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1.
Eur J Med Res ; 29(1): 304, 2024 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-38822441

RESUMO

PURPOSE: Respiratory dysfunction is one of the most frequent symptoms observed during sepsis reflecting hypoxemia and/or acidosis that may be assessed by the ROX index (ratio of oxygen saturation by pulse oximetry/fraction of inspired oxygen to respiratory rate). This study aimed to describe the relationship between the prehospital ROX index and 30-day mortality rate among septic shock patients cared for in the prehospital setting by a mobile intensive care unit (MICU). METHODS: From May 2016 to December 2021, 530 septic shock patients cared for by a prehospital MICU were retrospectively analysed. Initial ROX index value was calculated at the first contact with MICU. A Cox regression analysis after propensity score matching was performed to assess the relationship between 30-day mortality rate and a ROX index ≤ 10. RESULTS: Pulmonary, digestive and urinary sepsis were suspected among 43%, 25% and 17% patients, respectively. The 30-day overall mortality reached 31%. Cox regression analysis showed a significant association between 30-day mortality and a ROX index ≤ 10: adjusted hazard ratio of 1.54 [1.08-2.31], p < 0.05. CONCLUSIONS: During the prehospital stage of septic shock patients cared for by a MICU, ROX index is significantly associated with 30-day mortality. A prehospital ROX ≤ 10 value is associated with a 1.5-fold 30-day mortality rate increase. Prospective studies are needed to confirm the ability of prehospital ROX to predict sepsis outcome since the prehospital setting.


Assuntos
Choque Séptico , Humanos , Choque Séptico/mortalidade , Masculino , Feminino , Idoso , Pessoa de Meia-Idade , Estudos Retrospectivos , Oximetria/métodos , Saturação de Oxigênio , Idoso de 80 Anos ou mais , Taxa Respiratória , Serviços Médicos de Emergência/estatística & dados numéricos , Serviços Médicos de Emergência/métodos , Unidades de Terapia Intensiva/estatística & dados numéricos , Oxigênio
2.
Microbes Environ ; 39(2)2024.
Artigo em Inglês | MEDLINE | ID: mdl-38825479

RESUMO

The nitrite oxidizing bacterial genus Ca. Nitrotoga was only recently discovered to be widespread in freshwater systems; however, limited information is currently available on the environmental factors and seasonal effects that influence its distribution in lakes. In a one-year study in a dimictic lake, based on monthly sampling along a vertical profile, the droplet digital PCR quantification of Ca. Nitrotoga showed a strong spatio-temporal patchiness. A correlation ana-lysis with environmental parameters revealed that the abundance of Ca. Nitrotoga correlated with dissolved oxygen and ammonium, suggesting that the upper hypolimnion of the lake is the preferred habitat.


Assuntos
Lagos , Estações do Ano , Lagos/microbiologia , Lagos/química , Nitritos/metabolismo , Nitritos/análise , Compostos de Amônio/metabolismo , Compostos de Amônio/análise , Oxigênio/metabolismo , Oxigênio/análise , Ecossistema
3.
Water Sci Technol ; 89(10): 2661-2675, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38822606

RESUMO

The treatment of wastewater is highly challenging due to large fluctuations in flowrates, pollutants, and variable influent water compositions. A sequencing batch reactor (SBR) and modified SBR cycle-step-feed process (SSBR) configuration are studied in this work to effectively treat municipal wastewater while simultaneously removing nitrogen and phosphorus. To control the amount of dissolved oxygen in an SBR, three axiomatic control strategies (proportional integral (PI), fractional proportional integral (FPI), and fuzzy logic controllers) are presented. Relevant control algorithms have been designed using plant data with the models of SBR and SSBR based on ASM2d framework. On comparison, FPI showed a significant reduction in nutrient levels and added an improvement in effluent quality. The overall effluent quality is improved by 0.86% in FPI in comparison with PI controller. The SSBR, which was improved by precisely optimizing nutrient supply and aeration, establishes a delicate equilibrium. This refined method reduces oxygen requirements while reliably sustaining important biological functions. Focusing solely on the FPI controller's performance in terms of total air volume consumption, the step-feed SBR mechanism achieves an excellent 11.04% reduction in consumption.


