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Biomedical subjects

Y Pan

Publications and source records attributed to Y Pan.

At least 19 recordsLinked to original sources
PubMed2006

Behavioral and biochemical studies of total furocoumarins from seeds of Psoralea corylifolia in the chronic mild stress model of depression in mice.

Depression is related to alterations of the monoamine oxidase (MAO), hypothalamic-pituitary-adrenal (HPA) axis, and oxidative systems, and some antidepressants achieve their therapeutic effects through alteration of following biochemical markers of depression: MAO-A and MAO-B activities, cortisol levels, superoxide dismutase (SOD) activity and malondialdehyde (MDA) levels. The seeds of Psoralea corylifolia, otherwise known as Buguzhi, have long been used for treatments of various symptoms associated with aging in China. Furocoumarins are the most widespread secondary metabolites in this species. The present study was designed to evaluate the potential antidepressant-like activity of total furocoumarins of P. corylifolia (TFPC) in the chronic mild stress (CMS) model of depression. Mice subjected to CMS exhibited a reduction in sucrose intake. Conversely, brain MAO-A and MAO-B activities, plasma cortisol levels, and liver SOD activity and MDA levels were increased following CMS exposures. The time-course for reversal of CMS-induced deficits in sucrose consumption by TFPC was dose-dependent. Thus, the statistically significant effect of the higher dose of TFPC (50 mg/kg body wt.) was observed after 3 days of treatment, while 6 days of treatment were required in the group receiving a lower dose (30 mg/kg body wt.) of TFPC. TFPC reversed these biochemical changes. These results suggest that TFPC may possess potent and rapid antidepressant properties that are mediated via MAO, the HPA axis and oxidative systems and these antidepressant actions could make TFPC a potentially valuable drug for the treatment of depression in the elderly.

Animals↗
PubMed2006

Behavioral, neurochemical and neuroendocrine effects of the ethanolic extract from Curcuma longa L. in the mouse forced swimming test.

Curcuma longa L. (turmeric) has been used for centuries in traditional Chinese medicine as a treatment for mental disorders including depression. The studies described here were undertaken to determine the behavioral, neurochemical and neuroendocrine effects of the ethanolic extract from Curcuma longa using the forced swimming test (FST) in male ICR strain of mice. The ethanolic extract was found to reduce the duration of immobility in the mouse FST when orally administered for 21 days. The extract markedly attenuated swim stress-induced decreases in serotonin, 5-hydroxyindoleacetic acid, noradrenaline and dopamine concentrations, as well as increases in serotonin turnover. Furthermore, the ethanolic extract of Curcuma longa significantly reversed the swim stress-induced increases in serum corticotropin-releasing factor and cortisol levels. Under these conditions, the ethanolic extract of Curcuma longa was partly different from fluoxetine and amitriptyline. These results suggested that antidepressant properties of the ethanolic extract of Curcuma longa was mediated through regulations of neurochemical and neuroendocrine systems and it may be a useful agent against depression.

Amitriptyline↗
PubMed2006

Resistance of Listeria monocytogenes biofilms to sanitizing agents in a simulated food processing environment.

The objective of this study was to evaluate the resistance of biofilms of Listeria monocytogenes to sanitizing agents under laboratory conditions simulating a food processing environment. Biofilms were initially formed on stainless steel and Teflon coupons using a five-strain mixture of L. monocytogenes. The coupons were then subjected to repeated 24-h daily cycles. Each cycle consisted of three sequential steps: (i) a brief (60 s) exposure of the coupons to a sanitizing agent (a mixture of peroxides) or saline as a control treatment, (ii) storage of the coupons in sterile plastic tubes without any nutrients or water for 15 h, (iii) and incubation of the coupons in diluted growth medium for 8 h. This regimen was repeated daily for up to 3 weeks and was designed to represent stresses encountered by bacteria in a food processing environment. The bacteria on the coupons were reduced in number during the first week of the simulated food processing (SFP) regimen, but then adapted to the stressful conditions and increased in number. Biofilms repeatedly exposed the peroxide sanitizer in the SFP regimen developed resistance to the peroxide sanitizer as well as other sanitizers (quaternary ammonium compounds and chlorine). Interestingly, cells that were removed from the biofilms on peroxide-treated and control coupons were not significantly different in their resistance to sanitizing agents. These data suggest that the resistance of the treated biofilms to sanitizing agents may be due to attributes of extracellular polymeric substances and is not an intrinsic attribute of the cells in the biofilm.

Bacterial Adhesion↗
PubMed2006

High pH accelerates GABA deactivation on perch-rho1B receptors.

