Background: Currently available treatment options for chronic hepatitis B (CHB) are not recommended for HBeAg-negative patients with a low viral load. These patients may however benefit from treatment by achieving a functional cure, defined by HBsAg-loss and undetectable HBV DNA. This study evaluated the long-term effect of combination treatment with peg-interferon-alpha-2a (peg-IFN) and adefovir or tenofovir compared to no treatment in these patients.
View Article and Find Full Text PDFPerceptual learning (PL), often characterized by improvements in perceptual performance with training that are specific to the stimulus conditions used during training, exemplifies experience-dependent cortical plasticity. An improved understanding of how neuromodulatory systems shape PL promises to provide new insights into the mechanisms of plasticity, and by extension how PL can be generated and applied most efficiently. Previous studies have reported enhanced PL in human subjects following administration of drugs that increase signaling through acetylcholine (ACh) receptors, and physiological evidence indicates that ACh sharpens neuronal selectivity, suggesting that this neuromodulator supports PL and its stimulus specificity.
View Article and Find Full Text PDFCombining peginterferon-alfa-2a (pegIFN) with a nucleotide analogue can result in higher rates of HBsAg loss than either therapy given alone. Here, we investigated the durability of the response to combination therapy in chronic hepatitis B (CHB) patients after 5 years of follow-up. In the initial study, 92 CHB patients (44 HBeAg-positive, 48 HBeAg-negative) with HBV DNA >100 000 c/mL (~20 000 IU/mL) and active hepatitis were treated for 48 weeks with pegIFN 180 μg/week and 10 mg adefovir dipivoxil daily.
View Article and Find Full Text PDFThe monoamine serotonin (5-hydroxytryptamine; 5-HT) has been described as a homeostatic regulator of lactation. Recently, our laboratory determined that 5-HT is involved in the regulation of calcium and glucose homeostasis during the transition period in rodents. More specifically, we demonstrate that 5-HT is responsible for calcium mobilization from bone and upregulation of hepatic gluconeogenic enzymes and mammary gland glucose transporters.
View Article and Find Full Text PDFP450-dependent biotransformations in Escherichia coli are attractive for the selective oxidation of organic molecules using mild and sustainable procedures. The overall efficiency of these processes, however, relies on how effectively the NAD(P)H cofactors derived from oxidation of the carbon source are utilized inside the cell to support the heterologous P450-catalyzed reaction. In this work, we investigate the use of metabolic and protein engineering to enhance the product-per-glucose yield (Y(PPG)) in whole-cell reactions involving a proficient NADPH-dependent P450 propane monooxygenase prepared by directed evolution [P450(PMO)R2; Fasan et al.
View Article and Find Full Text PDFStructural modifications of carbamoylmethylphosphine oxide (CPMO)-functionalized triphenoxymethane platforms are described, and the influence of these changes on the ability of the ligand to extract actinides from simulated acidic nuclear waste streams has been evaluated. The ligand system has been shown to have excellent binding efficiency and a selectivity for An(IV) in comparison to the a simple monomeric CMPO ligand under analogous conditions. Both the extraction efficiency and selectivity are strongly dependent on the flexibility and electronic properties of the ligating units in the triphenoxymethane construct.
View Article and Find Full Text PDFInspired by trinuclear Zn(II) sites in enzymatic systems, a ligand system containing three preorganized (2-pyridyl)methyl piperazine moieties anchored onto a rigid C3-symmetric triphenoxymethane platform has been developed for preorganizing three zinc ions into an environment conducive to intramolecular interaction. Zinc(II) binding by this ligand has been analyzed by means of potentiometric measurements in 50% (v/v) CH3CN-H2O solutions. Subsequently a C3-symmetric trinuclear Zn(II) hydroxide complex of the C3-symmetric ligand was synthesized and fully characterized using NMR spectroscopy and X-ray crystallography.
View Article and Find Full Text PDFCytochrome P450 BM-3 from Bacillus megaterium was engineered for enantioselective epoxidation of simple terminal alkenes. Screening saturation mutagenesis libraries, in which mutations were introduced in the active site of an engineered P450, followed by recombination of beneficial mutations generated two P450 BM-3 variants that convert a range of terminal alkenes to either (R)- or (S)-epoxide (up to 83 % ee) with high catalytic turnovers (up to 1370) and high epoxidation selectivities (up to 95 %). A biocatalytic system using E.
View Article and Find Full Text PDFSubstrate engineered, achiral carboxylic acid derivative was biohydroxylated with various mutants of cytochrome P450 BM-3 to give two out of the four possible diastereoisomers in high de and ee. The BM-3 mutants exhibit up to 9200 total turnovers for hydroxylation of the engineered substrate, which without the protecting group is not transformed by this enzyme.
