首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 0 毫秒
1.
支气管镜在呼吸系统疾病的诊治中有着非常广泛的应用,也是作为呼吸专科医师所必须掌握的一项临床技能。但是在对该项技术熟练之前,不能允许在病人身体直接操作,这样对呼吸专科医师的临床培训造成了较大困难。近年来,我院采用了美国模拟电子内镜教学系统进行培训,取得了满意的效果。通过该系统的训练,培训学员能对支气管镜的操作流程、操作技巧和手法,镜下气管,各叶、段支气管走行和解剖形态,病变的定位和镜下形态,以及如何对病变进行活检、支气管灌洗和出现并发症时怎样处理等,均有较为深刻的体会,并可获得多次反复练习的机会,培训所需时间也明显缩短。  相似文献   

2.
Summary In Drosophila melanogaster a partial loss of ribosomal genes leads to the bobbed phenotype. Magnification is a heritable increase in rDNA that may occur in males carrying a deleted X chromosome with a strong bobbed phenotype. The restriction patterns of X chromosome total rDNA, insertions and spacers from magnified bobbed strains were compared with those of the original bobbed mutations. It was found that magnification modifies restriction patterns and differentially affects gene types, increasing specific genes lacking insertions (INS-). Increases in copy number of genes with type I insertions are generally lower than the total number of INS- genes, while type II insertion genes are not perceptibly increased. The recovery of homogeneous progeny from a single premagnified male indicates that the magnification event might take place and become stable very early in the germ line, arguing against magnification being due to extrachromosomal amplification. Additionally, some gene types increase 3.5-fold while others are eliminated, indicating that they could not result from a single unequal cross-over. These results are in good agreement with the existence of partial clustering of rDNA genes according to type, and suggest that magnification could result from local amplification of genes.  相似文献   

3.
目的:探讨放大染色内镜对结节性胃炎、胃粘膜相关组织淋巴瘤诊断的可行性。方法:选择哈尔滨医科大学第四临床医学院2007年5月~2010年7月诊断的结节性胃炎、疑诊胃粘膜相关组织淋巴瘤患者,观察临床、内镜、病理表现、幽门螺杆菌感染情况和根除治疗的效果。并应用日本FUJINONEG-590ZW型放大内镜对患者进行检查,观察根除幽门螺杆菌前后结节性胃炎、胃粘膜相关组织淋巴瘤的改变。结果:纳入分析的100例成人患者,男25例,女75例,年龄19-68岁,平均年龄39.2岁。主要临床表现为上腹痛和消化不良症状。内镜下表现为胃窦部为主,可扩展至胃体部的色泽均匀的结节样或颗粒样改变。病理检查显示胃窦部活检标本中有伴生发中心的淋巴滤泡增生。所有患者均有幽门螺杆菌感染,经根除治疗后,症状缓解率达92.0%。结论:结节性胃炎、胃粘膜相关组织淋巴瘤发生与幽门螺杆菌感染相关,放大染色内镜对结节性胃炎有诊断意义。  相似文献   

4.
    
In this study the generalized Modulation Transfer Function (GMTF) and the geometric sharpness (Sgeo) were used (i) to study the effects of various focal spot sizes (0.04 mm–0.3 mm), x-ray intensity distributions (Gaussian and double Gaussian), breast thicknesses (2–7 cm) and magnifications M (1.0–2.0) on the spatial resolution of an a-Se digital mammography system, (ii) to identify suitable focal spots for magnification mammography and (iii) derive optimum magnifications. For the calculation of GMTF the required components were: focal spot MTF, obtained from theory, detector MTF, scatter MTF and scatter fraction obtained from Monte Carlo simulations. The results showed that focal spots with sizes up to 0.18 mm are suitable for magnification mammography offering a GMTF which is >50% and >20% at the respective object frequencies of 6.5 mm−1 and 9 mm−1. Focal spots with sizes < 0.16 mm and Gaussian. intensity distribution, or sizes ≤ 0.1 mm and double Gaussian, offer a system resolution which improves or does not deteriorate with magnification for most object frequencies. For larger focal spots, i.e. 0.16–0.18 mm for a Gaussian and 0.12–0.18 mm for a double Gaussian. intensity distribution, optimum magnifications exist which depend on the object frequency and breast thickness. System resolution (in terms of Sgeo) is maximized at M = 1.8–2.0 (all breast thicknesses) for Gaussian intensity distribution, and at M = 1.4–1.6 (breast thicknesses ≤ 4 cm) and M = 1.6–1.8 (thicker breasts) for double Gaussian.  相似文献   

