Inhibitory motor control in children with attention-deficit/hyperactivity disorder: event-related potentials in the stop-signal paradigm.

BACKGROUND: The aim of the study was to investigate the inhibitory control of an ongoing motor response and to identify underlying neural deficiencies, manifested in event-related potentials, that cause poorer inhibitory performance in children with attention-deficit/hyperactivity disorder. METHODS: A stop-signal paradigm with a primary visual task and auditory stop signal was used to compare performance in 13 children with attention-deficit/hyperactivity disorder and 13 control children, while event-related potentials were recorded simultaneously. RESULTS: Children with attention-deficit/hyperactivity disorder showed poorer inhibitory performance through a slower inhibitory process. Inhibitory processing of auditory stop signals was marked by a frontal N2 component that was reduced in the attention-deficit/hyperactivity disorder group relative to controls. A central positive component (P3) was associated with the success of inhibiting a response, but there were no group differences in its amplitude or latency. CONCLUSIONS: Findings support the hypothesis of deficient inhibitory control in children with attention-deficit/hyperactivity disorder. Slower inhibitory processing appears to be due to a specific neural deficiency that manifests in the processing of the stop signal as attenuated negativity in the N2 latency range.     

The orthopan tomoscintigram — a new application of emission computed tomography for facial bone scanning

The exact regional correlation of findings of facial bone scans, planar or SPECT, to dental orthopan X-ray films (OPT) is difficult because of the very different projection techniques. To improve correlative imaging in this regard a projection algorithm was developed that uses SPECT data of the skull for reconstructing an orthopan tomoscintigraphic projection. Fourteen conventional SPECT slices of the upper and lower jaws were obtained during bone scanning. All mandibular slices were superimposed resulting in a horseshoe shaped structure, which was marked by an ROI which was divided into segments. All 14 SPECT slices were then masked by this segmental ROI, thereby marking the teeth-carrying bone in all slices. The information from this horseshoe like ROI is then transformed into lines. Line by line arrangement results in an orthopan projection, the orthopan tomoscintigram. This new display allows 1:1 true scale superimposition with the X-ray OPT and markedly facilitates correlative imaging.     

Magnetic Forces on Orthodontic Wires in High Field Magnetic Resonance Imaging (MRI) at 3 Tesla

BACKGROUND: In a previous investigation we reported on magnetic forces in the static magnetic field of a 1.5 Tesla MRI system. The aim of the present investigation was to assess forces on orthodontic wires in a high field strength MRI system at 3 Tesla. MATERIALS AND METHODS: Thirty-two different orthodontic wires (21 archwires, eight ligature wires and three retainer wires) were investigated in a 3 Tesla high field strength MRI system (Intera, Philips Medical Systems, Best, The Netherlands). Translational forces were measured by the deflection angle test (ASTM F2052-02), and rotational forces assessed on a 5-point qualitative scale. RESULTS AND CONCLUSION: Translational forces ranged between 43.5 mN and 136.1 mN for retainer wires and between 0.6 mN (Noninium) and 208.4 mN (Orthos Stainless Steel) for steel archwires. Translational forces were up to 53.8 times as high as gravitational forces for retainer wires and up to 54.5 times as high for steel archwires, associated with marked rotational forces for the most part. Archwires manufactured from nickel-titanium, titanium-molybdenum and cobalt-chromium and different ligature wires showed no or negligible forces in the magnetic field. Carefully ligated wires should not present a risk due to translational and rotational forces in the high field MRI system at 3 Tesla.     

Age and gender effects in EEG coherence: III. Girls with attention-deficit/hyperactivity disorder.

OBJECTIVE: This study investigated intrahemispheric and interhemispheric EEG coherences as a function of age in girls with different DSM-IV subtypes of Attention-Deficit/Hyperactivity Disorder (AD/HD). It completes a series of 3 studies aimed at clarifying developmental and gender impacts on the coupling between brain regions in this disorder. METHODS: Three groups of 40 children (AD/HD combined type, AD/HD inattentive type, and normal controls) participated. Each group contained 8 females in each of 5, 1-year age bands from 8 to 12 years. EEG was recorded from 21 sites during an eyes-closed resting condition. Wave-shape coherence was calculated for 8 intrahemispheric electrode pairs (4 in each hemisphere), and 8 interhemispheric electrode pairs, within each of the delta, theta, alpha and beta bands. RESULTS: Developmental effects in intrahemispheric coherences at shorter and longer inter-electrode distances were not as predicted by Thatcher's two-compartment model, contrary to previous findings in boys. Females with AD/HD showed evidence of developmental delay and widespread anomalous elevations in coherence. Girls with AD/HD of the combined type showed similar but greater anomalies than girls with AD/HD of the inattentive type. CONCLUSIONS: Girls with AD/HD show coherence anomalies relative to age- and gender-matched controls, which differ substantially from those shown by boys with AD/HD. These coherence anomalies did not differ in nature between girls with different DSM-IV subtypes of AD/HD, suggesting that subtype differences in girls reflect only symptom severity. SIGNIFICANCE: The data reported here indicate qualitative differences in EEG coherences in girls with AD/HD compared with controls, and quantitative differences between girls with different subtypes of AD/HD. Both sets of effects differ in nature from those previously found in boys with AD/HD, showing the need to carefully consider gender in future studies of AD/HD.     

