RESUMO
Objective: To analyze the relationship between health belief and the stages of parental decision-making on childhood 13-valent pneumococcal conjugate vaccine (PCV13) immunization in China. Methods: Cross-sectional multistage survey sampling method was used to select study subjects. The study subjects were parents who were aged 20-45 years and had one and more children ≤5 years old in three cities in China. A self-administered questionnaire designed based on health belief model was used to collect the information. Multinomial logistic regression analysis was used to assess the relationships between perceived susceptibility, perceived severity of illness, perceived effect of PCV13 and stages of parental decision-making on childhood PCV13 immunization. Results: A total of 1 716 valid questionnaires were returned (89.33%). The average age of the study subjects was (35.33±4.95) years, and 79.60% of them were women. In the study subjects, 48.31% had in action, 21.79% were in contemplation and 29.90% were in pre-contemplation. The multinominal logistic regression analysis indicated that high perceived susceptibility (OR=0.14, 95%CI:0.09-0.22; OR=0.54, 95%CI:0.39-0.76), high perceived severity of illness (OR=0.55, 95%CI:0.42-0.73), and high perceived effect of PCV13 (OR=0.27, 95%CI:0.18-0.40; OR=0.51, 95%CI:0.32-0.81) were significantly lower in those who were in contemplation or pre-compared with those who had in action. For study subjects with low perceived susceptibility, high perceived effect of PCV13 might decrease the probabilities of contemplation (OR=0.53, 95%CI:0.32-0.87) and pre-contemplation (OR=0.27, 95%CI:0.18-0.41). For those with high perceived susceptibility, perceived severity of illness might decrease the probability of contemplation (OR=0.43, 95%CI:0.23-0.82). Conclusions: Childhood PCV13 vaccination willingness and level is low in China. It is important to pay greater attention to the intervention on health belief in child parents, such as perceived effect of PCV13, perceived severity of illness, and perceived susceptibility, in health policy development and health promotion.
Assuntos
Tomada de Decisões , Pais , Vacinas Pneumocócicas , Humanos , China , Pais/psicologia , Vacinas Pneumocócicas/administração & dosagem , Estudos Transversais , Adulto , Feminino , Inquéritos e Questionários , Masculino , Pessoa de Meia-Idade , Pré-Escolar , Vacinação/psicologia , Vacinação/estatística & dados numéricos , Vacinas Conjugadas/administração & dosagem , Conhecimentos, Atitudes e Prática em Saúde , Adulto Jovem , Infecções Pneumocócicas/prevenção & controleRESUMO
The adhesion of sickle erythrocytes to the vascular endothelium and subendothelial matrix probably contributes to the pathogenesis of vaso-occlusive disease. The chemotherapeutic agent hydroxyurea (HU) decreases the frequency of vaso-occlusive crises in patients with sickle cell disease. However, the exact mechanism(s) of HU's effect on vaso-occlusive crises is not fully understood. The goal of this study was to determine the effect of HU therapy on the adhesion of sickle erythrocytes to the subendothelial matrix proteins thrombospondin (TSP) and laminin under conditions of flow in vitro. Erythrocytes from patients with severe sickle cell disease on HU therapy (n = 14) had significantly less adhesion to TSP (687 +/- 92 erythrocytes/mm2, mean +/- SE) than untreated patients with severe disease (n = 18, 1176 +/- 117 erythrocytes/mm2, P = 0.003). In addition, there was significantly less adhesion of erythrocytes to immobilized laminin in patients treated with HU (1695 +/- 293 erythrocytes/mm2) than in the untreated patients (2590 +/- 296 erythrocytes/mm2, P = 0.02). Erythrocytes from an additional nine patients with severe sickle cell disease were studied both before and after initiation of HU therapy. Erythrocytes from these patients became less adhesive to both TSP (P = 0.001) and laminin (P = 0.01), a change that was sustained in most patients throughout the duration of the study (2 months to > 12 months). This study suggests that HU modulates the adhesive phenotype of sickle erythrocytes, an effect that may be in addition to, or independent of, other known effects of HU, such as an increase in fetal haemoglobin level.
