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991.
992.
Simple measurement of spinal cord evoked potential: a valuable data source in the rat spinal cord injury model. 总被引:1,自引:0,他引:1
Jong-Pil Park Ki-Jeong Kim Ji Hoon Phi Chul-Kee Park Jong-Hoon Kim Hyo Jin Kang Dohun Lee Kyu Hyun Han Kyu-Chang Wang Sun Ha Paek 《Journal of clinical neuroscience》2007,14(11):1099-1105
Measurement of spinal cord evoked potentials (SCEPs) is proposed as a means of predicting locomotion outcome in the rat spinal cord injury (SCI) model. Using 55 rats, three reproducible peak waves (waves I, II and III) were observed during stimulation at the C7 level with recording at the L1 epidural space. Hemisection at the T13 level showed three wave loss patterns: wave III loss only, loss of both wave II and III, and loss of all three waves. Defining an ideal SCI model as establishment of stable monoparesis or paraparesis, all animals in the wave II-III loss group showed favorable results. Histological data and electrophysiological properties allowed reasonable assumptions of wave origin: wave I from extrapyramidal tracts, wave II from the ventral corticospinal tract, and wave III from the dorsal corticospinal tract. Complete destruction of pyramidal tracts in both dorsal and ventral fibers was essential for long-term impairment of locomotion. 相似文献
993.
Lixian Zhang Peng Shi El‐Kebir Boukas Changhong Wang 《Optimal control applications & methods.》2006,27(5):273-291
In this paper, the problem of designing H∞ state‐feedback controllers for switched linear discrete‐time systems with polytopic uncertainties is investigated. Two approaches on designing robust and parameter‐dependent H∞ controllers are proposed and the existence conditions of the desired controllers are derived and formulated in terms of a set of linear matrix inequalities. By solving the corresponding convex optimization problem, the desired controllers are obtained, respectively, and different optimal H∞ noise‐attenuation level bounds of corresponding closed‐loop systems are given as well. The designed controllers have their own advantages and disadvantages regarding the conservatism and realization complexity. An illustrative example emerging in networked control systems (NCS) and numerical simulations are presented to show the applicability and effectiveness of the obtained theoretic results. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
994.
Henry Ahn Payam Mousavi Lee Chin Sandra Roth Joel Finkelstein Alex Vitken Cari Whyne 《European spine journal》2007,16(8):1171-1178
A biomechanical study comparing simulated lytic vertebral metastases treated with laser-induced thermotherapy (LITT) and vertebroplasty
versus vertebroplasty alone. To investigate the effect of tumor ablation using LITT prior to vertebroplasty on biomechanical
stability and cement fill patterns in a standardized model of spinal metastatic disease. Vertebroplasty in the metastatic
spine is aimed at reducing pain, but is associated with risk of cement extravasation in up to 10%. Six pairs of fresh-frozen
cadaveric thoracolumbar spinal motion segments were tested in axial compression intact, with simulated metastases and following
percutaneous vertebroplasty with or without LITT. Canal narrowing under load, pattern of cement fill, load to failure, and
LITT temperature and pressure generation were collected. In all LITT specimens, cement filled the defect without extravasation.
The canal extravasation rate was 33% in specimens treated without LITT. LITT and vertebroplasty yielded a trend toward improved
posterior wall stability (P = 0.095) as compared to vertebroplasty alone. Moderate rises in temperature and minimal pressure generation was seen during
LITT. In this model, elimination of tumor by LITT, facilitates cement fill, enhances biomechanical stability and reduces the
risk of cement extravasation. 相似文献
995.
996.
997.
Jeong-Hoon Oh Keehyun Park Seung Joo Lee You Ree Shin Yun-Hoon Choung 《Otolaryngology--head and neck surgery》2007,136(1):87-91
OBJECTIVES: To analyze the clinical characteristics and treatment results between bilateral (bi-) and unilateral (uni-) sudden sensorineural hearing loss (SSNHL). STUDY DESIGN AND SETTING: A retrospective study. METHODS: Three hundred twenty-four patients with SSNHL were classified into two groups; simultaneous bi-SSNHL (n = 16) and uni-SSNHL (n = 308). We compared clinical characteristics, medical history, hearing level, and treatment results between the 2 groups. RESULTS: The incidence of bi-SSNHL was 4.9 percent of overall patients with SSNHL. Bi-SSNHL occurs more commonly in patients of older age, with preexisting diabetes mellitus, and lipid panel abnormalities compared with uni-SSNHL. Ten patients (62.5%) in the bi-SSNHL group showed hearing recovery in 1 or both ears compared with 56.5 percent of patients with uni-SSNHL. Only 12 (37.5%) of all 32 ears recovered in bi-SSNHL, which was significantly lower than in uni-SSNHL. CONCLUSION: Bi-SSNHL has a very low incidence and lower recovery rate than uni-SSNHL. Recognition of similarities and differences between bilateral and unilateral SSNHL can help in counseling and managing the patients. 相似文献
998.
Sang-Won Yeo Dong-Hee Lee Beom-Cho Jun So-Young Park Yong-Soo Park 《Otolaryngology--head and neck surgery》2007,136(2):221-224
OBJECTIVE: To evaluate the time-dependent progress and delayed improvement in patients who were treated with combination therapy including oral corticosteroid for idiopathic sudden sensorineural hearing loss. STUDY DESIGN AND SETTING: This retrospective study at a secondary referral and university-based center included 156 patients who were treated by 10-day course of admission therapy and followed for at least three months. RESULTS: Of 121 patients who recovered over three months of follow-up, 45.5% showed a delayed recovery after the end of 10-day course of therapy. Of these 55 patients, 78.2% recovered within one month, 5.5% recovered within one to two months, 12.7% recovered in two to three months, and 3.6% recovered later than three months after discharge. CONCLUSIONS: This study describes the long-term results for a three-month retrospective series of 156 patients diagnosed with idiopathic sudden sensorineural hearing loss, although this result should be further studied by additional research. 相似文献
999.
MR imaging of pineal cysts 总被引:2,自引:0,他引:2
Identification of pineal cysts with imaging modalities other than magnetic resonance (MR) has been infrequent, despite a reported autopsy incidence of as high a 40%. We recently identified 15 patients in whom pineal cysts were seen on MR. These cysts ranged from 5 to 15 mm in maximum diameter. The cyst walls were thin, usually measuring less than 2 mm. The signal characteristics of the fluid within the cysts paralleled that of CSF, although it differed somewhat in signal intensity from CSF collections in which there was pulsatile motion. All lesions were midline in location. There was no significant mass effect, although mild flattening of the superior colliculi could be seen. Two cases were operated on; at operation, typical pineal cysts were found, with one containing hemosiderin-laden proteinaceous material, which accounted for its markedly higher signal intensity. It is important that this entity be recognized so that these lesions are not confused with pineal tumors. 相似文献
1000.
The glomerular filtration rate (GFR), renal plasma flow (RPF) and renal blood flow (RBF) were all markedly decreased in rats given an adenine diet as the period of adenine administration lengthened. Concurrently, the urinary excretions of prostaglandin E2 (PGE2) and 6-keto-prostaglandin F1 alpha(6-keto-PGF1 alpha) decreased gradually in parallel with the renal function parameters, whereas the urinary excretion of thromboxane B2 (TXB2) increased markedly. These findings suggest the involvement of prostaglandin in the renal circulation. 相似文献