Determining the position of the lingula and the mandibular foramen using the antilingula in orthognathic surgery.

BACKGROUND: The antilingula located on the lateral surface of the mandibular ramus has been served as a surgical landmark for the mandibular foramen on the medial surface for decades. However, whether the antilingula truly represents the lingula which is the bony prominence overlapping the mandibular foramen, or the foramen itself, is still unclear. This study thus aimed to examine the position of the antilingula in relation to three reference points: the lingula, the anterior and the posterior borders of the mandibular foramen, as well as to the reference plane used in the inferior alveolar nerve block, and to the posterior border of the mandible. METHODS: This observational study was performed in 113 Thai dry mandibles. The antilingula were identified followed by transferring the reference points to the lateral surface. The distances from the antilingula to the reference points, the reference plane and the posterior border of the ramus were then measured. Chi-square test was calculated for side-dependency of the antilingula. Paired t-test was calculated for difference in measurements in left and right sides. RESULTS: The antilingula could be identified in 92.48% of the mandibles with 86.67 - 90.00% accuracy and 86.67% reliability. There was no significant difference in the presence of the antilingula on left and right sides (p = 0.801). Only 2.5% and 0.83% of the antilingula correspond to the lingula and the anterior border of the mandibular foramen, respectively. However, 85% of the reference points were located within 11 mm radius. The antilingula was found located 2.80 mm inferior to the reference plane and 16.84 mm from the posterior border of the ramus. CONCLUSIONS: The antilingula does not concur with the reference points on the medial surface. Our study also suggests that the safe area for vertical osteotomy is 11 mm posterior to the antilingula or at 30% of the length from the posterior border parallel to the occlusal plane. The use of more accurate techniques in localizing the mandibular foramen combined with the antilingula is more recommended than using the antilingula as a sole surgical guide.

Proteomic profiling reveals neuronal ion channel dysregulation and cellular responses to DNA damage-induced cell cycle arrest and senescence in human neuroblastoma SH-SY5Y cells exposed to cypermethrin.

Cypermethrin (CYP), a synthetic pyrethroid of class II, is widely used as a pesticide worldwide. The primary target of cypermethrin is a voltage-gated sodium channel. The neurotoxicity of CYP has been extensively studied in terms of affecting neuronal development, increasing cellular oxidative stress, and apoptosis. However, little is known about how it affects the expression of channel proteins involved in synaptic transmission, as well as the effects of cypermethrin on DNA damage and cell cycle processes. We found that the ligand and voltage-gated calcium channels and proteins involved in synaptic transmission including NMDA 1 receptor subunit, alpha 1A-voltage-dependent calcium channel, synaptotagmin-17, and synaptojanin-2 were downregulated in CYP-treated cells. After 48 h of CYP exposure, cell viability was reduced with flattened and enlarged morphology. The levels of 23 proteins regulating cell cycle processes were altered in CYP-treated cells, according to a proteomic study. The cell cycle analysis showed elevated G0/G1 cell cycle arrest and DNA fragmentation at the sub-G0 stage after CYP exposure. CYP treatment also increased senescence-associated ß-galactosidase positive cells, DNA damage, and apoptotic markers. Taken together, the current study showed that cypermethrin exposure caused DNA damage and hastened cellular senescence and apoptosis via disrupting cell cycle regulation. In addition, despite its primary target sodium channel, CYP might cause synaptic dysfunction via the downregulation of synaptic proteins and dysregulation of synapse-associated ion channels.

Anatomical Variations of the Anterior Belly of the Digastric Muscle in Thai Cadavers: A Cross-Sectional Study.

Aim: Because the digastric muscle is considered as an anatomical landmark, its variations may emphasize clinicians to be cautious during surgery. However, previous studies from different ethnicities reported a wide range of occurrence and several types of this muscle variation, pointing the necessity of the data from local population to better treatment decisions. Thus, this study aimed to explore the variations of the anterior belly of the digastric muscle in Thai cadavers. Materials and Methods: This cross-sectional study investigated the submental region of 91 cadavers by convenient sampling method. The characteristics of the variation in the anterior belly were recorded in accordance with sex and side of the cadavers. Multiple logistic regression was calculated for determining the association of occurrence of muscle variation with sexes and sides (α = 0.05). Results: Among 91 cadavers, the accessory bundles were observed in 16 cadavers (10 males and 6 females). The presence of the additional belly was sex and side independent. Three variation types were observed; the arrowhead type and the double-headed type have been previously reported, whereas the asymmetrical fan-shaped type is the new variant that has never been described before. Conclusions: The variation of the anterior belly of the digastric muscle including the new variant can be seen in Thais with low occurrence. To our knowledge, the present study is the first report of the aberrations of the digastric muscle in the Southeast Asian population. Therefore, our study provides the basis for anatomical study of muscular variants and helps surgeons plan the operation to prevent iatrogenic injuries.

Ebselen as template for stabilization of A4V mutant dimer for motor neuron disease therapy.

Mutations to the gene encoding superoxide dismutase-1 (SOD1) were the first genetic elements discovered that cause motor neuron disease (MND). These mutations result in compromised SOD1 dimer stability, with one of the severest and most common mutations Ala4Val (A4V) displaying a propensity to monomerise and aggregate leading to neuronal death. We show that the clinically used ebselen and related analogues promote thermal stability of A4V SOD1 when binding to Cys111 only. We have developed a A4V SOD1 differential scanning fluorescence-based assay on a C6S mutation background that is effective in assessing suitability of compounds. Crystallographic data show that the selenium atom of these compounds binds covalently to A4V SOD1 at Cys111 at the dimer interface, resulting in stabilisation. This together with chemical amenability for hit expansion of ebselen and its on-target SOD1 pharmacological chaperone activity holds remarkable promise for structure-based therapeutics for MND using ebselen as a template.

The anti-inflammatory effect of melatonin in SH-SY5Y neuroblastoma cells exposed to sublethal dose of hydrogen peroxide.

Brain inflammaging is considered as one of the underlying factors of neurodegenerative diseases. The present study aimed to investigate the effects of melatonin, an endogenous indoleamine mainly synthesized by the pineal gland, on hydrogen peroxide (H2O2)-induced inflammaging state in SH-SY5Y cells. Our data showed that p21Cip1 and p16INK4a, cell cycle arrest markers, and the number of senescence-associated ß-galactosidase (SA-ßgal) staining increased significantly in H2O2-treated cells. Melatonin treatment could reverse this effect. Flow cytometry analysis showed a significantly higher percentage in the G0/G1 phase and a lower proportion in the S phase of H2O2 treated cells. Cells pretreated with H2O2 showed a dramatic decrease in the formation of Ki67 immunoactivity while the treatment with melatonin increased Ki67-positive cell. Both mRNA and protein expression levels of the pro-inflammatory cytokines, interleukin-1ß (IL-1ß), IL-6 and, tumor necrosis factor-α (TNF-α) which were increased after induction with H2O2, could be attenuated by melatonin. In addition, melatonin decreased the phospho-nuclear factor kappa B (pNF-κB) expression and prevented its nuclear translocation, as well as abrogated the reduction of nuclear factor erythroid 2-related factor 2 (Nrf2) in SH-SY5Y cells exposed to H2O2. The present data suggested the importance of melatonin on ameliorating inflammation in SH-SY5Y cells.