嗅鞘细胞移植治疗免疫性脑脊髓炎：有免疫学排斥现象吗？

目的：研究嗅鞘细胞（OECs）的免疫原性及移植实验性免疫性脑脊髓炎（EAE）后颈淋巴系统的反应。方法：用新生ICR小鼠嗅球培养出OECs, 流式细胞术（FCM）检测其表面主要组织相容性抗原I、II类（MHC-I、MHC-II）表达情况。将经荧光染料CFSE标记OECs悬液或PBS注入EAE大鼠或正常大鼠的侧脑室,收集移植7天后颈部淋细胞,FCM检测CFSE+、抗原提呈细胞标志物CD83+及CFSE+CD83+的表达率,混合淋巴细胞培养检测淋巴细胞增殖率（PI）。结果：OECs高表达MHC-I (78.4±4.45%),中表达MHC-II(43.2±2.98%)。移植实验显示移植OECs的EAE大鼠颈部淋巴结中CD83+（3.83±0.03%）、CFSE+（2.47±0.05%）及CD83+CFSE+（1.98±0.04%）检出率及OECs诱导的PI值（1.32±0.06）均高于对照组或正常大鼠（P<0.05）。同时,PBS注射的EAE大鼠,较正常大鼠亦有较高的CD83+检出率（3.12±0.04%）及PI值（1.20±0.03）（P<0.05）。结论： OECs高表达的MHC分子提示OECs有免疫原性,移植后局部淋巴系统可出现针对OECs的抗原引流、提呈及T细胞的活化,进一步分析提示这种免疫反应的启动依赖于EAE的炎性环境,而OECs移植则加重这一过程。     

中国雪蛤酶解液预防去卵巢大鼠骨质疏松

背景：以往研究发现雪蛤具有预防绝经后相关疾病的作用,但是否具有预防绝经后骨质疏松的功效有待于深入研究。 目的：验证雪蛤酶解液对去卵巢大鼠骨质疏松的预防作用。 方法：健康成年Wistar大鼠72只,按随机数字表法分为6组,每组12只。假手术组大鼠不切除卵巢仅切除卵巢周围部分脂肪,其余各组均切除卵巢造成骨质疏松模型。于造模后第7天开始,各组等容灌胃,连续12周。假手术组和模型组每日灌胃等量蒸馏水;普雷马林组每日灌胃387.8 g/L普雷马林(结合雌激素片)悬浮液6. 67 g/(kg•d);67.0,26.8,13.4 g/(kg•d) 蛤士蟆酶解液组每日分别按相应剂量灌胃。每个月测定食物利用率;实验12周末时,处死大鼠后取子宫,测定子宫质量;取左、右侧股骨和腰椎骨,双能X射线骨密度仪测定骨密度;电感偶合等离子体直读光谱仪测定骨钙、磷含量;脱脂、灰化后测定骨干质量、灰质量。 结果与结论：在4组干预组中,67.0 g/(kg•d)蛤士蟆酶解液组和普雷马林组的食物利用率最低(P < 0.05);在各切卵巢组中,普雷马林组的子宫质量最重(P < 0.05);26.8 g/(kg•d) 蛤士蟆酶解液和普雷马林可以延缓切卵巢大鼠股骨骨密度的下降(P < 0.05);67.0,26.8,13.4 g/(kg•d)蛤士蟆酶解液组骨钙和骨磷与模型组比较均有明显提升(P < 0.05),与普雷马林组差异无显著性意义(P > 0.05)。提示雪蛤酶解液对去卵巢大鼠的骨质疏松具有预防作用,其疗效与结合雌激素片相当,且对子宫增生的不良反应低于结合雌激素片。     

