Non-invasive assessment of muscle oxygenation may aid in optimising transfusion threshold decisions in ambulatory paediatric patients.

OBJECTIVE: To assess the potential utility of a novel non-invasive muscle oxygen measurement to determine the presence of muscle hypoxia in patients with anaemia. BACKGROUND: Recent assessment of the risk/benefit ratio of blood transfusion has led to clinical strategies optimising transfusion decisions. These decisions are primarily based on haematocrit (Hct) but not oxygen delivery, the primary function of red blood cells (RBCs). We hypothesised that muscle oxygenation (MOx) would correlate with Hct in patients with anaemia and may be a physiologically relevant determinant of the transfusion threshold. METHODS/MATERIALS: MOx was non-invasively determined in children in the Cancer and Blood Disorders Center ambulatory clinic at Seattle Children's Hospital using a custom-designed optical probe and spectrometer. MOx was compared with contemporaneous Hct. In subjects receiving RBCs, MOx and Hct were also determined following transfusion. RESULTS: MOx ranged from 36·7 to 100%, and Hct ranged from 17·0 to 38·6% in 27 measurements from 16 patients. High MOx values were associated with high Hct. Mean MOx for patients with normal Hct for age (n = 5) was 95·9 ± 2·9%. RBC transfusion increased mean Hct from 19·1 ± 1·5% to 29·3 ± 2·0 and mean MOx from 67·9 ± 21·1% to 89·9 ± 9·8%. Among six transfusion episodes (in five patients) with initial Hct < 22, only three had a pre-transfusion MOx of <70%. Patients with the lowest pre-transfusion MOx had the largest increase in MOx after transfusion. CONCLUSIONS: These preliminary data suggest that MOx may aid in making transfusion decisions when used in combination with Hct.

Solid state NMR study and density functional theory (DFT) calculations of structure and dynamics of poly(p-xylylenes).

High resolution solid state (13)C nuclear magnetic resonance (SS NMR) measurements were carried out on poly(p-xylylene) (PPX). The samples comprised vapor-deposited specimens as well as pure alpha and beta polymorphs of this polymer. The measurements were performed using cross-polarization and magic angle spinning (CP/MAS) techniques. Density functional theory gauge-including-atomic-orbital (DFT GIAO) calculations of NMR shielding parameters (13)C sigma(ii) were performed for the optimized geometry and structure of a xylylene trimer, acquired from the X-ray data, including intermolecular interactions. Two-dimensional phase adjusted spinning sideband (2D PASS) correlation was employed for the assignment of the values of the principal elements (13)C delta(ii) of the chemical shift tensor (CST). A comparative analysis of shielding (sigma(ii)) versus chemical shift (delta(ii)) parameters showed substantial differences between the molecular dynamics of alpha and beta polymorphs. This observation was further supported by the measurements of (13)C T(1) relaxation times and the analysis of cross-polarization kinetics. Frequency switched Lee-Goldburg heteronuclear correlation (FSLG HETCOR) for the (1)H-(13)C system was used in order to analyze molecular packing in both polymorphs. As a result of all of the above measurements, new insight into the mechanism of thermal phase transition from the alpha to the beta polymorph of poly(p-xylylene) is presented.

Distance measurements in disodium ATP hydrates by means of 31P double quantum two-dimensional solid-state NMR spectroscopy.

POST-C7 measurements provide constraints allowing distinguishing crystal lattice organization and establishing intra and/or intermolecular distances between phosphorus atoms of triphosphate chains for different hydrates of disodium ATP salts. Double-quantum efficiency in function of excitation time obtained from series of two-dimensional spectra for POST-C7 experiments was used to set up of buildup curves and semi-quantitative measure of 31P-31P length.

Coulometric titration of ketotifen in tablets.

A method for the determination of ketotifen involving its reaction with iodine in an alkaline medium is presented. In coulometric titration using biamperometric end-point detection 0.25-2 micromol (77-618 microg) of ketotifen was successfully determined. The elaborated method was applied to the determination of ketotifen in drugs.

Two-dimensional and variable temperature 31P solid-state NMR studies of single crystals containing symmetrical/unsymmetrical bis[6-O,6-O'-(1,2:3,4-diisopropylidene-alpha-D- galactopyranosyl)thiophosphoryl] dichalcogenides.

