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.     

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).     

Combinatorial expression patterns of heparan sulfate sulfotransferases in zebrafish: I. The 3-O-sulfotransferase family.

Heparan sulfate (HS) is an unbranched chain of repetitive disaccharides, which specifically binds ligands when attached to the cell surface or secreted extracellularly. HS chains contain sulfated domains termed the HS fine structure, which gives HS specific binding affinities for extracellular ligands. HS 3-O-sulfotransferases (3-OST) catalyze the transfer of sulfate groups to the 3-O position of glucosamine residues of HS, a rare, but essential HS chain modification required for HS fine structure. We report here the first characterization and developmental expression analysis of the 3-OST gene family in a vertebrate. There are eight 3-OST genes in zebrafish: seven genes with homology to known 3-OST genes in mouse and human, as well as a novel, 3-OST-7. A phylogenetic comparison of human, mouse, and zebrafish indicates the 3-OST family can be subdivided into two distinct subgroups. We examined the mRNA expression patterns in several tissues/organs throughout early zebrafish development, including early cleavage stages, somites, brain, internal body organ primordial, and pectoral fin development. The 3-OST gene family has both specifically expressed and ubiquitously expressed genes, suggesting in vivo functional differences exist between members of this family.     

The effect of simulator training on clinical skills acquisition, retention and transfer

Context  Prior research has demonstrated that residents have poor clinical skills in cardiology and respirology. It is not clear how these skills can be improved because the number of patients with suitable clinical findings whose cooperation might help residents to better develop these clinical skills is limited.
Objectives  Our objective was to evaluate the effect of training on a cardiorespiratory simulator (CRS) on skills acquisition, retention and transfer.
Methods  We randomly allocated 146 students to CRS training in either chest pain or dyspnoea and compared each student's performance on the clinical presentation in which he or she had received CRS training with performance on the control presentation.
Results  Immediately after training, students were more accurate in identifying abnormal clinical findings on the CRS (70.0% versus 52.2%; d = 7.6, P  < 0.0001) and showed improved diagnostic performance (72.1% versus 55.6%; d = 4.3, P  = 0.0007) on the training clinical presentation. At the end of the course they were still better at identifying abnormal findings (57.1% versus 51.7%; d = 2.5, P  = 0.004) and diagnosing correctly (50.0% versus 38.1%; d = 3.0, P  = 0.002) on problems included in the training clinical presentation. However, they showed no difference between training and control presentations in diagnostic performance when required to transfer their skills between problems (45.9% versus 43.8%; P  = 0.5) or in performance on multiple-choice questions (64.1% versus 63.6%; P  = 0.8).
Conclusions  Students can acquire and retain clinical skills with CRS training, but demonstrate limited ability to transfer these to other problems. Further studies are needed to explore ways of improving learning and transfer with CRS training.     

Botulinum Toxin A in the Treatment of Chromhidrosis

Background. Chromhidrosis is an uncommon disorder characterized by secretion of colored sweat by apocrine glands, typically localized to the face or axilla. The current treatments available for chromhidrosis are time consuming and frequently ineffective.
Objective. Our purpose is to demonstrate a novel approach to the treatment of apocrine chromhidrosis.
Methods. We report a case of apocrine chromhidrosis successfully treated with botulinum toxin A (BTX-A; Botox).
Results. BTX-A therapy successfully controlled facial chromhidrosis, and the effects were visible at 19 weeks post-treatment. The therapeutic benefits may be attributed to its inhibitory effects on cholinergic stimulation, adrenergic stimulation, and substance P release, although further studies are necessary to elucidate the precise mechanism of action.
Conclusion. This report demonstrates a new therapeutic approach to patients suffering from chromhidrosis.