Biomedical subjects
U Engel
Publications and source records attributed to U Engel.
The aortic wall: an in vitro study of the double-line pattern in high-resolution US.
An in vitro study of macroscopically normal aortas from human cadavers was performed with high-resolution ultrasound (US). Rectangular pieces of 10 fresh aortas were submerged in saline solution and scanned from the intimal side. On US images a characteristic double-line pattern, consisting of an inner and an outer echogenic line separated by a relatively hypoechoic line, was seen. This configuration was initially interpreted as tunica intima, tunica media, and tunica adventitia. The thickness of each layer on the US images was measured by means of a computer-assisted procedure and on histologic specimens was measured by means of stereomicroscopy. The correlation between the two measurements was poor. Experiments in which intima and part of the media were removed did not change the US appearance. Plexiglas, metal plates, and plastic foil showed a similar double-line pattern. A needle experiment disclosed that the inner echogenic and the hypoechoic lines were displayed in front of the true water-tissue interface, which was represented by the outer echogenic line. The authors conclude that the double-line pattern is thus an artifact.
[The necessity of intraoperative identification of the contralateral lobe in "struma uninodosa"].
Between July 1st, 1988 and July 31st, 1989 we registered 74 consecutive patients with a unilateral goitre. In all these patients the preoperative sonography showed no pathologic finding in the contralateral lobe of the thyroid. In 16 cases we found and resected nodules in the lobe, which was supposed to be normal. A consequent exposure of the whole thyroid gland, independent of the preoperative sonographic finding, principally is necessary. So, the rate of "false" goitre recurrences might be decreased.
[Identification of the recurrent laryngeal nerve in thyroid gland surgery--a status determination].
The recurrent laryngeal nerve palsy is the most important complication in thyroid surgery. It seems to be possible to reduce the rate of palsies by consequently identifying the recurrent laryngeal nerve. A comparison of statistics out of the literature with and without identification of the recurrent laryngeal nerve shows this. A follow-up of our patients of the years 1980-1982 (1312 operations) confirms this finding.
[Technics and complications in reinterventions on the thyroid].
In preference to the two long-established operative procedures for recurrent goitre - extracapsular and intracapsular resection - we have introduced meticulous preparation between the thin capsule around the recurrent goitre and the more solid external capsule in a procedure which combines the advantages of both older methods and avoids most of their pitfalls. The recurrent laryngeal nerves and the parathyroids are always outside the external capsule. The incidence of injury to these structures is minimised by this procedure. From 1980-1985 we performed 2575 thyroid operations, of which 165 operations were for recurrent goitre (6.4%), bilateral in 89 cases. Two patients died of cardiopulmonary complications (1.2%). Preoperative laryngeal nerve palsy was present in 21 cases, postoperative acquired nerve injuries occurred in 28 patients, all in all 31 nerve paralysis (18.8%), or 12.2% when compared with nerves at risk. Eight patients suffered laryngeal nerve palsy on both sides (five with preoperative nerve palsy on one side). Eleven patients showed normal function of laryngeal nerves on follow-up, whilst permanent nerve palsy was found in seventeen cases (10.3%), or 6.7% when related to nerves at risk. Hypoparathyroidism was found in 7 patients of which 4 cases showed permanent changes (2.4%).
Failure in school, family conflicts, and psychosomatic disorders in adolescence.
Adolescence is considered to be a transitory phase in the life course. It is hypothesized that failure in school, which carries the risk of an occupational and social "downward mobility" in the future life course in comparison to the family of origin, can function as a social "stressor" which has detrimental effects on the social and emotional climate within the family and manifests itself in symptoms of stress such as psychosomatic disorders. The results are based on a questionnaire survey carried out with a representative sample of 1717 students aged 13-16 in West Germany. The data support the hypotheses: psychosomatic symptom frequency is reinforced when adolescents experience failure in school and social and emotional conflict in their relationships with parents. Multivariate analysis shows that these effects are interconnected: failure in school has a direct effect on the frequency of psychosomatic disorders, and an indirect effect by influencing social and emotional conflicts in the family. The underlying causes for the tensions between adolescents and their parents are conceived in the social and economic opportunity structures of the society.
