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Biomedical subjects

A Heitz

Publications and source records attributed to A Heitz.

71 records · Page 4Linked to original sources
PubMed1980

Blood pyruvate recovery curves after short heavy submaximal exercise in man.

Arterial pyruvate and lactate concentrations were measured after short heavy submaximal exercise on a bicycle ergometer, at 10 or 30 s time intervals, on six male subjects. During most of the first 2 min of recovery pyruvate concentration decreased. Thereafter, it increased and reached its maximum within the 5th to 9th min of recovery. Finally, it decreased gradually as a function of time. Recovery curves could be accurately described after a short delay time following the end of the exercise, by a sum of three exponential terms according to the equation: (Formula: see text), where the time origin (to) is fixed at about 1-1.5 min(delay time) after the end of exercise, t is the time after to, Y(O) and Y(t) are the concentrations of pyruvate respectively at times zero and T, and Ai and zi are constants. The velocity constant of the final arterial blood pyruvate decrease was similar to that of the simultaneously measured lactate, indicating that the rate of lactate removal is closely related to that of pyruvate. This is consistent with the fact that pyruvate is a necessary intermediate in the lactate metabolism.

Adult↗
PubMed1980

[Aortic and mitral monovalvular replacements. Comparison of the ball prosthesis of Starr-Edwards (1260-6120) and the tilting disc prosthesis of Bjork-Shiley. Series of 390 patients].

The evaluation of short and long term replacement by the Björk-Shiley tilting disc prosthesis (BS) and by the Starr-Edwards ball and cage prosthesis (SE) was carried out on a series of 390 consecutive patients. In mitral replacement, operative mortality rate (SE 5.9 P. 100 - BS 4.8 P. 100), 5 year actuarial survival (SE 79.8 P. 100 +/- 3.8 P. 100 - BS 86.3 P. 100 +/- 9 p. 100) incidence of thromboembolic complications and valvular thrombosis (SE 1.6 P. 100 - BS 1.3 P. 100) as well as the degree of post-operative improvement were virtually identical in both types of prosthesis. Likewise, in aortic valve replacement, operative mortality rate (SE 4 p. 100 - BS 3.2 p. 100), 5 year survival (SE 82 +/- 7.8 P. 100 - BS 86 +/- 3.3 p. 100) incidence of thromboembolic complications (SE 2.2 p. 100 - BS 1.8 p. 100) and the degree of post-operative improvement were not statistically different. However, the incidence of sudden death was statistically smaller with a BS prosthesis than with a SE prosthesis (respectively 1.6 p. 100 and 6.9 p. 100).

Actuarial Analysis↗
PubMed1979

[Real-time cross-sectional echocardiography. Application in the measurement of the surface area of the mitral orifice in cases of stenosis or of double involvement of the valve (author's transl)].

Two-dimensional echocardiography in real time has proved in recent years to be a very valuable means of investigation in cardiology, in particular in the area of valve disease and congenital cardiac malformations. The present study concerns a group of 20 patients with essentially stenosing mitral disease, studied by two-dimensional echocardiography using mechanical sector scanner. The authors report their experience of the method in the measurement of the surface area of the mitral orifice from echotomographic sections obtained in protodiastole in a plane perpendicular to the long axis of the left ventricle and passing through the free edge of the mitral cusps. Fifteen of these patients being then treated by valve replacement, the area measured were compared with those found in the operative specimens. In 14 cases out of 15 (93%), despite the concomitant existence of appreciable mitral incompetence in 9 cases out of 15, the surface areas did not differ by more than 0.23 cm2 (coefficient of correlation = 0.990). These results confirmed that two-dimensional echocardiography in real time is a reliable method for the direct measurement of the mitral orifice area in the presence of stenotic type disease of the valve and even in the presence of associated mitral regurgitation.

Adult↗
PubMed1979

Clinical and angiographic determinants of early mortality related to aortocoronary bypass surgery.

Clinical and angiographic features were identified that influences early mortality in 807 patients who underwent aortocoronary bypass grafting alone among the first 1000 consecutive patients subjected to aortocoronary bypass operations at the Montreal Heart Institute. The early mortality was 4.7% and was related to the patient's age, the duration of the illness from its first clinical manifestation, certain types of clinical presentation, electrocardiographic findings, the number of obstructed arteries and the ejection fraction. The influence of the number of obstructed arteries appeared to be independent of other factors, including the number of grafts and the degree of correction. Early mortality was not influenced by risk factors such as lipid abnormalities, hypertension or diabetes, by the history of previous myocardial infarction or the number of grafts.

