Continuous bone morphogenetic protein-2 gradients for concentration effect studies on C2C12 osteogenic fate

Cells can respond to small changes in a varying concentration of exogenous signaling molecules. Here we propose the use of continuous surface chemical gradients for the in-depth study of dose-dependent effects on cells. A continuous surface gradient of bone morphogenetic protein-2 (BMP-2) is presented. The gradient covers a narrow range of surface densities (from 1.4 to 2.3 pmol/cm²) with a shallow slope (0.9 pmol/cm³). These characteristics represent a quasi-homogeneous surface concentration at the cell scale, which is crucial for cell screening studies. Cell fate evaluation at early stages of osteogenesis in C2C12 cells, indicates the potential of continuous gradients for in vitro screening applications.From the Clinical EditorThe authors propose the use of surface-applied continuous chemical gradients for in-depth study of dose-dependent effects on cells. The method is demonstrated using BMP-2 proteins on C2C12 cells as a model system.     

Pelvimetry revisited: Analyzing cephalopelvic disproportion

The objective of this study was to assess the clinical value of pelvimetry to predict dystocia due to cephalopelvic disproportion.63 patients who had received an abdominal CT scan postpartum were included. Pelvimetry was performed retrospectively with these datasets on a 3D workstation; there were no CT examinations performed solely for pelvimetry, and there was no radiation exposure for study purposes. Patients were divided into three groups by the course of birth, i.e. normal vaginal delivery (A), dystocia due to cephalopelvic disproportion (B) and other patients (C). Previously described methods were evaluated for their accuracy in diagnosing cephalopelvic disproportion.The pelvimetric parameters did not show significant differences between groups A (n = 20) and B (n = 20) except for the sagittal mid-pelvic diameter (q) with 12.7 ± 0.6 cm vs. 11.9 ± 0.6 cm (p = 0.0001). The ROC analysis of the previously described methods showed areas under the curve between 0.50 and 0.67. The ROC curves for q had an area of 0.88, providing 85% sensitivity with 85% specificity.In conclusion, the sagittal mid-pelvic diameter shows potential to detect cephalopelvic disproportion with acceptable accuracy. With the information gained on the CT data, a prospective trial based on MR imaging can be set up to validate the diagnostic accuracy.     

Comparison of written reports of mammography, sonography and magnetic resonance mammography for preoperative evaluation of breast lesions, with special emphasis on magnetic resonance mammography

Patients with abnormal breast findings (n = 413) were examined by mammography, sonography and magnetic resonance (MR) mammography; 185 invasive cancers, 38 carcinoma in situ and 254 benign tumours were confirmed histologically. Sensitivity for mammography was 83.7%, for sonography it was 89.1% and for MR mammography it was 94.6% for invasive cancers. In 42 patients with multifocal invasive cancers, multifocality had been detected by mammography and sonography in 26.2%, and by MR mammography in 66.7%. In nine patients with multicentric cancers, detection rates were 55.5, 55.5 and 88.8%, respectively. Carcinoma in situ was diagnosed by mammography in 78.9% and by MR mammography in 68.4% of patients. Combination of all three diagnostic methods lead to the best results for detection of invasive cancer and multifocal disease. However, sensitivity of mammography and sonography combined was identical to that of MR mammography (ie 94.6%).     

Proteins involved in synaptic vesicle trafficking

Neurotransmitter release relies on a series of synaptic vesicle trafficking reactions. We have determined the molecular basis of these reactions by microinjecting, into 'giant' nerve terminals of squid, probes that interfere with presynaptic proteins. These probes affect neurotransmitter release and disrupt nerve terminal structure. From the nature of these lesions, it is possible to deduce the roles of individual proteins in specific vesicle trafficking reactions. This approach has revealed the function of more than a dozen presynaptic proteins and we hypothesize that neurotransmitter release requires the coordinated action of perhaps 50–100 proteins.     

Analysis of the pre-incident education and subsequent performance of emergency medical responders to the Volendam café fire.

OBJECTIVE: At this moment, in the Netherlands, rescue workers are not given any specific standardized training in disaster response or disaster management.After the café fire in Volendam, the Netherlands, on New Year's Eve 2000, around 200 rescue workers were deployed on-site. The aim of this study is to investigate the rescue workers' experiences with regard to their level of preparation for the emergency response. METHODS: In 2002, 30 members of the medical and paramedical personnel were requested to participate in a structured interview, focused on education, task perception, triage and registration. RESULTS: Twenty-seven participated. Twenty-two rescue workers received previous training in emergency medicine. During the alarm phase, 11 rescue workers had a clear perception of their tasks. Twenty-four were involved in triage and injury assessment. Three rescue workers used a protocol for triage and 15 for injury assessment. Twenty-five rescue workers gave on-scene treatment and 15 used a protocol. Eight registered their findings. CONCLUSIONS: Preparation for the emergency response lacked standardized procedures. The use of triage protocols was extremely poor, as was documentation of actions. Slightly more than half of the personnel followed treatment protocols. It is advisable that all rescue workers become familiar with the basic uniform principles and protocols regarding disaster management. A dedicated and standardized national disaster management course is needed for all rescue workers.     

