Human coagulation factor VIII domain-specific recombinant polypeptide expression

BACKGROUND: Hemophilia A is caused by heterogeneous mutations in F8. Coagulation factor VIII (FVIII), the product of F8, is composed of multiple domains designated A1-A2-B-A3-C1-C2. FVIII is known to interact with diverse proteins, and this characteristic may be important for hemostasis. However, little is known about domain-specific functions or their specific binding partners. METHODS: To determine F8 domain-specific functions during blood coagulation, the FVIII domains A1, A2, A3, and C were cloned from Hep3B hepatocytes. Domain-specific recombinant polypeptides were glutathione S-transferase (GST)- or polyhistidine (His)-tagged, over-expressed in bacteria, and purified by specific affinity chromatography. RESULTS: Recombinant polypeptides of predicted sizes were obtained. The GST-tagged A2 polypeptide interacted with coagulation factor IX, which is known to bind the A2 domain of activated FVIII. CONCLUSION: Recombinant, domain-specific polypeptides are useful tools to study the domain-specific functions of FVIII during the coagulation process, and they may be used for production of domain-specific antibodies.

The Effects of Stressors on Subjective Well-Being in the Elderly

OBJECTIVE: This study aims to identify self-reported stressors in the Korean community-dwelling elderly and examine their effects on subjective well-being. METHODS: The subjects of this research were 1,010 elderly people who lived in Suwon, Korea. Each subject was administered the questionnaires regarding the socio-demographic characteristics, self-reported stressors, Concise Measure of Subjective Well-Being (COMOSWB) consisting of life satisfaction, positive emotion and negative emotion, Mini-Mental State Examination for dementia screening and Short Form Geriatric Depression Scale-Korean version. Statistical analyses including the Pearson's correlation test and multiple linear regressions were performed in this study. RESULTS: In our adjusted model for confounding variables, stress from physical problems (S-PP) (ss=-0.133, p<0.001), stress from loneliness or solitude (S-LS) (ss=-0.077, p=0.007), stress from family members (S-FM) (ss=-0.083, p=0.001) were negatively associated with the total score of COMOSWB. In subscale analyses of COMOSWB, we also found that S-PP (ss=-0.184, p<0.001), S-LS (ss=-0.077, p=0.014), stress from economic problems (ss=-0.072, p=0.021) were negatively associated with life satisfaction score. While S-PP (ss=-0.140, p<0.001) and S-FM (ss=-0.079, p=0.003) were negatively associated with positive emotion score, S-FM (ss=0.105, p=0.001) and stress from friends and neighbors (ss=0.072, p=0.016) were positively associated with negative emotion score. CONCLUSION: Stresses from physical problems, loneliness, and family members might be associated with subjective well-being in the elderly. While life satisfaction appears to be affected by one's perceived physical health status, loneliness, and economic conditions, positive and negative emotions appear to be affected by relationships with family members, friends, or neighbors.