Publications by authors named "Xin-Zhu Yi"

14 Publications

  • Page 1 of 1

Occurrences and Characterization of Antibiotic-Resistant Bacteria and Genetic Determinants of Hospital Wastewater in a Tropical Country.

Antimicrob Agents Chemother 2016 12 21;60(12):7449-7456. Epub 2016 Nov 21.

NUS Environmental Research Institute (NERI), National University of Singapore, Singapore

Wastewater discharged from clinical isolation and general wards at two hospitals in Singapore was examined to determine the emerging trends of antibiotic resistance (AR). We quantified the concentrations of 12 antibiotic compounds by analysis using liquid chromatography-tandem mass spectrometry (LC-MS/MS), antibiotic-resistant bacteria (ARB), the class 1 integrase gene (intI1), and 16 antibiotic resistance genes (ARGs) that confer resistance to 10 different clinically relevant antibiotics. A subset of 119 antibiotic-resistant isolates were phylogenetically classified and tested for the presence of ARGs encoding resistance to β-lactam antibiotics (bla, bla, bla, bla), amikacin [aac(6')-Ib], co-trimoxazole (sul1, sul2, dfrA), ciprofloxacin (qnrA, qnrB), and the intI1 gene. Among these resistant isolates, 80.7% were detected with intI1 and 66.4% were found to carry at least 1 of the tested ARGs. Among 3 sampled locations, the clinical isolation ward had the highest concentrations of ARB and the highest levels of ARGs linked to resistance to β-lactam (bla), co-trimoxazole (sul1, sul2, dfrA), amikacin [aac(6')-Ib], ciprofloxacin (qnrA), and intI1 We found strong positive correlations (P < 0.05) between concentrations of bacteria resistant to meropenem, ceftazidime, amikacin, co-trimoxazole, and ciprofloxacin and abundances of bla, aac(6')-Ib, sul1, sul2, dfrA, qnrA, and intI1 genes.
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http://dx.doi.org/10.1128/AAC.01556-16DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5119029PMC
December 2016

Comparisons of condylar movements with the functional occlusal clutch and tray clutch recording methods in CADIAX system.

Int J Oral Sci 2010 Dec;2(4):208-14

Department of Oral Anatomy and Physiology, West China College of Stomatology, Sichuan University, Chengdu, China.

Aim: The purpose of this study is to compare the effects of the two clutches on recording the condylar movement.

Methodology: Ten subjects (6 women, 4 men; mean age 25.4 years) participated in the study. The mandibular movement, sagittal condylar inclination angle, and transversal condylar inclination angle of each subject were recorded with the CADIAX using the two clutches, respectively. The characteristics of the tracings of the protrusion, opening, and mediotrusion were analyzed with the t-test statistics at a = 0.05 level. The Kappa values were calculated for an assessment of the congruence of the tracings.

Results: The results showed that the contour, direction, and dimension of the tracings in the two clutches were approximately same, but the tracings determined by the functional occlusal clutch were more regular and congruent. In the group segment recorded with the tray clutch, opening/closing paths of one subject showed crossed and time curves of three subjects appeared peak-like changes of velocity, but none were statistically different (P>0.05).

Conclusion: The research suggests that the functional occlusal clutch should be preferred in the evaluation of the mandibular function, as the tracings with the tray clutch are more likely to produce false positive results.
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http://dx.doi.org/10.4248/IJOS10071DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3498997PMC
December 2010

The expression profile of microRNAs in a model of 7,12-dimethyl-benz[a]anthrance-induced oral carcinogenesis in Syrian hamster.

J Exp Clin Cancer Res 2009 May 13;28:64. Epub 2009 May 13.

Department of Oral Maxillofacial Surgery, West China College of Stomatology, Sichuan University, No,14, Sec,3, Renminnan Road, Chengdu, Sichuan 610041, PR China.

Background: Non-coding RNA molecules, such as microRNAs, may play an important role in carcinogenesis. Recent studies have indicated that microRNAs are involved in initiation and progression of various malignancies. However, little work has been done to compare the microRNA expression patterns in oral cancer. In this study, we constructed an animal model of oral squamous cell carcinoma to investigate expression profiles of microRNAs in oral carcinogenesis.

