The disposition and local effects of intra-articular morphine in normal ponies

Morphine (15 mg in 5 ml saline) was injected into the left, and 5 ml saline into the right, tarsocrural joint of 8 ponies. Venous blood samples were collected before and at 0.5, 1, 2, 6 and 24 h after the intra-articular morphine injection and analysed for morphine and its metabolites. Synovial fluid was sampled from both tarsocrural joints before and 24 h after injection. Synovial white blood cell and red blood cell counts, protein and hyaluronate concentrations were measured in all the samples; and the synovial fluid morphine concentration from the left tarsocrural joint was measured 24 h after the injection. The peak mean plasma morphine concentration (7.1 μg/l) was detected in samples taken 0.5 h after the intra-articular morphine injection, but neither morphine nor its metabolites were found in plasma 6 h or more post injection. Morphine was detected in the synovial fluid of each pony 24 h after the injection. The plasma morphine or morphine-6-glucuronide concentrations were lower than those likely to have any systemic effect. The synovial fluid white blood cell count and protein concentration were increased and hyaluronate concentration decreased in samples taken 24 h after the intra-articular morphine injection, compared to the pre-injection samples. No differences were found between morphine and saline injected joints. It was concluded that morphine did not irritate the joint more than saline.     

Investigation of diagnostic importance of platelet closure times measured by Platelet Function Analyzer--PFA 100 in dogs with endotoxemia

This study was performed to evaluate the diagnostic importance of the platelet closure times measured by the Platelet Function Analyzer (PFA-100) in dogs with endotoxemia. E. coli endotoxin was given intravenously once, at the dose of 0.02 mg/kg or 1 mg/kg in groups I (n=9) and II (n=8), respectively. Normal saline (0.1 ml/kg) was injected in group III (n=8).The dogs were monitored for 48 h, and venous blood samples were collected prior to (baseline) and at intervals of 0.5, 1, 2, 4, 6, 8, 12, 24 and 48 h subsequent to the treatments. The white blood cell (WBC), platelet counts, and hematocrit (Hct) values were recorded. Platelet closure times were determined, using collagen/epinephrine (CEPI) and collagen/adenosine diphosphate (CADP) cartridges. Within 0.5 h after the endotoxin application baseline WBC and platelet counts (mean +/-SD) decreased significantly (p<0.001) to 2000 +/- 500 and 1850 +/- 200 cells/microl or 69.000 +/- 12.500 and 27.000 +/- 6.400 cells/microl in groups I and II, respectively. Platelet counts remained low during the first 1-48 h, but the WBC count was high at the 8th-48th h, in groups I and II, compared with baselines (p<0.001). After the application of the endotoxin, Hct values increased from baseline values of 37 +/- 3 or 39 +/- 2% to 48 +/- 2 or 51 +/- 3%, within 1 h (p<0.001), in groups I and II, respectively. Hct values in group II were notably higher (p<0.001) than those of group I, during the 2nd-48th h. Hematological parameters and closure times did not differ significantly throughout the study in group III. Baseline closure time ranged from 79 +/- 5 seconds (s) to 86 +/- 5 s for CADP and 144 +/- 13 s to 159 +/- 14 s for CEPI in all dogs (n=25). At 0.5 h after the endotoxin, the closure times of CADP as well as CEPI declined to 62 +/- 6 s and 76 +/- 8 s in group I (p<0.001) and 57 +/- 5 s and 75 +/- 6 s in group II (p<0.001). Afterwards, closure time prolonged to the levels of 280 +/- 8 s (CADP) and 294 +/- 5 s (CEPI) by 48 h (p<0.001) in group II, but returned to the baseline limit in group I. In conclusion, our results show that the shortened closure times may serve as a very early diagnostic sign of endotoxemia, prolonged closure times however may be used as an index for the severity of endotoxemia.     

