Pharmacokinetics of a controlled‐release liposome‐encapsulated hydromorphone administered to healthy dogs

The purpose of the study was to assess the pharmacokinetics of liposome‐encapsulated (DPPC‐C) hydromorphone administered intravenously (IV) or subcutaneously (SC) to dogs. A total of eight healthy Beagles aged 12.13 ± 1.2 months and weighing 11.72 ± 1.10 kg were used. Dogs randomly received liposome encapsulated hydromorphone, 0.5 mg/kg IV (n = 6), 1.0 mg/kg (n = 6), 2.0 mg/kg (n = 6), or 3.0 mg/kg (n = 7) SC with a 14–28 day washout between trials. Blood was sampled at serial intervals after drug administration. Serum hydromorphone concentrations were measured using liquid chromatography with mass spectrometry. Serum concentrations of hydromorphone decreased rapidly after IV administration of the DPPC‐C formulation (half‐life = 0.52 h, volume of distribution = 12.47 L/kg, serum clearance = 128.97 mL/min/kg). The half‐life of hydromorphone after SC administration of DPPC‐C formulation at 1.0, 2.0, and 3.0 mg/kg was 5.22, 31.48, and 24.05 h, respectively. The maximum serum concentration normalized for dose (C_MAX/D) ranged between 19.41–24.96 ng/mL occurring at 0.18–0.27 h. Serum hydromorphone concentrations fluctuated around 4.0 ng/mL from 6–72 h after 2.0 mg/kg and mean concentrations remained above 4 ng/mL for 96 h after 3.0 mg/kg DPPC‐C hydromorphone. Liposome‐encapsulated hydromorphone (DPPC‐C) administered SC to healthy dogs provided a sustained duration of serum hydromorphone concentrations.     

The effect of intravenous mannitol or oral glycerol on intraocular pressure in dogs

The effect of IV mannitol (1.5 gm/kg) or oral glycerol (1.4 and 2.0 gm/kg) on intraocular pressure (IOP) and serum osmolality (SOSM) was investigated in 24 normal dogs. Mean IOPs were significantly decreased from baseline values from 0.5 through 5.5 hours following mannitol administration with a mean maximum depression of 8.7 +/- 1.8 mm Hg whereas mean SOSM was significantly increased from baseline values. Mean IOPs were significantly decreased from baseline values from 1.0 through 10 hours following oral administration of 1.4 gm/kg glycerol with a mean maximal depression of 5.4 +/- 2.7 mm Hg. Mean SOSM increased initially followed by a significant decrease. The change in IOP following mannitol administration showed less variation (smaller standard deviations) than glycerol (1.4 gm/kg). Five of the 6 dogs that received the 2.0 gm/kg glycerol vomited; the mean IOP and SOSM values were not significantly altered from baseline values in these dogs. Four of 5 dogs given cooled (10C) 2.0 gm/kg glycerol vomited. The incidence of vomiting appeared to be dose related. Both mannitol and glycerol (1.4 gm/kg) are effective for decreasing IOP in normal dogs.     

Comparison of the cardio‐respiratory effects of methadone and morphine in conscious dogs††

The effects of methadone and morphine were compared in conscious dogs. Six animals received morphine sulfate (1 mg/kg) or methadone hydrochloride (0.5 mg/kg [MET0.5] or 1.0 mg/kg [MET1.0]) intravenously (i.v.) in a randomized complete block design. Cardiopulmonary variables were recorded before (baseline), and for 120 min after drug administration. One outlier was not included in the statistical analysis for hemodynamic data. Morphine decreased heart rate (HR) compared to baseline from 30 to 120 min (?15% to ?26%), while cardiac index (CI) was reduced only at 120 min (?19%). Greater and more prolonged reductions in HR (?32% to ?46%) and in CI (?24% to ?52%) were observed after MET1.0, while intermediate reductions were recorded after MET0.5 (?19 to ?28% for HR and ?17% to ?27% for CI). The systemic vascular resistance index (SVRI) was increased after methadone; MET1.0 produced higher SVRI values than MET0.5 (maximum increases: 57% and 165% for MET0.5 and MET1.0, respectively). Compared to morphine, oxygen partial pressure (PaO₂) was lower (?12% to ?13%) at 5 min of methadone (0.5 and 1.0 mg/kg), while carbon dioxide partial pressure (PaCO₂) did not change significantly. It was concluded that methadone induces cardiovascular changes that are dose‐related and is a more potent cardiovascular depressant agent than morphine in conscious dogs.     

