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Conversion of non-neuronal cells to neurons is a promising potential strategy for the treatment of neurodegenerative diseases. Recent studies have reported that shRNA-, CasRx-, or ASO-mediated Ptbp1 suppression could reprogram resident astrocytes to neurons. However, some groups have disputed the data interpretation of the reported neuron conversion events. These controversies surrounding neuron conversion may due to differences in the astrocyte fate-mapping systems. Here, we suppressed Ptbp1 using Cas13X, and labeled astrocytes with the HA tag fused to Cas13X (Cas13X-NLS-HA). Compared with the GFAP-driven tdTomato labeling system (AAV-GFAP::tdTomato-WPRE) in previous studies, we found no astrocyte-to-neuron conversion in mouse striatum via the HA-tagged labeling system. Our findings indicate Ptbp1 knockdown failed to induce neuron conversion in vivo.

Conversion of astrocytes to neurons (AtN) is a promising potential strategy for the treatment of neurodegenerative diseases. Recent studies have reported that shRNA-, CasRx-, or ASO-mediated Ptbp1 suppression could reprogram resident astrocytes to neurons1–3. However, some groups have disputed the data interpretation of the reported AtN conversion events4–7. These controversies surrounding AtN conversion may due to differences in the astrocyte fate-mapping systems they applied from that in the original study, i.e., recombinant mouse strains with astrocyte specific reporter constructs versus AAV-based labeling systems. Here, we applied AAV-based tracing systems to label astrocytes with GFAP-driven HA-tagged Cas13X (AAV-GFAP::Cas13X-NLS-HA-sgPtbp1). Compared to GFAP-driven tdTomato reporter (AAV-GFAP::tdTomato) system in previous studies, we found no AtN conversion in mouse striatum. Furthermore, no intermediate neurons and no neuron density increase suggested no AtN conversion. Our findings indicated that inconsistent AtN outcomes may arise from different fate-mapping systems between AAV and transgenic mice, as well as through use of different reporter proteins. Thus, the complexity of astrocyte labeling systems warrants careful attention when drawing conclusions about whether AtN conversion occurs.

Purpose Examine the feasibility of characterizing the regulation of renal oxygenation using high-temporal-resolution monitoring of the T 2 ∗ response to a step-like oxygenation stimulus. Methods For T 2 ∗ mapping, multi-echo gradient-echo imaging was used (temporal resolution = 9 seconds). A step-like renal oxygenation challenge was applied involving sequential exposure to hyperoxia (100% O2 ), hypoxia (10% O2 + 90% N2 ), and hyperoxia (100% O2 ). In vivo experiments were performed in healthy rats (N = 10) and in rats with bilateral ischemia-reperfusion injury (N = 4). To assess the step response of renal oxygenation, a second-order exponential model was used (model parameters: amplitude [A], time delay [Δt], damping constant [D], and period of the oscillation [T]) for renal cortex, outer stripe of the outer medulla, inner stripe of the outer medulla, and inner medulla. Results The second-order exponential model permitted us to model the exponential T 2 ∗ recovery and the superimposed T 2 ∗ oscillation following renal oxygenation stimulus. The in vivo experiments revealed a difference in Douter medulla between healthy controls (D 1, reflecting aperiodic recovery). The increase in Douter medulla by a factor of 3.7 (outer stripe of the outer medulla) and 10.0 (inner stripe of the outer medulla) suggests that this parameter might be rather sensitive to (patho)physiological oxygenation changes. Conclusion This study demonstrates the feasibility of monitoring the dynamic oxygenation response of renal tissues to a step-like oxygenation challenge using high-temporal-resolution T 2 ∗ mapping. Our results suggest that the implemented system analysis approach may help to unlock questions regarding regulation of renal oxygenation, with the ultimate goal of providing imaging means for diagnostics and therapy of renal diseases.

