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Biomedical subjects

R Lemke

Publications and source records attributed to R Lemke.

At least 55 records · Page 3Linked to original sources
PubMed1984

[Fatal E 605 poisoning following intravenous administration].

Lethal toxification by organophosphate insecticides like E-605 are mostly the result of oral ingestion for the purpose of suicide or accidental ingestion by inhalation. An unusual case is reported of E-605 poisoning by injection into the basilic vein. Referring to this case, our findings on distribution of the noxa are presented and discussed.

Adult↗
PubMed1982

[R-wave amplitude during left ventricular volume changes in healthy hearts].

The relationship between R-wave amplitude and left ventricular volume was studied in four tests, each including six normal adults. The means of 10 heart cycles of the R-wave amplitude in surface ECG lead V5 (RV5) and the echocardiographically determined left ventricular enddiastolic dimension (LVEDD) were compared before and during different interventions. After inhalation of 0.3 ml isoamylnitrit, LVEDD was reduced to 7.7%, RV5 to 15.0% below control. During a maneuver of Valsalva, LVEDD decreased to 8.6%, RV5 to 12.9% below control. In both tests heart rates increased markedly. After oral application of propranolol (0.7 to 1.0 mg/kg) LVEDD did not change, whereas RV5 decreased to 8.2% below control. During rapid intravenous infusion of 1 l NaCl 0.9% in 10 to 15 minutes, LVEDD increased to 15.7% above control. R-wave amplitude remained constant. Thus the results of these last two tests let us doubt whether the Brody-effect can be translated without limitation on the in-vivo situation in man.

Adult↗
PubMed1981

[In-vitro studies for the echocardiographic evaluation of abnormal movement of the Starr-Edwards disc prosthesis, in mitral position due to disruption of sutures (author's transl)].

The movement of a Starr-Edwards disc prosthesis was studied in vitro. The best registration of the valve was achieved when the disc was positioned at a 90 degree angle to the echo-beam. At an angle of 45 greater than, there was still a satisfactory registration. Due to an increase of echoes, an exact measurement of the valve excursion proved to be difficult. In the presence of disrupted sutures, which caused tilting of the entire valve apparatus, the amplitude of this movement was superimposed on the amplitude of the disc excursion. The disc showed a so-called "hump" independent from the position of the disrupted suture. A movement of the entire valve apparatus towards or opposite from the transducer caused a similar movement of the disc as the disruption of sutures. These findings support the conception that although a relatively easy echocardiographic registration of the Starr-Edwards disc prosthesis can be obtained, slight changes caused by disrupted sutures cannot be successfully differentiated from movements of the entire valve apparatus with the M-mode echocardiography.

Echocardiography↗
PubMed1981

[ST-segment depression and R-amplitude changes during bicycle stress test in patients with coronary artery disease (author's transl)].

56 patients were examined with bicycle stress tests. Sensitivity and specificity of ST-segment depression were compared with R-wave amplitude changes. All patients had a coronary angiography because of suspected coronary artery disease (CAD). The specificity of ST-segment depression was 71%, for R-wave amplitude changes 50%. The sensitivity for ST-segment depression was 76% and for R-wave amplitude changes 50%. In addition in 7 patients with angiographically demonstrated CAD repeated stress tests were done. The ST-segment changes were nearly constant in all examinations, whereas the R-wave amplitude in V5 in 5 out of 7 patients changed considerably between decrease and increase. Considering these intraindividual changes, it seems doubtful whether the evaluation of the R-wave amplitude proves to be an improvement of the non-invasive diagnostic procedures of CAD.

Coronary Disease↗
PubMed1980

[In vitro studies for the echocardiographic evaluation of pathologic movement of the björk-shiley valve in mitral position in the presence of loose sutures (author's transl)].

A Björk-Shiley disc valve was sutured into a plastic syringe with 4 threads. With the piston of the syringe it was possible to close and open the disc in a waterbath. The syringe was rotated along the long axis stepwise, in a 45 degrees-fashion up to 360 degrees. In each position an echocardiographic registration was performed. The best registration was achieved, if the axis around which the disc is pivoting was positioned at a 90G-angle to the echo-beam, and if there was a maximum excursion of the disc towards the transducer. The threads were cutt off, one after the other, so that an additional movement of the valve ring could be registered. Depending on the position of the loose thread, the movement of the ring added to, or substracted itself from the disc movement. A "hump", which is considered typical for paravalvular regurgitation, could be registered, if the loose thread was in the posterior part of the ring. If the threads were lossened up in the lateral sides of the ring, there was only a slightly abnormal disc movement inspite of a considerable ring movement, since the disc moved parallel to the transducer. The technic allows an analysis of many pathological mechanisms of the disc movement, and it can explain some of the difficulties which occur during in-vivo registrations of the Björk-Shiley disc valve.

Echocardiography↗
PubMed1979

[Effect of prazosin in therapy-resistant chronic cardiac failure (author's transl)].

