A New Meal Absorption Model for Artificial Pancreas Systems

Background:Artificial pancreas (AP) systems reduce the treatment burden of Type 1 Diabetes by automatically regulating blood glucose (BG) levels. While many disturbances stand in the way of fully closed-loop (automated) control, unannounced meals remain the greatest challenge. Furthermore, different types of meals can have significantly different glucose responses, further increasing the uncertainty surrounding the meal.Methods:Effective attenuation of a meal requires quick and accurate insulin delivery because of slow insulin action relative to meal effects on BG. The proposed Variable Hump (VH) model adapts to meals of varying compositions by inferring both meal size and shape. To appropriately address the uncertainty of meal size, the model divides meal absorption into two disjoint regions: a region with coarse meal size predictions followed by a fine-grain region where predictions are fine-tuned by adapting to the meal shape.Results:Using gold-standard triple tracer meal data, the proposed VH model is compared to three simpler second-order response models. The proposed VH model increased model fit capacity by 22% and prediction accuracy by 12% relative to the next best models. A 47% increase in the accuracy of uncertainty predictions was also found. In a simple control scenario, the controller governed by the proposed VH model provided insulin just as fast or faster than the controller governed by the other models in four out of the six meals. While the controllers governed by the other models all delivered at least a 25% excess of insulin at their worst, the VH model controller only delivered 9% excess at its worst.Conclusions:The VH Model performed best in accuracy metrics and succeeded over the other models in providing insulin quickly and accurately in a simple implementation. Use in an AP system may improve prediction accuracy and lead to better control around mealtimes.     

A prospective randomized trial to compare triple dose mezlocillin with triple dose cefuroxime plus metronidazole as prophylaxis in colorectal surgery

The results of a prospective randomized clinical trial to compare three dose regimens of mezlocillin with cefuroxime plus metronidazole for prophylaxis in emergency and elective colorectal surgery are reported. Severe wound infection occurred in five patients (10%) receiving mezlocillin and in four patients (7%) receiving cefuroxime and metronidazole. There were two episodes of septicaemia, each in the mezlocillin group. The total number of surgically related infections was less with cefuroxime plus metronidazole (n = 10) compared with mezlocillin (n = 17), but this was not statistically significant (P greater than 0.1).     

The structure of radiation oncology practices in the continental United States

The American College of Radiology periodically collects data on radiation oncology facilities with megavoltage equipment. The results of the 1986 survey are summarized, with specific reference to the substantial growth in free-standing facilities.     

肝脏可溶性复合物不同剂量、不同途径移植对肿瘤细胞增殖抑制的体内外实验

目的:肝脏可溶性复合物具有保护肝脏、刺激肝组织再生等生物学活性,观察天然物质肝脏可溶性复合物对肿瘤细胞生长增殖的抑制作用.方法:实验于2006-05/2007-02在四川大学华西医院生物治疗国家重点实验室实验肿瘤研究室完成.①分离人胚胎、成年及新生小鼠肝脏组织,生理盐水清洗、剪碎、筛网过滤,用生理盐水制备混悬液,3 000 r/min离心,收集上清,制备肝脏可溶性复合物.②体外实验:用上述不同来源的肝脏可溶性复合物体外处理肿瘤细胞,四甲基偶氮唑盐比色法测定其对乳腺癌细胞EMT6增殖的影响.③体内实验:观察成年鼠肝脏可溶物质对乳腺癌细胞EMT6体内生长的抑制作用及其对荷瘤鼠生存状况的影响,包括不同给药剂量及不同给药途径两个实验,给药途径包括在接种肿瘤细胞部位的对侧腋下、同侧腋下、腹腔注射及灌胃等.结果:①体外实验显示不同来源的肝脏可溶性复合物能明显抑制肿瘤细胞EMT6增殖率,肿瘤增殖抑制率均显著高于血清白蛋白处理组(P＜0.05),并呈剂量依赖性.②成年鼠肝脏可溶物质8mg/L组抑瘤率高于2,4 mg/L组(P＜0.05),未观察到明显毒副效应.③比较不同给药途径,成年鼠肝脏可溶物质同侧注射组的抑瘤率较其他3组的抑瘤率高(P＜0.05),各成年鼠肝脏可溶物质给予组的体质量增长率比相应生理盐水对照组高(P＜0.05).④与相应生理盐水对照组比较,在同侧腋下注射成年鼠肝脏可溶物质的小鼠生存期明显延长(P＜0.05).结论:肝脏可溶性复合物具有抑制肿瘤细胞生长的作用,并且呈一定的剂量依赖性.不同的给药途径中,在接种肿瘤细胞部位的同侧腋下给药抑瘤效果最好.     

山东泰安地区两个自然村人群血脂状况调查

目的:调查了解山东泰安地区农村人群的血脂水平,为该地区农民心脑血管疾病的预防提供基础数据。方法:实验于2006-06随机选取泰安市两个自然村650人进行健康检查,男270人,女380人,年龄2～88岁。①650人均于早晨空腹采集静脉血3mL,静置凝固后,2h内分离血清,采用全自动生化分析仪常规测定患者血脂指标总胆固醇、三酰甘油水平。②总胆固醇>5.2mmol/L判定为高胆固醇血症,三酰甘油>1.7mmol/L判定为高三酰甘油血症。结果:650人全部完成血样采集与血脂指标检测。①不同性别血脂水平比较:被检人群男性三酰甘油水平显著高于女性[(1.16±1.47),(0.95±0.84)mmol/L,P<0.05];男女总胆固醇水平基本相似(P>0.05)。②不同年龄段血脂水平比较:8人因具体年龄段不祥被排除,剩余642人分为3个年龄段:2～30岁、31～50岁、51～88岁。结果31～50岁人群三酰甘油水平显著高于2～30岁人群[(1.14±1.47),(0.88±0.70)mmol/L,P<0.05],略高于51～88岁人群(P>0.05);51～88岁人群总胆固醇水平>31～50岁人群>2～30岁人群,相邻年龄段间比较差异均有显著性意义(P<0.001)。③各年龄段男女间血脂水平比较:2～30岁人群和51～88岁人群三酰甘油水平性别间差异均无显著性意义(P>0.05),但总胆固醇水平女性均显著高于男性[(2.38±1.47),(1.85±1.26)mmol/L,P<0.05;(4.48±0.92),(4.18±0.76)mmol/L,P0.01]。31～50岁人群男性三酰甘油水平显著高于女性[(1.51±2.06),(0.90±0.80)mmol/L,P<0.01],总胆固醇水平基本相似(P>0.05)。④各年龄段男女高血脂症构成比:31～50岁人群高三酰甘油血症构成比显著高于2～30岁、51～88岁人群(23.1%,5.5%,9.3%,P<0.01);随着年龄增高,各年龄段高胆固醇血症构成比逐渐升高,相邻年龄段间差异均有显著性意义(2.7%,8.6%,15.6%,P<0.01)。31～50岁人群男性高三酰甘油血症、高胆固醇血症的构成比显著高于女性(P<0.01);2～30岁、51～88岁人群男女间高血脂症的构成比基本相似(P>0.05)。结论:①山东泰安地区农村人群高三酰甘油血症,31～50岁年龄段患病率最高;高胆固醇血症患病率随年龄增长逐步上升,提示中年人健康体检尤为重要。②高脂血症应从青少年开始加大预防和保健力度,进行广泛和反复的健康教育,倡导健康的生活方式和生活行为。