Biochemical mechanism studies of venlafaxine by metabonomic method in rat model of depression

BACKGROUND

Venlafaxine is a new antidepressant that has a chemical structure and neuropharmacologic profile distinct from those of existing antidepressants. The studies about the mechanism of pharmacological action of venlafaxine mostly investigated the effects of venlafaxine on 5-hydroxytryptamine (5-HT), norepinephrine (NE) and dopamine (DA) levels, while only few studies examined the effects on the metabolites levels and ratio of these monoamines neurotransmitters.

AIM

To study the biochemical mechanism of venlafaxine through determining the metabolism of monoamine neurotransmitters in brain tissues of rat model of depression after administration of venlafaxine using metabonomic method.

MATERIALS AND METHODS

The rat model of depression was established by using the methods of separation and chronic unpredictable stress. We have determined 5-HT, NE, DA and their metabolites, i.e., 5-hydroxyindole-3-acetic acid (5-HIAA), 4-hydroxy-3-methoxyphenylglycol (MHPG) sulfate, 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) in rat brain tissues by liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) following chronic administration of different venlafaxine doses (8, 16, 32 mg·kg-1) and saline solution for 14 days. Linear discriminant analysis (LDA) and principal components analysis (PCA) were used in data analysis of metabonomic.

RESULTS

Compared with saline, venlafaxine could significantly increase brain 5-HT and NE levels at middle dose (16 mg·kg-1) or high dose (32 mg·kg-1), especially at middle dose. These increases were greater than those seen with the comparable dose of selective serotonin reuptake inhibitor (SSRI), fluoxetine, under the same experimental conditions.

CONCLUSIONS

Venlafaxine lowers brain neurotransmitter metabolite levels by decreasing brain neurotransmitters turnover. Venlafaxine could correct the disorder of neurotransmitters' metabolism and coordinate the balance of 5-HT, NE and DA to reach the anti-depressed function.

An integrated cancer biomarker information system

Rapid progress in functional genomics is yielding unparalleled opportunities for cancer biomarker discovery. Several procedures including data collection, analysis, verification, and visualization are necessary to identify cancer biomarkers from continuously updated microarray data, which are derived from multiple tissue sources using various methods. BioMarker is designed to integrate these procedures in a user-friendly manner, for practical application by cancer researcher and clinicians. From the feedback of clinical and research application, BioMarker is the first effort to provide a system that facilitates all aspects of biomarker discovery from microarray datasets.

Evaluation of a PCR test for the detection of Haemophilus paragallinarum in China

The application of a recently described PCR test for the detection of Haemophilus paragallinarum in China is described. The test was used to examine a total of 127 chickens sourced from a challenge trial (38 chickens), a respiratory disease-free experimental chicken farm (50 chickens) and eight farms with suspect infectious coryza (IC) outbreaks (39 chickens). The PCR results were compared with traditional culture. The PCR detected 14/14 infected birds in the challenge trial as compared with 13/14 for culture. The 50 chickens from the disease-free experimental farm were all negative by both PCR and culture. PCR yielded 15/39 birds and 6/8 commercial farms positive as compared with 8/39 birds and 4/8 farms positive by culture. All farms positive by PCR had chickens showing the typical clinical signs of IC, indicating that culture failed to confirm coryza on two farms that had the typical clinical signs of the disease. Although chickens on two commercial farms were thought initially to be suffering from coryza, detailed clinical examination yielded no birds with typical clinical signs. The 12 chickens examined from these two farms were negative by both PCR and culture. The results suggest that the PCR test for H. paragallinarum is a suitable alternative to culture even under the typical field and laboratory conditions that operate in China.

Comparative fasting bioavailability and pharmacokinetic properties of 2 formulations of glucosamine hydrochloride in healthy Chinese adult male volunteers

Glucosamine (CAS 66-84-2) hydrochloride is an amino monosaccharide indicated for the treatment of arthrosis, especially osteoarthritis of the knee joint. This study was conducted to assess and compare the pharmacokinetic (PK) properties, bioavailability of a newly developed dispersible tablet formulation (test) of glucosamine hydrochloride with those of an established branded capsule formulation (reference) in healthy Chinese adult male volunteers.This single-dose, randomized, open-label, 2-period crossover study was conducted in 18 healthy Chinese adult male volunteers under fasting condition. Plasma samples were collected at pre-specified times over a 12-h period following administration in each period and analyzed the plasma glucosamine concentrations by Liquid Chromatography coupled with Tandem Mass Spectrometry (LC/MS/MS) method. The mean (SD) PK parameters of Cmax, Tmax, AUC0-12, and AUC0-∞ after administration of the test and reference formulations were, respectively, as follows: Cmax, 907.01 (444.22) vs. 944.40 (429.89) ng/mL, Tmax, 3.03 (0.95) vs. 3.30 (0.99) hours, AUC0-12, 2891.41 (1352.30) vs. 2889.69 (925.48) ng/mL/h, and AUC0-∞, 3029.90 (1321.36) vs. 3091.87 (870.36) ng/mL/h. The mean (SD) t1/2 was 1.10 (0.52) hours for the test formulation and 1.50 (1.17) hours for the reference formulation. On ANOVA, neither period nor sequence effects were observed for any PK properties. The relative bioavailability of the test formulation was 98.3% assessed by AUC0-12. The 90% CIs of glucosamine for the log-transformed ratios of Cmax, AUC0-12, and AUC0-∞ were 78.4-113.9%, 80.8-108.5% and 80.8-105.8%, respectively, meeting the predetermined criteria for bioequivalence of SFDA.

