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Biomedical subjects

H Kroh

Publications and source records attributed to H Kroh.

At least 55 records · Page 3Linked to original sources
PubMed1983

Transformation of oligodendroglia: a para- or preneoplastic effect of ethylnitrosourea on mouse brain.

The aim of this EM study was to assess the relationship of demyelination changes induced in mouse brain by a carcinogenic substance to the early steps in the evolution of neoplastic disease. The investigation on the 25 experimental mice injected at various stages of age with ethylnitrosourea revealed demyelination foci in three animals and interfascicular nests of abnormal cells in seven animals, the latter most probably being of oligodendroglial origin. The nest cells were characterized by their large size and a multitude of interdigitated cytoplasmic processes forming complicated membranous patterns. The abnormal development of oligodendroglial cytoplasmic processes is considered to be the cause of the demyelination. This previously unknown form of oligodendroglial transformation may consist in either the earliest preneoplastic changes or represent a reactive, paraneoplastic type of alteration.

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PubMed1981

Spinous extensions on ciliary necklaces in ependymal cells.

In ependymal cells of the mouse the neck region of all cilia examined by means of transmission electron microscopy exhibited rows of electron-dense spines. THese structures correspond to ciliary necklace reported from freeze-etch studies, a structure presumed to serve as an energy-regulating system in motile cilia.

Animals↗
PubMedDate not supplied

[Light microscopic and ultrastructural features of nerve fibres in glomus tumor in two patients with long-term pain].

Morphologic features of nerve fibres in two cases of glomus tumour, localized in thigh skin of 57- and 72-year-old men are reported. In the patients, the paroxysms of severe pain occurred 10 and over 11 years respectively. Histological, immunohistochemical and ultrastructural examination revealed tumour cells with features resembling that of epithelioid smooth muscle cells of normal glomus body. In addition, NF-immunopositive nerve fibres were identified in connective stroma of the tumour. Ultrastructural examination revealed bundles of thin, nonmyelinated axons, surrounded by Schwann cell cytoplasm. The majority of axons were under 0.5 micron in diameter and contained densely packed neurofilaments, whereas only few axons of larger diameter exhibited electron-lucent axoplasm with granular and clear vesicles. The bundles of nonmyelinated nerves were observed always within spaces filled by collagen fibrils and did not show any special relationship to glomus cells.

Aged↗
PubMedDate not supplied

[Anaplastic oligoastrocytoma of the spinal cord: diagnostic difficulties. Case report].

The authors report a rare case of 49-years old woman with rapidly progressing anaplastic oligoastrocytoma primarily localized in the spinal cord. Increasing spastic paresis of the right lower limb was concomitant with decrease in superficial sensibility in this limb and the right side of the trunk below Th10 level, suggested a lesion within the spinal cord. However, it was the difficult confirming the diagnosis by spinal MR imaging, and the negative result of the first MR examination (performed 5 weeks after manifestation of first clinical symptoms of the disease) delayed surgical treatment. During the next 3 weeks the neurological syndrome increased to spastic paraparesis with sphincters dysfunction and decrease in superficial and vibratory sensibility within the lower limbs and the trunk below the Th10 level. The second MR examination of the spine revealed an intraspinal tumour at Th8-Th10 levels. Surgical (partial excision of the tumour) and radiation treatment was given. Histopathological examination of tumour tissue showed the presence of anaplastic oligoastrocytoma. During the follow-up of our patient we found cerebral foci, probably of metastatic origin ascending with cerebrospinal fluid. More than 5 months after the diagnosis was established the patient died of primary disease. The imaging parameters of both spinal MR examinations were similar, however, on second examination narrower field of vision was used. In both cases Magnevist was administered. Discussing factors which might be responsible for the false-negative result of spinal MR examination--the examination of choice for detection of proliferative transformation--the authors take artefacts connected with respiratory and circulatory function, peristaltic movements, and with field of vision into consideration.

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