Evaluation of neutrophil oxidative metabolism in canine monocytic ehrlichiosis

BACKGROUND: Canine monocytic ehrlichiosis (CME) is a tick-borne disease caused by Ehrlichia canis, a rickettsia that infects the monocytes of dogs. This infection can result in a chronic and life-threatening disease. Thrombocytopenia, mild anemia, and leukopenia are the most common hematologic findings in CME. OBJECTIVE: To investigate the role of peripheral blood neutrophils in CME, an evaluation was conducted of their functional state during the acute phase of the disease in dogs experimentally infected by E canis. METHODS: Seven dogs were inoculated with E canis, and 3 remained as uninfected controls. All dogs had physical exams and hematologic tests (CBC and nitroblue tetrazolium [NBT] reduction) during a 6-week period. RESULTS: There was no difference (P > .05) in spontaneous NBT reduction results between the 2 groups of dogs throughout the 6-week period of observation. Nevertheless, when stimulated, the neutrophils showed higher activity in the infected group (P = .01) on weeks 4 and 5 after infection. CONCLUSION: Infection by E canis has no influence on neutrophil oxidative metabolism even though during the remission period of the acute phase of the disease, the neutrophils seem to be more reactive under stimulation.     

Effects of pasteurella haemolytica leukotoxin on neutrophils from white-tailed deer and several exotic ruminant species

Pasteurella haemolytica leukotoxin is a pore-forming cytolysin which acts as a virulence factor in pasteurellosis of domestic ruminants. Leukocytes from cattle, sheep and goats are susceptible to leukotoxin-induced lysis; however, leukocytes from non-ruminant species so far tested are resistant to leukotoxin-induced lysis. Neutrophils obtained from three white-tailed deer, four Saiga antelope, an Addra gazelle, a Grant's gazelle and a Sable antelope were tested for susceptibility to the lytic effects of P. haemolytica leukotoxin using lactate dehydrogenase release. Results were compared to those obtained using neutrophils from a steer and cultured bovine lymphoma cells. Neutrophils obtained from all these ruminants, except the Addra gazelle, were susceptible to P. haemolytica leukotoxin. Individual variation among the Saiga and the deer did not appear to be due to the percentages of neutrophils or the percentage of contaminating erythrocytes in the cell preparations.     

禁食对大鳞副泥鳅形态学及各型白细胞百分比的影响

为探究大鳞副泥鳅(Paramisgurnus dabryanus)对饥饿胁迫的响应,测定了自由取食组、禁食3 d组、7 d、21 d和28 d组其体重与体长的比值(重长比)、比肝重和比脾重指数、各型白细胞的百分比及嗜中性粒细胞与淋巴细胞(N/L)的比值的变化。重长比随饥饿时间延长呈下降趋势,但组间差异不显著(P0.05);比脾重无组间差异(P0.05),比肝重在禁食21d后显著下降(P0.05)。单核细胞的百分比自由取食组显著高于禁食21d组(P0.05);嗜中性粒细胞和淋巴细胞的百分比自由取食组与其他组间均无显著差异,但嗜中性粒细胞的百分比禁食21 d组显著高于禁食21 d、7 d和28 d组(P0.05),淋巴细胞的百分比禁食21 d组显著低于禁食7 d和28 d组(P0.05)。N/L的比值自由取食组与其他组间均无显著差异,但禁食21 d组显著高于禁食7 d和28 d组(P0.05)。结果表明,大鳞副泥鳅通过降低的重长比和比肝重来响应禁食的影响,各型白细胞的百分比和N/L的比值的变化趋势多样,这可能与各自的生理功能有关。     

猪呼吸道疾病综合征中性粒细胞cAMP-PDE和血浆cAMP、IL-6、TNF-α的变化及中药疗效研究

本试验通过观察呼吸道疾病综合征（PRDC）病猪中性粒细胞（PMN）环磷酸腺苷磷酸二酯酶（cAMP-PDE）活性和血浆cAMP、白介素-6（IL-6）、肿瘤坏死因子-α（TNF-α）含量的变化及自拟中药汤剂对其的影响与疗效,以期为呼吸道炎症的病理机制与中药防制积累资料。将PRDC病猪随机分组,治疗组灌服由芦根、黄芪、白芍、甘草组成的1 g生药/mL中药,1.5 mL/kg,每天2次,连续给药10 d。停药后取全血检测各组外周血白细胞数量;并分离PMN,HPLC法检测cAMP-PDE活性;ELISA试剂盒测定血浆中cAMP、IL-6、TNF-α的含量。与健康对照组相比,患病组白细胞数量显著升高（P<0.05）,cAMP-PDE活性和血浆TNF-α、IL-6含量均极显著升高（P<0.01）;治疗组TNF-α含量显著升高（P<0.05）。与患病组相比,治疗组的白细胞数量、cAMP-PDE活性和血浆TNF-α含量均显著降低（P<0.05）,IL-6极显著降低（P<0.01）。结果表明PRDC病猪存在外周血白细胞数量、PMN cAMP-PDE活性和血浆IL-6、TNF-α含量升高的异常变化,自拟中药汤剂能改善呼吸道病猪的临床症状,其作用机制与降低白细胞数量,抑制PMN cAMP-PDE活性和降低血浆IL-6、TNF-α含量相关。     

