Significant Increase In Calcium Research Articles

Intracellular calcium in primary cultures of rat renal inner medullary collecting duct cells during variations of extracellular osmolality.

There is ample evidence of calcium being an intracellular second messenger during volume regulatory processes in various cells including inner medullary collecting duct (IMCD) cells. Therefore, we measured intracellular calcium concentrations (Cai) under anisotonic conditions in primary cultures of IMCD cells using the Fura-2 technique. Basal steady-state calcium at 600 mosmol/l was found to be 110 +/- 4 nmol/l; n = 119. Exposure to hypotonic medium (300 mosmol/l, reduction of sucrose) resulted, within 1 min, in a strong increase in calcium to 563 +/- 87 nmol/l (n = 7; P < 0.01), followed by a decrease over 4-6 min to twice the initial values. The calcium increase was smaller (260 +/- 14 nmol/l; n = 5; P < 0.05) when the osmotic pressure was decreased by reducing NaCl instead of sucrose. Stepwise reduction of osmolarity to either 500 or 400 mosmol/l increased calcium by a significantly smaller extent, suggesting a threshold for calcium influx between 400 and 300 mosmol/l. In hypotonic calcium-free solutions no significant increase in calcium was observed. Verapamil (40 mumol/l), D-600 (40 mumol/l), diltiazem (40 mumol/l), and nifedipine (40 mumol/l) inhibited the hypotonically induced calcium influx in decreasing order of potency. Lanthanum (La3+) and gadolinium (Gd3+) had no effect. Membrane depolarization by incubation in potassium-rich solution diminished calcium influx. Preincubation with cytochalasin B (50 mumol/l for 30 min) resulted in a lower basal calcium level and attenuated the calcium increase during hypotonic shock. These results demonstrate an increased calcium influx during hypotonic shock in IMCD cells in culture mediated by channels whose nature (stretch activated and/or voltage dependent) remains to be determined. The transient increase in Cai in turn may trigger inorganic and organic osmolyte fluxes observed previously.

Plaque fluid pH, calcium and phosphorus responses to calcium food additives in a chewable candy

Fourteen subjects between 7 and 17 years of age with an equal distribution of low and high caries activity were given: (1) a 10% sucrose rinse, (2) a reference candy, (3) a reference candy with 3% dicalcium phosphate dihydrate, and (4) a reference candy with 0.75% calcium lactate on four different occasions. Plaque samples were collected before and at 15-min intervals after the sucrose rinse or food challenge for a period of 1 h on each occasion. Plaque samples were centrifuged and the extracellular plaque fluid analysed by a microtechnique for pH, total calcium and inorganic phosphorus concentration. There was no significant increase in calcium and phosphorus in plaque fluid for the group using candy with added calcium compared to the reference candy or sucrose rinse. There was no significant difference between the measurements in subjects grouped as caries active or inactive. The results suggest no benefit can be expected from adding dicalcium phosphate dihydrate and calcium lactate to candy to decrease demineralization during a cariogenic challenge.

Essential Elements in Dry and Canned Kidney Beans (Phaseolus vulgaris L.)

Ten essential mineral elements were determined in dry and in canned kidney beans (Phaseolus vulgaris L.). Samples were taken at different stages during the canning process to determine where changes in element content occurred. Canned kidney beans contained significantly lower concentrations of iron, magnesium, manganese, potassium, and zinc than dry kidney beans, on a dry weight basis. These decreases were probably caused by the elements being extracted out during soaking and blanching of the kidney beans and/or during the actual thermal processing where elements were extracted into the can liquid. There was a significant increase in calcium in the canned product and no significant difference in copper and phosphorus contents between the dry and canned products. Chloride and sodium content in canned kidney beans increased due to the sodium chloride content of the filling medium, and their concentrations varied depending on the concentration of the medium used. Retention of all elements, except chloride and sodium, ranged from 61 to 117% on a dry weight basis and from 19 to 36% on wet weight basis, retention being defined as the ratio of content in the canned to that in the dry product as received at the plant.

Diets realistic for westernised people significantly effect lipoproteins, calcium, zinc, vitamins C, E, B 6 and haematology in Vervet monkeys

