Production and characterization of a single-chain Fv antibody–alkaline phosphatase fusion protein specific for ampicillin

Anti-AMP scFv were prepared by cloning variable region genes (VH and VL) from hybridoma cell line which secretes antibodies against AMP, and phoA gene was cloned from Escherichia coli strain K12 chromosomal DNA. The resulting scFv and phoA gene were inserted into the expression vector pBV220 to express the scFv–AP fusion protein in E. coli strain BL21. The puri?ed scFv-AP fusion protein was used to develop an ic-CLEIA method for detection of AMP. The limit of detection (IC₁₅) was 0.11?±?0.004?ng/mL and the IC₅₀ was 0.75?±?0.04?ng/mL, respectively. The assay was 3 times as sensitive as the corresponding ic-ELISA based on the same fusion protein. IC-CLEIA was used to analyse AMP spiked milk samples, and the validation was con?rmed by HPLC. Good correlation between ic-CLEIA and HPLC data was obtained (R^2?=^?0.9934). It indicated that the developed method can apply to effectively monitor food safety.     

镁基植入体植入兔股骨后周围骨微结构变化趋势

目的研究镁基植入体植入兔股骨不同时间点周围骨微结构参数的变化规律。方法将直径2 mm、长7 mm有螺纹及无螺纹的高纯镁(99.99 wt.%)钉植入兔股骨髁,对照组为钻孔组及健康组。在术后8、12、16周进行Micro-CT扫描和分析,得到各组微结构参数,包括:骨质密度(BMD)、骨体积分数(BV/TV)、骨小梁厚度(Tb.Th)、骨小梁数量(Tb.N)、骨小梁分离度(Tb.Sp)。结果 8周时无螺纹镁钉组BMD、BV/TV显著高于健康组,Tb.N显著高于钻孔组与健康组,Tb.Sp显著低于健康组;12周时有螺纹镁钉组BMD、BV/TV、Tb.N显著高于钻孔组与健康组,Tb.Th显著高于健康者,Tb.Sp显著低于钻孔组与健康组;16周时无螺纹镁钉组的BMD、BV/TV、Tb.N显著高于钻孔组与健康组,Tb.Sp显著低于钻孔组与健康组。结论镁基植入体促使周围骨组织的BMD、BV/TV、Tb.Th、Tb.N更高,Tb.Sp更低,说明其骨整合与骨生长状况良好,镁基植入体能有效促进骨再生。研究结果为镁基植入体的骨科临床应用提供理论依据。     

Functional Silica and Carbon Nanocomposites Based on Polybenzoxazines

The preparation of organic/inorganic hybrid materials comprising a polybenzoxazine (PBZ) matrix incorporating silicon‐based species (e.g., polydimethylsiloxane [PDMS], layered silicates [clays], and polyhedral oligomeric silsesquioxanes [POSS]) and carbon‐based materials (e.g., carbon black, carbon fibers, carbon nanotubes, and graphene) has received much attention in recent years because these composites display low water absorption, low surface free energy, low dielectric constants, flame‐retardancy, and excellent thermal and mechanical properties. This short review article describes the chemical and physical approaches that are used to prepare PBZs incorporating silica and carbon nanocomposites. In addition, recent reports of their physical properties are discussed, covering their dielectric constants and dynamic mechanical, thermal, electrical, and surface properties.     

Expression of CD44s, CD44v5, CD44v6 and CD44v7-8 in betel quid chewing-associated oral premalignant lesions and squamous cell carcinomas in Taiwan

Aberrant expression of the cell surface adhesion molecule CD44 and its variant forms has been shown to be associated with the invasive and metastatic potential of cancer cells, and with poor prognosis in several types of cancers. Expression of CD44 standard (CD44s) and variant (CD44v) forms in oral squamous cell carcinoma (SCC), epithelial dysplasia (ED), epithelial hyperkeratosis (EH) and normal buccal mucosa (NBM) have been examined using antibodies to CD44s, CD44v5, CD44v6 and CD44v7-8. Positive CD44s, CD44v5, CD44v6 and CD44v7-8 staining was detected in all the specimens from NBM, EH and ED. Positive staining of CD44s, CD44v5, CD44v6 or CD44v7-8 was detected in 55 (88.7%), 48 (77.4%), 59 (95.2%) and 22 (35.5%) of the 62 SCC specimens, respectively. The positive staining of CD44v7-8 in oral SCC was significantly less than that in NBM ( P <0.01). No significant correlation was found between CD44v7-8 expression and daily or total consumption of betel quids or cigarettes by the SCC patients. The 5-year survival rate for patients with CD44v7-8-positive tumours was significantly higher than that for the CD44v7-8-negative group ( P <0.03). These results indicate that loss of CD44v7-8 expression may be a valuable factor for determining prognosis in oral SCC patients.     

