Publications by authors named "Bui K"

The high rate of attrition during drug development and its associated high research and development (R&D) cost have put pressure on pharmaceutical companies to ensure that candidate drugs going to clinical testing have the appropriate quality such that the biological hypothesis could be evaluated. To help achieve this ambition, drug metabolism and pharmacokinetic (DMPK) science and increasing investment have been deployed earlier in the R&D process. To gain maximum return on investment, it is essential that DMPK concepts are both appropriately integrated into the compound design process and that compound selection is focused on accurate prediction of likely outcomes in patients.

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Malignant optic nerve glioma (MONG) is a rare but uniformly fatal disease that remains poorly understood. We describe a notable case of this rare disease occurring in the optic chiasm. Normal brain imaging and normal ophthalmic examination two years prior to diagnosis provide evidence for genesis of MONG in our patient.

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Although eukaryotic flagella and cilia all share the basic 9+2 microtubule-organization of their internal axonemes, and are capable of generating bending-motion, the waveforms, amplitudes, and velocities of the bending-motions are quite diverse. To explore the structural basis of this functional diversity of flagella and cilia, we here compare the axonemal structure of three different organisms with widely divergent bending-motions by electron cryo-tomography. We reconstruct the 3D structure of the axoneme of Tetrahymena cilia, and compare it with the axoneme of the flagellum of sea urchin sperm, as well as with the axoneme of Chlamydomonas flagella, which we analyzed previously.

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Unlabelled: Mucociliary clearance on the surface of the tracheal lumen is an important component of lung defense against dust mites and viruses. However, the axonemal structure that achieves effective ciliary motion, and the mechanisms by which discretely distributed ciliary cells generate directional flow are unknown. In this study, we examined individual ciliary motion with 7- to 9-nm spatial precision by labeling the ciliary tip with quantum dots and detected an asymmetric beating pattern.

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A novel series of piperazine derivatives exhibits sub-nanomolar binding and enhanced subtype selectivity as δ-opioid agonists. The synthesis and SAR are described as well as the application of computational models to improve in vitro ADME and safety properties suitable for CNS indications, specifically microsomal clearance, permeability, and hERG channel inhibition.

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A series of 4-piperidin-4-ylidenemethyl-benzamide δ-opioid receptor agonists is described with an emphasis on balancing the potency, subtype selectivity and in vitro ADME and safety properties. The three sites impacting SAR are substitutions on the aryl group (R(1)), the piperidine nitrogen (R(2)), and the amide (R(3)). Each region contributes to the balance of properties for δ opioid activity and a desirable CNS profile, and two clinical candidates (20 and 24) were advanced.

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Radial spokes (RSs) are ubiquitous components in the 9 + 2 axoneme thought to be mechanochemical transducers involved in local control of dynein-driven microtubule sliding. They are composed of >23 polypeptides, whose interactions and placement must be deciphered to understand RS function. In this paper, we show the detailed three-dimensional (3D) structure of RS in situ in Chlamydomonas reinhardtii flagella and Tetrahymena thermophila cilia that we obtained using cryoelectron tomography (cryo-ET).

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Ten oleanane-type saponins (1-10), including three new compounds, namely bifinosides A-C (1-3), were isolated from the roots of Panax bipinnatifidus SEEM. Their structures were elucidated on the basis of chemical and spectroscopic methods.

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Background: Several of the health benefits and risks associated with the combined oral contraceptive pill (COCP) are particularly relevant to women at risk of hereditary breast and/or ovarian cancer.

Methods: Eighty-three past female patients of an Australian hereditary cancer clinic aged 18-50 years completed a self-report questionnaire to assess their contraceptive practices, knowledge and information needs (44% response rate).

Results: Ninety-two percent of participants had previously used the COCP, with a mean knowledge score of 3.

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4-({4-[(2-hydroxy-ethyl)-methyl-carbamoyl]-phenyl}-quinolin-8-yl-methylene)-1-thiazol-4-ylmethyl-piperidinium (compound I) is a selective agonist of δ-opioid receptor developed for the treatment of depressive and anxiety disorders. The in vitro biotransformation studies using rat, dog, and human hepatocytes showed that the metabolites detected in human hepatocytes were also found in either rat or dog hepatocytes. M1 (N-dealkylation), M2 (N-demethylation), and M4 (carboxylic acid metabolite) were major phase I metabolites observed in all three species.

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Supernovae are stellar explosions driven by gravitational or thermonuclear energy that is observed as electromagnetic radiation emitted over weeks or more. In all known supernovae, this radiation comes from internal energy deposited in the outflowing ejecta by one or more of the following processes: radioactive decay of freshly synthesized elements (typically (56)Ni), the explosion shock in the envelope of a supergiant star, and interaction between the debris and slowly moving, hydrogen-rich circumstellar material. Here we report observations of a class of luminous supernovae whose properties cannot be explained by any of these processes.

