COMPARISON OF TRANSCOLONIC 123I-IODOAMPHETAMINE AND PORTAL VEIN INJECTION OF 99mTc-MACROAGGREGATED ALBUMIN SHUNT FRACTION CALCU-LATIONS IN EXPERIMENTAL DOGS WITH ACQUIRED POR-TOSYSTEMIC SHUNTS

Shunt fraction was determined using transcolonic ¹²³I-iodoamphetamine (IMP) and portal vein injection of ^99mTc-macroaggregated albumin (MAA) in a group of eight dogs with chronic cirrhosis and acquired portosystemic shunts subsequent to total common bile duct ligation. Hepatic parenchymal damage was confirmed by alterations in liver function tests and liver histology. Seven of the eight dogs developed portal hypertension and had angiographic evidence of hepatofugal portal blood flow with multiple peripheral portosystemic anastomoses. Shunt fractions determined in the seven dogs with shunts varied from 39 to 100 using IMP and 45 to 93 using MAA. The remaining dog had normal portal pressure, a normal portal angiogram, and normal IMP and MAA scintigraphic studies. There was an excellent correlation between the two methods of shunt fraction calculation (R²= 0.98) and the line of regression was not significantly different from unity (IMP = 1.09 × MAA - 0.03).     

Effect of lidocaine on the minimum alveolar concentration of sevoflurane in dogs

Objective  To investigate the effects of a low-dose constant rate infusion (LCRI; 50 μg kg⁻¹ minute⁻¹) and high-dose CRI (HCRI; 200 μg kg⁻¹ minute⁻¹) lidocaine on arterial blood pressure and on the minimum alveolar concentration (MAC) of sevoflurane (Sevo), in dogs.
Study design  Prospective, randomized experimental design.
Animals  Eight healthy adult spayed female dogs, weighing 16.0 ± 2.1 kg.
Methods  Each dog was anesthetized with sevoflurane in oxygen and mechanically ventilated, on three separate occasions 7 days apart. Following a 40-minute equilibration period, a 0.1-mL kg⁻¹ saline loading dose or lidocaine (2 mg kg⁻¹ intravenously) was administered over 3 minutes, followed by saline CRI or lidocaine LCRI or HCRI. The sevoflurane MAC was determined using a tail clamp. Heart rate (HR), blood pressure and plasma concentration of lidocaine were measured. All values are expressed as mean ± SD.
Results  The MAC of Sevo was 2.30 ± 0.19%. The LCRI reduced MAC by 15% to 1.95 ± 0.23% and HCRI by 37% to 1.45 ± 0.21%. Diastolic and mean pressure increased with HCRI. Lidocaine plasma concentration was 0.84 ± 0.18 for LCRI and 1.89 ± 0.37 μg mL⁻¹ for HCRI. Seventy-five percent of HCRI dogs vomited during recovery.
Conclusion and clinical relevance  Lidocaine infusions dose dependently decreased the MAC of Sevo, did not induce clinically significant changes in HR or arterial blood pressure, but vomiting was common during recovery in HCRI.     

Hepatic Volume Measurements in Dogs with Extrahepatic Congenital Portosystemic Shunts before and after Surgical Attenuation

Background: In dogs with congenital portosystemic shunts (CPSS), the ability of the hypoplastic liver to grow is considered important for recovery after surgical shunt attenuation.
Objectives: This study investigated hepatic growth after extrahepatic shunt attenuation in dogs using magnetic resonance imaging (MRI) and computed tomography (CT).
Animals: Ten client-owned dogs with single extrahepatic CPSS.
Methods: Abdominal MRI, CT, or both were performed before and 8 days, 1, and 2 months after shunt attenuation. Liver volumes were calculated from the areas of the MRI or CT images.
Results: Before surgery, median liver volume was 18.2 cm³/kg body weight. Liver volume increased significantly after surgery. Growth was highest between days 0 and 8 and decreased afterward. Median liver volume was 28.8 cm³/kg at 2 months after attenuation. No significant differences in growth were found between dogs with complete or partial shunt closure or between dogs with complete or incomplete metabolic recovery. Volumes measured from consecutively performed MRI and CT images correlated well ( r = 0.980), but volumes from MRI images were significantly larger than volumes from CT images (6.8%; P = .008).
Conclusion and Clinical Importance: After shunt attenuation, rapid normalization of liver size was observed. Hepatic growth was not decreased in dogs after partial closure of CPSS or in dogs with subclinical, persistent shunting 2 months after surgery. CT is the preferred imaging method for volumetric estimation because of speed.     

