Smoking by altering the peri-implant microbial community structure compromises the responsiveness to treatment.

Smoking is an essential risk factor for peri-implant diseases. It also hampers the clinical outcomes of peri-implant therapies. Nonetheless, the effect of smoking can go undetected until the emergence of clinical signs. Bacterial-induced inflammation is responsible for the initiation and progression of peri-implant diseases. We hypothesize that smoking impacts the peri-implant microbiome even in status of clinical health, putting it into a sub-healthy condition that responds poorly to peri-implant treatments. To validate this, peri-implant plaque samples from 18 participants including 10 smokers (S) and 8 non-smokers (NS), who had received implant prostheses were analyzed using metagenomic shotgun sequencing. The results showed that in addition to taxonomical and functional differences, the local stability in the S group was also shown to be much higher than that in the NS group, indicating greater stubbornness of the peri-implant microbiome associated with smoking. Besides, the topological structures were also distinct between the two groups. The highly connected species interacted more preferentially with each other in the S group (eigenvector centralization, 0.0273 in S and 0.0183 in NS), resulting in a greater tendency of forming small-world modules (modularity, 0.714 in S and 0.582 in NS). While in the NS group, inter-species correlations were more evenly distributed (clustering coefficient, 0.532 in S and 0.666 in NS). These alterations overall explained the greater stubbornness of the peri-implant microbiome associated with smoking, which may cause poor responsiveness to peri-implant therapies. From a microbial perspective, this may be a potential reason why smoking impacts negatively on the outcome of peri-implant treatments.

Periodontal and Peri-Implant Microbiome Dysbiosis Is Associated With Alterations in the Microbial Community Structure and Local Stability.

Periodontitis and peri-implantitis are common biofilm-mediated infectious diseases affecting teeth and dental implants and have been considered to be initiated with microbial dysbiosis. To further understand the essence of oral microbiome dysbiosis in terms of bacterial interactions, community structure, and microbial stability, we analyzed 64 plaque samples from 34 participants with teeth or implants under different health conditions using metagenomic sequencing. After taxonomical annotation, we computed the inter-species correlations, analyzed the bacterial community structure, and calculated the microbial stability in supra- and subgingival plaques from hosts with different health conditions. The results showed that when inflammation arose, the subgingival communities became less connective and competitive with fewer hub species. In contrast, the supragingival communities tended to be more connective and competitive with an increased number of hub species. Besides, periodontitis and peri-implantitis were associated with significantly increased microbial stability in subgingival microbiome. These findings indicated that the periodontal and peri-implant dysbiosis is associated with aberrant alterations in the bacterial correlations, community structures, and local stability. The highly connected hub species, as well as the major contributing species of negative correlations, should also be given more concern in future studies.

Chemical antagonism between photodynamic agents and chemotherapeutics: mechanism and avoidance.

We report a photochemical reaction-induced antagonism between the photodynamic agent (PS) and anti-cancer drugs during combined therapy. The annihilation of singlet oxygen and alkene-containing drugs into inactive drug hydroperoxides is responsible for the antagonism, and results in decreased efficacy against several cancer cell lines. Experimental and simulation results reveal that the annihilation abates with increasing distance between the PS and drugs via confining the PS and drugs into separated vehicles. As a result, antagonism can be switched to synergism in treating both drug sensitive and resistant cancer cells.

[Effects of plastic film mulching on soil CO2 efflux and CO2 concentration in an oasis cotton field].

A field study was conducted to compare soil CO2 efflux and CO2 concentration between mulched and non-mulched cotton fields by using closed chamber method and diffusion chamber technique. Soil CO2 efflux and CO2 concentration exhibited a similar seasonal pattern, decreasing from July to October. Mulched field had a lower soil CO2 efflux but a higher CO2 concentration, compared to those of non-mulched fields. Over the measurement period, cumulative CO2 efflux was 1871.95 kg C . hm-2 for mulched field and 2032.81 kg C . hm-2 for non-mulched field. Soil CO2 concentration was higher in mulched field (ranging from 5137 to 25945 µL . L-1) than in non- mulched field (ranging from 2165 to 23986 µL . L-1). The correlation coefficients between soil CO2 concentrations at different depths and soil CO2 effluxes were 0.60 to 0.73 and 0.57 to 0.75 for the mulched and non-mulched fields, indicating that soil CO2 concentration played a crucial role in soil CO2 emission. The Q10 values were 2.77 and 2.48 for the mulched and non-mulched fields, respectively, suggesting that CO2 efflux in mulched field was more sensitive to the temperature.

[Surgical treatment of carotid stenosis].

OBJECTIVE: To summarize clinical experience of carotid endarterectomy (CEA) in treating severe carotid stenosis. METHODS: Between October 1998 and January 2010, 215 patients with carotid stenosis were treated with CEA. There were 140 males and 75 females with an average age of 66 years (range, 51-88 years). Transient ischemic attack (TIA) occurred in 127 cases, and 31 cases had history of cerebral infarction. All cases were diagnosed definitely by selective angiography and/or CT angiography, and stenosis degree was more than 80%; contralateral carotid artery was also involved in 45 cases. Ninety-six cases were found to have coronary artery stenosis by coronary angiography. CEA and coronary artery bypass grafting were performed simultaneously in 25 cases. Peripheral arterial disease was found in 43 cases and treated at the same time. RESULTS: A total of 155 patients were followed up 6-72 months. The clinical symptom significantly alleviated in 148 cases postoperatively. Two cases had complication of cerebral hemorrhage within 1 week postoperatively; one died and the other was resumed after the conservative treatment. One case had hypoglossal nerve injury. Four cases had injuring marginal mandibular branch of the facial nerve, and no special treatment was given. Restenosis was found in 25 patients, and the stenosis degree was less than 25%; moreover, the patients had no TIA. One case died of heart attack at 3 years of follow-up period. CONCLUSION: CEA is an effective and safe method for treating severe carotid stenosis.