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Biomedical subjects

W Klein

Publications and source records attributed to W Klein.

At least 73 records · Page 4Linked to original sources
PubMed2001

[Angiotensin I receptor blockers for heart failure].

Angiotensin conversion enzyme inhibitors (ACE-inhibitors) have long been the only possibility to influence the renin angiotensin system (RAS) and its often fatal influences in heart failure. In the last few years specific blockers of the angiotensin 1 receptor (AT I blockers) offered a new possibility for this therapeutic target. In contrast to ACE inhibitors AT I blockers are relatively new and, therefore, few data on heart failure are available. The first head-to-head studies that compared AT I blockers and ACE-inhibitors and their effect on mortality did not show a reduced mortality in the AT I blocker groups. Based on the available data AT I blockers should be used in heart failure patients who are intolerant of ACE-inhibitors.

Angiotensin Receptor Antagonists↗
PubMed2000

Molecular characterization of the transition state regulator AbrB from Bacillus stearothermophilus.

The Bacillus subtilis transition state regulator AbrB(su) is a DNA-binding protein that acts on several genes either as activator, repressor, or preventer. However, among genes under its control, neither common binding sites could be identified nor could the structural features of this broad and specific interaction be elucidated. Attempts to elucidate these interesting features by crystallizing AbrB(su) have failed so far. Therefore, to solve this problem, we focused in this work on identifying an AbrB(su) homologue from Bacillus stearothermophilus. Using a novel method, the entire abrB(st) gene of B. stearothermophilus was cloned and sequenced. The gene encodes a 95 amino acid protein that shows 77% identity and 85% similarity to the mesophilic B. subtilis protein. A calmodulin binding peptide-tagged fusion of the thermophilic gene was constructed for overexpression and efficient affinity column purification of the AbrB(st) protein. The purified protein showed, after removal of the tag, an oligomerization behavior through hexamer formation that is essential for its DNA binding activity.

Amino Acid Sequence↗
PubMed2000

Clusters and fluctuations at mean-field critical points and spinodals

We show that the structure of the fluctuations close to spinodals and mean-field critical points is qualitatively different from the structure close to non-mean-field critical points. This difference has important implications for many areas including the formation of glasses in supercooled liquids. In particular, the divergence of the measured static structure function in near-mean-field systems close to the glass transition is suppressed relative to the mean-field prediction in systems for which a spatial symmetry is broken.

Journal Article↗
PubMed2000

Segmental degradation of left ventricular wall motion after persistent coronary fistula in a posttransplantation patient: a case report and short review of literature.

A 50-year-old man received an orthotopic heart transplant because of severe coronary heart disease and congestive heart failure. Two years after the transplantation, a continuous murmur occurred at the left sternal edge after repeated endomyocardial biopsies. Echocardiography and coronary angiography revealed a dilated left anterior descending artery with a fistula to the right ventricle. The circumflex was large with an equally postero-lateral branch, and the right coronary artery was rather small with collaterals to the distal part of the left anterior descending branch. The patient had refused any intervention to close the fistula. The left ventricular levogram was normal. Two years later, in a follow-up angiogram, the left ventricular ejection fraction had decreased as a result of hypo- and akinesis of the apex and posterior wall. We suggest that this local wall motion disturbance derives from a steal phenomenon rather than being a sequela of rejection. The decrease in left ventricular ejection fraction was associated with shortness of breath upon moderate exercise. Standard heart failure medication relieved the patient's symptoms. The observation of local wall motion disturbances in this case, as well as conflicting views in the literature, raises the question whether postbiopsy coronary fistulas in transplant patients should be closed.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed2000

The IL-10 gene is not involved in the predisposition to inflammatory bowel disease.

Although genetic predisposition for inflammatory bowel disease (IBD) is well established, little is known about the accountable genes. The pathogenesis of IBD is characterized by an imbalanced activation of Th1- and Th2-lymphocytes. IL-10 represents an anti-inflammatory cytokine which downregulates the production of Th1-derived cytokines. To evaluate the role of the IL-10 gene in IBD, two polymorphisms in the promoter region (G/A at position -1082 and C/A at position -592) were genotyped in 142 patients with Crohn's disease (CD), 104 patients with ulcerative colitis (UC), and 400 healthy controls. Significant differences were not apparent, neither in the allele frequencies of either polymorphism, nor in the haplotype frequencies. Screening of the coding region of the IL-10 gene by polymerase chain reaction--single strand conformation polymorphism (PCR-SSCP) analysis revealed a rare sequence variation in exon 1 leading to an amino acid exchange (G-->A; G15R) in two patients with CD and five healthy controls. Therefore, polymorphisms of the IL-10 gene are not demonstrably involved in the predisposition of IBD in our cohorts of patients.

