Alopecia and Dermatitis Caused by Lepoarcarus gibbus in a New Zealand White Rabbit (Oryctolagus cuniculus) – Clinical and Parasitological Diagnosis and Treatment

Aim: Ectoparasites associated dermatological disorders are frequently encountered in laboratory and pet rabbit medicine practice, however, L. gibbus is the only ectoparasite rarely reported in either pet and laboratory rabbits or hares as L. gibbus are usually asymptomatic. The aim of the present report is to describe a case of alopecia and dermatitis associated with Lepoarcarus gibbis in a rabbit from India. Presentation of Case: A 1.5 year old female New Zealand White rabbit was presented to the Dermatology Unit with erythema and poorly demarcated alopecia on the dorsal neck and face. A skin scraping and coat brushings were performed. On microscopic evaluation of hair samples, L. gibbus infestation was confirmed. Treatment with ivermectin (0.3 mg/kg) biweekly once for 3 doses proved effective. Discussion and Conclusion: L.gibbus may be presented with severe hairfall in the absence of other mites and treatment with ivermectin is effective. Based on the literature research this may be the first case report on alopecia and dermatitis due to L.gibbus in rabbit from India. Further studies should be planned on the prevalence of the mite as it is reported to have zoonotic potential.

Electroporation safety factor of 300 nanosecond and 10 millisecond defibrillation in Langendorff-perfused rabbit hearts

Aims Recently, a new defibrillation modality using nanosecond pulses was shown to be effective at much lower energies than conventional 10 millisecond monophasic shocks in ex vivo experiments. Here we compare the safety factors of 300 nanosecond and 10 millisecond shocks to assess the safety of nanosecond defibrillation. Methods and results The safety factor, i.e. the ratio of median effective doses (ED50) for electroporative damage and defibrillation, was assessed for nanosecond and conventional (millisecond) defibrillation shocks in Langendorff-perfused New Zealand white rabbit hearts. In order to allow for multiple shock applications in a single heart, a pair of needle electrodes was used to apply shocks of varying voltage. Propidium iodide (PI) staining at the surface of the heart showed that nanosecond shocks had a slightly lower safety factor (6.50) than millisecond shocks (8.69), p = 0.02; while PI staining cross-sections in the electrode plane showed no significant difference (5.38 for 300 ns shocks and 6.29 for 10 ms shocks, p = 0.22). Conclusions In Langendorff-perfused rabbit hearts, nanosecond defibrillation has a similar safety factor as millisecond defibrillation, between 5 and 9, suggesting that nanosecond defibrillation can be performed safely.

Using an impact hammer to perform biomechanical measurements during osteotomies: Study of an animal model

Osteotomies are common surgical procedures used for instance in rhinoplasty and usually performed using an osteotome impacted by a mallet. Visual control being difficult, osteotomies are often based on the surgeon proprioception to determine the number and energy of each impact. The aim of this study is to determine whether a hammer instrumented with a piezoelectric force sensor can be used to (i) follow the displacement of the osteotome and (ii) determine when the tip of the osteotome arrives in frontal bone, which corresponds to the end of the osteotomy pathway. Seven New Zealand White rabbit heads were collected, and two osteotomies were performed on their left and right nasal bones using the instrumented hammer to record the variation of the force as a function of time during each impact. The second peak time τ was derived from each signal while the displacement of the osteotome tip D was determined using video motion tracking. The results showed a significant correlation between τ and D ( ρ2 = 0.74), allowing to estimate the displacement of the osteotome through the measurement of τ. The values of τ measured in the frontal bone were significantly lower than in the nasal bone ( p<10−10), which allows to determine the transition between the nasal and frontal bones when τ becomes lower than 0.78 its initial averaged value. Although results should be validated clinically, this technology could be used by surgeons in the future as a decision support system to help assessing the osteotome environment.