A Knock-In Mouse Model of the Gcm2 Variant p.Y392S Develops Normal Parathyroid Glands.

Context: The glial cells missing 2 (GCM2) gene functions as a transcription factor that is essential for parathyroid gland development, and variants in this gene have been associated with 2 parathyroid diseases: isolated hypoparathyroidism in patients with homozygous germline inactivating variants and primary hyperparathyroidism in patients with heterozygous germline activating variants. A recurrent germline activating missense variant of GCM2, p.Y394S, has been reported in patients with familial primary hyperparathyroidism. Objective: To determine whether the GCM2 p.Y394S missense variant causes overactive and enlarged parathyroid glands in a mouse model. Methods: CRISPR/Cas9 gene editing technology was used to generate a mouse model with the germline heterozygous Gcm2 variant p.Y392S that corresponds to the human GCM2 p.Y394S variant. Wild-type (Gcm2+/+) and germline heterozygous (Gcm2+/Y392S) mice were evaluated for serum biochemistry and parathyroid gland morphology. Results: Gcm2 +/Y392S mice did not show any change compared to Gcm2+/+ mice in serum calcium and parathyroid hormone levels, parathyroid gland histology, cell proliferation, or parathyroid gland size. Conclusion: The mouse model of the p.Y392S variant of Gcm2 shows that this variant is tolerated in mice, as it does not increase parathyroid gland cell proliferation and circulating calcium or PTH levels. Further investigation of Gcm2+/Y392S mice to study the effect of this variant of Gcm2 on early events in parathyroid gland development will be of interest.

Metastatic Grade 3 Neuroendocrine Tumor in Multiple Endocrine Neoplasia Type 1 Expressing Somatostatin Receptors.

Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) may occur in 30% to 90% of patients with multiple endocrine neoplasia type 1 (MEN1). However, only 1% of GEP-NETs are grade 3 (G3). Given the rarity of these aggressive tumors, treatment of advanced G3 GEP-NETs in MEN1 is based on the treatment guidelines for sporadic GEP-NETs. We report a 43-year-old male with germline MEN1 followed at our institution, with clinical features including hyperparathyroidism, a nonfunctional pancreatic NET, and Zollinger-Ellison syndrome. On routine surveillance imaging at age 40, computed tomography/positron emission tomography imaging showed 2 arterially enhancing intraluminal masses on the medial aspect of the gastric wall. Anatomical imaging confirmed 2 enhancing masses within the pancreas and a rounded mass-like thickening along the lesser curvature of the stomach. The gastric mass was resected, and pathology reported a well-differentiated G3 NET with a Ki-67 >20%. The patient continued active surveillance. Eighteen months later cross-sectional imaging studies showed findings consistent with metastatic disease within the right hepatic lobe and bland embolization was done. On follow-up scans, including 68Ga-DOTATATE (68Ga-DOTA(0)-Tyr(3)-octreotate) imaging, interval increase in number and avidity of metastatic lesions were compatible with disease progression. Given a paucity of treatment recommendations for G3 tumors in MEN1, the patient was counseled based on standard NET treatment guidelines and recommended 177Lu-DOTATATE treatment. PRRT (peptide receptor radionuclide therapy) with 177Lu-DOTATATE (177Lu-tetraazacyclododecanetetraacetic acid-octreotide) is an important therapeutic modality for patients with somatostatin receptor-positive NETs. However, prospective studies are needed to understand the role of PRRT in G3 NETs.

Mice With RIP-Cre-mediated Deletion of the Long Noncoding RNA Meg3 Show Normal Pancreatic Islets and Enlarged Pituitary.

