Temporary Bile Diversion in Cats with Experimental Extrahepatic Bile Duct Obstruction

The use of a cholecystostomy catheter for temporary bile diversion was investigated in four cats with experimentally induced extrahepatic bile duct obstruction. Eighteen days after ligation of the common bile duct, a 6.5 F accordion catheter was placed in the gallbladder with a 22 g Hawkins needle-guide system through a paracostal incision. Biochemical parameters and fasting serum bile acids were monitored for 16 days. There were significant decreases in mean total bilirubin, aspartate aminotransferase, and fasting serum bile acids within 72 hours of bile diversion, and in mean alanine aminotransferase within 96 hours. Attitude and appetite improved, and the catheter was tolerated well. Positive bile cultures developed in three cats. Histologic changes in the gallbladder included mucosal ulcerations, a mixed inflammatory cellular infiltration, and fibrosis of the submucosa.     

Open Intestinal Anastomosis with Surgical Stapling Equipment in 24 Dogs and Cats

Surgical stapling equipment was used to perform open antiperistaltic side-to-side ("functional end-to-end") entero-anastomoses in 20 dogs and 4 cats. Twenty-one anastomoses healed uneventfully. Seven animals with severe bacterial peritonitis required open peritoneal drainage and delayed abdominal closure. There was postoperative leakage at the anastomotic site in two dogs and a localized abscess at the staple line in one cat. No long-term complications occurred in follow-up periods of 3 to 29 months.     

Clinical observations on changes in concentrations of hormones in plasma of two stallions with thermally-induced testicular degeneration

To investigate effects of thermally-induced testicular degeneration on hormonal and seminal parameters in stallions, the scrotum was insulated for 36 hours in two mature (5-year-old mixed breed and 11-year-old Throughbred) stallions. Semen was collected daily for 10 days (DSO) prior to, and at intervals after, scrotal insulation. When DSO determinations were not being made, semen was collected 3 times weekly. Jugular blood samples were collected at 15-minute intervals for 6 hours from each stallion prior to, and at intervals after, scrotal insulation. A mouse interstitial cell testosterone assay was modified to quantify biologic activity of equine luteinizing hormone (BLH) in plasma samples. Immunoactive luteinizing hormone (ILH) and testosterone (T) concentrations were determined in plasma samples by routine RIA procedures. Percentages of progressively motile and morphologically normal spermatozoa began to decrease by 1 to 2 weeks postinsulation, reached nadir values at 3 to 3-1/2 weeks postinsulation, and returned to preinsulation values by 7 weeks postinsulation. Total number of spermatozoa and total number of progressively motile, morphologically normal spermatozoa in ejaculates at DSO returned to normal by 8 weeks postinsulation in stallion 2 and 12 weeks postinsulation in stallion 1. Concentrations of BLH and ILH increased, and while T concentrations decreased, immediately postinsulation. The increase in ILH concentrations was greater than the increase in BLH concentrations, resulting in a decrease in the BLH:ILH (B:I) ratio. Following the peak in LH secretion immediately postinsulation, LH concentrations gradually decreased while T concentrations increased. The B:I ratio was elevated from 1 to 13 weeks postinsulation compared to immediately postinsulation. In addition to changes in spermatozoal quality in ejaculates, stallion response to scrotal insulation included increased secretion of luteinizing hormone and impaired Leydig cell function (as determined by reduced testosterone concentration in circulating plasma). The proportion of biologically active LH secreted in response to thermal testicular injury increased during the recovery phase.     

Results of Partial Mandibulectomy for the Treatment of Oral Tumors in 142 Dogs

Partial mandibulectomy was performed for the treatment of benign or malignant oral tumors in 142 dogs. Forty-two dogs with a benign tumor (ameloblastoma) had a 22.5 month (range, 6 to 74 months) median disease-free interval, with a 97% 1-year survival rate; there was local recurrence in one dog. Twenty-four dogs with squamous cell carcinoma had a disease-free interval of 26 months (range, 6 to 84 months), with a 91% 1-year survival rate; recurrence and metastasis developed in two dogs and metastatic disease in one dog. Based on survival curves, 37 dogs with a melanoma had a median survival time of 9.9 months (range, 1 to 36 months), with a 21% 1-year survival rate; 20 dogs died or were euthanatized for recurrent or metastatic disease. Twenty dogs with osteosarcoma had a median survival time of 13.6 months (range, 3 to 28 months), with a 35% 1-year survival rate; nine dogs died or were euthanatized for recurrent or metastatic disease. Nineteen dogs with fibrosarcoma had median survival time of 10.6 months (range, 3 to 32 months), with a 50% 1-year survival rate; 12 dogs died or were euthanatized for recurrent or metastatic disease. Results of this and previous studies demonstrated that partial mandibulectomy was effective in prolonging survival and decreasing recurrence for squamous cell carcinoma and ameloblastoma. Progressive disease and corresponding low survival times were common in dogs with melanoma, osteosarcoma, and fibrosarcoma. There were no differences in survival times or the progression of disease among five partial hemimandibulectomy procedures. The high rates of recurrence and metastasis in dogs with these tumors suggest a need for evaluation of ancillary chemotherapy and local radiation therapy to decrease the prevalence of progressive disease.     

