Search PubMed⌕ Search

Biomedical subjects

R Rupp

Publications and source records attributed to R Rupp.

At least 19 recordsLinked to original sources
PubMed2003

Event-related beta EEG changes during wrist movements induced by functional electrical stimulation of forearm muscles in man.

Event-related beta electroencephalographic (EEG) changes were studied during wrist movements induced by functional electrical stimulation (FES) of the appropriate forearm muscles in healthy volunteers. Active and passive hand movements were investigated as control conditions. Significant EEG changes with respect to a pre-movement period were analyzed by calculating time-frequency maps of event-related (de-)synchronization (ERD/ERS) for 32 EEG channels recorded from sensorimotor and premotor areas. Immediately after the beginning of the FES movement, a prominent ERD was found, followed by a beta ERS similar to that observed after active or passive wrist movements. Both changes were maximal over the contralateral primary hand area. The main difference between active and stimulation-induced movements was that in the latter case no ERD was detectable prior to movement-onset. These findings suggest that the sensorimotor processing during FES involves some of the processes which are also involved in voluntary hand movements.

Adult↗
PubMed2003

[Stability and occlusion of six different femoral cement restrictors].

Cement restrictors play an integral part in modern cementing technique in total hip arthroplasty. By sealing the femoral cavity, distal cement leakage is prevented and the intramedullary pressure is increased. Thus both the ability of the cement to interdigitate with bone and secondarily the shear strength of the cement bone interface are enhanced. For this purpose various plug models are available, which differ in design and material. Six different cement restrictors were investigated in a biomechanical model with regard to intramedullary implantation pressure, insertion force and in particular stability and sealing ability. We performed a pressure and stability measurement in artificial saw bones during the insertion and standardised cement application and pressurisation. The REX Cement Stop, which is the only intramedullary expandable cement restrictor, yielded the best results in all of the parameters investigated. The flexible gelatin plugs (Biostop G, IMSET, Plugin Tech) also reached a sufficient canal occlusion and stability, but with slightly higher insertion pressures and forces. However, the more rigid polyethylene restrictors (BUCK, Universal Cement Restrictor) showed a reduced stability and poor sealing ability. The latter devices cannot be recommended for use with modern cementing techniques.

Arthroplasty, Replacement, Hip↗
PubMed2003

In vitro performance of intramedullary cement restrictors in total hip arthroplasty.

Contemporary cementing techniques in total hip arthroplasty include the use of a cement restrictor to occlude the intramedullary canal. As there are many different designs currently available it was the aim of our study to compare the stability of eight different systems. We investigated the displacement and the ability to occlude the femur of these cement restrictors during standardised cementing of artificial and fresh frozen femora. The maximal intramedullary pressures and the displacement of the plugs were continuously recorded and statistically evaluated. The results revealed significant differences between the tested cement restrictors. The expandable REX Cement Stop and the Exeter Plug achieved the highest stability and the least cement leakage. The more rigid designs (Palacos Plug, BUCK, Universal) in contrast showed inferior performance. Our biomechanical study emphasises the importance of cement restrictor selection, which can have a crucial influence on the fixation of a cemented total hip replacement.

Aged↗
PubMed2003

Genetic parameters for milk somatic cell scores and relationships with production traits in French Lacaune dairy sheep.