Context: Maternally expressed gene 3 (MEG3) is a long noncoding RNA (lncRNA) that has been implicated as a tumor suppressor. Objective: The expression of MEG3 RNA is downregulated in various human tumors, including pituitary adenoma and pancreatic islet tumors due to MEG3 gene deletion or DNA hypermethylation. Mouse models with conventional germline deletion of Meg3 have shown that Meg3 is essential for perinatal or postnatal development and survival. However, a direct role of Meg3 loss in tumorigenesis has not been shown. Methods: To observe a causal relationship between Meg3 loss and tumorigenesis, we have generated a mouse model with conditional deletion of Meg3 mediated by the RIP-Cre transgene that initiated Meg3 deletion in pancreatic islet ß cells and anterior pituitary. Results: Meg3 loss did not lead to the development of islet tumors. Interestingly, RIP-Cre-mediated Meg3 loss led to the development of an enlarged pituitary. The genes in the Meg3 region are transcribed together as a 210 kb RNA that is processed into Meg3 and other transcripts. Whether these tandem transcripts play a functional role in the growth of pancreatic endocrine cells and pituitary cells remains to be determined. Conclusion: Our mouse model shows that Meg3 loss leads to hyperplasia in the pituitary and not in pancreatic islets, thus serving as a valuable model to study pathways associated with pituitary cell proliferation and function. Future mouse models with specific inactivation of Meg3 alone or other transcripts in the Meg3 polycistron are warranted to study tissue-specific effects on initiating neoplasia and tumor development.

Two distinct classes of thymic tumors in patients with MEN1 show LOH at the MEN1 locus.

Patients with the multiple endocrine neoplasia type 1 (MEN1) syndrome carry germline heterozygous loss-of-function mutations in the MEN1 gene which predisposes them to develop various endocrine and non-endocrine tumors. Over 90% of the tumors show loss of heterozygosity (LOH) at chromosome 11q13, the MEN1 locus, due to somatic loss of the wild-type MEN1 allele. Thymic neuroendocrine tumors (NETs) or thymic carcinoids are uncommon in MEN1 patients but are a major cause of mortality. LOH at the MEN1 locus has not been demonstrated in thymic tumors. The goal of this study was to investigate the molecular aspects of MEN1-associated thymic tumors including LOH at the MEN1 locus and RNA-sequencing (RNA-Seq) to identify genes associated with tumor development and potential targeted therapy. A retrospective chart review of 294 patients with MEN1 germline mutations identified 14 patients (4.8%) with thymic tumors (12 thymic NETs and 2 thymomas). LOH at the MEN1 locus was identified in 10 tumors including the 2 thymomas, demonstrating that somatic LOH at the MEN1 locus is also the mechanism for thymic tumor development. Unsupervised principal component analysis and hierarchical clustering of RNA-Seq data showed that thymic NETs formed a homogenous transcriptomic group separate from thymoma and normal thymus. KSR2 (kinase suppressor of Ras 2), that promotes Ras-mediated signaling, was abundantly expressed in thymic NETs, a potential therapeutic target. The molecular insights gained from our study about thymic tumors combined with similar data from other MEN1-associated tumors may lead to better surveillance and treatment of these rare tumors.

Forensic Identification of Endodontically Treated Teeth after Heat-Induced Alterations: An In Vitro Study.

OBJECTIVE: The study aimed to highlight the relationship between forensic science and endodontics by illustrating CBCT records can be used as legal evidence for forensic analysis and evaluate the effect of elevated temperature on the endodontically treated teeth. METHODS: The present study was conducted on 40 extracted permanent mandibular premolars, which were divided into two groups based on predetermined incineration temperature: Group I - 400°C & Group II - 800°C subjected for 15 minutes holding time in a digital burnout furnace. The root canal treatment was performed for both the groups and a Pre-incineration CBCT scan was taken for both the groups as an ante-mortem data. Following heating analysis, root canal treated teeth were examined using a stereomicroscope at 20x resolution to evaluate the morphological changes. The post-incineration CBCT scan was taken as the post-mortem record for each group. Both ante-mortem records and post-mortem records were compared for the forensic analysis. RESULTS: The endodontically treated teeth display a series of macroscopic and stereo-microscopic changes for each temperature scale. The CBCT records identify the thermal stress-induced 3D alterations in the gutta-percha filled teeth. CONCLUSION: Knowledge of changes in human dentition and traces of the endodontically treated teeth can help forensic experts for the identification of the fire victims.

Comparative Evaluation of the Remineralizing Potential of Commercially Available Agents on Artificially Demineralized Human Enamel: An In vitro Study.

