Acid-base balance metabolic

Remer, T. (2001). Influence of nutrition on acid-base balance—metabolic aspects. Eur. J. Nutr. 40, 214-220. 

This electrolyte plays a vital role in the acid-base balance of the body. Bicarbonate may be given IV as sodium bicarbonate (NaHC03) in the treatment of metabolic acidosis, a state of imbalance that may be seen in diseases or situations such as severe shock, diabetic acidosis, severe diarrhea, extracorporeal circulation of blood, severe renal disease, and cardiac arrest. Oral sodium bicarbonate is used as a gastric and urinary alkalinizer. It may be used as a single drug or may be found as one of the ingredients in some antacid preparations. It is also useful in treating severe diarrhea accompanied by bicarbonate loss. 

For Further Reading J. A. Kraut and N. E. Madias, Approach to patients with acid—base disorders, Respiratory Care, vol. 46, no. 4, April 2001, pp. 392—403. J. Squires, Artificial blood, Science, vol. 295, Feb. 8, 2002, pp. 1002-1005. Lynn Taylor and Norman P. Curthoys, Glutamine metabolism Role in Acid-Base Balance, Biochemistry and Molecular Biology Education, vol. 32, no. 5, 2004, pp. 291-304. 

Hypothermia—Indirect cryodestruction Metabolic uncoupling Energy deprivation Ionic imbalance Disruption of acid-base balance Waste accumulation Membrane phase transitions Cytoskeletal disassembly Frozen State—Direct cryodestruction Water solidification Hyperosmolality Cell-volume disruption Protein denaturation Tissue shearing Intracellular-ice propagation Membrane disruption Microvascular Thawed State Direct effects... 

Excretion into urine of ammonia produced by renal mbu-lar cells facilitates cation conservation and regulation of acid-base balance. Ammonia production from intracellular renal amino acids, especially glutamine, increases in metabolic acidosis and decreases in metabolic alkalosis. 

Respiration—transport of oxygen from the lungs to the tissues and of COj from the tissues to the lungs Nutrition—transport of absorbed food materials Excretion—transport of metabolic waste to the kidneys, lungs, skin, and intestines for removal Maintenance of the normal acid-base balance in the body... 

Factors that can predispose patients to developing metabolic bone disease include deficiencies of phosphorus, calcium, and vitamin D vitamin D and/or aluminum toxicity amino acids and hypertonic dextrose infusions chronic metabolic acidosis corticosteroid therapy and lack of mobility.35,39 Calcium deficiency (due to decreased intake or increased urinary excretion) is one of the major causes of metabolic bone disease in patients receiving PN. Provide adequate calcium and phosphate with PN to improve bone mineralization and help to prevent metabolic bone disease. Administration of amino acids and chronic metabolic acidosis also appear to play an important role. Provide adequate amounts of acetate in PN admixtures to maintain acid-base balance. 

Chemoreceptor response to increased arterial hydrogen ion concentration. An increase in arterial hydrogen ion concentration, or a decrease in arterial pH, stimulates the peripheral chemoreceptors and enhances ventilation. This response is important in maintaining acid-base balance. For example, under conditions of metabolic acidosis, caused by the accumulation of acids in the blood, the enhanced ventilation eliminates carbon dioxide and thus reduces the concentration of H+ ions in the blood. Metabolic acidosis may occur in patients with uncontrolled diabetes mellitus or when tissues become hypoxic and produce lactic acid. An increase in arterial hydrogen ion concentration has no effect on the central chemoreceptors. Hydrogen ions are unable to cross the blood-brain barrier. 

Allen and DuBois136 have calculated that the R. Q. of 0.707, obtainable when fat is completely oxidized, would be lowered to 0.669 if the /3-hydroxybutyric acid were not metabolized. If more than one molecule of the ketone bodies is produced from one molecule of the fatty acid, as has been suggested,83 the R. Q. would be further lowered. This may be further complicated by a resulting upset in acid-base balance. 

Kidney Failure, Chronic An irreversible and usually progressive reduction in renal function in which both kidneys have been damaged by a variety of diseases to the extent that they are unable to adequately remove the metabolic products from the blood and regulate the body s electrolyte composition and acid-base balance. Chronic kidney failure requires hemodialysis or surgery, usually kidney transplantation. [NIH]... 

The balance of filtration at the glomerulus and reabsorption and secretion in the tubules allows the kidneys to maintain homeostasis of extracellular fluid, nutrients and acid-base balance and to excrete drugs and metabolic waste products. 

The kidneys main function is excretion of water and water-soluble substances (1). This is closely associated with their role in regulating the body s electrolyte and acid-base balance (homeostasis, 2 see pp.326 and 328). Both excretion and homeostasis are subject to hormonal control. The kidneys are also involved in synthesizing several hormones (3 see p. 315). Finally, the kidneys also play a role in the intermediary metabolism (4), particularly in amino acid degradation and gluconeo-genesis (see p. 154). 

Pharmacology Potassium participates in a number of essential physiological processes, such as maintenance of intracellular tonicity and a proper relationship with sodium across cell membranes, cellular metabolism, transmission of nerve impulses, contraction of cardiac, skeletal, and smooth muscle, acid-base balance, and maintenance of normal renal function. Normal potassium serum levels range from 3.5 to 5 mEq/L. 

