Feasibility of laparoscopic stapled partial cystectomy in canine cadavers.

OBJECTIVE: To describe a technique for laparoscopic partial cystectomy and evaluate sealing of canine urinary bladder tissue with an endoscopic stapler. STUDY DESIGN: Prospective, cadaveric study. SAMPLE POPULATION: Eleven canine cadavers. METHODS: Laparoscopic partial cystectomy was performed with an endoscopic gastrointestinal anastomosis (GIA) stapler. Leak testing and urodynamic evaluation was performed to measure intravesical pressure at initial leakage and catastrophic failure or the maximum pressure at which intravesical pressure plateaued. Surgical time, complications, and site of leakage were also recorded. RESULTS: Laparoscopic partial cystectomy was successfully performed in 10 of 11 cadavers. Median procedure time was 13.6 min (10.1-15.2 min). Median intravesical pressure at initial leakage was 31 mmHg (28-56 mmHg) with a median increase from initial pressure of 15 mmHg (11-37 mmHg). No catastrophic failure of the cystectomy site was observed during leak testing. Intravesical pressure plateaued at a median of 52 mmHg (39-73 mmHg), which was a median of 13 mmHg (8-23 mmHg) higher than intravesical pressure at initial leakage. The median total volume infused at the time of plateau of intravesical pressure was 89 mL (58-133 mL). CONCLUSION: Laparoscopic stapled partial cystectomy was feasible in canine cadavers. Endoscopic GIA staplers appear to seal the canine urinary bladder with minimal leakage. CLINICAL SIGNIFICANCE: Use of an endoscopic GIA stapler may provide a minimally invasive option for partial cystectomy in dogs. Further evaluation for application to clinical cases is warranted.

Clinical presentation and short-term outcomes of dogs ≥15 kg with extrahepatic portosystemic shunts.

OBJECTIVE: To describe demographics, clinical presentation, shunt anatomy, clinical progression, and complications in large dogs ≥15 kg with single extrahepatic portosystemic shunts (EHPSS) treated with or without surgery. STUDY DESIGN: Multicenter retrospective (10 university hospitals, one private referral institution). ANIMALS: Dogs ≥15 kg (n = 63). METHODS: Medical records of dogs ≥15 kg diagnosed with EHPSS between January 01, 2005 and December 31, 2020 were reviewed. Dogs had a minimum follow-up of 90 days. Signalment, clinical signs, diagnostics, shunt anatomy, treatment interventions, and perioperative complications were assessed. RESULTS: Median age was 21.9 months (IQR: 9-36.8). The breed most represented was the Golden retriever (17/63 dogs). Portocaval (17/63) and splenocaval (15/63) shunt configurations were most common. Portal vein hypoplasia was noted in 18 imaging reports. Of the surgically treated dogs, 14/45 (35.6%) had short-term complications, and 3/45 (6.7%) had shunt-related deaths. Medical management was discontinued in 15/40 and reduced in 9/40 of surviving dogs who had surgical attenuation. All medically managed, nonattenuated dogs (18/18) were maintained on their original shunt-related medication regimens. CONCLUSIONS: Clinical presentation of dogs ≥15 kg with extrahepatic portosystemic shunts was similar to the more commonly reported small breed dogs. Surgical management of single EHPSS in large dogs ≥15 kg had similar clinical short-term outcomes as small breed dogs. CLINICAL SIGNIFICANCE: Clinicians should be aware that large breed dogs with EHPSS share similar characteristics and clinical outcomes to small breed dogs. The significance of the presence of a hypoplastic portal vein warrants further research. Surgical treatment is a viable option for large breed dogs with EHPSS.

Ventral hippocampal formation is the primary epileptogenic zone in a rat model of temporal lobe epilepsy.

Temporal lobe epilepsy is common, but mechanisms of seizure initiation are unclear. We evaluated seizure initiation in female and male rats that had been systemically treated with pilocarpine, a widely used model of temporal lobe epilepsy. Local field potential recordings from many brain regions revealed variable sites of earliest recorded seizure activity, but mostly the ventral hippocampal formation. To test whether inactivation of the ventral hippocampal formation would reduce seizures, mini-osmotic pumps were used to continually and focally deliver tetrodotoxin. High doses of tetrodotoxin infused unilaterally into the ventral hippocampal formation blocked seizures reversibly but also reduced local field potential amplitudes in remote brain regions, indicating distant effects. A lower dose did not reduce local field potential amplitudes in remote brain regions but did not reduce seizures when infused unilaterally. Instead, seizures tended to initiate in the contralateral ventral hippocampal formation. Bilateral infusion of the lower dose into the ventral hippocampal formation reduced seizure frequency 85%. Similar bilateral treatment in the amygdala was not effective. Bilateral infusion of the dorsal hippocampus reduced seizure frequency, but only 17%. Together, these findings reveal that the ventral hippocampal formation is a primary bilaterally independent epileptogenic zone, and the dorsal hippocampus is a secondary epileptogenic zone in pilocarpine-treated rats. This is consistent with many human patients, and the results further validate the local field potential method for identifying seizure onset zones. Finally, the findings are more consistent with a focal mechanism of ictogenesis rather than one involving a network of interdependent nodes.SIGNIFICANCE STATEMENT:To better understand how seizures start, investigators need to know where seizures start in the animal models they study. In the widely used pilocarpine-treated rat model of temporal lobe epilepsy, earliest seizure activity was most frequently recorded in the ventral hippocampal formation. Confirming the primary role of the ventral hippocampal formation, seizure frequency was reduced most effectively when it was inactivated focally, bilaterally, and continually with infused tetrodotoxin. These findings suggest the ventral hippocampal formation is the primary site of seizure initiation in this animal model of temporal lobe epilepsy, consistent with findings in many human patients.

Acute restraint stress reduces hippocampal oxidative damage and behavior in rats: Effect of S-allyl cysteine.

AIMS: This simple study was designed to investigate whether acute restraint stress can generate changes in behavioral tests and hippocampal endpoints of oxidative stress in rats, and if the antioxidant S-allyl cysteine (SAC) can prevent these alterations. MATERIALS AND METHODS: We evaluated motor activity, forced swimming and anxiety behavior, as well as the hippocampal levels of lipid peroxidation and the activities of glutathione-related enzymes in animals submitted to mild immobilization. The effect of SAC (100 mg/kg, i.p.), given to rats every day 30 min before starting the immobilization session, was also investigated. Immobilization (restraint) stress was induced for a period of 6 h per day for five consecutive days. KEY FINDINGS: Our results indicate that, under the tested conditions, acute restraint stimulates compensatory behavioral tasks (motor activity, anxiety and forced swimming) to counteract the stressing conditions prevailing, and selectively increased the levels of lipid peroxidation and the enzyme activities of glutathione-S-transferase (GST) and glutathione peroxidase (GPx) in the hippocampus also as adaptive responses. SAC exhibited preventive effects in the stressed group as it improved behavior, reduced lipid peroxidation and prevented the increase of GST and GPx activities, suggesting that this antioxidant blunted primary pro-oxidative stimuli induced by restraint stress. SIGNIFICANCE: Findings of this work also confirm that the use of antioxidants such as SAC can provide effective protection against the acute oxidative damage associated with anxiety produced by stressing conditions.