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Members of the Cool protein family contain SH3, Dbl, and pleckstrin homology domains and are binding partners for the p21-activated kinase (PAK). Using the yeast two-hybrid screen, we identified Cbl-b as a Cool family binding partner. We co-immunoprecipitated endogenous Cool and Cbl-b from a variety of breast cancer cell lines. The Cool-Cbl-b interaction requires the SH3 domain of Cool and competes with the binding of PAK to Cool proteins. Expression of Cbl-b effectively blocks the ability of Cool-2 to stimulate PAK, thus providing an additional mechanism, aside from catalyzing receptor ubiquitination, by which Cbl-b acts as a negative regulator for signaling activities requiring PAK activation.

Objective: To compare the incidence of behavior problems following tendonectomy or onychectomy in cats, as well as attitudes of owners following these procedures., Design: Nonrandomized clinical trial., Animals: 18 cats that underwent tendonectomy and 39 cats that underwent onychectomy., Procedure: Owners of cats that underwent tendonectomy or onychectomy between February 1993 and May 1998 were contacted by telephone and asked several questions regarding reasons for surgery as well as complications and behavioral changes in cats following surgery., Results: The most common reason for considering tendonectomy or onychectomy was to avoid damage caused by the cat scratching household materials. Avoidance of injury to humans or animals was chosen more often by owners whose cats underwent onychectomy than those that underwent tendonectomy. Tendonectomy was more likely to have been recommended by veterinarians than onychectomy. Significantly more cats that underwent tendonectomy (67%) than onychectomy (44%) returned to normal activity within 3 days after surgery. Significant differences were not detected regarding behavior problems after surgery., Conclusions and Clinical Relevance: Although tendonectomy and onychectomy involved some medical complications and behavior changes following surgery, owners had positive attitudes regarding both surgeries after the immediate postoperative period. Tendonectomy may be a humane alternative to onychectomy, although owners need to be advised that nail trimming is still necessary in cats after surgery.

Since the first description of feline hyperthyroidism in 1978, numerous treatment options for hyperthyroidism have been reported. Surgical removal of enlarged, autonomously functioning thyroid glands is one of the most commonly used treatment options. Affected cats must have a careful pre-operative evaluation to detect concurrent medical conditions such as renal disease or cardiomyopathy. Since more than 80% of hyperthyroid cats have neoplastic changes in both thyroid glands, bilateral thyroidectomy is necessary for treatment of the majority of hyperthyroid cats. Several different thyroidectomy techniques have been developed in an attempt to minimise potential post-operative complications associated with bilateral thyroidectomy such as hypocalcemia or recurrence of hyperthyroidism. Damage to or removal of all four parathyroid glands during bilateral thyroidectomy causes hypocalcemia, the most common post-operative complication. Recurrence of hyperthyroidism can occur months after initial thyroidectomy if residual adenomatous thyroid tissue is retained in the surgical site. The most effective surgical techniques for bilateral thyroidectomy involve preservation of at least one external parathyroid gland on the surface of the thyroid capsule. Additionally, the majority of the thyroid capsule must be removed to ensure that all neoplastic thyroid tissue is removed. The most recently described feline thyroidectomy techniques involve sequential removal of bilaterally affected thyroid glands. Staging a bilateral thyroidectomy allows time for ipsilateral parathyroid tissue to revascularise before the second thyroid gland is removed and the blood supply to the contralateral parathyroid glands is potentially interrupted. Thyroidectomy is a very effective treatment option for hyperthyroid cats. Surgical treatment of hyperthyroidism in cats offers permanent cure without chronic medical management. No specialised equipment other than standard surgical instrumentation and facilities are necessary. With practice, feline thyroidectomy can become a routine procedure in most veterinary hospitals., (Copyright 1999 W.B. Saunders Company Ltd.)

Lead dislodgement is one of the most common complications of endocardial pacing lead implantation in dogs. Incidence of lead displacement appears to be higher in large-breed, compared with small-breed, dogs, suggesting that excessive neck movements may be a contributing factor. To avoid introducing pacing leads through a vein in the neck, we developed a technique for implantation of endocardial pacing leads through the right costocervical vein. A right second intercostal space thoracotomy was performed to expose the vein, and the pacing generator was placed in the musculature over the lateral aspect of the thorax. The technique was performed in 6 dogs, 5 of which had had an endocardial pacing lead dislodge. None of the dogs had problems with lead dislodgement during follow-up periods of 15 to 20 months. Implantation of endocardial pacing leads through the costocervical vein should not be considered a replacement for implantation through the jugular vein. However, we believe that this technique is indicated for large dogs in which endocardial pacing leads implanted through the jugular vein have dislodged.

Objectives: To compare the dose-sparing effect of medetomidine on the propofol induction dose and concentration of halothane for maintenance of anesthesia during laparoscopy and to provide guidelines for effective and safe use of these anesthetics in dogs to ensure desirable perioperative analgesia., Animals: 14 purpose-bred dogs., Procedure: Cardiopulmonary and electroencephalographic responses were determined during 2 anesthesia protocols in dogs scheduled for laparoscopy. Fifteen minutes before anesthesia induction, all dogs received atropine sulfate (0.02 mg/kg of body weight, i.m.). Seven dogs were then given propofol (6.6 mg/kg, i.v.); anesthesia was maintained with halothane in oxygen. The other dogs were given medetomidine hydrochloride (10 micrograms/kg, i.m.) 5 minutes after administration of atropine sulfate; anesthesia was then induced by administration of propofol (2.8 mg/kg, i.v.) and was maintained with halothane in oxygen., Results: The halothane concentration required for laparoscopy was lower in dogs given medetomidine. Anesthetic requirements were significantly increased during abdominal manipulation in both groups. Total amplitude of the electroencephalograph in medetomidine-treated dogs was not significantly lower than that in dogs not given medetomidine. Pulmonary responses were stable throughout all procedures. The primary cardiovascular response was an increase in blood pressure associated with the medetomidine-atropine preanesthetic combination. Significant differences in total amplitude or frequency shifts (spectral edge) of brain wave activity were not associated with surgical stimulation., Conclusion: Lack of neurologic changes during laparoscopy supports the efficacy of either medetomidine-propofol-halothane or propofol-halothane combinations at higher concentrations to provide desirable analgesia and anesthesia in this group of dogs.

