Biomedical subjects
Publications and source records attributed to P Schweizer.
Two weeks after hysterectomy, circulatory collapse with hypotension and tachycardia occurred in a 40-year-old woman. M-mode and 2-D echocardiography confirmed the clinical diagnosis of acute pulmonary arterial embolism.
Following carotid sinus stimulation a hyperactive reflex with ventricular asystole of more than 3 seconds was found in 9 out of 40 asymptomatic patients aged more than 60 years. Results varied considerably between different investigators and different investigation days. Over a period of two years patients with hyperactive reflex did not have a worse prognosis than patients with normal reflex response. Symptoms indicating hypersensitive carotid sinus syndrome had not been observed in a single case. The frequent occurrence of hyperactive carotid sinus reflex and its favourable prognosis and the similarly frequent occurrence of vertiginous attacks due to numerous reasons, in the older age group, do not readily allow for a diagnosis of the hypersensitive carotis sinus syndrome, even when both symptoms occur at the same time. Pacemaker implantation should only be considered when repeated syncope has occurred which cannot be attributed to other causes despite extensive investigations.
The excision repair deficient mei-9L1-embryos of Drosophila melanogaster are up to four times more radiosensitive than normal +/+ embryos. The lack of oxygen-effect in the repair deficient 4-h-embryos and the reduced O2-effect in the 13/4-h embryos suggest an interpretation of the oxygen effect as a modification of the ability to repair. The conversion of the early death (heavy damage) to late death (slight damage) by irradiation of normal embryos in N2 supports this interpretation. This theory can also explain the dependence of O2-effect on LET. The spontaneous lethality and the increase in radiosensitivity depend in heterozygous mei-9L1-embryos strictly upon the genotype of the mother, thus representing a maternal effect.
32 cases of sympathetic nervous system tumours have been treated in a single pediatric oncologic center during 1970-79 and have been submitted to a follow-up analysis according to the known prognostic parameters. A high significance of prognostic staging is seen in correlation to age, stage, site of the primary, histologic differentiation, postoperative excretion of metabolic catecholamines and surgical radicality. The overall lethality in this material has been 38%, in contrast to a lethality rate of 72% in the same center during the preceding period (1960-69). The reason for this notable drop is thought to be early diagnosis leading to a combination of favourable prognostic parameters. Total surgical removal of the primary is considered the most important therapeutic factor, being exclusively sufficient in cases where the prognosis is favourable (first year of life, stage I and II). A long term lethality rate subsequent to cytotoxic treatment has been observed, so that the 2-years-survival time has to be discussed.
The clinical courses in 39 children with NEC were studied to answer questions about pathogeny and the indication for surgical treatment. Anamnestic, clinical and hematological findings show an ischemia to be the "conditio sine qua non". Disseminated intravascular coagulation does not seem to be the primary cause of the disease. Whether bacterial infections of the intestinal wall are of importance in the pathogeny cannot sufficiently be proven on the available findings. The clinical symptoms, the number of platelets and the level of serum-sodium make it possible to classify NEC in four stages with typical morphologic appearance. The results of an early and of a late treatment by operation are compared and it is deduced that the best moment for surgical intervention will be the change from stage II to stage III. Symptoms of stages II/III are the progressive clinical course with increasing intestinal bleeding, edema of the abdominal wall and scrotum, thrombopenia and low sodium level.
Between 1970 and 1980 53 children with epiphyseal injuries were treated. Analysing these 53 cases we found that metaphyseal lesions of the epiphyseal plate (i.e. epiphyseolysis, separation of the epiphysis with triangular metaphyseal fragment) heal completely, even in those cases in whom an open reduction was necessary. Conservatively treated epiphyseal injuries (i.e. fracture of the epiphysis, crushing of the epiphyseal plate) showed bad results. Contrary to these results 80% of open reduced injuries showed good results. We can conclude that epiphyseal injuries do not necessarily end in disturbances of growth or malformation if surgical correction of the injury is done as early as possible and if the injured extremity is immobilised at least 3 to 5 weeks. Destruction of the epiphyseal vascular system can only be avoided by surgical reposition of the epiphyseal injury.
The features of malrotation of the intestine, include the incomplete fixation of the mesentery which may lead to torsion in association with abnormal positioning of the cranial mesenteric vessels. There are also abnormal strangulated peritoneal bands extending from the large bowel across the duodenum. These anomalies can either lead to duodenal obstruction or to volvulus. The operative procedure described by Ladd has the advantage that it is brief but requires relatively frequent repeat laparotomies. Complete correction with the attempted construction of normal anatomy has the disadvantage that it is a difficult and time-consuming procedure, but the incidence of repeat laparotomy is significantly lower. It is therefore suggested that "at risk" children may be preferably treated by the Ladd procedure and this should always be used if there are anaesthetic problems.
