Objective To observe the dynamic changes of high mobility group protein B1 ( HMGB1 )expression in the lung of rats with Vibrio vulnificus sepsis so as to unravel the role of HMGB1 in lung injury.Methods Sixty rats of clean grade were randomly divided into normal control group ( A group, n = 10) and Vibrio vulnificus sepsis group (B group, n =50). Sepsis model was made in rats with subcutaneous injection of Vibrio vulnificus with concentration of 6 × 108 cfu/ml in dose of 0. 1 ml/100 g into left lower limb.The rats of group B were sacrificed 1 h, 6 h, 12 h, 24 h and 48 h after infection for taking lung tissues to detect the water content of lung and to observe the histopathological changes in lung under light microscope.The expression of HMGB1 mRNA and the level of HMGB1 protein in the lungs were detected by RT-PCR and Western blot, respectively. Data were analysed with ANOVA and LSD method for comparison between groups, and P ＜0.05 was considered statistically significant. Results Compared with the group A (0.652±0. 177), the expressions of HMGB1 mRNA in lung of rats of group B were significantly higher in 12 hours (1. 161 ±0.358, P=0.013), 24 hours (1.679 ±0.235, P =0.000) and 48 hours (1.258 ±0.274, P=0.004) and reached the peak in 24 h. Compared with group A (0.594 ±0. 190), the level of HMGB1 protein in rats of group B 6 h after infection ( 1. 408 ± 0. 567, P = 0. 026) was significantly increased (P＜0.05), and it reached peak in 24 h (2.415 ± 1.064, P =0.000) after infection. Compared with group A (0.699 ± 0.054), the lung water contents in rats of group B were significantly increased in 6 h (0.759±0.030, P=0.001), in 12 h (0.767 ±0.023, P =0.000), in 24 h (0.771 ±0.043, P=0.000) and in 48 h (0.789 ±0.137, P=0.000) after infection. Compared with group A, the pathological changes in the lung of rats in group B showed clearly marked pulmonary vascular congestion, interstitial edema and inflammatory cell infiltration, and those changes became more and more serious until alveolar sacs entirely collapsed and the boundaries of the alveolar septa could not be clearly identified in 48 h. Conclusions Vibrio vulnificus sepsis leads to the lung injury of infected rats, and the increase in the expression of HMGB1 mRNA in lung might be one of the mechanisms of lung injury in rats with Vibrio vulnificus sepsis.

Objective:To record occlusal contact of primary dentition at maximal intercuspal position in children with individual normal occlusion.Methods:A total of 57 children were recruited from patients of the Department of Pediatric Dentistry, Peking University School and Hospital of Stomatology. Inclusion criteria were that the subjects were 3-5 years old with no visually detectable caries or pupal and periapical diseases, had complete primary dentition, had individual normal occlusion, had normal function of craniofacial system, were medically healthy, could cooperate with sampling and had obtained written informed consent from the parents or guardians. Finally, forty-seven children aged 3 to 5 years old were enrolled, including 24 males and 23 females. The age, height and weight of all subjects were (4.1±0.7) years old (ranging 3.0-5.8 years old), (103.7±7.2) cm (ranging 90-120 cm) and (17.1±2.5) kg (ranging 12.5-22.5 kg), respectively. Occlusal abilities such as occlusal contact area, average bite pressure, maximum bite pressure, maximum bite force and occlusal balance were measured with Dental Prescale Ⅱ system.Results:Maximum bite force and occlusal contact area at intercuspal position in children with primary dentition were (567.40±223.84) N (ranging 226.7-1 154.6 N) and (18.56±6.54) mm 2 (ranging 8.4-41.2 mm 2), respectively. There was a significantly strong correlation between maximum bite force and occlusal contact area ( r=0.954, P<0.01). Height and weight of children were also positively correlated with their maximum bite force ( r=0.397, P=0.022 and r=0.453, P=0.008, respectively). Maximum occlusal bite force and contact occlusal area of boys [(651.80±224.34) N and (20.77±6.97) mm 2] were significantly higher and larger than those of girls [(479.34±190.45) N and (16.25±5.27) mm 2] ( P<0.05). Thirty-two of all 47 children had one occlusal contact point with maximum bite pressure, mostly locating within the primary molar region. Bite forces of anterior and posterior teeth of primary dentition were (124.12±56.99) N and (450.11±205.09) N, respectively, about (21.82±11.40)% and (71.80±21.35)% of maximum bite force of the whole primary dentition. All of the occlusal balance points located in posterior teeth regions. Occlusal contacts were observed at both anterior and posterior teeth of primary dentition with individual normal occlusion. Conclusions:There was a great variation of maximum bite forces of primary dentitions at intercuspal position of children with individual normal occlusion. Maximum bite force of primary dentition was significantly correlated with occlusal contact area, height and weight of children. Occlusal contact points with maximum bite pressure and occlusal bite balance points of primary dentitions mostly located in primary molar regions.