Healing of Mandibular Body Osteotomies after Plate and Intramedullary Pin Fixation

Osteotomies were created in the left body of the mandible of nine dogs and immediately stabilized with either a six hole dynamic compression bone plate or an intramedullary pin. Cortical bone healing and vascular supply were evaluated at weeks 2, 5, and 10 by microradiography, microangiography, and correlated histology of selected mandibular slices. Perforating arterioles from the buccal mucosa maintained vascular supply to rostral mandibular segments. The mandibular body rostral to the osteotomy site and caudal to the canine tooth suffered an interruption of vascular supply that was replaced by a temporary extraosseous supply during healing of the osteotomy. Intramedullary pin placement resulted in destruction of rostral teeth. There was an inflammatory response around the rostral portion of all intramedullary pins. Osteotomy sites involving tooth roots resulted in no disruption of the normal vascular or neural structures of the tooth pulp.     

Effects of Three Intramedullary Pinning Techniques on Proximal Pin Location and Articular Damage in the Canine Tibia

The effects of three different techniques of intramedullary (IM) pin placement on pin location and incidence of stifle joint injury were evaluated using 70 cadaver canine tibiae after middisphyseal osteotomy. In 50 tibiae, pins were placed retrograde in either a nondirected (group A) or a craniomedially directed fashion (group B) with 25 tibiae in each group. Pins were driven normograde (group N) in 20 tibiae. All the stifles were dissected to qualitatively evaluate pin interference with different joint structures. End-on radiographs of the tibial plateaus were used to quantitatively evaluate pin location. Interference with the caudal cruciate ligament, medial meniscus, lateral meniscus, or meniscal ligaments was not observed in any group. There was a significant association between pinning technique and incidence of involvement of the cranial cruciate ligament ( P < .005), patella ( P < .001), patellar ligament ( P < .005), and femoral condyle ( P < .01). Pin location for group A was significantly different from either other group in a cranial-caudal direction ( P = .003), and was significantly different from group N in a medial-lateral direction ( P = .005). No significant difference was observed between pin location for groups B and N in either plane. It was concluded that although nondirected retrograde pinning cannot be recommended, retrograde pins directed craniomedially may be an acceptable technique for the repair of proximal to mid-diaphyseal tibial fractures if care is taken to properly seat the pins.     

Mechanical Evaluation of Half-Pin (Type 1) External Skeletal Fixation in Combination with a Single Intramedullary Pin

Half-pin (type 1) external skeletal fixators with four, three, and two fixation pins and an intramedullary pin, and four-pin external skeletal fixators without an intramedullary pin were applied to prepared canine femurs. Load to failure, load to yield, safe load, and stiffness under compressive and torsional loads were calculated. When tested in compression, all measurements for the four-pin fixators with an intramedullary pin were significantly higher than for the two-pin fixators with an intramedullary pin. The values for all parameters except load to yield were significantly higher for the four-pin fixators with an intramedullary pin than for the four-pin fixators without an intramedullary pin. When tested in torsion, all measurements for the four-pin fixators with an intramedullary pin were significantly higher than for the two or three-pin fixators with an intramedullary pin.     

一株放线菌对丝素纤维的降解作用

探讨了一株从土壤中分离到的放线菌(C3菌株)对丝素纤维的降解特性。结果表明,C3菌株在28～37℃范围内对蚕丝纤维均具有较强的降解活性;培养基中的碳源能抑制C3菌株的降解活性,而氮源基本无影响,即在缺乏碳源和氮源或单独缺乏碳源的培养基中降解活性增强。在以丝素粉作为唯一碳源和氮源的色氨酸培养基中,C3菌株在28℃下培养6 d左右降解速度最大,并延续至第12天左右。电镜观察表明,培养基中接种C3菌株14 d时,菌丝体已经大量繁殖,丝素纤维出现降解凹陷,部分丝素纤维出现断裂;培养42 d时,丝素纤维已完全降解。     

Holding Power of Different Pin Designs and Pin Insertion Methods in Avian Cortical Bone

Objective —To measure pullout strength of four pin types in avian humeri and tibiotarsi bones and to compare slow-speed power and hand insertion methods.
Study Design —Axial pin extraction was measured in vitro in avian bones.
Animal Population —Four cadaver red-tailed hawks and 12 live red-tailed hawks.
Methods —The pullout strength of four fixator pin designs was measured: smooth, negative profile threaded pins engaging one or two cortices and positive profile threaded pins. Part 1: Pins were placed in humeri and tibiotarsi after soft tissue removal. Part 2: Pins were placed in tibiotarsi in anesthetized hawks using slow-speed power or hand insertion.
Results —All threaded pins, regardless of pin design, had greater pullout strength than smooth pins in all parts of the study ( P < .0001). The cortices of tibiotarsi were thicker than the cortices of humeri ( P < .0001). There were few differences in pin pullout strengths between threaded pin types within or between bone groups. There were no differences between the pullout strength of pins placed by slow-speed power or by hand.
Conclusions —There is little advantage of one threaded pin type over another in avian humeri and tibiotarsi using currently available pin designs. There were few differences in pin pullout strengths between humeri and tibiotarsi bones. It is possible that the ease of hand insertion in thin cortices minimizes the potential for wobbling and therefore minimizes the difference between slow-speed drill and hand insertion methods.
Clinical Relevance —Threaded pins have superior bone holding strength in avian cortices and may be beneficial for use with external fixation devices in birds.     