Assuntos
Reatores Biológicos , Eliminação de Resíduos Líquidos , Eliminação de Resíduos Líquidos/métodos , Águas Residuárias , Fósforo/análise , Purificação da Água/métodos , Nitrogênio/análise , Poluentes Químicos da Água/análise , Oxigênio/análise
5.
Health Informatics J ; 30(2): 14604582241259341, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38847787

RESUMO

This study develops machine learning-based algorithms that facilitate accurate prediction of cerebral oxygen saturation using waveform data in the near-infrared range from a multi-modal oxygen saturation sensor. Data were obtained from 150,000 observations of a popular cerebral oximeter, Masimo O3™ regional oximetry (Co., United States) and a multi-modal cerebral oximeter, Votem (Inc., Korea). Among these observations, 112,500 (75%) and 37,500 (25%) were used for training and test sets, respectively. The dependent variable was the cerebral oxygen saturation value from the Masimo O3™ (0-100%). The independent variables were the time of measurement (0-300,000 ms) and the 16-bit decimal amplitudes values (infrared and red) from Votem (0-65,535). For the right part of the forehead, the root mean square error of the random forest (0.06) was much smaller than those of linear regression (1.22) and the artificial neural network with one, two or three hidden layers (2.58). The result was similar for the left part of forehead, that is, random forest (0.05) vs logistic regression (1.22) and the artificial neural network with one, two or three hidden layers (2.97). Machine learning aids in accurately predicting of cerebral oxygen saturation, employing the data from a multi-modal cerebral oximeter.


Assuntos
Aprendizado de Máquina , Oximetria , Saturação de Oxigênio , Humanos , Oximetria/métodos , Oximetria/instrumentação , Oximetria/estatística & dados numéricos , Saturação de Oxigênio/fisiologia , Algoritmos , Feminino , Masculino , Oxigênio/metabolismo , Oxigênio/análise
6.
BMC Plant Biol ; 24(1): 503, 2024 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-38840061

RESUMO

BACKGROUND: Oxygen concentration is a key characteristic of the fruit storage environment determining shelf life and fruit quality. The aim of the work was to identify cell wall components that are related to the response to low oxygen conditions in fruit and to determine the effects of such conditions on the ripening process. Tomato (Solanum lycopersicum) fruits at different stages of the ripening process were stored in an anoxic and hypoxic environment, at 0% and 5% oxygen concentrations, respectively. We used comprehensive and comparative methods: from microscopic immunolabelling and estimation of enzymatic activities to detailed molecular approaches. Changes in the composition of extensin, arabinogalactan proteins, rhamnogalacturonan-I, low methyl-esterified homogalacturonan, and high methyl-esterified homogalacturonan were analysed. RESULTS: In-depth molecular analyses showed that low oxygen stress affected the cell wall composition, i.e. changes in protein content, a significantly modified in situ distribution of low methyl-esterified homogalacturonan, appearance of callose deposits, disturbed native activities of ß-1,3-glucanase, endo-ß-1,4-glucanase, and guaiacol peroxidase (GPX), and disruptions in molecular parameters of single cell wall components. Taken together, the data obtained indicate that less significant changes were observed in fruit in the breaker stage than in the case of the red ripe stage. The first symptoms of changes were noted after 24 h, but only after 72 h, more crucial deviations were visible. The 5% oxygen concentration slows down the ripening process and 0% oxygen accelerates the changes taking place during ripening. CONCLUSIONS: The observed molecular reset occurring in tomato cell walls in hypoxic and anoxic conditions seems to be a result of regulatory and protective mechanisms modulating ripening processes.


