334 research outputs found
Metabolomics approach to studying minimally processed peach (Prunus persica) fruit
Fresh-cut fruit products for both retail and food service applications have increasingly appeared in the market place in recent years. Among different fruit types, peaches can be used and are highly appreciated as fresh-cut product although their commercial success is limited due to their short shelf-life and the quick onset of wounding-related physiological reactions. In this work we analyzed the technological and physiological changes induced by fresh-cut preparation in three different types of peach cultivars: 'Fayette' (melting), 'Wilhelmina' (non-melting) and 'Ghiaccio3' (stony hard). We performed a metabolite targeting profiling to focus on the changes in organic acid levels, important components of fruit taste and organoleptic quality of peaches. Interestingly, 'Ghiaccio3' showed an increase of several organic acids after cutting while 'Fayette' and 'Wilhelmina' showed unchanged amounts or a general reduction. Cutting induces a similar pattern of change in important metabolites (i.e., dehydroascorbate, alanine) in all the three peach types while other metabolites (i.e., citric acid) appeared to be differentially regulated in the considered peach cultivars
Effect of ethylene on postharvest strawberry fruit tissue biochemistry
The effect of continuous ethylene supplementation (50 µL L-1) on cold-stored strawberry fruit physiology and biochemistry, including phytohormone (abscisic acid) metabolism was investigated. In comparison with control fruit which exhibited high sucrose and malic acid contents during storage, ethylene-treated fruits showed increased respiration, sucrose hydrolysis and concomitant reducing sugars accumulation. Ethylene supplementation did not have any effect on phenolic profile. ABA biosynthesis, in both flesh and achenes, was promoted by ethylene. The results herein suggest that controlling ethylene after harvest could suppress senescence and extend shelf-life
Gabapentin Bioequivalence Study: Quantification By Liquid Chromatography Coupled To Mass Spectrometry
The study was performed to compare the bioavailability of two gabapentin 400 mg capsule formulation (Gabapentin from Arrow Farmacêutica S/A as test formulation and Neurontin ® from Pfizer, Brazil, as reference formulation) in 26 volunteers of both sexes. The study was conducted open with randomized two period crossover design and a one week wash out period. Plasma samples were obtained over a 48 hour interval. The gabapentin was analyzed by LC/MS/MS, in the presence of pracetamole as internal standard. With plasma concentration vs. time curves, data obtained from this metabolite, the following pharmacokinetics parameters were obtained: AUC 0-t, AUC 0-inf and C max. Geometric mean of gabapentin/Neurontin ® 400 mg individual percent ratio was 100.58% AUC 0-t, 101.35% for AUC 0-inf and 97.76% for C max. The 90% confidence intervals were 92.00 - 109.95%, 93.00 - 110.44%, 88.41 - 108.10%, respectively. Since the 90% confidence intervals for C max, AUC 0-t and AUC 0 -inf were within the 80 - 125% interval proposed by Food and Drug Administration, it was concluded that gabapentin 400 mg capsule was bioequivalent to Neurontin ® 400 mg capsule according to both the rate and extent of absorption. © 2011 Junior EA, et al.38187190Wattananat, T., Akarawut, W., Validated LC-MS-MS Method for the Determination of Gabapentin in Human Plasma: Application to a Bioequivalence Study (2009) J Chromatogr Sci, 47, pp. 868-871Stewart, B.H., Kagler, A.R., Thompson, P.R., Bockbrader, H.N., A saturable transport mechanism in the intestinal absorption of gabapentin is the underlying cause of the lack of proportionality between increasing dose and drug levels in plasma (1993) Pharma Res, 10, pp. 276-281McLean, M.J., Gabapentin in the management of convulsive disorders (1999) Epilepsia, 40, pp. 39-50Goa, K.L., Sorkin, E.M., Gabapentin: A review of its pharmacological properties and clinical potential in epilepsy (1993) Drugs, 46, pp. 409-427Zhu, Z., Neirinck, L., High-performance liquid chromatographic method for the determination of gabapentin in human plasma (2002) J Chromatogr B Analyt Technol Biomed Life Sci, 779, pp. 307-312Sagirli, O., Cetin, S.M., Determination of gabapentin in human plasma and urine by high-performance liquid chromatography with UV-vis detection (2006) J Pharm Biomed Anal, 42, pp. 618-624Jalalizadeh, H., Souri, E., Tehrani, M.B., Jahangiri, A., Validated HPLC method for