[Association between long-term exposure to ambient ozone and sperm quality in Shandong Province].

Objective: To evaluate the association between long-term exposure to ambient ozone (O3) and sperm quality. Methods: From January 1, 2014, to December 31, 2019, healthy sperm donors were recruited through the Human Sperm Bank of Shandong University Affiliated Reproductive Hospital. A total of 37 977 sperm donation data from 2 971 healthy volunteers were analyzed. The average annual O3 concentration (0.01°× 0.01°) was matched according to household address. A multivariate mixed-effect model was used to analyze the exposure-response relationship between the average O3 exposure concentration and sperm quality in the previous year, with each donor as a random intercept. All results were presented as % changes with 95% confidence intervals (CIs) for all sperm parameters associated with 10 µg/m3 increases in O3. The effects of individual characteristics on the association between O3 and sperm quality were evaluated by stratified analysis. Results: The average O3 concentration in the year before semen collection was (107.09±7.50) µg/m3. Each 10 µg/m3 increase in O3 was associated with declined sperm concentration (-3.12%, 95%CI:-4.55%, -1.67%), total sperm count (-5.21%, 95%CI:-7.28%, -3.09%), total sperm motility (-1.49%, 95%CI:-2.37%, -0.61%), progressive motility (-2.53%, 95%CI:-3.78%, -1.26%), total motile sperm count (-5.82%, 95%CI:-8.17%, -3.41%), and progressively motile sperm count (-6.22%, 95%CI:-8.73%, -3.64%). Men aged 30 and above, obese, and with lower education levels might be more susceptible to the influence of O3 on sperm quality, but the difference was not statistically significant (P>0.05). Conclusion: Long-term exposure to O3 in Shandong Province is associated with a decrease in sperm quality.

Structural difference analysis of adult's intestinal flora basing on the 16S rDNA gene sequencing technology.

OBJECTIVE: Through 16S rDNA technology, we aimed at separating adults aging 20-50 years old into a few groups and processing the high-throughput sequencing analysis, in order to explore the features and differences of intestinal flora in each age group in a microcosmic perspective. PATIENTS AND METHODS: 120 stool specimens were collected strictly in accordance with acceptance criteria and exclusion criteria. 49 subjects aging 20-29 years old (Group AGE1), 51 subjects aging 30-39 years old (Group AGE2), and 20 subjects aging 40-49 years old (Group AGE3) were divided into 3 groups. Bacteria DNA from fresh stool specimens of 3 groups were abstracted. Illumina MiSeq high-throughput sequencing platform was applied to process 16S rDNA sequencing in Area 338F_806R for intestinal flora detection. I-Sanger Bio-cloud platform was applied for the analysis of intestinal flora structure changes in phylum level and genus level. RESULTS: Among the age of 20-50, with older age, the abundance of intestinal flora decreased among healthy adults more than 40 years old. In addition, the diversity and sample dispersion of intestinal flora is significantly different from people among 20-40 years old. The decrease ratio of Firmicutes/Bacteroidetes indicated that as the age grows, glucose tolerance might decrease. Comparing with people among 20-40 years old, the amount of Bifidobacterium and Eubacterium in people over 40 years old have significantly decreased. The decrease of Bifidobacterium and Eubacterium may increase the risks of cognitive impairment and lower the anti-inflammation and anti-cancer efficacy in human body, respectively. Subdoligranulum relates to poor metabolism and chronic inflammation and it happens more in people aged over 40 than young people who are among 20-40 years old. CONCLUSIONS: There are differences in the intestinal flora of healthy adults aged 20-50. Effective intervention of the intestinal flora may play a role in delaying aging and preventing diseases.

[Regulation of dentin remineralization progress by non-collagenous protein analogues].

The use of various biomimetic methods to achieve remineralization of demineralized dentin and the formation of an organic matrix-inorganic mineral complex with a certain mechanical strength has been a research hotspot in recent years in the field of stomatology, and it also provides a new idea for the restoration of dentin defect. Dentin biomineralization is a process that simulates the mineralization of biological tissue in nature in which the remineralization of dentin collagen is induced and regulated by organic macromolecules. This review summarizes the process of remineralization of decalcified dentin regulated by non-collagenous protein analogues in vitro.