Cytogenetic Effects of Chronic Methylphenidate Treatment and Chronic Social Stress in Adults with Attention-Deficit/Hyperactivity Disorder.

INTRODUCTION: Methylphenidate (MPH) is widely used to treat childhood and adult attention-deficit/hyperactivity disorder (ADHD). However, there are still safety concerns about side effects in long-term treatment. The aim of this study was to assess cytogenetic effects of chronic MPH treatment in adult ADHD and to find out if chronic social stress is attenuated by medication and to investigate whether chronic psychosocial stress leads to mutagenic effects by itself. METHODS: Lymphocytes for micronucleus assay and saliva samples for cortisol measurement were collected from adult ADHD patients and healthy controls. Stress exposure of the last 3 months was assessed by TICS (Trier Inventory for Chronic Stress). RESULTS: We could not detect an influence of MPH treatment on cytogenetic markers. ADHD patients displayed significantly higher chronic stress levels measured by TICS compared to healthy controls which were influenced by duration of MPH treatment. ADHD patients also showed significantly lower basal cortisol levels. DISCUSSION: We could corroborate that there are neither cytogenetic effects of chronic stress nor of chronic MPH intake even after several years of treatment.

Lithium-induced Clock Gene Expression in Lymphoblastoid Cells of Bipolar Affective Patients.

INTRODUCTION: Disturbances of circadian rhythms occur in all episodes of bipolar disorder (BD). Lithium, as gold-standard in the maintenance treatment of BD, is known to influence circadian processes. METHODS: In a pilot study lymphoblastoid cell lines (LCLs) were generated from 8 BD patients and 6 healthy controls. The LCLs were treated with lithiumchloride (LiCl) for 3 weeks. Cell cycles were then synchronized and expressional analysis by quantitative Real Time PCR was done. RESULTS: BD and controls differed in the period length regarding DBP (albumin D-box binding protein) expression and DBP expression was also influenced by lithium treatment. Furthermore, baseline DBP expression was significantly different between non-treated BD and healthy controls. None of the other analyzed circadian genes showed to be influenced by chronic lithium treatment or to be differentially regulated due to the diagnosis. DISCUSSION: We here show that chronic lithium treatment of LCLs leads to decreased expression of the clock gene DBP, rendering DBP a lithium-regulated gene. We could confirm the role of the circadian clock as well in lithium mode of action as in the pathomechanisms of BD although future studies with a greater number of participants and cell lines are needed.

Evaluation of formats for aircraft control/display units.

Control/display unit (CDU) technology has been advancing more rapidly than the human factors research needed to establish guidelines for the design of display formats. Such guidelines must be established and followed to ensure effective and efficient human performance in the cockpit environment. A preliminary study which addressed the issue of defining an optimal CDU display format design was completed. Subjects were asked to search visually alphanumeric displays for a single piece of information and indicate when it was found. Data were collected on the elapsed time to isolate the information as well as the accuracy of the information retrieval. Ten formats of two information densities each were evaluated. Each format contained labels and associated data for typical flight information such as communications data (radio type and frequency) and navigation data (waypoint identifier, longitude and latitude). The ten basic format designs were developed by changing the location relationship between the labels and their associated data. Data were collected while subjects did and did not perform a two-dimensional tracking task. Preliminary findings indicate that both format design and density affect operator response time and response accuracy. Implications of the results for the design of cockpit displays are discussed.