Concentrations Of Calcium Salts Research Articles

Chemical and morphologic characteristics of cholesterol gallstones that failed to dissolve on chenodiol: The National Cooperative Gallstone Study

During the National Cooperative Gallstone Study, chenodiol (chenodeoxycholate), 750 or 375 mg/day, resulted in complete gallstone dissolution in only 13.5% and 5.2% of patients, respectively. The purpose of this study was to analyze the composition and morphology of gallstones from patients who underwent cholecystectomy during the National Cooperative Gallstone Study to determine if calcium salts on the gallstone surface could have been responsible for failure of dissolution. Total gallstone calcium content was not different between the treated and placebo groups; however, surface calcium levels were different, being >1.0% in 47.6% of stones from chenodiol-treated patients (n = 63) but in only 16.7% of those from placebo-treated patients (n = 18), p < 0.02. Pigmented outer rims were found in 52.4% of the stones from the chenodiol-treated group compared with only 16.7% of stones from the placebo group, p < 0.01. The rim calcium content of 36 stones with pigmented outer rims was 3.7% ± 1.0%, whereas that of 45 stones with nonpigmented outer rims was only 1.0% ± 0.3%, p < 0.01. We conclude that the presence of rings of increased concentrations of calcium salts on the gallstone surface may impair dissolution by chenodiol.

Quantitative histochemistry of rat lumbar vertebrae following spaceflight.

Spaceflight has been shown to cause alterations in bone mineral content, bone growth, and resorption. In this study, the effects of return to gravity immediately and 6 and 29 days following spaceflight on bone of rat vertebral bodies were histochemically analyzed. Immediately postflight, there was no significant change in calcium salt content of the vertebrae, but 6 days later it was significantly decreased (P less than 0.05). By 29 days postflight, the calcium salt content had returned to normal. Postflight collagen content was not significantly altered. Keratosulfate was significantly higher (P less than 0.05) in trabecular bone of rats immediately postflight and 6 days postflight. Chondroitin sulfate was increased in vertebral bone on days 6 and 29 postflight. The histochemical patterns observed in this study suggest that bone turnover slows in vertebrae during spaceflight allowing bone ageing. The results support the contention that a form of osteolysis begins, immediately upon return to gravity, to remove components of old bone at which time mineral levels do decrease and levels of chondroitin and keratosulfates shift. The osteolysis phase is quickly followed by new bone replacement which is completed before 29 days postspaceflight.

Mineral content of growing bone (author's transl)

Normal mineral content of the calcaneus was determined in 137 healthy persons aged 3 to 20 years. Calcium-salt content increased with age, reaching 60% of its final value in the sixth year of life. In females mineralisation was practically complete in the 15th year.

The crustacean cuticle—II. Deposition of organic and inorganic material in the cuticle of Astacus fluviatilis in the period after moulting

1. 1. Three different regions of Astacus fluviatilis cuticle have been investigated with respect to changes in the content of calcium salts, chitin and protein during the first 2 weeks after moulting. 2. 2. The daily deposition of these substances during this period has been calculated, and the post-exuvial production is compared to that of the pre-exuvial. 3. 3. Amino acid analyses of the cuticle at different ages, from different regions, and of the organic matrix of the gastrolith are given. 4. 4. The findings are discussed in relation to other crustaceans and insects.

The crustacean cuticle—I. Studies on the composition of the cuticle

1. 1. The content of calcium salts, protein and chitin has been measured in the cuticle of Astacus fluviatilis, Cancer pagurus, Carcinus maenas, Leander adspersus, Nephrops norvegicus and Penaeus duorarum. 2. 2. The solubility and the amino acid composition of the cuticles have been determined. 3. 3. Comparisons are made between insect and crustacean cuticle and between the hardened and unhardened cuticle of Astacus.

The relation between the concentration of calcium salts in the urine and renal stone composition in patients with calcium-containing renal stones.