BACKGROUND Non-Gaussian diffusion models and T1 rho quantification may reflect the changes in tissue heterogeneity in hepatic sinusoidal obstruction syndrome (SOS). PURPOSE To investigate the feasibility of diffusion kurtosis imaging (DKI), stretched exponential model (SEM), and T1 rho quantification in detecting and staging SOS in a monocrotaline (MCT)-induced rat model. STUDY TYPE Animal study. POPULATION Thirty male Sprague-Dawley rats gavaged with MCT to induce hepatic SOS and six male rats without any intervention. FIELD STRENGTH/SEQUENCE 3.0T, DWI with five b-values (0-2000 s/mm2 ) and T1 rho with five spin lock times (1-60 msec). ASSESSMENT MRI was performed 1 day before and 1, 3, 5, 7, and 10 days after MCT administration. The corrected apparent diffusion coefficient (Dapp ), kurtosis coefficient (Kapp ), distributed diffusion coefficient (DDC), and intravoxel water molecular diffusion heterogeneity (α) were calculated from the corresponding non-Gaussian diffusion model. The T1 rho value was calculated using a monoexponential model. Specimens obtained from the six timepoints were categorized into normal liver (n = 6), early-stage (n = 16), and late-stage (n = 14) SOS in accordance with the pathological score. STATISTICAL TESTS Parametric statistical methods and receiver operating characteristic (ROC) curves were employed to determine diagnostic accuracy. RESULTS The Dapp , Kapp , DDC, α, and T1 rho values were correlated with pathological score with r values of -0.821, 0.726, -0.828, -0.739, and 0.714 (all P

Examine the feasibility of characterizing the regulation of renal oxygenation using high-temporal-resolution monitoring of theForThe second-order exponential model permitted us to model the exponentialThis study demonstrates the feasibility of monitoring the dynamic oxygenation response of renal tissues to a step-like oxygenation challenge using high-temporal-resolution

Non-Gaussian diffusion models and TTo investigate the feasibility of diffusion kurtosis imaging (DKI), stretched exponential model (SEM), and TAnimal study.Thirty male Sprague-Dawley rats gavaged with MCT to induce hepatic SOS and six male rats without any intervention.3.0T, DWI with five b-values (0-2000 s/mmMRI was performed 1 day before and 1, 3, 5, 7, and 10 days after MCT administration. The corrected apparent diffusion coefficient (DParametric statistical methods and receiver operating characteristic (ROC) curves were employed to determine diagnostic accuracy.The DDKI, SEM, and T2 TECHNICAL EFFICACY STAGE: 2 J. Magn. Reson. Imaging 2020;52:1110-1121.

Intermediates generated from three-component [3+2] cycloaddition of 2-bromobenzaldehydes and maleimides with amino esters or amino acids underwent N-propargylation and reductive Heck cyclization to form pyrrolidinedione-fused hexahydropyrrolo[2,1-a]isoquinolines.

It has been reported that quercetin is an activator of rat vitamin D receptor (rVDR). However, the conclusion was based on experiments performed without all the appropriate control groups, raising the possibility of a false-positive finding. Furthermore, distinct differences exist in the chemical structures of quercetin and 1α,25-dihydroxyvitamin D3, which is a prototypic agonist of VDR. Therefore, we investigated systematically whether quercetin and other flavonols are agonists of rVDR, mouse VDR (mVDR), or human VDR (hVDR). Quercetin, 3-hydroxyflavone, galangin, datiscetin, kaempferol, morin, isorhamnetin, tamarixetin, myricetin, and syringetin did not activate rVDR, mVDR, or hVDR in HEK-293 and HepG2 cells transfected with the corresponding receptor expression plasmid and either the secreted phosphoprotein 1 (Spp1) or cytochrome P450 24A1 (CYP24A1) reporter plasmid, when compared to the respective empty vector control group transfected with one or the other reporter plasmid and treated with one of the flavonols. Control analysis indicated that lithocholic acid and 1α,25-dihydroxyvitamin D3, but not rifampicin, activated rVDR, mVDR, and hVDR. As shown in transfected HEK293 and HepG2 cells, the flavonols did not influence hVDR ligand binding domain transactivation, steroid receptor coactivator-1 recruitment, or hVDR target gene expression (transient receptor potential cation channel 6 and CYP24A1) in hVDR-expressing Caco-2 or LS180 cells. The cumulative data from the cell-based experiments were corroborated by results obtained from molecular docking analysis. In conclusion, quercetin, 3-hydroxyflavone, galangin, datiscetin, kaempferol, morin, isorhamnetin, tamarixetin, myricetin, and syringetin are not agonists of rVDR, mVDR, or hVDR, as judged by cell-based and in silico evidence.

