Biomedical subjects

R Schmidt

Publications and source records attributed to R Schmidt.

At least 955 records · Page 53Linked to original sources

PubMedDate not supplied

[Decompensation of a supinator syndrome in submuscular lipoma. A rare differential diagnosis of elbow pain].

Important differential diagnoses to epicondylitis humeri radialis are the nerve compression syndromes of the elbow. After a long period of conservative treatment, paresis of the motor branch of nervus radialis in this case led to the diagnosis and surgical treatment showing an unknown submuscular lipoma as the cause of a supinator syndrome with paresis of the finger extensors. In cases of therapy-resistant pain of the elbow, especially resistant to the conservative therapy of an epicondylitis humeri radialis, a nontraumatic supinator syndrome should be considered as a differential diagnosis. A tumor as the cause of a compression syndrome of the motor branch of the nervus radialis is very rare.

Decompression, Surgical↗

PubMedDate not supplied

[Arm motion analysis: a new method and its clinical application].

AIM: An investigation into the objective criteria of shoulder mobility possesses special meaning for diagnostic documentation, the evaluation of therapy and the effects of rehabilitation in the treatment of diseases of the shoulder. In order to ascertain the criteria which characterise shoulder mobility, it is necessary to have a tool available that is objective, comparable and allows the complexity, variability and range of motion to be recorded. Motion analysis represents one such standard procedure used to measure joint movement. METHOD: Accordingly, a marker- based motion analysis of the wrist and elbow, a marker-based three-dimensional motion analysis system for the upper extremities was developed. We evaluated 10 healthy subjects without shoulder conditions and 8 patients with impingement syndrome (7 operative, 1 conservative therapy). RESULTS: The healthy subjects revealed a reproducible motion curve for the specific motion tested. The curves were defined as the normal standard and we used them for comparative purposes. In the treatment group, an improvement of the 3D range of motion could be documented for the affected shoulder following rehabilitation. CONCLUSION: It can be stated that this newly developed marker-based procedure for the three-dimensional motion analysis is suitable for recording complex unconstrained movements. This was found to be more relevant for the assessment of the ability of patients to manage the physical demands of daily living than traditional clinical tests. Furthermore, the information gained from motion analysis of the upper extremities will play a valuable role in the future for quality control during diagnosis and treatment, as well as for the design of shoulder rehabilitation programs.

Adult↗

PubMedDate not supplied

[Sagittal alignment and segmental range of motion after total disc replacement of the lumbar spine].

AIM: To evaluate changes in static and dynamic values, X-rays of patients who underwent total disc replacement for degenerative disc disease were analyzed. METHOD: An analysis of pre- and postoperative lateral X-rays in 22 patients with 24 total disc replacements (Prodics, Spine Solutions) was performed. The total lumbar lordosis, the segmental lordosis angle, the disc height and the range of motion in the operated level were measured. RESULTS: Postoperatively a significant increase was observed for the following parameters: the anterior (pre: 9.0 +/- 3.4 mm; post: 16.7 +/- 2.4 mm; p < 0.001) and posterior (pre: 4.4 +/- 1.3 mm; post: 8.8 +/- 1.3 mm; p < 0.001) disc height and the segmental lordosis angle (pre: 20 degrees +/- 7.2 degrees; post: 27.7 degrees +/- 7.4 degrees; p < 0.001). Statistically no significant changes could be observed postoperatively for the total lumbar lordosis (pre: 56.2 degrees +/- 10.7 degrees; post: 58.6 degrees +/- 9.3 degrees; p = 0.196) and the range of motion (pre: 5.0 degrees +/- 4.0 degrees; post: 5.9 degrees +/- 3.5 degrees; p = 0.293). CONCLUSION: Total disc replacement for degenerative disc disease of the lumbar spine with the current concept does not alter the range of motion but significantly increases the disc height. The significant increase in segmental lordosis without a change in the total lumbar lordosis accounts for a change in lordosis in adjacent segments.

Adult↗

PubMedDate not supplied

[Prognosis, surgical therapy and progression in cervical and upper-thoracic tumor osteolysis].

