鸡传染性法氏囊病与盲肠肝炎混合感染的诊治体会

2002年10月25日，商丘市睢县周某的鸡发生了以眼闭、垂翅、排淡黄色和白色相间稀便为特征的疾病，根据流行病学、剖检变化、实验室诊断为鸡的传染性法氏囊病(IBD)与盲肠肝炎混合感染。     

Efficacy of oral and intravenous dexamethasone in horses with recurrent airway obstruction

REASONS FOR PERFORMING STUDY: Although the efficacy of dexamethasone for the treatment of recurrent airway obstruction (RAO) has been documented, the speed of onset of effect and duration of action are unknown, as is the efficacy of orally administered dexamethasone with or without fasting. OBJECTIVES: To document the time of onset of effect and duration of action of a dexamethasone solution i.v. or orally with and without fasting. METHODS: Protocol 1 used 8 RAO-affected horses with airway obstruction in a crossover design experiment that compared the effect of i.v. saline and dexamethasone (0.1 mg/kg bwt) on pulmonary function over 4 h. Protocol 2 used 6 similar horses to compare, in a crossover design, the effects of dexamethasone i.v. (0.1 mg/kg bwt), dexamethasone per os (0.164 mg/kg bwt) with and without prior fasting, and dexamethasone per os (0.082 mg/kg) with fasting. RESULTS: Dexamethasone i.v. caused significant improvement in lung function within 2 h with a peak effect at 4-6 h. Dexamethasone per os was effective within 6 h with peak effect at 24 h at a dose of 0.164 mg/kg bwt prior to feeding. The duration of effect was, for all dexamethasone treatments, statistically significant for 30 h when compared to saline and tended to have a longer duration of effect when used orally. Dexamethasone per os at a dose of 0.164 mg/kg bwt to fed horses had mean effects comparable to dexamethasone at a dose of 0.082 mg/kg bwt per os given to fasted horses, indicating that feeding decreases bioavailability. CONCLUSIONS: Dexamethasone administered i.v. has a rapid onset of action in RAO-affected horses. Oral administration of a bioequivalent dose of the same solution to fasted horses is as effective as i.v. administration and tends to have longer duration of action. Fasting horses before oral administration of dexamethasone improves the efficacy of treatment. POTENTIAL RELEVANCE: Oral administration to fasted horses of a dexamethasone solution intended for i.v. use provides an effective treatment for RAO-affected animals.     

Evaluation of the efficacy of a commercial diet in the dissolution of feline struvite bladder uroliths

Clinical signs of struvite urolithiasis resolved in an average of 19 days in cats fed either a canned or dry urine-acidifying, magnesium-restricted diet, and stones completely dissolved in 31 of 39 cats in an average of 30 days. Stones were surgically removed from five cats, and analysis revealed that these stones were not composed of struvite. The results of this study strongly suggest that the diet will dissolve naturally occurring feline struvite bladder uroliths.     

Intravenous and intratracheal administration of trimetoquinol, a fast-acting short-lived bronchodilator in horses with 'heaves'

REASON FOR PERFORMING STUDY: Trimetoquinol (TMQ) is a potent beta-adrenoceptor agonist bronchodilator used in human medicine but has not been evaluated for potential use as a therapeutic agent for horses with 'heaves'. OBJECTIVES: To assess the pharmacodynamics of TMQ in horses with 'heaves' to determine potential therapeutic effects. METHODS: Increasing doses of TMQ were administered to horses with 'heaves' by i.v. and intratracheal (i.t.) routes. Doses ranged 0.001-0.2 microg/kg bwt i.v. and 0.01-2 microg/kg bwt i.t. Cardiac and airways effects were assessed by measurement of heart rate (HR) and maximal change in pleural pressure (deltaPplmax), respectively. Side effects of sweating, agitation and muscle trembling were scored subjectively. Duration of action to i.v. (0.2 microg/kg bwt) and i.t. (2 microg/kg bwt) TMQ was evaluated over 6 h. RESULTS: Intravenous TMQ was an exceptionally potent cardiac stimulant. Heart rate increased at 0.01 microg/kg bwt, and was still increasing after administration of highest dose, 0.2 microg/kg bwt. Airway bronchodilation, measured as a decrease in deltaPplmax, also commenced at 0.01 microg/kg bwt. By the i.t. route, TMQ was 50-100-fold less potent than by i.v. Side effects included sweating, agitation and muscle trembling. Overall, the onset of HR and bronchodilator effects was rapid, within about 3 min, but effects were over at 2 h. CONCLUSION: When administered i.v. and i.t., TMQ is a highly potent cardiac stimulant and a modest bronchodilator. It may not be an appropriate pharmacological agent by i.v. and i.t. routes for the alleviation of signs in horses with 'heaves'. Further studies of TMQ by oral and aerosol routes are necessary. POTENTIAL RELEVANCE: In horses, TMQ is a fast-acting bronchodilator with a short duration of action. It could be used as a rescue agent during an episode of 'heaves'. The i.v. and i.t. administration of TMQ is associated with side effects, similar to those reported for all other beta-agonists. However, other routes, such as aerosol and oral, may prove useful and safe for the alleviation of bronchoconstriction typical of 'heaves'.     

