[Orbital tumors]

Computed tomography (CT) and magnetic resonance imaging are the modalities of choice in the assessment of orbital neoplasms. Careful interpretation of the characteristic radiological features usually leads to the correct diagnosis; however, some of the lesions look very similar and are difficult to differentiate from each other. This contribution provides an overview of tumors of the eye and orbit and their appearance on CT and magnetic resonance imaging.

Long-term results with Matrix coils vs. GDC: an angiographic and histopathological comparison

INTRODUCTION

The aim of the study was to compare standard platinum Guglielmi detachable coils (GDC) with coated platinum coils (Matrix; both Boston Scientific, Fremont, CA) regarding handling, complications, occlusion and recanalization rate after 3 and 6A months.

METHODS

Aneurysms in the right common carotid artery were created in 25 rabbits. The animals were divided into five groups of five animals each. The animals of group 1 (the control group) received no treatment of the induced aneurysms, the animals of groups 2 and 3 (killed at 3 and 6A months) were treated with standard GDC, and the animals of groups 4 and 5 (killed at 3 and 6A months) were treated with Matrix coils.

RESULTS

Histopathological evaluation showed organized thrombus formation and connective tissue with neovascularization around the implanted coils in all the treated groups. The achieved occlusion rates in groups 2 and 3 were identical to those in groups 4 and 5. Thus the long-term results of aneurysm treatment with GDC and Matrix coils show no differences regarding occlusion and recanalization rates. The only noticeable difference was the difference in handling. More force was required to pushing the Matrix coils forward through the microcatheter and there was more friction in coil interaction in the aneurysm.

CONCLUSION

The bioactive coating of the Matrix coil produces no significant benefit in achieving higher occlusion and lower recanalization rates, and the coil is more difficult to handle. Future bioactive coils must be shown to produce significantly better long-term results than GDC and their ease of handling has to be improved.

Bifunctional electrocatalysis in pt-ru nanoparticle systems

Pt-Ru alloys are prominent electrocatalysts in fuel cell anodes as they feature a very high activity for the oxidation of reformate and methanol. The improved CO tolerance of these alloys has been discussed in relation to the so-called ligand and bifunctional mechanisms. Although these effects have been known for many years, they are still not completely understood. A new approach that bridges the gap between single crystals and practical catalysts is presented in this paper. Nanoparticulate model systems attached to an oxidized glassy carbon electrode were prepared by combining both ligand-stabilized and spontaneously deposited Pt and Ru nanoparticles. These electrodes showed very different voltammetric responses for CO and methanol oxidation. The cyclic voltammograms were deconvoluted into contributions attributed to Pt, Ru, and Pt-Ru contact regions to quantify the contribution of the latter to the bifunctional mechanism. Scanning transmission electron microscopy confirmed the proximity of Pt and Ru nanoparticles in the different samples.

[Cavernous malformations]

Cavernomas of the CNS may involve brain parenchyma as well as the spinal cord and belong to those cerebrovascular malformations that have no arteriovenous shunt and thus are generally angiographically occult. Contrary to computed tomography (CT), which is generally suited to reveal calcifications or acute bleeding, magnetic resonance imaging (MRI) enables detection of even small cavernomas. A frequently associated venous anomaly is helpful for correct diagnosis.

[Type I neurofibromatosis and megadolichobasilar artery]

Intracranial vascular malformations are rare but tend to appear more frequently than usual in patients with type I neurofibromatosis (NFI). Aneurysms of the basilar artery have been described four times so far. We report two cases of 51- and 62-year-old patients with type I neurofibromatosis who showed long fusiform dilation of the basilar artery. Clinically both patients presented with locked-in syndrome and died 15 and 11 days after admission. The diagnosis was confirmed by autopsy. These are the first published cases of locked-in syndrome following thrombosis of a megadolichobasilar artery in association with neurofibromatosis I. Our results show that cerebral vascular malformations are found more frequently than random chance would predict in patients with NF I.