兔自体颌下腺部分移植模型的建立

背景：近年来临床上应用血管化自体颌下腺移植治疗重症角结膜干燥症取得了较好的治疗效果,但术后会出现泪溢的并发症,需要再次甚至多次手术切除部分腺体以减轻泪溢的症状。为减少自体颌下腺移植后出现的泪溢并发症,自体颌下腺部分移植是否可行尚待验证。 目的：通过建立兔颌下腺部分移植的动物实验模型,探讨兔颌下腺部分移植的可行性。 方法：取家兔左侧颌下腺2/3,应用显微外科血管吻合技术移植于颞侧皮下间隙,14 d后取出,苏木精-伊红染色观察其病理变化。 结果与结论：15只移植腺体存活兔中7只移植的颌下腺病理切片示正常,腺体正常度在30%以上的6只,腺体正常度在30%以下的2只。结果显示87%兔部分颌下腺移植后,保留了30%以上正常的腺体结构。兔部分颌下腺移植模型构建具可行性,该结果对采用自体颌下腺部分移植治疗干眼症的手术具有参考价值。 关键词：自体移植;颌下腺;兔;动物模型;移植动物模型     

定期文献报告会在血管神经病学研究生培养中的体会

目的 探讨定期文献报告会在血管神经病学研究生临床教学中的效果。      

碱性成纤维细胞生长因子对体外培养人牙髓细胞增殖和迁移的影响

目的研究碱性成纤维细胞生长因子（basic fibroblast growth factor,bFGF）对体外培养人牙髓细胞增殖、迁移活性的影响。方法以常规组织块培养法体外获得人牙髓细胞,实验组分别加入终浓度为1.0、5.0、10.0和50.0ng/ml的bFGF,对照组仅加入等量的空白培养基,采用CCK-8法分别测定450nm下各组光吸收度A值,研究bFGF对牙髓细胞增殖活性的影响;应用Transwell小室培养法,研究bFGF对牙髓细胞迁移活性的影响。结果与对照组相比,bFGF在1.0～50.0ng/ml浓度下可促进牙髓细胞的增殖（P〈0.05）,bFGF最低显效浓度为1.0ng/ml,最佳显效浓度为10.0ng/ml。bFGF在1.0～50.0ng/ml浓度下诱导细胞迁移（P〈0.05）。结论 bFGF可诱导体外培养人牙髓细胞的增殖和迁移,在牙髓牙本质复合体修复中可能发挥重要作用。     

碱性成纤维细胞生长因子缓释系统促进颌面部骨折愈合的实验研究

目的：探讨碱性成纤维细胞生长因子（basic fibroblast growth factor,bFGF）缓释系统加速兔下颌骨骨折愈合的作用和机理。方法：采用32只成年新西兰兔制备下颌骨线形骨折模型,实验组骨折处分别覆盖bFGF/胶原复合膜和bFGF/藻酸钙凝胶,对照组仅涂布50μg bFGF,空白对照组未加任何生长因子和缓释系统。术后2、4、8、12周行组织学和免疫组化检查。结果：bFGF缓释系统实验组骨折处新骨形成明显快于对照组,bFGF在骨折愈合8周后仍有高强度表达,骨折区有大量血管生成;空白对照组2周时bFGF有较弱的表达,4周后bFGF的表达不明显。bFGF/胶原复合膜组和bFGF/藻酸钙凝胶组实验组间成骨速度、血管形成量和bFGF的表达情况无显著差异,胶原的降解速度快于藻酸钙凝胶。结论：bFGF缓释系统能在骨折愈合期间持续释放bFGF生长因子,并加快下颌骨骨折的愈合速度,缩短骨折临床愈合时间,具有理想的临床应用前景。     

Quality of root canal treatment performed by undergraduate dental students at the University of Khartoum, Sudan

The aim of the present study was to evaluate the quality of root canal treatment performed by undergraduate dental students at the University of Khartoum. Assessment was by examination of periapical radiographs of completed endodontically treated teeth, performed by undergraduate dental students. A total of 166 postoperative periapical radiographs compromising 265 roots were included. The quality of endodontic treatment was examined in relation to the length of the root filling in relation to the radiographic apex, the density of the obturation according to presence of voids and the taper of root canal fillings. Adequate length of the root filling was found in 34.7% of the maxillary teeth and in 10.9% of mandibular teeth in this study. Adequate density was found in 38.87% of maxillary and 16.98% of mandibular teeth and appropriate taper was found in 40% of maxillary and 16.6% of mandibular teeth. Overall 24.2% in all evaluated teeth were found to have a root filling of an acceptable quality. This result may be because of insufficient preclinical endodontic training of the students' operators or because of the introduction of students to endodontic clinical practice late in their program.     

