Transmission electron microscopy of early microbial colonization of human enamel and root surfaces in vivo

Abstract – This study describes the early microbial colomization of teeth by the use of light-and transmission electron microscopy. Six dental students carried a total of 60 test pieces of unerupted enamel and root surface in intraoral acrylic appliances for 4, 8, 12, 24 and 48 h, during which periods oral hygiene was abandoned. Pronounced variations were recorded in structure and thickness of the pellicle across the individual surfaces of both dental tissues. Bacterial single-cell colonization increased the electron density of the adjoining pellicle. Micro-colonies of bacteria were observed in relation to enamel surface irregularities such as perikymata, while the distribution on root surfaces appeared incidental. Root surfaces were generally colonized by thicker deposits than homologous enamel surfaces although the structural composition of the microbiota was similar. Gram-positive bacteria with thick cell walls appeared in coccoid or rod-shaped configurations depending on the age of the bacterial deposit. These bacteria were further characterized by selective invasion between collagen fibers. After 48 h the complexity of the microbiota was increased by the establishment of new bacterial species in the superficial layer. It is concluded that the pattern and composition of the early microbiota on teeth is more complex and variable than hitherto assumed.     

25例产道血肿及其预后的临床分析

目的：探讨产道血肿形成的病因，临床处理及预后。方法：选取2001年8月至2006年8月阴道分娩的4000例产妇，其中25例发生产道血肿，对其进行回顾性分析，通过分析其病因，临床处理及转归，对该病的预防，诊治经验和教训进行总结评价。结果：产道血肿的发生率为0．625％，经过积极有效的处理，25例发生产道血肿的产妇均痊愈。结论：分娩过程中，应仔细询问产妇病史，对存在有可能发生出血倾向的高危孕妇应严密观察，争取做到早发现；而已发生血肿的产妇，应针对不同病因早治疗，以改善产妇的预后。     

神经根变异与特殊型椎间盘突出症

回顾5例由于神经根变异或特殊类型椎间盘突出引起的腰腿痛病人,对其病理及术中处理做了介绍,认为由于神经根的解剖变异,更容易受到椎间盘突出的卡压。手术中如临床症状符合椎间盘突出症,而预定探查间隙未发现突出物,或与临床症状不符者,应根据神经根激惹及松紧程度,扩大探查范围,查明造成疼痛的原因,避免二次手术。     

Agenesis of permanent incisors in a mediaeval maxilla and mandible: aetiological aspects

A paleopathological maxilla and mandible with tooth agenesis were analyzed, focussing on the aetiology of the condition. The jaw material, derived from an adult mediaeval male, was examined by standard anthropological analyses, including radiography. In the maxilla there was agenesis of three permanent incisors and one premolar, and in the mandible of one permanent incisor and two permanent molars. Absence or marked reduction of the incisive foramen and the nasopalatine canal was found. The pattern of tooth agenesis was similar to the pattern observed in contemporary individuals, except for the agenesis of one permanent maxillary centreal insisor. It is suggested that the pronounced lack of the premaxillary area of the nasopalatine canals and the incisive foramen. As the condition can be ascribed to deviations in the prenatal developments, this investigation shows that embryological developmental patterns, which form the basis for the pattern of tooth agenesis, should be taken into account when evaluation dry bonde patholgy.     

Single visit root canal treatment: incidence of postoperative pain using three different instrumentation techniques

A clinical study was carried out on nonvital maxillary central incisors to evaluate the incidence of postoperative pain following single-visit root canal treatment using three different instrumentation techniques. Ninety teeth from 78 patients whose ages ranged from 14 to 63 years were selected and divided into three groups. Each group (30 teeth) was prepared by a different coronal-to-apical technique using different instrument movement depending upon the technique employed: modified double-flared, crown-downpressureless and balanced force techniques. No difference was observed in the incidence of postoperative pain among the groups.     