Interplay of complement and cytokines in the pathogenesis of septic shock.

Sepsis is a clinical syndrome that is usually induced by bacterial infections. It is generally assumed that the syndrome results from an excessive triggering of endogenous inflammatory mediators by the invading microorganisms. These mediators include substances released by activated monocytes, macrophages, endothelial cells and neutrophils such as cytokines, reactive oxygen species and proteases, as well as activation products of coagulation, fibrinolysis, contact and complement systems. Recent studies have suggested that cytokines and complement activation products may have overlapping biological activities. In addition, multiple interactions in vitro as well as in vivo between cytokines and complement have been described. Here we will review some of these recent studies and will discuss their relevance for the pathogenesis of sepsis and septic shock.     

Percutaneous Transhepatic Cholangiodrainage as Rescue Therapy for Symptomatic Biliary Leakage Without Biliary Tract Dilation After Major Surgery

Symptomatic biliary leakage following major upper abdominal surgery is a severe complication resulting in increased morbidity and mortality. Treatment options usually include either endoscopic intervention or surgical revision. These options may be burdened by a high perioperative risk for the patient (e.g., patients with severe disease) or simply may not be possible (e.g., nonpreserved gastroduodenal passage). In the past, percutaneous transhepatic cholangiodrainage did only seem to be a viable option for patients with dilated bile ducts. Here, we present our experience in a consecutive series of patients with symptomatic biliary leakage following major upper abdominal surgery and without dilation of the biliary system that underwent percutaneous transhepatic cholangiodrainage. Percutaneous transhepatic cholangiodrainage was feasible in 15 of 18 patients (83.3%). The procedure was technically not possible in three patients (16.7%). In 10 of the 15 patients (66.6%) with feasible percutaneous transhepatic cholangiodrainage, biliary leakage was definitely controlled without the need for surgical revision. Depending on the experience with the interventional procedure, percutaneous transhepatic cholangiodrainage should be considered as an alternative for treatment of symptomatic biliary leakage instead of immediate reoperation. Presented at the Digestive Disease Week 2005 (DDW), Chicago, IL, May 14–19, 2005 (poster presentation).     

Management of Genital Herpes

Genital herpes simplex virus (HSV) infection has substantial economic and quality-of-life consequences; not least is the risk of transmission to the fetus/infant during parturition with the subsequent effects on the family, society as a whole and healthcare providers. While general screening programs for HSV infection are not cost effective, screening of susceptible subgroups may be acceptable in some circumstances (e.g. immunocompromised patients, presumed discordant heterosexual couples, pregnant women) despite the high costs involved. First-line options for treatment and suppression of genital herpes in Europe and the US include valaciclovir, aciclovir and famciclovir. The established efficacy of valaciclovir, along with its potential for once-daily administration in many patients (versus administration up to five times daily for aciclovir), its positive effect on quality of life, its suppressive efficacy in late pregnancy and its proven reduction of viral transmission between heterosexual discordant partners support the drug’s position as a first-line therapy and suppression option in patients with genital herpes. However, the high acquisition costs compared with aciclovir will affect formulary decisions in some patients, and the favored niche for this drug, at least until evidence of prevention of transmission is demonstrated for other antivirale, would seem to be in the prevention of transmission in susceptible subgroups such as couples discordant for HSV infection (especially male-positive/female-negative couples who are planning a pregnancy), and the treatment and suppression of genital herpes in patients particularly receptive to once-daily administration.Potential disease management programs for genital herpes would thus need to balance the high costs of HSV screening and the relatively high acquisition costs of valaciclovir against the convenience of once-daily administration, the improved quality of life and the proven potential for reduced viral transmission to susceptible partners (with potential for downstream reductions in the overall socioeconomic burden of the disease) associated with oral valaciclovir.