Pneumonia in lambs inoculated with Bordetella parapertussis: bronchoalveolar lavage and ultrastructural studies

Eight colostrum-deprived lambs were inoculated intratracheally with ovine isolates of Bordetella parapertussis. Fluids obtained by bronchoalveolar lavage had a large increase in total cell counts 24 hours after inoculation; up to 93% of cells were neutrophils. From 3 days after inoculation, the number of alveolar macrophages in lavage samples was markedly increased. From 5 days onwards, many alveolar macrophages had moderate to severe cytoplasmic vacuolation. Topographically, tracheal and bronchial epithelium was covered by a large amount of inflammatory exudate 24 hours after inoculation. Later, the tracheobronchial epithelium showed focal extrusions from ciliated cells, which were occasionally associated with B. parapertussis organisms. Ultrastructurally, cytopathological changes associated with B. parapertussis infection were mild focal degeneration of airway epithelium with slight loss of cilia, moderate to severe degeneration of type I and type II alveolar epithelial cells, and focal inflammation in the lungs. These results suggest that the primary targets of B. parapertussis infection are alveolar macrophages and the epithelial cells of bronchioles and alveoli.     

紫花苜蓿种带阪崎克罗诺杆菌的分离鉴定及其致病性初步研究

采用稀释平板法从6种表面消毒的紫花苜蓿种子中分离和纯化出3株阪崎克罗诺杆菌疑似分离物。选取代表分离物1gF3室内条件下通过菌悬液(≈10⁹ cfu·mL^-1)浸种紫花苜蓿种子,皿内发芽;腹腔注射洁净级昆明小白鼠试验;测定阪崎克罗诺杆菌疑似分离物对紫花苜蓿和小鼠的致病性。结果表明,阪崎克罗诺杆菌疑似分离物对紫花苜蓿不致病;小鼠在接种分离物1gF3 12 h后病理特征显示化脓性脑炎、心肌水肿扩张,局部心肌纤维有断裂、肝脏局部坏死、急性脾炎、肺部急性弥散性出血以及肾脏弥散性血管内凝血等症状,1gF3对小鼠具有致病性。发病小鼠血液涂板分离到阪崎克罗诺杆菌疑似分离物TM2。结合表型特征和16S rDNA鉴定,确定分离物1gF3和TM2为阪崎克罗诺杆菌。在此基础上,测定了菌株1gF3的生物学特性,该菌对数生长期为24~36 h,之后衰退;干旱胁迫加重其生长量线性下降;菌株1gF3能在较宽温度(10~41 ℃)和pH (3~11)范围内生长;该菌不需盐生长,NaCl浓度上升该菌的生长量受到抑制;黑暗交替的光照有利其生长。研究材料为具有动物和植物跨域寄主特点的一类病原菌资源,研究结果对隐藏于植物或动物材料中跨域病原菌侵染传播特征及相关检疫防控提供了理论基础。     

The effect of selected antibiotics on microorganisms contaminating boar ejaculate]

The occurrence of microorganisms, including their total counts in boar native ejaculates, was investigated in two stages; the objective of this investigation also was to determine contamination after the sperms were treated with diluents containing the antibiotics ampicillin, gentamycin, apramycin, cefoxitin, or antibiotic combinations penicillin + streptomycin, ampicillin + cefoxitin, gentamycin + cefoxitin and ampicillin + gentamycin. The representation of bacterial species and total counts of microbes in 1 ml diluted sperm stored at a temperature of about 18 degrees C were determined in 24, 48 and 72 h after dilution. The microorganisms were cultivated from all native ejaculates. Proteus sp. (63.3%) and Pseudomonas aeruginosa (51.5% of the total number of examined samples) were the most frequent species. The number of contaminated diluted ejaculates ranged from 12.5 to 95.8% in 24 h after dilution, from 12.5 to 98.5% in 48 h and from 16.8 to 95.8% of the total number of examined ejaculates in 72 h. The occurrence of microorganisms correlated mostly with the efficiency spectrum of the antibiotics or their combinations. The average counts of microorganisms in 1 ml of native ejaculate made 2,363,000 in stage I and 1,472,108 in stage II. The highest average counts in 1 ml of diluted sperm were found in ejaculates containing cefoxitin and apramycin. Gentamycin was the most effective antibiotic used as a sole component (average counts of microorganisms CPM in 1 ml were 416 in 24 h, 955 in 48 h and 2260 in 72 h after dilution); ampicillin and gentamycin were the most efficient combination (14--20--21). This combination exerted very good effects also on Proteus sp. and Pseudomonas aeruginosa.     