Korean mistletoe enriched diet enhances innate immune response in kelp grouper, Epinephelus bruneus against Philasterides dicentrarchi

The present study investigated the immunostimulatory effect of Korean mistletoe Viscum album extract (KM-E) on innate immune response in kelp grouper Epinephelus bruneus against Philasterides dicentrarchi. Kelp grouper were divided into four groups of 25 each and fed with 0 (control), 0.5, 1.0, and 2.0% enriched diets with Korean mistletoe extract (KM-E). After feeding for 30 days, the fish were injected intraperitoneally (i.p.) with 100 μl of P. dicentrarchi (4.2 × 10(7)ciliates/ml) to study the immune responses at weeks 1, 2, and 4. The respiratory burst activity did not significantly enhance when fed with 0.5% and 1.0% supplementation diets on week 1 when compared to control diet. On weeks 2 and 4, the respiratory burst activity significantly increased with 1.0% and 2.0% diets. The phagocytic activity significantly enhanced with 1.0% and 2.0% diets, but not with 0.5% diet at any time. When fed with 1.0% KM-E-diet the lysozyme activity did not significantly vary at any week whereas with 1.0% and 2.0% diets it was significantly enhanced. The total protein level significantly increased with 1.0% and 2.0% KM-E-diets from weeks 1 to 4 as compared to control. The present study suggests that 1.0% or 2.0% KM-E-supplementation diet positively enhances the innate immune response in E. bruneus against P. dicentrarchi infection.     

Effect of low doses of cosyntropin on serum cortisol concentrations in clinically normal dogs

OBJECTIVE: To determine the lowest of 5 doses of cosyntropin (1.0, 0.5, 0.1, 0.05, or 0.01 microg/kg) administered IV that stimulates maximal cortisol secretion in clinically normal dogs. ANIMALS: 10 clinically normal dogs. PROCEDURES: 5 dose-response experiments were performed in each of the dogs. Each dog received 5 doses of cosyntropin (1.0, 0.5, 0.1, 0.05, and 0.01 microg/kg) IV in random order (2-week interval between each dose). Serum samples for determination of cortisol concentrations were obtained before (baseline) and at 10, 20, 30, 40, 50, 60, 120, and 240 minutes after cosyntropin administration. RESULTS: Compared with baseline values, mean serum cortisol concentration in the study dogs increased significantly after administration of each of the 5 cosyntropin doses. Mean peak serum cortisol concentration was significantly lower after administration of 0.01, 0.05, and 0.1 microg of cosyntropin/kg, compared with findings after administration of 0.5 and 1.0 microg of cosyntropin/kg. After administration of 0.5 and 1.0 microg of cosyntropin/kg, mean peak serum cortisol concentration did not differ significantly; higher doses of cosyntropin resulted in more sustained increases in serum cortisol concentration, and peak response developed after a longer interval. CONCLUSIONS AND CLINICAL RELEVANCE: Administration of cosyntropin IV at a dose of 0.5 microg/kg induced maximal cortisol secretion in healthy dogs. Serum cortisol concentration was reliably increased in all dogs after the administration of each of the 5 doses of cosyntropin. These data should be useful in subsequent studies to evaluate the hypothalamic-pituitary-adrenal axis in healthy and critically ill dogs.     