Effect of embryo age on the viability of equine embryos after cooled storage using two transport systems

The aim of this study was to compare the viability of 7- and 8-day-old equine embryos cooled and stored for 6 or 24 hours in two different transport systems. Embryos (n = 97) were recovered on day 7 or 8 and assigned to 10 groups (n = 10/group). Embryos within the same age group (D7 or D8) were evaluated immediately after collection (Group-0h) or after storage in an Equitainer at 5°C for 24 hours in 5 ml Emcare Holding Solution (EHS) (Group-E-24h) or 5 ml Ham's F10 (Group-H-24h) or in a refrigerator at 5°C in 500 ml Emcare Flushing Solution (EFS) for 6 hours (Group-B-6h) or 24 hours (Group-B-24h). After collection or storage, embryos were incubated in 1 μg/ml DAPI to determine the percentage of dead cells per embryo (DAPI positive, fluorescent cells). Subsequently, embryos were fixed in 4% paraformaldehyde and re-stained with DAPI to determine the total number of cells. The percentage of dead cells in group-0h and B-6h was similar and significantly lower than for embryos stored for 24 hours in groups B-24h, E-24h, and H-24h. The percentage of dead cells was similar for embryos stored in an Equitainer (groups E-24h and H-24h) and was significantly higher for embryos stored 24 hours in EFS (Group B-24h). Within each storage system (0h, B-6h, B-24h, E-24h, and H-24h) no significant difference in the percentage of dead cells was observed between 7- and 8-day-old embryos. Storage in 500 ml EFS at 5°C for 6 hours resulted in embryos of better quality than after the traditional 24-hour storage in an Equitainer, suggesting that this simplified system offers a good alternative for short-term storage and transport.     

Neuromuscular Effects of Doxacurium Chloride in Isoflurane-Anesthetized Dogs

Objective—To determine the neuromuscular effects of doxacurium chloride and to construct a dose-response curve for the drug in isoflurane-anesthetized dogs. Design—Randomized, controlled trial. Animals—Six healthy, adult, mixed-breed dogs (five female, one male) weighing 24.8 ° 2.8 kg. Methods—Anesthesia was induced with isoflurane in oxygen and maintained with 1.9% to 2.3% end-tidal isoflurane concentration. Paco₂ was maintained between 35 and 45 mm Hg with mechanical ventilation. Mechanomyography was used to quantitate the evoked twitch response of the paw after supramaximal train-of-four stimulation of the superficial peroneal nerve. After baseline values were recorded, the dogs received one of three doses of doxacurium (2.0, 3.5, 4.5 μg/kg of body weight) or a saline placebo intravenously in random order. All dogs received all treatments with at least 7 days between studies. After drug administration, the degree of maximal first twitch depression compared with baseline (T,%) was recorded. Dose-response relations of doxacurium were plotted in log dose-probit format and analyzed by linear regression to determine effective dose (ED₅₀ and ED₉₀) values for doxacurium. Results—The median log dose-probit response curve showed good data correlation (r= .999) with estimates of the ED₅₀ (2.1 μg/kg) and ED₉₀ (3.5 μg/kg) for doxacurium in isoflurane-anesthetized dogs. Mean ± SD values for T₁% (first twitch tension compared with baseline) at maximal depression after drug administration, onset (time from drug administration to maximal depression of T₁%), duration (time from maximal depression of T₁% to 25% recovery of T₁%), and recovery (time from 25% to 75% recovery of T₁%) times were 92%± 4%, 40 ± 5 minutes, 108 ± 31 minutes, and 42 ± 11 minutes for dogs treated with 3.5 μg/kg of doxacurium and 94%± 7%, 41 ± 8 minutes, 111 ± 33 minutes, and 37 ± 10 minutes for dogs treated with 4.5 μg/kg of doxacurium. Conclusion and Clinical Relevance—We conclude that doxacurium is a long-acting neuromuscular blocking agent with a slow onset of action. Doxacurium can be used to provide muscle relaxation for long surgical procedures in isoflurane-anesthetized dogs. Interpatient variability, particularly of duration of drug action, may exist in the neuromuscular response to the administration of doxacurium in dogs.     

