Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “PYROPHOSPHATES”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,675 records · Page 93Linked to original sources
PubMed2004

Improving the pyrophosphate-inosine phosphotransferase activity of Escherichia blattae acid phosphatase by sequential site-directed mutagenesis.

Escherichia blattae acid phosphatase/phosphotransferase (EB-AP/PTase) exhibits C-5'-position selective pyrophosphate-nucleoside phosphotransferase activity in addition to its intrinsic phosphatase. Improvement of its phosphotransferase activity was investigated by sequential site-directed mutagenesis. By comparing the primary structures of higher 5'-inosinic acid (5'-IMP) productivity and lower 5'-IMP productivity acid phosphatase/phosphotransferase, candidate residues of substitution were selected. Then a total of 11 amino acid substitutions were made with sequential substitutions. As the number of substituted amino acid residues increased, the 5'-IMP productivity of the mutant enzyme increased, and the activity of the 11 mutant phosphotransferases of EB-AP/PTase reached the same level as that of Morganella morganii AP/PTase. This result shows that Leu63, Ala65, Glu66, Asn69, Ser71, Asp116, Thr135, and Glu136, whose relevance was not directly established by structural analysis alone, also plays an important role in the phosphotransferase activity of EB-AP/PTase.

Acid Phosphatase↗
PubMed1982

Inactivation and reactivation of rat liver 3-hydroxy-3-methylglutaryl-CoA-reductase phosphatases: effect of phosphate, pyrophosphate and divalent cations.

Incubation of four purified rat liver HMG-CoA-reductase phosphatases (Gil, G., Sitges, M. and Hegardt, F.G. (1981) Biochim. Biophys. Acta 663, 211-221) with Mn2 or Mg2 caused a concentration-dependent activation of enzyme activities. The maximum effect for Mn2 was at 5 mM for all phosphatases. Fe2 caused inactivation only in reductase phosphatases IIa and IIb. Ca2 10 mM showed a slight effect of inactivation. Phosphate, pyrophosphate and adenine nucleotides inhibited the four reductase phosphatases, this process being concentration-dependent. cAMP did not inhibit the four phosphatases at all in the range of 0.01-8 mM. Preincubation of reductase phosphatases with PPi and subsequent dilution did not diminish the inactivation effect, showing that this ion inhibits the enzyme prior to the binding to the substrate. Phosphorylated sugars, but not free sugar, inactivated the four reductase phosphatases. PPi-inactivated enzymes were reactivated by Mg2 or Mn2, this process being time-dependent. The four phosphatases had different patterns of reactivation. Phosphatases Ib and IIb (low-molecular mass forms) were shown to be different enzymes as judged by: their divergent behaviour when inhibited with Fe2; their PPi response; kinetics of reactivation by Mg2 or Mn2 or PPi-inactivated enzymes; and thermal stability. A metalloenzyme character is suggested for reductase phosphatases.

Adenine Nucleotides↗
PubMedDate not supplied

Regulation of intracellular pyrophosphatase-activity and conservation of the phosphoanhydride-energy of inorganic pyrophosphate in microbial metabolism.

The conservation of the phosphoanhydride-energy of inorganic pyrophosphate (PP) in microbial metabolism requires a stringent metabolic control of the intracellular pyrophosphatases (PPases, EC 3.6.1.1). In this article, the rate of intracellular PP-liberation during biosynthesis of cellular constituents is calculated from the specific growth rate and the macromolecular composition of the respective microorganism. This rate is compared with the maximal specific activity of PPase in cell free extracts or purified enzyme preparations in order to investigate the possibility of the limitation of biosynthesis through PPase-activity. The catalytic and regulatory properties of microbial PPases are discussed in respect to the occurrence of PP-dependent ransphosphorylases. The evidence showing that certain anaerobic microorganisms including photosynthetic bacteria, can use PP instead of ATP as phosphate donor for transphosphorylation reactions will be discussed.

Amino Acids↗
PubMedDate not supplied

Wound-induced respiration and pyrophosphate:fructose-6-phosphate phosphotransferase in potato tubers.