View Article and Find Full Text PDFUltrasound-mediated intrafollicular injection and aspiration procedures were used to investigate the ability of the selective cyclooxygenase-2 inhibitor, NS-398, to inhibit intrafollicular PGE2 synthesis and suppress ovulation in dairy cattle. Follicular growth and timing of the preovulatory gonadotropin surge were synchronized in 55 Holstein cows and the position of the ovulatory follicle was determined by daily ultrasound scanning. Preovulatory follicular fluid was aspirated from the largest follicle in four animals at 0, 6, 12, 18, and 24 h after GnRH injection (n = 20).
View Article and Find Full Text PDFCytochrome P450 BM-3 from Bacillus megaterium was engineered using a combination of directed evolution and site-directed mutagenesis to hydroxylate linear alkanes regio- and enantioselectively using atmospheric dioxygen as an oxidant. BM-3 variant 9-10A-A328V hydroxylates octane at the 2-position to form S-2-octanol (40% ee). Another variant, 1-12G, also hydroxylates alkanes larger than hexane primarily at the 2-position but forms R-2-alcohols (40-55% ee).
View Article and Find Full Text PDFSynchronization of ovulation (Ovsynch) is an effective method for controlling time of first and subsequent AI in lactating dairy cows. However, validation of the original Ovsynch program did not include testing the optimal time to deliver the final treatment of GnRH. In Experiment 1, the effect of administering the final dose of GnRH on the same day as prostaglandin F2alpha (PGF2alpha) administration was tested.
View Article and Find Full Text PDFSynchronization of ovulation (Ovsynch) using GnRH and PGF2 alpha allows control of follicle growth, corpus luteum regression, and ovulation, but resulting pregnancy rates vary. This study examined whether presynchronization to allow initiation of Ovsynch during diestrus would improve pregnancy rates at timed artificial insemination (AI). Lactating dairy cows (n = 427), 69 to 75 d postpartum, were randomly assigned to two groups by parity.
View Article and Find Full Text PDFThe matrix metalloproteinases (MMPs) have been implicated in the ovulatory process, but the specific roles of individual MMPs are unclear. This study examined the effect of the preovulatory gonadotropin surge on localization and regulation of MMP-2, MMP-14, and tissue inhibitor of metalloproteinases-2 (TIMP-2) mRNA and MMP-2 and TIMP-2 activity in bovine preovulatory follicles and new corpora lutea (CL). Ovaries containing ovulatory follicles or new CL were collected at approximately 0, 6, 12, 18, 24, and 48 h (CL) after a GnRH-induced gonadotropin surge.
View Article and Find Full Text PDFThe serine proteinases, tissue-type (tPA) and urokinase (uPA) plasminogen activator, are implicated in the ovulatory processes via their ability to convert plasminogen to its active form, plasmin. One mechanism for regulation of plasmin-directed ovarian extracellular matrix remodelling during follicle rupture and corpus luteum formation is through inhibition of plasminogen activation by the plasminogen activator inhibitors (PAI-1 and PAI-2). The effect of the preovulatory gonadotrophin surge on the temporal and spatial regulation of expression of PAI-1 and PAI-2 mRNA and PAI activity in preovulatory bovine follicles and new corpora lutea collected at 0, 6, 12, 18, 24 and 48 h after a GnRH-induced gonadotrophin surge was examined.
View Article and Find Full Text PDFThis study examined the effect of the preovulatory gonadotropin surge on the temporal and spatial regulation of tissue plasminogen activator (tPA), urokinase plasminogen activator (uPA), and uPA receptor (uPAR) mRNA expression and tPA, uPA, and plasmin activity in bovine preovulatory follicles and new corpora lutea collected at approximately 0, 6, 12, 18, 24, and 48 h after a GnRH-induced gonadotropin surge. Messenger RNAs for tPA, uPA, and uPAR were increased in a temporally specific fashion within 24 h of the gonadotropin surge. Localization of tPA mRNA was primarily to the granulosal layer, whereas both uPA and uPAR mRNAs were detected in both the granulosal and thecal layers and adjacent ovarian stroma.
View Article and Find Full Text PDFA ligand system containing three preorganized carbamoylmethylphosphine oxide (CMPO) moieties anchored onto a rigid C(3)-symmetric triphenoxymethane platform has been developed for facile metal complexation and subsequent extraction from aqueous acidic nuclear waste streams. Intended to mimic the 3:1 CMPO-actinide stoichiometry of the extracted species in the TRUEX nuclear waste treatment process, the CMPO arms on this ligand are oriented such that all three CMPO moieties can cooperatively bind a metal ion. Extractions of simulated nuclear waste streams (10(-4) M metal in 1 M nitric acid) with solutions of this ligand in methylene chloride (10(-3) M) reveal a high affinity for the actinide thorium and a very low, but constant, affinity for the lanthanides across the series.
View Article and Find Full Text PDFIn higher education, increasing emphasis is being placed on the use of new technologies in the classroom. However, the emphasis needs to be placed on methods that truly enhance understanding and knowledge retention. Class discussions help students understand and retain information previously presented in lecture format.
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