Room-temperature highly sensitive and selective NH3gas sensor using vertically aligned WS2nanosheets.

Here, we report the room temperature (35 °C) NH3gas sensor device made from WS2nanosheets obtained via a facile and low-cost probe sonication method. The gas-sensing properties of devices made from these nanosheets were examined for various analytes such as ammonia, ethanol, methanol, formaldehyde, acetone, chloroform, and benzene. The fabricated gas sensor is selective towards NH3and exhibits excellent sensitivity, faster response, and recovery time in comparison to previously reported values. The device can detect NH3down to 5 ppm, much below the maximum allowed workspace NH3level (20 ppm), and have a sensing response of the order of 112% with a response and recovery time of 54 s and 66 s, respectively. On the other hand, a sensor made from nanostructures has a bit longer recovery time than a device made from nanosheets. This was attributed to the fact that NH3molecules adsorbed on the surface site and those trapped in between WS2layers may have different adsorption energies . In the latter case, desorption becomes difficult and may give rise to slower recovery as noticed. Further, stiffened Raman modes upon exposure to NH3reveal strong electron-phonon interaction between NH3and the WS2channel. The present work highlights the potential use of scaled two-dimensional nanosheets in sensing devices and particularly when used with inter-digitized electrodes, may offer enhanced performance.

Characterization of Transgenic NSG-SGM3 Mouse Model of Precision Radiation-Induced Chronic Hyposalivation.

Regenerative medicine holds promise to cure radiation-induced salivary hypofunction, a chronic side effect in patients with head and neck cancers, therefore reliable preclinical models for salivary regenerative outcome will promote progress towards therapies. In this study, our objective was to develop a cone beam computed tomography-guided precision ionizing radiation-induced preclinical model of chronic hyposalivation using immunodeficient NSGSGM3 mice. Using a Schirmer's test based sialagogue-stimulated saliva flow kinetic measurement method, we demonstrated significant differences in hyposalivation specific to age, sex, precision-radiation dose over a chronic (6 months) timeline. NSG-SMG3 mice tolerated doses from 2.5 Gy up to 7.5 Gy. Interestingly, 5-7.5 Gy had similar effects on stimulated-saliva flow (∼50% reduction in young female at 6 months after precision irradiation over sham-treated controls), however, >5 Gy led to chronic alopecia. Different groups demonstrated characteristic saliva fluctuations early on, but after 5 months all groups nearly stabilized stimulated-saliva flow with low-inter-mouse variation within each group. Further characterization revealed precision-radiation-induced glandular shrinkage, hypocellularization, gland-specific loss of functional acinar and glandular cells in all major salivary glands replicating features of human salivary hypofunction. This model will aid investigation of human cell-based salivary regenerative therapies.

Deep hypothermic extracorporeal membrane oxygenation cannula exchange in a child with necrotic pneumonia.

Necrotizing pneumonia can lead to respiratory insufficiency in previously healthy children. Extracorporeal membrane oxygenation can be used for hemodynamic salvage and subsequent lung rest awaiting recovery. We present a case of a child initially placed on veno-arterial extracorporeal membrane oxygenation and converted to veno-venous extracorporeal membrane oxygenation. This was done under deep hypothermia in the operating theater.

White oral mucosal lesions among the Yemeni population and their relation to local oral habits.

AIMS: The aim of the present study was to assess the prevalence and risk factors of white oral mucosal lesions among Yemeni adults; in particular, those who chew khat and tobacco. METHODS: The present cross-sectional study included 1052 dental patients aged 15 years and older. A detailed oral examination was performed by a single examiner in accordance with standard international criteria. RESULTS: Overall, 25.2% of the study participants presented with one or more white lesions. The most prevalent lesions were khat-induced white lesion (8.8%), leukoedema (5.1%), and frictional keratosis (3.9%). Potentially malignant lesions, such as lichen planus, leukoplakia, and smokeless tobacco-induced lesions, were seen in 2.4%, 1.2%, and 1.7% of participants, respectively. Moreover, three cases of oral cancer were identified. The presence of white lesions was found to be significantly associated with advanced age (P = .004), male gender (P = .009), and khat/tobacco chewing habits (P < .001). CONCLUSIONS: The present study demonstrates a high prevalence of oral benign and potentially malignant white lesions. Further, it highlights the urgent need to develop and implement new government policies to regulate the sale of these products to reduce the prevalence of these lesions and the overall incidence of oral cancers in the Yemeni population.