A prospective study of basal insulin concentrations in dogs with congenital portosystemic shunts

Objectives : Hypoglycaemia is a common cause of morbidity in dogs with congenital portosystemic shunts but the aetiology is unknown. The hypothesis of this study was that dogs with congenital portosystemic shunts would have significantly higher insulin concentrations than dogs without congenital portosystemic shunts. The main objective of the study was to compare peripheral glucose and insulin concentrations between dogs with congenital portosystemic shunts and dogs without congenital portosystemic shunts. Methods : Peripheral serum insulin and plasma glucose concentrations were measured in dogs with congenital portosystemic shunts and without congenital portosystemic shunts and compared both between groups as well as to reference intervals derived from healthy dogs. Results : Congenital portosystemic shunts were diagnosed in 41 dogs. Forty‐eight dogs hospitalised with other conditions acted as controls. Serum insulin concentrations were mildly elevated (Ä40 μU/mL) in seven dogs and were markedly elevated in two dogs with congenital portosystemic shunts, yet mild hypoglycaemia (3·3 mmol/L) was detected in only one of these dogs. Four dogs with congenital portosystemic shunts showed fasting hypoglycaemia, yet insulin concentrations were within or below the reference interval in three. There was no difference between the median insulin concentration of dogs with congenital portosystemic shunts and without congenital portosystemic shunts. Clinical Significance : Hyperinsulinaemia is infrequently observed in dogs with congenital portosystemic shunts. The aetiology of hypoglycaemia in dogs with congenital portosystemic shunts merits further investigation.     

Pharmacokinetics of pradofloxacin and doxycycline in serum, saliva, and tear fluid of cats after oral administration

The pharmacokinetic properties of pradofloxacin and doxycycline were investigated in serum, saliva, and tear fluid of cats. In a crossover study design, six cats were treated orally with a single dose of pradofloxacin (Veraflox^® Oral Suspension 2.5%) and doxycycline (Ronaxan^® 100 mg) at 5 mg/kg body weight. Following administration, samples of serum, saliva, and tear fluid were taken in regular intervals over a period of 24 h and analysed by turbulent flow chromatography/tandem mass spectrometry. All values are given as mean ± SD. Pradofloxacin reached a mean maximum serum concentration ( C _max) of 1.1 ± 0.5 μg/mL after 1.8 ± 1.3 h ( t _max). In saliva and tear fluid, mean C _max was 6.3 ± 7.0 and 13.4 ± 20.9 μg/mL, respectively, and mean t _max was 0.5 ± 0 and 0.8 ± 0.3 h, respectively. Doxycycline reached a mean C _max in serum of 4.0 ± 0.8 μg/mL after 4.3 ± 3.2 h. Whilst only at two time-points doxycycline concentrations close to the limit of quantification were determined in tear fluid, no detectable levels were found in saliva. The high concentrations of pradofloxacin in saliva and tear fluid are promising to apply pradofloxacin for the treatment of conjunctivitis and upper respiratory tract infections in cats. As doxycycline is barely secreted into these fluids after oral application the mechanisms of its clinical efficacy remain unclear.     

