Solitary neurofibroma of the floor of the mouth: rare localization at lingual nerve with intraoral excision.

BACKGROUND: Neurofibromas (NF) are benign tumors of the peripheral nerves that are composed of Schwann cells, perineural-like cells and fibroblasts. The differential diagnosis for a solitary intraneural variant of neurofibroma arising in the floor of the mouth is broad and includes a submandibular gland neoplasm and adenopathy, among others. The intraoral approach is the best choice for a medium-sized lesion. CASE PRESENTATION: We report a rare case of a solitary neurofibroma of the floor of the mouth in a 31-year-old male. The patient consulted the dental emergency department for acute pain of the left mandible. Systematic clinical examination revealed the presence of a mass in the left mouth floor. The panoramic x-ray was not conclusive and the magnetic resonance imaging (MRI) revealed a well-defined soft tissue lesion with homogenous isosignal intensity on the T1-weighted image, high intensity signal on the T2-weighted image and heterogeneous enhancement following contrast-enhancement on the T1-weighted Fast Sat image. The surgical excision of the soft-tissue neoplasm was accomplished by an intraoral approach. The specimen was sent for histopathologic analysis and Immunohistochemical studies which confirmed the diagnosis of a myxoid predominant intraneural solitary neurofibroma. CONCLUSION: The diagnosis of neurofibroma was confirmed by histopathological evaluation and immunohistochemical studies which also excluded other entities in the histopathologic differential diagnosis including schwannoma and a malignant peripheral nerve sheath tumor among other. Localized (solitary) neurofibromas most often occur as sporadic lesions, however; diagnosis of a solitary neurofibroma prompts clinical evaluation to exclude the remote possibility of neurofibromatosis. The purpose of this case report is to raise awareness of the uncommon presentation of neurofibroma and to document the successful management of such a lesion using an intraoral approach.

Antimicrobial peptide gene expression in periodontitis patients: A pilot study.

AIM: Antimicrobial peptides (AMPs) are one of the most active components of innate immunity and have characteristics that could place them at the heart of the pathogenesis of periodontal disease. This study investigated differences in the expression of AMP coding genes obtained using a simple harvesting technique, gingival smear, between two groups of patients: chronic periodontitis subjects versus healthy ones. MATERIALS AND METHODS: Twenty-three patients were enrolled in two groups: 12 were diagnosed with moderate or severe generalized chronic periodontitis, and 11 were diagnosed as clinically healthy. Gingival smears were retrieved and studied using reverse transcription-quantitative PCR (RT-qPCR) after mRNA purification. RESULTS: Fifteen gene expressions were obtained using real-time RT-qPCR. Three AMP genes, histatin 3 (HTN3), α-defensin 4 (DEFA4) and lysozyme C (LYZ), presented different expression levels in periodontitis patients compared with healthy subjects. The relative expression level of DEFA4 appeared to be a protective factor against periodontitis. CONCLUSION: Gingival smears studied by RT-qPCR may be used to assess the expression of AMPs coding genes. A lack of expression of DEFA4 could be a potential indicator of periodontitis status.

Immunohistochemical study of DNA topoisomerase I, DNA topoisomerase II alpha, p53, and Ki-67 in oral preneoplastic lesions and oral squamous cell carcinomas.

Human DNA topoisomerase I (topo I) is the molecular target of the camptothecin group of anticancer drugs. Laboratory studies have shown that the cellular response to topo I-targeted drugs depends on the topo I expression and DNA replication rate and the apoptotic pathway activity. In this study, we tested potential indicators of the sensitivity of topo I-targeted drugs in 36 cases of oral squamous cell carcinoma (OSCC). Formalin-fixed, paraffin-embedded tissue sections were immunostained with monoclonal antibodies against Ki-67, p53, and topo I, and with polyclonal antibodies against DNA topoisomerase II-alpha (topo II-alpha). These markers were also tested in 18 epithelial hyperplastic lesions and 18 mild dysplasias. Immunostaining was quantified by the percentage of stained nuclei in each sample (the labeling index); 200 immunoreactive epithelial nuclei were counted per case for each antibody. The results support the possibility of using topo II-alpha staining for assessing the proliferative activity. High expression of topo II-alpha and topo I in OSCCs suggests that they may serve as potential indicators of sensitivity to topo I inhibitors. However, the apoptotic pathway assessed by p53 immunostaining was found to be uninformative. Analysis of the relationship between immunohistochemical results and clinical and pathologic parameters (the T and N stages and differentiation) showed that only the differentiation parameter correlated with the topo I expression rate. Thus, significant increase in the topo I expression in the poorly differentiated OSCCs suggests their higher sensitivity to drug treatment.

Fractionation and removal of dissolved organic carbon in a full-scale granular activated carbon filter used for drinking water production.

The removal of natural organic matter (NOM) and, more particularly, its individual fractions by two different GACs was investigated in full-scale filters in a drinking water treatment plant (DWTP). Fractionation of NOM was performed by high performance size exclusion chromatography (HPSEC) into biopolymers, humic substances, building blocks and low molecular weight organics. The sorption capacity of GAC in terms of iodine number (IN) and apparent surface area (SBET), as well as the filling of narrow- and super-microporosity were monitored over the 1-year operation of the filters. Both GACs demonstrated to be effective at removing NOM over a wide range of fractions, especially the low and intermediate molecular weight fractions. TOC removal initially occurred via adsorption, and smaller (lighter) fractions were more removed as they could enter and diffuse more easily through the pores of the adsorbent. As time progressed, biodegradation also played a role in the TOC removal, and lighter fractions continued to be preferentially removed due to their higher biodegradability. The gained knowledge would assist drinking water utilities in selecting a proper GAC for the removal of NOM from water and, therefore, complying more successfully the latest water regulations.

Characterising biofilm development on granular activated carbon used for drinking water production.

Under normal operation conditions, granular activated carbon (GAC) employed in drinking water treatment plants (DWTPs) for natural organic matter (NOM) removal can be colonised by microorganisms which can eventually establish active biofilms. The formation of such biofilms can contribute to NOM removal by biodegradation, but also in clogging phenomena that can make necessary more frequent backwashes. Biofilm occurrence and evolution under full-scale-like conditions (i.e. including periodic backwashing) are still uncertain, and GAC filtration is usually operated with a strong empirical component. The aim of the present study was to assess the formation and growth, if any, of biofilm in a periodically backwashed GAC filter. For this purpose, an on-site pilot plant was assembled and operated to closely mimic the GAC filters installed in the DWTP in Sant Joan Despí (Barcelona, Spain). The study comprised a monitoring of both water and GAC cores withdrawn at various depths and times throughout 1 year operation. The biomass parameters assessed were total cell count by confocal laser scanning microscopy (CLSM), DNA and adenosine triphosphate (ATP). Visual examination of GAC particles was also conducted by high-resolution field emission scanning electron microscopy (FESEM). Additionally, water quality and GAC surface properties were monitored. Results provided insight into the extent and spatial distribution of biofilm within the GAC bed. To sum up, it was found that backwashing could physically detach bacteria from the biofilm, which could however build back up to its pre-backwashing concentration before next backwashing cycle.