OBJECTIVETo explore the mechanism of cytotoxic effects of the organophosphates (OPs) with delayed neurotoxicity on human neuroblastoma cells.

METHODSThe proliferation of neuroblastoma SH-SY5Y cells was determined by MTT spectrometry. (45)Ca uptake was determined by adding (45)CaCl(2) and tri-o-cresyl phosphate (TOCP) or methamidophos into the cultured medium for the SH-SY5Y cells. The cells were incubated and then lysed and finally counted in a Beckman LS 6000 liquid scintillation spectrometer.

RESULTSMethamidophos stimulated the cell proliferation of SH-SY5Y at its lower concentrations (7 x 10(-7) mol/L to 7 x 10(-6) mol/L), with an increase by 28% at 7 x 10(-7) mol/L; however, it inhibited the proliferation at higher ones (7 x 10(-4) mol/L to 7 x 10(-3) mol/L) with 62% inhibition at 7 x 10(-3) mol/L. TOCP only inhibited the cell proliferation at high concentration (with 34% inhibition at 7 x 10(-3) mol/L) and markedly inhibited calcium uptake of the cells up to 55% at higher concentrations (1 x 10(-6) mol/L to 1 x 10(-4) mol/L); while the uptake was stimulated by OPs up to 241% of increase at lower concentrations (1 x 10(-9) mol/L to 1 x 10(-7) mol/L).

CONCLUSIONThe interference of growth in nerve cells and disturbance of calcium homeostasis may be involved in the mechanisms of neurotoxicity of OPs.

Calcium Radioisotopes ; metabolism ; pharmacokinetics ; Cell Division ; drug effects ; Cell Line, Tumor ; drug effects ; Humans ; Insecticides ; administration & dosage ; Neuroblastoma ; metabolism ; pathology ; Organophosphorus Compounds

AIMTo study the long-term effects of 17 beta-estradiol (E2) on cell proliferation, 45Ca up-take, and mineralized bone-like tissue formation in human osteoblast-like cell line TE85.

METHODSHuman osteoblast-like cell line TE85 was used as osteoblast cell model. Using methods of 3H-thymidine incorporation for cell proliferation and 45Ca deposit for calcium uptake, and Alizarin red S dye for mineralized bone-like tissue.

RESULTSCompared with the cells of control group, 3H-thymidine incorporation into TE85 cells was significantly increased (85.65%, 93.42% and 106.58%, respectively) and 45Ca uptake was increased (101.35%, 130.9% and 169.5% respectively), after treated with E2 (0.1, 1.0, 10 nmol.L-1) for 14 days. The stained area of Alizarin red S in E2 treated cells was also increased obviously. ICI182,780, a specific antagonist of estrogen receptor, was shown to partly inhibit E2 induced actions with the inhibition ratio of 19.6% or 37.28% in both experiments of 3H-TdR and 45Ca uptake on the condition of E2 (1.0 nmol.L-1).

CONCLUSIONE2 was found to increase the mineralized bone-like tissue by enhancement of cell proliferation and promotion of calcium uptake, which were in favor of bone formation. These actions may be partly mediated by estrogen receptor.

Bone Density ; Bone Neoplasms ; Calcium Radioisotopes ; metabolism ; Cell Division ; drug effects ; Estradiol ; pharmacology ; Humans ; Osteoblasts ; cytology ; drug effects ; Osteosarcoma ; Time ; Time Factors ; Tumor Cells, Cultured

UNLABELLEDTo study the effect of a Chinese herbal prescription on external calcium deposition to weight-bearing bone in simulated weightlessness rats.

METHODTwenty-one male Wistar rats were divided into 3 groups: control group, tail suspension group, tail suspension with Chinese medicine group which takes a Chinese herbal prescription extract (containing Radix Rehmanniae Preparata, Radix Acanthopanacis Bidentatae, Radix Astragali, Radix Angelicae Sinensis, Concha Ostreae prepared by acetic acid) by intragastric administration. After 1 week adaption, there start off 3 weeks simulated weightlessness by tail suspension. At the eleventh day of simulated weightlessness, every rat was given one equal dose of 41Ca tracer by intragastric administration. Right femurs were separated as experiment over, and the ratio of 41Ca to 40Ca (41Ca/40Ca) was measured by accelerator mass spectrometry (AMS), while total femur calcium was measured by inductively coupled plasma-atomic emission spectroscopy (ICP-AES). Femur 41Ca deposition amount (DA) and femur 41Ca deposition ratio (DR) were calculated.

RESULTThe results showed that compared with control group, 41Ca/40Ca decreased significantly (P < 0.001) in tail suspension group, while in tail suspension with Chinese medicine group, it significantly increased (P < 0.05). DA and DR were both decreased significantly (P < 0.001) in tail suspension group, but no significant change in tail suspension with Chinese medicine group as compared with control group. Compared with tail suspension group, DA and DR increased significantly (P < 0.001) in tail suspension with Chinese medicine group.