Five modifications of a cricoarytenoid lateralization and two modifications of a thyroarytenoid lateralization laryngoplasty technique were evaluated for their effect on rima glottidis area. All procedures and evaluations were performed on canine cadaver larynges. Cricoarytenoid lateralization (CAL) techniques provided a greater increase of the size of the glottic opening than did any of the thyroarytenoid lateralization techniques. Cricoarytenoid and interarytenoid disarticulation associated with CAL did not significantly increase glottic size compared with normal. After disarticulation of the cricoarytenoid joint, there was no difference in glottic enlargement whether the suture was placed through the muscular process or through the articular facet of the arytenoid cartilage. Transection of the sesamoid band combined with cricoarytenoid diarticulation distorted the dorsal margin of the rima glottidis.

The biochemical holding strength and histological characteristics of a laparoscopic stapled gastropexy (LG) adhesion were compared with that of an incisional gastropexy (IG) adhesion. An LG was performed in 14 dogs and an IG was performed in six dogs. During the LG procedure, the abdomen was insufflated with carbon dioxide and three cannulae were placed in the caudal aspect of the right side of the abdomen. A 35 mm laparoscopic stapler was used to staple the gastric antrum to the adjacent right lateral abdominal wall. The IG procedure was performed through ventral midline celiotomy. A 35 mm IG was made by apposing the gastric antrum to the adjacent right lateral abdominal wall with two continuous rows of suture. Half of each group of dogs was euthanatized at 7 and 30 days after surgery. The mean tensile load to failure at 7 days was 44.86 +/- 18.54 N for the LG group and 85.33 +/- 23.59 N for the IG group (P < .05). At 30 days the values were 72.39 +/- 18.01 N for the LG group and 71.17 +/-12.11 N for the IG group (P = .41). The gastropexy adhesions in the 7-day postoperative group contained variable amounts of fibrin, hemorrhage, mononuclear cell inflammation, loose fibrovascular tissue, and mature collagenous connective tissue. Adhesions in the 7-day postoperative group were divided subjectively into three histological subgroups based on the relative amounts of mature connective tissue within the adhesion. The LG and IG adhesions were randomly distributed among these subgroups (P = 1.0). Adhesions in the 30-day postoperative group contained well-organized fibrous connective tissue. No difference in the amount of connective tissue could be detected histologically in the LG or IG adhesions. Complications with the LG procedure included stomach perforation (2 cases), splenic puncture (2 cases), and subcutaneous emphysema (4 cases).

Two calves and two foals presented with episodic clinical signs of diffuse central nervous system disease. Portosystemic anomalies were tentatively diagnosed based on the history, clinical signs and increased serum concentrations of blood ammonia and total serum bile acids with normal concentrations of liver derived enzymes. one calf died before intraoperative contrast portography, whereas the other calf and both foals had marked clinical improvement after intensive medical therapy. Surgical correction was attempted in these three animals and was successful in one foal. A right paracostal celiotomy was superior to a ventral median approach for exposure to the portal vascular system and shunt access.

A colony of German shepherd dogs with inherited ventricular arrhythmias and sudden death had infertility that was resolved by intrauterine insemination. Mating of German shepherd males to related German shepherd females (40 cycles) by vaginal artificial insemination resulted in a low pregnancy rate of 35% and a small median litter size of 3.5. When these same German shepherd males were bred to female beagles by vaginal artificial insemination, the pregnancy rate of 100% (P = 0.02) and median litter size of 7.0 were significantly (P = 0.04) greater. Therefore, inadequate fertility existed when the German shepherds were mated. Because matings between these dogs were necessary, surgical intrauterine insemination of fresh semen was instituted in eight German shepherd females over nine cycles. In bypassing the cervix with this method, German shepherd fecundity increased significantly, with a pregnancy rate of 100% (P = 0.002) and median litter size of 8.0 (P = 0.001). Surgical intrauterine insemination may be an important method for management of canine infertility in the research environment.

Two months after initiation of chemotherapy, a totally implantable vascular access system was used for the continuing administration of chemotherapeutic agents to a ferret with multicentric lymphoma. The subcutaneously located injection port minimized the need for restraint and facilitated repeated IV administration of drugs. Treatment with a combination of L-asparaginase, vincristine sulfate, doxorubicin, cyclophosphamide, methotrexate, chlorambucil, and prednisone failed to induce complete remission. Survival time (interval from histologic diagnosis to euthanasia) was 10 months. The vascular access system remained patent and did not cause infection in the surrounding subcutaneous tissues during the 5-month period that it was in position.

The surgical treatment of thyroid cancer in the cat involves excision of one or both thyroid glands while sparing at least one parathyroid gland. The most common postoperative complication of bilateral thyroidectomy is transient hypocalcemia. Most feline thyroid tumors are benign, hyperfunctional thyroid adenomas. Surgical excision is usually curative. Canine thyroid cancer is most commonly malignant and nonfunctional. Successful surgical treatment of canine thyroid cancer depends on histologic and early diagnosis prior to metastasis or invasion of the cancer into adjacent structures within the neck.

Articular cartilage exposure and immediate postoperative stability provided by three medial surgical approaches in canine cadaver elbows were compared. The approaches evaluated were a desmotomy of the medial collateral ligament (DMCL) that included a tenotomy of the pronator teres muscle, a longitudinal myotomy of the flexor carpi radialis (MFCR), and an osteotomy of the medial epicondyle (OME). Nondestructive biomechanical testing was performed before the surgical approach and repeated after surgery. The stiffness at 13 degrees valgus deviation of the elbow and energy absorption up to 13 degrees valgus deviation of the elbow were determined from the preoperative and postoperative torque-rotation curves. The perimeters of the ulnar and humeral articular cartilage that were visualized through the approach were scored with a dental pick. Latex casts were made of articular surfaces of the elbow. The humeral and ulnar articular exposures were determined by computerized planimetric analysis of latex cast photocopies. The humeral cartilage exposure of the OME approach was significantly greater than either the MFCR or DMCL approaches. The DMCL approach provided a significantly greater humeral cartilage exposure than the MFCR approach. All three approaches provided statistically similar percentages of ulnar cartilage exposure. The stiffness and energy absorption of the OME and MFCR approaches were similar and significantly greater than the DMCL approach. The OME approach provided the best combination of exposure and immediate postoperative stability.