Response to nasopharyngeal oxygen administration in horses with lung disease

REASONS FOR PERFORMING STUDY: Guidelines for administration of oxygen to standing horses are unavailable because previous investigations of the efficacy of oxygen administration to increase arterial oxygenation in standing horses have produced equivocal results. OBJECTIVE: To determine the effect of nasal oxygen supplementation on inspired and arterial blood gas tensions in control horses and those with moderate to severe recurrent airway obstruction (RAO). METHODS: Normal horses (n = 6) and horses during an attack of RAO induced by stabling (n = 6) were studied. Oxygen was administered through either one or 2 cannulae, passed via the nares into the nasopharynx to the level of the medial canthus of each eye. Intratracheal inspired oxygen and carbon dioxide concentration and arterial blood gas tensions were measured at baseline and during delivery of 5, 10, 15, 20 and 30 l/min oxygen. RESULTS: Nasal cannulae and all but the highest oxygen flow rates were well tolerated. Fractional inspired oxygen concentration (F(I)O2) increased with flow but was significantly lower at all flow rates in horses with RAO compared with controls. Arterial oxygen tension (PaO2) was significantly increased (P < 0.001) by all flow rates, but was always lower in RAO-affected animals. At 30 l/min, PaO2 increased to 319 +/- 31 mmHg in control horses and 264 +/- 69 mmHg in horses with RAO. Additionally, a large arterial to end-tidal gradient for CO2 in RAO-affected horses was observed, indicating increased alveolar deadspace ventilation in these animals. CONCLUSIONS: The use of nasal cannulae to deliver oxygen effectively increases both F(I)O2 and PaO2 in horses with moderate to severe RAO. Oxygen flow rates up to 20 l/min are well tolerated, but flow rates of 30 l/min produce occasional coughing or gagging. POTENTIAL RELEVANCE: Oxygen therapy delivered by means of an intranasal cannula is a highly effective means of increasing arterial oxygen tension in horses with respiratory disease. Generally, flows of 10-20 l/min should be effective. If higher flows (20-30 l/min) are necessary, they should be delivered by means of 2 cannulae.     

A first estimate of the amino acid requirement for milk production of the high-producing female mink (Mustela vison)

Thirty mink dams nursing litters of six kits were assigned to one of three dietary treatments [high protein (HP), medium protein (MP) and low protein (LP)], fed ad libitum for 4 week from parturition, to investigate the effects of protein supply on milk yield and milk composition in order to estimate the amino acid requirement of the lactating mink. Twelve dams were held in an intensive care unit and subjected to balance experiments and the kits were injected with deuterium oxide to determine water kinetics and milk yield. Eighteen dams were kept under normal farm conditions but with feed intake of dams and live weight gain of kits being determined and milk samples collected. The ME intake was higher (p < 0.05) in dams fed the LP and MP diets than in dams fed the HP diet, whereas the amino acid intake (g/day) was lowest (p < 0.05) in dams fed the LP diet. In the third and fourth weeks of lactation milk yield was higher (p < 0.05) in dams fed the LP and MP diets than in dams fed the HP diet. Chemical composition of milk was not affected (p > 0.05) by dietary treatment. However, protein content tended (p = 0.06) to be lower in dams fed the LP diet. Amino acid content (g/16 g N) of milk was higher (p < 0.05) in dams fed the LP and MP diets than in dams fed the HP diet. This resulted in the highest (p < 0.05) amino acid intake and highest (p < 0.001) live weights of kits nursed by dams fed the LP and MP diets, which may be explained by a combined effect of higher ME intake and reduced energetic costs for glucose production through less amino acids being used in gluconeogenesis. In conclusion, the improved performance of dams fed the LP diet suggested that their requirement of essential amino acids and non-specific N were covered, and the requirement of digestible amino acids of lactating mink (kg(0.75)) was, thereby, estimated by use of a factorial approach including the amino acid excretion in milk of LP dams.     

Airway inflammation is associated with mucous cell metaplasia and increased intraepithelial stored mucosubstances in horses

This study was performed to determine if a peripheral sample of lung from the site where biopsy is conducted is representative of the rest of the lung and to investigate the relationship between airway inflammation and intraepithelial mucous production in the peripheral airways. Lung parenchyma samples were collected from five different regions of the lung in five control and five heaves-affected horses. Horse groups were defined by clinical response to stabling. Tissue sections were used for semi-quantitative scoring of lesions, to count the number of airways, to quantify the amount of stored mucosubstances (Vs) within the epithelium, and to count the number of epithelial cells in terminal airways. No significant differences were found between lung regions or between groups of horses. Lack of regional differences in airway structures means that a biopsy sample can be used for diagnosis and investigation of diffusely distributed diseases. Airway inflammation was correlated with mucous cell metaplasia and Vs. Therefore, in horses, mucus accumulation is partly caused by increased number of mucous cells and is associated with airway inflammation. Therapy targeted to reduce airway inflammation will help reduce the excessive mucous accumulation in horses.     

Asymmetric segregation of polarized antigen on B cell division shapes presentation capacity

During the activation of humoral immune responses, B cells acquire antigen for subsequent presentation to cognate T cells. Here we show that after mouse B cells accumulate antigen, it is maintained in a polarized distribution for extended periods in vivo. Using high-throughput imaging flow cytometry, we observed that this polarization is preserved during B cell division, promoting asymmetric antigen segregation among progeny. Antigen inheritance correlates with the ability of progeny to activate T cells: Daughter cells receiving larger antigen stores exhibit a prolonged capacity to present antigen, which renders them more effective in competing for T cell help. The generation of progeny with differential capacities for antigen presentation may have implications for somatic hypermutation and class switching during affinity maturation and as B cells commit to effector cell fates.