Genetic diversity of Mycobacterium tuberculosis isolates from northwest of Iran during COVID-19 era.

Background: Tuberculosis (TB) is considered one of the most infectious diseases in the world. In this study, we intended to examine the epidemiology of tuberculosis by MIRU-VNTR to define the changes that occur in the transmission of tuberculosis in the region during the COVID-19 era. A total of 120 Mycobacterium tuberculosis isolates were collected from sputum samples of patients referred to East Azerbaijan Center TB from December 2020 to August 2021. Demographic information such as age, sex, place of birth, previous TB history, and relevant medical data was collected. The proportion method was performed for drug susceptibility testing, and the PCR-based MIRU-VNTR method was applied to identify molecular epidemiology relationships. Results: The isolates were collected from 78 male (65%) and 39 female (32.5%) Iranian patients and 3 (2.5%) Azerbaijani patients. Ninety-three distinct patterns were identified including 15 clustered patterns and 36 unique patterns. The largest cluster was composed of seven isolates. Furthermore, one cluster with 5 members, four clusters with 3 members, and nine clusters with 2 members. In MIRU-VNTR typing, 75 clusters belonged to the Tabriz region and just 3 to the Republic of Azerbaijan. All isolates were sensitive to rifampin, isoniazid, and ethambutol. Conclusions: Results of the current study showed COVID-19 pandemic had a direct effect on the transmission and diagnosis of tuberculosis. Less diagnosis and less clustering can indicate public controls and hygiene, and the use of masks had a direct effect on the transmission and diagnosis of tuberculosis. However, misidentification and less focus on other respiratory infections are expected during the pandemic. Studies on the co-infection of COVID-19 and tuberculosis and the role of mask and sanitization against TB are strongly recommended.

Bacteriocins: Recent Advances in its Application as an Antimicrobial Alternative.

Due to the emergence and development of antibiotic resistance in the treatment of bacterial infections, efforts to discover new antimicrobial agents have increased. One of these antimicrobial agents is a compound produced by a large number of bacteria called bacteriocin. Bacteriocins are small ribosomal polypeptides that can exert their antibacterial effects against bacteria close to their producer strain or even non-closely-relatedstrains. Adequate knowledge of the structure and functional mechanisms of bacteriocins and their spectrum of activity, as well as knowledge of the mechanisms of possible resistance to these compounds, will lead to further development of their use as an alternative to antibiotics. Furthermore, most bacteria that live in the gastrointestinal tract (GIT) have the ability to produce bacteriocins, which spread throughout the GIT. Despite antimicrobial studies in vitro, our knowledge of bacteriocins in the GIT and the migration of these bacteriocins from the epithelial barrier is low. Hence, in this study, we reviewed general information about bacteriocins, such as classification, mechanism of action and resistance, emphasizing their presence, stability, and spectrum of activity in the GIT.

MALDI-TOF Mass Spectroscopy Applications in Clinical Microbiology.

There is a range of proteomics methods to spot and analyze bacterial protein contents such as liquid chromatography-mass spectrometry (LC-MS), two-dimensional gel electrophoresis, and matrix-assisted laser desorption/ionization mass spectrometry (MALDI-TOF MS), which give comprehensive information about the microorganisms that may be helpful within the diagnosis and coverings of infections. Microorganism identification by mass spectrometry is predicted on identifying a characteristic spectrum of every species so matched with an outsized database within the instrument. MALDI-TOF MS is one of the diagnostic methods, which is a straightforward, quick, and precise technique, and is employed in microbial diagnostic laboratories these days and may replace other diagnostic methods. This method identifies various microorganisms such as bacteria, fungi, parasites, and viruses, which supply comprehensive information. One of the MALDI-TOF MS's crucial applications is bacteriology, which helps identify bacterial species, identify toxins, and study bacterial antibiotic resistance. By knowing these cases, we will act more effectively against bacterial infections.

Chitosan biomaterials application in dentistry.

Chitosan is a natural biopolymer derived from deacetylation of chitin and it has been investigated with interdisciplinary approaches for multitude applications. Chitosan biomaterials possess unique properties such as biocompatibility, biodegradability, non-toxicity, muco-adhesion and a wide range of antibacterial and antifungal activity. Additionally, chitosan is the only cationic polysaccharide in nature and can be chemically modified to derivatives, based on the aim of function and application. The distinctive properties of chitosan and its derivatives have aroused interest in pharmaceutical industries and biomedical fields worldwide. This review discusses the crucial role of chitosan in production of bio-dental materials and accentuates its current profitable utilizations in oral drug delivery system, bone tissue engineering for treatment of periodontitis and dentin-pulp regeneration. Chemical modifications and incorporation of diverse bioactive molecules in order to improve the mechanical and biological characteristics of chitosan have also been discussed.