the determination of gabapentin in human plasma using precolumn derivatization with 1-fluoro-2,4-dinitrobenzene and its application to a pharmacokinetic study (2007) J Chromatogr B Analyt Technol Biomed Life Sci, 854, pp. 43-47Forrest, G., Sills, G.J., Leach, J.P., Brodie, M.J., Determination of gabapentin in plasma by high-performance liquid chromatography (1996) J Chromatogr B Analyt Technol Biomed Life Sci, 681, pp. 421-425Tang, P.H., Miles, M.V., Glauser, T.A., Degrauw, T., Automated microanalysis of gabapentin in human serum by high-performance liquid chromatography with fluorometric detection (1999) J Chromatogr B Analyt Technol Biomed Life Sci, 727, pp. 125-129Hassan, E.M., Belal, F., Al-Deeb, O.A., Khalil, N.Y., Spectrofluorimetric determination of vigabatrin and gabapentin in dosage forms and spiked plasma samples through derivatization with 4-chloro-7-nitrobenzo-2-oxa-1,3-diazole (2001) J. AOAC Int., 84, pp. 1017-1024Gauthier, D., Gupta, R., Determination of gabapentin in plasma by liquid chromatography with fluorescence detection after solid-phase extraction with a C18 column (2002) Clin Chem, 48, pp. 2259-2261Chung, T.C., Tai, C.T., Wu, H.L., Simple and sensitive liquid chromatographic method with fluorimetric detection for the analysis of gabapentin in human plasma (2006) J Chromatogr A, 119, pp. 294-298Bahrami, G., Kiani, A., Sensitive high-performance liquid chromatographic quantitation of gabapentin in human serum using liquid-liquid extraction and pre-column derivatization with 9-fluorenylmethyl chloroformate (2006) J Chromatogr B Analyt Technol Biomed Life Sci, 835, pp. 123-126Krivanek, P., Koppatz, K., Turnheim, K., Simultaneous isocratic HPLC determination of vigabatrin and gabapentin in human plasma by dansyl derivatization (2003) Ther Drug Monit, 25, pp. 374-377Chang, S.Y., Wang, F.Y., Simple and sensitive liquid chromatographic method with fluorimetric detection for the analysis of gabapentin in human plasma (2004) J Chromatogr B Analyt Technol Biomed Life Sci, 799, pp. 265-270Wolf, C.E., Saady, J.J., Poklis, A., Determination of gabapentin in serum using solid phase extraction and gas-liquid chromatography (1996) J Anal Toxicol, 20, pp. 498-501Kushnir, M.M., Cossett, J., Brown, P.I., Urry, F.M., Analysis of gabapentin in serum and plasma by solid-phase extraction and gas chromatography-mass spectrometry for therapeutic drug monitoring (1999) J Anal Toxicol, 23, pp. 1-6Borrey, D.C., Godderis, K.O., Engelrelst, V.I., Bernard, D.R., Langlois, M.R., Quantitative determination of vigabatrin and gabapentin in human serum by gas chromatography-mass spectrometry (2005) Clin Chim Acta, 354, pp. 147-151Gambelunghe, C., Mariucci, G., Tantucci, M., Ambrosini, M.V., Gas chromatography-tandemmass spectrometry analysis of gabapentin in serum (2005) Biomed Chromatogr, 19, pp. 63-67Matar, K.M., Abdel-Hamid, M.E., Rapid tandem mass spectrometric method for determination of gabapentin in human plasma (2005) Chromatographia, 61, pp. 499-504Ramakrishna, N.V.S., Vishwottam, K.N., Koteshwara, M., Maroj, S., Santosh, M., Rapid quantification of gabapentin in human plasma by liquid chromatography/tandemmass spectrometry (2006) J Pharm Biomed Anal, 40, pp. 360-368Ifa, D.R., Falci, M., Moraes, M.E., Bezerra, F.A., Moraes, M.O., Gabapentin quantification in human plasma by high-performance liquid chromatography coupled to electrospray tandem mass spectrometry. Application to bioequivalence study (2001) J Mass Spectrom, 36, pp. 188-194Ji, H.Y., Jeong, D.W., Kim, Y.H., Kim, H.H., Yoon, Y.S., Determination of gabapentin in human plasma using hydrophilic interaction liquid chromatography with tandem mass spectrometry (2006) Rapid Commun Mass Spectrom, 20, pp. 2127-2132Carlsson, K.C., Reubsaet, J.L., Sample preparation and determination of gabapentin in venous and capillary blood using liquid chromatography-tandem mass spectrometry (2004) J Pharm Biomed Anal, 34, pp. 415-423Park, J.H., Jhee, O.H., Park, S.H., Lee, J.S., Lee, M.H., Validated LC-MS/ MS method for quantification of gabapentin in human plasma: Application to pharmacokinetic and bioequivalence studies in Korean volunteers (2007) Biomed Chromatogr, 21, pp. 829-83
Inflammatory angiogenesis as a target for prevention and therapy: Kaposi's sarcoma and HIV tat as models
252. Prediction of subject-specific SAR distribution in MSK MR exam at 7 T
Purpose
we predict SAR during MRI exam using a 7 T 1H 298 MHz eight-channel degenerate birdcage coil1 combining SAR simulations with subject-specific measured (RF) maps.
