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 307 records · Page 17Linked to original sources
PubMed1990

Localization of In-111 antimyosin Fab and 99mTc-pyrophosphate in reperfusion myocardial infarction model.

The myocardial uptake of In-111 antimyosin Fab and Tc-99m pyrophosphate was studied in dogs undergoing coronary artery occlusion for 90 minutes followed by reperfusion. The regional myocardial blood flow was determined by injecting Sc-46 labeled microsphere and was related to the relative concentrations of In-111 antimyosin and Tc-99m pyrophosphate. There was an inverse linear correlation between In-111 antimyosin Fab localization and the regional blood flow in both the subendocardial (r = 0.81) and subepicardial myocardium (r = -0.80). The greatest uptake of antimyosin was observed in areas of severe blood flow reduction (0-10% of normal). On the other hand, there was no correlation between the Tc-99m pyrophosphate uptake and the degree of blood flow reduction. Maximal subendocardial localization of Tc-99m degree of blood flow reduction. Maximal subendocardial localization of Tc-99m pyrophosphate was observed in areas where the blood flow was reduced to 31-50% of the normal. In the case of the subepicardium, the greatest uptake was localized to areas of 0 to 10% of the normal flow. In addition, there was significant myocardial uptake in regions where the blood flow was minimally reduced (greater than 81%). This study suggests that In-111 antimyosin Fab is a specific and quantitative tool in the evaluation of myocardial necrosis.

Animals↗
PubMed1990

Calcium pyrophosphate crystal deposition: a kinetic study using a type I collagen gel model.

Calcium pyrophosphate dihydrate (CPPD) crystal deposition disease is characterized by deposits of triclinic (t) and monoclinic (m) CPPD crystals in articular and fibrocartilage. Many investigators have attempted to model CPPD crystal growth using both solution and a variety of gel systems. We have investigated the effect of type I collagen fibrils on CPPD crystal nucleation and growth using an ionic diffusion model. Collagen was isolated from porcine menisci using a pepsin solubilization procedure and gelled in three layers, with one containing 10 mM pyrophosphate (PPi) plus physiologic ions, the middle containing only the ions, while the third contained 25 mM Ca plus physiologic ions. Initially, amorphorous calcium pyrophosphate formed at the Ca-PPi interface. Monoclinic CPPD crystallized in 6 weeks when the [Ca] was between 2 and 3 mM and the [PPi] was between 50 and 75 microM. At 13 weeks, t-CPPD formed when the [Ca] was also between 2 and 3 mM, but the PPi was less than 25 microM. One of the most striking differences between this system and all previous solution and gel model systems is the total absence of orthorhombic calcium pyrophosphate tetrahydrate (o-CPPT) from the gels made of collagen fibrils in near native conformation. Further, crystals of t-CPPD appear as large single crystals with the classic prismatic growth habit observed in vivo, and crystals of m-CPPD also evidence the in vivo rod habit. In contrast, the crystal growth habits of t-CPPD, m-CPPD, and o-CPPT grown in all of the other model systems never matched that observed in vivo. When compared to the previous studies, these results, particularly the crystal growth habit data, suggest that the native collagen fibrils themselves can nucleate CPPD crystal formation.

Animals↗
PubMed1979

[Arthropathies due to calcium pyrophosphates].

Articular chondrocalcinosis results from the deposits of calcium pyrophosphate microcrystals in the articular hyalin and fibrocartilages, the synovium and at times the tendons. In our area it is seen most frequently as isolated cases in the elderly and may be asymptomatic. When the affected joints present clinical manifestations, they vary from acute to subacute or chronic recurrent arthritis. A marked articular destruction can be observed in some cases. There is a classical radiological picture: linear opacities are most frequently seen localized in the mid-zone layer of the hyalin cartilage running parallel to but at a certain distance from the bone cortex. A part of our research has shown that in contrast to urate gout, articular chondrocalcinosis results from a metabolic disturbance of the calcium pyrophosphate localized almost exclusively in the same articular structures. Precise information is lacking at the present time to explain why calcium pyrophosphate mycrocrystals accumulate in the cartilage, the synovium and at times at the tendons; nor do we understand the precise role played by the pyrophosphate in bone and cartilage destruction.

Aged↗
PubMed1989

[Introduction of an enzyme method for determining pyrophosphate in urine--a comparative study between patients with calculi and normal probands].

