Influence of silver nanoparticles on resin-dentin bond strength durability in a self-etch and an etch-and-rinse adhesive system

OBJECTIVES: This study evaluated the effect of dentin pretreatment with silver nanoparticles (SNPs) and chlorhexidine (CHX) on the microshear bond strength (µSBS) durability of different adhesives to dentin. MATERIALS AND METHODS: Occlusal surfaces of 120 human molars were ground to expose flat dentin surfaces. The specimens were randomly assigned to six groups (n = 20). Three groups (A, B, and C) were bonded with Adper Single Bond 2 (SB) and the other groups (D, E, and F) were bonded with Clearfil SE Bond (SEB). Dentin was pretreated with CHX in groups B and E, and with SNPs in groups C and F. The specimens were restored with Z250 composite. Half of the bonded surfaces in each group underwent µSBS testing after 24 hours and the other half was tested after 6 months of water storage. RESULTS: SNP application was associated with a higher µSBS than was observed in the CHX and control groups for SEB after 24 hours (p < 0.05). A significantly lower µSBS was observed when no dentin pretreatment was applied compared to dentin pretreatment with CHX and SNPs for SB after 24 hours (p < 0.05). The µSBS values of the 6-month specimens were significantly lower than those obtained from the 24-hour specimens for all groups (p < 0.05). This decrease was much more pronounced when both adhesives were used without any dentin pretreatment (p < 0.05). CONCLUSIONS: SNPs and CHX reduced the degradation of resin-dentin bonds over a 6-month period for both adhesive systems.

Frequency of NRAS gene mutation in wild type KRAS and BRAF colorectal cancers; a single center study

Background: Incidence of colorectal cancer is increasing in countries such as Iran. Molecular biomarkers play very important role in the diagnosis, treatment, and prognosis of this cancer. Mutation in the RAS family [including KRAS and NRAS] is one of these important molecular biomarkers, which should be tested before starting treatment with anti-EGRF [Epidermal growth factor] drugs

Objectives: There has been very few reports about the frequency of NRAS mutation from Iran and no study from south of the country. In this article we will describe our experience about the frequency of NRAS mutation in colorectal cancers from the largest referral center in the south of Iran

Methods: During 5 years [2011-2015], we had 52 cases of colorectal cancers with wild type KRAS and BRAF in the hospitals affiliated to Shiraz University of Medical Sciences with enough tissue for molecular studies. NRAS mutation analysis was performed on paraffin embedded formalin fixed tissue of these cases by polymerase chain reaction [PCR]-sequencing method

Results: Among these 52 cases of colorectal cancer with wild type KRAS and BRAF, there has been 3 [5.7%] cases with mutant NRAS. One of the mutations has been in codon 12 and two in codon 61. No mutation in codon 13 was found. All the three cases were women with stage IV and well differentiated histomorphology

Conclusion: Our results showed that frequency of NRAS mutation in colorectal cancer is rare, which is very close to other studies from different geographic areas of the world

Molecular and immunohistochemical study of platelet derived growth factor receptor alpha in kit negative gastrointestinal stromal tumors; the first report from Iran

Background: Gastrointestinal stromal tumors [GISTs] are potentially malignant tumors; however their behavior and response to treatment is dependent on the type of mutation and immunohistochemical expression of antigens. It is recommended to perform routine molecular and immunohistochemical tests in KIT and platelet derived growth factor receptor alpha [PDGFRA] molecules for making decision regarding targeted therapy and prediction of the behavior of the tumor

Objectives: There has been no study from Iran regarding the PDGFRA mutational analysis in GISTs. In this study, for the first time from Iran, we performed immunohistochemical and molecular analysis of PDGFRA molecule on GISTs

Methods: In a cross-sectional study during 7 years [2008-2014] on 50 untreated non-recurrent non-metastatic newly diagnosed GISTs, molecular analysis and immunohistochemical staining for PDGFRA were performed and findings were compared with different clinicopathological characteristics

Results: During the 7 years, 50 cases of GISTs according to the above mentioned criteria were found. 17 cases were negative for KIT mutation. Of them, 15 [30%] were positive for either exon 12 or 18 mutation of PDGFRA. These cases showed more epithelioid morphology and the number of mitotic figures were lower than PDFRA negative GISTs. Also according to the criteria for risk assessment, it seems that PDGFRA mutant GISTs are rarely in the high risk category

Conclusion: PDGFRA mutant GISTs are common in Iranian population and it is recommended to perform mutation analysis for PDGFRA in every GIST with wild type KIT and epithelioid morphology

Low incidence of alpha-1 antitrypsin deficiency among babies with prolonged jaundice

alpha-1 antitrypsin [AAT] deficiency is one of the most important genetic causes of childhood liver diseases in some parts of the world, but its geographic distribution is highly variable. There are many reports from Asian countries such as India, the Philippines, and China which show a very low incidence of this disease. However few studies exist from Iran regarding this genetic deficiency as the cause for prolonged neonatal jaundice. In this study we attempt to investigate the possible role of AAT deficiency as a cause of prolonged neonatal jaundice in the largest pediatric referral center of Southern Iran. We included 126 neonates with the clinical diagnosis of neonatal cholestasis in this study. Polymerase chain reaction-restriction fragment length polymorphism [PCR-RFLP] was performed on the extracted DNA from their blood samples. DNA sequencing confirmed the results of the PCR-RFLP tests. All patients were genetically normal regarding level of AAT, i.e., all were MM homozygotes. AAT deficiency is a rare disease in Iran and is not a major cause of neonatal cholestasis in this country