Warburg development

Nernst applied the electrical bridge invented by Wheatstone to the measurement of the dielectric constants for aqueous electrolytes and different organic fluids. Nemst s approach was soon employed by others for measurement of dielectric properties and the resistance of galvanic cells. Finkelstein applied the technique to the analysis of the dielectric response of oxides. Warburg developed expressions for the impedance response associated with the laws of diffusion, developed almost 50 years earlier by Fick, and introduced the electrical circuit analogue for electrolytic systems in which the capacitance and resistance were functions of frequency. The concept of diffusion impedance was applied by Kruger to the capacitive response of mercury electrodes. ... 

Introduction of photoelectric cells led to the replacement of the Duboscq colorimeter and so to quantitative spectrophotometric methods of analysis which met biochemical requirements. This introduction of spectrophotometry as a routine procedure was one of the earliest technological advances underpinning the elucidation of biochemical pathways between 1930-1960. Micromanometric methods also became available about the same time, and offered a means to measure cell respiration. Manometry was developed in Warburg s laboratory in Berlin and was one of the main techniques used by H.A. Krebs in his studies on the citric acid and urea cycles (Chapters 5 and 6). 

By the late 1920s quantitative micro-determination of oxygen uptake had been developed in Warburg s laboratory in Berlin based on a manometric technique introduced by Barcroft and Haldane (1902). With this equipment evolution of carbon dioxide or uptake of oxygen could be monitored Carbon dioxide produced in respiration was absorbed by potassium hydroxide. If bicarbonate buffer was used, acid production caused carbon dioxide to be released. Krebs and others from... 

In plant cell cultures, shake flask culture is an indispensable stage of cultivation. Investigations in a shake flask are very essential and critical to bioprocess scale-up and optimization. We have developed a simple and convenient technique based on the principle of the Warburg manometric method to measure 02 uptake rate (OUR) and C02 evolution rate (CER) of suspended cells in a shake flask culture. This technique has been successfully applied to suspension cultures of Panax notoginseng cells, and some important bioprocess parameters, such as OUR, CER, respiratory quotient (RQ), SOUR and specific CER (SCER), were quantitatively obtained [99]. As long as the environment temperature is strictly controlled to within an error of 0.1 °C, the measuring system is accurate and reproducible, is easy to operate, is economical, and is also able to treat many samples simultaneously. 

As an exercise, the reader can verify that equation (2.73) satisfies both real and imaginary parts of equation (2.70). This development represents the starting point for both the Warburg impedance associated with diffusion in a stationary medium of infinite depth and the diffusion impedance associated with a stationary medium of finite depth. 

Warburg s Formula for /Fp in Stationary Gas. Warburg (95) was interested in the relation between /FP and Bca FP, the rate coefficient with respect to charge transport (iucAt) for the total amount of reaction effected by a discharge in stationary gas enclosed within a volume t. The formula which he developed in 1900 can be restated as... 

A further development (related to Warburg s work) concerns what is called apoptosis, whereby billions of body cells perish each day to be replaced by new cells. There is an enzyme called apopain that determines whether the cells live or die. This enzymatic effect on apoptosis may possibly be inhibited or favored by an additive, which potentially may be of interest in the treatment of cancer. This again brings up the point that some of the myriad biologically active plant substances may act in such a way or other ways. 

In turn, Dr. Warburg addressed the latency period for transforming normal cells to abnormal ones, expressed in terms of sleeping cancer cells as follows Since the increase in fermentation in the development of cancer cells takes place gradually, there must be a transition phase between normal body cells and fully formed cancCT cells. The result is that we may have cancer cells which indeed look like cancer cells but are still energetically insufficient. Such cells, which are clinically not cancer cells, have lately been found not only in the prostate, but also in the lungs, kidney, and stomach of elderly persons. ... 

Additionally, Dr. Warburg made the following statement in 1%7 Because no cancer cell exists, the respiration of which is intact, it cannot be disputed that cancer could be prevented if the respiration of body cells could be kept intact. It was recommended by Dr. Warburg that the bloodstream be well supplied with oxygen, that high levels of hemoglobin be kept in the blood, and that the respiratory enzymes be kept at sufficiently high levels, say via the very foods we eat. It is emphasized that these protocols refer to the prevention of cancer rather than to the reversal of fully developed cancer. 

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