Comparison of a New Braid Fixation System to an Interlocking Intramedullary Nail for Tibial Osteotomy Repair in an Ovine Model

Objectives— To compare bone healing of tibial osteotomy repaired with Nitinol wire braid and hardened steel rods (Braid system) and polymethylmethacrylate bone cement with an interlocking intramedullary (IM) nail fixation in an ovine model.
Study Design— In vitro and in vivo experimental study.
Animals— Adult female sheep (n=22).
Methods— Using sheep tibia, a middiaphyseal transverse osteotomy was performed in the right tibia, which were then randomly assigned to the Braid system group or IM nail group (n=5). The left tibia were used as controls. The torsional properties of tibial constructs were compared. The study was repeated in vivo in 12 sheep and mechanical properties and bone healing were evaluated at 12 weeks.
Results— In vitro, there was no significant difference in torsional stiffness between the groups. In vivo, operative time for the Braid system group was significantly shorter than the IM nail group. At 12 weeks, there were no significant differences in maximum torque and torsional stiffness between IM nail and Braid system groups nor were there significant radiographic or histologic differences between the groups.
Conclusions— The Braid system might decrease operative time for repair of transverse middiaphyseal tibial fractures and result in similar bone healing at 12 weeks after surgery compared with an interlocking IM nail repair.
Clinical Relevance— A Nitinol Braid system may be a treatment option for transverse midshaft tibial fractures.     

Addition of Glutathione to an Extender for Frozen Equine Semen

The manipulation of equine semen during cryopreservation reduces sperm viability and fertility because of, among other factors, membrane lipid peroxidation that makes cells highly susceptible to free radicals and reactive oxygen species (ROS). The oxidative effect caused by the generation of ROS can be reduced by the addition of antioxidants to the seminal plasma or to the extenders used for freezing. The current study was performed to test the in vitro effect of exogenous glutathione added in five different concentrations (control, 2.5 mM, 5.0 mM, 7.5 mM, and 10 mM [treatments 1-5, respectively]) to the extender for 12 stallions. Analyzed parameters were sperm motility, viability, and acrosome and plasmatic membrane integrity. Total motility was higher in treatments 1 and 2 (P < .05); viability, progressive motility, and plasmatic membrane integrity were higher in treatment 2 (P < .001). As for acrosome membrane integrity, treatment 3 showed the best results (P < .05). The addition of 2.5 mM glutathione to the freezing extender preserves total motility and increases sperm viability, progressive motility, and plasmatic membrane integrity. Concentrations above 2.5 mM were deleterious to spermatozoa.     

益生菌是否能减少家禽跛足的发生

跛足是现代家禽养殖生产中日益严重的问题,并且是造成肉鸡死亡的重要原因之一。它会影响家禽的活动性,且通常会引起疼痛。跛足会导致家禽患病,并限制其自然活动,很可能会造成采食量和饮水量的下降。     

微量矿物质元素提高反刍动物纤维物质利用率的研究进展

从微量矿物质元素铜(Cu)、钴(Co)、铁(Fe)、锌(Zn)、锰(Mn)、硒(Se)、碘(Ⅰ)在反刍动物体内的生理功能、对反刍动物瘤胃微生物产生的作用,以及微量矿物质元素对纤维物质利用率的影响等方面对各矿物质元素功能作了进一步阐述。说明了补添矿物质对提高反刍动物纤维物质利用率的重要作用。     

星状病毒鸽群分离株的全基因分析

为分析鸽星状病毒中国分离株的特性,采用高通量测序方法,测定从山东省青岛市某活禽市场分离的鸽星状病毒基因组,并对其进行特性分析与比较基因组研究。结果显示:该病毒全基因大小为6 872 bp,具有与其他星状病毒相似的结构和基因顺序;5'端有一段非编码区,3'端为聚A尾。与15株代表性毒株的全基因组和衣壳蛋白氨基酸序列同源性分析证实,该病毒与挪威2003年分离的鸽星状病毒同源性高,属于GroupⅠ基因群禽星状病毒,而与我国2011年报道的鸽星状病毒存在差异。分析结果表明,我国鸽群中的星状病毒较为多样。     

氮添加对青藏高原高寒草甸土壤磷组分的影响

磷是一种影响草地植物生产力和生态系统功能的重要养分。本文研究了3个氮添加水平下(5，10和15 g ·m^-2)青藏高原海北高寒草甸(海拔3 100 m)土壤磷组分的变化特征及其主要影响因素。研究表明：N5处理下土壤磷的生物有效性增加。N5处理显著提高了活性磷库的含量，其中NaHCO₃-Pi的含量和比例均显著增加。N15处理下植物生物量和地上部含磷量增加，土壤活性磷含量无显著变化，N15处理下仅土壤残余态磷(Residual-P)显著下降。氮添加下影响土壤磷组分变化的关键因素包括土壤pH值、微生物生物量碳(Microbial biomass carbon,MBC)和微生物生物量氮(Microbial biomass nitrogen,MBN)。在高寒草甸氮添加能够通过降低土壤pH值和增加微生物生物量来提高土壤磷的有效性。     

一株具有产酸能力的芽孢杆菌的筛选及性能检测

 为了分离具有产酸能力的芽孢杆菌,使用菌种分离培养基从牛粪中分离得到一株具有产酸能力的芽孢菌,命名为GF1。根据该菌株的生理生化特性鉴定和16S rDNA序列测定分析, 初步鉴定该菌为蜡样芽孢杆菌。对GF1发酵液中的代谢产物进行液相色谱分析,发现GF1可代谢产生乳酸、乙酸等有机酸。对GF1进行液体发酵,通过在沸水中加热10 min灭活菌体,检测GF1最终芽孢率可达到90%以上,对GF1进行耐热、耐酸和耐胆盐处理,发现GF1具有良好的耐热性能和较强的耐酸耐胆盐特性,以小鼠做安全性试验,结果成活率为100 %,表明GF1安全无毒。GF1不仅能够产酸,还可以产生芽孢,可以突破乳酸菌在颗粒料中添加的瓶颈。