Biomedical subjects

T Müller

Publications and source records attributed to T Müller.

At least 37 records · Page 2Linked to original sources

PubMed2005

Electrical readout of the local nuclear polarization in the quantum Hall effect: a hyperfine battery.

It is demonstrated that the now well-established "flip-flop" mechanism of spin exchange between electrons and nuclei in the quantum Hall effect can be reversed. We use a sample geometry which utilizes separately contacted edge states to establish a local nuclear spin polarization--close to the maximum value achievable--by driving a current between electron states of different spin orientation. When the externally applied current is switched off, the sample exhibits an output voltage of up to a few tenths of a mV, which decays with a time constant typical for the nuclear spin relaxation. The surprising fact that a sample with a local nuclear spin polarization can act as a source of energy and that this energy is well above the nuclear Zeeman splitting is explained by a simple model which takes into account the effect of a local Overhauser shift on the edge state reconstruction.

Journal Article↗

PubMed2005

Trapping, deformation, and rotation of giant unilamellar vesicles in octode dielectrophoretic field cages.

The behavior of freestanding lipid bilayer membranes under the influence of dielectric force potentials was studied by trapping, holding, and rotating individual giant unilamellar vesicles (GUVs) inside dielectrophoretic microfield cages. Using laser scanning confocal microscopy and three-dimensional image reconstructions of GUVs labeled with fluorescent membrane probes, field strength and frequency-dependent vesicle deformations were observed which are explained by calculations of the dielectric force potentials inside the cage. Dynamical membrane properties under the influence of the field cage were studied by fluorescence correlation spectroscopy, circumventing potential artifacts associated with measurements involving GUV immobilization on support surfaces. Lipid transport could be accelerated markedly by the applied fields, aided by hydrodynamic fluid streaming which was also studied by fluorescence correlation spectroscopy.

Biophysics↗

PubMed2005

[Segmental dysfunction of sweating in multiple system atrophy].

There are many different causes of anhidrosis. Sweat glands can be absent, atrophic or blocked; sympathetic innervation may be disturbed, or central nervous system damage may prevent perspiration. We present a patient with multiple system atrophy ( MSA) who presented with unilateral anhidrosis of the trunk. MSA is a sporadic neurodegenerative disorder of adults involving the pyramidal, extrapyramidal, cerebellar and/or autonomic system. The findings in our patient could be explained by a depletion of catecholaminergic sympathetic neurons of the thoracic spinal neurons.

Barbiturates↗

PubMed2005

Dilated cardiomyopathy may be an early sign of the C826A Fukutin-related protein mutation.

Limb-girdle muscular dystrophy LGMD2I is caused by mutations in the fukutin-related protein (FKRP) gene. Clinically, LGMD2I exhibits a great phenotypic variability ranging from severe, rapidly progressive weakness and wasting of the limb-girdle muscles to mild disorders. Here, we present three siblings without clinical signs of muscle dystrophy, but with dilated cardiomyopathy. Elevated serum creatine kinase level and partial fatty degeneration of muscles on MRI indicated subclinical involvement of skeletal muscles. The patients were homozygous for the common C826A mutation in the FKRP gene. Although cardiac involvement in patients with clinically typical LGMD2I was previously described, no patient with dilated cardiomyopathy as the only clinical manifestation of the FKRP mutation was reported so far.

Adult↗

PubMed2005

Use of micro-rotation imaging to study JNK-mediated cell survival in Theileria parva-infected B-lymphocytes.

Lymphocytes infected with the protozoan parasite Theileria parva are transformed to permanently proliferating cells, an event underlying the pathology of the disease. However, the molecular signalling mediating this process is complex and poorly understood. Here, we show that down-regulation of JNK signalling by transient over expression of a dominant-negative mutant of JNK (JNK-APF) significantly increases Annexin-V-phycoerythrin (V-PE) labelling on infected B cell populations observed using flow cytometry. To establish whether this increase was specifically due to apoptosis, we used a novel single-cell imaging method: micro-rotation (MR)-imaging, designed to allow high-resolution 3-dimensional imaging of single cells in suspension. With this method we visualized subcellular patterns of V-PE uptake and chromatin organization in lymphocytes co-transfected with JNK-APF and GFP-tagged histone-H2B. This single-cell approach allowed us to clearly reveal characteristic apoptotic phenotypes, whose patterns reflected progressive states of programmed cell death due to JNK down-regulation. Our results strongly suggest a role for JNK in the survival of Theileria-infected B cells, and demonstrate the powerful utility of a new and unique 3-dimensional imaging method for living cells in suspension.