In addition to standard treatment with digitalis and diuretics prazosin (20 mg/d) and placebo were given to 14 patients with chronic therapy-resistant cardiac failure mainly of stage III for periods of 6 weeks each. Cardiac frequency, blood pressure, cardiac volume, pulmonary artery pressures and cardiac minute volume were assessed at rest and during physical exercise. Body weight, congestive changes in the chest radiograph, oedema and complaints were evaluated. During the acute trial using 2 mg of prazosin a significant increase of cardiac minute volume was demonstrable at rest and during exercise (2 P less than 0.05). After administration for 6 weeks cardiac minute volume increased from 3.2 to 4.0 l/min at rest and from 6.9 to 8.0 l/min during exercise (2P less than 0.005; n=12). There was a noticeable decrease of cardiac size from 1440 to 1306 ml/1.73 m2 (2 P less than 0.02). Haemodynamic improvement paralleled the decrease of complaints which was equivalent to an improvement of half to one stage of the New York Heart Association. In severe cardiac failure prazosin has thus an additional therapeutic effect beyond digitalis and diuretics.

Adult↗
PubMed1979

[The meaning of the systolic progression of the mitral valve for the outflow tract obstruction in hypertrophic obstructive cardiomyopathy (HOCM). Studies by means of a valve model].

We constructed two valve models in order to investigate the cause of SAM of the mitral valve and the cause of the outflow tract obstruction in HOCM. With model 1 we were able to demonstrate that a subvalvular obstruction created a SAM of the mitral valve, there was also a pressure gradient distal to the obstruction, the valve itself did not create any obstruction. With model 2 we demonstrated that three causes were responsible for an outflow tract obstruction: 1. A narrow outflow tract even after removal of the mitral valve. 2. A position of the mitral valve close to a protruding septum and relatively short chordae tendineae. 3. A SAM of the mitral valve with apposition to the septum due to a Venturi effect. We were able to create a typical bisferiens poststenotic pressure curve in presence of a monophasic prestenotic curve. We conclude from our investigation that for the SAM of the mitral valve as well as for the outflow tract obstruction different anatomic structures may be responsible, which cause simular hemodynamic abnormalities. These abnormalities are most prominent in HOCM but not necessarily linked with this disease.

Cardiomyopathy, Hypertrophic↗
PubMed1978

[Echocardiography].

Explore the source record for details and available documents.

Echocardiography↗
PubMed1976

[Cyclic AMP and plasma renin activity in renal vein blood after amitryptiline, theophylline, furosemide and beta adrenergic blocking substances (author's transl)].

The influence of amitryptiline, theophylline and furosemide on the concentration of cyclic-AMP and plasma renin activity (PRA) was investigated in renal vein plasma. Additionally, the stimulating effect of furosemide on the PRA after application of the beta-adrenergic receptor antagonists propranolol and practolol and the cyclic AMP concentration in the plasma were measured. All drugs were given intravenously. After amitryptiline cyclic-AMP concentration increased about 1.5-fold compared with the basal value,PRA was not altered. After theophylline cyclic-AMP concentration increased about 1.2-fold, PRA 2.0-fold compared with the basal value, PRA was not altered. After theophylline cyclic-AMP concentration increased about 1.2-fold, PRA 2.0-fold coa increased within 7 min and no further increase was observed till the 15th min. After practolol cyclic-AMP concentration and PRA decreased about 20% compared with the basal value within 10 min. The stimulating effect of subsequently applied furosemide on PRA was not altered, but the cyclic-AMP concentration was not changed in this time by furosemide. After propranolol cyclic-AMP concentration and PRA decreased about 20% compared with the basal value. The cyclic-AMP concentration was not influenced by the following furosemide application, in agreement with the findings after practolol, however, PRA could be stimulated only in 36% of these patients under beta-receptor blockade. Our results show that changes of the concentrations of cyclic-AMP and of PRA are independent of each other. An elevated intracellular cyclic-AMP level due to the inhibition of phosphodiesterase is as a single factor unable to stimulate renin release. Our results give no evidence of a direct involvement of the adenylcyclase-system in the mechanism of renin release. The effect of propranolol and practolol on the basal value of PRA and cyclic-AMP is equal. The different influence of 10 mg propranolol and 20 mg practolol on the stimulating effect of 40 mg furosemide on the PRA can be interpreted as a dosage problem.

Adrenergic beta-Antagonists↗
PubMed1976

[Treatment of essential hypertension with propranolol (author's transl)].

Effect of long-term administration of propranolol was studied in 90 unselected patients with essential hypertension. At a dose of 180 and 360 mg daily it dropped the blood pressure to at least 155/95 mm Hg in 31 patients (34.4%). Those who responded to propranolol had lower systolic and diastolic blood pre-treatment pressures than those who failed, were younger by an average of eight years, and in no case had decreased plasma-renin activity and demonstrated greater plasma-renin activity after furosemide. After a titration phase with increasing doses of propranolol those who responded were treated in a crossed double-blind test with propranolol or placebo. There was a significant difference in systolic blood pressure (standing and lying) and diastolic pressure (standing) between the two. There was also a highly significant difference in heart rate. During chronic beta blockade the basal and stimulated plasma-renin activity fell. But percentage stimulation of renin secretion was fully maintained. However, aldosterone response was decreased. Serum potassium rose slightly but significantly, cAMP 24-hour urine excretion fell significantly. Electrolyte excretion did not differ between the two treatment periods.

Adult↗