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Biomedical subjects

B Lemke

Publications and source records attributed to B Lemke.

At least 19 recordsLinked to original sources
PubMed2000

[Health promotion and cardiovascular risk factors. The level of knowledge among 510 inpatients of an acute coronary care unit].

PATIENTS AND METHODS: A total of 510 patients hospitalized on a cardiologic ward were questioned on cardiovascular disease risk factors using a questionnaire. The knowledge on these risk factors was assessed with a score system. RESULTS: Knowledge of patients on cardiovascular disease risk factors was generally low: One out of 5 did not know about the consequences of obesity, high blood cholesterol or smoking on the coronary vessels. Over 30% did not name hypertension. Only 1 out of 3 patients mentioned diabetes mellitus as a risk factor. There was no change in the knowledge during the hospital stay despite a standardized and intensive information program. The results of the second survey on the day of discharge were equal to the results of the admission day. Hospital stays in the past had no influence on the knowledge. Patients with a diagnosed coronary heart disease had the same results in the survey as patients with other diseases. The presence of risk factors had hardly any influence on the knowledge of these patients. CONCLUSION: The result of this study emphasizes the need for better health information for patients. The repetitive information on health related issues during inpatient treatment does not seem to have a positive effect on patients' knowledge. Therefore other ways of health education have to be introduced and evaluated in acute care.

Adult↗
PubMed2000

Characterization of muscle filamin isoforms suggests a possible role of gamma-filamin/ABP-L in sarcomeric Z-disc formation.

Filamin, also called actin binding protein-280, is a dimeric protein that cross-links actin filaments in the cortical cytoplasm. In addition to this ubiquitously expressed isoform (FLN1), a second isoform (ABP-L/gamma-filamin) was recently identified that is highly expressed in mammalian striated muscles. A monoclonal antibody was developed, that enabled us to identify filamin as a Z-disc protein in mammalian striated muscles by immunocytochemistry and immunoelectron microscopy. In addition, filamin was identified as a component of intercalated discs in mammalian cardiac muscle and of myotendinous junctions in skeletal muscle. Northern and Western blots showed that both, ABP-L/gamma-filamin mRNA and protein, are absent from proliferating cultured human skeletal muscle cells. This muscle specific filamin isoform is, however, up-regulated immediately after the induction of differentiation. In cultured myotubes, ABP-L/gamma-filamin localises in Z-discs already at the first stages of Z-disc formation, suggesting that ABP-L/gamma-filamin might play a role in Z-disc assembly.

3T3 Cells↗
PubMed1999

Comparison of the efficacy and safety of aspirin alone with coumadin plus aspirin after provisional coronary stenting: final and follow-up results of a randomized study.

BACKGROUND: The antithrombotic benefit of the conventional treatment with coumadin after coronary stenting is limited by bleeding complications. However, the superiority of an antiplatelet therapy with aspirin alone compared with coumadin plus aspirin has not been proven by randomized studies. The efficacy and safety of treatment with aspirin alone in comparison to coumadin plus aspirin were evaluated in this randomized study. METHODS: Out of 164 patients aged 59.7 +/- 9.2 years, 79 patients were randomly assigned to receive 100 mg aspirin daily (group A) and 85 patients randomly assigned to coumadin plus aspirin (group CA) after provisional coronary stenting with a high-pressure technique. The primary end point was defined as the absence of death, subacute closure of the target vessel, myocardial infarction, urgent coronary bypass surgery, repeated coronary angioplasty, and peripheral vascular complications requiring transfusion or surgery. High-pressure inflation technique was used, but ultrasound guidance was not. RESULTS: During hospitalization (median 8 days), 135 patients (82. 3%) were free of events (A, 84.8%; CA, 80.8%; P =.42). Eleven (6.7%) subacute closures occurred (A, 10.1%; CA, 3.5%; P =.09); 2 of them were lethal in the aspirin group. Emergency bypass surgery was performed in 1 patient in each group. Peripheral vascular complications were observed in 13 patients (7.9%) (A, 1.3%; CA, 14. 1%; P <.01). At 3-month follow-up, 15 (9.1%) elective revascularization procedures (A, 7.6%; CA, 10.6%; P =.51) were performed. CONCLUSION: Aspirin alone at the low dose of 100 mg administered or the combination of coumadin and aspirin after high-pressure coronary stenting does not prevent adverse clinical events when ultrasound guidance is not used.

Angioplasty, Balloon, Coronary↗
PubMed1999

Restoration of cardio-circulatory regulation by rate-adaptive pacemaker systems: the bioengineering view of a clinical problem.