This study was divided into two phases. In the in vitro phase, a stainless steel bone plate was applied to the cranial surface of the radius in 14 canine limbs. The effect of the presence of a bone plate on bone density analysis using radiographic photodensitometry (RP) was evaluated by comparing the density measurement of the unplated limb to the density measurement of the plated limb. The optical density of the plated bones was 12% greater than that of the unplated bones. This information was used as a correction factor for the in vivo study. In the in vivo phase, 23 dogs with radial and ulnar fractures were examined for complications associated with the long-term application of a stainless steel plate applied to the cranial surface of the radius. In 14 dogs, RP analysis was used to compare the plated limb with the normal, contralateral limb. No significant differences in radial cortical bone density existed between the plated limb and the contralateral limb after taking into account the effect a bone plate had on photodensitometry readings. There was no significant correlation between the change in radial cortical density and the duration of bone plate application, suggesting that a steady state between bone loss and bone production occurs after long-term plate fixation of the fractured canine radius. The majority (87%) of the dogs with a plate applied to the radius greater than 1 year had normal limb usage when standing, walking, or running.

Studies were undertaken to determine the efficacy of milbemycin oxime against the enteric adult stages of Trichinella spiralis and of albendazole against the muscle stage larvae in experimentally infected dogs and cats. Specific-pathogen-free Beagle pups (n = 6) and domestic shorthair kittens (n = 6) were inoculated with 7,500 first-stage larvae of Trichinella spiralis. Physical examination (including collection of blood and fecal samples) was performed weekly. During the first week after inoculation, all animals had mild gastrointestinal tract disturbances, but stages of T spiralis were not observed in the feces. Beginning on postinoculation day (PID) 10, 3 pups and 3 kittens were treated with milbemycin oxime (1.25 mg/kg of body weight, PO, q 12 h) for 10 days. Muscle biopsy specimens were taken from dogs and cats on PID 26 and 29, respectively. Mean numbers of larvae per gram of muscle were 30.3 in the control and 37.7 in the treated dogs. Mean numbers of larvae per gram of muscle in the control and treated cats were 318.7 and 89.3, respectively. Two dogs and 2 cats were removed from the study at that time. The remaining animals, 2 each of the control and milbemycin oxime-treated animals, were given albendazole (50 mg/kg, PO, q 12 h) for 7 days starting at PID 31 and 34 in dogs and cats, respectively. Muscle biopsy specimens were again taken at PID 46 and 49, for dogs and cats, respectively; mean numbers of larvae recovered from muscle were 0.6 for dogs and 13.5 for cats.

Adrenocortical tumors were diagnosed in 5 adult spayed ferrets. Four ferrets had bilaterally symmetrical alopecia of the caudal femoral region, abdomen, and tail, and 1 had alopecia of the distal limbs and feet. All 5 ferrets had vulvar swelling. During abdominal ultrasonography, irregular masses, believed to involve the adrenal glands, were seen in all 5 ferrets. Unilateral adrenalectomy was performed successfully in each ferret by use of ventral midline celiotomy. On histologic examination of biopsy samples, 4 ferrets were found to have adrenocortical adenomas, and 1 ferret was found to have an adrenocortical adenocarcinoma. All clinical signs resolved after adrenalectomy, suggesting that the adrenocortical tumors had been secreting adrenocortical hormones.

Drainage with multiple Penrose drains is currently recommended as the primary treatment for canine prostatic abscesses. A recent report indicated that short term and long term urinary incontinence is a frequent complication associated with this technique. In this study, a modified multiple Penrose drain technique that avoids dissection dorsal to the prostate gland was performed in 17 dogs. Long term follow up information was obtained by telephone interview with the owners. Three dogs had urinary incontinence that resolved spontaneously within 3 days of surgery. Within the first year after that period, no other dogs developed incontinence. An excellent result was recorded in 12 dogs (71%) and a good result in 5 dogs (29%) having prostatic abscess drainage.

Cecal-colic volvulus was confirmed by surgery in two dogs. Both dogs were intact, male Great Danes. The clinical and diagnostic findings were not specific for large bowel volvulus. Clinical signs included peracute to acute onset of vomiting, mild abdominal distention and pain, lack of feces, and tenesmus. Abdominal radiographs demonstrated severe dilatation of bowel loops in both dogs. One dog survived.

We used lectins as probes to demonstrate the composition of membrane carbohydrates of canine keratinocytes in various functional stages and various degrees of differentiation. Keratinocytes during normal epidermal turnover were compared by lectin immunohistochemistry to cells of hyperplastic epidermis and neoplastic keratinocytes. Three types of epidermal tumors and oral squamous cell carcinomas were examined. In addition, two in vitro tissue culture systems for keratinocytes were studied and compared with in vivo epithelium. In normal skin, PNA reacted only weakly with basal cells, whereas in hyperplastic skin basal cells bound this lectin strongly, demonstrating increasing expression of PNA binding sites with increasing thickness of the stratified squamous epithelium. ConA bound to basal cell tumors only. In oral squamous cell carcinomas, the expression of distinct lectin binding sites correlated with certain histological growth patterns, e.g., UEA-I reacted with highly invasive tumors but not with tumors showing a solid growth pattern. Using cell surface iodination and polyacrylamide gel electrophoresis, distinct differences in cell membrane protein expression were demonstrated between normal and neoplastic keratinocytes. SDS-polyacrylamide gel electrophoresis of cultured normal and neoplastic keratinocytes revealed several cell surface proteins that are specific for either cell type. Neoplastic cells specifically express a 140 KD lectin binding cell surface glycoprotein. The results of this study show that lectin binding patterns of keratinocytes are dependent on the functional state and the degree of differentiation of the cells and demonstrate correlation of some histological growth patterns with distinct lectin binding phenotypes, suggesting association of expression of cell membrane carbohydrate moieties with growth patterns. In addition, close similarities between "lifted cultures" grown at the air-liquid interface and native tissue demonstrate the value of this culture system as a model for differentiated stratified squamous epithelium.

The ability of ectopic parathyroid tissue to support calcium homeostasis was evaluated by measuring serum concentrations of calcium, phosphorus, albumin, magnesium, and parathyroid hormone before and for 12 weeks after bilateral thyroparathyroidectomy in 14 cats. During the immediate postoperative period, significant decrease was observed in serum calcium, magnesium, and parathyroid hormone (PTH) concentrations. Serum PTH concentration remained subnormal and did not significantly increase during the 12-week observation period. Despite persistent hypoparathyroidism, serum calcium and magnesium concentrations gradually increased. Ectopic parathyroid tissue is not capable of maintaining normal serum calcium concentration immediately after thyroparathyroidectomy. Serum calcium concentration gradually normalizes after thyroparathyroidectomy, apparently by means of a PTH-independent mechanism.

