Maintenance of growth in cystic fibrosis despite reduction in pancreatic enzyme supplementation

Twenty one children with cystic fibrosis were advised to decrease their pancreatic enzyme supplement (PES) dose to less than 10,000 units lipase/kg/day. Mean PES dosage was significantly decreased in 15 patients from 18,380 to 8647 units lipase/kg/day. There were no significant changes in energy or fat intake, but there were significant increases in weight SD score, height SD score, and weight/height ratio.     

Close mapping of the focal non-epidermolytic palmoplantar keratoderma (PPK) locus associated with oesophageal cancer (TOC)

Focal non-epidermolytic palmoplantar keratoderma (PPK or palmoplantar ectodermal dysplasia type III) is associated with oesophageal cancer in three families: two large pedigrees located in Liverpool, UK and in the midwestern American states and one smaller family from Germany. In these families, the PPK is inherited as autosomal dominant and has a late onset, usually manifesting between 7 and 8 years of age. The disease is characterised by thickening of the pressure areas of the soles, but is not restricted to the feet and also presents with oral leukokeratosis and follicular hyperkeratosis. The disease locus [previously termed the "tylosis oesophageal cancer gene' (TOC) locus] has been mapped to 17q23-qter by linkage analysis. This region is located telomeric to the keratin 16 gene, in which mutations have been identified in focal PPK families who show no increased cancer risk. We describe the close mapping of this locus to the interval between AFMb054zf9 and D17S1603 using haplotype analysis of additional Genethon markers in the region and show that although the American family is unlikely to be related to either of the other two, the UK and German pedigrees may share a common descent. This work provides a basis for positional cloning and candidate gene analysis in order to identify a gene that may be involved in familial oesophageal cancer.      

Students and tutors' social representations of assessment in problem-based learning tutorials supporting change

Background  

Medical programmes that implement problem-based learning (PBL) face several challenges when introducing this innovative learning method. PBL relies on small group as the foundation of study, and tutors facilitate learning by guiding the process rather than teaching the group. One of the major challenges is the use of strategies to assess students working in small groups. Self-, peer- and tutor-assessment are integral part of PBL tutorials and they're not easy to perform, especially for non experienced students and tutors. The undergraduate PBL medical programme was introduced in 2003, and after two years the curriculum committee decided to evaluate the tutorial assessment in the new program.     

Digital processing of radiographic images from PACS to publishing

Several studies have addressed the implications of filmless radiologic imaging on telemedicine, diagnostic ability, and electronic teaching files. However, many publishers still require authors to submit hard-copy images for publication of articles and textbooks. This study compares the quality digital images directly exported from picture archive and communications systems (PACS) to images digitized from radiographic film. The authors evaluated the quality of publication-grade glossy photographs produced from digital radiographic images using 3 different methods: (1) film images digitized using a desktop scanner and then printed, (2) digital images obtained directly from PACS then printed, and (3) digital images obtained from PACS and processed to improve sharpness prior to printing. Twenty images were printed using each of the 3 different methods and rated for quality by 7 radiologists. The results were analyzed for statistically significant differences among the image sets. Subjective evaluations of the filmless images found them to be of equal or better quality than the digitized images. Direct electronic transfer of PACS images reduces the number of steps involved in creating publication-quality images as well as providing the means to produce high-quality radiographic images in a digital environment.     

Comparison of radiographic image quality from four digitization devices as viewed on computer monitors

The objective of this study was to compare the quality of radiographic images digitized from commercial-grade and consumer-grade digital cameras and scanners as viewed on computer monitor. Radiographic images were digitized from hardcopy film using a commercial-grade laser scanner, a consumer-grade desktop flatbed scanner, a commercial-grade digital camera, and a consumer-grade digital camera. The quality of images without and with grayscale histogram adjustment was evaluated subjectively by 10 board-certified radiologists. Optical density response was evaluated objectively using a grayscale test pattern. There was no significant difference in subjective quality among images digitized with the commercial scanner, consumer scanner, and commercial camera. The quality of images digitized with the consumer camera was lower than the other 3. Objective tests showed the commercial scanner to have the most linear optical density response. For the purpose of viewing images on a computer monitor, a consumer-grade desktop scanner can produce images of similar quality to those produced by more expensive laser commercial-grade scanners and digital cameras and provides cost-efficient means to digitize radiographic plain films. A consumer-grade camera may not be optimal for use in this setting.     

