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M Fuchs

Publications and source records attributed to M Fuchs.

At least 37 records · Page 2Linked to original sources
PubMed2005

Photoproduction of eta mesons off protons for 0.75 GeV<E(gamma)<3 GeV.

Total and differential cross sections for the reaction p(gamma,eta)p have been measured for photon energies in the range from 750 MeV to 3 GeV. The low-energy data are dominated by the S11 wave which has two poles in the energy region below 2 GeV. Eleven nucleon resonances are observed in their decay into peta. At medium energies we find evidence for a new resonance N(2070)D15 with (M,Gamma)=(2068+/-22, 295+/-40) MeV. At gamma energies above 1.5 GeV, a strong peak in the forward direction develops, signaling the exchange of vector mesons in the t channel.

Journal Article↗
PubMed2005

Combining high-field EPR with site-directed spin labeling reveals unique information on proteins in action.

In the last decade, joint efforts of biologists, chemists and physicists have helped in understanding the dominant factors determining specificity and directionality of transmembrane transfer processes in proteins. In this endeavor, electron paramagnetic resonance (EPR) spectroscopy has played an important role. Characteristic examples of such determining factors are hydrogen-bonding patterns and polarity effects of the microenvironment of protein sites involved in the transfer process. These factors may undergo characteristic changes during the reaction and, thereby, control the efficiency of biological processes, e.g. light-induced electron and proton transfer across photosynthetic membranes or ion-channel formation of bacterial toxins. In case the transfer process does not involve stable or transient paramagnetic species or states, site-directed spin labeling with suitable nitroxide radicals still allows EPR techniques to be used for studying structure and conformational dynamics of the proteins in action. By combining site-directed spin labeling with high-field/high-frequency EPR, unique information on the proteins is revealed, which is complementary to that of X-ray crystallography, solid-state NMR, FRET, fast infrared and optical spectroscopic techniques. The main object of this publication is twofold: (i) to review our recent spin-label high-field EPR work on the bacteriorhodopsin light-driven proton pump from Halobacterium salinarium and the Colicin A ion-channel forming bacterial toxin produced in Escherichia coli, (ii) to report on novel high-field EPR experiments for probing site-specific pK(a) values in protein systems by means of pH-sensitive nitroxide spin labels. Taking advantage of the improved spectral and temporal resolution of high-field EPR at 95 GHz/3.4 T and 360 GHz/12.9 T, as compared to conventional X-band EPR (9.5 GHz/0.34 T), detailed information on the transient intermediates of the proteins in biological action is obtained. These intermediates can be observed and characterized while staying in their working states on biologically relevant timescales. The paper concludes with an outlook of ongoing high-field EPR experiments on site-specific protein mutants in our laboratories at FU Berlin and Osnabrück.

Bacteriorhodopsins↗
PubMed2005

Repair of meniscal tears with the absorbable Clearfix screw: results after 1-3 years.

INTRODUCTION: Total meniscus resection usually leads to osteoarthritis of the knee joint. Preservation and refixation of the injured menisci are therefore of great clinical importance. MATERIALS AND METHODS: The present study examines 40 meniscal injuries in 37 patients that were arthroscopically treated with Clearfix meniscal screws (Mitek, Norderstedt, Germany) in the period from August 1999 to December 2002. The mean patient age was 27.7 (range 16-62) years. Nine patients were female. A total of 24 patients (27 meniscal tears) also had an anterior cruciate ligament (ACL) lesion, and 5 patients had cartilage injuries. Twenty-two patients were treated within the first 2 weeks following the trauma, 10 patients within 8 weeks, and 5 patients after 8 weeks. The lesions were a bucket-handle tear of the medial meniscus in 11 cases and a bucket-handle tear of the lateral meniscus in 2 cases. The posterior horn of the medial meniscus was torn in 13 cases, and the pars intermedia in 3 cases. The posterior horn of the lateral meniscus was torn in 8 cases, and the pars intermedia in 3 cases. The mean tear length was 2.9 (+/- 1.5) cm and was fixed with an average of 1.8 (+/- 0.7) screws. In 7 cases, the anterior horn was treated with an additional meniscal suture. A total of 35 patients were examined after an average of 18 (range 7-45) months. RESULTS: In the event of a moderate outcome, MRI was performed as part of the follow-up investigation. The average Lysholm score was 93 (+/- 7.4), the Tegner activity index was 6.3 (+/- 2.0) before the accident and 5.8 (+/- 2.0) at the follow-up, the Marshall knee score was 47 (+/- 3.8). The VAS pain assessment was 1.6 (+/- 1.3) and the VAS function assessment was 7.9 (+/- 1.6). Of the 7 patients with a moderate result, 2 patients without additional ligament lesions suffered re-ruptures after and 13 months, respectively. The other 5 patients with a moderate result each had multiple accompanying injuries or pre-existing damage to the affected knee joint. CONCLUSION: The Clearfix screws achieved a clinical success rate of 82% in isolated meniscal tears in stable knee joints and a clinical success rate of 100% with additional ACL reconstruction. In view of the good clinical results and the simple procedure for use, the implant should be recommended for meniscal refixation.