A Comparison of Indirect Blood Pressure Monitoring Techniques in the Anesthetized Cat

Objective —To determine the accuracy of three indirect blood pressure monitoring techniques (oscillometric technique [OS], Doppler [DOP], and optical plethysmography [OP] [blood pressure determined with a pulse oximeter waveform]) when compared with direct arterial pressure measurement in cats. Study Design —Prospective study. Animal Population —Eight healthy (five female, three male), domestic short-hair cats, weighing 3.5 ± 0.8 kg Methods —Cats were anesthetized with isoflurane. The inspired concentration of isoflurane was adjusted to produce mild hypotension (80 to 100 mm Hg direct systolic), moderate hypotension (60 to 80 mm Hg direct systolic), and severe hypotension (<60 mm Hg direct systolic). Indirect pressure measurements were obtained from the thoracic limb and compared with concurrent direct measurement using regression analysis and a modification of Bland and Altman's technique. Results —All three techniques underestimated systolic pressure. OS produced the best prediction of systolic pressure with a bias ± precision of -15.9 ± 8.1 mm Hg. DOP and OP were relatively inaccurate with a bias ± precision of -25 ± 7.4 mm Hg and -25 ± 7.5 mm Hg. All three techniques correlated well with direct pressure with r values of 0.81, 0.88, and 0.88 for OS, DOP, and OP. DOP and OP provided an accurate prediction of direct mean arterial pressure with a bias ± precision of -0.8 ± 6 mm Hg and 0.6 ± 5.5 mm Hg. Correlation was good between DOP and mean arterial pressure with r = 0.89. Correlation was also good between OP and mean arterial pressure with r = 0.90. Conclusions —OS provided the most accurate prediction of direct systolic pressure. DOP and OP provided a good prediction of mean arterial pressure in the cat. Clinical Relevance —All three of these techniques are useful for detecting trends. Direct monitoring of blood pressure should be considered if accurate blood pressure measurement is required.     

Laparoscopic Cryptorchid Castration in Standing Horses

Objective — This article describes a new technique for laparoscopic cryptorchid castration in standing horses. Study Design — Prospective study. Animals or Sample Population — Eight horses aged 11 months to 3 years and weighing between 300 and 643 kg. Methods — Food was withheld for 24 to 36 hours, and then horses were sedated with detomidine HC1 (0.02 to 0.03 mg/kg) and butorphanol tartrate (0.02 mg/kg). The paralumbar fossa region was desensitized with 2% mepivacaine in an inverted “L” pattern and caudal epidural anesthesia was administered with either xylazine (0.18 mg/kg diluted to 10 to 15 mL with 0.9% sodium chloride) or a combination of 2% mepivacaine and xylazine (0.18 mg/kg). Initial laparoscopic exploration was performed from the left flank; in three horses, right flank laparoscopy was needed to complete the procedure. The spermatic cord was ligated within the abdomen with one or two sutures of 0 polydioxanone suture, and the testis or testes removed through a flank incision. Results — In five horses with no palpably descended testes, standing laparoscopy was the only procedure performed, whereas in two horses, the abdominal testis was removed laparoscopically, and the descended testis was removed under short acting anesthesia. In one horse, with nonpalpable testes, it was determined by laparoscopic observation that the testes were in the inguinal canal, and castration was performed under general anesthesia. No surgical or postoperative complications were noted. The right side of the abdomen, and especially the right vaginal ring, could be easily observed from the left side by passing the laparoscope through a small perforation in the mesocolon of the descending colon or by elevating the descending colon with an instrument or by use of an arm in the rectum. Conclusions — The standing laparoscopic approach combined with or without short-acting anesthesia to remove the descended testis is easily performed. Clinical Relevance — This approach will provide surgeons with another option to castrate cryptorchid stallions.     

Evaluation of Skin Bacterial Flora Before and After Aseptic Preparation of Clipped and Nonclipped Arthrocentesis Sites in Horses

Objective —This study evaluates skin bacterial flora before and after aseptic preparation of clipped and nonclipped arthrocentesis sites in horses. Study Design —The hair over one midcarpal joint and one distal interphalangeal joint on each horse was clipped. The contralateral joint served as the nonclipped comparison. Animals or Sample Population —Twelve adult horses. Methods —A prescrub sample for microbial culture was taken from the dorsal surface of all four joints for each horse. Each site was aseptically prepared with povidone iodine and 70% alcohol, followed by postscrub sampling for microbial culture. Colony forming units (CFUs) were determined for each sample, 24 hours after inoculation of blood agar plates. Results —There was no significant difference (P >.05) in number of postscrub CFUs between clipped and nonclipped skin over the midcarpal or distal interphalangeal joints. Percent bacterial reduction (mean ± SD%) after aseptic preparation differed significantly (P=.02) between clipped (99.8 ±.003%) and nonclipped (96.2 ±.05%) skin at the midcarpal joint, but not at the distal interphalangeal joint (clipped, 98.5 ±.03% and nonclipped, 97.8 ± 0.21%). There was a significant difference (P=.009) in number of prescrub CFUs obtained from clipped and nonclipped skin for the midcarpal joint. There was no significant difference in number of prescrub CFUs between clipped and nonclipped skin at the distal interphalangeal joint. Bacteria isolated from both clipped and nonclipped skin sampled postscrub included Bacillus sp, nonhemolytic Staphylococcus sp, and Micrococcus sp. Conclusions —The presence of hair over the midcarpal and distal interphalangeal joints does not appear to inhibit the ability of antiseptics to effectively reduce bacterial flora to an acceptable level for arthrocentesis. Clinical Relevance —Aseptic preparation of the skin over the midcarpal and distal interphalangeal joints can be accomplished without hair removal in horses.