Interest aroused towards pyrophosphate as a possible inhibitor in calcium oxalate and phosphate lithiasis. A procedure for the quantitative determination of pyrophosphate in urine suitable for use in clinical laboratories is described. The reproducibility of the method was assessed by within-run and between-run reproducibility studies and the accuracy of the method was obtained by determining the amount of pyrophosphate recovered in urine samples. The present study compares the pyrophosphate excretion and concentration between a control group and a calcium oxalate stone former group.

Calcium Oxalate↗
PubMed1985

[Accumulation of pyrophosphate in the myocardium in post-infarction cardiosclerosis].

A study of the relationship between the frequency of labelled pyrophosphate detection in the heart muscle and the incidence of clinical signs of heart failure or angina in 185 postmyocardial-infarction patients demonstrated that the distribution of patients with postinfarction cardiosclerosis among the positive and negative 99mTc-pyrophosphate scintigraphy groups was governed by the presence of heart failure in these patients, a finding suggestive of the scarry fields within the myocardium as the principal cause of myocardial accumulation of labelled pyrophosphate in postinfarction cardiosclerosis. Pyrophosphate accumulation in patients with postinfarction cardiosclerosis can be regarded as an indicator of unfavorable developments, as confirmed by one-year follow-up results in 114 patients.

Adult↗
PubMed1987

Recognition of reversible and irreversible myocardial injury by technetium pyrophosphate extraction kinetics.

The need for a more accurate method of detecting episodes of myocardial ischemia during cardiac operations, particularly during the ischemic arrest interval, prompted us to investigate the usefulness of measuring the active extraction of technetium pyrophosphate in identifying and quantitating ischemic injury. Twenty-four adult mongrel dogs were subjected to cardiopulmonary bypass, and normothermic global ischemia was induced by cross-clamping the proximal aorta. Technetium pyrophosphate (1 mCi) was injected through a standard cardioplegia line with normal saline, simulating administration of cardioplegic solution, upon placement of the aortic cross-clamp (time 0), at 15, 30, 45, and 60 minutes of global ischemia, and with the onset and completion of ischemic contracture. Radioactive counts were recorded over the heart at 1 second intervals, and the extraction fraction and half-time of clearance were calculated. The extraction fraction increased from 0.22 at time 0 to 0.58 at 15 minutes, 0.82 at 30 minutes, 0.85 at 45 minutes, and 0.91 at 60 minutes. The halftime increased from a baseline of 114 seconds (time 0) to a maximum of 321 seconds at 60 minutes of ischemia. The onset and completion of ischemic contracture showed a return toward baseline of both the extraction fraction and halftime of clearance, with an extraction fraction of 0.44 and 0.46 and a halftime of 135 and 133 seconds, respectively. These data clearly show that reversible myocardial injury increased the extraction and reduced the clearance of technetium pyrophosphate and that the magnitude of change related to the extent of injury. The progression to irreversible myocardial injury decreased the active extraction of technetium pyrophosphate. This simple procedure for real-time documentation of myocardial injury promises to provide easily obtainable endpoints of injury for use during cardiac operations in humans.

Animals↗
PubMedDate not supplied

The effect of calcium and magnesium ions on calcium pyrophosphate crystal formation in aqueous solutions.

Calcium pyrophosphate crystal formation has been associated clinically with hypercalcemic states (hyperparathyroidism) and hypomagnesemia. We studied aqueous solutions at pH 7.4, 37 degrees C, [Na+] = 140 nM over a range of calcium chloride/magnesium chloride/sodium pyrophosphate concentrations to determine the effect of calcium and magnesium ions on crystal formation. We found that CPPD(T) and CPPD(M) could form under different ionic conditions. Low [Mg++] and [PPi] favoured CPPD(T) whereas higher [Mg++] and [PPi] favoured CPPD(M). At [Mg++] = 1.0 mM a calcium magnesium pyrophosphate crystal phase designated CMPP2 formed. As [Mg++] affects the crystal phase formed more than equimolar [Ca++], we conclude that ionic magnesium deficiency may be a clinically important determinant in calcium pyrophosphate dihydrate crystal formation.

Calcium↗
PubMed1984

Pyrophosphate arthropathy as a late complication of juvenile chronic arthritis.

Pyrophosphate arthropathy is an age-related disease rarely seen in those under 45 years of age. We report 2 patients with early onset pyrophosphate arthropathy in joints previously affected by juvenile chronic arthritis. This previously undescribed association supports the hypothesis that joint damage may predispose to calcium pyrophosphate dihydrate crystal deposition and lead to secondary pyrophosphate arthropathy.