Air core solenoids are widely used in spherical tokamaks (STs), since their central stacks are quite compact and difficult to insert iron cores. However, much higher current are required to generate the same amount of flux in the solenoids with air core than in the ones with iron cores. Therefore, the power supplies of ohmic fields in STs are more challenging than those in conventional tokamaks with similar size. In this paper, a power supply based on insulated gate bipolar transistors (IGBTs) for the ohmic field coils in the Sino-UNIted Spherical Tokamak (SUNIST) is described. This power supply utilizes a modified H-bridge circuit, in which the high current switches are made by 10 IGBTs (rating 3.3 kV/1.2 kA) connected in parallel. A high voltage capacitor bank (1.2 kV/60 mF) and a low voltage capacitor bank (600 V/500 mF) store the energy required in different discharging stages. An adjustable low inductance high power resistor (0–0.3 Ω) made by stainless steel foils is used to help the circuit to generate a high current derivative in the ohmic field coils, which are required for gas breakdown, plasma current initiation and ramp up. The small loop voltage required for maintaining the plasma current is realized by the low voltage capacitor bank. For each tokamak discharge, all the switches of this power supply only need to be switched on and off one time with an interval of several milliseconds. Such slow operations of the IGBTs lower the risk of failure and minimize the technical difficulties of dynamical current sharing. The power supply is compact and reliable, and has discharged for more than 5000 times successfully.

Ethnopharmacological relevance Ginkgo biloba, which is one of the most frequently used herbal medicines, is commonly used in the management of several conditions, including memory impairment. Previously, it was reported to decrease the expression of peripheral benzodiazepine receptor and the biosynthesis of glucocorticoids, thereby regulating glucocorticoid levels. However, it is not known whether Ginkgo biloba extract regulates the function of the glucocorticoid receptor. Aim of the study We determined whether Ginkgo biloba extract and several of its chemical constituents affect the activity of human glucocorticoid receptor (hGR). Materials and methods A hGR-dependent reporter gene assay was conducted in HepG2 human hepatocellular carcinoma cells and hGR target gene expression assays were performed in primary cultures of human hepatocytes. Results Multiple lots and concentrations of the extract and several of its chemical constituents (ginkgolide A, ginkgolide B, ginkgolide C, ginkgolide J, and bilobalide) did not increase hGR activity, as assessed by a cell-based luciferase reporter gene assay. The extract did not influence the expression of hGR target genes, including tyrosine aminotransferase (hTAT), constitutive androstane receptor (hCAR), or pregnane X receptor (hPXR), in primary cultures of human hepatocytes. Moreover, hGR antagonism by mifepristone (also known as RU486) did not attenuate the extent of induction of hCAR- and hPXR-regulated target genes CYP2B6 and CYP3A4 by Ginkgo biloba extract. Conclusion Ginkgo biloba extract, ginkgolide A, ginkgolide B, ginkgolide C, ginkgolide J, and bilobalide are not activators of hGR. Furthermore, the extract does not influence the hGR-hCAR or the hGR-hPXR signaling pathway in primary cultures of human hepatocytes.