The organisation and phase transition of single crystals containing three isostructural bis[6-O,6-O'-(1,2:3,4-diisopropylidene-alpha- D-galactopyranosyl)thiophosphoryl] dichalcogenide derivatives: disulfide 1, diselenide 2 and mixed seleno-sulfide 3, was deduced upon 1D, 2D and variable temperature 31P NMR experiments.

Comparison of the thin-layer chromatographic properties of sulfur-containing amino acids and their aminophosphonic analogues.

The thin-layer chromatographic behavior of the natural, sulfur-containing amino acids (Cys, Hcys, Met) and their phosphonic analogues (CysP, HcysP, MetP) has been studied. Their detection limits using iodine and molybdate, ninhydrine and iodine-azide reagents were determined, and the R(F) values of these two classes of amino acids in acidic, neutral and mild basic solvent systems were compared.

Meter-dosed, inhaled beclomethasone initiated at birth to prevent bronchopulmonary dysplasia.

OBJECTIVE: To examine the hypothesis that meter-dosed, inhaled beclomethasone administered to premature infants, beginning at birth and continuing in a tapering dosage schedule over the first 12 days of life, decreases the occurrence of bronchopulmonary dysplasia (BPD), at 36 wks corrected gestational age. DESIGN: Prospective, randomized, double-blind, placebo-controlled, small pilot clinical trial. SETTING: Tertiary care, neonatal intensive care unit. PATIENTS: Premature low birth weight neonates (

Potentiometric and coulometric titration of 2-thiobarbituric acid.

A new method for the determination of 2-thiobarbituric acid, using its reaction with iodine in an alkaline medium is presented. In the volumetric titration with potentiometric end-point detection, the determinability range is 10-400 micromol (1.4-58 mg). In coulometric titration using the biamperometric end-point detection, 0.1-20 micromol (1.4 x 10(-2)-2.9 mg) of 2-thiobarbituric acid was successfully determined.

Organothiophosphorus compounds as inductors of the iodine-azide reaction. Analytical application.

Thiophosphoryl compounds were found to exhibit strong induction activity in the iodine-azide reaction. On this basis three procedures for their determination: titrimetric (0.15-1 mumol), coulometric (1-20 nmol) and spectrophotometric (0.5-5 nmol) have been developed. RSD in all applied methods (techniques) have been found at the 1-7% level. The induction coefficients were dependent on the type of compound applied and on the reaction condition and varied from 90 to 450.

Iodimetric determination of 2-mercaptopyrimidines.

A new method for the determination of 2-mercaptopyrimidines, using their reaction with iodine in neutral and alkaline medium, is presented. The determinability range in the volumetric titration, in phosphate buffer with starch as an indicator, was found to be equal to 40-1000 mumol for 2-mercaptopyrimidine (I) and 100-2000 mumol for 2-mercapto-4-methylpyrimidine (II), and 200-2000 mumol for 4,6-dimethyl-2-mercaptopyrimidine (III). In the volumetric titration in alkaline medium, with the potentiometric end-point detection, the determinability range is 50-250 mumol for 2-mercapto-4-methylpyrimidine (II), 50-500 mumol for 4,6-dimethyl-2-mercaptopyrimidine (III), 20-250 mumol for 4,5-diamino-2,6-dimercaptopyrimidine (IV), and 20-1000 mumol for 2-thioorotic acid (V). In the coulometric titration, using the biamperometric end-point detection, 0.1-4.0 mumol of 2-mercaptopyrimidine (I) and 0.1-5.0 mumol of 2-thioorotic acid (V) were successfully determined.

The trifluoroacetic anhydride-sodium iodide system as a reagent for determination and microdetermination of nitroxide radicals.

A trifluoroacetic anhydride-sodium iodide mixture (TFAA-I) reacts with nitroxide radicals with liberation of iodine. Since stoichiometric amounts of iodine are formed from nitroxides, the TFAA-I reagent can be applied to their analytical determination. Two procedures for the determination of nitroxides (titrimetric on mumol and spectrometric on nmol levels) are described.

Highly sensitive spectrophotometric microdetermination of sulphoxides.

The reaction of sulphoxides with trifluoroacetic anhydride and iodide in acetone medium to produce iodine, which can be used for their titrimetric determination, has been adapted for spectrophotometric determination of sub-mu mole amounts of sulphoxides.

A new method for the iodometric determination of sulphoxides.

A method is described for determination of sulphoxides through their reaction with iodide in a trifluoroacetic acid/acetone medium to produce iodine, which is then titrated with thiosulphate.