Assuntos
Antidrepanocíticos/farmacologia , Eritrócitos/patologia , Hidroxiureia/farmacologia , Laminina/metabolismo , Traço Falciforme/patologia , Trombospondinas/metabolismo , Adolescente , Adulto , Adesão Celular/efeitos dos fármacos , Células Cultivadas , Criança , Feminino , Humanos , Masculino , Traço Falciforme/metabolismoRESUMO
Sickle red blood cells (SS-RBCs) have enhanced adhesion to the plasma and subendothelial matrix protein thrombospondin-1 (TSP) under conditions of flow in vitro. TSP has at least four domains that mediate cell adhesion. The goal of this study was to map the site(s) on TSP that binds SS-RBCs. Purified TSP proteolytic fragments containing either the N-terminal heparin-binding domain, or the type 1, 2, or 3 repeats, failed to sustain SS-RBC adhesion (<10% adhesion). However, a 140-kD thermolysin TSP fragment, containing the carboxy-terminal cell-binding domain in addition to the type 1, 2, and 3 repeats fully supported the adhesion of SS-RBCs (126% +/- 25% adhesion). Two cell-binding domain adhesive peptides, 4N1K (KRFYVVMWKK) and 7N3 (FIRVVMYEGKK), failed to either inhibit or support SS-RBC adhesion to TSP. In addition, monoclonal antibody C6. 7, which blocks platelet and melanoma cell adhesion to the cell-binding domain, did not inhibit SS-RBC adhesion to TSP. These data suggest that a novel adhesive site within the cell binding domain of TSP promotes the adhesion of sickle RBCs to TSP. Furthermore, soluble TSP did not bind SS-RBCs as detected by flow cytometry, nor inhibit SS-RBC adhesion to immobilized TSP under conditions of flow, indicating that the adhesive site on TSP that recognizes SS-RBCs is exposed only after TSP binds to a matrix. We conclude that the intact carboxy-terminal cell-binding domain of TSP is essential for the adhesion of sickle RBCs under flow conditions. This study also provides evidence for a unique adhesive site within the cell-binding domain that is exposed after TSP binds to a matrix.
Assuntos
Anemia Falciforme/patologia , Eritrócitos/patologia , Trombospondinas/metabolismo , Aminoácidos , Anemia Falciforme/sangue , Sítios de Ligação/genética , Adesão Celular , Eritrócitos/metabolismo , Humanos , Análise de Sequência , Trombospondinas/genéticaRESUMO
Red blood cell (RBC) adhesion to the vascular endothelium is increased in several pathologic conditions, including sickle cell disease and malaria. However, RBC interactions with components of the subendothelial matrix are not well-characterized. Under in vitro flow conditions of 1 dyne/cm2, washed RBCs bound to the purified adhesive molecules thrombospondin (TSP) and laminin. Sickle RBCs had the greatest adhesion of all tested RBCs. The adhesion of sickle RBCs to immobilized TSP was inhibited by the anionic polysaccharides high molecular weight (MW) dextran sulfate and chondroitin sulfate A, but not other anionic polysaccharides of similar structure and/or charge density. These data were consistent with the RBC adhesive molecule being a sulfated glycolipid. Therefore, TSP-binding lipids from normal and sickle RBCs were isolated and characterized. The TSP-binding lipid was purified by alkaline methanolysis, anion exchange chromatography and preparative thin layer chromatography (TLC). A homogeneous band on TLC was identified using a specific overlay TSP-binding assay. TSP binding to the purified lipid was stable to bass and neuraminidase treatment, labile to acid treatment, and was inhibited by high MW dextran sulfate, similar to that seen with intact RBCs binding to immobilized TSP under conditions of flow. In addition, soluble laminin bound to the purified RBC lipid. This acidic TSP- and laminin-binding lipid(s) isolated from both sickle and normal RBC membranes may contribute to erythrocyte interactions with the subendothelial matrix, hereby participating in the pathogenesis of vaso-occlusive diseases.