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Trend Lines (trend + line)

Distribution by Scientific Domains

Medical Sciences	33%

Selected Abstracts

Peak width-mass correlation in CID MS/MS of isomeric oligosaccharides using traveling-wave ion mobility mass spectrometry

JOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 10 2009
Tohru Yamagaki
Abstract Isomeric oligosaccharides ,-cyclodextrin (,-CD), glucosyl-,CD (Glc1 -,CD) and maltosyl-,CD (Glc2 -,CD) were analyzed by traveling-wave ion mobility (twIM) mass spectrometry (MS). Their formation of multicharged multimers differed from each other. The ion mobility-mass spectrometry was useful in the self-assembling and complex formation analyses of CD isomers. The drift times of the isomers and their product ions with the same mass were almost the same in collision-induced dissociation (CID) MS/MS. In contrast, the ion mobility peak widths were sensitive to structural differences of the isomeric product ions. The twIM peak width (ms - µs) of the product ions [M , Glcn + H]+ (n = 0 , 6) of ,-CD correlated linearly with their masses (Da); the large and/or long chain product ions had wider peak widths, which were much wider than those from the general diffusion effect. This was a novel and useful ,trend line' to discriminate between the three isomers. Plots of [M , Glc2 , 6 + H]+ of Glc1 -,CD and [M , Glc3 , 6 + H]+ of Glc2 -,CD product ions' plots were on the same trend line as ,-CD. The plots of [M , Glc1 + H]+ of Glc1 -,CD and [M , Glc1, 2 + H]+ of Glc2 -,CD strayed from the ,-CD line; their peak widths were narrower than those of ,-CD. These results indicated that product ions from the chemical species of Glc1 -, CD and Glc2 -,CD retained their CD structure. Analyses of the IM peak widths enable us to elucidate the structures of the product ions. Copyright © 2009 John Wiley & Sons, Ltd. [source]

Determining the possible building blocks of the Earth and Mars

METEORITICS & PLANETARY SCIENCE, Issue 5 2004
Thomas H. Burbine
Only a very small percentage of the combinations match the oxygen isotopic composition, the assumed bulk FeO concentration, and the assumed Fe/Al weight ratio for the Earth. Since chondrites are enriched in silicon relative to estimates of the bulk Earth, none of the combinations fall near the terrestrial magmatic fractionation trend line in Mg/Si-Al/Si space. More combinations match the oxygen isotopic composition and the assumed bulk FeO concentration for Mars. These combinations fall near the trend for shergottite meteorites in Mg/Si-Al/Si space. One explanation for the difficulty in forming Earth out of known chondrites is that the Earth may be composed predominately of material that did not survive to the present day as meteorites. Another explanation could be that significant amounts of silicon are sequestered in the core and/or lower mantle of the Earth. [source]

Peak width-mass correlation in CID MS/MS of isomeric oligosaccharides using traveling-wave ion mobility mass spectrometry

Pharmacodynamics of Carvedilol in Conscious, Healthy Dogs

JOURNAL OF VETERINARY INTERNAL MEDICINE, Issue 2 2006
Sonya G. Gordon
The purpose of the study reported here was to determine the magnitude and duration of beta-blocking efficacy, determine an effective dose and dosing interval, and document safety and tolerability of carvedilol given orally in clinically normal dogs. Pharmacodynamic data were evaluated in conscious, unrestrained, healthy hound dogs at baseline and after long-term oral administration of carvedilol (1.5 mg/kg of body weight PO q12h for >5 days). At baseline, heart rate (HR) and blood pressure (BP) data were collected continuously for 24 hours, and complete echocardiography was performed. This protocol was repeated after long-term oral carvedilol administration. Additionally, isoproterenol was administered to evaluate the magnitude and duration of the nonselective beta-blocking efficacy of carvedilol. An isoproterenol challenge was performed 0.75, 1.5, 2.25, 4, 6, 12, and 24 hours after carvedilol administration, with echocardiography being performed once at 2 hours. Plasma samples were obtained prior to each challenge time point for determination of plasma carvedilol concentration. Time series regression analysis indicated no difference between baseline and carvedilol-induced HR or BP trend lines in 6 of 8 dogs. In 2 of 8 dogs, HR, after long-term carvedilol administration, was reduced. Carvedilol attenuated isoproterenol-induced changes in HR by 54,76% through 12 hours and by 30% at 24 hours. The BP changes were attenuated by 80,100% through 12 hours. These data suggest that carvedilol (1.5 mg/kg PO q12h) in healthy, conscious dogs confers nonselective beta blockade for 12 hours, with minimal effects on resting HR, BP, and echocardiographic variables. Additionally, the magnitude of beta blockade correlated strongly to peak plasma carvedilol concentration, suggesting that therapeutic drug monitoring may be clinically useful. [source]