[Supratentorial tumors]

Magnetic resonance imaging is a routine diagnostic measure for a suspected intracerebral mass. Computed tomography is usually also indicated. Further diagnostic procedures as well as the interpretation of the findings vary depending on the tumor location. This contribution discusses the symptoms and diagnostics for supratentorial tumors separated in relation to their intra- or extracranial location. Supratentorial tumors include astrocytoma, differentiated by their circumscribed and diffuse growth, ganglioglioma, ependyoma, neurocytoma, primitive neuroectodermal tumors (PNET), oligodendroglioma, dysem-bryoplastic neuroepithelial tumors (DNET), meningoangiomatosis, pineal tumors, hamatoma, lymphoma, craniopharyngeoma and metastases. The supratentorial extracranial tumors include the choroid plexus, colloid cysts, meningeoma, infantile myofibromatosis and lipoma. The most common sub-forms, especially of astrocytoma, will also be presented.

[Spinal infections]

Regardless of the compartment involved, imaging of spinal infections and other spinal inflammatory diseases must be performed by magnetic resonance imaging (MRI). This allows early detection of changes in disk space or vertebral bodies. Associated paraspinal and epidural masses are depicted. However, in spinal cord inflammation MRI has a very limited specificity and cannot usually differentiate between the wide array of possible causes of intramedullary lesions. This article covers a spectrum of inflammatory lesions of the spinal cord.

Dysphagia due to Triple A Syndrome: Successful Treatment of Achalasia by Balloon Dilatation

Triple A syndrome is a rare autosomal recessive inherited disorder which is characterized by alacrima, adrenal insufficiency, and achalasia. We report on a 14-year old girl with dysphagia, regurgitation, and vomiting since 5 years. At the age of five years an Addison crisis was diagnosed and cortisone substitution was initiated. In addition, the patient had episodes of conjunctivitis. Severe esophagitis and candida infection were diagnosed by esophago-gastro-duodenoscopy and treated with omeprazole and fluconazole. The esophageal barium swallow was typical for achalasia. Medical treatment of achalasia with oral nifedipine resulted only in a partial and temporal improvement. But after seven balloon dilatations dysphagia and nocturnal coughing improved clearly and a remarkable gain of weight could be seen. Direct sequencing showed a homozygous nonsense mutation in exon 11 of the AAAS gene leading to truncation at position 342 of the 546 amino acid protein.

CONCLUSION

Triple A syndrome has to be considered in patients with dysphagia. In our patient, the absence of tears since birth followed by adrenal insufficiency were early signs of the triple A syndrome. Balloon dilatation of the esophago-gastric junction is an effective treatment, which can avoid surgical interventions.

Infratentorielle Tumoren

This article gives an overview concerning the typical infratentorial tumors of adults.

MR-Spektroskopie bei Hirntumoren

MRT allows the anatomical visualization of intracerebral space-occupying lesions, and when magnetic resonance spectroscopy (MRS) is used in routine clinical practice it can give more information and be helpful in the diagnosis of such lesions. In MRS with long echo times for nerve tissue there are five metabolites that are particularly significant: N-acetyl aspartate (NAA), creatine, choline, lactate, and lipids. NAA levels are lowered in the presence of intracerebral tumors. Creatine is lowered in situations of hypermetabolic metabolism and elevated in hypometabolic conditions, but remains constant in many pathologic states and can be used as a reliable reference value. With malignant tumors there are usually elevated choline concentrations, reflecting increased membrane synthesis and a higher cell turnover. The lactate level rises following a switch in metabolism from aerobic to anaerobic glycolysis, and this is frequently observed in the presence of malignant tumors. The occurrence of lipid peaks in a tumor spectrum suggests the presence of tissue necroses or metastases. There are typical constellations that are seen on MRS for individual tumors, which are discussed in detail in the present paper.