Plasma and urine disposition and dose proportionality of ceftiofur and metabolites in dogs after subcutaneous administration of ceftiofur sodium

Nine male dogs (10.3–13.5 kg body weight) were randomly assigned to three groups of three dogs each and administered ceftiofur sodium subcutaneously as a single dose of 0.22, 2.2, or 4.4 mg ceftiofur free acid equivalents/kg body weight. Plasma and urine samples were collected serially for 72 h and assayed for ceftiofur and metabolites (derivatized to desfuroylceftiofur acetamide) using high-performance liquid chromatography. Urine concentrations remained above the MIC ₉₀ for Escherichia coll (4.0 μg/mL) and Proteus mirabilis (1.0 μg/mL) for over 24 h after doses of 2.2 mg/kg (8.1 μg/mL) and 4.4 mg/kg (29.6 μg/mL), the interval between treatments for ceftiofur sodium in dogs, whereas urine concentrations 24 h after dosing at 0.22 mg/kg (0.1 mg/Ib) were below the MIC ₉₀ for E.coli and P. mirabills (0.6 μg/mL). Plasma concentrations were dose-proportional, with peak concentrations of 1.66 ± 0.0990 μg/mL, 8.91 ± 6.42 μg/mL, and 26.7 ± 1.07 μg/mL after doses of 0.22, 2.2, and 4.4 mg/kg, respectively. The area under the plasma concentration versus time curve, when normalized to dose, was similar across all dosage groups.     

USE OF TRANSCOLONIC 123I-IODOAMPHETAMINE TO DIAGNOSE SPONTANEOUS PORTOSYSTEMIC SHUNTS IN 18 DOGS

Transcolonic ¹²³I-Iodoamphetamine is rapidly absorbed across the colonic mucosa and binds to amine receptors in the liver and lungs. During the first ten minutes following colonic administration, a simple ratio of lung counts to lung counts plus liver counts provides an accurate estimate of the fraction of portal blood that bypasses hepatic sinusoids in dogs with portosystemic shunts. Studies were performed on 24 dogs with suspect portosystemic shunt. Shunt fraction values for 18 dogs with surgically confirmed portosystemic shunt were obviously higher than published values for normal dogs, and also significantly higher than values for the other six dogs, later confirmed to lack shunts. Postoperative studies were repeated on ten dogs with single shunt vessels 1–2 days after shunt closure. Total shunt ligation resulted in normal postoperative shunt fraction, whereas partial shunt ligation resulted in persistant elevation of shunt fraction. Transcolonic iodoamphetamine scintigraphy is noninvasive, easy to perform, and provides an accurate method to diagnose dogs with portosystemic shunt.     

25-OH-D3 Concentrations in serum from healthy and paretic post parturient cows

The serum 25-OH-D₃, Ca, P, and Mg concentrations in thirty-seven cows that had calved in March April were studied in this trial. Twenty-three had puerperal paresis. Values observed in this group were Ca, 1.27 ± 0.3 mmol/l, P, 1.63 ± 0.82 mmol/l, Mg, 1.14 ± 0.27 mmol/l, and 25-OH-D₃, 32.7 ± 22 μg/l. In the fourteen age-matched healthy control cows from the same herd values were Ca, 1.93 ± 0.5 mmol/l, P, 3.09 ± 1.28 mmol/l, Mg, 1.01 ± 0.3 mmol/l and 25-OH-D₃, 31.5 ± 19.7 μg/l. The range of values for the cows serum 25-OH-D₃ concentration was l't; 3.2 to 76 μg/l. No differences could be established in terms of 25-OH-D₃ concentrations between the groups.     

Effects of metaraminol bitartrate on intraocular pressure in dogs under halothane anesthesia

The effects of metaraminol bitartrate on intraocular pressure (IOP) were studied in dogs anesthetized with halothane. Forty-five healthy, adult, mixed-breed dogs, of both sexes, were divided into three groups of 15 dogs each (GI, GII and GIII) and maintained under general anesthesia with halothane after tranquilization with levomepromazine and induction with thiopental. Saline (0.9%) was administered intravenously (IV) to GI through continuous infusion, at a velocity of 0.125 mL kg⁻¹ min⁻¹. GII and GIII received metaraminol 0.004% IV, at a dose of 5 μg kg⁻¹ min⁻¹, at 0.125 mL kg⁻¹ min⁻¹ and at a dose of 2 μg kg⁻¹ min⁻¹, at 0.06 mL kg⁻¹ min⁻¹, respectively. IOP was measured by applanation tonometry (Tono-Pen) before and during anesthesia. Results showed that IOP decreased in GI, increased in GII, and remained at basal levels in GIII. Continuous infusion of metaraminol at 2 μg kg min⁻¹ maintained IOP at pretest levels, while infusion at 5 μg kg⁻¹ min⁻¹ produced an elevation of IOP.     

