Biomedical subjects
Publications and source records attributed to W Richter.
Explore the source record for details and available documents.
The aim of this paper is to generate data on the prevalence of inflammatory arthritis in different subgroups of the population and to identify correlates on the basis of population-based cross-sectional data: the "First National Health Survey of the Federal Republic of Germany". This Survey investigated the prevalence of inflammatory arthritis, comorbidity and health-relevant behaviors on the basis of interviews with physicians and medical evaluations conducted in the period from October 1997 to March 1999. The study was based on a net sample comprising 6,461 subjects aged 18-79. Our data demonstrate an overall prevalence of 3.4% for inflammatory arthritis. The prevalence of inflammatory arthritis is significantly higher in women, the over-50, lower-income groups, and habitual smokers. Patients with inflammatory arthritis have a higher rate of numerous comorbidities such as osteoporosis, thyroid disease, chronic bronchial disease, hypertension, and elevated blood lipids versus healthy reference groups.
Explore the source record for details and available documents.
The in vitro stability of archaeosomes made from novel synthetic membrane-spanning tetraether lipids was evaluated in conditions mimicking those of oral route application in terms of bile salts, serum and low pH..
Mitogens of the TGF-beta superfamily have been shown to be crucial local and systemic regulatory molecules involved in fracture healing. However, there exists only little information about systemic regulation of bone regeneration by growth factors and no reports comparing serum levels of bone growth factors between normal and failed fracture healing have been published so far. We hypothesized that quality of fracture healing might be reflected by systemic alterations of key regulatory growth factors involved in bone formation and remodeling. Therefore, the aim of this study was to evaluate possible differences in serum levels of BMP-2, BMP-4, and TGF-beta1 in patients with normal and delayed fracture healing. 103 patients with diaphyseal fractures of long bones were recruited prospectively. Peripheral blood samples were collected over a period of 6 months following a standardized time schedule. At the end of the individual investigation period, growth factor serum levels were measured using commercially available enzyme immunoassays. For the elimination of disturbing influences, patients in both groups were matched by gender, age, fracture type, and localization as well as applied technique of osteosynthesis. During a study period of 1 year, 10 patients with an atrophic type of delayed union could be retrieved and matched to 10 patients with normal fracture healing. The diagnosis of delayed union was assumed in case of failed consolidation 4 months after trauma. We found an increase of TGF-beta1 serum levels up to 2 weeks after fracture in both groups with a following return to the reference value within 6 weeks after trauma. However, decline of serum concentration occurred earlier in patients with delayed fracture healing. At 4 weeks after trauma, serum levels of TGF-beta1 were significantly lower in patients of the delayed union group. Serum levels of BMP-2 and BMP-4 were below detection level in all patients, respectively. These findings support the critical role of TGF-beta1 in fracture healing. Events during the consolidation phase seem to be dependent on sufficient availability of TGF-beta1.
Explore the source record for details and available documents.
BACKGROUND: The purpose of the paper was to generate up-to-date, representative osteoarthritis prevalence data for individual population subgroups and to identify potential risk factors. MATERIAL AND METHODS: A cross-sectional study, the "First National Health Survey", investigated the prevalence of osteoarthritis, comorbidity and health-relevant behaviours of the post-unification German population on the basis of interviews with physicians and medical evaluations conducted in the period from October 1997 to March 1990. The study was based on a net sample comprising 6205 subjects aged 18-79 years. RESULTS: The three main correlates for osteoarthritis are age, obesity and occupational stress factors. Osteoarthritis patients are more likely to have osteoporosis, thyroid disease, chronic bronchial disease, hypertension and elevated blood lipids, but do not tend to have a higher incidence of diabetes. CONCLUSION: Our data show the importance of preventive behavioural approaches such as weight management and workplaces designed to limit joint overuse.
