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PubMed1989

The relation between orthophosphate and pyrophosphate in normal subjects and in patients with urolithiasis.

In calcium lithiasis, inhibitors have a significant effect in reducing the crystallization process. This work evaluated orthophosphate in a group of patients with calcium oxalate lithiasis, and in a control group. The study of orthophosphate and pyrophosphate, showed differences between stone formers and the control group. These results could be attributed to a failure in the renal transformation of orthophosphate into pyrophosphate.

Diphosphates↗
PubMed1980

Modifying effect of commercially available stannous pyrophosphate (PYRO-Sn) on the tissue affinity of 99mTc pertechnetate.

Investigations were performed to examine the conditions required for in vivo labelling of red blood cells (RBCs) with 99mTc after injection of stannous pyrophosphate. It was found that good in vivo labelling of RBCs is possible and that the efficacy of this procedure is high. The highest concentration of 99mTc in the blood occurred in the first 2 h after pertechnetate injection, and the optimum time between stannous pyrophosphate and pertechnetate injection ranged from 10 to 30 min.

Animals↗
PubMed1986

Inhibition of calcium oxalate monohydrate (COM) crystal growth by pyrophosphate, citrate and rat urine.

An assay system for the measurement of the rate of Calcium Oxalate Monohydrate (COM) seed crystal growth in a metastable solution of calcium chloride and sodium oxalate containing traces of 14C-oxalic acid was used to assess the inhibitory activity of pyrophosphate (10(-5) M-10(-4) M), citrate (10(-4) M-10(-3) M) and urines of normal and pyridoxine deficient rats. Both pyrophosphate and citrate were strong inhibitors of COM crystal growth and caused a 50% decrease in crystal growth rate at 1.50 X 10(-5) M and 2.85 X 10(-4) M respectively. Normal rat urine strongly inhibited the COM crystal growth, while pyridoxine deficient animals showed a significant (p less than 0.01) decrease in mean inhibitory activity as compared to pair-fed controls. A lowered urinary inhibitory potential accompanied with hyperoxaluria and hypercalciuria, which is known to be associated with pyridoxine deficiency, may be a contributory risk of calcium oxalate crystallization and stone formation.

Animals↗
PubMed1986

The effects of glycosaminoglycans, pyrophosphate and allopurinol treatment on urease-induced crystallization in vitro.

Previous studies have found that human urine inhibits urease-induced crystallization in synthetic urine. To identify the inhibitory components the effects of chondroitin sulphate, heparin and pyrophosphate on urease-induced crystallization were studied and the inhibitory capacity of human urine collected during and before/after allopurinol treatment compared. None of the substances studied nor allopurinol treatment was found to influence the urease-induced crystallization. These findings do not support the idea that glycosaminoglycans or pyrophosphate are responsible for the inhibitory effect detected in human urine.

Allopurinol↗
PubMed1993

Mapping of multiple mouse loci related to the farnesyl pyrophosphate synthetase gene.

The prenyltransferases are a class of enzymes involved in the synthesis of sterol and nonsterol isoprene compounds. We report here the chromosomal mapping of nine loci in the mouse that hybridize to the cDNA for the enzyme farnesyl pyrophosphate synthetase (FPS), a prenyltransferase that catalyzes the synthesis of an intermediate common to both the sterol and nonsterol branches of the isoprene biosynthetic pathway. Mapping was performed with genomic DNA from a mouse-hamster somatic cell hybrid panel, and by linkage analysis with recombinant inbred strains and the progeny of an interspecific backcross. The mapped loci have been designated farnesyl pyrophosphate synthetase-like-1 (Fpsl-1) on mouse Chromosome (Chr) 3; Fpsl-2 on Chr 4; Fpsl-3, Fpsl-4, and Fpsl-5, dispersed on Chr 10; Fpsl-6 on Chr 12; Fpsl-7 on Chr 13; Fpsl-8 on Chr 17; and Fpsl-9 on Chr X. It is presently unclear which of these loci encode active prenyltransferases and which may correspond to pseudogenes. The strongly hybridizing loci provide convenient genetic markers for seven mouse chromosomes.