In the past, the development of rate-adaptive (sensor-controlled) pacemaker systems seems to have been determined primarily by the availability, compatibility and other properties of the technical sensor. This paper, however, focuses on the system-physiological aspect in an attempt to answer the question to what extent physiological cardiovascular control is restored by the pacemaker system. This is a question which should be asked before attempting to design a sensor-controlled system and especially before designing multisensor systems with infinite combinations. Four categories are defined: direct bridging ("shunting"), open loop systems, closed systems using cardiorespiratory or metabolic coupling and those using cardiac signals. Further subdivisions are shown. From the bioengineering as well as from the physiological viewpoint a system should preferably not combine sensors from one and the same of these categories. At present direct bridging is available only for the atrioventricular (AV)-block, so that for sick-sinus-syndrome (SSS) patients feedback control via cardiac signals ("inotropic" pacemaker) comes nearest the goal without, however, ideally bridging the gap. Open-loop systems should no longer be developed as single-sensor systems. A well developed activity sensor, however, which quickly pinpoints the most prominent stressor of cardiovascular control is best suited to complement another sensory system achieving closed-loop control. New and promising concepts orientated toward direct bridging are the analysis of monophasic action potentials and the "dromotropic" concept, both of which seek direct correlation with the "chronotropic" information not available in SSS patients.

Adaptation, Physiological↗
PubMed1999

Influence of the pacing rate on the atrioventricular conduction time during aerobic and anaerobic exercise: basic concepts for a dromotropically controlled rate responsive pacemaker.

The dromotropic pacemaker concept needs a rate responsive algorithm in which the pacing rate is controlled by the atrioventricular conduction time (AVCT). To develop basic concepts for such a rate responsive algorithm, the influence of the pacing rate on the AVCT was investigated. Seven patients (62 +/- 7.8 years) with sick sinus syndrome and intact atrioventricular conduction underwent two cardiopulmonary exercise tests (CPX) on a treadmill. According to the determination of the anaerobic threshold (AT) and the patients maximum capacity in the first incremental CPX the work rate for two exercise levels below and above the AT were chosen for the second constant workload CPX. The calculation of the optimal pacing rate (HRopt) was based on the oxygen uptake (VO2) during exercise after reaching steady-state conditions. According to the increase of the VO2 from 14.8 +/- 2.3 mL/min per kilogram during aerobic work (38.3 +/- 16.0 W) to 19.4 +/- 4.7 mL/min per kilogram during anaerobic work (80.6 +/- 32.3 W), the HRopt was calculated to be 98.6 +/- 6.9 beats/min and 116.4 +/- 4.7 beats/min. Starting from HRopt, the pacing rate was increased (overpacing) and decreased (underpacing) by about 5 beats/min every minute. At optimal pacing rate the AVCT decreased significantly from 233.0 +/- 30.5 ms during aerobic work and to 226.4 +/- 27.3 ms during anaerobic work (P < 0.05). Whereas overpacing induced a significant prolongation of the AVCT during aerobic work (4.17 +/- 1.78 ms per 10 beats/min) and anaerobic work (3.84 +/- 1.60 ms per 10 beats/min), underpacing yielded a significant shortening of the AVCT by about 4.49 +/- 2.64 ms per 10 beats/min during aerobic work and 4.75 +/- 1.87 ms per 10 beats/min during anaerobic work (P < 0.01). The slopes of the regression lines of the relationship between AVCT and pacing rate were not significantly. different. Based on the reciprocal relationship of heart rate (HR) and AVCT, basic concepts may be established for a dromotropic rate responsive algorithm.

Aged↗
PubMed1999

Relationship between atrioventricular delay and oxygen consumption in patients with sick sinus syndrome: relevance to rate responsive pacing.

To develop a dromotropic-controlled rate adaptive algorithm for patients with sick sinus syndrome (SSS) and intact AV conduction, 14 pace-maker patients with SSS underwent cardiopulmonary exercise testing (CPX). During exercise, the pace-maker was programmed in an AAT mode without rate adaptation, whereby 3 patients developed supraventricular arrhythmia and 11 patients kept sinus rhythm. Chronotropic incompetence (CI) at heart rate (HR) < 95 beats/min at the anaerobic threshold (AT) was found in five patients. In patients with chronotropic competence (CC), the HR increase was significantly greater than in CI patients (rest: 73.2 +/- 12.6 vs. 64.2 +/- 4.0 beats/min;AT:101.2 +/- 6.2 vs. 82.0 +/- 5.1 beats/min;peak: 135.2 +/- 10.7 vs. 103.2 +/- 10.9 beats/min). There was no significant difference in the AVD between CC and CI patients (rest: 167.7 +/- 38.6 vs. 170.8 +/- 22.5 ms, AT: 156.2 +/- 30.7 vs. 163.6 +/- 21.6 ms, peak: 144.7 +/- 29.0 vs. 152.4 +/- 15.0 ms). The correlation coefficient between HR increase and VO2 was +1.0 and between AVD decrease and VO2 - 1.0 in both groups. An increase in pacing rate from 75 beats/min to 120 beats/min without exercise (overpacing) led to a prolongation of the AV interval of about 30.6 +/- 14.2 ms. Based on this closed loop control with negative feedback, a dromotropic rate adaptive algorithm for patients with SSS and intact AV conduction could be developed.