Modulation of circulating IGF-I and IGFBP-3 levels by hormonal regulators of energy homeostasis in obese children

Growth hormone (GH) and insulin-like growth factor-I (IGF-I) are key factors in the control of somatic growth. Recent work revealed a critical role for the transcription factor STAT5b in GH stimulated IGF-I gene expression. In obesity, the normal regulation of the GH/IGF-I axis is disturbed, with normal levels of circulating IGF-I despite blunted GH secretion. We hypothesized that leptin or other hormonal regulators of energy homeostasis, which can activate Stat5b-regulated gene expression or exert an effect on GH secretion, might be able to substitute for GH in terms of IGF-I synthesis. Thus, the aim of this study was to identify potential regulators of IGF-I serum levels in obesity with a particular focus on the interaction of leptin and IGF-I. In a cross-sectional study, we measured hormonal and auxiological parameters in 99 obese children who were referred to our obesity outpatient clinic and analysed correlations between unadjusted hormone levels and between hormone concentrations expressed as SDS values, adjusted for sex, age, and/or puberty and BMI. Serum concentrations of IGF-I correlated highly significant with IGFBP-3, leptin, fasting ghrelin and insulin (p<0.001). However, when expressing hormone levels as SDS values, only leptin SDS and IGFBP-3 SDS correlated significantly with IGF-I SDS (p<0.01). This correlation between leptin SDS and IGF-I SDS was more pronounced in prepubertal and in male subjects, with increasing IGF-I SDS values paralleling an increase in leptin SDS tertiles in prepubertal subjects. In linear regression analyses, leptin SDS, IGFBP-3 SDS and BMI SDS contributed significantly to the variation of IGF-I SDS values, and explained 53.3% of the variability of IGF-I SDS levels in male subjects.

SUMMARY AND CONCLUSIONS

In summary, we demonstrated a strong correlation of age and sex-adjusted standard deviation scores (SDS) for IGF-I and leptin in obese children, which is modulated by sex, pubertal stage and body weight. Whether this association results from a direct induction of hepatic IGF-I gene expression by leptin or reflects a more complex interrelationship between IGF-I and obesity-related factors should be subject of future research.

Urolithiasis beim kleinen Wiederkäuer – Behandlungsmethoden und klinische Rekonvaleszenz

Gegenstand und Ziel: Ermittlung der Prognose bei klinisch manifester Urolithiasis des kleinen Wiederkäuers in Abhängigkeit von der Behandlungsstrategie mit besonderem Augenmerk auf die Erfolgsraten zweier Methoden zur temporären Katheterzystostomie. Material und Methode: In einer retrospektiven Studie wurde das therapeutische Vorgehen an Schaf- und Ziegenböcken mit obstruktiver Urolithiasis hinsichtlich der Krankheitsverläufe zusammengefasst und evaluiert. Ergebnisse: Zwischen Januar 2000 und März 2006 wurden 27 Schaf- und 28 Ziegenböcke mit Urolithiasis vorgestellt. Bei 20% der Tiere erfolgte aus wirtschaftlichen Gründen auf Besitzerwunsch oder eines schlechten Allgemeinzustands die Euthanasie ohne Therapieversuch; 20% der Tiere wurden sofort durch eine Katheterzystostomie nach Laparotomie mit temporärer Implantation eines Ballonkatheters versorgt, wovon 57,1% als geheilt entlassen werden konnten. Bei 56,4% aller Patienten fand eine Therapie entsprechend einer Behandlungskaskade“ mit steigender Invasivität statt: Zunächst wurde der Processus urethrae abgesetzt. Bei 45,5% der so behandelten Tiere konnte der Harnfluss wieder hergestellt und die Heilung herbeigeführt werden. Bei 30,3% erfolgte eine chirurgische Versorgung zunächst durch transabdominale Zystostomie mittels Spaltkanüle und transkutaner Implantation eines Ballonkatheters unter Ultraschallkontrolle, die bei zwei Tieren erfolgreich war. Bei einem Bock schloss sich eine erfolgreiche Laparotomie mit erneuter temporärer Katheterzystostomie an, ein weiterer erfuhr eine erfolgreiche Urethrostomie. Die übrigen Tiere wurden wegen ihres schlechten Allgemeinzustandes und auf Besitzerwunsch oder aufgrund von Komplikationen euthanasiert oder verendeten. Schlussfolgerung und klinische Relevanz: Bei kleinen Wiederkäuern mit obstruktiver Urolithiasis bestanden die besten Heilungsaussichten, wenn der Harnfluss bereits durch Absetzen des Processus urethrae wieder hergestellt werden konnte. Gelang dies nicht, bildete die sofortige laparotomische Zystotomie mit temporärer Implantation eines Ballonkatheters die Methode mit dem größten Heilungserfolg. Die transabdominale Katheterzystostomie erwies sich gegenüber dem laparotomischen Vorgehen als unterlegen.

