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.

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.