Calcium

Calcium, Calcium, chemical element, symbol Ca, a shiny, silvery-white metal with a crystalline fracture, belonging to the group of alkaline earth metals. Specific gravity 1.53; atomic weight 40.07; melting point 808°. Ca belongs to the number of very common elements in the earth's crust. It is a component of limestone, calcite, aragonite, chalk, phosphorite, apatite, gypsum, alabaster, etc. It is found in plant and animal organisms. Calcium carbonate (CaCO₃) is contained in significant amounts in bones, occurs in nature in the form of chalk, calcite, and in the form of aragonite. It is found in almost every river and spring water. Water containing large amounts of Ca is called hard. Such water is little suitable for washing, as it forms insoluble lime soaps. Calcium silicate has wide technical application as a component of glass.

III Ca in organic nature. Ca is contained in all tissues and fluids of animal and plant organisms. Salts of Ca have a dual role: on the one hand, they serve as the main source of the formation of the supporting (skeletal) system of the organism, on the other hand, they actively participate in the development of a number of functional processes of the organism. The total content of Ca in the animal organism reaches 0.7-1.4% of body weight; at the same time, 99% of all Ca accounts for the skeletal system, and only 1% is contained in the soft parts of the organism. By organs, the content of Ca (in humans) is distributed as follows (in mg CaO per kg of weight of the corresponding organ): Muscles.....70-91, Spleen....130 Spinal cord . . 2 1

Bones contain approximately 152,000 mg of Ca. In the vast majority of cases, Ca is found in the organism in the form of inorganic salts, mainly phosphates, and only a small part of it is part of organic compounds. In the blood and tissue fluids, part of Ca is in an ionized state, and it is this part that actively participates in the life of the organism. Of the average total Ca content in the blood of 11.5 mg%, 2-3 mg% falls on dissolved ionized Ca; on complex complex compounds of Ca, charged negatively, 5-6 mg%; Ca in them is not ionized, but capable of dialysis; in this state Ca represents a kind of reserve, from which ionized Ca can be obtained; finally, the remaining 2.5-4.5 mg% falls on Ca adsorbed by proteins. The state of Ca in the form of a supersaturated solution is denied by most authors. The body's need for Ca depends mainly on age and the state of the body. The growing organism consumes significantly more Ca than the adult, in whom skeletal development is complete. In a number of pathological processes where there is a violation of calcium metabolism, the body's need for Ca and its content in the body change sharply (see also Calcareous deposits). The main source of Ca entry into the body is food. However, only a small part of dietary Ca is retained by the body, the larger part is excreted by the intestines and partly by the kidneys. The degree of retention of dietary Ca in the body is in inverse relationship to the magnesium content in it and in direct relationship to the phosphorus content in food. The average daily requirement for Ca for an adult according to Rubner's data is 1.0-1.5 g (CaO). With excessive introduction of Ca, for example with injections, part of it is retained by the bones (even in adults), and conversely, with insufficient introduction of it, the bones give up their own Ca and thus help maintain normal ionic equilibrium in the blood, in tissue fluids and in the cells of the body (see also Metabolism). Absorption and excretion of Ca represent complex processes (see Metabolism). The acidic reaction of intestinal contents, phosphates, fish oil and vitamin D (Stewart-Percival) favorably influence the absorption of Ca from the gastrointestinal tract, then the presence of carbohydrates, especially sugars, up to 50% of the total amount of food, and finally the presence of fats in food (the mechanism of their action has not yet been clarified). Ca is excreted (mainly in the form of phosphates) by the mucous membrane of the large intestine, and also partly by the kidneys. The intake of HCl increases the excretion of Ca with urine (Sollmann).

