胶原海绵复合新生大鼠原代心肌细胞构建工程化心肌组织

目的:探索以胶原海绵为支架、新生大鼠原代心肌细胞为种子细胞,于体外构建工程化心肌组织的方法。方法:实验于2005-12/2006-11在解放军第四军医大学西京医院心内科实验室完成。Ⅰ型胶原海绵剪切成方形片状(2.0cm×1.4cm×0.2cm),经60Co照射消毒,于DMEM培养液中水化1h左右。另取1d龄SD大鼠心脏,剪成小碎块,然后用2.5g/L胰蛋白酶于37℃中消化,吸取上清至含胎牛血清的DMEM中,重复消化四五次,用差速贴壁法除去大部分成纤维细胞,将细胞沉淀用DMEM培养液以2×109L-1的密度悬浮备用。将上述的心肌细胞悬液1mL缓慢滴注于玻璃模型中的胶原海绵上,然后置于细胞培养中培养。肉眼及显微镜主要观察工程化心肌组织在培养期间的自发收缩情况,包括收缩的部位、强度、频率、一致性以及收缩随时间变化的情况。苏木精-伊红染色观察工程化心肌组织内胶原纤维的变化,细胞形态,胞核的形状及细胞之间的连接。免疫组织化学染色和透射电镜观察工程化心肌组织片的形态和功能。结果:①细胞接种于胶原海绵上1d后,细胞/胶原复合物的凝胶化过程基本完毕,体积保持恒定,维持至培养结束,第3天细胞/胶原复合物局部出现点片状自发收缩,第5天整个细胞/胶原复合物出现同步化自发收缩,收缩频率61～199次/min。2周后37.5%的工程化心肌组织的自发收缩活动减弱,但75%的工程化心肌组织的自发收缩活动持续至培养结束。②苏木精-伊红染色、免疫组织化学染色和透射电子显微镜显示,工程化心肌组织内细胞间连接广泛存在,细胞多呈纵向分布,胞核呈长圆形,胞浆内α-肌节肌动蛋白阳性,胞内肌原纤维排列整齐,可见到心肌特异性的肌小节结构和Z线,多数细胞具有分化的心肌细胞表型。结论:用新生大鼠原代心肌细胞为种子细胞、以Ⅰ型胶原海绵为支架材料,构建出的工程化心肌组织,于体外可长时间持续自发收缩,该细胞/胶原复合物的形态结构与生理功能均类似于成熟大鼠心肌组织。     

False-negative and False-positive Errors in Abdominal Pain Evaluation Failure to Diagnose Acute Appendicitis and Unnecessary Surgery

OBJECTIVES: To test the hypothesis that physician errors (failure to diagnose appendicitis at initial evaluation) correlate with adverse outcome. The authors also postulated that physician errors would correlate with delays in surgery, delays in surgery would correlate with adverse outcomes, and physician errors would occur on patients with atypical presentations. METHODS: This was a retrospective two-arm observational cohort study at 12 acute care hospitals: 1) consecutive patients who had an appendectomy for appendicitis and 2) consecutive emergency department abdominal pain patients. Outcome measures were adverse events (perforation, abscess) and physician diagnostic performance (false-positive decisions, false-negative decisions). RESULTS: The appendectomy arm of the study included 1, 026 patients with 110 (10.5%) false-positive decisions (range by hospital 4.7% to 19.5%). Of the 916 patients with appendicitis, 170 (18.6%) false-negative decisions were made (range by hospital 10.6% to 27.8%). Patients who had false-negative decisions had increased risks of perforation (r = 0.59, p = 0.058) and of abscess formation (r = 0.81, p = 0.002). For admitted patients, when the inhospital delay before surgery was >20 hours, the risk of perforation was increased [2.9 odds ratio (OR) 95% CI = 1.8 to 4.8]. The amount of delay from initial physician evaluation until surgery varied with physician diagnostic performance: 7.0 hours (95% CI = 6.7 to 7.4) if the initial physician made the diagnosis, 72.4 hours (95% CI = 51.2 to 93.7) if the initial office physician missed the diagnosis, and 63.1 hours (95% CI = 47.9 to 78.4) if the initial emergency physician missed the diagnosis. Patients whose diagnosis was initially missed by the physician had fewer signs and symptoms of appendicitis than patients whose diagnosis was made initially [appendicitis score 2.0 (95% CI = 1.6 to 2.3) vs 6.5 (95% CI = 6.4 to 6.7)]. Older patients (>41 years old) had more false-negative decisions and a higher risk of perforation or abscess (3.5 OR 95% CI = 2.4 to 5.1). False-positive decisions were made for patients who had signs and symptoms similar to those of appendicitis patients [appendicitis score 5.7 (95% CI = 5.2 to 6.1) vs 6.5 (95% CI = 6.4 to 6.7)]. Female patients had an increased risk of false-positive surgery (2.3 OR 95% CI = 1.5 to 3.4). The abdominal pain arm of the study included 1,118 consecutive patients submitted by eight hospitals, with 44 patients having appendicitis. Hospitals with observation units compared with hospitals without observation units had a higher "rule out appendicitis" evaluation rate [33.7% (95% CI = 27 to 38) vs 24.7% (95% CI = 23 to 27)] and a similar hospital admission rate (27.6% vs 24.7%, p = NS). There was a lower miss-diagnosis rate (15.1% vs 19.4%, p = NS power 0.02), lower perforation rate (19.0% vs 20.6%, p = NS power 0.05), and lower abscess rate (5.6% vs 6.9%, p = NS power 0.06), but these did not reach statistical significance. CONCLUSIONS: Errors in physician diagnostic decisions correlated with patient clinical findings, i.e., the missed diagnoses were on appendicitis patients with few clinical findings and unnecessary surgeries were on non-appendicitis patients with clinical findings similar to those of patients with appendicitis. Adverse events (perforation, abscess formation) correlated with physician false-negative decisions.     