Aged↗
PubMed1999

Excess retinol intake may explain the high incidence of osteoporosis in northern Europe.

An epidemiologic study of postmenopausal women in Sweden revealed that a chronic excess of retinol intake (> 1.5 mg/day) decreased bone mineral density and increased hip fracture risk. These data provide one explanation for the higher incidence of osteoporosis in Sweden and Norway compared with other European countries. Retinol in fortified milk could explain also the association of high calcium intake and hip fracture incidence in northern Europe because milk is an important source of both nutrients.

Bone Density↗
PubMed1998

[Submaximal spiroergometric stress study in patients with mixed dust pneumoconiosis].

Disabilities of patients with coal-workers' pneumoconiosis (CWP) are currently estimated by changes in lung function at rest and the degree of dust equivalents in chest x-ray (ILO-classification 1980). Functional disturbances during exercise are not taken into consideration on a regular basis. We assumed that standardised sub-maximal exercise tests might be useful even in disabled patients to give additional information on functional disabilities of patients with CWP. The impact of low-grade anthracosilicosis on ventilation and gas exchange during exercise was assessed in 20 patients (all male, age 64.55 +/- 3.78 years) and 24 healthy volunteers (all male, age 58.13 +/- 4.68 years, never dust exposed). Data were also analysed according to ILO classification subgroups (group 1: ILO-classification 1/0 to 1/2, n = 11; group 2: ILO-classification 2/1 to 2/2, n = 9). Heart rate (HR), minute ventilation (VE), ventilatory equivalent for O2 (VE/VO2), ventilatory equivalent for CO2 (VE/VCO2), O2 uptake (VO2)CO2 output (VCO2), end-tidal oxygen partial pressure (PetO2), end-tidal carbon dioxide partial pressure (petCO2) and estimated dead space to tidal volume ratio (VD/VT) were determined breath-by-breath during a 50 watts constant work load protocol on an exercise bicycle. The VE/VO2 (patients: 32.9 +/- 4.2; controls: 25.7 +/- 2.9; p < 0.001), the VE/CO2 (patients: 39.4 +/- 4.6; controls; 31.0 +/- 3.9), the VE (patients: 30.1 +/- 5.6, controls: 23.5 +/- 3.0; p < 0.001) and the PetO2 (patients 115.6 +/- 4.8; controls: 99.1 +/- 27.4; p < 0.05) at an exercise of 50 watts were significantly higher in the patients' group, the PetCO2 (patients: 38.4 +/- 4.5; controls: 44.0 +/- 4.1) were significantly lower in the patients' group. The comparison of patients subgroups did not reveal any significant differences between group 1 and group 2. A higher VE/VO2 during 50 watts of exercise is attributable to an increased ventilation/perfusion mismatch. There was no correlation between the radiological grade of the CWP (ILO classification) and the ventilation and gas exchange during exercise. We conclude that a sub-maximal spiroergometry with a 50 watts constant work load might serve as a sensitive and easy to apply procedure add information about the functional impairment in CWP. The exercise test should be included in the evaluation for disability benefits.

Adult↗
PubMed1997

[Intravascular ultrasound findings in calcifying arteriosclerosis: in vitro validation using "soft" roentgen images].

AIM: The aim of this study was to validate the detection of calcified arteriosclerotic plaques with intravascular ultrasound (IVUS). METHOD: 181 arteries were examined by 20/30 MHz IVUS. The ultrasound cross-sections were compared to the corresponding radiologic (30 kV) and histologic cross-sections. RESULTS: Calcified lesions were imaged as bright echos with shadowing. In 13 cases of 161 calcified lesions were too small to detect by IVUS. In 5 ultrasonic sections the diagnosis "calcified lesion" could not be verified neither by radiology nor by histology. The sensitivity was 91.6%, the specificity was 94.7% and the accuracy was 93.0%. CONCLUSIONS: Because of the acoustic properties of calcium, calcified lesions can be detected accurately by IVUS. IVUS can generate new insights into the effect of plaque composition on the response to catheter therapies.

