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Biomedical subjects

E Sauer

Publications and source records attributed to E Sauer.

At least 19 recordsLinked to original sources
PubMed2005

Quantification of aortic valve area and left ventricular muscle mass in healthy subjects and patients with symptomatic aortic valve stenosis by MRI.

MRI allows visualization and planimetry of the aortic valve orifice and accurate determination of left ventricular muscle mass, which are important parameters in aortic stenosis. In contrast to invasive methods, MRI planimetry of the aortic valve area (AVA) is flow independent. AVA is usually indexed to body surface area. Left ventricular muscle mass is dependent on weight and height in healthy individuals. We studied AVA, left ventricular muscle mass (LMM) and ejection fraction (EF) in 100 healthy individuals and in patients with symptomatic aortic valve stenosis (AS). All were examined by MRI (1.5 Tesla Siemens Sonate) and the AVA was visualized in segmented 2D flash sequences and planimetry of the performed AVA was manually. The aortic valve area in healthy individuals was 3.9+/-0.7 cm(2), and the LMM was 99+/-27 g. In a correlation analysis, the strongest correlation of AVA was to height (r=0.75, p<0.001) and for LMM to weight (r=0.64, p<0.001). In a multiple regression analysis, the expected AVA for healthy subjects can be predicted using body height: AVA=-2.64+0.04 x(height in cm) -0.47 x w (w=0 for man, w=1 for female).In patients with aortic valve stenosis, AVA was 1.0+/-0.35 cm(2), in correlation to cath lab r=0.72, and LMM was 172+/-56 g. We compared the AS patients results with the data of the healthy subjects, where the reduction of the AVA was 28+/-10% of the expected normal value, while LMM was 42% higher in patients with AS. There was no correlation to height, weight or BSA in patients with AS. With cardiac MRI, planimetry of AVA for normal subjects and patients with AS offered a simple, fast and non-invasive method to quantify AVA. In addition LMM and EF could be determined. The strong correlation between height and AVA documented in normal subjects offered the opportunity to integrate this relation between expected valve area and definitive orifice in determining the disease of the aortic valve for the individual patient. With diagnostic MRI in patients with AS, invasive measurements of the systolic transvalvular gradient does not seem to be necessary.

Aged↗
PubMed2002

[Selective increase of ventricular pacing threshold with complete exit block following DC cardioversion in a patient with a dual chamber pacemaker].

We report the case of a 78-year old patient with a dual chamber pacemaker, who was admitted for cardioversion of atrial tachycardia. Transthoracic DC shock of 160 J was followed by transient loss of ventricular capture with complete exit-block and severe nodal bradycardia. Subsequent analysis of stimulation thresholds revealed a marked rise in the ventricular threshold only, whereas atrial threshold was unchanged. The selective dysfunction of ventricular capture is most likely caused by current-induced tissue damage at the electrode-endomyocardial interface by preferential shunting of high electrical energy into the ventricular lead as compared to the atrial lead. High output pacing prior to elective DC cardioversion is recommended to ensure consistent capture, particularly in pacemaker-dependent patients, and careful evaluation of pacemaker function after shock delivery should performed.

Aged↗
PubMed1996

Nitric oxide attenuates the release of endothelium-derived hyperpolarizing factor.