INTRODUCTION: This study analyzes the early and mid-term results of our modular rod-screw implant system for the posterior instrumentation of the occipito-cervical, cervical and cervico-thoracic spine (neon occipito-cervical system, Ulrich, Germany) in patients with tumor osteolysis. The prognosis of the patients was evaluated using the Tokuhashi score. METHODS: The cervical and upper thoracic spines of 14 patients (7 males, 7 females, mean age 61 years, range 40-77 years) with osteolysis due to plasmocytoma (n = 2), bronchial (n = 3), mamma (n = 4), thyroid (n = 2), esophageal (n = 1) and pancreatic (n = 1) carcinomas as well as melanoma (n = 1) were instrumentated between June 2001 and April 2004. RESULTS: A stable fixation without loosening or failure of the fixator system was achieved in all cases. No impairment of the neurological status was observed. In our cohort different prognosis scores failed to make a reliable estimate of the expected survival at the time of surgery. CONCLUSION: Posterior instrumentation of the cervical spine including the occipito-cervical and the cervico-thoracic regions with a modular angle-stable rod-screw implant system (neon) offers good stabilization and allows simultaneous decompression. Since tumor masses are predominantly located in the anterior portion of the spine, blood loss can be controlled well. In this patient collective appears difficult to estimate the time of survival by a scoring system.

Adult↗

PubMedDate not supplied

[The potential for training of proprioceptive and coordinative parameters in patients with chronic ankle instability].

AIM: This study was aimed at assessing the outcome of physical therapy based on both subjective patient's satisfaction and objective measurement of peroneal reaction time in patients with chronic ankle instability. METHOD: 25 patients with chronic ankle instability based on functional deficits were included. Physical therapy consisted in a 6 weeklong program with muscle strengthening and coordination exercises for one hour, three times a week. Before starting physical therapy as well as two weeks after finishing the program, patients underwent both a clinical exam as well as measurement of their peroneal reaction time. RESULTS: Following physical therapy peroneal reaction time of the long (p = 0.0001) and short (p = 0.0003) peroneal muscles significantly decreased. Prior to physical therapy the Kitaoka score was calculated to be 72.2 (+/- 18.7), the post treatment value was 93.3 (+/- 11.7) with a p-value of < 0.001. As for subjective patient's assessment on a scale of 1-10 with 1 being the least and 10 the most satisfied with therapeutical outcome, patients gave an average post treatment score of 8.3 (+/- 1.9). CONCLUSION: Measurement of PRT can be used as a helpful diagnostic parameter, as a parameter for quality control and for verification of therapy results. Specific physiotherapy leads to good clinical results and increased PRT.

Adolescent↗

PubMedDate not supplied

[Surgical treatment and evaluation of prognostic factors in spinal metastases of renal cell carcinoma].

AIM: The aim of this study was the evaluation of surgical results and prognostic factors in spinal metastases of renal cancer. METHODS: 37 surgical patients with spinal metastases of renal cell carcinoma were retrospectively analysed. In 2 patients the cervical, in 16 patients the thoracic, in 4 patients the thoraco-lumbar and in 16 patients the lumbar spine was involved. RESULTS: In 11 cases (29.7 %) a combined posterior-anterior spondylodesis with vertebral body replacement, in 26 cases (70.3 %) a single posterior instrumentation was done. Perioperatively, 24 complications appeared, 4 of them were lethal. Postoperatively, the neurological situation was unchanged in 26 patients, dischanged in 4 patients and improved in 7 patients. The level of pain was unchanged in 10 patients, dischanged in 3 patients and improved in 24 patients. The mean postoperative survival was 13.6 months. For the postoperative survival the Karnofsky-Index and the Frankel-Score were univariate highly significant, the factors nutritional condition and latency between the primary tumor and the development of spinal metastases showed a lower significancy. No prognostical influence for the postoperative survival could be detected for the factors gender, age, localisation of the metastases, type of operation and the factor solitary/multiple metastases. The multivariate analyses did not attempt any of the univariate significant prognostic factors for the postoperative survival. The postoperative survival was significantly (p: 0.0030) influenced by postoperative adjuvant therapy (radio- and/or chemotherapy). The analysis of each adjuvant therapy form (i. e. chemo-, radio- and combined therapy) attempts this prognostic effect (p: 0.0229). CONCLUSION: In most patients with spinal metastases of renal cell carcinoma, the singular posterior intrumentation combined with a decompression is a sufficient therapy. To avoid posterior implant failure, in patients with a prognosticated survival of more than one year, a combined posterior-anterior spondylodesis with vertebral body replacement should be done. The prognostic influence of an adjuvant postoperative treatment in the present study must be interpreted in the context of this small, highly selected patient collective. Further standardized studies should be performed to evaluate the prognostic influence of an adjuvant therapy.