Assuntos
Parede Celular , Frutas , Oxigênio , Pectinas , Proteínas de Plantas , Solanum lycopersicum , Parede Celular/metabolismo , Frutas/crescimento & desenvolvimento , Frutas/metabolismo , Solanum lycopersicum/crescimento & desenvolvimento , Solanum lycopersicum/metabolismo , Solanum lycopersicum/fisiologia , Oxigênio/metabolismo , Proteínas de Plantas/metabolismo , Pectinas/metabolismo , Mucoproteínas/metabolismo
7.
BMC Pulm Med ; 24(1): 268, 2024 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-38840165

RESUMO

BACKGROUND: The management of intractable secondary pneumothorax poses a considerable challenge as it is often not indicated for surgery owing to the presence of underlying disease and poor general condition. While endobronchial occlusion has been employed as a non-surgical treatment for intractable secondary pneumothorax, its effectiveness is limited by the difficulty of locating the bronchus leading to the fistula using conventional techniques. This report details a case treated with endobronchial occlusion where the combined use of transbronchoscopic oxygen insufflation and a digital chest drainage system enabled location of the bronchus responsible for a prolonged air leak, leading to the successful treatment of intractable secondary pneumothorax. CASE PRESENTATION: An 83-year-old male, previously diagnosed with chronic hypersensitivity pneumonitis and treated with long-term oxygen therapy and oral corticosteroid, was admitted due to a pneumothorax emergency. Owing to a prolonged air leak after thoracic drainage, the patient was deemed at risk of developing an intractable secondary pneumothorax. Due to his poor respiratory condition, endobronchial occlusion with silicone spigots was performed instead of surgery. The location of the bronchus leading to the fistula was unclear on CT imaging. When the bronchoscope was wedged into each subsegmental bronchus and low-flow oxygen was insufflated, a digital chest drainage system detected a significant increase of the air leak only in B5a and B5b, thus identifying the specific location of the bronchus leading to the fistula. With the occlusion of those bronchi using silicone spigots, the air leakage decreased from 200 mL/min to 20 mL/min, and the addition of an autologous blood patch enabled successful removal of the drainage tube. CONCLUSION: The combination of transbronchoscopic oxygen insufflation with a digital chest drainage system can enhance the therapeutic efficacy of endobronchial occlusion by addressing the problems encountered in conventional techniques, where the ability to identify the leaking bronchus is dependent on factors such as the amount of escaping air and the location of the fistula.


Assuntos
Broncoscopia , Drenagem , Insuflação , Pneumotórax , Humanos , Pneumotórax/terapia , Pneumotórax/cirurgia , Masculino , Idoso de 80 Anos ou mais , Drenagem/métodos , Broncoscopia/métodos , Insuflação/métodos , Oxigênio/administração & dosagem , Fístula Brônquica/cirurgia , Fístula Brônquica/terapia , Tomografia Computadorizada por Raios X , Tubos Torácicos , Brônquios
8.
Front Immunol ; 15: 1381059, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38855100

RESUMO

Background: Understanding COVID-19 outcomes remains a challenge. While numerous biomarkers have been proposed for severity at admission, limited exploration exists for markers during the infection course, especially for the requirement of oxygen therapy. This study investigates the potential of eosinophil count normalization as a predictor for oxygen weaning during the initial wave of the pandemic. Methods: A retrospective study was conducted between March and April 2020 (first wave) among adults admitted directly to a medicine ward. Biological abnormalities, including lymphocyte count, eosinophil count, and C-reactive protein (CRP), were gathered daily during the first week of admission according to oxygen level. In case of worsening, oxygen level was censored at 15 L/min. The primary aim was to assess whether eosinophil count normalization predicts a subsequent decrease in oxygen requirements. Results: Overall, 132 patients were admitted, with a mean age of 59.0 ± 16.3 years. Of the patients, 72% required oxygen, and 20.5% were admitted to the intensive care unit after a median delay of 48 hours. The median CRP at admission was 79 (26-130) mg/L, whereas the eosinophil count was 10 (0-60)/mm3. Eosinophil count normalization (≥100/mm3) by day 2 correlated significantly with decreased oxygen needs (<2 L) with hazard ratio (HR) = 3.7 [1.1-12.9] (p = 0.04). Likewise, CRP < 80 mg/L was associated with reduced oxygen requirements (p < 0.001). Predictors, including underlying chronic respiratory disease, exhibited a trend toward a negative association (p = 0.06). Conclusion: The study highlights the relationship between eosinophil count and CRP, with implications for predicting oxygen weaning during COVID-19. Further research is warranted to explore the relevance of these biomarkers in other respiratory infections.