Neoplastic canine keratinocytes derived from a spontaneous oral squamous cell carcinoma were maintained in culture for more than 45 passages. The presence of desmosomes and keratin filaments was demonstrated by electron microscopy and immunohistochemistry. The keratinocytes were grown in two different culture conditions to induce variations in the stage of differentiation, i.e., in submerged cultures and at the air-liquid interface. For comparison, normal canine keratinocytes were grown under the same conditions. Anisocytosis was present in neoplastic cultures grown submerged in medium. Grown at the air-liquid interface, neoplastic keratinocytes differentiated into a well-organized, multilayered stratified squamous epithelium analogous to normal keratinocytes. Rare areas of irregular growth and formation of whorls were detected. Expression of lectin binding sites and specific cell surface antigens of neoplastic and normal keratinocytes demonstrated marked similarities between the two cell lines. Neoplastic cells lacked certain surface antigens that are present on normal cells. Squamous cell carcinoma cells grew faster than normal canine keratinocytes as demonstrated by growth curve evaluation. Neoplastic keratinocytes responded to growth stimulation by epidermal growth factor and cholera toxin as do normal keratinocytes. Neoplastic cells grown in medium lacking these factors proliferated faster than growth factor stimulated normal keratinocytes.

A radioimmunoassay for measurement of midmolecule parathyroid hormone (PTH) concentration in serum from dogs was validated for use on serum from cats. The assay detected an increase in serum concentration of PTH after IV infusion of Na2 EDTA in healthy cats. Infusion of calcium chloride caused a decrease in measured PTH. Accuracy of the assay was demonstrated by quantitative recovery of a feline parathyroid gland extract added to pooled feline sera. Mean interassay and intra-assay coefficients of variation were 0.13 and 0.07, respectively. Sensitivity of the assay was 0.1 ng of PTH/ml. The median PTH concentration measured in 40 adult cats was 3.5 ng/ml, with a range of 1.16 to 11.0 ng/ml.

Diabetes is a prevalent chronic disease that traditionally requires severe reliance on medication for treatment. Oral medication and exogenous insulin can only temporarily maintain blood glucose levels and do not cure the disease. Most patients need life-long injections of exogenous insulin. In recent years, advances in islet transplantation have significantly advanced the treatment of diabetes, allowing patients to discontinue exogenous insulin and avoid complications.Long-term follow-up results from recent reports on islet transplantation suggest that they provide significant therapeutic benefit although patients still require immunotherapy, suggesting the importance of future transplantation strategies. Although organ shortage remains the primary obstacle for the development of islet transplantation, new sources of islet cells, such as stem cells and porcine islet cells, have been proposed, and are gradually being incorporated into clinical research. Further research on new transplantation sites, such as the subcutaneous space and mesenteric fat, may eventually replace the traditional portal vein intra-islet cell infusion. Additionally, the immunological rejection reaction in islet transplantation will be resolved through the combined application of immunosuppressant agents, islet encapsulation technology, and the most promising mesenchymal stem cells/ regulatory T cell and islet cell combined transplantation cell therapy. This review summarizes the progress achieved in islet transplantation, and discusses the research progress and potential solutions to the challenges faced. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to develop a biocompatible oximetric electron paramagnetic resonance (EPR) spin probe with reduced self-relaxation, and sensitivity to oxygen for a higher signal-to-noise ratio and longer relaxation times at high oxygen concentration, compared to the reference spin probe OX071. Procedures: SOX71 was synthesized by succinylation of the twelve alcohol groups of OX071 spin probe and characterized by EPR at X-Band (9.5 GHz) and at low field (720 MHz). The biocompatibility of SOX71 was tested in vitro and in vivo in mice. A pharmacokinetic study was performed to determine the best time frame for EPR imaging. Finally, a proof-of-concept EPR oxygen imaging was performed on a mouse model of a fibrosarcoma tumor. Results: SOX71 was synthesized in one step from OX071. SOX71 exhibits a narrow line EPR spectrum with a peak-to-peak linewidth of 66 mG, similar to OX071. SOX71 does not bind to albumin nor show cell toxicity for the concentrations tested up to 5 mM. No toxicity was observed after systemic delivery via intraperitoneal injection in mice at twice the dose required for EPR imaging. After the injection, the probe is readily absorbed into the bloodstream, with a peak blood concentration half an hour, post-injection. Then, the probe is quickly cleared by the kidney with a half-life of ~ 45 min. SOX71 shows long relaxation times under anoxic condition (T1e = 9.5 µs and T2e = 5.1 µs; [SOX71] = 1 mM in PBS at 37 °C, pO2 = 0 mmHg, 720 MHz). Both the relaxation rates R1e and R2e show a decreased sensitivity to pO2, leading to twice longer relaxation times under room air conditions (pO2 = 159 mmHg) compared to OX071. This is ideal for oxygen imaging in samples with a wide range of pO2. Both the relaxation rates R1e and R2e show a decreased sensitivity to self-relaxation compared to OX071, with a negligible effect of the probe concentration on R1e. SOX71 was successfully applied to image oxygen in a tumor. Conclusion: SOX71, a succinylated derivative of OX071 was synthesized, characterized, and applied for in vivo EPR tumor oxygen imaging. SOX71 is highly biocompatible, and shows decreased sensitivity to oxygen and self-relaxation. This first report suggests that SOX71 is superior to OX071 for absolute oxygen mapping under a broad range of pO2 values. [ABSTRACT FROM AUTHOR]

