Selectin/ligand interaction plays an important role in such biological processes as inflammatory reaction, tumor metastasis, etc. External forces affect dissociation of receptor-ligand bonds. A novel approach, upon optical trap technique, was developed in this study to investigate the dissociation of P-selectin/PSGL-1 (P-Selectin Glycoprotein Ligand 1) bindings. Stiffness of optical trap was calibrated with laser power using a viscous drag method. While P-selectin and PSGL-1 molecules were functionally coated on surfaces of glass beads, respectively, the dissociation of interacting molecule bond was studied by measuring the rupture force distribution. It was found that most probable rupture force increased with loading rate at < 25 pN/s. These results complemented and validated the current theory at low loading rates.
Humans ; Membrane Glycoproteins ; chemistry ; Optics and Photonics ; instrumentation ; Protein Binding ; Protein Structure, Tertiary

OBJECTIVETo determine the prevalence, cause and distributions of blindness and poor vision in patients with leprosy.

METHODSAn epidemiological survey of blindness and poor vision among 1045 cases of leprosy was carried out in Taixing City of Jiangsu Province, China.

RESULTSThe prevalence of bilateral blindness was 7.67%, unilateral blindness 4.4%, bilateral poor vision of various degrees 9.28% and unilateral poor vision 5.84%. The prevalence of eye complications varied significantly among different groups of patients; females had a higher prevalence than males, multibacillary patients higher than paucibacillary patients, and in-patients higher than out-patients. Corneal disease was the most common cause of blindness in study groups, followed by iritic disease and cataract; while the main cause of poor vision was cataract, then corneal and iritic diseases. Treatable blindness accounted for 62.7% of the cases and treatable poor vision for 88.6% of the patients studied. 56.62% of cases with eye complications expressed their willingness to be treated.

CONCLUSIONSAlthough prevention and treatment of low vision and blindness in leprosy patients is very hard, it is necessary for doctors and medical workers to make clear of the factors to cause low vision and blindness, especially those in leprosy patients so that some measures for prevention and treatment of the disease could be taken accordingly.

Adult ; Aged ; Aged, 80 and over ; Blindness ; epidemiology ; etiology ; China ; epidemiology ; Female ; Humans ; Leprosy ; complications ; Male ; Middle Aged ; Prevalence ; Vision, Low ; epidemiology ; etiology