Assuntos
COVID-19 , Eosinófilos , Oxigenoterapia , SARS-CoV-2 , Humanos , COVID-19/sangue , COVID-19/imunologia , COVID-19/terapia , COVID-19/epidemiologia , Masculino , Pessoa de Meia-Idade , Feminino , Estudos Retrospectivos , Eosinófilos/imunologia , Idoso , Contagem de Leucócitos , SARS-CoV-2/fisiologia , Adulto , Hospitalização , Biomarcadores/sangue , Proteína C-Reativa/análise , Proteína C-Reativa/metabolismo , Oxigênio/metabolismo , Oxigênio/sangue
9.
Cell Physiol Biochem ; 58(3): 226-249, 2024 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-38857359

RESUMO

BACKGROUND/AIMS: Important benefits of intermittent hypoxic training (IHT) have emerged as an effective tool for enhancing adaptive potential in different pathological states, among which acute hypoxia dominates. Therefore, the aim of our study was to evaluate the mechanisms related to the effects of the nitric oxide system (nitrites, nitrates, carbamide, and total polyamine content) on ADP-stimulated oxygen consumption and oxidative phosphorylation in heart and liver mitochondria and biomarkers of oxidative stress in the blood, heart, and liver of rats exposed to the IHT method and acute hypoxia and treated with the amino acid L-arginine (600 mg/kg, 30 min) or the NO synthase inhibitor L-NNA (35 mg/kg, 30 min) prior to each IHT session. METHODS: We analysed the modulation of the system of oxygen-dependent processes (mitochondrial respiration with the oxygraphic method, microsomal oxidation, and lipoperoxidation processes using biochemical methods) in tissues during IHT in the formation of short-term and long-term effects (30, 60, and 180 days after the last IHT session) with simultaneous administration of L-arginine. In particular, we investigated how mitochondrial functions are modulated during intermittent hypoxia with the use of oxidation substrates (succinate or α-ketoglutarate) in bioenergetic mechanisms of cellular stability and adaptation. RESULTS: The IHT method is associated with a significant increase in the production of endogenous nitric oxide measured by the levels of its stable metabolite, nitrite anion, in both plasma (almost 7-fold) and erythrocytes (more than 7-fold) of rats. The intensification of nitric oxide-dependent pathways of metabolic transformations in the energy supply processes in the heart and liver, accompanied by oscillatory mechanisms of adaptation in the interval mode, causes a probable decrease in the production of urea and polyamines in plasma and liver, but not in erythrocytes. The administration of L-arginine prior to the IHT sessions increased the level of the nitrite-reducing component of the nitric oxide cycle, which persisted for up to 180 days of the experiment. CONCLUSION: Thus, the efficacy of IHT and its nitrite-dependent component shown in this study is associated with the formation of long-term adaptive responses by preventing the intensification of lipoperoxidation processes in tissues due to pronounced changes in the main enzymes of antioxidant defence and stabilisation of erythrocyte membranes, which has a pronounced protective effect on the system of regulation of oxygen-dependent processes as a whole.


Assuntos
Arginina , Hipóxia , Consumo de Oxigênio , Ratos Wistar , Animais , Masculino , Hipóxia/metabolismo , Ratos , Arginina/farmacologia , Arginina/análogos & derivados , Arginina/metabolismo , Consumo de Oxigênio/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Óxido Nítrico/metabolismo , Oxigênio/metabolismo , Adaptação Fisiológica , Mitocôndrias Hepáticas/metabolismo , Mitocôndrias Hepáticas/efeitos dos fármacos , Fosforilação Oxidativa/efeitos dos fármacos , Fígado/metabolismo , Fígado/efeitos dos fármacos , Mitocôndrias Cardíacas/metabolismo , Mitocôndrias Cardíacas/efeitos dos fármacos , Peroxidação de Lipídeos/efeitos dos fármacos , Nitritos/metabolismo
10.
Zhonghua Jie He He Hu Xi Za Zhi ; 47(6): 529-534, 2024 Jun 12.
Artigo em Chinês | MEDLINE | ID: mdl-38858202