Role of Ca in the body. Besides the passive role of calcium salts in the body in terms of their plastic function, the ability of Ca and its compounds to activate enzymes, to vigorously influence the processes in the neuromuscular and vascular systems, and to participate in maintaining ionic equilibrium is of great importance for the body (see also Ions, physiological actions). The presence of Ca salts is necessary in nutrient media. Ca enters as an integral part into physiological solutions (Ringer's, Locke's) for surviving organs. Among the enzymatic processes, we note the formation of fibrin-ferment in the presence of Ca, while in the absence of Ca blood coagulation is impossible; citrate and oxalate prevent coagulation by precipitating Ca in vitro; in the body, however, the relationships are more complex, and sodium citrate is recommended as a hemostatic. Ca activates trypsin and the phagocytic function of leukocytes. The diuretic effect of Ca salts can be connected with its influence on the state of swelling of colloids; in this respect Ca is an antagonist of Na; Ca displaces Na from tissues (in non-nephritic, diabetic edemas). As experiments show, the excessive excitability, spasmodic and rhythmic contractions of skeletal muscles that occur in NaCl solutions can be stopped by the introduction of Ca salts. Glycosuria that occurs when a NaCl solution is introduced into the blood, as well as floridzin glycosuria, is decreased or even stopped by the introduction of Ca salts. The toxic effect on the development of Fundulus eggs in molecular solutions of NaCl can be neutralized even by very weak (molecular) solutions of CaCl2. In contrast to potassium, Ca increases the tone of the heart muscle and causes the systolic (and not diastolic, as potassium) phase of heart activity. Central nervous system narcosis and muscle paralysis from parenteral administration of magnesium salts can be stopped by the administration of Ca salts. The administration of Ca salts to animals (cats) in the region of the infundibulum cerebri leads to sleep and even a state close to narcosis, partly in contrast to potassium salts (Demole, Economo). Ca salts, in contrast to potassium salts, make the cell walls denser, less permeable; this is tried to be associated with the anti-inflammatory effect when Ca is administered (for example, by preliminary administration of Ca salts, it is possible to prevent or significantly alleviate acute inflammation and chemosis of the eye from mustard oil or dionin; by administration of Ca salts, it is possible to prevent the pleural effusion produced by iodine salts in animals). The peristalsis of the stomach in vivo is weakened by the introduction of calcium salts into the blood in contrast to potassium salts [sympathico- and vagotropine action (Unverricht, Freude)]. Based on experiments on the isolated heart of a turtle (Andrus), the heart of a frog (Gramenitsky), the stomach of a frog (Goldenberg), Ca ions must be recognized as more or less clearly expressed antagonists of H-ions and synergists of OH-ions. Views on the question of the effect of Ca on smooth muscle, especially vascular, differ. Isolated bronchial muscles increase their tone under the influence of Ca ( Trendelenburg). For the constriction of blood vessels of isolated internal and peripheral organs of warm-blooded and cold-blooded animals, the experiments of Gramenitsky speak. Opposite results were obtained by Regnier. The increase in blood pressure when Ca salts are introduced into the blood (as well as the results of kidney oncometry and the observed constriction of blood vessels) rather speaks for the vasoconstrictive, not vasodilatory effect of Ca; the systolic effect of Ca on the heart is apparently accompanied by a 'systolic' effect on the vessels, and the latter may be expressed with varying degrees of sharpness in the peripheral vessels and in the internal ones. Effect on the heart of calcium salts. Calcium salts increase the tone of the heart muscle and are a necessary condition for the heart system; make heterotopic centers of the heart more excitable ('third order' nodes, e.g. in the ventricles); preliminary passage of Ca sensitizes the heart to adrenaline. This action in many ways resembles the effect of irritation