A fuzzy logic model for differential diagnosis of lower urinary tract dysfunctions

Lower urinary tract dysfunctions (LUTD) restrict quality of life, resulting in decreased work productivity and emotional well‐being. However, most people are not diagnosed because they do not seek medical treatment. In addition, some facilities do not adequately train health professionals in the evaluation, diagnosis and treatment of these conditions. The study's objective was to develop a decision support system modelled on fuzzy logic that defines LUTD using the terminology of the International Continence Society. This methodological study aimed to develop a model that uses the maximum–minimum composition (max–min) of fuzzy relations that can perform differential diagnoses of LUTD. The model was tested in 100 cases (50 men and 50 women), and the data were obtained from medical records containing the clinical data and results of urodynamic studies. All medical records were reviewed by a specialist in urology. The model was capable of determining a diagnosis in full (62%) or partial (36%) agreement with the medical report. Agreement between the model and the medical report was excellent (kappa = 0·98, p ? 0·001, CI = 0·88–1) or substantial (kappa = 0·53, p ? 0·001, CI = 0·45–0·60), considering overestimative accordance (where accordance is assumed when at least one diagnosis is equal) and underestimative accordance (where accordance is assumed when all diagnoses are equal), respectively. The proposed model based on the max–min composition of fuzzy relationships is very simple and performed well. However, more tests are recommended before the model is used as a decision support system.     

Multifocal pyomyositis: report of two cases

Pyomyositis is a primary infection of the striated muscles. We describe the clinical and imaging features of pyomyositis in two patients, one diabetic and the other immunocompetent. Treatment with incision, drainage and antibiotics was successful and resulted in full recovery. Increased awareness, especially in immuno‐competent patients, should lead to earlier diagnosis, correct treatment and a better outcome.     

Contribution of the Vertebral Posterior Elements in Anterior–Posterior DXA Spine Scans in Young Subjects

Because DXA is a projection technique, anterior–posterior (AP) measurements of the spine include the posterior elements and the vertebral body. This may be a disadvantage because the posterior elements likely contribute little to vertebral fracture resistance. This study used QCT to quantify the impact of the posterior elements in DXA AP spine measures. We examined 574 subjects (294 females and 280 males), age 6–25 yr, with DXA and QCT. QCT measures were calculated for the cancellous bone region and for the vertebral body including and excluding the posterior elements. DXA data were analyzed for the entire L₃ vertebra and for a 10‐mm slice corresponding to the QCT scan region. BMC and BMD were determined and compared using Pearson's correlation. The posterior elements accounted for 51.4 ± 4.2% of the total BMC, with a significant difference between males (49.9 ± 4.0%) and females (52.8 ± 3.9%, p < 0.001). This percentage increased with age in younger subjects of both sexes (p < 0.001) but was relatively consistent after age 17 for males and 16 for females (p > 0.10). DXA areal BMD and QCT volumetric BMD correlated strongly for the whole vertebra including the posterior elements (R = 0.83), with BMC measures showing a stronger relationship (R = 0.93). Relationships were weaker when excluding the posterior elements. We conclude that DXA BMC provides a measure of bone that is most consistent with QCT and that the contribution of the posterior elements is consistent in young subjects after sexual maturity.     

Brief report: quality of life is impaired in pediatric burn survivors with posttraumatic stress disorder

Objective This study assessed health-related quality of life(HRQOL) and posttraumatic stress disorder (PTSD) in pediatricburn survivors and examined associations between PTSD and HRQOL.Methods Forty-three burn survivors, ages 7–16 years, wereinterviewed at an average of 4.4 years after their accidentusing the Clinician-Administered PTSD Scale for Children andAdolescents and the TNO-AZL Child Quality of Life Questionnaire.Results Eight children (18.6%) met DSM-IV criteria for currentPTSD. While most dimensions of HRQOL were within normal limits,social functioning was impaired. Severity of PTSD was significantlyassociated with physical, cognitive, and emotional dimensionsof HRQOL. Children with PTSD reported an impaired overall HRQOLand limited physical (e.g., more bodily complaints) and emotionalfunctioning (e.g., more feelings of sadness). Conclusions Thisstudy provides tentative evidence for a considerably high prevalenceof PTSD in pediatric burn survivors and for a negative associationbetween PTSD and HRQOL.