[131-iodine meta-iodobenzylguanidine scintigraphy and therapy in malignant pheochromocytoma].
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3-Iodobenzylguanidine↗
Biomedical subjects
M Thelen
Publications and source records attributed to M Thelen.
[Lymphoepithelial carcinoma of the nasopharynx: the treatment results following radiotherapy].
Data of 17 patients with lymphoepithelial carcinoma of the nasopharynx treated with telecobalt were reviewed. The follow-up period was five to nine years. 16/17 patients had lymph node metastases at the initial presentation. Cervical lymphadenopathy was the only tumor symptom in seven patients. The overall five-year survival was 70% (12/17 patients), the disease-free survival 47% (8/17). 2/10 patients survived seven years. Local recurrence in the nasopharynx was seen in 5/17 patients, recurrence at neck sites in 7/17. 5/7 lymph node recurrences developed outside the radiation field. Half of the recurrences appeared late (three to six years after radiotherapy). In 8/9 patients recurrence preceded the hematogenous spreading of the carcinoma. Therapy of lymphoepithelial carcinoma of the nasopharynx should always include radiation of the primary tumor and bilateral cervical lymph nodes with 60 to 70 Gy.
Carcinoma, Squamous Cell↗
[18 years after a penetrating heart injury: follow-up].
This report presents a case of penetrating chest trauma leading to pericardial tamponade and ventricular septum defect successfully resuscitated by surgery in 1968 in an 11-year-old boy. 10 years later a first-size calcified hematoma was removed. However the 30% left to right intracardiac shunt flow as established by complete heart catheterization prior to surgery was not corrected. Non-invasive methods were used to assess cardiac function 18 years after the initial event including physical examination, chest X-ray, thoracic computer tomography, ECG, 24 h Holter monitoring and exercise testing, combined with myocardial scintigraphy and radionuclide angiography and echocardiographic techniques using the transthoracic and the transoesophageal approach. The diagnostic value of echocardiographic examinations is emphasized with special reference to contrast- and Doppler-echocardiography including the color-coded Doppler-flow-imaging technique.
Adult↗
[Reuse of angiography catheters. I. Principles and problems of safe reuse].
Recycling and resterilisation of throwaway articles--in radiology especially of catheters used in angiography--has become widespread to save costs. Although extensive experimental work in this field is still lacking, criteria have been set up as guidelines to ensure safe recycling. These are subdivided into three parts: Cleaning--sterilisation--material testing. Experimental studies have been reported on sterilisation only proving the inadequacy of two ethylene oxide methods conventionally used in hospitals.
Angiography↗
[Diagnostic value of sonography, computerized tomography and lymphography in malignant lymphoma].
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Humans↗
New insights on the cytochrome c oxidase proton pump.
Cytochrome c oxidase vesicles were used to show that, under appropriate experimental conditions: (1) no net deprotonation of the vesicular membrane or of the incorporated enzyme occurs during the oxidation of ferrocytochrome c; (2) the pH equilibration kinetics of a respiration-induced pH gradient across the bilayer are a simple function of the ohmic proton-conductance properties of the membrane; (3) a fairly constant stoichiometry (0.8-0.7) of the numbers of protons pumped per molecule of ferrocytochrome c oxidized, i.e. the H+/e- ratio, over a wide range of dioxygen molecules reduced (1-12) is observed.
Dialysis↗
Proton translocation by a native and subunit III-depleted cytochrome c oxidase reconstituted into phospholipid vesicles. Use of fluorescein-phosphatidylethanolamine as an intravesicular pH indicator.
The existence of a proton pump associated with bovine cytochrome c oxidase (EC 1.9.3.1) has over the last few years been a matter of considerable dispute. In an attempt to resolve some of the problems with the measuring system we have synthesized fluorescein-phosphatidylethanolamine which when reconstituted with cytochrome c oxidase into phospholipid vesicles provided a reliable indicator of the intravesicular pH. It was observed that cytochrome c oxidase catalyzed the abstraction of almost 2 protons from the intravesicular medium/molecule of ferrocytochrome c oxidized. In parallel experiments whereby the extravesicular pH was measured with an electrode it was found that the enzyme appeared to be responsible for the appearance of almost 1.0 proton/molecule of ferrocytochrome c oxidized. Taken together these data unequivocally demonstrate that cytochrome c oxidase behaves as a proton pump. Furthermore, the other proton which was abstracted is believed to be used for the process of the reduction of oxygen. Similar experiments were performed with a cytochrome c oxidase preparation which was devoid of subunit III. Under these circumstances the enzyme appeared to be unable to translocate protons across the vesicular membrane but was competent to abstract protons from the intravesicular medium for the reduction of oxygen.
