振幅型光栅法人眼调制传递函数测定的理论分析

目的:介绍测量视网膜调制传递函数的方法和光学原理,验证振幅型正弦光栅加零级空间滤波的方法测量视网膜调制传递函数使测量仪器小型化的可行性。方法:目前测量仪器中获得两相干点光源主要是使用平行板法、双道威棱镜法和光栅法3种,从理论上分析比较3种方法的优劣性,并重点分析矩形光栅、振幅型正弦光栅的各级衍射光强分布特点。结果:①平板法和双道威棱镜法可获得两相干点光源,也是在视网膜调制传递函数测量仪中应用比较成熟的技术,其光学原理简单,获得相干点光源的相干性良好,光强稳定。另外,使用双道威棱镜法时,可以用电位带动反射镜的移动来控制两点光源的间距,易于装置的智能化控制,但所设计的仪器外观尺寸较大,移动性较差,不利于测量装置的手持式和小型化发展。②矩形光栅法可以实现仪器的小型化,但由于矩形光栅的衍射图样是单缝衍射图样与多光束干涉图样相互调制的结果,即衍射光强的多光束干涉条纹干扰测量结果。③振幅型正弦光栅的透过率函数可以实现0￣1,以余弦波形式对入射光波产生振幅调制,且衍射光强只有三级谱线(0级和±1级),且±1级谱线的光强分布具有对称性,只要进行零级空间滤波,就可以得到作为视标调制度的两个点光源。结论:振幅型正弦光栅加零级空间滤波可以获得相干性良好相干点光源,并且可以实现测量仪器的小型化。     

脊髓全横断大鼠神经生长因子和脑源性神经营养因子表达及三七皂苷的干预效应

目的:神经生长因子和脑源性神经营养因子同属神经营养素家族,在神经系统发育及维持正常神经元功能中有重要作用。实验拟证实脊髓全横断损伤三七皂苷对大鼠神经生长因子及脑源性神经营养因子蛋白水平的表达变化产生了影响。方法:实验于2005-06/09在昆明医学院神经科学研究所完成。①实验材料:清洁级健康雌性SD大鼠72只,质量(200±20)g;三七皂苷由云南植物药业提供。②分组及实验过程:大鼠被随机分为4组:假手术组、单纯脊髓全横断损伤组、脊髓全横断损伤 生理盐水(0.5mL/次)组、脊髓全横断损伤 三七皂苷(100mg/kg/次)组,每组18只。于T10水平横断大鼠脊髓,假手术组仅剪开硬脊膜而不损伤脊髓。后2组于术后30min,4,24,48,72h腹腔注射给药各1次。③实验评估:各组于术后3,7及21d分别取6只大鼠L1～2段脊髓制作冰冻切片,采用免疫组织化学ABC法染色。观察并计数脊髓腹角神经生长因子、脑源性神经营养因子蛋白的表达变化;常规苏木精伊红染色观察脊髓的组织病理变化。结果:72只大鼠全部进入结果分析:①脊髓全横断损伤后脊髓出现明显的神经变性坏死、炎性浸润等病理变化,三七皂苷可减轻这些变化。②神经生长因子蛋白主要分布于灰质神经元胞浆及胶质细胞胞核中。在正常脊髓有少量表达,脊髓损伤后7d表达明显升高,直到伤后21d仍高于假手术组(P<0.05);三七皂苷可明显促进其表达,伤后3,7d均明显高于其他各组(P<0.05),在21d时下降但仍高于假手术组(P<0.05)。③脑源性神经营养因子蛋白主要分布于腹角的运动神经元胞浆中,胶质细胞未见着色。在正常脊髓有少量表达,脊髓损伤后7d表达明显升高(P<0.05),伤后21d已下降,同假手术组相比差异无显著性(P>0.05);三七皂苷可明显促进其表达,伤后3,7,21d均明显高于所有对照组(P<0.05)。结论:三七皂苷可减轻脊髓横断性损伤后继发损害,增加神经生长因子、脑源性神经营养因子表达量及提前神经生长因子、脑源性神经营养因子表达时间,提示其可以促进脊髓损伤早期修复。     

