Immunoperoxidase stains of ganglion cells and abnormal mucosal nerve proliferations in Hirschsprung's disease

Hirschsprung's disease is congenital aganglionosis of the distal colon. The affected bowel shows an abnormal proliferation of mucosal nerve fibers by acetylcholinesterase stains. We retrospectively reviewed biopsy specimens from patients with suspected and proven Hirschsprung's disease, performed immunoperoxidase stains for S-100 protein and neuron-specific enolase (NSE), and compared these results to routine histologic findings and acetylcholinesterase stains. Ganglion cells were demonstrated by immunoperoxidase in 63 of 69 specimens containing ganglion cells and in 1 specimen interpreted as aganglionic by hematoxylin-eosin staining. Increased numbers of nerve fibers in the muscularis mucosae and deep lamina propria by S-100 staining were detected in 8 of 8 specimens diagnostic for Hirschsprung's disease by hematoxylin-eosin and acetylcholinesterase stains and in 1 specimen diagnostic for colonic neuronal dysplasia (a disorder related to Hirschsprung's disease). Whereas 45 of 67 specimens from unaffected bowel showed a normal number and distribution of nerve fibers by S-100 staining, in 22 the pattern resembled that of Hirschsprung's disease. Specimens from affected colon also showed hypertrophied submucosal nerve trunks by S-100 stain (average nerve trunk thickness, 29.8 micron in affected bowel, 16.1 micron in unaffected segments--p less than 0.03). We conclude that NSE and S-100 stains are of value in demonstrating ganglion cells in suspected cases of Hirschsprung's disease and colonic neuronal dysplasia. The acetylcholinesterase stain is preferred over S-100 stain for detecting mucosal nerve proliferations in affected bowel. Submucosal nerve trunk thickness, although significantly different in affected and unaffected colon, is not of diagnostic value because of the wide variation in the measurements in the two groups.     

Differential susceptibility of human T(h)1 versus T(h) 2 cells to induction of anergy and apoptosis by ECDI/antigen-coupled antigen-presenting cells

Antigen-coupled antigen-presenting cells (APC) serve as potent tolerogens for inhibiting immune responses in vivo and in vitro, apparently by providing an antigen-specific signal through the TCR in the absence of co-stimulation. Although this approach has been well studied in rodents, little is known about its effects on human T cells. We evaluated the specificity and mechanisms of tolerization of human T cells in vitro using monocyte-enriched adherent cells that were pulsed with antigen and treated with the cross-linker, 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (ECDI). Autologous antigen-coupled APC selectively tolerized T cells of the T(h)1 but not T(h)2 lineage through a mechanism that involved both antigen-specific and antigen-non-specific elements. The tolerization process was dependent on the ECDI and antigen concentration, and the coupling time, and was reflected by initial up-regulation of CD25. However, upon re-stimulation with fresh APC and antigen, tolerized T(h)1 cells failed to proliferate or to produce T(h)1 cytokine message or secreted protein, had decreased expression of CD25, CD28 and B7 and increased expression of MHC class II molecules, and demonstrated an enhanced commitment to apoptosis. T(h)1 cell tolerization could be prevented by adding anti-CD28 antibody, IL-2 or untreated APC at the same time as the ECDI/antigen-coupled APC, or reversed by adding anti-CD28 antibody or IL-2 upon re-stimulation with fresh APC plus antigen. Thus, the tolerizing effect of ECDI/antigen-coupled APC on human T(h)1 cells appears to involve a reversible anergy mechanism leading to apoptosis, whereby the targeted T cells receive full or partial activation through the TCR, without coordinate co-stimulation. These data suggest dichotomous signaling requirements for inactivating cells of the T(h)1 and T(h)2 lineages that may have important implications for treatment of T(h)1-mediated autoimmune or inflammatory diseases.     