16 cases of mesenteric caval anastomosis in children with recurrent bleeding from oesophageal varices are presented. Advantages of this technique include the quick normalisation of portal pressure and the low incidence of thrombosis or recurrent bleeding. This complication arises in 10% of patients treated with a central mesenteric caval shunt. The disadvantage of the technique presented is the reduction of perfusion of the liver and the necessity of ligating the iliac veins. An alternative procedure is spleno-renal shunt but this also leads to a reduction of liver perfusion. An alternative procedure is spleno-renal shunt but this also leads to a reduction of liver perfusion. The incidence of thrombosis and recurrent bleeding is higher using this method and on the whole the choice of technique is determined by the age of the patient.
A group of 111 patients with mitral valve disease was studied by M-mode and two-dimensional echocardiography. Five left atrial thrombi were demonstrated, two of which had probably been the source of previous embolic events. Two-dimensional echocardiography was superior to M-mode in providing spatial orientation. Using multiple cross-sections the exact localisation and the size of the thrombus formation could be estimated. Thrombus localisations at the upper, lateral, and septal atrial walls, normally inaccessible to the single-beam technique, were successfully imaged. Even two-dimensional echocardiography, however, constitutes an imperfect method. By comparison with the findings at surgery only one-third of confirmed thrombi could be detected non-invasively. According to their localisation seven clots in the appendage were missed by the ultrasound method. One further thrombus fixed to the upper left atrial wall near the entrance of the upper pulmonary veins was also undetected by echocardiography. Despite these limitations, the information provided by echocardiography can be most helpful in patient management. M-mode, in combination with two-dimensional echocardiography, is therefore recommended in all patients with mitral stenosis before diagnostic or therapeutic procedures are undertaken.
A 69-year-old man developed a rupture of the papillary muscle on the fifth day of acute posterior myocardial infarction. The two-dimensional echocardiographic features of ruptured papillary muscle included (1) mobile mass of echos attached to normal chordae tendineae in the left ventricle, (2) absent tip of papillary muscle, and (3) mitral valve prolapse. Noninvasive, two-dimensional echocardiography can reveal correct diagnosis of ruptured papillary muscle suspected clinically.
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In a prospective study the accuracy of cross-sectional echocardiography for determination of left ventricular (LV) volume and ejection fraction (EF) was analyzed in 53 patients with coronary artery disease and compared to that of cineangiocardiography (angio). From the apex of the heart phased-array wide-angle (84 degrees) electronic echocardiograms were received in the RAO-equivalent view. Angios were obtained in a 30 degree RAO view. Using Simpson's rule, end-diastolic (EDV) and end-systolic (ESV) LV volumes were calculated and the EF derived. Left ventricular long axis was transected in eight segments, yielding seven diameters. In 50 of the 53 patients cross-sectional echocardiograms could be recorded. The correlation between cineangiocardiography and cross-sectional echocardiography for EDV was highly significant: r = 0.936, y = 0.667x + 27.1, standard error of estimate (syx) +/- 22.2 ml; for ESV: r = 0.970, y = 0.699x + 14.7, syx +/- 14.5 ml; for stroke volume: r = 0.721, y = 0.503x + 11.3, syx +/- 15.3 ml; for EF: r = 0.909, y = 0.740x + 11.3, syx +/- 6.0%. Angio mean long axis was 10.2 +/- 1.2 cm, cross-sectional echocardiographic long axis 8.7 +/- 1.3 cm. Mean LV diameter determined by cineangiocardiography was longer than when determined by cross-sectional echocardiography. The mean difference reached 2.0 cm in the middle of the LV. Our prospective comparative study revealed that LV volumes and EF were underestimated by cross-sectional echocardiography compared to cineangiocardiography because of a methodological systematic error caused by a tangential cut of the heart. In the RAO-equivalent view the "true" long axis was missed. The high corrleation coefficients, however, indicate that the "true" LV volume and EF can be calculated from the given regression equation. Serial measurements should be legitimated.
Injuries to the epiphysel plates without involvement of the epiphyses or metaphyses, such as crush fractures or pure epiphysiolysis may be difficult to diagnose radiologically. Thirteen bone scans after damage to the growth plate have been performed on eight children. These indicate that these scans are able to diagnose lesions of the epiphyseal plates at an early stage and with certainty. The scintigrams also provide information concerning the healing process of the plate; they indicate when healing has been completed and when the extremity can be used for weight-bearing again. Radiation exposure of the children during scintigraphy with 99mTc-polyphosphate is within acceptable limits.
This is a comparison of the results of 14 primary sutures of the flexor tendon, 11 secondary (one-stage) and 14 seconary (two-stage) interposition grafts. Flexion and extension of the fingers treated were best after the primary tendon suture, worst after the secondary interposition graft at one sitting. Since good results were obtained with the primary flexor tendon suture even in unclean, crushed tissues, we conclude that in children a primary tendon suture should be aimed at as a rule. Where the primary treatment is unsuccessful, the secondary two-stage procedure should be preferred to the one-stage interposition graft. The comparison also shows that the two-stage secondary procedure gives better results when the proximal tendon anastomosis is sutured near the muscle, instead of in the palm of the hand.
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