Specific detection of foot-and-mouth disease serotype Asia 1 virus by carboxyl-magnetic beads conjugated with single-domain antibody.

BACKGROUND: Immunomagnetic nanobead (IMNB) labeled with specific antibody, has been demonstrated to be useful for the capturing and detection of viruses. RESULTS: In this study, we developed an imunomagnetic bead based on carboxyl-magnetic beads (MNB) labeled with a single-domain antibody (sdAb) for capturing foot-and-mouth disease (FMD) Asia 1 virus. After magnetic separation, complexes of MNB-sdAb-virus were detected with either a sandwich ELISA or QDs-C5 probe under a fluorescence microscope, and the complexes were used as templates for extraction of total RNA for amplification of the VP1 or 3D gene fragments using RT-PCR and real-time RT-PCR. The Asia 1 VLPs were efficiently captured through IMNB with a high binding rate of 5.09 µg of antigen/µl of bead suspension. Moreover, this method has been successfully used to capture Asia 1 antigen in synthetic samples. CONCLUSION: Ultimately, a specific and highly sensitive capture FMDV Asia 1 tool has been established that has the potential to enhance the sensitivity and reliability when diagnosing FMDV Asia 1.

Characterization of single-domain antibodies against Foot and Mouth Disease Virus (FMDV) serotype O from a camelid and imaging of FMDV in baby hamster kidney-21 cells with single-domain antibody-quantum dots probes.

BACKGROUND: Foot-and-mouth disease (FMD) is a highly contagious disease that affects cloven-hoofed animals and causes significant economic losses to husbandry worldwide. The variable domain of heavy-chain antibodies (VHHs or single domain antibodies, sdAbs) are single-domain antigen-binding fragments derived from camelid heavy-chain antibodies. RESULTS: In this work, two sdAbs against FMD virus (FMDV) serotype O were selected from a camelid phage display immune library and expressed in Escherichia coli. The serotype specificity and affinity of the sdAbs were identified through enzyme-linked immunosorbent assay and surface plasmon resonance assay. Moreover, the sdAbs were conjugated with quantum dots to constitute probes for imaging FMD virions. Results demonstrated that the two sdAbs were specific for serotype O and shared no cross-reactivity with serotypes A and Asia 1. The equilibrium dissociation constant (KD) values of the two sdAbs ranged from 6.23 nM to 8.24 nM, which indicated high affinity to FMDV antigens. Co-localization with the sdAb-AF488 and sdAb-QD probes indicated the same location of FMDV virions in baby hamster kidney-21 (BHK-21) cells. CONCLUSIONS: sdAb-QD probes are powerful tools to detect and image FMDV in BHK-21 cells.

Effects of leisure activities and general health on the survival of older people: a cohort study in China.

Objective: This study aimed to examine the influence of physical and cognitive leisure activities on the survival of older adults in China, while also exploring the potential mediating and moderating effects of general health. Methods: This study utilized the China Longitudinal Healthy Longevity Survey (CLHLS) datasets spanning from 2008 to 2018, and 10,347 eligible participants were included. The primary study outcome was all-cause mortality, and independent variables included physical leisure activities (PLA), cognitive leisure activities (CLA), and self-rated general health. Three sets of covariates were adjusted, including socio-demographic characteristics, health behaviors, and health status. Results: The longest survival time was the older people participating in PLA & CLA (mean = 50.31 months), while those participating in neither exhibited the lowest (mean = 29.60 months). Significant differences in survival status were observed in different types of leisure activities participation (Log-rank test, Chi-square = 576.80, p < 0.001). Cox regression indicated that PLA (HR = 0.705, 95% CI: 0.651-0.764), CLA (HR = 0.872, 95% CI: 0.816-0.933), and the both PLA & CLA (HR = 0.700, 95% CI: 0.656-0.747) were protective factors for the survival. Additionally, general health significantly moderated the relationship between PLA and reduced mortality risk (Coefficient = -0.089, p = 0.042). While CLA indirectly influenced the survival through general health (Coefficient = -0.023, p < 0.001). For the older people participating in PLA and CLA, general health played mediating (Coefficient = -0.031, p < 0.001) and moderating (Coefficient = -0.026, p = 0.013) role in the relationship between leisure activities and survival. Conclusion: Leisure activities and self-rated general health were important predictors of survival of the older adults, and general health exhibited a mediator and moderator in the relationship between leisure activities and survival status.

[Clinical study of temperature contrast injection procedure in prevention of bone cement leakage during vertebroplasty].

OBJECTIVE: To observe the effect of temperature contrast injection procedure on prevention and reduction of bone cement leakage in vertebroplasty (PVP). METHODS: The clinical data of 42 patients(48 vertebral bodies) with osteoporotic vertebral compression fractures(OVCFs) treated from July 2014 to July 2018 were retrospectively analyzed. There were 19 males and 23 females, aged from 62 to 80 years old with an average of 72 years. The vertebral fracture segment was T8-L5, including 30 lumbar vertebrae and 18 thoracic vertebrae. The course of the disease ranged from 3 d to 2 months. Twenty cases (20 vertebral bodies) were treated by single vertebroplasty (group A) and 22 cases (28 vertebral bodies) were treated by temperature contrast injection procedure(group B). The operative time, amount of bone cement injection, VAS score at 3 days after surgery, leakage rate and refracture rate were compared between two groups. RESULTS: The operative time, amount of bone cement injection and VAS score at 3 days after surgery in group B were (40.05±7.78) min, (3.93±0.19) ml, (3.55±0.74) points, respectively, and in group A were(38.90±6.81) min, (4.03±0.24) ml, (4.05±1.00) points, there was no significant difference between two groups(P>0.05). The leakage rate in group B was lower than that in group A (9.1% vs 40.0%, P<0.05). The refracture rate in group B was 9.1%(2/22), in group A was 15.0%(3/20), there was no significant difference between two groups (P>0.05). CONCLUSIONS: Temperature contrast injection procedure is an effective method to reduce the bone cement leakage in vertebroplasty.