of the sympathetic nerves going to the heart; however, to fully identify the action of Ca and the effect of irritation of the sympathetic nerve, to consider Ca, so to speak, the 'chemical equivalent' of the physiological action of the sympathetic nerve (to which Zondek's theory leads), is in any case premature (O. Nikolaev). The action on the heart of Ca and substances of the digitalis group have much in common; Ca and digitalis mutually sensitize each other, acting on the heart; however, the complete identity in the mechanism of action of these substances is denied by most researchers. Denying the physiological identity in the action of Ca ions and the sympathetic nerve, it is still necessary to emphasize the 'sympathicotropine' of Ca, i.e. its intimate relationship, in many ways still not fully clear, to the functions of the sympathetic nervous system. Thus, the endings of the sympathetic nerves with a sharp decrease in Ca content or with its complete absence lose physiological excitability, which can result in increased function of antagonist nerves. When the n. splanchnici are cut, the Ca content in the blood falls, when the n. vagi are cut, it rises. On the whole animal, an excess of Ca ions as a rule leads to a decrease in excitability of the vegetative, especially sympathetic, nervous system; a decrease in Ca ions, on the contrary, is expressed by an increase in its sensitivity and excitability up to tetany (Sollmann). In general, fluctuations in the mutual ratio of different ions are a more important factor than fluctuations in the absolute amount of individual ions. Thus, for example, the same calcium effect on the heart can be obtained either by increasing the Ca content in Ringer's solution without changing the potassium content, or by decreasing the amount of potassium without changing the amount of Ca. In states of neuro-vegetative dystonias, the determining deviation from the norm in each case is not so much the absolute change in Ca content in the blood (e.g. its decrease when the vagus nerve is cut) as the change in the ratio of Ca to other ions.

in atonies), as well as a change in the coefficient (normal = 2). In vagotonia, significant increases in the coefficient are observed even with a relatively small decrease in the absolute amount of Ca, due to a simultaneous increase in potassium, which usually changes in the opposite direction. The constancy of the composition of serum cations is also determined by the coefficient, in which Ca also plays a major role, but which does not reveal the specific role of Ca and is not so closely related to vegetative dystonias. In normal conditions this coefficient is 27.6, in tetany it rises to 44.5 (KbPeg). The constancy of the ratio of Na:K:Ca ions in the internal environment of organisms, equal to approximately 100:2:2 (equilibrated salt solutions), and repeated at various stages of animal development, is of great importance.-A decrease in Ca in the blood (Ca is found in erythrocytes only in traces) is proven in parathyreoprivic tetany, spasmophilia, eclampsia of pregnant women; further-to a lesser degree-in osteomalacia, diabetes, pernicious anemia, scurvy, tbc. An increase in Ca (or bringing it to normal in parathyreoprivic animals) is achieved by the introduction of the parathyroid hormone; this increase in Ca in the blood is attributed mainly to the mobilization of bone Ca. Clinically, an increase in Ca in the blood is noted in ostitis fibrosa. In pathology, depletion of the body of Ca occurs in tetany, osteoporosis, osteomalacia; increased excretion of Ca in the urine-in genuine calciuria (so-called "phosphaturia") and secondary calciuria in many conditions of acidosis (neutralization of acids by lime); in many anemias and leukemias. The significance of decalcification in the pathogenesis of tbc is controversial (see Demineralization). In rickets, changes in the Ca content in the blood are atypical (the basis is a disturbance of phosphorus metabolism). Less commonly, there are processes with a delay of Ca salts (lime gout, overdose of vigantol and other Ca fixatives). Ca is often deposited in necrobiotic tissues (compare normal ossification of cartilage as a result of decreased vital activity, arteriosclerosis).