[Ultrastructural aspects of intra- and extravascular coagulopathy in lung cancer].
Four cases of lung cancer were analysed for aspects relating to optical light microscopy and ultrastructure of coagulation disorders. Criteria of intravasal coagulopathy were positively verified from all four cases and were found to have grown manifest in the form of prethrombi in veins, arterioles, and venules, masses of fibrin monomer in capillaries, and the sludge phenomenon. Extravasation of fibrin was also observed around highly differentiated cancer cells as well as in tumour stroma and in necrotic foci. Most of the fibrin was identified in the forms of monomers and their ultrastructural variants. Morphological criteria of locally delimited coagulation disorders in the microcirculation of tumours are discussed together with the role played by fibrin in growth and dissemination of neoplasms.
Regional variations in histomorphometric bone dynamics from the skeleton of an osteoporotic woman.
Histomorphometric evaluation of bone formation in an intravital tetracycline-labeled skeleton of a suddenly deceased osteoporotic woman is presented. The 24 skeletal sites investigated displayed substantial regional variations which, for two out of four cortical bone dynamics and all trabecular bone dynamics, were significantly higher than the intraspecimen variation. Poor agreement was found between bone formation in left- and right-sided iliac crest specimens. Furthermore, no agreement was found between trabecular bone formation and amount of hematopoietic bone marrow. With all the limitations that the study of a single patient involves it is suggested that bone biopsy in individual patients should not be the only basis for therapeutic decisions in postmenopausal osteoporosis; amount of hematopoietic marrow does not seem to influence bone formation; and bone formation in the skeleton displays large regional variations, which are larger for the fraction of labeled surfaces than for appositional rate.
Renal oncocytoma.
Renal oncocytomas are usually regarded as benign tumors. Metastases from renal oncocytomas to regional and especially distant lymph nodes are extremely rare. This paper describes five cases of renal oncocytomas, one of which had a malignant behaviour with metastases to regional and distant lymph nodes.
[Tumors of the anterior mediastinum--surgical treatment and prognosis].
This paper reports on 96 mediastinal tumors situated exclusively or mainly in the anterior mediastinum. Early surgical intervention is always indicated to establish the diagnosis and to ensure as radical a tumor resection as possible. The surgical approach depends on the tumor size and localization and is made either by sternotomy or thoracotomy. The prognosis depends on the histological classification of the tumors: out of 30 patients with lymphomas, 19 survived as compared to 10 out of 21 patients with thymoma and 15 out of 18 patients with mesenchymal tumors. Of 16 patients with endothoracic and retrosternal goiters, none died of a cause connected with the goiter and nine out of 11 patients with mesodermal tumors survived. The indication for surgery should be established extensively, since one third of the tumors is malignant and the surgical lethality (1.8%) is very low.
Characteristic and specific histological findings in rheumatoid pleurisy.
The histological findings in rheumatoid pleuritis (RP), as seen in thoracoscopical biopsies, are found to be: A slightly inflamed stroma with a wave-like surface due to vessel-containing flattened papillae. The surface is covered by layers of pseudostratified epithelioid cells and scattered multinucleated giant cells, layers that easily detach as membranes, leaving the stroma surface "naked". These findings, in combination with the absence of mesothelial cell covering, are viewed as characteristic and specific, as based on a blind review of 17 pleural biopsies from RP patients and 14 biopsies from a control group.
Rheumatoid pleurisy. Specificity of cytological findings.
The cytological findings in pleural exudates from patients with rheumatoid arthritis are epithelioid cells, giant cells, cholesterol crystals and an amorphous granulated material. An important additional feature, we find, is lack of mesothelial cells. Based on 23 pleural fluids from 7 patients with rheumatoid arthritis and 44 pleural fluids from patients with various other diseases, a blind study showed, that these typical cytological findings in combination with lack of mesothelial cells were specific in pointing towards the determined diagnosis rheumatoid pleurisy.
