No abstract

ABSTRACT:The aim of this study was to determine the properties of β-glycerol phosphate (GP)/collagen/chitosan blended films for the potential application to skin tissue engineering. Various ratios of collagen to chitosan (8:2 and 7:3) and amounts of GP (0.5, 1, and 1.5% w/w) of total polymers were blended in solution form and cast into films. According to SEM images, the casted films showed a non-porous surface. For the mechanical properties, the prepared scaffolds exhibited the maximum elongation ranging from 15-23%, which is lower than those found by other researchers. However, the maximum tensile strength values of the scaffolds made from the collagen/chitosan (ratios 7:3) crosslinked with 0.5 or 1% w/w GP were in the range of 8-10 MPa which achieve the recommended values for application in skin tissue engineering. The scaffolds showed ability to retain their structure after immersion in phosphate buffer saline solution (pH 7.4) for 1 h, and their volume increased about 20%. After incubation in collagenase solution (200 U of collagenase/5 g of collagen) at 37°C, the scaffolds were degraded within 24 to 26 days which coincides very well with the healing time of acute wounds (about 25 days). FT-IR studies revealed the possibility of an interaction of GP with collagen/chitosan via ionic interaction that enhances the strength and stability of the prepared scaffold. The results from an in vitro culture study showed that the keratinocyte HaCaT culture could adhere well and grow on the selected scaffold with a typical morphology at 98.1 ± 1.8% of the control (cells growth on tissue culture plate) after cultivation for 5 days. The results suggest the potential of the GP/collagen/chitosan blended films for use as skin scaffolds.

Platelets play a critical role in pathogenesis of cardiovascular disorders and strokes. The inhibition of platelet function is beneficial for the treatment and prevention of these diseases. The phytochemical investigation of stilbenoids from Gnetum macrostachyum Hook. f. led to the isolation of trans-resveratrol (1), isorhapotigenin (2), gnetol (3), bisisorhapontigenin B (4), gnetin C (5), parvifolol A (6), latifolol (7) and gnetuhainin C (8). The isolated stilbenoids were evaluated for in vitro antiplatelet activities via agonist-induced platelet aggregation and static platelet-collagen adhesion assays using washed human platelets. Compounds 1, 2 and 3 were active in the inhibition of arachidonic acid (AA)-induced platelet aggregation. Compound 2 and its dimer, compound 4, were the most active stilbenoids in thrombin-induced platelet aggregation. Moreover, compounds 4, 5 and 6, tended to be more potent than monomeric and trimeric stilbenoids in a human platelet-collagen adhesion assay under static conditions. This is the first report of the antiplatelet activity of stilbenoids isolated from G. macrostachyum.

Hb Constant Spring (HbCS), a nondeletional alpha-thalassemia, is most prevalent in southern Chinese and southeast Asian populations. In conjunction with alpha-thalassemia-1 or in the homozygous state, it is an important cause of HbH disease. The present study was designed to test the efficiency of different diagnostic methods in detecting HbCS. The following laboratory tests were applied to blood samples from 1000 pregnant women attending an antenatal clinic at Buddhachinaraj Hospital in Phitsanulok, Thailand: mutation specific restriction enzyme digestion (RED), amplification refractory mutation system (ARMS) and automated high-performance liquid chromatography (HPLC). The results demonstrate that the DNA-based methods, RED and ARMS, are efficient diagnostic tools in detecting HbCS in homozygotes and heterozygotes, whereas automated HPLC gave accurate results for homozygous HbCS, but misidentified (no peak) some cases of HbCS trait. Standard hematological methods (determination of mean cell hemoglobin and mean cell volume) did not efficiently differentiate homozygous HbCS and HbCS trait from samples with normal alpha-globin chains. We conclude that RED is the preferable method for HbCS screening and then confirmed diagnostic testing using ARMS. Cases unresolved by ARMS should be clarified by appropriate methods such as DNA sequencing.

This study aimed to investigate the effects of ethanol extracts of Butea superba in increasing intracavernous pressure (ICP) in vivo. The extracts were prepared from fresh and dried root cores and fresh and dried root barks. Penile erection was induced in aged rats by electrical stimulation of the cavernous nerve. Cavernous smooth muscle relaxation was also observed in vitro in the presence of the extract, cGMP or isobutyl-methylxanthine (IBMX) alone or the extract together with cGMP or IBMX. The dried root core extract from Phrae was the most effective in increasing the ICP. The dose-response relationship study revealed a bell-shape curve with the maximum effective dose at 1 mg/kg. The ICP of the control and 1 mg/kg extract-treated animals were 45.3 +/- 2.5 and 100.9 +/- 14.0 mmHg, respectively. The extract, cGMP and IBMX alone induced dose dependent muscle relaxation. B. superba significantly enhanced the effects of cGMP and IBMX. The results suggest that ethanol extracts of B. superba are effective in enhancing penile erection. The dried root core extract from Phrae is the most effective part with a maximal dose of 1 mg/kg. The results also suggest that B. superba may act through cAMP/cGMP pathways.