A seven fold increase in the rate of respiratory O2 uptake was observed 24 h after slicing of potato tuber disks. The maximum activity of pyrophosphate:fructose-6-phosphate phosphotransferase (PFP) was 5-7 times greater than that of ATP-dependent phosphofructokinase (PFK) in fresh or aged potato slices. Thus, PFP may participate in glycolysis which supplies respiratory substrate in potato tubers. The PFP activity of desalted extracts determined in the absence of fructose-2,6-bisphosphate (F2,6BP) increased by 4.5 fold 24 h after slicing. However, maximal PFP activity determined with saturating (1 microM) F2,6BP was not changed. The Ka values of PFP for F2,6BP was lowered from 33 to 7 nM after 24 h of aging treatment. This increased susceptibility of the PFP activity to its allosteric activator, F2,6BP, may be involved in the increased respiration in wounded disks of potato tubers. Immunoblotting experiments indicated that both the alpha (66 kDa) and the beta (60 kDa) subunits of PFP were present in fresh or 24 h aged tuber slices.

Kinetics↗
PubMed2005

An update on the treatment options for gout and calcium pyrophosphate deposition.

Gout and calcium pyrophosphate deposition disease are two common causes of inflammatory joint disease. Despite differences underlying their pathogenesis, their clinical presentation and treatment share some common features. Optimal treatment for both requires prompt resolution of acute synovitis, reduction of chronic joint damage and management of associated conditions. Available therapeutic interventions and future strategies are reviewed in this article.

Adrenal Cortex Hormones↗
PubMed2005

Reduced plasma pyrophosphate levels in hemodialysis patients.

Pyrophosphate (PPi) is a known inhibitor of hydroxyapatite formation and has been shown to inhibit medial vascular calcification in vitamin D-toxic rats. It was demonstrated recently that endogenous production of PPi prevents calcification of rat aorta that are cultured in high concentrations of calcium and phosphate. For determining whether PPi metabolism is altered in hemodialysis patients, plasma levels and dialytic clearance of PPi were measured in stable hemodialysis patients. Predialysis plasma [PPi] was 2.26 +/- 0.19 microM in 38 clinically stable hemodialysis patients compared with 3.26 +/- 0.17 in 36 normal subjects (P < 0.01). Approximately 30% of plasma PPi was protein bound, and this was not altered in dialysis patients. There was a weak inverse correlation with age in normal individuals but not in dialysis patients. Plasma [PPi] in dialysis patients was correlated with plasma [PO4(3-)] (r = 0.56) but not with [Ca2+], parathyroid hormone, or the dose of dialysis, and levels did not vary between interdialytic periods of 2 and 3 d. Plasma [PPi] decreased 32 +/- 5% after standard hemodialysis in 17 patients. In vitro clearance of PPi by a 2.1-m2 cellulose acetate dialyzer was 36%, and the mean PPi removal in five patients was 43 +/- 5 micromol, consistent with a similar in vivo clearance. Cleared PPi was greater than the plasma pool but less than the estimated extracellular fluid pool. Erythrocyte PPi content decreased 24 +/- 4%, indicating that intracellular PPi is removed as well. It is concluded that plasma [PPi] is reduced in hemodialysis patients and that PPi is cleared by dialysis. Plasma levels in some patients were below those that have previously been shown to prevent calcification of vessels in culture, suggesting that altered PPi metabolism could contribute to vascular calcification in hemodialysis patients.

Adult↗
PubMed2003

Calcium pyrophosphate dihydrate arthropathy with condylar destruction of the temporomandibular joint.

We report a case of calcium pyrophosphate dihydrate (CPPD) arthropathy with condylar destruction of the temporomandibular joint. Diagnosis was made on the basis of clinical findings and x-ray evidence of severe destruction of the condyle. The most likely diagnosis was considered to be neoplasm and a secondary infection of the left TMJ. Review of sections of the condyle taken at operation confirmed the diagnosis of left TMJ pseudogout. The postoperative course was uneventful with improvement in the clinical symptoms.

Adult↗
PubMed2005

Inorganic pyrophosphate (PPI) in pathologic calcification of articular cartilage.