Adult↗

PubMedDate not supplied

Evaluation of text telephones designed for people with impaired hearing or speech.

PURPOSE: The primary aim of this study was to assess a range of desktop text telephones and to provide comparative data to enable healthcare professionals and users to make informed choices when selecting products. Our second objective was to highlight the effect of different product features on ease of communication. METHODS: We used three methods of evaluation. (1) User trials of seven desktop textphones were carried out by 28 people. (2) The same desktop textphones, along with three portable models, were appraised by two independent assessors. (3) All 10 products were discussed by groups of hearing and hearing-impaired users-112 in all. RESULTS AND CONCLUSIONS: Participant ratings, user comments, and observations of sample conversations all revealed that ease of communication was greatly influenced by the type of technology employed to connect the textphone to the telephone network. Overall, conversations held on text telephones with a direct connection were more successful and produced fewer garbled messages than those made with an acoustic connection. Although individual preferences were expressed, other defining features such as the size of keyboard, display type and size of text did not have a comparable impact on communication. Future research and development could focus on the design of products that would cater simultaneously for the communication needs of hearing, deaf and speech-impaired users.

Adolescent↗

PubMedDate not supplied

HPLC: a tool for the analysis of T-2 toxin and HT-2 toxin in cereals.

An analytical procedure for the determination of trichothecenes in various cereals is described. HPLC was performed with a reversed-phase (C18) column eluted with methanol:water (60:40, v/v). Compounds were detected with a refractive index detector. The elution patterns of free and contaminated samples were compared. The recovery of added T-2 toxin (2 and 5 micrograms/g) in rye and wheat was approximately 80%. The application of this method allows for combined use with other sensitive methods such as mass spectrometry and gas chromatography. The described method is operationally simple, relatively inexpensive, and requires no derivatization.

Chromatography, High Pressure Liquid↗

PubMedDate not supplied

Vascular dementia: the role of cerebral infarcts.

Although vascular dementia (VaD) is the second most frequent cause of dementia after Alzheimer disease (AD), the concept remains controversial in terms of delineation. The objective of this review is to investigate, from available literature, the role of cerebral infarcts in the pathogenesis of VaD and to identify areas of interest that need further evaluation and research. The incidence of new onset dementia is increased after stroke. Stroke subtypes, total volume of cerebral infarction and functional tissue loss, and location of the lesions are probably the major determinants of VaD. Any cause of stroke can lead to VaD. In some circumstances the causal relation between stroke and dementia is clear: (1) in young patients who are unlikely to have associated Alzheimer pathology; (2) when the cognitive functioning was normal before stroke, impaired immediately after, and does not worsen over time; (3) when the lesions are located in strategic areas; and (4) when a well-defined vasculopathy known to cause dementia is proven. However, several issues remain unsolved in VaD: lack of specificity of the diagnostic criteria; influence of white matter changes and associated Alzheimer pathology; influence of preexisting cognitive status; possibility of having VaD without stroke and the clinical relevance of silent infarcts to VaD; and best therapeutic strategy to be used to prevent VaD and to prevent stroke in patients with VaD. These questions form the basis for proposals for future research.

Cerebral Infarction↗

PubMedDate not supplied

Ultrafiltration of dialysis fluid for hemodialysis.

Since the quality of water in dialysis fluid varies considerably, and, in view of the fact that endotoxin or active derivatives can cause acute side effects in patients, the dialysis fluid must be sterile. The predialyzer fluid in 20 hemodialysis patients was investigated. Bacterial loading was between 5/ml and 5,000/ml, and the endotoxin concentration was high and extremely variable. After ultrafiltration of the dialysis fluid by a polyamide hollow fiber membrane, all samples were free of bacteria, and the concentration of endotoxin was lower than the detectable limit. With this procedure we can obtain sterile dialysis fluid, which is endotoxin free.

Colony Count, Microbial↗

PubMedDate not supplied

Primary or established liver cells for a hybrid liver? Comparison of metabolic features.