Technical quality of root canal treatment in Taiwan

AIM: To evaluate the current technical quality of root canal treatment (RCT) in Taiwan. METHODOLOGY: A total of 1085 RCT cases, randomly selected from a large sample and representative of the Taiwanese population from April to September 2000, were evaluated by eight endodontic specialists. The qualitative evaluation of RCT cases was based on two variables: length of the root filling and density of the obturation. A root canal with both adequate filling length (the apical termination of the root filling within 2 mm of the radiographic apex) and complete obturation (no lateral or apical canal lumen visible in the apical one-third of the root canal) was defined as having good-quality endodontic work (GQEW). A tooth was defined as having a GQEW when all its canals were categorized as GQEW. RESULTS: From a total of 1867 root canals, overfilling occurred in 235 (12.6%), adequate filling length in 1152 (61.7%), underfilling in 466 (25.0%) and no filling in 12 (0.6%). Of the 1867 root canals, 710 (38.0%) demonstrated complete obturation and 1157 (62%) demonstrated incomplete obturation. GQEW was found in 650 (34.8%) root canals and 329 (30.3%) teeth. The percentage of teeth with GQEW in hospital cases (38.1%) was significantly greater (P < 0.001) than that in private clinic cases (24.3%). In addition, the frequency of teeth with GQEW in the anterior teeth (40.4%) or in the premolars (33%) was significantly greater (P < 0.001) than that in the molars (18.4%). CONCLUSIONS: Approximately 70% of the teeth receiving RCT in Taiwan were either of inadequate filling length or sealing density.     

Nitric oxide promotes the progression of periapical lesion via inducing macrophage and osteoblast apoptosis

This study aimed to elucidate the modulation by nitric oxide (NO) of the apoptosis of macrophages and osteoblasts, the essential cellular components in the development of periapical lesions. Lipopolysaccharide (LPS) induced prominent nitrite synthesis in J774 mouse macrophage cell lines. Exposure to LPS induced obvious apoptosis in J774 cells, whereas transient transfection with murine inducible nitric oxide synthase (iNOS), small interfering RNA (siRNA) diminished this effect. Tumor necrosis factor-alpha (TNF-alpha) and S-nitroso-N-acetyl-DL-penicillamine (SNAP) (a NO donor) triggered apoptosis in UMR-106 rat osteoblastic cell lines and a synergistic effect was noted when TNF-alpha and SNAP were added to the medium together. Administration of siRNAs for c-Fos and c-Jun: components of activator protein-1 (AP-1) and transforming growth factor-beta1 attenuated the combined effect markedly. Terminal deoxynucleotidyl transferase-mediated nick end-labeling (TUNEL) stain in a rat model of induced periapical lesion showed positive apoptotic signals in macrophages and osteoblasts. Administration of N(G)-monomethyl-l-arginine markedly diminished the extent of bone loss and the amounts of apoptotic macrophages and osteoblasts. In conclusion, NO mediates LPS-stimulated apoptosis of macrophages. It also induces osteoblast apoptosis and augments the pro-apoptotic effect of cytokines. Inhibition of NO synthesis in vivo attenuates apoptosis and the size of periapical lesions. Taken together, these results suggest that NO may promote the progression of periapical lesion by inducing the apoptosis of macrophages and osteoblasts.     

Endovascular therapy in the emergent management of intractable hemorrhage associated with head and neck neoplasms

Oral Radiology - To evaluate the feasibility, safety, and efficacy of endovascular interventions in the emergent management of life-threatening hemorrhage associated with head and neck neoplasm....     

