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Biomedical subjects

P Schweizer

Publications and source records attributed to P Schweizer.

At least 73 records · Page 4Linked to original sources
PubMed1988

Time-space distribution of extrahepatic biliary atresia in The Netherlands and West Germany.

Extrahepatic biliary atresia (EHBA) is an infrequent disease confined to early infancy. Its aetiology is not clear, but an infectious agent has been implicated. Demonstration of a time-space clustering would support this hypothesis. Therefore, we investigated the time-space distribution of all 89 cases of EHBA born in a 10-year period in the Netherlands. We carried out a similar study in West Germany and analysed 130 cases of EHBA, born between 1969 and 1986, from 4 paediatric surgical centres. Analysis of these cases did not reveal any evidence for clustering in specific years or in a specific period of the year. The places of birth of the patients also were randomly distributed over rural areas, villages and towns. Neither did a method to reveal time-space interaction give any support for clustering. This random distribution of patients with EHBA suggests that EHBA could be pathogenetically a heterogeneous disease.

Biliary Atresia↗
PubMed1988

Efficacy of hepatobiliary scintigraphy in the differential diagnosis of neonatal cholestasis and postoperative follow-up after hepatoporto-digestive anastomosis.

In the differential diagnosis of unclear neonatal and infant cholestasis the formerly applied 131-I-Rose Bengal scintigraphy has been widely abandoned in favour of hepatobiliary scintigraphy with 99mTc-labelled IDA derivatives excreted with the bile. Our results in 32 jaundiced children ranging from ages 2 weeks to 32 weeks show a high sensitivity of scintigraphy in proving an occlusion in 92% with a clearly lower specificity of 79%, if based on the demonstration of marked bile in the intestine as the only criterion. Diagnostic accuracy, however, can be further increased in additional criteria such as hepatocellular clearance and patient age are considered. The examination is of equally high importance for post-operative follow-up. Here, scintigraphy is superior to all other imaging procedures in the evaluation of bile flow situations. In 52 examinations of portoenterostomies, the prognostic value can be demonstrated not only with a good coincidence of the scintigraphic data with the bilirubin level, but also with the histological degree of liver fibrosis at the time of operation. Early and late complications of hepatoportojejunostomy can usually be recognised and localised. Since the prognosis of extrahepatic biliary atresia depends on an early operation-presently by means of reconstruction of biliary flow-indications for hepatobiliary scintigraphy must be given more widely and earlier (at the latest in the fourth week of life) in all unclear cases of cholestatic syndrome.

Anastomosis, Surgical↗
PubMed1988

[Accomplishments of tumor surgery in soft tissue sarcoma in childhood].

Malignant soft tissue tumors, a group of neoplasms with various biological characteristics, have been of oncologic interest only for the last 20 years. More than half of all soft tissue sarcomas are Rhabdomyosarcomas (RMS). Extensive comparative therapy studies have yielded both improved results and a lot of biological data on RMS and other malignant soft tissue tumors. The results of CWS 81/86 are analysed and a therapy protocol is proposed.

Child↗
PubMed1986

Detection of spontaneous echocardiographic contrast within the left atrium by transesophageal echocardiography: spontaneous echocardiographic contrast.

Transesophageal echocardiography was performed in 314 patients over a period of 24 months using a 3.5 MHz phased-array system fitted to the distal end of a conventional 12 mm endoscope. In 12 patients (2.6%) transesophageal echocardiography could not be performed because of adverse reaction to the gastroscopic procedure. Side effects were a transient A-V block in one patient and asthmatic attack in another. Mitral valve lesions were found in 99 of 314 patients. In 9 of these 99 patients (11%), including 1 patient with mitral valve stenosis and sinus rhythm, 2 with atrial fibrillation, 3 with disc, and 3 with porcine mitral prosthesis, spontaneous echocardiographic contrast was found within the left atrium, described as faint echoes in 2 patients and dense echoes filling the whole left atrium and following turbulent flow in the other 7 patients. Only in 2 patients was left atrium shown to have additional echoes within its cavity in the four-chamber view by transthoracic echocardiography. Signs of cerebral emboli were found in 5 of 9 patients and of peripheral embolism in 3 of 9 patients. Their mechanism seems to involve red cell aggregation, which is greatest at low flow velocity such as in dilated left atria in the case of mitral valve stenosis or prosthesis. The additional effect of platelet aggregation must be discussed because increased platelet aggregation was detected in all patients with spontaneous echocardiographic contrast. Transesophageal echocardiography seems to be of great diagnostic value in patients with mitral valve lesions and cerebral and peripheral embolism, giving new insight into the pathophysiologic mechanism and possibly improving the therapeutic approach in the near future.

