Biomedical subjects
Publications and source records attributed to H Lassmann.
A case of local gigantism of the thumb was studied by light and electron microscopy. In the lesion, proliferation of fibroadipose tissue and typical alterations of the nerves were found. The alterations in the nerve were isolated hypertrophy of the perineural cells. The relation of the changes to other peripheral nerve tumours especially in neurofibromatosis, is discussed.
A follow-up study was carried out of the clinical symptoms and the radiological and histological alterations in five cases of neurofibromatosis (Recklinghausen's disease) with onset during early childhood. The clinical manifestation of the disease was predominantly restricted to the face. In the histological ultrastructural investigation different types of neurofibroma were detected (plexiform neurofibroma, argyrophilic neurofibroma and diffuse neurofibrma). Preliminary results are presented on the basis of a correlation between the clinical findings and the histological types of neurofibroma with special reference to the demarcation of the tumours, recurrence following surgical removal and the prognosis as to the clinical course of the disease. Nevertheless, definite conclusions will be possible only by continuous observation of a larger number of patients by means of standardized clinical, radiological and histological methods of investigation.
The proliferative activity of epidermal structures was determined in 6 patients suffering from lichen planus (i.p.). By using the in vitro 3H-thymidine labelling technique, semithin Epon sections of lesional and perilesional uninvolved skin were compared autoradiographically with normal controls. The following results were obtained. The labelling index of epidermal cells was significantly increased within the i.p. papules. The mean values ranged from 41% in acanthotic i.p. to 23% in atrophic i.p. whereas in adjacent unaffected skin (15% and 11% respectively) as well as in normal controls (6%) a lower 3H-index was observed. As regards damage to basal cells within i.p. lesions, a factor--the relation between the number of basal cells in involved and uninvolved skin in reference to the epidermal length--was calculated in order to correct the autoradiographic results in involved skin. The differences between i.p. papules, adjacent skin and controls remained statistically significant even after correction. The intradermal eccrine ducts revealed a significantly increased labelling index in i.p. lesions as compared with perilesional and normal skin. In this respect no difference could be observed between the acanthotic and the atrophic variant of i.p. These findings indicate that replacement of damaged basal cells in i.p. is achieved by an increase in actively dividing keratinocytes in both epidermis and skin appendages within the lesion.
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The dissected plantar nerves of 105 patients with clinical symptoms of Morton's disease were examined under light and electron microscopy. Of the 105 cases, 75 showed characteristic neuronal lesions; in the others different pathologic substrates responsible for the clinical symptoms could be demonstrated. The nervous lesions are characterized by: 1. Thickening of the walls of the endoneurial vessels produced by multiple layers of basement membranes. 2. Edema and sclerosis of the endoneurium. In the electron microscope the endoneurium was filled by deposits of fibrils with a tubular substructure and a diameter of 100-110 A. 3. Thickening of the perineurium. 4. Degeneration of the nerve fibers without signs of wallerian degeneration or obvious reactive Schwann's cell hyperplasia. The possible pathogenetic mechanisms of Morton's disease and some clinical problems are discussed.
The cutaneous tumors of 5 patients with clinical symptoms of Recklinghausens neurofibromatosis were investigated by light and electron microscopy. Special reference was given to the study of initial changes of the disease and the structure of the nerve fascicles which end in the tumor. In 2 patients the proliferating cells were determined by using an autoradiographic technique. It was discovered that all cellular elements of a peripheral nerve are involved by the tumor formation. The results were discussed and compared with the alterations during nerve regeneration after traumatic injury.
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The structure of connective tissue fibers in cutaneous neurofibroma was investigated by normal transmission electron microscopy and by the electron microscopic dark field method. Elastic fibers were found in the periphery of the tumor nodules. Proceeding towards the center of the tumor the elastin content of the fibers diminished leaving at least a microfibrillary bundle. The collagenous fibrils normally had a diameter of 300-400 A. Only in the periphery of the tumor thick collagenous fibrils (700-800 A) comparable with those of the normal skin could be detected. In the vicinity of nerve fascicles in the tumor, numerous banded structures, so called "Luse bodies" were found.
The regeneration of transected peripheral nerves of mice was studied using autoradiographical and electron microscopical techniques. In general, maximal proliferation occurred between the 5th and 7th day after dissection and stopped when the cells emigrating from the proximal and distal stumps of the nerve started to contact one another. Special attention was paid to the reaction of the connective tissue cells of the endo-, epi- and perineurium. The perineurial cells seemed to dedifferentiate between the 3rd and 5th day after the transection and then started to proliferate into the defect. Labelled perineurial cells were completely absent, when the minifascicles were fully developed in the neuroma. The epineurial fibroblasts started to proliferate during the 1st day. Even 6 weeks after transection the multiplication rate was about ten fold that of the controls. The results are discussed with special reference to clinical nerve repair.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.