BACKGROUND: Caries is highly prevalent multifactorial disease, but its progression can be prevented in the initial stage of demineralization through remineralization (RML). Various materials have been proposed for the same, successful outcome can prove to be a boon in the prevention of caries. AIM: The aim of the study is to assess the RML potential of four commercially available agents so as to restore the enamel closest to its previous microhardness levels. MATERIALS AND METHODS: Sixty permanent intact premolars were randomly divided into six groups: Four test groups - (1) bioactive glass (BAG) Novamin (SHY-NM), (2) nano-hydroxyapatite (nHAp) (Acclaim), (3) functionalized tricalcium phosphate (f-TCP) (Clinpro Tooth Crème), and (4) grape seed extract (GSE); one positive control - (5) fluoride (1000 ppm) containing dentifrice (Colgate Calci-Lock); and one negative control - (6) distilled water. The samples were initially evaluated for baseline surface microhardness (SMH); later on, these samples were placed in the demineralizing solution for 48 h in an incubator at 37°C, and postdemineralization again SMH was measured. Thereafter, the samples were subjected to the pH cycling for consecutive 21 days, and SMH was recorded. The SMH was evaluated using a Vickers microhardness tester. Statistical analysis was done using a post hoc Tukey test for each group based on the stage of treatment and one-way ANOVA for comparison among different groups. RESULTS: BAG Novamin showed SMH recovery at 96.75% followed by f-TCP at 95.83%, nHAp at 90.88%, and GSE at 48.71%. Statistically significant differences were observed between the first three groups and the rest of the groups after RML stage. CONCLUSION: BAG Novamin, f-TCP, and nHAp showed considerable RML followed to a lesser extent by GSE.

Functional Defects From Endocrine Disease-Associated Mutations in HLXB9 and Its Interacting Partner, NONO.

The insulin-secreting pancreatic neuroendocrine tumors, insulinomas, characterized by increased pancreatic islet ß-cell proliferation, express the phosphorylated isoform of the ß-cell differentiation factor HLXB9 that interacts with NONO/p54NRB, a survival factor. Interestingly, two different homozygous germline mutations in HLXB9, p.F248L and p.F272L, were reported in neonatal diabetes, a condition with functional ß-cell deficiency. Also, two somatic heterozygous NONO mutations were found in endocrine-related tumors, p.H146R (parathyroid) and p.R293H (small intestine neuroendocrine tumor). However, the biological consequence of the mutations, and the role of HLXB9-NONO interaction in normal or abnormal ß cells, is not known. Expression, localization, and functional analysis of the clinically relevant HLXB9 and NONO mutants showed that HLXB9/p.F248L mutant localized in the nucleus but lacked phosphorylation, and NONO/p.R293H mutant was structurally impaired. The HLXB9 and NONO mutants retained the ability to interact, and overexpression of wild-type or mutant HXLB9 in MIN6 cells suppressed cell proliferation. To further understand the biological consequence of the HLXB9-NONO interaction, we mapped the NONO-interacting region in HLXB9. An 80-amino acid conserved region of HLXB9 could compete with full-length HLXB9 to interact with NONO; however, in functional assays, nuclear expression of this HLXB9-conserved region in MIN6 cells did not interfere with cell proliferation. Overall, our results highlight the importance of HLXB9 in conditions of ß-cell excess (insulinomas) and in conditions of ß-cell loss or dysfunction (diabetes). Our studies implicate therapeutic strategies for either reducing ß-cell proliferation in insulinomas or alleviating normal ß-cell deficiency in diabetes through the modulation of HLXB9 phosphorylation.

Can active signals of cellphone interfere with electronic working length determination of a root canal in a dental clinic? An in vivo study.

OBJECTIVE: To evaluate the interference of active cellphones during electronic working length (EWL) determination of a root canal. MATERIALS AND METHODS: Thirty patients requiring root canal treatment in the anterior teeth or premolars having single canal and mature apices were selected for this study. Working length determination was done using no. 15 K-file. Electronic apex locators ProPex Pixi and Root ZX mini were used for working length determination. Cellphones iPhone 6s and Xolo Q3000 were evaluated for their interference. The experiment was conducted in a closed room (9 feet × 9 feet). Working length was measured with no cellphone in the room, iPhone 6s in a calling mode, Xolo Q3000 in a calling mode, and Xolo Q3000 and iPhone 6s simultaneously in a calling mode. Stability of the readings was also determined for every condition. STATISTICAL ANALYSIS: The data were statistically analyzed using one-way ANOVA and paired t-test at 0.05 level of significance. RESULTS: Results were not statistically significant. CONCLUSION: Within the limitations of the present study, cellphones do not interfere with the EWL determination.

The effect of temperature on rheological properties of endodontic sealers.