1. Diurnal variations in urine calcium oxalate and calcium phosphate activity products were observed in normal men and patients with recurrent calcium oxalate or mixed oxalate—phosphate renal stones. 2. Maximum and minimum calcium oxalate products were higher in the patients than in the controls, the difference being most marked in the patients with calcium oxalate stones. 3. Maximum and minimum calcium phosphate products expressed as octocalcium phosphate [(Ca8H2(PO4)6], brushite or hydroxyapatite, were significantly higher than normal in the patients with mixed stones but not in the patients with calcium oxalate stones. 4. The raised calcium oxalate products in the patients were due mainly to increased concentrations of Ca2+ ions; these, in turn, were due mainly to an increased rate of excretion of calcium. Raised calcium phosphate products were due mainly to hypercalciuria, combined with abnormally high urine pH values. 5. Patients with recurrent calcium stones appear to fall into two types: (1) patients with calcium oxalate stones associated with hypercalciuria, a normal or raised urine oxalate and a normal urine pH; (2) patients with mixed oxalate—phosphate stones associated with hypercalciuria, a normal or raised urine oxalate and a raised urine pH. 6. The implications of these findings in regard to treatment are discussed.

Flame photometric determination of strontium in silicates. Strontium content of the granite G-1 and the diabase W-1

A method for the determination of strontium in silicate materials by flame photometry is described, based on the standard addition technique. It takes background emission measurements into account and, where necessary, high concentrations of calcium salts are added to compensate for the depressing effect of aluminium. With this method, a strontium content of 258 p.p.m. in granite G-1 and of 151 p.p.m. in dibase W-1 was found. Precision and accuracy of the method are discussed.

V - The secretory phenomena in the oviduct of the fowl, including the process of shell formation examined by the microincineration technique

The present studies were commenced primarily to investigate the cytological phenomena in glandular tissues in which the secretion consists mainly of inorganic salts in solution. In selecting convenient material, the fowl uterus was chosen as a vertebrate organ liberating a secretion which, in view of the chemical composition of the egg shell, must contain calcium salts in high concentration with a trace of magnesium carbonate, but without significant amounts of iron, silicon, or aluminium. From previous investigations, it has been established that at least two types of gland cells exist in the lining epithelium of the uterus and that of the tubular glands of the uterine corium, both of which contribute to the final stages of egg-shell formation in the fowl. The addition of half the total egg-white, in the form of thin fluid albumen, has been conclusively attributed to the activity of the uterine glands, but no convincing localization of the egg-shell secretion has been made owing to the remarkably low concentration of calcium salts in the actively secreting uterus ; a concentration for which the ordinary histo-chemical tests are ineffective. The technique of microincineration, which hitherto has been confined largely to problems of a histological or embryological nature, owing to the difficulty of obtaining delicate cytological detail in the ash residues, was examined as a possible means of identifying the storage and elaboration of inorganic material in the uterine gland cells and its later extrusion as the mature secretion. A comparative examination of the mineral content of regions adjacent to the uterus and the cytology of heavy albumen secretion in the cranial sections of the oviduct, led finally to a study of secretory processes in the entire organ. The more important phases of the glandular activity in the infundibulum, albumen region, and the isthmus have been reinvestigated, particularly where lack of agreement exists, in recent literature, on details of major importance. A final solution, however, of many aspects of this problem naturally rests on the histo-chemical analysis of material fixed and sectioned without the use of protein precipitants or solvents. In this connection the new freezing-drying technique of Gersh (1932) might prove to be most suitable.

EXPERIMENTS ON CONTRACTION OF WHITE CONNECTIVE TISSUE FIBRES

1. In heat contraction of mouse‐tail tendon, localised swellings commence at certain points along the tendon. A partially contracted tendon has the appearance of a knotted cord with normal portions of tendon between the knots. Only when contraction is maximal is the whole tendon swollen.2. Immersion of the tendon in solutions of CaCl2 markedly affects the temperature at which contraction is induced. The higher the concentration of calcium salt, the lower the temperature at which the tendon will contract; with 48 per cent. of CaCl2 the tendon will contract at 0°C. The relation between concentration and temperature is approximately linear.3. Immersion in solutions of BaCl2 likewise affects the temperature at which contraction is induced. Thirty per cent. BaCl2 causes contraction at 38°C. The relation between concentration and temperature is again linear.The expenses of this research were defrayed by a grant from the James Cooper Fund of M'Gill University for Research in Experimental Medicine.

