Adhesion Molecule Deficiencies and Their Clinical Significance

Adhesion molecules play a major role in the recruitment of neutrophils to the site of inflammation. Currently, two congenital hereditary Leukocyte Adhesion Deficiency (LAD) syndromes are recognized. LAD I is due to the absence of the β subunit of the integrin molecule, while LAD II is caused by a deficiency of Sialy1 Lewis X, the neutrophil ligand for selectins. Clinically, both syndromes are characterized by recurrent bacterial infections, more severe in LAD I. Developmental abnormalities (growth and mental retardation) constitute a prominent feature of LAD II and may be attributed to a general defect found in fucose metabolism in LAD II.

Neutrophil motility was found to be defective in both syndromes. Using activated umbilical endothelial cells, we showed that LAD I neutrophil do not bind to cells expressing ICAM-1, while LAD II cells do not bind to endothelial cells expressing E- or P-selectin. Skin window technique showed a marked decrease in margination in both syndromes. Using intravital microscopy we were able to show that the basic defect in LAD II is in the “rolling” phase, while in LAD I, firm adhesion and transmigration are defective. Studies of these two rare conditions emphasized the important in vivo roles of adhesion molecules in host defense mechanism.     

Adhesion Molecule Deficiencies and Their Clinical Significance

Adhesion molecules play a major role in the recruitment of neutrophils to the site of inflammation. Currently, two congenital hereditary Leukocyte Adhesion Deficiency (LAD) syndromes are recognized. LAD I is due to the absence of the β subunit of the integrin molecule, while LAD II is caused by a deficiency of Sialy1 Lewis X, the neutrophil ligand for selectins. Clinically, both syndromes are characterized by recurrent bacterial infections, more severe in LAD I. Developmental abnormalities (growth and mental retardation) constitute a prominent feature of LAD II and may be attributed to a general defect found in fucose metabolism in LAD II.

Neutrophil motility was found to be defective in both syndromes. Using activated umbilical endothelial cells, we showed that LAD I neutrophil do not bind to cells expressing ICAM-1, while LAD II cells do not bind to endothelial cells expressing E- or P-selectin. Skin window technique showed a marked decrease in margination in both syndromes. Using intravital microscopy we were able to show that the basic defect in LAD II is in the “rolling” phase, while in LAD I, firm adhesion and transmigration are defective. Studies of these two rare conditions emphasized the important in vivo roles of adhesion molecules in host defense mechanism.     

EGFR和KDR在胃癌组织中的表达及临床意义

探讨表皮生长因子受体（epidermal growth factor receptor,EGFR）和含激酶插入区受体（kinase-insert domain-containing receptor,KDR）的表达与胃癌临床病理特征的关系及其临床意义.应用免疫组织化学PV法,检测60例胃癌组织中EGFR和KDR的表达情况,并且分析其与临床病理特征的关系.胃癌组织中EGFR和KDR阳性表达率分别为48.3%（29/60）、63.3%（38/60）,二者的阳性表达与浸润深度、淋巴结转移、TNM分期相关（P〈0.05）,并且存在共表达现象,表达强度呈正相关（rs=0.664,P〈0.05）.EGFR和KDR在胃癌的进展中起协同作用,为靶向EGFR和KDR生物治疗制剂在胃癌生物治疗中的应用及联合应用提供了一定的理论依据.     

The Toxins of Helminthosporium maydis (Race T) : A Colorimetric Determination of the Toxins, Their Appearance in Culture and in Infected Plants

Host-specific toxins produced by Helminthosporium maydis, race T, are measured quantitatively by a chemical assay procedure involving reaction of the toxins with a sulfuric acidacetic anhydride reagent and measurement of the absorbance of the product at 330 nm. The assay was shown to measure total toxin concentrations after only limited fractionation of the culture medium. Using the assay it was possible to show that the highest amount of toxin per gram of fungus mycelium occurs early in the growth cycle of H. maydis. Toxins I, II, and V are the predominant toxins at these early times both in culture and in infected corn and wheat varieties. Some chromatographic and spectral properties of toxin V, a previously unreported toxin, are described. Since toxin V appears in culture prior to toxins I, II, III and IV, a precursor-product relationship can be suggested.