Objective:To investigate the relationship between the removal time of 0.2 mm occlusal in-terference and the recovery of masticatory muscle mechanical hyperalgesia in rats.Methods:Forty male Sprague-Dawley rats (200-220 g)were randomly assigned to eight groups,with five rats in each group:(1 )nave group:these rats were anesthetized and their mouths were forced open for about 5 min (the same duration as the other groups),but restorations were not applied;(2 )sham-occlusal interference control group:bands were bonded to the right maxillary first molars which did not interfere with occlu-sion;(3 )occlusal interference group:0.2 mm thick crowns were bonded to the right maxillary first molars;(4)2,3,4,5,and 6 d removal of occlusal interference groups:0.2 mm thick crowns were bonded to the right maxillary first molars and removed on days 2,3,4,5,and 6.The nave group and sham-occlusal interference control group were control groups.The other groups were experimental groups. Bilateral masticatory muscle mechanical withdrawal thresholds were tested on pre-application days 1 ,2, and 3,and on post-application days 1 ,3,5,7,1 0,1 4,21 and 28.The rats were weighed on pre-application day 1 and on post-application days 1 ,2,3,4,5,6,and 7.Results:Between the nave group and the sham-occlusal interference control group,there was no significant difference in the mastica-tory muscle mechanical withdrawal threshold of bilateral temporalis and masseters at each time point.No significant difference was detected between the contralateral side and ipsilateral side in experimental groups (P>0.05 ).In the 2,3,4,and 5 d removal of occlusal interference groups,the masticatory muscle mechanical withdrawal thresholds decreased after occlusal interference and increased after removal of the crowns and recovered to the baseline on days 7,1 0,1 4,and 1 4,respectively [the masticatory muscle mechanical withdrawal thresholds of right masseter muscle were (1 37.46 ±2.08)g,(1 39.02 ± 2.1 1 )g,(1 40.40 ±0.98)g,(1 38.95 ±0.98)g,respectively].In the 6 d removal of occlusal inter-ference group,the masticatory muscle mechanical withdrawal threshold increased after removal of the crowns and became stable since day 1 4.There was a significant difference between the 6 d removal of oc-clusal interference group and the sham-occlusal interference group on day 28(P<0.05),the masticatory muscle mechanical withdrawal thresholds of right masseter muscle were (1 31 .24 ±0.76 ) g and (1 41 .34 ±1 .43)g,respectively.Conclusion:After removal of the 0.2 mm thick crown within 5 days, the mechanical hyperalgesia of the rats could reverse completely.The mechanical hyperalgesia of the rats could only be relieved,but not reverse completely after removal of the 0.2 mm thick crown on day 6.As the time went on,even minor occlusal interference could cause irreversible mechanical hyperalgesia of masticatory muscles.This study suggested that occlusal interference caused by dental treatment should be eliminated as soon as possible,to avoid irreversible orofacial pain.

Objective: To study the chemical constituents of the flowers of Impatiens balsamina L.. Methods: The compounds were isolated by chromatography and solvant extration and the structures were identified on the basis of spectral analysis. Results: Four compounds were isolated and identified as stigmasterol(1), kaempferol(2), Kaempferol 3 glucoside(3) and Kaempferol 3 glucosyl rhamnoside(4). Conclusions: All the compounds were isolated from the flowers which were cultured for the first time in China.

The threats to human health caused by climate change have become a global public health issue. However, at present, most studies regarding the health-related mechanisms of climate change are limited to biological mechanisms, and most of these mechanisms are not totally clear. In this special column: Mechanisms underlying human health effects of climate change, we offered several papers which investigated the effects of different meteorological factors (temperature and rainfall) on various health outcomes (preterm birth, death, diarrhea, infectious diseases, etc.), and also elaborated associated potential biological mechanisms, vulnerability mechanisms, social driving process and transmission dynamics mechanisms. These studies can deepen our understanding of the health effects of climate change, provide references to make targeted adaptative measures, and also provide scientific and technological supports for improving ability to address the health risks of climate change in China.