Aged↗
PubMed1997

High Pressure Coronary Stenting: Efficacy and Safety of Aspirin Versus Coumadin Plus Aspirin Ñ Preliminary Results of a Randomized Study.

The efficacy and safety of treatment after coronary stenting was examined with aspirin alone, 100 mg daily, as compared to coumadin plus aspirin. Data from the first 101 patients, 73 men and 28 women, aged 59.2 +/- 9.3 years, of a prospective randomized study are presented in this preliminary report. Forty-eight patients suffered from one-vessel disease, 32 had two- and 21 three-vessel disease. Indications for stenting were stable angina in 65 patients, unstable angina in 16, threatening myocardial infarction in 4 and restenosis in 16 patients. The stents were implanted by high pressure balloon inflation (14.5 +/- 2.2 atm), 55 of them were Palmaz-Schatz, 31 Micro, 10 Gianturco-Roubin, 2 Wiktor and 3 combined stents. Intravascular ultrasonographic guidance was not performed. The primary end point was defined as the absence of the following events: death, subacute coronary artery closure, acute myocardial infarction, emergency coronary bypass surgery, repeated PTCA, major bleeding or arterio-venous aneurysms needing transfusion or surgery. Eighty out of 101 patients (79.2%), 41 out of 47 (87.2%) in the aspirin group and 39 out of 54 (72.2%) in the coumadin plus aspirin group (p = 0.06) were free of events during hospitalization (9.5 +/- 5.7 days, median: 8 days). Forty-five out of 47 patients (95.7%) in the aspirin and 51 out of 54 (94.4%) in the coumadin plus aspirin group (p = 0.8) were without subacute closure. One death occurred in the aspirin group due to stent abscess two weeks after an angiographically successful stent recanalization. All 7 arterio-venous aneurysms with surgical interventions occurred in the coumadin group (p = 0.01). No emergency bypass surgery had to be performed. If these preliminary results will be confirmed by the final analysis, the combination of coumadin with aspirin does not show more efficacy or safety as compared with aspirin alone in the treatment after high-pressure coronary stenting during the hospital stay.

Journal Article↗
PubMed1995

[Effect of the degree of revascularization on left ventricular function after aortocoronary bypass operation].

BACKGROUND: The extent of myocardial revascularisation by aortocoronary bypass surgery can only be quantitatively evaluated by using precise criteria. In this retrospective study the effect of coronary surgery on left ventricular function was analyzed. PATIENTS AND METHODS: In 161 patients, 148 male and 13 female, aged 52.5 +/- 7.0 years (33 to 69 years) with 1 (7%), 2 (38%) or 3 vessel disease (55%) the left ventricular function was analyzed by Swan-Ganz catheterization at rest and on exercise, five months before and after coronary bypass operation. Coronary artery and bypass lesions were quantified according to a new detailed score including diseased main or side branches, segment 1 to 3, type of irrigation and area reduction of the artery cross-section. Pulmonary capillary wedge pressure and cardiac index were measured and related to the grade of revascularisation (RG) and pre-operative ejection fraction (EF), classified in the groups RG1 < 50%, n = 54; RG2 50 to 74%, n = 52; RG3 > or = 75%, n = 55, EF1 < 60%, n = 30 and EF2 > or = 60%, n = 129. RESULTS: The change in pulmonary capillary wedge pressure on exercise was in RG1, RG2 and RG3 -26.2%, -29.0% and -40.9%, respectively (p < 0.001). It was significantly higher in RG2 and RG3 than in RG1. The increase in cardiac index on exercise was significant only in groups RG2, RG3 and EF2 (p < 0.005). CONCLUSION: Adequate improvement of left ventricular function can be expected when a grade of revascularisation of 50% and more is achieved.

Adult↗
PubMed1993

Two-dimensional echocardiographic assessment of right cardiac pressure overload in patients with chronic obstructive airway disease.