Animals↗
[Quantitative cardiac computed tomography].
The scope and limitations of quantitative cardiac CT have been evaluated in a series of experimental and clinical studies. The left ventricular muscle mass was estimated by computed tomography in 19 dogs (using volumetric methods, measurements in two axes and planes and reference volume). There was good correlation with anatomical findings. The end-diastolic volume of the left ventricle was estimated in 22 patients with cardiomyopathies; using angiography as a reference, CT led to systematic under-estimation. It is also shown that ECG-triggered magnetic resonance tomography results in improved visualisation and may be expected to improve measurements of cardiac morphology.
Animals↗
[Computed tomography, magnetic resonance tomography and echocardiography in hypertrophic cardiomyopathy].
The value of echo-cardiography, CT and magnetic resonance tomography was evaluated in 10 patients with hypertrophic cardiomyopathy. Echocardiography made the diagnosis in most cases. The diagnostic criteria depended on functional and morphological changes. CT and magnetic resonance can show thickening in the myocardium, either symmetrical or asymmetrical. Magnetic resonance tomography provides excellent demonstration of the myocardium and accurate delineation of the degree of hypertrophy. It is well suited for measuring cardiac wall thickness.
Adolescent↗
New approaches to the study of cellulose biosynthesis.
Examples of a variety of approaches for studying the mechanism and regulation of cellulose biosynthesis are presented. Attempts to demonstrate conclusively a cellulose synthase activity using membrane preparations derived from higher plants have not been successful; the predominant UDP-glucose: beta-glucan-beta-glucosyltransferase detected in these preparations is a beta-(1----3)-glucan synthase that is dependent upon Ca2+ and a beta-glucobiose, such as laminaribiose or cellobiose, for activity. Xyloglucan glucosyltransferase activity is detected in all plant preparations examined and, in cotton fibres, the activity of this enzyme correlates well with the level of xyloglucan found in the fibre. Low activity for a Mg2+-dependent beta-(1----4)-glucan synthase is found in extracts from soybeans and mung beans, but not cotton fibres; this enzyme could represent either a dissociated form of xyloglucan glucosyltransferase or a partially latent form of cellulose synthase. In vitro translation of RNA from developing cotton fibres shows notable increases in the level of several relatively abundant translatable mRNAs associated with the time of onset of secondary-wall cellulose synthesis. In order to determine whether these apparent changes in gene expression represent enhanced expression of specific genes required for cellulose synthesis, several strategies are being developed for identification of specific polypeptides required for this process. One strategy involves the successful development of a technique for detection of glucan synthase activity in acrylamide gels, a technique that should prove useful for characterization of the polypeptide composition of such enzymes. We have also synthesized a photoaffinity analogue of 2,6-dichlorobenzonitrile (DCB), a potent and specific inhibitor of cellulose synthesis. The analogue is also an effective inhibitor in vivo, and upon ultraviolet irradiation of extracts in the presence of the radioactive analogue, we observe a relatively specific labelling of a polypeptide of 18 X 10(3)Mr. Finally, we have studied the spatial regulation and structural requirements for cellulose synthesis in internode cells of the alga Chara corallina. Cellulose deposition in vivo shows spatial localization, which correlates with acid and base bands along the cell. Using internodes perfused with solutions containing UDP-[14C]glucose and subsequently ligated, we were able to demonstrate synthesis of a highly insoluble cell-wall-localized glucan, thus offering hope that Chara can be developed as another useful system for studying the mechanism and regulation of cellulose synthesis.
Cell Membrane↗
[Polyurethane positioning devices for radiotherapy].
A simple and cheap method is described for the manufacturing of individual positioning aids made of foamed polyurethane. Some examples are given to demonstrate the applicability of these positioning aids for the irradiation of different body regions. The reproducibility of the radiation field in the head and neck area was investigated with and without positioning aid. It was proved that the field is adjusted more exactly when positioning aids are applied. The dosimetric investigations performed showed a negligible influence of foamed polyurethane on the radiation quality. So the positioning aids could be left within the radiation field when drawing the field borders.
