.58 The BE99 method can be extended by utilising more emission line ratios in the ($x_ e T_ e $) diagram and considering higher ionisation states. Exploiting new line ratios reveals more insights on the state of the gas. Our analysis indicates, however, that a multi-line approach is more robust in deriving gas parameters, especially for high-density gas.

Assessment of hypoxia and its dynamic evolution in glioblastoma via qBOLD MRI: a comparative study with metformin treatment

BackgroundTo investigate the accuracy of quantitative blood oxygen level-dependent (qBOLD) magnetic resonance imaging (MRI) in identifying hypoxia within glioblastoma and explore dynamic changes in oxygenation status of glioblastoma with and without metformin administration.MethodsThree healthy and seven C6-bearing rats underwent 7-T qBOLD MRI. Oxygen extraction fraction (OEF) and cerebral metabolism rate of O2 (CMRO2) were calculated from qBOLD data. Tumor tissues were stained using hypoxia-inducible factor-1α (HIF-1α) and pimonidazole. The correlation between the hypoxia markers and corresponding qBOLD-based parameters was analyzed. Six C6-bearing rats were divided into metformin-treated and control groups for a longitudinal study of qBOLD imaging changes, with scans conducted on the 12th, 15th, and 18th day post-tumor implantation.ResultsIn healthy rats, gray matter showed higher values than white matter in T2, T2*, cerebral blood volume (CBV), and cerebral blood flow (CBF), whereas OEF was lower. Glioblastoma tissues exhibited elevated T2, T2*, CBV, and CBF but decreased OEF and CMRO2 relative to normal-appearing white matter. No significant correlation was found between staining scores from HIF-1α and pimonidazole. T2* and T2 values were negatively correlated with pimonidazole scores in tumor regions. As the tumor progressed, OEF values increased with intra-tissue variations, whereas CMRO2 decreased. Metformin delayed the reduction of T2 and T2* values, with significant differences in OEF and CMRO2 values compared to controls on day 18.ConclusionT2* and T2 values were significantly associated with the hypoxia status in glioma. Metformin could potentially mitigate the progression of hypoxia in glioblastoma, which can be tracked by qBOLD parameters.Relevance statementThis study demonstrates the potential of qBOLD parameters in assessing glioma dynamic oxygen metabolism and the efficacy of metformin as an anti-hypoxic agent, providing insights into improving glioblastoma treatment strategies.Key PointsThe study investigated qBOLD imaging’s accuracy in identifying hypoxia status within glioblastoma.qBOLD effectively assesses hypoxia and its dynamic evolution in glioblastoma.qBOLD parameters assist in identifying a suitable patient demographic for metformin treatment.Graphical

Effect of extra corporeal reducing pre-load on pulmonary mechanical power in patients with acute respiratory distress syndrome

To explore the effects of veno-venous extra corporeal carbon dioxide removal (V-V ECCO2R) on local mechanical power and gas distribution in the lungs of patients with mild to moderate acute respiratory distress syndrome (ARDS) receiving non-invasive ventilation. Retrospective research methods were conducted. Sixty patients with mild to moderate ARDS complicated with renal insufficiency who were transferred to the respiratory intensive care unit (RICU) through the 96195 platform critical care transport green channel from January 2018 to January 2020 at the collaborative hospitals of Henan Provincial People's Hospital were enrolled. According to different treatment methods, they were divided into a conventional treatment group and an ECCO2R group, with 30 patients in each group. Both groups received standard treatments including primary disease treatment, airway management, and non-invasive ventilation. The conventional treatment group received bedside continuous renal replacement therapy (CRRT), and the ECCO2R group received V-V ECCO2R treatment. General information of patient such as gender, age, cause of disease, and acute physiology and chronic health evaluation II (APACHE II) were recorded; arterial blood gas analysis was performed before treatment and at 12 hours and 24 hours during treatment, recording arterial partial pressure of oxygen (PaO2), arterial partial pressure of carbon dioxide (PaCO2), and oxygenation index (PaO2/FiO2). Respiratory mechanics parameters [tidal volume, respiratory rate, maximal inspiratory pressure (MIP), and maximal expiratory pressure (MEP)] were recorded, and the rapid shallow breathing index (RSBI) was calculated; electrical impedance tomography (EIT) was used to measure regional of interest (ROI) values in different lung areas at 12 hours and 24 hours of treatment, and the pulmonary mechanical energy was calculated. The arterial blood gas analysis indicators, respiratory mechanics parameters, and pulmonary mechanical energy of patients in the conventional treatment group and ECCO2R group improved significantly after 24 hours of treatment compared to 12 hours of treatment (all P < 0.05). The levels of PaCO2, RSBI, total mechanical power, and non-dependent zone mechanical power in the ECCO2R group were significantly lower than those in the conventional treatment group at both 12 hours and 24 hours during the treatment [PaCO2 (mmHg, 1 mmHg ≈ 0.133 kPa): 44.03±2.96 vs. 49.96±2.50 at 12 hours, 41.65±3.21 vs. 48.53±2.33 at 24 hours; RSBI (times×min-1×L-1): 88.67±4.05 vs. 92.35±4.03 at 12 hours, 77.66±4.64 vs. 90.98±4.21 at 24 hours; total mechanical power (mJ): 10.40±1.15 vs. 12.93±1.68 at 12 hours, 11.13±1.18 vs. 14.05±1.69 at 24 hours; non-dependent zone mechanical power (mJ): 7.15±0.84 vs. 7.98±0.75 at 12 hours, 7.77±0.93 vs. 9.13±1.10 at 24 hours], and MEP and MIP in the ECCO2R group were significantly higher than those in the conventional treatment group at both 12 hours and 24 hours during the treatment [MEP (cmH2O, 1 cmH2O ≈ 0.098 kPa): 89.88±5.04 vs. 86.09±5.57 at 12 hours, 96.57±2.59 vs. 88.66±2.98 at 24 hours; MIP (cmH2O): 47.64±2.82 vs. 41.93±2.44 at 12 hours, 60.11±6.53 vs. 43.63±2.80 at 24 hours], the differences were statistically significant (all P < 0.05). V-V ECCO2R combined with non-invasive ventilation can effectively reduce the regional tidal volume, mechanical power, and respiratory rate in the non-gravitational dependent zones of patients with mild to moderate ARDS, and improve respiratory distress and oxygenation status.

