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.     

Variations of skin biophysical properties after recreational swimming

Background/purpose: Sensations of itching and skin tightness are frequently reported after recreational swimming in pool water. Our objective was to measure the potential changes occurring at the skin surface under such conditions.
Methods: Nine women participated in this study, which consisted of two periods. During a 4-day control period, basal biophysical skin parameters were assessed every morning. On the first day, measurements were also performed in the afternoon. The second study period followed the same study design as for the control period, except that, on the first day, women swam for 1 h in a public pool, between the measurements performed in the morning and the afternoon. Skin capacitance, transepidermal water loss, skin temperature, skin pH and sebum casual level (SCL) were measured on facial and body sites.
Results: During the control period, biophysical skin parameters did not show significant variations. By contrast,      h after swimming, biophysical values showed significant changes for all test sites: skin pH increased, whereas skin capacitance and SCL decreased. Biophysical parameters returned to baseline values the day after swimming.
Conclusion: Our results demonstrate that recreational swimming leads to significant transient changes in skin surface properties of women with healthy skin.     

Variability in eating behavior throughout the weaning period

During the introduction of solid food (usually indicated as the weaning period), infant and caregiver have to adjust their feeding interactions to a completely changed feeding context. In this paper, we argue that these adjustments can be seen as a complex process in which many factors are involved. As a result of these complex interactions, eating behavior can be highly variable between infants and from feed to feed. The aim of this study is to describe these patterns of variability across this critical transition in feeding. The study is based on naturalistic observations of 20 infant–caregiver dyads (15 repeated observations of each dyad), from the first attempt to spoon-feed till 12 weeks after the introduction of solid food. The results show that there is considerable short-term variability in eating behavior (food intake, meal duration, feeding efficiency, and food refusal), especially immediately after the introduction of solid food. The largest intra-individual variability was found in the earliest feeding sessions, which is consistent with the proposition that systems that undergo rapid development are most sensitive to context variables and thus most variable.     

Magnetic resonance microimaging for noninvasive quantification of myocardial function and mass in the mouse

The purpose of this work was to develop high-resolution cardiac magnetic resonance imaging techniques for the in vivo mouse model for quantification of myocardial function and mass. Eight male mice were investigated on a 7-Tesla MRI scanner. High-quality images in multiple short axis slices (in-plane resolution 117 μm², slice thickness 1 mm) were acquired with an ECG-gated cine sequence. Left ventricular end-diastolic and end-systolic volumes and mass were calculated from segmented slice volumes. There was precise agreement of left ventricular mass determined ex vivo and by MRI. lntraobserver (5%) and interobserver (5%) variability of in vivo MR measurements were low.     

Gene expression in bipolar disorder and schizophrenia: new approaches to old problems

Bahn S. Gene expression in bipolar disorder and schizophrenia: new approaches to old problems. Bipolar Disord 2002: 4(Suppl. 1): 70–72. © Blackwell Munksgaard, 2002