Adolescent↗
PubMed2005

Levocetirizine in 1-2 year old children: pharmacokinetic and pharmacodynamic profile.

BACKGROUND: Levocetirizine is an antihistamine with high affinity and selectivity for H1-receptors, which exhibits an excellent benefit/risk ratio in the treatment of allergic rhinitis and urticaria. This is the first study performed with this drug in very young children. OBJECTIVE: The aim of this study was to confirm the intended regimen of levocetirizine (0.125 mg/kg twice a day) for further studies in children aged 12-24 months. MATERIAL AND METHODS: The pharmacokinetic/pharmacodynamic profile of levocetirizine was studied in 15 toddlers suffering from recurrent cough and other allergy-related symptoms, aged 20.7 +/- 3.7 months, and treated twice a day with 0.125 mg/kg for 90 days. A histamine-induced wheal and flare test (W&F) was performed prior to treatment. Blood was sampled at 1, 2, 4, 6, 9 and 12 hours after the first dose. Twelve hours after the evening dose on Days 3-6, and on day 90, a histamine-induced wheal and flare test was repeated and a blood sample was taken for trough value assessment. RESULTS: A peak plasma level of 286 +/- 68 ng/ml was observed after one hour. The elimination half-life was 4.1 +/- 0.7 hours, the apparent body clearance 1.05 +/- 0.10 ml/min/kg, and the apparent volume of distribution 0.37 +/- 0.06 l/kg. Morning trough values at Days 3-6, and at Day 90 were respectively 78 +/- 30 ng/ml and 110 +/- 86 ng/ml. The median inhibition of the wheal was 100% at Days 3-6, and Day 90. That of the flare was 99.6% at Days 3-6, and 98.9% at Day 90. The overall safety profile of this three-month open study was good. CONCLUSION: This first study with levocetirizine in children aged 12-24 months shows the adequate pharmacokinetic/pharmacodynamic profile and the good safety profile of 0.125 mg/kg levocetirizine given twice a day, which can be proposed for further studies in this age group.

Age Factors↗
PubMed2004

Tagged-particle dynamics in a hard-sphere system: mode-coupling theory analysis.

The predictions of the mode-coupling theory of the glass transition (MCT) for the tagged-particle density-correlation functions and the mean-squared displacement curves are compared quantitatively and in detail to results from Newtonian- and Brownian-dynamics simulations of a polydisperse quasi-hard-sphere system close to the glass transition. After correcting for a 17% error in the dynamical length scale and for a smaller error in the transition density, good agreement is found over a wide range of wave numbers and up to five orders of magnitude in time. Deviations are found at the highest densities studied, and for small wave vectors and the mean-squared displacement. Possible error sources not related to MCT are discussed in detail, thereby identifying more clearly the issues arising from the MCT approximation itself. The range of applicability of MCT for the different types of short-time dynamics is established through asymptotic analyses of the relaxation curves, examining the wave-number and density-dependent characteristic parameters. Approximations made in the description of the equilibrium static structure are shown to have a remarkable effect on the predicted numerical value for the glass-transition density. Effects of small polydispersity are also investigated, and shown to be negligible.

Journal Article↗
PubMed2004

Benzodiazepine receptor-dependent modulation of neutrophil (PMN) free amino- and alpha-keto acid profiles or immune functions.

We have examined the effects of midazolam, Ro 5-4864 (agonist for "peripheral" [p] benzodiazepine receptors [BR]), PK 11195 (antagonist for pBR), flumazenil (antagonist for "central" BR), naloxone (antagonist for opiate receptors) and the combination of midazolam and Ro 5-4864, PK 11195, flumazenil or naloxone on intracellular amino- and alpha-keto acids and the immune function markers superoxide anion (O(2)(-)), hydrogen peroxide (H(2)O(2)) and released myeloperoxidase (MPO) activity in neutrophils (PMN). Only midazolam and Ro 5-4864 led to significant changes in the dynamic PMN free amino- and alpha-keto acid pools. Concerning PMN immune function markers, midazolam and Ro 5-4864 significantly decreased O(2)(-) and H(2)O(2) formation and released MPO. When midazolam and Ro 5-4864 were applied together they appeared to act additively. Pre-incubation with PK 11195 partially neutralized the midazolam effects whereas flumazenil or naloxone showed no effects. We therefore believe that pBR are involved in the signal transmission of anesthetic-induced cellular metabolic changes in PMN.