Methods: The animal model of oral squamous cell carcinoma was conducted by tri-weekly (Monday, Wednesday, and Friday) painting with 5% DMBA in acetone. Six Syrian hamsters, including three from the treated group and three from the control group, were used as a training group for microRNA microarray analysis. All microarray data were analyzed by Significance Analysis of Microarrays (SAM) and CLUSTER 3.0 software, and this result was further confirmed by qRT-PCR assay.

Results: Seventeen microRNAs were differentially expressed in oral squamous cell carcinoma. Five microRNAs (hsa-miR-21, hsa-miR-200b, hsa-miR-221, hsa-miR-338, and mmu-miR-762) were significantly upregulated and twelve microRNAs (hsa-miR-16, hsa-miR-26a, hsa-miR-29a, hsa-miR-124a, hsa-miR-125b, mmu-miR-126-5p, hsa-miR-143, hsa-miR-145, hsa-miR-148b, hsa-miR-155, hsa-miR-199a, and hsa-miR-203) were down-regulated in cancer tissues. The expression levels of hsa-miR-21 and hsa-miR-16 seen with Stem-loop qRT-PCR were also seen in microarray analysis in all samples.

Conclusion: Our findings identified specific microRNA expression in oral squamous cell carcinoma and suggested that microRNAs have a role in oral carcinogenesis.
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http://dx.doi.org/10.1186/1756-9966-28-64DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2687417PMC
May 2009

[Roles of matrix metalloproteinases and tissue specific inhibitors of metalloproteinases in dentinogenic ghost cell tumor and ghost cell odontogenic carcinoma].

Zhonghua Kou Qiang Yi Xue Za Zhi 2008 Dec;43(12):756-60

Department of Oral Pathology, West China College of Stomatology, Sichuan University, Chengdu, China.

Objective: To investigate the roles of matrix metalloproteinases (MMP) and tissue inhibitors of metalloproteinases (TIMP) in dentinogenic ghost cell tumor (DGCT) and ghost cell odontogenic carcinoma (GCOC).

Methods: The expressions of MMP-2, MMP-9, MMP-14, TIMP-1 and TIMP-2 were examined in 15 DGCT cases and 9 GCOC cases by immunohistochemistry. Their mRNA expression in one DGCT case and one GCOC case were investigated by RT-PCT.MMP-2 and MMP-9 protein activities in the two cases were analyzed by gelatin zymography.

Results: MMP-9 and TIMP-1 expressions elevated greatly in GCOC, and there was a significant difference (P < 0.05) in TIMP-1 expression between GCOC and DGCT.Pro-MMP-9, MMP-9 activated form, pro-MMP-2, and MMP-2 activated forms were detected in the GCOC case, while pro-MMP-9 and MMP-9 activated form were very faint in the DGCT case. The mRNA level of MMP-9 elevated obviously in the GCOC case, which was similar to that of TIMP-1.

Conclusions: The elevated expression of MMP-9 and TIMP-1 may influence the behaviour of GCOC.
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December 2008

[Effect of estrogen on heat shock protein 70 expression in rat masseter muscle].

Hua Xi Kou Qiang Yi Xue Za Zhi 2008 Oct;26(5):560-2

State Key Laboratory of Oral Diseases, Sichuan University, Chengdu 610041, China.

Objective: To investigate the effect of estrogen on heat shock protein (HSP) 70 expression in rat masseter muscle.

Methods: Sixty twelve-week-old female Sprague-Dawley rats were randomly divided into three groups: Sham surgery group (control group), ovariectomy group (OVX group), ovariectomy with estradiol valerate replacement treatment group (OVX/EV group). Half of the animals were sacrificed at 4 and 8 weeks respectively, then the masseter muscle was removed. Immunohistochemistry (IHC) method was employed to study the HSP70 expression in masseter muscle.