Administration of melatonin to rodents decreases the incidence of tumorigenesis initiated by benzo[a]pyrene or 7,12-dimethylbenz[a]anthracene, which requires bioactivation by cytochrome P450 enzymes, such as CYP1A1, CYP1A2 and CYP1B1, to produce carcinogenic metabolites. The present study tested the hypothesis that melatonin is a modulator of human CYP1 catalytic activity and gene expression. As a comparison, we also investigated the effect of melatonin on the catalytic activity of CYP2A6, which is also a procarcinogen-bioactivating enzyme. Melatonin (3-300 microm) decreased 7-ethoxyresorufin O-dealkylation catalyzed by human hepatic microsomes and recombinant CYP1A1, CYP1A2 and CYP1B1, whereas it did not affect coumarin 7-hydroxylation catalyzed by hepatic microsomes or recombinant CYP2A6. Melatonin inhibited CYP1 enzymes by mixed inhibition, with apparent K(i) values (mean +/- S.E.M.) of 59 +/- 1 (CYP1A1), 12 +/- 1 (CYP1A2), 14 +/- 2 (CYP1B1) and 46 +/- 8 microm (hepatic microsomes). Additional experiments indicated that melatonin decreased benzo[a]pyrene hydroxylation catalyzed by hepatic microsomes and CYP1A2 but not by CYP1A1 or CYP1B1. Treatment of MCF-10A human mammary epithelial cells with melatonin (up to 300 microm) did not affect basal or benzo[a]pyrene-inducible CYP1A1 or CYP1B1 gene expression. Consistent with this finding, melatonin did not influence reporter activity in aryl hydrocarbon receptor-dependent pGudluc6.1-transfected MCF-10A cells treated with or without benzo[a]pyrene, as assessed in an in vitro cell-based luciferase reporter gene assay. Overall, melatonin is an in vitro inhibitor of human CYP1 catalytic activity, and it may be useful to develop potent analogues of melatonin as potential cancer chemopreventive agents that block CYP1-mediated chemical carcinogenesis.

Type IV pili are extracellular polymers of the major pilin subunit. These subunits are held together in the pilus filament by hydrophobic interactions among their N-terminal α-helices, which also anchor the pilin subunits in the inner membrane prior to pilus assembly. Type IV pilus assembly involves a conserved group of proteins that span the envelope of Gram-negative bacteria. Among these is a set of minor pilins, so named because they share their hydrophobic N-terminal polymerization/membrane anchor segment with the major pilins but are much less abundant. Minor pilins influence pilus assembly and retraction, but their precise functions are not well defined. The Type IV pilus systems of enterotoxigenic Escherichia coli and Vibrio cholerae are among the simplest of Type IV pilus systems and possess only a single minor pilin. Here we show that the enterotoxigenic E. coli minor pilins CofB and LngB are required for assembly of their respective Type IV pili, CFA/III and Longus. Low levels of the minor pilins are optimal for pilus assembly, and CofB can be detected in the pilus fraction. We solved the 2.0 A crystal structure of N-terminally truncated CofB, revealing a pilin-like protein with an extended C-terminal region composed of two discrete domains connected by flexible linkers. The C-terminal region is required for CofB to initiate pilus assembly. We propose a model for CofB-initiated pilus assembly with implications for understanding filament growth in more complex Type IV pilus systems as well as the related Type II secretion system.

Danofloxacin was administered to 15 laying hens via drinking water for 12 days. Egg white and yolk from each egg were separated and danofloxacin residues were analysed by a high performance liquid chromatography method with fluorescence detection. Danofloxacin was detectable on the first day in egg white and on the second day in egg yolk after the beginning of administration, and higher danofloxacin residues accumulated in egg yolk than in egg white. Danofloxacin in egg white decreased fairly rapidly and was detectable up to 4 days after withdrawal of the drug. In egg yolk the residues declined slowly and were detectable up to 11 days after withdrawal of the drug.

A liquid chromatographic (LC) method with fluorescence detection was developed for determination of nine fluoroquinolones (FQs) in egg white and yolk. Egg white samples were deproteinized with acidified ethanol (egg yolk samples with acetonitrile and acidified ethanol), followed by defatting with hexane once (white) or twice (yolk), and extracting FQs into acetonitrile. After acetonitrile was evaporated, the residue was dissolved in mobile phase, and FQs were detected in LC with a fluorescence detector. Recoveries for nine FQs from white and yolk were 74.7–85.6%, 79.1–91.2%, respectively, with excellent relative standard deviations. The limits of quantification were 5–20 ng g−1.

