Differences In Calcium Content Research Articles

EFFECT OF LIPID PEROXIDATION ON PHOSPHOLIPASE A2 ACTIVITY OF RAT LIVER MITOCHONDRIA

Effect of lipid peroxidation on phospholipase A1 activity was examined in rat liver mitochondria. Content of lipid peroxides in rat liver mitochondria was markedly increased in the presence of ascorbic acid (0.1 mM) and ferrous ion (40 muM, as compared to the control. Phospholipase A2 activity in mitochondria was activated by approximately 60% after lipid peroxidation. Mg2+-activated ATPase activity in mitochondria was markedly stimulated by about 200% following treatment with ascorbic acid and ferrous ion. There was no difference in calcium content of mitochondria before and after lipid peroxidation.

The mineral composition of apples. Calcium concentration and bitter pit in relation to mean mass per apple

AbstractData for bulked samples of ungraded Cox's Orange Pippin fruit obtained from many sources over a period of 18 years show that there is a general inverse relationship between mean mass per apple and mean calcium concentration. Part of the scatter around the regression curve was accounted for by differences between years but there were larger differences between samples of the same size picked from different orchards in the same year. Even with the most favourable conditions the observed samples with mean mass per apple greater than 150 g had less than 5 mg Ca/100 g when no calcium sprays were applied and in general most samples with mean masses per apple greater than 110g were likely to have concentrations of calcium below this and hence were liable to develop bitter pit. Fruit calcium level was a more important determinant of liability to bitter pit than was mean mass per apple.Although there was some evidence of the same relationship between calcium concentration and mass when apples from the same tree were analysed individually other factors often negated it. Two‐ to three‐fold differences in calcium concentration were observed in individual apples from the same tree.

Difference in calcium content of atrial and ventricular muscle.

The calcium content and inulin space of the atrial and ventricular muscle were determined in isolated perfused heart of the toad, bullfrog, guinea pig, rat, and cat. In all species studied, the total and "cellular" calcium content of the atrium were higher than those of the ventricle. A high calcium content of the atrial muscle was also observed in fresh unperfused hearts. The total calcium content of atrial and ventricular muscles increased when extracellular phosphate concentration was increased. When severe ventricular arrhythmia such as fibrillation occurred during perfusion, the total calcium content of the ventricle increased. The decay of tissue calcium content with calcium washout was examined in the toad, guinea pig, and rat heart. It was revealed that about 80 percent of total calcium existed as "exchangeable" calcium in both atrial and ventricular muscles. When the extracellular calcium concentration ([Ca]o) was altered in the toad, guinea pig, and rat heart preparation, the cellular calcium content of atrial muscle varied in proportion to [Ca]o, whereas that of ventricular muscle remained fairly constant at a higher [Ca]o value. The development of contractile tension in the atrial and ventricular muscles at various [Ca]o values corresponded well to these changes in the cellular calcium content except for the rat ventricle in which the contractile tension was almost proportional to [Ca]o. The relationship between the development of contractile tension and the level of cellular calcium content or [Ca]o was discussed.

The Calcium Concentration in Pancreatic Secretion in Chronic Pancreatitis and Carcinoma of the Pancreas

Warwick, R. R. G., Tothill, P., Percy-Robb, I. W. & Shearman, D. J. C. 1973. The Calcium Concentration in Pancreatic Secretion in Pancreatitis and Carcinoma of the Pancreas. Scand. J. Gaslroent. 8, 301-305.Calcium concentrations in the duodenal aspirate during a standard secretin stimulation test were measured in a series of 21 patients with a normal pancreas, 14 patients with pancreatitis and 7 patients with pancreatic carcinoma. A significant difference in calcium concentrations was found between the normal and the two abnormal groups, and it is suggested that this estimation may be a useful additional variable in the detection of pancreatic disease. When [47Ca] calcium chloride was injected intravenously [47Ca] appeared rapidly in the duodenal aspirate in normal subjects. In one patient with chronic pancreatitis there was some evidence of an increase in the pancreatic pool of calcium.

The distribution and exchange of brain calcium in vivo in the rat.

Calcium exhibits a heterogenous distribution among the various brain areas studied. The pituitary gland contains 25.97 meq./kg of wet tissue, followed by the pons containing 9.91 meq. and the hypothalamus 5.35 meq. The calcium content in the other areas is as follows: 4.23 meq. in medulla, 4.0 meq. in cerebral white matter, 3.60 meq. in cerebellum and about 3.0 meq./kg of wet tissue in the cerebral cortex. No difference in calcium concentration was found between the right and left corresponding brain areas. The distribution of brain calcium between the extracellular and cellular compartments was derived, and indicates that the concentration of cellular calcium is several-fold that in the extracellular space. Three hours after intraperitoneal injection of 47Ca Cl2, the maximum uptake of 47Ca was reached in all tissues except the pituitary gland where maximum uptake occurred 1 h after injection. The radioactive calcium in the brain was resolved into two components: A fast component having a short half time ranging between 0.5 and 4.25 h and a relatively slow component having a half time of 4.5–18 h. In the pituitary gland, pons, hypothalamus and medulla the calcium exchanges partially with serum calcium whereas, in cerebellum, cerebral cortex and white matter of cerebrum, tissue calcium is completely exchangeable.

Interaction of proteoglycans and chondroitin sulfates with calcium or phosphate ions.

