Formalin Induced Micronucleus Formation in the Buccal Mucosa of Pathology Laboratory Workers.

Background & Objective: Formaldehyde is an irritating substance that is categorized as a definite carcinogen (Group A1), according to the International Agency for Research on Cancer (IARC). This study was conducted to determine the role of this substance in the frequency of micronuclei (MN) in the buccal mucosal cells due to long-term exposure of the pathology staff to formaldehyde. Methods: In this case-control study, 32 pathology laboratory staff members were assigned to the case group, and 32 staff members who were not exposed to formaldehyde were assigned to the control group. Buccal mucosa cells were collected with a wet spatula and stained with Papanicolaou stain. In each sample, 500 cells were counted; then, the frequency of MN and the average number of MN in the micronucleated cells were assessed and compared between the 2 groups using the independent t test. Furthermore, the relationship between gender and MN was evaluated using the independent t test. The relationship between years of exposure and time of exposure during the day (in hours) for the case group, as well as the relationship between age and frequency of MN was analyzed using the Pearson correlation coefficient. Results: The mean frequency of MN in exfoliated buccal cells was 18.33±12.36 in the case group, which was significantly higher than the control group (10.55±6.22; P=0.003). The difference in the mean number of total MN in the micronucleated cells was not significant between the case and control groups (P=0.11). The relationship between sex, age, and years of exposure with the mean frequency of MN and the total number of MN in the micronucleated cells was not significant. The relationship between exposure time during the day and both the mean frequency of MN and the total number of MN in the micronucleated cells was significant (P=0.03). Conclusion: Formaldehyde exposure and extended time of exposure during the day can increase the frequency of MN, which can prognosticate the incidence of precancerous and cancerous lesions. Therefore, continuous exposure to formaldehyde can be considered an occupational health hazard, though further studies are needed to confirm this result.

Micronucleus assay in the exfoliated cells of buccal mucosa of gasoline station workers in Tehran.

Objectives: One of the most critical landmarks of DNA damage is the micronucleus assay. Enumeration of micronuclei contributes to the early diagnosis of precancerous lesions and cancers; however, there are few studies on the frequency of micronucleus in gasoline station workers. To the best of our knowledge, no study has addressed this issue in Iran. The present study aimed to determine the role of working in the gasoline stations of Tehran city on micronucleus frequency in buccal mucosa. Materials and Methods: In this historical cohort study, buccal mucosa samples were collected from 110 individuals working at gasoline stations and 100 unemployed persons using wet tongue depressors. After Papanicolaou staining, the percentage of cells containing micronucleus as well as the mean number of micronucleus in the micronucleated cells was reported. Student's t-test, Mann-Whitney test, and regression analyses were used to specify the effect of other variables on the frequency and mean number of micronucleus per cell. Results: The mean frequency of micronucleus in the case and control group was 29.8 ± 8.2 and 9.3 ± 3.2, respectively, which was statistically significant (P = 0.0001). Furthermore, the mean number of micronucleus in the micronucleated cells of buccal mucosa was significantly higher in individuals who were exposed to gasoline than the control group (P = 0.0001). Conclusion: The results indicated that exposure to gasoline could increase the frequency of micronucleus. It was also revealed that cigarette and hookah smoking and alcohol consumption, together with working in gasoline stations, increase micronucleus abundance, implying the cumulative carcinogenic effect of these factors.

The ability of orexin-A to modify pain-induced cyclooxygenase-2 and brain-derived neurotrophic factor expression is associated with its ability to inhibit capsaicin-induced pulpal nociception in rats.

Background: The rostral ventromedial medulla (RVM) is a critical region for the management of nociception. The RVM is also involved in learning and memory processes due to its relationship with the hippocampus. The purpose of the present study was to investigate the molecular mechanisms behind orexin-A signaling in the RVM and hippocampus's effects on capsaicin-induced pulpal nociception and cognitive impairments in rats. Methods: Capsaicin (100 g) was applied intradentally to male Wistar rats to induce inflammatory pulpal nociception. Orexin-A and an orexin-1 receptor antagonist (SB-334867) were then microinjected into the RVM. Immunoblotting and immunofluorescence staining were used to check the levels of cyclooxygenase-2 (COX-2) and brain-derived neurotrophic factor (BDNF) in the RVM and hippocampus. Results: Interdental capsaicin treatment resulted in nociceptive responses as well as a reduction in spatial learning and memory. Additionally, it resulted in decreased BDNF and increased COX-2 expression levels. Orexin-A administration (50 pmol/1 µL/rat) could reverse such molecular changes. SB-334867 microinjection (80 nM/1 µL/rat) suppressed orexin's effects. Conclusions: Orexin-A signaling in the RVM and hippocampus modulates capsaicininduced pulpal nociception in male rats by increasing BDNF expression and decreasing COX-2 expression.

