scholarly journals In vivo oxygen measurement in cerebrospinal fluid of pigs to determine physiologic and pathophysiologic oxygen values during CNS infections

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Nicole de Buhr ◽  
Alexander Martens ◽  
Marita Meurer ◽  
Marta C. Bonilla ◽  
Franz Söbbeler ◽  
...  
Keyword(s):  
Partial Pressure ◽  
Ph Value ◽  
Cell Number ◽  
Bacterial Number ◽  
Oxygen Level ◽  
Partial Pressure Of Oxygen ◽  
Oxygen Levels ◽  
In Vivo Measurement ◽  
Cns Infections

AbstractDuring infection and inflammation, a reduced oxygen level clearly affects cellular functions. Oxygen levels during CNS infections are unknown. Here we established and evaluated an in vivo measurement system to characterize the oxygen level in parallel with bacterial numbers (CFU/mL), the cell number and pH level inside the CSF of healthy compared to Streptococcus suis-infected pigs. The animals were anesthetized over a seven-hour period with isoflurane in air/oxygen at physiologic arterial partial pressure of oxygen. Oxygen levels in CSF of anesthetized pigs were compared to euthanized pigs. The detected partial pressure of oxygen in the CSF remained constant in a range of 47–63 mmHg, independent of the infection status (bacterial or cell number). In contrast, the pH value showed a slight drop during infection, which correlated with cell and bacterial number in CSF. We present physiologic oxygen and pH values in CSF during the onset of bacterial meningitis.

In vivo Monitoring of Oxygen Levels in Human Brain Tumor Between Fractionated Radiotherapy Using Oxygen-enhanced MR Imaging

2020 ◽  
Vol 16 (4) ◽  
pp. 427-432
Author(s):  
Junchao Qian ◽  
Xiang Yu ◽  
Bingbing Li ◽  
Zhenle Fei ◽  
Xiang Huang ◽  
...  
Keyword(s):  
Mr Imaging ◽  
Tumor Cells ◽  
Normal Tissue ◽  
Oxygen Level ◽  
Tissue Oxygen ◽  
Human Brain Tumor ◽  
Fractionated Radiotherapy ◽  
Oxygen Levels ◽  
Oxygen Breathing

Background:: It was known that the response of tumor cells to radiation is closely related to tissue oxygen level and fractionated radiotherapy allows reoxygenation of hypoxic tumor cells. Non-invasive mapping of tissue oxygen level may hold great importance in clinic. Objective: The aim of this study is to evaluate the role of oxygen-enhanced MR imaging in the detection of tissue oxygen levels between fractionated radiotherapy. Methods: A cohort of 10 patients with brain metastasis was recruited. Quantitative oxygen enhanced MR imaging was performed prior to, 30 minutes and 22 hours after first fractionated radiotherapy. Results: The ΔR1 (the difference of longitudinal relaxivity between 100% oxygen breathing and air breathing) increased in the ipsilateral tumor site and normal tissue by 242% and 152%, respectively, 30 minutes after first fractionated radiation compared to pre-radiation levels. Significant recovery of ΔR1 in the contralateral normal tissue (p < 0.05) was observed 22 hours compared to 30 minutes after radiation levels. Conclusion: R1-based oxygen-enhanced MR imaging may provide a sensitive endogenous marker for oxygen changes in the brain tissue between fractionated radiotherapy.

scholarly journals FT-4202, an oral PKR activator, has potent antisickling effects and improves RBC survival and Hb levels in SCA mice

2021 ◽  
Vol 5 (9) ◽  
pp. 2385-2390
Author(s):  
Archana Shrestha ◽  
Mengna Chi ◽  
Kimberly Wagner ◽  
Astha Malik ◽  
Jennifer Korpik ◽  
...  
Keyword(s):  
Shear Stress ◽  
Blood Cell ◽  
Partial Pressure ◽  
Sickle Cell Anemia ◽  
Biological Effects ◽  
Membrane Damage ◽  
Partial Pressure Of Oxygen ◽  
Sickle Hemoglobin ◽  
Investigational Agent

Abstract Sickle cell anemia (SCA) results from an abnormal sickle hemoglobin (HbS). HbS polymerizes upon deoxygenation, resulting in red blood cell (RBC) sickling and membrane damage that cause vaso-occlusions and hemolysis. Sickle RBCs contain less adenosine triphosphate and more 2,3-diphosphoglycerate than normal RBCs, which allosterically reduces hemoglobin (Hb) oxygen (O2) affinity (ie, increases the partial pressure of oxygen at which hemoglobin is 50% saturated with oxygen [P50]), potentiating HbS polymerization. Herein, we tested the effect of investigational agent FT-4202, an RBC pyruvate kinase (PKR) activator, on RBC sickling and membrane damage by administering it to Berkeley SCA mice. Two-week oral FT-4202 administration was well tolerated, decreasing HbS P50 to levels similar to HbA and demonstrating beneficial biological effects. In FT-4202–treated animals, there was reduced sickling in vivo, demonstrated by fewer irreversibly sickled cells, and improved RBC deformability, assessed at varying shear stress. Controlled deoxygenation followed by reoxygenation of RBCs obtained from the blood of FT-4202–treated mice showed a shift in the point of sickling to a lower partial pressure of oxygen (pO2). This led to a nearly 30% increase in RBC survival and a 1.7g/dL increase in Hb level in the FT-4202–treated SCA mice. Overall, our results in SCA mice suggest that FT-4202 might be a potentially useful oral antisickling agent that warrants investigation in patients with SCA.

