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W J Schnedl

Publications and source records attributed to W J Schnedl.

At least 19 recordsLinked to original sources
PubMed2002

Silent haemoglobin variants and determination of HbA(1c) with the HPLC Bio-Rad Variant II.

AIMS: To evaluate the determination of HbA(1c) with an automated high performance liquid chromatography (HPLC) method in patients with clinically silent haemoglobin variants. METHODS: HbA(1c) values were determined with the ion exchange HPL Bio-Rad Variant II using the high resolution beta thalassaemia programme in patients with silent haemoglobin variants, namely: Hb Graz, Hb Sherwood Forest, Hb O Padova, and Hb D. RESULTS: All of these haemoglobin variants caused additional peaks in the chromatograms. No clinically useful HbA(1c) results were produced for patients with Hb Graz and Hb Sherwood Forest, the results for the patient with Hb D were too low, but the results for patients with Hb O Padova were acceptable. CONCLUSIONS: The development of this automated HPLC method modification with high resolution mode aids the identification of interference caused by the described clinically silent haemoglobin variants in HbA(1c) determination.

Artifacts↗
PubMed2001

Oxidative stress during peripheral angioplasty. Implication for late restenosis?

BACKGROUND: Percutaneous transluminal angioplasty (PTA) is routine treatment for patients with peripheral arterial disease (PAD). The procedure induces local generation of reactive oxygen species (ROS), such as H2O2. Since these have been shown to stimulate vascular smooth muscle cell growth (VSMCG), we investigated peroxide levels in patients with PAD during PTA and related these results to late clinical outcome. METHODS: Thirty patients (17 male, 13 female, 20 Fontain stage II, 10 Fontaine stage IV, median age 68 years) undergoing PTA of a 2-6 cm stenosis of the femoral or popliteal artery were included. The procedure was performed successfully in all patients. At follow-up six months thereafter restenosis was evaluated by duplex sonography. Total peroxide concentrations were determined in plasma drawn before, 6, 24 and 48 hours after the procedure by the Operoxide activityO assay, which is based on the reaction of horseradish peroxidase with plasma peroxides, using tetramethylbenzidine as the chromogenic substrate. RESULTS: The median peroxide level before angioplasty was 280 mmol/L (range 47-549). Levels were higher in patients with advanced disease, in smokers and in patients with diabetes. In response to angioplasty, peroxide levels increased within 48 hours (p<0.001). Six months after the procedure, restenosis was observed in 10/30 (33 percent) of patients. Clinical outcome was not dependent upon baseline or postinterventional peroxide levels. CONCLUSIONS: Elevated peroxide levels are seen in patients with advanced arteriosclerotic disease and in those with diabetes, but are not predictive for late restenosis.

Aged↗
PubMed2001

Predicting the risk of restenosis after angioplasty in patients with peripheral arterial disease.

Restenosis is a serious therapeutic problem after percutaneous transluminal angioplasty (PTA). Strategies for the prevention of late restenosis include the use of antiaggregatory and anticoagulant drugs, aggressive lipid-lowering, intravascular radiation and others. As some of these therapeutic options are not without side effects it is important to identify patients with an increased risk to develop restenosis. Major clinically recognizable risk factors for restenosis are advanced disease stage and female gender. Elevated plasma levels of fibrinogen, Lp(a), CRP, and migration-inducing activity appear to indicate an unfavorable clinical outcome, and so does post-interventional increase of vWF and PAI-1 antigen. For peripheral arterial disease, only one study has addressed the influence of homocysteine levels upon the restenosis rate after PTA. Although homocysteine levels were elevated in >50% of patients at entry, they were not associated with a higher restenosis rate. Currently the available data allow a rough approximation of a patient's individual risk.

Angioplasty, Balloon, Coronary↗
PubMed2000

Effects of postprandial walking on delayed gastric emptying and intragastric meal distribution in longstanding diabetics.

OBJECTIVE: We investigated the influence of standardized postprandial walking on the rates of gastric emptying and of intragastric meal distribution in 50 consecutive patients with longstanding insulin-dependent diabetes mellitus. METHODS: Gastric emptying of a semisolid meal labeled with 99mTc was continuously recorded with a dual-head gamma camera with patients in the supine position for 90 min before and 20 min after a 30-min postprandial walk. Regions of interest enclosing total stomach, and proximal and distal gastric compartments were calculated to determine gastric emptying rates and intragastric meal distribution. RESULTS: The evaluation of gastric emptying rates before and after postprandial walking demonstrated two variants of delayed gastric emptying: one variant that was counteracted by postprandial walking in seven patients (14%, Group I) and another variant that was not influenced by postprandial walking in 11 patients (22%, Group II). In addition, the emptying rates of 28 patients (56%) were within the range of controls and in four patients the emptying was accelerated (8%). The filling of the proximal gastric compartment was predominant and remained dominant after walking in Groups I and II. In controls and in diabetics with normal gastric emptying, the preliminary predominant filling of the proximal compartment was equalized after walking and the proximal compartment regained predominance thereafter. The changes in gastric emptying characteristics from delayed to accelerated gastric emptying may be related to the duration of diabetes (r = -0.47, p<0.03) and were not indicated by symptoms of upper GI discomfort or by secondary diabetic manifestations. CONCLUSION: Postprandial walking may improve gastric emptying in 14% of patients with longstanding insulin-dependent diabetes mellitus.

