[Sports fitness after prosthetic joint replacement].
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Athletic Injuries↗
Biomedical subjects
R Scholz
Publications and source records attributed to R Scholz.
[Use of a newly developed piezoelectrically driven drilling machine for MR-guided bone biopsies].
PURPOSE: Development and clinical testing of an MR-compatible bone biopsy system, to enable the sample collection from osteosclerotic or subcortical lesions for histological investigation under MR control. MATERIALS AND METHODS: A piezoelectrically driven drilling machine was constructed and tested in connection with an MR-compatible bone biopsy set in a vertical open MR scanner (0.5 T) on a phantom and 10 patients with ambiguous bone lesions. Images were obtained using T(1)-weighted spin-echo sequences and, in case of real-time imaging, a fast spoiled gradient-echo sequence. RESULTS: The influence of the enabled motor (RF-interference) leads to a reduction of the signal to noise ratio of the images, but can be minimised by appropriate measures. The observed slight field distorsions do not affect the image quality during real time acquisition in a substantial manner. No complications occurred. The extracted biopsy material was sufficient and of good quality. CONCLUSIONS: In spite of slightly restricted image quality, the described drilling machine combined with the bone biopsy set is well suited for MR-guided bone biopsies, which require the application of a motor driven drill. Its application within an interventional MR scanner is safe and its handling simple and manageable.
Biopsy, Needle↗
Coherent external and internal phonons in quasi-one-dimensional organic molecular crystals.
We have directly time resolved coherent phonon oscillations in quasi-one-dimensional organic crystals of MePTCDI ( N-N'-dimethylperylene-3,4,9,10-dicarboximide), using femtosecond pump-probe experiments. We observe both higher-energy oscillations caused by intramolecular vibrations (internal phonons) and, for the first time in a quasi-one-dimensional organic system, lower-energy modulations which are related to coherent lattice phonons (external phonons). For internal A(g) vibrations, the coherence decay time of about 2 ps is almost independent of the mode. In contrast, the damping time of the external phonons increases strongly with decreasing energy.
Journal Article↗
[Basic principles of medical assessment of the locomotor system].
Rendering a medical expert opinion on the musculoskeletal system is an extraordinary responsibility. Nearly all physicians are confronted with this medical task in their daily clinical practice. Difficulties encountered and misjudgments made in formulating an expert opinion are certainly primarily a result of insufficient knowledge of the sociomedical basis. Proper organization and compliance with a standardized structure are especially important for an expert opinion. Intensified teaching of the principles and importance of the medical expert opinion during medical training will not only result in optimization and acceleration of the sociomedical procedures, it will also awaken pleasure in this many-sided activity.
Disability Evaluation↗
Adoptive transfer of human natural killer cells in mice with severe combined immunodeficiency inhibits growth of Hsp70-expressing tumors.
In vitro, tumor-selective Hsp70 plasma membrane localization correlates with increased sensitivity to lysis mediated by a subpopulation of human natural killer (NK) cells that adhere to plastic following cytokine stimulation. In the present study, we analyzed the capacity of adoptively transferred human NK cells in SCID/beige mice for local tumor control and prevention of metastatic dissemination of Hsp70-expressing CX(+) and non-expressing CX(-) tumors following orthotopic (o.t.) injection. Both tumor sublines were derived by cell sorting of the original cell line, CX2, and thus exhibit an identical MHC and adhesion molecule expression pattern but differ with respect to Hsp70 plasma membrane expression. Viability of adherent, human NK cells in SCID/beige mice up to 18 days and the capacity to migrate have been demonstrated. Growth of Hsp70-expressing and non-expressing CX(+) and CX(-) tumor cells was completely suppressed when 10 x 10(6) NK cells were injected into the i.p. cavity on day 4 after inoculation of 2.5 x 10(6) tumor cells. Although a single injection of 5 or 2.5 x 10(6) NK cells was not sufficient to suppress tumor growth completely in all mice, the reduction in size of CX(+) tumors was significantly greater than that of CX(-) tumors. To mimic the clinical situation, ex vivo stimulated NK cells were injected i.v. on day 4 after o.t. injection of tumor cells. Under these conditions, growth of Hsp70-expressing primary tumors and metastases was suppressed. If CX(-) tumor cells were injected, 3 of 9 mice developed Hsp70-negative primary tumors. However, none of these mice developed distant metastases. In summary, our data indicate that Hsp70 acts as a recognition structure for adherent NK cells in a SCID/beige mouse model.
