Glucose

GLUCOSE (syn.: dextrose, grape sugar), C₆H₁₂O₆, belongs to the group of hexoses (i.e., carbohydrates having 6 carbon atoms in their particle), specifically to the group of aldoses (see), as it is an aldehyde of the hexahydric alcohol sorbitol. Glucose is an optically active substance and can exist in the form of three stereoisomers: dextrorotatory - d-glucose, levorotatory - l-glucose, and optically inactive, racemic - d,l-glucose. d- and l-Glucose differ from each other by the unequal spatial arrangement in their molecule of the "H" and "OH" groups around asymmetric carbon atoms (see Asymmetric carbon): CHO

CHO H-C-OH

HO-C-H HO-C-H

H-C-OH H-C-OH

HO-C-H H-C-OH

HO-C-H CH₂OH

CH₂OH d-glucose

l-glucose. In animals and plants, only the d-stereoisomer of glucose is found, for which [a]_D = +52.6°. Glucose is easily soluble in water and less sweet than cane sugar. Glucose, upon reduction, turns into the alcohol sorbitol. Upon oxidation with weak oxidizing agents, glucose yields gluconic acid CH=O(CH.OH)₄.COOH, and upon stronger oxidation - saccharic acid COOH(CH.OH)₄.COOH. Glucose is very common in nature, partly occurring in a free state (in grapes, sweet fruits, roots), partly entering into the composition of disaccharides (sucrose, lactose), polysaccharides (starch, glycogen, plant fiber), glycosides, tannins, esters with phosphoric acid (see Hexosephosphoric acids).

Glucose, which has split off during the digestion of food di- and polysaccharides, is absorbed. Glucose is always contained in the blood (in the blood of healthy people on average - 0.083-0.092%; the extreme limits of glucose content in the blood of healthy people are 0.063-0.116%). The glucose content in the blood can increase both when eating large amounts of carbohydrates at once (especially glucose or disaccharides), when the liver does not have time to retain them, converting them into glycogen (see) (in this case, they speak of alimentary hyperglycemia), and in various diseases associated with disorders in carbohydrate metabolism processes (in diabetes, in avitaminosis); in other cases, the glucose content in the blood can, on the contrary, decrease (e.g., after the administration of insulin). Therefore, the determination of glucose content in the blood has great diagnostic significance. In other fluids and tissues of animal bodies, glucose is contained in the form of traces. In the urine of healthy people, glucose is also contained in the form of negligible traces, which are not detected by ordinary sugar tests (i.e., it can be said that practically in the urine of healthy people, glucose is absent); but in various diseases (e.g., in diabetes mellitus) glucose can be contained in the urine even in very large quantities. During alcoholic fermentation, glucose turns (passing through a number of intermediate stages) into alcohol and carbonic acid. In the animal organism (e.g., in muscles), the final products of glucose oxidation are water and carbonic acid, and here too, a whole series of intermediate products is formed first. Qualitative reactions for glucose are based mainly on its ability to reduce metal oxides; such are, for example: Trommer's or Fehling's test - reduction of copper oxide to cuprous oxide, Böttger-Nylander's test - reduction of bismuth oxide to metallic bismuth, reduction of silver oxide. Other reactions are the preparation of glucosazone, the fermentation test, and polarimetric examination. With the help of all these reactions, one can detect the presence of glucose in urine. Quantitative determination of glucose content in urine and blood is performed using various methods, also based on the reducing ability of glucose. For urine, the Fehling-Pavy method is most often used. The glucose content in the blood is most often determined by the Bang or Hagedorn-Jensen method. There are also colorimetric methods (Folin, Benedict).

