ABSTRACT
OBJECTIVE: In subjects with idiopathic calcium pyrophosphate dihydrate (CPPD) deposition disease, cartilage chondrocytes elaborate increased amounts of PPi. The mechanism of the intracellular PPi elevation is not known. Plasma membrane 5'-nucleotide phosphodiesterase I/nucleotide pyrophosphohydrolase (NTPPPH) activity also is elevated in chondrocytes and dermal fibroblasts of patients with idiopathic CPPD deposition disease. NTPPPH, as an ecto-enzyme, could act within certain intracellular compartments. Thus, we hypothesized a potential causal link between increased NTPPPH activity and increased intracellular PPi. METHODS: Transformed simian fibroblasts (COS cells) and human osteoblasts (U2OS cells) were transfected with the 5'-nucleotide phosphodiesterase I ecto-enzyme plasma cell membrane glycoprotein-1 (PC-1), recently shown to be expressed in cartilage, osteoblasts, and fibroblasts. RESULTS: Transfection with PC-1 markedly up-regulated 5'-nucleotode phosphodiesterase I activity and increased intracellular PPi concentrations by increasing the capacity of cells to generate PPi. Importantly, this did not require supplementation with exogenous nucleotides. CONCLUSION: Cellular overexpression of PC-1 produces NTPPPH overactivity and increased intracellular PPi generation in vitro. These findings support the potential importance of NTPPPH overactivity in PPi generation, both inside and outside the cell, in some subjects with CPPD deposition disease.
Subject(s)
Diphosphates/metabolism , Membrane Glycoproteins/pharmacology , Phosphoric Diester Hydrolases/metabolism , Pyrophosphatases/metabolism , Animals , Calcium Metabolism Disorders/enzymology , Calcium Metabolism Disorders/metabolism , Cells, Cultured , Fibroblasts/enzymology , Fibroblasts/metabolism , Haplorhini , Humans , Membrane Glycoproteins/biosynthesis , Osteoblasts/enzymology , Osteoblasts/metabolism , Phosphodiesterase I , Phosphoric Diester Hydrolases/drug effects , Pyrophosphatases/chemistry , Pyrophosphatases/drug effects , TransfectionABSTRACT
La CaMgATPasa es una enzima involucrada en los movimientos de calcio a través de las membranas biológicas. Nosotros testeamos la actividad de dicha enzima en membranas de eritrocitos de 17 pacientes hipercalciúricos y la comparamos con 8 controles sanos. Los pacientes con hipercalciuria tuvieron una actividad de CaMgATPasa que fue significativamente superior a los controles (18,02 2,83 vs 14,69 1,78 nM . mg-1 p<0,01). La excreción de urinaria de calcio en 24 hs (UCa.V) estuvo directa y significativamente relacionada con la actividad de la enzima (UCa.V: 36,31 x CaMgATPasa - 371,08 r:0,65 p<0,05) sólo en pacientes con hipercalciuria. Cuando agrupamos los pacientes acorde al diagnóstico fisiopatológico en hipercalciuria absortiva (HCA) e hipercalciuria renal (HCRT) encontramos que la actividad enzimática estuvo sólo significativamente elevada en aquellos portadores de HCA al compararlos con los controles (19,17 3,49 vs 14,68 1,79 nM . mg-1 .min-1 p<0,025).No encontramos diferencias estadísticamente significativas entre HCRT y controles (16,83 1,99nM . mg-1 . min-1; p:NS) y en HCRT vs HCA (p<0,14). Concluimos que las alteraciones en el transporte de calcio en la hipercalciuria dependería de anormalidades en la actividad de la CaMgATPasa
Subject(s)
Humans , Male , Female , Adult , Middle Aged , Erythrocyte Membrane/enzymology , Calcium/urine , Urinary Calculi/physiopathology , Calcium-Transporting ATPases/diagnosis , Ca(2+) Mg(2+)-ATPase/diagnosis , Calcium Metabolism Disorders/enzymology , Urinary Calculi/enzymology , Urinary Calculi/etiology , Calcium/physiology , Calcium/blood , Calcium Metabolism Disorders/classification , Calcium Metabolism Disorders/etiology , Calcium-Transporting ATPases/physiology , Calcium-Transporting ATPases/blood , Ca(2+) Mg(2+)-ATPase/physiologyABSTRACT
La CaMgATPasa es una enzima involucrada en los movimientos de calcio a través de las membranas biológicas. Nosotros testeamos la actividad de dicha enzima en membranas de eritrocitos de 17 pacientes hipercalciúricos y la comparamos con 8 controles sanos. Los pacientes con hipercalciuria tuvieron una actividad de CaMgATPasa que fue significativamente superior a los controles (18,02 2,83 vs 14,69 1,78 nM . mg-1 p<0,01). La excreción de urinaria de calcio en 24 hs (UCa.V) estuvo directa y significativamente relacionada con la actividad de la enzima (UCa.V: 36,31 x CaMgATPasa - 371,08 r:0,65 p<0,05) sólo en pacientes con hipercalciuria. Cuando agrupamos los pacientes acorde al diagnóstico fisiopatológico en hipercalciuria absortiva (HCA) e hipercalciuria renal (HCRT) encontramos que la actividad enzimática estuvo sólo significativamente elevada en aquellos portadores de HCA al compararlos con los controles (19,17 3,49 vs 14,68 1,79 nM . mg-1 .min-1 p<0,025).No encontramos diferencias estadísticamente significativas entre HCRT y controles (16,83 1,99nM . mg-1 . min-1; p:NS) y en HCRT vs HCA (p<0,14). Concluimos que las alteraciones en el transporte de calcio en la hipercalciuria dependería de anormalidades en la actividad de la CaMgATPasa
