Biomedical subjects

E Knapp

Publications and source records attributed to E Knapp.

At least 37 records · Page 2Linked to original sources

PubMed1989

[Quantitative computed tomographic flow measurements in aortocoronary venous bypass. I. Analysis of variance studies].

In 36 patients, 3 months after aortocoronary venous bypass (ACVB) surgery to the anterior interventricular branch of the left coronary artery, the density-time curve was assessed in the aorta and the ramus interventricularis anterior ACVB by computed tomography (CT). Mean values for area of time-density curve (1539 HU x sec.), effective width (10.9 sec.), peak CM concentration (140 HU), maximum increase of density (71 HU/sec.) and maximum decrease (53 HU/sec.) showed a significant (p greater than 0.01) difference between the results in aorta and the anterior interventricular branch ACVB for all parameters, excepting the effective width. We conclude that assessment of time density-curve parameters in the ramus interventricularis anterior ACVB is feasible; however, the results are significantly different from those obtained in the aorta. Clinical relevance of these data will be established in a second part of the study.

Adult↗

PubMed1989

[Quantitative computed tomographic flow measurements of aortocoronary venous bypass grafts. II. Correlation with angiographic measurements].

In 26 patients with 35 aortocoronary venous bypass grafts (ACVB) quantitative invasive angiographic parameters were compared with flow parameters of contrast medium, assessed by computed tomography. Out of seven different CT-parameters, the maximum decrease of concentration of contrast medium (40 +/- 5 HE/sec; mean +/- SEM) showed a correlation with the angiographic parameter of contrast medium quantitative flow rate (7.2 +/- 0.5 cm/sec) and this correlation (r = 0.536/SEE = 23.17) is significant (p less than 0.001). We conclude that for the single patient assessment of quantitative flow in ACVB by CT with a 3-second repetition rate could be performed with limited accuracy.

Angiography↗

PubMed1989

Risk factors for coronary artery disease: a study comparing hypercholesterolaemia and hypertriglyceridaemia in angiographically characterized patients.

Fifty-two male patients undergoing coronary angiography were allocated to four groups each consisting of 13 subjects: group I had normal coronary arteries and patients in groups II-IV exhibited coronary artery disease. In group II, plasma cholesterol was below 250 mg dl-1 and triglycerides below 160 mg dl-1; in group III, cholesterol was above 270 mg dl-1 and triglycerides under 160 mg dl-1; and in group IV, cholesterol was under 270 mg dl-1 and triglycerides above 180 mg dl-1. The hypertriglyceridaemic group IV had the highest coronary score. In addition, it had lowest lipoprotein lipase activity, lowest HDL-cholesterol and lowest high-density lipoproteins-2 (HDL-2) levels, suggesting that this type of hypertriglyceridaemia is caused--at least in part--by lipoprotein lipase deficiency with impaired removal of the triglyceride-rich lipoproteins and increased catabolism of HDL-2. Our findings point towards a type of hypertriglyceridaemia strongly associated with coronary artery disease which should therefore be treated accordingly.

Adult↗

PubMed1989

[Not Available].

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Disease↗

PubMed1989

[Sweet lupine (Lupinus luteus, var. Aurea/Weico and Lupinus albus, var. Multolupa) proteins. I. Extraction and filtration by Sephadex].

Samples of Lupinus luteus, var. Aurea/Weico and Lupinus albus var. Multolupa flours were analyzed. The flour proteins were extracted and fractionated by gel filtration, and the per cent pattern for both globulins and albumins was then determined. The dehulled seeds, previously analyzed for composition, were ground, defatted and consecutively extracted with distilled water (pH 5.0) and phosphate buffer (0.05 M, pH 8.5). The extracted protein content was measured by the Lowry simplified method. Globulins (pH 8.5 fraction) from both species were filtered through Sephadex G-100; besides, Lupinus albus globulins were filtered through Sephadex G-150, and absorbance of the collected fractions was measured at 280 nm. The dehulled seed (DS) of L. luteus and L. albus revealed a good protein content (58.2 and 41.0%, respectively). The protein extracted from L. luteus was constituted by 17% albumins and 58.4% globulins. In contrast, L. albus presented a higher albumin content (55.6%) than globulins (31.5%). The elution pattern for the Sephadex G-200 gel filtration showed for both lupine species analyzed a preponderant peak I corresponding in L. luteus to 55.0% and in L. albus to 84.1% of the total globulins content. From these results, it may be concluded that the dehulled seed protein content is 42.0% higher for the L. luteus sample than for the L. albus. The applied methodology indicated a predominant content of globulins above albumins in L. luteus, while in the case of L. albus, the albumin content was the highest.

