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Biomedical subjects

D Nagel

Publications and source records attributed to D Nagel.

At least 37 records · Page 2Linked to original sources
PubMed1998

A mental route to motor learning: improving trajectorial kinematics through imagery training.

There are contrasting reports upon the level of effectiveness of motor imagery in learning new motor skills, but there is general consensus that motor imagery can lead to improvements in performance, especially in combination with physical practice. In the present study we examined the effectiveness of motor imagery in the acquisition of movement invariants in two grapho-motor trajectorial learning tasks with differing visuospatial components: 'Ideogram drawing' and 'connecting circles'. Two subject groups were studied: An imagery group, which underwent 10 min of motor imagery training and a control group, which practised a control visuomotor task over the same period of time. The results showed that imagery training alone enabled the subjects to achieve a significant approach to movement isochrony as well as a significant shifting of peak velocity toward the target. After a practice phase, both groups improved their performance, but the imagery group was still significantly faster than the control group. Furthermore, a series of tests measuring visual imagery abilities was administered to the subjects. There were however no significant relationships between the motor performance and the visual imagery ability levels of the subjects. It is concluded that motor imagery can improve the acquisition of the spatio-temporal patterns of grapho-motor trajectories and that there are different processes involved in visual and motor imagery.

Adult↗
PubMed1998

Validation of an automated enzyme immunoassay for Interleukin-6 for routine clinical use.

Serum levels of Interleukin-6 (IL-6), a proinflammatory cytokine, are increased in early stages of inflammatory diseases such as infection and sepsis. Assay systems which permit its measurement within a few hours and as a single measurement have not been reported so far. We therefore evaluated a now commercially available automated method for IL-6 measurement on the Cobas Core immunological analyzer (Roche Diagnostic Systems) which enables single IL-6 measurement within about 1 hour. The automated assay correlates well with an established, manual microtiter plate assay (Biosource GmbH) which uses the same antibodies and reagents (r=0.98). Accuracy of the automated method was established by adding known amounts of IL-6 international reference preparation. Recovery of the international standard was in the range of 92104%. The automated assay had a precision of singletons below 6% and was linear up to 2800 pg/ml. This automated assay provides a suitable, convenient and time saving method for measurement of IL-6 serum levels in the routine clinical laboratory.

Automation↗
PubMed1997

Aggressive lowering of fibrinogen and cholesterol in the prevention of graft vessel disease after heart transplantation.

BACKGROUND: A combined treatment of statins and extracorporeal H.E.L.P.-apheresis (Heparin-mediated Extracorporeal LDL/fibrinogen Precipitation) has already been shown to be beneficial for coronary artery disease (CAD). Presumably high levels of LDL cholesterol, Lp(a), and fibrinogen also increase the risk for graft vessel disease (GVD). Therefore, we studied whether this concept can be applied in GVD, based on the hypothesis that GVD is an accelerated form of CAD. METHODS AND RESULTS: For comparison of statin treatment alone with the combined treatment, two matched groups of 10 cardiac transplant recipients were studied during a mean period of 3.6+/-1.0 years. Both groups were comparable in clinical characteristics, immunosuppressive medication, baseline plasma Lp(a), and high fibrinogen levels. Group I had normal LDL-C levels (3.36+/-0.60 mmol/L). Simvastatin alone was administered in this group to counteract the LDL-increasing effect of the immunosuppressive medication. Group II had marked hypercholesterolemia (LDL-C, 6.07+/-1.89 mmol/L), which was treated, in addition to simvastatin, with H.E.L.P.-apheresis weekly. GVD was assessed by coronary angiography. Simvastatin alone kept LDL-C levels within baseline limits but could not prevent GVD in 7 of 10 patients. In contrast, the combined treatment prevented GVD in 9 of 10 patients (P=.006) by simultaneous and drastic reduction of 48% LDL-C (P=.006), 35% fibrinogen (P=.002), and 47% Lp(a) (P=.006) below baseline. Both treatments were well tolerated and did not affect prevention of graft rejection and infections. CONCLUSIONS: A strategy of early, drastic lowering of fibrinogen, LDL-C, and Lp(a) helps to prevent GVD.

Adult↗
PubMed1997

Simvastatin reduces graft vessel disease and mortality after heart transplantation: a four-year randomized trial.