Urolithiasis bei einem Lamawallach

Gegenstand und Ziel: Die Zahl der in Deutschland gehaltenen Neuweltkameliden ist in den vergangenen Jahren angestiegen und bringt die praktischen Tierärzte in Kontakt mit neuem Patientengut. Ähnlich wie bei Wiederkäuern treten auch bei Neuweltkameliden männlichen Geschlechts Verlegungen der harnableitenden Wege auf. Der Artikel stellt den Fall eines achtjährigen Lamawallachs mit Urolithiasis dar. Material und Methoden: Die klinischen Symptome und Befunde sowie die Ergebnisse labordiagnostischer und pathomorphologischer Untersuchungen werden beschrieben, ferner die Resultate der Harnsteinanalyse sowie der Bestimmung des Silikatgehalts in Heu und Weidegras. Ergebnisse: Das Lama wies eine schwere Störung des Allgemeinbefindens auf. Die klinische Untersuchung und die Kreatinin- und Harnstoffwerte in Blut- und Bauchhöhlenflüssigkeit ergaben den Verdacht auf eine Urolithiasis mit Harnblasenruptur. Nach operativer Eröffnung der Bauchhöhle und Entleerung von mehr als 20 Litern gelblich blutiger Flüssigkeit sowie Darstellung der bereits rupturierten Harnblase wurde der Patient wegen infauster Prognose intraoperativ euthanasiert. Es folgte eine pathologisch-anatomische Untersuchung des Harnapparats. Blase und Niere wurden zusätzlich einer histopathologischen Begutachtung unterzogen. Auslösend für die Blasenruptur waren ein etwa 4 mm und zwei je 3 mm große Harnsteine aus Silikat, die zu einer Obstruktion der Urethra am Übergang vom Beckenteil in ihren Penisabschnitt geführt hatten. Das den Tieren diese Bestandes gefütterte Heu wies einen Silikatgehalt von 0,64% (bezogen auf die Trockensubstanz) auf. Die Silikatkonzentration im Grasaufwuchs der zur Verfügung stehenden Weidefläche betrug 1,82%. Schlussfolgerung und klinische Relevanz: Bei der Untersuchung männlicher Neuweltkameliden sollte bei unklarer Symptomatik und hochgradiger Störung des Allgemeinbefindens eine Urolithiasis in die differenzialdiagnostischen Überlegungen mit einbezogen werden. Trotz niedriger Silikatgehalte einheimischer Gräser können sich Urolithen auf Kieselsäurebasis entwickeln.

[Imaging of spinal tumors]

Spinal tumors are often categorized into extradural, intradural extramedullary, or intramedullary. Although this classification represents somewhat of an overgeneralization as a lesion may reside in two compartments, it still helps to characterize spinal tumors. In the intradural, extramedullary space, primary tumors, such as neurofibroma and meningioma, are relatively common. Secondary tumors or leptomeningeal enhancement also occur. In the intramedullary space, primary tumors are far more common than secondary tumors or metastases.