Effect of time delay and storage temperature on blood gas and acid-base values of bovine venous blood

The aim of this study was to investigate possible changes in the gas composition and acid-base values of bovine venous blood samples stored at different temperatures (+4, 22 and 37 degrees C) for up to 48 h. Five healthy cattle were used in the study. A total of 15 blood samples collected from the animals were allocated into three groups, which were, respectively, then stored in a refrigerator adjusted to +4 degrees C (Group I, n=5), at a room temperature of about 22 degrees C (Group II, n=5) and in an incubator adjusted to 37 degrees C (Group III; n=5) for up to 48 h. Blood gas and acid-base values were analysed at 0 (baseline), 1, 2, 3, 4, 5, 6, 12, 24, 36 and 48 h of storage. A significant decrease (p<0.001) was found, in the pH of the refrigerated blood after 5 h and its maximum decrease was recorded at 48 h as 0.04 unit. There were also significant alterations (p<0.001) in the blood pH of the samples stored at room temperature and in the incubator after 2 and 3 h, respectively. The maximum mean alteration in pCO(2) value for Group I was -0.72 kPa during the assessment, while for groups II and III, maximum alterations in pCO(2) were detected as +2.68 and +4.16 kPa, respectively. Mean pO(2) values increased significantly (p<0.001) for Group I after 24 h and for Group II after 6 h, while a significant decrease was recorded for Group III after 24 h (p<0.001). Base excess (BE) and bicarbonate (HCO(3)) fractions decreased significantly for all the groups during the study, compared to their baseline values. In conclusion, acid-base values of the samples stored at 22 and +4 degrees C were found to be within normal range and could be used for clinical purposes for up to 12 and 48 h, respectively, although there were small statistically significant alterations.     

Evaluation of iatrogenic hemarthrosis of the metacarpophalangeal joint as a method of induction of temporary reversible lameness in horses

OBJECTIVE: To determine whether iatrogenic hemarthrosis of the metacarpophalangeal joint could be used as a model for temporary reversible joint pain in horses. ANIMALS: 8 adult horses. PROCEDURE: Each horse was evaluated on a treadmill before and after injection of 1 metacarpophalangeal joint with 10 mL of autogenous blood. Horses were evaluated subjectively and objectively by use of a computerized force measurement system at intervals until lameness abated. The mean force difference between injected and noninjected limbs at all time periods after injection was compared with the difference between limbs at baseline. From each horse, synovial fluid samples collected before and 24 hours and 30 days after injection were analyzed for total protein concentration and cell type and number. Venous blood samples were collected before and 6 and 24 hours after injection for assessment of plasma cortisol concentration. RESULTS: For 24 hours after injection, the mean force difference between injected and noninjected limbs was significantly increased over baseline. The greatest force difference was detected after 2 and 4 hours. Baseline and 24-hour force data were not significantly different. Compared with baseline values, synovial fluid protein concentration and nucleated cell and RBC counts were increased significantly at 24 hours after injection but were not different at 30 days after injection. No significant changes in plasma cortisol concentration were detected at any time point. CONCLUSIONS AND CLINICAL RELEVANCE: In horses, iatrogenic hemarthrosis of the metacarpophalangeal joint appears to induce temporary reversible lameness with a mild to moderate degree of synovitis.     

Effects of bacterial lipopolysaccharide injection on white blood cell counts, hematological variables, and serum glucose, insulin, and cortisol concentrations in ewes fed low- or high-protein diets