Albumins↗

PubMed1989

[Sweet lupine (Lupinus luteus, var. Aurea/Weico and Lupinus albus, var. Multolupa) proteins. II. Separation by electrophoresis].

The albumins and globulins extracted from Lupinus luteus var. Aurea/Weico and Lupinus albus var. Multolupa defatted flour samples were analyzed by polyacrilamide gel electrophoresis. The purpose was to determine the percentage distribution of pattern in the electrophoretograms and the relative mobility values of protein. The L. luteus albumins densitogram showed six fractions, two of them, No. 2 and No. 4, represented 58.1% of the total. On the other hand, the globulins densitogram revealed five fractions, numbers 1, 2 and 3 representing 90.7%. The densitogram of peak I from Sephadex G-100 globulins filtration indicated two fractions similar to those number 1 and 2 of the total globulins, showing low relative mobility values (from 0.26 to 0.39). The L. albus albumins resolved in four fractions, with No. 2 being the most prevalent (54.3%). In regard to the L. albus globulins, these showed five fractions identical in distribution with those of peak I, fraction 2 appearing as the most important (48.2%). It was found that Sephadex G-100 did not perform a good separation. As to the relative mobility values of globulins, fractions 2 and 3 were the most prominent (relative mobility of 0.35 and 0.48, respectively). It may be concluded that L. luteus albumins presented more components but with lower relative mobility values than those of L. albus. As for the globulins from both lupine flour samples, the gel separated fractions were classified in two groups of components, those of high and of low relative mobility.

Albumins↗

PubMed1989

Increase in Hb-O2-affinity at moderate altitude (2000 m) in patients on maintenance hemodialysis.

Oxygen transport by erythrocytes was studied in eight patients on maintenance hemodialysis before, during and after a 2-week stay at an altitude of 2000 m. Dialysis was continued at that altitude. In all tests, blood samples were collected one or two days following hemodialysis. Pre-altitude tests: The patients exhibited anemia (hemoglobin concentration, Hb = 97.4 +/- 17 g/l). Due to an elevated red cell 2,3-diphosphoglycerate concentration (2,3-DPG) and mild metabolic acidosis, elevated standard and in vivo P50 values (pO2 at 50% oxygen saturation of hemoglobin, sO2) were measured. Altitude: Upon ascent, arterial pO2 decreased from 82 +/- 4 torr to about 60 torr, sO2 was lowered by 5%. After 2 weeks sojourn, pO2 and sO2 increased towards normal values. In contrast to healthy subjects, dialysis patients developed respiratory alkalosis (blood pH: +0.074) upon ascent. This caused a significant shift to the left of the oxygen dissociation curve (ODC), indicated by lowered in vivo P50-values (P50,vv,-2 torr). Red cell 2,3-DPG, P50,st (P50 at a blood pH = 7.4 and pCO2 = 40 torr), hemoglobin concentration and hematocrit showed a high day-to-day variability and did not change because of the altitude exposure. We interpret the increase of the oxygen affinity of hemoglobin in patients with renal anemia as beneficial, as it favors oxygen loading of hemoglobin in the lung during exposure to a hypoxic environment.

2,3-Diphosphoglycerate↗

PubMed1989

Exercise performance of hemodialysis patients during short-term and prolonged exposure to altitude.

