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Inorganic Phosphate Concentration (inorganic + phosphate_concentration)

Distribution by Scientific Domains

Medical Sciences	50%

Selected Abstracts

Electrosprayed Enzyme Coatings as Bioinspired Alternatives to Bioceramic Coatings for Orthopedic and Oral Implants

ADVANCED FUNCTIONAL MATERIALS, Issue 5 2009
Lise T. de Jonge
Abstract The biological performance of orthopedic and oral implants can be significantly improved by functionalizing the non-physiological metallic implant surface through the application of biologically active coatings. In this paper, a cost-effective alternative to traditional biomedical coatings for bone substitution through exploitation of the specific advantages of the electrospray deposition technique for the immobilization of the enzyme alkaline phosphatase (ALP) onto the implant surface is presented. Since ALP increases the local inorganic phosphate concentration required for physiological mineralization of hard tissues, ALP coatings will enable enzyme-mediated mineralization onto titanium surfaces. To evaluate the bone-bioactive capacity of the ALP-coated titanium surface, soaking experiments are performed. Although the purely inorganic so-called simulated body fluid is the standard in vitro procedure for predictive studies on potential bone bonding in vivo, an alternative testing solution is proposed that also contains organic phosphates (cell culture medium supplemented with the organic ,-b; -glycerophosphate (,-b; -GP) and serum proteins), thereby resembling the in vivo conditions more closely. Under these physiological conditions, the electrosprayed ALP coatings accelerated mineralization onto the titanium surface as compared to noncoated implant material by means of enzymatic pathways. Therefore, this novel approach toward implant fixation holds significant promise. [source]

Contrasts in cortical magnesium, phospholipid and energy metabolism between migraine syndromes.

HEADACHE, Issue 4 2003
MD Boska
Neurology. 2002;58:1227-1233. BACKGROUND: Previous single voxel (31)P MRS pilot studies of migraine patients have suggested that disordered energy metabolism or Mg(2+) deficiencies may be responsible for hyperexcitability of neuronal tissue in migraine patients. These studies were extended to include multiple brain regions and larger numbers of patients by multislice (31)P MR spectroscopic imaging. METHODS: Migraine with aura (MWA), migraine without aura (MwoA), and hemiplegic migraine patients were studied between attacks by (31)P MRS imaging using a 3-T scanner. RESULTS: Results were compared with those in healthy control subjects without headache. In MwoA, consistent increases in phosphodiester concentration [PDE] were measured in most brain regions, with a trend toward increase in [Mg(2+)] in posterior brain. In MWA, phosphocreatine concentration ([PCr]) was decreased to a minor degree in anterior brain regions and a trend toward decreased [Mg(2+)] was observed in posterior slice 1, but no consistent changes were found in phosphomonoester concentration [PME], [PDE], inorganic phosphate concentration ([Pi]), or pH. In hemiplegic migraine patients, [PCr] had a tendency to be lower, and [Mg(2+)] was significantly lower than in the posterior brain regions of control subjects. Trend analysis showed a significant decrease of brain [Mg(2+)] and [PDE] in posterior brain regions with increasing severity of neurologic symptoms. CONCLUSIONS: Overall, the results support no substantial or consistent abnormalities of energy metabolism, but it is hypothesized that disturbances in magnesium ion homeostasis may contribute to brain cortex hyperexcitability and the pathogenesis of migraine syndromes associated with neurologic symptoms. In contrast, migraine patients without a neurologic aura may exhibit compensatory changes in [Mg(2+)] and membrane phospholipids that counteract cortical excitability. Comment: If the theory of hyperexcitability of migraine brain is correct, basic scientists will need to find clear markers for the neuronal abnormalities that underlie this excitability. Using their techniques, these researchers could not find such markers. SJT [source]

Characterisation of pressure-treated skimmed milk powder dispersions: application of NMR spectroscopy

JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 10 2002
Colin D Hubbard
Abstract Skimmed milk powder (SMP) (bovine) and skimmed milk powder/sucrose dispersions before, during and after high-pressure treatment have been studied by nuclear magnetic resonance (NMR) spectroscopy (principally P-31). The P-31 spectra of samples at 293,K before and after pressure (400,600,MPa) treatment were not significantly different from one another, whether or not sucrose was present. This indicates that physicochemical changes relating to phosphorus-containing components occurring during a pressure cycle are either reversible or result in re-immobilisation, while protein components may be rearranged. The P-31 NMR spectra of these dispersions at 293,K under pressure (100,300,MPa) showed that pressure caused a considerable increase in the free inorganic phosphate concentration and that the increase was proportional to the magnitude of pressure. Decompression to ambient caused an exact reversal of this trend. These findings are discussed in terms of characterisation and properties of pressure-treated SMP dispersions by other methods and techniques. © 2002 Society of Chemical Industry [source]

Biliary inorganic phosphate as a tool for assessing cold preservation-reperfusion injury: A study in the isolated perfused rat liver model

LIVER TRANSPLANTATION, Issue 2 2003
Luciana L. Almada
Ischemia-reperfusion injury is a major cause of early graft dysfunction after liver transplantation. The bile flow has been suggested as an index of ischemic damage, and severely impaired bile flow seems to be predictive of poor survival in experimental studies. Looking for injury markers, biliary inorganic phosphate has the potential of being a useful endogenous marker of diminished hepatobiliary function because this anion is excreted in the bile by a paracellular pathway and it can detect changes in permeability. The goal of this study was to evaluate the effects of cold preservation-reperfusion of the liver on bile flow and bile inorganic phosphate and their relationship with storage-related graft failure. The isolated and perfused rat liver was used to evaluate the injury for ischemia-reperfusion. The intrahepatic resistance, lactate dehydrogenase release, and potassium and biliary inorganic phosphate concentration were used to estimate viability and function of freshly isolated or cold-preserved livers. The intrahepatic resistance and the bile flow were consistent and significantly decreased throughout the perfusion time in relation to the increment in storage. Inorganic phosphate is more concentrated in bile from preserved livers, showing an alteration in paracellular pathway, confirmed by the biliary excretion of horseradish peroxidase. After preservation, concentration and excretion of the paracellular marker were increased during the first peak. The second peak appears earlier in preserved livers (10 minutes) with a different shape but without changes in concentration. In conclusion, inorganic phosphate in bile shows changes in paracellular permeability as occurs in livers after 48 hours of cold preservation. [source]