Publications by authors named "Geyer H"

Boldenone (androsta-1,4-dien-17beta-ol-3-one, Bo) is an anabolic steroid known to have been used in cattle breeding or equine sport as a doping agent for many years. Although not clinically approved for human application, Bo or its main metabolite 5beta-androst-1-en-17beta-ol-3-one (BM1) were detected in several doping control samples. For more than 15 years the possibility of endogenous Bo production in human beings has been discussed.

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The following case report describes a selenium toxicosis in a pig-fattening farm of two finisher groups. The diseased animals partly showed ataxia and paresis or intense lameness in connection with band-like ablation of the epidermis at the coronary band. Some of them suffered from alopecia.

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Sialic acids usually represent the terminal monosaccharide of glycoconjugates and are directly involved in many biological processes. The cellular concentration of their nucleotide-activated form is one pacemaker for the highly variable sialylation of glycoconjugates. Hence, the determination of CMP-sialic acid levels is an important factor to understand the complex glycosylation machinery of cells and to standardize the production of glycotherapeutics.

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The N- and O-glycans of Arianta arbustorum, Achatina fulica, Arion lusitanicus and Planorbarius corneus were analysed for their monosaccharide pattern by reversed-phase HPLC after labelling with 2-aminobenzoic acid or 3-methyl-1-phenyl-2-pyrazolin-5-one and by gas chromatography-mass spectrometry. Glucosamine, galactosamine, mannose, galactose, glucose, fucose and xylose were identified. Furthermore, three different methylated sugars were detected: 3-O-methyl-mannose and 3-O-methyl-galactose were confirmed to be a common snail feature; 4-O-methyl-galactose was detected for the first time in snails.

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While neuroscientists identify increasingly complex neural circuits that control animal and human gait, biomechanists find that locomotion requires little control if principles of legged mechanics are heeded that shape and exploit the dynamics of legged systems. Here, we show that muscle reflexes could be vital to link these two observations. We develop a model of human locomotion that is controlled by muscle reflexes which encode principles of legged mechanics.

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The annual update of the list of prohibited substances and doping methods as issued by the World Anti-Doping Agency (WADA) allows the implementation of most recent considerations of performance manipulation and emerging therapeutics into human sports doping control programmes. The annual banned-substance review for human doping controls critically summarizes recent innovations in analytical approaches that support the efforts of convicting cheating athletes by improved or newly established methods that focus on known as well as newly outlawed substances and doping methods. In the current review, literature published between October 2008 and September 2009 reporting on new and/or enhanced procedures and techniques for doping analysis, as well as aspects relevant to the doping control arena, was considered to complement the 2009 annual banned-substance review.

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The authors summarize the recent developments in speckle-tracking echocardiography (STE), a relatively new technique that can be used in conjunction with two-dimensional or three-dimensional echocardiography for resolving the multidirectional components of left ventricular (LV) deformation. The tracking system is based on grayscale B-mode images and is obtained by automatic measurement of the distance between 2 pixels of an LV segment during the cardiac cycle, independent of the angle of insonation. The integration of STE with real-time cardiac ultrasound imaging overcomes some of the limitations of previous work in the field and has the potential to provide a unified framework to more accurately quantify the regional and global function of the left ventricle.

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Non-steroidal and tissue-selective anabolic agents such as selective androgen receptor modulators (SARMs) represent a promising class of therapeutics for the treatment of various diseases such as sarcopenia or cancer cachexia. Advanced compounds of SARMs are based on an arylpropionamide-derived structure and leading drug candidates have successfully completed phase-II-clinical trials. Although none of these therapeutics have been approved, their performance-enhancing qualities and the black-market availability of these products makes them a viable target for misuse in the athletic community.

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Article Synopsis
  • Epitestosterone (EpiT) is on the World Anti-Doping Agency's list of banned substances, primarily because athletes may misuse it to mask testosterone usage by altering the T/EpiT urine ratio, even though it doesn't build muscle.
  • A study was conducted on 40 mg of EpiT to track its metabolites in urine, focusing on two specific compounds, 5alpha- and 5beta-androstane-3alpha,17 alpha-diol, to better identify EpiT misuse in athletes.
  • A new method was developed to measure carbon isotope ratios in urine samples, improving the detection of EpiT and its metabolites, which led to a doubled detection time for EpiT use using both
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According to the regulations of the World Anti-Doping Agency (WADA), the use of cannabinoids is forbidden in competition. In doping controls, the detection of cannabinoid misuse is based on the analysis of the non-psychoactive metabolite 11-nor-9-carboxy-delta-9-tetrahydrocannabinol (carboxy-THC). The determination of values greater than 15 ng/mL in urine represents an adverse analytical finding; however, no accurate prediction of the time of application is possible as the half-life of carboxy-THC ranges between three and four days.