Purpose: Spatial heterogeneity in tumor hypoxia is one of the most important factors regulating tumor growth, development, aggressiveness, metastasis, and affecting treatment outcome. Most solid tumors are known to have hypoxia or low oxygen levels (pO2 ≤10 torr). Electron paramagnetic resonance oxygen imaging (EPROI) is an emerging oxygen mapping technology. EPROI utilizes the linear relationship between the relaxation rates of the injectable OX071 trityl spin probe and the partial oxygen pressure (pO2). However, most of the EPROI studies have been limited to mouse models of solid tumors because of the instrument-size limitations. The purpose of this work was to develop a human-sized 9-mT (250 MHz resonance frequency, 60 cm bore size) pulse EPROI instrument and evaluate its performance with rabbit VX-2 tumor oxygen imaging. Methods: A New Zealand white rabbit with a 3.2-cm VX-2 tumor in the calf muscle was imaged using the human-sized EPROI instrument and a 2.25-in. ID volume coil. The animal received a ~8-min intravenous injection of OX071 (5.2 mL total volume at 72 mM concentration) and, after 75 min, an intratumoral injection (120 μL total at 5 mM OX071 concentration) and underwent EPROI. At the end of the experiments, MRI was performed using a preclinical 9.4-T MRI system to outline the tumor boundaries. Results: For the first time, a human-sized pulse EPROI instrument with a 60-cm bore size/250-MHz frequency was built and evaluated using rabbit tumor oxygen imaging. For the first time, the systemic IV injection of the oxygen-sensitive trityl OX071 spin probe was used for an animal of this size. The resulting EPROI image from the IV injection showed complete tumor coverage. The image obtained after intratumoral injection showed localized coverage in the upper lobe of the tumor, demonstrating the need for improved intratumoral injection protocol. Conclusions: This study demonstrates the performance of the world's first human-sized pulse EPROI instrument. It also demonstrates that the EPROI of larger animals can be performed using the systemic injection of a manageable amount of the spin probe. This brings EPROI one step closer to clinical applications in cancer therapies. Oxygen imaging is a platform technology, and the instrument and techniques developed here will also be useful for other clinical applications. [ABSTRACT FROM AUTHOR]

The primary objective of this study was to compare time efficiency and complication rates between smooth monofilament suture (SMS) and barbed suture (BS) using the three-layer continuous incisional closure pattern after ovariohysterectomy in a high-quality high-volume spay/neuter clinic. The study was designed as a randomized controlled trial enrolling 71 adult female dogs. Dogs were randomly assigned to SMS or BS treatments. The effect of closure with BS or SMS on closure time was tested through multilevel, multivariable linear regression in a generalized linear mixed model. Body condition score, weight, and pre-closure incision length were tested as covariates. Surgeon was included in the model as a random effect. Preclosure incision length (p = 0.01) and method (p = 0.0001) were associated with closure time. Adjusting for pre-closure incision length, the average time for closure with SMS was 6.5 min (range 3.70-10.31 min), and the average time for closure with BS was 4.91 min (range 3.05-8.05 min). Accounting for the closure method, the closure time increased by 39 s for each additional centimeter of incision length. BS was more efficient than SMS when performing the three-layer continuous suture pattern. No short-term telemedicineassessed complications were noted with either treatment method. BS can improve efficiency in surgical closures, especially considering large volumes of animals, and appears to have a similar short-term, telemedicine-assessed complication rate when compared to SMS. [ABSTRACT FROM AUTHOR]

We performed a retrospective study of 15 cases of extrahepatic biliary tract rupture in dogs. Nine of the 15 dogs had ductal rupture associated with blunt abdominal trauma. The remaining 6 dogs had gallbladder rupture associated with cholelithiasis and/or cholecystitis. The relationship between site of rupture and cause of rupture was significant (p = 0.0002). A review of 60 dogs with extrahepatic biliary tract rupture reported in the veterinary literature revealed a similar relationship (p = 0.0001). Thirty-two of 33 cases of ductal rupture were associated with blunt abdominal trauma and 25 of 27 cases of gallbladder rupture were associated with cholelithiasis and/or cholecystitis. Totals after combining our cases with those from the literature suggests the most frequent area of ductal rupture is the common bile duct distal to the last hepatic duct, followed by the junction of the common bile duct with the duodenum.

Pancreatic β cells differentiated from stem cells provide promise for cell replacement therapy of diabetes. Human pluripotent stem cells could be differentiated into definitive endoderm, followed by pancreatic progenitors, and then subjected to endocrinal differentiation and maturation in a stepwise fashion. Many achievements have been made in making pancreatic β cells from human pluripotent stem cells in last two decades, and a couple of phase I/II clinical trials have just been initiated. Here, we overview the major progresses in differentiating pancreatic β cells from human pluripotent stem cells with the focus on recent technical advances in each differentiation stage, and briefly discuss the current limitations as well., (© 2022. The Author(s).)

Purpose: Type 1 diabetes (T1D) is an autoimmune disease that leads to the loss of insulin-producing pancreatic beta cells. Beta cell replacement devices or bioartificial pancreas (BAP) have shown promise in curing T1D and providing long-term insulin independence without the need for immunosuppressants. Hypoxia in BAP devices damages cells and imposes limitations on device dimensions. Noninvasive in vivo oxygen imaging assessment of implanted BAP devices will provide the necessary feedback and improve the chances of success. Pulse-mode electron paramagnetic resonance (EPR) oxygen imaging (EPROI) using injectable trityl OX071 as the oxygen-sensitive agent is an excellent technique for obtaining partial oxygen pressure (pO 2 ) maps in vitro and in vivo. In this study, our goal was to optimize in vivo mouse abdominal EPROI and demonstrate proof-of-concept pO 2 imaging of subcutaneously implanted BAP devices., Methods: All EPROI experiments were performed using a 25 mT EPROI instrument, JIVA-25®. For in vivo EPROI experiments, trityl OX071, a whole-body mouse resonator (∅32 mm × 35 mm), C57BL6 mice, and the inversion recovery electron spin echo (IRESE) pulse sequence were utilized. We investigated the signal amplitude and pO 2 in mouse abdomen region for intravenous (i.v.) and intraperitoneal (i.p.) injection methods with either only a single bolus (B) or bolus plus infusion (BI) for 72.2 mM OX071 and the effect of OX071 concentrations from 18 to 72.2 mM for the i.p.-B injection method. We also investigated the impact of animal respiratory rate on mouse abdominal pO 2 . Finally, we performed proof-of-concept pO 2 imaging of two subcutaneously implanted BAP devices, OxySite and TheraCyte. At the end of the four-week study, the TheraCyte devices were extracted and analyzed for fibrosis, vascular differentiation, and immune cell infiltration., Results: We established that mouse abdominal pO 2 remains stable irrespective of trityl injection methods, concentrations, imaging time, or animal breathing rate. We demonstrate that the i.p.-B and i.p.-BI methods are suitable for EPROI, and i.p.-B method provides higher signal amplitude compared to i.v.-BI and up to 75 min of imaging. An injection with a reduced trityl concentration and higher volume provides higher signal amplitude for i.p.-B method at the beginning. We also highlight the advantage of milder anesthesia for consistent, reliable mouse pO 2 imaging. Finally, we demonstrate that EPROI could provide longitudinal noninvasive oxygen assessment of subcutaneously implanted BAP devices in vivo., Conclusions: In vivo EPROI is a reliable technique for mouse abdominal oxygen imaging and longitudinal assessment of subcutaneously implanted BAP devices noninvasively. This work reports abdominal oxygen imaging in the mouse model and demonstrates its application for the assessment of BAP devices. Even though the application focus of this work was on cell therapy, the techniques developed will have a much broader use in the biomedical field., Competing Interests: Declarations. Conflict of Interest: MK and BE report ownership in O2M Technologies, LLC. All other authors have no conflict., (© 2024. The Author(s), under exclusive licence to World Molecular Imaging Society.)