Animals↗
Discovery of High Proper-Motion Ancient White Dwarfs: Nearby Massive Compact Halo Objects?
We present the discovery and spectroscopic identification of two very high proper-motion ancient white dwarf stars, found in a systematic proper-motion survey. Their kinematics and apparent magnitude clearly indicate that they are halo members, while their optical spectra are almost identical to the recently identified cool halo white dwarf WD 0346+246. Canonical stellar halo models predict a white dwarf volume density that is 2 orders of magnitude less than the rho approximately 7x10-4 M middle dot in circle pc-3 inferred from this survey. With the caveat that the sample size is very small, it appears that a significant fraction, approximately 10%, of the local dark matter halo is in the form of very old, cool, white dwarfs.
Journal Article↗
M2-receptor subtype does not mediate muscarine-induced increases in [Ca(2+)](i) in nociceptive neurons of rat dorsal root ganglia.
Multiple muscarinic receptor subtypes are present on sensory neurons that may be involved in the modulation of nociception. In this study we focused on the presence of the muscarinic receptor subtypes, M2 and M3 (M2R, M3R), in adult rat lumbar dorsal root ganglia (DRG) at the functional ([Ca(2+)](i) measurement), transcriptional (RT-PCR), and translational level (immunohistochemistry). After 1 day in culture exposure of dissociated medium-sized neurons (20-35 micrometer diam) to muscarine was followed by rises in [Ca(2+)](i) in 76% of the neurons. The [Ca(2+)](i) increase was absent after removal of extracellular calcium and did not desensitize after repetitive application of the agonist. This rise in [Ca(2+)](i) may be explained by the expression of M3R, which can induce release of calcium from internal stores via inositoltrisphospate. Indeed the effect was antagonized by the muscarinic receptor antagonist atropine as well as by the M3R antagonist, 4-diphenylacetoxy-N-(2 chloroethyl)-piperidine hydrochloride (4-DAMP). The pharmacological identification of M3R was corroborated by RT-PCR of total RNA and single-cell RT-PCR, which revealed the presence of mRNA for M3R in lumbar DRG and in single sensory neurons. In addition, RT-PCR also revealed the expression of M2R, which did not seem to contribute to the calcium changes since it was not prevented by the M2 receptor antagonist, gallamine. Immunohistochemistry demonstrated the presence of M2R and M3R in medium-sized lumbar DRG neurons that also coexpressed binding sites for the lectin I-B4, a marker for mainly cutaneous nociceptors. The occurrence of muscarinic receptors in putative nociceptive I-B4-positive neurons suggests the involvement of these acetylcholine receptors in the modulation of processing of nociceptive stimuli.
Animals↗
Hsp70 plasma membrane expression on primary tumor biopsy material and bone marrow of leukemic patients.
A tumor-selective cell surface localization of heat shock protein 70 (Hsp70), the major heat-inducible member of the Hsp70 group, correlates with an increased sensitivity to lysis mediated by human natural killer (NK) cells and, therefore, might be of clinical relevance. With the exception of mammary carcinomas, an Hsp70 plasma membrane expression was found on freshly isolated human biopsy material of colorectal, lung, neuronal, and pancreas carcinomas, liver metastases, and leukemic blasts of patients with acute myelogenous leukemia. Since normal tissues and bone marrow of healthy human individuals do not express Hsp70 on the cell surface, Hsp70 can be considered as a tumor-selective structure in vivo. Furthermore, we demonstrate that autologous, Hsp70-positive leukemic blasts can be killed by NK cells stimulated with low doses of interleukin 2 plus recombinant Hsp70 protein.
Adenocarcinoma↗
A new model of thermal inactivation and its application to clonogenic survival data for WiDr human colonic adenocarcinoma cells.
