cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.14457/cu.the.2009.1588
title: The effect of cyclic loading on shear bond strength of fiber post to human root dentin using different adhesive systems and resin cements

description: The purpose of this study was to evaluate the effect of cyclic loading on shear bond strength and microleakage between fibre reinforced post and root canal dentin using various luting cements. Eighty extracted maxillary central incisors and maxillary canines were used. Teeth were decoronated and endodontically treated. Post space of 11 mm was prepared. Samples were divided into 8 groups (n=10) according to the luting cements used (Superbond C&B, Panavia F 2.0, Maxcem Elite and Rely X Unicem) and with and without cyclic loading. D.T.Light post#3 was luted into the prepared post space following the manufacturer’s recommendation, 20 teeth for each luting cements. After that 10 teeth of each luting cements (40 specimens) were submitted under cyclic loading; 1X106 cycles. All specimens were serially sliced into three 1.5-mm-thick slabs for the push out test. After that each teeth were cut from the apex 5 mm then the middle portion specimen with 5 mm height was evaluated. Methylene blue solution was used for dye penetration. Dye penetration distance was evaluated by measuring the distance using stereomicroscope at 25X magnification and Pixera software. Two-way analysis of variance (ANOVA) revealed that only different luting cements affected the push out bond strength. Superbond C&B provided the highest bond strength while Maxcem Elite provided the lowest bond strength. For microleakage, two-way analysis of variance (ANOVA) revealed that both the type of luting cements and the cyclic loading significantly affected microleakage of fibre reinforced post bonded to root canal dentin. The microleakage only in Panavia F 2.0 groups with cyclic loading were significantly higher than Panavia F 2.0 groups without cyclic loading.
DOI: 10.14457/cu.the.2009.1589
title: Topoisomerase i inhibitory activty from Thai medicinal plants in yeast cell-based assay

description: Topoisomerase I is an important therapeutic target in cancer chemotherapy. We are interested in the continuing discovery of new topoisomerase I-targeted agents from Thai medicinal plants with previously reported as cytotoxicity by using Yeast cell-based assay. The transformant yeast containing Arabidopsis thaliana topoisomerase I gene was developed to achieve controllable expression of the topoisomerase I enzyme. From the screening of 27 Thai medicinal plants, 6 ethanolic plant-part extracts; root and leaf of Rhinacanthus nasutus, whole plant of Grangea maderaspatana, caudex of Stephania suberosa, rhizome of Curcuma longa and rhizome of Curcuma zedoaria, showed inhibitory activities of enzyme topoisomerase I. The extract of G. maderaspatana was selected for further study to determine the bioactive compounds since it has never been reported for its topoisomerase I inhibitory activity before. Bioassay-guided fractionation from whole plant of G. maderaspatana by yeast cell– based assay led to the identification of two bioactive compounds. They are sesquiterpene lactone namely, (-)-frullanolide and (-)-7α-hydroxyfrullanolide. Their structures were determined by spectroscopic methods and compared with previous reports. These compounds exhibited topoisomerase I inhibitory activities by yeast cell-based assay. They also processed in vitro anti-cancer activities against human cell lines, KB oral cavity cancer, MCF-7 breast cancer, and NC-H187 small lung cancer. This is the first report of cytotoxicity due to topoisomerase I inhibitory mechanism of two compounds from G. maderaspatana.
DOI: 10.14457/cu.the.2009.1590
title: Effects of hom nil rice and black glutionus rice extracts on mutagenicity of nitrite-treated aminopyrene and nitrite-treated chicken extract using ames test