-Among the symptoms after the introduction of Ca salts into the blood (partly based on experiments on humans), in addition to the already mentioned increase in blood pressure, bradycardia, vasoconstriction, pupil constriction (an early symptom, probably due to the direct action on the smooth muscle of the iris), a feeling of heat throughout the body, headache, and later with large doses-dizziness and fainting state; electrocardiographically, a more or less pronounced sinoatrial block is found. Determination of Ca (Kramer-Tisdall'H method). Principle of the method. The precipitation of Ca from serum or blood plasma is carried out by precipitating it with ammonium oxalate. The calcium oxalate formed is quantitatively determined by titration with a 1/100 solution of potassium permanganate. The amount of 1/100 potassium permanganate used in this titration is used to calculate the amount of precipitated calcium.-Necessary reagents. 1. Saturated solution of ammonium oxalate. 2. Saturated solution of ammonium acetate; the solution must be filtered. 3. 2% solution of ammonia. 4. 1/10 solution of sulfuric acid (can be not quite accurate). 5. 1/100 solution of potassium permanganate; prepare ex tempore from a 1/10 solution.-Method of determination. Into a centrifuge tube, 1-2 cm³ of serum (or plasma) is introduced, 1 cm³ of saturated ammonium oxalate solution (1) and 2 cm³ of ammonium acetate (2) (the reaction proceeds well in the presence of large amounts of ammonium salts). The contents of the tube are mixed with a glass rod and set aside for 1 hour, after which the precipitation can be considered complete. The mixture is then diluted with water so that the total volume of liquid equals 6 cm³. The liquid is mixed and centrifuged for 15-20 minutes. The liquid remaining above the precipitate is carefully removed with a pipette, and the precipitate is washed 3 times with a 2% solution of ammonia (3), 2-3 cm³ each time. After removing the last portion of washing liquid, the washed precipitate is dissolved in 2 cm³ of sulfuric acid (4), heating the tube in a boiling bath, and titrated with a 1/100 solution of permanganate (5). Titrate until a pink color appears that does not disappear for 1 min. The amount of precipitated Ca is calculated by multiplying the total number of cm³ of potassium permanganate used by 0.2, since each cubic centimeter of the latter corresponds to 0.2 mg of calcium. Therapeutic application of Ca. The main indications for Ca therapy are tetany (especially parathyreoprivic), spasmophilia, renal edema and hemorrhagic nephritis, various forms of osteopathy; further-chronic infections, e.g. tbc, especially those accompanied by symptoms of irritative weakness of the nervous system; bronchial asthma, membranous colitis, hay fever, urticaria, Quincke's edema, various skin diseases, e.g. lupus erythematosus, various inflammatory edemas (lungs, larynx, angioneurotic edema, urticaria); hemorrhages of various origins; Raynaud's disease; anaphylactic phenomena; as a preventive measure before bloody operations. The main contraindications are considered to be high blood pressure and pronounced arteriosclerosis; the first contraindication can hardly be considered absolute, as some forms of hypertension are treatable with calcium.-The clearest and most certain therapeutic successes have been achieved in parathyreoprivic tetany, spasmophilia, urticaria, migraines; in these cases the obvious deficiency of Ca in the blood with all its unfavorable consequences is replenished by the administered Ca, and the therapy proceeds according to the "replacement therapy" method, giving a quick effect, although perhaps not deeply affecting the very cause of the disease. In addition, Ca is used in heart diseases, especially those accompanied by loss of cardiac muscle tone and dilation; to enhance the systolic action of substances of the digitalis group; in diarrhea, especially on a fermentative basis (binding of fatty acids).