Effect of deep brain stimulation on substantia nigra neurons in a rat model of Parkinson's disease / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Parkinson's disease (PD) is a common neurodegenerative disease, which occurs mainly in the elderly. Recent studies have demonstrated that apoptosis plays an important role in the occurrence and development of PD. Subthalamic nucleus deep brain stimulation (STN-DBS) has been recognized as an effective treatment for PD. Recent clinical observations have shown that STN-DBS was able to delay early PD progression, and experiments in animal models have also demonstrated a protective effect of STN-DBS on neurons. However, the correlation between the neuron-protective effect of STN-DBS and the progression of substantia nigra pars compacta (SNc) neuronal apoptosis is still unknown. The aim of this study was to investigate the protective effect and potential mechanism of STN-DBS on SNc neurons in PD rats.</p><p><b>METHODS</b>After the establishment of a PD rat model by unilateral/2-point injection of 6-hydroxydopamine in the medial forebrain bundle of the brain, DBS by implanting electrodes in the STN was administered. Behavioral changes were observed, and morphological changes of SNc neurons were analyzed by Nissl staining and DNA in situ end-labeling. Through extracellular recording of single neuron discharges and microelectrophoresis, the causes of and changes in SNc excitability during STN-DBS were analyzed, and the protective effect and potential mechanism of action of STN-DBS on SNc neurons in PD rats was investigated.</p><p><b>RESULTS</b>SNc neuron apoptosis was significantly decreased (P < 0.05) in the stimulation group, compared with the sham stimulation PD group. Spontaneous discharges of SNc neurons were observed in normal rats and PD model rats, and the mean frequency of spontaneous discharges of SNc neurons in normal rats ((40.65 ± 11.08) Hz) was higher than that of residual SNc neurons in PD rats ((36.71 ± 9.23) Hz). Electrical stimulation of the STN in rats was associated with elevated excitation in unilateral SNc neurons. However, administering the gamma-aminobutyric acid receptor blocker, bicuculline significantly reduced SNc neuron excitation, but the change in SNc neuron excitation was not present when MK801, a glutamate receptor blocker, was administered.</p><p><b>CONCLUSIONS</b>High-frequency stimulation of the STN has a protective effect on SNc neurons in PD rats. The possible molecular mechanism may be related to changes in the distribution and metabolism of neurotransmitters in the SNc region.</p>

Anterior and middle skull base reconstruction after tumor resection / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Surgical management of skull base tumors is still challenging today due to its sophisticated operation procedure. Surgeons who specialize in skull base surgery are making endeavor to promote the outcome of patients with skull base tumor. A reliable skull base reconstruction after tumor resection is of paramount importance in avoiding life-threatening complications, such as cerebrospinal fluid leakage and intracranial infection. This study aimed at investigating the indication, operation approach and operation technique of anterior and middle skull base reconstruction.</p><p><b>METHODS</b>A retrospective analysis was carried out on 44 patients who underwent anterior and middle skull base reconstruction in the Department of Neurosurgery at Beijing Tiantan Hospital between March 2005 and March 2008. Different surgical approaches were selected according to the different regions involved by the tumor. Microsurgery was carried out for tumor resection and combined endoscopic surgery was performed in some cases. According to the different locations and sizes of various defects after tumor resection, an individualized skull base soft tissue reconstruction was carried out for each case with artificial materials, pedicled flaps, free autologous tissue, and free vascularized muscle flaps, separately. A skull base bone reconstruction was carried out in some cases simultaneously.</p><p><b>RESULTS</b>Soft tissue reconstruction was performed in all 44 cases with a fascia lata repair in 9 cases, a free vascularized muscle flap in 1 case, a pedicled muscle flap in 14 cases, and a pedicled periosteal flap in 20 cases. Skull base bone reconstruction was performed on 10 cases simultaneously. The materials for bone reconstruction included titanium mesh, free autogenous bone, and a Medpor implant. The result of skull base reconstruction was satisfactory in all patients. Postoperative early-stage complications occurred in 10 cases with full recovery after conventional treatment.</p><p><b>CONCLUSIONS</b>The specific characteristics of skull base defects in various regions require different reconstruction materials and methods. The individualized reconstruction based on different skull base defects can achieve satisfactory results.</p>

Endoscopic endonasal surgery for meningoencephalocele / 中华耳鼻咽喉头颈外科杂志

<p><b>OBJECTIVE</b>To investigate the management experience with transnasal endoscopic technique for meningoencephalocele.</p><p><b>METHODS</b>Nine patients with endonasal encephalomeningocele were managed by transnasal endoscopic surgery, and the skull base defect was repaired by fascia.</p><p><b>RESULTS</b>Eight cases were successfully managed at the time of the first operation, and no relapse case was found during 1 to 4 years follow-up. Only one case of a two years old child relapsed with cerebrospinal fluid rhinorrhea one month after operation. During the second operation, titanium mesh uncovering was found, and replacement of titanium mesh by fascia via skull base defect was done, without relapse one and half years after the second operation. Another case of a one year old child got a fever one day after operation, but no white blood cell was found in the cerebrospinal fluid, and the temperature recovered to normal after release cerebrospinal fluid management. There were no complications of cranial infection, hemorrhage, edema and water retention in brain to be found in all cases.</p><p><b>CONCLUSIONS</b>It is not only minimally invasive, safety and efficiency of transnasal endoscopic technique for meningoencephalocele, but also had a clear operating view for better recolonization of the position of leak and the structure of operating field, therefore, transnasal endoscopic technique is the first choice for the management of endonasal encephalomeningocele. The accurate localization of leak and selection of the appropriate repairing materials are the key point for the successful operation.</p>