Colitis, Ulcerative↗
PubMed2000

Reduction techniques in distal radius fractures.

External skeletal fixation is an important minimal invasive procedure in the management of fractures at the distal end of the radius. Attention to detail is important not only in the recognition of indications and function of the external fixator but also in its specific application. To improve anatomical restoration (e.g. palmar tilt) multi-planar ligamentotaxis is recommended. The demonstrated dynamic fixator is easy to apply and the double ball joint facilitates reduction after mounting by multi-planar ligamentotaxis. This transarticular unilateral external fixation system permits restoration of anatomy with the wrist in neutral or extension, thereby allowing full flexion of the metacarpophalangeal joints, with fingers and wrist extensor tendons relatively relaxed. Multi-planar ligamentotaxis, combined with a limited approach for supplementary procedures (fixation of articular fragments and/or bone grafting) and with early wrist motion, offers an encouraging treatment option in the management of unstable distal radial fractures by providing better anatomical restoration, especially of the palmar tilt and reduces the risk of wrist and finger stiffness.

Adult↗
PubMed2000

Results of transarticular fixator application in distal radius fractures.

From January 1989 until October 1993, 102 patients with 103 distal radius fractures were included in a prospective study with the Pennig wrist fixator (Orthofix, Srl, Italy). 90.5% of these patients were reviewed with a minimum follow-up of 12 months. Using the functional outcome score according to Gartland and Werley, we obtained 41% excellent, 46% good, 10% fair and 3% poor results. Additional procedures such as K-wires, bone grafting or radio-ulnar stabilizations were carried out in 61% of cases. The complications included five fixator displacements, four of which happened with the prototype used until the first half of 1990. Two major pin-track-infections required surgical intervention, three patients in the beginning of the series encountered irritations of the superficial radial nerve, one pin cut out of the second metacarpal bone and one patient sustained algodystrophy. The results show the significance of an anatomical reduction, the restoration of the radial length seems to be of special importance to obtain good functional outcome. This can not always be achieved with the fixator alone; often additional procedures are required in order to obtain an anatomical joint reconstruction. The advantage of this fixator lies in its lightweight and small-size design as well as in its easy application technique and the possibility to carry out the reduction after mounting the fixator with the double ball joint centered on the fracture level and the carpus.

Adolescent↗
PubMed2000

Comparison of wrist blood pressure measurement with conventional sphygmomanometry at a cardiology outpatient clinic.

OBJECTIVE: Oscillometric measurement of blood pressure at the wrist is becoming a widely used method for detection of hypertension and its control by treatment. The objective of the present study was to evaluate accuracy and suitability of wrist measurement in a clinical routine setting. PATIENTS AND METHODS: A series of 333 consecutive patients admitted to our cardiology outpatient clinic were included. Blood pressure was measured at both upper arms according to World Health Organization-International Society of Hypertension guidelines. Oscillometric measurement was performed at the contralateral wrist simultaneously. Blood pressure readings were taken by an oscillometric device applied at the wrist ('Klock'; Industrielle Entwicklung Medizintechnik, Stolberg, Germany) and a conventional mercury sphygmomanometer applied at the upper arm. RESULTS: Seventy-eight patients were excluded due to differences in blood pressure > 5 mmHg between both upper arms or due to 'error' messages of the wrist device. The data of the remaining 255 patients (149 males; mean age, 65 +/- 13 years; range, 18-95 years) are presented. Mean conventional blood pressure was significantly lower compared with the wrist device (137 +/- 20/80 +/- 11 mmHg versus 153 +/- 28/87 +/- 18 mmHg; P < 0.001 and P < 0.001). The mean difference was 16 +/- 25/6 +/- 17 mmHg. In clinical terms, differences in blood pressure exceeding +/-20/+/-10 mmHg reflecting classification of hypertension are considered important. Measurements of 101 (40%) patients were within these limits. Systolic readings of 110 (43%) and diastolic readings of 117 patients (46%) were beyond this scope. CONCLUSION: Due to low reliability of wrist blood pressure measurement, it cannot compete with the upper arm standard procedure. If ever, it should only be used if test readings in an individual comparing wrist and upper arm measurement show differences within a range of +/-20/+/-10 mmHg.

Adolescent↗
PubMed2000

Primary diffuse leptomeningeal gliomatosis: unusual MRI with non-enhancing nodular lesions on the cerebellar surface and spinal leptomeningeal enhancement.