Disposition of human drug preparations in the horse. III. Orally administered alclofenac

Concentrations of the non-steroidal anti-inflammatory drug (NSAID) alclofenac were determined by a sensitive high performance liquid chromatographic procedure in plasma and urine of horses following oral administration of a dose of 3 g. In plasma, alclofenac was present in detectable concentrations for 72 h. The plasma disposition in individual horses was best described by a bi-compartmental model with two successive rate constants ka₁= 0.05 ± 0.06 h^-1 and ka₂= 0.06 ± 0.01 h^-l. Alclofenac half-lives t _½ and t _1/2β were 1.0 ± 0.8 h and 6.9 ± 1.5 h, respectively. Maximal concentrations (38.9 ± 16.2 μg/ml) were obtained after 8.5 ± 2.4 h. Alclofenac was detected in urine for at least 48 h after dosing. The percentage of the dose excreted as unchanged alclofenac in 12 h was very low (0.68 ± 0.19%), total (free + conjugated) alclofenac accounted for 2.16 ± 0.55% of the dose.     

Congenital portosystemic shunts in Maltese and Australian Cattle Dogs

SUMMARY Congenital portosystemic shunts were definitively diagnosed in 62 dogs over a period of 15 years. Maltese and Australian Cattle Dogs were significantly over-represented, accounting for 14 and 13 cases, respectively. Maltese invariably had a single extrahepatic shunt derived from the left gastric or gastrosplenic vein, whereas Cattle Dogs usually had large intrahepatic shunts involving the right liver lobes. The clinical syndromes resulting from anomalous portosystemic communications were indistinguishable in the 2 breeds. Fasting blood ammonia concentration was elevated in 20 of 22 dogs tested, providing a minimally invasive and effective means of diagnosis. Complete or partial shunt attenuation was performed successfully in all 9 Maltese and in 2 of 6 Cattle Dogs in which it was attempted.     

Effect of breed on anatomy of portosystemic shunts resulting from congenital diseases in dogs and cats: a review of 242 cases

OBJECTIVE: To evaluate the effect of species and breed on the anatomy of portosystemic vascular anomalies in dogs and cats. DESIGN: Retrospective study of 233 dogs and nine cats presenting to the University Veterinary Centre, Sydney. METHODS: Case records were evaluated for breed, sex, age, anatomical and histological diagnosis. Cases were included when a portosystemic vascular anomaly resulted from a congenital or developmental abnormality of the liver or portal venous system. RESULTS: Disease conditions included single congenital portosystemic shunt with patent portal vasculature (214 dogs, nine cats), portal vein aplasia (nine dogs), multiple acquired shunts resulting from portal vein hypoplasia (seven dogs), biliary atresia (one dog) and microvascular dysplasia (one dog). One Maltese had a single, congenital shunt and multiple acquired shunts resulting from hepatic cirrhosis. Breeds that were significantly over-represented included the Maltese, Silky Terrier, Australian Cattle Dog, Bichon Frise, Shih Tzu, Miniature Schnauzer, Border Collie, Jack Russell Terrier, Irish Wolfhound and Himalayan cat. Bichon Frise with shunts were significantly more likely to be female than male (12:2, P < 0.001). Two hundred and fourteen dogs (91.4%), and all cats, had shunts that were amenable to attenuation. Inoperable shunts occurred in 19 dogs (8.2%). Fifty six of 61 (92%) operable shunts in large breed dogs were intrahepatic, versus 10/153 (7%) in small breeds (P < 0.0001). Breeds that were not predisposed to portosystemic shunts were significantly more likely to have unusual or inoperable shunts than dogs from predisposed breeds (29% versus 7.6%, P < 0.0001). No significant relationship between breed and shunt type could be determined in cats. CONCLUSION: Breed has a significant influence on shunt anatomy in dogs. Animals presenting with signs of portosystemic shunting may suffer from a wide range of operable or inoperable conditions. Veterinarians should be aware that unusual or inoperable shunts are much more likely to occur in breeds that are not predisposed to congenital portosystemic shunts.     

