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21.
Researchers usually employ orthogonal arrays or D-optimal designs with little or no attribute overlap in stated-choice surveys. The challenge is to balance statistical efficiency and respondent burden to minimize the overall error in the survey responses. This study examined whether simplifying the choice task, by using a design with more overlap, provides advantages over standard minimum-overlap methods. We administered two designs for eliciting HIV test preferences to split samples. Surveys were undertaken at four HIV testing locations in San Francisco, California. Personal characteristics had different effects on willingness to pay for the two treatments, and gains in statistical efficiency in the minimal-overlap version more than compensated for possible imprecision from increased measurement error.  相似文献   
22.
应重视口腔颌面部恶性肿瘤的综合序列治疗   总被引:11,自引:2,他引:9  
口腔颌面部恶性肿瘤约占全身恶性肿瘤的3%,虽然所占比例不高,但l大l其解剖部位特殊.涉及美观和重要的生理功能,冈此对患者机体和心理的影响不容忽视。早期(Ⅰ、Ⅱ期)口腔颌面部恶性肿瘤无论采用手术和(或)放射治疗,均能取得良好效果。但遗憾的是,大多数患者就诊时,已属局部一区域晚期(Ⅲ、Ⅳ期)。由于受到局部解剖和维持功能的限制,单纯通过扩大手术切除范围和改进现有手术技术,除能改善患者生存质量外,已无法提高此类患者的生存率,延长其生存时间。  相似文献   
23.
颈椎管哑铃形肿瘤的显微外科治疗   总被引:2,自引:1,他引:1  
目的探讨不同入路显微手术切除颈椎管哑铃形肿瘤的手术方法,总结其主要优点和术后并发症情况。方法2004年5月至2006年7月共收治16例颈椎管哑铃形肿瘤,其中5例肿瘤最大径超过5cm。5例巨大肿瘤中4例位于上颈段,采用侧方改良的极外侧入路(后外侧肌间入路), 1例外院手术复发的巨大肿瘤位于中颈段,采用分次后正中和前路联合切除并行后方和前方内固定加前方植骨融合;1例肿瘤椎管外部分向前方生长,采用颈前入路切除后行前方植骨融合加内固定,其余10例采用后正中入路,其中1例超过中线的肿瘤采用全椎板切除加椎管成形,7例半椎板切除, 1例复发肿瘤原路切除,1例未切除椎板切除肿瘤。结果手术全切肿瘤14例,次全切2例。所有病例术后症状均有明显改善,其中2例巨大肿瘤患者术后出现低氧血症,重新气管插管后逐渐恢复, 1例巨大肿瘤患者术后脑脊液漏皮下积液,经穿刺置管引流数日后恢复正常。其中12例随访9-18个月,无一例复发或出现脊柱不稳定的情况。结论对于颈椎管哑铃形肿瘤,应尽可能采用创伤小的手术方式,在切除肿瘤的同时,减少棘突、韧带、椎板以及小关节的破坏,减小创伤和对脊柱稳定性的破坏,预防脊柱后凸和侧凸畸形的发生。极外侧入路适用于微创切除体积较大的高颈段椎管哑铃形肿瘤,较小的肿瘤可以采用后正中入路半椎板开窗手术,对骨质破坏严重者需在切除肿瘤后行内固定手术。  相似文献   
24.
目的探讨经历不同时间快速眼动(REM)睡眠剥夺对大鼠皮质及海马各区神经元形态结构的影响。方法选择微管相关蛋白(MAP2)和神经丝(NF)作为正常神经元结构的标识物,利用免疫组织化学法和Western blot技术观察REM睡眠剥夺1、3、5、7 d4个时间点大鼠皮质及海马MAP2和NF表达的时空变化规律。同时运用电镜技术观察睡眠剥夺后神经元超微结构的变化。我们的实验是用改良的多平台睡眠剥夺模型进行REM睡眠剥夺,结合免疫组织化学染色技术和蛋白质电泳以及电镜超微结构分析。结果REM睡眠剥夺后5d大鼠皮质、海马CA1及齿状回神经元结构蛋白MAP2和NF表达较对照组明显减少(P〈0.05);电镜神经元核仁偏位,胞质中出现少量肿胀的线粒体和内质网;部分神经轴突的髓鞘溶解与浓集。环境对照组、REM睡眠剥夺5d和7d组,皮质中超微结构改变的神经元所占比例分别为1.2%、3.6%和5.8%。结论REM睡眠剥夺能够导致大鼠脑内神经元的超微结构发生异常变化。  相似文献   
25.
本文报告了1990年5月以来脑干区大型、复杂占位病变15例.其中,位于脑干内3例,脚间窝2例,岩尖部4例,全岩骨区1例,全斜坡区2例,第四脑室内3例.本组采用以扩大了的岩骨入路为主的联合入路,行肿瘤全切除8例,次全切除5例.2例仅作了活检加减压术.除1例死亡外,均恢复良好.本文结合文献,对脑干区手术入路进行了讨论.  相似文献   
26.