Animals↗
PubMed1983

Failure in labelling of red blood cells with 99mTc: interaction between intravenous cannulae and stannous pyrophosphate.

The effect of different methods of stannous pyrophosphate (SnPYP) administration on a modified in vivo technique for labelling red blood cells (RBCs) with 99mTc has been studied. Retention of 99mTc in the bloodstream was measured and parallel in vitro RBC labelling experiments were performed. After administration of SnPYP or a mixture of SnPYP and heparin via the metal needles of intravenous cannulae, the mean 30-min retentions of 99mTc were 96.8% (SD 8.6) and 95.3% (SD 12.4) respectively and the mean in vitro labelling efficiencies were 86.9% (SD 5.0) and 81.9% (SD 18.2) respectively. When the SnPYP was administered via teflon cannulae, the mean 30-min retention of 99mTc was 40.0% (SD 16.7) and the in vitro labelling efficiency was 18.7% (SD 27.0). Reduced RBC labelling and rapid clearance of 99mTc from the bloodstream were not explained by adsorption of stannous ion or pyrophosphate onto the teflon cannulae or retention of SnPYP in the cannulae. When labelling RBCs with 99mTc it is important that SnPYP is not injected via a teflon cannula.

Erythrocytes↗
PubMed1980

Effects of pyrophosphate and diphosphonates on the dissolution of hydroxyapatites using a flow system.

Pyrophosphate and diphosphonate ions have been said to diminish the dissolution of hydroxyapatite crystals, because they lower the equilibrium concentrations of calcium and phosphate ions in the bulk solution around hydroxyapatite crystals in a closed system. However, in a closed system these effects are not necessarily due to an effect on dissolution alone. In this paper we have used a continuous flow system to study the effects of pyrophosphate and two diphosphonates, ethane-1-hydroxy-1,1,-diphosphonate and dichloromethane diphosphonate, on the dissolution of hydroxyapatite. All three compounds decreased markedly the rate of dissolution of hydroxyapatite as well as the exchangeable pools of calcium and phosphate ions around the crystals.

Calcium↗
PubMed2003

[Calcium pyrophosphate dihydrate deposition disease].

Calcium pyrophosphate dihydrate deposition disease (CPPD) of the temporomandibular joint is rare. The disorder is characterized by the presence of crystal deposits within the affected joint. The deposition of crystals in adjacent soft tissue may lead to the formation of pseudotumors. This form of the disease is called tophaceous pseudogout and typically affects the temporomandibular joint. It is difficult to differentiate the disease, particularly from malignant tumors, on the clinical and radiographic findings alone. The diagnosis is based on histological identification of the calcium pyrophosphate crystals. We present an unusually advanced case of tophaceous pseudogout of the temporomandibular joint. The etiology, clinical and diagnostic criteria as well as treatment options are discussed on the basis of our own experience and a review of the literature.

Aged↗
PubMed2001

Physiological relevance of fructose 2,6-bisphosphate in the regulation of spinach leaf pyrophosphate:fructose 6-phosphate 1-phosphotransferase.