Prospects in the Application of Photodynamic Therapy in Oral Cancer and Premalignant Lesions.

Oral cancer is a global health burden with significantly poor survival, especially when the diagnosis is at its late stage. Despite advances in current treatment modalities, there has been minimal improvement in survival rates over the last five decades. The development of local recurrence, regional failure, and the formation of second primary tumors accounts for this poor outcome. For survivors, cosmetic and functional compromises resulting from treatment are often devastating. These statistics underscore the need for novel approaches in the management of this deadly disease. Photodynamic therapy (PDT) is a treatment modality that involves administration of a light-sensitive drug, known as a photosensitizer, followed by light irradiation of an appropriate wavelength that corresponds to an absorbance band of the sensitizer. In the presence of tissue oxygen, cytotoxic free radicals that are produced cause direct tumor cell death, damage to the microvasculature, and induction of inflammatory reactions at the target sites. PDT offers a prospective new approach in controlling this disease at its various stages either as a stand-alone therapy for early lesions or as an adjuvant therapy for advanced cases. In this review, we aim to explore the applications of PDT in oral cancer therapy and to present an overview of the recent advances in PDT that can potentially reposition its utility for oral cancer treatment.

Molecular characterization of immortalized normal and dysplastic oral cell lines.

BACKGROUND: Cell lines have been developed for modeling cancer and cancer progression. The molecular background of these cell lines is often unknown to those using them to model disease behaviors. As molecular alterations are the ultimate drivers of cell phenotypes, having an understanding of the molecular make-up of these systems is critical for understanding the disease biology modeled. METHODS: Six immortalized normal, one immortalized dysplasia, one self-immortalized dysplasia, and two primary normal cell lines derived from oral tissues were analyzed for DNA copy number changes and changes in both mRNA and miRNA expression using SMRT-v.2 genome-wide tiling comparative genomic hybridization arrays, Agilent Whole Genome 4x44k expression arrays, and Exiqon V2.M-RT-PCR microRNA Human panels. RESULTS: DNA copy number alterations were detected in both normal and dysplastic immortalized cell lines-as well as in the single non-immortalized dysplastic cell line. These lines were found to have changes in expression of genes related to cell cycle control as well as alterations in miRNAs that are deregulated in clinical oral squamous cell carcinoma tissues. Immortal lines-whether normal or dysplastic-had increased disruption in expression relative to primary lines. All data are available as a public resource. CONCLUSIONS: Molecular profiling experiments have identified DNA, mRNA, and miRNA alterations for a panel of normal and dysplastic oral tissue cell lines. These data are a valuable resource to those modeling diseases of the oral mucosa, and give insight into the selection of model cell lines and the interpretation of data from those lines.

Cytotoxicity evaluation of a new fast set highly viscous conventional glass ionomer cement with L929 fibroblast cell line.