Pulsepolarographic determination of 6-benzyl-2-thio-uracil.

Polarographic (DPP) activity of 6-benzyl-2-thiouracil (6-benzyl-2-mercapto-4-pyrimidinol, BTU) has been examined in a wide range of pH values and it has been discovered that the number and the height of observed peaks depends on composition of supporting electrolyte and concentration of the thiol. Two different types of signals can be obtained. One of them is controlled by diffusion while the other by adsorption. The procedure for the determination of BTU in pure samples in 0.1 mol.dm-3 sodium hydroxide solution has been worked out. The measurements can be performed in a range 3.10(-4)-3.10(-3) mol.dm-3 of BTU. The detection limit is however lower and reaches 5.10(-6) mol.dm-3. The method has been used in the determination of BTU in an antithyroid drug Basdène.

High-resolution solid-state NMR spectroscopy as a tool for investigation of enantioselective inclusion complexation.

In this paper, we showed the application of solid state-NMR (SS NMR) spectroscopy in structural studies of chiral compounds employing sample of (E)-1-diphenylphosphinoylpent-3-en-2-ol 1 as a model compound. Racemate of 1 was fully characterized by NMR techniques (both in liquid and solid phase) and X-ray crystallography. Theoretical calculations employing the GIAO approach were used to explain the influence of hydrogen bonding on 31P NMR shielding parameter in racemate. Enantioselective inclusion complexation (EIC) method with TADDOL as host molecule was applied to separate of enantiomers. The formation of host-guest complex and decomplexation procedure was monitored by means of the SS NMR. The liquid-state NMR, due to similarity of 13C and 31P spectral parameters was not able to distinguish racemate from enantiomer. In the solid phase, owing to distinction of hydrogen bonding and molecular packing in the crystal lattice, racemate and enantiomers were easy recognized by NMR spectroscopy.

Potentiometric and coulometric titration of 6-propyl-2-thiouracil.

A method for the determination of 6-propyl-2-thiouracil involving its reaction with iodine in an alkaline medium is presented. In volumetric titration with potentiometric end-point detection, the range of determination is 125-500 mumol (21-85 mg). In coulometric titration using biamperometric end-point detection, 0.5-5.0 mumol (0.085-0.85 mg) of 6-propyl-2-thiouracil was successfully determined. The RSD in all applied techniques was < 1%. The methods developed were applied to the determination of 6-propyl-2-thiouracil in tablets.

Neutrophil-mediated phospholipid peroxidation assessed by gas chromatography-mass spectroscopy.

Disease pathophysiology frequently involves manifestations of the systemic inflammatory response syndrome. Oxyradicals represent key inflammatory mediators, and neutrophils are one important source of oxyradicals. This investigation examined neutrophil-mediated peroxidation of dilinoleoyl phosphatidyl-choline (DLPC) liposomes by monitoring the appearance of monohydroxyl linoleic acid with the use of gas chromatography-mass spectroscopy (GC-MS), compared with traditional assessment of thiobarbituric acid-reactive species (TBARS) and phosphatidylcholine-specific conjugated dienes. DLPC was peroxidized in a system using activated neutrophils in balanced salt solution containing chelated iron. 9-Monohydroxyl linoleic acid and 13-monohydroxyl linoleic acid were readily identified in neutrophil-mediated peroxidized DLPC with the use of GC-MS. Neutrophil NADPH oxidoreductase specific activity correlated highly with total ion current or specific ion monitoring of integrated peak areas for peroxidized linoleic acid but correlated poorly with DLPC-derived TBARS or conjugated dienes. These results ascertain that activated neutrophils mediate phosphatidylcholine lipid peroxidation to specific products, which may be precisely monitored with the use of GC-MS. The extent of this peroxidation is highly correlated with the magnitude of the neutrophil respiratory burst.

Bronchoalveolar oxyradical inflammatory elements herald bronchopulmonary dysplasia.