Objective: To describe sacroiliac luxation stabilization in cats using two screws and to report clinical and radiographic short-term outcomes., Study Design: Retrospective clinical cohort study., Sample Population: Cats (n = 67) with sacroiliac luxation., Methods: Case records of cats presented for sacroiliac luxation stabilized using two screws per side affected, one lag and one positional, between 2014 and 2023 were reviewed. The percentage of sacral purchase (PoSP) for each screw, percentage of reduction (PoR), and pelvic canal width ratio (PCWR) were measured and calculated., Results: Eighty-two sacroiliac luxations were stabilized. Two 2.0 mm screws were used in 69 cases; two 2.4-mm screws in nine cases, and one 2.4 mm with one 2.0 mm screw in four cases. The mean PoSPs for lag and positional screws were 46% ± 12 and 31% ± 11, respectively. The median PoR was 89% (41 to 100). The mean PCWR was 1.23 ± 0.11. Clinical follow up was available for 42 cats with 53 sacroiliac luxations at a median of 87 days (36 to 2503). The full function was noted in 34 patients (81%). Screw failure occurred in five sacroiliac joints (4.7%), including loosening (n = 3), and breakage (n = 2) of the positional screws (n = 1). Pelvic canal diameter was maintained in all cases., Conclusion: Excellent functional and radiographic outcomes were obtained for cats with sacroiliac luxation stabilized with two sacroiliac screws., Clinical Significance: Feline sacroiliac luxation can be stabilized using two sacroiliac screws., (© 2024 American College of Veterinary Surgeons.)

Background: Total serum bilirubin concentration (TBIL) can provide useful information on several pathophysiological conditions in cats. Nevertheless, whether the variable severity classification of hyperbilirubinemia can reliably indicate certain disease processes or predict a biliary obstruction (BO) has not been investigated. Hypothesis/Objective: Determine if hyperbilirubinemia of variable severity can assist clinicians to identify BO, which often is considered a surgical emergency. Animals: Two‐hundred sixteen client‐owned cats. Methods: Data were retrospectively collected from all cats (January 2015‐August 2022) with an increased TBIL (>0.58 mg/dL [>10 μmol/L]) presented to 3 referral centers in the United Kingdom (UK). Presenting clinical features and diagnostic outcomes were collected. The predictive ability of TBIL to indicate BO was evaluated by multivariable binary logistic regression modeling and receiver operating characteristic (ROC) curves. Results: Median TBIL was 1.73 mg/dL (range, 0.59‐26.15; 29.5 μmol/L; range, 10.1‐447.1) with severity classification of hyperbilirubinemia categorized as mild (>0.58‐2.92 mg/dL; >10‐50 μmol/L; 68.1%), moderate (>2.92‐5.85 mg/dL; >50‐100 μmol/L; 17.6%), severe (>5.85‐11.70 mg/dL; >100‐200 μmol/L; 9.7%) and very severe (>11.70 mg/dL; >200 μmol/L; 4.6%). Biliary obstruction was present in 17 (7.9%) cats, all of which received recommendation for emergency surgery. Median TBIL in cats with BO (9.69 mg/dL; 165.7 μmol/L) differed significantly from those without obstruction (1.51 mg/dL; 25.8 μmol/L; P <.01). The optimal TBIL cut‐off to discriminate between cats with and without BO was ≥3.86 mg/dL (≥66 μmol/L) with a sensitivity of 94.1% and specificity of 82.4%. Using multivariable logistic regression, as age increased, the odds of BO increased significantly (odds ratio, 1.20; 95% confidence interval, 1.01‐1.42; P =.04). Conclusions and Clinical Importance: As part of a thorough clinical assessment, the severity classification of hyperbilirubinemia has the potential to predict the likelihood of a BO and to discriminate between cats that may or may not require surgery for BO at a suggested cut‐off of ≥3.86 mg/dL (≥66 μmol/L). Alongside TBIL, age is also useful when assessing for the likelihood of BO in a cat presented with hyperbilirubinemia. [ABSTRACT FROM AUTHOR]

Objective: To compare the outcome of the laparotomy-assisted endoscopic removal (LAER) of gastrointestinal foreign bodies (FBs) with traditional enterotomy, and to determine which factors affected the ability to remove FBs., Study Design: Retrospective observational study., Sample Population: Dogs and cats (n = 81) with gastrointestinal FBs., Methods: Dogs and cats were divided into Group 1 (LAER, n = 40) and Group 2 (Enterotomy, n = 41). The localization and characteristics of the FBs (sharp or blunt; discrete or linear; single or multiple) were evaluated statistically to identify the factors that affected the ability of LAER to remove, partially or completely, the FBs (χ 2 test). The length of the postoperative stay, postoperative analgesia, and resumption of spontaneous feeding were compared between groups (Mann-Whitney U-test). Short-term follow up (14 days) was recorded., Results: Laparotomy-assisted endoscopic removal allowed complete or partial removal of FBs in 35/40 dogs and cats, regardless of the characteristics or the localization of the FBs. The presence of intestinal wall damage (p = .043) was associated with the conversion to an enterotomy. Group 1 required a shorter postoperative hospital stay (p = .006), less need for analgesia (p < .001), and experienced a faster resumption of spontaneous feeding (p = .012), and similar complication rate to Group 2., Conclusion: Laparotomy-assisted endoscopic removal resulted in a faster postoperative recovery when compared with an enterotomy. The FBs' characteristics or localization did not affect the efficacy of the technique to remove FBs., Clinical Significance: Laparotomy-assisted endoscopic removal allows the removal of a variety of FBs, avoiding intestinal incision and resulting in a fast postoperative recovery., (© 2024 The Author(s). Veterinary Surgery published by Wiley Periodicals LLC on behalf of American College of Veterinary Surgeons.)

