Oxygenation

Contractions of athlete’s foot and its muscle oxygenation

Published on: 5th December, 2018

Sustained isometric contractions of skeletal muscles produce intramuscular pressures that leads to blood flow restriction. In result an active muscle feels deficit of oxygen what bring to muscle fatigue. In another side during exercise we have physiological contradiction between raising of oxygen demand by working muscle and restriction of blood flow due to vessel pressing. To clarify this issue many research has been performed based mainly on measurement of blood flow in muscle tissue. The purpose of this study was to assess real-time changes in muscle oxygenation during a sustained isometric contractions of dorsiflexor muscle of low (30%), moderate (60%) and submaximal (90%) intensity. Experiments were conducted using the subject’s dominant (right) leg. Volunteers was recruited from eight male students of USIPC (age: 19±2 years, weight: 75±6 kg). Tissue oxygenation index (StO2) were recorded from the tibialis anterior using NIRS device (NONIN). Saturation was higher at 30% compared with both 60% and 90% MVC at all time points after start exercise and higher at 60% than 90%. Oxygen consumption (VO2) permanently increased from slow (30%) to moderate (60%) and submaximal contractions. After cessation of the each contraction there was a large and immediate hyperemic response. Rate of StO2 increasing after effort cessation what reflects the resaturation of hemoglobin which depend on integrity and functionality of vascular system and reflects blood vessel vasodilation. StO2 restoration rate permanently increased from slow (30%) to moderate (60%) and submaximal contractions too. At last on final stage of experiment arterial occlusion test has been performed to determine the minimal oxygen saturation value in the dorsiflexors. Oxygen saturation reached a 24±1.77% what is significantly higher than StO2 after 60 and 90%MVC. So, we can conclude that oxygen saturation at 60% and 90% MVC are similar and sharply decreased after start of exercise. It means that after 60% MVC take place occlusion of blood vessels due to intramuscular pressure. Oxygen consumption of active muscle increased depend on intensity of exertion according to increasing of oxygen demand. StO2 resaturation rate (Re) permanently increased from slow (30%) to moderate (60%) and to submaximal contractions. Re increasing after effort cessation reflects the resaturation of hemoglobin which depend on integrity and functionality of vascular system and reflects blood vessel vasodilation.
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Single Trans apical access for double aortic and mitral valves-in-valves procedures with high risk of thrombus embolism

Published on: 16th July, 2019

OCLC Number/Unique Identifier: 8192819595

Background: Persistent left atrial thrombus remains a contra indication to transeptal valves in valves procedure. We aimed to perform a double valves in valves replacement through transapical access with cerebral angiography control during the procedure just after implantation. Our case shows the feasibility of this strategy and the management of right ventricle laceration successfully treated after extra corporeal membrane oxygenation implantation and local hemostasis. We reported a feasibility case report of successful double valves in valves implantation through transapical access with 6 months of clinical and computed tomography follow up.
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Avoiding confusion in high flow oxygen therapy concepts