A major problem in defining the physiological role of pyrophosphate:fructose 6-phosphate 1-phosphotransferase (PFP, EC 2.7.1.90) is the 1,000-fold discrepancy between the apparent affinity of PFP for its activator, fructose 2,6-bisphosphate (Fru-2,6-P2), determined under optimum conditions in vitro and the estimated concentration of this signal metabolite in vivo. The aim of this study was to investigate the combined influence of metabolic intermediates and inorganic phosphate (Pi) on the activation of PFP by Fru-2,6-P2. The enzyme was purified to near-homogeneity from leaves of spinach (Spinacia oleracea L.). Under optimal in vitro assay conditions, the activation constant (Ka) of spinach leaf PFP for Fru-2,6-P2 in the glycolytic direction was 15.8 nM. However, in the presence of physiological concentrations of fructose 6-phosphate, inorganic pyrophosphate (PPi), 3-phosphoglycerate (3PGA), phosphoenolpyruvate (PEP), ATP and Pi the Ka of spinach leaf PFP for Fru-2,6-P2 was up to 2000-fold greater than that measured in the optimised assay and Vmax decreased by up to 62%. Similar effects were observed with PFP purified from potato (Solanum tuberosum L.) tubers. Cytosolic metabolites and Pi also influenced the response of PFP to activation by its substrate fructose 1,6-bisphosphate (Fru-1,6-P2). When assayed under optimum conditions in the gluconeogenic direction, the Ka of spinach leaf PFP for Fru-1,6-P2 was approximately 50 microM. Physiological concentrations of PPi, 3PGA, PEP, ATP and Pi increased Ka up to 25-fold, and decreased Vmax by over 65%. From these results it was concluded that physiological concentrations of metabolites and Pi increase the Ka of PFP for Fru-2,6-P2 to values approaching the concentration of the activator in vivo. Hence, measured changes in cytosolic Fru-2,6-P2 levels could appreciably alter the activation state of PFP in vivo. Moreover, the same levels of metabolites increase the Ka of PFP for Fru-1,6-P2 to an extent that activation of PFP by this compound is unlikely to be physiologically relevant.

Buffers↗
PubMed2001

[Calcium pyrophosphate arthropathy (pseudogout) of the temporomandibular joint].

The temporomandibular joint is rarely affected by crystal deposition disease (gout and pseudogout). Only the temporomandibular joint was affected in a 69-year-old patient with calcium pyrophosphate dihydrate deposition disease (pseudogout). This case is described here. Clinically presenting as painless swelling, computed tomography and magnetic resonance imaging showed signs of a chronic destructive arthritis. The evidence for calcium pyrophosphate dihydrate crystals was provided by histological examination. Diagnostic criteria, differential diagnosis and possibilities for treatment are discussed on the basis of our own experience and the literature.

Aged↗
PubMed2005

Inhibition of family II pyrophosphatases by analogs of pyrophosphate and phosphate.

Imidodiphosphate (the pyrophosphate analog containing a nitrogen atom in the bridge position instead of oxygen) is a potent inhibitor of family II pyrophosphatases from Streptococcus mutans and Streptococcus gordonii (inhibition constant Ki approximately 10 microM), which is slowly hydrolyzed by these enzymes with a catalytic constant of approximately 1 min(-1). Diphosphonates with different substituents at the bridge carbon atom are much less effective (Ki = 1-6 mM). The value of Ki for sulfate (a phosphate analog) is only 12 mM. The inhibitory effect of the pyrophosphate analogs exhibits only a weak dependence on the nature of the metal ion (Mn, Mg, or Co) bound in the active site.

Cobalt↗
PubMed2005

Complementary function of gamma delta T-lymphocytes and dendritic cells in the response to isopentenyl-pyrophosphate and lipopolysaccharide antigens.

Dendritic cells and gamma delta T-lymphocytes play a crucial role in the early response to microbial infections. Since both dendritic cells and gamma delta T-lymphocytes may be activated by specific microbial products, we analyzed their interplay in the presence of such respective ligands: lipopolysaccharide and isopentenyl-pyrophosphate. Activated gamma delta T-cells increased the maturational state of dendritic cells induced by lipopolysaccharide, increasing the expression of co-stimulatory and MHC class I and II molecules. IL-12 production by dendritic cells was strongly amplified in the presence of activated gamma delta T-cells and the Th1 polarization of naïve CD4(+) T-lymphocytes was significantly increased. On the other hand, dendritic cells enhanced gamma delta T-cell functions induced by isopentenyl-pyrophosphate and promote their IL-2 independent proliferation through CD86 contact. Altogether, dendritic cells and gamma delta T-cells exert a complementary function promoting an optimal immune response to non peptidic microbial antigens.

Antigens, CD↗
PubMed2006

Subcellular pyrophosphate metabolism in developing tubers of potato (Solanum tuberosum).