Topical bovine thrombin: a 21-year review of topical bovine thrombin spontaneous case safety reports submitted to FDA's Adverse Event Reporting System

PHARMACOEPIDEMIOLOGY AND DRUG SAFETY, Issue 2 2010
John A. Clark MD
Abstract Purpose To review topical bovine thrombin spontaneous adverse event (AE) reports that were forwarded to the US Food and Drug Administration's (FDA) Adverse Event Reporting System (AERS) between January 1986 and December 2006. Methods Forty-one spontaneous AE reports were summarized for reported AE profile and chronological reporting patterns. Each AE report was adjudicated by a hematologist for the topical bovine thrombin product that was given and the AE(s) that were reported. AEs were grouped as allergic, coagulopathy/bleeding, and all other AEs combined. Grouped AE serial analyses were carried out using successive 3-year time increments between 1986 (the year an AE report was first noted for a bovine thrombin product) and 2006 (the first full year that was available at the time of initiation of the data summary). Main outcome measures The primary outcome measures were every 3-year trend lines for all-AE reports, all reporters, and topical bovine thrombin brand mentions for 2 AE groups of interest (allergic events and coagulopathy/bleeding events). Results The all-AE spontaneous reporter trend showed a downward appearance for AE reporting activity that started in 1995,1998 and continued through 2004,2006. The all-AE reports trend showed two potential safety signals that could be identified serially: (1) a prominent 1989,1991 peak that was attributable to allergic events (in particular, anaphylaxis), and (2) a small 1995,2000 broad peak that was attributable in part to coagulopathy/bleeding events. Allergic events were predominantly reported with products approved prior to 1995, were not temporally associated with prior medical literature case reports, and continued to be forwarded to the FDA at low levels up to the end of this study in 2006. Coagulopathy/bleeding events were reported only with products approved prior to 1995, were temporally associated with medical literature case reports, and were not forwarded to the FDA after 2000. Conclusions Overall, spontaneous AE reporting for topical bovine thrombin occurs at very low levels, and appears to have been decreasing since 1995. The serial reporting patterns for topical bovine thrombin are best explained as a strong safety signal for allergic events with ongoing, low level reporting, and a weak safety signal for coagulopathy/bleeding events that ceased on or before 2000. Although this descriptive trend analysis cannot measure associations or causation, the coagulopathy/bleeding signal may have been prompted by multiple, antecedent published case reports. The subsequent diminishment of signal attributed to thrombin likewise may coincide with lack of such reporting in larger follow-up clinical trials or, alternatively, in the introduction and growing market share of thrombin brands of greater purity. Currently marketed topical bovine thrombin formulations are rarely volunteered as possible causes of adverse events. Copyright © 2009 John Wiley & Sons, Ltd. [source]

Changes in zinc uptake in response to ascorbic acid and folic acid in rat liver slices under normal and oxidative stress conditions

BIOFACTORS, Issue 1 2007
R.S. Tupe
Abstract Zinc plays a dual role, as an integral part of metabolic machinery and in defense against reactive oxygen species. Hepatocytes are important sites for zinc metabolism for synthesis of zinc metalloproteins and maintaining its homeostasis. However, the factors influencing post absorptive zinc metabolism under normal and oxidative stress (OS) conditions are not well understood. Using rat liver slices, we conducted a series of four in vitro zinc uptake experiments to study influence of ascorbic acid and folic acid in normal and oxidative stress conditions with Zn concentrations representing deficient to excess states (7.7,30.7 millimole/L). Zinc uptakes under OS at these four zinc levels were lower than the normal conditions. Folic acid showed significant inhibitory effect on zinc uptake under both normal and OS conditions in a dose response manner. Nevertheless, dose response of ascorbic acid at four zinc levels indicated its marked enhancing effect under OS condition. Differences in zinc uptake trend lines between the normal and OS conditions for interaction of both the vitamins narrowed down as the zinc levels increased. Our results suggest that folic acid causes inhibitory effect, while ascorbic acid may be protective in OS with reference to zinc uptake. [source]