description: The extracts from raw, cooked, and fermented of Hom Nil rice (Oryza sativa L.) and black glutinous rice (Oryza sativa L.) showed no mutagenicity on Salmonella typhimurium TA 98 and TA 100 in Ames test. After nitrite treatment in acid condition (pH3.0-3.5) the mutagenicity was detected. The mutagenic modification of rice extracts was evaluated using two models of mutagen; nitrite-treated chicken extract and nitritetreated 1-aminopyrene, and two models of antimutagenicity; antiformation and antimutagen. The results showed that the extract of cooked Hom Nil rice and all kinds of fermented rice could inhibit the formation of mutagen occurred during the reaction between nitrite and chicken extract and reaction between nitrite and 1-aminopynene respectively. The antiformation effect might be due to some components only in Hom Nil rice which increased after cooking and some components in fermented rice such as aglycone. These components might inhibit nitrosation and/or scavenge mutagen that occurred during nitrosation. However, the other rice extracts enhanced the mutagenicity of both mutagens. The study of antimutagenicity of rice extracts toward nitrite-treated chicken extracts and nitrite-treated 1-aminopyrene showed that all of rice extracts reduced the mutagenicity of both nitrite-treated mutagens. The protective effects of these rice extracts might be due to the presence of some components that might scavenge mutagens and/or inhibit bacterial enzyme. In addition, there were similar trends between the antimutagenicity of black glutinous rice extracts and the antioxidant activity and total phenolic contents assays; it was higher than that of Hom Nil rice extracts. The fermented rice extracts had the highest antioxidant activity and total phenolic contents. The results from this study suggested that black glutinous rice and Hom Nil rice were safe and were good sources of antioxidants which might be appreciated by health concerning consumers.
DOI: 10.14457/cu.the.2009.1591
title: Graft copolymerization of methyl methacrylate onto natural rubber latex by microwave induction

description: Natural rubber (NR) is an unsaturated elastomer with excellent mechanical properties. However, NR has poor resistance to oxidation, oil and organic solvents mainly due to its unsaturated chain structure and nonpolarity. These drawbacks have limited its industrial applications. The graft copolymerization via latex phase is one of chemical modification methods to improve NR‟s properties. To enhance the polarity of NR, methyl methacrylate (MMA) was grafted onto the NR in the presence of cumene hydroperoxide (CHPO) and tetraethylene pentamine (TEPA) as redox initiators. However, conventional graft copolymerization generally needs long reaction time (ca. 6-8 h). Due to less energy consumption with faster heating rate, the microwave irradiation was used to induce graft copolmerization of MMA onto NR latex. By comparing with the conventional grafting method at 60%grafting efficiency, the graft copolymerization of MMA onto NR induced by microwave at 100 W required short reaction time (ca. 15 min); whilst, upto 7 h was needed when the conventional method was carried out. The influence of initiator concentration, monomer concentration, microwave power and exposure time on the grafting properties were statistically evaluated by a two level factorial design and univariate experiments. The graft natural rubber (GNR) was characterized by FT-IR and 1H-NMR spectroscopy. Furthermore, the particle morphology of GNR was also characterized by using transmission electron microscope (TEM).
DOI: 10.14457/cu.the.2009.1592
title: Effects of the standardized extract of centella asiatica ECa233 on cognitive deficits induced by B-Amyloid Peptide (25 - 35) in mouse

description: The present study aimed to investigate the effects of a standardized extract of Centella asiatica ECa 233 on cognitive deficits induced by an intracerebroventricular (i.c.v.) injection of β-amyloid peptide 25-35 (Aβ25-35) 9 nmol/mouse into male ICR mice weighing 25-35 g. Seven days after Aβ25-35 injection, we examined their behavioral changes by morris water maze test, step-down test and locomotor activity test. In addition, the level of lipid peroxidation in the cerebral cortex and the neuronal cell density was assessed using a cresyl violet staining. In comparison to sham-operated group, significant impairment of learning and memory, increased levels of brain lipid peroxidation and the loss of neuronal cell in CA1 and CA3 of hippocampus were observed in mice treated with Aβ25-35. The experiment was divided into two protocols. For the 1st protocol, pre-treatment by ECa 233 (10 and 30 mg/kg B.W., p.o., twice daily) was performed for 7 days before the injection of Aβ25-35 and throughout experiment. In the 2nd protocol of post-treatment ECa 233 (10 and 30 mg/kg B.W., p.o., twice daily) was orally given for 15 days after the injection of Aβ25-35. It has been shown that ECa 233 giving either pre-treatment or post-treatment could significantly improve deficits in learning and memory, assessed by Morris water maze test and step-down passive avoidance task, however, ECa 233 did not alter locomotor activity. In addition, ECa 233 could significantly improve increased levels of brain lipid peroxidation and decreased neuronal cell loss of hippocampus in mice receiving Aβ25-35. The results obtained suggested that pre-treatment and post-treatment of a standardized extract of Centella asiatica ECa 233 is effective in ameliorating cognitive deficits induced by an intracerebroventricular injection of Aβ25-35 in mice which is an animal model of Alzheimer's disease. Anti-oxidation property is likely to be at least, in part an underlying mechanism of the results observed. Further investigation should be conducted to determine the other possible mechanisms.
DOI: 10.14457/cu.the.2009.1593
title: Tissue response and biodegradation of hydroxyapatite/gelatin/Thai silk fibroin scaffolds

