Graphene quantum dots: Synthesis,characterization, cell viability,genotoxicity for biomedical applications

We report the synthesis and applications of a novel N-doped graphene quantum dots (GQDs) using hydrothermal reaction between citric acid and p-aminophenol. The synthesized N-doped GQDs have been characterized physico-chemically and evaluated its antioxidant, antimicrobial, DNA binding and cleavage activities. siRNA loading studies were performed and their effects on cells were evaluated. Obtained results indicate that monodisperse solution of N-doped GQDs has been obtained with particles size ca. ～10.9 ± 1.3 nm. UV–Vis spectroscopy studies of the interactions between the N-doped GQDs and calf thymus DNA (CT-DNA) showed that the compound interact with CT-DNA via both intercalative and electrostatic binding. The DNA cleavage study showed that the N-doped GQDs cleaved DNA without any external agents. The antioxidant activity of N-doped GQDS was very active when compared to BHT. As the concentration of the compound increased, the antioxidant activity also increased. Cell viability assay demonstrated that the Ndoped GQDs showed cell viability (70%) when the concentration reached 200 μg/mL for A549 and also MDA-MB-231, 150 μg/mL for NIH-3T3 cell lines at 24 h incubation. N-doped GQDs were coated with Eudragit RS 100 and EphA2-siRNA was loaded. As a result of the studies on these formulations, it was concluded that there may be significant effects on A549 cells. The microscopy results revealed that N-doped GQDs was quickly internalized into the cell. Our novel N-doped-GQDs with siRNA are candidate for in situ tumor suppression via DNA and mRNA breakage.     

The long-term results of childhood acute lymphoblastic leukemia at two centers from Turkey: 15 years of experience with the ALL-BFM 95 protocol

Dramatic progress in the treatment of childhood acute lymphoblastic leukemia (ALL) has been achieved during the last two decades in Western countries, where the 5-year event-free survival (EFS) rate has risen from 30 to 85 %. However, similarly high cure rates have not always been achieved in all centers in developing countries due to limited sources. We evaluated the treatment results of the ALL-Berlin–Frankfurt–Münster (BFM) 95 protocol as used between 1995 and 2009 in the pediatric hematology departments of two university hospitals. A retrospective analysis of 343 children newly diagnosed with ALL (M/F 200/143, median age 6.8 years) was performed. The overall survival (OS) and EFS according to age, initial leukocyte count, immunophenotype, chemotherapy responses (on days 8, 15, and 33), and risk groups were analyzed by Kaplan–Meier survival analysis. Median follow-up time was 6.4 years. Complete remission was achieved in 97 % of children. Five-year EFS and OS were found to be 78.4 and 79.9 %, respectively. Children younger than 6 years old had significantly better EFS and OS (83.7 and 85.2 %) than children aged ≥6 years (71.4 and 72.8 %). Adolescents achieved 63 % EFS and 65 % OS. Patients who had initial leukocyte counts of <20?×?10⁹/L had better EFS and OS (82.2 and 84.6 %) than children with higher initial leukocyte counts (72.6 and 72.6 %). EFS for B-cell precursor and T-cell ALL was 81.5 and 66.7 %, respectively. Children with a good response to prednisolone on day 8 (87 %) achieved significantly better EFS and OS (81.2 and 81.9 % vs. 55.3 and 60.5 %). Children whose bone marrow on day 15 was in complete remission had higher EFS and OS (83.7 and 86.6.1 % vs. 56.4 and 61.5 %). Children in the standard-risk and medium-risk groups obtained statistically significantly higher EFS (95.5 and 82.7 %) and OS (97.7 and 82.3 %) compared to the high-risk group (EFS 56.3 %, OS 63.4 %). The relapse rate was 14.8 %. The median relapse time from diagnosis was 23.2 months. Death occurred in 69 of 343 patients (20.1 %). The major causes of death were infection and relapse. None of the patients died of drug-related toxicity. The ALL-BFM 95 protocol was applied successfully in these two centers. In developing countries in which minimal residual disease cannot be monitored, this protocol can still be used with high survival rates.     

Trabecular structural changes in the mandibular condyle caused by degenerative osteoarthritis: a comparative study by cone-beam computed tomography imaging

Oral Radiology - Temporomandibular osteoarthritis causes pain and loss of function. In advanced cases, it may also result in destruction of joint cartilage surfaces and bone structure. This study...     

Association of simple hematological parameters with disease manifestations,activity, and severity in patients with systemic sclerosis

Clinical Rheumatology - Neutrophil-to-lymphocyte ratio (NLR), monocyte-to-lymphocyte ratio (MLR), mean platelet volume (MPV), and red cell distribution width (RDW) may potentially reflect...     

Lumbar puncture requirement in acute hemiparesis: Diagnosis of tuberculous meningitis after hemiparesis in a child

Background

Infections are an important acquired cause of cerebral arteriopathy. Tuberculous (TB) meningitis leading to infectious cerebral vasculopathy is a rare cause of acute hemiparesis.