BACKGROUND: The contribution of the endothelium-derived hyperpolarizing factor (EDHF), proposed to be a cytochrome P450-derived metabolite of arachidonic acid, to endothelium-dependent dilatation under physiological conditions has yet to be established, because its effect can be detected only after inhibition of NO synthase and cyclooxygenase. The possibility that NO exerts a feedback inhibition on EDHF formation was studied in isolated perfused arterial segments. METHODS AND RESULTS: Under combined blockade of NO synthase and cyclooxygenase, the EDHF-mediated vasodilatation elicited by receptor-dependent agonists in rabbit carotid and porcine coronary arteries was significantly attenuated by the NO donors C87-3786 and CAS 1609. The endothelium-independent dilatation elicited by isoproterenol was not altered by either NO donor. In NG-nitro-L-arginine-treated carotid artery segments, C87-3786 significantly attenuated the acetylcholine-induced increase in 6-keto-prostaglandin F1 alpha release, which was taken as an index of arachidonic acid liberation. In parallel experiments using cultured human endothelial cells, C87-3786 attenuated the Ca2+ response to bradykinin. The release of EDHF from a luminally perfused porcine coronary artery was detected by recording the membrane potential of downstream-situated cultured rat aortic smooth muscle cells. The NO donor C87-3786 had no effect on the hyperpolarization elicited by preformed EDHF but markedly inhibited its release from bradykinin-stimulated donor segments. CONCLUSIONS: These findings indicate that under physiological conditions, the production of EDHF is damped by NO. Therefore, it follows that when NO synthesis is impaired, alleviation of this intrinsic inhibition may, at least in part, maintain endothelial vasodilator function.

6-Ketoprostaglandin F1 alpha↗
PubMed1990

[Comparative anatomy of the tongue of Pan troglodytes (Blumenbach, 1799) and other primates. II. Findings in other primates].

This 2nd part of our studies shows that the papilla foliata is fully developed in Pan, Cebus, and Macaca; in Prosimians the papilla foliata is well developed in Lemur and Chirogaleus. In Galago crassicaudatus, this papilla is missing. Among 3 individuals of Microcebus, the papilla foliata was differently developed: in 2 cases, the tongue exhibited only 2 on both sides and a very low folia. Taste buds were found in the epithelium of only one side of each folium. In the 3rd case, the folia of the papilla were developed only on one side of the tongue, whereas, on the other side, a typical papilla was missing. Instead of the papilla, the tongue of the same animal exhibited a hillock-like structure; it is a gustatory hillock which exhibited many taste buds. There were 3 gustatory hillocks in all of the specimens of Tupaia glis; they are situated on both sides of the tongue.

Animals↗
PubMed1990

[Comparative anatomic studies of the tongue of Pan troglodytes (Blumenbach, 1799) and other primates. I. The chimpanzee tongue].

This study was carried out on a comprehensive collection of tongues of Pan troglodytes. Material of tongues of Tupaia glis, Microcebus murinus, Chirogaleus major, Lemur catta, Galago crassicaudatus, Cebus apella, and Macaca mulatta were used for comparison of the different stages of the development of the papilla foliata. The tongue of Pan exhibits longitudinal growth correlated with the growth of length of the jaws and individual age. A typical foramen caecum as it occurs in man was gross anatomically not recognizable. Seldom a small circular depression appeared in the midline close to the papilla circumvallata centralis which could be the remnant of the foramen caecum. There is a remarkable accumulation of papillae filiformes and fungiformes at the apex linguae; the same seems to be true for other genera of primates. It is self-explanatory that the accumulation of papillae makes the tip of the tongue a particularly sensitive area; this has been found to be true even in man. One specimen of the prenatal age just before term was studied. It exhibited remarkably elongated, thread-like papillae, their function is unknown as yet. They are no longer present in a newborn specimen of 4 d of age. In the aboral part of the dorsum linguae, a special kind of papillae occur; they are flat lobes which carry moderately elongated, tiny processes at their free margin. The function of these papillae is unknown; taste buds are absent.

Animals↗
PubMed1986

Radionuclide assessment of a normal left ventricular response to exercise in patients without evidence of heart disease.