AIM: The purpose of this study was to investigate temperature-dependent rheological properties of three endodontic sealers MTA Fillapex (Angelus, Brazil), AH Plus (Dentsply, Germany), and EndoREZ (Ultradent, USA). MATERIALS AND METHODS: Five samples of each group of endodontic sealers (n = 30) were freshly mixed and placed on the plate of a rheometer (MCR 301, AntonPaar, Physica) and examined at 25°C and 37°C temperature, respectively. Rheological properties of the sealers were calculated according to the loss modulus (G″), storage modulus (G'), loss factor (Tan δ), and complex viscosity (η*) using dynamic oscillatory shear tests. RESULTS: Statistical analysis (Wilcoxon signed-rank test) demonstrated that MTA Fillapex exhibited higher loss modulus (G″ > G') and a crossover region. AH Plus and EndoREZ had a higher storage modulus (G' > G″) at both temperatures. Loss factor (Tan δ) of MTA Fillapex was the highest compared to AH Plus, followed by EndoREZ. With a temperature change from 25°C to 37°C, MTA Fillapex exhibited a decrease while AH Plus exhibited an increase and, EndoREZ exhibited the least change, in complex viscosity (η*). CONCLUSIONS: EndoREZ exhibited better rheological properties compared to the other two test sealers.

Pro-oncogenic Roles of HLXB9 Protein in Insulinoma Cells through Interaction with Nono Protein and Down-regulation of the c-Met Inhibitor Cblb (Casitas B-lineage Lymphoma b).

Pancreatic islet ß-cells that lack the MEN1-encoded protein menin develop into tumors. Such tumors express the phosphorylated isoform of the ß-cell differentiation transcription factor HLXB9. It is not known how phospho-HLXB9 acts as an oncogenic factor in insulin-secreting ß-cell tumors (insulinomas). In this study we investigated the binding partners and target genes of phospho-HLXB9 in mouse insulinoma MIN6 ß-cells. Co-immunoprecipitation coupled with mass spectrometry showed a significant association of phospho-HLXB9 with the survival factor p54nrb/Nono (54-kDa nuclear RNA-binding protein, non-POU-domain-containing octamer). Endogenous phospho-HLXB9 co-localized with endogenous Nono in the nucleus. Overexpression of HLXB9 decreased the level of overexpressed Nono but not endogenous Nono. Anti-phospho-HLXB9 chromatin immunoprecipitation followed by deep sequencing (ChIP-Seq) identified the c-Met inhibitor, Cblb, as a direct phospho-HLXB9 target gene. Phospho-HLXB9 occupied the promoter of Cblb and reduced the expression of Cblb mRNA. Cblb overexpression or HLXB9 knockdown decreased c-Met protein and reduced cell migration. Also, increased phospho-HLXB9 coincided with reduced Cblb and increased c-Met in insulinomas of two mouse models of menin loss. These data provide mechanistic insights into the role of phospho-HLXB9 as a pro-oncogenic factor by interacting with a survival factor and by promoting the oncogenic c-Met pathway. These mechanisms have therapeutic implications for reducing ß-cell proliferation in insulinomas by inhibiting phospho-HLXB9 or its interaction with Nono and modulating the expression of its direct (Cblb) or indirect (c-Met) targets. Our data also implicate the use of pro-oncogenic activities of phospho-HLXB9 in ß-cell expansion strategies to alleviate ß-cell loss in diabetes.

Consequence of Menin Deficiency in Mouse Adipocytes Derived by In Vitro Differentiation.

Lipoma in patients with the multiple endocrine neoplasia type 1 (MEN1) syndrome is a type of benign fat-cell tumor that has biallelic inactivation of MEN1 that encodes menin and could serve as a model to investigate normal and pathologic fat-cell (adipocyte) proliferation and function. The role of menin and its target genes in adipocytes is not known. We used in vitro differentiation to derive matched normal and menin-deficient adipocytes from wild type (WT) and menin-null (Men1-KO) mouse embryonic stem cells (mESCs), respectively, or 3T3-L1 cells without or with menin knockdown to investigate cell size, lipid content, and gene expression changes. Adipocytes derived from Men1-KO mESCs or after menin knockdown in 3T3-L1 cells showed a 1.5-1.7-fold increase in fat-cell size. Global gene expression analysis of mESC-derived adipocytes showed that lack of menin downregulated the expression of many differentially methylated genes including the tumor suppressor long noncoding RNA Meg3 but upregulated gene expression from the prolactin gene family locus. Our results show that menin deficiency leads to fat-cell hypertrophy and provide model systems that could be used to study the regulation of fat-cell size.

