Deconjugation Kinetics of Glucuronidated Phase II Flavonoid Metabolites by B-glucuronidase from Neutrophils

Flavonoids are inactivated by phase II metabolism and occur in the body as glucuronides. Mammalian ß-glucuronidase released from neutrophils at inflammatory sites may be able to deconjugate and thus activate flavonoid glucuronides. We have studied deconjugation kinetics and pH optimum for four sources of ß-glucuronidase (human neutrophil, human recombinant, myeloid PLB-985 cells, Helix pomatia) with five flavonoid glucuronides (quercetin-3-glucuronide, quercetin-3'-glucuronide, quercetin-4'-glucuronide, quercetin-7-glucuronide, 3'-methylquercetin-3-glucuronide), 4-methylumbelliferyl-ß-D-glucuronide, and para-nitrophenol-glucuronide. All substrate-enzyme combinations tested exhibited first order kinetics. The optimum pH for hydrolysis was between 3.5-5, with appreciable hydrolysis activities up to pH 5.5. At pH 4, the Km ranged 44-fold from 22 µM for quercetin-4'-glucuronide with Helix pomatia ß-glucuronidase, to 981 µM for para-nitrophenol-glucuronide with recombinant ß-glucuronidase. Vmax (range: 0.735-24.012 µmol·min-1·unit-1 [1 unit is defined as the release of 1 µM 4-methylumbelliferyl-ß-D-glucuronide per min]) and the reaction rate constants at low substrate concentrations (k) (range: 0.002-0.062 min-1·(unit/L)-1 were similar for all substrates-enzyme combinations tested. In conclusion, we show that ß-glucuronidase from four different sources, including human neutrophils, is able to deconjugate flavonoid glucuronides and non-flavonoid substrates at fairly similar kinetic rates. At inflammatory sites in vivo the pH, neutrophil and flavonoid glucuronide concentrations seem favorable for deconjugation. However, it remains to be confirmed whether this is actually the case

The Smuggling Career of William King

This article discusses the activities of William King during the War of 1812. It describes that the war did not stop Anglo-American trade but forced it into semi-legal channels. The article was the 1977 Maine Historical Society Prize Essay

College Student Debt and Anticipated Repayment Difficulty

This study analyzes factors associated with anticipated difficulty with repayment of debt accumulated during college using a basic model of credit risk that includes socialization processes influencing college student financial decisions. The empirical analysis uses data from the 2010 Ohio Student Financial Wellness Study. Results provide evidence of male overconfidence in financial decision making, as males are less likely than females to predict repayment difficulties. Socialization process variables, including financial management practices, financial parenting communication, and expected economic returns from education, are strongly associated with anticipated debt repayment difficulty. Inclusion of these process variables in the model results in loss of explanatory power of many of the traditional individual success variables, such as grade point average, and graduation plans

The Ehingers and Welsers in Venezuela, 1520-1560

In South America, the territory which is now Venezuela, was granted to some German bankers whose representatives played a part in the conquest and exploration of that area. Most historians write with the assumption that the Germans played an unimportant role in South America, but this writer believes that they deserve more attention than is generally given to them. It is the purpose of this study to examine with some detail the activities of the Ehingers and Welsers in Venezuela. Comparatively little work has been done on this phase of South American history. Except for general histories, the writer was unable to find any works in English. The paucity of existing studies, the destruction of some records and the difficulty of obtaining existing material has necessarily limited this paper. It deals only with material printed in the English and German language and therefore is presented primarily from the German point of view. The only material used giving the Spanish side, is correspondence with members of the Spanish Embassy, the Consulates and the University of Venezuela. In scope the paper is limited to the activities of the Ehingers and Welsers in Venezuela during the period 1520 to 1560

Mutual information based clustering of market basket data for profiling users

Attraction and commercial success of web sites depend heavily on the additional values visitors may find. Here, individual, automatically obtained and maintained user profiles are the key for user satisfaction. This contribution shows for the example of a cooking information site how user profiles might be obtained using category information provided by cooking recipes. It is shown that metrical distance functions and standard clustering procedures lead to erroneous results. Instead, we propose a new mutual information based clustering approach and outline its implications for the example of user profiling

School for Charm (February 26, 1937)

Event program for School for Charm (February 26, 1937)

Reassessing evidence of Moon–Earth dynamics from tidal bundles at 3.2 Ga (Moodies Group, Barberton Greenstone Belt, South Africa)

Past orbital parameters of the Moon are difficult to reconstruct from geological records because relevant data sets of tidal strata are scarce or incomplete. The sole Archean data point is from the Moodies Group (ca 3.22 Ga) of the Barberton Greenstone Belt, South Africa. From the time-series analysis of tidal bundles from a well-exposed subaqueous sand wave of this unit, Eriksson and Simpson (Geology, 28, 831) suggested that the Moon’s anomalistic month at 3.2 Ga was closer to 20 days than the present 27.5 days. This is in apparent accordance with models of orbital mechanics which place the Archean Moon in a closer orbit with a shorter period, resulting in stronger tidal action. Although this study’s detailed geological mapping and section measuring of the site confirmed that the sandstone bed in question is likely a migrating dune, the presence of angular mud clasts, channel-margin slumps, laterally aggrading channel fills and bidirectional paleocurrents in overlying and underlying beds suggests that this bedform was likely located in a nearshore channel near lower-intertidal flats and subtidal estuarine bars; it thus carries risk of incomplete preservation. Repeated measurements of foreset thicknesses along the published traverse, measured perpendicular to bedding, failed to show consistent spectral peaks. Larger data sets acquired along traverses measured parallel to bedding along the 20.5 m wide exposure are affected by minor faulting, uneven outcrop weathering, changing illumination, weather, observer bias and show a low reproducibility. The most robust measurements herein confirm the periodicity peak of approximately 14 in the original data of Eriksson and Simpson (Geology, 28, 831). Because laminae may have been eroded, the measurements may represent a lower bound of about 28 lunar days per synodic month. This estimate agrees well with Earth–Moon dynamic models which consider the conservation of angular momentum and place the Archaean Moon in a lower orbit around a faster-spinning Earth