BACKGROUND: The severity of pain from musculoskeletal disorders might be associated with high sensitivity C reactive protein (hsCRP), a sensitive marker of low grade systemic inflammation. OBJECTIVE: To study the association between pain as assessed by a visual analogue scale (VAS) and hsCRP in patients with chronic low back pain and acute sciatic pain. METHODS: Information on pain severity, determinants of hsCRP, and hsCRP values were obtained prospectively at up to 10 time points during six months in 72 consecutive patients (mean age 43.3 years; 59.7% female): 41 with chronic low back pain and 31 with acute sciatic pain. The association between severity of pain and raised (highest quartile) hsCRP values at any time point was estimated by multivariable logistic regression using generalised estimating equations to adjust odds ratios (OR) and their confidence intervals (CI) for intraindividual dependence of measurements. RESULTS: Mean intensity of pain (VAS 0-10) at baseline was 4.9 and 5.5 in patients with chronic low back and acute sciatic pain, respectively. Highest v lowest tertile of average intensity of pain during the last 24 hours was associated with increased hsCRP levels among patients with acute sciatic pain (adjusted OR = 3.4 (95% CI, 1.1 to 10), but not in patients with chronic low back pain (adjusted OR = 0.87 (0.25 to 3.0)). CONCLUSIONS: Mean intensity of pain during the previous 24 hours as assessed by VAS was independently associated with high levels of hsCRP in patients with acute sciatic pain but not in those with chronic low back pain.
AIMS/HYPOTHESIS: Conformation-dependent autoantibodies directed against GAD65 are markers of Type 1 diabetes. In this study we aimed to determine whether the substitution of GAD65 with GAD67 amino acids would affect the binding of conformation-dependent GAD65 autoantibodies. METHODS: We used PCR-based site-directed mutagenesis to generate a series of mutated GAD65 cDNA constructs in which specific GAD65 coding sequences for regions of the protein critical for autoantibody binding were replaced with GAD67 coding sequences. RESULTS: The introduction of a point mutation at position 517, substituting glutamic acid with proline, markedly reduced the binding of disease-associated GAD65 antibodies. The binding of GAD65 antibodies to the E517P mutant was reduced in the sera of all newly diagnosed Type 1 diabetes patients ( n=85) by a mean of 72% ( p<0.0001) compared with binding to wild-type GAD65. Patients with latent autoimmune diabetes in adults ( n=24) showed a similar reduction in binding (79% reduction, p<0.0001). First-degree relatives who subsequently progressed to Type 1 diabetes ( n=12) showed a reduction in binding of 80% compared with a reduction of only 65% among relatives who had not progressed to disease ( n=38; p=0.025). In healthy GAD65Ab-positive individuals who did not progress to diabetes during a 9-year follow-up period ( n=51), binding to GAD65-E517P was reduced by only 28% compared with binding to wild-type GAD65. CONCLUSIONS/INTERPRETATION: Differences in autoantibody binding to wild-type GAD65 versus GAD65-E517P may provide predictive information about Type 1 diabetes risk beyond that provided by the presence or absence of GAD65 autoantibodies. Lack of binding to mutant GAD65-E517P defines GAD65-positive individuals who are at higher risk of developing diabetes.
Compared to native blood vessels, all clinically available blood vessel substitutes perform suboptimally. Numerous approaches to tissue engineer (TE) blood vessels have been pursued using different scaffold materials, cell types, and culture conditions. Several limitations however remain to be overcome prior to the potential application in the arterial system. This study aimed at tissue engineering viable ovine blood vessels suitable for implantation into the systemic circulation of sheep. In recent studies vascular smooth muscle cells (vSMC) were derived by an explant technique. However, in this study we show that homogenous populations of differentiated vSMC were only obtained by enzymatic dispersion as characterized by immunostaining for specific vSMC marker proteins. In contrast the explant method yielded predominantly less differentiated myofibroblast-like cells. Enzymatically derived vSMC were seeded onto P-4-HB scaffolds and incubated either in a pulsatile flow bioreactor or under static conditions. Dynamically cultured TE blood vessel substitutes showed confluent layered tissue formation and were completely water resistant. They displayed significantly increased ECM synthesis, DNA, and protein content as well as vSMC marker expression. Mechanical properties of bioreactor cultured TE blood vessels approached those of native aorta. In conclusion ovine, aortic blood vessel substitutes were successfully created using enzymatically derived vSMC, bioabsorbable scaffolds, and applied shear stress.