CONCLUSIONSimulated weightlessness by tail suspension can cause decreased deposition of external calcium to weight-bearing bone, and the Chinese herbal prescription in this trial is effective to prevent the decrease. Moreover, multiple mechanisms may contribute to weightlessness induced osteoporosis, besides calcium deposition disturbance.

Animals ; Bone Resorption ; etiology ; metabolism ; Calcification, Physiologic ; drug effects ; Calcium ; metabolism ; Calcium Radioisotopes ; Drugs, Chinese Herbal ; pharmacology ; therapeutic use ; Femur ; drug effects ; metabolism ; Hindlimb Suspension ; Male ; Mass Spectrometry ; Rats ; Rats, Wistar ; Weightlessness Simulation ; adverse effects

Ca45 resorption and incoporration into albino rat-bones in tissue culture was considered in studying the pathogenesis of osteoporosiscaused by cotinued administration of glucocorticoid, hydrocortisone succinate. 18-day old tibias were cultured in a chemically defined media, (BGJb). Hydrocotisone showed no effect on Ca45 resorption and little increase of Ca45 incorporation into bone. This may suggest that hydrocortisone produces osteoporosis not by direct effect but by secondary effects on calcium metabolism.
Animal ; Bone Development ; Bone and Bones/embryology ; Bone and Bones/metabolism* ; Calcification, Physiologic/drug effects ; Calcium/metabolism* ; Calcium Radioisotopes ; Hydrocortisone/adverse effects ; Hydrocortisone/pharmacology* ; Osteoporosis/chemically induced* ; Rats ; Tibia ; Tissue Culture

Glycerophosphrylocholine (GPC) is a renal medullary compatible organic osmolyte that is derived from choline via phosphatidylcholine, which is catalyzed in part by phospholipase A2 (PLA2) and its degradation by GPC: choline phosphodiesterase (GPC: choline PDE). We found that caffeine elevated intracellular free calcium ([Ca2+]i) and GPC level in cultured MDCK cells, canine kidney epithelial cells, and propose a possible biochemical mechanism. When MDCK cells were incubated for 3 h with 1 to 10 mM caffeine, cellular GPC was elevated in a dose-dependent manner, and this occurred independently of the extracellular osmolality. Caffeine stimulated the rate of [14C]choline incorporation into [14C]GPC and PLA2 activity. Whereas, GPC: choline PDE activity was accompanied by less of increase. These enzyme changes demonstrate the increased net synthesis of MDCK GPC. In order to identify what triggers the PLA2 activation, [Ca2+]i was measured by using a fluorescence dye, Fura-2. Caffeine (10 mM) resulted in a typical transient increase in MDCK [Ca2+]i concentration, and this increase was greatly inhibited by pretreatment of MDCK cells with 10 mM ryanodine for 5 min. Ryanodine (10 mM) also inhibited the caffeine-induced stimulation of PLA2 activity. These findings provide the first evidence that caffeine in MDCK cells causes a ryanodine-inhibitable increase of [Ca2+]i and PLA2 activity, resulting in cellular GPC accumulation.
Animal ; Caffeine/pharmacology* ; Calcium/metabolism* ; Carbon Radioisotopes ; Cell Line ; Choline/metabolism ; Dogs ; Glycerylphosphorylcholine/metabolism* ; Kidney/cytology ; Phospholipases A/metabolism* ; Phospholipases A/drug effects ; Phospholipases A/antagonists & inhibitors ; Phosphoric Diester Hydrolases/metabolism ; Phosphoric Diester Hydrolases/drug effects ; Ryanodine/pharmacology* ; Ryanodine/metabolism

This paper aims to present one of the rarest types of malignancies, parathyroid carcinoma. Parathyroid carcinoma is an important cause of primary hyper par athyroidism. Diagnostic evaluation of patients presenting with signs and symptoms of hyperparathyroidism consists of serum calcium and parathyroid hormone determination, parathyroid imaging using ultrasound, computed tomography, magnetic resonance imaging, or Tc-99m sestamibi scintigraphy, and histopathologic evaluation of tissues after surgical intervention. Therapeutic management of an identified parathyroid tumor is by parathyroidectomy during neck exploration or radioisotope-guided with the use of a gamma probe. The histology of a resected tumor determines if the initial surgery completes the management, or, in cases of parathyroid carcinoma, if another completion surgical intervention is to be made. This paper will present a patient who has been initially diagnosed with primary hyperparathyroidism and was referred to our nuclear medicine department for parathyroid scintigraphy. The patient underwent MIRP and rapid intraoperative PTH determination. Histopathologic report on the tissues revealed parathyroid carcinoma. The patient underwent a second surgery for definitive treatment. This paper will discuss the clinical role of nuclear medicine in the diagnosis and surgical management of parathyroid carcinoma.

Human ; Female ; Aged ; Calcium ; Hyperparathyroidism, Primary ; Magnetic Resonance Imaging ; Nuclear Medicine ; Parathyroid Glands ; Parathyroid Hormone ; Parathyroid Neoplasms ; Parathyroidectomy ; Radioisotopes ; Radionuclide Imaging ; Technetium Tc 99m Sestamibi ; Tomography ; Hypertension ; Kidney Calculi