Intrauterine exposure to 2,3',4,4',5-pentachlorobiphenyl alters spermatogenesis and testicular DNA methylation levels in F1 male mice.

Polychlorinated biphenyls (PCBs) are synthetic biphenyl compounds with high toxicity. There are a total of 209 homologs, among which 2,3',4,4',5-pentachlorobiphenyl (PCB118) is one of the dioxin-like PCBs. PCB118 can accumulate in pregnant mice, leading to fetus directly exposure during development. The stage of migration of mouse primordial germ cells ranges from 8.5 to 13.5 days of pregnancy, which is the stage undergoing a genome-wide DNA demethylation process. In this study, the mice were exposed to 20 µg/kg/day and 100 µg/kg/day PCB118 from 8.5 to 13.5 days of pregnancy. During the embryo stage at 18.5 days (E18.5 days), the expression level of DNA methyltransferase 1 (Dnmt1) was reduced in the testes, and the DNA methylation level in mouse testes were also decreased. We found that the seminiferous tubules showed vacuolization and that the sperm deformity rate increased in the treated groups compared with the control group in 7-week-old mice. Because exposure to PCB118 during pregnancy causes damage to the reproductive system of male offspring mice, attention should be devoted to the toxicity transmission of persistent environmental pollutants such as PCBs.

[The effect of calcium hydroxide on IL-6 and TNF-α expression of osteoblast in periapical tissues].

PURPOSE: To compare the effect of calcium hydroxide in different position on pH and inflammation factor expression of periapical osteoblasts. METHODS: 140 sterilized single-rooted human teeth models were randomly divided into 6 experiment groups and one control group: Group 1-3:calcium hydroxide paste was placed in the apical half of root canal, the upper half of root canal and the pulp champer; Group 4-6:Apexcal was placed in the apical half of root canal, the upper half of root canal and the pulp champer; Group 7: the control group without medication. 10 teeth of each group were placed in P.e suspension, the IL-6 and TNF-α expression of MC3T3-E1 was tested at 3 d and 7 d. The other teeth of each group were placed in distilled water, and the pH in periapical region was tested at 3, 7, 14 and 21 d. SPSS 13.0 software package was used for statistical analysis. RESULTS: Calcium hydroxide placed in different position of the root canal increased periapical pH value and reached its peak at 14 d. The group in which calcium hydroxide paste was placed in pulp chamber gained lower pH level than other experimental groups. IL-6, TNF-α expression of MC3T3-E1 pretreated by P.e suspension of experimental groups was significantly reduced compared with control group, and there was no significant difference between the experimental groups. CONCLUSIONS: Calcium hydroxide placed in different position of the root canal could increase periapical pH value and reduce IL- 6, TNF-α expression of periapical osteoblasts.

Tumours of the salivary glands in northeastern China: a retrospective study of 2508 patients.

Little information has been published in English about the epidemiology of tumours of the salivary glands in northeastern China. From August 2004 to March 2014, 2508 cases of primary epithelial salivary gland tumours were diagnosed in the Department of Oral and Maxillofacial Surgery, the Affiliated Stomatology Hospital of China Medical University. Tumours were analysed according to their histological type and site, and the age and sex of the patients. Ages ranged from 5 to 98 years, with a slight propensity in favour of men. The peak incidence was in the sixth decade for both sexes. The mean (SD) ages were 48 (16) years when the tumour was benign and 51 (15) years when it was malignant. The parotid gland and palate were the sites most commonly affected. There were 1934 (77.1%) benign and 574 (22.9%) malignant tumours, with the most common histological types being pleomorphic adenomas and mucoepidermoid carcinomas. A lesion that arises from the floor of the mouth (92.8%) or the tongue (86.2%) is more likely to be malignant than those from other minor salivary glands.

Frequency and distribution pattern of minor salivary gland tumors in a northeastern Chinese population: a retrospective study of 485 patients.

PURPOSE: The relative frequency of individual minor salivary gland tumors (MSGTs) is not well documented in the literature. The aim of this study was to determine the range and demographics of all histologically diagnosed MSGTs in a northeastern Chinese population. MATERIALS AND METHODS: A total of 485 cases of MSGT were retrospectively studied. The files of the Department of Oral and Maxillofacial Pathology, School of Stomatology, China Medical University served as a source of material for this study. All epithelial tumors from minor salivary glands accessioned from August 2004 to April 2014 were analyzed for demographic features, anatomic location of tumors, and pathologic classification. Tumors were classified according to the 2005 World Health Organization classification of salivary gland tumors. Statistical analysis was performed using analysis of variance. RESULTS: MSGTs were identified in 485 (2.60%) of 18,670 accessed cases. There were 268 (55.26%) benign and 217 (44.74%) malignant tumors. Female outnumbered male patients (male-to-female ratio, 1:1.43). The mean ages of patients with benign and malignant MSGTs were 47.58 and 51.51 years, respectively. Pleomorphic adenoma and adenoid cystic carcinoma were the most frequent types of benign and malignant tumors, respectively. The palate was the most commonly affected site (64.74%), followed by the buccal mucosa (7.63%) and the tongue (5.98%). CONCLUSIONS: From the results of this study and a review of the literature, it is suggested that MSGTs in the northeastern Chinese population may be characterized by a higher incidence of MSGTs than in the populations of other reviewed regions, a higher incidence of myoepithelioma, a rarer occurrence of polymorphous low-grade adenocarcinoma, and an absence of canalicular adenoma occurrence.