An experimental aneurysm model: a training model for neurointerventionalists

SUMMARY

Reproducible animal models not only facilitate the pre-clinical assessment of aneurysm therapy but can also help in training for interventional procedures. The objective of this study was to find an animal model that can be used to test different endovascular occlusion techniques. Aneurysms in the right common carotid artery were created in 35 NZW rabbits by distal ligation and intraluminal elastase infusion. A total of 27 aneurysms were occluded by endovascular embolization with GDC-Coils. The time needed for placement of the microcatheter into the aneurysm by a professional interventionalist, a semi-professional interventionalist and a trainee was measured. The percentage of occlusion (occlusion rate) of the aneurysms was determined angiographically after embolization and again three months later, followed by a histological examination. Aneurysms of 2-6 mm size were reliably created in all 35 animals; mean size was 3.0 mm in height and 5.5 mm in diameter. Occlusion was achieved in 27 animals. Five animals from the group of 35 were initially planned as a control group with no embolization. We added to the control group one animal whose aneurysm could not be occluded endovascularly because of partial thrombosis and small size of the aneurysm. The angiographically determined mean occlusion rate was 89.5% +/- 11.3% standard deviation. Histological evaluation of the six aneurysms of the control group showed that they remained patent. Aneurysms that underwent embolization showed organized thrombus formation with no signs of recanalization. Two animals died from anaesthesia related or embolic complications. The time needed by the professional did not significantly decrease, after a little practice the trainee was nearly as quick as the professional. The beginner showed extensive progress, reducing the time for catheter placement by more than 50%. This paper describes the angiographic and histopathologic findings and also demonstrates possible methods for training in interventional procedures. Animal models will play a vital part in the training of future interventionalists. This model has the capability of testing different embolization devices (GDC, Onyx(R))and methods. Histologic long-term prognosis and the physical effect of the coils can be evaluated with this model.

Sleep-wake disturbances in sporadic Creutzfeldt-Jakob disease

BACKGROUND

The prevalence and characteristics of sleep-wake disturbances in sporadic Creutzfeldt-Jakob disease (sCJD) are poorly understood.

METHODS

Seven consecutive patients with definite sCJD underwent a systematic assessment of sleep-wake disturbances, including clinical history, video-polysomnography, and actigraphy. Extent and distribution of neurodegeneration was estimated by brain autopsy in six patients. Western blot analyses enabling classification and quantification of the protease-resistant isoform of the prion protein, PrPSc, in thalamus and occipital cortex was available in four patients.

RESULTS

Sleep-wake symptoms were observed in all patients, and were prominent in four of them. All patients had severe sleep EEG abnormalities with loss of sleep spindles, very low sleep efficiency, and virtual absence of REM sleep. The correlation between different methods to assess sleep-wake functions (history, polysomnography, actigraphy, videography) was generally poor. Brain autopsy revealed prominent changes in cortical areas, but only mild changes in the thalamus. No mutation of the PRNP gene was found.

CONCLUSIONS

This study demonstrates in sporadic Creutzfeldt-Jakob disease, first, the existence of sleep-wake disturbances similar to those reported in fatal familial insomnia in the absence of prominent and isolated thalamic neuronal loss, and second, the need of a multimodal approach for the unambiguous assessment of sleep-wake functions in these patients.