Records from 94,445 and 45,499 French Lacaune dairy ewes in first and second lactations, respectively, were used to estimate genetic parameters for somatic cell scores. Somatic cell count data came from an extensive recording scheme and sample testing that began in 1999 using the flocks enrolled in the official milk recording system. Somatic cell count data were from 2 to 4 test days per lactation. Lactation average and single test-day somatic cell scores were considered in multitrait sire models. The heritability estimate of lactation somatic cell score was close to 0.13 and similar for first and second parity. Heritabilities of somatic cell scores increased from first to fourth test day (from 0.07 to 0.11 in first lactation and from 0.05 to 0.13 in second lactation). Genetic correlations between somatic cell scores were high, usually more than 0.91, but lower between first test day and later test days in first lactation (0.64 to 0.88). The genetic correlations between lactation somatic cell score and milk yield, between lactation somatic cell score and fat content, and between lactation somatic cell score and protein content were 0.18, 0.04, and 0.03 in first lactation, respectively. The genetic antagonism between test day somatic cell score and milk yield measured in first lactation increased from beginning to the end of the lactation (0.05 to 0.23). This antagonism was slightly lower for somatic cell score in second lactation (from 0.09 to 0.14, and 0.08 for lactation mean). Environmental correlations in first lactation between lactation somatic cell score and milk yield, between lactation somatic cell score and fat content, and between lactation somatic cell score and protein content were -0.18, 0.13, and 0.30, respectively.

Animals↗
PubMed2002

Gait analysis on the treadmill - monitoring exercise in the treatment of paraplegia.

STUDY DESIGN: A prospective study was performed to evaluate the gait training of seven consecutive spinal cord injured patients and 10 controls on a treadmill using instrumented gait analysis and video documentation. OBJECTIVES: To determine whether it is possible to maintain gait motion within physiological limits during treadmill training. SETTING: Primary and secondary care unit for spinal cord injury, Heidelberg, Germany. METHODS: Treadmill training was instituted as early as possible. Gait analysis was performed when the patients were stable enough to walk without manual aid from therapists and enough endurance to allow measurements. A control group of healthy volunteers were examined as well. Video documentation and a camera system using passive markers were employed. RESULTS: Treadmill training started with weight reduction of 25% of bodyweight (18 (0-35) kg), maximum walking speed 0.28 (0.15-0.7) m/s and maximum walking duration 4.7 (3-7) min. At the end of the training, weight reduction decreased to 9.3 (0-20) kg, maximum walking speed increased to 0.67 (0.23-1.1) ms with a maximum walking duration of 11 (8-15) min. 3-D motion analysis of hip, knee and ankle demonstrated joint excursions almost entirely within the limits of normal gait. Exceptions were due to fixed contractures. CONCLUSIONS: Our data suggests that it is possible to perform early gait training on a treadmill with no supportive orthoses within the physiologic range of joint motion. The risk for repetitive stress injuries or other negative effects is low.

Adolescent↗
PubMed2002

[Bipolar , active electrode for 4-channel recording of dynamic surface EMG during electric stimulation].

In this paper we present an electrode for measuring the surface electromyogram (EMG) that combines high quality of signal recording with the ease of use in clinical routine. Additional requirements have been the use of the electrode in combination with electrical stimulation and under dynamic conditions like walking. Special focus was put on the minimization of movement artifacts by integration of a dual impedance transformer (active electrode) and by a self-adjusting fixation of the two contacts of the electrode via proprietary springs. An elaborate preparation of the skin is not necessary due to a very high input impedance of the amplifier. A special circuit for overvoltage protection makes the electrode suitable for use in the presence of high voltage stimulation pulses without the risk of destroying the FET-input stages.

Artifacts↗
PubMed2002

[A modular method for automated evaluation of gait analysis data].

A modular methodology for automated gait data evaluation: The aim of Instrumented Gait Analysis is to measure data such as joint kinematics or kinetics during gait in a quantitative way. The data evaluation for clinical purposes is often performed by experienced physicians (diagnosis of specific motion dysfunction, planning and validation of therapy). Due to subjective evaluation and complexity of the pathologies, there exists no objective, standardized data analysis method for these tasks. This article covers the development of a modular, computer-based methodology to quantify the degree of pathological gait in comparison to normal behavior, as well as to automatically search for interpretable gait abnormalities and to visualize the results. The outcomes are demonstrated with two different patient groups.

Biomechanical Phenomena↗
PubMed2002

[Reha-Stepper locomotion therapy in early rehabilitation of paraplegic patients].