Decision-making styles of dietitians

Four decision-making styles (technician, planner, teacher, artist) were distinguished with Myers-Briggs Type Indicator (MBTI) results for 61 dietitians and 55 dietetic students. The "technician" style (impersonal, matter-of-fact analysis expressed in technical skills) was preferred to other styles by the greatest percentage of subjects studied. Subgroups of clinical dietitians, those 40 years old or older, and dietetic internship graduates preferred the "technical" style that is related to academic achievement in applied and physical sciences. Dietitians in administration, consulting, education, and public health indicated a preference for the "artistic" style (an insightful approach to possibilities expressed in an ability to communicate well with others). CUP graduates indicated the most diversity in style preferences. The "planner" style identified with researchers was preferred to the "artistic" style by students. Available data from groups of dietitians studied by other investigators supported these findings and indicated similarities among dietitians, school administrators, and medical technicians. Comparison between students in this and other samples indicated more differences than similarities, which may be due to differences in programs. Since all styles are useful within the profession, it is suggested that the identification and adaptation of style be included in education programs for dietetic students and practitioners.     

去甲硫氨酸全肠外营养对大鼠血清氨基酸谱的影响

目的观察去甲硫氨酸全肠外营养对大鼠血清氨基酸谱等的影响.方法 Wistar大鼠24只,随机分为含甲硫氨酸(+MetTPN,n=12)和去甲硫氨酸全肠外营养2组(-MetTPN,n=12),分别给予相应的TPN支持.治疗7d后,每组随机抽取6只大鼠处死,检测血清FAA(HPLC法)、肝肾功能和全血常规,同时作心、肺、肝、肾组织病理学检查.两组其余大鼠继续原TPN治疗,观察生存期.结果 -MetTPN组大鼠血清游离Met、Cys明显降低,Asp、Glu、Ser等显著增高;大鼠体重下降;血清总蛋白和白蛋白水平下降;血常规和肾功能未见明显异常;组织学检查见肝细胞轻度肿胀,细胞核仁增粗,心肺肾未见明显异常;平均生存18d.对照组上述检查未见异常,除一只大鼠因导管并发症于TPN第16d死亡,其余大鼠全部存活.结论 -MetTPN一周可致大鼠血清游离Met、Cys明显降低和Asp、Glu、Ser等显著增高,及轻度肝功能改变;随着-MetTPN时间延长,出现严重的代谢紊乱和器官功能障碍导致死亡.     

Rapid detection of convallatoxin using five digoxin immunoassays

Context. Cardiac glycosides of plant origin are implicated in toxic ingestions that may result in hospitalization and are potentially lethal. The utility of commonly available digoxin serum assays for detecting foxglove and oleander ingestion has been demonstrated, but no studies have evaluated the structurally similar convallatoxin found in Convallaria majalis (lily of the valley) for rapid laboratory screening, nor has digoxin immune Fab been tested as an antidote for this ingestion. Objective. We aimed to (1) evaluate multiple digoxin assays for cross-reactivity to convallatoxin, (2) identify whether convallatoxin could be detected in vivo at clinically significant doses, and (3) determine whether digoxin immune Fab could be an effective antidote to convallatoxin. Materials and methods. Cross-reactivities of purified convallatoxin and oleandrin with five common digoxin immunoassays were determined. Serum from mice challenged with convallatoxin was tested for apparent digoxin levels. Binding of convallatoxin to digoxin immune Fab was determined in vitro. Results. Both convallatoxin and oleandrin were detectable by a panel of commonly used digoxin immunoassays, but cross-reactivity was variable between individual assays. We observed measurable apparent digoxin levels in serum of convallatoxin intoxicated mice at sublethal doses. Convallatoxin demonstrated no binding by digoxin immune Fab. Conclusion. Multiple digoxin immunoassays detect botanical cardiac glycosides including convallatoxin and thus may be useful for rapid determination of severe exposures, but neutralization of convallatoxin by digoxin immune Fab is unlikely to provide therapeutic benefit.