日粮中添加黄芪多糖对锦江黄牛瘤胃体外发酵及养分降解率的影响

[目的]试验旨在探究不同水平黄芪多糖(astragalus polysaccharides, APS)对锦江黄牛瘤胃体外发酵指标及养分降解率的影响。[方法]选取4头健康并安装永久瘤胃瘘管的锦江黄牛公牛,采集瘤胃液。采用单因素试验设计,试验分为6组,每组4个重复,在基础日粮中分别添加0、0.25%、0.5%、1.0%、2.0%和4.0%的黄芪多糖,体外发酵24 h后测定发酵参数、养分降解率,并评定多项指标综合指数(MFAEI)。[结果]结果表明,与对照组相比,1.0%和2.0%添加组的瘤胃液菌体蛋白(MCP)含量均显著升高(P<0.05);2.0%添加组的氨态氮(NH3-N)含量显著降低(P<0.05);1.0%添加组的丙酸含量显著升高(P<0.05),乙丙酸比值显著下降(P<0.05);0.5%、2.0%和4.0%添加组的粗蛋白(CP)降解率极显著高于对照组(P<0.01);各添加组的总产气量、pH、乙酸含量、干物质(DM)降解率、酸性洗涤纤维(ADF)降解率及中性洗涤纤维(NDF)降解率与对照组相比均无显著变化(P>0.05)。MFAEI指数评定结...     

Use of breath hydrogen testing to detect experimentally induced disaccharide malabsorption in healthy adult dogs.

OBJECTIVE: To develop a noninvasive method to detect disaccharide malabsorption in dogs by measuring hydrogen concentration ([H2]) in exhaled breath before and after experimentally induced disaccharide malabsorption. ANIMALS: 8 healthy mixed-breed dogs. PROCEDURE: [H2] was measured every 30 minutes for 8 hours after administration of disaccharide solutions (lactose, 0.5 g/kg of body weight; lactose, 1.0 g/kg; sucrose, 2.0 g/kg; maltose, 1.5 g/kg; and lactose [0.5 g/kg] and sucrose [2.0 g/kg]) to determine reference ranges of [H2] for each solution, which were compared with [H2] in dogs with experimentally induced disaccharide malabsorption. To induce disaccharide malabsorption, dogs were given a mild overdose of lactose (1.5 g/kg) or a disaccharidase inhibitor. In the latter experiment, acarbose (10 mg/kg, PO) was given with the combination of lactose (0.5 g/kg) and sucrose (2 g/kg), and with maltose (1.5 g/kg). RESULTS: Overdosing with lactose resulted in [H2] persistently outside the reference range for lactose in 5 of 8 dogs. Acarbose administration resulted in [H2] persistently outside the reference range in 7 of 8 dogs that received a combination of sucrose and lactose but did not consistently affect [H2] after administration of maltose. CONCLUSIONS: Disaccharide malabsorption resulted in [H2] outside the reference ranges in most of the adult dogs studied, suggesting that the technique may be useful in detecting naturally occurring disaccharidase deficiency.     

Effects of Halothane, Enflurane, and Isoflurane on Supraventricular and Ventricular Rate in Dogs With Complete Atrioventricular Block

Complete atrioventricular (AV) block was produced in 32 chloralose-anesthetized autonomically intact dogs to determine the effects of halothane, enflurane, and isoflurane on supraventricular and ventricular rate. Halothane (n = 17), enflurane (n = 6), and isoflurane (n = 9) were administered in three separate experiments in sequential minimum alveolar concentration (MAC) multiples of 0.5, 1.0, 1.5, 2.0, 1.5, and 1.0. Supraventricular rate, ventricular rate, and mean arterial blood pressure (MAP) were measured and recorded at baseline and after a 20-minute equilibration period of each inhalation anesthetic at each MAC multiple. Increasing concentrations of enflurane and isoflurane significantly decreased supraventricular rate ( P < .05). Ventricular rate was not significantly changed by sequential MAC multiples of halothane, enflurane, and isoflurane. Increasing concentrations of halothane, enflurane, and isoflurane significantly decreased MAP with enflurane producing the most significant decrease ( P < .05). Ventricular arrhythmias occurred in 5 of 17 dogs anesthetized with halothane and 1 of 9 dogs anesthetized with isoflurane. Inhalation anesthesia can significantly decrease supraventricular rate and MAP, does not alter ventricular rate, and can produce ventricular arrhythmias in dogs with complete AV block.     