Objective: To report the technique and the outcome for the repair of pelvic fractures in cats using external skeletal fixation (ESF)., Study Design: Retrospective case series., Animals: Client-owned cats (n = 125)., Methods: Medical records of cats with pelvic fractures, treated with an ESF between June 2001 and June 2009, were reviewed. Preoperative, immediate postoperative, and more than 4 weeks' postoperative radiographs were compared. Clinical examination was performed 4 to 9 weeks following surgery. Longer term follow up (4 to 80 months) was conducted by client questionnaire., Results: No intraoperative complications occurred. There was no change in the pelvic canal width observed on follow-up radiographs (p = .16). Implant loosening was noted on follow-up radiographs in 16/125 (13%) of cases, and 67/803 (8%) pins were palpably loose at the time of frame removal. The mean time to frame removal was 37 ± 9 days. No long-term complications were reported. Long-term mean mobility score was 95 ± 5 and median lameness was 0 (range: 0-2)., Conclusion: An ESF may be successfully applied for the stabilization of various pelvic fractures in cats., Clinical Significance: The application of an ESF for the management of pelvic fractures in cats provides good outcomes., (© 2024 American College of Veterinary Surgeons.)

Copyright of Canadian Veterinary Journal / Revue Vétérinaire Canadienne is the property of Canadian Veterinary Medical Association and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Harran University Journal of the Faculty of Veterinary Medicine / Harran Üniversitesi Veteriner Fakültesi Dergisi is the property of Harran University, Faculty of Veterinary Medicine and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Veterinary Journal / Revue Vétérinaire Canadienne is the property of Canadian Veterinary Medical Association and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Case summary A 1-year-old neutered male domestic shorthair cat was referred with suspected uroperitoneum. Ultrasonography showed peritoneal effusion. CT further revealed a bilateral sacroiliac joint disruption associated with an overlapped dislocation of the pubic symphysis, resulting in an abnormal trajectory of the urethra with extramural urethral compression. An open reduction and internal fixation of the pubis with correction of the urethral trajectory was performed under general anaesthesia. The uroperitoneum was determined to originate from a cystocentesis. Relevance and novel information This report describes an unusual case of urethral obstruction secondary to overlapping dislocation of the pubic symphysis with urethral entrapment and concurrent bilateral sacroiliac luxation. To the authors' knowledge, acute urethral obstruction owing to fractures of the pubis, without urethral laceration, has never been described. [ABSTRACT FROM AUTHOR]

Type 1 diabetes (T1D) is characterized by the autoimmune-mediated attack of insulin-producing beta cells in the pancreas, leading to reliance on exogenous insulin to control a patient's blood glucose levels. As progress is being made in understanding the pathophysiology of the disease and how to better develop therapies to treat it, there is an increasing need for monitoring technologies to quantify beta cell mass and function throughout T1D progression and beta cell replacement therapy. Molecular imaging techniques offer a possible solution through both radiologic and non-radiologic means including positron emission tomography, magnetic resonance imaging, electron paramagnetic resonance imaging, and spatial omics. This commentary piece outlines the role of molecular imaging in T1D research and highlights the need for further applications of such methodologies in T1D. [ABSTRACT FROM AUTHOR]

Endometrial polyps are rare benign uterine masses exclusively reported in geriatric, entire, female dogs or spayed female dogs with ovarian remnant syndrome. A 12‐year‐old, female, ovariohysterectomised cocker spaniel was presented for hyporexia, progressive muco‐haemorrhagic vulval discharge, and an ultrasonographically detected caudal abdominal mass. Thoracic and abdominal computed tomography revealed that the mass originated from the uterine stump, with no evidence of metastasis. Surgical excision of the mass was performed, and histopathology of the mass was consistent with an endometrial polyp. The dog was confirmed to be neutered based on the absence of ovarian remnant found on computed tomography and during surgery, and the negative results of both anti‐Mullerian hormone test and human chorionic gonadotropin stimulated progesterone test. The dog fully recovered with complete resolution of clinical signs at 2‐week, 6‐month and 18‐month rechecks. The presenting case highlights the first reported case of an endometrial polyp in a spayed female dog. [ABSTRACT FROM AUTHOR]

Standard transthoracic echocardiography is considered the non-invasive gold standard for the diagnosis of most cardiac diseases. Defining reproducibility, repeatability, and reliability of this exam is imperative to reduce errors in clinical evaluations. The present study aimed at: (1) evaluating the reproducibility and repeatability of 15 echocardiographic parameters in dogs by analyzing measurements obtained from several operators with different levels of experience and comparing them to the ones obtained from two board-certified operators (gold standards - GSs); (2) assessing whether different formative paths have an influence on the variability of the echocardiographic measurements. Fifty-one operators have been included in this study, along with two diplomates of the European College of Veterinary Internal Medicine - Cardiology. Ten dogs were enrolled, 5 Golden Retrievers and 5 Cavalier King Charles Spaniels. Echocardiographic examination was performed on each dog by one GS and several operators on the same day. Results show the highest deviation from the GS and a poor inter-operator reproducibility for the M-mode measurements of the interventricular septum and the left ventricular free wall. Differently, M-mode-obtained internal diameters of the left ventricle in systole and diastole, and measurements of the aortic annulus and root show moderate to excellent intra- and inter-operator reliability and a good concordance with the GSs, demonstrating that all the operators correctly assess left ventricular systolic function and dilation, and evaluate the aortic valve. Furthermore, a specialist clinical activity, more than the acquired theoretical knowledge, affects the reliability of the echocardiographic examination by reducing the difference from the GS' measurements. [ABSTRACT FROM AUTHOR]