Descriptive results from a longitudinal study of airway inflammation in British National Hunt racehorses

Reasons for performing study: Rates of airway inflammation in young racehorses decrease with time but it is not clear whether this is associated with increasing age or time exposed to the training environment. The structure of the British National Hunt (NH) population allowed closer examination of this relationship. Objectives: To compare rates of inflammatory airway disease diagnosed by tracheal sampling (trIAD), and its components, in NH racehorses by age and training history and with published rates in young racehorses. Methods: A prospective, longitudinal study was conducted on 5 NH yards over 2 years. Period sample prevalences of nasal discharge, tracheal mucus, airway neutrophilia and trIAD (defined by a combination of tracheal mucus and airway neutrophilia) were estimated and compared between horses with different ages and time in training. Results: Horses new to training had twice the odds of visible tracheal mucus as ex‐flat trained horses (OR 2.0; 95% CI: 1.4–2.8; P<0.001) but no significantly increased odds of airway neutrophilia (OR 1.3; 95% CI: 0.8–1.9; P = 0.3) and inconclusive evidence of increased odds of trIAD (OR 1.8; CI: 0.9–3.5; P = 0.08). However, a lower median time in training was significantly associated with the presence of visible mucus (P<0.001), increased mucus (P = 0.005) and trIAD (P = 0.03). No disease measure varied significantly with age. Conclusions: Tracheal mucus and trIAD, but not neutrophilia detected in tracheal wash samples, were less prevalent in horses that had been exposed to the training environment for longer, explaining previously reported associations with age. Potential relevance: Neutrophil proportion in tracheal wash samples is not as useful a clinical tool as measures of visible tracheal mucus for identifying horses requiring treatment or changes in management. The inclusion of tracheal wash neutrophils in the assessment of equine airways, or at least their relative weighting in definitions of trIAD, should be re‐evaluated.     

转移因子免疫学活性的影响

分别给成年健康小鼠口服和注射不同剂量的转移因子 (Transfer factor,TF) ,第 8天检测小鼠外周血中性粒细胞对葡萄球菌的吞噬率 ,第 11天检测小鼠腹腔巨噬细胞对鸡红细胞的吞噬率。结果表明 ,无论是口服还是注射 TF,均可使小鼠外周血中性粒细胞和腹腔巨噬细胞的吞噬率提高 ,且显著高于对照组 (P<0 .0 5 )并且在一定范围内 ,其吞噬率的高低与 TF剂量呈正相关 ,但 TF对小鼠脾重影响不显著 (P>0 .0 5 )。用 TF协同鸡血清免疫家兔 ,结果显示试验组抗体效价显著高于对照组 (P<0 .0 1)     

The Effect of Dexamethasone on Some Immunological Parameters in Cattle

Immunosuppression as a consequence of acute and chronic stress can increase the susceptibility of cattle to a range of infectious diseases. In order to develop a panel of immune function assays for investigating the effects of potential stressors on immune competence in cattle, the effect of treatment with short- and long-acting preparations of the synthetic glucocorticoid dexamethasone was examined. Short-acting dexamethasone (dexamethasone sodium phosphate 0.08 mg/kg) followed 37 h later by long-acting dexamethasone (dexamethasone-21 isonicotinate 0.25 mg/kg) was injected intramuscularly and blood was collected to assess immune functions at intervals over the subsequent 11 days from 6 treated and 6 control Hereford steers. Dexamethasone induced leukocytosis (neutrophilia, eosinopenia, lymphopenia, monocytosis), an increased neutrophil:lymphocyte ratio, an elevated percentage of CD4⁺ lymphocytes, a decreased total CD8⁺ lymphocyte count, decreased total and percentage WC1⁺ lymphocytes, an elevated percentage of IL-2 receptor alpha (IL-2R)⁺ lymphocytes, and an elevated percentage of B lymphocytes. In vitro chemotaxis of peripheral blood neutrophils to human C5a and ovine IL-8 was increased by dexamethasone treatment. Lymphocyte proliferation in the presence of phytohaemagglutinin, and serum concentrations of IgM, but not IgA or IgG1, were suppressed by dexamethasone treatment, whereas mitogen-induced production of interferon- (IFN-), neutrophil expression of CD18, neutrophil myeloperoxidase activity and natural killer (NK) cell activity were not influenced by dexamethasone treatment. The results indicate the potential for haematology and immune function assays to reflect elevated activity of the hypothalamic–pituitary–adrenocortical axis in cattle. Immunological parameters may thus provide a useful adjunct to cortisol and behavioural observations for assessing the impact of stress on the welfare of cattle.