OBJECTIVEThis research aimed to detect the expression levels of ffh gene in Streptococcus mutans (S. mutans) UA159 under different pH conditions, analyze the effect of pH on the expression of ffh gene in S. mutans, and identify the factors regulating the ffh gene expression.

METHODSSamples of S. mutans were collected at different growth stages (4 h, 18 h) and pH values (pH 4.0-7.0). Fluorescence quantitative real-time polymerase chain reaction (qRT-PCR) was used to measure the relative mRNA expression and trend of the target gene ffh in S. mutans at different growth stages and pH values.

RESULTSqRT-PCR results showed that the ffh gene expression decreased along with pH at 4 h, but the expression increased with decreasing pH at 18 h. Under the same pH conditions, the ffh gene expression was significantly different between 4 h and 18 h (P < 0.05).

CONCLUSIONGrowth stage and pH value influenced the ffh gene expression in S. mutans.

Bacterial Proteins ; Gene Expression ; Gene Expression Regulation, Bacterial ; Hydrogen-Ion Concentration ; Streptococcus mutans

Objective To compare the clinical outcomes of palmaris longus tendon (PLT) and iliotibial tract fascia graft (ITFG) for coracoclavicular ligament (CCL) reconstruction combined with hook plate fixation in the treatment of acromioclavicular joint (ACJ) dislocation.Methods A retrospective study was conducted to evaluate the outcomes of 68 patients with ACJ dislocation of Rockwood type Ⅲ and above who had been treated in our department with CCL reconstruction using PLT or ITFG in addition to hook plate fixation from January 2008 to January 2014.They were 57 males and 11 females,with an average age of 36.1 years (range,from 19 to 55 years).The patients were divided into 2 groups according to their grafts used in CCL reconstruction:36 cases in PLT group and 32 in ITFG group.They were firstly treated with CCL reconstruction followed by hook plate fixation.The hook plates were removed at 6 months after operation.The acromioclavicular and coracoclavicular distances were measured on the postoperative anteroposterior radiographs of the injured shoulders.The outcomes were assessed at the final follow-ups according to Constant-Murley shoulder score and Karlsson criteria.The 2 groups were compatible without significant differences in preoperative general data (P ＞ 0.05).Results The 68 patients were followed up for an average of 18 months (range,from 16 to 22 months).The acromioclavicular and coracoclavicular distances measured in PLT group at 12 months after operation were significantly larger than those measured in ITFG group (P ＜ 0.05).At the final follow-ups,the Constant-Murley shoulder score (92.1 ±7.2) and Karlsson excellent to good rate (83.3％,30/36) in ITFG group were insignificantly higher than those in TIR group (88.3 ± 9.8;81.3％,26/32) (P ＞ 0.05).Conclusion In the treatment of ACJ dislocation of Rookwood type Ⅲ and above,CCL reconstruction using ITFG may lead to better radiographic outcomes than that using PLT,though the 2 grafts lead to similar functional recovery of the injured shoulders.

Background There is a lack of evidence on whether exposure to PM_2.5 and its constituents would affect the relationship between the dietary approaches to stop hypertension (DASH) and central obesity. Objective To investigate the effect of exposure to PM_2.5 and its constituents on the correlation between the DASH dietary pattern and the prevalence of central obesity. Methods The data were obtained from the baseline survey of the "Xinjiang Multi-Ethnic Natural Population Cohort Construction and Health Follow-Up Study" in Urumqi. A DASH score was calculated according to intake frequency of 8 food groups, and summed from intake frequency of recommended food groups scored from 1 to 5 from low to high, and intake frequency of restricted food groups scored from 1 to 5 from high to low. A higher DASH score indicates better compliance with the DASH dietary pattern. We estimated exposure using satellite-derived PM_2.5 and a chemical transport model (GEOS-Chem) for its constituents, including organic carbon (OC), black carbon (BC), sulfate (SO₄²⁻), nitrate (NO₃⁻), ammonium (NH₄⁺), and soil dust. Central obesity was defined by waist circumference: ≥90 cm for men or ≥85 cm for women according to Criteria of weight for adults (WS/T 428—2013). A logistic regression model was used to analyze the effects of the DASH dietary pattern as well as PM_2.5 and its constituents on central obesity, and a stratified analysis was used to explore the effects of PM_2.5 and its constituents on the association between the DASH dietary pattern and central obesity. Results The study included 9 565 urban residents, aged (62.30±9.42) years, with a central obesity prevalence rate of 60.75%. After adjusting for selected confounders, the DASH score Q5 group had a 17.5% lower risk of central obesity than the Q1 group (OR=0.825, 95%CI: 0.720-0.947). PM_2.5 and its constituents OC, BC, SO₄²⁻, NH₄⁺, and soil dust were positively associated with the prevalence of central obesity, but no association was observed between constituent NO₃⁻ exposure and central obesity. The stratified analysis revealed that the prevalence of central obesity was reduced in the DASH score Q5 group in participants exposed to low concentrations of PM_2.5 and its constituents NO₃⁻, NH₄⁺, and soil dust, while the protective effect of the DASH pattern on central obesity disappeared in subjects exposed to high concentrations of PM_2.5 and its constituents NO₃⁻, NH₄⁺, and soil dust. Conclusion Exposure to PM_2.5 and its constituents NO₃⁻, NH₄⁺, and soil dust could attenuate the protective effect of the DASH pattern on central obesity.