Bacterial lipopolysaccharide endotoxins (LPS) elicit inflammatory responses reflective of acute bacterial infection. We determined if feeding ewes high-CP (15.5%) or low-CP (8.5%) diets for 10 d altered inflammatory responses to an intravenous bolus of 0 (control), 0.75 (L75), or 1.50 (L150) μg of LPS/kg of BW in a 2 × 3 factorial arrangement of treatments (n = 5/treatment). Rectal temperatures, heart and respiratory rates, blood leukocyte concentrations, and serum cortisol, insulin, and glucose concentrations were measured for 24 h after an LPS bolus (bolus = 0 h). In general, rectal temperatures were greater (P ≤ 0.05) in control ewes fed high CP, but LPS increased (P ≤ 0.05) rectal temperatures in a dose-dependent manner at most times between 2 and 24 h after the bolus. Peak rectal temperatures in L75 and L150 occurred 4 h after the bolus. A monophasic, dose-independent increase (P ≤ 0.023) in serum cortisol occurred from 0.5 to 24 h after the bolus, with peak cortisol at 4 h. Serum insulin was increased (P ≤ 0.016) by LPS in a dose-dependent manner from 4 to 24 h after the bolus. Insulin did not differ between control ewes fed high- and low-CP diets but was greater (P < 0.001) in L75 ewes fed low CP compared with high CP and in L150 ewes fed high CP compared with low CP. Increased insulin was not preceded by increased serum glucose. Total white blood cell concentrations were not affected (P ≥ 0.135) by LPS, but the neutrophil and monocyte fractions of white blood cells were increased (P ≤ 0.047) by LPS at 12 and 24 h and at 24 h after the bolus, respectively, and the lymphocyte fraction was increased (P = 0.037) at 2 h and decreased (P ≤ 0.006) at 12 and 24 h after the bolus. Red blood cell and hemoglobin concentrations and hematocrit (%) were increased (P ≤ 0.022) by LPS at 2 and 4 h after the bolus. Rectal temperatures and serum glucose were greater (P ≤ 0.033) in ewes fed a high-CP diet before LPS injection, but these effects were lost at and within 2.5 h of the bolus, respectively. Feeding high-CP diets for 10 d did not reduce inflammation in ewes during the first 24 h after LPS exposure but may benefit livestock by preventing acute insulin resistance when endotoxin exposure is mild.     

Adherence of Haemophilus somnus to tumor necrosis factor-alpha-stimulated bovine endothelial cells in culture.

Vascular thrombosis and tissue infarction is a principal lesion in Haemophilus somnus septicemia known also as thrombotic meningoencephalitis. This study was undertaken to examine whether tumor necrosis factor-alpha (TNF-alpha) can influence the adherence of H. somnus to cultured bovine aortic endothelial cells (BAEC). Confluent BAEC were exposed to 0-100 nM of human recombinant TNF-alpha for 12-48 h. Suspensions of different strains of H. somnus (approximately 1.5-3 x 10(8) labelled with [methyl-3H]-thymidine, were added to BAEC and incubated for 1.5 h. Initial studies with one pathogenic (P) strain and one non-pathogenic (NP) strain revealed that both strains adhered to normal endothelial cells but minimally to subendothelial matrix remaining after removal of BAEC. Adherence to BAEC was reduced by an excess of unlabelled H. somnus of the same strain. Adherence was enhanced for both strains by exposure of BAEC to TNF-alpha in a manner that increased with TNF-alpha concentration and with duration of exposure to TNF-alpha prior to addition of bacteria. A survey of adherence of six live P strains and six NP strains demonstrated considerable variation but no difference in adherence between P and NP strains to normal or to TNF-alpha-stimulated BAEC. However, TNF-alpha consistently increased adhesion of each strain to BAEC. Both P and NP strains caused more severe cytotoxic changes in TNF-alpha-treated BAEC. Tumor necrosis factor-alpha also increased adhesion of formalin-killed bacteria of P and NP strains.(ABSTRACT TRUNCATED AT 250 WORDS)     

Development and validation of a tissue cage model of acute inflammation in the cat

Four cylindrical silicon tissue cages (TC, internal volume: 6.7 ± 0.11 cm(3)) were inserted subcutaneously in 29 young healthy cats. A mild inflammatory reaction was induced by intracaveal injection of 1 mL of a 2%λ-carrageenan solution. TC exudate was subsequently sampled at predetermined times (up to 120 h) to measure exudate leucocyte counts and the concentrations of protein and eicosanoids. TC remained in situ for 9-10 months and were well tolerated. Leucocyte counts peaked at 34 h (50.1 ± 57.6 × 10(3) cells/mm(3) ) and returned towards baseline after 72 h. Protein concentration increased from 26.2 ± 2.7 g/L to a peak of 35.9 ± 6.0 g/L at 12 h before returning to baseline at 48 h. Exudate prostaglandin (PG)E(2) concentration peaked at 24 h (11.7 ± 13.7 ng/mL) and returned to baseline by 120 h. Repeated collection of fluid from noninjected cages did not increase transudate PGE(2). Ketoprofen (2 mg/kg, subcutaneously) suppressed exudate PGE(2) at 24 h. The carrageenan-stimulated TC model is an ethical and novel means of investigating soft tissue inflammation in the cat, in which exudate PGE(2) acts as surrogate marker of cyclooxygenase-2 activity. This model will facilitate the investigation of in vivo pharmacokinetics and pharmacodynamics of anti-inflammatory drugs in this species.     

