Brain oxygen requirements

In addition to highlighting the basic results of the mathematical analysis outlined above, this paper presents the results of some important ancillary findings. Oxygen consumption of the sample was measured as an indication of the physiological state of the brain tissue. Requirements for certain components in the exposure medium are emphasized. Finally, we discuss mechanisms that may be responsible for the RF-induced calcium-ion efflux from brain tissue. 

The low concentration level of I in brain samples requires sensitive analytical methods. At the Jozef Stefan Institute, Ljubljana, several techniques have been developed for the determination of in different biospheric samples using a short irradiation to induce 1 (Dermelj et al, 1990). One RNAA method was applied for human brain analysis in NAAL-Berhn (BER II Reactor). The method consists of burning the activated samples in an oxygen atmos-ph ere and separating I using oxidation—reduction and extraction cycles, while chemical yield was determined by spectrophotometry for each sample, using recovery of the elemental iodine carrier. Details of the procedure have been pubhshed 2004 (Andrasi et al., 2004). 

During the process of respiration oxygen is transferred from the air to the body cells and carbon dioxide is disposed of in exhaled air. Because body cells function at different rates their oxygen requirements vary from one tissue to another. If brain cells are starved of oxygen for more than four minutes there is little prospect of recovery of intellectual function. Other body cells can do without oxygen for longer periods of time. 

The energy needed to transport ions across the membrane is obtained by the cell in chemical reactions occurring in it that is, the oxidation of organic substances with oxygen (for more details, see Section 30.2). Every second about 10 to 10 ions are transported across 1 m of membrane area. This process requires 20 to 30% of all energy generated by the cell. It has been calculated that the total power of the ionic pumps in the cells of the brain is about 1 watt. 

---