Mesenchymal adipose stem cells maintain the capacity for differentiation and survival in culture beyond the long term.

Mesenchymal cells (MSCs) are considered to be cellular populations of common embryological origin. For clinical research applications, MSCs are expanded and increased with cells obtained from a primary culture. By extracting cells from tissue and encouraging them to reproduce, the stem cell population ends up dominating the culture due to a high proliferation rate and self-renewal. The first subcultures between the third and sixth are chosen in order to obtain the maximum number of cells with optimal differentiation capacity. However, few studies have reported long-term cultivation of MSCs. The objective of this study was to advance the knowledge on the characteristics of MSCs by assessing their capacity for self-renewal and phenotypic maintenance beyond 50 cell subcultures, which is defined as the normal limit for cellular survival. Rat subcutaneous adipose tissue was the source of mesenchymal adipose stem cells (MASCs) cultured over 175 subcultures. Early 1 to 5 and late 25 to 30 subcultures were used to induce cellular differentiation to become adipogenic, chondrogenic and osteogenic connective tissue cells. MASCs characteristics were studied using flow cytometry, transmission electron microscopy (TEM), and immunohistochemical and reverse transcription polymerase chain reaction (RT-qPCR) assays. The MASCs maintained cell differentiation capacity for more than 30 subcultures but lost potentiality starting at 60 up to 175 subcultures. MASCs showed the embryonic phenotypes OCT3/4 and Nanog indefinitely, and developed compensatory mechanisms, such as autophagy, to achieve cell survival over a long time period. Therefore, long-term subcultures showed that MASCs could maintain their potential for clinical research use.

Concerns, Knowledge, and Practices of Dentists in Mexico Regarding Infection Control during the Coronavirus Disease Pandemic: A Cross-Sectional Study.

Dentists are highly exposed and vulnerable during the coronavirus disease (COVID-19) pandemic, as physical proximity to patients is necessary for effective dental examination and treatment. The objective of this study was to describe the concerns, knowledge, and infection control practices of dentists in Mexico during the COVID-19 pandemic. In this cross-sectional study conducted from 22 May 2020 to 8 July 2020, an anonymous survey was distributed to dentists, which covered information regarding dentists' sociodemographic and professional characteristics, clinical practices during the pandemic, and perceptions regarding the application of infection prevention and control guidance for dental settings during the COVID-19 pandemic. Out of 703 respondents, 73.1% (n = 514) were women and 53.6% (n = 377) were dentists with 1-10 years of experience. Regarding the statements issued by the World Health Organization (WHO) and the Centers for Disease Control and Prevention (CDC), the responses for 11 survey items had total agreement rates >90% (high frequency); seven and nine items had moderate and low frequency of total agreement, respectively. Most dentists in this study agreed with the WHO and CDC statements and were concerned regarding the possibility of infection, despite using the protective gear.

LncRNA SOX2-OT regulates AKT/ERK and SOX2/GLI-1 expression, hinders therapy, and worsens clinical prognosis in malignant lung diseases.