AIM: This study aims to evaluate the cytotoxicity of a new fast set highly viscous conventional glass ionomer cement (GIC) with L929 fibroblasts. MATERIALS AND METHODS: The cement capsule was mixed and introduced into a paraffin wax mould. After setting, the cement was incubated in Dulbecco's Modified Eagle's Medium. Six replicates of the material extract were added to the culture medium in 96-well plates. L929 mouse fibroblast cells were added into the wells and then incubated for 48 h. Dimethylthiazol diphenyltetrazolium bromide test was performed for cytotoxicity evaluation. RESULTS: The results showed that this GIC brand did not yield a half-maximal inhibitory concentration value, IC50, as the cell viability was above 50% at all concentrations. Cell viability over 90% was observed at the concentrations of 3.125 and 1.5625 mg/ml. Maximum concentration of the material showed cell viability of 59.4%. CONCLUSIONS: This new fast set highly viscous conventional GIC showed low cytotoxicity to mouse fibroblast cells, and it can be suggested as a substitute for dental cements exhibiting a long setting time.

Significant association of high-risk human papillomavirus (HPV) but not of p53 polymorphisms with oral squamous cell carcinomas in Malaysia.

PURPOSE: The purpose of this study was to evaluate the role of HPV and p53 polymorphisms in oral squamous cell carcinomas (OSCC) affecting Malaysian population. METHODS: We analysed frozen samples from 105 OSCC as well as 105 oral specimens derived from healthy individuals. PCR assays targeting two regions of the virus were used. PCR amplification for the analysis of p53 codon 72 arginine/proline alleles was carried out in a separate reaction. RESULTS: HPV DNA was detected in 51.4% OSCC samples, while 24.8% controls were found to be HPV positive. HPV was found to be significantly associated with OSCC (P < 0.001, OR = 4.3 after adjustment for habits) when compared to controls. High-risk HPV was found to be significantly associated with OSCC cases (P < 0.05). Demographic profiles of age, gender, race and habits were not associated with HPV presence in cases and controls. However, significantly less HPV positivity was seen in poorly differentiated compared to well-differentiated OSCCs. No significant association was found between HPV positivity and p53 polymorphisms in cases and control groups. Additionally, we found no association of codon 72 polymorphism with oral cancer. CONCLUSIONS: This study indicates that high-risk HPV infection is one of the contributing factors for OSCCs. HPV 16 was the predominant type found in Malaysian patients with OSCC. Further, we did not find any association between p53 codon 72 polymorphism and HPV infection or between the p53 polymorphism and the risk of oral cancer.

Association of human papillomavirus with denture wearing.

AIM: To determine the prevalence of human papillomavirus in the oral cavity of denture wearers. METHODS: Swabs were collected from 72 denture wearers and 72 controls (non-denture wearers) to obtain DNA. Amplification of the ß-globin gene was performed by polymerase chain reaction to check the integrity of extracted DNA. The presence of human papillomavirus in the DNA sample was detected by nested polymerase chain reaction. RESULTS: The prevalence of human papillomavirus was found to be significantly higher in the oral cavity of denture wearers (38/72, 52.8%) than in the controls (17/72, 23.6%; odds ratio = 3.612, confidence interval = 1.771/7.385, P = <0.001). When adjusted for variables, including age, sex, ethnicity, and smoking habit, human papillomavirus was still found to be significantly associated with denture wearing, with an adjusted odds of 3.2 (P = 0.008). No association of human papillomavirus positivity was found with denture variables, including denture type, denture material type, duration of denture wearing, and denture hygiene (P > 0.05). Low-risk human papillomavirus types were found to be more frequent in both groups. CONCLUSIONS: The prevalence of human papillomavirus in the oral cavity of denture wearers was found to be significantly higher compared to controls; however, it was mainly low-risk types.

Antiproliferative effect of Tualang honey on oral squamous cell carcinoma and osteosarcoma cell lines.