The amygdala is considered to be a critical neural substrate underlying the formation of stimulus-reward associations, and is known to receive substantial innervation from dopaminergic neurons located within the ventral mesencephalon. However, relat- ively little is known about the function of the mesoamygdaloid dopamine projection in stimulus-reward learning. Recently, we have found post-session intra-amygdala microinjections of d-amphetamine to enhance appetitive Pavlovian conditioning as assessed in a discriminative approach task. In the present study, we have examined the effects of dopamine receptor agonists possessing relative selectivity for the D1, D2 and D3 receptor subtypes in order to examine more fully the role of the mesoamygdaloid dopamine projection in stimulus-reward learning. Thus, subjects were trained to associate an initially neutral stimulus (CS+) with 10% sucrose reward (US). A second, control stimulus (CS) was also presented but never paired with sucrose reward. In order to measure specifically the conditioned response to CS+/CS presentation, responding during CS and US presentations was measured separately. Immediately following each training session, subjects received bilateral intra-amygdala infusion of 0.1, 1 or 10 nmol/side of SKF-38393, quinpirole or 7-OH-DPAT. Infusions of SKF-38393 or quinpirole were without effect on CS+ approach. However, post-session intra-amygdala infusions of 7-OH-DPAT enhanced selectively CS+ approach in a dose-dependent fashion. No dose of any drug affected CSapproach, US behaviours, or measures of extraneous behaviour. Subsequent acquisition of a novel conditioned instrumental response was also unaffected. Thus, the present data indicate a selective involvement of the D3 dopamine receptor subtype in the modulation of stimulus-reward learning by the mesoamygdaloid dopamine projection. Received: 12 December 1996 / Final version: 9 April 1997  相似文献   
27.
Background: Laparoscopic stapling was found to be a viable option for attaching epimysial electrodes onto the abdominal surface of the diaphragm. Stapling was preferable to suturing due to its simplicity and speed. Methods: Of the two staplers tested in this study, the Ethicon Endopath was preferred over the Autosuture Endo Hernia because the staples did not penetrate the diaphragm when an electrode tab thickness greater than 0.75 mm was used. Results: The thickness of the electrode tab was an important factor in determining staple penetration but large variation in penetration depth indicated that other factors may also play a role. An electrode tab thickness of 1.0–1.25 mm was suggested to minimize the risk of diaphragm perforation. Conclusions: The histological reaction to staples implanted up to 14 months was unremarkable, reflecting the safety of laparoscopic staples for permanently anchoring electrodes on the diaphragm. Received: 2 April 1996/Accepted: 12 June 1996  相似文献   
28.
Summary Surgery for highly placed basilar bifurcation aneurysms is one of the most difficult operations in neurosurgery. Specific surgical techniques have been developed including the temporopolar, zygomatic, transzygomatic subtemporal, transclinoid trans-sellar transcavernous, and trans third ventricular approaches. The authors present some technical advances which have been developed for the transcristagalli translamina terminalis approach for the treatment of this aneurysm.  相似文献   
29.
扩大经蝶入路进入海绵窦内侧腔的应用显微解剖   总被引:1,自引:0,他引:1  
目的为临床开展扩大经蝶入路进入海绵窦内侧腔手术提供解剖学依据。方法用50例成人头颅标本.在显微镜下对蝶窦外侧壁、蝶鞍、海绵窦及周围结构进行解剖学观察并测量。模拟扩大经蝶入路磨除海绵窦腹侧骨质,切开海绵窦内侧壁,显露海绵窦内侧腔。结果颈内动脉(ICA)明显隆起于蝶窦侧壁的占58%,蝶窦内隆起呈管型占3%。鞍底硬膜分为2层,海绵窦内侧壁的上部南垂体硬膜构成,无骨性结构支撑;下部由骨周硬膜构成,有蝶窦侧壁骨质支撑。两侧海绵窦内侧壁的距离为(14.8±2.7)mm。海绵窦内侧腔位于C4段ICA与垂体之间,腔内为丰富的静脉丛,最宽可达7mm,但常因ICA扭曲而闭塞。无颅神经穿越海绵窦内侧腔,ICA是扩大经蝶入路探查海绵窦遇到的第一个主要结构。结论扩大经蝶入路进入海绵窦内侧腔是安全可行的。  相似文献   
30.
The acromioclavicular joint is a potential source of pain in the shoulder. There are a variety of disorders that can affect this joint, including distal clavicle osteolysis, posttraumatic arthritis, osteoarthritis, and rheumatoid arthritis. Nonoperative treatment for this condition with nonsteroidal medication and activity modification can alleviate the pain. When conservative treatment is exhausted, surgical resection of the distal clavicle is often necessary. Arthroscopic resection of the distal clavicle preserves the acromioclavicular ligaments to prevent postoperative distal clavicle instability. The procedure is performed in either the beach chair or lateral position and requires the use of a shaver, electrocautery, and a burr for soft tissue and debridement and bone resection.  相似文献   
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