Evaluation of Histological Impacts of Three Types of Orthodontic Fixed Retainers on Periodontium of Rabbits

Statement of the Problem: Fixed retainers were developed to maintain incisor alignments after orthodontic treatments. Although the effects of fixed retainers on periodontal health are clinically studied, no studies have still evaluated the histological changes in the periodontium after the placement of thefixed retainers. Purpose: The aim of this study was to evaluate the effects of customised retainers on periodontium histologically. Materials and Method: Forty pairs of maxillary and mandibular central incisors of twenty rabbits were randomly divided into four equal groups: The first group was considered as the control and in the second group, Fiber Reinforced Composite (FRC), in the third group, 0.014 inch stainless steel (SS) wire and in the fourth group, 0.175 inch multistrand stainless steel (MSS) wire were bonded on the labial surfaces of the incisors. After sixty days; animals' periodontium were evaluated histologically. Results: The number of bone resorption lacuna in the control group was significantly less than FRC and 0.014 SS groups. The periodontal vessel count and their diameter in the control group was significantly lower than the other groups. The pulp vessel count and their diameter in controls were significantly more than the 0.014 SS and the 0.175 MSS groups. Conclusion: Findings of this study suggest that FRC fixed retainer might cause detrimental effects on the periodontal ligaments and supporting bone and the 0.014- inch and 0.175- inch fixed retainers can cause hyalinization and possibly the necrosis of the pulp

Evaluation of Histological Impacts of Three Types of Orthodontic Fixed Retainers on Periodontium of Rabbits

ABSTRACT Statement of the Problem: Fixed retainers were developed to maintain incisor alignments after orthodontic treatments. Although the effects of fixed retainers on periodontal health are clinically studied, no studies have still evaluated the histological changes in the periodontium after the placement of thefixed retainers. Purpose: The aim of this study was to evaluate the effects of customised retainers on periodontium histologically. Materials and Method: Forty pairs of maxillary and mandibular central incisors of twenty rabbits were randomly divided into four equal groups: The first group was considered as the control and in the second group, Fiber Reinforced Composite (FRC), in the third group, 0.014 inch stainless steel (SS) wire and in the fourth group, 0.175 inch multistrand stainless steel (MSS) wire were bonded on the labial surfaces of the incisors. After sixty days; animals' periodontium were evaluated histologically. Results: The number of bone resorption lacuna in the control group was significantly less than FRC and 0.014 SS groups. The periodontal vessel count and their diameter in the control group was significantly lower than the other groups. The pulp vessel count and their diameter in controls were significantly more than the 0.014 SS and the 0.175 MSS groups. Conclusion: Findings of this study suggest that FRC fixed retainer might cause detrimental effects on the periodontal ligaments and supporting bone and the 0.014-inch and 0.175-inch fixed retainers can cause hyalinization and possibly the necrosis of the pulp

Assessment of Oral Glycine and Lysine Therapy on Receptor for Advanced Glycation End Products and Transforming Growth Factor Beta Expression in the Kidney of Streptozotocin-Induced Diabetic Rats in Comparison with Normal Rats

Abstract: Background & Aims: Today, diabetic nephropathy is considered to be one of the most common causes of end stage renal disease. Uncontrolled hyperglycemia, and consequently, production of advanced glycation end products activate pathways which play key roles in diabetic nephropathy. Among these pathways, high expression of receptor for advanced glycation end products (RAGE) and transforming growth factor beta (TGF?) are notable. In this study, in order to find compounds which can prevent the incidence or progression of diabetic nephropathy, we examined the effects of glycine and lysine amino acids on expression of RAGE and TGF? in kidney tissue of diabetic rats. Methods: After rendering rats with diabetes with streptozotocin (STZ), they were divided into different groups and were treated with oral 1% glycine and 0.1% lysine in drinking water for 12 weeks. Blood glucose and serum AGEs were measured during this time. Changes in RAGE and TGF? expression were assessed by semi quantitative reverse transcription polymerase chain reaction (RT-PCR) method. Results: Results show that both glycine and lysine administration for 12 weeks not only caused a significant reduction in blood glucose and AGEs in diabetic rats, but also led to a significant reduction in RAGE and TGF? expression in comparison to non-treated diabetic rats. Conclusion: These results show that oral glycine and lysine, as chemical chaperones, have the ability to prevent diabetic nephropathy by decreasing RAGE and TGF? expression. This may be due to the effect of these chemical chaperones in the reduction of hyperglycemia and serum AGEs in diabetic rats. Since the positive effects of these amino acids in diabetic nephropathy have been observed in previous studies, the determination of their dose in future studies seems necessary. Keywords: Receptor for advanced glycation end products (RAGE), Advanced glycation end products (AGEs), Glycine, Lysine, Chemical chaperone