A comparison of ketorolac with flunixin, butorphanol, and oxymorphone in controlling postoperative pain in dogs.

Ketorolac tromethamine, a nonsteroidal anti-inflammatory analgesic, was compared with flunixin and butorphanol for its analgesic efficacy and potential side effects after laparotomy or shoulder arthrotomy in dogs. Sixty-four dogs were randomly assigned to receive butorphanol 0.4 mg/kg body weight (BW) (n = 21), flunixin 1.0 mg/kg BW (n = 21), or ketorolac 0.5 mg/kg BW (n = 22), in a double blind fashion. The analgesic efficacy was rated from 1 to 4 (1 = inadequate, 4 = excellent) for each dog. The average scores after laparotomy were ketorolac, 3.4; flunixin, 2.7; and butorphanol, 1.6. After shoulder arthrotomy, the average scores were ketorolac, 3.5; flunixin, 3.0; and butorphanol, 1.4 (5/11 dogs). As butorphanol was unable to control pain after shoulder arthrotomy, oxymorphone, 0.05 mg/kg BW, replaced butorphanol in a subsequent group of dogs and had a score of 2.0 (6/11 dogs). Serum alanine aminotransferase and creatinine were significantly elevated above baseline at 24 hours postoperatively in dogs receiving flunixin. One dog in each group developed melena or hematochezia. One dog receiving ketorolac had histological evidence of gastric ulceration. We concluded that ketorolac is a good analgesic for postoperative pain in dogs.     

不同钴水平对北京鸭生产性能和血液生理生化指标的影响

试验选用11日龄北京鸭420只,研究日粮中添加不同水平的钴(0、0.25、0.5、1.0、2.0、4.0mg/kg)对北京鸭生产性能及相关血液生理生化指标的影响。结果表明:日粮中添加钴可显著提高北京鸭的血液红细胞数、红细胞压积(P<0.10),血浆总蛋白、白蛋白及球蛋白含量(P<0.01),红细胞C3b受体花环率(P<0.01)、血浆中维生素B1(2P<0.01)、钴含量(P<0.01)和肝脏钴含量(P<0.01),而且随日粮中钴添加量的增加,红细胞数、红细胞压积,血浆总蛋白、白蛋白、球蛋白含量,血浆维生素B12、钴和肝脏钴含量均呈二次曲线关系(P<0.01),而血浆铁含量线性降低(P<0.01),红细胞C3b受体花环率则线性提高(P<0.01)。因此,北京鸭日粮中钴的适宜添加量为1.8～2.8mg/kg。     

早杂籼稻糙米代替玉米日粮对肉鸡增重效果的研究

选择１日龄ＡＡ肉雏鸡４４０只,随机分为４组,每组１１０只。１组为玉米日粮组,２,３和４组依次以糙米取代日粮中玉米５０％,７０％和１００％。饲养４５ｄ,结果表明：１,２,３和４组鸡平均体重分别为１．９８０,２．０６７,２．２０６和２．３２５ｋｇ;日增重依次为４２．７,４４．７,４７．８和５０．４ｇ;与１组比较,２,３和４组鸡的日增重依次提高４．７％,１１．９％和１８．０％;料肉比依次下降０．５％,２．９％和７．１％;每千克增重耗料成本依次下降０．０４元,０．１３元和０．３１元。说明,随日粮中糙米代用量的增加,试验鸡增重加快,料肉比和增重成本下降。说明糙米作为肉鸡的能量饲料是可行的、有益的。     

Effect of sevoflurane concentration on visual evoked potentials with pattern stimulation in dogs