Second‐look endoscopy with thermal coagulation or injections for peptic ulcer bleeding: A meta‐analysis

Background and Aims: In the management of peptic ulcer bleeding, the benefits of second‐look endoscopic treatment with thermal coagulation or injections in controlling recurrent bleeding is unsure. This study set out to compare efficacy of routine second‐look endoscopy with treatment using either thermal coagulation or injections versus single endoscopy by pooling data from published work. Methods: Full publications in the English‐language published work as well as abstracts in major international conferences were searched over the past 10 years, and six trials fulfilling the search criteria were found. Outcome measurements included: (i) recurrent bleeding; (ii) requirement of surgical intervention; and (iii) mortality. We examined heterogeneity of trials and pooled the effects by meta‐analysis. The quality of studies was graded according to the prospective randomization, methods of patient allocation, the list of exclusion criteria, outcome definitions and the predefined salvage procedures for uncontrolled bleeding. Results: Among 998 patients recruited in these five randomized trials, 119 received routine second‐look endoscopy with thermal coagulation, and 374 received second‐look with endoscopic injection and 505 had single endoscopic therapy. Less recurrent bleeding was reported after thermal coagulation (4.2%) than single endoscopy (15.7%) (relative risk [RR] = 0.29; 95% confidence interval [CI] = 0.11–0.73), but no reduction was reported for the requirement of surgical intervention and all‐cause mortality. Injection therapy did not reduce re‐bleeding (17.6%) when compared to single endoscopy (20.8%; RR = 0.85; 95% CI = 0.63–1.14), requirement for surgery and mortality. Conclusion: Routine second‐look endoscopy with thermal coagulation, but not injection therapy, reduced recurrent peptic ulcer bleeding. There is no proven benefit in reducing surgical intervention and overall mortality.     

Pharmacologic treatment of the irritable bowel syndrome: a systematic review of randomized, controlled trials

PURPOSE: To evaluate the efficacy of pharmacologic agents for the irritable bowel syndrome. DATA SOURCES: Electronic literature search of MEDLINE (1966 to 1999), EMBASE (1980 to 1999), PsycINFO (1967 to 1999), and the Cochrane controlled trials registry and a manual search of references from bibliographies of identified articles. STUDY SELECTION: Randomized, double-blind, placebo-controlled, parallel, or crossover trials of a pharmacologic intervention for adult patients that reported outcomes of improvement in global or irritable bowel-specific symptoms. DATA EXTRACTION: Qualitative and quantitative data reported on study groups, interventions, treatment outcomes, and trial methodologic characteristics. DATA SYNTHESIS: 70 studies met the inclusion criteria. The most common medication classes were smooth-muscle relaxants (16 trials), bulking agents (13 trials), prokinetic agents (6 trials), psychotropic agents (7 trials), and loperamide (4 trials). The strongest evidence for efficacy was shown for smooth-muscle relaxants in patients with abdominal pain as the predominant symptom. Loperamide seems to reduce diarrhea but does not relieve abdominal pain. Although psychotropic agents were shown to produce global improvement, the evidence is based on a small number of studies of suboptimal quality. Psychotropic drugs, 5-hydroxytryptamine (5-HT)-receptor antagonists, peppermint oil, and Chinese herbal medicine require further study. CONCLUSIONS: Smooth-muscle relaxants are beneficial when abdominal pain is the predominant symptom. In contrast, the efficacy of bulking agents has not been established. Loperamide is effective for diarrhea. Evidence for use of psychotropic agents is inconclusive; more high-quality trials of longer duration are needed. Evidence for the efficacy of 5-HT-receptor antagonists seems favorable, although more studies are needed.     