RESUMO

Objective: To evaluate the application value of portable pulse oximeter in adult obstructive sleep apnea (OSA). Methods: This study prospectively enrolled adult patients who underwent polysomnography (PSG) due to snoring at the Respiratory and Sleep Medicine Department of Peking University People's Hospital from July 2022 to July 2023. During PSG monitoring, CS-WOxi was continuously used to monitor blood oxygen levels. The consistency between 3% oxygen desaturation index (ODI3) measured by portable pulse oximeter and ODI3 of polysomnography was evaluated using difference test, Pearson's correlation coefficient, and Bland-altman method. Receiver operating characteristic curve was used to determine the optimal threshold for diagnosing OSA. Results: A total of 184 subjects were included, including 121 males (65.8%) and 63 females (34.2%). The mean age was 46.0 (34.3, 59.0) years, body mass index was 26.0 (23.3, 29.6) kg/m², and the apnea-hypopnea index was 18.2 (5.8, 40.8) events/h. There was a significant difference between CS-ODI3 and PSG-ODI3 [17.1(6.2, 42.7) vs. 14.0(2.9, 32.6), P<0.001], and the Pearson correlation coefficient was 0.93 (P<0.001). There was a good correlation between CS-ODI3 and PSG-AHI (r=0.92, P<0.001). Bland-Altman consistency test showed that the average difference between the two was 0.7 events/h, and the 95% consistency limit was (-17.9, 19.3 events/h). When the CS-ODI3≥5 events/h was used to identify OSA, the sensitivity was 94.4%, the specificity was 80.0%, and the accuracy was 91.3%. When PSG-AHI≥5 events/h was used as the diagnostic criteria, the area under the receiver operating characteristic curve was 0.933. Conclusion: Portable pulse oximeter can monitor pulse oxygen saturation accurately and has good sensitivity and specificity for OSA high-risk patients, and is a reliable tool for OSA screening.


Assuntos
Oximetria , Polissonografia , Apneia Obstrutiva do Sono , Humanos , Apneia Obstrutiva do Sono/diagnóstico , Apneia Obstrutiva do Sono/sangue , Oximetria/métodos , Oximetria/instrumentação , Feminino , Masculino , Pessoa de Meia-Idade , Adulto , Polissonografia/métodos , Estudos Prospectivos , Curva ROC , Sensibilidade e Especificidade , Índice de Massa Corporal , Oxigênio/sangue
11.
Methods Mol Biol ; 2792: 163-173, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38861086

RESUMO

Photosynthesis and metabolism in plants involve oxygen as both a product and substrate. Oxygen is taken up during photorespiration and respiration and produced through water splitting during photosynthesis. To distinguish between processes that produce or consume O2 in leaves, isotope mass separation and detection by mass spectrometry allows measurement of evolution and uptake of O2 as well as CO2 uptake. This chapter describes how to calculate the rate of Rubisco oxygenation and carboxylation from in vivo gas exchange of stable isotopes of 16O2 and 18O2 with a closed cuvette system for leaf discs and membrane inlet mass spectrometry.


Assuntos
Espectrometria de Massas , Oxigênio , Fotossíntese , Espectrometria de Massas/métodos , Oxigênio/metabolismo , Isótopos de Oxigênio/metabolismo , Folhas de Planta/metabolismo , Dióxido de Carbono/metabolismo , Ribulose-Bifosfato Carboxilase/metabolismo , Respiração Celular
12.
Methods Mol Biol ; 2792: 175-184, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38861087

RESUMO

Leaf-level gas exchange is widely used to investigate the largest carbon fluxes in illuminated leaves, offering a nondestructive way to investigate the impact of photorespiration on plant carbon balance. Modern commercial gas exchange systems allow high temporal resolution measurements under changing environments, aiding the development of nonsteady-state approaches for measuring dynamic photosynthetic responses. Here, we describe a nonsteady-state technique for acquiring the dynamic response of net CO2 assimilation to changes in photorespiratory fluxes manipulated by O2 mole fractions. This technique allows for the screening of plant genotypes with variations in their efficiencies of photorespiration under nonsteady-state conditions.