Adult↗
PubMed2003

Farnesyl pyrophosphate promotes and is essential for the binding of RACK1 with beta-tubulin.

Receptors for activated C kinase (RACKs) are a group of protein kinase C (PKC) binding proteins that have been shown to be crucial in the translocation and subsequent functioning of PKC on activation. RACK1 isolated from BALB/3T3 cells transformed with S-ras(Q61K) exhibits receptor activity for PKCgamma as competent as that of RACK1 from BALB/3T3 cells without transformation. However, the ability of RACK1 from transformed cells to bind with beta-tubulin peptide specific for Taxol (PEPtaxol) is defective. Interestingly, when farnesyl pyrophosphate was added at the submicrogram level, the association between RACK1 and PEPtaxol was enhanced significantly in a dosage-dependent manner. A parallel finding for the enhanced effect of farnesyl pyrophosphate on tubulin binding was established with mice RACK1 expressed in vitro. On the other hand, geranylgeranyl pyrophosphate, and retinoic acid failed to modulate the binding between RACK1 and tubulin. The dissociation of RACK1 and tubulin was not effective at damaging the binding between RACK1 and membrane receptor integrin beta1 in transformed cells. These findings indicate that depletion of farnesyl pyrophosphate provides a mechanism to seal PKC signaling on the membrane with immobile RACK1 and to divert cells to aberrant growth, such as transformation.

3T3 Cells↗
PubMed1995

Farnesyl pyrophosphate synthase from white lupin: molecular cloning, expression, and purification of the expressed protein.

Plants produce a variety of sesquiterpenoid compounds with diverse biological functions, whose synthesis is initiated by farnesyl pyrophosphate synthase [EC 2.5.1.1, EC 2.5.1.10]. The lack of availability of molecular tools to analyze this enzyme has, thus far, prevented the study of its expression and regulation in plants. A DNA fragment corresponding to a portion of the farnesyl pyrophosphate synthase gene was amplified by the polymerase chain reaction using was amplified by the polymerase chain reaction using degenerate primers designed from two highly conserved domains (FLV(A/L)DD(I/M)MD and FQIQDDYLD) found in eukaryotic farnesyl pyrophosphate synthase sequences. A clone, pS19, of a 438-bp PCR fragment was used to screen a white lupin root cDNA library. Two full-length cDNA clones (pFPS1 and pFPS2) were isolated and sequenced, and one of them (pFPS2) was expressed in a bacterial system and the enzyme protein encoded by the clone was purified. The 1345-bp insert of pFPS2 contains a 1026-bp open reading frame, encoding a 342-amino-acid peptide with a calculated molecular mass of 39,310 Da. The deduced amino acid sequence of lupin farnesyl pyrophosphate synthase pFPS2 shares 90 and 79% identity with those from Lupinus albus (pFPS1) and Arabidopsis thaliana, respectively, 51% with the yeast enzyme, and 44% identity with those from rat and human. The overexpressed protein, which was purified to near homogeneity, displayed both dimethylallyl transferase and geranyl transferase activities. Polyclonal antibodies raised against the purified protein immunorecognized a ca 39-kDa protein in lupin root extracts.

Alkyl and Aryl Transferases↗
PubMed1991

Flexibility of myosin in pyrophosphate and NaCl solutions. An electric birefringence study.

The orientational relaxation time of myosin has been reported as 38 microseconds when measured in pyrophosphate media at elevated pH (Hvidt et al. 1984) and as 17 microseconds when measured in 0.3 M KCl at pH 7.3 (Bernengo and Cardinaud 1982). This discrepancy, which is reexamined in the present report, suggests that in KCl solution the rod portion of the myosin molecule is bent with an average angle close to 110 degrees, whereas in pyrophosphate at elevated pH it assumes a nearly straight and rigid conformation. Electric birefringence shows that the amount of dimeric and polymeric species in pyrophosphate media at pH's 8.0 and 8.5 is certainly greater than usually thought. In these media, relaxation times can be measured correctly at pH 9.0. A comparative analysis of the influence of protein concentration, field strength, medium composition and concentration, pH and temperature showed that a high relaxation time is associated with the presence of pyrophosphate and that the myosin tail is significantly stiffened in the presence of this anion.

Animals↗
PubMed1992

Structure of the sugar-phosphate moiety of lipid A from lipooligosaccharide of Neisseria meningitidis group B, strain BC5S No. 125. Hydrolytic stability of phosphate and pyrophosphate substituents.