A 28 year old man presented with a 1 month history of symptoms of intracranial hypertension. Examination showed bilateral papilloedema and meningeal signs. Magnetic resonance imaging showed nodular lesions on the cerebellar and pontine surface and thickening of the thoracic spinal leptomeninges. Throughout the course of the disease, contrast enhancement was detected in the spinal leptomeninges but not intracranially. Primary diffuse leptomeningeal gliomatosis (PDLG) was diagnosed by biopsy and later confirmed on necropsy. The present case is remarkable for the nodular superficial cerebellar lesions and the absence of intracranial contrast enhancement of the leptomeninges.

Adult↗
PubMed1999

Short- and long-term outcomes of Wiktor stent implantation at low versus high pressures. Austrian Wiktor Stent Study Group.

A prospective, randomized, multicenter trial was conducted to evaluate whether high-pressure postdilation of the Wiktor stent provides short- and long-term benefits compared with the conventional low-pressure implantation technique. From June 1995 through May 1996, 181 patients were randomly assigned to either low-pressure (6 to 12 atm, group A, n = 94) Wiktor stent placement or to high-pressure postdilation (> or = 13 atm, group B, n = 87) after stent deployment. All patients were followed up clinically for 7 +/- 3 months, with an angiographic follow-up in 154 patients (85%). After stent implantation, neither minimal lumen diameter (MLD) nor percent diameter stenosis (%DS) differed significantly between the 2 groups (MLD, 2.8 +/- 0.5 vs 2.9 +/- 0.5 mm; %DS, 17 +/- 8% vs 16 +/- 9% for groups A and B, respectively). However, a trend toward a larger mean lumen diameter within the stent was observed in group B (3.3 +/- 0.6 vs 3.5 +/- 0.5 mm for groups A and B, respectively; difference between means 0.14 mm, 95% confidence interval -0.01 to 0.29, p = 0.08). Angiographic follow-up revealed similar MLD and %DS in both treatment groups (MLD, 2.1 +/- 0.7 vs 2.2 +/- 0.8 mm; %DS, 31 +/- 17% vs 30 +/- 24% for groups A and B, respectively, p = NS). Acute stent thrombosis occurred in 2 patients (1%) (1 patient in each group), and subacute thrombosis in 1 patient (0.6%) in group A. There was 1 death in group A, and target lesion restenosis (> or = 50% DS) was observed in 15% of patients with no differences between the groups. In conclusion, this study demonstrated favorable short- and long-term results of Wiktor stent implantation. Despite a trend toward additional initial lumen gain by high-pressure postdilation, this did not translate into a measurable improvement in long-term outcome.

Aged↗
PubMed1999

[Secondary prevention following coronary intervention. Survey of 13 intervention centers in Austria].

Risk factor control has been shown to reduce the incidence of coronary events in patients with or without preceding infarction. Secondary prevention should therefore be borne in mind by every cardiologist. In order to test this concept and/or to promote secondary prevention in our country, the following survey was conducted by our working group for epidemiology and prevention. All interventional centres of the country (7 million inhabitants) were asked to report relevant data of 50 consecutive patients with PTCA in a structured questionnaire. Thirteen centres responded and we report the data of 650 patients. The mean proportion of women was 28%, the mean age 61.1 years and the mean stent rate 49.8%. The indications for PTCA varied widely: stable angina 10-74%, unstable angina 10-86%, primary PTCA 0-22%. The risk factor history was distributed as follows: diabetes 12-46% (mean 22.3%), hypertension 32-68% (mean 54.2%), current smoking 6-56% (mean 21.9%), and total cholesterol (TChol) > 200 mg/dl: 30-78% (mean 60.3%). Current lipid values were available for T chol. in 44-100% (mean 84.5%) and for LDL in 4-100% (mean 67.1%). Dietary counselling by a dietician was done in 4-100% of patients (mean 35.6%) Information concerning the hazards of smoking was given to 25-100% (mean 83.6%) of current smokers. Drug treatment at hospital discharge was as follows: 84-100% (mean 93.1%) received ASA, 24-74% (mean 49.8%) ticlopidine, 6-84% (mean 53.3%) nitrates, 34-82% (mean 60.2%) beta blockers, 10-70% (mean 39.5%) ACE inhibitors, 4-74% (mean 4 7.2%) lipid lowering drugs, 7-48% (mean 17.8%) calcium antagonists, 0-12% (mean 6.1%) digitalis and 0-28% (mean 13.6%) diuretics. Follow-up data were collected in 4 centres at 6 months post discharge and were available for 174 patients. Here we found an increase in the prescription of calcium antagonists, digitalis and statins. The following conclusions were drawn at a conference in which all centres participated: lipid values should be available for each patient at PTCA, dietary counselling should be initiated for every patient during hospitalisation (and continued by the family physician) and the national cardiac society should promote guidelines for the use of drugs in which the variation in use is too wide at present. It should be ensured that these guidelines are implemented not only in patients after AMI but also in those after PTCA.

