Continuous nondestructive monitoring of intracellular ionized calcium in isolated squid axons by differential absorption spectroscopy (using arsenazo III and antipyrylazo III) was used to study uptake of calcium by carbonyl cyanide, p-trifluoromethoxy-phenylhydrazone (FCCP)- and (or) cyanide (CN)-sensitive and insensitive constituents of axoplasm. Known calcium loads imposed on the axon by stim...

A 79-year-old white man with a history of progressive bone pain was admitted for evaluation 3 years ago. The patient reported that the pain began in both feet and gradually spread to the rest of the body over a 2-year period. Further assessment revealed multiple stress fractures in the feet. Bone mineral density test indicated osteopenia. Serial bone mineral density tests during the 2 years sho...

It has been shown that an acute infusion of dipyridamole increased renal phosphate reabsorption in rats and humans. A prospective study was performed to determine whether chronic treatment by dipyridamole given orally could decrease renal phosphate leak and increase serum phosphorus in patients with idiopathic low renal phosphate threshold (TmPO4/GFR < 0.77 mM). Sixty-four patients with low TmP...

The solubility of triclinic calcium pyrophosphate dihydrate (CPPD) crystals was measured under varying conditions using 45Ca-labeled crystals, expressing solubility as micromoles per liter of 45Ca in solution. In a 0.1-M Tris-HC1 buffer pH 7.4, the solubility of accurately sized CPPD crystals (37-20mum) was 60muM with maximal solubility being attained after about 8 h incubation at 37degreeC. Re...

IN man and most mammals the concentration of calcium in the blood and body fluids remains almost constant under normal conditions, with only slight fluctuations. For the various cellular functions which are dependent on calcium, for example neuromuscular transmission, it is the ionized fraction of calcium (approximately 50 per cent of the total serum calcium level) which is important, and it is...

The skeleton contains approximately 98% of total body calcium. The remaining 2% circulate throughout the body. Calcium is regulated in the healthy mammalian body between approximately 2.20 and 2.60 mmol/L or 9-llmg/dl. A complex relationship exists between the gastrointestinal uptake of calcium, calcium clearance by the kidney and calcium translocation from the small pool in the serum to the la...

INTRODUCTION Calcium has anti-proliferative and pro-differentiation effects on cells in vitro and can inhibit the development of various cancers. While there is some epidemiologic evidence for an inverse relation between dietary calcium intake and prostate cancer risk, only few have focused on serum calcium levels in this respect. MATERIALS AND METHODS We assayed total serum calcium and ioniz...

We studied quantitative aspects of coronary artery contraction in isolated epicardial coronary ring segments from 49 human hearts. The order of maximal tension developed by drugs in normal calcium (ionized calcium, 1.26 mM) solution was U-44069 (a prostaglandin endoperoxide analog) greater than histamine greater than carbachol greater than serotonin greater than phenylephrine greater than ergon...

We have developed a new test for estimating the secretory capacity of parathyroid hormone (PTH) from the parathyroid gland. Sodium bicarbonate solution [8.4% (w/v); 35 ml/m(2) body surface area] was infused for 2 min, and blood samples for the determination of plasma ionized calcium, plasma PTH (intact, midregion, carboxy-terminus) and related parameters were serially obtained. In 8 healthy vol...