Investigation of pharmacokinetic parameters of tiamulin after intramuscular and subcutaneous administration in normal dogs

Laber, G. Investigation of pharmacokinetic parameters of tiamulin after intramuscular and subcutaneous administration in normal dogs. J. vet. Pharmacol. Therap. 11 , 45–49.
Kinetic variables for tiamulin in the normal dog have been determined. Serum concentrations of tiamulin were compared after intramuscular (i.m.) and subcutaneous (s.c.) administration of a single dose of tiamulin. Following a single i.m. dose of 10 mg/kg body weight, the compound was calculated to have a C_max= 0.61 ± 0.15 μg/ml, a T _max= 6 h and a t _½= 4.7 ± 1.4 h. Tiamulin showed dose-dependent pharmacokinetics when given as a single s.c. dose of either 10 mg or 25 mg/kg body weight. For the lower dose, the values C_max= 1.55 ± 0.11 μg/ml, T _max= 8 h and 1 _max= 4.28 ± 0.18 h were obtained. For the higher dose C _max= 3.14 ± 0.04 μg/ml, T _max= 8 h and t _½= 12.4 ± 3.4 h were calculated. When tiamulin was administered subcutaneously at a dose rate of 10 mg/kg body weight, higher and better maintained serum levels were achieved than those following i.m. administration. After repeated s.c. doses no significant accumulation of tiamulin occurred. Assuming that a continuous effective serum concentration is necessary throughout the course of therapy, these data would indicate that tiamulin should be given every 24 h.     

Canine congenital portosystemic encephalopathy

The case records of 21 dogs with congenital portosystemic encephalopathy are reviewed. The disorder was most common in Australian cattledogs (blue heelers; 8 cases), Old English sheepdogs (3 cases) and Maltese terriers (3 cases). Extra-hepatic shunts occurred in small breeds, with the exception of 1 cattledog, while intra-hepatic shunts occurred in the medium to large breeds. The most common clinical pathology abnormalities were abnormal ammonia tolerance, mild to moderate increases in plasma alanine aminotransferase or alkaline phosphatase concentrations, decreased total serum protein concentrations, increased fasting ammonia concentrations and ammonium biurate crystalluria. Radiological examination revealed that all the dogs had a small liver. The kidneys were enlarged in 5 of 10 dogs in which kidney size could be estimated. Surgical ligation of an extra-hepatic shunt was successful in 2 of 4 dogs in which it was attempted. Medical management resulted in alleviation of clinical signs in 5 of 8 dogs. The period of successful treatment ranged from a few months to over a year.     

Outcomes of cellophane banding for congenital portosystemic shunts in 106 dogs and 5 cats

OBJECTIVE : To report outcomes after cellophane banding of single congenital portosystemic shunts in dogs and cats. STUDY DESIGN : Retrospective study of sequential cases. ANIMALS : One hundred and six dogs and five cats. METHODS : Medical records were reviewed for breed, sex, age at surgery, shunt anatomy, results of pre- and postoperative biochemical analysis, development of postligation neurologic dysfunction, portal hypertension or other serious complications, and the owners' perception of their animal's response to surgery. RESULTS : Ninety-five dogs and all 5 cats had extrahepatic shunts. Eleven dogs had intrahepatic shunts. Six dogs (5.5%) died as a result of surgery from portal hypertension (2 dogs), postligation neurologic dysfunction (2), splenic hemorrhage (1) and suspected narcotic overdose (1). Serious complications were more common in dogs with intrahepatic shunts than those with extrahepatic shunts (P=.002). Postligation neurologic dysfunction necessitated treatment in 10 dogs and 1 cat; 8 dogs and the cat survived. Clinical signs attributed to portosystemic shunting resolved or were substantially attenuated in all survivors. Postoperative serum bile acid concentrations or results of ammonia tolerance testing were available for 88 animals; 74 (84%) were normal and 14 (16%) were abnormal. Multiple acquired shunts were documented in two animals. CONCLUSIONS : Cellophane banding is a safe and effective alternative to other methods of attenuation. CLINICAL RELEVANCE : Slow occlusion of portosystemic shunts using a variety of methods is being evaluated world wide. Cellophane banding is a relatively simple procedure with comparable safety and efficacy to previously reported techniques.     