The effect of the lactation period on the cell content of sheep milk]

Milk samples of 201 ewes were examined in 6 week intervals during a complete lactation period. Those samples were analyzed for the presence of pathogenic bacteria and the somatic cell count was determined. Besides, the California Mastitis Test (CMT) was performed and the udder was clinically examined. The cell counts were found to depend on the lactation period. During 6 weeks following parturition the cell count was 63,000 cells/ml. This number decreased towards the 24th week of lactation to 32,000 cells/ml. At the end of lactation this value increased again to 425,000 cells/ml. The median value of ewes with normal udder health was 56,000 cells/ml milk. For samples from which pathogenic bacteria were isolated this value was 159,000 cells/ml. The most frequent pathogens isolated from the milk samples were coagulase-negative cocci (59.6% of bacteriologically positive samples), the median number being 88,000 somatic cells/ml in these sheep. Coagulase-positive cocci were isolated in 25.3% of the samples, the median value of the cell count was 295,000 cells/ml. In 12.1% of the samples streptococci were found. The median value was 167,000 cells/ml. From the remaining 3.0% of bacteriologically positive samples Pasteurellae, E. coli and Actinomycetae were isolated. The median value of the somatic cell count was 184,000 cells/ml. We consider coagulase-positive cocci therefore as the most pathogenic bacteria for the ovine udder.     

The phagocytic cell response of the ovine lung to Pasteurella haemolytica

Conventionally-reared sheep were inoculated with (3.0 ± 0.6 × 10⁷) viable Pasteurella haemolytica type A1 by the intratracheal route and were killed immediately (0-time) or 2, 4, 12, 16, 24, 48 or 72 h later. Lung-wash cells and free bacteria were recovered by pulmonary layage.The number of recoverable bacteria tended to increase between 0-time and 4 h post-in-oculation (p.i.) then decline rapidly over the next 8 h. However, the rate of clearance was extremely variable and viable bacteria were recovered from $\text{3}\text{5}$ animals at 48 h p.i. and from $\text{1}\text{5}$ at 72 h p.i.In parallel with the clearance of the majority of the bacteria, total neutrophil numbers in the lung-wash rose to a peak of (36 ± 6) × 10⁸ cells/lung, which was, on average, 70-fold higher than 0-time levels. Their numbers remained constant from 12 to 24 h p.i. then fell to be 5-fold above 0-time levels at 72 h p.i. Macrophage numbers rose slowly throughout the experiment but most of the increase occurred between 24 and 48 h p.i. They reached a peak of (17 ± 11) × 10⁸ cells/lung at 48 h i.p. which was 3-fold higher than 0-time levels.     

Pulmonary eosinophilia and granulomatous pulmonary arteritis induced in rats by intravenous Sephadex.

Airway eosinophilia has been proposed as a major pathogenetic event in bronchial asthma and airway hyperresponsiveness. Intravenous injection of Sephadex G200 in rats induces pulmonary and blood eosinophilia and alters pulmonary responsiveness to 5-hydroxytryptamine. To characterize the early pulmonary inflammatory responses following Sephadex administration, and to determine the timing of the onset of pulmonary eosinophilia relative to blood eosinophilia, Sprague-Dawley rats were injected intravenously with Sephadex G200 beads. Lungs and other tissues were examined by light and transmission electron microscopy at 4, 12, 24, 48, 72, and 96 hours after injection. Blood eosinophil counts were determined at 0, 24, and 96 hours after injection. Sephadex beads were trapped initially in small caliber muscular pulmonary arteries associated with terminal bronchioles and in intra-acinar locations. There was marked infiltration of eosinophils and macrophages around the beads and into arterial walls and edematous periarterial and peribronchiolar connective tissue as early as 4 hours after injection. Periarterial-peribronchiolar eosinophil aggregates peaked in density at 24 and 48 hours. Macrophages and multinucleated cells dominated the inflammatory cell responses in arteries immediately surrounding partially degraded Sephadex beads from 24 to 96 hours. Bone marrow eosinophilopoiesis and blood eosinophilia were not detected until 96 hours. We conclude that Sephadex induces pulmonary eosinophilia prior to blood eosinophilia and suggest that Sephadex may induce pulmonary release of one or more eosinophil chemotactic substance(s). This model may prove useful in the study of factors that influence eosinophil migration into the lung in various disease states.     