The ionotropic GABA(C) receptor, formed by GABA rho subunits, is known to be modulated by a variety of endogenous compounds, as well as by changes in pH. In this study, we explore the proton sensitivity of the GABA rho subunits cloned from the perch retina, and report a novel action of high pH on the homomeric receptor formed by one of the GABA rho subunits, the perch-rho(1B) subunit. Raising extracellular pH to 9.5 significantly accelerated GABA deactivation responses elicited from oocytes expressing the perch-rho(1B) subunit, and reduced its sensitivity to GABA. The change in the kinetics of the GABA-offset response occurred without altering the maximum response amplitude, and the reduced GABA sensitivity was independent of membrane potential. Although acidification of the extracellular solution also accelerated GABA deactivation for all other GABA rho receptors examined in this study, the effects of high pH were unique to the homomeric receptor formed by the perch-rho(1B) subunit. In addition, we found that, unlike the effects on the response to the naturally occurring full agonist GABA, the responses elicited by partial agonists (imidazole-4-acetic acid (I4AA) and beta-alanine) in the presence of the high pH solution showed a significant reduction in the maximum response amplitude. When considered in terms of a model describing the activation of GABA(C) receptors, in which pH can potentially affect either the binding affinity or the rate of channel closure, the results were consistent with the view that external alkalization reduces the gating efficiency of the receptor. To identify the proton sensitive domain(s) of the perch-rho(1B) receptor, chimeras were constructed by domain swapping with other perch-rho subunits. Analysis of the pH sensitivities of the various chimeric receptors revealed that the alkaline-sensitive residues are located in the N-terminal region of the perch-rho(1B) subunit.

Animals↗
PubMed2006

Acoustic waves generated by a laser line pulse in a hollow cylinder.

A theoretical solution is proposed to predict acoustic waves generated in a homogeneous and isotropic hollow cylinder by a laser line source under either ablation or thermoelastic regime. The Fourier series expansion is introduced for one spatial coordinate to solve this transient response problem. Theoretical displacements are obtained in both regimes for aluminum hollow cylinders with various thickness including a rod of the same size. The corresponding displacements are observed experimentally by the laser ultrasonic technique. Agreement has been found in the time arrival, shape and relative amplitude of surface waves and various longitudinal and transverse bulk waves. These acoustic waves are further identified by the ray trajectory analysis. This work will be helpful when dealing with the inverse problem of the nondestructive evaluation of hollow cylindrical parts.

Journal Article↗
PubMed2006

Identification of laser-generated ultrasounds in the response of the cylinder over time and space.

A theoretical solution is presented to identify laser-generated ultrasounds in the transient response over time and space of a cylinder impacted by a laser line pulse. Theoretical radial displacements at various observation angles are obtained for an aluminum cylinder under thermoelastic regime. The corresponding displacements are observed experimentally by the laser ultrasonic technique. Good agreement is found in the time arrival, shape and relative amplitude of surface waves and various longitudinal and transverse bulk waves. These laser-generated ultrasounds are further identified by the ray trajectory analysis. This work will be helpful for the inverse problem of the nondestructive evaluation of cylinder parts.

Journal Article↗
PubMed2006

The transient response of a transversely isotropic cylinder under a laser point source impact.

The transient response of a transversely isotropic cylinder under a laser point source impact is solved theoretically. The radial displacement generated by the laser under the ablation regime is numerically calculated by introducing Fourier series expansion and two-dimensional Fourier transform. The validity of this theoretical solution is demonstrated on a fiber reinforced composite cylinder with a strong anisotropy. Experimental displacements are detected at the cylinder surface by the laser ultrasonic technique, and are analyzed by the ray trajectories. Corresponding theoretical displacements are calculated numerically and compared to the experimental signals. Good agreement is found. The diffraction effect caused by the cusp is observed in both theory and experiment.

Journal Article↗
PubMed2006

On the use of laser-ultrasonics technique to excite selectively cylinder acoustic resonances.

Acoustic propagation in the transverse plane of a cylinder is considered in this paper. The acoustic source is a line along the axis z of the cylinder coordinates, obtained by focusing the beam of a pulsed laser on the surface of the cylinder. Point detection is performed with a laser interferometer. By adequately combining elementary signals measured for a large number of relative source-receiver positions, a signal is synthesized containing the basic acoustic resonances of the cylinder. Various elementary signal combinations allow us to select the observed acoustic modes related to Whispering Gallery modes and to Rayleigh surface waves. The changes in the signal spectrum are discussed. These acoustic modes are experimentally selected and observed at ultrasonic frequencies for the first time.

Journal Article↗
PubMed2006

Intraocular pressure following phacoemulsification in patients with and without exfoliation syndrome: a 2 year prospective study.