It is currently in discussion whether or not established liver cell lines can be used for an extracorporeal liver assist device. Thus, metabolic features of primary hepatocytes, immortalized hepatocytes, and hepatoma cells were compared. The ability of these cells to process toxic blood of patients with hepatic failure was investigated by testing their viability in toxin enriched medium that was obtained by toxin separation from patients' blood via a molecular adsorbents recirculating system (MARS). In addition, glucose metabolism, urea synthesis, P450 dependent verapamil metabolism using high performance liquid chromatography, and interleukin-6 induced "acute phase" reaction by sulfodesoxysalicylic acid-polyacrylamide gel electrophoresis detected changes of albumin synthesis were determined in primary hepatocytes and in established liver cells. The viability of hepatoma cells after contact with the toxic compounds coming from the patients' blood was significantly decreased in comparison to that of immortalized hepatocytes and primary hepatocytes. Immortalized hepatocytes and hepatoma cells showed a significantly higher consumption of glucose associated with a significantly higher lactate synthesis. A basic urea synthesis rate could be measured in immortalized hepatocytes and hepatoma cells, but it was significantly lower than that of primary cells. P450 with its subenzyme CYP2C was inducible only in primary hepatocytes and in immortalized cells, but in the latter the enzymatic activity was lower than that of primary cells. The incubation with acute phase mediators resulted in a decrease of albumin synthesis in primary hepatocytes and in hepatoma cells, but it increased the albumin synthesis in immortalized hepatocytes. Summarizing these data, partially beneficial effects can be assumed if established cells are used in an extracorporeal liver assist device. These might include synthesis of some compounds and basic metabolic activities, such as urea synthesis. However, established liver cells showed clearly altered metabolic characteristics. The sufficient removal of toxic compounds requires additional strategies for detoxification by primary hepatocytes in sufficient amounts.

Acute-Phase Reaction↗

PubMedDate not supplied

Neutron and gamma spectroscopy for clinical dosimetry.

Neutron and photon energy spectra were measured in different depths and lateral positions in tissue-equivalent phantoms exposed to a therapeutical 14.1 MeV neutron beam. Intensity weighted mass energy absorption coefficients were derived for application in ionization chamber dosimetry in mixed neutron-gamma fields. The resulting relative depth doses show that on the beam axis for depths in excess of 20 cm, gamma radiation contributes with more than 10% to the total dose; off the axis outside the direct beam neutron and gamma doses are comparable. The differences between these doses and those neglecting the spectra distribution increase with depth and with the distance from the beam axis.

Gamma Rays↗

PubMedDate not supplied

Component evaluation of event size spectra for a clinical 14-MeV neutron beam.

Microdosimetric investigations were performed in a solid TE phantom at the DT-neutron generator at Hamburg-Eppendorf. Event size spectra were measured at different depths on the axis of a 10 X 10 cm2 field and at different lateral positions at a constant depth. Additionally, the microdosimetric spectrum of a 60Co source was determined. From radiobiological measurements the relative biological effectiveness (RBE) of crypt stem cells of mice was estimated as a function of lineal energy. The measured microdosimetric spectra are folded with this RBE function so that RBE values at different positions in the phantom were obtained. The predicted change of the RBE inside and outside the useful beam of a 10 X 10 cm2 field is shown. Contributions to the RBE dose from the various charged particle components are analyzed separately.

Humans↗

PubMedDate not supplied

Dosimetric investigations in the dose buildup using bolus techniques for fast neutron therapy.

A moulded bolus is commonly used to compensate for contour irregularities of patients treated with fast neutrons. The bolus material should have the same attenuation characteristics as tissue, should be easily mouldable and sufficiently solid for multiple applications. For fast neutron beams, the mixture of equal parts of beeswax and paraffin is a suitable bolus material. As in photon beams the bolus, when placed directly on the patient skin, removes completely the skin sparing effect. However, in neutron beams the dose buildup can mostly be recovered by lining the bolus surface in contact with the patient with a thin layer of lead. This paper presents dosimetric investigations in the dose buildup of a collimated 14-MeV DT-neutron beam underneath the surface of a solid phantom behind a 1.0-cm layer of bolus material lined with 0.03 cm of lead. It is shown that most of the dose buildup of the bolus-free neutron beam can be recovered.

Cobalt Radioisotopes↗

PubMedDate not supplied

Modelling of components of the human middle ear and simulation of their dynamic behaviour.

In order to get a better insight into the function of the human middle ear it is necessary to simulate its dynamic behaviour by means of the finite-element method. Three-dimensional measurements of the surfaces of the tympanic membrane and of the auditory ossicles malleus, incus and stapes are carried out and geometrical models are created. On the basis of these data, finite-element models are constructed and the dynamic behaviour of the combinations tympanic membrane with malleus in its elastic suspensions and stapes with annular ligament is simulated. Natural frequencies and mode shapes are computed by modal analysis. These investigations showed that the ossicles can be treated as rigid bodies only in a restricted frequency range from 0 to 3.5 kHz.