Adult↗
PubMed1979

[Problems encountered by the anesthetist-intensive care specialist during aorto-coronary bypass surgery].

The authors studied a series of 288 patients undergoing surgery for aorto-coronary bypass. The anaesthetic protocol and operative protocol are described and particular emphasis is placed upon the aortic clamp time. Mortality and peri-operative complications are then analysed. The treatment of such complications is based essentially upon vasodilators and where necessary intra-aortic counter-pressure balloon device to provide circulatory assistance.

Anesthesia↗
PubMed1978

[Surgical treatment of massive pulmonary embolism. (Reported of 45 successful embolectomies inclusive 10 with Trendelenburg's technic) (author's transl)].

45 pulmonary embolectomies have been carried out successfully, 10 by Trendelenburg's procedure, 35 with extracorporeal circulation. The latter method gives satisfactory results (34 survivals out of 36 attempts since 1970) and appears to be the procedure of choice. Any pulmonary trauma should be avoided at operation; embolectomy is done by intra-vascular suction. The hemodynamic status was always abnormal: 5 initial cardiac arrests, 20 cases of severe shock (9 demonstrating cardiac arrest on the operating table) and 11 cases with less severe shock. In 9 cases cyanosis, respiratory distress and signs of acute cor pulmonale were the clinical features of the massive embolus. In 9 patients the operation was performed after an unsuccessful trial of thrombolysis. Preoperative pulmonary angiography could be performed in 30 cases and always showed extensive pulmonary vascular obstruction of 60 to 95 per cent. These data are important for diagnosis and for assessment of the prognosis. Despite of present medical treatment with fibrinolytics, surgery is still advisable in the treatment of massive pulmonary embolism. The indications are moribund patients, those in whom thrombolysis is contraindicated or unsuccessful and those with massive pulmonary obstruction (greater than 60 per cent). In this latter subset thrombolytic therapy carries a high level of mortality.

Clot Retraction↗
PubMed1977

Influence of left ventricular function and other parameters on early and late mortality following coronary bypass surgery.

Left ventricular performance, coronary anatomy and postoperative clinical parameters of 66 control patients (group 1) randomly selected from 797 survivors of coronary bypass surgery were compared with those of 45 patients who died within 30 days of operation (group II) and 53 patients who died late (average, 22+/-2 mo) (group III). Average preoperative left ventricular end-diastolic pressure, ejection fraction and mean circumferential fibre shortening rate were significantly better in group I than in group III patients. These same parameters were not significantly different when group I was compared to group II. Abnormal wall motion was significantly less frequent in patients from group I than in patients from group II and III. Triple-vessel disease was present preoperatively in 40 (61%) controls compared with 37 (82%) early deaths (P = 0.021) and 35 (66%) late deaths (NS). The number of grafts placed per patient was not significantly different in the three groups. Perioperative myocardial in farction (MI) and low cardiac output syndrome were the commonest causes of early death. Late complications such as MI and heart failure occurred in 4 (6%) v; 15 (32%) (P = 0.0006) and 4 (6%) v. 27 (57%) (Pless than 0.0001) group I v. group III patients, respectively. Surgical expertise, preoperative ventricular performance and triple-vessel disease are important determinants of early mortality following bypass surgery and preoperative left ventricular performance is one of the most important determinants of late mortality,

Coronary Artery Bypass↗
PubMedDate not supplied

Molecular recognition between serine proteases and new bioactive microproteins with a knotted structure.

Microproteins with proteinase inhibitory activity, 28 to 30 amino acids long, with 3 disulfide bridges have been isolated from Ecballium elaterium seeds. A peptide (EETI II) was isolated and behaved as a powerful trypsin inhibitor (Kd = 10(-11) to 10(-12) M). It was sequenced, chemically synthesized and the 3-D structure determined by 2-D 1H NMR. The information gained in the process enabled us to synthesize modified derivatives with inhibitory activity towards pancreatic elastase, chymotrypsin and human leucocyte elastase (Kd = 10(-7) to 10(-9) respectively). The most striking characteristic that appeared during the synthetic approach was the unfailing ability of the 28 amino acid peptides to refold and correctly close the 3 disulfide bridges, giving in each case an active compound. These disulfide bridges are assembled in a particular knotted structure, shared by few other bioactive peptides and called the 'knottin' structure. Molecular modeling of the peptide and a comparison with the other active molecules with similar topology allowed the synthesis of a chimaeric peptide, bearing 1 active site against a seryl-protease (trypsin), and 1 against a metallo-protease (carboxypeptidase A). The bis-headed peptide was able to inhibit both enzymes separately and concomitantly.

Amino Acid Sequence↗