Right frontal activation during the continuous performance test assessed with near-infrared spectroscopy in healthy subjects

Near-infrared spectroscopy (NIRS) is a non-invasive optical technique which has been successfully used to register substantial cerebral ischemia. There are indications that NIRS is sensible enough to detect also small metabolic changes during the performance of cognitive tasks. In the present study, two-channel NIRS of left and right anterior frontal brain areas was applied to investigate brain oxygenation of 10 healthy subjects carrying out the continuous performance test (CPT). Significant differences between the left and right hemisphere were found. These consisted of different changes in deoxyhaemoglobin (HHB), but not in oxyhaemoglobin (O₂HB) in right frontal brain areas compared to baseline during the test. Despite of some methodological restrictions, the findings suggest that the sensitivity of the NIRS-method is sufficient to detect brain oxygenation changes during cognitive activation. Furthermore, the results support the view that execution of the CPT is associated with prevalently right frontal activation.     

CSF cytology--the ongoing dilemma to distinguish neoplastic and inflammatory lymphocytes

To evaluate different morphological criteria for the distinction between inflammatory and neoplastic lymphocytes in the cerebrospinal fluid (CSF). Forty-two cytospin preparations of CSF from patients with confirmed CSF involvement by aggressive B-cell lymphoma or acute leukemia were compared with 26 samples of inflammatory diseases. CSF cytology was analyzed morphologically for preselected parameters of cell, cytoplasm and nucleic appearance, and the presence of mitoses or apoptoses. None of the evaluated parameters sharply discerns neoplastic and inflammatory changes. However, neoplastic cells were significantly larger. Moreover, irregular shape and pointed borders of the cytoplasm, and deep notches in the nucleus were significantly more frequent in neoplastic than in inflammatory lymphocytes. No single parameter is sufficient to detect neoplastic lymphocytes. Considering a combination of cell size and irregular shape of cell and nucleus, however, may improve the diagnostic accuracy of CSF dissemination by aggressive hematological malignancies.     

胶质瘤干细胞对替莫唑胺敏感性的研究

目的 探讨胶质瘤干细胞(GSC)对替莫唑胺(TMZ)的敏感性及耐药机制.方法 新鲜多形性胶质母细胞瘤(GBM)标本培养后获得GSC.免疫荧光技术榆测未分化GSC的CD133及分化生长GSC的GFAP的表达,MTS法检测对替莫唑胺的敏感性,流式细胞技术对CD133阳性细胞的比例进行定量,荧光标记的甲基化特异性PCR分析MGMT启动子区域的甲基化状态,Western blot检测抑癌基因PTEN的表达.结果 (1)5例GBM标本中成功获得GSC,符合肿瘤下细胞定义.(2)5个GSC细胞株多数对TMZ不敏感.其中,T509的半数抑制浓度(IC50)为22.3 μmol/L(敏感),T411的IC50为286.3 μmol/L(中度敏感),其余3个细胞株T402,T405及T509的IC50皆大于1000μmol/L(不敏感).(3)CD133阳性细胞比例大于10%的GSC细胞株对TMZ不敏感.(4)MGMT启动子区域呈去甲基化状态的GSC对TMZ不敏感或仅为中度敏感.(5)5个GSC细胞株中,PTEN表达水平差异大,与GSC对TMZ的敏感性无明显关联.结论 GSC对TMZ普遍耐药,与MGMT启动子区域甲基化状态及CD133阳性细胞有关,而与PTEN蛋白表达水平无明显关联.