Computer Simulation↗

PubMedDate not supplied

Prospective study on the complication rate of carotid surgery.

BACKGROUND: Randomized trials of carotid endarterectomy for high-grade stenosis have shown a benefit for surgery under the condition of low perioperative complication rates. Concerns have been expressed that the complication rates of carotid surgery are higher in everyday practice and may vary considerably between centers. We prospectively established the complication rate for carotid surgery in a single institution. DESIGN: Prospective 2-year study. All patients received pre- and postoperative neurological evaluation. Laboratory tests included pre- and postoperative brain imaging, intracranial and neck vessel sonography, conventional angiography, magnetic resonance angiography, and intraoperative monitoring. PARTICIPANTS: 108 consecutive patients: 54 symptomatic patients fulfilling the inclusion criteria of the European Carotid Surgery Trial (ECST) and 54 asymptomatic patients fulfilling the inclusion criteria of the North American Trial on Asymptomatic Stenoses (ACAS). SETTING: Single academic center with a high volume of carotid endarterectomies (>50 per year). Participating center in ECST. MAIN OUTCOME MEASURES: Stroke or death as defined in the randomized trials. RESULTS: The overall complication rate was 8.3% (95% CI 4.1-15.6%). Complications were more frequent in patients with symptomatic stenosis (11.1%, CI 4.6-23.3%) than in asymptomatic cases (5.6%, CI 1.5-16.4%). Three patients died (2 strokes, 1 myocardial infarction). Disabling strokes were found in 2 patients (Rankin scale scores 3 and 4). Nondisabling strokes (Rankin scale score 1 and 2) occurred in 4 patients. The complication rates for symptomatic and asymptomatic patients were higher than the ones reported in the randomized trials, but 95% confidence intervals showed that the differences were not statistically significant. The point estimates of complication rates still supported a benefit of surgery for patients with symptomatic stenosis, but denied a positive effect of endarterectomy for patients with asymptomatic stenosis. CONCLUSION: In this center, a beneficial effect of carotid surgery for asymptomatic stenoses cannot be safely assumed.

Adult↗

PubMedDate not supplied

CASCADE: a European collaborative study on vascular determinants of brain lesions. Study design and objectives.

Dementia is a highly prevalent disease that may have a cardiovascular component. White matter lesions and brain atrophy (brain abnormalities) are prevalent in dementia cases and might form part of the anatomical basis for the disease. We designed a multi-centre study, CASCADE (Cardiovascular Determinants of Dementia), to examine long-term (10-20 years) and short-term (5 years) cardiovascular risk factors for, and the cognitive consequence of, brain abnormalities. White matter lesions and atrophy are measured with magnetic resonance imaging. Cognitive function is measured with nine tests of memory and executive function. The studies included in CASCADE were ongoing and geographically spread throughout Europe to capture the cardiovascular risk gradient. In each study, a random sample of at least 100 subjects aged 65-75 years was selected who participated in the previous research examinations conducted by the respective centres. The objectives and design of the CASCADE project are described.

Aged↗

PubMedDate not supplied

Toxicological investigations in the semiconductor industry: III: Studies on prenatal toxicity caused by waste products from aluminum plasma etching processes.

The prenatal toxic effects of contaminated vacuum pump oil (Sample A) and solid waste products (Samples B and C) originating from aluminum plasma etching processes in semiconductor manufacturing were investigated. Three strains of pregnant mice with different degrees of sensitivity during organogenesis (days 6-15 of gestation) were treated daily with 1000 mglkg b.w. (Sample A), 500 or 750 mg/kg b.w. (Sample B), and 250, 500, or 750 mg/kg b.w. (Sample C). On day 18 of pregnancy, the animals were killed and examined for gross changes, number and weight of live fetuses, as well as the number of postimplantation losses and malformations. Analytical data showed that the investigated wastes contained various halogenated hydrocarbons and inorganic compounds. Sample A revealed no signs of prenatal toxic action. In contrast, administration of Samples B and C caused strong prenatal toxic effects. The number of live fetuses declined in a dose--related manner, and evidence of intrauterine growth retardation was noted in fetuses that survived to day 18. The number of fetuses with malformations (only cleft palates) rose significantly in accordance with the doses and sensitivity of the strains (> 95 % of the fetuses of the most sensitive strain after 750 mg/kg; 85% after 500 mg/kg).

Aluminum↗