The rostral ventromedial medulla orexin 1 receptors and extracellular signal-regulated kinase in hippocampus are involved in modulation of anxiety behavior induced by dental pulp nociception in adult male rats.

OBJECTIVES: To explore the role of rostral ventromedial medulla (RVM) orexin 1 receptors (OX1R) on orofacial nociception -induced anxiety and locomotion in rats. DESIGN: Forty two adult male Wistar rats (220-270 gr) were randomly divided into 7 groups (n = 6) as follows: untreated control, capsaicin, capsaicin vehicle-treated group (sham operation), capsaicin groups pretreated by intra-RVM administration orexin 1 receptor (OX1R) agonist (orexin A) or antagonist (SB-334867) and the capsaicin groups treated by drugs vehicles (DMSO or aCSF). Orofacial nociception was induced by intradental application of capsaicin (100 µg) into the incisors of rats. Anxiety level and locomotor activity were measured by the elevated plus maze (EPM) and open field (OF) tests, respectively. Hippocampal levels of phosphorylated extracellular signal regulated Kinase (p-ERK) was also assessed by western blotting. RESULTS: Intradental application of capsaicin significantly increased anxiety and decreased locomotion behaviors. Intra-RVM microinjection of orexin-A significantly prevented capsaicin-induced anxiety-like behavior and increased locomotor activity in the EPM and OF tests. These effects were inhibited by SB-334867. Furthermore, orexin-A significantly increased p-ERK levels in capsaicin-treated rats. This effect was inhibited by pretreatment of the rats with SB-334867. CONCLUSIONS: The results suggest that both OX1R signaling in the RVM and hippocampal p-ERK signaling are involved in orofacial nociception-induced anxiety as well as locomotor activity.

Selective anticancer activity of superparamagnetic iron oxide nanoparticles (SPIONs) against oral tongue cancer using in vitro methods: The key role of oxidative stress on cancerous mitochondria.

Today, it has been proven that the nanoparticles such as superparamagnetic iron oxide nanoparticles (SPIONs) have widespread use in biomedical applications, for instance, in magnetic resonance imaging and targeted delivery of drugs. Despite many studies on SPIONs in diagnosing some diseases like cancer, it has not been investigated on the oral tongue squamous cell carcinoma (OTSCC) detection by the NPs. Hence, the present study has been designed to assess the in vitro cytotoxicity of SPIONs on the isolated mitochondria of OTSCC by mitochondrial tests. Isolated mitochondria were removed from the separated cancer and control tissues from the squamous cells of tango in male Wistar rats (6 or 8 weeks) and exposed to the different concentrations of SPIONs (30, 60, and 120 nM). A rise in the production of reactive oxygen species is one of the significant mechanisms of this study, followed by a collapse of mitochondrial membrane potential, the escape of mitochondrial cytochrome c, and mitochondrial swelling in the exposed isolated mitochondria of OTSCC with SPIONs. Furthermore, our results indicated that the exposure to the SPIONs reduced the activity of succinate dehydrogenase in complex II of the mitochondria obtained from cancerous oral tongue squamous. So the SPIONs can induce selective cytotoxicity on the OTSCC mitochondria without significant effects on the control mitochondria. Based on the results and further studies about in vivo experiments in this regard, it is concluded the SPIONs may be a hopeful therapeutic candidate for the treatment of OTSCC.

Expression of epidermal growth factor receptor in oral and esophageal squamous-cell carcinoma.

