Changing attentional demands in left hemispatial neglect.

Seven variations of a letter cancellation test were used to examine how varying attentional demands affect hemispatial neglect in patients with right hemisphere lesions. While the 14 targets always remained in the same location, the number of distractors (zero, nine, 28, or 82) as well as their complexity (one letter or nine different letters) were varied. The percentage of targets canceled in the left hemispace was linearly related to the number of distractors. There were no differences between the complexity conditions. In a second study, the same 14 targets were presented but the distractors (zero, 14, or 41) were all placed on the right. Increasing the number of distractors on the right increased neglect on both sides of the space. Taken together, these results suggest that, while the limited attentional resources of the left hemisphere are biased toward the right hemispace, the absence of contralateral attentional demands allows these resources to be directed ipsilaterally.     

Nutritional issues in pediatric inflammatory bowel disease.

Malnutrition, characterized by weight loss, growth failure and micronutrient depletion, are prominent features of inflammatory bowel disease (IBD) in the pediatric age group. Accurate evaluation of the patient's nutritional status and appropriate nutritional support, whether enteral or parenteral, constitute integral parts of the management of the growing child with IBD. Over the past two decades, a number of studies have supported the potential use of nutritional therapy to induce remission and to control disease activity in symptomatic Crohn's disease. More recently, preliminary studies on the use of dietary supplements of marine-oil-derived omega-3 fatty acids have also indicated a beneficial effect in IBD patients. In parallel with these clinical trials, scientific research has recently focused on the concept that specific dietary alterations can modulate the immune response. Components of the diet that may have particular relevance to mucosal immunity and the pathogenesis of IBD include polyunsaturated fatty acids, nucleotides, and amino acids such as glutamine and arginine. Future research in the interactions between specific nutrients and the immune system will likely increase our understanding of the causes of IBD, as well as enhance the development of novel nutritional therapies for IBD patients.     

荧光原位杂交技术分析人结肠菌群方法研究

建立荧光原位杂交技术分析人体内结肠菌群的方法。取受试者新鲜粪便 ,选用 5种特异性的 16SrRNA寡核苷酸探针 ,检测粪便样本收集后的保存时间、温度 ,离心条件及样本固定液存放时间对杂交计数结果的影响。结果建立最佳实验条件为 :粪便样本收集后应尽快在 4℃下保存 ,放置时间不要超过 12小时即作处理 ;样本的适宜离心条件为 70 0g 2分钟 ;样本用多聚甲醛固定后在 - 80℃下存放时间不要超过 5个月。该方法具有较好的稳定性 ,可以有效地检出个体之间结肠菌群的差异。