In-patient versus in vitro degradation of P(L/DL)LA and PLGA

To assess and compare degradation rates, poly(70L-lactide-co-30DL-lactide) [P(L/DL)LA] and poly(85L-lactide-co-15-glycolide) (PLGA) copolymer degradation were studied in patients (maxillofacial region) and in vitro. Five patients of a total of 20 with 85:15 PLGA osteosyntheses, and 15 of a total of 60 with 70:30 P(L/DL)LA osteosyntheses, (10 females and 10 males, 26-55 years; mean, 33 years) underwent explantations after 3, 6, 9, 12, 18, and 24 months. Identical resorbables immersed in physiological buffer solution at 37 degrees C were compared at identical intervals. P(L/DL)LA's initial average molecular weight of 45,000 decreased to 25,000 in patients (and to 21,000 in vitro) after 6 months, and to 8000 in patients after 18 months. PLGA's average molecular weight decreased from 44,600 to 22,000 after 3 months in patients and in vitro, and to 11,000 in patients and 1300 in vitro at 6 months. In-patient and in vitro glass-transition temperatures decreased from approximately 60 degrees C to 50 degrees C over 18 months. Crystallinity in explants was < or = 4% in P(L/DL)LA throughout testing, and 16% and 30% in PLGA at 6 and 12 months, respectively. Both copolymers decomposed reliably in patients: 85:15 PLGA within 12 months and 70:30 P(L/DL)LA within 24 months on average (p < 0.005), leaving only extremely small granules that powder upon finger touch. In vitro rates were significantly faster (p < 0.005). Crystallinity associated with foreign-body reactions was minor and did not inhibit decomposition.

[Imaging of the temporal bone. An overview]

Diseases of the temporal bone should be diagnosed by high resolution computed tomography (CT) and magnetic resonance imaging (MRI). Because of the excellent imaging of bony structures, CT is the method of choice for diagnosing pathologies of the external auditory channel, middle ear, and mastoid. Imaging of trauma is performed with CT. For examining the labyrinth system and interior auditory channel, MRI is the method of choice. This article gives an overview of the anatomy of the temporal bone and describes the most important pathologies.

[Emergent pathogens, international surveillance and international health regulations (2005)]

In order to address the vitality of the microbial world, to detect emerging infectious diseases, to determine their potential threat to public health, and to establish effective interventions, the World Health Organization (WHO) has developed and coordinates the Global Outbreak Alert and Response Network (GOARN) which connects several surveillance networks. Some of these networks are specific to epidemic-prone diseases, such as influenza, dengue, yellow fever or meningitis. Others were especially designed to track unusual events--such as the emergence of SARS--that are naturally-occurring, accidental, or deliberately created (biological weapons, bio-terrorism). Lastly, a special effort is being made at the international level to modernize the International Health Regulations, now obsolete, and to support all the countries in the reinforcement of their outbreak alert and response capacity.

[Multiple Ebola virus haemorrhagic fever outbreaks in Gabon, from October 2001 to April 2002]

Outbreaks of Ebola virus haemorrhagic fever have been reported from 1994 to 1996 in the province of Ogooué Ivindo, a forest zone situated in the Northeast of Gabon. Each time, the great primates had been identified as the initial source of human infection. End of November 2001 a new alert came from this province, rapidly confirmed as a EVHV outbreak. The response was given by the Ministry of Health with the help of an international team under the aegis of WHO. An active monitoring system was implemented in the three districts hit by the epidemic (Zadié, Ivindo and Mpassa) to organize the detection of cases and their follow-up. A case definition has been set up, the suspected cases were isolated at hospital, at home or in lazarets and serological tests were performed. These tests consisted of the detection of antigen or specific IgG and the RT-PCR. A classification of cases was made according to the results of biological tests, clinical and epidemiological data. The contact subjects were kept watch over for 21 days. 65 cases were recorded among which 53 deaths. The first human case, a hunter died on the 28th of October 2001. The epidemic spreads over through family transmission and nosocomial contamination. Four distinct primary foci have been identified together with an isolated case situated in the South East of Gabon, 580 km away from the epicenter. Deaths happened within a delay of 6 days. The last death has been recorded on the 22nd of March 2002 and the end of the outbreak was declared on the 6th of May 2002. The epidemic spreads over the Gabon just next. Unexplained deaths of animals had been mentionned in the nearby forests as soon as August 2001: great primates and cephalophus. Samples taken from their carcasses confirmed a concomitant animal epidemic.