On the basis of chemical and NMR data the partial structure of lipid A from lipooligosaccharide (LOS) of Neisseria meningitidis group B, strain BC5S No 125 was established. Lipid A consisted of disaccharide 2-deoxy-6-O-[2-deoxy-2-(3-hydroxytetradecanoylamino)- beta-gluco-pyranosyl]-2-(3-hydroxytetradecanoylamino)- alpha-glucopyranose carrying the beta-(2-aminoethyl)pyrophosphate residue at 0-4' and the pyrophosphate or phosphate residue at 0-1. On hydrolysis of the acidic form of LOS with 1% acetic acid the substituent at 0-1 was practically completely removed whereas that at 0-4' was stable. The analogous hydrolysis of the Mg-salt of LOS was accompanied by splitting off the pyrophosphate linkage in the substituent at 0-4'. Hydrolysis of LOS at pH 4.5 in the presence of SDS led mainly to a lipid A preparation retaining both pyrophosphate residues.

Antigens, Bacterial↗
PubMed1999

Phosphofructokinase activities within the order spirochaetales and the characterisation of the pyrophosphate-dependent phosphofructokinase from spirochaeta thermophila

The subtype of phosphofructokinase activity, either ATP-, ADP- or pyrophosphate-dependent, present in members of three genera from the Spirochaetales was investigated. The individual species/strains examined included Spirochaeta alkalica, S. asiatica, S. halophila, S. isovalerica, S. litoralis, S. zuelzerae, S. thermophila, two thermophilic spirochetes, Treponema bryantii, T. denticola, paragraph signT. pectinovorum, Leptospira biflexa and L. interrogans. All of the Spirochaeta strains, regardless of their phenotype, possessed primarily a pyrophosphate-dependent phosphofructokinase. In contrast, T. bryantii, T. denticola and L. biflexa had predominantly an ATP-dependent activity, whereas no activity was detected in T. pectinovorum or paragraph signL. interrogans. The results suggest that pyrophosphate-dependent phosphofructokinase activity may be a reliable phenotypic marker for the genus Spirochaeta and that there are potentially interesting differences in how the catabolism of saccharides is controlled among members of genera within the Spirochaetales. The pyrophosphate-dependent phosphofructokinase from S. thermophila strain RI 19.B1 was purified (303-fold) to homogeneity and biochemically characterised. The S. thermophila enzyme displayed hyperbolic kinetics with respect to both the forward and reverse cosubstrates and was not significantly affected by traditional activators or inhibitors of phosphofructokinase. The biochemical characterisation represents the first spirochete phosphofructokinase to be described.

Journal Article↗
PubMed2000

Effects of phytate and pyrophosphate on brushite and hydroxyapatite crystallization. Comparison with the action of other polyphosphates.

This is a comparative study of the effects of phytate and pyrophosphate and other polyphosphates on the crystallization of hydroxyapatite and brushite, the most frequent calcium phosphates involved in calcium oxalate urolithiasis. Brushite and hydroxyapatite crystal formation was studied in synthetic urine, through kinetic-turbidimetric measurements that allowed evaluation of the inhibitory effects on crystallization of insoluble salts. The effectiveness in preventing brushite crystallization decreases in the sequence phytate > polyphosphate > EDTPO > etidronate > pyrophosphate > triphosphate > medronate; whereas the order of effectiveness in preventing hydroxyapatite crystallization was EDTPO > etidronate = pyrophosphate > triphosphate > medronate > polyphosphate > phytate. Phytate, a natural inhibitor in urine, most effectively blocked brushite precipitation (1.21x10(-5) M prevented crystallization during time periods of at least 1 h), and pyrophosphate was the natural inhibitor that most effectively blocked hydroxyapatite precipitation (2.87x10(-6) M prevented crystallization during time periods of at least 1 h). This demonstrates that low excretion of these substances would pose a risk of renal lithiasis.

Calcium Phosphates↗
PubMed1999

Purification and properties of the pyrophosphate-dependent phosphofructokinase from Dictyoglomus thermophilum Rt46 B.1.