Animals↗

PubMed2005

[The use of a thermomechanical cleaning procedure for removal of residual particles of corund blasted or glass bead peened implants in total hip arthoplasty].

INTRODUCTION: Shot peening and grit blasting techniques are used to modify surfaces of hip endoprostheses. Alumina blasting techniques using highly pure corund (Al (2)O (3)) particles create a rough surface of Titanium implants to achieve a better osteointegration in cementless total hip arthroplasty. An increasing number of publications in maxillo-facial-surgery and orthopedic surgery show that there is a significant contamination with remnants on corund blasted surfaces. To our knowledge no previous study analysed the effects of cleaning procedures of hip endoprostheses in respect to glass beads and Al (2)O (3) remnants. MATERIAL AND METHOD: The surface of the flexible anisotropic Vector cup and the stiff modular MRP-Titan stem (one implant each) were analysed with respect to Al (2)O (3) or glass particles before and after the cleaning procedure. The implants were cleaned using an ultrasound bath for 10 or 20 minutes under nitrogen cooling or simple ultrasound bath with water. A field emission scanning electron microscopy (LEO 1525) was used for the detection of the particles on the implant surface with a backscattered electron detector. The proportion of the surface covered with particles was determined with an imaging analyze software (analySIS, Soft Imaging System GmbH). RESULTS: A reduction of corund particles on the surface of the flexible anisotropic Vector cup of up to 5.2 % (from 40.0 % to 34.8 %) after 10 minutes nitrogen cooling was achieved. A reduction of corund particles on the surface of the stiff MRP-Titan stem of up to 2.2 % (from 38.8 % to 36.6 %) was observed after 20 minutes of non cooled ultrasound bath whereas a reduction up to 3.2 % (from 25.8 % to 22.6 %) of glass particles after 10 minutes of nitrogen cooled ultrasound bath was detected. CONCLUSION: With the cleaning procedure tested only incomplete removal of just the small glass and Al (2)O (3) particles is possible. Further research is needed to reduce or even avoid residual particles in total hip arthoplasty.

Arthroplasty, Replacement, Hip↗

PubMed2005

Long-term studies on maternal immunity for Aujeszky's disease and classical swine fever in wild boar piglets.

The aim of the studies was to fathom the duration and the role of maternal immunity for Aujeszky's disease (AD) and classical swine fever (CSF) in wild boar offspring. In one experiment, two wild boar sows were infected with a low pathogenic pseudorabies virus (PRV) in 1999. A total of 51 offspring was born between 1999 and 2002 and was monitored for PRV maternal antibodies. In a second experiment, the maternal immunity for CSF was analysed. Therefore, a sow was orally vaccinated against CSF using vaccine baits containing the live-attenuated C-strain vaccine. The vaccination took place in January 1999. The sow gave birth to four piglets in 2001 and to two piglets in 2002. With respect to maternal immunity for AD, some piglets reacted positive in the ELISA up to 27-week post-partum while in the neutralization test antibodies were detected up to 15-week post-partum. The calculated half-life of neutralizing antibodies was 21 days. Regarding CSF, the neutralization titres of maternal antibodies dropped continuously reaching values of < or =10 ND50 20-week post-partum. After the 12th week post-partum, most of the sera reacted negative in the ELISA. However, after the third month, low levels of neutralization titres were still detectable. The results are discussed with respect to the epidemiology and control of both diseases in wild boar populations.