Neoplasm to neoplasm metastasis. A renal oncocytoma with metastatic bronchogenic carcinoma.
An unusual case of metastasis of neoplasm to a benign neoplasm is reported. The initial malignancy, a small-cell bronchogenic carcinoma, was found to have metastasis to a renal oncocytoma. A review of the literature indicates, according to our knowledge, no similar case.
[Therapy of ventricular tachyarrhythmia with disopyramid phosphate].
A controlled multicenter study has been carried out in 46 patients with ventricular tachyarrhythmias to define the antiarrhythmic effect of disopyramide phosphate. Monitoring of cardiac rhythm was performed during the whole study period by ambulatory Holter recording. The daily dose of disopyramide was 600 mg. It was found that disopyramide caused a reduction of at least 80% in the number of premature ventricular beats in 72% of the patients. Episodes of ventricular tachycardia were effectively suppressed in 65% of the patients. In 24 patients there was a reduction in the severity of the observed ventricular arrhythmias of at least one class in the classification of Lown. Analysis of the results showed a relationship between the antiarrhythmic effect and group mean plasma concentration of disopyramide.
[Complications in thyroid operations].
Serious postoperative complications following thyroid surgery are to be expected in approximately 3% of cases. Intraoperative blood loss, usually in the region of the superior thyroid artery, should be minimised by careful preparation. Damage to recurrent laryngeal nerves is usually indirect due to stretching. Damage to the recurrent laryngeal nerves can be minimised by thoroughly searching for them. Permanent tetany may be avoided by demonstration and sparing of the parathyroid bodies and their blood supply. Postoperative complications of the various forms of breathing disturbance, secondary bleeding, hyperthyroid crises and hypothyroidism will be discussed in detail.
The systolic time intervals in thyroid dysfunction.
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[The systolic time intervals in functional disorders of the thyroid: a simple and fast screening test].
The systolic time intervals (LVET, PEP, and ratio LVET/PEP) were determined in 53 patients presenting with signs or symptoms of thyroid dysfunction. Patients with clinical evidence of congestive heart failure, with arterial hypertension or old myocardial infarction, and patients receiving cardioactive drugs, were excluded from the study. Thyroid function was evaluated by means of T3-RIA, serum thyroxin and TRH stimulation test.
Presence of muscarinic inhibitory and absence of nicotinic excitatory receptors at the terminal sympathetic nerves of chicken hearts.
Nicotine (2 X 10(-4) M) or acetylcholine (5.5 X 10(-4) M) in the presence of 3 X 10(-6) M atropine did not increase the rate or amplitude of contraction in isolated atria or ventricular strips of the chicken heart; both drugs also did not cause an output of noradrenaline or adrenaline and did not evoke antidromic discharges in the right sympathetic nerves of isolated perfused chicken hearts. In contrast, "high K+-solutions" evoked an output of noradrenaline and adrenaline and caused a burst of antidromic discharges. Dimethylphenylpiperazine (DMPP; 3.1 X 10(-4) M), by a tyramine-like action, elicited a small output of noradrenaline and increased rate and amplitude of contraction" but did not evoke antidromic discharges. The noradrenaline output caused by DMPP was not reduced by lowering the extracellular Ca2+ concentration from 1;8 to 0.1125 mM.-Acetyl-choline (10(-5) and 10(-4) M)inhibited the noradrenaline and adrenaline outputs evoked by electrical stimulation of the right sympathetic nerves (3 HZ, 1 ms, 30 V); the inhibition was blocked by 3 X 10(-6) M atropine.-It is concluded that the terminal parts of sympathetic nerves of the chicken heart possess muscarinic inhibitory receptors but lack nicotinic excitatory receptors. Thus prejunctional nicotinic receptors are not an integral part of the terminal sympathetic neurone otherwise they would be present at this neurone in all species.