The purpose of this study was to investigate the effects of sevoflurane concentration on canine visual evoked potentials with pattern stimulation (P-VEPs). Six clinically normal laboratory-beagle dogs were used. The minimum alveolar concentration (MAC) of sevoflurane was detected from all subjects by tail clamp method. The refractive power of the right eyes of all subjects was corrected to −2 diopters after skiascopy. For P-VEP recording, the recording and reference electrode were positioned at inion and nasion, respectively, and the earth electrode was positioned on the inner surface. To grasp the state of CNS suppression objectively, the bispectral index (BIS) value was used. The stimulus pattern size and distance for VEP recording were constant, 50.3 arc-min and 50 cm, respectively. P-VEPs and BIS values were recorded under sevoflurane in oxygen inhalational anesthesia at 0.5, 1.0, 1.5, 2.0, 2.5 and 2.75 sevoflurane MAC. For analysis of P-VEP, the P100 implicit time and N75-P100 amplitude were estimated. P-VEPs were detected at 0.5 to 1.5 MAC in all dogs, and disappeared at 2.0 MAC in four dogs and at 2.5 and 2.75 MAC in one dog each. The BIS value decreased with increasing sevoflurane MAC, and burst suppression began to appear from 1.5 MAC. There was no significant change in P100 implicit time and N75-P100 amplitude with any concentration of sevoflurane. At concentrations around 1.5 MAC, which are used routinely to immobilize dogs, sevoflurane showed no effect on P-VEP.     

Effect of histone acetylation modification with sodium butyrate, a histone deacetylase inhibitor, on cell cycle, apoptosis, ploidy and gene expression in porcine fetal fibroblasts

The present study evaluated the effective dose of sodium butyrate (NaB), a histone deacetylase (HDAC) inhibitor, for determination of the level of enhancement of histone acetylation in porcine fetal fibroblasts (PFFs) based on their morphology, growth, apoptosis and cell cycle status. Cells were analyzed for their histone acetylation levels at H3, H4 and H2A and expression of genes related to histone deacetylation (HDAC1, HDAC2 and HDAC3), pro-apoptosis (Bax and Bak) and anti-apoptosis (Bcl-2). PFFs at passage 3-4 were cultured with 0, 0.5, 1.0, 2.0 and 3.0 mM NaB for 96 h. NaB inhibited cell proliferation at all tested concentrations in a dose-dependent manner. However, there was slow cell growth for PFFs treated with 2.0 and 3.0 mM NaB compared with those of untreated PFFs and those treated with other lower concentrations (0.5 and 1.0 mM). More than 85% of the cells that were untreated or treated with 0.5 or 1.0 mM NaB had intact membranes, whereas, approximately 30% of the cells treated with 2.0 or 3.0 mM NaB had increased cell sizes and a more flattened and elongated appearance. NaB induced apoptosis in a dose-dependent manner; the rates of apoptosis were 2.5 +/- 0.4% for 1.0 mM NaB, 7.6 +/- 1.1% for 2.0 mM NaB and 11.2 +/- 1.4% for 3.0 mM NaB. The chromosomal sets of PFFs treated with 0.5 and 1.0 mM NaB were normal, whereas a lower proportion of PFFs treated with 2.0 and 3.0 mM were classified as normal. NaB at 0.5 and 1.0 mM showed little effect on cell cycle. However, 2.0 and 3.0 mM resulted in an increased cell population at the G(0)/G(1) phase. Increased NaB concentrations led to elevated acetylation of H3, H4 and H2A. NaB altered the expression of histone deacetylation and apoptosis-related genes. In conclusion, 1.0 mM NaB induced histone hyperacetylation in the PFFs and produced less deleterious effects than other concentrations; these PFFs might serve as suitable donors for porcine somatic cell nuclear transfer (SCNT).     

Effects of Acute Hyperventilation on Serum Potassium in the Dog

The effects of increasing respiratory rates on arterial pH, PaCO2, HCO3, and potassium (K) were measured in normal anesthetized dogs. Hyperventilation resulted in increased pH, decreased PaCO2, decreased HCO3, and decreased K compared with those parameters in spontaneously breathing dogs. The changes were related quantitatively: each 10 mmHg decrease in PaCO2 was associated with a pH increase of 0.1, a HCO3 decrease of 2.0 mEq/L, and a K decrease of 0.4 mEq/L. There were no cardiac arrhythmias or clinical signs of hypokalemia. After termination of hyperventilation, serum K was slower to return to control values than PaCO2. The ratio of the duration of hyperventilation to the time required for return of serum K to control was 0.67.     

