CBCT Assessment of the Anatomical Characteristics of Gubernacular Canal in Impacted Teeth.

Statement of the Problem: Gubernacular canal (GC) is a canal that extends from the follicle of unerupted permanent teeth to the alveolar bone crest filled with remnants of the dental lamina. This canal is thought to guide tooth eruption and be related to some pathologic conditions. Purposes: This study aimed to determine the presence of GC and its anatomical characteristics in teeth, which failed to erupt normally on cone beam computed tomography (CBCT) images. Materials and Method: This cross-sectional study evaluated CBCT images of 77 impacted permanent and supernumerary teeth obtained from 29 females and 21 males. The frequency of GC detection, its location in relation to the crown and root, the anatomical surface of the tooth from which the canal has originated, and the adjacent cortical table to which the canal opens, along with the length of the GC were studied. Results: GC was observed in 53.2% of teeth. The anatomical tooth aspect of origin was occlusal/ incisal in 41.5% and crown in 82.9% of teeth. Moreover, 51.2% of GCs opened in palatal/lingual cortex and 63.4% of canals were not located along the tooth long axis. Finally, GC was detected in 85.7% of teeth undergoing the crown formation stage. Conclusion: Although GC was introduced as an eruption pathway, this canal is also present in impacted teeth. This means that presence of this canal does not promise the normal eruption of tooth and the anatomical characteristics of GC may influence the eruption process.

Long non-coding RNA NR2F2-AS1: its expanding oncogenic roles in tumor progression.

Long non-coding RNA (LncRNA) is a new type of non-coding RNA whose transcription is more than 200 nucleotides in length and can be up to 100 kb. The crucial regulatory function of lncRNAs in different cellular processes is now notable in many human diseases, especially in different steps of tumorigenesis, making them clinically significant. This research tried to collect all evidence obtained so far regarding Nuclear Receptor subfamily 2 group F member 2 Antisense RNA 1 (NR2F2-AS1) to explore its role in carcinogenesis and molecular mechanism in several cancers. Collecting evidence value an oncogenic role for NR2F2-AS1, whose dysregulation changes the status for cancerous cells to gain the supremacy toward cellular proliferation, dissemination, and ultimately migration. The NR2F2-AS1 acts as competitive endogenous RNA (ceRNA) and contains several microRNA response elements (MREs) for different microRNAs involved in various pathways such as PI3K/AKT, Wnt/ß-catenin, and TGF-ß. This clinically makes NR2F2-AS1 a remarkable lncRNA which contributes to cancer progression and invasion and perhaps could be a candidate as a prognostic marker or even a therapeutic target.

The Inhibitory Effect of Sulforaphane on The Proliferation of Acute Myeloid Leukemia Cell Lines through Controlling miR-181a.

OBJECTIVE: The present study investigated the role of miR-181a as a small non-coding RNA molecule in acute myeloid leukemia (AML) pathogenesis and reflected on the effects of Sulforaphane (SFN) on AML progression. MATERIALS AND METHODS: This experimental study had two parts. In vivo study, the miR-181a levels was measured in patients with symptoms of AML and compared to healthy controls (HCs) to investigate its role in AML pathogenesis. Afterward, an in vitro study was performed to examine the effects of SFN on the growth, apoptosis and proliferation rate of AML cell lines. Finally, the effect of SFN on miR-181a was evaluated as a major miRNA involved in hematopoiesis. RESULTS: The results of this study showed an increasing trend (2.9-fold, P=0.0019) in miR-181a expression levels in AML patients as compared with HCs. The data associated with MTT assay and flow cytometry (FCM) additionally demonstrated the anti-proliferative effects of SFN against AML cell lines, with a reduction in miR-181a levels. As well, no significant difference was noted between 24 hours and 48 hours treatments by SFN. It was deduced that modulation of miR-181a expression levels could be one of the mechanisms associated with the anti-proliferative effects of SFN against AML. CONCLUSION: MiR-181a levels contribute to AML pathogenesis and thus they can be considered as a strategy in controlling AML progression in patients. Accordingly, SFN can arrest cell proliferation and induce apoptosis in AML cell lines through retardation expression of miR-181a and affecting miR-181a pathway, which already clarified its role in the differentiation of hematopoietic stem cells and indicates another mode of anti-cancer action of sulforaphane.

The impact of variations in transcription of DICER and AGO2 on exacerbation of childhood B-cell lineage acute lymphoblastic leukaemia.