沙门菌感染对小鼠白细胞总数及其亚群动态变化的影响

为研究沙门菌感染对小鼠白细胞总数及其亚群动态变化的影响,采取腹腔注射的方法给小鼠接种6.5×10⁹ CFU/mL浓度的沙门菌0.1 mL/只,分别在4、6、8、12、16和24 h采集小鼠血液,应用全自动动物血液细胞分析仪检测感染小鼠的白细胞总数、淋巴细胞数、单核细胞数和粒细胞数,记录并分析小鼠24 h内白细胞总数及其亚群的动态变化。结果表明：模型组小鼠白细胞总数及其亚群均呈先升高后降低的趋势,且白细胞总数和粒细胞数的变化幅度最明显,与空白对照组比较差异极显著（P<0.01）。说明感染沙门菌能够刺激小鼠机体产生免疫应答,影响血液中白细胞总数及其亚群的动态变化。     

Competitive exclusion of Yersinia enterocolitica biotype 4, serotype O:3 by Yersinia enterocolitica biotype 1A, serotype O:6,30 in tissue culture and in pigs

AIMS: To study the adhesion properties of a biotype 4, serotype O:3 (human pathogenic) strain of Yersinia enterocolitica and to determine if adhesion in vitro and colonisation in vivo can be prevented by competition with a biotype 1A, serotype O:6,30 (non-pathogenic) strain. To study interaction between Y. enterocolitica biotype 4, serotype O:3 and cultured epithelial cells using the synthetic tripeptide arginine-glycine-aspartic acid (RGD). METHODS: The human intestinal epithelial (HEp-2) cell line was used for in vitro studies. Inocula of Y. enterocolitica biotype 4, serotype O:3 radiolabelled using tritium were incubated with HEp-2 cells and RGD tripeptide, or with Y. enterocolitica biotype 1A, serotype O:6,30 sequentially or concurrently, then washed and lysed, and radioactivity measured to determine the effect of RGD on adhesion, and competitive exclusion of pathogenic by non-pathogenic bacteria. For in vivo studies, two groups of 5-week-old piglets (n=5/group) were sequentially inoculated orally with 5 x 10(9) colony forming units (cfu) of either a non-pathogenic biotype 1A, serotype O:6,30 strain of Y. enterocolitica followed by a pathogenic biotype 4, serotype O:3 strain, or vice versa. Pigs were monitored for carriage of strains using bacterial culture and a multiplex polymerase chain reaction (PCR). RESULTS: The RGD tripeptide significantly inhibited adherence of the pathogenic Y. enterocolitica strain to cultured epithelial cells, suggesting that adhesion involved the RGD tripeptide sequence. The non-pathogenic biotype 1A, serotype O:6,30 strain of Y. enterocolitica prevented adhesion of the pathogenic strain to cells in vitro when allowed to adhere first. Pathogenic Y. enterocolitica was consistently isolated from rectal swabs from 80-100% of pigs on all sampling occasions but not from oral swabs after 14 days in pigs first inoculated with the non-pathogenic strain or at 26 days in pigs first inoculated with the pathogenic strain. CONCLUSIONS: A non-pathogenic strain of Y. enterocolitica reduced adhesion of a human pathogenic strain in vitro but not in vivo.     