Comparative Evaluation of Fracture Resistance of Endodontically Treated Teeth Obturated with Resin Based Adhesive Sealers with Conventional Obturation Technique: An In vitro Study.

BACKGROUND: To compare fracture resistance of endodontically treated teeth obturated with different resin-based adhesive sealers with a conventional obturation technique. MATERIALS AND METHODS: A total of 60 Single canaled teeth were divided into five groups. The first group was taken as a negative control. The rest of the groups were shaped using ProFile rotary files (Dentsply Maillefer, Ballaigues, Switzerland). The second group was obturated with gutta-percha and a ZOE-based sealer Endoflas FS (Sanlor Dental Products, USA). The third group was obturated with gutta-percha and an epoxy-based sealer AH Plus (Dentsply, DeTrey, Germany). The fourth group was obturated with Resilon (Pentron Clinical Technologies, Wallingford, CT) and RealSeal sealer (Pentron Clinical Technologies). The fifth group was obturated with EndoREZ points and EndoREZ sealer (both from Ultradent, South Jordan, UT). Roots were then embedded into acrylic blocks and were then fixed into a material testing system and loaded with a stainless steel pin with a crosshead speed of 5 mm/min until fracture. The load at which the specimen fractured was recorded in Newtons. RESULTS: It was found that forces at fracture were statistically significant for the newer resin systems, Resilon, and EndoREZ. CONCLUSION: It was concluded that roots obturated with newer resin systems (Resilon and EndoREZ) enhanced the root strength almost up to the level of the intact roots.

Epigenetic regulation of the lncRNA MEG3 and its target c-MET in pancreatic neuroendocrine tumors.

Biallelic inactivation of MEN1 encoding menin in pancreatic neuroendocrine tumors (PNETs) associated with the multiple endocrine neoplasia type 1 (MEN1) syndrome is well established, but how menin loss/inactivation initiates tumorigenesis is not well understood. We show that menin activates the long noncoding RNA maternally expressed gene 3 (Meg3) by histone-H3 lysine-4 trimethylation and CpG hypomethylation at the Meg3 promoter CRE site, to allow binding of the transcription factor cAMP response element-binding protein. We found that Meg3 has tumor-suppressor activity in PNET cells because the overexpression of Meg3 in MIN6 cells (insulin-secreting mouse PNET cell line) blocked cell proliferation and delayed cell cycle progression. Gene expression microarray analysis showed that Meg3 overexpression in MIN6 mouse insulinoma cells down-regulated the expression of the protooncogene c-Met (hepatocyte growth factor receptor), and these cells showed significantly reduced cell migration/invasion. Compared with normal islets, mouse or human MEN1-associated PNETs expressed less MEG3 and more c-MET. Therefore, a tumor-suppressor long noncoding RNA (MEG3) and suppressed protooncogene (c-MET) combination could elicit menin's tumor-suppressor activity. Interestingly, MEG3 and c-MET expression was also altered in human sporadic insulinomas (insulin secreting PNETs) with hypermethylation at the MEG3 promoter CRE-site coinciding with reduced MEG3 expression. These data provide insights into the ß-cell proliferation mechanisms that could retain their functional status. Furthermore, in MIN6 mouse insulinoma cells, DNA-demethylating drugs blocked cell proliferation and activated Meg3 expression. Our data suggest that the epigenetic activation of lncRNA MEG3 and/or inactivation of c-MET could be therapeutic for treating PNETs and insulinomas.

GSK-3ß protein phosphorylates and stabilizes HLXB9 protein in insulinoma cells to form a targetable mechanism of controlling insulinoma cell proliferation.