Published on: 31st May, 2017

OCLC Number/Unique Identifier: 7317646410

Oxygen therapy is the main supportive treatment in hypoxemic respiratory failure and has traditionally been delivered using low and high flow devices. However, the maximal flow rates that these devices can deliver are limited because of the insufficient heat and humidity provided to the gas administered. Low flow devices such as the nasal cannula, conventional face mask and reservoir bag deliver a flow rate of up to 15 L/min by administering more variable oxygen fractions (FiO2), depending on the patient’s respiratory pattern, peak inspiratory flow and characteristics of the devices. Conventional high flow devices, such as venturi type masks, utilize a constant flow of oxygen through precisely sized ports, entraining the ambient air, using the Bernoulli principle, providing a more constant inspired oxygen fraction. However, they are less tolerated than nasal cannulas because they are less comfortable and the insufficient humidification and heating of the gas delivered [1]. In the last two decades, new devices have been developed to administer high humidified and heated flow through a nasal cannula (HFNC) that also allows the delivery of oxygen with a known FiO2 up to 100%. In the literature, this technique has also been called mini CPAP (continuous positive airway pressure), transnasal insufflation, high nasal flow ventilation, high flow oxygen therapy, and high flow nasal cannula oxygen therapy [2]. It is considered that high flow nasal cannula has certain benefits compared to those of oxygen therapy previously detailed. HFNC manages a flow of more than 30 L/min, which is able to surpass the peak inspiratory flow of the patient, being able to reach values ​​between 60-80 L/min depending on the flow used. The gas source, which may be delivered by an air/oxygen blender, fans, or a flow generating turbine, is connected by an active humidifier to a nasal cannula and the FiO2 can be adjusted independently of the flow. From a clinical point of view, there is some confusion between venturi and high flow nasal cannula devices. In the literature, both have been considered as high flow oxygen therapy devices. In our opinion this is not appropriate because the high nasal cannula flow is much more than a simple system for administering oxygen therapy [3]. Venturi-type masks provide the patient with a gas mixture with a controlled FiO2, but do not exert additional benefits on the ventilator mechanics of the patient. Nevertheless, HFNC allows the delivery of a high flow, which can also add oxygen therapy, providing a series of physiological effects that imply an active treatment to respiratory failure. Effects related to HFNC include the following: 1. Delivery of higher and more stable FiO2 values, ​​because the flow delivered is greater than the patient’s inspiratory demand. 2. The anatomical dead space decreases by washing the nasopharynx, consequently increases alveolar ventilation. This improves the thoracoabdominal synchrony. 3. Respiratory work decreases because it acts as a mechanical stent in the airway and markedly attenuates inspiratory resistance. 4. The gas administered is warmed and humidified, improving mucociliar clearance, reducing the risk of atelectasis, improving ventilation perfusion and oxygenation ratio. 5. There is a CPAP-like effect. The dynamic positive espiratory airway pressure generated by HFNC reaches a value between 6-8cmH2o depending on the flow and the size of the cannula. This positive pressure distends the lungs and ensures their recruitment. 6. Pulmonary end-expiratory volume is higher with HFCN than with conventional high-flow oxygen therapy. 7. In addition, the technique is considered easy and simple for the medical staff and nurses, and can be used in different areas (emergency, hospitalization, critical care unit, weaning centers) and even at home [4]. Currently available evidence has demonstrated that HFNC therapy is an alternative for the treatment of acute hypoxemic respiratory failure, hypercapnic respiratory failure, acute heart failure, as rescue therapy preventive therapy in post-extubation respiratory failure and in specific conditions such as bronchoscopy [5]. We believe that high-flow nasal cannula treatment should not be confused with high flow oxygen therapy of venturi masks. According to detailed mechanisms of action, HFNC is not limited to being only an oxygen therapy system but also behaves as a true treatment that can be used in different clinical scenarios, generating physiological benefits that result in the reduction of respiratory work. In addition, in venturi type masks, the air is not humidified and complications such as dryness and nasal pain are common, generating a poor tolerance to oxygen therapy. The benefits of proper humidification and heating of the gas delivered with HFNC therapy allow better comfort and tolerance of the patient with easy adherence to the treatment. All this contributes to making HFNC be considered a technique of choice in patients with hypoxemic respiratory failure. The growth in its use associated with easy acceptance for patients and the expansion in its application show us that HFNC is a promising therapy.
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Chronic fatigue syndrome and epigenetics: The case for hyperbaric oxygen therapy in biomarker identification