OBJECTIVES: To quantify oxyradical inflammatory markers in serial endotracheal tube aspirates obtained from premature neonates at risk for developing bronchopulmonary dysplasia, and to correlate these parameters with clinical manifestations of the disease. DESIGN: Prospective cohort study. SETTING: Tertiary neonatal intensive care unit. PATIENTS: Twenty-eight intubated, premature infants, with 15 infants displaying simple respiratory distress syndrome and 13 infants eventually developing bronchopulmonary dysplasia. INTERVENTIONS: Endotracheal tube aspirates were collected and clinical severity scores were calculated longitudinally from an inception cohort during the first week of life. Diagnosis of bronchopulmonary dysplasia by standard criteria was recorded at 30 days of life. Various biochemical analyses related to pulmonary oxyradical stress were determined on endotracheal tube aspirates and were normalized according to the magnitude of serum/aspirate urea ratios. The demographic, illness severity, and biochemical characteristics of infants with simple respiratory distress syndrome and those characteristics of infants developing bronchopulmonary dysplasia were evaluated by masked comparison. MEASUREMENTS AND MAIN RESULTS: Populations of respiratory distress syndrome and bronchopulmonary dysplasia infants could be differentiated during the first week of life by means of the following parameters: gestational age; birth weight; Score of Neonatal Acute Physiology; Neonatal Therapeutic Intervention Scoring System; epithelial lining fluid leukocytes; elastase; myeloperoxidase; xanthine oxidase and catalase enzyme activities; and total sulfhydryls. CONCLUSIONS: Infants with simple respiratory distress syndrome could be segregated from those infants who developed bronchopulmonary dysplasia by the magnitude of the epithelial lining fluid oxyradical inflammation markers. While infants developing bronchopulmonary dysplasia typically exhibited increased concentrations of these markers during the first week of life, those infants with simple respiratory distress syndrome displayed low, uniform, or decreasing values of these markers over this interval. Infants developing bronchopulmonary dysplasia demonstrate an early pulmonary inflammatory response, and one key aspect of this response involves various oxyradical-generating systems.

Okadaic acid induces dephosphorylation of histone H1 in metaphase-arrested HeLa cells.

It is shown here that treatment of metaphase-arrested HeLa cells with okadaic acid (0.15-2.5 microM) leads to dephosphorylation of histone H1. This effect is presumably due to the specific ability of okadaic acid to inhibit protein phosphatases 1 and/or 2A, because okadaic acid tetraacetate, which is not a phosphatase inhibitor, has no effect. Dephosphorylation of H1 does not occur if okadaic acid-treated cells are simultaneously treated with 20 nM calyculin A, or if the okadaic acid concentration is 5.0 microM or greater. The mechanism behind this phenomenon is not known. However, the results suggest that the chain of events leading to histone dephosphorylation may be negatively controlled by a protein phosphatase 2A, while the phosphatase which actually dephosphorylates H1 could be a protein phosphatase 1. It remains to be determined whether the phosphatase involved here is the same enzyme as that which dephosphorylates H1 at the end of normal mitosis.

Anisotropy of chemical shift and J coupling for P-31 and Se-77 in trimethyl and triphenyl phosphine selenides.

The 31P and 77Se magic angle spinning (MAS) nuclear magnetic resonance (NMR) experiments for selenium-77 enriched (70%) trimethylphosphine selenide 1 and triphenylphosphine selenide 2 were carried out in order to determine the nuclear magnetic shielding tensors of both nuclei and to establish values of the phosphorus-selenium indirect spin-spin coupling anisotropy delta J. The m = +1/2 and m = -1/2 subspectra were analysed by the dipolar-splitting-ratio method of Eichele and Wasylischen. For the C(S) molecule 1, delta J was obtained to be +640 +/- 260 Hz from the 31P spectrum and +550 +/- 140 Hz from the 77Se spectrum. Density functional theory (DFT) calculations give a delta J value of about +705 Hz. The value of delta J could not be determined unambiguously by analysis of the 31P spectra for the C1 molecules 2; nevertheless, an estimation of delta J was possible. The principal axis 3 of the phosphorus shielding tensor was determined to be nearly parallel to the PSe bond in 1 and 2. For the selenium shielding of 1, the same orientation was found, whereas in 2, the principal axis 2 of the selenium shielding was found to be oriented nearly along the PSe bond. The experimentally determined phosphorus nuclear magnetic shielding tensors agree well with those calculated by the IGLO method. For those two principal values of the selenium-shielding tensors corresponding to directions nearly perpendicular to the SeP bond, the agreement between calculated and experimental values is satisfactory. For the third one, corresponding to the principal axis close to the SeP bond, the calculated deshielding contributions are distinctly too small for both compounds investigated. Trends observed for the calculated molecular orbital (MO) contributions to the shielding as well as possible reasons for the underestimation of the deshielding contributions along the SeP bond are discussed.