Assuntos
Dióxido de Carbono , Oxigênio , Fotossíntese , Folhas de Planta , Oxigênio/metabolismo , Dióxido de Carbono/metabolismo , Folhas de Planta/metabolismo , Respiração Celular
13.
Methods Mol Biol ; 2792: 187-194, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38861088

RESUMO

Photorespiration is an essential process of phototropic organisms caused by the limited ability of rubisco to distinguish between CO2 and O2. To understand the metabolic flux through the photorespiratory pathway, we combined a mass spectrometry-based approach with a shift experiment from elevated CO2 (3000 ppm) to ambient CO2 (390 ppm). Here, we describe a protocol for quantifying photorespiratory intermediates, starting from plant cultivation through extraction and evaluation.


Assuntos
Dióxido de Carbono , Espectrometria de Massas , Dióxido de Carbono/metabolismo , Dióxido de Carbono/análise , Espectrometria de Massas/métodos , Fotossíntese , Ribulose-Bifosfato Carboxilase/metabolismo , Oxigênio/metabolismo , Oxigênio/análise , Folhas de Planta/metabolismo
14.
Methods Mol Biol ; 2792: 143-161, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38861085

RESUMO

Measures of respiration in the light and Ci* are crucial to the modeling of photorespiration and photosynthesis. This chapter provides background on the equations used to model C3 photosynthesis and the history of the incorporation of the effects of rubisco oxygenation into these models. It then describes three methods used to determine two key parameters necessary to incorporate photorespiratory effects into C3 photosynthesis models: respiration in the light (RL) and Ci*. These methods include the Laisk, Yin, and isotopic methods. For the Laisk method, we also introduce a new rapid measurement technique.


Assuntos
Dióxido de Carbono , Fotossíntese , Ribulose-Bifosfato Carboxilase , Dióxido de Carbono/metabolismo , Ribulose-Bifosfato Carboxilase/metabolismo , Modelos Biológicos , Luz , Oxigênio/metabolismo , Respiração Celular
15.
Methods Mol Biol ; 2792: 195-208, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38861089

RESUMO

We describe here a method to study and manipulate photorespiration in intact illuminated leaves. When the CO2/O2 mole fraction ratio changes, instant sampling is critical, to quench leaf metabolism and thus trace rapid metabolic modification due to gaseous conditions. To do so, we combine 13CO2 labeling and gas exchange, using a large custom leaf chamber to facilitate fast sampling by direct liquid nitrogen spraying. Moreover, the use of a high chamber surface area (about 130 cm2) allows one to sample a large amount of leaf material to carry out 13C-nuclear magnetic resonance (NMR) analysis and complementary analyses, such as isotopic analyses by high-resolution mass spectrometry (by both GC and LC-MS). 13C-NMR gives access to absolute 13C amounts at the specific carbon atom position in the labeled molecules and thereby provides an estimate of 13C-flux of photorespiratory intermediates. Since NMR analysis is not very sensitive and can miss minor metabolites, GC or LC-MS analyses are useful to monitor metabolites at low concentrations. Furthermore, 13C-NMR and high-resolution LC-MS allow to estimate isotopologue distribution in response to 13CO2 labeling while modifying photorespiration activity.


Assuntos
Dióxido de Carbono , Isótopos de Carbono , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Folhas de Planta , Folhas de Planta/metabolismo , Folhas de Planta/química , Espectrometria de Massas/métodos , Espectroscopia de Ressonância Magnética/métodos , Dióxido de Carbono/metabolismo , Dióxido de Carbono/análise , Isótopos de Carbono/química , Fotossíntese , Oxigênio/metabolismo , Oxigênio/análise
16.
Wounds ; 36(5): 154-159, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38861210

RESUMO

BACKGROUND: Sufficient oxygen is critical for multiple processes in wound healing. Nonhealing wounds have low tissue oxygen levels due to damaged microvasculature and comorbidities limiting tissue perfusion. Hypoxia may be reversed using continuous topical oxygen therapy (cTOT). Objective measures to identify and track hypoxic wounds and their response to adjunctive oxygen are key. OBJECTIVE: To understand the effect of cTOT on recalcitrant wounds by tracking wound area and changes in tissue oxygenation using a near-infrared spectroscopy (NIRS) device. MATERIALS AND METHODS: Five patients with nonhealing wounds received treatment with cTOT over 5 weeks. Routine wound measures and tissue oxygenation were recorded over that period. RESULTS: Reductions in wound area and improvements in tissue oxygenation were seen in all 5 patients, with 3 patients healing within 5 weeks despite the previous long duration of their wounds. Trends in tissue oxygenation and relative wound surface area over the treatment period demonstrated a reduction in wound area as tissue oxygenation improved. CONCLUSION: This case series reinforces previous studies that cTOT is an effective, noninvasive treatment as a key adjunct to standard care in nonhealing wounds. Moreover, point-of-care tools such as the NIRS imaging device provided objective information concerning tissue oxygenation improvements, thus giving useful insights to the clinician.