The work capacity of patients on maintenance hemodialysis is impaired even at normal inspiratory oxygen pressure. A further restriction can be expected when these patients are exposed to hypoxia at altitude, since most of the usual compensatory mechanisms required to adjust to this environment are impaired or even missing. We tested the tolerance of hemodialysis patients to hypoxia and measured work capacity, hematological, and cardiovascular parameters at rest and during incremental bicycle ergometry during 3-hour exposure to altitudes of 2,000 m and 3,000 m, and during 2 weeks of exposure to an altitude of 2,000 m and compared these data with prealtitude values or with data evaluated in a control group, respectively. In control tests the patients reached work loads at exercise termination of about 66% of age and sex-matched healthy controls, the reduction correlated well with the degree of anemia. During short-term altitude exposure to 2,000 m peak work performance remained unchanged in comparison to prealtitude tests, whereas at 3,000 m it was reduced by about 12%. During the 2-week stay at 2,000 m peak work loads increased significantly by 17% accompanied by an increase in peak oxygen uptake (+15%), blood lactate, heart rates (+10 min-1), and systolic blood pressure (+20 mmHg), whereas the diastolic pressure was comparable to prealtitude values. In another group of hemodialysis patients studied at low altitude under similar experimental conditions none of these parameters was changed. Our data show that during acute exposure to altitudes up to 2,000 m maximal work of hemodialysis patients is not reduced, but is restricted at altitudes higher than that.(ABSTRACT TRUNCATED AT 250 WORDS)

Acclimatization↗

PubMed1988

Functional cardiac assessment before and after left ventricular anterior aneurysm repair, especially as related to work capacity.

Clinical, angiographic and hemodynamic parameters were assessed preoperatively and 12-20 weeks (mean +/- SD: 14 +/- 2) after left ventricular anterior aneurysmectomy in 31 consecutive patients. In 18 patients, associated coronary artery bypass surgery was necessary (1.4 grafts/patient). One patient with mitral valve insufficiency postoperatively required mitral valve replacement. No other complications and no deaths arose. The working capacity of the patients, as measured by bicycle exercise testing, compared a stage of exercise that the patient reached to the expected level of exercise for a normal person of the same sex, age and body surface. Expressed as percent of normals it increased from 39.3 +/- 28.9% (mean +/- SD) to 60.8 +/- 15.5% (p less than 0.001), angina-pectoris-free working capacity increased from 52.6 +/- 41.4 to 89.2 +/- 33.2 W (p less than 0.001). Left ventricular end-diastolic volume was determined by simultaneous biplane angiography and decreased from 277.1 +/- 84.7 to 191.0 +/- 49.1 ml (p less than 0.001). Ejection fraction increased from 35.4 +/- 12.4 to 41.0 +/- 9.6% (p less than 0.05). Left ventricular end-diastolic pressure after angiography decreased from 24.6 +/- 9.2 to 21.1 +/- 11.3 mm Hg (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1988

[Plasma catecholamine level in diagnostic heart catheterization studies].

Plasma catecholamine levels were obtained during diagnostic heart catheterization from pulmonary artery and aorta before and after injection of contrast medium in 31 patients with coronary heart disease and in 18 normals. The most striking difference between both groups is a significant decline of norepinephrine concentration in aortas after injection of contrast medium in the normals (from 296 +/- 24 [mean +/- SEM] to 225 +/- 21 pg/ml [p less than 0.01]) and no change in patients with coronary heart disease. The cause seems to be rather increased elimination than a decrease of secretion of norepinephrine. Adrenalin shows only partially similar results. Further studies will have to show, what could be the reason for these different reactions of catecholamine level in normals and in patients with coronary heart disease.

Adult↗

PubMed1988

[Decrease in left ventricular stroke performance following bypass of a significant main coronary artery stenoses].

Hemodynamic parameters and left ventricular function were assessed 14 +/- 4 (means +/- SEM) days preoperatively and 101 +/- 5 days after aortocoronary bypass surgery in eight men (51-65 years of age) with left main coronary stenosis (greater than or equal to 75%). Working capacity on bicycle exercise stress test increased from 43 +/- 7 to 68 +/- 7% of age-, and body-surface matched normals; at the same time cardiac output (thermodilution) decreased from 5.7 +/- 0.5 to 4.7 +/- 2 l/min (p less than 0.05), stroke volume decreased from 78 +/- 6 to 63 +/- 3 ml (p less than 0.01), stroke work from 1.16 +/- 0.10 to 0.89 +/- 0.07 Joule (p less than 0.001), and stroke power from 4.0 +/- 0.3 to 3.4 +/- 0.2 Joule/s (p less than 0.01) postoperatively. Left ventricular volumes decreased postoperatively but not significantly, ejection fraction remained unchanged (57 +/- 13/59 +/- 13%). A control group (PTCA of LAD) showed no significant changes of these parameters. As all patients had a good postoperative result, decrease of stroke work after aortocoronary bypass surgery is not necessarily an expression of postoperative deterioration, since it can coincide with good left ventricular function, angiographically successful revascularization, and an increase in working capacity.

