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Biomedical subjects

G Trieb

Publications and source records attributed to G Trieb.

At least 37 records · Page 2Linked to original sources
PubMed1982

[Hemodynamics of the St. Jude Medical aortic prosthesis in comparison to the Björk-Shiley and Lillehei-Kaster prostheses].

Pre- and postoperative hemodynamic data in 10 patients in whom the aortic valve was replaced by a St. Jude Medical (SJM) prosthesis are compared with those in 29 patients who received a Lillehei-Kaster tilting disk (LK) valve prosthesis and 11 patients with a Björk-Shiley tilting disk (BS) valve prosthesis. The SJM aortic prosthesis of the small size (A 21) has advantages over the LK and BS types, and it is therefore particularly suited to use in a small aorta. There are also good hemodynamic results for the larger sizes of the SJM prosthesis. As a result of the 85-degree opening angle and the favorable ratio between the inner and outer diameters of the valve (suture ring), there is only minor impedance of blood flow. The SJM aortic prosthesis thus involves a lesser degree of hemolysis than the BS and the LK. In spite of the promising hemodynamic data, however, long-term findings on the durability of the SJM prosthesis in vivo have not yet been published. It therefore seems to us justifiable, especially where the aorta is large, to continue to use BS prostheses.

Aged↗
PubMed1981

Influence of heart rate on systolic time intervals: effects of atrial pacing versus dynamic exercise.

The effects of atrial pacing and dynamic exercise in the supine position on systolic time intervals (STI) were compared in 10 normals. In another group of 13 normals, the effect of exercise alone on STI was tested. A linear shortening of electromechanical systole (QS2) and left ventricular ejection time (LVET) with increasing heart rate was demonstrated with right atrial pacing and dynamic exercise in the frequency range between 60 and 140 beats/min. However, the shortening of LVET was significantly less (p less than 0.01) with exercise compared to pacing. This is explained by an increase in left ventricular stroke volume with exercise. The preejection period (PEP) was significantly (p less than 0.001) shortened with exercise, but there was no change with atrial pacing. Thus, changes in heart rate (HR) alone, without changes in the dynamic state of the heart, did not influence PEP. It is suggested that PEP at rest should not be corrected for heart rate. The supine exercise regression equations for correction of heart rate for LVET and PEP differ from both the resting and the upright exercise regression equations. With exercise a frequency correction of STI using regression equations should be abandoned. Instead, uncorrected STI at standard heart rates (e.g., 100, 110, and 130 beats/min) should be taken for comparison. Heart rate standardization should be employed using the formula: Formula (See Text).

Adult↗
PubMed1980

Results after resection of postinfarction left ventricular aneurysms.

Although left ventricular aneurysmectomy (LVA) is a common surgical procedure, the late functional and hemodynamic results have not been well defined. This presentation describes our results with LVA in 135 patients operated between 1969 and 1979. Associated procedures were performed in 57 (42%) including coronary bypass grafting in 50, valve replacement in 5, closure of ventricular septal defect in 2, or combinations of these in 3 patients. One hundred four of the 122 hospital survivors were followed from 2 to 107 months (mean = 37 months). There were 13 hospital deaths (9.6%), 12 late deaths (9.8%) and an actuarial 5-year survival rate of 77%. Clinical improvement of preoperative heart failure occurred in 82%, and of angina in 70%. Only 33 patients (30%) returned to normal work. Bicycle exercise testing in 70 patients showed normal working capacity in 41 (59%). Recatheterization in 49 patients showed no significant changes in left ventricular end-diastolic pressure or cardiac index, and a borderline reduction of the total ejection fraction. Ventricular arrhythmias were detected by long-term ECG in 70% of all patients after surgery. Of those with preoperative life-threatening arrhythmias, rhythm improvement was noted in 50%, but only 2 of 13 patients were free of arrhythmias after operation. This study demonstrates a greater frequency of postoperative symptomatic and functional improvement as compared to hemodynamic and ECG improvement. Ventricular tachyarrhythmias originating from post-infarct scars increased intra- and postoperative risk and aneurysmectomy alone is considered insufficient for treatment of these disturbances. Further electrophysiologic investigations are needed and additional surgical measures may be necessary to improve the subset of patients with life-threatening arrhythmias.

Adult↗
PubMed1980

[Potassium hydrogen phosphate induced nephropathy in the dog. II. Glomerular alterations (author's transl)].