Animals↗

PubMed2005

The testis histology of artificially maturated European eel (Anguilla anguilla L.) at the end of sexual maturation, and spermatozoa ultrastructure in freshwater rearing. Short communication.

The artificial induction of sexual maturation of European eel males was carried out by using weekly hCG administrations. Histological pictures showed that the testis tissues developed and regressed naturally and no pathological changes took place under the conditions of artificial rearing in freshwater. According to light and electron microscopic investigations the morphology and motility of the spermatozoa of males kept in freshwater proved to be similar to those in seawater. The authors suppose that freshwater rearing of males is not a barrier factor in the artificial propagation of European eels.

Anguilla↗

PubMed2005

Cryopreservation of European eel (Anguilla anguilla) sperm using different extenders and cryoprotectants. Short communication.

Experiments were carried out on the sperm cryopreservation of artificially induced eels. The effects of several extenders and two cryoprotectants on the motility of spermatozoa were investigated. The highest post-thaw motility was observed with the combination of Tanaka's extender and DMSO as cryoprotectant. Further dilution after thawing resulted in complete loss of motility in samples frozen in presence of DMSO while sperm frozen with methanol as cryoprotectant retained its motility after further dilution.

Anguilla↗

PubMed2005

[Proposal for changing the spot checking examination regarding the control of the maintenance of freedom from Aujeszky's disease (AD)].

In Germany the last outbreak of Aujeszky's disease (AD) in a holding of domestic pigs had been officially confirmed in the year 2000, and, since February 2003 Germany is officially confirmed free of AD. Since this time the AD free status is monitored according to chapter II of the annex of the regulation for the protection against Aujeszky's disease. As an alternative monitoring protocol two variants of a two step random sampling scheme is proposed which reduces the sample size from a complete investigation of all domestic pig holdings to a sample of pig fattening and pig breeding farms. Within the random selected farms, pigs are sampled as usual according to chapter II of the annex of the regulation for the protection against Aujeszky's disease. In this paper, the measures to be taken in case of a positive AD result are discussed: In case of conformation of an AD suspicion it is proposed to establish a restriction area. In addition measures based on regionalisation are proposed in order to maintain the AD free status for areas outside established restriction areas. The proposed monitoring schemes potentiate an enormous reduction of sampling costs, but call for a revision of the regulation for the protection against Aujeszky's disease.

Animals↗

PubMed2005

Quantification of tension in Thera-Band and Cando tubing at different strains and starting lengths.

AIM: Elastic resistance exercise is frequently used in rehabilitation programs. Precise quantification using color coded bands is not possible. A method to predict forces for any length of mostly used elastic tubings and thereby a general equation for the comparison of elastic material is presented. METHODS: In an in vitro-series the tubing tension in relation to elongation of 6 colors of Thera-Band and Cando tubings was directly measured. The relation between tension and elongation was determined depending on different resting lengths. In clinical practice tension and elongation are prescribed. Two mathematical methods to calculate the resting length as regulatory variable are presented. One is based on the construction of iso-tension curves, the 2nd on the general mathematical relation delta % tension=K* % length change+n. RESULTS: 1. The tension/elongation relation is linear beyond a threshold in the early part of elongation. 2. The iso-tension method works graphically and facilitates the precise determination of resting length. 3. The double % relation between tension and elongation method describes the general properties of all tubings, where K=0.75 is a general constant. To calculate absolute values for the resting length, corresponding to a given tension and elongation, special ''color constants'' are presented. CONCLUSIONS: The prediction of maximum tension values for any given elongation is possible by simple variation of resting length. These findings may improve the usefulness of elastic tubings in rehabilitation programs. The mathematical method further may be used for the comparison of elastic materials with linear characteristics.

Algorithms↗

PubMed2005

Fox rabies in Germany - an update.

In comparison with conventional methods of wildlife rabies control, oral rabies vaccination of foxes (ORV) is without doubt the most (cost-) effective method in wildlife rabies control. As a result of ORV, several European countries have become rabies-free. Although rabies had been eliminated from much of Germany, there still exists a residual rabies focus in the border triangle of Hesse, Baden-Wurttemberg and Rhineland Palatinate. Corrective actions have been initiated to eliminate this last remaining rabies hotspot in Germany.

