体外诱导骨髓间充质干细胞向神经元样细胞分化的机制研究

目的体外诱导成人骨髓间充质干细胞(MSCs)向神经元样细胞分化,并探讨分化过程中多效蛋白(PTN)mRNA的表达,以了解MSCs向神经元样细胞分化的特性和机制。方法密度梯度离心加贴壁培养法分离成人MSCs,原代和传代培养。取第6代MSCs设对照和试验组进行诱导,诱导后30 min至3 d,观察细胞形态并计数。免疫细胞化学法和反转录-聚合酶链反应(RT-PCR)法测定分化后细胞神经细胞特异性表面标志神经元烯醇化酶(NSE)、微管相关蛋白(MAP)-2,胶原酸性蛋白(GFAP)和诱导前、诱导后12 h PTN mRNA的表达。结果接种24 h后MSCs开始贴壁,呈圆形或椭圆形。3 d后可见梭状细胞呈集落状生长,10～14 d融合。第5～6代时呈现较均一的成纤维细胞样形态。诱导后胞体向胞核收缩;出现双极及多极细胞。12 h变形细胞增多,细长突起相互连接。24 h后变形细胞增多不明显。诱导后12 h大部分细胞表达NSE(64.79±0.07)%、MAP-2(60.05±0.09)%,未检测到GFAP的表达,RT-PCR半定量检测有NSE mRNA的表达(0.66±0.15)。实验组诱导后12 h细胞有PTN mRNA的表达(0.689±0.017)。结论建立了稳定的成人MSCs培养增殖体系,MSCs可体外诱导分化为神经元样细胞,在分化过程中有外观形态变化和特异性标志物NSE和MAP-2的表达,同时有PTN mRNA的表达,提示PTN可能参与调控了MSCs向神经元样细胞的分化。     

Can Cerebrospinal Fluid Pressure Detect Catheter Complications in Patients Who Experience Loss of Effectiveness With Intrathecal Baclofen Therapy?

ObjectiveThe catheter status of patients who presented with loss of intrathecal baclofen (ITB) therapy effectiveness was investigated using measurements of cerebrospinal fluid (CSF) pressure transmitted through the catheter fluid path to the pump. The aim of the study was to estimate the appropriate threshold separating catheter complications from “normal” catheter function, and to compare catheter status based on CSF pressure with the clinical diagnosis.MethodsThis was a prospective, masked nonsignificant risk, research study. Patients (N = 47) received ITB for the treatment of severe spasticity and presented with symptoms of catheter malfunction. CSF pressure data were recorded using an external sensor connected to a needle inserted into the catheter access port. An algorithm calculated the energy of the variations in CSF pressure caused by respiration and heartbeat within the intrathecal space. These data were evaluated against a threshold that separated normal from abnormal catheter function. Catheter status based on the algorithm was compared with the clinical diagnosis.ResultsComplete data were available for 37 patients. Mean CSF pressure energy was significantly higher (p = 0.025; student t-test) for patients diagnosed with normal catheter function vs. catheters with complications. The CSF pressure algorithm matched the clinical diagnosis in 16 of 18 patients with catheter complications (sensitivity = 89%), and 13 of 19 patients with normal catheter function (specificity = 68%).ConclusionIn-clinic CSF pressure data acquisition is technically feasible. Overall, catheter status based on the algorithm demonstrated concordance with the clinical diagnosis in 29 of 37 patients (78.4%).     

Assessment of Patient Preference for Constant Voltage and Constant Current Spinal Cord Stimulation