Topical and intermittent application of parathyroid hormone recovers alveolar bone loss in rat experimental periodontitis

Tokunaga K, Seto H, Ohba H, Mihara C, Hama H, Horibe M, Yoneda S, Nagata T. Topical and intermittent application of parathyroid hormone recovers alveolar bone loss in rat experimental periodontitis. J Periodont Res 2011; 46: 655–662. © 2011 John Wiley & Sons A/S Background and Objective: Periodontitis is characterized by periodontal tissue inflammation and alveolar bone loss. The intermittent administration of parathyroid hormone (PTH), a major regulator of bone remodeling, has been demonstrated to stimulate osteoblastic activity. Although the systemic administration of PTH has been reported to protect against periodontitis‐associated bone loss, the effect of the topical administration of PTH is unclear. In this study, the effect of intermittent administration of PTH on osteoblastic differentiation was examined in cultured calvaria cells and then the effect of topical and intermittent administration of PTH was determined by measuring the recovery of alveolar bone loss after inducing experimental periodontitis in rats. Material and Methods: Alkaline phosphatase activity and bone nodule formation were measured in fetal rat calvaria cells. Experimental periodontitis was induced by placing nylon ligature around rat maxillary molars for 20 d. After ligature removal (day 0), PTH was topically injected into buccal gingiva three times a week for 10 wk. Micro‐computed tomography analysis and histological examination were performed on days 35 and 70. Results: Intermittent exposure of PTH in calvaria cells increased alkaline phosphatase activity and bone nodule formation by 1.4‐ and 2.4‐fold, respectively. Ligature procedures induced marked alveolar bone loss around the molars on day 0 and greater bone recovery was observed in the PTH‐treated rats on day 70. An increase in osteoid formation on the surface of alveolar bone was detected in the PTH‐treated rats. Conclusion: Intermittent treatment with PTH stimulated osteoblastic differentiation in fetal rat calvaria cell cultures, and topical and intermittent administration of PTH recovered alveolar bone loss in rat experimental periodontitis.     

PBL教学法在口腔预防教学中的应用

目的 尝试PBL教学法在口腔预防教学中的应用。方法 选择口腔专业二年级学生作为研究对象,其中,一班实施PBL教学,另一班采用传统教学,对两班期末考试成绩进行分析比较。结果 PBL教学班与传统教学班想比,PBL教学班稍高一点,但无统计学差异(P>0.05);综合分析能力有统计学差异(P<0.05)。结论 PBL教学法可以提高学生解决问题及综合分析问题的能力。     

Streaming liver VII: DNA turnover in acinus zone-3

ABSTRACT— Livers of four young, male, random-bred rats weighing 250 g were fixed in formalin and stained with Feulgen. In each section, 50 hepatocytes were randomly selected and their distance from the nearest terminal hepatic vein was measured with an eye-piece micrometer. Distance was expressed in two units: 1. micrometer and, 2. cell location, or the cell number separating a sampled cell from the terminal hepatic rim. The sections were scanned with an image cytometer. The tissue was magnified × 400 and digitized into 512 × 512 pixels. The software determined the nuclear boundary and estimated its area and optical absorbance, which was expressed in relative DNA units. One unit equals the absorbance of a diploid lymphocyte. Nuclear area and optical absorbance measurements were made up to 220 μm distance from the terminal hepatic vein which roughly covers zones 2 and 3. Previously we have shown that in zones 1 and 2 hepatocyte nucleus enlarges and becomes polyploid. The present study demonstrates that in zone-3 this trend is reversed, nuclear area and DNA absorbance decline. The average hepatocyte advances 2 μm daily. In zone-1 it accumulates daily 0.005 DNA absorbance units and in zone-3 it loses daily 0.24 DNA absorbance units. It is proposed that in zone-3 DNA leaves the intact cell in a physiological way. DNA accumulation and polyploidy are regarded here as forms of gene amplification which may be reversed, so that under these circumstances amplified DNA may be “deamplified” and the excess DNA leaves the cell.