Metabolic or respiratory acidosis Cautiously institute amiloride in severely ill patients in whom respiratory or metabolic acidosis may occur, such as patients with cardiopulmonary disease or poorly controlled diabetes. Monitor acid-base balance frequently. Shifts in acid-base balance alter the ratio of extracellular/intracellular potassium the development of acidosis may be associated with rapid increases in serum potassium. 

Mechanism of Action An electrolyte that is necessary for multiple cellular metabolic processes. Primary action is intracellular. Therapeutic Effect Needed for nerve impulse conduction and contraction of cardiac, skeletal, and smooth muscle maintains normal renal function and acid-base balance. 

It is not yet clear which estimates of the ratio between the levels of protein and of carbohydrate metabolism during hypoxia should be regarded as reliable. It seems likely that the increase in respiratory quotient in freshwater fish to values of 2.5-2.8, as found by Mohamed and Kutty (1983a, 1986), indicates a predominance of protein expenditure over that of carbohydrate. A hypoxic environment shifts the acid-base balance of the fish towards acidosis (Kotsar, 1976), thereby inducing the redistribution of electrolytes, alteration of ion exchange and the activity of Na+-K+-Mg2+-ATPases and alkaline phosphatases. It also leads to an increased level of C02 in the blood, which enhances the bicarbonate buffer system (Kotsar, 1976). In section 2.1, we... 

The primary functions of the blood may be considered in a broad sense to be the following (1) metabolic regulation—transport of oxygen, carbon dioxide, metabolites, hormones (2) physical and chemical regulation—temperature, acid-base balance, and osmotic pressure and fluid balance and (3) regulation of body defenses—protection against infection by the action of antibodies, leukocytes, and other mechanisms and prevention of hemorrhage. 

In the majority of cases, a UCD can be distinguished from other inborn errors of metabolism by routinely available clinical chemistry tests such as blood gases, acid/base balance, plasma glucose, ammonium, or lactate. Urea production, and hence serum urea nitrogen, is decreased in UCDs. Respiratory alkalosis has few causes and is an important diagnostic clue of hyperammonemia that should trigger measurement of plasma ammonium. 

Electrolyte balance Mineral balance Metal metabolism Acid-base balance Fluid balance Hematologic Mouth Teeth... 

Minerals include sodium, potassium, calcium, phosphorus, magnesium, manganese, sulphur, cobalt and chlorine trace minerals include iron, zinc, copper, selenium, iodine, fluorine and chromium. Their roles may be generalised within the areas of providing structure in the formation of bones and teeth, maintenance of normal heart rhythm, muscle contractility, neural conductivity, acid-base balance and the regulation of cellular metabolism through their activ-ity/structural associations with enzymes and hormones. The daily requirements of minerals can be obtained from a well-balanced diet. 

Mode of action. Acetylsalicylic acid is unique among NSAIDs in that it also irreversibly inhibits COX by acylating the active site of the enzyme, so preventing the formation of products including thromboxane, prostacyclin and other prostaglandins, imtil more COX is synthesised. Acetylsalicylic acid is rapidly hydrolysed to salicylic acid in the plasma. Salicylic acid also has an anti-inflammatory action but additionally exerts important effects on respiration, intermediary metabolism and acid-base balance, and it is highly irritant to the stomach. 

The protein and amino-acid metabolism of the liver is characterized by three essential functions (1.) production and breakdown of proteins, (2.) production and breakdown of amino acids as well as regulation of their concentrations in the blood, and (i.) detoxification of ammonium via the synthesis of urea (= excretory form) and glutamine (= non-toxic transport or storage form) with simultaneous regulation of the acid-base balance. The breakdown of branched-chain amino acids occurs only in the musculature by way of deamination, (s. pp 38, 43)... 

In 18 children with nalidixic acid intoxication, most of whom were aged under 1 year, the clinical effects were neurological disorders of alertness, hjrpertensive cranial syndrome, and neuronal damage some had a metabolic acidosis (30). Treatment included gastric lavage, correction of acid-base balance, and control of convulsions. 

Composite data from Muntwyler, E. (1968) Water and Electrolyte Metabolism and Acid-Base Balance, p. 14. Mosby, St. Louis, Missouri White, A., Handler, P, and Smith, E. L. (1973) Principles of Biochemistry, 5th ed., p. 802. McGraw-Hill, New York Long, C. (1961) Biochemist s Handbook, p. 670. Van Nostrand, Princeton, New Jersey. Reported ranges for some constituents are very wide. 

Burton, R.F., 1976. Calcium metabolism and acid-base balance in Helix pomatia. In S.P. Davies (Editor), Perspectives in Experimental Biology. I. Zoology. Pergamon, Oxford, pp. 7—16. 

The kidneys are critical organs. They filter wastes produced by metabolism from the blood and excrete them with water as urine. They are also major organs in whole body homeostasis, with acid-base balance, electrolyte concentration regulation, blood volume control, and blood pressure regulation functions. 

A description of acid-base balance involves an accounting of the carbonic (H2C03, HCOh COa", and CO2) and noncar-bonic acids and conjugate bases in terms of input (intake plus metabolic production) and output (excretion plus metabolic conversion) over a given time interval. The acid-base status of the body fluids is typically assessed by measurements of total CO2 plasma pH and PCO2, because the bicarbonate/carbonic acid system is the most important buffering system of the plasma. Occasionally, measurement of total titratable acid or base, or other acid and base analytes (e.g., lactate and ammonia [NH3]) is necessary to determine the etiology of an acid-base disorder. 

---