Adrenergic beta-Antagonists↗
PubMed1999

Management strategies in unstable coronary artery disease--current problems and future directions. The UCAD Council.

Unstable coronary artery disease continues to pose a major challenge to clinicians. The advent of new therapies, such as percutaneous transluminal coronary angioplasty, low-molecular-weight heparins, and glycoprotein IIb/IIIa inhibitors, provides new management options for this indication but also raises new questions with regard to optimal management. Prospective randomized trials with well-defined, long-term outcome measures and a means of identifying which patients will derive most benefit from each treatment, together with a means of rapid and clear dissemination of study results and implications, are required in order to advance the management of unstable coronary artery disease.

Angina, Unstable↗
PubMed1999

Subclinical health effects of environmental pesticide contamination in a developing country: cholinesterase depression in children.

The effect of exposure to pesticides among children in a Nicaraguan community in the path of rain water runoff from a large crop-dusting airport was evaluated by measuring plasma cholinesterase. Mean cholinesterase activity in 17 children in the path of runoff was 2.4 international units/ml blood/min, lower than the 2.9 IU/ml/min measured in a group of 43 children from an unexposed community (difference=0.49 IU/ml/min; 95% C.I. 0.24, 0.76). Six (35%) of the 17 exposed children had abnormally low cholinesterase levels. A possible explanation for this physiological effect of exposure to pesticides is the dermal absorption which may have occurred among children playing barefoot in puddles grossly contaminated by runoff from the airport. Drinking water from a well in the exposed community demonstrated low level residues of cholinesterase-inhibiting pesticides, although contamination with toxaphene (not a cholinesterase inhibitor) exceeded by over 8-fold the United States Environmental Protection Agency maximum permissible concentration in drinking water. The difficulty in measuring health effects resulting from environmental pesticide contamination, and in controlling exposure resulting from the rapidly increasing use of pesticides, is a growing problem for developing countries like Nicaragua.

Child↗
PubMed1999

Metabolism of trans fatty acids by hepatocytes.

The present work was undertaken to study the metabolism of fatty acids with trans double bonds by rat hepatocytes. In liver mitochondria, elaidoyl-CoA was a poorer substrate for carnitine palmitoyltransferase I (CPT-I) than oleoyl-CoA. Likewise, incubation of hepatocytes with oleic acid produced a more pronounced stimulation of CPT-I than incubation with trans fatty acids. This was not due to a differential effect of cis and trans fatty acids on acetyl-CoA carboxylase (ACC) activity and malonyl-CoA levels. Elaidic acid was metabolized by hepatocytes at a higher rate than oleic acid. Surprisingly, compared to oleic acid, elaidic acid was a better substrate for mitochondrial and, especially, peroxisomal oxidation, but a poorer substrate for cellular and very low density lipoprotein triacylglycerol synthesis. Results thus show that trans fatty acids are preferentially oxidized by hepatic peroxisomes, and that the ACC/malonyl-CoA/CPT-I system for coordinate control of fatty acid metabolism is not responsible for the distinct hepatic utilization of cis and trans fatty acids.

Acetyl-CoA Carboxylase↗
PubMed1999

The effects of eccentric head positions on leftward and rightward turns of a handle-bar.

We explored the structural constraints on concurrent movements and/or positions of the head and a steering device by means of a reaction-time task. In the first experiment, subjects had to respond rapidly to an imperative stimulus by way of rotating a handle-bar to the left or to the right and back to the central position while they maintained a left or right eccentric position of the head. Latency of the handle-bar responses did not depend on whether their initial directions were toward the eccentric head position or in the opposite direction, but kinematic characteristics did: iso-directional movements were of larger amplitude and longer duration until peak excursion. In the second experiment, the imperative stimuli for handle-bar rotations were presented at variable intervals after the head had been moved from the central to one of the eccentric positions and before its predictable return movement. Kinematic characteristics of the handle-bar rotations depended on the left and right eccentric head positions in the same way as in Experiment 1, but now iso-directional movements had a longer reaction time than movements in the direction of the forthcoming return movement of the head. These findings suggest that specifications of head-movement directions facilitate concurrent specifications of handle-bar rotations in the same direction and inhibit specifications of handle-bar rotations in the opposite direction, consistent with the notion of cross-talk during motor programming.

Adult↗