description: To investigate tissue response, in vitro and in vivo biodegradation of four types of Thai silk fibroin based-scaffolds. Four types of scaffolds including Thai silk fibroin (SF), conjugated gelatin/Thai silk fibroin (CGSF), hydroxyapatite/Thai silk fibroin (SF4) and hydroxyapatite/conjugated gelatin/Thai silk fibroin scaffold (CGSF4) were fabricated by salt-leaching, EDC/NHS crosslinking and alternate soaking techniques. The results on in vitro biodegradation tests showed that the remaining weight of scaffolds after 28 days of incubation in collagenase solution was in the order of CGSF&gt;SF&gt;SF4~CGSF4. The CGSF scaffold was found to have the slowest biodegradability due to the crosslinking by dehydrothermal and EDC/NHS treatment. From in vivo biodegradation tests, all scaffolds could still be observed after 12 weeks of implantation in subcutaneous tissue of Wistar rat. Comparing in vitro and in vivo biodegradation, the CGSF scaffold showed the slowest in vitro degradation while in vivo the slowest degradation was observed in the case of CGSF4 scaffold. The tissue response was evaluated using subcutaneous implantation model following ISO10993-6: Biological evaluations of medical devices. At 2 and 4 weeks of implantation, it was shown that four types of scaffolds were classified as "non-irritant" to "slight irritant", compared to Gelfoam® (control sample). The results indicated the high potential of Thai silk fibroin-based scaffolds for tissue engineering applications.
DOI: 10.14457/cu.the.2009.1594
title: Screening and characterization of arsenite/arsenate oxidizing bacteria from tannery wastes and agriculural soils

description: Ninety-three arsenic resistant bacteria were isolated from 7 tannery waste samples collected from Samutprakan province and 9 agricultural soil samples collected from Nakhonpathom and Petburi Provinces, Thailand by enrichment culture method using medium containing 1.3 mM sodium arsenite. Minimum inhibitory concentration (MIC) of these isolates ranged from 5-&gt;40 mM arsenite and 200- &gt;450 mM arsenate. Highly arsenic resistant bacteria (27 isolates) had minimum inhibitory concentrations (MICs) for arsenite and arsenate of &gt;40 mM and &gt;400 mM, respectively. On the basis of morphological, cultural, physiological and biochemical characteristics; ubiquinone system, and 16S rRNA gene sequence analyses, they were identified as following: nine isolates each of Klebsiella (Groups 1 and 8) and Acinetobacter (Groups 2, 3 and 7), four isolates each of Pseudomonas (Groups 4 and 6) and Comamonas (Group 5), and one isolate of Enterobacter (Group 9). Only one isolate in Group 5, Comamonas sp. A3-3, appeared to have potential for bioremediation due to a capability of oxidizing arsenite to arsenate. The arsenite oxidizing activity was confirmed by an arsenic speciation using a XANES spectroscopic method. An efficiency of the arsenite oxidizing activity determined by modified arsenite-iodine titration method was 65.3%. The arsenite oxidizing strain, Comamonas sp. A3-3, which isolated from agricultural soil grew at 40°C, in the presence of 4.5% (w/v) NaCl and at pH 5 to 11. Major cellular fatty acids were C 16:0, C 18:1 ω7c and C 17:0 CYCLO. Ubiquinone with eight isoprene unit (Q-8) was a predominant ubiquinone. DNA G+C content was 69.6 mol%. Phylogenetic analysis using 16S rRNA gene sequences showed that the strain A3-3 was closely related to C. kerstersii LMG 3475T, C. aquatica LMG 2370T and C. koreensis YH12T with 96.9, 96.8 and 96.4% similarities, respectively. The strain A3-3 could be clearly distinguished from C. kerstersii LMG 3475T and related Comamonas species based on its phenotypic characteristics and phylogenetic position. This strain (A3-3T = NBRC 106524T) could be a novel species in the genus Comamonas, for which the name Comamonas terra is proposed.
DOI: 10.14457/cu.the.2009.1595
title: Effects of standardized extract of centella asiatica ECa 233 on second degree burn wound healing in normal and diabetic rats