Treadmill training with partial body weight support was shown to significantly improve the constitution and gait capacity of incomplete spinal cord injured (SCI) persons. The main requirement for application of this therapy is a sufficient capacity of the cardiovascular system. Most of the SCI patients do not comply with this requirement in the first few weeks after spinal cord injury, where spinal reflexes are frequently missing (spinal shock). To offer SCI patients a locomotion therapy at this early stage of rehabilitation we developed a novel, active tilt-table, the Reha-Stepper, that moves the lower limbs in an almost physiological manner in terms of kinematic and kinetic parameters. The tilt of the device can be continuously increased from horizontal to almost upright position adapted to the status of the patient.

Biomechanical Phenomena↗
PubMed2001

[The Freehand System: an implantable neuroprosthesis for functional electrostimulation of the upper extremity].

We report on the first experience with the Freehand system in German-speaking countries, an implantable neuroprosthesis developed for the functional electrical stimulation of the upper extremity. Indications for its use are neurological deficits of the cervical spinal cord with active mobility of the shoulder and elbow flexion in tetraplegics, ideally in C5/6 tetraplegics. A further precondition for the implantation of this system is an intact reflex arc of the muscles that are to be stimulated, i.e. of the forearm and hand. Central defects such as hemiparesis, cerebral palsies or athetoid disorders or peripheral nerve palsies (e.g. brachial plexus lesions) are no good indications for the implantation of the Freehand system. We report on patient selection criteria, preoperative percutaneous electrical stimulation, the surgical procedure itself with optional active tendon transpositions, the intensive postoperative rehabilitation program until the patient is able to use the system independently and the life-long after-care.

Arm↗
PubMed2000

Relationship between milk somatic-cell counts in the first lactation and clinical mastitis occurrence in the second lactation of French Holstein cows.

The relationship between 10 cell-level descriptors in the first lactation and the risk of clinical mastitis in the second lactation was studied in 10205 Holstein cows from 1254 commercial herds using logistic regression. These 10 cell descriptors were based on the mean cell level over the whole first lactation, on the cell level at the beginning or at the end of the first lactation or on the proportion of cell counts below or above given thresholds. Separate analyses were also performed for subsets of herds defined according to their clinical mastitis incidence risk and their lactation mean somatic-cell count (SCC). Odds of clinical mastitis in second lactation was highest (lowest) for high- (low-) yielding cows. All cell descriptors provided consistent results. Lower (higher) mean cell level, higher (lower) proportion of low SCC values, and lower (higher) proportion of high SCC values in the first lactation were associated with a lower (higher) risk of clinical mastitis in the second lactation. The same trends were observed in all subgroups of herds. Cows with the lowest mean SCC in the first lactation had the lowest risk for clinical mastitis in the second lactation. This suggests that selection for decreased SCC may effectively reduce clinical mastitis incidence and that the breeding goal should favor cows with the lowest observed SCC.

Animals↗
PubMed2000

A pilot study examining changes in dust lead loading on walls and ceilings after lead hazard control interventions.

The U.S. Department of Housing and Urban Development (HUD) guidelines on lead hazard control instruct contractors to clean floors, windows, walls, ceilings, and other horizontal surfaces to remove lead-contaminated dust and debris after lead interventions are conducted. This dust removal activity adds costs to each project. The need to clean floors and windows is well documented in the HUD guidelines. However, there is substantially less documentation to support the recommendation to clean walls and ceilings. We examined whether it is necessary to clean walls and ceilings after lead hazard control (LHC) interventions by comparing dust lead loadings measured on these surfaces before an LHC intervention to dust lead loadings after the intervention. Twenty-two dwelling units undergoing substantial LHC measures consistent with the HUD guidelines were enrolled in the study. There was a significant increase in dust lead loading on walls and ceilings between the pre- and postintervention. The change in wall dust lead loading was substantial and created potentially harmful lead exposures. Although statistically significant, the change in ceiling dust lead loading was minimal and the postintervention dust lead loadings were far below the existing federal floor dust lead clearance standard. These results strongly support the recommendations in the HUD guidelines to clean walls after LHC interventions and do not provide sufficient justification to alter the current recommendation to clean ceilings after lead work.