-In most other cases, the clinical results of calcium therapy are not so clear-cut, sometimes controversial and must be evaluated from various points of view. First of all, it must be proven that the Ca content in the blood increases not only with intravenous administration, but also when given per os, especially on an empty stomach; with a Ca dose not exceeding 1-2 g, it is possible to increase the Ca content by 1-2 mg% for 3-4 hours; with doses of 5-6 g, a greater increase was achieved-4-5 mg%, maximum 8 mg%; with repeated doses it is possible to maintain the blood Ca at elevated levels (Fraser et al.). More important therapeutically is the increase in ionized Ca, rather than its total amount; in this regard, it is worth mentioning that by creating a temporary acidosis, e.g. with large doses of NH4Cl, it is possible to increase the content of total and ionized Ca in the blood (Bernard). Furthermore, the effect of Ca on circulation, its "anti-inflammatory" property ("physiological thickening" of cell membranes), its effect on enzymes involved in phosphorus and calcium metabolism (phosphatases, blood clotting enzymes, etc.), binding of fatty acids, as well as the condition of tissues, their need for Ca, the ability of Ca salts (e.g. CaCl2) to cause acidosis, etc., must be taken into account.-Other indications for the use of Ca preparations, where one does not count on the specific action of the Ca ion, but where the main role is played by either the alkalinity of the compound [e.g. Ca(OH)2], or the anion (e.g. CaI2, CaBr2), or the salt effect; sometimes only the mechanical action of Ca compounds is counted on (e.g. CaSO4 for surgical dressings). When conducting calcium therapy, it is important to simultaneously use dietary and actinic factors that promote the fixation of Ca by the body (mountain sun, vitamins, cod liver oil, vigantol). Preparations of Ca. 1. Calcium oxydatum, Calcaria usta (Ph VII), calcium oxide, burnt lime, CaO; amorphous hard pieces of white or grayish-white color, considerable hygroscopicity; heat up and swell when poured with half the amount of water, giving a white powder of calcium hydrate [Ca(OH)2]. Used for disinfecting privies, for neutralizing poisons when poisoning the soil, etc. - 2. Calcium causticum, s. Calcium oxydatum hydricum, Ca(OH)2, slaked lime; formed when slaking burnt lime with cold water; white powder of strongly alkaline reaction, dissolves in 750 parts of water. Freshly obtained slaked lime is used for disinfection, like the previous preparation. - 3. Aqua Calcis. (See Caustic alkalis.) - 4. Linimentum Calcis. (See Caustic alkalis.) -5. Calcaria saccharata, s. Saccharum calcareum, sugar lime, colorless flakes or white powder of sweet alkaline taste; slowly soluble in water (1:12).

Orally 0.5-1.0 with sugar water in children for rickets and diarrhea; as an antidote in poisoning by mineral acids, phenol, and oxalic acid, calculated for neutralization of acids and formation of insoluble compounds. - 6. Calcaria chlorata, Calcium hypochlorosum (Ph. VII), chlorinated, chloric, or bleaching lime, chemical compound of calcium hypochlorite and calcium chloride + water; obtained by passing chlorine through caustic, i.e., slaked lime at ordinary temperature: 2Ca(OH)2 + 2Cl2 = Ca(ClO)2 + CaCl2 + 2H2O. Must contain not less than 25% detachable, i.e., active chlorine. Whitish dry powder, smelling of chlorine, partially soluble in water. Solutions of chlorinated lime are unstable and must be freshly prepared. Used for disinfection of excrements, for eliminating odors, for gargles, in the treatment of wounds, for washing the eyes; for the latter purpose, Dakin-Carrel solution is more often recommended - a 0.5% solution of chlorinated lime with the addition of soda and boric acid for neutralization. This preparation is more convenient, being less irritating and more uniformly releasing chlorine. Chlorinated lime, mixed with ammonium chloride, may cause an explosion. - 7. Calcium sulfuratum, s. Calcaria sulfurata, calcium sulfide, lime-sulfur paste, light gray powder, smelling of hydrogen sulfide in the presence of water; sparingly soluble in water; used mainly for depilation in ointments and pastes. Liquor Calcii sulfurati, Solutio Vleminckx, Vleminckx's solution (Calcaria usta 1 part, Sulfur depur. 2 parts, Aquae 20 parts, evaporated to obtain 12 parts of filtrate) is used for washings in scabies and similar purposes. --8. Calcium bromatum (CaBr2), bromide of calcium, white, bitter-salty taste, odorless granular powder, easily soluble in water and alcohol; doses - 1.0-2.0 several times a day, mainly as a sedative, calculated for Br. - 9. Calmonal, compound of Ca, bromine, and urethane; used mainly as a hypnotic in 1.0 tablets.