5.
采用He—Ne激光(632.8nm辐照了天使鱼(Pterophyllum eimeki)的发育阶段的胚胎,观察和分析激光辐照对胚胎发育的致变影响和各发育阶段胚胎对激光的受激反应。对受精卵、囊胚期、原肠期和神经胚期的胚胎进行照射,均引起各期胚胎的畸变,这些畸变大多数是初孵仔鱼的头部、尾部、胸腔和背脊的变形。实验结果表明,天使鱼各个发育阶段的胚胎畸变率随着激光辐照剂量的改变而发生变化。  相似文献   

6.
激光辐照鱼类胚胎导致畸变   总被引:2,自引:0,他引:2  
红激光(He—Ne,632.8nm)辐照金鱼(Carassius aurafus)受精卵和怀胎孔雀鱼(Poecilia reticulata),导致两种鱼胚胎畸变。金鱼胚胎在某一发自阶段的畸变率随辐照剂量的增加而提高;在同一剂量辐照下,不同发育期的胚胎畸变率各异,胚胎发育初期畸变率最高,此后随胚胎发育过程畸变率下降。经He—Ne激光辐照的孔雀亲鱼也能生产畸形仔鱼。在实验中还比较了红激光(632.8nm)和紫激光(N_2337.1nm)辐照金龟卵致变效果。  相似文献   

7.
黄伯湛  冯洁贞 《激光生物学报》1997,6(1):998-1000,1005
He-NeYAG和CO2激光对花生L1代幼苗期有刺激生长的作用,CO2激光对花生L1代的株高有较明显的抑制作用,CO2,He-Ne和YAG激光对花生L1代植株的总果数,饱果数有一定的增多作用,且前者最明显,但N2激光对花生L1代植株的总果数,饱果数均有明显的减少作用;He-NeYAG,N2和CO2激光均能诱发药生根尖细胞染色体畸变,且畸变率随辐照剂量的增大而上升,以上四种激光所诱发发生的变异性状是  相似文献   

8.
    
IntroductionThe ablation of ventricular tachycardia, including premature ventricular contractions, is an approved, albeit infrequent procedure in pediatric patients. Data are scarce regarding the outcomes of this procedure. The purpose of this study was to share a high-volume center experience and patient outcomes for catheter ablation of ventricular ectopy and ventricular tachycardia in pediatric population.MethodsData were retrieved from the institutional data bank. Outcomes over time were evaluated, and procedural details were compared.ResultsA total of 116 procedures were performed on 102 pediatric patients between July 2009 and May 2021 at the Rajaie Cardiovascular Medical and Research Center in Tehran, Iran. Ablation was not performed in 4 procedures (3.4%) due to high-risk substrates. Of the remaining 112 ablations performed, 99 (88.4%) were successful. However, one patient died due to a coronary complication. There were no significant differences observed in early ablation results based on patients' age, sex, cardiac anatomy, or ablation substrates (P > 0.05). Follow-up records were available for 80 procedures, and 13 (16.3%) of those experienced recurrence. During long-term follow-up, none of the variables mentioned above were statistically different between patients with or without arrhythmia recurrence.ConclusionThe overall success rate of pediatric ventricular arrhythmia ablation is favorable. We found no significant predictor for the procedural success rate concerning acute and late outcomes. Larger multicenter studies are needed to elucidate the predictors and outcomes of the procedure.  相似文献   