BACKGROUND: Accelerated graft vessel disease (GVD) represents the most serious long-term complication of heart transplantation. A possible cause underlying this progressive coronary vascular disease is believed to be post-transplantation hypercholesterolemia. METHODS AND RESULTS: In a 4-year prospective randomized study with heart transplant recipients, the efficacy of primary antihypercholesterolemic therapy with simvastatin was compared with that of general dietary therapy. The aim of the treatment was to maintain post-transplantation LDL-cholesterol levels at <120 mg/dL. Seventy-two heart transplant recipients receiving standard triple immunosuppression were randomly assigned to an active-treatment group (low-cholesterol diet and simvastatin, n=35) or a control group (general dietary measures, n=37). In the course of 4 years after transplantation, the simvastatin group had significantly lower LDL-cholesterol concentrations than the control group (mean+/-SD, 115+/-14 versus 156+/-17 mg/dL,P=.002), a significantly better long-term survival (88.6% versus 70.3%,P=.05), and a lower incidence of GVD in the coronary angiographic findings (16.6% versus 42.3%,P=.045). The incidence of graft rejections did not differ between the two groups, although there was a tendency toward a lower number of serious rejections in the simvastatin group (2.8% versus 13.5%, P=.1). Intracoronary ultrasound performed after 4 years in a subgroup of 27 patients (simvastatin, 10; control, 17) showed less intimal thickening in patients with LDL-cholesterol levels of <110 mg/dL (170+/-84 versus 370+/-171 microm, P=.04) and a lower intimal index (13.8+/-7.1% versus 27.9+/-12.1%,P=.04). CONCLUSIONS: In comparison with dietary measures alone, the combination of a low-cholesterol diet and simvastatin after heart transplantation led to a significant reduction in cholesterol levels, a significantly higher long-term survival rate, and a lower incidence of GVD.

Adult↗
PubMed1997

Pharmacy-managed program for home treatment of deep vein thrombosis with enoxaparin.

A program for home treatment of uncomplicated acute proximal deep vein thrombosis (DVT) with enoxaparin is described. In fall 1995 an HMO in Southern California began developing a pharmacy-managed program in which selected patients with acute proximal DVT receive home treatment with enoxaparin. Advantages of the program included expected cost avoidance. The safety and efficacy of such therapy were verified, and quality control measures were established. Patients are referred to the program by the physicians making the diagnosis of proximal DVT. Upon referral, patients are placed in a holding area. A pharmacist orders laboratory tests and then prescribes warfarin and enoxaparin doses. Patients are given their first doses, taught to safely self-administer enoxaparin, and sent home. Follow-up care, monitoring, and blood sampling are provided through a home health agency. A pharmacist monitors the International Normalized Ratio (INR) and telephones the patient daily to specify the day's warfarin dose. Patients receive concurrent enoxaparin and warfarin therapy for at least five days until the INR is > 2; enoxaparin is then discontinued and patients are transferred to an outpatient anticoagulation service for continued monitoring. From April 1, 1996, to March 27, 1997, 55 patients were treated under the program; all eligible patients were enrolled. A total of 294 hospital days were avoided. There were no complications or hospital admissions due to bleeding. A comprehensive program for home treatment of uncomplicated acute proximal DVT with enoxaparin was implemented at an HMO.

Acute Disease↗
PubMed1997

Ten-year follow-up results from the Goettingen Risk, Incidence and Prevalence Study (GRIPS). I. Risk factors for myocardial infarction in a cohort of 5790 men.

Besides the accepted major risk factors for myocardial infarction (MI), cholesterol, hypertension and smoking, several other variables such as lipoproteins, apolipoproteins, fibrinogen and family history of MI, have been considered, but their usefulness as predictors of MI is controversially discussed. The Göttingen Risk Incidence and Prevalence Study (GRIPS) aimed to evaluate the independent impact of the latter in comparison to the established risk factors. GRIPS is a prospective cohort study, which included 5790 men, aged 40-59.9 years, without cardiovascular disease at baseline. Multivariate logistic regression models for the estimation of the MI risk based on the 10-year follow-up data from 97.4% of the study participants established LDL cholesterol as the strongest predictor of MI. It was followed by family history of MI, Lp(a), age, smoking, systolic blood pressure, HDL cholesterol (inversely related) and plasma glucose (P < 0.001). Apolipoprotein B as well as the ratios total/HDL cholesterol, LDL/HDL cholesterol and Apo B/AI were less effective predictors than LDL cholesterol and did not contribute independently to the estimation of MI risk. Similarly apoprotein AI was a weaker predictor of MI risk then HDL cholesterol. GRIPS is the first prospective cohort study which clearly justifies the key role of LDL cholesterol in preventive strategies. However, the data also give strong support for the additional consideration of other risk factors for a valid estimation of the MI risk for an individual subject.

Blood Glucose↗
PubMed1997

The Er:YAG laser in ear surgery: first clinical results.