Objectives: Spinal cord stimulation devices control energy by generating either constant voltage (CV) pulses or constant current (CC) pulses. This study aimed to investigate: 1) whether patients feel differences between CV and CC stimulation; 2) if patients prefer CV or CC stimulation. Methods: Fourteen patients blinded to the type of pulse generation received 20 randomized pairs of 15‐sec pulse trains (CC‐CV, CV‐CC, CV‐CV, or CC‐CC). Patients identified whether the pairs were the same or different, and if they preferred the first or second train. Results: There was no difference in charge‐per‐pulse input between CV and CC modes. Patients performed at chance level in identifying identical pairs (55.7 ± 24.1% correct, 10 trials), and slightly better in identifying different pairs (67.1 ± 25.2% correct, 10 trials). No patients correctly identified all pairs. Patients were categorized based on their performance in this task. Only three patients fell into a category where preference could be established with some confidence with respect to the group averages. Two of these patients preferred CV, while one patient preferred CC. Conclusion: The lack of patient ability to discriminate in this preliminary investigation suggests that patient preference for a stimulation type should not be the key determining factor in choosing a spinal cord stimulation system.     

Metal Carbonyls in the Petroleum Industry

Industrial conditions which utilize temperature, pressure, and carbon monoxide in the presence of metal catalysts are conducive to metal carbonyl formation. An evaluation of the thermodynamic equilibrium data associated with metal carbonyls shows a definite relationship between these parameters which allow us to construct nomographs concerning their equilibrium formation. Metal carbonyls represent a distinct medical hazard. Recommendations for safe exposure limits and safety devices for personnel protection are based on the toxicity associated with metal carbonyls. Analytical methods indicate that adequate monitoring of the carbonyls of nickel, cobalt, and iron can be obtained.     

Gout presenting as lobular panniculitis

A 37-year-old man presented with panniculitis of the legs that, on biopsy, showed aggregates of crystals whose appearance suggested sodium urate. Based on this finding, a uric acid level was obtained which proved to be markedly elevated. The patient subsequently developed gouty arthritis. Gout should be added to the differential diagnosis of causes of panniculitis, and biopsy specimens of panniculitis should be carefully examined for crystals.     

A comparative study of Spitz nevus and nodular malignant melanoma using image analysis cytometry

Image analysis cytometry can be used to estimate both nuclear DNA content and area in tissue sections. Since nodular malignant melanoma and Spitz nevus can show a remarkably similar light microscopic appearance, but may differ in behavior, we studied typical examples of these neoplasms to determine whether cytometric differences existed. Analysis of relative DNA content alone could not discriminate between these 2 entities in the 13 cases that we examined. However, Spitz nevi and nodular melanoma clearly differed in terms of maturation, which we defined as the difference between the mean nuclear size or mean nuclear DNA content of the uppermost and deepest melanocytes in each lesion. Maturation as defined by a decrease in mean nuclear DNA content proved highly significant (p less than 0.005). Only Spitz nevi showed a lesser DNA content in the deepest dermal cells as compared with upper dermal cells, suggesting that some Spitz nevi have an admixture of diploid and hyperdiploid cells in their upper portions, but mostly diploid cells in their deep portions. Only nodular melanoma showed higher mean DNA content in deep dermal cells as opposed to superficial dermal cells, suggesting that some nodular melanomas may either have clones of cells in their deep portions that have higher levels of ploidy, or more cells in the deep portion of melanomas may be in active phases of the cell cycle. Our study suggests that important cytometric differences exist between Spitz nevi and nodular melanoma, and that these could be exploited to develop cytometry into an adjunctive clinical technique.     

Cutaneous malignancy and human immunodeficiency virus disease

Certain skin cancers occur with increased frequency or altered course in patients infected with HIV. Malignant melanoma and squamous cell carcinoma are examples of cutaneous malignancies that have a more aggressive course in patients with HIV. Others, such as basal cell carcinoma, appear more frequently in this population but do not appear to be more aggressive. The incidence of HIV-associated Kapsosi's sarcoma has markedly decreased since the advent of HIV antiretroviral therapy. Our understanding of the pathogenesis of this malignancy and its unique management issues are fully reviewed. Cutaneous T-cell lymphoma (CTCL) is rare in this population. Other types of cutaneous lymphoma and HIV-associated pseudo-CTCL are discussed. This article addresses prevention, treatment, and follow-up strategies for this at-risk population. LEARNING OBJECTIVE: At the completion of this learning activity, participants should be familiar with the unique epidemiology, clinical course, and management of cutaneous malignancy in patients infected with HIV.