OPG mRNA在牙齿萌出过程中(牙合)方组织内的表达

目的:探讨骨保护素(osteoprotegerin OPG)mRNA在牙齿萌出过程中方组织内的表达。方法:运用原位杂交方法检测大鼠下颌第一磨牙方组织内OPG mRNA的表达。结果:大鼠下颌第一磨牙方组织内牙囊成纤维细胞中OPG mRNA在牙齿骨内萌出阶段中期阳性表达,与萌出早、晚期比较差异有统计学意义(P<0.01),其中早期比晚期差异显著(P<0.01);成釉细胞中OPG mRNA在牙齿骨内萌出阶段中期阳性表达,与萌出早、晚期比较差异亦有统计学意义(P<0.01),早期与晚期没有显著性差异(P>0.05)。结论:OPG mRNA在大鼠出生后下颌第一磨牙牙囊成纤维细胞、成釉细胞骨内萌出阶段中期表达最强,牙齿萌出过程中可能通过OPG mRNA表达量的变化来调节牙齿的萌出。     

产前应激子代大鼠海马核转录因子-κB表达的性别差异

本研究采用免疫组织化学和Western blot检测NF-κB p65/p50在产前应激子代海马的表达,并探讨其表达是否存在性别差异。研究结果显示,在雌性子代,中、晚期应激组海马齿状回p65表达显著低于对照组（P〈0．01）,而海马各区p50表达均显著高于对照组（P〈0．01）,中、晚期应激组间p65和p50表达均有显著差异（P〈0．01）。在雄性子代,中、晚期应激组海马齿状回p65表达显著高于对照组（P〈0．01）,晚期应激组海马各区p50表达均显著低于对照组（P〈0．05,P〈0．01）,中、晚期应激组间p65和p50表达均有显著差异（P〈0．01）。雌、雄子代比较,对照组雌、雄p65表达差异极显著妒〈0．01）,p50仅在海马CA1区表达差异极显著（P〈0．01）;中期应激组雌、雄子代大鼠海马p65／p50表达无显著差异;晚期应激组雌、雄海马p65／p50表达均有极显著差异（P〈0．01）。Western blot与免疫组织化学结果基本一致。结果表明,产前不同时期的应激显著影响子代海马NF-κB p65和p50表达,且有性别差异,这可能是产前应激对子代雌、雄大鼠学习记忆能力影响差异的机制之一。     

短期高浓度氟对小鼠磨牙成釉细胞形态及BMP-4表达的影响

目的:研究短期高浓度氟对小鼠磨牙成釉细胞形态及骨形成蛋白-4(BMP-4)表达的影响,探讨氟对牙本质发育的相关机制。方法:选择40只4日龄的ICR小鼠为研究对象,随机分2组各20只,每组对照鼠与实验鼠各半,对实验动物进行单次腹腔注射,剂量分别为10mg/kg和20mg/kg的Na F,对照组动物则进行单次腹腔注射等剂量的Na Cl,24小时后处死动物。采用免疫组化染色观察高浓度氟对小鼠磨牙不同分化阶段成釉细胞形态及BMP-4表达的影响。结果:成釉细胞在分泌过渡期及早、晚期对短期暴露高浓度F-敏感,与对照组小鼠相比,实验组小鼠成熟期成釉细胞无明显变化,过渡期与分泌晚期成釉细胞中BMP-4的表达显著降低,差异有统计学意义(P0.05)。结论:短期高浓度氟对分泌过渡期及晚期成釉细胞中BMP-4的表达有抑制作用。     