复方中草药对猪生长性能、屠宰性能、肉品质和免疫功能的影响

试验旨在研究复方中草药对猪生长性能、屠宰性能、肉品质和免疫功能的影响.将60头育肥猪随机分成4组,每组15头猪.对照组、Ⅰ组、Ⅱ组、Ⅲ组分别在基础日粮中添加0、0.5％、1.0％、2.0％的复方中草药.结果显示:与对照组相比,Ⅰ组育肥猪平均日增重、血清免疫球蛋白G(IgG)含量均显著提高(P＜0.05),失水率显著降低...     

虫源性壳聚糖对产蛋鸡生产性能及蛋品质的影响

试验采用单因子随机区组设计,选用31周龄尼克红商品代产蛋高峰鸡480只,随机分为5个处理,分别饲喂基础日粮及基础日粮中分别添加0.1%、0.5%、1.0%、2.0%虫源性壳聚糖的试验日粮,研究日粮添加壳聚糖对蛋鸡生产性能及蛋品质的影响。结果显示:饲料中添加1.0%的虫源性壳聚糖时,产蛋率比对照组提高了4.36%,蛋黄胆固醇含量比对照组降低了15.86%(P<0.05)。     

谷胱甘肽对犬精液冷冻保存效果的影响

为探讨在冷冻稀释液中添加谷胱甘肽（GSH）对犬精液冷冻保存效果的影响,采用按摩法采集5只杂种土犬的精液,离心去精清后,在冷冻液中分别加入0.5、1.0、1.5、2.0、2.5 mmol/L的GSH,制成0.25 mL的冻精进行冷冻保存,以不添加GSH的处理组作为对照组。解冻后在含有5% CO₂的空气、37 ℃、相对饱和湿度条件下孵育10 h,分别在孵育0、2、4、6、8、10 h时检查精子活力。结果显示：冻融后0 h,0.5、1.0 mmol/L GSH处理组的精子活力较高,分别为0.36和0.38,均显著（P<0.05）高于对照组和2.0、2.5 mmol/L处理组,且两者之间差异不显著（P>0.05）;1.0 mmol/L处理组的精子顶体完整率最高,为85.10%,显著（P<0.05）高于对照组,同时,其精子畸形率最低,为23.00%,显著（P<0.05）低于对照组。冻融后体外孵育2、4 h时,0.5、1.0 mmol/L处理组的精子活力均较高,其中,0.5 mmol/L处理组在体外孵育4 h时,其精子活力仍可达到0.30;孵育6 h时,1.0 mmol/L处理组精子活力最高,显著（P<0.05）高于对照组和2.0、2.5 mmol/L处理组;孵育8 h时,各GSH处理组的精子活力均显著（P<0.05）高于对照组;在孵育至10 h时,各GSH处理组的精子活力较其他孵育时间均有较大幅度的下降,未检测到对照组中有呈直线运动的精子。综上提示,在犬精液冷冻液中添加0.5~1.0 mmol/L的GSH能够显著提高冻融后的精子质量和体外存活时间。     

Effect of trichlorfon on hepatic lipid accumulation in crucian carp Carassius auratus gibelio

This study evaluated the toxic effects of the organophosphate pesticide trichlorfon on hepatic lipid accumulation in crucian carp Carassius auratus gibelio. Seventy-five fish were divided into five groups (each group in triplicate), and then exposed to 0, 0.5, 1.0, 2.0, and 4.0 mg/L of trichlorfon and fed with commercial feed for 30 d. At the end of the experiment, plasma and hepatic lipid metabolic biochemical status were analyzed. Triglyceride contents were significantly (P < 0.05) increased in liver but decreased in plasma after 1.0, 2.0, and 4.0 mg/L trichlorfon treatments. Plasma insulin contents were markedly (P < 0.05) increased when trichlorfon concentrations were 0.5, 1.0, and 4.0 mg/L. There were no significant differences in hepatic hormone-sensitive lipase contents between the trichlorfon-treated fish and the controls. Hepatic cyclic adenosine 3', 5'-monophosphate, very-low-density lipoprotein, and apolipoprotein B100 contents were decreased in the fish when trichlorfon concentration was 2.0 mg/L. Furthermore, electron microscope observations showed rough endoplasmic reticulum dilatation and mitochondrial vacuolization in hepatocytes with trichlorfon exposure. On the basis of morphological and physiological evidence, trichlorfon influenced crucian carp hepatic pathways of lipid metabolism and hepatocellular ultrastructure, which resulted in lipid accumulation in the liver.     