Chitin/silk fibroin/TiO2 bio-nanocomposite as a biocompatible wound dressing bandage with strong antimicrobial activity.

Interconnected microporous biodegradable and biocompatible chitin/silk fibroin/TiO2 nanocomposite wound dressing with high antibacterial, blood clotting and mechanical strength properties were synthesized using freeze-drying method. The prepared nanocomposite dressings were characterized using SEM, FTIR, and XRD analysis. The prepared nanocomposite dressings showed high porosity above 90% with well-defined interconnected porous construction. Swelling and water uptake of the dressing were 93%, which is great for wound dressing applications. Haemostatic potential of the prepared dressings was studied and the results proved the higher blood clotting ability of the nanocomposites compared to pure components and commercially available products. Besides, cell viability, attachment and proliferation by MTT assay and DAPI staining on HFFF2 cell as a Human Caucasian Foetal Foreskin Fibroblast proved the cytocompatibility nature of the nanocomposite scaffolds with well improved proliferation and cell attachment. To determine the antimicrobial efficiencies, both disc diffusion method and colony counts were performed and results imply that nanocomposite scaffolds have high antimicrobial activity and could successfully inhibit the growth of E. coli, S. aureus, and C. albicans. Moreover, based on these results, the prepared chitin/silk fibroin/TiO2 nanocomposite dressing could serve as a kind of promising wound dressing with great antibacterial and antifungal properties.

Comparison of Salivary Bacterial Flora in Iranian Patients with Hiatal Hernia and Healthy Subjects

Objective: To evaluate salivary microbial flora of patients with hiatal hernia and compare it with that of healthy subjects. Material and Methods: In this cross-sectional study, 50 patients with hiatal hernia measuring >1 cm and 50 healthy subjects (as the controls) were selected using simple random technique. One mL of salivary sample was taken from each patient, transferred into 50-mL Falcon tubes and immediately carried to the microbiology Laboratory of Tabriz Faculty of Medicine. The salivary samples were cultured on specific Streptococcus viridans (S. mitis, S. mutans, S. salivarius and S. sanguis), Enterococcus spp. and Lactobacillus culture media. Then the samples were incubated at 37°C for 7 days, followed by evaluation of the bacterial colonies. Statistical significance was defined at p<0.05. Results: A total of 34% of subjects with hiatal hernia and 26% healthy subjects exhibited Lactobacillus gasseri in their salivary samples; 16% of subjects with hernia and 6% of healthy subjects exhibited Enterococci spp. in their salivary samples. In addition, 82% of subjects with hernia and 72% of healthy subjects exhibited S. mutans in their salivary samples; 74% and 4% of subjects with hernia and 76% and 4% of healthy subjects exhibited gram-positive and gram-negative bacilli in their salivary samples, respectively. Furthermore, 98% of subjects with hernia and 86% of healthy subjects exhibited gram-positive cocci in their salivary samples, however without significant difference between the groups (p>0.05). Conclusion: No significant differences in the counts of Lactobacillus spp., Enterococcus spp., Streptococcus viridans and gram-positive and gram-negative bacterial species between healthy controls and subjects with hiatal hernia.

Comparison of microleakage and thickness of resin cement in ceramic inlays with various temperatures.