Published on: 26th February, 2021

OCLC Number/Unique Identifier: 9038783706

Chronic fatigue syndrome (CFS) is a poorly-understood respiratory condition that affects millions of individuals. Hyperbaric oxygen therapy (HBOT) is a treatment option being considered to address CFS as it is suggested to combat fatigue and increase oxygenation. HBOT provides two opportunities in advancing research of CFS: it may provide data on symptom amelioration and be utilized in the search for a biomarker. By either identifying biomarkers before using HBOT to compare epigenomes of patients before and after treatment or using HBOT to find epigenetic discrepancies between patients with and without treatment, matching epigenetic regulation with symptom amelioration may significantly advance the understanding of the etiology and treatment mechanism for CFS. EPAS1/HIF-2α is a leading candidate for an epigenetic biomarker as it responds differentially to hypoxic and normoxic conditions, which degrades more slowly in hypoxic conditions. Epigenetic regulation of EPAS1/HIF-2α in such differential conditions may be explored in HBOT experiments. In addition to HBOT as a promising treatment option for CFS symptoms, it may aid the identification of biomarkers in CFS. Further research into both outcomes is strongly encouraged.
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Protective functions of AEURA in Cell Based Model of Stroke and Alzheimer disease

Published on: 6th June, 2017

OCLC Number/Unique Identifier: 7317651488

Stroke and neurodegenerative diseases including Alzheimer’s disease (AD) are responsible for a major proportion of mortalities in the elderly. We have previously investigated novel mechanism-based therapies of AEURA in cell culture models against viral infection and in glutamate excitotoxity. In our new studies, we propose that the homeopathic formula AEURA could serve as a potential therapeutic agent for stroke & for AD. In examining AEURA treatment of PC12 cells exposed to glutamate excitotoxicity, hypoxia /re-oxygenation injury and A-Beta toxicity. We demonstrated an increased survival rate in AEURA treated cells by comparison to control cells. In examining the therapeutic potential of AEURA in PC12 cells this homeopathic agent was found to be neuroprotective against either glutamate induced toxicity, hypoxia /re-oxygenation stress or cell stress resulting from viral infection (with either HSV-1 or rhinovirus). Our ongoing studies involve examining the neuroprotective potential AEURA in vivo using rodent models of stroke & AD.
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An update in the utilization of N-acetyl cysteine & vitamin c for tackling the oxidative stress in acute kidney injury secondary to robust sepsis - A systematic review

Published on: 1st February, 2022

OCLC Number/Unique Identifier: 9414669659

The commonest etiology of acute kidney injury (AKI) is Sepsis that results in an escalation of morbidity and mortality in the hospital intensive care units. Existentially, the therapy of septic AKI rather than being definitive or curative is just supportive, without tackling the pathophysiology. Usually, Sepsis gets correlated with systemic inflammation, along with the escalated generation of Reactive oxygen species (ROS), in particular superoxide. Simultaneously liberation of nitric oxide (NO) subsequently reacts with the superoxide, thus, resulting in the generation of reactive nitrogen species (RNS), that is mostly peroxynitrite. This sepsis stimulated generation of ROS in addition to RNS might cause a reduction in the bioavailability of NO that modulates microcirculation aberrations, localized tissue hypoxia as well as mitochondrial impairment, thus starting a vicious cycle of cellular damage which results in AKI. Here we conducted a systematic review utilizing search engine PubMed, Google scholar; Web of science; Embase; Cochrane review library utilizing the MeSH terms like septic AKI; ROS; inducible nitric oxide synthase (iNOS); nicotinamide adenine nucleotide phosphate(NADPH)oxidase complex; Oxidative stress; Renal medullary hypoxia; Hypoxia inducible factor1; hypoxia responsive enhancer A; mitochondrial impairment; Intrarenal oxygenation; urinary oxygenation; erythropoietin gene; RRT; NAC; Vitamin C from 1950 to 2021 till date. We found a total of 6500 articles out of which we selected 110 articles for this review. No meta-analysis was done. Thus here we detail the different sources of ROS, at the tie of sepsis, besides their pathophysiological crosstalk with the immune system, microcirculation as well as mitochondria that can result in the generation of AKI. Furthermore, we detail the therapeutic utility of N-acetylcysteine (NAC), besides the reasons for its success in ovine as well as porcine models of AKI. Moreover, we discuss preclinical along with clinical for evaluation of Vitamin C’s antioxidant effects as well as pleiotropic effects as a stress hormone that might aid in abrogation of septic AKI.
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