The Effect of Chronic Methylphenidate on Executive Function and Working Memory in Drug-Naïve Children with Attention-Deficit Disorder

Background: The main problem in ADHD patients is disinhibition, while ADD patients mostly suffer from slow cognitive speed. Although studies have shown that children with ADHD have deficits in executive function and working memory, and that acute use of Methylphenidate improves these functions, less study has been done on ADD patients. Methods: A four weeks, experimental, clinical trial was conducted with MPH 1 mg/kg/dose. Participants were 20 children aged 6-11 years with diagnosis ADD. Neuropsychological performance was assessed with scales taken from the Cambridge Neuropsychological Test Automated Battery. Results: Methylphenidate improved problems in some aspects of Stocking of Cambridge test including minimum moves, mean subsequent thinking time and in mean moves, between errors, strategy and total error aspects of Spatial Working Memory. It had no effect on Spatial Span and Intra/Extra Dimensional subscales. Conclusions: Studies show that ADHD patients have defect on all executive and working memory tests and acute and not chronic use of Methylphenidate improves their performance. This different effect of chronic Methylphenidate on ADD and ADHD patients is another sign of different brain involvements in these two subgroups.  Keywords: Attention Deficit Hyperactivity Disorder, Attention Deficit Disorder, Methylphenidate, Executive Function, Working Memory Â

B-cell Lineage Study in Patients with Juvenile Idiopathic Arthritis

Objective: Juvenile idiopathic arthritis (JIA) is the most common rheumatic disease in children. The exact causes of disease are still poorly understood. It seems that B cells have several functions in JIA, including production of autoantibodies, antigen presentation, production of cytokines, and activation of T cells. Here, we aimed to evaluate B-cell lineage and its precursors in the bone marrow of patients with JIA. Methods: Twenty consecutive patients with JIA were enrolled in this study. JIA is subdivided into three groups of Pauciarticular, Polyarticular, and Systemic JIA. Bone marrow mononuclear cells were separated. Then we analyzed the immunophenotype of the JIA patients by flow cytometry. After separation, the mononuclear cells were stained specific for B cell lineage [CD10, CD19 and CD20], T cell lineage [CD3] and non specific lineage [CD34, HLA-DR and TdT]. Findings: Flow cytometric study of bone marrow showed that JIA patients had low level of CD10, CD19, and CD20. Polyarticular patients had lower level of D10, CD19, and CD20 than pauciarticular JIA patients and systemic onset JIA patients had lower levels than both of them. Conclusion: Decreasing of B cell precursor in bone marrow is one of mechanisms for pathogenesis of JIA and the more decreased B cell precursors in bone marrow are, the worst severity of the disease is. Significant differences in CD10 content of bone marrow were detected between the polyarticular and pauciarticular groups. So, it seems that polyarticular JIA patients had lower percentage of pre B cell stage