Pharmacokinetics and tissue residues of norfloxacin and its N-desethyl- and oxo-metabolites in healthy pigs

The pharmacokinetic properties of norfloxacin were determined in healthy pigs after single intramuscular (i.m.) and intravenous (i.v.) dosage of 8 mg/kg body weight After i.m. and i.v. administration, the plasma concentration-time graph was characteristic of a two-compartment open model. After single i.m. administration, norfloxacin was absorbed rapidly, with a t _max of 1.46 ± 0.06 h. The elimination half-life ( t _1/2β) and the mean residence time of norfloxacin in plasma were 4.99 ± 0.28 and 6.05 ± 0.22 h, respectively, after i.m. administration and 3.65 ± 0.16 and 3.34 ± 0.16 h, respectively, after i.v. administration. Intramuscular bioavailability was found to be 53.7 ± 4.4%. Plasma concentrations greater than 0.2 μg/mL were achieved at 20 min and persisted up to 8 h post-administration. Maximal plasma concentration was 1.11 ± 0.03 μg/mL. Statistically significant differences between the two routes of administration were found for the half-lives of both distribution and elimination phases ( t _1/2α, t _1/2β) and apparent volume of distribution (V_d(area)). In pigs, norfloxacin was mainly converted to desethylenenorfloxacln and oxonorfloxacin. Considerable tissue concentrations of norfloxacin, desethylenenorfloxacin, and oxonorfloxacin were found when norfloxacin was administered intramuscularly (8 mg/kg on 4 consecutive days). The concentration of the parent fluoroquinolone in liver and kidney ranged between 0.015 and 0.017 μg/g on day 12 after the end of dosing.     

Retinol-Binding Protein in Serum and Urine of Hyperthyroid Cats before and after Treatment with Radioiodine

Background: Retinol-binding protein (RBP) is suggested as a clinically useful marker of renal function in cats.
Hypothesis: Serum and urinary RBP concentrations in hyperthyroid (HT) cats differ from those in healthy (H) cats; radioiodine (¹³¹I) treatment influences serum and urinary RBP concentrations in HT cats.
Animals: Ten HT and 8 H cats.
Methods: RBP concentration was evaluated in feline serum and urine samples from a prospective study.
Results: There was a significant ( P = .003) difference in the urinary RBP/creatinine (uRBP/c) ratios of H (−) and untreated HT (1.4 ± 1.5 × 10⁻² μg/mg) cats. Serum total thyroxine concentration (1.8 ± 1.9 μg/dL, 24 weeks) and uRBP/c (0.6 ± 1.0 × 10⁻² μg/mg, 24 weeks) decreased significantly ( P < .001) in HT cats at all time points after treatment with ¹³¹I, and these variables were significantly correlated with one another ( r = 0.42, P = .007). Serum RBP concentrations from HT cats (199 ± 86 μg/L) did not differ significantly ( P = .98) from those of H cats (174 ± 60) and did not change after treatment with ¹³¹I (182 ± 124 μg/L, P = .80).
Conclusion and Clinical Importance: The presence of urinary RBP in HT cats is a potential marker of tubular dysfunction that is correlated to thyroid status, although it is independent of circulating RBP concentrations. The decreased uRBP/c combined with the absence of changes in serum RBP after treatment suggests that the suspected tubular dysfunction was partly reversible with treatment of ¹³¹I.     