Adult↗
PubMed2000

Scintigraphic long-term follow-up of a patient with metastatic glucagonoma.

Two years after resection of a pancreatic glucagonoma, scintigraphy with 111indium-labeled octreotide revealed hepatic metastases in a 48-yr-old man. Hepatic metastases were also visualized by CT, whereas an additional lesion in the chest was seen only by scintigraphy. A total of 11 follow-up examinations over 46 months proved somatostatin receptor scintigraphy to monitor reliably somatostatin receptor expression, growth and dissemination of glucagonoma metastases, and to indicate therapeutic readjustment if necessary. The survival time of the patient is now >75 months, in comparison with a mean survival time of 59 months reported for metastatic glucagonoma.

Follow-Up Studies↗
PubMed2000

Evaluation of HbA1c determination methods in patients with hemoglobinopathies.

OBJECTIVE: To evaluate commercially available determination methods for HbA1c in patients with hemoglobin variants. RESEARCH DESIGN AND METHODS: HbA1c values were determined with various commercially available methods, including ion-exchange high-performance liquid chromatography (HPLC), boronate affinity assay, and immunoagglutination in patients with the hemoglobin mutations Hb Graz, Hb Sherwood Forest, Hb O Padova, Hb D, and Hb S. RESULTS: The effect of hemoglobinopathies on glycohemoglobin measurements was highly method dependent. The HPLC methods for HbA1c determination lacked the resolution necessary to differentiate hemoglobin variants. They demonstrated additional peaks in the chromatograms and HbA1c results either too low or too high compared with the nondiabetic reference range. With all immunoassays, Hb Graz demonstrated falsely low values. The other hemoglobinopathies in our study caused falsely low and/or high HbA1c results in immunoagglutination methods. The boronate affinity method showed values in an acceptable range for all hemoglobin variants. CONCLUSIONS: Because of the local occurrence of Hb variants and the ethnic origin of a given population, every individual laboratory must establish and validate its own assay method. In managing diabetic patients, knowledge of hemoglobinopathies influencing HbA1c determination methods is essential because hemoglobin variants could cause mismanagement of diabetes resulting from false HbA1c determinations.

Biomarkers↗
PubMed2000

Smooth muscle cell migration promoting activity of plasma predicts restenosis in patients with peripheral arterial occlusive disease undergoing angioplasty.

BACKGROUND: Efficacy of percutaneous transluminal angioplasty (PTA) is limited by restenosis occurring in a large proportion of patients. Smooth muscle cell (SMC) migration is a major pathomechanism of restenosis. We studied SMC migration inducing activity of plasma from patients with peripheral arterial occlusive disease (PAOD) undergoing PTA. METHODS AND RESULTS: SMC migration was determined in a two-dimensional assay system after addition of 1/25 plasma dilutions. Mean increase in migration area was 65.5 +/- 33.8% in normal controls and 67.7 +/- 53.2% in patients with PAOD. 6 hours after PTA, plasmatic migration inducing activity was largely unchanged. In 19/30 patients with restenosis (6 months after PTA) migration promoting activity (82.7 +/- 60.0) was significantly higher than in 11/30 patients with patent vessels (41.8 +/- 21.0; p = 0.03). No correlation of clinical risk factors with outcome was observed. A weak correlation was found between plasmatic migration promoting activity and levels of epidermal growth factor and transforming growth factor-beta. CONCLUSION: The capacity of human plasma to stimulate SMC migration in tissue culture can be used to assess the risk for restenosis after PTA in patients with PAOD.

Aged↗
PubMed1999

[Development of insulinoma cells as therapy in insulin-dependent diabetes mellitus].

In healthy persons insulin secreting beta-cells of the pancreas regulate blood glucose levels within a narrow physiological range. Since the detection of insulin in 1922 by Banting and Best, subcutaneous insulin replacement has remained the sole treatment modality for insulin-dependent diabetes mellitus (IDDM). However, even trained patients undergoing intensive insulin therapy fail to achieve normal function of the pancreatic beta-cells. One approach to solve this problem is pancreas and islet cell transplantation. Because of technical problems, limited number of transplantable organs and toxicity of immunosuppressive therapy, both are still in an experimental state. An alternative approach is the development of genetically modified insulin secreting cell lines for replacement of islet cells. So far, experiments support the expectation to develop genetically manipulated cell lines who imitate the function of islet beta-cells and are protected from the immune response. The ultimate goal is the development of an engineered human beta-cell line and, after animal experiments, to use it for treatment of patients with IDDM.

Animals↗
PubMed1999

Bone scintigraphy and magnetic resonance imaging in adult-onset Still's disease.

Adult-onset Still's disease (AOSD) is an acute systemic inflammatory disorder of unknown origin. We report a patient whose AOSD presented with the commonly accepted diagnostic clinical signs and laboratory parameters. The painful joints distinctly demonstrated increased uptake of 99mTc-methylene diphosphonate in scintigraphy and areas of increased gadolinium-enhanced signal in MRI. Biopsies indicated bone marrow edema. AOSD in association with bone marrow edema had not been previously demonstrated. AOSD is often diagnosed after a considerable delay, bone scintigraphy, and magnetic resonance imaging may offer new imaging techniques for early diagnosis and successful therapy in follow-up examinations.

Adult↗