AIM: To determine the long term intraocular pressure (IOP) response to phacoemulsification in patients with and without exfoliation syndrome (XFS). METHODS: Prospective, multicentre, cohort study with the following inclusion criteria: age over 50 years, open iridocorneal angle, and cataract. Two groups were enrolled: those with XFS and those without. The main outcome was mean IOP reduction 2 years after phacoemulsification cataract extraction (PCE). Univariate and multivariate analyses were performed. RESULTS: 183 patients were enrolled, 71 with and 112 without XFS. There were 29 patients with glaucoma in both groups. Mean baseline IOP was higher in XFS compared to control eyes (17.60 (SD 3.23) mm Hg v 16.08 (3.18) mm Hg, p = 0.002). Overall IOP reduction was significantly greater in the XFS group at the 2 year time point (-1.85 mm Hg v -0.62 mm Hg in the controls (p = 0.0037)). Multivariate analysis demonstrated that the IOP lowering effect in the XFS group may be related to irrigation volume at the time of surgery. In the subgroup analyses IOP lowering was significantly greater in the XFS and XFG patients than in controls without glaucoma, and POAG controls, respectively. The percentage of patients with a postoperative IOP spike was similar and relatively high in both XFS and control groups (34% v 25%; p = 0.54). CONCLUSION: IOP decreases more in patients with XFS following PCE compared to control eyes without XFS. This effect is more pronounced in glaucoma patients and persists for at least 2 years.

Aged↗
PubMed2006

Electron beam damage studies of synthetic 6-line ferrihydrite and ferritin molecule cores within a human liver biopsy.

In order to achieve an accurate understanding of the crystal structure of 6-line ferrihydrite (6LFh) and ferritin molecule cores within a human liver biopsy using transmission electron microscopy (TEM), electron beam damage should be considered. For the case of 6LFh, the electron energy loss near-edge structure (ELNES) of core ionisation edges in the electron energy loss spectrum (EELS) combined with multiple linear least-square (MLLS) fitting of reference spectra together with analysis of selected area electron diffraction (SAED) patterns suggests that the iron in 6LFh is solely octahedrally coordinated Fe3+. With increasing electron dose, an increasing percentage of this octahedrally coordinated Fe3+ migrates to tetrahedral sites. When the dose exceeds 3 x 10(8) electrons/nm2, Fe2+ is found to be present in the material. This method also indicates that the iron in ferritin molecule cores within a human liver biopsy is the same as in 6LFh, entirely Fe3+ in octahedral coordination with oxygen. Again the percentage of octahedrally coordinated Fe3+ decreases as the accumulated electron dose increases and Fe2+ is produced in the liver biopsies when the electron dose exceeds 10(6)electrons/nm2.

Adult↗
PubMed2006

cisRED: a database system for genome-scale computational discovery of regulatory elements.

We describe cisRED, a database for conserved regulatory elements that are identified and ranked by a genome-scale computational system (www.cisred.org). The database and high-throughput predictive pipeline are designed to address diverse target genomes in the context of rapidly evolving data resources and tools. Motifs are predicted in promoter regions using multiple discovery methods applied to sequence sets that include corresponding sequence regions from vertebrates. We estimate motif significance by applying discovery and post-processing methods to randomized sequence sets that are adaptively derived from target sequence sets, retain motifs with p-values below a threshold and identify groups of similar motifs and co-occurring motif patterns. The database offers information on atomic motifs, motif groups and patterns. It is web-accessible, and can be queried directly, downloaded or installed locally.

Animals↗
PubMed2006

Acoustic waves generated by a laser point pulse in a transversely isotropic cylinder.

A three-dimensional (3D) model is presented to predict the acoustic waves generated by a laser point pulse in a transversely isotropic cylinder. The Fourier series expansion and the two-dimensional Fourier transform are introduced to calculate the 3D transient response under either the ablation or the thermoelastic generation. The presented physical model and the numerical inverse scheme are applied to a fiber reinforced composite cylinder with a strong anisotropy. Experimental radial displacements of the cylinder surface are detected by the laser ultrasonic technique and analyzed by the ray trajectories for both generation regimes. Corresponding theoretical displacements are obtained numerically and compared to the experimental signals. Good agreement is found between theoretical and experimental results. The focusing effects that anisotropy gives rise to are observed in both theory and experiment under either regime.

Journal Article↗
PubMed2005

Effects of cassia oil on serum and hepatic uric acid levels in oxonate-induced mice and xanthine dehydrogenase and xanthine oxidase activities in mouse liver.

