Expression and degranulation of mast cells in laser photobiomodulated mucositis chemo-induced: pilot study in hamsters.

This study aimed to evaluate the influence of laser photobiomodulation on the expression and degranulation of mast cells in chemo-induced oral mucositis (OM) lesions in hamsters. Twelve adult male Syrian hamsters (Mesocricetus auratus), golden lineage, were submitted to OM induction. They were divided into three groups: control-OM without treatment (C), OM treated with red laser (RL), OM treated with infrared laser (IL) and analyzed in the experimental time of 7 days. Three and 4 days after the intraperitoneal injection of the chemotherapy drug fluorouracil, the OM lesions were induced by making grooves in the right cheek pouch. Immediately after chemoinduction, the hamsters were submitted to photobiomodulation every 48 h for 7 days. The specimens were processed and stained using the hematoxylin-eosin and toluidine blue techniques. There was a predominance of mild chronic inflammation in the experimental groups and a greater persistence of neutrophils in the control group (C), although not statistically significant. The group irradiated with red laser (RL) had the highest mean mast cell expression (38.28 ± 19.05) (p < 0.001). As for the degranulation activity in mast cells, the control group (C) showed a greater number of fields with more than 50% of degranulated cells, presenting statistical significance when comparing it with the RL (p < 0.009) and IL (p = 0.036) group. It can be concluded that photobiomodulation, at both wavelengths, decreased mast cell degranulation, accelerating the inflammatory process. The use of infrared laser provided, in addition to less degranulation, the quantitative reduction of mast cells.

The role of tumor acidification in aggressiveness, cell dissemination and treatment resistance of oral squamous cell carcinoma.

AIMS: To investigate the role of tumor acidification in cell behavior, migration, and treatment resistance of oral squamous cell carcinoma (OSCC). MAIN METHODS: The SCC4 and SCC25 cell lines were exposed to acidified (pH 6.8) cell culture medium for 7 days. Alternatively, a long-term acidosis was induced for 21 days. In addition, to mimic dynamic pH fluctuation of the tumor microenvironment, cells were reconditioned to neutral pH after experimental acidosis. This study assessed cell proliferation and viability by sulforhodamine B and flow cytometry. Individual and collective cell migration was analyzed by wound healing, time lapse, and transwell assays. Modifications of cell phenotype, EMT induction and stemness potential were investigated by qRT-PCR, western blot, and immunofluorescence. Finally, resistance to chemo- and radiotherapy of OSCC when exposed to acidified environmental conditions (pH 6.8) was determined. KEY FINDINGS: The exposure to an acidic microenvironment caused an initial reduction of OSCC cells viability, followed by an adaptation process. Acidic adapted cells acquired a mesenchymal-like phenotype along with increased migration and motility indexes. Moreover, tumoral extracellular acidity was capable to induce cellular stemness and to increase chemo- and radioresistance of oral cancer cells. SIGNIFICANCE: In summary, the results showed that the acidic microenvironment leads to a more aggressive and treatment resistant OSCC cell population.

Argyrophilic nucleolar organizer regions in oral mucosa cells of crack and cocaine users: a cross-sectional study.

The objective of this study was to analyze and compare the presence of argyrophilic nucleolar organizer regions (AgNORs) in exfoliated cells obtained from the buccal mucosa among crack and cocaine users and non-users by the AgNOR staining technique. Seventy-three males ≥ 18 years were categorized into two groups: 38 crack and/or cocaine users and 35 non-user volunteers. They were interviewed and responded a questionnaire regarding general health and drug addiction. Exfoliative cytology specimens were collected from the clinically intact buccal mucosa, and cytological preparations were fixed and stained by AgNOR technique. The mean number of AgNORs (p = 0.02) and the percentage of epithelial cells with more than 3 (p = 0.01) and 4 (p = 0.04) AgNORs/nucleus were significantly higher in the non-user group. In conclusion, the frequency and diversity of substances present in the drugs-cocaine, crack, and alcohol-consumed by the volunteers of this study may have influenced the number of AgNORs and the response to damage and consequent effect on protein synthesis.

Pericoronal follicles revealing unsuspected odontogenic cysts and inflammatory lesions: A retrospective microscopy study.

AIM: This study aimed to analyze the prevalence of diseases related to pericoronal follicles, and assess the rate of concordance between clinical and histopathological diagnoses. METHODS: Histologically, we analyzed 1,298 tissue samples surrounding the crowns of teeth that were diagnosed clinically as pericoronal follicles. In addition, we determined associations among histopathological diagnosis, patients' age and sex, tissue site, presence of nests of odontogenic epithelium, presence of reduced enamel epithelium, and presence of diffuse inflammation. RESULTS: Odontogenic pathologies were present in 35% of the samples, and rate of concordance between clinical and histopathological diagnoses was 0.54. Probability of developing odontogenic pathologies was high in the mandibular molars (odds ratio: 2.13) and in the tissues with odontogenic epithelial remnants (odds ratio: 1.2), reduced enamel epithelium (odds ratio: 1.3), and diffuse inflammation. (odds ratio: 10.5). CONCLUSIONS: The findings of this study highlight the clinical relevance of histopathological examination of the pericoronal tissue in unerupted and partially erupted teeth for early diagnosis of pathologies because this study demonstrated the odontogenic cysts and inflammatory lesions in tissues clinically diagnosed as pericoronal follicles.

Effects of extracellular acidity on resistance to chemotherapy treatment: a systematic review.

Metabolic alterations in the tumor microenvironment have a complex effect on cancer progression. Extracellular acidity is a consequence of metabolic switch in cancer and results in cell phenotypes with higher resistance to chemotherapeutics. However, mechanisms underlying the relationship between the extracellular acidity and chemoresistance are not clearly understood. This systematic review was carried out by searching the databases PubMed and EMBASE using the keywords "cancer" and "acidosis" or "acidic" and "chemoresistance" or "drug resistance." In vitro and in vivo studies that evaluated the effects of acidification of the tumor microenvironment on chemotherapeutic treatments were included. Literature reviews, letters to the editor, and articles that were not published in English were excluded. The search resulted in a total of 352 articles. After discarding 75 duplicate references, 277 articles were analyzed by sequentially reading through their titles, abstracts, and finally full-text. A total of 14 articles was selected. Acidification of the tumor microenvironment can trigger resistance through different mechanisms, such as increase in drug efflux transporters, inhibition of proton pumps, induction of the unfolded protein response (UPR), and cellular autophagy.

Oral Lesions in Pycnodysostosis Syndrome: Eleven Years of Follow-Up.

Pycnodysostosis is a rare genetic disease that is characterized by osteosclerosis, short stature, and bone fragility. There are not cases of gnathic bones lesions reported on the international literature. This study aims to describe a clinical case of a 10-year-old girl with pycnodysostosis syndrome and an uncommon association with 4 distinct lesions (dentigerous cyst, central giant cell lesions, and 2 fibro-osseous lesions).

The importance of histopathologic analysis of pericoronal follicles for the early identification of ameloblastomas.

The objective of this study was to discuss the importance of performing histopathological examination of pericoronal follicles as a routine procedure, so as to enable the early identification of odontogenic lesions. We describe two clinical cases with histopathological diagnoses of ameloblastomas who did not show clinical or radiographic signs of disease before microscopic examination.