Case report

A 14-year-old male patient was examined after acute hemiparesis developing within 1 day. Neurological examination revealed total hemiplegia on the left side. Brain MRI findings showed bilateral focal T2-weighted signal hyperintensity in the subcortical and deep white matter regions. There were also areas of restricted diffusion in the right basal ganglia. Although the father had a history of pulmonary TB, the patient had not been given TB prophylaxis because of PPD negativity. At lumbar puncture, opening cerebrospinal fluid (CSF) pressure was 50 cm/H20, CSF protein 66.9 mg/dL, and glucose 54 mg/dL (concurrent blood glucose 93 mg/dL); 170 polymorphonuclear leukocytes per cubic millimeter were present in CSF. Following tests for TB, treatment was started immediately with four anti-TB drugs. TB PCR of CSF and acid-fast bacteria (AFB) staining in gastric aspirate were positive. At clinical follow-up, the patient was able to walk with support at the end of the first month.

Conclusion

Various infectious agents have been reported as causes of cerebral vasculopathy. TB, which affects a significant number of patients worldwide, should be kept in mind in terms of cerebral vascular complications. Lumbar puncture is essential in order to diagnose TB meningitis.     

Investigation of Dynamic Thiol/Disulfide Homeostasis and Nitrosative Stress in Patients with Wilson Disease

Background: Wilson disease (WD) is an autosomal recessive inherited disorder of copper (Cu²⁺) metabolism, resulting in Cu²⁺ accumulation and liver and central nervous system toxicity. Oxidative stress may have a role in the pathogenesis of Wilson disease, but the roles of thiol/disulfide homeostasis and nitrosative stress have not been examined. The purpose of this study was to evaluate whether there is a modification in thiol/disulfide homeostasis and nitrosative stress in patients with Wilson disease.Methods: A total of 50 patients with Wilson disease (42 under drug treatment and 8 newly diagnosed patients with no drug treatment) and 50 healthy gender- and age-matched controls were enrolled for this study. Serum native thiol and total thiol levels were measured with a spectrophotometric method. The number of disulfide bonds and the related ratios were determined from these measurements. Serum nitric oxide (NO) and 3-nitrotyrosine (3-NT) levels were analyzed using chemiluminescence and ELISA assays, respectively.Results: The average native thiol levels of the patient group under drug treatment were found to be markedly higher than the levels of controls (P < .05). We detected no marked changes in total thiol and disulfide levels, and disulfide/total thiol, disulfide/native thiol, or native thiol/total thiol ratios between groups. We found significant elevations in NO levels in Wilson disease group before drug treatment, and the 3-NT levels in the Wilson disease groups prior to (P < .05) and under drug treatment (P < .01), when compared to controls.Conclusion: Our data are the first to show that nitrosative stress and thiol/disulfide homeostasis can contribute to the pathogenesis of Wilson disease.     

Corrective Effect of Verbascoside on Histomorphological Differences and Oxidative Stress in Colon Mucosa of Rats in Which Colon Ischemia–Reperfusion Injury was Induced

BackgroundThis study aims to show the corrective effect of verbascoside on histomorphological and biochemical differences in the colon mucosa of rats in which colon ischemia–reperfusion (I/R) injury was induced.Methods: Fifty Sprague Dawley male rats were divided into 5 groups, of control, sham, ischemia (I), I/R, and I/R+verbascoside.Ischemia and reperfusion were applied to the suitable groups for 30 minutes and 120 minutes respectively, and 10 mg/kg verbascoside was administered intraperitoneally. Histomorphological assessment was done in the colon tissues obtained, and the goblet cells were assessed using the Alcian blue method. Proliferating cell nuclear antigen (PCNA), TUNEL, and hypoxia-induced factor 1 (HIF-1α) assays were used to assess oxidative stress with the immunohistochemical method. Malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), total antioxidant status (TAS), total oxidant status (TOS), oxidative stress index (OSI), and total thiol (TT) levels were checked, for a biochemical analysis of oxidative stress.Results: Compared with the I/R group, histomorphological differences were seen to be corrected in colon epithelium in the I/R+verbascoside group. The goblet cell number increased and cell proliferation was increased, as seen with the PCNA assay; and apoptosis was decreased, as seen with the TUNEL assay. HIF-1α expression also decreased in the drug group. In the drug group, SOD, GSH-Px, TAS, and TT levels increased, but TOS, OSI, and MDA levels decreased.Conclusion: It was seen that verbascoside had a corrective effect on histomorphological and biochemical differences caused by I/R injury.     

Examination of the relationship between technology use of 5–6 year-old children and their social skills and social status*

The primary objective of this study is to determine the predictive effect of technology use durations of 5–6 year-old children on their social skill levels and social status. In this study, children’s technology usage is restricted to the use of television, portable computers, tablets and smartphones. The sample group of the study consisted of 162 children aged 5 and 6 years old who are actively enrolled in seven kindergartens. The data required for the study were obtained from children, parents and teachers. The ‘Determination of Use of Technology by Children–Parent Form’, the ‘Social Skills Evaluation Scale’, ‘The Picture Sociometry Scale’ and ‘The Personal Information Form’ were used. The results revealed that the use of mobile technologies had no predictive effect on the social skill level, whereas, some mobile devices have predictive effects on the social preference and social impact.