BACKGROUND AND OBJECTIVE: The goal of this study was to gain experiences about the possibilities and limits of the Er:YAG laser for ear operations. STUDY DESIGN/PATIENTS AND METHODS: Eighty-three ear operations were performed with the aid of an Er:YAG laser: 32 stapedotomies, 15 tympanoplasties type III, 10 tympanoplasties type I, 18 ear operations in cholesteatoma, and 8 removals of hyperostosis in the outer ear canal. RESULTS: The Er:YAG laser facilitated stapedotomies and removal of hyperostosis from the outer ear canal. In cases of beginning cholesteatoma, the Er:YAG laser allowed matrix removal of the ear ossicles left in situ. Furthermore, in tympanoplasty it was possible to achieve an osteosynthesis of the auditory ossicles, which was done for the first time during this study. No hearing loss attributable to laser dose was found during postoperative hearing tests. CONCLUSION: The Er:YAG laser seems to become a useful tool in middle ear surgery.

Adolescent↗
PubMed1997

Is free prostate-specific antigen helpful in the differential diagnosis of benign hyperplasia and cancer of the prostate?

PURPOSE: We studied the clinical relevance of the determination of free prostate-specific antigen (f-PSA) in addition to total PSA (t-PSA). METHODS: Both t-PSA and f-PSA values of frozen sera obtained pretherapeutically from 80 patients with prostate carcinoma (PC) and 171 patients with benign hyperplasia of the prostate (BPH) were analyzed by means of the Tandem-E PSA and Tandem-R f-PSA immunoassays (Hybritech, San Diego, Calif.). RESULTS: At 95% specificity, a cutoff value of 15.7 micrograms/l was obtained for t-PSA [9 patients with BPH (5%) were above this value]. For this cutoff value, we calculated a sensitivity of 50% (40 patients with PC were above this value). Using the same criteria for the ratio (Q) f-PSA:t-PSA a cutoff of 0.086 was found again at a specificity of 95%. In a second step, only patients with t-PSA values below the cutoff level of 15.7 micrograms/l were considered. Out of these patients, 6 of 156 with BPH (missing values = 6) and 11 of 40 with PC were below the above-mentioned ratio (Q = 0.086). Therefore, sensitivity was 28% for this subgroup. Considering both steps (t-PSA and Q) 51 patients with PC were detected correctly and 15 patients with BPH would have undergone biopsy unnecessarily (positive biopsy rate: 77%). CONCLUSIONS: High t-PSA levels are very good indicators for the presence of PC. There is still concern for improving the differentiation between BPH and PC, when an intermediate or low value (< or = 95% specificity) is observed. The determination of Q is only useful in this range and is helpful for the clinician's decision whether to apply or avoid biopsy.

Biomarkers, Tumor↗
PubMed1997

Increased oxidation of LDL in patients with coronary artery disease is independent from dietary vitamins E and C.

There is increasing experimental evidence that oxidation of LDL plays a major role in the pathogenesis of coronary artery disease (CAD). However, results from clinical studies on LDL oxidation and CAD are not consistent. In most studies only single plasma factors of LDL oxidation have been determined. We studied 207 patients who underwent coronary angiography. They were divided into subjects with CAD (n = 137) and those without CAD (n = 70). We determined the susceptibility of LDL to in vitro oxidation (lag phase), potential prooxidative and antioxidative plasma factors (plasma vitamin E, LDL vitamin E, ascorbate, iron, copper, ferritin, and ceruloplasmin), and markers of in vivo LDL oxidation (autoantibodies to malondialdehyde-modified LDL, oxidized LDL, and thiobarbituric acid-reactive substances), plasma lipids and lipoproteins, smoking habits, and other coronary risk factors in both groups. The lag phase was significantly shorter in patients with CAD than in patients without CAD (101 +/- 38.6 versus 119 +/- 40.6 minutes, P < .01). There was no correlation between the lag phase and the other oxidation parameters or the coronary risk factors. In multivariate regression analyses the lag phase remained significant in all tested models. Our data suggest that a short lag phase of LDL oxidation might be an independent risk factor of CAD.

Aged↗
PubMed1997

Multicentre evaluation of the urine analyser Miditron Junior.

A multicentre evaluation of the urine analyser Miditron Junior was performed at four laboratories. The Miditron Junior analyser provides semi-quantitative results for erythrocytes, bilirubin, urobilinogen, ketone bodies, glucose, protein, nitrite, leukocytes, pH and relative density. Accuracy of the Miditron Junior analyser was evaluated by comparison to quantitative analytical chemistry methods (glucose, total protein), physical methods (pH, relative density), and microscopic methods (erythrocytes, leukocytes). Agreement was defined as identical or neighbouring concentration block. The level of agreement found with chemical, physical or microscopic methods for the six analytes tested varied from 79 to 99%. The within-run precision was determined as repeatability by using 31 native urines. The results of repeated measurements (n = 10) fell in the same concentration block, or in case of borderline concentration were spaced between two adjacent colour blocks. Day-to-day precision covering a minimum of 20 days using commercially available control solutions yielded results within +/- one colour block from the mean.

Colorimetry↗
PubMed1996

Differential effects of glucocorticoids on human auditory perception.