BACKGROUND: The treatment of oral squamous cell carcinomas (OSCC) and human osteosarcoma (HOS) includes surgery and/or radiotherapy which often lead to reduced quality of life. This study was aimed to study the antiproliferative activity of local honey (Tualang) on OSCC and HOS cell lines. METHODS: Several concentrations of Tualang honey (1% - 20%) were applied on OSCC and HOS cell lines for 3, 6, 12, 24, 48 and 72 hours. Morphological characteristics were observed under light and fluorescent microscope. Cell viability was assessed using MTT assay and the optical density for absorbance values in each experiment was measured at 570 nm by an ELISA reader. Detection of cellular apoptosis was done using the Annexin V-FITC Apoptosis Detection Kit. RESULTS: Morphological appearance showed apoptotic cellular changes like becoming rounded, reduction in cell number, blebbed membrane and apoptotic nuclear changes like nuclear shrinkage, chromatin condensation and fragmented nucleus on OSCC and HOS cell lines. Cell viability assay showed a time and dose-dependent inhibitory effect of honey on both cell lines. The 50% inhibitory concentration (IC50) for OSCC and HOS cell lines was found to be 4% and 3.5% respectively. The maximum inhibition of cell growth of ≥80% was obtained at 15% for both cell lines. Early apoptosis was evident by flow cytometry where percentage of early apoptotic cells increased in dose and time dependent manner. CONCLUSION: Tualang honey showed antiproliferative effect on OSCC and HOS cell lines by inducing early apoptosis.

High-risk human papillomavirus in the oral cavity of women with cervical cancer, and their children.

BACKGROUND: Association of High-risk Human Papillomavirus (HR-HPV) with oral cancer has been established recently. Detecting these viruses in oral cavity is important to prevent oral lesions related to them. The purpose of this study was to evaluate the prevalence of HR-HPV in the oral cavity of women with cervical cancer, and their children. A total of 70 women, previously diagnosed with cervical cancer, and 46 children of these women, born by vaginal delivery only, were selected for this study. Buccal swabs were collected from their oral cavity and HPV detection was carried out using Hybrid Capture 2 high-risk HPV (HC2 HR-HPV) detection system. RESULTS: Out of 70 women with cervical cancer, four (5.71%) were found to be positive for HR-HPV in their oral cavity. No association of HR-HPV was found with sociodemographic profile, marital status, reproductive history, tobacco and alcohol usage, contraceptive pills usage, and presence of oral lesions (p>0.05). Among children, HR-HPV in the oral cavity was detected in only 1 of the 46 subjects examined (2.17%). Clinically healthy oral mucosa, without any oral lesions, was observed in all the HR-HPV positive subjects. CONCLUSION: The result of this study showed that there is low, if any, risk of HR-HPV infection in the oral cavity of women with cervical cancer. Further, our study suggests that there is very low risk for children of women with cervical cancer, to acquire and sustain HR-HPV in their oral cavity until childhood or adolescence.

Oral mucosal lesions in non oral habit diabetic patients and association of diabetes mellitus with oral precancerous lesions.

AIMS: This study was aimed to determine the prevalence of oral mucosal lesions (OML) in patients with diabetes mellitus (DM) and non-diabetic subjects without any oral habits and to investigate the association of DM with oral precancerous lesions. METHODS: This cross-sectional study involved 420 diabetic and 420 non-diabetic control subjects without any oral habits. Detailed oral examination was performed based on international criteria. RESULTS: A significantly greater proportion of subjects with DM (45%) had one or more OML in comparison to non-diabetics (38.3%). Patients with DM showed a significantly greater prevalence of geographic tongue, denture stomatitis and angular cheilitis than non-diabetics (p<0.05). The results also showed an association between occurrence of one or more OML and metabolic control of diabetic patients (p<0.05). For precancerous lesions, lichen planus was found in two diabetic patients while none of controls had any precancerous lesion (p>0.05). CONCLUSIONS: Prevalence of OML was significantly higher in diabetic patients than non-diabetics and this prevalence was associated with the metabolic control of the patients. However, no association was observed between DM and oral precancerous lesions.

Fibroblastic variant of osteosarcoma: a challenge in diagnosis & management.