Equilibrium dialysis was used to study the distribution of calcium or phosphate ions at equilibrium in dialysis cells containing proteoglycan or chondroitin sulfate in one compartment. A higher concentration of calcium or lower concentration of phosphate was found in the cell compartment containing the polymer than in the compartment separated from it by a semipermeable membrane. The difference in calcium concentration across the boundary represents bound calcium. The formation constant (K) for the complex of bound calcium with chondroitin sulfate was investigated and found to be affected by two main factors: ionic strength and calcium/glucuronate ratio. K decreased rapidly with increasing ionic strength up to 0.15. At low ionic strength and high Ca2+/glucuronate ratios, evidence has been obtained that more calcium is bound by the polymers than can be accounted for by the simple equilibrium system, involving the combination of one calcium per disaccharide unit period, whose operation is consistent with the K values found at low Ca/glucuronate ratios over a wide range of ionic strengths. Infrared spectra obtained at high and low Ca2+/glucuronate ratios also indicate the existence of two calcium forms of proteoglycans. Viscosity and ultracentrifugal data show that differences exist between proteoglycans in calcium and sodium solutions. The data for disaggregated proteoglycan preparations indicate that their calcium-binding properties are very similar to those of chondroitin 4-sulfate and are determined by the same factors. One aggregated puppy rib proteoglycan, however, showed significantly greater K values than chondroitin 4-sulfate; these decreased after disaggregation.

Normal Serum Calcium Levels by Atomic Absorption Spectroscopy

Abstract Normal adult calcium levels were established with the atomic absorption spectrophotometric technic of Zettner and Seligson (1). Significant differences in calcium concentration were shown to exist between the sexes. Three commonly employed serum treatment technics were compared; two gave equivalent results.

The effect of thyrocalcitonin on blood-bone calcium equilibrium in the perfused tibia of the cat.

1. In the isolated tibia of the cat, perfused with blood from its own carotid connected to popliteal artery via a pump, infusion of porcine thyrocalcitonin causes an arteriovenous difference in calcium concentration of up to 5%, corresponding to net retention of calcium in bone.2. When taken in conjunction with determinations of radiocalcium clearance in the tibia, the effect is of the right order of magnitude to account for the hypocalcaemic action of thyrocalcitonin in the whole animal.3. Calcium retention was accompanied by a small increase in acidity of outflowing venous blood whereas verification of the hypothesis of calcium regulation by pH change in the bone substance would require a decrease.

Physiological Studies on Fructification of Peanut : 8. On the relation between the calcium in the fruiting zone and the formation of unfilled fruit.

This report deals with the results obtained in the various peanuts relative to the evaluation of calcium movement from the vegetative tissue to the fruiting organs when the nutrient treatments which differential amounts of calcium were applied to the fruiting zone, to essential amounts of calcium in the fruiting zone required for fruit filling, and to the quantitative difference of fractional calcium in above treatments. The isolated methods as reported previously, were begun on the various peanuts, and the nutrient solutions which contained the following amounts of calcium were added at weekly intervals to the fruiting zone of 2.8 kg acid-washed sand throughout the experiment: distilled water, minus Ca, 20 mg. Ca, 40 mg. Ca, and 60 mg. Ca as the complete solution. Before the pegs had penetrated the sand of the fruiting zone, 0.3 mc. of radiocalcium was applied to the rooting zone of each plant. 1. It was found that in case of runner type the immature pods including the subterranean pegs were more numbered than the aerial pegs, and that in case of bunch types the aerial pegs were more numbered than the immature pods. So far as those varieties are concerned, the unfilled fruits were formated only on the plants of Virginia type, and bunch varieties of the same type were found to have a greater tolerance against the formation of unfilled fruit than the runner ones. The rate of calcium contents in the shell and seed of Spanish varieties was somewhat greater than that of Virginia and Valencia. 2. The levels of calcium amounts of the fruiting zone where the unfilled fruits were formated, were 20 and 0 mg per 2.8 kg sand for Chiba-74 (runner type) and Tachi-Rakkasai (bunch type), respectively. In Southern Cross (bunch type of small-seed), irrespective of the amounts of calcium in this zone there were not observed the yield of unfilled fruits. In general the differences in the concentration of calcium in the fruiting zone seemed to have greatly affected calcium contents of the shell in all varieties, except in Southern Cross. On the other hand, there were no considerable differences in calcium contents in the seed of the above samples, but the contents of Chiba-74 were apparently less than the other two bunch vatieties. When the calcium deficient treatments were given in the fruiting zone, the very active translocation of Ca45 was observed from the vegetative tissue into the shells and seeds of the above varieties, and the movement of the labeled calcium into the seed in the bunch varieties was found to be more active than in the runner one. With adequate calcium supplied in the fruiting zone, the shells and seeds of fully developed fruits contained very small amounts of labeled calcium. 3. In the shell, alcohol soluble calcium in the filled fruits of the bunch types did not show any difference in various calcium treatments of the fruiting zone, while on the other hand, that of the runner type seemed to have sensitively increased by the increasing supply of calcium in the fruiting zone. Additionally, there were high contents of calcium in the unfilled fruits, especially when they were due to the high concentration of calcium in the fruiting zone. Regardless of the various calcium levels of the fruiting zones, the shell was found to have almost the constant contents of acetic acid soluble calcium, excepting in the case of high calcium level in Southern Cross. The contents of HCl soluble calcium were increased by the increasing supply of calcium in the fruiting zone in any case, but in the minus calcium, it seemed to have the tendency that the shell having two unfilled seeds in the mature pod had lower contents of calcium than the ordinary shell. In the seed, each amount of alcohol soluble and acetic acid soluble calcium remained almost unchanged independently both of the increasing supply of calcium in the fruiting zone and of the types. [the rest omitted]