OBJECTIVE: Osteoarthritis (OA) is characterized by a progressive degeneration of articular cartilage and loss of joint function. We hypothesized that degradation of articular cartilage results in increased fragmentation of collagen type II. Thus, the concentrations of degradation products of this major cartilage matrix protein may increase in body fluids of patients with OA. METHODS: Monoclonal antibodies specific for a human collagen type II C-telopeptide (CTx-II) fragment were used in an ELISA for quantification of collagen type II fragments in urine. Clinical assessment of 88 patients with advanced OA of either hip or knee and 48 age-matched controls was performed with the Harris hip score, the Merle d'Aubigné score and a knee score. Joint space narrowing and the Kellgren and Lawrence score were assessed as radiological signs of OA. RESULTS: The concentration of CTx-II was significantly higher in OA patients compared with controls (527 vs. 190 ng/mmol, p < 0.001) whether the patients were diagnosed with hip OA (n = 51) or knee OA (n = 37). Mean CTx-II levels were higher in hip OA than in knee OA and a slight increase in levels with age was observed in the controls, but not in OA subjects. CONCLUSION: Elevation of CTx-II in urine of patients with severe OA compared with a control group suggests that collagen type II derived fragments may serve as markers for OA.
Visible and UV light spectra display striking differences in optical reflectivity for the two types of monatomic steps on copper (111) surfaces. Electronic structure calculations trace these differences to the specific contributions of p(axially) and p(radially) local densities of states, parallel and perpendicular to the steps, of the distinctly coordinated corner atoms. The local origin of the spectral reflectance anisotropy is further corroborated by experiments on Cu(111) surfaces with varying step densities. Site specificity of the electronic structure of atoms in low coordinated sites on Cu(111) vicinals is thus revealed by reflectance anisotropy spectroscopy which can thereby detect step atom densities down to 10(13) atoms/cm(2).
The InP(001)(2 x 1) surface has been reported to consist of a semiconducting monolayer of buckled phosphorus dimers. This apparent violation of the electron counting principle was explained by effects of strong electron correlation. Combining first-principles calculations with reflectance anisotropy spectroscopy and LEED experiments, we find that the (2 x 1) reconstruction is not at all a clean surface: it is induced by hydrogen adsorbed in an alternating sequence on the buckled P dimers. Thus, the microscopic structure of the InP growth plane relevant to standard gas phase epitaxy conditions is resolved and shown to obey the electron counting rule.
Charged phospholipids and mixtures of charged phospholipids with zwitterionic lipids were adsorbed onto polyelectrolyte capsules templated on erythrocytes. The assembly was proved by means of electrophoretic mobility measurements, confocal laser scanning microscopy and flow cytometry. Freeze-fracture electron microscopy proved that the phospholipids assemble as bilayers or multilayers. Single particle light scattering showed that bilayers composed of anionic lipids can be intercalated between subsequent polyelectrolyte inter-layers in a regular manner. Neutral lipids can form multilayers. A pronounced decrease in capsule permeability for small polar dyes upon lipid adsorption was followed by confocal laser scanning microscopy.