Adult↗
PubMed2004

Effects of ornithine on neutrophil (PMN) free amino acid and alpha-keto acid profiles and immune functions in vitro.

The objective of this study was to determine the effects of ornithine on polymorphonuclear leucocyte (PMN) free amino- and alpha-keto acid profiles, superoxide anion (O2-) generation, hydrogen peroxide (H2O2) formation and released myeloperoxidase activity (MPO). Exogenous ornithine significantly increased PMN asparagine, glutamine, aspartate, glutamate, arginine, citrulline, alanine, alpha-ketoglutarate and pyruvate as intracellular ornithine increased. Concerning PMN immune function markers ornithine increased H2O2-generation and MPO activity while O2- -formation was decreased. We believe therefore that ornithine is important for affecting PMN "susceptible free amino- and alpha-keto acid pool" although the mechanisms are not yet clear. This may be one of the determinants in PMN nutrition considerably influencing and modulating PMN host defense capability.

Adult↗
PubMed2004

[Chronic hyperplastic laryngitis following treatment of hypertension with angiotensin converting enzyme-inhibitor].

We report the case of a 42 year old patient who developed chronic hyperplastic laryngitis during treatment with the angiotensin converting enzyme-inhibitor Cibacen 10. A severe cough and vocal restrictions with hoarseness were only incompletely cured after changing this anti-hypertensive medication to a adrenergic blocker, combined with a vocal rest and anti-inflammatory inhalation. Therefore we performed a laryngoscopy under general anesthesia and excised the swelling of the vocal cords. Additionally, voice therapy was prescribed and complete restitution achieved. Although hoarseness is documented as a potential side effect of angiotensin converting enzyme-inhibitors, morphological alterations in the vocal cords have not been linked to this type of drug. In our case, prolonged medication with Cibacen 10 led to chronic hyperplastic laryngitis. Initial coughing might have induced the trauma of the epithelium of the vocal cords. Due to the morphological alterations to the vocal cords the patient developed additional functional dysphonia.

Adult↗
PubMed2004

[What is the profile of palliative care in Germany. Results of a representative survey].

Since 1996 a working group of palliative care physicians has been developing a core documentation for palliative facilities. The data on a total of 1304 patients were collected in 2001. Treatment in palliative care units was provided for 531 patients until their death (Pat-V), 604 patients could be discharged home, and 169 patients were transferred to other facilities (Pat-E). Infusion therapy, physical therapy, positioning and mobilization, together with counseling and social services were initiated in more than 30% of the patients, while specific measures such as ascites or pleura puncture were instituted in less than 10%. Chemotherapy, radiotherapy, immunotherapy, urinary catheter, physical therapy, mobilization, positioning, psychotherapy, and social services were documented more frequently in the Pat-E group than in the Pat-V group. Chemotherapy was started in only 35 patients and radiotherapy in only 31 patients while they were in the palliative care unit. Parenteral nutrition, infusion therapy, wound management, and counseling were documented more frequently in the Pat-V group. Advanced directives were available for 9,9% of the patients omission or discontinuation of therapies was documented for 28,1%. Specific indications for the quality of palliative care provided could not be identified with the documentation instruments applied. The core documentation does however furnish data from a representative sample of in-patient palliative care in Germany, which can be used as a comparative data pool for other studies and quality assurance measures.

Death↗
PubMed2003

[Refixation of osteochondral fragments using absorbable implants. First results of a retrospective study].

An osteochondral lesion in a weight bearing joint causes therapeutic problems. Surgical therapy focuses on the restoration of the articular surface, unlimited motion of the joint and prevention of cartilaginous degeneration. A causal therapy to prevent posttraumatic osteoarthritis is the fixation of osteochondral fragments. Various absorbable implants for the purpose of refixation are available, but only a few have proved to be biocompatible. This retrospective study presents the preliminary results after refixation of osteochondral fragments of the ankle and knee joints. We used self-reinforced absorbable pins, nails and screws made of polylactide acid. The results for 15 patients with 17 fractures of 16 joints were evaluated. All patients were scored by the Tegner-activity-level, the McDermott-score and the DGKKT-score, and 13 of them were monitored by postoperative magnetic resonance imaging (MRI). The follow-up extended for an average of 14.3 months (range: 4-43 months). The clinical results for all patients were good (McDermott-score: Ø 89 points, DGKKT-score: Ø 78.8 points, Tegner: pre-op vs post-op=Ø 4.6 vs Ø 5.1) and the surgical therapy proved to be successful. The MRI showed the complete incorporation and vitality of the fragment as well as a congruence of the joint surface. The clinical course and the MRI gave little reference to an inflammatory reaction due to the implants that complicated the course of two patients. These results indicate that absorbable implants made of polylactide acid are biocompatible and effective in the fixation of osteochondral fragments.

