Simple and accurate quantification of dialysis in acute renal failure patients during either urea non-steady state or treatment with irregular or continuous schedules.

BACKGROUND: The quantification of dialysis in critically ill acute renal failure (ARF) patients requires a unifying expression that can establish kinetic equivalence amongst patients treated with irregular or frequent intermittent haemodialysis (IHD) schedules or with differing renal replacement therapies. EKRjc is a generalized form of the equivalent urea renal clearance (EKRc), and represents the equivalent continuous urea clearance that will result in the given time-averaged concentration of urea, for the given amount of urea removal. The suitability of EKRjc for the measurement of dialysis dose in this setting is examined. SUBJECTS AND METHODS: 420 weeks of renal replacement therapy (IHD and continuous renal replacement therapy) were simulated in 15 virtual 'patients' using a variable volume double pool urea kinetic model. Additional data from eight ARF patients were used to exemplify calculations. 1260 EKRjc values were calculated using both formal urea kinetic modelling, as well as a simplified method that requires input of changes in patient fluid state and blood urea nitrogen concentrations over a period of observation, in addition to an initial estimate of patient post-dialysis urea distribution volume (V(T)). RESULTS: EKRjc is shown to provide a unifying expression of dialysis dose irrespective of IHD schedule or renal replacement therapy. EKRjc is shown to be independent from the assumption of the urea steady state, and intrinsically normalized to patient urea distribution volume to allow dose comparisons between patients of different size. Residual renal urea clearance is easily incorporated where present. EKRjc is easily calculated using the simplified method without the need for iterative urea kinetic modelling. The accuracy of this simplified method is maintained when the initial estimation of V(T) is both 25% greater or smaller than the true value. Calculation of EKRjc is exemplified using the clinical data. CONCLUSIONS: EKRjc is the most suitable urea kinetic expression for the quantification of dialysis in critically ill ARF patients.     

Skin repair by transplantation of cultured keratinocytes

Improvement of methods for culturing skin cells stimulates their wide application in the treatment of a variety of skin injuries. A method for restoration of the skin with cultured epithelium and cultured epithelium in combination with a derma analog (collagen gel with fibroblasts) was developed. Possible mechanisms for skin repair after transplantation of cultured allogenic skin transplants were analyzed.     

工业企业噪声危害的综合评价方法

目的 研究工业企业生产性噪声危害的综合评价方法。方法 选择某市7个工业行业的22个工业企业方研究对象,测定生产性噪声强度和噪声作业人员的听力,按照平均声压级的计算方法求得平均等效声级,并与噪声作业人员的听力损失检出率进行方差分析、相关分析和曲线拟合。结果 听损检出率随平均等效声级的增加而呈明显的增加趋势,平均等效声级与噪声作业人员的听损检出率呈密切的指数正相关关系（相关关系r为0．81245）。结论 平均等效声级可以作为评价和比较工业企业的噪声危害程度的综合指标。     

Comparative analysis of different collagen-based biomaterials as scaffolds for long-term culture of human fibroblasts

Biodegradable scaffolds, along with cells, are important components of most tissue-engineered consructs. In the study, there is a comparison of the behaviour of human fibroblasts cultured for up to six weeks in four diffeeent collagen-based three-dimensional matrices, in the form of sponges composed of pure native type I collagen (control), of collagen-GAG-chitosan (CGC) and of collagen cross-linked by two concentrations of diphenylphosphorylazide (DPPA-2 and DPPA-3). Variations in size and weight of the sponges, as well as fibroblast growth and migration, and total protein and collagen synthesis, are determined with time in culture. Owing to their low thermal stability, the partial denaturation and dissolution of the control sponges after incubation at 37°C lead to considerable contraction and low cell proliferation. CGC sponges, stabilised by ionic interactions between the different components, show, after six weeks, limited contraction (20%) and weight increase (10% when seeded) and high growth (threefold increase). Similar results are obtained with weakly, cross-linked (DPPA-2) collagen sponges. Highly crosslinked (DPPA-3) sponges do not contract, whereas weight gain and cell proliferation are no different from those found with CGC and DPPA-2 sponges. Similar levels of total protein and collagen synthesis shown for fibroblasts seeded in different matrices, with a slight general decrease (twofold) after three weeks, a much lower value than that observed with fibroblasts in culture within a contracted collagen gel (sixfold). Furthermore, the fraction of neo-synthesised collagen deposited in the sponges after six weeks represents more than 60% of the total, compared with only 10% obtained with fibroblasts in monolayer culture or 30% within a collagen gel. These results indicate that the matrices, particularly the CGC and DPPA-2 sponges, provide excellent supports for fibroblast growth and the formation of dermal and skin equivalents.     