Adult↗
PubMed1986

Right ventricular volume determination in isolated human hearts.

For right ventricular volume determination a new method was developed that took into account right ventricular imaging by apical two-dimensional echocardiography in the four- and two-chamber views. Right ventricular volume was calculated by subtraction of the partial volume of the left ventricle and interventricular septum from the total heart volume of the right and left ventricles including the interventricular septum. Accuracy of the subtraction method was evaluated in isolated human hearts by two-dimensional echocardiography and radiography. Regression analysis indicated that for both the echocardiographic and radiologic procedures, the subtraction method gave the best correlation with the right ventricular filling volume. The correlation coefficients obtained using the echocardiographic procedure were 0.964, 0.848, and 0.851 for the subtraction method, pyramid method, and Simpson's rule method, respectively. For the radiographic procedure, these values were 0.946, 0.860, and 0.872. Percentage difference calculations indicated that the subtraction method systematically underestimated (-7.4%) the filling volume in the echocardiographic procedure, but this was not seen with the radiologic procedures. The random error associated with the subtraction method was only half (10.5%, 13.9%) of that seen with the other two methods in both the echocardiographic and radiological procedures. These results indicate that right ventricular volume determination by the subtraction method seems to be suitable for apical two-dimensional echocardiography and is more accurate than the pyramid method and Simpson's rule method.

Echocardiography↗
PubMed1985

[Intracoronary streptokinase in acute myocardial infarct. Experience with 461 patients].

Between March 1980 and July 1984, coronary angiography was performed on 461 consecutive patients (no age limit) with acute myocardial infarction, and the partially or completely obstructing thrombus lysed by selective intracoronary infusion of streptokinase. At the time of first coronary angiography 96 patients (21%) had a high degree of stenosis but no total occlusion of the infarct vessel (group A). In 365 patients (79%) there was complete occlusion which in 315 patients (86%) was removed successfully after an occlusion period of 213 +/- 87 minutes (group B). In 50 patients (14%) (group C) attempts at reperfusion failed. In 129 of 163 patients (79.1%) with one-vessel disease, PTCA (percutaneous transluminal coronary angioplasty) was successful. Patients with multiple-vessel disease and an occlusion time of less than four hours, on the other hand, were treated surgically within the first ten days (78 patients). In the remaining 254 patients conservative treatment was practised. Within the first 30 days there were seven deaths (14%) in group C, while among group A and B patients, under conservative treatment, 16 died (7.8%). After successful PTCA four patients (3.1%) died. The lowest mortality was among patients with a short occlusion time and early bypass operation (2.6%). The most frequent cause of death was cardiogenic shock (20 of 29 patients), more rarely ventricular fibrillation (3) or other causes (4). Ventricular rupture occurred in three patients, one of whom was saved by pericardial tap. One year later the mortality among the conservative group was 21.2%, after successful PTCA or bypass operation 9.3% and 6.4%, respectively.

Aged↗
PubMed1985

Sensitivity of cross-sectional echocardiography in detection of impaired global and regional left ventricular function: prospective study.

In order to establish the sensitivity and specificity of cross-sectional echocardiography for detection of global and regional left ventricular function a prospective study was performed in 80 patients suspected of having coronary artery disease. Twenty four hours before heart catheterization, cross-sectional echocardiograms were recorded in the apical RAO-equivalent view and high quality echocardiograms were obtained in 71/80 patients (89%). M-mode echocardiograms of the left ventricle could be performed in 56/71 patients (79%). Based on normal values sensitivity and specificity of cross-sectional echocardiography were calculated in comparison to cineventriculography. For fractional shortening (normal value greater than 25%) sensitivity measured 46% and specificity 93%, and when the E-point septal separation was measured (normal value less than 7 mm), sensitivity increased to 73% and specificity was 84%. For detection of increased end-diastolic volume (less than 155 ml) sensitivity reached 84% and specificity 98% and for increased end-systolic (less than 70 ml) volume it was 86 and 97%, respectively. A depressed left ventricular ejection fraction (greater than 49%) was found with a sensitivity of 93% and specificity of 100%. Regional left ventricular wall motion, analyzed by an area method, revealed for anterior wall motion a sensitivity of 68% and a specificity of 94%, whereas for posterior wall motion sensitivity reached 80% and specificity 96%. Regression equation between the number of pathological segments and left ventricular ejection fraction for cineventriculography was given by Y = -4.06 X + 73.4, r = 0.93 and for cross-sectional echocardiography by Y = -3.69 X + 62.6, r = 0.85. We conclude that cross-sectional echocardiography can be used as a screening method to detect impaired left ventricular function. It is superior to M-mode echocardiography. Reduced regional function of the posterior wall can be found with high sensitivity, but depressed motion of the anterior wall may be overlooked.