Infectious diarrhea is an important public health problem, which has a significant impact on global disease burden. Under the background of climate change, rainstorms increase and floods occur frequently. Most studies show that the incidences of infectious diarrhea disease increase significantly after rainstorm and flood events. However, there is a lack of systematic summary on the path of rainstorm and flood events affecting the incidence of infectious diarrhea, including the key links and mechanisms underlying environmental-social interaction. This study comprehensively combed the literature from environmental factors, socio-economic and cultural factors, and population and individual susceptibility factors. The potential mechanisms of infectious diarrhea caused by rainstorm and flood events were discussed from the aspects of spreading of pathogens, affecting sanitation facilities and (or) drinking water treatment infrastructure, the regulatory role of individual and behavioral factors, and long-term effects. Based on the "pressure-state-response" model, a social driving process model of rainstorm and flood leading to incidence of infectious diarrhea was constructed. This model could provide reference for future quantitative modeling and other research directions. It is helpful to guide the public health departments to accurately identify factors affecting the incidence of infectious diarrhea after rainstorm and flood, so as to take targeted intervention measures.

Background Climate change has resulted in long-term impacts on human health. Implementing efficient adaptation strategies among primary healthcare facilities is well determined by whether staff of different genders recognize the health risks related to climate change and are willing to take active measures. Objective To investigate gender differences on perceptions of health risks and attitude towards adaptation strategies among primary healthcare workers in China, and provide relevant suggestions. Methods By adopting a multi-stage cluster sampling method, we selected 21 urban and 10 rural healthcare facilities in Guangdong Province to collect information with a questionnaire. Then chi-square test, Wilcoxon rank sum test, and logistic regression analysis were used to explore the gender differences in climate change-related health risk cognition, knowledge acquisition channels, attitudes towards adaptation strategies, main obstacles, and resource requirements among the healthcare workers. Results Of 733 participants, 38.47% (282 participants) were male and 61.53% (451 participants) were female. The percentages of male healthcare workers who agreed that climate change is happening and recognized the causes of climate change (70.21%, 60.99%) were higher than the percentages of female counterparts (59.87%, 49.00%) (both Ps＜0.05), but no obvious gender differences existed in recognizing health risks of heatwaves and infectious diseases as well as sensitive population identification (all Ps＞0.05). Most of the participants (92.50%) received climate change and health-related information from mass media like TV, radio, and newspapers. Meanwhile less men chose new media channels than women (OR=0.62, 95%CI∶ 0.41-0.94). Only 30.56% of the participants (33.69% of men and 28.60% of women) reported involvement of relevant training and lectures. Most of them (90.96%) agreed to take active measures to deal with the health threats associated with climate change without gender differences for various measures (all Ps＞0.05). The leading obstacles were hard to integrate health adaptation to climate change into main work of institutions (most female agreed, 72.28%) and the lack of funds (most male agreed, 77.66%). Increasing funding for primary health care was regarded as the most needed resource by male (86.88%) and female (89.14%). After controlling the influence of other social factors, more men agreed with the lack of funds than women (OR=1.57, 95%CI∶ 1.10-2.24). Conclusion There are some gender differences in the perceptions of health risks and adaptation strategies of climate change among primary healthcare workers: Male staff are more likely to agree with climate change and regard the lack of funds as the main obstacle, while women prefer to choose new media channels to obtain information. It’s suggested that the government and relevant institutions focus on the learning and training of climate change and health-related knowledge and expand diversified information access, and promote capacity building to cope with health threats at grass-root level, in the light of recognized gender differences among primary healthcare workers.