It is assumed that glucocorticoids and mineralocorticoids, the hormones produced by the adrenal cortex, act as modulators of central nervous functions in addition to their well-known role in endocrine stress responses. More specifically, it has been suggested that adrenal corticoids cause changes in sensory thresholds. In two double-blind crossover studies we evaluated auditory perception in healthy volunteers after treatment with hydrocortisone, dexamethasone, and the respective placebos. Stapedial reflexes, pure tone and speech audiograms, and brainstem electric response audiometry served as the dependent variables. As circadian changes in the density and occupancy of the brain corticosteroid receptors have been postulated, we performed Study I in the morning and Study II in the evening. Treatment effects clearly varied with time of day. A differential effect of the two corticoids occurred on contralateral stapedial reflexes. These results parallel results obtained with gustatory stimuli, and suggest that glucocorticoids modulate sensory perception across modalities.

Adult↗
PubMed1996

Anaerofilum pentosovorans gen. nov., sp. nov., and Anaerofilum agile sp. nov., two new, strictly anaerobic, mesophilic, acidogenic bacteria from anaerobic bioreactors.

Strictly anaerobic, gram-positive, nonsporing, thin rod-shaped organisms whose cells were 0.2 to 0.6 by 3 to 6 microns were isolated from a Hoechst Biohochreaktor (strain FaeT [T = type strain]) and from the biofilm population of a fixed-film reactor treating sour whey (strain FT). Strain FT was vigorously motile during early logarithmic growth by means of peritrichously inserted flagella, while strain FaeT was seldom motile and usually possessed no flagella. During the stationary growth phase both strains formed spheroplasts. The temperature optimum was close to 37 degrees C (temperature range for growth, > or = 17 to < 45 degrees C) and the pH optimum was 7.0 to 7.4 (pH range, 6.5 to 8.0) for both strains. The two organisms grew chemoorganotrophically on a number of mono- and disaccharides, including glucose and xylose; yeast extract was required for growth. The principal fermentation products from glucose included lactate, acetate, ethanol, formate, and CO2. Hydrogen was not generated. The G + C contents of the DNAs of strains FaeT and FT were 55 and 54.5 mol%, respectively. The cell wall architecture was typical of gram-positive bacteria; the cells had an extraordinarily thin type A3 alpha' peptidoglycan layer containing muramic acid. Analysis of 16S ribosomal DNA sequences of the two new isolates demonstrated that they represent members of a new genus of bacteria in Clostridium cluster IV of the domain Bacteria and that the misclassified organism Fusobacterium prausnitzii and Clostridium leptum are among their closest relatives. The names Anaerofilum pentosovorans gen. nov., sp. nov. (type strain, strain Fae [= DSM 7168]) and Anaerofilum agile sp. nov. (type strain, strain F [= DSM 4272]) are proposed.

Anaerobiosis↗
PubMed1996

Multicentre evaluation of an immunological rapid test for the detection of troponin T in whole blood samples.

In a multicentre study we assessed the analytical and diagnostic performance of a rapid test (TROPT rapid test, Boehringer Mannheim; in the USA: CARDIACT) for cardiac troponin T compared to quantitative troponin T ELISA and creatine kinase-MB mass determinations. The rapid test requires 150 microliters of heparinized or EDTA whole blood; serum is not suitable. Interference testing with biotin, haemoglobin and 27 standard drugs yielded no significant influence in the physiological range. Skeletal muscle troponin T concentrations > or = 40 micrograms/l gave positive results with the rapid test. We used the rapid test for 369 samples from 203 patients with suspected acute coronary syndromes and compared the results to troponin T ELISA and creatine kinase-MB mass. 90 patients (44%) were primarily classified as having myocardial infarction by the WHO criteria. Twenty-two (20%) of the 113 non-myocardial infarction patients were unstable angina pectoris cases showing increased troponin T ELISA but not increased creatine kinase-MB mass values. Consequently, these were classified as minor myocardial damage cases. The rapid test was positive in 99% of all samples with a troponin T ELISA value > or = 0.30 micrograms/l and negative in 95 to 96% of all samples below this value. Diagnostic sensitivities for the detection of acute myocardial infarction within the first 12 hours after onset of pain were the same, 90%, for the rapid test, troponin T ELISA and creatine kinase-MB mass. After 48 hours, diagnostic sensitivity of creatine kinase-MB mass sharply decreased whereas that of the troponin T assays remained close to 100% beyond 72 hours after onset of symptoms. Diagnostic specificities for acute myocardial infarction (WHO) of all markers remained between 80 and 100% over this time. The diagnostic sensitivity of the rapid test for the detection of high risk unstable angina pectoris patients with minor myocardial damage was nearly the same as for troponin T ELISA. A major advantage of the rapid test is the ease of use and 20 minute turn around time. This facilitates the detection of increased troponin T at alternate sites.

Biomarkers↗