The involvement of LncRNA SOX2-overlapping transcript (SOX2-OT), SOX2, and GLI-1 transcription factors in cancer has been well documented. Nonetheless, it is still unknown whether co-expressed SOX2-OT/SOX2 or SOX2-OT/SOX2/GLI-1 axes are epigenetically/transcriptionally involved in terms of resistance to oncology therapy and in poorer clinical outcomes for patients with lung cancer. We evaluated the role of SOX2-OT/SOX2 and SOX2-OT/SOX2/GLI-1 axes using RT-qPCR, western blot, immunofluorescence analyses, gene silencing, cellular cytotoxic, and ChIP-qPCR assays on human cell lines, solid lung malignant tumors, and normal lung tissue. We detected that the SOX2-OT/SOX2/GLI-1 axis promotes resistance to tyrosine kinase inhibitor (TKI)-erlotinib and cisplatin-based therapy. Evidence from this study show that SOX2-OT modulates the expression/activation of EGFR-pathway members AKT/ERK. Further, both SOX2-OT and GLI-1 genes are epigenetically regulated at their promoter sequences, in an LncRNA SOX2-OT-dependent manner, mainly through modifying the enrichment of the activation histone mark H3K4me3/H3K27Ac, versus the repressive histone mark H3K9me3/H3K27me3. In addition, we identified that inhibition of SOX2-OT and reduced expression of SOX2/GLI-1 sensitizes lung cancer cells to EGFR/TKI-erlotinib or cisplatin-based treatment. Finally, we show that high co-expression of SOX2-OT/SOX2 transcripts and SOX2/GLI-1 proteins appears to correlate with a poor clinical prognosis and lung malignant phenotype. Collectively, these results present evidence that LncRNA SOX2-OT modulates an orchestrated resistance mechanism, promoting poor prognosis and human lung malignancy through genetic, epigenetic, and post-translational mechanisms.

Sublingual dermoid cyst in an infant: A case report and review of the literature.

Dermoid cysts usually occur later in the second decade of life; we present the approach of an unusual case of an infant who presented a cyst within the oral cavity, which is important because it can be confused with other pathologies.

PD-1, TIM-3, and LAG-3 Expression in T Cells in a Patient with Recurrent Ossifying Fibroma: A Case Report.

Central ossifying fibroma is a benign, slow-growing tumor of mesenchymal origin with a predilection for the mandibular premolar and molar areas. The immunophenotype of T cells involved in the antitumor response against this benign tumor is unknown. In this case report, we described a case of a 48-year-old woman presenting with a very large recurrent ossifying fibroma in the mandible, which was successfully treated with hemimaxillectomy. In addition, we evaluated the expression of programmed cell death 1 receptor (PD-1), lymphocyte activation gene-3 (LAG-3), T cell immunoglobulin and mucin-domain containing-3 (TIM-3), cytotoxic T lymphocyte-associated antigen-4 (CTLA-4), CD69 (activation inducer molecule), and CD25 (α chain of the high-affinity IL-2 receptor) in T cell populations from the tumor and peripheral blood of this uncommon lesion. The patient presented recurrent ossifying fibroma, and the tumor-infiltrating and peripheral blood T cells showed expression of PD-1, LAG-3, and TIM-3, suggesting an exhausted T cell response.

Correlation between caries history and laser fluorescence of sound tooth enamel in restored and unrestored dentition.

The aim of this study was to determine the correlation between laser fluorescence (LF) values of apparently sound tooth enamel and caries history. LF measurements were recorded from six sound enamel tooth surfaces in each of 346 subjects aged 8-25 years. Caries experience was evaluated using the decayed, missing, and filled tooth (DMFT) index and the International Caries Detection and Assessment System (ICDAS). To measure differences between the unrestored and restored tooth groups, an unpaired two-sample t-test was used. To assess the relationship between LF of sound enamel and caries experience based on the DMFT and ICDAS, Pearson's correlation coefficient and linear regression analyses were used. The LF values of sound dental enamel in subjects with no history of invasive dental treatment were highly correlated with caries experience, as measured by the DMFT index (R = 0.76) and ICDAS (R = 0.7). The LF values of sound enamel in subjects with a history of previous invasive dental treatment were weakly correlated with caries experience, as measured by the DMFT index (R = 0.33), and moderately correlated with the ICDAS values (R = 0.66). The LF value of clinically healthy tooth enamel correlates with caries status based on the DMFT or ICDAS.

Evaluation of bone regeneration in a critical size cortical bone defect in rat mandible using microCT and histological analysis.