Physiologic levels of extracellular PPi, which suppresses hydroxyapatite crystal growth, must be maintained by articular chondrocytes and resident cells in many othee tissues in order to prevent pathologic calcification. However, extracellular PPi rises in articular cartilage in direct association with aging. Matrix supersaturation with PPi stimulates chondrocalcinosis manifesting as calcium pyrophosphate dihydrate (CPPD) crystal deposition. Extracellular PPi levels are normally held in check by balances in PPi generation by nucleotide pyrophosphatase phosphodiesterase (NPP/NTPPPH) activity relative to PPi degradation by pyrophosphatases, by balance effects of cytokines and growth factors, and by transport of PPi from the cell interior involving the multiple-pass transmembrane protein ANK. But these mechanisms become dysrgulated in aging and osteoarthritic (OA) cartilage and extracellular PPi excess supervenes, mediated in large part by upregulated NPP1 and ANK expression in articular cartilage. Conversely, NPP1 and ANK deficiency states were recently linked to phenotypically similar forms of spontaneous soft tissue calcification with hydroxyapatite (HA). Here, we focus on recent advances in understanding of PPi metabolism and NPP1 and ANK function pertinent to the pathogenesis of pathologi matrix calcification in articular cartilage.

Animals↗
PubMed1992

Subcellular localization of transferrin and pyrophosphate in liver cells after perfusion in situ or incubation in vitro.

Rat livers were perfused in situ with [125I]-transferrin, FITC-dextran and [32P]-inorganic pyrophosphate (PP). In a parallel set of experiments rat liver homogenates was incubated with [125I]-transferrin and [32P]-PPi. In both sets of experiments cellular organelles were prepared by density gradient centrifugation in metrizamide. In the perfusion experiments [125I]-transferrin and FITC-dextran accumulated in fractions rich in plasma membrane enzymes, whereas in the homogenate experiments [125I]-transferrin remained in soluble fractions. [32P]-PPi remained in soluble fractions in both sets of experiments, i.e. PPi did not co-localize with transferrin taken up by intact cells. In another set of experiments fractions rich in endosomes were tested for their ability to synthesize PPi from ATP. No PPi was found. The results argue against a role for PPi in transferrin-iron release within endosomes.

Adenosine Triphosphate↗
PubMed1980

32P-pyrophosphate in the treatment of persistent metastatic bone pain.

Eight patients with persistent pain due to disseminated bone metastases from mammary carcinoma were given about 370 MBq (10 mCi) of 32P-pyrophosphate on 10 occasions. All but one of the patients experienced alleviation of pain lasting 1 to 4 months. The side effects, which derived mainly from haematopoetic tissue, prevent the routine use of this compound.

Blood Cell Count↗
PubMed1991

Hypophosphatasia and the extracellular metabolism of inorganic pyrophosphate: clinical and laboratory aspects.

Hypophosphatasia is a rare inherited disorder in which the activity of the bone/liver/kidney or tissue nonspecific form of alkaline phosphatase (ALP) is reduced. The clinical expression of the disease is highly variable, but in early life the severity tends to reflect the age of onset. Accordingly, the disease is often classified into perinatal, infantile, and childhood forms. Hypophosphatasia also occurs in adults. Some exhibit symptoms in adulthood for the first time, but others have a history of the disease in early life with an intervening symptom-free period. Defective mineralization of bones and teeth is the predominant clinical feature of all forms of the disease. Biochemically, the reduction in ALP activity is associated with alterations in the extracellular metabolism of various phosphorylated compounds, including inorganic pyrophosphate (PPi), phosphoethanolamine, and pyridoxal 5'-phosphate. Of these, PPi may have an especially important role in the development of the mineralization defect. Accordingly, the extracellular metabolism of PPi and its possible role in the regulation of mineralization will be discussed.

Adult↗
PubMed1978

Evaluation of fracture healing in man by serial 99mTcSn-pyrophosphate scintimetry.

Serial 99mTc-pyrophosphate (99mTcPP) uptake measurements were performed, during the healing period, in 12 patients with fracture of the distal end of the radius without displacement. A peak value in uptake ratio was seen within 4 weeks in all patients. For clinical reasons the patients were divided into a normal healing and a slow healing group. 99mTcPP uptake at 6 weeks after the fracture was significantly higher in the slow healing group. Quantitation of the healing process in forearm fractures is possible using 99mTcPP and a gamma camera, and concentrating on small selected areas of interest.

