Communities of bacteria wrapped in self-generated extracellular polymeric matrix and attached to a solid surface are known as biofilm. Biofilm formation and development can be divided into three stages: adhesion of cells to a surface, reproduction of the cells, and dispersion of cells. The procedure, which surface-attached biofilm disperses bacterial cells into the environment to colonize new sites, is defined as biofilm dispersal. Biofilm dispersal is an essential stage of biofilm life cycle. It plays an important role in the transmission of bacteria. For many pathogenic bacteria, biofilm dispersal can transform bacteria in biofilm into planktonic state and promote the spread of infection. The formation of biofilm may increase the resistance of bacteria to antimicrobial agent and host defence response compared with planktonic cells. In the oral cavity, oral microorganism can attach to the surface of oral tissue and prosthesis to form biofilm. Dental caries and periodontal disease are oral chronic infections diseases of the oral tissue. The occurrence of them has a close relationship with biofilm. The mechanism of dispersal is a hot topic in recent years. Some agents which promote dispersal might be a therapeutic potential against biofilm infections. The clinical implication of dispersal agents and potential application are promising. This article reviews the dispersal-inducing agents of oral biofilms.
Bacteria ; Biofilms ; Dental Caries ; Humans

OBJECTIVETo explore the quantitative relationship between the intensity of psychosocial stress and the degree of overall health damages.

METHODSA multi-group case-control study was designed and implemented. The cases included two groups of out-patients (177) and in-patients (214) in a hospital in Jianyang city, and controls (587) were from the follow-up cohort in the same city. Three groups were studied on the following contents: general demographic characteristics, psychosocial factors and the degree of health damages including mental, physical, and social status. Major statistical analyses were as follows: ranks test, ANOVA, cluster analysis, multinomial logistic regression and ordered-logit regression.

RESULTSOrdered-logit regression model showed that the odds ratio of negative life-events on degree of health damages was 1.335 (P < 0.01). This result showed that there was a positive dose-effect relationship between the negative life-events score and overall health damages. The utility of social support to overall health had protective effect (OR = 0.513).

CONCLUSIONNegative life-events were the major risk factors to overall health, and there was a dose-effect relationship between negative events and health damages. Function of social support played a protective factor for health.

Analysis of Variance ; Case-Control Studies ; Cohort Studies ; Educational Status ; Health Status ; Humans ; Marital Status ; Social Class ; Stress, Psychological ; psychology

Objectives To study the effect of cadmium (Cd) on the proliferation and apoptosis of mouse spermatocyte (GC-2 spd) cells and explore the underlying molecular mechanism. Methods GC-2 spd cells were cultured with 0, 5, 10, 15, 20 and 30 μM CdCl2, respectively, for 24 hours. The cell viability and IC50 of Cd were estimated based on CCK-8 data. The apoptosis of GC-2 spd cells and cellular concentration of ROS were analyzed by flow cytometry after treatment of the cells with different concentrations of CdCl2 (0, 5, 10 μM) for 24 hours. The expression levels of JNK/c-Jun signaling pathway regulatory proteins, pro-apoptotic factor Bax and anti-apoptotic factor Bcl-2, were determined by Western blot. Results Cd inhibited the proliferation of GC-2 spd cells with IC50 value of 12.99 μM, 95% CI [11.95, 14.00]. Exposure to 5 and 10 μM CaCl2 resulted in increases in apoptosis and cellular ROS generation in a dose-dependent manner, which was statistically significant compared with the control (P < 0.05). Although there was no difference in the expression level of c-Jun (P > 0.05), the phosphorylation level of JNK and c-Jun in Cd group was highly increased as compared to the control (P < 0.05). In addition, Cd exposure significantly increased the expression of Bax protein but decreased the expression Bcl-2 protein (P < 0.05). Conclusions Cadmium induces GC-2 spd cell apoptosis by increasing concentration of ROS and regulating the JNK/c-Jun signaling pathway.