Endometriosis is characterized by the presence of endometrial glands and stroma in extrauterine sites. Our objective was to determine whether endometriotic lesions (ELs) from women with endometriosis have altered retinoid levels compared with their eutopic endometrium, and to test the hypothesis that defects in all-trans retinoic acid (ATRA) biosynthesis in EL is related to reduced expression of cellular retinol-binding protein type 1 (RBP1). Retinoids were evaluated by liquid chromatography-tandem mass spectrometry and high-performance liquid chromatography in eutopic endometrial biopsies (EBs) and ELs from 42 patients with pathologically confirmed endometriosis. The ATRA levels were reduced, whereas the retinol and retinyl ester concentrations were elevated in EL compared with EB tissue. Similar results were found in a mouse model of endometriosis that used green fluorescent protein-positive endometrial tissue injected into the peritoneum of syngeneic hosts to mimic retrograde menses. The ATRA biosynthesis in vitro in retinol-treated primary human endometrial stromal cell (ESC) cultures derived from ELs was reduced compared with that of ESCs derived from patient-matched EBs. Correspondingly, RBP1 expression was reduced in tissue and ESCs derived from EL versus EB. Rbp1−/− mice showed reduced endometrial ATRA concentrations compared with wild type, associated with loss of tissue organization and hypercellularity. These findings provide the first quantitative measurements of ATRA in human endometrium and endometriosis, demonstrating reduced ATRA in ectopic tissue and corresponding ESC cultures. Quantitation of retinoids in murine endometriosis and in Rbp1−/− mice supports the contention that impaired ATRA synthesis caused by reduced RBP1 promotes an “endometriosis phenotype” that enables cells to implant and grow at ectopic sites.

Endometriosis is characterized by the presence of endometrial glands and stroma in extrauterine sites. Our objective was to determine whether endometriotic lesions (ELs) from women with endometriosis have altered retinoid levels compared with their eutopic endometrium, and to test the hypothesis that defects in all-trans retinoic acid (ATRA) biosynthesis in EL is related to reduced expression of cellular retinol-binding protein type 1 (RBP1). Retinoids were evaluated by liquid chromatography-tandem mass spectrometry and high-performance liquid chromatography in eutopic endometrial biopsies (EBs) and ELs from 42 patients with pathologically confirmed endometriosis. The ATRA levels were reduced, whereas the retinol and retinyl ester concentrations were elevated in EL compared with EB tissue. Similar results were found in a mouse model of endometriosis that used green fluorescent protein-positive endometrial tissue injected into the peritoneum of syngeneic hosts to mimic retrograde menses. The ATRA biosynthesis in vitro in retinol-treated primary human endometrial stromal cell (ESC) cultures derived from ELs was reduced compared with that of ESCs derived from patient-matched EBs. Correspondingly, RBP1 expression was reduced in tissue and ESCs derived from EL versus EB. Rbp1(-/-) mice showed reduced endometrial ATRA concentrations compared with wild type, associated with loss of tissue organization and hypercellularity. These findings provide the first quantitative measurements of ATRA in human endometrium and endometriosis, demonstrating reduced ATRA in ectopic tissue and corresponding ESC cultures. Quantitation of retinoids in murine endometriosis and in Rbp1(-/-) mice supports the contention that impaired ATRA synthesis caused by reduced RBP1 promotes an "endometriosis phenotype" that enables cells to implant and grow at ectopic sites.

A flame aerosol reactor was used to synthesize Fe(III)-doped titania powders. The processing conditions were controlled to obtain varying ratios of Fe:Ti in the as processed powders. The iron was incorporated into the titania lattice and promoted the conversion of the anatase to the rutile phase. With an increase in the iron dopant concentration, a decrease in the crystal size of the resultant titania particles was observed, along with a conversion to the amorphous state. The defect structure was further explored by Raman spectroscopy, revealing an increased shift and broadening of the anatase peaks with an increasing iron dopant concentration, and was attributed to shrinkage in the grain size. Absorption spectra revealed a shift of the absorption band toward the visible frequencies. Powders with Fe:Ti ratio exceeding 0.8 resulted in a binary mixture that had superparamagnetic characteristics.

A premixed flame aerosol reactor was used to produce titania particles by oxidation of titanium isopropoxide vapor. The growth, aggregation of particles, and the agglomerate structure were determined as a function of height in the flame using in situ light scattering and transmission electron microscopy (TEM) measurements. A methodology to determine the sintering characteristic time using light scattering data was established. The light scattering data provided the evolution of the fractal dimension which was then related to the normalized surface area change using a computer simulation. The sintering equation was redeveloped in terms of the normalized surface area, thus not having to account for coagulation effects. Experimental results indicate that isolated titania particles were observed at the high temperatures due to fast sintering. An agglomerate was obtained at downstream locations with an associated change in fractal dimension due to sintering.