Assuntos
Oxigênio , Espectroscopia de Luz Próxima ao Infravermelho , Cicatrização , Humanos , Cicatrização/fisiologia , Espectroscopia de Luz Próxima ao Infravermelho/métodos , Projetos Piloto , Masculino , Feminino , Idoso , Oxigênio/metabolismo , Pessoa de Meia-Idade , Resultado do Tratamento , Administração Tópica , Idoso de 80 Anos ou mais , Adulto
17.
J Opt Soc Am A Opt Image Sci Vis ; 41(6): 1128-1139, 2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38856427

RESUMO

Photoacoustic (PA) spectroscopy is considered to be one of the most effective ways to measure the levels of hematocrit (H) and oxygenation saturation (S O 2) of blood, which are essential for diagnosing blood-related illnesses. This simulation study aims to investigate the impact of individual optical parameters, i.e., optical absorption coefficient (µ a), scattering coefficient (µ s), and anisotropy factor (g), on the accuracy of this technique in estimating the blood properties. We first performed the Monte Carlo simulations, using realistic optical parameters, to obtain the fluence maps for various samples. The wavelengths of the incident light were chosen to be 532, 700, 1000, and 1064 nm. Thereafter, the k-Wave simulations were executed, incorporating those fluence maps to generate the PA signals. The blood properties were obtained using the PA signals. We introduced variations in µ a, µ s, and g ranging from -10% to +10%, -10% to +10%, and -5% to +1%, respectively, at 700 and 1000 nm wavelengths. One parameter, at both wavelengths, was changed at a time, keeping others fixed. Subsequently, we examined how accurately the blood parameters could be determined at physiological hematocrit levels. A 10% variation in µ a induces a 10% change in H estimation but no change in S O 2 determination. Almost no change has been seen for µ s variation. However, a 5% (-5% to 0%) variation in the g factor resulted in approximately 160% and 115% changes in the PA signal amplitudes at 700 and 1000 nm, respectively, leading to ≈125% error in hematocrit estimation and ≈14% deviation in S O 2 assessment when nominal S O 2=70%. It is clear from this study that the scattering anisotropy factor is a very sensitive parameter and a small change in its value can result in large errors in the PA estimation of blood properties. In the future, in vitro experiments with pathological blood (inducing variation in the g parameter) will be performed, and accordingly, the accuracy of the PA technique in quantifying blood H and S O 2 will be evaluated.


Assuntos
Método de Monte Carlo , Saturação de Oxigênio , Técnicas Fotoacústicas , Hematócrito , Técnicas Fotoacústicas/métodos , Humanos , Oxigênio/metabolismo , Oxigênio/sangue , Fenômenos Ópticos
18.
J Am Chem Soc ; 146(23): 15986-15999, 2024 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-38833517

RESUMO

Understanding how water ligands regulate the conformational changes and functionality of the oxygen-evolving complex (OEC) in photosystem II (PSII) throughout the catalytic cycle of oxygen evolution remains a highly intriguing and unresolved challenge. In this study, we investigate the effect of water insertion (WI) on the redox state of the OEC by using the molecular dynamics (MD) and quantum mechanics/molecular mechanics (QM/MM) hybrid methods. We find that water binding significantly reduces the free energy change for proton-coupled electron transfer (PCET) from Mn to YZ•, underscoring the important regulatory role of water binding, which is essential for enabling the OEC redox-leveling mechanism along the catalytic cycle. We propose a water binding mechanism in which WI is thermodynamically favored by the closed-cubane form of the OEC, with water delivery mediated by Ca2+ ligand exchange. Isomerization from the closed- to open-cubane conformation at three post-WI states highlights the importance of the location of the MnIII center in the OEC and the orientation of its Jahn-Teller axis to conformational changes of the OEC, which might be critical for the formation of the O-O bond. These findings reveal a complex interplay between conformational changes in the OEC and the ligand environment during the activation of the OEC by YZ•. Analogous regulatory effects due to water ligand binding are expected to be important for a wide range of catalysts activated by redox state transitions in aqueous environments.