Background Climate change leads to frequent heavy rainfall events, and higher incidences of bacillary dysentery after heavy rainfall have been observed. The impacts of heavy rainfall and its antecedent rainfall conditions on the disease are worth paying attention to. Objective To quantitatively analyze how the relationship between heavy rainfall events and bacillary dysentery occurrence is modified by antecedent rainfall conditions in Anhui Province and explore the different moderation effects in urban and rural contexts. Methods CN05.1 meteorological data of Anhui Province and cases of bacillary dysentery of the same area were collected from January 1, 2006 to August 31, 2017. An exposure-response Poisson regression model of heavy rainfall events and the number of daily cases was constructed to explore the moderation effect of antecedent rainfall conditions on the incidence of bacillary dysentery, and further stratified by urban and rural areas. Results This study included 129 459 cases of bacillary dysentery, with a daily average of 30.39. Compared with dry antecedent conditions without heavy rainfall, dry antecedent conditions with heavy rainfall had no obvious different effect on the incidence of bacillary dysentery for the whole province (P>0.05). But wet antecedent conditions significantly increased the risk of bacillary dysentery for the whole province after heavy rainfall (wet antecedent conditions without heavy rainfall: RR=1.281, 95%CI: 1.264-1.298; wet antecedent conditions with heavy rainfall: RR=1.267, 95%CI: 1.167-1.376). After urban and rural stratification, antecedent rainfall conditions also showed a significant moderation effect on the incidence of bacillary dysentery following heavy rainfall events. Compared with dry antecedent conditions without heavy rainfall, dry antecedent conditions with heavy rainfall had no obvious effect on the incidence of bacillary dysentery for the urban and the rural populations (P > 0.05). However, wet antecedent conditions without heavy rainfall (urban: RR=1.391, 95%CI: 1.362-1.421; rural: RR=1.222, 95%CI: 1.201-1.243) and wet antecedent conditions with heavy rainfall (urban: RR=1.364, 95%CI: 1.193-1.559; rural: RR=1.218, 95%CI: 1.098-1.352) significantly increased the risk of bacillary dysentery in both rural and urban areas. Conclusion In the influence of heavy rainfall on the incidence of bacillary dysentery in Anhui Province, antecedent rainfall conditions have a certain moderation effect in the whole province and in both urban and rural areas, and the risk of bacillary dysentery is increased under wet antecedent conditions.

Objective: To investigate the morphological changes in microglia and astroglia before and after the removal of occlusal interferences in rats and to further understand whether astroglia and microglia activation is involved in experimental occlusal interference-induced masticatory muscle pain. Methods: Male Sprague-Dawley rats (200-220 g) were used. Crowns of two heights (0.2 mm and 0.4 mm) were bonded to the right maxillary first molars to establish experimental rat models of occlusal interference. The rats were randomly assigned to one of five groups of twelve rats each: sham-occlusal interference control group, 0.4 mm occlusal interference group, 6-day removal of 0.4 mm occlusal interference group, 0.2 mm occlusal interference group, and 6-day removal of 0.2 mm occlusal interference group. The rats were sacrificed by transcardiac perfusion after deep anesthetization on days 3, 5, 7, and 14. Brain stem sections were obtained and processed for immunofluorescence staining of GFAP and OX-42. Expression levels were semiquantitatively analyzed. Results: ① Based on the markers OX-42 and GFAP, trigeminal-spinal nucleus (Vsp) microglia and astroglia showed no activation in the sham-occlusal interference control group. ② In the 0.4 mm and 0.2 mm occlusal interference groups, Vsp microglia and astroglia showed mild to moderate activation after 3-7 days of occlusal interference. Vsp astroglia remained activated on day 14, but Vsp microglia did not. At the same time point, the 0.4 mm occlusal interference group had greater activation than the 0.2 mm occlusal interference group. ③ In the 6-day removal of 0.4 mm and 0.2 mm occlusal interference groups, microglia and astroglia activation decreased after removal of the occlusal interference. Vsp astroglia remained activated on day 14, but microglia showed no activation. Conclusion Microglia and astrocyte activation is induced in the Vsp after experimental occlusal interference. The astrocytes remained activated for longer than the microglia. The glia activation level is closely related to the intensity of occlusal interference.