Results: Compared to control group and OVX/EV group, the expression of HSP70 was significantly lower at 8 weeks in OVX group (P < 0.05). There were no significantly difference between the HSP70 expression of control group and that of OVX/EV group.

Conclusion: Estrogen may affect HSP70 expression in rat masseter muscle, and estrogen replacement therapy may prevent HSP70 reduction.
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October 2008

[Effects of 17beta-estradiol on the intracellular calcium of masticatory muscles myoblast in vitro].

Hua Xi Kou Qiang Yi Xue Za Zhi 2007 Dec;25(6):611-3

State Key Laboratory of Oral Diseases, Sichuan University, Chengdu 610041, China.

Objective: To observe the effects of 17beta-estradiol on the intracellular calcium of masticatory muscles myoblast.

Methods: Myoblasts from maxillofacial skeletal muscle of one week old female Sprague-Dawley rats were cultured. Fluo-4-AM as the Ca2+ indicator and the laser confocal microscope system were used to observe the effects of estrogen on the cytoplasmic Ca2+ concentration in the normal pH condition and the acid condition (pH = 6.7).

Results: In the normal pH condition, when 17beta-estradiol (10(-9), 10(-8), 10(-7) mol/L) were added to cells cytoplasmic Ca2+ immediately increased then decreased right away, and in the end came into a new Ca2+ homeostasis in the base line. In the acid condition, 17beta-estradiol (10(-9), 10(-8), 10(-7) mol/L) made the cytoplasmic Ca2+ decreased immediately then came into a new Ca2+ homeostasis under the base line.

Conclusion: The results suggest that estrogen may maintain the skeletal cytoplasmic Ca2+ concentration in a lower level and reduce the cytoplasmic Ca2+ accumulation to keep the normal functions of masticatory muscles myoblast.
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December 2007

[Exclusion of candidate genes in a family with amelogenesis imperfecta].

Hua Xi Kou Qiang Yi Xue Za Zhi 2007 Jun;25(3):249-52

Key Laboratory of Oral Biomedical Engineering of Ministry of Education, Sichuan University, Chengdu 610041, China.

Objective: To localize the gene (s) responsible for autosomal dominant hypocalcified amelogenesis imperfecta in a Chinese family.

Methods: A Chinese family which was diagnosed as autosomal dominant hypocalcified amelogenesis imperfecta (AD) was studied. Venous blood from nineteen family members was collected and genomic DNA was extracted from the blood. Eight short tandem repeats (STRs) spanning five hereditary AI candidate genes were selected and linkage analysis between the genetic markers and the disease loci was performed.

Results: Genotype of the eight STRs were acquired, the linkage analysis result can not support that the gene for AI pedigrees was linked to ENAM, AMBN, TUF1, KLK4 or MMP-20.

Conclusion: The results can not support all proposed candidate gene regions as causal for autosomal dominant hypocalcified AI in this family. These linkage findings provide further evidence for genetic heterogeneity among families with autosomal dominant AI and indicate that, at least, some forms of autosomal dominant AI are not caused by a gene in the five most commonly reported AI candidate genes.
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June 2007

[Evaluation of a model of temporomandibular disorders established by transzygomatic arch traction of the mandibular ramus in rabbits].

Zhonghua Kou Qiang Yi Xue Za Zhi 2006 Dec;41(12):755-6

Department of Oral Anatomy and Physiology, College of Stomatology, Nanjing Medical Science University, Nanjing 210029, China.

Objective: To evaluate a model of temporomandibular disorders established by transzygomatic arch traction of the mandibular ramus in rabbits.

Methods: Fifteen adult New Zealand rabbits were subjected to traction in the postero-superior direction unilaterally using elastic force and six rabbits used as the control. Histopathologic change of the disc, joint space and cartilage was observed through Hematoxylin and Eosin staining.

Results: Anterior disc displacement or disc deformity in four experimental rabbits was observed on the traction side 2 weeks after operation. At 4 weeks, fibrous adhesions in joint compartment were found in five experimental rabbits. The condyles or articular eminences of some experimental rabbits showed irregularities on the cartilage surface. In the 6 th week, bad disc deformity in four rabbits and severe fibrous adhesions in five rabbits was observed on the traction side, and subchondralbone and calcified cartilage became irregular. In control group, All articular structures were normal.