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In the present article, we summarize the preclinical pharmacology of 4-{(R)-(3-aminophenyl)[4-(4-fluorobenzyl)-piperazin-1-yl]methyl}-N,N-diethylbenzamide (AZD2327), a highly potent and selective agonist of the δ-opioid receptor. AZD2327 binds with sub-nanomolar affinity to the human opioid receptor (K(i) = 0.49 and 0.

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Two new lignans, palatiferin A (1) and palatiferin B (2), were isolated from the roots of Pseuderanthemum palatiferum, together with five known triterpenes, epifriedelanol (3), lupeol (4), lupenone (5), betulin (6), pomolic acid (7), and a dipeptide asperglaucide (8). Their structures were established from 2D NMR and mass spectroscopy. The absolute configuration of 1 and 2 was proposed based on the comparison of their optical rotation activities with those of compounds with similar structures such as wodeshiol and paulownin.

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Unlabelled: The short-comings of current anticoagulants have led to the development of newer, albeit more expensive, oral alternatives.

Objective: To explore the potential impact the new anticoagulants dabigatran and rivaroxaban in the local hospital setting, in terms of utilisation and subsequent costing.

Method: A preliminary costing analysis was performed based on a prospective 2-week clinical audit (29th June - 13th July 2009).

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Electron cryo-tomography is a potential approach to analyzing the three-dimensional conformation of frozen hydrated biological macromolecules using electron microscopy. Since projections of each individual object illuminated from different orientations are merged, electron tomography is capable of structural analysis of such heterogeneous environments as in vivo or with polymorphism, although radiation damage and the missing wedge are severe problems. Here, recent results on the structure of eukaryotic flagella, which is an ATP-driven bending organelle, from green algae Chlamydomonas are presented.

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We determined the experimental solubility of CNS marketed drugs. Of the 98 drugs measured, greater than 90% had solubility >10 μM in pH 7.4 buffer.

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Summary Objectives: To explore the decision of induced abortion among HIV-positive women and examine how the decision is associated with socioeconomic characteristics and the availability of comprehensive programmes aiming at preventing mother to child transmission of HIV.

Methods: A descriptive cross-sectional study was conducted in two provinces of Northern Vietnam. In all 707 HIV-positive women were recruited through collaboration with commune health centres and peer groups.

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Lentiviral vectors with the firefly luciferase or enhanced green fluorescent protein (EGFP) transgenes were delivered to the amniotic fluid of murine fetuses at Embryonic Day (E) 14.5 or E16.5.

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Introduction: A novel automated blood sampling and telemetry (ABST) system was developed to integrate pharmacokinetic (PK), pharmacodynamic (PD) and toxicology studies. The goals of this investigation were to determine: 1) optimal feeding conditions and minimal acclimation times for recording PD parameters (blood pressure, heart rate, and temperature) after animals arrived on-site; 2) stress hormone levels in ABST-housed rats; 3) the feasibility of simultaneously recording cardiovascular parameters with electroencephalogram (EEG); 4) the equivalence of renal endpoints from ABST-housed rats with those in the metabolic cage, and 5) the cardiovascular responses to baclofen.

Methods: Body weight, blood pressure, temperature, stress biomarkers, urine chemistries, renal biomarkers and responses to vehicle or baclofen (10mg/kg) were compared in awake and freely moving rats housed in the ABST system, home cage (HC) or metabolic cage.

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Outer and inner dynein arms generate force for the flagellar/ciliary bending motion. Although nucleotide-induced structural change of dynein heavy chains (the ATP-driven motor) was proven in vitro, our lack of knowledge in situ has precluded an understanding of the bending mechanism. Here we reveal nucleotide-induced global structural changes of the outer and inner dynein arms of Chlamydomonas reinhardtii flagella in situ using electron cryotomography.

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Encountering an incidental tumor or tumor-like lesion during a routine magnetic resonance imaging (MRI) of the knee is not uncommon. By far, the majority of these lesions are benign and many of them have characteristic appearances on MRI to allow a confident diagnosis. The most common, and some less common, but important incidental lesions will be discussed including bone lesions (bone cysts, subchondral fractures, enchondromas, non-ossifying fibromas, "tug" lesions, osteochondromas, bone infarcts, and prominent red marrow) and soft tissue lesions (synovial hemangiomas, intracapsular chondromas, bursae, synovitis, soft-tissue cysts, hematomas, heterotopic ossification, vascular lesions and normal variants).

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Rationale: Studies have demonstrated that bone marrow-derived cells can be recruited to injured lungs through an unknown mechanism. We hypothesize that marrow progenitors are mobilized into the circulation of patients with cardiac and/or respiratory failure, and may then traffic to and incorporate into the sites of tissue injury.

Objectives: To determine whether progenitor populations are increased in the blood of patients with severe acute cardiorespiratory failure placed on extracorporeal membrane oxygenation (ECMO).

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Background: Time series gene expression data analysis is used widely to study the dynamics of various cell processes. Most of the time series data available today consist of few time points only, thus making the application of standard clustering techniques difficult.

Results: We developed two new algorithms that are capable of extracting biological patterns from short time point series gene expression data.

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