均一吸收体中SPECT重建多解性的探讨

通过对重建图像噪声特性的分析，间接证明ＳＰＥＣＴ的解具有多样性。分别用ＴｒｅｔｉａｋＭｅｔｚ、Ｇｕｌｂｅｒｇ、富谷武浩等推导的３种等价重建方法和Ｂｅｌｉｎｉ等推导的重建方法，经计算机模拟重建衰减均匀分布的图像，先预置相同的重建图像的空间分辨率，再比较它们的噪声特性。两种方法重建图像的噪声分布：前者近图像边缘时增大，而后者减小，从而间接证明在假定均匀衰减条件下，ＳＰＥＣＴ的重建有多解性。     

吗啡受体显像剂7α-o-IA-DPN的合成

设计、合成了一种新的吗啡受体显像剂。选用吗啡拮抗剂特培洛啡（ｄｉｐｒｅｎｏｒｐｈｉｎｅ，ＤＰＮ），经乙酰化选择性保护苯环３位—ＯＨ，将乙烯锡烷作为弥补基引入ＤＰＮ分子７α支链淑醇基团位置，采用碘代锡烷标记法一步合成碘烷ＤＰＮ（７αｏｉｏｄｏａｌｙｌｄｉｐｒｅｎｏｒｐｈｉｎｅ，即７αｏＩＡＤＰＮ）。其标记率达９０％，比活度为８０ＴＢｑ／ｍｍｏｌ，放化纯度大于９５％。体外吗啡受体结合分析表明其具有很高的亲和力（Ｋｉ＝０．４ｎｍｏｌ／Ｌ）。结果表明：新合成的碘标记吗啡配体适合于ＳＰＥＣＴ活体吗啡受体显像研究。     

Natural history of atopic dermatitis and its relationship to serum total immunoglobulin E in a population-based birth cohort study

We investigated the natural history of atopic dermatitis (AD) in a population-based birth cohort and assessed whether children at risk of visible eczema at 5 years of age can be identified from total immunoglobulin E (IgE) levels measured at 8, 12 and 18 months. AD data collected included a whole body examination for visible eczema at 49 months (4 years) and 61 months (5 years) of age and parent completed questionnaire data throughout their early lives. Children were divided into four groups based on their natural history of early AD: persistent (AD at 1, 6, 18, 30 and 42 months, n  = 34), intermittent early onset (before 18  months of age, n  = 495), intermittent late onset (18–42 months of age, n  = 273) and unaffected ( n  = 429). Visible eczema at 5 years of age was present in 12.2% (117/957) (95% confidence interval [CI] 10.1–14.3%) of the children. Levels of total IgE at 8, 12 and 18 months of age were associated with early onset of AD, but not with AD of later onset. For all four natural history groups, the geometric mean total IgE at 12 months was higher in those who subsequently had visible eczema than those who did not. However, the degree of overlap was such that total IgE at 12 months of age was a poor predictor of eczema at age five. A cutoff point of 78 kU/l had the highest positive predictive value for visible eczema at 5 years of age of 28.6%, with a sensitivity of 12% and specificity of 95%.     

Avoidance of Nitrous Oxide for Patients Undergoing Major Surgery: A Randomized Controlled Trial

Background: Nitrous oxide is widely used in anesthesia, often administered at an inspired concentration around 70%. Although nitrous oxide interferes with vitamin B12, folate metabolism, and deoxyribonucleic acid synthesis and prevents the use of high inspired oxygen concentrations, the consequences of these effects are unclear.

Methods: Patients having major surgery expected to last at least 2 h were randomly assigned to nitrous oxide-free (80% oxygen, 20% nitrogen) or nitrous oxide-based (70% N2O, 30% oxygen) anesthesia. Patients and observers were blind to group identity. The primary endpoint was duration of hospital stay. Secondary endpoints included duration of intensive care stay and postoperative complications; the latter included severe nausea and vomiting, and the following major complications: pneumonia, pneumothorax, pulmonary embolism, wound infection, myocardial infarction, venous thromboembolism, stroke, awareness, and death within 30 days of surgery.

Results: Of 3,187 eligible patients, 2,050 consenting patients were recruited. Patients in the nitrous oxide-free group had significantly lower rates of major complications (odds ratio, 0.71; 95% confidence interval, 0.56-0.89; P = 0.003) and severe nausea and vomiting (odds ratio, 0.40; 95% confidence interval, 0.31-0.51; P < 0.001), but median duration of hospital stay did not differ substantially between groups (7.0 vs. 7.1 days; P = 0.06). Among patients admitted to the intensive care unit postoperatively, those in the nitrous oxide-free group were more likely to be discharged from the unit on any given day than those in the nitrous oxide group (hazard ratio, 1.35; 95% confidence interval, 1.05-1.73; P = 0.02).