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Biomedical subjects

J Dittrich

Publications and source records attributed to J Dittrich.

At least 19 recordsLinked to original sources
PubMed1995

Measurement of absolute epicardial coronary artery flow and flow reserve with breath-hold cine phase-contrast magnetic resonance imaging.

BACKGROUND: Noninvasive measurement of absolute coronary arterial flow and coronary flow reserve would be of considerable use in the diagnosis and management of patients with coronary artery disease. Phase-contrast magnetic resonance imaging (MRI) has been used to measure flow in a variety of vessels. The goal of the present study was to determine if MRI measurements of coronary artery flow in a single breath-hold can be used to determine flow reserve and the severity of pericardial stenosis. METHODS AND RESULTS: In eight mongrel dogs, a closed chest model of partial left anterior descending coronary artery (LAD) occlusion was created. Coronary flows in the left circumflex artery (LCx) and LAD were measured at rest and during adenosine infusion using velocity-encoded, breath-hold MRI and perivascular ultrasound (US) flowmeters. MRI measurements of absolute coronary flow and coronary flow reserve were highly correlated with US (r = .96 and .94, respectively). Flow reserve measured in the constricted LAD was significantly lower than that in the unconstricted LCx by both US (P = .002) and MRI (P = .011). CONCLUSIONS: MRI measurements of coronary flow and flow reserve were in good agreement with US measurements. In addition, MRI measurements of coronary flow reserve successfully discriminated stenotic from normal vessels. These results indicate that MRI is a useful method for the noninvasive assessment of coronary flow and stenosis.

Adenosine↗
PubMed1989

[Application of dipeptidylpeptidase IV in formation of the peptide bond].

According to the increasing importance of enzyme catalysed peptide synthesis the capability of the protease dipeptidyl peptidase IV is shown to form the peptide bond. To our best knowledge, it's the first time that has been used successfully proline as one of the amino acids. The formation of the peptide bond is kinetically controlled. Free amino acids have been used as nucleophiles. The reaction media contain 50 vol.-% glycerol. A first approach to a kinetic treatment is shown.

Amino Acid Sequence↗
PubMed1979

[Pacemaker's twiddler syndrome (author's transl)].

This report demonstrates the results of five observation of the Pacemaker's-twiddler-syndrome, which will not necessarily end in the complete malfunction of the pacemaker unit. Therefore we classify the Pacemaker's-twiddler-syndrome as a partial and a complete form. The partial form is characterized by still effective cardiac stimulation, whereas the complete form can not stimulate the heart muscle because of the retracted electrode. Also methods of early detection and prevention of the Pacemaker's-twiddler-syndrome are discussed.

Aged↗
PubMed1979

[Pharmacological treatment of chronic arterial occlusive disease (author's transl)].

Two thirds of the patients with peripheral arterial occlusive disease have to be treated conservatively, for only up to 30% can be revascularized by operative methods. Using the pharmacological differential treatment the grade of compensation and localization of the obliterative process has to be considered. Ignoring the usual basic therapy (elimination of heart failure and pathological bradycardia, systemic walking-exercise, anticoagulation etc.) intrafemoral long-term application of energetic phosphate (i.e. nucleotid-nucleosid-mixtures) leads to a positive result in nearly two thirds (n = 97 legs) with a degree of II to IV of Fontaine. Whereas the snakes' encyme Ancrod with the effect of defibrination was successful in almost 70% of the patients with arterial insufficiency (n = 45) including the degree II B (painless walking-distance under 100 meters). Energetic phosphates, applied to the arteria femoralis, are most successful in degree II with claudication intermittens. Ancrod should be used respectively for patients with pain during rest. These results are discussed with respect to compensation and localization of arterial occlusive disease, acute and chronic measurements of the hemodynamics by use of Doppler ultrasound and strain gauge plethysmography and with respect to variation of the concentration of the metabolic parameters lactate and pyruvate--the latter when defibrination was performed.

Aged↗
PubMed1979

Paroxysmal hemipareses in childhood.

The authors report three patients suffering since infancy from transient attacks of paresis. The flaccid pareses most frequently affect the extremities in a hemiplegic fashion, but occasionally there is monoparesis or quadriparesis. The laterality and degree of the paresis are variable. Conciousness is always preserved, and in two cases attacks were preceded by ocular motor disturbances (skew deviation, nystagmoid jerks and conjugate deviations). Exceptionally, the transient hemiparesis may be preceded by a grand mal epileptic fit, though they are more likely to appear sporadically and independently of the paretic changes. In the interparoxysmal periods the children showed pronounced hypotonia, hyperkinetic extrapyramidal features and oligophrenia. Neuroradiological procedures have excluded brain anomalies of vascular or other aetiology and simple biochemical analyses were negative. EMG during paretic periods have revealed central motor neuron lesions, while EEG demonstrated non-specific paroxysmal features. A brain-stem dysfunction in the aetiology is postulated.

Adolescent↗