Insulinomas (pancreatic islet ß cell tumors) are the most common type of functioning pancreatic neuroendocrine tumors that occur sporadically or as a part of the MEN1 syndrome that is caused by germ line mutations in MEN1. Tissue-specific tumor predisposition from germ line mutations in ubiquitously expressed genes such as MEN1 could occur because of functional consequences on tissue-specific factors. We previously reported the proapoptotic ß cell differentiation factor HLXB9 as a downstream target of menin (encoded by MEN1). Here we show that GSK-3ß inactivates the proapoptotic activity of HLXB9 by phosphorylating HLXB9 at Ser-78/Ser-80 (pHLXB9). Although HLXB9 is found in the nucleus and cytoplasm, pHLXB9 is predominantly nuclear. Both pHLXB9 and active GSK-3ß are elevated in ß cells with menin knockdown, in MEN1-associated ß cell tumors (insulinomas), and also in human sporadic insulinomas. Pharmacologic inhibition of GSK-3ß blocked cell proliferation in three different rodent insulinoma cell lines by arresting the cells in G2/M phase and caused apoptosis. Taken together, these data suggest that the combination of GSK-3ß and pHLXB9 forms a therapeutically targetable mechanism of insulinoma pathogenesis. Our results reveal that GSK-3ß and pHLXB9 can serve as novel targets for insulinoma treatment and have implications for understanding the pathways associated with ß cell proliferation.

Detection of Enterococcus faecalis and Candida albicans in previously root-filled teeth in a population of Gujarat with polymerase chain reaction.

BACKGROUND: Micro-organisms are the primary causative agents of endodontic infections. Phenotype based procedures for bacterial identification has certain drawbacks especially, when investigating the microbiota of root-filled teeth. Thus, more sensitive methods like Polymerase chain reaction (PCR) can provide results that are more accurate and reliable for the microbial prevalence in the root filled teeth. AIM: In this study, we have investigated twenty symptomatic root-filled teeth with chronic apical periodontitis for the prevalence of Enterococcus faecalis and Candida albicans in the root filled teeth associated with symptomatic cases with or without periradicular lesions. MATERIALS AND METHODS: Microbiological samples were taken from the canals immediately after removal of previous gutta percha cones using aseptic techniques. After removal of root canal filling, samples were obtained with paper points placed in the canal. Paper points were transferred to a cryotube containing "Tris EDTA" buffer and immediately frozen at -20°C. RESULTS: By PCR amplification of the samples using taxon specific primers, E. faecalis was found to be prevalent species, detected in 65% of the cases and C. albicans was detected in 35% of cases. CONCLUSION: The results of the study shows that geographical influence and dietary factors might have some role to play in the prevalence of the species like C. albicans and presence of E. faecalis confirming the assertion of previous culture-dependent and independent approaches for the microbiological survey of root filled teeth.

Germline and somatic mutations in cyclin-dependent kinase inhibitor genes CDKN1A, CDKN2B, and CDKN2C in sporadic parathyroid adenomas.

The molecular pathogenesis of sporadic parathyroid adenomas is incompletely understood. The possible role of cyclin-dependent kinase inhibitor (CDKI) genes was raised by recognition of cyclin D1 as a parathyroid oncogene, identification of rare germline mutations in CDKI genes in patients with multiple endocrine neoplasia type 1; that in rodents, mutation in Cdkn1b caused parathyroid tumors; and subsequently through identification of rare predisposing germline sequence variants and somatic mutation of CDKN1B, encoding p27(kip1), in sporadic human parathyroid adenoma. We therefore sought to determine whether mutations/variants in the other six CDKI genes CDKN1A, CDKN1C, CDKN2A, CDKN2B, CDKN2C, and CDKN2D, encoding p21, p57, p14(ARF)/p16, p15, p18, and p19, respectively, contribute to the development of typical parathyroid adenomas. In a series of 85 sporadic parathyroid adenomas, direct DNA sequencing identified alterations in five adenomas (6 %): Two contained distinct heterozygous changes in CDKN1A, one germline and one of undetermined germline status; one had a CDKN2B germline alteration, accompanied by loss of the normal allele in the tumor (LOH); two had variants of CDKN2C, one somatic and one germline with LOH. Abnormalities of three of the mutant proteins were readily demonstrable in vitro. Thus, germline mutations/rare variants in CDKN1A, CDKN2B, and CDKN2C likely contribute to the development of a significant subgroup of common sporadic parathyroid adenomas, and somatic mutation in CDKN2C further suggests a direct role for CDKI alteration in conferring a selective growth advantage to parathyroid cells, providing novel support for the concept that multiple CDKIs can play primary roles in human neoplasia.