Effect of simulated ambient particulate matter exposure on performance, rectal temperature, and leukocytosis of young Spanish goats with or without tilmicosin phosphate

Dust is an environmental stressor and can become extensive in agricultural production systems. Thirty-six female, Spanish goats (average BW 21.1 kg, SEM = 1.31; age = 4 mo) were randomly assigned to simulated dust events or no dust, with or without tilmicosin phosphate treatment in a 2 x 2 factorial arrangement of treatments to determine effects on performance, rectal temperature, and leukocyte changes. All goats were fed a standard growing diet (13.6% CP) consisting of 37% roughage and 63% concentrate (DM basis). Feed intake was measured daily, and BW (unshrunk) measured individually every 7 d. The tilmicosin-treated group received tilmicosin phosphate (10 mg/kg BW s.c.) before starting the study. Goats exposed to dust were enclosed as a group inside a canvass tent for 4 h each day and ground feed yard manure dust (mean particle size 100 microm) was aerosolized inside the tent to simulate a dust event. There was one single dust event (Phase I) followed by rectal temperature measurement, and heparinized blood collection for complete cell counts at 0 (pretrial), 4, 12, 20, 44, 68, and 210 h after dust exposure. This was followed by 21 d of chronic dust events (Phase II). The sampling procedures for Phase II were exactly the same as in Phase I, except that samples were obtained daily at 0 (before dust application), 4, 8, and 12 h after each dust event. Dust treatment had no effect (P > 0.05) on feed intake or ADG, but the gain:feed (G:F) ratio was lower (P < 0.05) in the control goats than the dust exposed group. Tilmicosin phosphate-treated goats had a higher (P < 0.05) G:F ratio than untreated goats. Dust exposure increased (P < 0.002), but tilmicosin treatment decreased (P < 0.05) rectal temperature at 4 and 8 h. Dust exposure increased (P < 0.02) blood lymphocyte counts compared with controls. These results suggest that simulated dust events altered rectal temperature and leukocyte counts of goats.     

The effects of pentoxifylline infusion on plasma 6-keto-prostaglandin F1α and ex vivo endotoxin-induced tumour necrosis factor activity in horses

Pentoxifylline (7.5 mg/kg) was bolused intravenously to eight healthy horses and was immediately followed by infusion (1.5 mg/kg/h) for 3 h. Clinical parameters were recorded and blood samples were collected for 24 h. Plasma was separated and concentrations of pentoxifylline, its reduced metabolite I, and 6-keto-prostaglandin F_1α were determined. Heparinized whole blood was also incubated ex vivo with 1 ng Escherichi coli endotoxin/mL blood for 6 h before determination of plasma tumour necrosis factor activity. The peak plasma concentrations of pentoxifylline and metabolite I occurred at 15 min after bolus injection and were 9.2± 1.4 and 7.8± 4.3 μg/mL, respectively. The half-life of elimination ( t _½β) of pentoxifylline was 1.44 h and volume of distribution ( V d_area) was 0.94 L/kg. The mean plasma concentration of 6-keto-prostaglandin F_1α increased over time, with a significant increase occurring 30 min after the bolus administration. Ex vivo plasma endotoxin-induced tumour necrosis factor activity was significantly decreased at 1.5 and 3 h of infusion. These results indicate that infusion of pentoxifylline will increase 6-keto-prostaglandin F_1α and significantly suppress endotoxin-induced tumour necrosis factor activity in horses during the period of infusion.     

Pharmacokinetics and penetration of danofloxacin from the blood into the milk of cows

The single-dose disposition kinetics of danofloxacin were determined in clinically normal lactating cows after intravenous (i.v.) and intramuscular (i.m.) administration of the drug at 1.25 mg/kg. The drug concentrations in blood serum and milk were determined by microbiological assay methods and the data were subjected to kinetic analysis. The mean i.v. and i.m. elimination half-lives ( t _½el) in serum were 54.9 and 135.7 min, respectively. The steady-state volume of distribution ( V _ss) was 2.04 L/kg. The drug was quickly absorbed after i.m. injection but a 'flip flop' effect was clearly evident and bioavailability was > 100%. Penetration of danofloxacin from blood into milk was rapid and extensive with drug concentrations in milk exceeding those in serum beginning 90–120 min after i.v. and i.m. administration and onwards. Milk danofloxacin concentrations equal to or higher than the minimal inhibitory concentrations (MIC) for pathogenic Gram-negative bacteria and Mycoplasma species were maintained over ≈ 24 h.
  Concentrations greater than the MIC for Staphylococcus aureus were maintained in the milk for 12 h.     