Positronium as a biomarker of hypoxia

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Paweł Moskal ◽  
Ewa Ł. Stępień
Keyword(s):  
Partial Pressure ◽  
High Sensitivity ◽  
Partial Pressure Of Oxygen ◽  
Physiological Processes ◽  
Positron Emission ◽  
Positronium Lifetime ◽  
Total Body ◽  
Living Organisms ◽  
Cancer Tissues

Abstract In this review article, we present arguments demonstrating that the advent of high sensitivity total-body PET systems and the invention of the method of positronium imaging, open realistic perspectives for the application of positronium as a biomarker for in-vivo assessment of the degree of hypoxia. Hypoxia is a state or condition, in which the availability of oxygen is not sufficient to support physiological processes in tissue and organs. Positronium is a metastable atom formed from electron and positron which is copiously produced in the intramolecular spaces in the living organisms undergoing positron emission tomography (PET). Properties of positronium, such as e.g., lifetime, depend on the size of intramolecular spaces and the concentration in them of oxygen molecules. Therefore, information on the partial pressure of oxygen (pO2) in the tissue may be derived from the positronium lifetime measurement. The partial pressure of oxygen differs between healthy and cancer tissues in the range from 10 to 50 mmHg. Such differences of pO2 result in the change of ortho-positronium lifetime e.g., in water by about 2–7 ps. Thus, the application of positronium as a biomarker of hypoxia requires the determination of the mean positronium lifetime with the resolution in the order of 2 ps. We argue that such resolution is in principle achievable for organ-wise positronium imaging with the total-body PET systems.

PrBa2Cu3Ox Polycrystalline Superconductor Preparation

1998 ◽  
Vol 12 (29n31) ◽  
pp. 3278-3283 ◽  
Author(s):  
W. L. Hults ◽  
J. C. Cooley ◽  
E. J. Peterson ◽  
J. L. Smith ◽  
Howard A. Blackstead ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Partial Pressure ◽  
High Temperatures ◽  
Sintering Temperature ◽  
Weak Ferromagnetism ◽  
Electromagnetic Properties ◽  
Oxygen Level ◽  
Partial Pressure Of Oxygen ◽  
Preparation Conditions

We prepared many samples of nominal PrBa2Cu3O x as ceramic, polycrystalline pellets with an enormous variety of preparation conditions and can confirm its superconductivity at T c = 89 K. We found that the superconductivity is in material with the YBa2Cu3O7 (YBCO) crystal structure. We observed weak ferromagnetism (canted antiferromagnetism) in samples prepared at high temperatures with a low partial pressure of oxygen; these samples also contained the phase PrBaO3 . The electromagnetic properties of the material depend sensitively on preparation conditions, especially the sintering temperature and the oxygen level.

Letter to the Editor

PEDIATRICS ◽  
1969 ◽  
Vol 43 (4) ◽  
pp. 638-639
Author(s):  
John H. Knelson ◽  
Mary Ellen Avery
Keyword(s):  
Partial Pressure ◽  
Oxygen Tension ◽  
Newborn Infants ◽  
Capillary Blood ◽  
Partial Pressure Of Oxygen ◽  
Oxygen Levels ◽  
Arterial Blood ◽  
Letter To The Editor ◽  
Ambient Oxygen

The letter from Drs. Stefan, Leschin, and Gray raises the important question of the validity of measurements of the partial pressure of oxygen (PO2) in capillary blood. We concur that measurements of oxygen tension are essential in monitoring ambient oxygen levels, and we would agree that, in the absence of shock, values on capillary blood reflect the levels in arterial blood. Fortunately, data exist, at least in normal newborn infants breathing air, that permit evaluation of the usefulness of capillary samples.

scholarly journals Lactate generation is not related to tissue partial pressure of oxygen levels in sepsis

Critical Care ◽  
2009 ◽  
Vol 13 (Suppl 3) ◽  
pp. P5
Author(s):  
AJ Pereira ◽  
P Rehder ◽  
C Dias ◽  
L Figueiredo ◽  
E Silva
Keyword(s):  
Partial Pressure ◽  
Partial Pressure Of Oxygen ◽  
Oxygen Levels

Fiber-optic probe for in vivo measurement of oxygen partial pressure

1984 ◽  
Vol 56 (1) ◽  
pp. 62-67 ◽  
Author(s):  
John I. Peterson ◽  
Raphael V. Fitzgerald ◽  
Delwin K. Buckhold
Keyword(s):  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Fiber Optic ◽  
Fiber Optic Probe ◽  
In Vivo Measurement ◽  
Optic Probe
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