GOAL: Evaluate bone regeneration in a critical size bone defect model in the jaw of healthy rats as a function of gender and defect location. DESIGN: A series of microCT and histological studies were performed to evaluate the process of bone regeneration in rats with a mandibular critical size defect. Rats were placed in two groups according to gender and sorted in terms of bone defect location. Bone regeneration rate and hydroxyapatite concentration were assessed with microCT imaging at specific times after surgery. Histological analysis was also performed to evaluate bone regeneration. RESULTS: No more that 85% of bone regeneration was observed after 60 days, with a low rate constant (K) indicating a slow restoration of the defect. Assessment of microCT images showed partial closure of the defect in all cases, which was confirmed by histological analysis. Hydroxyapatite concentration values revealed that regenerated bone was not fully calcified. No statistically significant differences in terms of gender or defect location were found. CONCLUSION: The defect model studied here, located in the jaw of healthy rats, shows potential as a preclinical critical size bone defect model to evaluate bone regeneration therapies in the fields of dentistry and maxillofacial surgery.

Análisis de la relación entre la hipomineralización incisivo molar y los factores asociados a su etiología / Analysis of the relationship between molar incisor hypomineralization and the factors associated with its etiology

RESUMEN El objetivo de este artículo es analizar la relación entre la hipomineralización incisivo molar (HIM) y los factores asociados a su etiología publicados en la literatura. Material y métodos: El estudio se basó en una búsqueda de estudios epidemiológicos de casos y controles de HIM que describieron un factor etiológico asociado para obtener las odds ratio (OR) necesarias para analizar la prevalencia del factor afectado y su posible papel en la etiología de la condición. Resultados: Ocho artículos cumplieron los criterios para el análisis. La población total analizada consistió en una muestra de 7,901 sujetos, de los cuales 992 tenían HIM. En estos sujetos fueron reportados como factor asociado (FA) para HIM: asma (OR = 4.4954), uso de antibióticos (OR = 5.5348), fiebre (OR = 4.0545) y neumonía. Conclusión: Los resultados del presente estudio sugieren que un FA común a todos los casos de HIM estudiados es un proceso inflamatorio que conduce a una mayor concentración de agentes en el microambiente en el que se desarrollan las células formadoras del esmalte, lo que aumenta la presencia de proteínas en la matriz del esmalte o interfieren con su hidrólisis y eliminación y produce como resultado una deficiente mineralización.

ABSTRACT Hypomineralization enamel of the first permanent molars is the most common developmental abnormalities observed in the teeth. The aetiology of MIH remains unclear and may have a multifactor aetiology. The aim of this paper is to analyze the relationship between MIH and associated factors published in the literature. Material and methods: The study was based on a search for epidemiological case-control studies of MIH that described an associated etiological factor, in order to obtain the odds ratios needed to analyze the prevalence of the factor concerned and its possible role in the etiology of the condition. Results: The initial search produced 50 articles, eight of which met the criteria for the analysis. The total population analyzed consisted of a sample of 7,901 subjects, 992 of whom had MIH (i.e., a prevalence of 12.55%). Asthma was reported as an etiological factor in five papers, which included 474 subjects with MIH with an OR of 4.4954 (p < 0.0001). Antibiotic use was reported as an etiological factor in three papers, which reported on a population of 231 subjects with MIH and OR of 5.5348 (p < 0.0001). Fever was reported as an etiological factor in two papers, involving a population of 176 subjects with MIH and an OR of 4.0545 (p < 0.0001). Pneumonia was reported as an etiological factor in two papers, which dealt with a population of 454 cases of MIH and produced an OR of 2.285 (p < 0.0001). Conclusion: The results of the present study suggest that one etiological factor common to all of the MIH cases studied is an infl ammatory process, in which the presence of agents that cause alterations in ameloblasts can lead to higher concentrations of these agents in the microenvironment in which enamel forming cells develop, thus increasing the presence of proteins in the enamel matrix or interfering with their hydrolysis and removal, producing defects in enamel mineralization.

