Dextrose mechanisms

Hypercapnia (abnormally high concentration of carbon dioxide in the blood) can develop as a result of overfeeding with both dextrose and total calories.1,37 Excess carbon dioxide production and retention can lead to acute respiratory acidosis. The excess carbon dioxide also will stimulate compensatory mechanisms, resulting in an increase in respiratory rate in order to eliminate the excess carbon dioxide via the lungs. This increase in respiratory workload can cause respiratory insufficiency that may require mechanical ventilation. Reducing total calorie and dextrose intake would result in resolution of hypercapnia if due to overfeeding. 

The colour reaction with fuchsine-sulphurous acid provides a means of distinguishing sharply between aldehydes and ketones. In dilute aqueous solution dextrose reacts negatively. Concerning the mechanism of the colour reaction see Ber., 1921, 54, 2527. 

Carmustine infusion solutions are administered over a period of one to two hours by slow infusion. The stability of carmustine, a nitrosourea derivative, after reconstitution and dilution depends on pH, temperature, radiation exposure, and sorption of delivery devices. Because of the pH factor, diluted solutions are more stable in 5% dextrose injection than in 0.9% sodium chloride injection. Different degradation mechanisms exist for the photoexposed and dark reactions. 

Figure 4. Mechanism of RO in the marketplace. The pore size is approximately equal to twice the thickness of the pure water layer over the membrane which is void of any ions. This membrane, when constructed of CA, typically will remove over 99% of the organics in excess of 200 mol wt and removes over 98% of monosaccharides such as dextrose and glucose.

It has been found by further investigation that there is apparently another step in the fermentation reaction in which the dextrose di-phosphate splits into two moles of triose mono-phosphate. It should be particularly noted that the immediately preceding study of the mechanism of the action of yeast juice is not directly applicable to the action of yeast. E.gSlator (loc. cit.) found that phosphates are without accelerating effect when living yeast cells are employed. 

The "solution-diffusion" model explains why molecules larger than salt sometimes pass through an RO membrane more readily. For example, cellulose acetate membranes which show a 95% rejection for NaCI (MW 58) and a 99% rejection for dextrose (MW 180), show a negative -34% rejection for 2,4-dichloro-phenol (MW 163). This means the dichlorophenol passes through the membrane more readily than water. This is hard to explain with a "pore-flow" sieving mechanism. 

FIGURE 25.6 Impact of five variables on flow rate accuracy in four different infusion pumps. Variables tested included solution Distilled water and 25% dextrose in water, back pressure -100 and 300 mm Hg, pumping segment filling pressure -30 inches of water and -1-30 inches of water, temperature 10°C and 40°C, and infusion rate 5 mL/h and 500 mL/h. Note First and second peristaltic mechanism qualified for low-risk patients, while the third peristaltic device qualified for high-risk patients. 

The effect of the crystal habit-forming impurities, raffinose, dextrose, and potassium chloride on the growth of sucrose crystals from various seeds has been studied. A mechanism for the oxidation of o-galactose by Nessler s reagent in alkaline media via the enediol has been proposed on the basis of kinetic measurements. The reaction is zero-order with respect to Hg" and first-order with respect to galactose. The rate is inversely proportional to the concentration of iodine ion. 

Nevertheless, having shown that the senun cholesterol concentration can be exchanged by the type of carbohydrate eaten the possible mechanisms whereby this is achieved must be considered. One possibility that has been explored is that the rate of secretion and composition of bile is affected. In 1919 it was discovered that sucrose, in the diet of dogs with a bile fistula, suppressed bile acid excretion (Foster et al., 1919) and this was found to be true in rats where both sucrose and dextrose decreased cholic acid in the bile whereas cornstarch did not affect the level (Portman et al., 1955). The half-life of cholic acid was also influenced by the type of dietary carbohydrate (Portman and Murphy, 1958). In a series of experiments on hamsters it has been shown that young animals on a fat-free diet have a marked tendency to form cholesterol gallstones when the dietary carbohydrate was dextrose and showed no such tendency when the carbohydrate was starch (Dam and Christensen, 1961). 

Another possible mechanism for the effect of dietary carbohydrates on cholesterol metabolism is that the carbohydrates affect the absorption of cholesterol. Dietary fructose with cholate gave rise to a hypercholesterolemia in rats, cornstarch was not very effective in this regard, and sucrose and dextrose were intermediate (Portman et al., 1956b). Sucrose favors cholesterol reabsorption in chicks when compared with glucose (Grant and Fahrenbach, 1957) and in rabbits lactose gives rise to more reabsorption than sucrose (Wells and Anderson, 1959). 

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