The expression of microRNA in eukaryotic cells is subject to tightly regulated processing. The altered expression of microRNAs in a number of cancers suggests their contribution to disease pathogenesis, where processing pathways may be involved in disease pathogenesis. In the present study, we evaluated changes in the profile of two main components of microRNA biogenesis, AGO2 and DICER, and assessed their correlation with disease progression in childhood acute lymphoblastic leukaemia (ALL). To achieve this aim, 25 patients afflicted with ALL were included in the study along with 25 healthy subjects as control. The expression level of AGO2 and DICER was evaluated by real-time PCR. The results revealed an increase in the expression of DICER and a decrease in AGO2 in patients. The correlation between the alteration levels of these genes with pathologic events was also studied. This increase or decrease proved to be directly correlated with the progression of the disease particularly in L1 to L2. According to the obtained results, it can be deduced that dysregulation in transcription of DICER and AGO2, involved in the formation of mature microRNAs in cytoplasm of ALL cancer cells, is a part of the pathological molecular mechanism implicated in the exacerbation of this malignancy. Therefore, the genes involved in microRNAs biogenesis that have been studied here could be considered as candidate prognostic markers especially in childhood ALL which will help towards a better understanding of the molecular basis of ALL.

Restraining the Proliferation of Acute Lymphoblastic Leukemia Cells by Genistein through Up-regulation of B-cell Translocation Gene-3 at Transcription Level.

BACKGROUND: Acute lymphoblastic leukemia (ALL) is a highly prevalent pediatric cancer accounting for approximately 78% of leukemia cases in patients younger than 15 years old. Different studies have demonstrated that B-cell translocation gene 3 (BTG3) plays a suppressive role in the progress of different cancers. Genistein is considered a natural and biocompatible compound and a new anti-cancer agent. In this study, we evaluate the effect of genistein on BTG3 expression and proliferation of ALL cancer cells. MATERIALS AND METHODS: ALL cell lines (MOLT4, MOLT17, and JURKAT) were cultured in standard conditions. Cytotoxicity of genistein was detected using MTT assay. The cells were treated with different concentrations of genistein (10, 25, 40, and 55µM) for 24, 48, and 72 hours, and then cell viability and growth rate were measured. The quantitative real-time polymerase chain reaction was applied to investigate the effect of genistein on BTG3 expression. RESULTS: The percentage of vital cells treated with genistein significantly decreased compared to the non-treated cells, showed an inverse relationship with an increasing genistein concentration. The present study suggests a dose of 40µM for genistein as a potent anticancer effect. Genistein could elevate BTG3 for 1.7 folds in MOLT4 and JURKAT and 2.7 folds in MOLT17 cell lines at transcription level conveged with 60 to 90% reduction in the proliferation rate of cancer cells. CONCLUSION: Up-regulation of BTG3 as a tumor suppressor gene can be induced by genistein. It seems that BTG3 reactivation can be introduced as another mechanism of anti-proliferative effect of genistein and could be considered as a retardant agent candidate against hematopoietic malignancy.

Branching of mandibular canal on cone beam computed tomography images.

BACKGROUND: Mandibular neurovascular canal contents may be vulnerable to damage during mandibular surgical procedures. Greater knowledge of the location and configuration of the mandibular canal can help in the safe performance of these procedures in the dental clinic. Cross-sectional CBCT imaging is a good modality for studying the course, location, configuration and accessory branches of the mandibular canal. The aim of this study was to observe the branching of the mandibular canal at different segments of the mandible and mandibular tooth groups. METHODS: CBCT images of 116 mandibular halves were included in this study. The presence of secondary branching of the mandibular canal in the ramus, retromolar area, molar and premolar teeth as well as the length, diameter and angle of these branches were observed. RESULTS: sixty nine mandibular halves (59.5%), had a main canal with no branching, There were 36 IAC (31%) with one, 8 (6.9%) with two, 2 (1.7%) with three and 1(0.9%) with 5 accessory branches. Of these secondary branches, 16 (25.4%) were in the ramus, 16(25.4%) in the retromolar, and 31(49.2%) in the molar regions. CONCLUSION: Advanced cross-sectional imaging modalities especially CBCT is a suitable tool for observing anatomic characteristics of mandibular canal to preserve this vital structure in surgical procedures.

Effect of lengthy root canal therapy sessions on temporomandibular joint and masticatory muscles.

BACKGROUND AND AIMS: Trauma is one of the major factors associated with temporomandibular joint disorders (TMD). These disorders result from macro-trauma or micro-trauma. Macro-trauma might be iatrogenic; for example, from intuba-tion procedures, third molar extraction procedures, and lengthy dental appointments. The aim of this study was to evaluate the effect of lengthy root canal therapy (more than 2 hours) on TMJ and its supporting structures. MATERIALS AND METHODS: Eighty patients whose root canal therapy session lasted more than 2 hours were examined for the status of TMJ and masticatory muscles. After one week the second part of the examination was carried out for TMJ problems and pain and tenderness levels of masticatory muscles. Data was analyzed using Wilcoxon statistical test. RESULTS: Women showed more pain compared to men. There was a significant increase in pain in the external acoustic meatus examination one week after root canal therapy. Patients who were treated for their posterior teeth suffered more pain than those who were treated for the anteriors and premolars. Other aspects of the examination were not affected significantly by lengthy root canal therapy. CONCLUSION: Lengthy dental treatments can harm TMJ and masticatory muscles and wide opening of the mouth during such appointments can worsen the situation. Therefore, it is wise to break the appointment into shorter intervals and let the patients rest during treatment to close their mouth to prevent iatrogenic damage to TMJ.