日粮锌、硒水平对肉鸡肠道黏膜屏障结构的影响

为了探讨微量元素锌和硒相互作用对肉鸡肠道黏膜屏障结构的影响，将24只1日龄AA肉鸡随机分3组，分别饲喂添加有高锌高硒(锌1000mg／kg、硒5mg／kg)、低锌低硒(锌34mg／kg、硒0．08mg／kg)或常锌常硒(锌50mg／kg、硒0．15mg／kg)的日粮45d后，观察肠黏膜上皮细胞、上皮内淋巴细胞和盲肠扁桃体的形态结构变化。结果表明：高锌高硒或低锌低硒组肉鸡的肠黏膜结构有明显的损伤，表现为肠黏膜上皮细胞萎缩，绒毛长度下降，上皮内淋巴细胞数量减少；盲肠扁桃体的弥散淋巴组织和淋巴小结中，淋巴细胞数量减少，细胞出现肿胀，有的核消失，结缔组织增生，淋巴小结萎缩。尤其是高锌高硒组的损伤最为严重。而常锌常硒组肉鸡肠黏膜和盲肠扁桃体的形态结构正常。结论：日粮中按锌50mg／kg、硒0．15mg／kg的比例添加，对于维持肠道黏膜的正常屏障结构是合适的。过高或过低的锌和硒对小肠黏膜有毒性作用，破坏其屏障功能；而且高锌和高硒可相互促进以增强其毒性作用。     

鸡盲肠扁桃体组织结构早期发育的动态观察

本研究利用HE染色方法结合图像分析软件和数据统计软件,观察雏鸡不同生长发育阶段盲肠扁桃体的组织学发育过程和结构特征。结果显示:随着日龄的增长,盲肠扁桃体特征结构不断发育成熟,并在21日龄时基本达到成熟水平。21日龄时,盲肠扁桃体粘膜层中下部形成生发中心,其数目在35日龄时达到稳定。证实,鸡出壳后初期,盲肠扁桃体免疫功能迅速增强,并在35日龄时达到成熟水平。     

胆酸钠对山羊鼻腔相关扁桃体黏膜上皮吸收灭活病毒的影响

为研究胆酸钠促进山羊鼻腔相关扁桃体黏膜上皮吸收禽流感灭活病毒的形态学机制,经鼻腔接种胆酸钠和禽流感灭活病毒后,用组织学光镜和电镜制片技术研究山羊咽扁桃体和咽鼓管扁桃体上皮结构的变化以及灭活病毒的吸收情况。结果表明:单独应用灭活病毒后扁桃体黏膜上皮结构完整;而应用胆酸钠或胆酸钠配合灭活病毒后扁桃体中可观察到较多脱离黏膜上皮的细胞,脱落的细胞大部分是上皮细胞和淋巴细胞,上皮细胞间间隙增大,紧密连接被打开。应用胆酸钠配合灭活病毒后可观察到部分细胞内含有病毒的囊泡。鼻腔接种后第3天,应用胆酸钠的扁桃体黏膜上皮结构基本恢复,几乎没有观察到脱离上皮的细胞。结论:胆酸钠通过打开山羊鼻腔相关扁桃体黏膜上皮细胞之间的紧密连接来促进灭活病毒的吸收;虽然胆酸钠可引起部分上皮脱落,但这种副作用是短暂的并是可修复的。     

Early pathogenesis of equine Streptococcus equi infection (strangles)

