Histological artifacts associated with laser and electroscalpel gingivectomy: Case series

Introduction. Over time, efforts have been invested in the design of new instruments that overcome the disadvantages of the gold standard instrument in surgery, the scalpel. As a result, electronic equipment has emerged such as the electric scalpel and laser devices. The available evidence on these instruments suggests that the tissue response is related to each instrument’s physical and biological cutting principles. Objective. To compare the histological changes in gingiva samples associated with surgical cutting performed with a 940 nm diode laser, a 2780 nm erbium, chromium: yttriumscandium-gallium-garnet (Er,Cr:YSGG) laser, and an electric scalpel, by presenting a series of cases. Case presentation. We present three cases of healthy patients undergoing cosmetic surgery. The clinical examination revealed exposure of a keratinized gingiva band greater than 4 mm, normal color and texture in gingival tissue, with a firm consistency and no bleeding on periodontal probing. Gingivectomy was indicated with the following protocols: Diode laser of 940 nm at 1 W, in continuous mode; Er,Cr:YSGG laser of 2780 nm at 2.5 W, 75 Hz, H mode, air 20, water 40, gold tip MT4); and electric scalpel in cutting mode at power level four. Gingival tissue samples were taken and stored in 10% formaldehyde for histological analysis. Conclusion. All the evaluated cutting instruments generated histological changes produced by the thermal effect, the main ones being collagen coagulation and carbonization. The depth of thermal damage caused by the 2780 nm Er,Cr:YSGG laser was much lesser than that induced by the electric scalpel and the 940 nm diode laser.

Pivotal role of protein tyrosine phosphatase 1B (PTP1B) in the macrophage response to pro-inflammatory and anti-inflammatory challenge

Inhibition of protein tyrosine phosphatase 1B (PTP1B) has been suggested as an attractive target to improve insulin sensitivity in different cell types. In the present work, we have investigated the effect of PTP1B deficiency on the response of human and murine macrophages. Using in vitro and in vivo approaches in mice and silencing PTP1B in human macrophages with specific siRNAs, we have demonstrated that PTP1B deficiency increases the effects of pro-inflammatory stimuli in both human and rodent macrophages at the time that decreases the response to alternative stimulation. Moreover, the absence of PTP1B induces a loss of viability in resting macrophages and mainly after activation through the classic pathway. Analysis of early gene expression in macrophages treated with pro-inflammatory stimuli confirmed this exacerbated inflammatory response in PTP1B-deficient macrophages. Microarray analysis in samples from wild-type and PTP1B-deficient macrophages obtained after 24 h of pro-inflammatory stimulation showed an activation of the p53 pathway, including the excision base repair pathway and the insulin signaling pathway in the absence of PTP1B. In animal models of lipopolysaccharide (LPS) and D-galactosamine challenge as a way to reveal in vivo inflammatory responses, animals lacking PTP1B exhibited a higher rate of death. Moreover, these animals showed an enhanced response to irradiation, in agreement with the data obtained in the microarray analysis. In summary, these results indicate that, although inhibition of PTP1B has potential benefits for the treatment of diabetes, it accentuates pro-inflammatory responses compromising at least macrophage viability.

Mantle cell lymphoma: transcriptional regulation by microRNAs

Mantle cell lymphoma (MCL) pathogenesis is still partially unexplained. We investigate the importance of microRNA (miRNA) expression as an additional feature that influences MCL pathway deregulation and may be useful for predicting patient outcome. Twenty-three MCL samples, eight cell lines and appropriate controls were screened for their miRNAs and gene expression profiles and DNA copy-number changes. MCL patients exhibit a characteristic signature that includes 117 miRNA (false discovery rate <0.05). Combined analysis of miRNAs and the gene expression profile, paired with bioinformatics target prediction (miRBase and TargetScan), revealed a series of genes and pathways potentially targeted by a small number of miRNAs, including essential pathways for lymphoma survival such as CD40, mitogen-activated protein kinase and NF-kappaB. Functional validation in MCL cell lines demonstrated NF-kappaB subunit nuclear translocation to be regulated by the expression of miR-26a. The expression of 12 selected miRNAs was studied by quantitative PCR in an additional series of 54 MCL cases. Univariate analysis identified a single miRNA, miR-20b, whose lack of expression distinguished cases with a survival probability of 56% at 60 months. In summary, using a novel bioinformatics approach, this study identified miRNA changes that contribute to MCL pathogenesis and markers of potential utility in MCL diagnosis and clinical prognostication.