Flame aerosol reactors are a route for large scale processing of nanostructured materials. However, fundamentals about processing-structure-property relationships have not been extensively researched. This work utilized three different burners to obtain a wide range of flame processing conditions (different time-temperature histories) to study the formation of nanophase titania particles. At low precursor reaction temperatures of about 400 °C, amorphous titania was obtained. At intermediate temperatures of 900 ~ 1430 °C, mixtures of anatase and rutile phase titania were obtained. At high temperatures of 1500 ~ 1570 °C, spherical particles of 100% anatase titania were obtained. A qualitative explanation of the different phase formation has been provided. Transmission Electron Microscopy was used to study particle morphology, size and agglomeration. Sizes of the titania particles produced by the designed burners varied from 10 to 100 nm, depending on processing conditions. In situ light scattering measurements were made to examine the evolution of the particle sizes. Post-sintering experiments were carried out to illustrate superior sinterability of the nanophase titania powders.

Ginkgolide A, ginkgolide B, ginkgolide C, and ginkgolide J are structurally related terpene trilactones present in Ginkgo biloba extract. Pregnane X receptor (PXR), glucocorticoid receptor (GR), and constitutive androstane receptor (CAR) regulate the expression of genes involved in diverse biological functions. In the present study, we investigated the effects of individual ginkgolides as single chemical entities on the function of human PXR (hPXR), human GR (hGR), and human CAR (hCAR). In cell-based reporter gene assays, none of the ginkgolides activated hGR or hCAR (wild-type and its SV23, SV24, and SV25 splice variants). Concentration-response experiments showed that ginkgolide A and ginkgolide B activated hPXR and rat PXR to a greater extent than ginkgolide C, whereas ginkgolide J had no effect. As determined by a time-resolved fluorescence resonance energy transfer competitive binding assay, ginkgolide A and ginkgolide B, but not ginkgolide C or ginkgolide J, were shown to bind to the ligand-binding domain of hPXR, consistent with molecular docking data. Compared with tetraethyl 2-(3,5-di-tert-butyl-4-hydroxyphenyl)ethenyl-1,1-bisphosphonate (SR12813) (a known agonist of hPXR), ginkgolide A and ginkgolide B were considerably less potent in binding to hPXR. These two ginkgolides recruited steroid receptor coactivator-1 to hPXR and increased hPXR target gene (CYP3A4) expression, as assessed by a mammalian two-hybrid assay and real-time polymerase chain reaction, respectively. In conclusion, the individual ginkgolides regulate the function of nuclear receptors in a receptor-selective and chemical-dependent manner. This study identifies ginkgolide A and ginkgolide B as naturally occurring agonists of hPXR and provides mechanistic insight into the structure-activity relationship in ligand activation of hPXR.

Bilobalide is a naturally-occurring sesquiterpene trilactone with therapeutic potential in the management of ischemia and neurodegenerative diseases such as Alzheimer's disease. In the present study, we investigated the effect of bilobalide on the activity of rat constitutive androstane receptor (rCAR) and rat pregnane X receptor (rPXR) and compared that with human CAR (hCAR) and human PXR (hPXR). Bilobalide activated rCAR in a luciferase reporter gene assay and increased rCAR target gene expression in cultured rat hepatocytes, as determined by the CYP2B1 mRNA and CYP2B enzyme activity (benzyloxyresorufin O -dealkylation) assays. This increase in hepatocyte CYP2B1 expression by bilobalide was not accompanied by a corresponding increase in rCAR mRNA level. In contrast to the activation of rCAR, the activity of rPXR, hCAR, and hPXR was not influenced by this chemical in cell-based reporter gene assays. Consistent with these results, bilobalide did not alter rPXR, hCAR, or hPXR target gene expression in rat or human hepatocytes, as evaluated by the CYP3A23, CYP2B6, CYP3A4 mRNA assays and the CYP3A (testosterone 6β-hydroxylation) and CYP2B6 (bupropion hydroxylation) enzyme activity assays. Bilobalide was not an antagonist of rPXR, hCAR, or hPXR, as suggested by the finding that it did not attenuate rPXR activation by pregnenolone 16α-carbonitrile, hCAR activation by 6-(4-chlorophenyl)imidazo\[2,1- b \]\[1,3\]thiazole-5-carbaldehyde O -(3,4-dichlorobenzyl)oxime, or hPXR activation by rifampicin in reporter gene assays. In conclusion, bilobalide is an activator of rCAR, whereas it is not a ligand of rPXR, hCAR, or hPXR. Similarly, it is an inducer of rat CYP2B1, but not of rat CYP3A23, human CYP2B6, or human CYP3A4.