A disseminated atrophy of the proximal tubule accompanies K2HPO4-induced nephropathy in dogs. These pathologic processes cause glomerular changes that pass through different inflammatory stages and terminate in glomerular sclerosis. Experimental animals, design of the experiment and methods have been described [15]. During the 14-week study we determined the amount of urine (24 hours), protein (mg/dl), protein excretion (mg protein/24 hr) and the macro- and microprotein fraction in the urine by SDS-polyacrylamide gel electrophoresis. Clinical examinations were at 15, 66, and 85 days. Beagle dogs treated with 0.8 g K2HPO4/kg body weight developed significant glomerular selective and unselective protienuria. During the experiment the macroproteins in the urine decreased markedly, and at the last examination (day 85) glomerular proteinuria was no longer detectable by electrophoresis. Morphologically, there were only slight glomerular changes in the biopsy material taken at four weeks. Widespread lesions at 14 and 38 weeks were dilatation of Bowman's space, thickening of the basement membrane, increase in mesangial matrix, interposition of non-argentophilic mesangial matrix into the glomerular basement membrane, protein deposits in the mesangium and parietal basement membrane, formation of crescents, shrinkage of the glomeruli with collapse of glomerular tufts, and finally glomerular sclerosis. The parietal epithelial cells contained cytoplasmic areas that were free of organelles and contained microfilamentous and fine-granular material. These areas were close to the capsular basement membrane. Bundles of filaments within parietal epithelial cells had contact with the basement membrane, thus resembling hemidesmosomes. The sequelae of tubular atrophy are retention of glomerular filtrate and dilatation of Bowman's space, followed by compression and shrinkage of the glomerular tufts, and inflammatory processes within the glomerulus. The latter may be characterized as mesangio-sclerosing, mesangio-proliferative, membrano-proliferative, and extra-capillary glomerulonephritis. The decrease of urinary protein excretion towards the end of the experiment may be related to intratubular lysosomal digestion of cellular and amorphous components.

Animals↗
PubMed1979

[Experimental investigations of the content of glycogen in the adrenal gland of the rat after application of dexamethasone, ACTH and a combination of both (author's transl)].

The influence of dexamethasone, ACTH and the combination of both on the glycogen content of the rat adrenal gland was studied. Dexamethasone induces a transient increase of the adrenal glycogen content in a time and dose-dependent manner. The application of ACTH has no effect on the glycogen content. Surprisingly, the increase of the glycogen content induced by dexamethasone is completely blocked by the simultaneous application of ACTH.

Adrenal Glands↗
PubMed1979

Is the excretion of sebum regulated?

The kinetics of sebum excretion on the forehead of volunteers were measured over a period of at least 7 h. The transmission data obtained by the ground glass method were transformed into weight (sebum/cm2). The excretion time function can be described by the equation: w = A . (1 - B . e -C.t). This nonlinear function is typical for modes of excretion in the biological field. Regulation of sebum excretion is probable. Objections against such regulation by feedback were discussed.

Feedback↗
PubMed1979

[Long-term treatment of bradycardia by means of an atropine ester (SCH 1000). Electrophysiological and clinical results].

Electrophysiological effects of the atropin ester Ipatropiumbromide (SCH 1000) were investigated in 15 patients by His electrocardiography and high frequency atrial stimulation. Heart rate increased by 50% of base line heart rate, PA- and AH-intervals and sinus node recovery time decreased, the HF-interval remained unchanged. Physiological av-block by atrial stimulation occurred at significant higher stimulation frequencies with SCH 1000 than without medication. Additional 15 patients were treated for a longer follow-up period. Increase of resting heart rate averaged 15%. Equivocal effects on heart rate were found with exercise after SCH 1000. Non-cardiac side effects were found in 5 patients.

Adult↗
PubMed1979

[Preliminary experience with the catheter dilatation of coronary artery stenoses (author's transl)].

The method of percutaneous transluminal coronary angioplasty (PTCA) may in selected cases dramatically improve myocardial blood supply. Seven attempts were made between September and December 1978 at the Gollwitzer-Meier Institute of Cardiology; three dilatations were unsuccessful, two were moderately successful and two highly successful. The problems as to methodology and selection of patients submitted to this procedure are discussed.

Adult↗
PubMed1978

[Left ventricular dynamics with exercise after revascularization in advanced coronary heart disease (author's transl)].

66 patients with 2 and 3 vessel coronary heart disease were studied before and after complete successful revascularization. Hemodynamic measurements and biplane left ventricular angiograms were obtained at rest and during supine bicycle exercise.--After operation a significant overall decrease of LVEDP with exercise was seen; exercise LVEF increased in cases with left main disease and in most cases with double vessel disease and double bypass. Inconsistant response was present in 3 vessel disease. Improvement of left ventricular dynamics with exercise in advanced coronary disease after complete revascularization can be expected mainly in 2 vessel disease and left main coronary disease.

Angiocardiography↗
PubMed1978

[Effects of a new beta-blocker (CI 775) on left ventricular hemodynamics at rest and during exercise (author's transl)].

The effects of a new beta-blocking agent (CI 778) were studied in 8 patients in whom non-invasive data suggested absence of significant organic heart disease. The left ventricular hemodynamics at rest and during bicycle exercise were measured before and after intravenous administration of 0,9 mg/kg body weight. With exercise there was a significantly smaller increment of heart rate (18%) after beta-blockade. Stroke volume index at rest was significantly lower (17%) after administration of CI 775; the difference disappeared with exercise. There was an 18% decrease of the resting cardiac output after CI 775 and a 23% decrease with exercise. Significant changes at rest and with exercise indicating a negative inotropic action of CI 775 were noted for max dP/dt and peak measured velocity of circumferential fiber shortening (Vpm). The left ventricular enddiastolic pressure with exercise increased with borderline significance by 41% after CI 775. Also left ventricular stroke work index at rest and with exercise decreased moderately (n.s.), the systemic arterial resistance changed to the same extent as cardiac output decreased. Also the arterial venous oxygen difference increased after CI 775 only according to the decrease of cardiac output. The data suggest the hemodynamic properties of CI 775 are located between propranolol and practolol within the spectrum of available beta-blockers.

Adrenergic beta-Antagonists↗