BACKGROUND: Squamous-cell carcinoma (SCC) represents the most common type of malignancies in the oral cavity (O) and esophagus (E). Epidermal growth factor receptor (EGFR) plays a key role in numerous processes that affects tumor growth, progression, differentiation, invasion, metastasis, and inhibition of apoptosis. In this study, we wanted to investigate the EGFR expression in OSCC and ESCC cases. As well, another purpose was to observe if there exists any relation between its expression and clinicopathologic factors. To the best of our knowledge, this is the first study which compares the EGFR protein expression between OSCC and ESCC. MATERIALS AND METHODS: This cross-sectional study was performed on 46 paraffin blocks (23 OSCC and 23 ESCC). The expression of EGFR was evaluated with immunohistochemical technique. Data analyses were done using SPSS software by Fisher's exact test. Significance was assigned at P < 0.05. RESULTS: Out of 46 patients, 25 cases (54.3%) were male and 21 (45.7%) were female. Seventy-eight percent of OSCCs and 73.9% of ESCCs showed high expression of EGFR. No statistically significant difference was observed between the two groups (P = 0.73). There were no statistically significant correlations between EGFR expression and clinicopathologic factors (age, gender, grade, and stage) of OSCCs (P > 0.05). A statistically significant correlation was found between EGFR expression and stage in ESCCs group (P = 0.006). CONCLUSION: No significant correlation was found between the expression of EGFR protein in OSCCs and ESCCs. High expression of EGFR was observed in ESCCs with Stages II, III.

GABAB receptor activation ameliorates spatial memory impairments in stress-exposed rats.

Objective: Due to the prevalence of stress in modern life and its impact on spatial memory, the role of inhibitory systems in brain areas such as the nucleus accumbens (NAc) in reducing stress is important. The current study aimed to examine the response of NAc shell GABAB receptors to stress and the role of intraperitoneally (i.p.) and intra-NAc injection of the GABAB receptor agonist baclofen on spatial memory impairments in stress-exposed rats. Methods: Eighty adult male Wistar rats were randomly divided into ten groups (n=8): two were control groups for intra-NAc and i.p baclofen; two groups were subjected to stress and injected with saline (baclofen vehicle); three groups were given baclofen (1, 5, and 10 µg/rat) intra-NAc 5 mins before stress was induced; and three groups received baclofen (1, 5, and 10 mg/kg/i.p.) 30 mins before being subjected to stress. Foot-shock stress was applied for 7 consecutive days. Behavioral assays using the Barnes maze were performed 24 hrs after the last baclofen injection. Results: Both the intra-NAc and the i.p administration of baclofen dose-dependently reduced escape latency and total distance and increased velocity in the treatment groups in the training trials. In the probe test, the rats that had received 5 mg/kg of baclofen had the highest target frequency, but there no significant differences were observed in velocity, duration, or distance to the target between the groups. Conclusion: According to the findings, baclofen can dose-dependently improve spatial memory, and GABAB receptor in the NAc plays an important role in spatial memory.

Expression of CD34 and CD31 in Central and Peripheral Giant Cell Granulomas.

STATEMENT OF THE PROBLEM: There are some differences between clinical features of central giant cell granulomas (CGCGs) and peripheral giant cell granulomas (CGCGs) despite their same microscopic features. The possible role of angiogenesis in this issue is still a matter of debate. PURPOSE: The aim of the present study was to compare microvessel density (MVD) between CGCGs and PGCGs of the oral cavity using CD31 and CD34. MATERIALS AND METHOD: Immunohistochemical staining was performed on 18 PGCGs and 19 CGCGs using a monoclonal antibody against CD34 and CD31. MVD was assessed and compared between the lesions using t-test for statistical analysis. p< 0.05 was considered significant. RESULTS: The expression levels of both CD34 and CD31 were significantly higher in CGCGs compared to PGCGs (p< 0.002 and p< 0.001, respectively). Significant differences in MVD assessed by both markers were observed between males and females in PGCGs (p< 0.05), but not CGCGs (p< 0.2). CONCLUSION: The combined evaluation of old- and newly-formed vessels by pan-endothelial cell markers showed differences between CGCGs and PGCGs, supporting the possible vascular-proliferative nature of the former. Whether this difference has a part in their diverse biologic behaviors and the role which pre-existent vessels play in comparison to neo-formed vasculature, requires further investigation.

Angiogenesis concept in odontogenic keratocyst: A comparative study.

CONTEXT: Recent reports have indicated that angiogenesis possibly affects the biologic behavior of the lesions. AIM: Given the different clinical behaviors of odontogenic keratocyst (OKC), the present study was undertaken to evaluate the concept of angiogenesis in pathogenesis and clinical behavior of OKC. SETTING AND DESIGN: This experimental study was carried out on 22 and 24 samples of OKCs and dentigerous cysts (DCs), respectively. METHODS: Immunohistochemical staining was approached using CD34 and vascular endothelial growth factor (VEGF) antibodies. The expression of VEGF was first reported by determining the counts of stained cells, including epithelial cells, fibroblasts, and endothelial cells, followed by the percentage of stained cells in each sample based on a 0-2 scoring system. The counts of CD34+ cells were reported in each group in the form of means ± standard deviations. In addition, the patterns of blood vessels in the samples prepared from the walls of both cysts were evaluated. STATISTICAL ANALYSIS USED: Mann-Whitney U-test, Chi-squared test, and t-test were used for analysis of data, and statistical significance was defined at p < 0.05. RESULTS: The expression percentage and scores of VEGF and the mean expression rate of CD34 were significantly higher in OKCs than DCs (p = 0.045, 0.000, and p = 0.58). Finally, there was a strong correlation between the expressions of the two markers in the samples (Correlation coefficient = 0.766). CONCLUSION: The present results indicate the angiogenesis may play an important role in the pathogenesis and the unique clinical behavior of OKC.