Osteosarcoma of the jaws is a relative rare malignant bone tumor. Like, its counterpart in the long bones, osteosarcoma affecting the head and neck region shows distinct yet diverse clinical, histologic and prognostic characteristics. Its diagnosis is a challenge to histopathologists and is especially important in early stages to improve its prognosis. In the initial phase, it may present as nondescript swelling with an indolent growth rate, only to become overtly aggressive and malignant towards the later phase of the disease. This article reports on a case of an advanced osteosarcoma of the maxilla in a 42 year old woman who came for the evaluation of a swelling. The case was submitted for surgical intervention and was followed by one recurrence till the time of reporting. This case illustrates that immunohistochemical staining of Vimentin, S-100 and CD 68 markers are useful to confirm the histologic diagnosis of osteosarcoma, along with radiographic evaluation using CT scan and 3D imaging.

Single-tube seminested PCR assay for detecting human papillomavirus in clinical samples.

There is a growing appreciation of the potential value for routine screening for the presence of HPV not only for cervical specimens but also from oral cavity. The purpose of this study was to develop and clinically evaluate a single-tube seminested PCR assay for the detection of HPV. Several parameters such as PCR primers, primer annealing temperature, the number of PCR cycles and concentration of PCR components were optimized. The assay was evaluated using HPV inserts of type 6, 11, 16, 18, 31, 33, 38 and 51. Evaluation of seminested PCR assay was performed with cervical scrapings from 30 patients and buccal swabs from 30 head and neck cancer patients and results were compared with those of two-tube nested PCR. The results were found to be comparable with a total of 60% (36/60) of samples being positive for HPV using the single-tube assay, while 62% (37/60) positivity was found with two-tube PCR assay. We succeeded in developing a single-tube seminested PCR method for HPV DNA detection which is easier than the conventional nested PCR and can be further evaluated as a potential screening tool for detecting HPV in oral and cervical regions.

Chondrosarcoma of the mandible: a case report.

Chondrosarcomas are malignant tumours of cartilaginous origin. They range from a well-differentiated growth resembling a benign cartilage tumour to a high-grade malignancy with aggressive local behaviour and the potential to metastasize. Only 5% to 10% of chondrosarcomas are known to occur in the head and neck region. A case of chondrosarcoma of the anterior region of the mandible is presented, along with a review of the relevant literature.

The awareness of oral cancer in adult patients attending School of Dental Sciences, Universiti Sains Malaysia: a preliminary study.

OBJECTIVE: Lack of awareness of signs and symptoms and risk factors of oral cancer can lead to late presentation of the disease that contributes to poor survival of patients who contract it. This study aims to determine the level of awareness regarding oral cancer in adult patients attending School of Dental Sciences, Universiti Sains Malaysia. MATERIALS AND METHODS: This was a cross-sectional study in which face-to-face interview of 108 subjects aged 20-65 was conducted. The questionnaire consisted of personnel details and questions regarding awareness of risk factors, complications, signs and symptoms, and prevention of oral cancer. Each response was assigned scores where one (1) mark was given for a correct answer and one (1) mark was subtracted for every wrong answer. The scores were added up to obtain total individual score. RESULTS: Majority of the patients interviewed were from the age range of 20-29. Most of the respondents were Malays with females having a higher percentage (52.8%) than males (47.2%). Majority of the patients (89.9%) were aware regarding the presence of the oral cancer. However, there was no significant association of age range and gender (p > 0.05). 96.7% of subjects who have had higher education were significantly more aware about the presence of oral cancer when compared to those without any schooling (p < 0.05). There was a high awareness of the link between smoking, tobacco chewing, betel nut chewing, and alcohol (93.5%, 85.2%, 75.9%, and 68.5%, respectively) with oral cancer. Almost three-fourth (73%) scored between 10 and 19 out of the maximum of 23 with the mean score of 13.4 (standard deviation, 4.37). All our subjects agreed that early detection of oral cancer could improve chances of successfully treating them. CONCLUSION: There was a moderate level of awareness regarding oral cancer towards its risk factors, complications, signs and symptoms, and prevention of oral cancer.