Adult↗

PubMed1988

[Clinical, hemodynamic and morphologic findings in dilated cardiomyopathy].

45 patients (39 men, six women), mean 41 (19-63) years of age with clinical, angiographic and morphologic diagnosis of dilated cardiomyopathy were evaluated in respect of three morphologic classes. Two groups of patients without signs of previous myocarditis were formed, with one-to-two mitochondria per two sarcomeres (group Ia, n = 19), or with more than two mitochondria per two sarcomeres, respectively (group Ib, n = 14); and one group with signs of previous myocarditis (group II, n = 12). The mean relative mitochondrial volume fraction in relation to myofibril volume fraction was significantly lower in group Ia (33 +/- 4/67 +/- 4%) compared to group Ib (39 +/- 5/61 +/- 5%) (p less than 0.01). Mean values of group II (36 +/- 6/64 +/- 6%) were in between the two other groups. Left ventricular enddiastolic pressure (18 +/- 11, 18 +/- 8, 16 +/- 10 mm Hg), pulmonary vascular resistance (473 +/- 414, 406 +/- 205, 458 +/- 495 dyn x s x cm-5), ejection fraction (36 +/- 21, 32 +/- 16, 28 +/- 16%), endsystolic volume index (131 +/- 82, 127 +/- 66, 132 +/- 60 ml/m2), enddiastolic volume index (187 +/- 81, 176 +/- 62, 181 +/- 63 ml/m2), dp/dt max (1951 +/- 875, 1737 +/- 575, 1741 +/- 478 mmHg x s-1) and mean VCF (0.76 +/- 0.58, 0.44 +/- 0.32, 0.54 +/- 0.39 s-1) showed no significant differences between the three groups. Follow-up of the patients in the three groups to median 19, 22, 24 months, respectively, after biopsy, showed an improvement of the clinical findings, especially concerning the groups with one-to-two mitochondria only and with signs of previous myocarditis, but no difference in survival within the three groups. For the individual case our morphologic parameters seem to be without predictive value.

Adult↗

PubMed1987

[Cardiokymography: relative quantification of results in normal probands].

The main problem with cardiokymography (CKG) and the principal reason for its limited clinical application to date is the deficiency of calibration and quantification of results. We tried to improve the value of the procedure by quantification of the results in 14 healthy young men (age: 23, 18-31 years) in place of subjective assessment. Before and after a bicycle exercise stress test CKG tracings were obtained in a lying position at rest, immediately after exercise and after recovery. Two different methods were applied to quantify the CKG tracings (distance method and area method). The relative height of the curves at rest was 89 +/- 72% (68 +/- 39%), immediately after exercise 111 +/- 60% (73 +/- 27%) and, after recovery 121 +/- 88% (78 +/- 49%). The relative change in the height of the curves between rest and exercise was not significant according to both methods (+22 +/- 64%/+5 +/- 32%), but the variation of values in an individual patient between rest and exercise was large. Interobserver variability was rather large, according to two independent investigators. Hence, it was not possible to establish limits of normal values in quantitative CKG, but only mean values.

Adult↗

PubMed1987

Sudden death in a young competitive athlete with Wolff-Parkinson-White syndrome.