Fatal vanishing bile duct syndrome in Iranian patient with Hodgkin's lymphoma

Key Clinical Message Vanishing bile duct syndrome (VBDS) has been postulated that may be related to Hodgkin's lymphoma (HL). In the present study, we present a 75‐year‐old male patient with HL who received chemotherapy but has not received any radiotherapy. The patient's condition worsened in further days, and he died with the diagnosis of cirrhosis and hepatic failure

The prevalence of clarithromycin-resistant Helicobacter pylori isolates: a systematic review and meta-analysis

Background Knowledge of global clarithromycin (CLA)-resistant rates of Helicobacter pylori (H. pylori) is crucial for decision of the most appropriate eradication therapies with good clinical outcomes. Therefore, this review and meta-analysis aimed to evaluate the global prevalence of the CLA resistance in H. pylori to provide some guidance for selecting the first-line antibiotics. Method A comprehensive search was performed for relevant literature until April 2021 in PubMed, Embase, and Web of Science databases. Freeman-Tukey double arcsine transformation was performed to estimate the weighted pooled prevalence of resistance. Results The meta-analysis included 248 articles. The prevalence of CLA-resistant H. pylori was 27.53% (95% CI [25.41–29.69]). The heterogeneity between reports was significant (I2 = 97.80%, P 0.05). Conclusion Overall CLA resistance rate was 27.53%, worldwide. The difference in CLA resistance rate among the included studies can be due to several reasons such as differences in antibiotic prescription rates in various geographic areas, use of different breakpoints or inaccurate criteria in performed studies, and the emergence of multidrug-resistant (MDR) strains

Molecular typing and antibiotic resistance patterns among clinical isolates of Acinetobacter baumannii recovered from burn patients in Tehran, Iran

Acinetobacter baumannii (A. baumannii) is now considered a highly resistant pathogen to various types of antibiotics. Therefore, tracking the source of its prevalence and continuous control is crucial. This study aimed to determine antibiotic resistance and perform various molecular typing methods on clinical isolates of A. baumannii isolated from hospitalized burn patients in Shahid Motahari Burn Hospital, Tehran, Iran. Hospital isolates were confirmed by phenotypic and molecular methods. Then the sensitivity to different antibiotics was determined using the minimum inhibitory concentration (MIC) method. In order to perform molecular typing, three-locus dual assay multiplex polymerase chain reaction (PCR), multiple-locus variable-number tandem repeat analysis (MLVA), and multilocus sequence typing (MLST) methods were used. Among the 60 isolates collected, the frequencies of multidrug-resistant (MDR) and extensively drug-resistant (XDR) isolates were 90 and 10%, respectively. The most effective antibiotics were colistin with 100% and tigecycline with 83.33% sensitivity. Isolates were 100% resistant to piperacillin/tazobactam and cephalosporins, and 68.3% were resistant to carbapenem. The results of multiplex PCR showed five groups that international clone I (IC I) and IC II were the most common. The MLVA method identified 34 MLVA types (MTs), 5 clusters, and 25 singletons. Multilocus sequence typing results for tigecycline-resistant isolates showed seven different sequence types (STs). Increasing antibiotic resistance in A. baumannii isolates requires careful management to control and prevent the occurrence of the pre-antibiotic era. The results of this study confirm that the population structure of A. baumannii isolates has a high diversity. More extensive studies are needed in Iran to better understand the epidemiology of A. baumannii