A nonrandom interneuronal pattern in the developing frog spinal cord

In the developing spinal cord of the frog, Xenopus laevis, a population of interneurons assumes a pattern that represents a previously undescribed level of organization. Glyoxylic acid treatment and immunocytochemistry show that the neurons contain catecholamines and their synthetic enzyme, tyrosine hydroxylase. Cells are located within the ependymal layer of the floor plate region of the larval spinal cord. The cells have several processes including a long one that projects toward the brain without fasciculating with other labeled processes. In addition, the cytoplasm of the catecholaminergic cells extends into the central canal, showing that they are a population of cerebrospinal fluid-contacting neurons. The spatial domain of catecholaminergic neurons starts abruptly at the boundary between the hindbrain and spinal cord and continues to the tip of the tail. The neurons occupy two longitudinal columns within the sheet of floor plate cells, which includes cells that do not exhibit the catecholaminergic phenotype. Unlabeled cells are intercalated between catecholaminergic cells in each column, giving the labeled cells the appearance of being spaced along the length of the spinal cord. This general arrangement is evident at the time of hatching. Spatial analysis showed that the position of cells along a column is not random. The nonrandom behavior is due to cells being excluded from the area immediately surrounding other catecholaminergic cells. Further analysis showed that the cellular pattern lacks segmental or other periodic repeats. Ultimately, the location of a cell within a column depends upon the position of its closest catecholaminergic neighbor. © 1993 Wiley-Liss, Inc.     

改良尿道板重建卷管尿道成形术与尿道板纵切卷管尿道成形术治疗儿童尿道下裂的疗效对比

目的 比较改良尿道板重建卷管尿道成形术（又称Koyanagi术）与尿道板纵切卷管尿道成形术（TIP）在儿童尿道下裂中的临床疗效。方法 回顾性分析2018年1月—2021年10月甘肃省妇幼保健院收治的104例尿道下裂患儿的临床资料,其中53例患儿行改良Koyanagi术（研究组）,51例患儿行TIP（对照组）。两组患儿术后均随访12个月。比较两组手术时间、术中出血量、术后疼痛及排尿功能、手术成功情况,对比两组术后并发症发生情况。结果 两组手术时间、术中出血量比较,差异均无统计学意义（P >0.05）。两组患儿术后4、12、24和48 h的FLACC评分比较,采用重复测量设计的方差分析,结果 ①不同时间点FLACC评分差异有统计学意义（F =10.871,P =0.000）;②研究组与对照组FLACC评分差异无统计学意义（F =1.849,P =0.157）;③研究组与对照组FLACC评分变化趋势差异无统计学意义（F =2.516,P =0.085）。两组患儿术后12个月的最大尿流率、平均尿流率、排尿量、尿流时间、手术成功率比较,差异均无统计学意义（P >0.05）。研究组术后总并发症发生率低于对照组（P <0.05）。结论 改良Koyanagi术与TIP治疗儿童尿道下裂疗效相近,均可获得满意效果,但改良Koyanagi术在降低术后并发症方面具有优势。     

Stereological study of the developing distal femoral growth plate

The distal femoral growth plate has a uniquely convoluted structure comprised of four mammillate processes. Factors contributing to the development of these processes and overall plate geometry were explored using three-dimensional image analysis of the canine distal femoral epiphysis. The growth plate at birth remains relatively flat until ossification of the epiphysis begins at 1 week of age. Epiphyseal ossification proceeds eccentrically, projecting in the medial-lateral and anterior-posterior directions. Growth plate activity indexed by [3H]thymidine labeling and plate thickness revealed regional differences in cell proliferation. This was measured as a decreased labeling index and thinning of the growth plate in areas capped by the ossifying epiphysis. The eccentric ossification pattern and associated variations in growth plate activity result in definition of an "intraphyseal" groove and medial-lateral oriented sulcus. The groove and sulcus bisect the plate into four quadrants, giving rise to a convoluted structure composed of four areas of plate elevations termed mammillary processes (MP). By 5 weeks, the pattern of ossification results in greater development of the MP in the anterior-medial quadrant and in decreasing order, in the posterior-medial, anterior, and posterior-lateral quadrants. By 10 weeks, a uniform rate of cell proliferation was observed coincident with completion of ossification of the epiphysis. The data suggest that localized variations in growth plate proliferation are associated with ossification of the epiphysis.(ABSTRACT TRUNCATED AT 250 WORDS)     

AO肩锁钢板钩治疗重型肩锁关节脱位

目的评估AO肩锁钢板钩治疗重型肩锁关节脱位的手术疗效.方法回顾性分析两年来27例手术病人的手术治疗和疗效.结果手术方法符合生理结构,手术时间平均30分钟,内固定牢靠.根据Murley和Constant[1]评分,优良率94%.结论 AO肩锁钢板钩治疗重型肩锁关节脱位,手术方法简单,疗效可靠,允许病人术后早期功能锻炼.     

单钉——沟槽柱翼钢板的生物力学实验研究

作者自行研究设计的单钉－沟槽柱翼钢板复位固定治疗腰椎滑脱症。预先采用６具成人尸体的Ｌ３－Ｓ３骨骼做成椎弓崩裂并滑脱模型，采用临床Ｉ型手术方法进行了复位固定，在每片钢板上粘贴６片电阻应变片，进行中心和偏心加载试验，同时进行了弯矩和扭矩试验，在５８６微机上进行了线性回归分析，求出了线性方程及线性相关系数ｒ，中心和偏心加载达到９００Ｎ未出现钢板松动，扭矩和弯矩在８３３Ｎ；ｃｍ和６６６．４Ｎ．ｃｍ以内左右     

System for inducible expression of cre-recombinase from the Foxa2 locus in endoderm, notochord, and floor plate.

