Uncertainty in Fitted Estimates of Apparent in Vivo Metabolic Constants for Chloroform

It has become common practice to rely on fitted estimates ofapparent in vivo metabolic constants (e.g., V_max and K_M) inparameterization of PBPK models. Yet, quantitative estimatesof precision in these fitted parameters are not routinely reported.Such information is needed to assess the reliability of modelpredictions. The purpose of this study was to assess the precisionin estimates of V_max and K_M for chloroform, accounting for boththe statistical uncertainties in parameter estimates from individualdata sets and any additional uncertainty due to differencesin the parameter estimates derived from various experiments.Joint confidence regions for V_max and K_M from each experiment,generated using maximum likelihood techniques, were used toevaluate these questions. Three previously published data setswere considered. Estimates of V_max and K_M obtained from thesedata sets differed more than could be explained as a consequenceof a limited number of observations, measurement error, or stochasticerror. Issues associated with the use of maximum likelihoodtechniques to estimate joint confidence regions, the estimationof metabolic constants from individual experiments within agas uptake study versus the full data set, the degree of overlapin the joint confidence regions for metabolic constants obtainedfrom separate data sets, and the implications for risk assessmentare discussed.     

猕猴桃汁抗环磷酰胺致突变作用的机理

目的用大鼠外周血双核淋巴细胞微核测试法（ＣＢＭＮＴ），在哺乳动物整体水平，研究猕猴桃汁抗环磷酰胺（ＣＰ）的致突变作用以及生物转化Ⅱ相酶的作用。方法测定大鼠外周血双核淋巴细胞微核细胞率及肝组织中总谷胱甘肽硫转移酶（ＧＳＴ）、尿苷二磷酸葡萄糖醛酸转移酶（ＵＤＰＧＴ）、谷氨酰胺转肽酶（γＧＴ）活性。结果猕猴桃汁对ＣＰ诱发的大鼠外周血双核淋巴细胞微核细胞率有显著抑制作用，能明显诱导大鼠肝脏总ＧＳＴ、ＵＤＧＴＰ活性，但对γＧＴ活性无显著影响。大鼠外周血双核淋巴细胞微核细胞率与总ＧＳＴ、ＵＤＧＴＰ活性呈明显负相关。结论猕猴桃汁抗ＣＰ致微核形成作用的机理可能是通过诱导机体外来化合物代谢解毒酶系，加速ＣＰ的代谢灭活     

Cytochrome P450 3A4 Activity in Premenopausal and Postmenopausal Women,Based on 6-β-Hydroxycortisol:Cortisol Ratios

Study Objective . To characterize cytochrome P450 (CYP) 3A4 activity in premenopausal and postmenopausal women by evaluating the urinary 6-β-hydroxycortisokcortisol ratio. Design . Prospective study. Subjects . Thirteen premenopausal and 13 postmenopausal women who were healthy and not receiving drugs known to affect CYP3A4 activity. Interventions . Beginning on day 2 of menses, premenopausal women collected first morning urine samples every other day for a complete menstrual cycle. Postmenopausal women collected first morning urine every other day for 28 days. Measurements and Main Results . Mean weekly 6-β-hydroxycortisol:cortisol ratios did not differ during the phase (week) of the menstrual cycle. Daily ratios did not differ in postmenopausal women. No difference between premenopausal and postmenopausal women was found on comparing overall median ratios. Conclusion . Cytochrome P450 3A4 activity as measured by 6-β-hydroxy cortisol:cortisol ratio did not differ by week of menstrual cycle, suggesting no menstrual cycle-related changes. Menopause does not appear to be associated with differences in CYP3A4 activity, compared with premenopause.     

Diagnosis of ligament rupture of the ankle joint: Physical examination, arthrography, stress radiography and sonography compared in 160 patients after inversion trauma

We prospectively enrolled 160 consecutive patients with inversion trauma of the ankle in a diagnostic protocol that included physical examination within 2 days and at 5 days after trauma, arthrography, stress radiography, and ultrasonography. 135 patients had pathological lateral ligament laxity on the later physical examination or lateral ligament rupture diagnosed on arthrography and they were operated on. 122 of these patients had ligament ruptures.

At clinical follow-up after a minimum of half a year, all of the patients who were not operated on had stable joints without signs of previous ligament ruptures.

Delayed physical examination at 5 days after the injury led to the highest overall sensitivity (96%) and specificity (84%) for the detection of a ligament rupture. Additional diagnostic procedures, at a considerable cost, yielded little additional information.     

化妆品皮肤损伤87例临床分析

为了了解常用化妆品对皮肤的损伤情况，作者研究了８７例化妆品皮肤损伤的临床特点，并对致病化妆品种类进行了分析。认为染发、洗发、祛斑霜类化妆品易引起急性损伤，但病程短，病因明确，易于诊断。而各种营养霜、护肤霜膏类化妆品多次涂搽后才缓慢致病，病程长，影响因素多，临床诊断需结合化妆品斑贴试验综合考虑     

Food choice in response to computer-generated nutrition information provided about meal selections in workplace restaurants

Aim : The study was designed to determine the effect of computerized nutrition information on consumer food choice in two workplace restaurants, one in which customers had to pay for their lunch and the other providing a free lunch. Methods : Customers entering the restaurants were asked to make selections from the menu on a computer screen. The energy, saturated fatty acids, non-milk extrinsic sugars and non-starch polysaccharide content of the meal selected was displayed graphically in proportion to the dietary reference values. They were given the opportunity to change their selected meal and the composition of all meals was recorded. Results : The nutritional composition of the first meal provoked 16% of customers to make a second selection. The proportion of energy in the first selection had been 31% higher for saturated fatty acids and 23% higher for non-milk extrinsic sugars than the first selection made by people who were satisfied with their first choice. In their second attempt they succeeded in reducing both nutrients to levels similar to those present in the meals selected by people who had been satisfied with their first selection. Customers>> selections for non-starch polysaccharide and energy did not differ between the groups. The main changes made by customers to achieve improved second choices were to omit dishes (44%), add dishes (19%), make changes within a menu category (46%), and make changes from one menu category to another (26%). Conclusion : It was concluded that provision of graphical nutrition information on a computer screen could be used by a subset of the users of both restaurants to enable them to improve their menu selections to a similar composition to that selected by the other people who used the computer system.