Adult↗
PubMed2005

Foraminal deposition of calcium pyrophosphate dihydrate crystals in the thoracic spine: possible relationship with disc herniation and implications for surgical planning. Report of two cases.

The authors report two cases of nodular calcium pyrophosphate dihydrate (CPPD) crystal deposition close to the thoracic neural foramen, which caused chronic radiculopathy. Preoperatively, the lesions were interpreted as calcified disc herniations. Both patients underwent surgery in which an extended transfacet pedicle-sparing approach was used. Incision of the posterior longitudinal ligament released soft degenerated material. In both cases, histological examination showed abundant degenerative debris along with CPPD crystals. Spinal CPPD deposition is a comparatively rare disease that almost invariably involves the posterior aspect of the spinal canal, typically the ligamentum flavum. The exceptional foraminal location of the lesions reported here, combined with the surgical findings, indicated that the CPPD crystals were deposited on a laterally herniated disc fragment. A distinctive feature in both cases was the soft consistency of the resected tissue. The consistency of the disc material and the location of the lesion in the axial plane (that is, median compared with lateral) are key factors in determining the optimal surgical approach to thoracic disc herniations. In describing consistency, terms such as "calcified" and "hard" have been used interchangeably in the literature. In the cases reported here, what appeared on computerized tomography and magnetic resonance imaging studies to be densely calcified lesions were shown intraoperatively to be soft herniations. The authors' experience underscores that not all densely calcified herniated discs are hard. Although detection of this discrepancy would have left surgical planning for the lateral disc herniations unchanged, it could have altered planning for centrally or centrolaterally located disc herniations.

Adult↗
PubMed1989

Calcium, lanthanum, pyrophosphate, and hydroxyapatite: a comparative study in fibroblast mitogenicity.

Calcium-containing crystals and elevated levels of calcium chloride (CaCl2) and lanthanum chloride (LaCl3) have been previously reported to enhance the proliferative activity of cultured fibroblasts. We have investigated the relative mitogenicity of these agents, whether they function via precipitation on the cell surface and whether they interact with one another. Confluent cultures of newborn foreskin fibroblasts provided with fresh medium containing 10% fetal bovine serum (FBS) in the presence of hydroxyapatite (HA), pyrophosphate (PPi), LaCl3 (La), or additional CaCl2 (Ca) were all stimulated more than control cultures provided with fresh medium and 10% FBS alone as assessed by cell counts 5 days later. Increases in cell yield above the original confluent cell density were 316% for La, 271% for Ca, 189% for HA, 131% for PPi, and 45% for controls. Addition of fresh medium containing 10% FBS and epidermal growth factor or fresh medium containing 20% FBS as additional points of reference yielded increases of 204 and 107%, respectively, over original confluent density. Stimulation induced by La or Ca was significantly greater (P less than 0.001) than the stimulation induced by each of the other treatments. The same treatments added to confluent cultures without a change of medium also renewed mitotic activity, with La and Ca again the most mitogenic and approximately doubling the pretreatment cell yields. Cultures incubated in an inverted position to avoid cell contact with precipitates in the medium were also stimulated by La and Ca, but not by HA and PPi. When added to confluent cultures simultaneously supplemented with optimal additional Ca, La decreased Day 5 cell yields in a dose-dependent manner at low concentrations (0.03-0.2 mM) but increased cell yields over those obtained with 0.2 mM LaCl3 again in a dose-dependent manner at higher concentrations. Thus, while HA and PPi act via precipitation on the cell surface, the more mitogenic agents La and Ca function in solution and appear to stimulate cell division by different nonadditive mechanisms. These findings suggest multiple mechanisms of membrane participation in mitogen responsiveness and in density-dependent inhibition of growth.

Calcium Chloride↗
PubMed2002

A case of calcium pyrophosphate dihydrate crystal deposition disease presenting as an acute polyarthritis.