Reasons for performing study: Little is known about entry and subsequent multiplication of Streptococcus equi following exposure of a susceptible horse. This information would have value in design of intranasal vaccines and understanding of shedding and protective immune responses. Objectives: To determine entry points and sites of subsequent replication and dispersion of S. equi at different times after intranasal infection or commingling exposure. Methods: Previously unexposed horses and ponies were subjected to euthanasia 1, 3, 20 or 48 h following intranasal inoculation with biotin labelled or unlabelled S. equi CF32. Some ponies were inoculated with suspensions of equal numbers of CF32 and its mutants lacking capsule, S. equi M‐like protein or streptolysin S. Others were infected by commingling exposure and subjected to euthanasia after onset of fever. Tonsils and lymph nodes were cultured for S. equi and tissues sectioned for histopathological examination and fluorescent microscopy. Results: Tonsillar tissues of both the oro‐ and nasopharynx served as portals of entry. Entry was unexpectedly rapid but involved few bacteria. Small numbers of organisms were detected in tonsillar crypts, in adjacent subepithelial follicular tissue and draining lymph nodes 3 h after inoculation. By 48 h, clumps of S. equi were visible in the lamina propria. At onset of fever, tonsillar tissues and one or more mandibular and retropharyngeal lymph nodes were heavily infiltrated by neutrophils and long chains of extracellular S. equi. Mutant S. equi lacking virulence factors were not seen in draining lymph nodes. Conclusions: Although very small numbers of S. equi entered the lingual and nasopharyngeal tonsils, carriage to regional lymph nodes occurred within hours of inoculation. This observation, together with visual evidence of intracellular and extracellular multiplication of S. equi in tonsillar lymphoid tissue and lymph nodes over the following days, indicates involvement of potent antiphagocytic activity and failure of innate immune defences. Relevance: Future research should logically address the tonsillar immune mechanisms involved including identification of effector cell(s) and antigens.     

Histological and immunohistochemical studies of the proximal caecum and caecal tonsils of quail (Coturnix coturnix japonica)

The proximal caecum in quails consists of lymphoid and non‐lymphoid structures. The caecal tonsils in the proximal part of the caecum are units of gut‐associated lymphoid tissue in poultry. This study aimed to examine the histological characteristics of the proximal caecum, as well as compositions of dendritic cells (DCs) and antigen‐presenting cells (APCs) in the caecal tonsil of quails. Tissue sections were stained with Crossman's triple, periodic acid–Schiff, Gordon and Sweet's silver, Congo red and methyl green‐pyronin dyes, as well as immunohistochemically by the streptavidin–biotin–peroxidase complex method. Caecal lymphoid tissue was located in the lamina propria and submucosa. Germinative centres were observed within the lymphoid tissue. Reticular fibres were mainly distributed in the border area of the germinal centre with only a few fibres scattered in the centre. Plasma cells were observed in the subepithelial region and germinal centres. Eosinophil granulocytes were prevalent in the lymphoid tissue. Additionally, CD83‐immunoreactive DCs and MHC class II immunoreactive APCs were present in the subepithelial area and diffuse lymphoid tissue. While DCs were seen in the germinal centres of tonsillar units, APCs were rarely present in the germinal centres, but they were noticed around the germinal centres. In conclusion, the histological structure of the proximal caecum in quails and the distributions of some immunological cells in the caecal tonsils were revealed. Therefore, the defensive role of the caecal tonsils in the digestive system may be better understood, and comparative studies may be carried out.     

山羊咽扁桃体和咽鼓管扁桃体的组织结构观察

选取健康10月龄奶山羊10头,断头宰杀后取咽扁桃体和咽鼓管扁桃体,应用组织学光镜和电镜制片技术研究咽扁桃体和咽鼓管扁桃体的显微和亚显微组织结构.结果表明:山羊咽扁桃体和咽鼓管扁桃体的黏膜上皮主要由2～3层多边形上皮细胞组成,部分区域只有单层扁平细胞,相邻上皮细胞间空隙很大,上皮细胞表面有丰富的微绒毛.上皮细胞之间和黏膜上皮下方固有层内有大量淋巴细胞浸润.扁桃体的实质部分由数个次级淋巴小结和弥散淋巴组织构成,弥散淋巴组织中有大量分布的淋巴管和毛细血管后微静脉.此外,在紧贴黏膜上皮细胞下方的固有层和淋巴滤泡中可观察到少量的树突状细胞.结果提示山羊的咽扁桃体和咽鼓管扁桃体可作为鼻腔免疫的主要诱导位点和效应部位.     

