Morphology of the temporalis muscle focusing on the tendinous attachment onto the coronoid process / 대한해부학회지

The temporalis muscle is usually described as a single layer originating at the temporal line, converging to a tendon, and inserting onto a narrow site of the coronoid process. However, recent studies have shown that the temporalis muscle can be divided into two or three separate segments and the distal attachment continues inferiorly beyond the coronoid process. Therefore, the aims of this study were to analyze the morphology of the temporalis muscle focusing on the tendinous attachment onto the coronoid process and to provide educational values. The temporalis muscle was carefully dissected in 26 cadavers and classified based on the muscle fascicle direction. Each divided part was sketched and measured based on bony landmarks to elucidate its tendinous insertion site onto the coronoid process, and the results obtained were reviewed through the literature. The temporalis muscle ends at two distinct terminal tendons with wider insertion sites than usually presented in textbooks and atlases and separates into two parts that combine to act as a single structural unit. The superficial part is a large fan-shaped muscle commonly recognized as the temporalis muscle. This converges infero-medially to form the superficial tendon and the lateral boundary of the retromolar triangle. Meanwhile, the deep part is a narrow vertically oriented rectangular muscle that converges postero-laterally to form the deep tendon and the medial boundary of the retromolar triangle. These results indicate that understanding the temporalis muscle’s insertion site onto the coronoid process will be useful clinically with educational values during surgical procedures.

Alpha-lipoic acid protects human dopaminergic neuronal cells against hydrogen peroxide-induced cell injury by inhibiting autophagy and apoptosis

Alpha-lipoic acid (ALA) is a naturally occurring antioxidant and has been previously used to treat diabetes and cardiovascular disease. However, the autophagy effects of ALA against oxidative stress-induced dopaminergic neuronal cell injury remain unclear. The aim of this study was to investigate the role of ALA in autophagy and apoptosis against oxidative stress in the SH-SY5Y human dopaminergic neuronal cell line. We examined SH-SY5Y phenotypes using the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assay (cell viability/proliferation), 4′,6-diamidino-2-phenylindole dihydrochloride nuclear staining, Live/Dead cell assay, cellular reactive oxygen species (ROS) assay, immunoblotting, and immunocytochemistry. Our data showed ALA attenuated hydrogen peroxide (H2O2)-induced ROS generation and cell death. ALA effectively suppressed Bax up-regulation and Bcl-2 and BclxL down-regulation. Furthermore, ALA increased the expression of the antioxidant enzyme, heme oxygenase-1. Moreover, the expression of Beclin-1 and LC-3 autophagy biomarkers was decreased by ALA in our cell model. Combined, these data suggest ALA protects human dopaminergic neuronal cells against H2O2-induced cell injury by inhibiting autophagy and apoptosis.

Morphology of the temporalis muscle focusing on the tendinous attachment onto the coronoid process / 대한해부학회지

The temporalis muscle is usually described as a single layer originating at the temporal line, converging to a tendon, and inserting onto a narrow site of the coronoid process. However, recent studies have shown that the temporalis muscle can be divided into two or three separate segments and the distal attachment continues inferiorly beyond the coronoid process. Therefore, the aims of this study were to analyze the morphology of the temporalis muscle focusing on the tendinous attachment onto the coronoid process and to provide educational values. The temporalis muscle was carefully dissected in 26 cadavers and classified based on the muscle fascicle direction. Each divided part was sketched and measured based on bony landmarks to elucidate its tendinous insertion site onto the coronoid process, and the results obtained were reviewed through the literature. The temporalis muscle ends at two distinct terminal tendons with wider insertion sites than usually presented in textbooks and atlases and separates into two parts that combine to act as a single structural unit. The superficial part is a large fan-shaped muscle commonly recognized as the temporalis muscle. This converges infero-medially to form the superficial tendon and the lateral boundary of the retromolar triangle. Meanwhile, the deep part is a narrow vertically oriented rectangular muscle that converges postero-laterally to form the deep tendon and the medial boundary of the retromolar triangle. These results indicate that understanding the temporalis muscle’s insertion site onto the coronoid process will be useful clinically with educational values during surgical procedures.

Alpha-lipoic acid protects human dopaminergic neuronal cells against hydrogen peroxide-induced cell injury by inhibiting autophagy and apoptosis

Alpha-lipoic acid (ALA) is a naturally occurring antioxidant and has been previously used to treat diabetes and cardiovascular disease. However, the autophagy effects of ALA against oxidative stress-induced dopaminergic neuronal cell injury remain unclear. The aim of this study was to investigate the role of ALA in autophagy and apoptosis against oxidative stress in the SH-SY5Y human dopaminergic neuronal cell line. We examined SH-SY5Y phenotypes using the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assay (cell viability/proliferation), 4′,6-diamidino-2-phenylindole dihydrochloride nuclear staining, Live/Dead cell assay, cellular reactive oxygen species (ROS) assay, immunoblotting, and immunocytochemistry. Our data showed ALA attenuated hydrogen peroxide (H2O2)-induced ROS generation and cell death. ALA effectively suppressed Bax up-regulation and Bcl-2 and BclxL down-regulation. Furthermore, ALA increased the expression of the antioxidant enzyme, heme oxygenase-1. Moreover, the expression of Beclin-1 and LC-3 autophagy biomarkers was decreased by ALA in our cell model. Combined, these data suggest ALA protects human dopaminergic neuronal cells against H2O2-induced cell injury by inhibiting autophagy and apoptosis.