[Imaging cervical myelo- and radiculopathy]

PURPOSE

This article gives an overview of the diagnostic possibilities available in the diagnosis of cervical myelo- and radiculopathy. We compared conventional myelography, CTM, and MRI.

MATERIAL AND METHODS

Twenty-five patients with clinical evidence of cervical myelo- or radiculopathy were included. Sagittal and transverse T1-weighted (T1w) TSE and T2-weighted (T2w) TSE sequences were compared with myelography and CTM. Statistical analysis was performed using Wilcoxon's -test.

RESULTS

Disc herniation could be depicted in CTM as well as in MRI. The extent of herniation did not differ between CTM and T1w. The extent of herniation seemed higher on T2w than on T1w (p <0.001). Foraminal encroachment was easier to diagnose in CTM. When regarding transverse T1w and T2w images simultaneously, a missing root in MRI corresponded to a missing root in CTM and conventional myelography and vice versa. Our data demonstrated the relative inability of MRI to determine whether the compression is by soft tissue or bony structures.

CONCLUSION

The present study proposes that MRI, when available, should be the imaging method of first choice in patients with suspected radiculo- and myelopathy.

Die Moyamoya-Erkrankung

Moyamoya disease is an idiopathic progressive vasculopathy characterized by slowly progressive narrowing involving the distal internal carotid artery and the proximal circle of Willis. Collateral vessels develop to compensate for the slowly progressive stenosis. These enlarged collaterals appear as a "puff of smoke" on angiography, which gives the disease its name. This review discusses the clinical manifestation, imaging findings, and angiographic features.

Thrombolyse der A. basilaris: Ergebnisse im Saarland über einen Zeitraum von 5 Jahren

Acute thrombosis of the basilar artery has a fatal outcome if left untreated. The relatively good prognosis with intra-arterial thrombolysis makes it the therapy of choice for acute basilar thrombosis. In the Saarland stroke registry, we analyzed 47 patients with angiographically proven basilar artery thrombosis within the last 5 years. We observed a better outcome in patients with good income, with recanalization, and a short time between onset of symptoms and start of thrombolysis. The complications, such as intracerebral bleedings, occurred only in the group treated with rt-PA. Intra-arterial thrombolysis with urokinase or rt-PA is a relatively safe therapy, but should be performed in neuroradiological centers. With progressing symptoms the therapeutic window can be stretched up to 12 h, but coma lasting for more than 4 h is related to a bad outcome.

[Spinal intradural tumors]

Spinal intradural tumors are uncommon lesions but may cause significant morbidity. In establishing the differential diagnosis for a spinal lesion, location, age, and the patient's clinical presentation are important. Magnetic resonance imaging plays a central role in the visualization of spinal tumors, easily allowing tumors to be classified as extradural, intradural extramedullary, or intramedullary which is very useful in tumor characterization. We describe intradural tumors; the majority is extramedullary, with nerve sheath tumors being the most frequent. Intramedullary tumors are uncommon spinal tumors. Ependymomas and astrocytomas comprise the majority of this group. Typical imaging features of both intradural extramedullary and intramedullary tumors are described.

Role-playing for more realistic technical skills training

Clinical skills are an important and necessary part of clinical competence. Simulation plays an important role in many fields of medical education. Although role-playing is common in communication training, there are no reports about the use of student role-plays in the training of technical clinical skills. This article describes an educational intervention with analysis of pre- and post-intervention self-selected student survey evaluations. After one term of skills training, a thorough evaluation showed that the skills-lab training did not seem very realistic nor was it very demanding for trainees. To create a more realistic training situation and to enhance students' involvement, case studies and role-plays with defined roles for students (i.e. intern, senior consultant) were introduced into half of the sessions. Results of the evaluation in the second term showed that sessions with role-playing were rated significantly higher than sessions without role-playing.