检测人老化胎盘组织中miR-182的表达

目的：通过检测miR-182在正常妊娠各期、老化胎盘组织中的表达,探讨miR-182在胎盘发育过程中的调控作用,并同时探讨miR-182与血管内皮生长因子（VEGF）蛋白表达的相关性,为寻找胎盘老化特别是胎盘提前老化发生机制提供依据。方法：采用实时荧光定量PCR方法检测42例标本（早孕绒毛和胎盘组织）中miR-182的表达情况。结果：miR-182在正常妊娠早孕绒毛组织、正常妊娠胎盘组织及老化胎盘组织中均表达。miR-182表达水平各个组间比较：早期与中期妊娠组、中期与晚期未足月妊娠组、晚期未足月与晚期足月妊娠组有显著差异（P〈0.05）;胎盘老化组与正常妊娠早期、中期、晚期未足月、晚期足月组有极显著差异（P〈0.01）;妊娠的早期、中期、晚期,miR-182的表达逐渐增多,老化胎盘组织中miR-182高水平表达。结论：miR-182与胎盘老化的发生高度相关,可能在胎盘老化机制中起重要的调控作用。     

孕酮对新生大鼠低氧缺血性脑损伤中MMP-3表达的影响

目的：研究孕酮（PROG）对新生大鼠低氧缺血后脑内基质金属蛋白酶3（MMP-3）表达的影响。方法：建立新生大鼠低氧缺血性脑损伤动物模型,伊文思兰（EB）染色和电镜观察新生鼠低氧缺血性脑损伤血一脑屏障的通透性改变;免疫印迹（Western blot）方法检测大脑皮层MMP-3表达。结果：电镜显示低氧缺血组血-脑屏障完整性明显破坏：EB染色结果表明低氧缺血组血-脑屏障通透性明显高于假手术组,差异极显著（P〈0．01）,孕酮组血-脑屏障通透性明显低于低氧缺血组,有显著性差异（P〈0．05）;Western blot结果显示低氧缺血组MMP-3蛋白表达显著高于假手术组（P〈0．01）;孕酮组MMP-3蛋白表达显著低于低氧缺血组（P〈0．05）。结论：孕酮通过减少MMP-3的表达,降低血一脑屏障的损伤,这可能是其发挥脑保护作用的机制之一。     

戊四氮致痫大鼠情感反应、学习记忆功能及海马N-甲基-D-门冬氨酸受体mRNA表达的改变

目的：探讨实验性癫痫持续状态（SE）对大鼠认知功能的影响及N-甲基-D-门冬氨酸（NMDA）受体表达的变化。方法：戊四氮诱导大鼠SE,采用抬高迷宫和Morris水迷宫观察大鼠情感反应和学习记忆功能的改变。RT-PCR方法检测大鼠海马NMDA受体亚单位NR1mRNA的表达。结果：sE组大鼠在抬高迷宫开放臂中逃避时间延长（P〈0．01）,进入次数增多（P〈0、01）;水迷宫中逃避潜伏期延长（P〈0.01）,搜寻策略变差（P〈0．05）,平台象限游泳时间百分比降低（P〈0．01）,穿越平台次数减少（P〈0．01）。同时伴有海马NR1mRNA表达下调（P〈0．01）。结论：SE可使大鼠情感行为改变和学习记忆功能受损,NR1可能参与这一变化的病理生理过程。     

PKC、PKA信号通路在调控体外培养人牙囊细胞VEGF表达中的作用

该文主要探讨PKC、PKA信号通路在调控体外培养人牙囊细胞VEGF表达中的作用。选取生长状态良好的第4代人牙囊细胞,采用Real-time PCR和Western blot分别检测PKC激动剂（PMA）、PKC非特异性抑制剂（G 6983）、PKC-α和γ特异性抑制剂（HBDDE）、PKC-β特异性抑制剂（LY333531）、PKA激动剂（dbcAMP）和抑制剂（KT5720）对体外培养人牙囊细胞VEGF mRNA和蛋白表达的影响。结果显示,PMA组和PMA＋HBDDE组VEGF mRNA和蛋白的表达水平明显高于对照组,差异有统计学意义（P〈0.05）;而PMA＋G 6983组和PMA＋LY333531组VEGF mRNA和蛋白的表达水平与对照组之间无明显差异（P〉0.05）。dbcAMP组VEGF mRNA和蛋白的表达水平明显高于对照组,差异有统计学意义（P〈0.05）;而dbcAMP＋KT5720组VEGF mRNA和蛋白的表达水平与对照组之间无明显差异（P〉0.05）。这表明,PKC、PKA信号通路均参与了体外培养人牙囊细胞VEGF表达的调控,其中PKC信号通路中参与调控的亚型是PKC-β。     