The Possible Role of Mast Cells in the Odontogenic Cyst's Pathogenesis: A Comparative Study between Dentigerous Cyst and Keratocystic Odontogenic Tumor.

Background. Recently, mast cells were recognized in the pathogenesis of more aggressive pathologic lesions. This study was aimed to evaluate and compare the density of mast cells in Dentigerous cyst (DC) and Keratocystic odontogenic tumor (KCOT) regarding their different clinical behavior. Method. This study was conducted on 23 and 26 cases of DC and KCOT, respectively. Four-micron sections were prepared for Toluidine blue staining and mast cell densities in two desired cysts were studied. Final data was analyzed via t-test and Mann-Whitney U test method regarding the significant level lower than 0.05. Results. Mast cell densities were significantly higher in KCOTs for deep and superficial layers and both layers (P < 0.05). The density of degranulated mast cells in the deeper layers and both layers was significantly higher in KCOTs (P < 0.05). However, the density of degranulated mast cells in the superficial layer had no significant difference (P > 0.05). Conclusion. It seems that mast cells may be involved in the pathogenesis of KCOT, but, regarding wide range of mast cell's biologic activities, further investigations are recommended to confirm the issue and prepare the details.

Mast Cell Concentrations in Peripheral and Central Giant Cell Granulomas: Is there any Angiogenetic Role?

BACKGROUND: In the maxillofacial region, giant cell granulomas occur in 2 clinical forms, central and peripheral. Despite histopathological similarity between these 2 forms totally different clinical behaviors have been reported. The present study was undertaken to compare mast cell and vascular concentrations in these pathologic lesions. MATERIALS AND METHODS: In this cross-sectional descriptive study, 20 pathological samples of central giant cell granuloma (CGCG) and 20 samples of peripheral giant cell granuloma (PGCG) were selected and examined through toluidine blue staining for mast cell assessment and immunohistochemical staining by VEGEF antibody for comparing the number of mast cells. T-test, chi-squared test and backward multivariate linear regression were used for statistical analysis using SPSS 20. Statistical significance was set at P<0.05. RESULTS: This study showed significantly greater VEGF expression and mast cell concentrations in CGCG compared to PGCG cases. Also there was a significant correlation between VEGF expression and the concentration of mast cells. No relation was found between age, sex and site of the lesion and concentration of mast cells or VEGF expression. CONCLUSIONS: It is feasible that higher concentrations of mast cells in CGCG versus PGCG samples might lead to more aggressive clinical behavior via vascular proliferation and angiogenesis. However, other biologic mechanisms should be considered in this situation.

Evaluation of Microvascularity by CD34 Expression in Esophagus and Oral Squamous Cell Carcinoma.

AIM: The present study was scheduled to evaluate microvascularity by CD34 expression in esophagus and oral squamous cell carcinoma. MATERIALS AND METHODS: This study was scheduled using 40 paraffin blocked samples including 20 of oral SCC and 20 of esophagus ones and Immunohistochemical staining was conducted using CD34 monoclonal antibody. Exact fisher test was used to evaluate frequency of expression between two studied groups. RESULTS: There was significant correlation between age and tumor size with CD34 expression in oral SCC samples (p < 0.05) and no significant correlation between sex and tumor differentiation level (grading) (p > 0.05). Also, there was no significant correlation between age, sex, tumor size and tumor differentiation level (grading) with CD34 expression in esophagus SCC samples (p > 0.05). There was no significant difference of CD34 expression frequency in oral and esophagus SCC (p = 0/583). Finally, CD34 expression was reported 'high' for major cases of esophagus and oral SCCs. CONCLUSION: It seems, other angiogenetic or nonangiogenetic factors except CD34 may play more important role and explain the different clinical behavior of SCC at recent different locations. CLINICAL SIGNIFICANCE: Other factors would be considered along with CD34 expression to interpret different clinical behavior of SCC at recent different locations.

