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Biomedical subjects

M Toga

Publications and source records attributed to M Toga.

At least 55 records · Page 3Linked to original sources
PubMed1985

Immunocytochemical antigens detection in human breast carcinomas: a light and electron microscopy study using avidin biotin peroxidase and preembedding method.

An immunohistochemical study was carried out on a human breast carcinoma series with the aim to delineate the technical approach to distinguish the epithelial cells from stromal nonepithelial cells in the primary tumor and in cultured tumor cells. Frozen sections from 30 unfixed breast carcinomas were incubated with mouse monoclonal antiepithelial cell membrane antibodies and then with a biotinilizated antimouse antibody and the avidin biotin peroxidase complex (ABC). Thick (100 micron) sections from fresh, unfixed tissue were similarly treated prior to the araldite embedding procedure for EM study. In all cases the epithelial tumor cells were immunostained in contrast to nonepithelial stromal cells, particularly the fibroblasts. Because standard light microscopy fails to determine the real nature of the fusiforme cultured cells, it is suggested that these techniques represent a reliable method for mammary epithelial cell identification and may further be applied on cultured tissue.

Antigens, Neoplasm↗
PubMed1984

Paired twisted filaments: a new ultrastructural marker of human pinealomas?

Paired twisted filaments (PTF) forming helices are described in tumor cells of three human pinealomas. Each filament was 8.11 +/- 1.55 nm wide. The maximal width of the helix was 16.62 +/- 2.62 nm. The periodicity of the constrictions was 26.63 +/- 4.49 nm. These characteristics appeared original, suggesting protein filaments possibly specific of pinealocytes. The similarities and discrepancies between PTF and Alzheimer's paired helical filaments (PHF) are discussed.

Adult↗
PubMed1984

Peripheral neuropathy induced by amiodarone chlorhydrate. A clinicopathological study.

Four cases of amiodarone neuropathy are reported. Patients presented a sensorimotor neuropathy with distal predominance. Improvement occurred after drug discontinuation. Nerve conduction velocities were significantly decreased. Other secondary effects of amiodarone were noted in two cases. In one case serum levels of amiodarone and N-monodesethylamiodarone were evaluated during and after treatment. Pathological study of nerve with morphometric evaluation was performed. Axonal degeneration changes were predominant in 3 cases. Aspects of segmental demyelination and remyelination were noted in one case and related to secondary demyelination. Numerous lysosomal inclusions were present in Schwann cells, fibroblasts, capillary endothelial and perithelial cells and in perineural cells. Similar inclusions have been observed in other drug-induced lipidosis. The factors responsible for this neuropathy are unknown. In one case, amiodarone-induced hepatic failure might explain the persisting high serum levels of the drug.

Adult↗
PubMed1984

Laboratory diagnosis of Mediterranean spotted fever by immunofluorescent demonstration of Rickettsia conorii in cutaneous lesions.

Indirect immunofluorescent staining was performed on cryostat sections of skin biopsy specimens from 21 patients. In six of the 11 cases finally diagnosed as Mediterranean spotted fever, coccobacillary forms of Rickettsia conorii were identified in these sections. A factor recognized as contributing to false-negative results was prior treatment with tetracycline. No false-positive results were obtained for 10 patients whose final diagnosis was not Mediterranean spotted fever. This laboratory test can aid in the early diagnosis of severe and atypical forms of Mediterranean spotted fever.

Adolescent↗
PubMed1984

Biochemical characterization of 17 beta-hydroxysteroid dehydrogenase in human meningioma.

17 beta-Hydroxysteroid dehydrogenase (E2-DH) activity was characterized on a semipurified microsomal preparation of human meningioma tissue (mean Km of 2 microM and Vmax of 500 pmol/mg protein/10 min) and then assayed in 49 meningioma specimens with high progesterone receptor and low estrogen receptor levels. Of these 49 tumors, 36% contained an E2-DH activity greater than 1,000 pmol/mg protein/10 min and similar to that of uterine myometrium. In this limited series of tumors, no correlation between E2-DH activity and progesterone receptor levels was noted.

17-Hydroxysteroid Dehydrogenases↗
PubMed1984

Immunohistochemical study of pheochromocytomas. An investigation of methionine-enkephalin, vasoactive intestinal peptide, somatostatin, corticotropin, beta-endorphin, and calcitonin in 16 tumors.

Immunohistochemical investigations were carried out on 16 pheochromocytomas for a study of their immunoreactivity to methionine-enkephalin, vasoactive intestinal peptide, somatostatin, corticotropin, beta-endorphin, and calcitonin on serial semithin araldite sections. All antiserums except anti-beta-endorphin, selectively stained a variable number of distinct tumor cells. Methionine-enkephalin-immunoreactive cells were the most frequent. The neuropeptide content of pheochromocytomas appears highly diverse and unpredictable. These findings are supportive of the concept of multisecretory APUD cells of neural crest origin and rule out any of these neuropeptides as reliable immunohistochemical markers for tumor chromaffin cells.

Adolescent↗
PubMed1984

[Alexander's disease in an adult].