慢性低O2高CO2对大鼠海马神经细胞TLR4和NFκB的影响

目的：探讨慢性低O2高CO2对大鼠海马神经细胞TLR4和NFκB的影响及作用。方法：采用慢性低O2高CO2肺动脉高压大鼠模型,30只大鼠随机分为正常对照组（NC）、低O2高CO2 2周组（2HH组）和低O2高CO2 4周组（4HH组）,免疫组织化学法检测海马CA1／3区细胞TLR4和NFκB的表达,TUNEL法检测海马细胞凋亡。结果：模型组大鼠海马CA1／3区TLR4蛋白的表达随着时间延长而显著,2HH组（CA1：0．1275±0．0242,CA3：0．1156±0．0376）,4HH组（CA1：0．1522±0．0187,CA3：0．1427±0．0453）,与NC组比较有显著性差异（P〈0．05,P〈0．01）。NC组大鼠海马CA1／3区可见NFκB／p65少量表达于胞浆,而模型组可见NFκB／p65在细胞核内不同程度表达,2HH组（CA1：0．1326±0．0324,CA3：0．1301±0．0112）,4HH组（CA1：0．1612±0．0428,CA3：0．1578±0．0365）,与NC组比较分别有显著性差异（P〈0．05,P〈0．01）。模型组大鼠海马CA1／3区细胞凋亡明显增多,与NC组比较分别有显著性差异（P〈0．01）,以4HH组为著。结论：TLR4和NFκB激活可能在慢性低O2高CO2大鼠海马神经细胞凋亡中有重要作用。     

吸烟大鼠肺脏AQP4和MUC5AC的表达及其与一氧化氮的关系

目的：研究烟草烟雾吸入对大鼠肺组织水通道蛋白4（AQP4）和粘蛋白5AC（MUC5AC）表达的影响及其与支气管肺泡灌洗液内一氧化氮代谢物水平的关系,探讨氧化应激对肺部水转运和粘液分泌的影响。方法：免疫组化法观察AQP4在肺组织内的表达,平均光密度法比较模型组和空白组大鼠AQP4的表达差异;半定量RT—PCR法检测肺组织内AQP4及MUC5ACmRNA的表达水平;硝酸还原酶法测定各组大鼠支气管肺泡灌洗液内一氧化氮代谢产物的浓度,分析模型组AQP4、MUC5ACmRNA的表达水平与支气管肺泡灌洗液内一氧化氮代谢物浓度之间的相关关系：结果：AQP4在空白对照组呈强阳性染色,在模型组呈弱阳性染色,两者平均光密度值有显著差异（P〈0．05）。模型组动物肺组织AQP4mRNA的表达降低,MUC5ACmRNA的表达升高,与空白组比较均有显著差异（P〈0．05）,模型组动物支气管肺泡灌洗液内一氧化氮代谢产物的浓度与肺组织AQP4mRNA表达水平呈负相关,相关系数r=-0．798,（P〈0．05）,与MUC5ACmRNA的表达水平呈正相关,相关系数r=0．857,（P〈0．05）。结论：吸烟可导致肺组织AQP4表达下降进而影响气道内水的转运。一氧化氮可能参与了烟雾吸入动物模型中AQP4与MUC5AC基因袁达的调控．     

Tooth loss and tooth retention in a multitribal group of Bantu-speaking South African blacks: A study on 500 dry mandibles