Evaluation of clomipramine as an adjunct to behavioural therapy in the treatment of separation-related problems in dogs

Forty-nine dogs showing signs of separation-related problems were randomly assigned to one of three groups: group A (15 dogs) received a placebo twice daily; group B (17 dogs) received clomipramine at 0.5 to 1.0 mg/kg twice daily; and group C (17 dogs) received clomipramine at 1.0 to 2.0 mg/kg twice daily. All the dogs also received behavioural therapy. Their owners were required to complete questionnaires about their dog's behaviour initially, and one, four and eight weeks after the treatment with clomipramine began. Bipolar ratings scales were used to monitor the frequencies of 'general', 'attachment-related' and 'separation-related' behaviours. Kruskal-Wallis tests and Kendall Rank correlations were used to determine any initial differences between the treatment groups, and the association between the initial scores and behavioural changes after one week of treatment with clomipramine. Extended Mantel-Haenszel statistics were used to evaluate the effects of clomipramine treatment versus the placebo, and Page's test was used to assess the effectiveness of behavioural therapy on its own. There were no significant differences in the demographic characteristics of the owners of the dogs assigned to the three groups. The dogs differed slightly in age between groups, and the dogs in the two clomipramine-treated groups were reported as showing problems at a significantly earlier age than those in the placebo group. Clomipramine treatment had a sustained suppressive effect on the dogs' general activity levels, and a more modest suppressive effect on their attachment-related tendency to want much physical contact with their owners. The typical signs of separation-related behaviour problems were not significantly affected by treatment with clomipramine, but behavioural therapy on its own was highly effective in reducing behavioural problems.     

Effects of medetomidine and xylazine on intraocular pressure and pupil size in healthy Beagle dogs

ObjectiveTo determine the effects of intramuscular (IM) administration of medetomidine and xylazine on intraocular pressure (IOP) and pupil size in normal dogs.Study designProspective, randomized, experimental, crossover trial.AnimalsFive healthy, purpose-bred Beagle dogs.MethodsEach dog was administered 11 IM injections of, respectively: physiological saline; medetomidine at doses of 5, 10, 20, 40 and 80 μg kg⁻¹, and xylazine at doses of 0.5, 1.0, 2.0, 4.0 and 8.0 mg kg⁻¹. Injections were administered at least 1 week apart. IOP and pupil size were measured at baseline (before treatment) and at 0.25, 0.50, 0.75, 1, 2, 3, 4, 5, 6, 7, 8 and 24 hours post-injection.ResultsA significant decrease in IOP was observed at 6 hours after 80 μg kg⁻¹ medetomidine compared with values at 0.25 and 0.50 hours, although there were no significant changes in IOP from baseline. In dogs treated with 8.0 mg kg⁻¹ xylazine, significant reductions in IOP were observed at 4 and 5 hours compared with that at 0.25 hours after administration. In dogs treated with 5, 10, 20 and 40 μg kg⁻¹ medetomidine and 0.5, 1.0 and 2.0 mg kg⁻¹ xylazine, there were no significant changes in IOP. Pupil size did not change significantly after any of the medetomidine or xylazine treatments compared with the baseline value.Conclusions and clinical relevanceLow or moderate doses of medetomidine or xylazine did not induce significant changes in IOP or pupil size. In contrast, high doses of medetomidine or xylazine induced significant changes up to 8 hours after treatment, but values remained within the normal canine physiological range. The results of this study suggest a lack of significant change in IOP and pupil size in healthy dogs administered low or moderate doses of xylazine or medetomidine.