Behandlung der arteriosklerotischen Karotisstenose: ein �berblick

Endarterectomy for extracranial carotid stenosis has proven to be the method of choice for symptomatic patients suffering from ischemia (NASCET, ECST). The effectivity of the operation for asymptomatic stenosis seems to be likely since the publication of the first results of the ACST trial. The safety and efficiency of carotid stenting has not been proven so far and has to be evaluated in randomized trials comparing surgery and endovascular treatment. We provide an overview of the current trials and try to define the role of carotid stenting.

Proximale Protektionssysteme beim Karotisstent

Controversies as to whether or not a protection device should be used in carotid artery stenting exist. Currently three temporary cerebral protection devices are being used. These are devices with distal balloon occlusion or filtration baskets and proximal occlusion devices with flow reversal in the internal carotid artery. This article focuses on flow reversal systems and aims to give some advice as to which patients could benefit from their use.

Adiponectin before and after weight loss in obese children

Adiponectin is decreased in obesity and seems to be involved in insulin resistance. The influences of age, gender, puberty, and weight loss on adiponectin have not been studied in obese children. We measured body fat mass based on skinfold thickness, age, pubertal stage, gender, adiponectin, and insulin resistance (homeostasis model assessment) in 42 obese children. We analyzed adiponectin and homeostasis model assessment 1 yr later in these obese children and separated them into two groups according to degree of weight loss (decrease in sd score for body mass index, >or=0.5 vs. <0.5). Adiponectin was negatively correlated to percentage body fat (r = -0.44; P = 0.002), insulin resistance (r = -0.33; P = 0.016), and age (r = -0.41; P = 0.003). Adiponectin levels were significantly (P = 0.017) higher in pubertal girls compared with boys, but there was no significant difference in prepubertal children in respect to gender (P = 0.833). Adiponectin was significantly (P < 0.001) lower in pubertal compared with prepubertal children. The significant weight loss in 16 children was associated with a significant increase in adiponectin (P = 0.010) and a decrease in insulin resistance (P = 0.013), whereas there were no changes in the 26 children without significant weight loss. Adiponectin levels in obese children were negatively correlated to age, body fat, and insulin resistance and were decreased in puberty. Significant weight loss led to an increase in adiponectin levels and an improvement of insulin resistance.

A laboratory model to evaluate cutout resistance of implants for pertrochanteric fracture fixation

OBJECTIVES

To establish a laboratory model of implant cutout, which can evaluate the effect of implant design on cutout resistance in a clinically realistic "worst case" scenario.

SETTING

Orthopaedic biomechanics laboratory.

DESIGN

Implant cutout was simulated in an unstable pertrochanteric fracture model, which accounted for dynamic loading, osteoporotic bone, and a defined implant offset. For model characterization, lag screw cutout was simulated in human cadaveric specimens and in polyurethane foam surrogates. Subsequently, foam surrogates were used to determine differences in cutout resistance between 2 common lag screws (dynamic hip screw, Gamma) and 2 novel blade-type implant designs (dynamic helical hip system, trochanteric fixation nail).

MAIN OUTCOME MEASURES

Implant migration was continuously recorded with a spatial motion tracking system as a function of the applied loading cycles. In addition, the total number of loading cycles to cutout failure was determined for specific load amplitudes.

RESULTS

Implant migration in polyurethane surrogates closely correlated with that in cadaveric specimens, but yielded higher reproducibility and consistent cutout failure. The cutout model was able to delineate significant differences in cutout resistance between specific implant designs. At any of 4 load amplitudes (0.8 kN, 1.0 kN, 1.2 kN, 1.4 kN) dynamic hip screw lag screws failed earliest. The gamma nail lag screw could sustain significantly more loading cycles than the dynamic hip screw. Of all implants, trochanteric fixation nail implants demonstrated the highest cutout resistance.

CONCLUSIONS

Implant design can significantly affect the fixation strength and cutout resistance of implants for pertrochanteric fracture fixation. The novel cutout model can predict differences in cutout resistance between distinct implant designs.