Conclusions: A animal model of temporomandibular disorders can be established by transzygomatic arch traction of the mandible.
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December 2006

[Permeability research of human temporomandibular joint disc and cartilage].

Hua Xi Kou Qiang Yi Xue Za Zhi 2006 Jun;24(3):254-6

Beijing Research Institute of Traumatology and Orthopedics, Beijing 100035, China.

Objective: To measure the permeability of human temporomandibular joint (TMJ) disc and cartilage to provide basic parameter for oral biomechanics and tissue engineering, and analyze its mechanisms of pathology and load-release.

Methods: Confined compression method was used to measure the permeability (k value) of four cadavers' TMJs, which were sampled into three parts: disc, condyle and glenoid fossa with different diameters (2 mm, 3 mm and 4 mm). All 128 samples were tested with correspond diameter indenter.

Results: Larger the sample diameter was, higher the k value became. The highest k value appeared in the disc while the lowest appeared in glenoid fossa.

Conclusion: In normal condition, TMJ can suffer huge load by decreasing its permeability. Disc is weakest for the higher permeability, it's easy-damaged region is an initiated factor of TMJ disease.
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June 2006

[Regulation of PTHrP in proliferation and differentiation of chondrocytes of condyle in fetal mouse].

Hua Xi Kou Qiang Yi Xue Za Zhi 2006 Jun;24(3):206-9

Dept. of Oral Anatomy and Physiology, College of Stomatology, Nanjing Medical Science University, Nanjing 210029, China.

Objective: To investigate the regulatory mechanism of parathyroid hormone-related protein (PTHrP) in proliferation and differentiation of chondrocytes of condyle in fetal mouse.

Methods: Chondrocytes of condyle in fetal mouse were separated and cultured in vitro, the influence of PTHrP on proliferation and differentiation was observed.

Results: After two weeks' culture in 0.01 nmol/L, 0.1 nmol/L, 1 nmol/L, 10 nmol/L human PTHrP, there was significant difference in the number of cartilage nodule formed between experiment group and control group (P<0.05), and there was no significant difference in 0.01 nmol/L group (P>0.05). Alkaline phosphatase (ALP) activity was significantly intensified in experiment group and control group (P<0.05). Meanwhile, it was found that this function of promotion was lessened after anti-PTHR antibody used.

Conclusion: It can be seen that PTHrP, via its receptor, can promote proliferation and differentiation of chondrocytes of condyle, which resemble its modulation mechanism in epiphyseal growth plate cartilage intramembrane in mandibule.
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June 2006

[Effect of Fränkel function regulator on the condylar and mandibular positions of patients with class II malocclusion].

Hua Xi Kou Qiang Yi Xue Za Zhi 2005 Apr;23(2):122-5

Dept. of Orthodontics, West China College of Stomatology, Sichuan University, Chengdu 610041, China.

Objective: To determine the positional changes of condyle and mandible in children treated successfully with Fränkel function regulator.

Methods: 30 Angle's class II patients including 15 boys and 15 girls treated with Fränkel function regulator were selected. Superimposition of the pretreatment and posttreatment lateral cephalograms of all the patients was done on the stable bone structure of the anterior cranial base and mandible. Cartesian coordinate system was used to measure the positional changes of condyle and mandible over time by computer.

Results: There was significant inferior displacement of condyle, gonion and pogonion after treatment with reference to stable bone structure of anterior cranial base. Anterior displacement of pogonion in boys was also significant. There was significantly superior and posterior displacement of condyle and posterior displacement of gonion after treatment with reference to stable bone structure of mandible.

Conclusion: Fränkel function regulator can stimulate condylar growth and do favor to mandibular remolding.
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April 2005

[The distribution of collagen I, II, X and alkaline phosphatase in the development of condylar cartilage of fetal mouse mandible].