Naturally occurring splice variants of human constitutive androstane receptor (hCAR) exist, including hCAR-SV23 (insertion of amino acids SPTV), hCAR-SV24 (APYLT), and hCAR-SV25 (SPTV and APYLT). An extract of Ginkgo biloba was reported to activate hCAR-SV24 and the wild type (hCAR-WT). However, it is not known whether it selectively affects hCAR splice variants, how it activates hCAR isoforms, and which chemical is responsible for the effects of the extract. Therefore, we evaluated the impact of G. biloba extract on the functionality of hCAR-SV23, hCAR-SV24, hCAR-SV25, and hCAR-WT and compared it with that of phenobarbital, di-(2-ethylhexyl)phthalate (DEHP), 6-(4-chlorophenyl)imidazo[2,1-b][1,3]thiazole-5-carbaldehyde O-(3,4-dichlorobenzyl)oxime (CITCO), and 1,4-bis-[2-(3,5-dichloropyridyloxy)]benzene (TCPOBOP) in cell-based reporter gene assays. Among the hCAR splice variants investigated, only hCAR-SV23 was activated by G. biloba extract, and this required cotransfection of a retinoid X receptor α (RXRα) expression plasmid. The extract activated hCAR-SV23 to a lesser extent than hCAR-WT, but ginkgolide A, ginkgolide B, ginkgolide C, ginkgolide J, and bilobalide were not responsible for the effects of the extract. CITCO activated hCAR-SV23, hCAR-SV24, and hCAR-WT. By comparison, phenobarbital activated hCAR-WT, whereas DEHP activated hCAR-SV23, hCAR-SV24 (with exogenous RXRα supplementation), and hCAR-WT. TCPOBOP did not affect the activity of any of the isoforms. G. biloba extract and phenobarbital did not bind or recruit coactivators to the ligand-binding domains of hCAR-WT and hCAR-SV23, whereas positive results were obtained with the controls (CITCO for hCAR-WT and DEHP for hCAR-SV23). In conclusion, G. biloba extract activates hCAR in an isoform-selective manner, and hCAR-SV23, hCAR-SV24, and hCAR-WT have overlapping, but distinct, sets of ligands.

Conflicting data exist as to whether meclizine is an activator of human pregnane X receptor (hPXR). Therefore, we conducted a detailed, systematic investigation to determine whether meclizine affects hPXR activity by performing a cell-based reporter gene assay, a time-resolved fluorescence resonance energy transfer competitive ligand-binding assay, a mammalian two-hybrid assay to assess coactivator recruitment, and a hPXR target gene expression assay. In pregnane X receptor (PXR)-transfected HepG2 cells, meclizine activated hPXR to a greater extent than rat PXR. It bound to hPXR ligand-binding domain and recruited steroid receptor coactivator-1 to the receptor. Consistent with its hPXR agonism, meclizine increased hPXR target gene expression (CYP3A4) in human hepatocytes. However, it did not increase but decreased testosterone 6β-hydroxylation, suggesting inhibition of CYP3A catalytic activity. Meclizine has also been reported to be an inverse agonist and antagonist of human constitutive androstane receptor (hCAR). Therefore, given that certain tissues (e.g., liver) express both hPXR and hCAR and that various genes are cross-regulated by them, we quantified the expression of a hCAR- and hPXR-regulated gene (CYP2B6) in cultured human hepatocytes treated with meclizine. This drug did not decrease constitutive CYP2B6 mRNA expression or attenuate hCAR agonist-mediated increase in CYP2B6 mRNA and CYP2B6-catalyzed bupropion hydroxylation levels. These observations reflect hPXR agonism and the lack of hCAR inverse agonism and antagonism by meclizine, which were assessed by a hCAR reporter gene assay and mammalian two-hybrid assay. In conclusion, meclizine is a hPXR agonist, and it does not act as a hCAR inverse agonist or antagonist in cultured human hepatocytes.

