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.     

Rotatory palmar subluxation of the lunate in post-traumatic ulnar carpal translocation

Post-traumatic ulnar carpal translocation is a rare, severe ligamentous injury to the wrist. Radiologic findings include widening of the radiocarpal joint space at the radial styloid process and ulnar displacement of the carpus. Less than 50% of the lunate articulates with the radius in the neutral position; the lunate is tilted dorsally with palmar subluxation due to a ruptured radioscapholunate (RSL) ligament. This malposition should be called rotatory palmar subluxation of the lunate (RPSL), by analogy to rotatory subluxation of the scaphoid (RSS). In contrast to dorsiflexed intercalated segment instability (DISI), in RPSL the RSL ligament is ruptured and, in the majority of cases, the scapholunate ligament remains intact. A prompt diagnosis should lead to successful treatment.     

Bone disorders following total gastrectomy

Bone disorders following gastrectomy were studied by measuring absolute and relative bone mineral density of the Wards triangle, serum 1,25-(OH)₂-D, alkaline phosphatase, and total serum calcium. The subjects were 20 males who had undergone total gastrectomy not more than three months previously (group A₁). Seventeen of these patients were reviewed three years later (group A₂). Absolute and relative bone density were significantly lower in group A₂ than in A₁ (0.52 ± 0.011 g/cm² versus 0.6 ± 0.014 g/cm²,P<0.01 and 85.5 ± 1.4% age-matched control versus 95 ± 1.3%,P<0.01). 1,25-(OH)₂-D was significantly lower in group A₂ than in group A₁ (14.3 ± 0.97 pg/ml versus 20.6 ± 1.02 pg/ml,P<0.01). There was no difference in alkaline phosphatase and calcium serum concentration. The mean weight loss was 6.26 ± 0.57% over the follow-up period, and weight loss correlated with absolute and relative bone density (r=–0.74,P<0.01). There was a positive correlation between 1,25-(OH)₂-D and absolute or relative bone density (r=0.67,r=0.62 andP<0.01). These data suggest that bone density decrease has already occurred three years after total gastrectomy and is positively correlated to 1,25-(OH)₂-D deficiency. As no differences in serum alkaline phosphatase and serum calcium concentration were found, these factors are of little value for the early detection of postgastrectomy bone disorders, whereas weight loss is a valuable screening parameter.     

Lens opacity in patients with hypercholesterolemia and ischaemic heart disease

Lens opacity studies were performed using an electronic Lens Opacity Meter (Interzeag Opacity Lensmeter 701) in a population (n = 321) with ischaemic heart disease. These patients are participating in a trial targetting at the reduction of mortality and incidence of myocardial infarction using a cholesterol-lowering drug, simvastatin. A separate study to evaluate the reliability of the method showed good reproducibility. Repeated measurements after a short time-interval (2–10 days) gave statistically lower opacity values either due to a change in lens transparency or perhaps a change in pigment and cell dispersion in the acqueous caused by repeated mydriasis. Lens opacity values showed a highly significant positive correlation to age. Serum cholesterol, systolic blood pressure and smoking habits showed no significant correlations to the levels of lens opacity when adjustments for age were made.Abbreviations HMG-CoA hydroxy-methylglutarylcoenzyme A - 4S Scandinavian Simvastatin Survival Study - LOM lens opacity meter     

X-chromosomale Adrenoleukodystrophie

Ohne Zusammenfassung Prof.Dr. J.G?rtner Zentrum Kinderheilkunde, P?diatrie II, Kinderheilkunde mit Schwerpunkt Neurop?diatrie, Universit?tsklinikum, Georg-August Universit?t G?ttingen, Robert-Koch-Strasse 40, 37075 G?ttingen, E-Mail: gaertnj@med.uni-goettingen.de     

Primäre ziliare Dyskinesie

Primary ciliary dyskinesia (PCD) is an autosomal recessive disease characterized by abnormal ciliary motion and impaired mucociliary clearance. The prevalence of PCD is approximately 1:20,000 live births. Since cilia are common in many organs of the body, there is a wide variety of clinical manifestations in patients with PCD. Due to an extensive genetic heterogeneity the course of the disease varies largely, but with increasing age, the clinical symptoms are dominated by repeated respiratory infections and ultimately respiratory insufficiency. In the presence of situs inversus, which is observed in 50% of affected individuals, the diagnosis is easy, In cases of doubt, analyses of the kinetics and infrastructure of the cilia are necessary. The treatment of PCD is symptomatic. With optimal medical and physiotherapeutic management, the prognosis quoad vitam is good and life expectancy is nearly normal.     

The traumatic dural sinus injury — a clinical study

Summary In a period of 13 years 978 cases of severe head injuries were operated on in our clinic. An analysis of the medical reports includes injuries of the superficial dural sinus (39 cases=4%): among these injuries of the anterior and central part of the superior sagittal sinus (66 per cent), injuries of the transverse sinus (18 per cent), injuries of the posterior part of the superior sagittal sinus (8 per cent), and combined injuries of different dural sinuses (8 per cent).Clinical data, i.e. the causes of accident, radiological examination results, intracranial lesions, operation technqiues and outcome are analysed and discussed. The analysis of cases with dural sinus injuries shows a high mortality rate (total mortality rate: 16 patients=41%; intra-operative mortality rate: 8 patients=20%).