Palladium. Clinical application of glucose. Glucose is used in clinical practice for both diagnostic and therapeutic purposes. Couturier attempted to determine liver function based on the amount of sugar excreted in the urine after administering 100 g of glucose orally; for the same purpose, Baudouin studied blood sugar levels after a glucose load (see Liver, functional diagnosis). Umber, Rosenberg, and others also used the glucose loading method, but with the aim of evaluating the function of the insular apparatus of the pancreas based on the blood sugar curve; further development of the glucose loading method can be found in Hagedorn, who began to study the relationship between capillary and venous sugar [see Pancreas (functional diagnosis of the insular apparatus), Metabolism, carbohydrate]. Subsequently, for diagnostic purposes, at the suggestion of Morris (1921), glucose began to be used in clinical practice to detect hyperthyroidism. According to Friedenwald and Grow, blood sugar in cancer patients, which rises sharply after administration of 100 g of glucose, does not return to its original level after 2 hours. There is no unity of views on the value of the data obtained after loading. The blood sugar curve and data from urine sugar analysis depend on too many factors to consider it possible to unconditionally use the data obtained after glucose loading in clinical practice. Therapeutic application of glucose. The physiological basis for the therapeutic effect of glucose is not fully understood. Experiment and observation at the patient's bedside have preceded theory in this matter. From experiments with a surviving heart, it is known that adding glucose to the nutrient solution can increase heart performance (Locke). Winterstein's experiments with the frog's spinal cord showed that sugar is consumed by the nervous system. The study of metabolism establishes the role of glucose as a factor that spares proteins from breakdown; in general, the therapeutic role of glucose is probably determined by its nutritional value and the ease with which the body can use it as fuel material. For this purpose, Budingen uses intravenous administration of glucose in cases of heart weakness (10-12% solution in amounts of 200-250 cubic cm twice a week), believing that this weakness may be due to insufficient nutrition of the heart muscle. Many clinicians have confirmed the success of the therapeutic application of glucose in terms of improving subjective symptoms, but most deny objective success. Furthermore, hypertonic solutions of glucose (40%-20 cubic cm) are used by some physicians in pulmonary edema of various etiologies (Jagic and Klima). The proposal to administer glucose in angina pectoris deserves some attention. The success of treatment is manifested in the cessation of the feeling of pressure in the heart area. In diabetes mellitus, when coma has already developed, administration of glucose may be necessary (see Diabetes mellitus, treatment); similarly, in severe cases of hypoglycemia (hyperinsulinemia), it is necessary to resort to the rapid and reliable administration of glucose. To combat postoperative acidosis, at the suggestion of Thalhimer (1923), some surgeons began to prepare patients for surgery by administering 500-1,000 cubic cm of 10% glucose solution into a vein (together with insulin under the skin, in two doses, five minutes before the infusion and immediately after its completion, in the amount of 1 insulin unit per 3.0 g of glucose administered). Administration of 20 cubic cm of 50% glucose solution 12 hours before anesthesia (according to Trenkhoft and Kutscha-Lisberg) shortens the period of excitement, reduces vomiting, and allows the use of a smaller amount of narcotic substances. The easy assimilability of glucose has prompted its use as a nutrient, added to the diet in such quantities that the daily ration has the desired caloric value; unfortunately, the high cost of the drug makes this proposal impractical (Bennett and Dodds), and at present, in some cases of emaciation, cane sugar can be usefully used for fattening, which is administered after injection of small doses of insulin. The attempts to use glucose in liver diseases, namely in acute yellow atrophy of the liver, in catarrhal jaundice, hepatitis, and cirrhosis, with or without simultaneous administration of insulin, undoubtedly represent practical interest. In chronic kidney diseases, treatment with sugar, and in particular with glucose, is also possible; Pribram recommends it especially in uremia. The ability of glucose to reduce the toxic effect of many medicinal substances (and in some cases to enhance the therapeutic effect) has been noted; hence Prantner's proposal to administer salvarsan in 20 cubic cm of 25% glucose solution, glucose with disparogen (Weitgasser), glucose with tripaflavin (Latzel), etc., or for example strophanthin with glucose solution. This does not exhaust the list of proposals for the application of glucose. In response to the administration of glucose, acceleration of blood clotting and increased diuresis have been noted; this symptomatic effect of glucose can also be utilized. The use of glucose also has its contraindications; besides cases of decreased tolerance to it, intravenous administration of glucose is contraindicated, according to Budingen: in cases of tendency to embolism, in widespread sclerosis of the brain, especially after apoplexy, in severe coronary sclerosis. Unpleasant consequences of intravenous administration of glucose may be a shaking chill (Schenk), a flare-up of old inflammatory foci (Stepkal and Latzel). Glucose is prescribed in very different doses and administered in various ways: for example, orally or through a duodenal tube, 50.0-100.0-150.0 or more grams are given at one time in one glass of water; per rectum, a 4.5-5% solution is administered in the form of a drip enema in amounts of several hundred cubic cm of solution; subcutaneously, 6-10% solutions can be safely administered, but due to their somewhat irritating local effect on tissues, intravenous administration is preferable; into a vein, usually 500 cubic cm of isotonic glucose solution (5%) is administered, and in some cases smaller amounts (20-60 cubic cm) of hypertonic solution (for example, 10-35% and even 50% glucose solution). Some physicians prefer to use factory-made glucose preparations instead of solutions prepared on the spot, which require a guarantee of their sterility. The glucose solution used for infusion must, of course, be carefully prepared (from chemically pure sugar on freshly distilled water) and must be sterile. The infusion is performed according to general rules; it should be especially noted that intravenous infusion of glucose must be done slowly due to the possibility of thrombosis of the veins.

v. Rubinstein.