Computed tomography of proximal metatarsal and concurrent third tarsal bone fractures in a Thoroughbred racehorse

A 2‐year‐old Thoroughbred filly presented to the William R. Pritchard Veterinary Medical Teaching Hospital at the University of California at Davis for whole body nuclear scintigraphic evaluation after an acute onset of nonweightbearing right hindlimb lameness post race. The use of computed tomography (CT) enabled visualisation of additional pathology that was not initially appreciable using combined imaging modalities of nuclear scintigraphy and digital radiography, which ultimately altered the selected course of treatment. Computed tomography in horses with fractures of the cuboidal bones of the hock can provide valuable additional information regarding fracture configuration and radiographically occult pathology, which may help to guide clinical decisions about treatment.     

大岩桐高频再生体系建立的两种途径

采用大岩桐(Sinningia speciosa) 的叶片、叶柄和根外植体, 经过两种途径建立大岩桐的高效离体再生体系。第1种途径是: 外植体先形成愈伤组织, 愈伤组织分化出不定芽, 再生成不定根, 进而形成再生苗; 第2种途径是: 外植体先形成少量愈伤组织和根, 再产生不定芽, 进而形成再生苗。第1种途径所采用的培养基MS +BA 2.0 mg·L - 1 +NAA 0.2 mg·L - 1 +蔗糖30 g·L - 1 , 芽诱导率达到99.04% , 根诱导率达到98.81% , 每块外植体分化的不定芽数达5.53个; 第2种途径中以MS +NAA 1.0 mg·L - 1 +蔗糖30 g·L - 1为最佳培养基, 芽诱导率达到90.38% , 根诱导率达到100% , 每块外植体分化的不定芽数达2.44个。在3种外植体中以叶片的再生频率最高。经过连续的组织培养, 在大岩桐的再生苗中得到了一些表型变异植株, 包括叶片形态的改变, 植株叶序的改变以及花的改变。其中以叶序和花的改变最有价值,可以为叶序调控机理和成花及花变异机理研究提供良好材料。     

杂交稻自生苗中类似杂草稻的生物学特性

在自然条件下,种植不同时间籼型杂交稻后改种常规粳稻,对粳稻田中的杂交稻自生苗展开调查,分析杂交稻自生苗中出现类似杂草稻的频率及其生物学性状,测定杂交稻自生苗对粳稻产量的影响.结果表明,在粳稻田中籼型杂交稻自生苗可以转变成类似杂草稻,即存在籼粳亚种间异交产生杂草稻的可能;连续种植杂交稻3年后改种常规粳稻田块的杂交稻自生苗密度最高,对常规粳稻产量的影响最大.     

急性心肌缺血大鼠左心室流出道自发性慢反应电位去极离子流变化分析

目的探讨急性心肌缺血大鼠左室流出道自发性慢反应电位去极离子流的变化。方法常规玻璃微电极细胞内方法观测急性心肌缺血大鼠的离体心脏最大舒张电位(MDP)、0相除极幅度(APA)、0相最大除极速度(Vmax)、4相自动除极速度(VDD)、复极50%(APD50)和90%(APD90)的时间以及自发放电频率(RPF)。结果与给药前相比①1.2mmol.L-1河豚毒(TTX)使APA和Vmax有所减小(P<0.05),VDD和RPF明显减慢(P<0.01);②1.0μmol.L-1维拉帕米(VER)可使该慢电位的APA、Vmax、VDD明显减小,RPF减慢(P<0.01);APD、APD90延长(P<0.05);③2mmol.L-1 4-氨基吡啶(4-AP)使该慢电位的MDP的绝对值、APA、Vmax减小,VDD和RPF加快(P<0.01);④1.5mmol.L-1 CsCl作用6min时,VDD和RPF明显降低(P<0.05),10min时恢复。结论①左心室流出道的自发慢电位0相主要去极离子流除Ca2+内流外,还有少量Na+内流。②4相去极离子流中,除Ca2+、Na+的内流和Ik衰减外,If电流可能也起部分作用。     

环吡酮胺纳米乳的制备及含量测定

【目的】对环吡酮胺纳米乳的配方及制备方法进行研究,并对其理化性质、稳定性、含量进行考察。【方法】利用伪三元相图优选配方,制备环吡酮胺纳米乳,通过透射电子显微镜、激光粒度测定仪、UV分光光度计对其形态、粒径和含量进行考察,通过高速离心试验和留样观察试验对其稳定性进行考察。【结果】以乙酸异丙酯为油相,聚氧乙烯氢化蓖麻油为表面活性剂,乙醇为助表面活性剂,在表面活性剂与助表面活性剂的质量比Km=3∶2时,室温下可形成稳定的水包油型纳米乳体系;乳滴呈球形,分布均匀,平均粒径为11.4nm,多分散系数(PDI)为0.132。稳定性试验显示,环吡酮胺纳米乳经10 000r/min离心20min及在-4,25,60℃贮藏6个月后,纳米乳液仍澄清均一,未出现分层、破乳现象。含量测定显示,在306.2nm处测定纳米乳液中环吡酮胺含量的专属性良好。【结论】获得制备环吡酮胺纳米乳的配方,且该配方制备工艺简单可行,制得的环吡酮胺纳米乳稳定性高。     