Two-dimensional echocardiography was used to estimate right cardiac pressure overload in patients with chronic obstructive airway disease. Area measurements of the four heart chambers were carried out from the apical four-chamber view. Additionally, the respiratory behaviour of the inferior vena cava was examined from the subcostal view. A good apical imaging of the four-chamber view for area measurement was obtained in 44 out of 48 patients with chronic obstructive airway disease. The respiratory behaviour of the inferior vena cava was investigated from the subcostal view in 38 patients. Within 8 days after echocardiography, right cardiac catheterization was carried out in order to measure pulmonary artery and right atrial mean pressures and to determine pulmonary vascular resistance. A good correlation was found between pulmonary artery mean pressure and the following echocardiographic parameters: area index (area/body surface) of the two right heart cavities (r = 0.83), right-to-left ventricular area ratio (r = 0.82) and right-to-left cardiac area ratio (ratio between the added areas of both right heart cavities on the one side and the added areas of both left heart cavities on the other; r = 0.82). Correlation between these parameters and pulmonary vascular resistance (r = 0.71, 0.66 and 0.71, respectively) and between the right atrial mean pressure and the right atrial area index was less close (r = 0.64). On the other hand, the respiratory behaviour of the inferior vena cava proved to be highly specific but not very sensitive in predicting a pathological right atrial pressure.(ABSTRACT TRUNCATED AT 250 WORDS)

Atrial Function, Right↗
PubMed1992

[The importance of 201-thallium myocardial scintigraphy in the hypertensive patient].

Thallium-201 exercise myocardial scintigraphy was performed in 57 patients (37 males, 20 females; mean age 55.4 [43-78] years) with angina and systemic hypertension after exclusion by coronary angiography of any coronary macroangiopathy. The exercise ECG of 32 patients could not be used in the diagnosis of ischaemia because of the presence of left ventricular hypertrophy with abnormal repolarization or left bundle branch block. Abnormal haemodynamics were demonstrated at cardiac catheterization in 23 patients (Swan-Ganz). Only 10 of the studied hypertensives with normal coronary angiograms had a myocardial scintigram within normal limits, while 12 had extensive ischaemic zones in the left ventricle. All patients with left bundle branch block had evidence of exercise-dependent apical "ischaemia". Thallium-201 myocardial scintigraphy should not be used as a screening method in hypertensives with angina, because the high proportion of "false-positive" findings, in the sense of a macroangiopathy, will nevertheless require early invasive diagnosis.

Adult↗
PubMed1992

Aerobic capacity in rate modulated pacing.

Whether heart rate or AV synchrony is the most important factor for an increase in aerobic capacity was evaluated in a comparative study between sinus bradycardia, VVIR, DDD, and DDDR stimulation. Sixteen patients (mean age 67 years) with chronotropic incompetence and implanted DDDR pacemaker (Telectronics META 1250) were randomly studied by cardiopulmonary exercise testing. All patients were exercised to their anaerobic threshold (AT) with the following heart rates: DDD 84 +/- 3, VVIR 110 +/- 5, and DDDR 116 +/- 6 beats/min. Mean oxygen uptake (VO2, mL/kg per min) at AT was 7.4 +/- 0.3 in DDD and VVIR modes. A 12% increase was measured in DDDR mode (8.3 +/- 0.4). Compared to VVIR work capacity in the DDDR mode was improved by 17% (41 vs 48 W/min). In patients with isolated sinus node disease (n = 9) the increase of VO2 and work capacity at AT during DDDR mode was more pronounced (16% and 20%, respectively, compared to VVIR). In patients with intermittent second or third degree AV block (n = 7) the differences between the pacing modes were not significant. This might partly be due to a lesser degree of chronotropic incompetence in this subgroup. In conclusion only the conjunction of heart rate increase and preservation of AV synchrony provides a significant improvement in aerobic capacity during exercise.

Aged↗
PubMed1991

[Intolerance reactions to ionic and nonionic contrast media in cardiac diagnosis. A randomized double-blind study].

Reactions to an ionic and a nonionic contrast medium were compared in a randomized double-blind trial involving 1153 patients (897 men, 256 women; mean age 56 [18-84] years) who underwent left-heart catheterization with coronary angiography. 584 patients (group 1) received the ionic contrast medium meglumine diatrizoate (Urografin 76%), while 569 (group 2) received the nonionic iopromide (Ultravist -370). Reactions of skin and mucosae, heart and circulation, lungs and respiratory tract, as well as of the central nervous system were noted. There was no significant difference between the two groups with respect to age, weight, height, allergic predisposition, left-ventricular ejection fraction, or serum electrolyte concentrations. Mild reactions, not requiring any treatment, occurred in 108 of the 1153 patients (9.4%), 85 (14.6%) in group 1 and 23 (4%) in group 2 (P less than 0.001). Severe reaction requiring treatment occurred in eight patients of group 1 (1.4%) and 14 of group 2 (2.5%)--difference not significant. Ventricular fibrillation was more frequent among group 2 patients (four compared with one in group 1), while two of three asystoles requiring treatment occurred in group 1 patients. The results show that, while mild reactions not requiring treatment were clearly less frequent after nonionic contrast medium injection, the risk of severe reactions was not reduced by their use.

Adolescent↗