RESEARCHES ON THE PERFUSED HEART: SOME EFFECTS OF SODIUM CHLORIDE

An active displacement of calcium salts by sodium is a factor in the production of the diastolic failure which follows perfusion of isotonic sodium chloride through the frog's heart.After perfusion of isotonic sodium chloride through the frog's heart— 1. The action of calcium salts in shortening the refractory period, 2. The action of the same salts in producing tonus, 3. Their action in supporting the spontaneous contractions, is greatly increased in each case.Reasons are given for believing that these changes result from alterations in the state of aggregation of certain of the heart colloids.The changes of aggregation state induced by isotonic sodium chloride are, thus, favourable to these functional activities of calcium.Hearts perfused with mixtures of sodium and calcium salts eventually cease activity in diastolic failure, though this failure may be complicated by a primary increase of tonus. When examined at the end of this failure the heart shows a greatly diminished responsiveness to calcium salts. Reasons are given for believing this latter condition is due to the calcium salts in the original perfusing solution, and the conclusion drawn that calcium salts induce an aggregation state in certain heart colloids unfavourable to the more immediately apparent normal functional activity of these salts.The immediate stimulating effects of hypotonicity described by Carlson depend on the calcium salts in the perfusing solution. They vary in intensity according to the concentration of the calcium in the solutions. They are not due to hypotonicity per se, since they also occur if the osmotic pressure be kept constant by cane‐sugar. Removal of the restraint previously exercised by the sodium salts of the perfusing solution over its calcium is an important factor in this “stimulating action” of hypotonicity.Following on these primary changes are secondary ones in which the effective action of a given concentration of calcium salts in producing tonus, etc., is greatly diminished. On returning now to normal sodium chloride there is a sudden further diminution in the effective action of a given concentration of calcium, followed still later by a gradual and slow return towards the condition existing before the reduction in sodium chloride content.On perfusing a solution containing excess of sodium chloride (hypertonic), there is an immediate fall in the effective action of the calcium salts already present in the solution. Following on these changes the effective action of the calcium salts is greatly increased. The refractory period may be shortened sufficiently to permit of an apparently complete tetanus of the heart muscle. Summation of contractions is possible. The tonus may be greatly increased.On restoring the sodium chloride to normal there is a primary exaggeration of the effects just mentioned, the increased tonus changes sometimes simulating a “veratria” contraction. The effective action of a given concentration of calcium salts then decreases to a point where they may be less efficient than they had been before the hypertonic solution was perfused. After this overshoot the effective action of the calcium slowly returns towards the normal.The perfusion of a solution made hypertonic by adding cane‐sugar also increases the effective action of a given concentration of calcium, though not in similar degree to that induced by sodium chloride.Twofold relations exist in the heart between the salts of sodium and calcium. They are antagonistic in regard to their mutual adsorption on the surface of certain of the heart colloids (surface effects); they are antagonistic in regard to the changes in the state of aggregation each induces in those same colloids (deep effects). The state of aggregation induced by calcium is one unfavourable to its own activity in its function of tonus production, etc.; the state of aggregation induced by sodium favour these latter functions of calcium. The favouring action of sodium on these calcium functions outweighs its antagonism.Hence, if the amount of sodium chloride in a perfusing solution be increased, the effective action, in certain directions, of the calcium salts already present in that solution will also be increased, but at a distinctly later period, and vice versâ.In conclusion, I wish to express my indebtedness to Professor Sherrington for the facilities afforded me in carrying out this work.