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Biomedical subjects

R Lichtenberg

Publications and source records attributed to R Lichtenberg.

At least 37 records · Page 2Linked to original sources

Echocardiographic and phonocardiographic assessment of the St. Jude cardiac valve prosthesis.

Forty-three consecutive patients with a St. Jude mitral, aortic, or combined prosthesis were studied by simultaneous phonocardiography and echocardiography. Twenty-eight patients had a mitral prosthesis, 20 an aortic prosthesis, and five had both. No opening click was recorded in any patient; however, a loud aortic or mitral closing click was recorded in all 43 patients. In patients with St. Jude mitral valve prosthesis, an echo-free space separated the two leaflets during diastole; seven of these also had a mid-diastolic closing and late diastolic reopening motion; two of the seven had an associated closing mid-diastolic click. A mid-diastolic rumble was recorded in six of 28 patients with St. Jude mitral valve prosthesis. In patients with a St. Jude aortic valve prosthesis, left atrium leaflet motion was recorded in 17 of 20 patients and was indistinguishable in appearance from echocardiograms obtained with various eccentric monocusp valves. In addition, we report one case of malfunction of a St. Jude mitral valve and one case of a paravalvular leak diagnosed by echophonocardiography. We concluded that the St. Jude cardiac prosthesis has variable normal phonocardiographic-echocardiographic patterns. Knowledge of these variable patterns is important in assessing patients with suspected malfunction of a St. Jude cardiac prosthesis.

Adult↗

Myocardial ischemia after left ventriculography: pathophysiology and clinical significance.

The effects of contrast material on the left ventricular end-diastolic pressure (LVEDP) were evaluated in three groups of patients. Twenty patients (group I) with severe coronary artery disease (CAD) were found to have a change in LVEDP greater than or equal to 20 mm Hg; 15 patients (group II) with severe CAD had elevation of LVEDP less than 20 mm Hg; ten patients (group III) with normal coronary angiograms had a rise in LVEDP less than 20 mM Hg. The change in LVEDP was higher in group I than in groups II and III (P less than 0.005). Nineteen patients (95%) in group I complained of angina pectoris or had ST segment depression (or both) after ventriculography in association with the sharp increment in LVEDP. Angina or ST depression were seen in only two patients (13%) in group II and none in group III. We conclude that 1) elevation of LVEDP of 20 mm Hg or more after ventriculography may be seen in patients with severe CAD (most likely secondary to direct depressant effect of the contrast material on the myocardium) and 2) the abrupt and marked rise in LVEDP may produce myocardial ischemia due to reduction of coronary blood flow, especially to the subendocardial layer.

Aorta↗

Rate of metabolism of norethisterone in women from different populations.

The rate of metabolism of orally administered norethisterone was compared in fourteen centres by measuring plasma levels of the steroid by radioimmunoassay at varying times after oral administration of a 1 mg dose. The inter-centre differences were of the same order as the intra-centre differences. Variations in metabolism appeared not to be due to variations in body size.

Adult↗

[Short-term dialyses using the Rhodial system].

In order to achieve an optimal rehabilitation of patients undergoing dialysis an abbreviation of the periods of dialysis with unchanged frequency of dialysis is necessary, when the patients are widely free of symptoms. Using conventional dialysators we only conditionedly succeed in shortening the time and this is not without any problems. The development of the acrylonitril-membrane (RP 6) and the use in the closed system (Rhodial-system) allows an extreme shortening of the time. It is reported on the use of the Rhodial-system since June 1975. The efficiency of the dialysator (RP 6) in the region of the middle molecules makes possible periods of dialysis of 3 times 3 hours a week in oligo-anuric patients. It is reported on the results of more than 3,000 dialyses in the behaviour of the micromolecular substances, of haemoglobin and haematocrit, blood pressure, polyneuropathy as well as of the subjective behaviour of the patient. These results led to abandoning dialyses with conventional membranes, as far as they transgress the time of dialysis of 9 hours a week.

Blood Pressure↗