Modulation of host matrix metalloproteinases by bacterial virulence factors relevant in human periodontal diseases

OBJECTIVE: Bacterial pathogens involved in periodontal diseases exert a part of their destructive effect by triggering and inducing host cells to elevate their secretion of matrix metalloproteinases (MMPs). Pathogen-secreted phospholipase (PLC) is one bacterial product that may trigger this host response. The roles of exogenous PLC leading to the release, secretion and expression of MMPs by peripheral blood neutrophils (PMNs), cultured epithelial cells of human gingiva and porcine periodontal ligament were investigated. Also the activities of PLC in the diseased and healthy gingival sulcular fluid (crevicular fluid, GCF) and molecular forms of gelatin-ases present in dental plaque were investigated. MATERIALS AND METHODS GCF, salivary and dental plaque samples were analyzed for PLC and proteinase activities. The abilities of PLC to induce PMNs and oral epithelial cells to release and express their MMPs were examined by specific functional, immunological and molecular biology means. RESULTS: PMN-derived MMPs were found to predominate in periodontitis GCF and plaque, and PLC activities were higher in GCF of adult periodontitis patients than in healthy controls. Purified bacterial PLC (1 mU ml^-I) efficiently induced PMN degranulation. PLC also induced MMP expression in the cultured epithelial cells. The strongest response was seen in MMP-9 and less in MMP-2. The induction was dose-dependent in the range of 0.I-1.0 U ml^-1 PI-PLC, and quiescent cultures were more responsive than proliferating ones. PLC induction of MMPs was polar, with increased levels of MMP-9 in the apical region and increased MMP-2 levels secreted in the basal direction. Northern analysis showed a strong increase in mRNA levels of MMP-9 and a smaller increase for MMP-2 and MMP-I. In the second part of the study we investigated the molecular forms of the released MMPs during periodontitis. In bacterial plaque of periodontitis patients the MMP-9 were found to be converted into lower molecular weight forms. Isolated proteinase from Porphyromonas gingivalis (ATCC 33277) was able to convert human proMMPs to their active forms. CONCLUSION: Bacterial PLC may induce degranulation of PMN MMPs and increase MMP expression in oral epithelial cells. The released proteases can be converted into active form by the proteases of plaque bacteria. Thereby, the pathogenic oral bacteria may indirectly participate in the destruction of periodontal tissues.     

盐酸咪达唑仑镇静药在阻生智齿拔除术中应用的临床观察

目的观察马来酸咪达唑仑（midazolam HCl）静脉输注提高下颌阻生智齿拔除时患者舒适度的效果。方法50例双侧下颌阻生智齿拔除难度基本相同的患者，采用自身对照设计，一侧采用盐酸咪达唑仑低流量（平均流量0．042±0．010mg·kg^-1）静脉输入，另一侧空白对照。结果试验组焦虑视觉模拟量表（visual analogue scale，VAS）平均得分21．4±12．2mm，疼痛VAS平均得分（6．92±9．50）mm，与对照组（35．9±18．2）mm；（16．4±12．4mm）比较，差异有统计学意义（P=0．000；P=0．000）。结论在拔除阻生智齿时，对轻度恐惧的患者应用盐酸咪达唑仑镇静，可以显著提高患者的舒适度。     

Effect of mechanical loading on electrical conductivity in porcine TMJ discs

The objective of this study was to examine the impact of mechanical loading on solute transport in porcine temporomandibular joint (TMJ) discs using the electrical conductivity method. The electrical conductivity, as well as ion diffusivity, of TMJ discs was determined under confined compression with 3 strains in 5 disc regions. The average electrical conductivity over the 5 regions (mean ± SD) at 0% strain was 3.10 ± 0.68 mS/cm, decreased to 2.76 ± 0.58 mS/cm (-11.0%) at 10% strain, and 2.38 ± 0.55 mS/cm (-22.2%) at 20% compressive strain. Correspondingly, the average relative ion diffusivity (mean ± SD) at 0% strain was 0.273 ± 0.055, decreased to 0.253 ± 0.048 (-7.3%) at 10% strain, and 0.231 ± 0.048 (-15.4%) at 20% compressive strain. These results indicated that compressive strain impeded solute transport in the TMJ disc. Furthermore, our results showed that the transport properties of TMJ discs were region-dependent. The electrical conductivity and ion diffusivity in the anterior region were significantly higher than in the posterior region. This regional difference is likely due to the significant differences of tissue hydration between these 2 regions. This study provides important insight into the electrical and solute transport behaviors in TMJ discs under mechanical loading and aids in the understanding of TMJ pathophysiology related to tissue nutrition.