PPi has previously been implicated specifically in the co-ordination of the sucrose-starch transition and in the broader context of its role as co-factor in heterotrophic plant metabolism. In order to assess the compartmentation of pyrophosphate (PPi) metabolism in the potato tuber we analysed the effect of expressing a bacterial pyrophosphatase in the amyloplast of wild type tubers or in the cytosol or amyloplast of invertase-expressing tubers. The second and third approaches were adopted since we have previously characterized the invertase expressing lines to both exhibit highly altered sucrose metabolism and to contain elevated levels of PPi (Farré et al. (2000a) Plant Physiol 123:681) and therefore this background rendered questions concerning the level of communication between the plastidic and cytosolic pyrophosphate pools relatively facile. In this study we observed that the increase in PPi in the invertase expressing lines was mainly confined to the cytosol. Accordingly, the expression of a bacterial pyrophosphatase in the plastid of either wild type or invertase-expressing tubers did not lead to a decrease in total PPi content. However, the expression of the heterologous pyrophosphatase in the cytosol of cytosolic invertase-expressing tubers led to strong metabolic changes. These results are discussed both with respect to our previous hypotheses and to current models of the compartmentation of potato tuber metabolism.

Bacterial Proteins↗
PubMed2004

Calcium pyrophosphate dihydrate and basic calcium phosphate crystal-induced arthropathies: update on pathogenesis, clinical features, and therapy.

Calcium-containing crystals are the most common class for the osteoarthritic joint. They are responsible for acute periarthritis and destructive arthropathies, and for tissue deposits mimicking tumor-like masses. These crystals encompassed mainly calcium pyrophosphate dihydrate and basic calcium phosphate crystals, with the latter being related to hydroxyapatite, carbonate-substituted apatite, and octacalcium phosphate. Calcification deposit mechanisms will be reviewed with respect to extracellular inorganic pyrophosphate dysregulation mainly caused by modulation of specific membrane channel disorders. Genetic defects have been extensively studied and identified mutation of specific genes such as ANKH and COL. Pathogenesis of crystal-induced inflammation is related to synovial tissue and direct cartilage activation. Besides classical knee or wrist pseudogout attacks or Milwaukee shoulder arthropathies, clinicians should be aware of other specific common presentations, such as erosive calcifications, spinal cord compression by intraspinal masses, ligamentum flavum calcification, or atypical calcified tophus. Promising clinical results for preventing calcium crystal deposits and cartilage degradation are lacking. Practical imaging tools are needed to monitor reduction of calcification of fibrocartilage and articular cartilage as markers of drug efficacy.

Arthritis↗
PubMed1977

Technetium-99m pyrophosphate myocardial uptake in patients with stable angina pectoris.

99m-technetium (Tc) pyrophosphate myocardial scintigrams of 55 patients with stable angina pectoris were compared with those of 13 normal subjects. The mean scintigraphic score, obtained by averaging the blinded interpretations of four readers scoring on an integral scale from 0 to 4, was significantly higher for the patients with angina than for the control subjects (1.36 compared with 0.48, P less than 0.001). Among the patients with angina, those who had a prior myocardial infarction had a higher mean scintigraphic grade than those without a previous infarction (1.73 versus 1.15, P less than 0.005), and the mean grade in both groups was higher than that of control subjects (P less than 0.001). Radionuclide uptake was predominantly diffuse in the patients with angina pectoris (70%), although in those with greater uptake accumulation tended to be localized. Three of the 68 subjects had high levels of radionuclide uptake but no clinical evidence of acute myocardial injury. This study demonstrates that excess myocardial accumulation of 99m-Tc pyrophosphate can occur in patients with stable angina pectoris.

Angina Pectoris↗
PubMed1979

Doughnut pattern of technetium-99m pyrophosphate myocardial uptake in patients with acute myocardial infarction: a sign of poor long-term prognosis.