Administration, Oral↗

PubMed2004

Efficacy of budipine and placebo in untreated patients with Parkinson's disease.

Previous studies demonstrated the efficacy of budipine on motor symptoms of treated patients with Parkinson's disease (PD) with rating scales. However rating procedures may be subjective and variable. Therefore additional use of instrumental motor tests are helpful to reflect therapeutic benefits. Objective was to test the efficacy of 20 mg budipine (t.i.d.) in 51 previously untreated idiopathic PD patients in a monocenter, double-blind, placebo-controlled trial with a 2:1 randomisation over a three month interval. Budipine was not superior to placebo application. However a detailed analysis of rating results shows, that budipine but not placebo treated patients significantly improved. Budipine caused significant better outcomes of motor tests with execution of complex movements, but did not change results of tasks, which demand for simple motions. Placebo significantly improved dopamine sensitive motor test results. These outcomes may result from improved non dopaminergic neurotransmission due to budipine. Placebo caused better results of dopamine sensitive tests, since placebo may release endogenous dopamine.

Adult↗

PubMed2004

Experimental investigation of early-time diffusion in the quantum kicked rotor using a Bose-Einstein condensate.

We report measurements of the early-time momentum diffusion for the atom-optical delta-kicked rotor. In this experiment a Bose-Einstein condensate provides a source of ultracold atoms with an ultranarrow initial momentum distribution, which is then subjected to periodic pulses (or "kicks") using an intense far-detuned optical standing wave. We characterize the effect of varying the effective Planck's constant for the system, while keeping all other parameters fixed. The observed behavior includes both quantum resonances (ballistic energy growth) and antiresonances (re-establishment of the initial state). Our experimental results are compared with theoretical predictions.

Journal Article↗

PubMed2004

Central venous catheters--the inability of 'intra-atrial ECG' to prove adequate positioning.

BACKGROUND: The classic increase in P wave size, known as 'P-atriale', is a widely accepted criterion for determination of proper positioning of central venous catheter tips. Recent transoesophageal echocardiography (TOE) studies did not confirm intra-atrial position despite advancing the central venous catheter further than indicated by ECG guidance. We postulate that the pericardial reflection rather than the entry into the right atrium corresponds to the ECG changes. In order to test our hypothesis we sought to determine the anatomical substrate for the electrical changes in an animal study. Subsequently, a modified version of the study was undertaken in man and is also reported. METHODS: In six juvenile pigs the left external jugular vein and right carotid artery were cannulated. A triple-lumen central venous catheter was positioned by ECG guidance using a Seldinger wire as an exploring electrode. The venous and arterial catheters were suture fixed 2 cm beyond the onset of an increase in P wave size. The corresponding anatomical catheter tip position was determined by open exploration of the vessels and the heart. Subsequently the catheter tip position (during advancement) of a pulmonary artery catheter and the corresponding electrical ECG changes were examined in 10 patients during open chest cardiac surgery. RESULTS: All catheters-arterial and venous, in animals and humans-revealed an increase in size of the P wave as well as the QRS complex. All venous catheters were positioned in the superior vena cava, beyond the pericardial reflection but outside the right atrium. All arterial catheters were positioned in the ascending aorta thus also beyond the pericardial reflection. CONCLUSIONS: The start of an increase in P wave size does not correspond with the entrance of the right atrium. The anatomic equivalent for the electrophysiological changes of the ECG is the pericardial reflection. ECG guidance is unable to distinguish between venous and arterial catheter position.

Aged↗

PubMed2004

Randomized phase III study of gemcitabine and vinorelbine versus gemcitabine, vinorelbine, and cisplatin in the treatment of advanced non-small-cell lung cancer: from the German and Swiss Lung Cancer Study Group.