This report describes measurements of 50 variables in adult, female, reproductively inactive Vervet monkeys during prolonged nutrition realistic for westernised people. Dietary treatments consisted of an atherogenic Western diet (WD) and a prudent Western diet (PD). Ingredients were normal foods for man and no extra cholesterol was added. Fortification of both diets with vitamin C after cooking was necessary to prevent deficiency. Randomised groups of Vervet monkeys received either the PD or WD for 47 months, while a third group was fed WD for 20 months and then PD for 27 months (WD-PD). Before the dietary treatments nourishment was by a high carbohydrate diet (HCD) and baseline and reference values (RV) apply to this nutritional status. Plasma total cholesterol (mg/dl) was increased from 147 (HCD) to 174 (PD) and 376 (WD). Individual cholesterolaemic response ranged from mild to severe and was stable (PD and WD). Dietary reversal (WD-PD) reduced cholesterolaemia promptly. Statistically significant increases in calcium, zinc and vitamin E and decreased vitamin B 6 were associated with the WD relative to the PD (in serum and plasma). Two cholesterol metabolising microsomal enzymes in liver were notably increased and one unchanged (WD). There were no dietary effects on triglycerides, vitamin A and glucose in plasma; insulin, glucagon, electrolytes, copper, magnesium or enzymes reflecting liver, muscle or brain cell damage in serum. Red blood cells, platelets and directly associated parameters increased (WD), haemoglobin was the same and haemoglobin per red cell decreased. Bleeding time was not affected. Bivariate correlations across the diets confirmed that Western nutrition promoted inherent individual susceptibility to cholesterolaemia. There were notable differences from RVs in total cholesterol, calcium, packed cell volume and haemoglobin, which emphasise excesses and deficiencies of the WD and PD.

The chronically pilocarpine-treated rat in the study of cystic fibrosis: Investigation on submandibular gland and pancreas

The chronically pilocarpine-treated rat has been proposed as an animal model for the disease cystic fibrosis, a generalized exocrinopathy. The effect of chronic pilocarpine treatment on structure, composition, and function of the acinar cells of rat submandibular gland and pancreas was investigated by electron microscopy, X-ray microanalysis, and biochemical analysis. The morphological effects of chronic pilocarpine treatment were most pronounced in the pancreas. The number and size of the zymogen granules was increased, and the granules had a less electron-dense appearance. X-ray microanalysis at the cellular level showed in both the submandibular gland and the pancreas a significant increase in calcium and a decrease in sodium. The increase in cellular calcium concentrations can be explained by an increase in the relative volume of secretory material in the cell (assessed by morphometry) and an increase in the local calcium concentration in the secretory material (assessed by X-ray microanalysis at the subcellular level). Chronic pilocarpine treatment caused a disturbance of glycolysis and energy metabolism in the submandibular gland, but no significant effects in this respect were noted in the pancreas. On the other hand, a nearly twofold increase of the pancreatic amylase activity was noted. The pancreas appeared somewhat hyperreactive towards cholinergic stimulation.

Vitamin D metabolism in pregnant rabbits: differences between the maternal and fetal response to administration of large amounts of vitamin D3.

Maternal and fetal metabolism of vitamin D was examined in term pregnant rabbits fed a normal diet and in those supplemented with a large amount of vitamin D3. Term pregnant rabbits (27--30 days of gestation) fed the normal diet showed lower levels of plasma calcium, 25-hydroxyvitamin D3 (250HD3), and 24,25-dihydroxyvitamin D3 [24,25-(OH)2D3] and higher plasma 1 alpha, 25-dihydroxyvitamin D3 [1 alpha, 25-(OH)2D3] levels than age-matched nonpregnant female rabbits. Kidney homogenates from pregnant rabbits produced mainly 1 alpha 25-(OH)2D3, while those from nonpregnant animals produced 24,25-(OH)2D3 primarily. Plasma concentrations of calcium and phosphorus were significantly higher in fetuses than in mothers. Plasma levels of 250HD3 and 24,25-(OH)2D3 in fetuses were almost identical to those in mothers, whereas 1 alpha,25-(OH)2D3 levels in plasma were significantly higher in mothers than in their fetuses. A daily administration of 650 nmol vitamin D3 for 3 days to term pregnant rabbits caused a significant increase in calcium, phosphorus, 25OHD3, and 24,25-(OH)2D3 in maternal plasma, and in 25OHD3 and 24,25-(OH)2D3, but not calcium and phosphorus in fetal plasma. Treatment with large amounts of vitamin D3 also induced a marked suppression of 1 alpha-hydroxylase activity and a concomitant increase of 24-hydroxylase activity in the maternal but not in the fetal kidney. Plasma concentrations of 1 alpha,25-(OH)2D3 were not affected by treatment with large amounts of vitamin D3 in either the fetuses or the mothers. These results clearly indicate that the renal 25OHD3 metabolism in the fetus is regulated independently of that in the mother.

Ground-Water Pollution by Septic Tank Drainfields

Analytical results from 386 ground-water samples were used to determine the effect of septic drainfield leaching on ground-water quality. The calcium carbonate type groundwater showed lower correlation coefficients between its main parameters in unsewered areas than in sewered areas. The negative correlation between calcium and sodium, the significant increase of calcium with time and with decreasing well depth points to a cation exchange in which sodium from sewage effluent is exchanged by calcium. The increase of calcium, chloride and nitrate with time was most significant in unsewered areas served by septic tanks. Highest nitrate and coliform concentrations were noted in the winter during maximum infiltration.

Microanalysis and X-ray fluorescence spectrometry of platelets in diseases with elevated muscle calcium.