Humans↗
On the logic of the application of double-inhibitor titrations for the elucidation of the mechanisms of energy coupling.
In the last couple of years the chemiosmotic hypothesis has been severely criticised, such that many research groups now consider it to be a less than exact description of biological energy transduction. The most potent experimental support for this view is based upon the technique known as the double-inhibitor titration [e.g., (1982) Biochem. J. 206, 351-357]. The results of such experiments have been considered by many to exclude 'unequivocally' the chemiosmotic coupling model. It will be shown that such unequivocal statements are not possible. An argument is put forward which shows how the chemiosmotic model may explain these titrations without any further elaborations of the original hypothesis.
Bacteria↗
The use of fluorescein-dipalmitoylphosphatidylethanolamine for measuring pH-changes in the internal compartment of phospholipid vesicles.
The synthesis and characterisation of fluorescein-phosphatidylethanolamine (FPE) is described. The effects of dielectric constant, ionic strength and ambient pH upon the optical absorbance properties of FPE are presented. It is shown that under appropriate conditions, FPE rapidly and quantitatively reports the pH of the aqueous bulk phases when incorporated into phospholipid vesicles. It is also shown that, when the external medium is highly buffered, FPE is capable of specificity reporting only the pH of the intravesicular compartment. The application of FPE for studies of intravesicular pH changes of reconstituted membranous protein systems is discussed.
Electric Conductivity↗
[Survey echocardiography. A comparative evaluation of enlarged heart chambers in the echocardiogram and the plain x-ray].
Eighty patients with various types of heart disease were examined by radiography and sectional studies of the heart on the same day. These were compared with 2-dimensional examinations of the chambers during end-diastole. It was found that echocardiography may demonstrate dilated chambers due to a cardiomyopathy where the plain radiograph is entirely normal. Radiographic enlargement of the left side of the heart is not necessarily due to dilatation of the left ventricle, but can also be caused by gross hypertrophy. Echocardiography is indicated for the investigation of cardiac enlargement due to multivalvular disease, cardiomyopathy, combined left and right cardiac insufficiency and the exclusion of pericardial effusions.
Cardiomegaly↗
[Removal of retained bile duct stones through the T-tube drain].
Within seven years 23 patients were treated postoperatively by percutaneous bile stone extraction. This procedure was successful in 18 patients. Although an interval of 5-7 weeks between choledochotomy and percutaneous extraction is recommended, the procedure was done 11 to 31 days after surgery with no negative effects. In six cases the stones had to be dislodged into a more favorable position with a Fogarty-type balloon catheter. The papilla of Vater was dilated in two cases. With the development of newer techniques trans-T-tube extraction remains the treatment of choice in retained intra- and extrahepatic bile duct stones.
Adult↗
[Sonography of the thyroid gland. Volume determination and morphologic correlation of echo and tissue structures].
The volume of 15 autopsied thyroid glands was determined by fluid displacement and compared with their sonographically obtained stereometric volumes. Maximum variation was 8.6%. Thyroid volumes were measured by ultrasound in 100 volunteers between ages 15 and 36. Total mean value was 19.8 ml. with a mean value of 22.1 ml. in the male group and 17.8 ml. in the female group. 20 volunteers had an additional scintigraphic examination. The thyroid volumes estimated by scintiscanning differed up to 85% with the volume measurements from sonography. Sonography scans were obtained from 6 autopsied thyroid glands and compared with the corresponding tissue slices. Tissue structures were reproduced with great accuracy by ultrasound.
Adolescent↗
[Transabdominal CT-guided sympathectomy].
A new technique for lumbar sympathectomy is described. It consists of CT-guided trans-abdominal fine needle puncture and injection of alcohol. The technique is simple and well tolerated by the patient, and it permits accurate application of the alcohol. Complications have so far not been observed.
Aged↗
[Echocardiographic studies before and after a 100-mile race on 21 female athletes].
Two-dimensional echocardiography can provide better information than conventional radiological volume measurements concerning the amount of hypertrophy and dilatation, which contribute to the cardiac enlargement found in athletes. Linear cardiac measurements in standardised planes were obtained by two-dimensional echocardiography; the findings in 21 women athletes obtained before and after a 100-mile race were compared with a number of normals. All cardiac chambers were found to be equally enlarged and the aortic root and the ascending aorta were dilated. The generalised dilatation of the heart must be due to increased ejection volume in these athletes.
Adult↗