Quantitative analysis of chest CT in coronavirus infected patients and its correlation with clinical features

To explore the quantitative analysis results of different patterns of chest computed tomography (CT) in patients with coronavirus infection and its relationship with viral load and pathophysiological status. A retrospective clinical cohort study was conducted. Patients with coronavirus infection admitted to Qingdao Municipal Hospital from June 9 to 15, 2023 (all patients underwent chest CT examination within 24 hours after diagnosis) were enrolled. The patients were divided into coronavirus infection non-pneumonia group and coronavirus infection associated pneumonia group according to CT findings. Relevant baseline data, such as demographic characteristics, chest CT characteristics, and laboratory indicators within 12 hours before and after CT examination were collected from each group. Spearman correlation test was used to quantitatively analyze the correlation between CT features and laboratory indicators. The receiver operator characteristic curve (ROC curve) was drawn to evaluate the predictive value of each laboratory index for pneumonia in patients infected with coronavirus. Multiple linear regression analysis was used to explore the relationship between different CT patterns such as ground-glass opacity (GGO) and consolidation and ventilatory oxygenation status. A total of 171 patients were enrolled, including 44 patients in the coronavirus infection non-pneumonia group and 127 patients in the coronavirus infection associated pneumonia group (the incidence of pneumonia was 74.3%). Compared with patients with coronavirus infection alone, patients with coronavirus infection associated pneumonia had significantly lower lymphocyte count (LYM), oxygenation index (PaO2/FiO2), total lung capacity, GGO volume and GGO ratio, and significantly higher C-reactive protein (CRP), neutrophil/lymphocyte ratio (NLR), D-dimer, fraction of inspired oxygen (FiO2) level, real volume variation and consolidation ratio, the differences were all statistically significant. There were no statistically significant differences in the nucleocapin protein (N) gene cycle threshold (Ct) value and open reading frame (ORF) gene Ct value between the two groups. ROC curve analysis showed that, after adjusting for age, gender, CRP level and other related factors, compared with N gene Ct value, ORF gene Ct value, N gene Ct value+LYM, ORF gene Ct value+LYM, the LYM had the most potential diagnosis power for coronavirus infection associated pneumonia. The area under the ROC curve (AUC) of LYM for predicting coronavirus infection was 0.703. When the cut-off value of LYM was 0.7×109/L, the sensitivity was 55.5%, and the specificity was 79.5%, respectively. Multiple linear regression analysis showed that, when adjusted for consolidation ratio, age, gender, Hb and D-dimer levels, the GGO ratio in patients with coronavirus infection associated pneumonia was correlated with PaO2/FiO2 (β = -2.18, P < 0.001). When adjusted for GGO ratio, age, sex, Hb and D-dimer levels, the proportion of consolidation in patients with coronavirus infection associated pneumonia was correlated with PaCO2 (β = 0.36, P = 0.004). When adjusted for GGO ratio, the proportion of consolidation in patients with coronavirus infection associated pneumonia was also associated with NLR (β = 0.79, P = 0.006). LYM could be a potential marker for predicting coronavirus associated pneumonia, and the correlation seems to be independent of viral load. In addition, in the analysis of imaging features, GGO is associated with hypoxia, while consolidation is associated with PaCO2 level and inflammation. The increased proportion of consolidation in the whole lung may be detrimental to lung ventilation.

Long-term dynamics of dissolved oxygen and isotopic composition in Lake Erie and Lake Ontario: Implications for eutrophication and ecosystem health

This study, focusing on Great Lakes Erie and Ontario, Canada, explores dissolved oxygen (DO) dynamics and its stable isotopic composition (δ18ODO) in the Great Lakes. Using historical dissolved oxygen data from 1965 to 2021, combined with synoptic isotopic data collected in the early 2000s, the research examined the spatiotemporal trends in DO and δ18O-DO to assess the effects of biotic and abiotic processes such as photosynthesis, respiration, and atmospheric gas exchange. The study revealed significant seasonal and depth-related variations in DO levels, with hypolimnetic hypoxia and metalimnetic oxygen minima (MOM) observed in both lakes. With its comparatively shallow depth and higher nutrient loads, Lake Erie exhibited more pronounced dissolved oxygen fluctuations, with DO levels reaching as low as 3.65 mg L−1 and δ18ODO values falling below +24.6 ‰. These findings indicated Lake Erie’s more dynamic metabolic environment, particularly during the thermally stratified season. In contrast, Lake Ontario showed more stable oxygen concentration levels, with occasional dissolved oxygen depletions down to 6.80 mg L−1 and δ18ODO values up to +32.1 ‰, suggesting more localised influences of external inputs and biological processes. This study provides a long-term perspective on dissolved oxygen status in these lakes and offers essential insights into their ecological health. This work contributes valuable data for managing and protecting the Great Lakes ecosystem.