Thirty survivors of acute myocardial infarction with 3+ or 4+ positive technetium-99m pyrophosphate myocardial scintigrams were followed up for 28 +/- 3.1 months (mean +/- standard deviation). Three patient groups were identified from the pattern of radioactive uptake in the scintigram: Group I, 16 patients with focal uptake (anterior in 7, lateral in 2, posterior in 3 and inferior in 4); Group II, 6 patients with anterior myocardial infarction and a doughnut pattern of uptake; Group III, 8 patients with nontransmural myocardial infarction and a diffuse pattern of uptake. Late complications developed in all patients with the doughnut pattern of uptake compared with 43 percent of patients with the focal pattern and 12 percent of patients with the diffuse pattern. After discharge from the hospital, five of six patients with a doughnut pattern of uptake died (mean survival time 9.8 months after the initial myocardial infarction). This mortality rate (83 percent) was significantly greater than that of patients with a focal (mortality rate 6 percent) or diffuse (no mortality) pattern of uptake. The doughnut pattern of technetium-99m pyrophosphate myocardial uptake in patients with acute myocardial infarction appears to identify a subgroup of patients with a very poor long-term prognosis.

Angina Pectoris↗
PubMed1979

Prognostic value of a persistently positive technetium-99m stannous pyrophosphate myocardial scintigram after myocardial infarction.

Technetium-99m stannous pyrophosphate myocardial scintigrams were obtained in 138 clinically stable patients 32.7 +/- 47.3 weeks (range 6 to 260) after acute myocardial infarction. Of the 138 patients, 74 (54 percent) had a persistently positive scintigram. Patients with such a scintigram were more likely to have severe angina pectoris, compensated congestive heart failure, anterior location of acute myocardial infarction, Q waves and S-T segment elevation in the electrocardiograms, cardiomegaly, left ventricular dyssynergy (dyskinesia or global dyssynergy), and an ejection fraction of less than 50 percent. During a follow-up period of 11.6 +/- 6.9 months after scintigraphy, 42 percent of the patients with a persistently positive scintigram had either a cardiac death, a nonfatal myocardial infarction, unstable angina pectoris or decompensated congestive heart failure compared with 13 percent of the patients with a negative scintigram (P less than 0.001). Of the 14 patients with cardiac death, 13 (93 percent) had a persistently positive scintigram. A persistently positive scintigram not only was the best single predictor of cardiac death and combined end points, but also added significantly to the predictive ability of the other clinical variables, including age, location of acute myocardial infarct, clinical status, electrocardiographic findings, and chest X-ray findings. It is concluded that technetium-99m stannous pyrophosphate myocardial scintigraphy has prognostic value in patients after acute myocardial infarction.

Adult↗
PubMed1992

Riboflavin 5'-pyrophosphate: a contaminant of commercial FAD, a coenzyme for FAD-dependent oxidases, and an inhibitor of FAD synthetase.

Commercially available preparations of flavin adenine dinucleotide (FAD) have been found to be 94% pure, the remaining 6% being composed of four or five minor contaminants which can be separated from FAD by reverse-phase high-performance liquid chromatography. FAD purified in this manner has been shown to be 100% pure. One of the contaminants has been identified as riboflavin 5'-pyrophosphate (RPP) by spectroscopic and chemical methods of analysis. This compound has been shown to exhibit biological activity as a weak cofactor for two FAD-requiring enzymes. With the apoprotein of porcine D-amino-acid oxidase, values determined for RPP were 8.4 microM for Km and 0.10 for Vmax compared to 0.47 microM and 0.28 (36 U/mg), respectively, for FAD. With fungal glucose apooxidase, values determined for RPP were 474 nM for Km and 0.02 for Vmax and 45 nM and 0.09 (105 U/mg), respectively, for FAD. RPP can also inhibit FAD biosynthesis. For bovine liver FAD synthetase, a Ki value for RPP against FMN was determined to be 9 microM where Km for FMN was 5.5 microM. These studies illustrate the value of riboflavin 5'-pyrophosphate as a flavin analog for use in the study of structure/function relationships within certain flavin-dependent enzymes.

Animals↗