吴茱萸配方颗粒等效性研究

目的：以吴茱萸为示范性研究对象,探索建立评价配方颗粒和临床煎剂间的等效比例关系。方法：以吴茱萸胺、吴茱萸次碱、吴茱萸内酯、吴茱萸总生物碱、出膏率为评价指标,以临床煎剂的煎煮方法制备的10批对照汤剂的平均值为临床煎剂的评价标准,以多个临床常用的炮制品为研究对象,比较配方颗粒和临床煎剂间的等效比例关系,并以药效指标进一步验证等效比的正确性。结果：通过系统的比较,配方颗粒和临床煎剂间的比例关系在吴茱萸各饮片间约为2,药效学比较证实该比例下的配方颗粒与相应饮片间的药效强度无显著差异。结论：该等效比计算模型可做为配方颗粒生产企业在换算等效关系时参考；但值得注意的是：药物不同,其等效比可能不同,应根据生产工艺、生产条件等进行深入研究,进而得到各药物的等效比,最终的等效比关系仍需临床验证的进一步肯定。     

Applicability of the single equivalent point dipole model to represent a spatially distributed bio-electrical source

Although the single equivalent point dipole model has been used to represent well-localised bio-electrical sources, in realistic situations the source is distributed. Consequently, position estimates of point dipoles determined by inverse algorithms suffer from systematic error due to the non-exact applicability of the inverse model. In realistic situations, this systematic error cannot be avoided, a limitation that is independent of the complexity of the torso model used. This study quantitatively investigates the intrinsic limitations in the assignment of a location to the equivalent dipole due to distributed electrical source. To simulate arrhythmic activity in the heart, a model of a wave of depolarisation spreading from a focal source over the surface of a spherical shell is used. The activity is represented by a sequence of concentric belt sources (obtained by slicing the shell with a sequence of parallel plane pairs), with constant dipole moment per unit length (circumferentially) directed parallel to the propagation direction. The distributed source is represented by N dipoles at equal arc lengths along the belt. The sum of the dipole potentials is calculated at predefined electrode locations. The inverse problem involves finding a single equivalent point dipole that best reproduces the electrode potentials due to the distributed source. The inverse problem is implemented by minimising the χ² per degree of freedom. It is found that the trajectory traced by the equivalent dipole is sensitive to the location of the spherical shell relative to the fixed electrodes. It is shown that this trajectory does not coincide with the sequence of geometrical centres of the consecutive belt sources. For distributed sources within a bounded spherical medium, displaced from the sphere's centre by 40% of the sphere's radius, it is found that the error in the equivalent dipole location varies from 3 to 20% for sources with size between 5 and 50% of the sphere's radius. Finally, a method is devised to obtain the size of the distributed source during the cardiac cycle.     

Guidelines for Patient-Centered Opioid Prescribing and Optimal FDA-Compliant Disposal of Excess Pills after Inpatient Operation: Prospective Clinical Trial

1. Download : Download high-res image (262KB)
2. Download : Download full-size image

     

职业健康检查中摄胸片取代胸透的探讨

目的探讨基层疾病预防控制中心在职业健康检查中用摄胸片取代胸部透视的利弊。方法分别从辐射危害、阳性检出率和各自优缺点3个角度进行分析比较。结果在职业健康检查中摄胸片机体所受的X射线有效剂量当量比胸部透视小11.92倍,阳性检出率是胸部透视的5倍,二者阳性检出率比较,差异有统计学意义(χ2=41.77,P0.01)。且胸片显影清晰,对比度高,能发现早期肺微小病变和客观记录图像等优点,比胸部透视更适合在职业健康检查中应用。结论为了保障劳动者合法健康权益,减少有害X射线辐射,提高职业病(尘肺病)的检出率,提倡在基层疾病预防控制中心的职业健康检查中用X射线胸部摄片取代常规胸部透视的做法。