Analysis of procainamide-derivatised heparan sulphate disaccharides in biological samples using hydrophilic interaction liquid chromatography mass spectrometry

Glycosaminoglycans (GAGs) are a family of linear heteropolysaccharides made up of repeating disaccharide units that are found on the surface and extracellular matrix of animal cells. They are known to play a critical role in a wide range of cellular processes including proliferation, differentiation and invasion. To elucidate the mechanism of action of these molecules, it is essential to quantify their disaccharide composition. Analytical methods that have been reported involve either chemical or enzymatic depolymerisation of GAGs followed by separation of non-derivatised (native) or derivatised disaccharide subunits and detection by either UV/fluorescence or MS. However, the measurement of these disaccharides is challenging due to their hydrophilic and labile nature. Here we report a pre-column LC-MS method for the quantification of GAG disaccharide subunits. Heparan sulphate (HS) was extracted from cell lines using a combination of molecular weight cutoff and anion exchange spin filters and digested using a mixture of heparinases I, II and III. The resulting subunits were derivatised with procainamide, separated using hydrophilic interaction liquid chromatography and detected using electrospray ionisation operated in positive ion mode. Eight HS disaccharides were separated and detected together with an internal standard. The limit of detection was found to be in the range 0.6–4.9 ng/mL. Analysis of HS extracted from all cell lines tested in this study revealed a significant variation in their composition with the most abundant disaccharide being the non-sulphated ∆UA–GlcNAc. Some structural functional relationships are discussed demonstrating the viability of the pre-column method for studying GAG biolog

Can quantification of Serum Glycans predict Pre-Eclampsia?

Objectives: To determine if concentrations of placental glycans and glycan components are altered in pre-eclamspia and to determine if serum levels can predict pre-eclampsia. Methods: Serum samples were collected from women in the third trimester of singleton pregnancy but before the onset of pre-eclampsia and also from women during unaffected pregnancies at the samegestational age. Tissues were collected from the basal plate of placentas collected at delivery following uncomplicated singleton pregnancy (term and preterm) and from pregnancies complicated by preeclampsia. Pre-eclampsia was diagnosed according to International Society for the Study of Hypertension in Pregnancy criteria. Glycan components were isolated using a combination of enzyme digestion, molecular weight filtration and ion exchange chromatography, and then derivatised prior to separation using hydrophilic interaction liquid chromatography. Components were detected using electrospray ionisation operated in positive ion mode with single ion monitoring. Results: Specific glycan components (designated glycan 1, 2 and 3) were significantly altered in the serum from women who went on to have preeclampsia compared to those who had an unaffected pregnancy. Interestingly, levels of the same biomarkers were also elevated in nulliparous versus multiparous pregnancy. Biomarkers were also significantly altered in placental tissues from pregnancies complicated by preeclampsia Conclusion: This study suggests that altered glycan levels may contribute to impaired placental development and that the glycome is a potential diagnostic target for pre-eclampsia, and possibly other disorders of pregnancy

Experimental violation of a spin-1 Bell inequality using maximally-entangled four-photon states

We demonstrate the first experimental violation of a spin-1 Bell inequality. The spin-1 inequality is a calculation based on the Clauser, Horne, Shimony and Holt formalism. For entangled spin-1 particles the maximum quantum mechanical prediction is 2.552 as opposed to a maximum of 2, predicted using local hidden variables. We obtained an experimental value of 2.27 $\pm 0.02$ using the four-photon state generated by pulsed, type-II, stimulated parametric down-conversion. This is a violation of the spin-1 Bell inequality by more than 13 standard deviations.Comment: 5 pages, 3 figures, Revtex4. Problem with figures resolve

Thyroid uptake studies in infectious hepatitis

Thyroid-function studies were done in 43 cases of infectious hepatitis with varying degree of liver damage as judged by serum bilirubin levels. A different pattern of thyroid uptakes was seen in patients with moderate liver damage and those with severe liver damage. A good correlation was observed between thyroid uptake and degree of liver damage

Diagnosis of hyperthyroidism by external liver counting : correlation between external scintillation counting of the liver and plasma protein-bound iodine<SUP>131</SUP>