Prothrombotic and Inflammatory Effects of Intravenous Administration of Human Immunoglobulin G in Dogs

Background: Intravenous administration of human immunoglobulin G (hIVIgG) has been suggested to potentiate thromboembolism in dogs, but supportive scientific reports are lacking.
Objectives: To determine if hIVIgG therapy promotes hypercoagulability and inflammation in dogs.
Animals: Twelve healthy Beagle dogs.
Methods: Prospective, experimental trial. An hIVIgG/saline solution was infused IV at 1 g/kg BW over 8 hours to 6 dogs, and physiological saline was infused to the other 6 dogs. Blood samples were drawn before, during, and after infusion for serial measurement of indicators of coagulation and inflammation. Data were analyzed by 2-way repeated measures analysis of variance.
Results: Dogs administered hIVIgG developed mildly decreased blood platelet concentrations without thrombocytopenia (median, 200 × 10³/μL; range, 150–302 × 10³/μL; P < .01), leukopenia (median, 3.5 × 10³/μL; range, 20–62 × 10³/μL; P < .001), and mildly increased plasma total protein concentrations (median, 6.3 g/dL; range, 5.6–6.7 g/dL; P < .001). Administration of hIVIgG was also associated with increases in fibrin/fibrinogen degradation products in all dogs (either 5 μg/mL or 10 μg/dL), thrombin-antithrombin III complexes (median, 7.2 ng/mL; range, 4.9–14.2 ng/mL; P < .001), and C-reactive protein concentrations (median, 2.5 mg/dL; range, 0.5–4.3 mg/dL; P < .01).
Conclusion and Clinical Importance: Administration of hIVIgG to dogs promotes hypercoagulability and an inflammatory state. This should be further evaluated and considered when using hIVIgG in dogs with IMHA or other prothrombotic conditions.     

Pharmacokinetics of cefoperazone in horses

The pharmacokinetics and bioavailabilty of cefoperazone (CPZ) were studied following intravenous (IV) and intramuscular (IM) administration of single doses (30 mg/kg) to horses. Concentrations in serum, urine and synovial fluid samples were measured following IV administration. CPZ concentrations in serum, synovial fluid and spongy bone samples were measured following IM administration. After IV administration a rapid distribution phase ( t _1/2(α):4.22 ± 2.73 min) was followed by a slower elimination phase ( t 1/2(β) 0.77 ± 0.19 h). The apparent volume of distribution was 0.68 ± 0.10 L/kg. Mean synovial fluid peak concentration was 5.76 ± 0.74 μg/mL. After IM administration a bioavailability of 42.00±5.33% was obtained. Half-life of absorption was 2.51 ± 0.72 min and t _1/2(β) was 1.52±0.15 h. The mean synovial fluid and spongy bone peak concentrations at 2 h after IM administration were 2.91±0.85 μg/mL and 5.56±0.70 μg/mL, respectively.     

Use of transcolonic portal scintigraphy to evaluate efficacy of cellophane banding of congenital extrahepatic portosystemic shunts in 16 dogs

OBJECTIVE: To evaluate the efficacy of cellophane banding of single congenital extrahepatic portosystemic shunts in dogs using transcolonic portal scintigraphy. To investigate the portal circulation of those dogs with elevated postoperative shunt fractions to determine the cause of the persistent shunting. Further, to evaluate whether presenting signs, clinical pathology findings and liver histopathology are predictive of outcome. DESIGN: Prospective study of 16 dogs presenting with single congenital extrahepatic portosystemic shunts. PROCEDURE: Dogs with single extrahepatic portosystemic shunts attenuated by cellophane banding underwent portal scintigraphy and bile acids tolerance testing pre- and post-operatively. Dogs identified with elevated shunt fractions at 10 weeks post-operatively underwent mesenteric portovenography. Qualitative hepatic histopathology from all dogs was reviewed by a veterinary pathologist and assigned a semi-quantitative score to identify any abnormalities that may predict surgical outcome. RESULTS: At 10 weeks post cellophane banding, 10 of 16 cases (63%) had normal shunt fractions, whilst six dogs (37%) had increased shunt fractions and seven dogs (44%) had increased serum bile acids. Of these dogs, mesenteric portovenography revealed incomplete closure of the shunt in three dogs (18.6%) and multiple acquired shunts in three dogs (18.6%). Liver histopathology findings were similar for all dogs, regardless of outcome. CONCLUSIONS: Cellophane banding is an efficacious method for complete gradual occlusion of single extrahepatic shunts when the shunt vessel is attenuated to < or = 3 mm. Transcolonic portal scintigraphy is a reliable method for assessment of shunt attenuation and, unlike serum bile acids, is not influenced by other causes of liver dysfunction.