description: The purpose of this study was to investigate the effects of standardized extract of Centella asiatica ECa 233 on second degree burn wound healing induced by 90º C hot plate for 10 seconds on the selected area of the back. Male Wistar rats weighing 250-300 g were used and divided into two groups for normal and diabetic rats. In each group, the animals were subdivided into six subgroups as follows : no burn, burn with no treatment (untreated), burn treated with gel base, burn treated with 0.05, 0.1 and 0.5% ECa 233 gel. The wounds were daily treated with 100 mg of the test substances topically. Evaluation of wound healing including a visual observation, an estimation of rate of wound healing, measurement of cutaneous blood flow, lipid peroxidation assay and histopathological observation was made at day 3, 7 and 14 post burning. The result revealed that rate of wound healing in both normal and diabetic rats treated with ECa 233 was significantly different from those observed in their respective untreated and gel base-treated groups. In comparison to their respective control groups, cutaneous blood flow was significantly increased in ECa 233-treated groups at all three time points in diabetic rats whereas it was observed only at day 3 and 7 in normal group. In normal, burn injury significantly increased oxidative stress which was counteracted by ECa 233 throughout experimental period. However, in diabetic, antioxidant property of ECa 233 was evident only on day 14. Visual and histopathological observation, application of ECa 233 seemed to reduce inflammatory cell in normal and diabetic rats though with a lesser extent in the latter group. In addition, the number of hair follicles in ECa 233-treated groups, both in normal and diabetic rats were found to increase on day 3 and 7 post burning. In conclusion topical application of standardized extract of Centella asiatica ECa 233 clearly facilitated burn wound healing in normal and diabetic rats. Shortening of inflammatory process by its anti-inflammatory, increased rate of re-epithelialization and might explain the results observed. Increased of cutaneous blood flow, increased number of hair follicles and anti-oxidation could play role as well. Some other mechanisms await further investigation.
DOI: 10.14457/cu.the.2009.1596
title: Characterization of extended-spectrum β-lactamase and ampc β-lactamase genes in nontyphoidal salmonella clinical isolates in Thailand