Based on the analysis of clonogenic survival data for human colonic adenocarcinoma cells (WiDr) after a single heating, a new model is proposed to describe cell survival after hyperthermia quantitatively. The effects of heat are explained as heat-induced cell damage assuming a first-order (single-hit) and a second-order (cumulative damage) process. Thus cell survival at a specified temperature can be described by the linear-quadratic (LQ) model. The proposed model is based on an alternative definition of the (single) thermal dose, given as the (normalized) product of heating time and a specified nonlinear function of the increase in temperature (relative to a threshold temperature) to be interpreted as the thermal dose rate. In further analogy to the modeling of the effects of low-dose-rate radiation, an inherent capacity of the cells to repair sublethal damage is assumed, and these effects are quantified by the usual g factor measuring incomplete repair effects. The model defines thermal dose-response and isoeffect dose relationships, enabling a direct (i. e. single-step) analysis of the available thermal response data. Additionally, the analysis of our data based on heating times in the range from 0 to 360 min and temperatures from 41 to 46 degrees C and covering a broad spectrum of different densities of cells seeded for colony formation did not yield any evidence of the existence of a breaking point usually derived from Arrhenius plots based on the single-hit, multitarget model and the Arrhenius equation. The model includes no specific assumptions describing the development of thermotolerance, which can be assumed to be negligible under our experimental conditions. The proposed thermal dose-response model correlates satisfactorily with the in vitro survival data for WiDr adenocarcinoma cells.
Adenocarcinoma↗
[Open lumbar intervertebral disk operation. Technique and results].
Various operative techniques are available for the treatment of lumbar disc herniation. The conventional lumbar discotomy is currently considered to be the standard procedure. Several large statistical studies have shown that the results in the majority of cases are very good and the complication rate is low if it is carried out correctly. A particular advantage of this technique is that almost all indications can be handled with a procedure that can be extended if necessary. Despite the availability of newer refined techniques (microdiscectomy or percutaneous procedures), the open lumbar discotomy still has an outstanding role in the management of lumbar disc herniation. Failure results more frequently from false indications or inadequate preoperative planning and less from technical variations.
Diskectomy↗
Long-lasting contamination of a vitrectomy apparatus with Serratia marcescens.
OBJECTIVE: To investigate the contamination of a vitrectomy apparatus with Serratia marcescens. DESIGN: Descriptive microbiological and molecular environmental study. SETTING: An 1,800-bed university hospital. RESULTS: S. marcescens was found inside the vitrectomy apparatus at the pressure transducer. Molecular typing by randomly amplified polymorphic DNA-automated laser fluorescence analysis and pulsed-field gel electrophoresis identified a single pattern for all strains isolated from the apparatus. Surprisingly, the contaminating strain was identical to two strains of S. marcescens isolated nearly 2 years earlier from two patients who were involved in a small outbreak of acute postoperative endophthalmitis following cataract surgery at another hospital. The emergency vitrectomies in these patients were performed at our hospital with the same apparatus that was found to be contaminated 2 years later. CONCLUSION: Performing a systematic environmental search for the assumed bacterial reservoir within the system of the vitrectomy apparatus finally made it possible to find and eliminate the nidus for the gram-negative rod. Molecular typing demonstrated that all isolates belonged to a single genotype, and revealed unexpectedly a link to two vitrectomies performed 2 years earlier. The data support the hypothesis that the source of the contamination was one of these patients, and thus contamination of the apparatus was present for almost 2 years.
DNA, Bacterial↗
[47th Annual Meeting of the North-German Orthopedic Society. Leipzig, 20 June 1998].
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Germany↗
[Therapy studies of the Austrian Breast Cancer Group (ABC)].
The Austrian Breast Cancer Group (ABC) consisting of more than 60 participating centers in Austria has randomized more than 5800 patients in 11 randomized trials since 1984. At present, roughly 30% of all patients with the diagnosis primary breast cancer are accrued in protocols throughout the country. Due to specific activities, the breast conservation rate raised from an initial 20% to more than 60% in the last years. Multicenter trials are not only the basis for progress in medicine but also tools for quality control and quality improvement.
Antineoplastic Agents, Hormonal↗
Single-Electron Subpicosecond Coherent Dynamics in KBr F Centers.
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Journal Article↗
Recognition performance of subjects with color-vision deficiencies on a polychromatic sonar screen for ship navigation.