Tooth loss and tooth retention in adult South African Bantu-speaking Negroes were studied from data derived from 500 dry mandibles. The tribe, sex, and stated age of the specimens were available. Mandibles were equally distributed over the third to seventh decade of life. The presence of dental units was recorded and analysed within and between decade age groups. The mandibles carried a total of 5,459 dental units. Between the third and fourth decades of life and between the sixth and seventh decades, the reduction of the frequency of dental units was mild and statistically not significant. It was, however, severe and significant between the fourth and fifth, and the fifth and sixth decades. In the third-decade group, most teeth were found in the anterior region with a tendency to diminish in number posteriorly. After the third decade there was a definite persistence of first premolars and canines with significant tendency toward loss of teeth anterior and posterior to them. Only the incisors and third molars showed significant reduction in number from the third to the fourth decade. The reduction of all teeth was statistically significant later, until the sixth decade of life. Although there was loss of teeth from the sixth to the seventh decade, it was not significant for any of the homologous dental units. There is a possibility that some dietary differences existed between the older subjects (50–70 years old) and the younger ones (20–49 years old) which may have had some influence on the results.     

Size and morphology of the permanent dentition in prehistoric Ohio Valley Amerindians.

Metric and morphological characterizations of the permanent teeth from a total of 155 prehistoric Amerindians are presented. The individuals represent samples from three Ohio Valley burial complexes (considered together as the Late Diffuse group): Glacial Kame, Adena and Ohio Hopewell. Metric data include common measures of central tendency and dispersion. From these measures estimates and analyses of the magnitude of sexual dimorphism and relative variability are presented as well as analyses of the patterns of these estimates. Forty morphological characters are also tabulated. The results indicate a number of provisional hypotheses: the generally larger tooth size of the Late Archaic Indian Knoll when compared to the Late Diffuse groups is consistent with the hypothesis of mitigated selective pressures in more technologically advanced groups; although tooth size is smaller in the Late Diffuse groups, dental morphology is as complex, or more so when compared to the Indian Knoll group. Since morphology and size do not covary exactly the biocultural forces resulting in smaller tooth size do not seem to act as strongly on dental morphology; odontological differences within the Late Diffuse arise primarily between the Glacial Kame-Adena and the Ohio Hopewell. These differences correspond to major biocultural changes in this area; although provisional hypotheses concerning odontological variability are erected, hypotheses concerning evolutionary trends must await the discovery of evolving lineages within these groups; similarities are noted among all compared groups including the pattern and magnitude of sexual dimorphism and relative variability. These parameters may be similar for all eastern Amerindians during this period; finally, the morphology of the deciduous dentition, which generally predicts that of the permanent teeth, is found to be less complex than the permanent teeth. This may be the result of a selective disadvantage for the individuals in the deciduous dentition sample which is reflected in the dentition.     

Semaphorin 3A controls timing and patterning of the dental pulp innervation

Timing and patterning of dental pulp innervation are strictly spatio-temporally regulated but it is still not known how they are controlled at molecular level. We analyzed postnatal innervation of the dental pulp in the mandibular first molar of mice deficient for Semaphorin 3A (Sema3A) axon repellant molecule. Immunohistochemical localization of nerve fibers on serial sections covering the whole tooth germs using anti-peripherin antibody revealed that nerve fibers were prematurely present within the preodontoblast layer next to the inner enamel epithelium already at PN0 in Sema3A^−/− mice. In contrast, in the wild-type (Sema3A^+/+) mice nerve fibers were seen in the pulp only after enamel formation at PN3. The nerves in Sema3A^−/− pulp were notably defasciculated and thinner compared to that of Sema3A^+/+ mice. A premature formation of an abnormal, enlarged nerve plexus with a high number of arborizations was apparent in the pulp–dentin border target area in Sema3A^−/− already at PN2 whereas in the wild-type mice the first sign of plexus formation was seen at PN7. The expression of mRNAs for Ngf, Gdnf and Ncam neuroregulatory molecules in mandibular molar as well as receptors for neurotrophic factors and class 3 semaphorins including Sema3A (TrkA, p75, TrkB, TrkC, Ret, Npn1, Npn2, PlxA4) in trigeminal ganglia were not altered in the Sema3A^−/− mice. Collectively, this data show that Sema3A serves an essential role in molar tooth pulp innervation controlling the timing of nerve fiber penetration into the pulp, their patterning and the formation of nerve plexus at pulp–dentin border area, and provide further support for the hypothesis that tooth innervation is regulated by the coordinated activity of locally expressed neuroregulatory molecules exerting positive and negative influences on growing dental nerve fibers.     