We investigated the hypouricemic effects of cassia oil extracted from Cinnamomum cassia using hyperuricemic mice induced by potassium oxonate, and its inhibitory actions against liver xanthine dehydrogenase (XDH) and xanthine oxidase (XOD) activities. Oral administration of cassia oil significantly reduced serum and hepatic urate levels in hyperuricemic mice in a time- and dose-dependent manner. At doses of 450 mg/kg of cassia oil or above, serum urate levels of the oxonate-pretreated mice were not different from the normal control mice. Cassia oil at 600 mg/kg was found to be as potent as allopurinol, which reduced hepatic urate levels to lower than normal. In normal mice, urate levels in liver, but not in serum, were altered with dose-dependent decrease after cassia oil treatment. Furthermore, the ratio, liver uric acid/serum uric acid, was determined after cassia oil administration with time- and dose-dependent decreases in hyperuricemic mice. The positive dose-dependent decrease ratio was also observed after cassia oil treatment in the normal animals. The decreased extent of ratio elicited by cassia oil in normal mice appeared to be greater than that in the hyperuricemic animal. In addition, cassia oil significantly exhibited marked reductions in liver XDH/XOD activities, with an apparent dose-dependence in the normal and hyperuricemic mice. The onset of inhibition in enzyme activities elicited by allopurinol was much higher than that elicited by cassia oil. These results suggested that hypouricemic effects of cassia oil could be explained, at least partly, by inhibiting liver in vivo activities of XDH/XOD.

Administration, Oral↗
PubMed2005

Overexpression of DARPP-32 in colorectal adenocarcinoma.

Dopamine and cAMP-regulated phosphoprotein (DARPP)-32 is a phosphoprotein that is centrally involved in dopamine signalling pathways. It may play an important role in gastric tumorigenesis. Our aim is to investigate the expression of DARPP-32 protein in colorectal adenocarcinoma. The expression of DARPP-32 was evaluated by immunohistochemical SABC staining and Western blotting. DARPP-32 was specifically localised in colorectal epithelium. The expression of DARPP-32 in colorectal adenocarcinoma tissues 33/42, 78.57% was higher than that in normal colon epithelial tissues (31/60, 51.67%, p <0.05). There was no significant relationship between the expression of DARPP-32 and the differentiation, metastasis and Dukes' stage of colorectal adenocarcinoma (p >0.05). Both DARPP-32 and its truncated isoform t-DARPP were overexpressed in colorectal adenocarcinoma (t=2.306, p=0.028), while t-DARPP was more frequently detected. These results showed that DARPP-32 may play an important role in the regulation of normal colorectal epithelial biology and carcinogenesis.

Adenocarcinoma↗
PubMed2005

Identification of laser generated acoustic waves in the two-dimensional transient response of cylinders.

The published model [Appl. Phys. Lett. 82, 4379-4381 (2003)] for the two-dimensional transient wave propagation in a cylinder is modified to avoid the inherited integration of the numerical inverse scheme. The Fourier series expansion is introduced for one spatial coordinate to resolve the transient response problem: theoretical radial displacements in either the ablation or the thermoelastic regime are obtained with little numerical noise and short computation time. The normal mode expansion method fails to deliver results with the same accuracy. Acoustic waves are fully identified by the ray trajectory analysis. These identified waves are further verified on the experimental results observed with the laser ultrasonic technique.

Journal Article↗
PubMed2005

Baseline IOP predicts selective laser trabeculoplasty success at 1 year post-treatment: results from a randomised clinical trial.

BACKGROUND/AIMS: The efficacy and safety of selective laser trabeculoplasty (SLT) has been found to be equivalent to argon laser trabeculoplasty (ALT). Since SLT produces significantly less disturbance to the trabecular meshwork and is theoretically more repeatable than ALT, it has potential to replace ALT as the standard procedure to treat medically uncontrolled open angle glaucoma. This study's objective is to determine factors that predict successful SLT at 1 year post-treatment. METHODS: As part of a randomised clinical trial comparing the efficacy and safety of SLT to ALT, data on 72 SLT patients were collected, and successful SLT defined as having an SLT induced intraocular pressure (IOP) reduction of >or=20% at 1 year post-treatment follow up. RESULTS: 43 out of the 72 patients who had completed their 1 year follow up visit had an IOP reduction of >or=20% from baseline. No glaucoma risk factors studied predicted successful SLT. The amount of trabecular meshwork pigmentation was not a significant predictor. However, it was discovered that baseline IOP strongly predicted SLT success (odds ratio=1.16; p=0.0001). CONCLUSION: SLT success was significantly predicted by baseline IOP but not by age, sex, other glaucoma risk factors, type of open angle glaucoma, or by degree of trabecular meshwork pigmentation.

Adult↗