SU-E-T-269: The Evaluation of Copper as an Alternative for Cerrobend Electron Shielding

PURPOSE

To evaluate the replacement of Cerrobend by copper for electron beam cutouts.

METHODS

The dosimetric comparisons for circular copper-and Cerrobend-cutouts with diameters (1.0, 2.0, 3.0, 5.0, 7.5, 10.0, and 12.5 cm) were made using electron beams with energies (6, 9, 12, 16, and 20 MeV) from 3 Varian accelerators. A PTW Farmer chamber (0.125cc-volume) was used for larger cutouts (diameters > 2cm), and an electron-diode for the 2 smallest cutouts. Also a Markus parallel plate chamber was used.

RESULTS

(1) The tests showed little difference for the electron dosimetric characteristics, Eo, Eop, R50, Rp, and dmax. For larger cutout, the parameters were virtually the same for copper and Cerrobend. for smaller cutout (diameter = 3cm), small discrepancies were observed i.e. differences < 1mm for R50, Rp and dmax, =0.1MeV for Eop, and =0.3MeV for Eo. (2) The larger-cutout outputs at dmax were also virtually the same (difference = 0.6%). For smaller cutouts (diameters = 3cm), the copper outputs were 2.0%∼5.0% higher than Cerrobend. (3) For lower energy electrons (<12MeV), more larger-angle scattered electrons from higher-Z Cerrobend raise the Cerrobend percentage-depth-dose (PDD) curve at shallow-depths, and more forward scatter dose after dmax from lower-Z copper shifts the copper PDD slightly away from the one of Cerrobend. for higher energy electrons (= 12MeV), the shallow-dose difference becomes smaller for both cutouts, but even more forward-scattered dose from copper shifts copper's PDD further away from Cerrobend's. (4) The higher X-ray transmission through copper is also observable; i.e. 12%, 10%, and 7% for 20MeV, 16MeV, and 12MeV, respectively, but such small transmitted amount is clinically insignificant.

CONCLUSIONS

Except for a higher x-ray transmission, other dosimetric differences brought in by the replacement of Cerrobend by copper cutout are negligible.

BaTiO3(001)-(2×1): surface structure and spin density

Using surface x-ray diffraction and ab initio calculations we present a model of the BaTiO3(001)-(2×1) surface structure, which has not been considered so far. While the crystal is terminated by two TiO2 layers similarly to SrTiO3(001)-(2×1), we find that one out of two surface layer Ti-atoms resides in a tetragonal pyramidal oxygen environment. This peculiar geometry leads to a metallic and magnetic surface involving local magnetic moments up to 2μ(B) in magnitude located at surface Ti and O atoms. Our results are important for the understanding of the intrinsic surface metallicity of insulating oxides in general.

Fabrication using a rapid prototyping system and in vitro characterization of PEG-PCL-PLA scaffolds for tissue engineering

In the field of tissue engineering new polymers are needed to fabricate scaffolds with specific properties depending on the targeted tissue. This work aimed at designing and developing a 3D scaffold with variable mechanical strength, fully interconnected porous network, controllable hydrophilicity and degradability. For this, a desktop-robot-based melt-extrusion rapid prototyping technique was applied to a novel tri-block co-polymer, namely poly(ethylene glycol)-block-poly(epsilon-caprolactone)-block-poly(DL-lactide), PEG-PCL-P(DL)LA. This co-polymer was melted by electrical heating and directly extruded out using computer-controlled rapid prototyping by means of compressed purified air to build porous scaffolds. Various lay-down patterns (0/30/60/90/120/150 degrees, 0/45/90/135 degrees, 0/60/120 degrees and 0/90 degrees) were produced by using appropriate positioning of the robotic control system. Scanning electron microscopy and micro-computed tomography were used to show that 3D scaffold architectures were honeycomb-like with completely interconnected and controlled channel characteristics. Compression tests were performed and the data obtained agreed well with the typical behavior of a porous material undergoing deformation. Preliminary cell response to the as-fabricated scaffolds has been studied with primary human fibroblasts. The results demonstrated the suitability of the process and the cell biocompatibility of the polymer, two important properties among the many required for effective clinical use and efficient tissue-engineering scaffolding.