9.
Sputum cytology is regarded by many clinicians as a noninvasive, cheap and simple test for the diagnosis of bronchogenic carcinoma. Since the introduction of fibre-optic bronchoscopy and more easily obtained bronchial biopsies reliance on sputum cytology has diminished. However, in Edinburgh it was perceived that sputum samples were still being sent as well as, rather than instead of, bronchoscopic specimens. This retrospective study was undertaken to determine whether or not cytological examination of sputum is an efficient and sensitive test in the investigation of patients with suspected bronchogenic carcinoma. It demonstrated that the Lothian University Hospitals NHS Trust Pathology Directorate receives many sputa from departments not specializing in respiratory disease when there is no indication for the test. In addition, we have shown that the absolute sensitivity of the test is only 5% and that when there is a strong clinical suspicion of bronchogenic carcinoma the results of sputum cytology do not play a significant role in the management of the patient. We recommend that sputum cytology is restricted to those patients under the care of Respiratory Units in whom bronchoscopy is inappropriate or unsuccessful.  相似文献   

10.
    
An open-source Python library EMDA for cryo-EM map and model manipulation is presented with a specific focus on validation. The use of several functionalities in the library is presented through several examples. The utility of local correlation as a metric for identifying map-model differences and unmodeled regions in maps, and how it is used as a metric of map-model validation is demonstrated. The mapping of local correlation to individual atoms, and its use to draw insights on local signal variations are discussed. EMDA’s likelihood-based map overlay is demonstrated by carrying out a superposition of two domains in two related structures. The overlay is carried out first to bring both maps into the same coordinate frame and then to estimate the relative movement of domains. Finally, the map magnification refinement in EMDA is presented with an example to highlight the importance of adjusting the map magnification in structural comparison studies.  相似文献   

11.
在大量野外调查的基础上,对南水北调中线干渠沿线植物区系特征和主要植被类型进行了系统的研究分析。结果表明,沿线典型植被类型的主要组成种类约有360种,隶属于106科252属;植物区系主要属温带性质,具有亚热带一热带区系的过渡性质;特有性程度非常低,仅有1科(银杏科)4属,即地构叶属(Speranskia)、蛇葡萄属(Ampelopsis)、水杉属(Metasequoia)、银杏属(Ginkgo)为我国特有;没有国家和地方重点保护的植物物种分布。依据Flexible Beta Clustering分类,干渠沿线主要植被类型可以划分为5个植被型和65个群丛,乔、灌层组成结构非常单一,草本层较为发达。研究结果对工程沿线的植被保护和恢复工作具有重要意义。  相似文献   

12.
    
We have recently established a rhesus monkey model of chronic Pseudomonas aeruginosa (PA) endobronchitis by bronchoscopic instillation of PA-embedded agar beads. All experimental animals developed chronic neutrophilic endobronchitis similar to chronic PA endobronchitis in cystic fibrosis (CF). Histopathologic studies further confirmed similarities to chronic PA endobronchitis in CF, including marked peribronchial inflammation, epithelial damage, presence of degraded cilia and ciliary abnormalities, appearance of PA bacterial clusters, mucosal hyperplasia, goblet cell hypertrophy/hypersecretion, airway obstruction, alveolar abnormalities, bronchiectasis, and fibrosis.  相似文献   

13.
This paper presents the results of an extended evaluation programme designed to test the effectiveness of text-based flexible learning as a replacement to 30 – 50% of the lectures in certain modules in conventional undergraduate courses within the School of Life Sciences at Napier University. For examinations in which students answered both types of question, marks for questions based on topics taught by flexible learning were equivalent to marks for questions based on topics taught by conventional teaching methods. Marks for examinations in which at least 50% of the answers were based on topics taught by flexible learning were equivalent to marks for examinations in which questions were based on topics taught by conventional teaching methods. Rates of achievement of a mark of 40% or more at first attempt for examinations in which at least 50% of the answers were based on topics taught by flexible learning were significantly better than rates of achievement of a mark of 40% or more at first attempt for questions based on topics taught by conventional teaching methods. Students gave positive feedback on flexible learning, both verbally and by questionnaire, and showed highly significant bias in favour of topics taught by flexible learning in their choice of questions in examinations. The flexible learning programme studied here has satisfied the various quality assurance criteria in place within the University throughout the time that it has been in operation. The evaluation has demonstrated that the textbased flexible learning programme studied here was an effective alternative to lectures.  相似文献   

14.
On the interpretability of ordination diagrams   总被引:1,自引:0,他引:1  
  相似文献   

15.
16.
    
