Medical Carbonic Acid Carbon Dioxide

Recently, medical carbonic acid (CO2) has gained more and more importance in a number of medical helds of application. Especially in the promising field of minimal invasive surgery, the stabilization of visceral cavities (aeroperitoneum, pneumothorax) in laparoscopic and thoracoscopical interventions can not be imagined without the application of this gas - which in case of being correctly used reabsorbs easily. 

However, even the external application of medical carbonic add is of growing importance, as for example in sanatoria, where carbonic add baths have become firmly established for the successful treatment of certain dysfunctions of the cardiac and circulatory system as well as of the vascular system. 

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Zinc is an essential trace element and is commonly ingested as a nutritional supplement. Divalent zinc is one of the most important of the micronutrients. More than 100 enzymes are zinc dependent for example, carboxypeptidase, carbonic anhydrase (which is responsible for the exchange of carbonic acid in the blood and the exhalation of carbon dioxide), and the alcohol dehydrogenase (which metabolizes alcohol). Deficiency of zinc, especially in newborns, results in impaired growth, loss of hair, skin eruptions, and often impaired or delayed sexual maturation. Many medical problems are also associated with zinc deficiencies (e.g., ulcerative colitis, chronic renal disease, and anemia). 

A common medical recipe for a similar combination of ingredients is found in Alka Seltzer tablets these contain sodium hydrogen carbonate, citric acid, and aspirin. The acid and carbonate react in water to produce carbon dioxide, which gives the familiar fizz of Alka Seltzer. 

Another example of a biodegradable stent is the REVA (Reva Medical Inc., San Diego, CA), a tyrosine-derived polycarbonate, which after metabolism produces amino acids, ethanol, and carbon dioxide. The REVA is balloon expandable with a slide and lock design which allows the expansion of the stent without deformation (Figure 5C). Iodine is its source of radiopacity. It has thick struts of 200 microns. Preclinical data show complete re-endothelialization [81]. Currently, the paclitaxel-eluting REVA stent is under development. 

Chemical analysis is used to identify and determine the amount of chemical substances (Chapter 1) present in a sample. It is often used for forensic, medical and environmental purposes, and for quahty control in the food and chemical industries. Inorganic chemical analysis in secondary school involves the identification of cations such as zinc and lead(II), anions such as sulfate(VI) and iodide, and gases such as carbon dioxide and ammonia. It provides a context for the learning of the topics Acids, bases and s ts (covered in depth in Chapter 6) and Redox (Chapter 7), as the reactions in these two topics are relevant to the identification of cations, anions and gases. Chemical analysis also enables students to develop their process skills, such as manipulation, observation and the making of inferences. 

E.g., cadmium, which lies directly below zinc, and lead, which hes directly below tin, are both highly toxic. However, cadmium appears to be an essential element for at least one organism, a marine diatom that produces a cadmium-specific enzyme that catalyzes the conversion of carbon dioxide and carbonic acid, as discovered in the year 2000. For further biological information on this element, see J. Emsley, Nature s Building Blocks, Oxford University Press, Oxford, 2001, pp. 74—76. This book is the standard reference for the detailed properties of all the elements, including their human, medical, economic, historical, environmental aspects. 

Nicolas Deyeux (Paris March 1745-25 April 1837), professor of pharmacy in the medical faculty and of chemistry and pharmacy at the cole Centrale, pharmacist to Napoleon, an editor of the Annales de Chimiey also published on formic acid, the preparation of carbon monoxide by passing carbon dioxide over heated charcoal, and the extraction of beet sugar. 

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