Absorbable Implants↗
PubMed2003

[Results of palmar T-plate osteosynthesis in unstable fractures of the distal radius].

For unstable fractures of the distal radius, the dorsal plate requires exposure of the fragments, frequently spongioplasty, and usually removal of the implant later on. However, with the palmar approach for the reconstruction of the articular surface and restoration can easily be achieved with the T-plate. In the Traumatology Department of the University at Göttingen, we have gained experience in the treatment with the palmar T-plate in more than 400 patients. In a prospective study, we investigated the functional and radiological results after palmar T-plate osteosynthesis in Colles fractures. From September 1994 to December 1998 we treated 200 patients with the palmar T-plate (AO, 3.5 mm, titanium). 166 patients (83%), mean age 59 years, could be followed up >18 months. AO classification: A2:10, A3:45, B1:18, B2:10, C1:24, C2:40, C3:19. We compared group 1 (younger than 60 years, n=88) vs group 2 (older than 60 years, n=78). The patients' evaluation of the usability of the hand was normal in 56% and in 26,5% slightly reduced. 12,5% felt handicapped and 5% felt severely handicapped. 5% of the patients changed the domain hand, 15,4% at least partly. Function according to Lidström: 23% excellent, 58% good, 15% fair and 4% poor results. Radiological results according to Lidström were excellent and good in 88,3% and fair in 11,7%. Gartland and Werley score was excellent in 66%, good in 24%, fair in 6% and poor in 4%. There was no significant difference between group 1 and group 2 in the age-depending results. The secondary dislocation, the average dorsal tilt was 3 degrees, the mean shortening of the radius was 1,5 mm. We saw steps in the joint surface from 0,5-1 mm in 10%. An algodystrophy occurred in 5%. 12% of the patients complained of limited sensitive irritations of the medianus nerve most likely originating in the formerly used approach close to the medianus nerve. After changing this approach, we saw no irritation of the Nervus medianus among 50 patients so far. Evaluation of the functional and radiological investigations: The palmar T-plate has produced reliable and good results in the treatment of unstable distal fractures of the radius without angle-stable screws up to now. This type of osteosynthesis is stable for exercise and ensures early mobilization with good functional results even in elderly patients.

Adolescent↗
PubMed2003

[Teleteaching in otorhinolaryngology (part 1). Real-time transmission of a congress in picture and tone into the Internet].

The transmission of scientific seminars into the Internet represents a new application of modern technologies for teleteaching. We digitally recorded 74 seminars and discussions during the 8th annual meeting of the German Society of Skull Base Surgery with five cameras and eight microphones, and transformed the data live with the real-Producer using a video card.This transferred data stream was sent via ISDN (128 kbit/s) to a real-server at the university, which was used for distribution in the net. The seminars could be called up in the display format of 320x240 pixels with a delay of 3 min (minimum: 30 s, as a function of the connection of the user) at each computer with Internet entrance. Altogether,we registered 3,284 accesses to the presentations following the congress until June 2002. The quality of picture transmission (24-36 kbit/s) and the quality of tone (audio stream: 5 kbit/s) were sufficient to understand the contents of the slide, video or computer presentation. The transmission of scientific meetings into the Internet can increase, with a justifiable technical expenditure, their efficiency by the ubiquitous availability of the information and the extension of the audience.

Computer Systems↗
PubMed2003

[Teleteaching in otorhinolaryngology. Part 2: the European database "medicstream"].