External liver counting clearly distinguishes between euthyroid and hyperthyroid patients (t = 10.2); hyperthyroid and nontoxic goitre patients (t = 11.9). Individual values for these patients show a good separation between the groups. Correlation coefficient between liver counts and PBI131 in euthyroid and hyperthyroid patients was found to be 0.84 and correlation coefficient for hyperthyroid and nontoxic goitre patients was 0.76. The advantages of external liver counting as an alternative method to plasma PBI131 estimations are: (a) simplicity of the techniques; (b) no additional well scintillation assembly needed, and (c) no errors in results due to contamination of glassware, chemicals, etc(a) simplicity of the techniques; (b) no additional well scintillation assembly needed, and (c) no errors in results due to contamination of glassware, chemicals, et

Antigenic Diversity, Transmission Mechanisms, and the Evolution of Pathogens

Pathogens have evolved diverse strategies to maximize their transmission fitness. Here we investigate these strategies for directly transmitted pathogens using mathematical models of disease pathogenesis and transmission, modeling fitness as a function of within- and between-host pathogen dynamics. The within-host model includes realistic constraints on pathogen replication via resource depletion and cross-immunity between pathogen strains. We find three distinct types of infection emerge as maxima in the fitness landscape, each characterized by particular within-host dynamics, host population contact network structure, and transmission mode. These three infection types are associated with distinct non-overlapping ranges of levels of antigenic diversity, and well-defined patterns of within-host dynamics and between-host transmissibility. Fitness, quantified by the basic reproduction number, also falls within distinct ranges for each infection type. Every type is optimal for certain contact structures over a range of contact rates. Sexually transmitted infections and childhood diseases are identified as exemplar types for low and high contact rates, respectively. This work generates a plausible mechanistic hypothesis for the observed tradeoff between pathogen transmissibility and antigenic diversity, and shows how different classes of pathogens arise evolutionarily as fitness optima for different contact network structures and host contact rates

X-ray and UV spectroscopy of Galactic diffuse hot gas along the LMC X--3 sight line

We present Suzaku spectra of X-ray emission in the fields just off the LMC X-3 sight line. OVII, OVIII, and NeIX emission lines are clearly detected, suggesting the presence of an optically thin thermal plasma with an average temperature of 2.4E6. This temperature is significantly higher than that inferred from existing X-ray absorption line data obtained with Chandra grating observations of LMC X-3, strongly suggesting that the gas is not isothermal. We then jointly analyze these data to characterize the spatial and temperature distributions of the gas. Assuming a vertical exponential Galactic disk model, we estimate the gas temperature and density at the Galactic plane and their scale heights as 3.6(2.9, 4.7)E6 K and 1.4(0.3, 3.4)E-3 cm^{-3} and 1.4(0.2, 5.2) kpc and $2.8(1.0, 6.4)$ kpc, respectively. This characterization can account for all the \ovi line absorption, as observed in a FUSE spectrum of LMC X-3, but only predicts less than one tenth of the OVI line emission intensity typically detected at high Galactic latitudes. The bulk of the OVI emission most likely arises at interfaces between cool and hot gases.Comment: 10 pages, 7 figures, 3 tables, accepted for publication in ApJ, 200

Seismic evidence for a rapidly rotating core in a lower-giant-branch star observed with Kepler

Rotation is expected to have an important influence on the structure and the evolution of stars. However, the mechanisms of angular momentum transport in stars remain theoretically uncertain and very complex to take into account in stellar models. To achieve a better understanding of these processes, we desperately need observational constraints on the internal rotation of stars, which until very recently were restricted to the Sun. In this paper, we report the detection of mixed modes - i.e. modes that behave both as g modes in the core and as p modes in the envelope - in the spectrum of the early red giant KIC7341231, which was observed during one year with the Kepler spacecraft. By performing an analysis of the oscillation spectrum of the star, we show that its non-radial modes are clearly split by stellar rotation and we are able to determine precisely the rotational splittings of 18 modes. We then find a stellar model that reproduces very well the observed atmospheric and seismic properties of the star. We use this model to perform inversions of the internal rotation profile of the star, which enables us to show that the core of the star is rotating at least five times faster than the envelope. This will shed new light on the processes of transport of angular momentum in stars. In particular, this result can be used to place constraints on the angular momentum coupling between the core and the envelope of early red giants, which could help us discriminate between the theories that have been proposed over the last decades.Comment: Accepted in ApJ, 39 pages, 16 figure