The distribution of phosphofructokinase phosphoryl donor subtypes (ATP-, ADP-, and pyrophosphate) in the deeply rooted phylogenetic lineages of thermophiles is of interest with regard to the evolution of phosphofructokinase activity and of the Embden-Meyerhof pathway. In this article we present the first biochemical description of a thermostable pyrophosphate-dependent phosphofructokinase from the hyperthermophilic bacterium Dictyoglomus thermophilum. The enzyme was not allosterically controlled by traditional modulators of phosphofructokinases and has significant activity with tripolyphosphate and polyphosphate. Kinetic parameters of the enzyme suggest it plays primarily a glycolytic role. The enzyme required Mg2+ for optimal activity, was partially activated by some monovalent and divalent cations, and was strongly inhibited by Cu2+. The sequence of the 21 N-terminal residues suggests that the enzyme is most similar to the pyrophosphate-dependent phosphofructokinases from Amycolatopsis methanolica and the hyperthermophilic crenarchaeon Thermoproteus tenax, enzymes which have been suggested to represent an ancient lineage of phosphofructokinases (Siebers et al. 1998). The unexpected finding of a pyrophosphate-dependent phosphofructokinase in Dictyoglomus thermophilum, which is phylogenetically related to Thermotoga maritima, previously shown to possess an ATP-dependent phosphofructokinase activity, is discussed.

Amino Acid Sequence↗
PubMed1980

Thallium-201 versus technetium-99m pyrophosphate myocardial imaging in detection and evaluation of patients with acute myocardial infarction.

Thallium-201 myocardial imaging is of value in the early detection and evaluation of patients with suspected acute infarction. The extent of a thallium defect in an initial myocardial image may have important prognostic value. Tomographic imaging techniques hold promise for increased diagnostic sensitivity and more accurate quantitation of both infarcted and residual viable myocardium. Thallium imaging may have a special value in characterizing patients with cardiogenic shock and in detecting patients at risk for subsequent infarction or death or death or both, before hospital discharge. Approximately 95 percent of patients with transmural or nontransmural myocardial infarction can be detected with technetium-99m pyrophosphate myocardial imaging if the imaging is performed 24 to 72 hours after the onset of symptoms. Pyrophosphate imaging has been useful in localizing the site and determining the extent of acute myocardial infarction. The "doughnut" pattern is associated with a relatively large incidence of subsequent congestive heart failure and death. However, the clinical utility of this information is limited because it is usually not available when it is most needed, on admission to the coronary care unit. Pyrophosphate imaging may have an important role in the evaluation of patients during the early follow-up period after hospital discharge from an episode of acute infarction. The finding of a persistently positive pyrophosphate image suggests a poor prognosis and is associated with a relatively large incidence of subsequent myocardial infarction and death.

Acute Disease↗
PubMed1991

High-performance liquid chromatographic determination of pyrophosphate in the presence of a 20,000-fold excess of orthophosphate.

An HPLC method was based on anion-exchange separation of pyrophosphate (diphosphate) and orthophosphate and postcolumn spectrophotometric detection at 140 degrees C with a molybdenum(V)-molybdenum(VI) reagent. The reagent was easy to prepare, stable for at least 6 months at room temperature, and ready for the determination of pyrophosphate and orthophosphate by the so-called heteropoly blue method without use of any reducing agent. A photodiode-array detector for HPLC indicated the spectral characteristics of the heteropoply blue complex that was detectable at 330-800 nm. The HPLC method had a wide dynamic range from 3 x 10(-7) to 5 x 10(-4) M for both pyrophosphate and orthophosphate with a relative standard deviation of measurement of 10 approximately 2%. Pyrophosphate of 5 x 10(-7) and 5 x 10(-6) M, respectively, could be determined in the presence of a 20,000-fold excess of orthophosphate; 0.01 and 0.1 M.

Chromatography, High Pressure Liquid↗
PubMed1984

Undecaprenyl pyrophosphate synthetase from Lactobacillus plantarum: a dimeric protein.

a++Undecaprenyl pyrophosphate synthetase has been purified from Lactobacillus plantarum. It catalyzes the formation of a C55 polyprenyl pyrophosphate having isoprene residues with cis stereochemistry. The enzyme was shown to be an acidic protein (pI = 5.1), which can be partially purified by preparative gel electrophoresis and Blue-agarose column chromatography. The Km's of the enzyme for its substrates t,t-farnesyl pyrophosphate and isopentenyl pyrophosphate were determined to be 0.13 and 1.92 microM, respectively. The molecular weight of the enzyme was estimated by molecular sieve chromatography and gradient centrifugation to be 56,000 +/- 4000. Analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis indicated that the protein was composed of a dimer of 30,000-Da subunits. The enzyme was inactivated by the arginine-specific reagents phenylglyoxal, butanedione and, cyclohexanedione, but this inactivation was not prevented by either of the substrates.

Alkyl and Aryl Transferases↗