Background and aims. Microleakage is still one of the major problems of composite-based restorations.This study compared the microleakage and thickness of resin cement in ceramic inlays with various temperatures. Materials and methods. Class V cavities were prepared on the buccal and lingual aspects of thirty human molars with occlusal margins in enamel and gingival margins in dentin (3 mm wide, 5 mm long and 2 mm deep). Laboratory-made inlays (LMI) were used for buccal cavities, and CAD/CAM inlays (CMI) were used for lingual cavities. All the cavities were divided into six groups (n=10): 1) LMI at -5°C; 2) LMI at 50°C; 3) LMI at room temperature (25°C); 4) CMI at -5°C; 5) CMI at 50°C; 6) CMI at room temperature (25°C). Inlays were bonded to cavities in a pulp pressure- and temperature-simulating device. After thermocycling and dye penetration, the teeth were divided into two mesiodistal halves. Amount of dye penetration and film thickness were measured under a stereomicroscope and analyzed with Kruskal-Wallis, Wilcoxon and Spearman's correlation tests ( = 0.05). Results. There were no statistically significant differences in leakage between different inlay temperatures (P > 0.05). The mean cement thickness in laboratory-made inlays (gingival margin, 83.7 ± 11 and occlusal margin, 84.7 ± 19) was greater than that in CAD/CAM inlays (gingival margin, 69 ± 16 and occlusal margin, 84.7 ± 16). No correlation was found be-tween cement thickness and microleakage either in enamel or dentin for any of the ceramic systems. Conclusion. Differences in inlay temperature had no effect on microleakage. CAD/CAM inlays had lower cement thickness than laboratory-made inlays, but this was not related to their microleakage.

The effect of interleukin 36 gene therapy in the regression of tumor.

BACKGROUND: Cancer immunotherapy attempts to stimulate the immune system to reject and destroy tumors and is one of the cancer treatment strategies. Recently, interluekin36 (IL36) has been used as immunotherapeutic agents in cancer gene therapy. Present study investigated that the IL36 gene therapy effects on the regression of tumor masses in mouse model. Aim of this study is determination of the gene therapy effects by IL36 in the regression of tumor masses in mouse model. METHODS: To study the therapeutic efficacy of this cytokine, WEHI-164 tumor cells were transected with mIL36 plasmids. ELISA test was used to check cytokine production by transected cells. To establish fibro sarcoma mouse model, Tumoral transfected cells were injected subcutaneously to inoculate tumor in BALB/C mice. Tumor volumes were measured by caliper. Mice were sacrificed and tumors were extracted. The expression of IL36 and IFN-γ was studied with Real-time PCR and immunoblotting. The expression of Ki-67 (a tumor proliferation marker) in tumor masses was studied by immunohistochemistry staining. In this study we had 2 groups which are treated with IL-36 and Untreated with IL-36 as a blank. RESULTS: The group treated with IL36 indicated decrease of tumor mass volume (p<0.001). The results of western blotting and real-time PCR showed the IL36 expression increased in the group treated with IL36 (with relative expression of 1.9). CONCLUSION: Immunohistochemistry staining indicated that the Ki-67expression has been reduced in the group interfered with IL36. IL36 gene therapy has therapeutic effects on the regression of tumor masses in fibro sarcoma mouse model.

Serum Level of Interleukin 17 in Patients with Erosive and Non erosive Oral Lichen Planus.

BACKGROUND AND AIMS: Oral lichen planus is a relatively common chronic oral mucosal disease of unknown etiology. Regarding numerous studies on the immunologic factors involved in the etiology of lichen planus, the present study evaluated the serum interleukin-17 (IL-17) level in patients with erosive and non-erosive oral lichen planus. MATERIALS AND METHODS: This descriptive analytical study included 24 patients with erosive oral lichen planus (EOLP), 24 patients with non-erosive oral lichen planus (NEOLP) and 24 healthy volunteered as control. Blood samples of the subjects underwent ELISA, using special kits, to determine serum interleukin-17 levels. Data was analyzed using with descriptive statistic, chi-square test, and one-way ANOVA and Tukey post-hoc test with SPSS 16 software. RESULTS: EOLP patients showed a high level of serum IL-17 compared with NEOLP patents and control groups (EOLP=184.16 ± 12.41 pg/mL, NEOLP=106.09±10.78 pg/mL, control=15.50 ± 4.34 pg/mL, P - 0.001). CONCLUSION: High level of serum IL-17 in erosive oral lichen planus patients compared to the non-erosive type and healthy individuals may be the reason for higher inflammation and atrophy in the erosive type.

Elevated levels of interleukin-23 in sera of patients with pemphigus vulgaris.

BACKGROUND: Pemphigus vulgaris, a chronic mucocutaneous disease, is the most prevalent type of pemphigus which manifests with development of bullae and erosions on skin and mucosal membranes. OBJECTIVES: To investigate the potential role of IL-23 in pemphigus vulgaris. METHODS: In this study, 30 patients with pemphigus vulgaris and 30 healthy individuals were selected according to inclusion and exclusion criteria. Measurement of IL-23 serum levels in blood samples was conducted by ELISA. Data was analyzed using Student's t-test for comparison of IL-23 levels between the two groups. RESULTS: Mean serum levels of IL-23 in patients with pemphigus and healthy controls were 25.1 ± 4.2 and 17.9 ± 4.7 pg/ml, respectively (p<0.05). CONCLUSIONS: Based on the findings of this study, serum levels of IL-23 were higher in patients with pemphigus in comparison to healthy individuals with no clinical significance.