We targeted the reverse tetracycline controlled transactivator (rtTA) to the Foxa2 locus (Foxa2(ITA)) to generate a system for regulating Cre-recombinase activity within Foxa2 expression domains, including the endoderm, notochord, and floor plate of early mouse embryos. The use of an internal ribosomal entry site to obtain rtTA expression preserves Foxa2 function of the targeted allele. Cre activity with this system reflects the level of endogenous Foxa2 activity and is also tightly controlled by doxycycline. The location of Cre activity within the broader Foxa2 expression domain can be restricted by altering the timing of doxycycline administration. Isolated floor plate expression can be obtained in this manner. This system will provide a useful tool for manipulating gene expression in endoderm, notochord, and floor plate, all of which are tissues with important structural and patterning functions during embryogenesis.     

Fluid Flow through Filtering Appendages of Insects

Many organisms use structures composed of arrays of cylindersto capture particulate food or molecules form the water or airaround them. The performance of such filters depends on thevelocity of fluid movement through them; hence, mathematicalmodels of flow through fibrous structures can provide insightsabout the functional morphology of biological filters. In thispaper, the authors address the case of feather-like biologicalfilters of finite width and assess several possible models forfluid motion through them by comparing model predictions withobservational data. Two examples of insect appendages are considered:the cephalic fans of black fly aquatic larvae that capture particulatefood and the antennae of adult male moths that catch sex-attractantmolecules released by female moths. The results suggest thatflow through such structures can be much slower than ambientcurrents, that the finest hairs in the structure are the morphologicalfeatures with the greatest effect on leakiness, and that thevelocity of movement (or of ambient flow), as well as the morphologyof such filters, can be critical in determining their performance.     

骨骺牵张与骨骺板的生物力学性质

本研究是对新西兰幼兔股骨远端骨骺进行体内和体外牵张实验.16只兔右股骨经5～10N力每3天一次牵张.4周后的股骨长度值明显大于左侧和0N组.形态学变化是受牵张的骺板增厚,软骨细胞增殖且无骨骺分离骨折.体外骺板抗断裂测试显示夸张后的骺板强度不低于未经牵张的对照侧.8只动物16根股骨于体外接受20～100N力的牵张,其骺板的塑性变形度随牵张力值的增高而增大,抗断裂强度亦不低于未经牵张的骨骺.这些结果表明适量的牵张力和/或低牵张速率是实现“软骨分离”或骨延长的关键.     

人工肱骨头置换与肱骨近端锁定钢板治疗老年复杂肱骨近端骨折的近期临床疗效分析

[摘要] 目的 对比分析人工肱骨头置换术和肱骨近端锁定钢板治疗老年复杂肱骨近端骨折的近期疗效。方法 回顾性分析本院骨科2012年1月~2014年6月采用人工肱骨头置换术和肱骨近端锁定钢板治疗的老年（年龄>65岁）NeerⅢ、Ⅳ部分肱骨近端骨折患者54例，人工肱骨头置换治疗（置换组）30例，肱骨近端锁定钢板内固定治疗（内固定组）24例。比较分析两组手术时间、术中出血量、随访Neer评分及Constant-Murley评分来评定两组临床疗效。结果 两组随访时间相仿，平均随访时间为19.5个月（12~36个月）。内固定组手术时间（101±13）分钟，术中出血量（237.9±32.4）mL，Neer评分（82.5±3.2），Constant-Murley评分（71.7±5.0）；置换组手术时间（98±11）分钟，术中出血量（246.0±39.8）mL，Neer评分（82.9±4.5），Constant-Murley评分（73.5±5.0）。两组手术时间、术中出血量、随访Neer及Constant-Murley评分比较差异均无统计学意义（P＞0.05）。内固定组有1例出现肩关节半脱位，肱骨头置换组有2例出现肩关节半脱位，通过三角巾悬吊后关节脱位均得到纠正。有1例四部分骨折患者，行内固定术后出现内固定松动、肱骨头坏死，改行人工肱骨头置换术。结论 人工肱骨头置换术和肱骨近端锁定钢板治疗老年肱骨近端复杂骨折的近期临床疗效相似，对不可修复的肱骨近端骨折宜行肱骨头置换术。     

股骨粗隆间骨折采用改良L形钢板内固定的生物力学原理与临床应用

作者自1994年始采用自行设计L形钢板内固定治疗不稳定股骨粗隆间骨折60例，平均随访25个月，X线片显示骨折愈合时间6～13周，平均8．9周，伤肢功能在3个月内基本恢复正常，无骨折延迟愈合及髋内翻现象。为论证改良L形钢板的优点，本文采用8具新鲜尸股骨沿着它的外侧、内侧骨皮质粘贴6个应变片，观察股骨近端应变和位移分布，以检验改良L形钢板固定粗隆间骨折的效果。在实验前后将股骨粗隆造成二部分或四部分骨折。利用实验结果给制成应变和位移图，并与鹅头打固定组相比较。在载荷加至1800N时比较两种内固定器械的生物力学性能。结果表明，在治疗不稳定粗隆间骨折中，L形钢板比鹅头钉更具有生物力学的优势。