Immunophenotyping of Leukocyte Subsets in Peripheral Blood and Palatine Tonsils of Prefattening Pigs

The quantitative and distribution patterns of porcine peripheral blood and tonsillar lymphoid/myeloid cell subsets were assessed in order to establish the immune status of farm pigs prior to their transfer to fattening units. Peripheral blood and tonsillar samples were taken from clinically healthy, nonvaccinated, 12-week-old pigs, either ex vivo or following euthanasia. Single-colour flow cytometry, using monoclonal antibodies (mAbs) reactive with the swine leukocyte cluster of differentiation (CD) antigens, gave the proportions of lymphoid (9.7% CD4⁺, 8.0% CD8⁺, 36.9% CD5a⁺, 20.3% CD16⁺, 6.9% CD21⁺, 86.3% CD45⁺, 41.8% CD45RA⁺, 48.3% CD45RC⁺), null cells (6.9%) and myeloid cells (23.7% CD11b⁺ and 5.4% SWC3a⁺) in peripheral blood. In situ identification and distribution of lymphoid cells in the tonsils (CD3a⁺, CD21⁺, CD45RA⁺, CD45RC⁺) was performed with anti-CD mAbs using the avidin–biotin complex method. Most CD3a⁺ cells were in the parafollicular areas, with many cells in the follicles. CD21⁺ cells were scattered throughout the parafollicular area, with only a few cells inside lymphoid follicles. CD45RA⁺ cells were mostly concentrated in the follicles but many positive cells were present in the parafollicular area. Many CD45RC⁺ cells were visible in the parafollicular area, a few positive cells were in the crypt epithelium, and single cells were inside the follicles.     

Suboccipital craniectomy, dorsal laminectomy of C1, durotomy and dural graft placement as a treatment for syringohydromyelia with cerebellar tonsil herniation in Cavalier King Charles spaniels

OBJECTIVE: To evaluate retrospectively the efficacy of the suboccipital craniectomy and dorsal laminectomy of C1 with durotomy and placement of a dural graft for treatment of syringohydromyelia (SHM) because of cerebellar tonsil herniation in Cavalier King Charles spaniels (CKCS). This technique is used with great success in human medicine. STUDY DESIGN: Four CKCS diagnosed by Magnetic resonance imaging (MRI) of SHM because of cerebellar tonsil herniation and not responsive to medical therapy underwent a suboccipital craniectomy and dorsal laminectomy of C1 (2 dogs) and of C1 and partial C2 (2 dogs) with durotomy and placement of a dural graft. Three dogs were evaluated neurologically 24 hours, 1 month, and 3 months postoperatively and evaluations were compared with preoperative neurological examination. Repeat MRI took place 3 months postoperatively. RESULTS: Neurological examinations showed neither improvement nor progression of clinical signs 3 months postoperatively. MRI showed no regression of syrinx size 3 months postoperatively. CONCLUSION: Improvement was not seen. Given the progressive nature of the disorder, evaluation over a longer period of time is necessary to detect if progression has stopped. Some modification to the surgical technique is needed to accomplish the same results as in human medicine. A study of a larger population is needed to attain more reliable information. CLINICAL RELEVANCE: Suboccipital craniectomy and dorsal laminectomy of C1 with durotomy and placement of a dural graft is a feasible technique in CKCS, but needs some modification to accomplish the same results as in human medicine.     

Observations on mortality of young dogs in New Zealand

Changes in the plasma concentrations of cortisol were recorded in 5–6 weeks-old lambs during the first 480 minutes after surgical castration and tailing in order to define the full post-treatment cortisol response and to determine whether or not the handling associated with repeated blood sampling delayed the return of cortisol concentrations to pretreatment values. Four groups of six or seven lambs were studied: One group was bled regularly throughout the 480 minutes of the study, and in the other three post-treatment blood sampling began at 90, 240 or 480 minutes. Plasma cortisol concentrations increased after treatment and returned to or approached pretreatment values by 480 minutes. No significant differences in mean cortisol concentrations were observed between the groups at any stage. It is concluded that the acute distress response of these lambs to surgical castration and tailing lasted about 8 hours and that repeated handling for blood sampling did not contribute significantly to this distress.