Searching the medical literature is mainly characterized by the use of databases. The time for reviewing and printing a paper causes a delay between the first presentation of scientific results in a lecture and the appearance of the appropriate journal publication. Moreover, the possibilities for the integration of multimedia data are limited. Because of the development of new compression algorithms for audiovisual digitization software, the near simultaneous transmission of scientific presentations, both visually and aurally, has been possible since 1999. The section telemedicine of the interdisciplinary study group on image guided surgical navigation from the University of Leipzig has developed "medicstream" as a unique, audiovisual, scientific internetdatabase. It allows the documentation of presentations at congresses and courses, including the discussion,over a freely accessible, widely available homepage, using a home developed streaming technology. All presentations are examined by an authorized editorial committee consisting of representatives with different medical specializations for content before the admission to the data base. A total of 392 presentations from seven scientific meetings can be selected by an integrated search machine and viewed with Windows Media Player or Real Player using a conventional or faster internet connection to the homepage www.medicstream.de. The quality of the audiovisual transmission depends on the receiver-lateral data transmission rate,whereby the minimum variant of 56 kB/s is characterized by good detectability of the contents. In an analysis period of 242 days,we registered 44,199 accesses and 4,488 attendances. The telemedicine data base "medicstream" can optimize quality and extend medical education by live-streaming as well as by archiving scientific presentations as audiovisual data.

Congresses as Topic↗
PubMed2003

[Long-term results after conservative treatment of pediatric femoral shaft fractures].

The principles of treatment for fractures of the femoral shaft in children include conservative and operative management. Traditionally, these fractures have been treated conservatively with skeletal traction. More frequent consideration is being given to the psychological and economical outcome. At what age of the patient surgery can be performed is still open to debate. From 1988 to 1999, 52 children with closed femoral shaft fractures were treated conservatively in the Klinik für Unfallchirurgie, Plastische und Wiederherstellungschirurgie der Universität Göttingen (until 1994 Klinik für Allgemeinchirurgie). Overhead traction was applied in 27 children with a mean age of 19.9 months (group I), and a 90-90 skeletal traction was performed in 25 children with a mean age of 47 months (group II). This treatment was followed by spica casting on an outpatient basis. At a mean follow-up of 6 11/12 years (2 4/12-12 5/12) in 33 children all fractures were healed and no malalignment with clinical relevance could be observed. In four patients the limb overgrowth was 15-20 mm. The assessment of psychological and somatic aspects revealed disturbances in the family environment. The average length of hospitalization was much shorter in group I (mean: 17.4 days) than in group II (mean: 23.7 days). Our study confirms the good long-term results after conservative treatment of femoral shaft fractures in children up to 6 years. Social and psychological problems due to the prolonged period of hospitalization as well as the high costs of skeletal traction favor surgical treatment for children older than 3-4 years.

Age Factors↗
PubMed2003

[The cannulated blade plate 90 degrees for displaced proximal humeral fractures in elderly patients].

Aim of the study was to analyse the results following osteosynthesis of proximal humerus fractures with cannulated blade plate 90 degrees (Synthes, Mathys Medizinaltechnik AG, Bettlach, Schweiz) in elderly patients. Between 6/1998 and 12/1999 we treated 20 patients (12 female, 8 male) > 65 years (65-92 y, 75 y) with the cannulated blade plate (fracture type according to AO: 8 x 11-A3, 5 x 11-B1, 3 x 11-B2, 1 x 11-B3 und 3 x 11-C2). Regarding to mechanical and functional advantages we modified the 90 degrees angulation of the implant by bending intraoperatively up to 110-120 degrees. Early post-op physiotherapy was permitted. The radiological results of all patients were evaluated and in 13 patients a clinical follow-up (median 8 months) was obtained. According to the Constant-score 62 points on average were achieved, which corresponds to a satisfactory result (contralateral shoulder 92 points). Complications due to the implant were loosening of the blade plate in 3 cases (A3, B2, C2) and 1 perforation of the blade plate (C2). The consecutive reoperation consisted in a compound osteosynthesis with the blade plate (A3, B2) in 2 cases, a prosthetic replacement and a removal of the implant (C2) in 1 case respectively. Neither infection, major nerve and vessel trauma nor avascular necrosis occurred. The cannulated blade plate 90 degrees represents a justified alternative in the treatment of displaced fractures of the proximal humerus in elderly patients. Commendable indications are fracture types A and B according to AO with stable fixation of the blade plate in the humeral head, which allow early physiotherapy and avoid an alteration of the rotator cuff. C-type fractures tend to complications (2/3).

Aged↗
PubMed2002

Mode-coupling theory for structural and conformational dynamics of polymer melts.

A mode-coupling theory for dense polymeric systems is developed which unifyingly incorporates the segmental cage effect relevant for structural slowing down and polymer chain conformational degrees of freedom. An ideal glass transition of polymer melts is predicted which becomes molecular-weight independent for large molecules. The theory provides a microscopic justification for the use of the Rouse theory in polymer melts, and the results for Rouse-mode correlators and mean-squared displacements are in good agreement with computer simulation results.

Journal Article↗