Pain specialists are often involved in assessing social medical aspects of chronic pain patients. A standardized examination in the assessment process is not published. Data and statements on the assessment process between 1993 and 1997 were recorded from 15 experts by questionnaire. Statements to 568 reports were made. The majority of performance impairments were caused by back pain (35.9%) and headache (19.3%). All examiners integrated a psychological assessment. Although the assessment processes were very different, all examiners fulfilled the minimal criteria of the presented process for assessment of chronic pain patients. Verifying the symptoms as well as capturing some aspects of aggravation proved to be problematic. The present assessment practice is discussed with regard to the unequal procedure. On basis of the received data and the own experience in examination the process of structured assessment of chronic pain patients is presented under medical and psychological aspects. It contains a recommendation of a standardized process with minimal criteria and an optional supplement of the standardized process with problematical patients (e.g.demonstration, aggravation, simulation). Minimal demands on a qualified assessment of chronic pain patients should contain the study of the history, the German Pain-Questionnaire, the analysis of all the painful complaints with weighting their importance, the examination and the basic registration of sensational, emotional, cognitive, behavioral and social aspects of the chronic pain syndrome. An appended glossary of the most usable psychological tests with comments on their validation criteria aims to provide a more standard multimodal assessment of chronic pain patients complaints and functionability.
The purpose of this work was to develop and to characterize hydrophilic gels containing nanocapsules (NC) of diclofenac (DIC). Nanocapsules suspension of poly-epsilon-caprolactone containing free acid diclofenac were prepared by nanoprecipitation. The pH value of the nanocapsules suspension was 5.70 +/- 0.03 and the mean sizes of the NC were in the sub 300 nm range. Drug incorporated into the nanocapsules was close to 100% and the encapsulation efficiency was 104.1% +/- 3.5%. Diclofenac nanocapsules suspension (1 mg/mL) was incorporated in a Carbopol gel matrix fournishing a formulation with 0.5 mg of DIC/g. The gel stability was evaluated in terms of the macroscopic and microscopic aspect, rheological properties, pH and drug recoveries. As a result, we obtained a suitable formulation for topical use presenting a non-Newtonian behaviour with plastic properties and with intact nanostructures in the gel matrix after 3 months storage atroom temperature (freeze-fracture electron microscopy).
Tris(4-chlorophenyl)methanol (TCPM) is a by-product in the manufacture of technical grade DDT, which is known to alter properties and functions of the female reproductive system. We investigated whether in vitro TCPM has an influence on the function of gap junction-mediated intercellular communication (GJIC) and gap junction protein expression of connexin 43 (Cx43) in cultured bovine granulosa cells. GJIC was assessed by fluorescent dye microinjection (dye-coupling). After a 1-h exposure to TCPM at a concentration of 32 microM, a significant (P<0.05) reduction in dye coupling occurred. The same result was obtained with o,p'-DDT. At a concentration of 32 microM both pesticides were cytotoxic as indicated by significant (P<0.05) increased propidium iodide staining of the cell nuclei. Little or no effect on the stainable pattern of connexons occurred after 1 h incubation time, while after 3 h treatment from 16 to 64 microM TCPM, a significant inhibition in the immunostaining resulted and the concentrations of 32 and 64 microM TCPM were cytotoxic for the granulosa cells. The freeze-fracture electron microscopy resulted in small differences in the morphology of gap junction plaques of cell cultures treated for 3 h with 8 or 16 microM TCPM in comparison to untreated cells. After treatment with 32 microM TCPM, gap junction plaques were very rarely detected and the lateral intramembraneous particles (IMP) distribution of many plasma membranes was strongly altered. Estimation of the cellular parameters may lead to an enhanced understanding of the mechanism of chemically induced toxicity by TCPM, that causes a general toxic effect on granulosa cells. We can conclude that TCPM is a toxic risk in the same manner as DDT.
In the search for new marker genes suitable to distinguish chondrocytes from osteoblasts and mesenchymal stem cells in culture, we have identified and characterized a novel gene called chondrocyte expressed protein-68 (CEP-68), harbouring an N-terminal leader peptide and an epidermal growth factor-like calcium-binding domain. CEP-68 defines a new family of proteins and complements collagen type II as a new marker for stem-cell-based chondrogenic tissue engineering.