Hua Xi Kou Qiang Yi Xue Za Zhi 2005 Feb;23(1):11-3

Key Laboratory of Oral Biomedical Engineering Ministry of Education, Sichuan University, Chengdu 610041, China.

Objective: The purpose of this study was to investigate the distribution of collagen I, II , X, alkaline phosphatase (ALP) and their roles during initiation of condylar cartilage of the fetal mouse.

Methods: Coronary sections of mandible of mouse embryo aged from 14th to 18th day were studied under light microscope after stained by immunohistochemical method with antibody of types I, II, X collagen and ALP.

Results: On the 14th day of mouse embryo, it was found that mesenchymal cells condensation continuous with the periosteum. Type I collagen and ALP were positive behind the terminal of the ossifying mandibular periosteum where future condylar will form. On the 15th day, positive staining for types I, II collagen was found in mesenchymal cells around hypertrophic cells and type X collagen was detected in hypertrophic cells. ALP was positive in both mesenchymal cells and hypertrophic cells. On the 16th day, type I collagen was observed from periosteal osteogenic cells and mesenchymal cells of the fibrous cell layer to the upper hypertrophic cell layer while Type II collagen was restricted from the lower polymorphic cell layer to the bottom of the hypertropic cell layer. Type X collagen was positive in the hypertrophic cell layer. ALP was positive in periosteal osteogenic cells and hypertrophic chondral cells, but not in the polymorphic cell layer.

Conclusion: Development of condylar cartilage is different from that of limb bone. Types I, II, X collagen are expressed in the condylar chondrocyte on the early stage of endochondral ossification. The histology evidence supports the conjecture that condylar cartilage is derived from differentiated mesenchymal cells of the preperiosteum or periosteum of the mandible where ALP is positively expressed.
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February 2005

[The correlation between neck lymphy node metastasis and matrixmetalloproteinase-2 expression at the invasive tumor front of oral squamous cell carcinomas].

Hua Xi Kou Qiang Yi Xue Za Zhi 2004 Apr;22(2):106-8

Dept. of Oral Pathology, West China College of Stomatology, Sichuan University, Chengdu 610041, China.

Objective: To explore the correlation between neck lymph node metastasis and matrix metalloproteinase-2 expression at the invasive tumor front of oral squamous cell carcinomas(OSCC).

Methods: Immunohistochemistry LsAB technique was used to observe the expression of MMP-2 at the invasive tumor front and center of OSCC, and the correlation between the expression of MMP-2 in OSCC and neck lymph node metastasis were respectively analyzed by statistics.

Results: The results demonstrated that MMP-2 existed in all 71 cases, which the expression of MMP-2 at the OSCC front was more significant than that of MMP-2 at the OSCC center (P < 0.01), and related to neck lymph node metastasis (P < 0.05).

Conclusion: The expression of MMP-2 at the OSCC front could be considered as an index of judging the present of neck lymph node metastasis of OSCC.
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April 2004

[Infection of human papillomavirus in oral benign epithelial proliferation in children].

Zhonghua Kou Qiang Yi Xue Za Zhi 2003 Nov;38(6):426-8

Department of Pathology, West China School of Stomatology, Sichuan University, Chengdu 610041, China.

Objective: To investigate the presence of HPV infection of oral mucosa proliferative lesions in children and determine the associations of HPV types with oral mucosa lesions in children.

Methods: Immunohistochemical method and in situ hybridization techniques were applied to detect human papillomavirus (HPV) infection in biopsies taken from clinical lesions in oral mucosa of 30 children.

Results: The most frequent lesions detected were SCP (66.7%), followed by CA and FEH. The HPV viral antigen was present in 73.3% (22/30) of the oral benign epithelial proliferative lesions in children. A high frequency HPV was found in CA (6/6) and SCP (15/20) by means of IHC. In the ISH positive case, high risk HPV 16/18 was observed in 77.3% (17/22).

Conclusion: This study demonstrates a high prevalence of HPV infection in children's oral mucosa proliferative lesions, and high-risk HPV16/18 are predominant in children's oral mucosa proliferative lesions.
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November 2003
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