The aim of this study was to define normal left ventricular performance at rest and during supine bicycle exercise with equilibrium radionuclide ventriculography in a normal population other than young healthy volunteers. Thirty-one patients (mean age 45 years +/- 9 SD) with chest pain of varying origin and no evidence of heart disease proven by means of noninvasive and invasive techniques were studied. Left ventricular ejection fraction (LVEF) at rest averaged 0.64 +/- 0.07 SD and increased with peak exercise to 0.73 +/- 0.08 SD (P less than 0.005). Change in LVEF from rest to maximum exercise ranged within 0-0.19. Six patients (19%) failed to augment LVEF with exercise to more than 0.05; none of the patients dropped LVEF during exercise. Multivariate analysis revealed no significant predictors of LVEF response to exercise. However, there was a tendency that resting LVEF and enddiastolic volume index with exercise might influence LVEF response to exercise. Peak left ventricular ejection rate (LVER) at rest averaged 3.3 s-1 +/- 0.6 SD and increased to 5.1 s-1 +/- 1.1 SD (P less than 0.005) with exercise. Peak left ventricular early filling rate (LVFR) was 2.8 s-1 +/- 0.6 SD at rest and was measured 5.5 s-1 +/- 1.3 SD at maximum exercise (P less than 0.005). Left ventricular enddiastolic volume (EDV) did not change significantly from rest to maximum exercise, whereas left ventricular endsystolic volume (ESV) decreased to 79% +/- 19 SD (P less than 0.01) of the value at rest.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

Higher density of mental capacities in the left cerebral hemisphere of man: a quantitative investigation in children with localized cerebral lesions.

51 children with localized cerebral lesions were investigated with the British Ability Scales, Wechsler test, Porteus Mazes, Conners Teacher Rating Scale, and computerized tomography. The extent of the lesions was quantitatively determined. The IQ was 10 points lower in the left hemispheric lesions, although the right hemispheric lesions were larger. When corrected for size of lesions, the IQ is 17 points higher (p less than 0.05) in children with right than with left hemispheric early lesions. The children with left hemispheric lesions had also significantly more behavioural problems (Conners Scale). Children with bilateral lesions had 15 points lower IQ than those with unilateral lesions, although from the slightly larger extent one could expect only 3 points difference. There was no influence of hemiparesis or of epilepsy of the IQ independent of the extent of lesion. There was more plasticity of the hemisphere than of the lobes as shown by Wisconsin Card Sorting data. The higher density of mental capacities in the left cerebral hemisphere of man is explained by more efficient programs, and more dense packing of functions due to more training of the left cerebral hemisphere.

Adolescent↗
PubMed1985

A quantitative relationship between the extent of localized cerebral lesions and the intellectual and behavioural deficiency in children.

In an investigation of 51 children with localized forebrain lesions (25 left hemispheric, 15 right hemispheric and 11 bilateral) a significant relationship between the extent of the cerebral lesion (quantitatively determined by means of computerized tomography scans) and the IQ was found, but only in children with lesions after age 5: there was a diminution of 3 (British Ability Scales and Porteus Mazes) to 4 (Wechsler test) points of IQ for a 1% increased brain lesion. There was no correlation between the extent of the lesion and IQ in children with early lesions. The IQ of the children with early lesions (up to year 4) was significantly lower than that of children with later lesions of the same extent. There was a highly significant correlation between behavioural problems (assessed by Conners Teacher Rating Scale) and diminution of IQ. There was a significant correlation between the extent of lesion and behavioural problems in lesions after year 5, but not in early lesions. While the correlation between intellectual-behavioural impairment and the extent of cerebral lesions can be explained by multiple localisation of functions, the lack of this correlation in early lesions and the more severe impairment by earlier lesions may be due to an interaction of brain development with social and lesional factors. Since each part of the brain may act as a stimulus for the development of other parts, even small differences in the lesions (and/or in the environment) may result in large behavioural differences (hypothesis of the developing brain as an amplifier for differences in the stimuli).

Brain Damage, Chronic↗
PubMed1985

Prenalterol: a partial beta 1-adrenoceptor agonist or a beta-blocker with intrinsic activity?