Anti-neutrophil cytoplasmic antibodies in Japanese children with ulcerative colitis

Objective: To investigate the diagnostic value of anti-neutrophil cytoplasmic antibodies (ANCA) in the diagnosis of ulcerative colitis (UC) in Japanese children.
Methodology Serum samples from 23 children with UC (17 Japanese, 6 non-Japanese), 27 children with Crohn's disease (CD) (10 Japanese, 17 non-Japanese), 10 children with other diarrhoeal diseases, and 33 normal, healthy adult volunteers were assayed for ANCA using an indirect immunofluorescence technique.
Results ANCA were detected in 6/17 (35%) UC patients and 0/10 (0%) CD patients in Japanese children, and in 3/6 (50%) UC patients and 3/17 (18%) CD patients in non-Japanese children. The difference in prevalence between Japanese and non-Japanese children with UC was not statistically significant ( P >0.05). ANCA were not found in other diarrhoeal patients and volunteers.
Conclusions Although ANCA have been reported to be useful in the diagnosis of UC in adults, they may be of limited use in Japanese children. This might reflect the heterogeneity of UC.     

A comparison of traditional and Rasch cut points for assessing clinically important change in health-related quality of life among patients with asthma

Background Patient-perceived change in health-related quality of life (HRQoL) domains has often been classified using a 15-point patient transition rating scale. However, traditional change levels of trivial ( − 1, 0, or 1), minimal (2, 3 or − 2, − 3), moderate (4, 5 or − 4, − 5) and large (6, 7 or − 6, − 7) on this scale have been arbitrarily defined and originally assumed that change related to an improvement was the same as that for a decline. Objective To compare traditional and Rasch partial credit model-derived cut points and the mean changes for each change categorization when assessing clinically important change in asthma-specific HRQoL. Methods Our sample included 396 asthmatic outpatients who completed bimonthly telephone interviews on the Asthma Quality of Life Questionnaire and transition rating items over 1 year of participation. We employed item response theory in a novel approach to identify cut points on domain-specific HRQoL change data and transition ratings. After determining natural cut points for minimal, moderate, and large differences on the transition rating anchor, we calculated mean changes under change categorizations for both improvements and declines for the two transition rating classification approaches. Results Although traditional and Rasch categorizations for small, moderate, and large changes slightly differed and displayed a lack of symmetry between improvements and declines, nearly all mean changes between classification approaches were comparable. Conclusions In this study, traditional transition rating cut points remain suitable to assess HRQoL clinical significance in outpatients with asthma. An earlier version of this paper was presented at the International Society for Quality of Life Research Symposium, June 29, 2004, in Boston, MA and at the International Society for Quality of Life Annual Meeting, October 20, 2005, in San Francisco, CA.     

The role of gluten, milk, and other dietary proteins in chronic or intermittent dyspepsia

In twenty-seven patients with chronic or intermittent dyspepsia raised levels of the gamma-M-globulin and of the α₁- and of the α₂-globulin were encountered. Malabsorption, present in about three-quarters of the cases, was usually mild. Various degrees of villous abnormalities were seen but no flat mucosa. Eight patients also had dermatitis. During dietary treatment with the elimination of gluten, milk, or other food elements the dyspepsia and the malabsorption subsided in all but two, and the dermatitis in all but one. In nearly all the investigated cases the raised levels of the gamma-M-globulin and of the α₁- and of the α₂-globulin decreased. During challenge feeding with the offending food the dyspepsia and the dermatitis reappeared. Also the faecal fat excretion increased again, and a rise was noticed in the α₁- and in the α₂-globulins and in the gamma-M-globulins. The findings suggest that gluten, milk and other dietary proteins may play a role in some chronic dyspepsias by exerting an antigenic stimulus on the small intestinal mucosa, and thus inducing a state of hypersensitivity towards these foods. The clinical and laboratory findings favour the view that the condition is different from coeliac disease