Highly metastatic ovarian yolk sac carcinoma in a rat

We investigated a highly metastatic ovarian yolk sac carcinoma in a 52-week-old female Crl:CD(SD) rat. Macroscopically, the present case had severe ascites, bilateral ovarian masses and numerous nodules in the abdominal and thoracic cavities. Histopathologically, these masses and nodules were generally composed of two types of cells mimicking a parietal and visceral yolk sac. The parietal cells were round to polygonal, contained eosinophilic droplets and were arranged in nests and cords in the eosinophilic matrix. Both the intracytoplasmic droplets and the matrix were stained positively with PAS. The visceral cells were cylindriform, and proliferated in papillary and tubular patterns and occasionally formed Shiller-Duval body-like structures. In the dissemination sites, the neoplastic cells proliferated on the surface of the various tissues and often infiltrated into deeper parts of the tissues. Immunohistochemically, both neoplastic cells were positive for α-fetoprotein and keratin, and the eosinophilic matrix was positive for laminin. Ultrastructurally, the parietal cells had dilated rough endoplasmic reticulums, which were filled with electron-lucent laminated structures. The visceral cells had poorly to moderately developed intracytoplasmic organelles and were interconnected with desmosomes. Taken together, the present tumor was diagnosed as yolk sac carcinoma arising from the ovary and was characterized by not only high metastasis but also invasive infiltration with biphasic proliferation of the parietal and visceral cells.     

Patterns of scintigraphic uptake in the fetlock joint of Thoroughbred racehorses and the effect of increased radiopharmaceutical uptake in the distal metacarpal/tarsal condyle on performance

Reasons for performing study: The effect of palmar osteochondral disease lesions on performance of Thoroughbred (TB) racehorses is unclear. There is a need to describe patterns of radiopharmaceutical uptake (IRU) in fetlock joints of TB racehorses and to evaluate post scintigraphy performance. Hypotheses: IRU in the metacarpal (MC) and metatarsal (MT) condyles is more common than IRU in the parasagittal grooves and is associated with poorer post diagnosis performance than controls. Methods: Location of IRU within the fetlock region was identified and graded subjectively in TB racehorses. Performance variables were determined from race records for horses with moderate/marked MC/MT condylar IRU (cases), other horses undergoing scintigraphy (scintigraphy controls) and age/sex matched controls from the last race in which a case participated (controls). Statistical analyses included quantile regression, Fisher's exact test, Kaplan‐Meier survival curves, log‐rank test and Cox regression. Results: Metacarpal/MT condylar IRU was identified in 103/220 horses with only 3/220 having parasagittal IRU. Moderate/marked IRU was identified in the MC and MT condylar regions in 62 and 39 horses, respectively, with palmaromedial and plantarolateral IRU most common. Fore‐ and hindlimb cases had fewer starts, reduced earnings (P<0.001) and reduced earnings/start than controls respectively. Cases were more likely to return to racing later than controls following a rest period. Cases were older than scintigraphy controls. Conclusions: In TB racehorses presenting for lameness MC/MT condylar IRU is the most common abnormality identified within the fetlock joint. Racehorses with moderate/marked condylar IRU have a shortened racing career, are less successful than age/sex matched controls and are older than other racehorses presented for scintigraphy. Potential relevance: Overload of the MC/MT condyles is a common and significant problem in TB racehorses that is readily identified with scintigraphy. Scintigraphy of horses that are lame or performing poorly is less useful for screening for potential condylar fractures.     

The use of small (2.7 mm) screws for arthroscopically guided repair of carpal chip fractures

Reasons for performing the study: Removal of large chip fractures of the carpal bones and the osteochondral deficits that result, have been associated with a worse prognosis than removal of small fragments in similar locations. Hypothesis: Reducing the articular defects by repair of large osteochondral fragments may have advantages over removal. Methods: Horses with osteochondral chip fractures that were of sufficient size and infrastructure to be repaired with small (2.7 mm diameter) AO/ASIF cortex screws were identified and repair effected by arthroscopically guided internal fixation. Results: Thirty‐three horses underwent surgery to repair 35 fractures of the dorsodistal radial carpal bone (n = 25), the dorsal margin of the radial facet of the third carpal bone (n = 9) and the intermediate facet of the distal radius (n = 1). There were no surgical complications and fractures healed satisfactorily in 26 of 28 horses and 23 horses returned to racing performance. Conclusion: Arthroscopically guided repair of carpal chip fractures with small diameter cortex screws is technically feasible and experiences with 33 cases suggest that this may have advantages over fragment removal in managing such cases. Potential relevance: Surgeons treating horses with large chip fractures of the carpal bones should consider arthroscopically guided internal fixation as an alternative to removal.     

刺槐根系抗弯特性研究

从根径和坡位两方面研究了石质陡边坡刺槐根系的抗弯特性。通过对刺槐根系进行室内单根弯曲试验,分析了不同坡位下坡向侧根的抗弯特性。试验结果表明,根系的抗弯强度与坡位的关系显著,不同坡位抗弯强度关系为:坡顶>坡中>坡底。坡顶和坡底根系的抗弯强度与根径之间存在递增的幂函数关系,而坡中根系抗弯强度与根径之间的关系不显著。弯曲弹性模量与根径存在递减的幂函数关系,在根径大于8mm左右,不同坡位根系弯曲弹性模量大小关系为:坡顶>坡中>坡底。不同坡位根系的最大弯曲力之间差异不显著,最大弯曲力沿着坡面向下呈递减趋势。不同坡位根系的断裂挠度之间差异也不显著,但根系的断裂挠度沿着坡面向下呈递增趋势。综合这些结果,可以发现坡顶根系的抗弯性能最佳,对边坡稳定的贡献较大。