Subject(s)
Humans , Male , Female , Adult , Middle Aged , Erythrocyte Membrane/enzymology , Calcium/urine , Urinary Calculi/physiopathology , Calcium-Transporting ATPases/diagnosis , Ca(2+) Mg(2+)-ATPase/diagnosis , Calcium Metabolism Disorders/enzymology , Urinary Calculi/enzymology , Urinary Calculi/etiology , Calcium/physiology , Calcium/blood , Calcium Metabolism Disorders/classification , Calcium Metabolism Disorders/etiology , Calcium-Transporting ATPases/physiology , Calcium-Transporting ATPases/blood , Ca(2+) Mg(2+)-ATPase/physiologyABSTRACT
La CaMgATPasa es una enzima involucrada en los movimientos de calcio a través de las membranas biológicas. Nosotros testeamos la actividad de dicha enzima en membranas de eritrocitos de 17 pacientes hipercalciúricos y la comparamos con 8 controles sanos. Los pacientes con hipercalciuria tuvieron una actividad de CaMgATPasa que fue significativamente superior a los controles (18,02 2,83 vs 14,69 1,78 nM . mg-1 p<0,01). La excreción de urinaria de calcio en 24 hs (UCa.V) estuvo directa y significativamente relacionada con la actividad de la enzima (UCa.V: 36,31 x CaMgATPasa - 371,08 r:0,65 p<0,05) sólo en pacientes con hipercalciuria. Cuando agrupamos los pacientes acorde al diagnóstico fisiopatológico en hipercalciuria absortiva (HCA) e hipercalciuria renal (HCRT) encontramos que la actividad enzimática estuvo sólo significativamente elevada en aquellos portadores de HCA al compararlos con los controles (19,17 3,49 vs 14,68 1,79 nM . mg-1 .min-1 p<0,025).No encontramos diferencias estadísticamente significativas entre HCRT y controles (16,83 1,99nM . mg-1 . min-1; p:NS) y en HCRT vs HCA (p<0,14). Concluimos que las alteraciones en el transporte de calcio en la hipercalciuria dependería de anormalidades en la actividad de la CaMgATPasa
Subject(s)
Humans , Male , Female , Adult , Middle Aged , Calcium Metabolism Disorders/enzymology , Calcium/urine , Ca(2+) Mg(2+)-ATPase , Calcium-Transporting ATPases , Urinary Calculi/physiopathology , Erythrocyte Membrane/enzymology , Calcium Metabolism Disorders/classification , Calcium Metabolism Disorders/etiology , Calcium/physiology , Calcium/blood , Ca(2+) Mg(2+)-ATPase/physiology , Calcium-Transporting ATPases/physiology , Calcium-Transporting ATPases/blood , Urinary Calculi/enzymology , Urinary Calculi/etiologySubject(s)
Calcium Metabolism Disorders/enzymology , Calcium-Transporting ATPases/blood , Calcium/urine , Erythrocyte Membrane/enzymology , Kidney Calculi/enzymology , Adolescent , Adult , Biological Transport, Active , Calcium/metabolism , Calcium Metabolism Disorders/complications , Female , Humans , Kidney Calculi/complications , Male , Middle AgedABSTRACT
Synovial fluid adenosine triphosphate pyrophosphohydrolase, an enzyme which manifests increased activity in chondrocalcinosis and osteoarthritis, was partially characterized in synovial fluids from 41 patients who had a variety of arthropathies. Activity was found to be a soluble, heat labile, and divalent cation-dependent nonspecific nucleotide pyrophosphohydrolase with pH optimum 9.0-9.5.
Subject(s)
Adenosine Triphosphatases/analysis , Joint Diseases/enzymology , Pyrophosphatases , Synovial Fluid/enzymology , Adenosine Triphosphatases/antagonists & inhibitors , Arthritis, Rheumatoid/enzymology , Calcium Metabolism Disorders/enzymology , Chromatography, Ion Exchange , Gout/enzymology , Humans , Hydrogen-Ion Concentration , Joint Diseases/blood , Kinetics , Osteoarthritis/enzymology , Substrate Specificity , Uridine Diphosphate Glucose/metabolismABSTRACT
Studies were made to investigate the effect of food Mg level on ALAT, ASAT, LD and BASP values in pigs. The following conclusions were drawn:--a high food Mg level (0.31% in ordinary pig food) can cause an increase in serum BASP values.--leg weakness, at the primary stage, is hardly caused by disturbances in bone.--an ordinary diet low in Mg may cause an abnormal rise in ALAT values in pigs.--when feeding pigs on an ordinary diet, pigs may suffer from Mg deficiency despite the fact that the food Mg content is distinctly higher than that recommended by international norms for feeding.--a prompt lowering of food Mg level can cause a manifest increase in ASAT, LD and BASP values within 2 to 3 days in pigs. Heart and liver injuries caused by low Mg diets and the individual ability of pits to utilize magnesium were discussed.