description: The production of extended-spectrum β-lactamases (ESBLs) and plasmid-mediated AmpC β-lactamases in nontyphoidal Salmonella are increasingly reported worldwide and pose a serious threat for salmonellosis. Nevertheless, no prevalence data on ESBLs and AmpC β-lactamases in nontyphoidal Salmonella in Thailand have been reported. This study characterized genes encoding ESBLs and plasmid-mediated AmpC β-lactamases and investigated the prevalence of extended-spectrum cephalosporin (ESC) resistance in nontyphoidal Salmonella isolates. A total of 560 nontyphoidal Salmonella isolated from patients during 2005-2007 were included in this study. The resistance rates to cefoxitin, ceftazidime, cefotaxime, and ceftriaxone were 11.79%, 14.64%, 9.46%, and 12.50%, respectively. A total of 119 ESC-resistant isolates were detected for ESBL and AmpC phenotypes. The results showed that 52 isolates (43.70%), 66 isolates (55.46%), and 1 isolate (0.84%) were ESBL producers, AmpC producers, and ESBL and AmpC co-producer, respectively. Screening for the presence of bla genes revealed that 66 isolates (55.46%) carried blaCIT-like followed by 31 isolates (26.05%) with blaCTX-M-9 group, 14 isolates (11.76%) with blaCTX-M-1 group together with blaTEM-like, 7 isolates (5.88%) with blaCTX-M-9 group together with blaTEM-like, and 1 isolate (0.84%) with blaCTX-M-9 group blaTEM-like and blaCIT-like. DNA sequencing analysis of the entire bla genes from representative isolates showed that of the 14 blaCTX-M-1 group, 13 were blaCTX-M-55 and one was blaCTX-M-15 whereas all 10 blaCTX-M-9 group, 22 blaTEM-like, and 10 blaCIT-like were blaCTX-M-14, blaTEM-1, and blaCMY-2, respectively. ISEcp1 was present in the upstream regions of blaCTX-M and blaCIT in all isolates. ISEcp1-mediated -35 and -10 promoter sequences were found in all 34 representative isolates. This is the first report of the prevalence of ESBLs and plasmid-mediated AmpC β-lactamases in nontyphoidal Salmonella isolates in Thailand. Our results showed that the high rate of ESC resistance was attributed to the production of CTX-M-type ESBL and plasmid-mediated AmpC which CTX-M-9 group ESBLs and CIT-type AmpC were the most frequent β-lactamases. This was the first report of CTX-M-14 in S. Choleraesuis and also the first report of co-carrying CMY-2, CTX-M-14, and TEM-1 in nontyphoidal Salmonella.
DOI: 10.14457/cu.the.2009.1597
title: Anti-pathogenic bacterial activities of fractionated venom of king cobra (ophiophagus hannah)

description: This study aimed at measuring the antibacterial activity of the semi-purified fractions isolated from King Cobra venom and investigated the mechanism of action. The protein fractions were isolated from King Cobra venom and designated F1-F7. The F5 showed the highest antibacterial activity and was further concentrated and separated by Sephadex G-75 column to obtain six fractions (F5.1-F5.6). The antibacterial assay showed that F5.1 could inhibit the growth of gram-positive S. aureus and gram-negative E. coli, S. aeruginosa and S. Typhimurium bacteria. The F5.1 showed antibacterial activity against S. aureus with the MIC of 1.8 µg/ml. Its molecular weight determined by SDS-PAGE was 69 kDa. The mechanism of action may be damaging the cytoplasmic membrane, as shown from the scanning electron microscopy. The MIC concentration of F5.1 also showed potent cytotoxicity on human PBMCs cells. The results obtained from this study indicated that the F5.1 had antibacterial activity against the S. aureus through membrane damage, however it was cytotoxic to normal human cells. In conclusion, this study provides basic information on antibacterial effect of the semi-purified F5.1 of King cobra venom. The F5.1 should be further purified or modified to obtain the potential antibacterial compound which will be safe to the normal human cells.
DOI: 10.14457/cu.the.2009.1598
title: Behavior of bone marrow-derived and adipose-derived stem cells on gelatin/chitosan scaffolds for bone tissue engineering