-10. Sa lc i o d a -tum (CaI2), yellowish powder, easily soluble in water; used as a substitute for KI, as well as in scrofula; doses 0.02-0.05-0.1-0.2.-11. Sa lc i urn carbo-nicum praecipitatum, precipitated calcium carbonate, precipitated chalk, CaCO3 (ФУП); white powder, odorless and tasteless, insoluble in water, easily soluble in acids with evolution of CO2; enters into the composition of dental powders; used in the form of dusting powder and internally for neutralization of acids and against diarrhea.-12. Calcium sulfuricum. (See Gypsum.)-13. Calcium chloratum crystalli-satum (Ph. VII), crystalline chloride of Ca, CaCl2.6H2O, colorless prismatic crystals of bitter taste, extremely hygroscopic, deliquescent in air; dissolve in 1/2 part of water, neutral reaction. Formed by dissolving calcium hydrate in hydrochloric acid. Used very frequently for all indications for typical calcium therapy; doses from decigrams to 5 g and even higher per os in aqueous solutions; cannot be injected subcutaneously due to irritating and even necrotizing action. For intravenous injection, the average dose should be considered about 1 g; injected in 5-10% solution or, as many prefer, in 1% solution. Used for dehydration of various compounds and drying of gases.-Calcium chloratum granulatum - anhydrous granulated (granular) calcium chloride, composition CaCl2.-15. A f e n i 1, aqueous solution of the compound CaCl2 with urea; suitable for intravenous and intramuscular injections; in 10 cm3 contains approximately 0.6 CaCl2; used for all typical indications for calcium therapy.--16. Na-mosistan, compound of CaCl2 with ethylenediamine acetate. In the form of 2% solution used intravenously to increase blood coagulability.-17. Sa l z i n, solution of 0.5 CaCl2 and 1.0 gelatin in 10.0 water, used for intravenous and intramuscular injections.-18. Cal-z a n, compound of calcium lactate and sodium; in tablets and powders, in doses 0.5-1.0 and higher; the introduction of sodium is intended to increase the alkalinity of the blood.-19. A g i t, in the form of dragees, containing 0.135 acetyl-salicylic acid, 0.045 calcium salicylate, and 0.045 calcium lactate; antineuralgic and anti-inflammatory remedy; the introduction of calcium is intended to weaken the poisonous action of salicylic acid on the kidneys and small vessels.-20. Calcium-Diuretin in tablets of 0.5 several times a day; contains 11% Ca, 48% Theobrommi and 38% Acid. salicylici; especially recommended for essential hypertension and asthma.-21. Sa lc i -g l y u s i n, product of combining 1 part CaCl2 with 2 parts glycine; easily soluble in water; in tablets (containing 0.2 CaCl2); used in osteomalacia.-22. Calcium glyce-rinophosphoricum, C3H5(OH)2O.PO(O2Ca).2H2O, Calcium glycerophosphoricum (Ph. VII), calcium glycerophosphate; white powder, soluble in 40 parts of water; widely used as one of the preparations for calcium therapy, as well as for increasing the tone of the nervous system.-23. Calcium phosphori-cum (CaHPO4.2H2O) (Ph. VII), calcium phosphate; white powder, almost insoluble in water; taken internally in chronic diarrhea and rickets in doses of 1.0-2.0-5.0 per dose.-24. Calcium lacti-c u m, calcium lactate; white powder, dissolves in 9.5 parts of water; especially recommended for rickets and scrofula and for stopping hemorrhages from the upper respiratory tract in doses of 0.5-2.0-4.0 per dose several times a day.-25. Calcophy-s i n, combination of calcium salts with extract of the infundibular part of the pituitary gland; recommended for stopping uterine hemorrhages; used either in the form of tablets, one 1-3 times a day, or in the form of solutions of 3 cm3 for intravenous injections.-26. Calcoprotin, compound of calcium oxide with albumoses; yellowish powder; take a teaspoonful to a glass of water in increased acidity in the stomach.-27. Co r d i c a l, preparation containing calcium salts and digitalis; each tablet contains 0.05 of standardized digitalis and 0.2 of calcium salt.- 28. Jod-Calcium-Diuretin, especially recommended for anginal and asthmatic conditions, in tablets several times a day.