Adult↗
PubMed1985

[Long-term results in the treatment of extrahepatic bile duct atresia].

This article is intended as a contribution towards the question of long-term results to be expected when using hepato-portodigestive anastomoses in children. The paper is based on analyses of the course of the disease in 683 children, as placed at the author's disposal by paediatricians and paediatric surgeons in Europe, the United States of America, and Japan, as well as on an evaluation of 56 child patients observed by the author himself. This assessment resulted in the formulation of five conditions determining the prognosis. One can expect a 5-year survival rate of 66 per cent with good clinical, laboratory, sonographic and scintiscan data as well as histological findings, provided surgery is possible before 6 weeks after onset of cholestasis (this usually means surgery before the 8th week of life), provided also that cirrhosis has not set in at the time of surgery and that there are no additional numerical and morphological changes of the interlobular bile ducts; furthermore, if the average total diameter of the bile duct structures in the hepatic porta is at least 450 mu, and if no cholangitides occur postoperatively. If these conditions are not fulfilled, prognosis must be considered as poor. Such patients become candidates for a liver transplant, which has a 4-year survival rate of 58 per cent since introduction of the cyclosporin A-low-dose-steroid treatment. The article also discusses questions of organisation and of ethics connected with liver transplantation.

Bile Ducts↗
PubMed1985

Effect of Nitrate and Ammonium Nutrition of Nonnodulated Phaseolus vulgaris L. on Phosphoenolpyruvate Carboxylase and Pyruvate Kinase Activity.

Young bean plants (Phaseolus vulgaris L. var Saxa) were fed with 3.5 or 10 millimolar N in either the form of NO(3) (-) or NH(4) (+), after being grown on N-free nutrient solution for 8 days. The pH of the nutrient solutions was either 6 or 4. The cell sap pH and the extractable activities of phosphoenolpyruvate carboxylase and of pyruvate kinase from roots and primary leaves were measured over several days.The extractable activity of phosphoenolpyruvate carboxylase (based on soluble protein) from primary leaves increased with NO(3) (-) nutrition, whereas with NH(4) (+) nutrition and on N-free nutrient solution the activity remained at a low level. Phosphoenopyruvate carboxylase activity from the roots of NH(4) (+)-fed plants at pH 4 was finally somewhat higher than from the roots of plants grown on NO(3) (-) at the same pH. There was no difference in activity from the root between the N treatments when pH in the nutrient solutions was 6. The extractable activity of pyruvate kinase from roots and primary leaves seemed not to be influenced by the N nutrition of the plants.The results are discussed in relation to the physiological function of both enzymes with special regard to the postulated functions of phosphoenolpyruvate carboxylase in C3 plants as an anaplerotic enzyme and as part of a cellular pH stat.

Journal Article↗
PubMed1984

Effects of heart rate changes on left ventricular volume and ejection fraction: a 2-dimensional echocardiographic study.

The influence of heart rate on left ventricular (LV) volumes and ejection fraction (EF) using 2-dimensional (2-D) echocardiography during atrial pacing was analyzed. The study was performed in 13 normal control subjects, 23 patients with coronary heart disease and 8 patients with dilated cardiomyopathy. An electronic sector scanner (2.25 MHz, 84 degrees) was used. Under constant scanning of the left ventricle, heart rate was increased, in steps of 20 beats/min, from 80 to 140 beats/min. The 2-D echocardiograms were stored on videotape and analyzed off-line. The end-diastolic and end-systolic volumes (EDV and ESV) were determined using a disc method. Stroke volume (SV) and EF were calculated. Constant LV scanning was possible during atrial stimulation, as shown by the analysis of simultaneously recorded 2-D echocardiograms and cineventriculograms at different heart rates, revealing a constant position of the echocardiographic transducer. Simultaneous recordings of cineventriculography and 2-D echocardiography at 80 and 120 beats/min showed that despite differences in absolute values, percent changes of LV volumes and EF determined with both methods were similar. Thus, changes of LV function can be analyzed by 2-D echocardiography. In normal control subjects, an increase in heart rate of 10 beats/min reduced EDV by 4 ml, ESV by 2 ml, SV by 2 ml and EF by 1%, corresponding to percent reductions of 4, 2, 5 and -2%, respectively. In contrast, the absolute decreases in the patients were 6 ml, 1 ml, 5 ml and 2% and the percent changes 2%, 1%, 8% and 5%.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

[Peculiarities of burns in childhood].

In contrast to adults the protein and energy loss leads to hypermetabolism in the burned child. This is because their glycogen and fat reserves are limited. The catabolism finds expression in the rapid loss of weight resulting from reduction of the structure proteins. Therapeutic consequences will be discussed in this paper. Furthermore cases will be demonstrated where extensive third degree burns were able to be treated by mixed allografts and autografts.

