EMG Testing throughout behavioral recovery after rat sciatic nerve crush injury results in exuberant motoneuron dendritic hypertrophy.

Background: Peripheral nerve injury (PNI) is the most common type of nerve trauma yet, while injured motoneurons exhibit a robust capacity for regeneration, behavioral recovery is protracted and typically poor. Neurotherapeutic approaches to PNI and repair have primarily focused on the enhancement of axonal regeneration, in terms of rate, axonal sprouting, and reconnection connectivity. Both electrical stimulation (ES) and treatment with androgens [e.g., testosterone propionate (TP)] have been demonstrated to enhance axonal sprouting, regeneration rate and functional recovery following PNI. To date, very little work has been done to examine the effects of ES and/or TP on dendritic morphology and organization within the spinal cord after PNI. Objective: The objective of the current study was to examine the impact of treatment with TP and ES, alone or in combination, on the dendritic arbor of spinal motoneurons after target disconnection via sciatic nerve crush injury in the rat. Methods: Rats received a crush injury to the sciatic nerve. Following injury, some animals received either (1) no further treatment beyond implantation with empty Silastic capsules, (2) electrical nerve stimulation immediately after injury, (3) implantation with Silastic capsules filled with TP, or (4) electrical nerve stimulation immediately after injury as well as implantation with TP. All of these groups of axotomized animals also received bi-weekly electromyography (EMG) testing. Additional groups of intact untreated animals as well as a group of injured animals who received no further treatment or EMG testing were also included. Eight weeks after injury, motoneurons innervating the anterior tibialis muscle were labeled with cholera toxin-conjugated horseradish peroxidase, and dendritic arbors were reconstructed in three dimensions. Results: After nerve crush and ES and/or TP treatment, motoneurons innervating the anterior tibialis underwent marked dendritic hypertrophy. Surprisingly, this dendritic hypertrophy occurred in all animals receiving repeated bi-weekly EMG testing, regardless of treatment. When the EMG testing was eliminated, the dendritic arbor extent and distribution after nerve crush in the treated groups did not significantly differ from intact untreated animals. Conclusions: The ability of repeated EMG testing to so dramatically affect central plasticity following a peripheral nerve injury was unexpected. It was also unexpected that gonadal steroid hormones and/or ES, two neurotherapeutic approaches with demonstrated molecular/behavioral changes consistent with peripheral improvements in axonal repair and target reconnection, do not appear to impact central plasticity in a similar manner. The significance of peripheral EMG testing and resulting central plasticity reorganization remains to be determined.

A rat model for intracranial facial nerve crush injuries.

OBJECTIVE: (1) Explain the need for an animal model to study intracranial injuries to the facial nerve. (2) Describe various techniques attempted to identify and crush the intracranial segment of the facial nerve in a rat model. (3) Describe in detail a successful rat model of intracranial facial nerve crush injury. STUDY DESIGN: Randomized controlled animal study. SETTING: Animal laboratory. SUBJECTS AND METHODS: Multiple attempts at surgical approaches to the cerebellopontine angle were attempted on cadaveric rats. Once a successful approach was derived, this was used on 19 live rats under anesthesia. Fourteen rats had a 1-minute facial nerve crush performed, and 5 had a sham surgery with complete surgical exposure of the facial nerve but no crush. Rats were followed for a 12-week duration evaluating immediate postoperative facial nerve function, complications, and survival. RESULTS: All 14 (100%) rats that underwent surgery with crush injury had complete facial paralysis postoperatively. Complete facial paralysis was defined as loss of eye-blink reflex, flat vibrissae, and lack of vibrissae movement. The 5 sham surgery rats had complete facial function postoperatively. Surgery was performed by 2 separate surgeons with no difference in outcome between the 2. Complications occurred in only 1 animal (1/19, 5.3%), which was a corneal abrasion requiring sacrifice. CONCLUSION: Our group describes a consistent method for performing an intracranial crush injury in the rat. This new model and its applications in translational facial nerve research are promising, particularly with tumors or lesions at the cerebellopontine angle.

Impact of a dual PharmD/MBA degree on graduates' academic performance, career opportunities, and earning potential.

OBJECTIVE: To evaluate the academic experience and satisfaction of students who completed a dual PharmD/MBA degree program and the program's long-term impact on the students' career choice and earning potential. METHODS: GPAs, job placement, and starting job salaries were compared between graduates who completed the dual PharmD/MBA program and those who completed only the PharmD program. A satisfaction survey instrument was administered to 17 students who completed the dual PharmD/MBA degree program in May 2007. Data from a standardized job placement and starting salary survey instrument completed by all PharmD graduates were also obtained, as well as all students' final grade point averages (GPAs). GPAs, job placement, and starting job salaries were compared between graduates who had completed the dual PharmD/MBA program and those who had completed only the PharmD program. RESULTS: The graduating GPAs of dual-degree students were higher than those of both pharmacy (3.52 vs 3.41, p > 0.10) and business (3.82 vs. 3.68, p = 0.018) students not enrolled in the dual-degree program. Dual-degree students were slightly less likely to enter a residency (17% vs. 27%, p = 0.44) than other pharmacy graduates. Among those who elected not to pursue a residency, both mean starting salaries ($111,090 vs. $101,965) and mean total first-year compensation ($127,290 vs. $110,388) were significantly higher for dual-degree graduates compared to the PharmD graduates. CONCLUSIONS: Students enrolled in the dual-degree program did slightly better academically than students who completed only the MBA or PharmD programs and indicated a high level of satisfaction with the program. Dual-degree graduates reported increased career opportunities and were slated to earn significantly more during their first year in the workforce. These results affirm continuation of our program and make the case for support of similar programs across the nation.