Hemodynamic studies have demonstrated a significantly reduced beta 1-adrenoceptor stimulating effect of prenalterol compared to dobutamine suggesting a partial agonism on the receptor. In order to prove this hypothesis we administered 80 micrograms/kg of prenalterol within 5 minutes in 8 healthy volunteers during a continuous infusion of dobutamine (15 micrograms/kg/min). In addition to heart rate, blood pressure and the double product, the systolic time intervals QS2I, PEP and LVET and the echocardiographically determined parameters FS and Vcf were measured for evaluation of ventrical function. The injection of prenalterol caused a distinct attenuation of the cardiostimulating effects of dobutamine: there was a prompt fall in heart rate and systolic blood pressure and a typical negative inotropic effect on the parameters of left ventricular function. In the experimental conditions selected, the effects of prenalterol were those of a beta-sympatholoytic agent. Prenalterol should therefore be classified as a partial beta 1-adrenoceptor agonist or as a beta-blocking agent with pronounced intrinsic sympathomimetic activity. The beta 1-stimulating potency of prenalterol amounts to about 60% of a full agonist.

Adrenergic beta-Agonists↗
PubMed1983

[Radionuclide ventriculography in coronary heart disease].

Heart function can be investigated non-invasively and without risk for the patient by means of radionuclide ventriculography. Coronary artery disease can be diagnosed with high sensitivity and distinguished from other diseases of the heart with high specificity by typical alterations of heart function as seen in rest and/or exercise scans. The hemodynamic significance of invasively proven stenoses of coronary arteries can de demonstrated and the function and functional capacity of surviving vital myocardium after myocardial infarction can be quantified scintigraphically. The efficacy of medical and surgical therapy can be documented and the course of disease can be followed up.

Coronary Disease↗
PubMed1983

[Delayed atrial excitation following bifocal pacemaker stimulation].

A patient with drug-resistant ventricular tachycardia due to ischemic heart disease with severe left ventricular failure was successfully treated by the implantation of a DDD pacemaker system pacing at a rate of 90 beats/min (overdrive suppression). Additional therapy with high doses of beta-blockers was necessary. The ECG demonstrated a delay of 100 ms between atrial spike and p-wave. The hemodynamic effects of this ineffective atrial contraction were assessed by jugular venous puls tracing, phonocardiography, echocardiography, and radionuclide-ventriculography. The desired positive effects of physiological pacing could only be achieved by further prolongation of the A-V interval by these 100 ms. This observation shows that, with DDD pacemakers, AV intervals of varying length may be necessary with VAT or VDD and DVI modes in individual cases.

Echocardiography↗
PubMed1980

[Myocardial scintigraphy and radionuclide ventriculography in myocardial infarction (author's transl)].

149 patients with acute (n = 75) myocardial infarction and 74 post-infarctions, angiographically confirmed, were investigated by 201T1 myocardial scintigraphy and subsequent radionuclide ventriculography. Quantitative evaluation of the scintigram showed 201T1 storage defects in 92% in the acute stage in 79% in the later stage. The sensitivity of identification of the posterior wall infarction was consistently markedly less than for anterior wall infarctions and could not be increased by additional application of 99mTc methylene diphosphonate. By the combined application of myocardial scintigraphy and radionuclide ventriculography the functional effects of the infarction can be described non-invasively.

Acute Disease↗
PubMed1980

[Orally active vasodilators in the management of chronic treatment-resistant cardiac failure (author's transl)].

The acute haemodynamic effects of 40 mg isosorbide dinitrate (10 subjects), 4 mg prazosin (20 subjects) and 50 mg dihydralazine (8 subjects) were compared in 24 patients with the clinical picture of chronic therapy-resistant cardiac failure (NY Heart Association stages III-IV). There was a fall in left-ventricular filling pressure of about 15% and right-atrial mean pressure of 21 and 24%, respectively, with isosorbide dinitrate and prazosin, while there was no change with dihydralazine. Cardiac output rose by 23% with dihydralazine and 20% with prazosin, but remained unchanged with isosorbide dinitrate. These data indicate that a reduction in pulmonary and systemic-venous congestion due to chronic decompensated cardiac failure can be achieved with isosorbide dinitrate and prazosin, while cardiac output can be improved only with prazosin and dihydralazine.

Adult↗