Tension polarographic oxygen

In the pioneer work of Updike and Hicks (40), the enzyme glucose oxidase (GOD) was maintained in a layer of acrylamide gel over a polarographic oxy n electrode (actually the Clark oxygen electrode). The current output of this probe results from the reduction of oxygen at a platinum electrode and thus is a function of the oxj n tension. When oxygen is not rate limiting and the glucose concentration is below the apparent for the immobilized GOD, there... 

Venous oxygen fluctuation under various influences were measured by Yokota and Kreuzer [64,65]. These authors have used polarographic oxygen electrode to the study of alveolar oxygen tension in alveolar gas and blood of anesthetized dogs [66,67]. 

Wong RK, Fyles A, Milosevic M, Pintilie M, Hill RP (1997) Heterogeneity of polarographic oxygen tension measurements in cervix cancer an evaluation of within and between tumor variability, probe position, and track depth. Int J Radiat Oncol Biol Phys 39 405 412... 

Radiometer pOz electrode, type E 5046 consists of a platinum cathode (20 /am diameter) and silver-silver chloride reference electrode placed in an electrochemical solution behind a 20 /am thick polypropylene membrane. A polarizing voltage of about 650 mV is applied. The polarographic current is about 10 " A per mm Hg of oxygen tension at 38°C. Zero current is lower than 10 A, response time less than 60 sec at 38°C 99% of full deflection. The PO2 electrode is used with the pH-Meter 27 GM or the Astrup Micro-Equipment, in conjunction with the Oxygen Monitor. The scale can be calibrated to the range 0-100 mm Hg p02. Thermostated cells provide measurements at constant temperature of volumes down to 70 /al. The small volume makes this cell useful to measure the PO2 of capillary blood. The cell is supplied with accessories for blood sampling. 

It is important to note that both the polarographic and galvanic electrodes measure the oxygen tension of the medium in which they are placed (Doran, 2013). So when an electrode is placed in a liquid, it does not measure dissolved oxygen, but rather the dissolved oxygen partial pressure, which is proportional to oxygen... 

The accessibility of primary and metastatic squamous cell carcinomas (SCC) of the head and neck for tumor oxygenation assessment has meant that these tumors have received considerable attention with a large number of studies already documented (see Table 4.5). Reliable Oj-sensitive polarographic electrodes for measurement of O2 tensions in head and neck cancers were first used by Gatenby et al. (1985,1988). These authors convincingly demonstrated that hypoxia in advanced tumors was associated with a poor prognosis. 

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