Assuntos
Oxirredução , Oxigênio , Complexo de Proteína do Fotossistema II , Água , Complexo de Proteína do Fotossistema II/química , Complexo de Proteína do Fotossistema II/metabolismo , Água/química , Ligantes , Oxigênio/química , Oxigênio/metabolismo , Simulação de Dinâmica Molecular , Termodinâmica , Teoria Quântica
19.
Zhongguo Yi Liao Qi Xie Za Zhi ; 48(3): 330-334, 2024 May 30.
Artigo em Chinês | MEDLINE | ID: mdl-38863103

RESUMO

Pulse rate and blood oxygen levels are crucial physiological parameters that reflect physiological and pathological information within the human body. The system designs a wireless pulse wave monitoring system utilizing a flexible reflective probe and the AFE4490, which is capable of monitoring pulse wave and blood oxygen levels on the human forehead. The system is predominantly based on a reflective flexible probe, the AFE4490, a power supply module, a control microcontroller unit (MCU), and a Wi-Fi module. Post-processing by a slave computer, the collected pulse wave data is wirelessly transmitted to a smartphone. The real-time pulse waveform, pulse rate, and blood oxygen levels are displayed on an application. Following relevant tests and verifications, the system can accurately detect pulse wave signals, meet the requirements for wearable technology, and possesses significant market application potential.


Assuntos
Tecnologia sem Fio , Monitorização Fisiológica/instrumentação , Humanos , Análise de Onda de Pulso/instrumentação , Smartphone , Frequência Cardíaca , Oxigênio , Processamento de Sinais Assistido por Computador , Dispositivos Eletrônicos Vestíveis
20.
PLoS One ; 19(6): e0300602, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38829894

RESUMO

OBJECTIVES: Describing mitochondrial oxygenation (mitoPO2) and its within- and between-subject variability over time after 5-aminolevulinic acid (ALA) plaster application in healthy volunteers. DESIGN: Prospective cohort study. SETTING: Measurements were performed in Leiden University Medical Center, the Netherlands. PARTICIPANTS: Healthy volunteers enrolled from July to September 2020. INTERVENTIONS: Two ALA plasters were placed parasternal left and right, with a 3-hour time interval, to examine the influence of the calendar time on the value of mitoPO2. We measured mitoPO2 at 4, 5, 7, 10, 28, and 31 hours after ALA plaster 1 application, and at 4, 5, 7, 25, and 28 hours after ALA plaster 2 application. PRIMARY AND SECONDARY OUTCOME MEASURES: At each time point, five mitoPO2 measurements were performed. Within-subject variability was defined as the standard deviation (SD) of the mean of five measurements per timepoint of a study participant. The between-subject variability was the SD of the mean mitoPO2 value of the study population per timepoint. RESULTS: In 16 completed inclusions, median mitoPO2 values and within-subject variability were relatively similar over time at all time points for both plasters. An increase in overall between-subject variability was seen after 25 hours ALA plaster time (19.6 mm Hg vs 23.9 mm Hg after respectively 10 and 25 hours ALA plaster time). CONCLUSIONS: The mitoPO2 values and within-subject variability remained relatively stable over time in healthy volunteers. An increase in between-subject variability was seen after 25 hours ALA plaster time warranting replacement of the ALA plaster one day after its application. TRIAL REGISTRATION: ClinicalTrials.gov with trial number NCT04626661.


Assuntos
Voluntários Saudáveis , Oxigênio , Humanos , Masculino , Feminino , Adulto , Oxigênio/metabolismo , Estudos Prospectivos , Mitocôndrias/metabolismo , Pessoa de Meia-Idade , Ácido Aminolevulínico/administração & dosagem , Consumo de Oxigênio , Adulto Jovem , Países Baixos
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