The embryonic transcription factor Hlxb9 is a menin interacting partner that controls pancreatic ß-cell proliferation and the expression of insulin regulators.

The multiple endocrine neoplasia type 1 (MEN1) syndrome is caused by germline mutations in the MEN1 gene encoding menin, with tissue-specific tumors of the parathyroids, anterior pituitary, and enteropancreatic endocrine tissues. Also, 30-40% of sporadic pancreatic endocrine tumors show somatic MEN1 gene inactivation. Although menin is expressed in all cell types of the pancreas, mouse models with loss of menin in either pancreatic α-cells, or ß-cells, or total pancreas develop ß-cell-specific endocrine tumors (insulinomas). Loss of widely expressed tumor suppressor genes may produce tissue-specific tumors by reactivating one or more embryonic-specific differentiation factors. Therefore, we determined the effect of menin overexpression or knockdown on the expression of ß-cell differentiation factors in a mouse ß-cell line (MIN6). We show that the ß-cell differentiation factor Hlxb9 is posttranscriptionally upregulated upon menin knockdown, and it interacts with menin. Hlxb9 reduces cell proliferation and causes apoptosis in the presence of menin, and it regulates genes that modulate insulin level. Thus, upon menin loss or from other causes, dysregulation of Hlxb9 predicts a possible combined mechanism for ß-cell proliferation and insulin production in insulinomas. These observations help to understand how a ubiquitously expressed protein such as menin might control tissue-specific tumorigenesis. Also, our findings identify Hlxb9 as an important factor for ß-cell proliferation and insulin regulation.

Evaluation and comparison of efficacy of three different storage media, coconut water, propolis, and oral rehydration solution, in maintaining the viability of periodontal ligament cells.

BACKGROUND: Two of the most critical factors affecting the prognosis of an avulsed tooth after replantation are extra oral dry time and the storage medium in which the tooth is placed before treatment is rendered. However, the ability of a storage/transport medium to support cell viability can be more important than the extra oral time to prevent ankylosis and replacement resorption. AIM: Purpose of this study was evaluation and comparison of efficacy of a new storage medium, oral rehydration solution (ORS) with coconut water, and propolis in maintaining the viability of periodontal ligament (PDL) cells by using a collagenase-dispase assay. MATERIALS AND METHODS: 40 teeth were selected with intact crown which were advised for Orthodontic extraction having healthy PDL. Teeth were then randomly divided into three experimental storage solution groups. Other 10 were divided into positive and negative control groups (5 each). STATISTICAL ANALYSIS AND RESULT: The results were statistically analyzed with analysis of variance and multiple range by using post hoc tests. The results of the prevailing study indicated that coconut water group demonstrated a significantly higher number of viable PDL cells than propolis 50%, and ORS. There was no significant difference between coconut water and propolis 50% groups.

Comparative study of periapical radiographic techniques with apex locator for endodontic working length estimation: an ex vivo study.

BACKGROUND: Accurate assessment of working length determines the success and prognosis of an endodontic treatment outcome. Various methods are used in determining the working length. AIM: Compare the measurements of the apex locator and radiographic technique to determine working length. METHODS: An ex vivo study was conducted on 20 patients having intact single straight root canal. Only premolars were taken in the study. After doing coronal flaring and irrigation, the radiographic length was determined with an aid of a k-type file and electronic length (EL-Root-ZX) 3rd generation apex locator. After extraction of all the premolars, stereomicroscope was further used to confirm and compare radiographic and electronic apex locator. RESULTS: A mean value of 0.5430 ± 0.5741 mm was observed among radiographic techniques. A mean value of 0.4240 ± 0.4587 mm was observed among apex locator techniques. T-test revealed, no significant difference between the two techniques was observed (p = 0. 615). 'Two tailed' t-test revealed intragroup significance both techniques for determining the working length. CONCLUSION: The distance of the apical foramen to the tip of the file: A mean value of 0.4240 ± 0.4587 mm with apex locator technique was observed. Working length of apex locator was more in comparison to radiographic technique. No significant difference between the two techniques was observed (p = 0. 615). Intragroup significance among both techniques for determining the working length was also observed. However, a further study incorporating a larger sample size and utilization of both techniques of working length determination on the same tooth has to be conducted. CLINICAL SIGNIFICANCE: Combining the apex locator technique and radiographic technique for determination of working length would yield more accurate working length.