Increased Salivary Nitrite and Nitrate Excretion in Rats with Cirrhosis.

Increased nitric oxide (NO) formation is mechanistically linked to pathophysiology of the extrahepatic complications of cirrhosis. NO is formed by either enzymatic or non-enzymatic pathways. Enzymatic production is catalyzed by NO synthase (NOS) while entero-salivary circulation of nitrate and nitrite is linked to non-enzymatic formation of NO under acidic pH in the stomach. There is no data on salivary excretion of nitrate and nitrite in cirrhosis. This study was aimed to investigate salivary levels of nitrate and nitrite in a rat model of biliary cirrhosis. Cirrhosis was induced by bile duct ligation (BDL). Four weeks after the operation, submandibular ducts of anesthetized BDL and control rats were cannulated with polyethylene microtube for saliva collection. Assessment of pH, nitrite and nitrate levels was performed in our research. We also investigated NOS expression by real time RT-PCR to estimate eNOS, nNOS and iNOS mRNA levels in the submandibular glands. Salivary pH was significantly lower in BDL rats in comparison to control animals. We also observed a statistically significant increase in salivary levels of nitrite as well as nitrate in BDL rats while there was no elevation in the mRNA expression of nNOS, eNOS, and iNOS in submandibular glands of cirrhotic groups. This indicates that an increased salivary level of nitrite/nitrate is less likely to be linked to increased enzymatic production of NO in the salivary epithelium. It appears that nitrate/nitrite can be transported from the blood stream by submandibular glands and excreted into saliva as entero-salivary circulation, and this mechanism may have been exaggerated during cirrhosis.

Effect of lithium on secretory factors and growth stimulation by bombesin in rat pancreas and salivary glands.

Lithium, a drug of choice in bipolar affective disorders, also affects the metabolism and cell proliferation in a diverse array of organisms. In this study, we investigated the effect of lithium on bombesin-mediated function in excretion and growth of the pancreas and the salivary glands. The weight, protein content, amylase concentration and salivary flow rate of the pancreas, parotid and the submandibular glands were determined in male Wistar rats after consumption of either water or lithium chloride (600 mg/l) for 14 days and each group received s.c. injection of either saline or bombesin (10 microg/kg) during the last 4 days of experiment. Our results revealed that administration of bombesin in lithium-treated group not only suppressed pancreas and parotid weight augmentation due to bombesin, but also significantly decreased pancreas growth. Chronic lithium consumption significantly inhibited the protein content augmentation due to bombesin in the salivary glands. Getting bombesin, as well as saline in lithium-treated group, resulted in notable decrease in salivary protein content. Protein content of pancreatic gland increased considerably in the bombesin-injected groups either treated with saline or lithium. In conclusion, the stimulatory effect of bombesin on the growth and protein content of the pancreas and the salivary gland was inhibited by lithium. Lithium seems to be a potent inhibitor of growth factors induced by bombesin probably through inhibiting phosphatidylinositol 4,5,bisphosphate hydrolysis.

Immunohistochemical evaluation of p27 (kip1) in pleomorphic adenomas and adenoid cystic carcinomas of the minor salivary glands.

BACKGROUND: p27(kip1), a universal cyclin-dependent kinase inhibitor, is a useful marker for predicting clinical aggressiveness with various human tumors. In this study, p27 expression was investigated in pleomorphic adenomas (PAs) and adenoid cystic carcinomas (ACCs) of minor salivary glands to evaluate its utility for differentiation purposes. At the same time, the correlation between p27 and ACC grading was evaluated. MATERIALS AND METHODS: Clinicopathological features of 22 patients (11 ACCs, 11 PAs), including age, sex and size of tumor were obtained from medical records. Immunohistochemical staining with p27(kip1) was performed for each specimen and p27 labelling indices were determined with a computer-assisted image-analyzing system (CAS 200). Pearson's correlation coefficient, Spearman's correlation coefficient, Students t-test, Kruskal-Wallis test and ANOVA were applied for statistical analyses using SPSS 11.5. RESULTS: p27 LIs for all PAs were above 25% whereas for ACCs they were under 25% (except one case). p27 expression (LI and intensity) was significantly lower in ACCs than PAs. The correlation between p27 expression and ACC grading was not significant. CONCLUSION: Overall, these findings suggest that reduced expression of p27 might be correlated with the development of ACC and could be an indicator of malignant behavior.