Child↗
PubMed1999

Achieving dust lead clearance standards after lead hazard control projects: an evaluation of the HUD-recommended cleaning procedure and an abbreviated alternative.

The U.S. Department of Housing and Urban Development's (HUD's) Guidelines for the Evaluation and Control of Lead-Based Paint Hazards in Housing strongly recommend that after lead hazard control interventions all walls, ceilings, floors, and other horizontal surfaces be cleaned using a three-step process to reduce lead-contaminated dust and debris. The three steps are: an initial vacuuming using a machine equipped with a high-efficiency particulate air (HEPA) filter (HEPA vacuum), wet wash with a lead cleaner, and a final HEPA vacuum. This study evaluated the effectiveness of two cleaning protocols: (1) the HUD-recommended three-step procedure, and (2) an abbreviated two-step cleaning procedure that omits the final HEPA vacuum. Cleaning procedures were evaluated in 27 dwelling units that had undergone significant lead hazard control interventions likely to produce lead dust. Dust lead samples were collected on floors and in window sills and troughs prior to the lead control hazard intervention, after the wet wash step of the cleaning procedure, and after completion of the second HEPA vacuuming. The results of the study demonstrate that dust lead surface loading on smooth and cleanable surfaces following the three-step and two-step cleaning procedures can achieve 1995 federal guidance dust clearance levels and levels substantially lower. Although the dust lead clearance rates before and after the second HEPA vacuum were the same, the time saved by omitting the second HEPA is small relative to the other elements of the cleaning process.

Air Pollution, Indoor↗
PubMed1999

Genetic parameters for clinical mastitis, somatic cell score, production, udder type traits, and milking ease in first lactation Holsteins.

Genetic parameters were estimated by restricted maximum likelihood with an animal model on first lactation data of 29,284 French Holstein cows for clinical mastitis, lactation somatic cell score, milking ease, production, and nine udder type traits. The heritability was low for clinical mastitis (0.024), moderate for lactation somatic cell score (0.17) and milking ease (0.17), and ranged from 0.17 to 0.30 for type traits. A high (0.72) but lower than unity genetic correlation was found between clinical mastitis and lactation somatic cell score and indicated that both traits were genetically favorably associated. The antagonism with production was stronger for clinical mastitis than for lactation somatic cell score (genetic correlations 0.45 and 0.15, respectively). Udder depth, fore-udder attachment, and udder balance were favorably associated with lactation somatic cell score and clinical mastitis with genetic correlations ranging from -0.29 to -0.46, whereas low correlations were found with teat length. Milking ease was found to be unfavorably correlated with lactation somatic cell score (genetic correlation 0.44) but not with clinical mastitis.

Animals↗
PubMed1998

Cation-exchange displacement chromatography for the purification of recombinant protein therapeutics from variants.

Removal of low level impurities that are closely related to the bioproduct is a commonly encountered challenge in the purification of biopharmaceuticals. These separations are typically carried out by using shallow linear salt gradients at relatively low column loadings, significantly limiting the throughput of the purification process. In this manuscript we examine the utility of displacement chromatography for the purification of recombinant human brain-derived neurotrophic factor, rHuBDNF. The utility of displacement chromatography is compared to gradient elution for the removal of variants of the rHuBDNF. The results demonstrate that displacement chromatography is capable of achieving high yields and purity at high column loadings. Displacements developed on 20 microns and 50 microns cation-exchange resins are shown to provide 8-fold and 4.5-fold increases in production rates, respectively, when compared to an existing linear gradient elution operation. These results demonstrate the efficacy of displacement chromatography for the purification of therapeutic proteins from complex feed streams.

Brain-Derived Neurotrophic Factor↗