The case history is documented of a young competitive athlete known to have the electrocardiographic pattern of the Wolff-Parkinson-White syndrome, but considered asymptomatic. On that basis competitive sport was not proscribed. In retrospect, he had experienced occasional tachycardias which were of short duration and ended spontaneously. He never requested medical advice. The boy was first admitted for an attack of rapid heart beating which did not readily subside. He was medicated with prajmalium and left the hospital in stable condition. He died suddenly 10 days after discharge. Autopsy examination of the heart revealed an accessory atrioventricular connection in the posterior septal region. The case history underlines that in some patients with the Wolff-Parkinson-White syndrome the clinical manifestation can be minimal and may be easily ignored by the patient. In retrospect, benign episodes of rapid heart beating most likely were due to a circus movement tachycardia, related to an accessory atrioventricular connection. The sudden death can be attributed to atrial fibrillation with rapid ventricular response via the anomalous connection, despite medical treatment. The observation endorses the potential danger of the Wolff-Parkinson-White syndrome in patients with minimal clinical manifestations. A meticulous histologic study of the atrioventricular junction in hearts of young athletes with sudden and unexplained death is a necessity.

Adolescent↗

PubMed1987

[Comparison of methods for the relative quantification of the hump in cardiokymographic tracings].

Exercise stress testing in a sitting position was carried out preoperatively and three months post aortocoronary bypass surgery in 125 men. Before exercise, immediately after exercise and after 5 minutes of recovery cardiokymography (CKG) was performed in a lying position. So called "bulges" in the CGK-tracings, defined as Type I, II or III registration by non quantitative judgement so far, were set out quantitatively by evaluation of area (Flächen-method) or distance (Distanzmethod) of the bulge. We found a significant increase (p less than 0.001) of bulges according to both methods after exercise but no difference between rest and after recovery concerning the area method. The distance method showed higher values (p less than 0.05) after recovery than at rest. All mean values postoperatively were not significantly lower than the corresponding values preoperatively. Our results show, that CKG-tracings can be quantitatively assessed both by the area or by the distance method. The latter is easier to apply and has comparable results to the area method.

Adult↗

PubMed1986

[Complications and results following transseptal or retrograde transaortic catheterization of the left ventricle in patients with aortic valve stenosis].

Retrograde transvalvular left heart catheterization was successful in 46 cases out of 71 consecutive patients with severe valvular aortic stenosis. In 16 patients the transseptal route was used and in the remaining 9 patients surgery was performed without left ventricle pressure recordings. There were no differences in aortic valve area or in pressure gradients in pure stenosis (n = 29) whether retrograde catheterization succeeded or not. In combined aortic valve disease with prevalence of stenosis (n = 42) transaortic catheterization succeeded less frequently in patients with higher pressure gradients. The complication rate increased with duration of catheterization, but without adverse consequences for any patient.

Adult↗

PubMed1986

[Late complications following Björk-Shiley and Carpentier-Edwards heart valve replacements].

Valve related and valve induced, fatal or non fatal complications after Björk-Shiley valve replacement (n = 50) are compared with complications following Carpentier-Edwards valve replacement (n = 113). These patients had been operated upon between 1976 and 1982 and were followed up until 1985. Estimated actuarial cumulative survival following Carpentier-Edwards valve replacement (53 +/- 12% after a 100-month period) did not differ significantly from the estimate following Björk-Shiley valve replacement (80 +/- 6% after a 100-month-period), and subgroups of the cohort did not differ in survival after Carpentier-Edwards or Björk-Shiley valve replacement either. However, the estimate of actuarial cumulative event-free survival following Carpentier-Edwards valve replacement in patients under 40 years of age (46 +/- 14% after a 92-month period) was significantly worse (p less than 0.05) than with Björk-Shiley valves (100 +/- 0% after a 92-month period), (n = 30). The leading cause of clinical complications following Carpentier-Edwards valve replacement was a demonstrable degeneration of the bioprosthesis in 12 cases. The diagnosis of degeneration was established a mean of 73 months postoperatively (range 42-101 months).

Adult↗

PubMed1985

[Surgical therapy of coronary disease: aortocoronary bypass. Risks and complications].

The aorto-coronary bypass surgery is a well established method for treating patients with coronary artery disease. In the last five years at the University Clinic in Innsbruck 417 operations have been performed. The operation letality decreased down to 0.66%, whereby the mean revascularisation rate increased to 2.8. The specific aim of this paper is to show the benefits and the risks of this operation to validate and to verify the benefits in regard to the risks, which could be kept very low.

Adult↗