Abstract. Standardization by norms of sample position vectors as well as by sample totals has been used frequently in vegetation ecology. Both standardizations are only special cases of the Generalized Standardization Procedure (GSP) described in this paper. The general procedure allows a wide choice of data transformations simply by varying values of a single standardization parameter. Principal Components Analysis (PCA) often involutes opposite ends of a coenospace, producing results that may be difficult to interpret. Experiments with simulated as well as field data sets revealed that involuted gradients can be unfolded if GSP is applied prior to PCA. Compared to Correspondence Analysis, GSP-PCA was superior in recovering the structure of analysed coenoclines.  相似文献   

17.
18.
    
Given Wolpoff's (1981) dimensions for lambda-bregma and biparietal breadth, it was possible to reconstruct a new version of the O.H.7 hominid parietals. The constraints of the anatomical features of the original parietal fragments plus Wolpoff's constraints from his own reconstruction, permit testing his claims as a hypothesis. By comparing the resulting distortion of Wolpoff's proposed reconstruction with that of the original reconstruction by Tobias, it is clear that the latter's is far superior to the former's, and that the cranial capacity of O.H.7 of roughly 700 ml is most probable.  相似文献   

19.
目的探讨纤支镜检查技术对菌阴性肺结核的诊断价值。方法通过回顾性分析153例痰涂片、痰培养和PCR分析均为结核杆菌阴性疑诊为肺结核最终确诊为肺结核的患者病例资料。观察肺结核病灶在纤支镜下的表现,并于镜下行组织活检、刷检、组织盲检,支气管肺泡灌洗液涂片及PCR检查和痰结核分枝杆菌涂片检查。结果回顾性分析发现肺结核纤支镜下改变主要为粘膜充血肿胀(23.5%)、粘膜溃疡糜烂(19.6%)、粘膜表面灰白色苔状物或豆腐渣样物质覆盖(15.7%)和支气管瘢痕或狭窄(13.1%)。纤支镜下组织活检、刷检、组织盲检,支气管肺泡灌洗液涂片及PCR检查和痰结核分枝杆菌涂片检查,诊断为肺结核的患者占最终明确诊断为肺结核的百分比分别为41.2%(63/153),47.1%(72/153),11.1%(17/153),56.9%(87/153),55.6%(85/153)和32.0%(49/153)。结论菌阴性肺结核镜下改变多样无特征性,纤支镜检查技术对菌阴性肺结核的明确诊断具有重要价值,多种纤支镜技术联合能够明显提高菌阴性肺结核的诊断率。  相似文献   

20.
目的:探讨高仿真模拟支气管镜模拟技术在呼吸科专科医师支气管镜操作训练中的作用.方法:对20名呼吸科医生(支气管镜检查术的初学者)作为观察对象,采用美国生产的Simbionix GI Mentor Simulator高仿真模拟支气管镜操作系统进行培训.由2名熟练进行支气管镜检查术的呼吸科医生进行指导,比较培训前后在高仿真模拟支气管镜操作的速度、灵活性和准确性方面差异.结果:20名初学者均完成了支气管镜的操作培训.在模拟训练后,操作的灵活性、准确性和速度都明显提高.与训练前相比视野清晰可见时间由(30.0±2.0)%增加到(75.0±5.0)%:段支气管检查到达由(74.0±5.1)%提高到(89.3±4.0)%;通过咽喉及声门时间由(00.01.28±00.00.54)h缩短到(00.00.36± 00.00.09)h,操作用时由(00.07.27± 00.01.23)h缩短到(00.06.24± 00.00.54)h.误入食道次数由(6.0±2.0)缩短到(2.0±0.5),培训前机器给予自动评分为(30.8±6.6)分,培训后(70.8±6.6)分.结论:高仿真模拟支气管镜在初学气管镜呼吸专科医师培训中起到重要的作用.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号