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Stimulants have been frequently detected in doping control samples and represent a structurally diverse class of compounds. Comprehensive sports drug-testing procedures have been developed using gas or liquid chromatography combined with mass spectrometric detection, and they have revealed various adverse analytical findings, as demonstrated with 2 examples, 4-methylhexan-2-amine and methoxyphenamine. Moreover, the necessity of controlling the use or misuse of stimulating agents is outlined by means of pseudoephedrine, a compound that was prohibited in sports until the end of 2003.

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Oligosialic and polysialic acids (oligo/polySia) are characterized by high structural diversity, because of different types of sialic acids and glycosidic linkages. Although several methods have been described for the analysis of oligo/polySia, only high-performance liquid chromatography (HPLC) analysis in conjunction with 1,2-diamino-4,5-methylenedioxybenzene labeling, fluorometric C7/C9 detection, Western blotting, and matrix-assisted laser desorption/ionization time-of-flight mass spectroscopy (MALDI-TOF-MS) of lactonized oligo/polySia species, require submicrogram amounts of analyte. Since these methods do not provide detailed structural information, this study is focused on the characterization of oligo/polySia by tandem mass spectrometry (MS/MS).

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Control schemes for powered ankle-foot prostheses rely upon fixed torque-ankle state relationships obtained from measurements of intact humans walking at target speeds and across known terrains. Although effective at their intended gait speed and terrain, these controllers do not allow for adaptation to environmental disturbances such as speed transients and terrain variation. Here we present an adaptive muscle-reflex controller, based on simulation studies, that utilizes an ankle plantar flexor comprising a Hill-type muscle with a positive force feedback reflex.

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As a result of the lack of basic microscopic anatomy of the elephants' foot, this study deals with the normal microscopic morphology of both the Asian (Elephas maximus) and African (Loxodonta africana) elephant foot with consideration of pathologic changes. A total of 727 histologic samples from defined locations of 24 hooves of both species (17 Asian and seven African species) were studied, measured, and evaluated. Minor differences between the feet and species are seen histologically.

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Activities concerning the fight against doping with regard to the Paralympic Games have been initiated in 1984, when first doping controls were conducted. The foundation of the International Paralympic Committee exactly 20 years ago (1989) considerably supported systematic sports drug-testing programs specifically designed to meet the particular challenges related to disabled sports, which yielded a variety of adverse analytical findings (e.g.

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The detection of misuse with naturally occurring steroids is a great challenge for doping control laboratories. Intake of natural anabolic steroids alters the steroid profile. Thus, screening for exogenous use of these steroids can be established by monitoring a range of endogenous steroids, which constitute the steroid profile, and evaluate their concentrations and ratios against reference ranges.

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Since January 2009, the list of prohibited substances and methods of doping as established by the World Anti-Doping Agency includes new therapeutics such as the peroxisome-proliferator-activated receptor (PPAR)-delta agonist GW1516, which is categorized as a gene doping substance. GW1516 has completed phase II and IV clinical trials regarding dyslipidemia and the regulation of the lipoprotein transport in metabolic syndrome conditions; however, its potential to also improve athletic performance due to the upregulation of genes associated with oxidative metabolism and a modified substrate preference that shifted from carbohydrate to lipid consumption has led to a ban of this compound in elite sport. In a recent report, two presumably mono-oxygenated and bisoxygenated urinary metabolites of GW1516 were presented, which could serve as target analytes for doping control purposes after full characterization.

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Purpose: To evaluate the role of pre-interventional fused high resolution T2-weighted images with parametrically analysed dynamic contrast enhanced T1-weighted magnetic resonance (MR) images (DCE-MRI) and 1H magnetic resonance spectroscopy (MRS) for a precise biopsy for the detection of prostate cancer and for the delineation of intraprostatic subvolumes for intensity modulated radiation therapy (IMRT).

Inclusion Criteria: Pathological prostate-specific antigen values (PSA) and/or previously negative transrectal ultrasound guided biopsy. Standardised biopsy of the prostate divided into 20 regions.

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Oocyte maturation is a prerequisite for successful fertilization. Growing evidence suggests that not only the oocyte but also the surrounding zona pellucida has to undergo maturational changes. In the pig, two-dimensional electrophoretic analysis demonstrated an acidic shift of the zona pellucida glycoproteins of about 1.

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Little is known about the prevalence and motives of supplement use among elite young athletes who compete on national and international levels. Therefore, the current survey was performed to assess information regarding the past and present use of dietary supplements among 164 elite young athletes (16.6 +/- 3.

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The following case report describes the treatment of canker in a 14 years old warmblood gelding. The horse showed the typical appearance with caseous surface and early detachment of the superficial horn layers. The histological results show a severe degradation in the germinal layer of the epidermis of the frog.

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The cell adhesion molecule CD24 is a highly glycosylated glycoprotein that plays important roles in the central nervous system, the immune system and in tumor biology. Since CD24 comprises only a short protein core of approximately 30 amino acids and low conservation among species, it has been proposed that the functions of CD24 are mediated by its glycosylation pattern. Our present study provides evidence that interaction of CD24 with the cell adhesion molecule L1 is mediated by O-linked glycans carrying alpha2,3-linked sialic acid.

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