Electromyographic evaluation of functional electrical stimulation to injured oculomotor nerve

Functional electrical stimulation delivered early after injury to the proximal nerve stump has been proposed as a therapeutic approach for enhancing the speed and specificity of axonal regeneration following nerve injury. In this study, the injured oculomotor nerve was stimulated functionally by an implantable electrode. Electromyographic monitoring of the motor unit potential of the inferior oblique muscle was conducted for 12 weeks in two injury groups, one with and one without electric stimulation. The results revealed that, at 2, 4, 6, 8 weeks after functional electric stimulation of the injured oculomotor nerve, motor unit potentials significantly increased, such that amplitude was longer and spike duration gradually shortened. These findings indicate that the injured oculomotor nerve has the potential for regeneration and repair, but this ability is not sufficient for full functional recovery to occur. Importantly, the current results indicated that recovery and regeneration of the injured oculomotor nerve can be promoted with functional electrical stimulation.

Dual neuronal response to tumor necrosis factor-alpha following spinal cord injury

BACKGROUND： Numerous studies have shown that tumor necrosis factor α （TNF-α） is closely correlated with spinal cord injury （SCI）, but the mechanisms of TNF-α and therapeutic treatments for SCI are still poorly understood. OBJECTIVE： To determine the role of TNF-α in the pathogenesis of SCI. DESIGN, TIME AND SETTING： An in vivo experiment based on genetically engineered animals was performed at the Medical University of South Carolina, Charleston, South Carolina, USA, between June 2007 and October 2008. MATERIALS： TNF-α transgenic rats （Xenogen Biosciences in Cranbury, New Jersey, USA） were utilized in this study. METHODS： TNF-α transgenic （tg） and wild-type （WT） rats underwent a complete single-level laminectomy at the 10^th thoracic vertebra （T10）. MAIN OUTCOME MEASURES： Motor function of rat hindlimb was assessed using the Basso, Beattie, and Bresnahan hindlimb locomotor rating scale. Histological evaluation of spinal cord tissue loss was conducted. Immunohistochemistry for astrocytes, microglia/macrophages, and TNF receptors （TNFRs） was performed on spinal cord tissue sections. TNF-α mRNA expression was detected by real-time polymerase chain reaction. The concentrations of nerve growth factor （NGF） and brain-derived neurotrophic factor （BDNF） in the supernatant were determined using an enzyme-linked immunosorbent assay kit for rat NGF or BDNF, respectively. The rats were injected subcutaneously with etanercept to verify that TNF-α was the direct effect of the modulation of behavioral and neurodegenerative outcomes in the TNF-α tg rats. RESULTS： TNF-α tg rats showed higher expression of TNF-α mRNA in the spinal cord prior to SCI. TNF-α tg rats showed worse motor deficits than WT rats in the acute period （〈 3 days） after SCI （P 〈 0.01）, while in the chronic period, TNF-α tg rats exhibited persistent elevated baseline levels of TNF-α mRNA and improved recovery in motor function and tissue healing compared to WT rats （P 〈 0.01 ）. Following SCI, the number of microglia/macrophages in TNF-α tg rat was always greater than in WT rat （P 〈 0.01）. There were no significant differences in NGF and BDNF levels in the supernatant of spinal cord homogenates. TNFR1 expression was significantly greater in the TNF-α tg rats compared to the WT rats （P 〈 0.01）. However, TNFR2 expression did not reveal a significant increase in the TNF-α tg rats compared to the WT rats. Finally, treatment with etanercept reduced injury acutely, but exacerbated the injury chronically. CONCLUSION： Overexpression of TNF-α is deleterious in the acute phase, but beneficial in the chronic phase in the response to SCI. The role of TNF-α post-injury may depend on TNF-α expression in the spinal cord and its differential binding to TNFRI. Our observations may have clinical relevance that antagonists or inhibitors of TNF-α could be administered within the early time window post-injury, and appropriate amounts of TNF-α could be administered during the chronic stage, in order to improve the final neurological recovery in patients with SCI.

A standardized method to create peripheral nerve injury in dogs using an automatic non-serrated forceps

This study describes a method that not only generates an automatic and standardized crush injury in the skull base, but also provides investigators with the option to choose from a range of varying pressure revels. We designed an automatic, non-serrated forceps that exerts a varying force of 0 to 100 g and lasts for a defined period of 0 to 60 seconds. This device was then used to generate a crush injury to the right oculomotor nerve of dogs with a force of 10 g for 15 seconds, resulting in a deficit in the pupil-light reflex and ptosis. Further testing of our model with Toluidine-blue staining demonstrated that, at 2 weeks post-surgery disordered oculomotor nerve fibers, axonal loss, and a thinner than normal myelin sheath were visible. Electrophysiological examination showed occasional spontaneous potentials. Together, these data verified that the model for oculomotor nerve injury was successful, and that the forceps we designed can be used to establish standard mechanical injury models of peripheral nerves.

A Study on Karyotypes and Ag-NORs of Odontobutis potamophila

In order to obtain cytogenetic data of Odontobutis potamophila,head-kidney cells were collected as experimental materials to prepare chromosome specimen. The karyotypes of O. potamophila and the distribution and amount of transcriptionally active nucleolar organizer regions on chromosomes were analyzed by Giemsa staining and Ag-NORs. The results showed that the number of diploid chromosomes of O. potamophila was 44; the genome of O. potamophila was composed of 44 telocentric chromosomes; the karyotype formula was 2 n = 44 t,NF = 44; Ag-NORs were found in the paracentromeric region of chromosome. The results may lay the foundation for revealing the genetic pattern and chromosomal evolution of O. potamophila and contribute to further genetic breeding of O. potamophila.