Pleuropulmonary melioidosis in a Cambodian refugee.

A 47-year-old Cambodian refugee presented with an acute respiratory illness that featured consolidation of the lower lobe of the left lung and progressive involvement of the adjacent pleura caused by Pseudomonas pseudomallei. Initial difficulty in identifying the organism resulted in an inadequate duration of therapy. Chronic pleural disease followed, and the organism became resistant to many antibiotics during therapy. A diagnosis of pleuropulmonary melioidosis should be entertained and the microbiology laboratory alerted when patients with pneumonia who are from endemic areas are encountered, so that a diagnosis can be made early and the appropriate treatment begun.     

An overview of models of stomatal conductance at the leaf level

Stomata play a key role in plant adaptation to changing environmental conditions as they control both water losses and CO₂ uptake. Particularly, in the context of global change, simulations of the consequences of drought on crop plants are needed to design more efficient and water‐saving cropping systems. However, most of the models of stomatal conductance (g_s) developed at the leaf level link g_s to environmental factors or net photosynthesis (A_net), but do not include satisfactorily the effects of drought, impairing our capacity to simulate plant functioning in conditions of limited water supply. The objective of this review was to draw an up‐to‐date picture of the g_s models, from the empirical to the process‐based ones, along with their mechanistic or deterministic bases. It focuses on models capable to account for multiple environmental influences with emphasis on drought conditions. We examine how models that have been proposed for well‐watered conditions can be combined with those specifically designed to deal with drought conditions. Ideas for future improvements of g_s models are discussed: the issue of co‐regulation of g_s and A_net; the roles of CO₂, absissic acid and H₂O₂; and finally, how to better address the new challenges arising from the issue of global change.     

Evolution of xyloglucan-related genes in green plants

Background  

The cell shape and morphology of plant tissues are intimately related to structural modifications in the primary cell wall that are associated with key processes in the regulation of cell growth and differentiation. The primary cell wall is composed mainly of cellulose immersed in a matrix of hemicellulose, pectin, lignin and some structural proteins. Xyloglucan is a hemicellulose polysaccharide present in the cell walls of all land plants (Embryophyta) and is the main hemicellulose in non-graminaceous angiosperms.     

Recurrent aphthae: treatment with vitamin B12, folic acid,and iron.

A series of 130 consecutive outpatients with recurrent aphthous stomatitis were screened at the oral medicine department, Glasgow Dental Hospital, for deficienciesin vitamin b12, folic acid, and iron. In 23 patients (17.7%) such deficiencies werefound; five were deficient in vitamin B12, seven in folic acid, and 15 in iron. Four had more than one deficiency. Out of 130 controls matched for age and sex 11 (8.5%) were found to have deficiencies. The 23 deficient patients with recurrent aphthaewere treated with specific replacement therapy, and all 130 patients were followed up for at least one year. Of the 23 patients on replacement therapy 15 showed complete remission of ulceration and eight definite improvement. Of the 107 patientswith no deficiency receiving local symptomatic treatment only 33 had a remission or wereimproved. This difference was significant (P less than 0.001). Most patients withproved vitamin B12 or folic acid deficiency improved rapidly on replacement therapy;those with iron deficiency showed a less dramatic response. The 23 deficient patientswere further investigated to determine the cause of their deficiencies and detect the presence of any associated conditions. Four were found to have Addisonian perniciousanaemia. Seven had a malabsorption syndrome, which in five proved to be a gluten-induced enteropathy. In addition, there were single patients with idiopathic proctocolitis, diverticular disease of the colon, regional enterocolitis, and adenocarcinoma of thecaecum. We suggest that the high incidence of deficiencies found in this series andthe good response to replacement therapy shows the need for haematological screening of such patients.     

Structural requirements of carbohydrates to bind Agaricus bisporus lectin

Galbeta1-3GalNAc (T-disaccharide) and related molecules were assayed to describe the structural requirements of carbohydrates to bind Agaricus bisporus lectin (ABL). Results provide insight into the most relevant regions of T-disaccharide involved in the binding of ABL. It was found that monosaccharides bind ABL weakly indicating a more extended carbohydrate-binding site as compared to those involvedin the T- disaccharide specific lectins such as jacalin and peanut agglutinin. Lacto-N-biose (Galbeta1-3GlcNAc) unlike T-disaccharide, is unable to inhibit the ABL interaction, thus showing the great importance of the position of the axial C-4 hydroxyl group of GalNAc in T-disaccharide. This finding could explain the inhibitory ability of Galbeta1-6GlcNAc and lactose because C-4 and C-3 hydroxyl groups of reducing Glc, respectively, occupy a similar position as reported by conformational analysis. From the comparison of different glycolipids bearing terminal T-disaccharide bound to different linkages, it can be seen than ABL binding is even more impaired by an adjacent C-6 residual position than by the anomeric influence of T-disaccharide. Furthermore, the addition of beta-GlcNAc to the terminal T-disaccharide in C-3 position of Gal does not affect the ABL binding whereas if an anionic group such as glucuronic acid is added to C-3, the binding is partially affected. These findings demonstrate that ABL holds a particular binding nature different from that of other T-disaccharide specific lectins.      

脂多糖通过补体途径诱导小鼠产生白三烯B4

目的:研究脂多糖(LPS)对人血清中补体系统的激活及在小鼠模型中诱导产生白三烯B4(LTB4)。方法:LPS包被ELISA板,利用血清中补体C4、C3沉积实验检测补体成分被LPS活化的情况,通过尾静脉注射小鼠LPS后不同时间点ELISA定量检测LTB4,评价补体系统的活化和炎症因子的产生。结果与结论:血清系统ELISA检测发现LPS可以激活补体系统,且以凝集素途径为主;动物实验中LTB4被LPS诱导后1～3 h达到峰值,之后回落。C1INH对血清补体活化和动物模型中LTB4的产生均有显著抑制。