We report a case of calcium pyrophosphate dihydrate crystal deposition disease (CPDD) presenting as an acute polyarthritis. A 66-yr-old woman was admitted with a 5-day history of fever and multiple joint pain including wrists, elbows, shoulders, knees, and ankles developed 5 days before admission. Her plain radiographs of wrists, elbows, shoulders, knees, and ankles showed chondrocalcinosis. The pubic symphysis, lumbar intervertebral discs, and both hip joints, which were asymptomatic, also had calcium deposits. The compensated polarized microscopic examination of the joint fluid, aspirated from the right knee revealed intracellular and extracellular weakly positive birefringent crystals, confirming the CPDD. This case showed that CPDD may manifest as an acute polyarthritis mimicking acute onset rheumatoid arthritis.

Acute Disease↗
PubMed1980

[Evaluation of the left ventricular function by myocardial scintigram and radionuclide angiocardiography with technetium-99m pyrophosphate in patients with acute myocardial infarct (author's transl)].

Myocardial scintigrams with 99mTc-pyrophosphate (PYP) were performed in 30 patients with acute myocardial infarct (AMI) and positive scintigrams were obtained in the 24 patients. In 12 patients the size of the AMI estimated from the scintigram with 99mTc-PYP was compared with the pulmonary capillary wedge pressure (PCWP). In the 7 patients with PCWP below 10 mmHg the mean area of the AMIs was 22 +/- 5.5 cm2 and that of in the 5 patients with PCWP beyond 10 mmHg was 41 +/- 12.4 cm2. This difference was statistically significant (p less than 0.05). In comparison with chest X-ray findings, the average size of the AMIs among 6 patients with alveolar and/or interstitial edema was 43 +/- 11.9 cm2 and that of among 8 patients without pulmonary edema was 25 +/- 9 cm2. The left ventricular ejection fraction (LVEF) was obtained by first pass method. In 12 patients LVEF and PCWP was compared. The 7 patients with PCWP below 10 mmHg did show significantly larger LVEF (49 +/- 8.2%) than that of 5 patients with PCWP beyond 10 mmHg (33 +/- 6.1%) (p less than 0.01). The mean LVEF in the 7 patients with pulmonary edema was 35 +/- 10.2% and that of in the 8 patients without pulmonary was 48 +/- 5.3%. Myocardial scintigram and radionuclide angiocardiography with 99mTc-PYP were useful for evaluation of the left ventricular function as well as detection of the AMI.

Acute Disease↗
PubMed2001

[Diff-Quik(R) staining method for detection and identification of monosodium urate and calcium pyrophosphate crystals in synovial fluids]

The aim of this study was to evaluate whether DQ could prove useful to identify monosodium urate (MSU) and calcium pyrophosphate dehydrate (CPPD) crystals on permanent mounted stained slides. To this end, we studied 27 synovial fluid (SF) samples obtained from the knees of patients with the pseudogout (n=21) and acute gouty arthritis (n=6). Wet analysis for crystal detection and identification was performed within one hour of joint aspiration. In addition, we studied 16 inflammatory synovial effusions obtained from patients with knee arthritis not induced by crystals. For each SF, DQ stained slides were analyzed by 2 experienced doctors in SF analysis. The observers were blinded to the type of crystal present in the SF. Each slide was analyzed by compensated polarized and transmitted light microscopy. SF was considered positive if intracellular and/or extracellular crystals were clearly identified. In addition, the observers were asked to identify the type of the crystals using compensated polarized light microscopy. Sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) of the DQ staining method were determined. 51 true positive and 28 true negative specimens were correctly classified (39 CPPD samples, 12 MSU samples, and 28 samples of crystals-unrelated arthropathies). All MSU specimens were correctly diagnosed.

Journal Article↗
PubMed2001

[Compressive cervical myelopathy due to massive periodontoid calcium pyrophosphate crystal deposition]

A 77 year-old man suffering from psoriatic arthropathy presented with progressive myelopathy due to massive deposits of calcium pyrophosphate dihydrate crystals in peri-odontoid tissue. The magnetic resonance imaging and computer tomographic pictures of the involved site are shown and discussed. The clinical spectrum of crystal deposition disease involving the atlo-axial joint is briefly reviewed.

Journal Article↗