description: งานวิจัยนี้มีวัตถุประสงค์เพื่อที่จะศึกษาอิทธิพลของปัจจัยต่างๆอาทิ ชนิดของกรดที่ใช้เป็นตัวทำละลาย น้ำหนักโมเลกุลของวัสดุชีวภาพ และสัดส่วนในการผสมของวัสดุชีวภาพ ที่มีต่อสมบัติทางกายภาพและทางชีวภาพของโครงเลี้ยงเซลล์ที่ผลิตจากคอลลาเจน เจลาติน และไคโตซาน ในงานวิจัยนี้พบว่า ชนิดของกรดที่ใช้เป็นตัวทำละลายสารละลายคอลลาเจนส่งผลต่อสมบัติทั้งทางกายภาพและทางชีวภาพของโครงเลี้ยงเซลล์คอลลาเจนที่ผลิตได้ โดยโครงเลี้ยงเซลล์คอลลาเจนที่ผลิตจากกรดไฮโดรคลอริกจะมีขนาดรูพรุนที่ใหญ่ มีความสามารถในการทนแรงกดได้ดี และส่งเสริมการยึดเกาะของเซลล์ได้ดี ในขณะที่โครงเลี้ยงเซลล์คอลลาเจนที่ผลิตจากกรดอะซิติก จะมีความพรุนมากกว่า มีความสามารถในการอุ้มน้ำได้ดี และส่งเสริมการแบ่งตัวเพิ่มจำนวนของเซลล์ ดังนั้น การเลือกชนิดของกรดที่เหมาะสมจึงมีส่วนสำคัญที่จะทำให้สามารถผลิตโครงเลี้ยงเซลล์ที่มีสมบัติเหมาะสมสำหรับการใช้งานได้ ในงานวิจัยนี้ยังได้มีการศึกษาถึงการเปลี่ยนแปลงของน้ำหนักโมเลกุลของไคโตซาน และสัดส่วนการผสมระหว่างเจลาตินกับไคโตซาน เพื่อพัฒนาโครงเลี้ยงเซลล์ที่มีสมบัติเหมาะสมสำหรับเป็นต้นแบบในการใช้งานด้านวิศวกรรมเนื้อเยื่อกระดูก โดยพบว่าโครงเลี้ยงเซลล์ที่ผลิตจากเจลาตินและไคโตซานที่มีน้ำหนักโมเลกุลสูง (1,000 กิโลดาลตัล) มีสมบัติทางกายภาพและทางกลที่ดีเยี่ยม แต่ไม่ส่งเสริมกิจกรรมของเซลล์ต้นกำเนิดไขมันและเซลล์ต้นกำเนิดไขกระดูก ทั้งทางด้านการยึดเกาะและการแบ่งตัวเพิ่มจำนวน ในทางตรงข้าม โครงเลี้ยงเซลล์ที่ผลิตจากเจลาตินและไคโตซานที่มีน้ำหนักโมเลกุลต่ำ หรือไคโตโอลิโกแซคคาไรด์ (1.4 กิโลดาลตัล) มีความเหมาะสมสำหรับการยึดเกาะ และการแบ่งตัวเพิ่มจำนวนของเซลล์ต้นกำเนิดทั้งสองชนิด นอกจากนี้ยังพบว่าโครงเลี้ยงเซลล์ที่ผลิตจากเจลาตินและไคโตโอลิโกแซคคาไรด์ดังกล่าว โดยเฉพาะอย่างยิ่งที่สัดส่วนการผสมโดยน้ำหนักของเจลาตินต่อไคโตโอลิโกแซคคาไรด์ 70/30 ส่งเสริมการเปลี่ยนแปลงของเซลล์ต้นกำเนิดไขกระดูกไปเป็นเซลล์กระดูกได้ดี เมื่อเปรียบเทียบกับโครงเลี้ยงเซลล์เจลาติน นอกจากนี้ เมื่อเปรียบเทียบพฤติกรรมของเซลล์ต้นกำเนิดทั้งสองชนิด พบว่าเซลล์ต้นกำเนิดไขมันสามารถแบ่งตัวเพิ่มจำนวนได้เร็วกว่าเซลล์ต้นกำเนิดไขกระดูก ในขณะที่เซลล์ต้นกำเนิดไขกระดูกสามารถเปลี่ยนแปลงไปเป็นเซลล์กระดูกได้ดีกว่าเซลล์ต้นกำเนิดไขมัน ทั้งนี้ไม่ขึ้นอยู่กับชนิดของโครงเลี้ยงเซลล์