Materials and Methods
We simulated the coil1 in CST MW Suite, loaded by a model of human knee (Fig. 1, top). was calculated in an axial slice crossing the patella. The maximum local SAR for an Axial “Zero” Time-of-Echo (ZTE) sequence “SILENT”2 was calculated.
We acquired maps of an adult (female) knee with a Bloch-Siegert sequence on 7 axial slices, centered on the same slice of the simulation, on a GE MR950 7T human system. For each slice a coefficient C, proportional to avg, was used to scale the SAR simulated3.
Results
Fig. 1 shows: bottom left, simulated magnitude; bottom center, local SAR for an input of 1 W per channel; bottom right, simulated magnitude for a FA = 90° (length = 3.2 ms) sinc-pulse in the slice previously chosen.
Fig. 2 shows the subject-specific measured for a FA = 90° sinc-pulse. The predicted SAR obtained with scaled maps are 0.50 W/kg (global) and 3.68 W/kg (maximum).
Conclusions
we obtained a good agreement between simulated and measured in vivo maps, and we were able to calculate the distribution of SAR exposure, a safety MRI parameter not available in current exams, where only global SAR is provided, combining simulations and subject-specific measurements. Limits on global and local SAR (20 W/kg) were met for this sequence [1], [2], [3]
Deep learning-based parameter mapping for joint relaxation and diffusion tensor MR Fingerprinting
Magnetic Resonance Fingerprinting (MRF) enables the simultaneous
quantification of multiple properties of biological tissues. It relies on a
pseudo-random acquisition and the matching of acquired signal evolutions to a
precomputed dictionary. However, the dictionary is not scalable to
higher-parametric spaces, limiting MRF to the simultaneous mapping of only a
small number of parameters (proton density, T1 and T2 in general). Inspired by
diffusion-weighted SSFP imaging, we present a proof-of-concept of a novel MRF
sequence with embedded diffusion-encoding gradients along all three axes to
efficiently encode orientational diffusion and T1 and T2 relaxation. We take
advantage of a convolutional neural network (CNN) to reconstruct multiple
quantitative maps from this single, highly undersampled acquisition. We bypass
expensive dictionary matching by learning the implicit physical relationships
between the spatiotemporal MRF data and the T1, T2 and diffusion tensor
parameters. The predicted parameter maps and the derived scalar diffusion
metrics agree well with state-of-the-art reference protocols. Orientational
diffusion information is captured as seen from the estimated primary diffusion
directions. In addition to this, the joint acquisition and reconstruction
framework proves capable of preserving tissue abnormalities in multiple
sclerosis lesions
The impact of air pollution on hospital admissions: Evidence from Italy
In this paper we study the impact of air pollution on hospital admissions for chronic obstructive pulmonary disease for 103 Italian provinces, over the period from 2004 to 2009. We use information on annual mean concentrations of carbon monoxide, nitrogen dioxide, particulate matter, and ozone measured at monitoring station level to build province-level indicators of pollution. Hence, we estimate a regression model for hospital admissions, where we allow our aggregate measures of pollution to be subject to measurement error and correlated with the error term. We also adopt standard errors for estimates that are robust to serial and spatial correlation in the error term, to allow for temporal persistence and geographical concentration of unobservable risk factors.We find that higher levels of particulate matter are associated with higher levels of hospitalisation for children, while ozone plays an important role in explaining hospital admissions of the elderly. Other factors that appear to have an effect on hospital admissions for chronic obstructive pulmonary disease are precipitation and provincial unemployment rate
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