Effects of various mixing techniques on push-out bond strengths of white mineral trioxide aggregate.

INTRODUCTION: The aim of this study was to evaluate the effect of 3 different mixing methods on push-out bond strength of white tooth-colored mineral trioxide aggregate (MTA). METHODS: Sixty 2-mm-thick root sections were prepared from 60 single-rooted human teeth and filled with MTA. The samples were randomly divided into 3 groups (n = 20) of MTA mixed by ultrasonic, trituration, or conventional methods and then allowed to set for 72 hours in a synthetic tissue fluid environment. Push-out bond strength values of the specimens were measured by a universal testing machine and examined under a stereomicroscope at × 4 to determine the nature of the bond failure. RESULTS: The means of push-out bond strength values of white MTA in the ultrasonic, conventional, and trituration groups were 105.67 ± 12.79, 118.95 ± 12.76, and 99.60 ± 14.27 MPa, respectively. The differences between the 3 groups were not statistically significant. CONCLUSIONS: On the basis of the results of this study, it can be concluded that different mixing methods have no significant effect on push-out bond strength of white MTA.

Clinical evaluation of reasons for replacement of amalgam restorations in patients referring to a dental school in iran.

BACKGROUND AND AIMS: The present study evaluated the most common reasons for replacing amalgam restorations in a university clinic. MATERIALS AND METHODS: A total of 217 restorations which needed to be replaced were clinically and radiographically evaluated in a period of 4 months. The frequencies of reasons for replacing amalgam restorations were calculated: The assessed items included recurrent caries, tooth structure fracture (functional or non-functional cusps), amalgam bulk fracture, amalgam marginal fracture, proximal overhangs, and esthetics. Data were analyzed using Fischer's exact test. RESULTS: Both in vital teeth and teeth which had undergone root canal therapy, the most common reason for amalgam replacement was cusp fracture, with the fracture of non-functional cusps being statistically significant. Recurrent caries was the second most common reason for amalgam replacement. In Class I restorations, the most common reasons were recurrent caries and esthetics, with no statistical significance. The most frequent problem in Class II restorations was fracture of non-functional cusps, with a statistical significance in three-surface restorations. CONCLUSION: According to the results, failing to reduce undermined cusps and neglectful caries removal are the reasons for majority of amalgam restoration replacements. These issues should be emphasized in the curriculum for dental students and continuing education courses.

White sponge nevus: a case report.

White sponge nevus (WSN) is a rare hereditary dyskeratotic hyperplasia of mucous membranes. It is an autosomal dominant disorder with variable penetrance. We report a case of WSN in a healthy 21-year-old male with no history of familial involvement. A white smooth plaque with no erythema or other structural abnormalities was observed, which confirmed the diagnosis of WSN histopathologically.

Enamel defects of human primary dentition as virtual memory of early developmental events.

BACKGROUND AND AIMS: The objectives of the present study were to investigate the prevalence and the position of enamel defects of primary teeth and hence to estimate the approximate time of an insult. MATERIALS AND METHODS: 121 children aged 3 to 5 years were included in the study. The Modified Developmental De-fects of Enamel Index was used to diagnose and classify the defects. The defects were categorized as hypoplasia, hypocalcification or a combination of them. Each tooth was investigated for occlusal/incisal, middle, cervical, incisomiddle, cervicomiddle and complete crown defects. RESULTS: 55.37% of the children were affected by enamel defects, 23.96% being categorized as hypocalcification and 22.31% as hypoplasia. The enamel defects were more abundant in maxillary primary incisors and mandibular primary canines. Minimum involvement was seen in maxillary primary second molars and mandibular primary lateral incisors. The prevalence of cervical defects in maxillary primary incisors was significantly more than the middle or incisal defects (P < 0.05). The prevalence of incisal defects in mandibular primary incisors was significantly more than the middle or cervical defects (P < 0.05). CONCLUSION: The results revealed a considerable number of enamel defects which are multiple, symmetric and chrono-logically accordant with the estimated neonatal line in primary teeth of healthy children.