Comparative Study of Proliferation and Apoptosis Characteristics of Different Virulence of Aleutian Mink Disease Virus in CRFK Cells

This study was aimed to compare the proliferation and apoptosis characteristics of different virulence of Aleutian mink disease virus(AMDV) in feline kidney cell (CPFK). CRFK cells were infected separately with the standard strain of AMDV-G and the wild strains of AMDV-DL124, AMDV-DL125, AMDV-QD2, AMDV-QD3 and AMDV-ZJ3. Indirect immunofluorescence,Real-time quantitative PCR and TCID₅₀ were used to detect the replication and expression of the viruses in the cells, at the same time the apoptosis induced by the viruses was detected. The results of IFA showed that CRFK cells which infected separately by wild strains appeared the fluorescence after 12 h of infection. With the extension of the infection time, the fluorescence of cells increased, but the fluorescence of AMDV-G was later than the wild strains, almost all of the cells were appeared the fluorescence after 72 h of infection. The Real-time quantitative PCR results showed that the tendency of genome replication of different virus were approximately the same. The genome replication began at 3 h after the AMDV-DL125 infection,the rapid increase of genome replication of AMDV-G occurred at 24 h after the infection, the genome replication of whole viruses reached a peak after 72 h of infection. The results of TCID₅₀ showed that the latent period of viruses infection were 0 to 12 h after infection, AMDV-G reached the peak after 60 h of infection. However, the wild strains at 48 to 72 h could maintain a higher infection titer and reached peak at 72 h after infection, then decreased with the cell disintegration. Apoptosis detection results which analysis by SPSS 23.0 statistical analysis software showed that, compared with control group,cell apoptosis was significantly higher after 2 to 12 h of cells infected by wild strains induced (P<0.05), cell apoptosis of AMDV-G was significantly lower than wild strains, however, the time of cell apoptosis induced by AMDV-G was longer,the apoptosis was still significant after 24 h of infection. But the apoptosis caused by virus infection was mostly concentrated in 2 to 12 h after infection. The results would provide some references for the study on the culture and identification and pathogenic mechanism of AMDV.     

不同毒力水貂阿留申病毒在猫肾细胞中的增殖特性及凋亡特性的比较研究

试验旨在对不同毒力水貂阿留申病毒（Aleutian mink disease virus,AMDV）在猫肾细胞（feline kidney cell,CRFK）中的增殖规律及其诱导细胞凋亡情况进行比较研究。将标准毒株AMDV-G及分离到的野毒株AMDV-DL124、AMDV-DL125、AMDV-QD2、AMDV-QD3、AMDV-ZJ3接种CRFK细胞,应用间接免疫荧光、实时荧光定量PCR、TCID₅₀测定技术研究病毒在细胞中的复制及表达情况,同时检测病毒诱导的细胞凋亡情况。间接免疫荧光结果显示,5株野毒株荧光着色趋势差异不大,均在感染后12 h出现荧光,随感染时间延长荧光增多,AMDV-G荧光出现时间比野毒株晚,但病毒感染后72 h几乎所有细胞均出现荧光;实时荧光定量PCR结果显示,基因组复制趋势大致相同,AMDV-DL125感染后3 h复制开始,AMDV-G感染后24 h复制才开始并呈快速增长趋势,但感染后72 h均达到峰值。TCID₅₀检测结果表明,0~12 h为病毒感染潜伏期,AMDV-G感染后60 h达到峰值,野毒株均在感染后72 h达到峰值,但是6株病毒均能在感染后48~72 h维持较高的感染滴度,其后随细胞崩解而降低。SPSS 23.0统计软件分析凋亡检测结果显示,与对照组相比,野毒株感染细胞后2~12 h诱导细胞凋亡差异显著（P<0.05）,AMDV-G诱导细胞凋亡差异明显低于野毒株,但是诱导细胞凋亡时间较野毒株长,在感染后24 h仍对细胞凋亡有较明显的诱导作用,但是各病毒诱导的细胞凋亡主要集中在2~12 h。该结果为AMDV的培养、鉴定及致病机理研究提供一定参考。