Prevalence and characteristics of accessory mandibular canals in an eastern Chinese population by cone beam computed tomography.

PURPOSE: This retrospective study aimed to determine the prevalence and morphological characteristics of accessory mandibular canals (AMCs) in an eastern Chinese population to provide clinical guidance for reducing intraoperative and postoperative complications. METHODS: Cone beam computed tomography (CBCT) scans of 300 Chinese patients were used to identify AMCs according to a modification of Naitoh's classification. The length of the branch (L0) and the upper and lower angles between the branch and mandibular canal were measured on sagittal images. Additionally, the branches were divided into narrow or wide types by calculating the ratio of the branch diameter to the main canal diameter. The location of the bifurcation point was characterized by measuring its distance to the buccal wall of the mandible (L1), lingual wall of the mandible (L2) and alveolar ridge (L3). RESULTS: The prevalence rate of AMCs was 40.7% (95% CI: 35.1-46.3), and the most common type was the retromolar canal, followed by the forward canal, dental canal, trifid mandibular canals (TMCs) or others, inferior canal and buccolingual canal. Twenty-one cases of multiple branches with unusual patterns were observed in the study. The average values of L0, L1, L2 and L3 were 15.05 ± 0.63 mm, 5.79 ± 0.14 mm, 4.40 ± 0.18 mm and 14.61 ± 0.31 mm, respectively. The mean upper angle and lower angle were 141.59° ± 2.44° and 50.64° ± 2.57°, respectively. Approximately 20.8% of the branches were defined as wide type, and no statistical significance was found between different types. CONCLUSION: AMCs are not rare anatomic variations of the mandibular canal in the eastern Chinese population; thus, CBCT examination is highly recommended for precise evaluation before surgeries involving the mandibles.

Microcystin-LR and polystyrene microplastics jointly lead to hepatic histopathological damage and antioxidant dysfunction in male zebrafish.

The co-occurrence of cyanobacterial blooms and nano-microplastic pollution in the water is becoming an emerging risk. To assess the combined hepatotoxicity of microcystin-LR (MC-LR) and polystyrene microplastics (PSMPs) on zebrafish (Danio rerio), male adult zebrafish were exposed to single MC-LR (0, 1, 5, 25 µg/L) and a mixture of MC-LR and PSMPs (100 µg/L). After 60 d exposure, the results indicated that PSMPs significantly increased the MC-LR bioaccumulation in the livers in contrast to the single 25 µg/L MC-LR treatment group. Moreover, the severity of hepatic pathological lesions was aggravated in the MC-LR + PSMPs treatment groups, which were mainly characterized by cellular vacuolar degeneration, swollen hepatocytes, and pyknotic nucleus. The ultrastructural changes also proved that PSMPs combined with MC-LR could enhance the swollen mitochondria and dilated endoplasmic reticulum. The biochemical results, including increased malondialdehyde (MDA) and decreased glutathione (GSH), indicated that PSMPs intensified the MC-LR-induced oxidative damage in the combined treatment groups. Concurrently, alterations of sod1 and keap1a mRNA levels also confirmed that PSMPs together with MC-LR jointly lead to enhanced oxidative injury. Our findings demonstrated that PSMPs enhanced the MC-LR bioavailability by acting as a vector and exacerbating the hepatic injuries and antioxidant dysfunction in zebrafish.

Polystyrene microplastics enhance the microcystin-LR-induced gonadal damage and reproductive endocrine disruption in zebrafish.

The coexistence of eutrophication and plastic pollution in the aquatic environment is becoming a realistic water pollution problem worldwide. To investigate the microcystin-LR (MC-LR) bioavailability and the underlying reproductive interferences in the presence of polystyrene microplastic (PSMPs), zebrafish (Danio rerio) were exposed to individual MC-LR (0, 1, 5, and 25 µg/L) and combined MC-LR + PSMPs (100 µg/L) for 60 d. Our results showed that the existence of PSMPs increased the accumulation of MC-LR in zebrafish gonads compared to the MC-LR-only group. In the MC-LR-only exposure group, seminiferous epithelium deterioration and widened intercellular spaces were observed in the testis, and basal membrane disintegration and zona pellucida invagination were noticed in the ovary. Moreover, the existence of PSMPs exacerbated these injuries. The results of sex hormone levels showed that PSMPs enhanced MC-LR-induced reproductive toxicity, which is tightly related to the abnormal increase of 17ß-estradiol (E2) and testosterone (T) levels. The changes of gnrh2, gnrh3, cyp19a1b, cyp11a, and lhr mRNA levels in the HPG axis further proved that MC-LR combined with PSMPs aggravated reproductive dysfunction. Our results revealed that PSMPs could increase the MC-LR bioaccumulation by serving as a carrier and exaggerate the MC-LR-induced gonadal damage and reproductive endocrine disruption in zebrafish.

Phthalates in plastic bottled non-alcoholic beverages from China and estimated dietary exposure in adults.

Concentrations of six phthalates were determined in 69 plastic bottled non-alcoholic beverages collected from marketplaces in China. Di-n-butyl phthalate (DBP) and di-(2-ethylhexyl)-phthalate (DEHP) were the most detected compounds with frequencies of 100%. Dimethyl phthalate was found less, with a mean frequency of almost 34%. The samples were divided into seven groups. The frequencies of phthalates in these groups ranged from 6.67% to 100%, which indicated that different types of beverages were differently contaminated by phthalates. DEHP contained the highest mean and median concentrations (1.60 ng g-1 and 0.62 ng g-1), followed by DBP (1.34 ng g-1 and 0.27 ng g-1). For DBP, the highest phthalate concentration of 14.3 ng g-1 was measured. The results of estimated daily intake (EDI) showed that the risk of Chinese adults exposed to these 6 phthalates in beverages examined was lower than the reference doses as suggested by the United States Environmental Protection Agency. The range of EDI values was between 1.77 × 10-4 µg kg-bw-1 day-1 and 0.478 µg kg-bw-1 day-1.