The pre-stenotic Doppler shift signature.

In two series of measurements the Doppler shift signatures of 10 healthy volunteers were studied at varying distances proximal to a total reflection site, in order to describe parameters which are predictive for downstream lesions. Characteristic changes both in amplitude and time parameters were found; the most marked changes being the abolishment of a DC-component for monophasic signatures, the development or the augmentation of early diastolic reverse flow amplitudes together with a highly significant reduction in the signatures' systolic deceleration time. Maximum changes however tended to be localized at 2 to 4 centimeters upstream from the reflection site.

How useful are acceleration- and deceleration-based Doppler indices? A trial on patients with percutaneous transluminal angioplasty.

The usefulness of indices commonly used in Doppler sonography is limited; the aim of this study was to investigate if inclusion of systolic acceleration and deceleration patterns in Doppler indices will result in practical diagnostic advantages. Systolic delay time index (SDTI) and height-width index (HWI) are compared to Gosling's pulsatility index (PI) and to PI-based damping factors (DF) in patients with isolated lesions in the distal superficial femoral artery before and after percutaneous transluminal angioplasty (PTA). Before PTA, all indices distal to the lesion differ significantly from proximal indices.

[Lack of fatigue of the musculature in patients after immobilization--a paradox?].

The isometric strength of knee extensors was measured in patients six weeks after cruciate ligament surgery over a contraction period of 30 sec. The characteristics of the graph obtained form the measurement system were compared to the graphs of uninjured knee extensor muscles. Apart from strength reductions, as expected for atrophic muscle, the pattern of the strength graph led to the impression that these muscles did not fatigue during prolonged contraction.

[The value of 31 P nuclear magnetic resonance spectroscopy in follow up of Fontaine stage IIb peripheral arterial occlusive disease].

The method of nuclear magnetic resonance (NMR) spectroscopy compared to the parameters absolute-, pain-free walking distance and ankle/arm coefficient in Doppler pressure was used for observation of patients with peripheral arterial occlusive disease stage IIb according to Fontaine. While the classic parameters (walking distances, ankle/arm coefficient) described a homogenous group, NMR-spectroscopy parameters showed marked inter- and intraindividual variations during exercise. Further studies on high magnetic power fields, exercise patterns and muscle recreation analysis have to be carried out to develop a reliable system of non invasive muscle energy monitoring in vascular diseases.

[What does 31 phosphorus magnetic resonance spectroscopy measure?A validation in healthy probands].

With 31P nuclear magnetic resonance spectroscopy skeletal muscle metabolism can be measured noninvasively. Aim of this study was to investigate intraindividual reproducebility, interindividual variability, and the correlation of the NMR parameters PCr, alpha-, beta-, gamma-ATP to graded exercise. Reproducebility and variability of PCr values were comparabel to changes of the pH value.

[Changes in the ultrasound power spectrum due to concentric stenoses of the femoral artery of the dog].

An artificial stenosis model consisting of a revolving centric cylinder with six boreholes (10-60% diameter reduction) was implanted in the superficial femoral artery of anaesthezised beagles (n = 10). Range gated pulsed Doppler signals were recorded at 7 sites between three diameters upstream to ten diameters downstream the Angle corrected parameters derived from the contour of spectral lines between 3 and 21dB on both sides of mode frequency were calculated for different time windows. Two groups of dogs could be distinguished.

Myocardial performance and metabolism in non-ketotic, diabetic rat hearts: myocardial function and metabolism in vivo and in the isolated perfused heart under the influence of insulin and octanoate.

The influence of a non-ketonic, chronically diabetic state (60 mg/kg streptozotocin) on cardiac function and metabolism was studied under in vivo conditions by inserting a Millar-tip catheter into the left ventricle and in the model of the isolated perfused heart. In vivo heart rate and maximal left ventricular systolic pressure were reduced after a diabetes duration of 4 and 12 weeks. The maximal rise and fall in left ventricular pressure progressively declined with the duration of diabetes.