Background: Cholelithiasis is an uncommon and mainly incidental finding in dogs; current literature on this topic is scarce in cats. Hypothesis: Report prevalence, clinical presentation, management, and outcome of cholelithiasis in cats. Animals: Ninety‐eight cats with cholelithiasis. Methods: Retrospective multicenter case series. Electronic databases from 3 hospitals were searched for cats diagnosed with cholelithiasis by ultrasonography (US). Cholelithiasis was classified as incidental (IC) or symptomatic (SC) depending on clinicopathological signs, biliary tract US appearance, and presence of another disease potentially explaining the clinical presentation. Multivariate analysis was used to investigate factors associated with clinical expression of cholelithiasis and, within the SC group, survival. Results: The observed prevalence of cholelithiasis was 0.99% (95% confidence interval [CI], 0.79%‐1.19%) among cats that underwent abdominal US. Cholelithiasis was classified as IC in 41% and SC in 59%. Choleliths found in multiple locations within the biliary tract (odds ratio [OR], 8.11; 95% CI, 2.32‐34.15; P =.001) or associated with US signs of obstruction (OR, 18.47; 95% CI, 2.13‐2413.34; P =.004) were significantly associated with SC. Concurrent hepatobiliary diseases were suspected or confirmed in 83% of cases with SC. Forty‐three cats (74%) with SC survived to discharge. Biliary tract obstruction (BTO) was negatively associated with survival (OR, 13.87; 95% CI, 1.54‐124.76; P =.001). None of the cats with IC that had available follow‐up (47%) developed clinicopathological signs related to cholelithiasis. Conclusions and Clinical Importance: Cholelithiasis is uncommon and can be asymptomatic in cats. Symptomatic cholelithiasis frequently is associated with another hepatobiliary disease or BTO or both. Biliary tract obstruction is associated with poorer outcome. [ABSTRACT FROM AUTHOR]

Background: Bacterial infection of bile is a common cause of hepatobiliary disease in cats. Whether bile harbors a core microbiota in health or in cases of suspected hepatobiliary disease in cats is unknown. Objectives: Establish if gallbladder bile in apparently healthy cats harbors a core microbiota composed of bacterial taxa common to many individuals. Compare results of bile cytology, bile culture, and 16S rRNA gene amplicon sequencing in apparently healthy cats and cats with suspected hepatobiliary disease. Animals: Forty‐three client‐owned cats with suspected hepatobiliary disease and 17 control cats. Methods: Bile was collected by ultrasound guided cholecystocentesis (cats with suspected hepatobiliary disease) or laparotomy after euthanasia (controls). Bile samples underwent cytologic examination, aerobic and anaerobic culture, and DNA was extracted for 16S rRNA gene amplification and sequencing. Results: Microbiome sequencing did not identify a core microbiota in control cats or cats having bile sampled because of clinical suspicion for hepatobiliary disease. Microbiome profiles from control cats were indistinguishable from profiles obtained from sampling instruments and reagents that were not exposed to bile (technical controls). Bacterial taxa that could not be explained by contamination or off‐target amplification were identified only in samples from cats with bactibilia and positive bile culture results for Escherichia coli. In several E. coli positive samples, microbiome sequencing also identified a small number of potentially co‐infecting bacterial genera not identified by culture. Conclusions and Clinical Importance: Cat bile does not harbor a core microbiota. Uncultured bacteria may contribute to pathogenesis of hepatobiliary disease in cats with bile E. coli infection. [ABSTRACT FROM AUTHOR]

The field of regenerative medicine offers potential therapies for Type 1 Diabetes, whereby metabolically active cellular components are combined with synthetic medical devices. These therapies are sometimes referred to as "bioartificial pancreases." For these emerging and rapidly developing therapies to be clinically translated to patients, researchers must overcome not just scientific hurdles, but also navigate complex legal, ethical and psychosocial issues. In this article, we first provide an introductory overview of the key legal, ethical and psychosocial considerations identified in the existing literature and identify areas where research is currently lacking. We then highlight two principal areas of concern in which these discrete disciplines significantly overlap: 1) individual autonomy and 2) access and equality. Using the example of beta-cell provenance, we demonstrate how, by harnessing an interdisciplinary approach we can address these key areas of concern. Moreover, we provide practical recommendations to researchers, clinicians, and policymakers which will help to facilitate the clinical translation of this cutting-edge technology for Type 1 Diabetes patients. Finally, we emphasize the importance of exploring patient perspectives to ensure their responsible and acceptable translation from bench to body. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Veterinary Research / Revue Canadienne de Recherche Vétérinaire is the property of Canadian Veterinary Medical Association and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The pharmacokinetic profile of selected NSAIDs in southern black rhinoceros ( Diceros bicornis minor ) were studied. Phenylbutazone (PBZ), meloxicam (MEL), and firocoxib (FIR) were administered orally to five captive, black rhinoceros, and blood was collected at predetermined time points for NSAID quantification and noncompartmental pharmacokinetic (PK) analysis. Phenylbutazone 4.0 mg/kg PO q12h for three doses, MEL 0.3 mg/kg PO q24h administered twice, and a single oral dose of FIR 0.1 mg/kg, were tested with a minimum washout time of 2 wk. PBZ reached a median (range) peak concentration (C max ) of 9.42 (2.74-11.5) g/ml at a mean (range) time (T max ) of 6.00 (4.00 to >12.00) h, and the median (range) elimination half-life (T 1/2 ) was 6.07 (3.95-6.49) h. Phenylbutazone pharmacokinetic parameters for black rhinoceros in this study were similar to domestic horses. Meloxicam reached a median (range) C max of 0.576 (0.357-0.655) µg/ml at a median (range) time (T max ) of 6.00 (4.00-12.00) h; the median (range) T 1/2 of MEL was 14.0 (12.4-17.9) h. These results demonstrate that once-daily administration of MEL at 0.3 mg/kg resulted in a serum concentration of greater than 0.200 µg/ml from 2 to 24 h in four animals, which is within the analgesic range (0.200-0.400 µg/ml) for this drug in other species postulated by other studies. A single dose of firocoxib (0.1 mg/kg) reached a median (range) peak concentration (C max ) of 15.7 (9.65-17.3) ng/ml at a median (range) T max of 4.00 (4.00-6.00) h. The median (range) elimination T 1/2 of FIR was 4.96 (4.47-6.51) h, which is faster than in the horse. The data suggest that extrapolation from equine FIR dosage recommendations is inappropriate for black rhinoceros.

A 1-year-old Miniature Horse filly was presented for chronic lethargy and hyporexia. Elevated liver enzymes, bile acids, and ammonia were noted on bloodwork. The primary differential diagnosis was a portosystemic shunt (PSS). Three-phase computed tomographic angiography findings were consistent with a transhepatic portosystemic shunt. Percutaneous liver biopsy confirmed severe diffuse hepatic changes, most likely due to chronic pyrrolizidine alkaloid toxicosis, and medical management was elected. Based on an extensive literature review, this is the first report of a transhepatic portosystemic collateral vessel in a horse. Computed tomographic angiography is feasible and useful for the diagnosis of PSS in miniature horses., (© 2024 American College of Veterinary Radiology.)