Prevalence and factors associated with knee osteoarthritis among middle-aged and elderly individuals in rural Tianjin: a population-based cross-sectional study.

BACKGROUND: The prevalence of osteoarthritis has been investigated in many countries and regions. Considering the wide differences in ethnicity, socioeconomic status, environmental factors, and lifestyle patterns, our study aimed to report the prevalence of knee osteoarthritis (KOA) and its associated factors in rural areas of Tianjin. METHODS: This population-based cross-sectional study was conducted between June and August 2020. KOA was diagnosed according to the 1995 American College of Rheumatology criteria. Information on participants' age, years of education, BMI, smoking and drinking status, sleep quality, and frequency of walking were collected. Multivariate logistic regression analysis was used to analyze factors influencing KOA. RESULTS: This study included 3924 participants (1950 male and 1974 female); the mean age of all participants was 58.53 years. In total, 404 patients were diagnosed with KOA, and the overall prevalence of KOA was 10.3%. The prevalence of KOA was higher in women than in men (14.1% vs. 6.5%). The risk of KOA in women was 1.764 times higher than that in men. The risk of KOA increased following the increasement of age. There was higher risk of KOA in participants who walked frequently than in participants who walked infrequently (OR = 1.572); in participants with overweight than in participants with normal weight (OR = 1.509), in participants with average sleep quality (OR = 1.677) and those with perceived poor sleep quality (OR = 1.978), respectively, than participants with satisfactory sleep quality, and in postmenopausal women than in non-menopausal women (OR = 4.12). The risk of KOA in participants with an elementary level was lower (0.619 times) than participants with illiteracy. In addition, the results of gender subgroup analysis showed that in male, age, obesity, frequent walking and sleep quality were independent factors associated with KOA; while in female, age, BMI, education level, sleep quality, frequent walking and whether menopausal were independent factors associated with KOA (P < 0.05). CONCLUSION: The results of our population-based cross-sectional study showed that sex, age, educational level, BMI, sleep quality, and frequent walking were independent influencing factors for KOA, and the influencing factors for KOA differed between the sexes. In order to reduce the disease burden of KOA and the harm to the health of middle-aged and elderly people, the risk factors related to the control of KOA should be identified as much as possible. TRIAL REGISTRATION: ChiCTR2100050140.

[Biomechanical research of less invasive stabilization system and dynamic condylar screw in fixing subtrochanteric fractures of femur].

OBJECTIVE: To compare the biomechanical characteristics of the less invasive stabilization system (LISS) and the dynamic condylar screw (DCS) in the fixation of subtrochanteric fractures of the femur so as to provide theoretical basis for choosing internal fixator in clinical application. METHODS: Twelve cadaveric human femurs (35-50 years old) were selected with similar proximal femur, excluding deformities, fractures, and other lesions. The twelve femur specimens were randomly divided into 2 groups, 6 specimens per group. An 1 cm gap of osteotomy model was made in the proximal femur up to 1 cm below the lesser trochanter to simulate a comminuted subtrochanteric fracture of femur, and the distal end was embedded with denture acrylic and liquid for denture acrylic. Fracture was fixed by LISS in group A, and was fixed by DCS in group B. The specimens were fixed on Instron-8874 servo-hydraulic mechanical testing machine in a single-leg standing position, and the axial compression test and dynamic fatigue test were carried out to compare the compressive strength and the strain distribution at both sides of the fracture line. RESULTS: Axial compression test: the strain values of the 2 strain gauges in group A were significantly smaller than those in group B (P < 0.01); the vertical down displacement of the femoral head in group A was significantly smaller than that in group B (P < 0.01) under the same load; when the load was 600 N, the axial rigidity of group A was (209.06 +/- 18.63) N/mm, which was significantly higher than that of group B [(65.79 +/- 7.26) N/mm] (t = 3.787, P = 0.004). Dynamic fatigue test: the vertical down displacement of the femoral head in group A was significantly smaller than that in group B in the same cyclic loading cycle (P < 0.01); when the vertical down displacement of the femoral head was 0.5 mm, the force and the cyclic loading cycles in group A were significantly larger than those in group B (P < 0.01). CONCLUSION: LISS, which has good mechanical stability, can meet the requirements for subtrochanteric fracture of femur fixation in biomechanics and anatomical structures. It can be proven that the LISS internal fixator is firmer than the DCS internal fixator by biomechanical comparison.

A role for Acp29AB, a predicted seminal fluid lectin, in female sperm storage in Drosophila melanogaster.

Females of many animal species store sperm for taxon-specific periods of time, ranging from a few hours to years. Female sperm storage has important reproductive and evolutionary consequences, yet relatively little is known of its molecular basis. Here, we report the isolation of a loss-of-function mutation of the Drosophila melanogaster Acp29AB gene, which encodes a seminal fluid protein that is transferred from males to females during mating. Using this mutant, we show that Acp29AB is required for the normal maintenance of sperm in storage. Consistent with this role, Acp29AB localizes to female sperm storage organs following mating, although it does not appear to associate tightly with sperm. Acp29AB is a predicted lectin, suggesting that sugar-protein interactions may be important for D. melanogaster sperm storage, much as they are in many mammals. Previous association studies have found an effect of Acp29AB genotype on a male's sperm competitive ability; our findings suggest that effects on sperm storage may underlie these differences in sperm competition. Moreover, Acp29AB's effects on sperm storage and sperm competition may explain previously documented evidence for positive selection on the Acp29AB locus.