T2 estimates in healthy and diseased brain tissue: a comparison using various MR pulse sequences

Fourteen patients and five healthy individuals underwent magnetic resonance (MR) imaging to determine an effective multiple spin echo pulse sequence for estimating T2. Lesions examined included infarction, glioma, multiple sclerosis, and acute hematoma. A pulse repetition time (TR) of 1,500 msec and echo delays (TEs) of 25, 50, 75, and 100 msec were used. Computed T2 images were derived from all four echoes, the first two echoes, and the first and fourth echoes. T2 values were obtained from specific brain locales using region-of-interest analysis. Use of either the first two echoes or the first and fourth in the T2 fit provided T2 estimates which closely correlated with that of the four-echo analysis. The noise level in T2 maps constructed from the 25- and 100-msec echoes was modestly (typically 10%) higher than that from four echoes; noise level from the 25- and 50-msec echoes was markedly higher, typically 60%. This behavior is remarkably consistent with that predicted from theory. All 19 subjects displayed consistent relative T2 values for specific brain structures; in 13, the absolute T2 values fell within a limited range. Despite the high sensitivity of T2 images, their specificity in the detection of most brain disease appears limited except in acute intracerebral hematoma, which exhibited a decreased T2 relaxation time using high-field-strength MR imaging.     

正交试验法优选冬凌草的提取工艺

目的：研究冷浸提取法中冬凌草的最佳提取条件。方法：采用正交试验法，以溶剂用量，提取时间和提取次数３个因素，每个因素选取３个水平进行实验。结果：因素Ａ和因素Ｂ对冬凌草甲素的含量均有显著的影响，因素Ｃ则有一定的影响。结论：最佳工艺Ａ３Ｂ３Ｃ２，即倍量９５％，ＥｔＯＨ提取２次，每次６ｄ。     

Going Dutch in nocturnal enuresis

Based on several intervention programmes, a strategy for the treatment of nocturnal enuresis has recently been developed by an expert committee in the Netherlands. It consists of three parts. First, two structured interviews are given: one to differentiate between enuresis and incontinence and one to detect associated problems such as diurnal enuresis, constipation or behavioural problems. Secondly, a medical examination is made, confined to the inspection of the external genitalia and lower back, palpation of the abdomen and urine examination. Thirdly, the following guidelines for treatment at different age levels are applied: up to the age of 6 years no intervention is needed; between the ages of 6 and 8 years, lifting out of bed and/or the calendar method; between the ages of 8 and 12 years, enuresis alarm (if not successful, medication with desmopressin is prescribed for a restricted period of time), and ambulatory dry-bed training in a group setting may follow; over 13 years of age, clinical dry-bed training according to the Messer/Azrin method is advised. According to the expert committee, these guidelines offer sufficient possibilities to deal with the problem of nocturnal enuresis.     

Evaluation of four methods for platelet compatibility testing

Four platelet compatibility assays were performed on serum and platelet or lymphocyte samples from 38 closely HLA-matched donor/recipient pairs involved in 55 single-donor platelet transfusions. The 22 patients studied were refractory to transfusions of pooled random-donor platelets. Of the four assays (platelet suspension immunofluorescence, PSIFT; 51Cr release; microlymphocytotoxicity; and a monoclonal anti-IgG assay, MAIA), the MAIA was most predictive of platelet transfusion outcome (predictability, 74% for one-hour posttransfusion platelet recovery and 76% for 24-hour recovery). The only other assay to reach statistical significance was the PSIFT (63% predictability for one-hour posttransfusion recovery). The degree of HLA compatibility between donor and recipient (exact matches v those utilizing cross-reactive associations) was unrelated to the ability of the MAIA to predict transfusion results. The MAIA may be capable of differentiating HLA antibodies, ABO antibodies, and platelet-specific antibodies responsible for failure of HLA-matched and selectively mismatched single-donor platelet transfusions.     

Rheumatoid arthritis: explanatory power of specific radiographic findings for patient clinical status

Radiographs of the hands and wrists of 201 patients with rheumatoid arthritis (RA) were scored for erosion, joint space narrowing, and malalignment. The explanatory power of these findings for measures of clinical status was studied with stepwise multiple linear regression analyses. Radiographic scores explained 59.2% of variation in physical joint count deformity scores, 58.5% of variation in limited motion scores, 22.5% of variation in grip strength scores, 20.5% of variation in button test scores, and 13.5% of variation for the American Rheumatism Association (ARA) Functional Class. Malalignment scores best explained variation in physical deformity, limited motion, and button test scores; joint-space-narrowing scores best explained variation in grip strength; erosion scores best explained variation in ARA Functional Class. When age, duration of disease, erythrocyte sedimentation rate, and rheumatoid factor titer were included in the regression analyses, results were similar to those without these variables. Therefore quantitative scores of specific radiographic findings are in themselves explanatory for measures of clinical status.     

VitC/Fe2+对细胞生长状态的影响

0 引言 正常生物体内的自由基产生和清除是处在平衡状态的,外界环境中的自由基易与体内多种物质发生化学反应,并与内源性自由基一起影响着细胞的生长、分化及死亡过程[1～4],但不同实验的结果存在一些差别,甚至矛盾的现象,如过氧化氢可刺激细胞生长或引起细胞凋亡,这提示我们对自由基作用于细胞的剂量-反应关系进行研究.     

Atypical distribution of Pneumocystis carinii infiltrates during radiation therapy

Bilateral peripheral pulmonary infiltrates caused by Pneumocystis carinii developed in a patient undergoing mediastinal irradiation after chemotherapy for Hodgkin disease. The paramediastinal part of the lung included within the treatment port remained clear during the 2 1/2 weeks of radiation therapy. The distribution of the pneumocystis infiltrates was altered by the radiation, producing a pattern that is the "radiographic negative" of typical post-radiation therapy paramediastinal fibrosis.