Biomedical subjects
Publications and source records attributed to H Vogel.
Drainage of a hepatic amoebic abscess by puncture guided by ultrasonography is described by means of an example. The treatment by puncture has the advantage of shortening clinical treatment. It should be combined with pharmacotherapy.
Meningiomas are composed of cells which display both mesenchymal and epithelial features. To investigate the epithelial nature of these cells, we studied the distribution of epithelial membrane antigen (EMA) in 22 meningiomas; for comparison, we also studied eight central schwannomas, neoplasms with which meningiomas sometimes may be confused histologically. All 22 meningiomas (12 transitional, six meningotheliomatous, three fibroblastic, and one psammomatous) demonstrated immunoreactive EMA, whereas all eight schwannomas were EMA-negative. There was no consistent relationship between histologic growth pattern and nature of EMA staining in the meningiomas: meningothelial areas, spindle cell areas, and whorls all showed EMA immunoreactivity of varying degrees. We also evaluated the distribution of S-100 protein and keratin in these tumors. All schwannomas showed diffuse S-100 positivity, which was often more intense in the nuclei than in the cytoplasm. In nine meningiomas (41%), S-100 immunostaining was observed, but this was usually focal, and nuclear staining was never more intense than cytoplasmic staining. One meningioma, but none of the schwannomas, showed clusters of keratin-positive cells. We conclude the following: EMA immunoreactivity is a characteristic feature of meningiomas, regardless of pattern of growth, and the combination of immunoperoxidase staining for EMA and S-100 protein may be used to distinguish meningiomas from schwannomas in problematic cases.
We studied three patients with acquired immune deficiency syndrome (AIDS) and progressive polyradiculopathy. Postmortem examination of one patient disclosed extensive necrosis, inflammatory infiltrates, and focal vasculitis of spinal roots. Typical cytomegaloviral (CMV), intranuclear, and intracytoplasmic inclusions were noted within enlarged endoneurial and endothelial cells. Progressive polyradiculopathy is an unusual complication of AIDS; CMV may be the causative agent in certain cases.
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Biliary ascariasis is a complication of intestinal ascariasis. This results in characteristic findings in the intravenous cholangiocholecystogram and in the sonogram. Characteristic signs of biliary ascariasis are, in the longitudinal section, the "strip sign", "spaghetti sign", "inner tube sign", and in transverse section "a bull's eye in the triple O". The helminth can travel from out of the biliary duct system back into the intestines, so that control examinations can even be negative.
Postoperative angiography may provide clues as to vascular displacement in the wake of surgery which, in the abdominal region, may have been caused by removal of organ parenchyma or relocation of intestinal loops. Irregularities in vascular lumens may be indicative to consequences of adhesions or to infiltrative tumour growth. Interventions with the vascular system appear in the angiogram as dilatation or stenosis. Reference is made to vascular changes following kidney transplantation.
The magnetic resonance tomogram visualises the corpus spongiosum, the corpora cavernosa, the fascia penis profunda, the septum and the dorsal vein of the penis. These structures can be separated from the skin and from the glans penis. Changes of shape are still the essential criteria of assessment. At present it does not seem possible to be able to differentiate between diseased and healthy areas if the connective tissue structures of the penis (e.g. in induratio penis plastica) do not show any change of shape. Compared with other imaging methods, imaging on different levels offers advantages, and so does the simultaneous imaging of the structures of the penis, of its environment and of the adjacent organs. We can assume that the magnetic resonance tomogram will supply essential additional information for clinical diagnosis and practice in conditions like induratio penis plastica, intersexuality, tumours of the prostate gland, and in postoperative follow-up, for example after surgery for priapism.
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Comparison of MRI tomograms with anatomic sections shows that the limits of the joint cartilage do not correspond to the hitherto assumed zone of the more intensive signal. This intensive signal may be caused merely by the surface of the cartilage. Considering its extent, the signal-free zone bordering on this zone should also be cartilage. Since, e.g., in the knee, there is no subchondral substantia corticalis and, as is clearly recognizable in the anatomic section, bone marrow extends as far as the cartilage, this signal-poor zone should also correspond, at least in part, to cartilage. It is conceivable that the boundary areas in the MRI tomogram (in this case the cartilage surface) are demonstrated and that the signal behavior of the hyaline joint cartilage is not uniform and applicable to all sections. This also applies to fibrous cartilage.
We compared x-ray films of 204 patients, evaluating plain radiographs, computer tomograms and myelographies. This study showed that plain radiographs serve as a guide, enabling to localise the level at which bone defects have occurred as a result of surgery. Conventional tomography is important for detecting changes associated with postoperative discitis. In about 50% of the patients, computed tomography enables satisfactory indication for a second intervention if used together with plain roentgenography and clinical examination. Myelography remains an indicated procedure if the disease pattern is not clear and if findings are ambivalent.
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X-ray examination of the oesophagus can lead to contact between the contrast medium and the lungs, connective tissue in the throat, and the mediastinum, pleura and peritoneum. The hyperosmolar iodine-containing contrast media used so far produce short-term displacement of liquid and local irritation. Long-term changes have not been reported. Contrast media containing barium sulphate will hardly produce irritation but may lead to chronic foreign body irritation; they should not be used if they are likely to come into contact with the pleura and peritoneum. Both water-soluble iodine-containing contrast media and barium sulphate-containing contrast media have resulted in deaths due to pulmonary inundation. In case of suspected disturbance of swallowing or perforation, a water-soluble contrast medium should be used at first. If there are no abnormal conditions, examination can be continued with barium sulphate contrast media. The new isoosmolar water-soluble contrast media offer interesting possibilities of detail improvement. Their better tolerance with satisfactory imaging properties should be established by animal experiments and by clinical tests.
The secondary structure of the lactose permease of Escherichia coli reconstituted in lipid membranes was determined by Raman spectroscopy. The alpha-helix content is approximately 70%, the beta-strand content below 10% and beta-turns contribute 15%. About 1/3 of the residues in alpha-helices and most other residues are exposed to water. Employing a method for structural prediction which accounts for amphipathic helices, 10 membrane-spanning helices are predicted which are either hydrophobic or amphipathic. They are expected to form an outer ring of helices in the membrane. The interior of the ring would be made of residues which are predominantly hydrophilic and, evoking the analogy to sugar-binding proteins, suited to provide the sugar binding site.
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