Burns↗
PubMed1984

Sensitivity and specificity of two-dimensional echocardiography in detection of impaired left ventricular function.

The purpose of the study was to determine the sensitivity and specificity of two-dimensional echocardiography (2dE) in the detection of impaired left ventricular function, compared with cineventriculography (CVG). Apical two-dimensional echocardiograms were performed in 110 patients undergoing heart catheterization for the evaluation of clinically suspected coronary heart disease (50 patients), valvular heart disease (38 patients) and congestive cardiomyopathy (22 patients). The left ventricle was scanned in the RAO-equivalent view; cineventriculograms were filmed in the 30 degrees RAO projection. Left ventricular volumes at end-diastole (EDV) and end-systole (ESV) were determined using a disc method; stroke volume (SV) and ejection fraction (EF) were calculated. Based on normal values, the sensitivity, specificity, and predictive accuracy were determined for two-dimensional echocardiography. For EDV, the sensitivity was 80%, specificity 88% and (+) predictive accuracy 86%. The left ventricular ejection fraction was 57.8 +/- 17.2% with CVG and 53.8 +/- 15.6% with 2dE in patients with coronary heart disease, 24.9 +/- 10.5% with CVG and 25.2 +/- 11.1% with 2dE in patients with congestive cardiomyopathy, and 61.1 +/- 13.9% with CVG and 54.2 +/- 9.1% with 2dE in patients with valvular heart disease. Sensitivity was 81%, specificity 100%, and (+) predictive accuracy 100%. The study demonstrates that impaired left ventricular function can be detected by 2dE with high sensitivity and specificity. Thus, 2dE seems to be suitable screening method for evaluation of left ventricular function.

Adult↗
PubMed1984

[Echocardiographic monitoring of acute myocardial infarct following intracoronary streptolysis treatment].

Two-dimensional echocardiography is helpful in the detection of wall motion abnormalities and in the evaluation of time courses of regional function due to interventions. Of 301 patients with acute myocardial infarction treated with selective intracoronary infusion of streptokinase, 229 (76%) revealed a totally occluded infarct related vessel at the first angiography. In 64 patients a two-dimensional apical long-axis view of good technical quality could be obtained after admission, on the 1st, 2nd and 3rd day and again in the 4th to 6th week and the 9th to 14th month after the acute intervention. The collective was divided into two subgroups according to the different time interval between the beginning of symptoms of infarction and the reopening of the occluded vessel. 35 patients had a total time of occlusion of less than 4 hours (group A), while in 29 others this time exceeded 4 hours or thrombolysis was unsuccessful (group B). Using a computer system, the center of gravity of the end-systolic frame of the left ventricle was used as an inner fix point. 10 end-systolic and end-diastolic area segments were constructed. Regional wall motion was determined as a percentual change of the enclosed area, normalized to the end-diastolic area (% delta F). The ejection fraction was calculated using a disc method. In group A the ejection fraction increased from initially 46 +/- 9% to 51 +/- 8%, 52 +/- 8% (p less than 0.05) and 53 +/- 8% (p less than 0.01) on the 1st, 2nd and 3rd day, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac Output↗
PubMed1983

[Emergency diagnosis of acute aortic insufficiency using one- and two-dimensional echocardiography].

Acute aortic valve insufficiency generally leads to an emergency situation followed by surgery. Using echocardiography pathological findings of the aortic valve or the ascending aorta leading to acute aortic insufficiency could be differentiated exactly and rapidly in 12 out of 13 cases. Dissecting aneurysms of the aorta and bacterial endocarditis were the most frequent causes (50 and 43%). Our results showed clear-cut superiority of combined use of one- and two-dimensional echocardiography to M-mode techniques. Both methods complement each other with their advantages and disadvantages. With their help recognition of causes of aortic insufficiency is possible more rapidly, safer and with a higher sensitivity than with the M-mode method alone. Invasive diagnostics may thus become unnecessary in the appropriate cases.

Adult↗
PubMed1983

[2-dimensional echocardiography in acquired heart valve defects].

A fundamental improvement in the diagnosis of acquired valvular defects has been achieved by the introduction of two-dimensional echocardiography. For the first time, it has now become possible to visualize the underlying morphological changes direct and true to anatomy. Additional information is supplied by a detailed study of the dynamics of the affected valve. At present, limited information only can be obtained in respect of the haemodynamic severity of the defect. In the near future, however, we may expect advances also in quantitative respect, from a combination of this method with Doppler echocardiography or contrast echocardiography.

Aortic Valve Insufficiency↗