Electron microscopic X-ray microanalysis and X-ray fluorescence spectrometry were done on platelets from patients with Duchenne muscular dystrophy and idiopathic scoliosis (both these conditions are known to be associated with increased intramyofibre calcium). A significant increase in calcium and phosphorus concentrations was found in the dense granules and whole cells of both conditions. The findings suggest that idiopathic scoliosis like Duchenne muscular dystrophy is a multisystem disease with detectable changes in platelets.

Collagenase Activity and Morphological and Chemical Bone Resorption Induced by Prostaglandin E2 in Tissue Culture

SummaryThe isolation of collagenase present in serum-containing medium harvested from bone cultures was effected by heparin-Sepharose affinity chromatography. Almost all of the bone tissue collagenase released into the medium was of the latent, inactive type, which could be activated in vitro with trypsin. Over the course of the experiment a 20-fold greater amount of collagenase was released into the medium by the resorbing cultures stimulated with prostaglandin E2 as compared to the control cultures. A significant increase in calcium released into the medium correlated in time with rapid bone resorption as measured microscopically. The increase in collagenase activity did not demonstrate the same precise time course.

Effect of Limestone Variables on Amendment of Acid Soils and Production of Corn and Coastal Bermudagrass

AbstractThree particle size ranges of calcitic and dolomitic limestones were applied at 4.5, 9, and 13.5 metric tons/ha. Evaluations were designed to determine the most efficient treatment for neutralizing soil acidity, and increasing crop production in Katy fine sandy loam (pH 5.2) and Boy loamy fine sand (pH 5.4). Liming effects were evaluated by soil and plant analyses. Efficiency rating (ER) was used to describe the limestone particle size ranges. Finer limestone particles were assigned higher relative efficiency values. The sum of the products of particle size percentage ranges multiplied by the relative efficiency assigned those ranges, times the neutralizing value of that limestone is the ER.Increases in soil pH were proportional to limestone ER and application rate. Calcitic limestone neutralized soil acidity more rapidly than did dolomitic. We found a statistically significant increase in calcium (Ca) in the 30‐ to 46‐cm depth of Boy loamy fine sand at the 13.5 metric ton/ha rate of ER 110 calcitic limestone. This was probably due to 689 kg of N/ha applied as NH4NO3 the first year following limestone treatment. Magnesium (Mg) increased in the 30‐ to 46‐cm depth due to all dolomitic treatments.Limestone did not increase the yield of corn (Zea mays L.) or Coastal bermudagrass (Cynodon Dactylon L. Pers.) in the harvest year.All treatments of calcitic limestone significantly increased the Ca percentage in corn. All dolomitic limestone treatments except the ER 26 material applied at 4.5 metric tons/ha increased Mg concentration in corn leaves and Coastal bermuda‐grass. Manganese toxicity occurred in corn plants growing in nonlimed plots the third season following treatment. Soil acidity and reducing conditions contributed to the toxicity.

The Hypermineralization of Diseased Root Surfaces,

Root surfaces which have lost their attachment due to chronic inflammatory periodontal disease present significant increases in calcium, magnesium, phosphorus, and fluoride. The clinical significance of this effect is not known in regards to wound healing, but it may be helpful in control of cervical sensitivity.

Changes in the Plasma Content of Calcium, Phosphorus, and Yolk Lipophosphoprotein Precursor during the Production Season in Turkeys

The plasma concentration of a lipophosphoprotein complex (LPP) averaged higher in nonbroody hens from a line selected for increased egg production (E) than in nonbroody hens from three growth strains of turkeys. The total plasma pool of LPP averaged higher in the growth lines. The concentration and total amount of LPP significantly declined during the 180-day production period in all lines. Plasma total calcium and total phosphorus concentrations increased greatly with the onset of egg production. Further significant increases in calcium (P<.05) and phosphorus (P<.01) concentrations were observed in medium-bodied hens after approximately three months of production. Plasma total calcium concentration declined (P<.01) in all lines during the last three months of the laying period.Number of broody periods from 0 to 84 days in production and effective length of the laying period were negatively correlated (P<.05) with initial (prior to stimulatory lighting) total phosphorus concentration in medium-bodied hens. Initial total calcium concentration was positively correlated (P<.05) with total days lost from broodiness for the total production period (0–180 days) and negatively correlated (P<.05) with effective length of the laying period in large-bodied hens. All correlation coefficients were small, however (less than .30).

Localised concentrations of elements in hamster cardiomyopathy

Localized elemental concentrations of Ca, P, Cl, S, and Zn were detected by X-ray microanalysis during viewing of ultrathin myocardial sections. Cardiomyopathic hamsters were compared with a healthy strain of the same age. Significant increases in calcium and chlorine concentrations were found in sick animals. These were highest in the hypertrophic stage of the disease. Phosphorus and zinc were more variable. Ratios between elements (especially P/Ca) in the same cells and of the same elements in different cell types were found to offer numerical criteria for estimating the degree of pathological change.