家兔肝的神经支配

本实验共用家兔17只,将20%的HRP溶液100μl,经肝门多点注入,其中10只家兔出现标记细胞.两侧T_(2-12)背根节内共270个,左侧占51.11±3.04%,右侧为48.89±3.04%,左、右侧差异无显著性(P>0.05).在T_(5-8)背根节内的标记细胞较多,占总数的59.26±2.99%,中、小型细胞共占94.53±1.60%.两侧结状神经节内的标记细胞共143个.左侧占53.15±4.17%,右侧占46.85±4.17%.两侧差异无显著性.中、小型细胞共占93.01±2.13%.两侧腹腔神经节内的标记细胞较多,计数其中2例,共582个,左侧占59.79±2.03%,右侧为40.21±2.03%.在迷走神经背核内仅发现2个标记细胞.     

The role of ocular torsion in visual measures of vestibular function

This brief review highlights problems in the interpretation of results about perceived postural roll-tilt of human subjects undergoing roll-tilt around their naso-occipital axis, when visual stimuli are used as a means of indicating perception. The otolithic stimulus, which causes the changes in perceived posture, also causes the eyes to roll (or tort). In turn, the altered torsional position of the eye causes the perceived orientation of visual stimuli to change. Consequently, indicators of postural perception, which rely on visual stimuli, are a confounded combination of two factors; the person's perceived postural roll-tilt, and the effect of the otolithic stimulus on ocular torsional position. Consequently, setting of a visual stimulus do not permit direct unambiguous interpretation of a subject's perceived postural roll-tilt.     

The relation between conduction velocity and axonal length

Motor evoked potentials (MEPs) obtained by electrical root stimulation and F waves were used to examine the proximal nerve conduction velocity (CV) to tibialis anterior (TA), extensor digitorum brevis (EDB), flexor carpi radialis (FCR), and abductor pollicis brevis (APB) muscles in 40 humans. By subtracting motor latencies obtained by stimulating the peripheral nerve at the same point from the F-wave and MEP latencies, we could measure the CV over identical proximal segments. It was found that proximal CV to TA and FCR was significantly higher than to EDB and APB, respectively. Combining the data of the proximal CV to all four muscles in relation with axonal length resulted in a highly significant inverse relationship (r² = 0.77). Thus the axonal length explained to a large extent the higher CV of the arm nerves and also the inverse relation between body height and CV. The distal CV was always lower than proximal CV; however, there was no support for an additional effect of this gradient in explaining the relationship between CV and height since it was constant for all body heights. © John Wiley & Sons, Inc.     

部分背根切断对备用背根节NT-3表达的影响

目的　探讨部分去背根后备用背根节 (L6 )各类细胞NT 3及其mRNA的含量变化。　方法　对成年雄性猫行单侧部分背根切断术 (切除一侧L1 ～L5,L7～S2 DRG ,保留L6 为备用根 )。取正常组一侧和术后 3d及 7d组手术侧的L6 DRG制作 2 0 μm厚冰冻切片 ,分别用NT 3抗体及NT 3cRNA探针行免疫组织化学及原位杂交染色。观察NT 3及其mRNA在DRG各类细胞的分布 ,测定NT 3及其mRNA在神经元和卫星细胞的光密度值 ,所得数据用q检验进行统计分析。　结果　部分去背根后 ,各时相备用背根节大神经元内NT 3的光密度值较正常者进行性减少 ,(P <0 0 5 ) ,而NT 3mRNA的光密度值术后 3d减少 ,7d回升至近正常者水平。比较之 ,小神经元和卫星细胞NT 3及其mRNA的光密度值进行性增多 (P <0 0 5 )。　结论　部分背根切断对备用背根节各类细胞NT 3表达的影响不同 ,其功能意义可能与NT 3参与脊髓Ⅱ板层可塑性有关     

家兔内脏大神经传入神经元的节段分布

为探明内脏大神经传入神经元在后根节内的节段分布,本研究将家兔的左侧内脏大神经中枢侧断端浸泡于HRP溶液中。其HRP标记细胞的节段范围为胸_2——胸_(12)节,并以胸_5——胸_(11)节为多。91.2%HRP标记细胞的直径在34微米以下。