Aislamiento de células mesenquimales del ligamento periodontal de premolares extraídos. Método simplificado / Isolation of periodontal ligament stem cells from extracted premolars. Simplified method

Resumen: El ligamento periodontal es un tejido conectivo fibroso, de origen ectomesenquimal que contiene una población de células troncales postnatales multipotenciales, con capacidad clonogénica y alto índice de proliferación. Se ha conseguido cultivar células troncales postnatales multipotenciales a través de diferentes métodos de extracción, con algunos problemas técnicos. Por esta razón, se compararon seis diferentes métodos a fin de mejorar el aislamiento de células primarias del ligamento periodontal. Se aislaron células troncales postnatales multipotenciales a partir de 36 premolares sanos, que se cultivaron en medio de Eagle modificado por Dulbecco (BioWest) completo (adicionado con L-glutamina, 10% de suero fetal bovino y 1% de antibiótico) y en condiciones estándares de cultivo. Se realizaron los ensayos para proliferación celular mediante la técnica de 3-(4,5-dimetiltiazol-2-il)-2,5difeniltetrazolio, migración celular a través de la prueba de lesión del cultivo, y se evaluó su diferenciación osteogénica. Los cultivos realizados por triplicado con cada una de las técnicas publicadas, nos condujo a obtener una población mínima de células que fueron susceptibles a contaminarse. Se realizó con el «método simplificado¼: por digestión enzimática y cultivo de explantos, con las células troncales postnatales multipotenciales obtenidas se observó una proliferación durante 14 días en condiciones estándares de cultivo ascendente, en las pruebas de migración las células troncales postnatales multipotenciales cubrieron totalmente la superficie lesionada a las 72 horas, se observó expresión positiva de CD90 en más del 80% de las células; expresión positiva a CD73 en un 70%, CD105 en un 60% y vimentina en un 90% de la población, así como un marcaje negativo a CD11b y CD45. Se observó una diferenciación osteogénica positiva a los 14 días mediante la expresión positiva a RUNX2 en al menos el 15% de las células y a osteocalcina en un 90%, así como las pruebas positivas a rojo de alizarina. Con los resultados obtenidos, podemos afirmar que el método simplificado permite aislar una población de células mesenquimales, que se pueden obtener a partir de premolares sanos extraídos.

Abstract: Periodontal ligament is a fibrous connective tissue of ectomesenchymal origin which contains a multipotent postnatal stem cells population with clonogenic capacity and high proliferation index. Multipotent postnatal stem cells population culture has been achieved through several extraction methods, nevertheless some technical problems have been encountered. For this reason, in the present study, 6 different methods were compared so as to improve isolation of primary periodontal ligament cells. Multipotent postnatal stem cells population were isolated from 36 healthy premolars, which were then cultured in complete Dulbecco m odified Eagle medium (BioWest) (added with L-glutamine, 10% fetal bovine serum and 1% antibiotic), in standard culture conditions. Assays for cell proliferation were conducted with 3-(4,5 dimethylthiazol-2-yl)-2,5 diphenyltetrazolium technique as well as cell migration through crop injury test, after which osteogenic differentiation was assessed. Cultures were performed in triplicate with each of the published techniques; thus we were able to obtain a minimum population of cells susceptible to contamination. The «simplifled method¼ was conducted through explant enzymatic digestion and culture: with obtained multipotent postnatal stem cells population, a 14 day proliferation was observed in standard conditions of ascendant culture; in migration tests, multipotent postnatal stem cells population totally covered injured surfaces after 72 hours. CD90 positive expression was observed in over 80% of all cells; CD73 positive expression was found in 70% of cells, CD105 in 60% and vimentin in 90% of the population, as well as negative marking to CD11b and CD45. Positive osteogenic differentiation was observed after 14 days, through positive expression to RUNX2 in at least 15% of cells, and to osteocalcin in 90% as well as positive test to alizarin red. Based on obtained results we were able to affirm that the simplified method allows to isolate a population of mesenchymal cells, which might be obtained from extracted healthy premolars.