Congenital defects of the upper lateral incisors (ULI) and the morphology of other teeth in man

A sample of 192 male propositi with at least one ULI either missing or reduced has been compared with 197 male controls in terms of the morphology of the other teeth. Every class of propositi exhibits modifications in the following characters: Significant differences between propositi and controls were found for molar cusp number and groove pattern, particularly in the lower first molar and in propositi with reduced ULI. Significant differences between propositi and controls were also found with respect to caniniform pattern of the lower first premolar. The Carabelli's cusp is rarer in propositi. A hypothesis to account for these observations is proposed.     

Patterning the size and number of tooth and its cusps

Mice and rats, two species of rodents, show some dental similarities such as tooth number and cusp number, and differences such as tooth size and cusp size. In this study, the tooth size, tooth number, cusp size and cusp number, which are four major factors of the tooth patterning, were investigated by the heterospecific recombinations of tissues from the molar tooth germs of mice and rats. Our results suggest that the dental epithelium and mesenchyme determine the cusp size and tooth size respectively and the cusp number is co-regulated by the tooth size and cusp size. It is also suggested that the mesenchymal cell number regulates not the tooth size but the tooth number. The relationships among these factors in tooth patterning including micropatterning (cusp size and cusp number) and macropatterning (tooth size and tooth number) were analyzed in a reaction diffusion mechanism. Key molecules determining the patterning of teeth remains to be elucidated for controlling the tooth size and cusp size of bioengineered tooth.     

Artificial grooves on the Krapina Neanderthal teeth

Gross and microscopic examination of the Krapina Neanderthal dental remains reveals the presence of artificial grooves along the cemento-enamel junction of 14 teeth representing ten different individuals. The grooves display distinct morphological features including their consistent location (primarily on the mesial and/or distal root walls), their troughlike appearance, striations and/or polishing in the channel, and the ridges of reactive cementum bordering the groove. These grooves occur only on erupted, permanent teeth, and except for a single occurrence on a lower I2, all are located on mandibular or maxillary P4-M3. The morphological nature of the grooves is distinct and has been used to distinguish these grooves from root caries and other pathological or natural causes. Based on the close resemblance between artificial grooves at Krapina and those which have been attributed to toothpick use in other fossil and recent populations, we argue the Krapina Neanderthals were habitually probing the interproximal dental spaces with tools.     

Form and patterning of anterior tooth wear among aboriginal human groups

Form and severity of dental attrition was assessed in aboriginal human groups including hunter-gatherers (Eskimos, Australians) and those with dependence to a varying degree on food production (Southwest U.S. and Ohio American Indians). Wear on anterior teeth was both relatively and absolutely greater in the hunter-gatherers, as indicated by comparisons of wear on anterior and posterior teeth which come into occlusion at roughly the same time. Distinct differences in form of anterior wear were also apparent: The hunter-gatherers exhibited steadily increasing incidences of labially rounded wear with greater functional age, while the food-producing groups showed little or no rounding but instead high frequencies of heavily cupped wear (especially in those with premature loss of posterior teeth). These differences were attributed to nonmasticatory utilization of the front teeth in hunter-gatherers and to employment of the anterior teeth in masticatory (grinding) activities necessitated by large-scale molar loss in food producers.     

鲤鱼墩遗址出土人牙的牙齿磨耗和龋齿

距今约6000年以前, 华南先民以渔猎采集经济为主, 并辅之以块茎植物种植的观点已为学界所共识。这种类型的生业方式与长江中下游、华北及其以北地区有着较大的区别。这不仅反映在遗址出土的动植物遗存和生产工具的不同, 也体现在出土人骨体质特征的差异上。后者已初步为C、N稳定同位素的比较研究所证实。本文则利用鲤鱼墩遗址出土的人牙,从牙齿磨耗和龋齿两方面考察上述差异。