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Biomedical subjects

T Linderer

Publications and source records attributed to T Linderer.

50 records · Page 3Linked to original sources

Measurement of coronary sinus blood flow by fiber-optic laser Doppler anemometry.

The Doppler shift of a laser has been used to measure the velocity of blood in the coronary sinus of the dog. The laser was delivered along a fine fiber-optic probe, which was also used to receive the reflected light. The Doppler shift was measured from the output of a digital spectrum analyzer. This measurement, proportional to the velocity of blood, was correlated with the blood flow measured by an electromagnetic flowmeter. Studies were performed on 112 successful maneuvers in eight consecutive anesthetized dogs. In the minimally damped electromagnetic flow traces, the correlation between coronary sinus blood flow velocity and coronary sinus blood flow was high (r greater than 0.95). This measurement will give absolute flow values only if the exact dimensions of the coronary sinus are known. The linear relationship of coronary sinus velocity and flow supports the postulate that coronary sinus dimension remains similar during normal and high flows. This technique, fiber-optic laser Doppler anemometry, is an accurate measure of relative coronary sinus blood flow. It is suitable for use in human coronary sinuses, especially to monitor the effect of interventions.

Animals↗

[Systemic thrombolysis with short-term streptokinase infusion in acute myocardial infarct].

Within 6 hours after the onset of acute myocardial infarction, 93 patients received a brief high-dose intravenous infusion of streptokinase, 49 patients received 500,000 IU within 30 min and 44 patients received 1,500,000 IU within 60 min. 26 patients had angiography in the acute phase, after 24 hours, and in the 4th week; 52 patients had angiography in the 4th week only; and 15 had no angiography. 7 patients died in hospital and 6 suffered a nonfatal reinfarction. There were no complications with bleeding. In 52% of cases, reopening of an occluded infarct vessel was achieved within 1 hour of the beginning of treatment. During the 4th week after infarction a patent infarct vessel was found in 84%, and 58% had a residual stenosis less than 70%. In contrast, in a control group that received no streptokinase treatment, 25% had a patent infarct vessel and 4% had a residual stenosis less than 70%. Indicative for salvage of ischemic myocardium are a significant improvement in local contraction disorders between the acute phase and the 4th week and a significant correlation between infarct size in the 4th week and beginning of treatment after onset of symptoms. 1. It may be concluded that: brief intravenous infusion of streptokinase results in restoration of blood flow in an infarcted coronary artery in a high percentage of cases; the shorter thrombus-lysis time with intracoronary streptokinase infusion could be made up for by the earlier initiation of intravenous streptokinase treatment; and a conclusive randomized trial is needed to ascertain the true impact of a brief high-dose intravenous infusion of streptokinase on mortality and morbidity following acute myocardial infarction.

Adult↗

[Intravenous streptokinase infusions in acute myocardial infarction. Restoring patency of occluded thrombotic coronary vessels (author's transl)].

Intravenous treatment over 30 minutes with 500 000 U streptokinase was given to 21 patients with acute myocardial infarction. Serial measurements of serum CK-MB activity made recanalisation of the infarcted artery likely in 3 patients. Selective coronarography was performed in 18 patients during the acute infarction phase. Angiographic follow-up investigations were done 24 hours and after 3 weeks. In 3 cases only subtotal occlusion of the infarcted coronary artery was seen during the acute phase. A thrombus demonstrated in two patients could be lysed. In 8 out of 15 patients with complete coronary artery occlusion the infarcted vessel was reopened 20-60 minutes after onset of intravenous streptokinase infusion. In a further 4 patients recanalisation was observed 60-140 minutes after passing a guide wire or during an additional intracoronary infusion of streptokinase. The infarcted vessel remained occluded in 3 patients, one of whom died following myocardial rupture. In 12 patients with recanalisation of the infarcted artery during the acute phase a premature maximum of serial CK-MB serum activity was seen after 13.5 +/- 2.9 hours in comparison with 20.9 +/- 5.3 hours in 122 patients treated conventionally. Serial enzyme determinations allow indirect conclusions as to a rapid recanalisation of an infarcted blood vessel.

Angiocardiography↗

[The segmental early relaxation phenomenon; its incidence and angiographic appearance (author's transl)].

Amongst one hundred patients examined radiographically, segmental early relaxation (SERP) of the antero-lateral wall of the left ventricle was observed in 21 cases; in 17 cases this was associated with a significant stenosis of the anterior descending branch of the left coronary artery. The reversibility of this phenomenon produced by vaso-dilators or by aorto-coronary by-pass operations with consequent increase in oxygen supply, as well as the frequency of this phenomenon in coronary disease suggests that it is due to mild, local hypoxia. On this view, SERP has clinical significance as an angiographic indicator of local oxygen deficit. Other possible causes are discussed and the findings compared with those reported in the literature.

Adult↗