To facilitate differentiation between objects that are approaching, stationary, and moving away, these objects are represented in different colors on the screens of sonar locating devices used in ship navigation. Yellow represents stationary objects, and represents approaching objects, and green represents those objects moving away. A total of 46 subjects with normal color vision and 184 individuals with color-vision deficiencies, among them 29 deuteranopic, 100 deuteranomalous, 21 protanopic and 34 protanomalous individuals, were investigated for their ability to identify different signals. Ten different objects were presented for a period of 64 s each. As a minimal requirement it was established that 50% of the respective experimental group be capable of recognizing the objects within half of this time. Whereas 73.3% of the subjects with normal color vision could meet this requirement, none of the subjects in the different groups with color-vision deficiencies could do so. Only 16.1% of the deuteranopic subjects, 33.1% of the deuteranomalous individuals, 16.2% of the protanopic subjects, and 37.6% of the protanomalous individuals detected all objects within 32 s. No appreciable difference in the ability to recognize signals occurred among the different groups of subjects with color-vision deficiencies.
Color Perception↗
Insulin-induced translocation of GLUT 4 in skeletal muscle of insulin-resistant Zucker rats.
The genetically obese Zucker rat (fa/fa) is an animal model with severe insulin resistance of the skeletal muscle. We investigated whether a defect of insulin-dependent glucose transporter (GLUT 4) translocation might contribute to the pathogenesis of the insulin-resistant state. fa/fa rats, lean controls (Fa/Fa) as well as normal Wistar rats were injected intraperitoneally with insulin and were killed after 2 or 20 min, respectively. Subcellular fractions were prepared from hind-limb skeletal muscle and were characterized by determination of marker-enzyme activities and immunoblotting applying antibodies against alpha 1 Na+/K+ ATPase. The relative amounts of GLUT 1 and GLUT 4 were determined in the fractions by immunoblotting with the respective antibodies. Insulin induced an approximately two-fold increase of GLUT 4 in a plasma membrane and transverse tubule enriched fraction and a decrease in the low density enriched membrane fraction in all three groups of rats. There was a high individual variation in GLUT 4 translocation efficiency within the groups. However, no statistically significant difference was noted between the groups. No effect of insulin was detectable on the distribution of GLUT 1 or alpha 1 Na+K+ ATPase. The data suggest that skeletal muscle insulin resistance of obese Zucker rats is not associated with a lack of GLUT 4 translocation.
Animals↗
[Visual acuity of military personnel with civilian or military driver's license on consulting an ophthalmologist].
Visual acuity was tested in 1861 members of the German armed forces who possessed military or civilian driving licences, first by means of a screening test (Roden-stock R12) and second by an ophthalmologist observing German Industrial Standard 58220, part 3. The tests were done with the patients wearing any corrective spectacles in use before the appointment. In 27.6% of all subjects the monocular or binocular visual acuity was less than 1.0. Binocular visual acuity less than 1.0 was found in 17.0%, less than 0.8 in 7.3% and less than 0.5 in 0.9%. After adjustment of the corrective lenses by the ophthalmologist these figures were reduced to visual acuity less than 1.0 in 1.6%, less than 0.8 in 0.4% and less than 0.5 in 0.1%. The frequency of suboptimal visual acuity showed no difference in driving licence classes. We found fewer cases of suboptimal visual acuity in our patients than Kratz and Häseker found in the civilian community in the study published in 1986. The age distribution was also different. In contrast to former publications, which showed an age-related progression, our population had the lowest number of subjects with subnormal visual acuity in the age group 35-45 years. The screening test for visual acuity and the test by the ophthalmologist showed the same results in 76.8% of cases.
Adult↗
Histology of tissue adjacent to an HAC-coated femoral prosthesis. A case report.
We studied the fixation of a cementless titanium femoral prosthesis partially coated with hydroxyapatite ceramic (HAC) 10.4 months after implantation. Histomorphological investigation showed extensive new bone formation between the HAC coating and the bone bed; morphometry showed bone contact indices of up to 91.60%. There were a number of resorption lacunae on the HAC coat with depths of up to 76.6 microns and widths of up to 453 microns. Our results confirmed that considerable bone remodelling had taken place and that the apatite-coated prosthesis had united with bone despite the lack of appreciable immediate press-fit. Hydroxyapatite particles which had been released did not appear to show any negative effects on the stability of the implant.
Aged↗