A New Method for Estimating Dermal Absorption from Chemical Exposure. 3. Compared with Steady-State Methods for Prediction and Data Analysis

Purpose. This paper compares unsteady-state and steady-state methods for estimating dermal absorption or analyzing dermal absorption data. The unsteady-state method accounts for the larger absorption rates during short exposure times as well as the hydrophilic barrier which the viable epidermis presents to lipophilic chemicals. Methods. Example calculations for dermal absorption from aqueous solutions are presented for five environmentally relevant chemicals with molecular weights between 50 and 410 and log₁₀K_ow between 0.91 and 6.8: chloromethane, chloroform, chlordane, 2,3,7,8-TCDD, and dibenz(a,h)anthracene. Also, the new method is used to evaluate experimental procedures and data analyses of in vivo and in vitro permeation measurements. Results. In the five example cases, we show that the steady-state approach significantly underestimated the dermal absorption. Also, calculating permeability values from cumulative absorption data measured for exposure periods less than 18 times the stratum corneum lag time will overestimate the actual permeability. Conclusions. In general, steady-state predictions of dermal absorption will underestimate dermal absorption predictions which consider unsteady-state conditions. Permeability values calculated from data sets which include unsteady-state data will be incorrect. Strategies for analyzing in vitro diffusion cell experiments and confirming steady state are described.     

介入神经放射治疗43例

１９８５～１９９３年对４３例脑血管病及脑肿瘤患者应用介入神经放射治疗方法进行了５１次治疗，包括外伤性颈内动脉海绵窦瘘的球囊栓塞治疗８例；脑、脊髓血管畸形的栓塞治疗１７例；各种脑肿瘤术前栓塞７例；经皮穿刺血管内成型治疗脑供血动脉狭窄３例和脑胶质瘤超选择化疗８例，效果良好，介入神经放射治疗已成为重要的临床治疗手段，是某些脑血管疾病的首选治疗方法。     

PERCUTANEOUS LAPAROSCOPIC CHOLECYSTECTOMY: INDICATIONS,CONTRAINDICATIONS AND COMPLICATIONS

The indications, contraindications and complications of percutaneous laparoscopic cholecystectomy (PLC) were established from a group of 308 patients referred for cholecystectomy. Of the 308 patients 86% underwent PLC, 5% were commenced laparoscopically, but converted to open cholecystectomy and 9% were performed as open cholecystectomy from the outset. Complications included two bile leaks from the gall-bladder bed, one cystic duct stump leak and three retained stones. Pre-operative rather than intra-operative duct imaging was used so that common duct stones could be removed before operation. PLC is a safe procedure that has now become the standard technique for cholecystectomy.     

应用国产球囊导管经皮球囊二尖瓣成形术12例报告

本文报告经皮球囊二尖瓣成形术治疗二尖瓣狭窄12例。10例术前平均左房压为18mmHg～40mmHg(26.7±7.15mmHg),术后即刻为4mmHg～18mmHg(10.6±3.86mmHg)P<0.01。跨瓣压差术前10mmHg～40mmHg(19.6±9.05mmHg),术后为0～5mmHg(2.65±2.21mmHg)P<0.01。1例失败,1例术后发生二尖瓣关闭不全急性左心衰竭死亡。     

Membrane-coated fiber array approach for predicting skin permeability of chemical mixtures from different vehicles.

A membrane-coated fiber (MCF) array approach was developed for quantitative assessment of skin absorption from chemical mixtures, which was based on the similarity in the absorption mechanisms of the MCF membrane and the stratum corneum of the skin. A set of probe compounds were used to detect the relative molecular interaction strengths of chemicals with the vehicle and the membranes, which provided a linkage between the skin permeability (log k) and MCF partition coefficients (log KF). A predictive model was established via multiple linear regression analysis of the data matrix of experimentally measured log k value and log KFm values; log k=a0+a1 log KF1+a2 log KF2+...+an log KFm, where m is the number of diverse MCFs. Twenty-five probe compounds and three MCFs (polydimethylsiloxane for lipophilic, polyacrylate for polarizable, and CarboWax for polar interactions) were used to demonstrate the model development processes in the MCF array approach. The skin permeability of the probe compounds was measured with conventional diffusion cell experiments using dermatomed porcine skin. Three predictive models were established for skin permeability prediction from chemical mixtures in water, 50% ethanol, and 1% sodium lauryl sulfate (SLS) with R2 values of 93, 91, and 83, respectively. The log k and log KF values were considerably altered by the addition of ethanol or SLS into the dose vehicle; however, their correlations to skin permeability remained strong under various conditions. These results suggested that the experimentally based MCF array approach can be used to predict skin absorption from chemical mixtures in different vehicles or formulations.     

Subhepatic collections complicating laparoscopic cholecystectomy: Percutaneous management

Ten patients with subhepatic fluid collections complicating laparoscopic Cholecystectomy were successfully treated by interventional radiological procedures. The series included five abscesses, three hematomas, one biloma, and one serous collection. Abdominal pain or fever developed from 3 to 21 days after the laparoscopic intervention. All patients were asymptomatic 72 h after percutaneous drainage and there were no complications related to the procedure. Subhepatic fluid accumulations are common findings after laparoscopic cholecystectomies and have been considered an unreliable indicator of infection or other postoperative complications. However, the significance of these collections should not be underestimated in symptomatic patients. In such cases we propose diagnostic aspiration and drainage, when necessary, to safely and promptly establish the precise diagnosis and treatment. More serious complications can be avoided by early percutaneous intervention.     

经皮顺行交锁钉治疗股骨干骨折

目的:评价经皮顺行交锁钉治疗股骨干骨折的临床疗效.方法:对79例82处股骨干骨折采用髋部小切口经皮顺行交锁钉治疗,观察疗效.结果:75例(92%)获得了良好的解剖对位并达到一期愈合,6例(8%)迟缓愈合.另外,由于再次手术1例(1%)发生了深部感染.失血量较少(平均小于100 mL),切口平均长25 mm.1年后随访只有10%髋部疼痛.结论:与传统手术方式相比,经皮技术术中出血少、对周围组织创伤少,是一个安全又有效的方法.     

A "grapple hook" technique using a deflectable tip catheter to facilitate complex proximal circumflex interventions.

We present two patients with angulated, proximal left circumflex lesions, one a chronic total occlusion and one an acute subtotal occlusion. In both cases, use of the deflectable tip Venture Catheter (Velocimed, Minneapolis, MN) facilitated guide wire passage and successful percutaneous coronary intervention (PCI) after prior attempts at guide wire passage with standard wires were unsuccessful.     

New approach to management of intraaortic balloon pumps in patients with peripheral vascular disease: Case reports of four patients requiring urgent IABP insertion

Four selected cases of emergent IABP insertion in PV patients are presented. After angiographic documentation of critical iliac stenosis, conservative peripheral angioplasty was performed prior to IABP insertion. No patient experienced a peripheral ischemic event associated with IABP use. © 1992 Wiley-Liss, Inc.