Magnetresonanztomographie von Stents: Quantitative MR-Untersuchungen in vitro bei 3 Tesla

PurposeThe aim of this study was to qualitatively and quantitatively study MR artifacts of various stents on the basis of in vitro experiments. We were particularly interested whether sequence type and orientation of the stent with respect to the static magnetic field influences the artifact.Material and MethodsWe examined 18 stents of different material (nitinol, stainless steel, cobalt alloy), different design of the stent meshes (AccuLink, OmniLink, DynaLink, Xact, Protoge, Wallstent Monorail), different diameter (5–10 mm) and different length (18–58 mm) with a turbo spin echo (TSE), a 2D-fast low angle shot (FLASH) and a 3D-FLASH sequence. The MR images were examined qualitatively with respect to possible artifacts. Furthermore we examined the MR data quantitatively: The contrast-noise-ratio (CNR) was determined both within the stent and outside (within the tube); based on these values we calculated the transparency factor P, furthermore we calculated the apparent vascular lumen within the tube and within the stent.ResultsThe stents made of stainless steel and cobalt alloy displayed severe susceptibility artifacts. Therefore the vessel lumen within the stent could not be assessed. The nitinol stents showed different artifact patterns: The AccuLink and DynaLink stents showed less artifacts compared to the Xact and Protoge stents. Besides the susceptibility artifacts we found artifacts due to RF shielding by the stent mesh, particularly in TSE sequences.ConclusionA MR control of patients after stenting is possible and may yield diagnostic information when using the AccuLink or DynaLink stents. However, it is important to make sure that the stent is MR safe for the field strength used for the examination.     

<Emphasis Type="Italic">CCM1</Emphasis> gene deletion identified by MLPA in cerebral cavernous malformation

Familial cerebral cavernous malformations (CCMs) occur with a frequency of 1 in 2000 and may cause recurrent headaches, seizures, and hemorrhagic stroke. Exon-scanning-based methods have identified intragenic mutations in three genes, CCM1, CCM2, and CCM3, in about 70% of familial CCM. To date, only two large CCM2 and a single large CCM3 deletion have been published. In addition to direct sequencing of all three CCM genes, we applied a newly developed multiplex ligation-dependent probe amplification gene dosage assay (MLPA) designed to detect genomic CCM1–3 deletions/duplications. Direct sequencing did not reveal a mutation in the index case who presented with multiple CCMs that had caused a generalized tonic-clonic seizure with Todd’s paralysis and headaches at the age of 5. In contrast, MLPA analyses detected a large deletion involving the entire CCM1 coding region in the proband and further affected members of this German CCM family. The MLPA results were corroborated by analyses of single nucleotide polymorphisms (SNPs) within the CCM1 gene. Thus, we here present the first report on a CCM1 gene deletion. Our results confirm a loss-of-function mutation mechanism for CCM1 and demonstrate that the use of MLPA enables a higher CCM mutation detection rate which is crucial for predictive testing of at-risk relatives.     

Tyramine-Containing Poly(4-Nitrophenylacrylate) as lodinatable Ligand Carrier in Biodistribution Analysis

Purpose. Targeted label or drug delivery requires access to convenient carrier systems and methods for efficient ligand conjugation. The main purpose of this study is to design an iodinatable synthetic polymer, whose application in vivo in tumor-bearing mice is tested with several related carbohydrate ligands, namely ABH and Lewis blood group epitopes. Methods. Tyramine and aminopropyl derivatives of the synthetic oligo-saccharides were attached to poly(4-nitrophenylacrylate). Following iodination, the biodistribution of the sugar-free and the substituted polymers was determined in tumor-bearing mice. Flow cytofluorimetric analysis assessed tumor cell binding of further ligand types to human tumor cells in vitro. Results. Quantitative ligand incorporation was achieved under mild conditions. Whereas the ligand-free poly[N-(2-hydroxyethyl)acrylamide] (MW 30 kDa) showed preferential accumulation in kidney, neoglycopolymers were found in substantial amounts in liver, kidney or spleen. The nature of the carbohydrate structure quantitatively influenced the distribution pattern. Tumor cell binding of blood group determinants and three further ligand types revealed non-uniform intensity in labeling and percentage of positive cells even in comparison between lines with identical histogenetic origin. Conclusions. Carbohydrate-exposing poly[N-(2-hydroxyethyl)acrylamide] polymers with tyramine as an iodine acceptor distribute in mice with a profile which is quantitatively influenced by small structural variations of the ligand part. Further refinement of the ligand structure may increase the level of selectivity for organ and tumor accumulation.