1,1-二烷基-4-(3-溴丙酰基)-哌嗪溴化物的合成及生物活性研究

设计合成了七种新的1,1-二烷基-4-(3-溴丙酰基)哌嗪季铵盐溴化物,通过IR,¹HNMR和元素分析证实其结构。初步生物活性试验结果表明,Ⅵa,Ⅵc和Ⅵe～g有明显的镇痛活性,Ⅵe～g还有较好的抗氧化SOD活性,但未发现有抗肿瘤作用。     

醋氨酚缓释包衣颗粒研究

包衣颗粒体外溶出试验证明在释放量达66%以前为零级恒速释放,此后释放速率降低为非零级释放。颗粒在室温下密闭贮存21个月后,释放速率增快,但仍为零级释放,也是在释放量达66%以后转变为非零级释放。用尿药排泄速率法研究了包衣颗粒的体内动力学并与常规片剂作比较,并测出两者的消除速率常数。常规片剂所得药物t 1/2=3.21h,而包衣颗粒剂所得半衰期约延长2.5倍。通过吸收百分率与体外溶出百分率在不同时间下数值的比较得到线性关系,相关系数r=0.9886。说明体外溶出数据可以作为控制吸收率的依据。按一级吸收一室模型公式计算了一定剂量下的血药浓度,在13h以内血药浓度都在治疗浓度范围(5～20μg/ml)以内。最高浓度为10.5μg/ml,达峰时间为3.27h。本品一次服1.1g可延效12h。     

Metabolic activation of methyl-hydroxylated derivatives of 7,12- dimethylbenz[a]anthracene by human liver dehydroepiandrosterone-steroid sulfotransferase

Methyl-hydroxylated metabolites of the potent carcinogen, 7,12- dimethylbenz[a]anthracene (DMBA), namely, 7-hydroxymethyl-12- methylbenz[a]anthracene (7-OH-DMBA), 7-methyl-12- hydroxymethylbenz[a]anthracene (12-OH-DMBA) and 7,12- dihydroxymethylbenz[a]anthracene (7,12-diOH-DMBA), were examined as substrates for sulfotransferase bioactivation in different human tissue cytosols. Hepatic cytosols, which were able to catalyze the 3'- phosphoadenosine 5'-phosphosulfate (PAPS)-dependent DNA binding of 7-OH- DMBA, 12-OH-DMBA and 7,12-diOH-DMBA, were highly sensitive to inhibition by dehydroepiandrosterone (DHEA), a specific substrate for human DHEA-steroid sulfotransferase (IC50 = 5 microM). By comparison, 2,6-dichloro-4-nitrophenol, a potent inhibitor of the thermostable (TS)- phenol and estrogen sulfotransferases, did not have an appreciable inhibitory effect. Neither p-nitrophenol, a high affinity substrate for human TS-phenol and estrogen sulfotransferases, nor dopamine, a specific substrate for the thermolabile (TL)-phenol sulfotransferase, significantly inhibited the DNA binding of 12-OH-DMBA catalyzed by hepatic cytosols. Inter-subject variation (n = 12) of the PAPS- dependent DNA binding of 12-OH- and 7,12-diOH-DMBAs also correlated well with DHEA-sulfotransferase activity (r = 0.90; P < 0.00001 and r = 0.92; P < 0.00001, respectively). This sulfation-dependent metabolic activation was not detected in cytosols from human colon, pancreas, larynx or mammary gland. Both TS- and TL-phenol sulfotransferases were active in human liver and colon but only liver contained DHEA- sulfotransferase activity. These results indicate that the sulfotransferase-mediated activation of the methyl-hydroxylated DMBAs is predominantly catalyzed by DHEA-steroid sulfotransferase in human liver and that TS- and TL-phenol sulfotransferases and estrogen sulfotransferase are not involved in the catalysis.