Aerosol coating processes were developed to deposit titania ceramic films onto steel and silica substrates. In situ light-scattering measurements were used to understand the deposition mechanisms in different system configurations. The conditions that were necessary to obtain uniform, nonporous, and well-adhered titania films on steel substrates were established. The as-coated films had excellent anticorrosion characteristics at room temperature, as established by the standard salt-fog test. Film crystallinity and morphology were examined using X-ray diffractometry and scanning electron microscopy; these analysis methods revealed an oriented, nanocrystalline anatase phase. Film composition was established, as a function of film thickness, using Auger electron spectroscopy and was confirmed to be stoichiometric (Ti:O = 1:2). The optical band gap and optical phonons of the deposited films were probed using spectrophotometry and Raman scattering, respectively; these analysis methods revealed a blue shift of the gap, relative to bulk anatase, and a localization of carriers in the nanometer-sized crystallites.

The objective of this study was to characterise the β-lactamase genes of cephalosporin-resistant Escherichia coli isolated from farm animals in Guangdong Province of China. Of 592 E. coli isolates recovered from farm animals from 2003–2005, 50 (8.4%) showed cephalosporin resistance. Polymerase chain reaction and sequencing analysis showed that 14 isolates (2.4%) from chickens, ducks, pigs and partridges were positive for the bla CTX-M gene (10 for bla CTX-M-14 and 4 for bla CTX-M-27 ). CMY-2 was detected for the first time in mainland China in six E. coli isolates (1.0%) from chickens and goose. Except for one isolate, bla CTX-M - and bla CMY-2 -containing isolates also harboured the bla TEM-1b gene. Conjugation experiments demonstrated that the bla CTX-M and bla TEM genes could be transferred to E. coli DH5α. Pulsed-field gel electrophoresis (PFGE) showed that the 14 CTX-M-producing isolates belonged to 12 different types. Two isolates (one from a chicken, the other from a pig) containing CTX-M-14 showed indistinguishable PFGE patterns, indicating clonal dissemination of this strain among animals from different farms. This study describes for the first time the emergence of CTX-M- and CMY-2-producing E. coli among farm animals in China, with the CTX-M-9 group being the predominant extended-spectrum β-lactamase detected.

A liquid chromatographic method with fluorescence detection was developed for simultaneous determination of norfloxacin, ofloxacin, ciprofloxacin, pefloxacin, lomefloxacin, danofloxacin, enrofloxacin, sarafloxacin, difloxacin, oxolinic acid, and flumequine in milk. The samples were extracted with 10% trichloroacetic acid/acetonitrile (9 + 1, v/v) and cleaned by Strata-X reversed-phase solid-phase extraction cartridges. The 11 quinolones were separated on a reversed-phase C18 column (Hypersil BDS-C18) with mobile phase gradient elution and detected with fluorescence by means of a wavelength program. The recoveries for milk fortified with the 11 quinolones at 3 levels were 69–88%, with acceptable relative standard deviations of

A random particle computer simulation (in three dimensions) was conducted to investigate the structure and aggregation characteristics of small clusters (containing limited numbers of primary particles per cluster). Though an individual cluster of small size does not satisfy the power law, it was found that these aggregated clusters are fractal-like and comply with the fractal power law form in a statistical sense. This statistically averaged fractal dimension decreases as the clusters become smaller. A cluster-restructuring model is further developed to simulate the topological evolution of dendritic structured materials due to sintering at high temperatures. Results indicate that the cluster fractal dimension increases as sintering proceeds for small clusters, in contrast to results for large clusters wherein the topology is retained and the fractal dimension remains constant. A relationship of the fractal dimension change with the normalized surface area of dendrites for different-sized clusters is established. Copyright 1999 Academic Press.