PURPOSE: To evaluate whether cisplatin-based chemotherapy (gemcitabine, vinorelbine, and cisplatin [GVP]) prolongs overall survival in comparison to cisplatin-free chemotherapy (gemcitabine and vinorelbine [GV]) as first-line treatment in patients with advanced non-small-cell lung cancer (NSCLC). PATIENTS AND METHODS: Between September 1999 and June 2001, 300 patients with NSCLC stage IIIB with malignant pleural effusion or stage IV disease were randomly assigned to receive GV (gemcitabine 1000 mg/m(2) + vinorelbine 25 mg/m(2) on days 1 and 8 every 3 weeks) or GVP (gemcitabine 1000 mg/m(2) + vinorelbine 25 mg/m(2) on days 1 and 8 + cisplatin 75 mg/m(2) on day 2 every 3 weeks). Primary end point of the study was overall survival. RESULTS: Two hundred eighty-seven patients (GV, 143 patients; GVP, 144 patients) were eligible for analysis. At the time of analysis, April 15, 2002, 209 patients (GV, 103 patients; GVP, 106 patients) of 287 patients had died (73%). No statistically significant difference was observed for overall survival (P =.73; median survival, 35.9 versus 32.4 weeks; 1-year survival rate, 33.6% versus 27.5%) as well as for event-free survival (P =.35; median time-to-event, 19.3 versus 22.3 weeks) between GV and GVP. Two hundred fourteen patients were assessable for best response. The overall response rates were 13.0% for GV versus 28.3% for GVP (P =.004; complete responders, 0% versus 3.8%; partial responders, 13.0% versus 24.5%). Hematologic and nonhematologic toxicity was significantly lower in the GV treatment arm compared with GVP. No statistically significant difference in quality of life was observed. CONCLUSION: In this phase III study, the cisplatin-based GVP regimen showed no survival benefit as first-line chemotherapy in advanced NSCLC when compared with the cisplatin-free GV regimen, which was substantially better tolerated.

Adolescent↗

PubMed2004

Stroke following variceal sclerotherapy.

OBJECTIVE: Paradoxical embolism via a patent foramen ovale (PFO) has been identified as a potential risk factor for ischaemic stroke. Such occurrences are associated with risk factors for deep vein thrombosis (DVT), e. g. pregnancy, immobilisation, and surgery of the lower limbs. OBSERVATION: A 54-year-old otherwise healthy female presented with acute onset motoric aphasia and brachiofacial right hemiparesis. The cranial computed tomography showed a left striatal ischaemic infarction. The patient's history revealed a variceal sclerotherapy with polydocanol 0,5% three days prior to the onset of symptoms. Echovist TCM doppler revealed a right-to-left shunt. A patent foramen ovale (PFO) was detected by transesophageal echocardiography. There was no evidence of DVT in bilateral lower-extremity venous duplex ultrasound scanning. Other potential risk factors of stroke including thrombophilia could not be identified. The patient was treated with a high dose regimen of heparin and a further anticoagulation treatment was recommended. CONCLUSION: This case suggests a probable causal relationship between variceal sclerotherapy and paradoxical embolism resulting in a stroke. Variceal sclerotherapy might be a potential, but rare risk of embolism.

Brain Ischemia↗

PubMed2004

Antiapoptotic effects of budipine.

Apoptosis is one essential step for neuronal death in the nigrostriatal region in patients with Parkinson's disease. Cytotoxic tumor necrosis factor-alpha (TNF-alpha) and the proinflammatory cytokine interleukin-6 (Il-6) provide a proapoptotic environment. We investigated the influence of the antiparkinsonian compound budipine on the release of TNF-alpha and Il-6 in peripheral blood mononuclear cells (PBMC) and on the degree of cisplatin induced apoptotic cell death in SH-SY 5Y human neuroblastoma cells. 10(-7), 10(-8), 10(-9) mol/l of budipine significantly reduced release of TNF-alpha and Il-6 in PBMC and decreased apoptotic cell death after 50 hours and 74 hours in the SH-SY 5Y cells. Our results suggest, that budipine administration provides an antiapoptotic environment and slows neuronal apoptotic and inflammatory mediated loss of neurons.

Anti-Inflammatory Agents, Non-Steroidal↗