A 34-year-old man developed cerebellar symptoms, palatal myoclonus and spastic paraparesis progressing over several months. During this period, acute respiratory failure occurred in two instances with evidence of central chronic hypoventilation. CT scan showed enlargement of the frontal horns and posterior fossa cisterns. Post mortem examination revealed the following features: 1) Rosenthal's fibers widespread throughout the CNS but especially in subependymal regions; 2) bilateral white matter cavitations involving the frontal lobes, hilum of dentate nuclei and bulbar pyramids; 3) microscopic pseudogliomatous foci present in several sites, especially in the fornix and midbrain tegmentum; 4) the medulla and high cervical spinal cord showed "peripheral type" myelin fibers along with Schwann cell proliferation in aberrant intra-parenchymal situation. The relationship of this case--as well as the few previous adult reports--to the well-defined infantile Alexander's disease is discussed. The possible hamartomatous nature of both glial changes and aberrant myelin production is emphasized. These various lesions, including Rosenthal fiber formation, are assumed to result from a similar--probably dysontogenetic--pathophysiological mechanism. It is suggested that Alexander's disease, in this case, should be classified among phakomatoses rather than enzymopathic leukodystrophies.

Adult↗
PubMed1983

[Contribution of electron microscopy to the diagnosis of cerebral tumors].

The authors comment on the role of electron microscopy in the diagnosis of brain tumors. This kind of morphological investigation is essential for the differential diagnosis of undifferentiated or round cell tumors, especially on small biopsies. In addition, electron microscopy clarifies the nosology of numerous entities, such as germinomas, lymphomas, astrocytic gliomas, neuronal tumors, medulloblastomas and pinealomas. Finally numerous ultrastructural details are provided, widening our knowledge of the complex pattern of brain tumors.

Brain Neoplasms↗
PubMed1983

Specific ultrastructural markers of human pinealomas. A study of four cases.

An ultrastructural study of four pinealomas was carried out to precise eventual specific markers. Dark and clear cells joined with zonulae adherents, extensive and pleiomorphous processes, a complex vacuolar system, and characteristic organelles (lysosome-like structures, clear and dense-core vesicles, vesicle-crowned rodlets and related structures, microtubular sheaves and centriolar derivatives, membranous whorls, fibrous bodies, microtubules, heterogeneous cytoplasmic inclusions) offered a typical pattern. No correlation could be made between the histological and ultrastructural features. The authors stress the ultrastructural similarities between the human tumor cells and the mammalian pineal cells. Pinealomas appeared as a morphological entity distinct from neuronal and astrocytic tumors.

Adolescent↗
PubMed1982

Calcitonin, somatostatin and ACTH immunoreactive cells in a case of familial bilateral thyroid medullary carcinoma.

Bilateral medullary carcinoma of the thyroid (MCT) was discovered in a symptomless patient of a high-risk MCT family. Raised serum calcitonin responding abnormally to pentagastrin led to a thyroidectomy. Grossly, the thyroid showed one nodule in the upper third of each lobe. Light microscopy revealed typical MCT with amyloid deposits. Nontumoral thyroid tissue showed C cell parafollicular hyperplasia. Electron microscopy detected intracellular secretory granules (mean diameter, 150 nm) and typical amyloid fibrills. Immunochemistry revealed numerous calcitonin immunoreactive cells in the nodules, in normal para and intrafollicular C-cells and hyperplastic C-cells. Somatostatin and ACTH were detected in certain tumor cells, but not in normal and hyperplastic C-cells. MCT hormonal production potential is discussed.

Adrenocorticotropic Hormone↗
PubMed1982

Changes in the nigrostriatal system following microinjection of an unconventional agent.

The effect of apomorphine, a direct dopamine receptor agonist, was studied in golden hamsters after unilateral injection of scrapie agent (strain 263K) into the nigrostriatal system. Twenty-five received an injection into the left striatum and 24 into the left substantia nigra. Varying volumes (5, 1 and 0.5 microliterss) and dilutions of the homogenate (10(-2), 10(-3), 10(-4)) were used. The duration of the incubation period (delay of appearance of clinical signs of the disease) was dependent on the dose of the agent used: it varied within a range of 72 +/- 5 days (5 microliter 10(-4) and 123 +/- 8 days (0.5 microliter 10(-4)). Apomorphine-induced circling behavior appeared after an average of 84 +/- 15 days post-injection and this delay was closely related to the dose of agent. The direction of the rotation dependent on the site of injection: most of the animals circled towards the inoculated side after striatal injection and away from it after inoculation in the substantia nigra. In the group of animals inoculated in the substantia nigra with 0.5 X 10(-4) microliters, 6 presented the clinical phase of the disease and showed circling behavior but no clinical signs when they were killed 200 days post-injection. However, neuropathological studies revealed characteristic foci of vacuolation in the brain stem. Apomorphine-induced circling behavior can only be contained by replication of scrapie agent into the nigrostriatal neurons and the subsequent imbalance between the two sides which it reveals. Circling behavior and clinical signs of the disease can be temporally dissociated: low doses of agent slightly extended the circling behavior latency, whereas the incubation period was considerably increased. Circling behavior and neuropathological lesions in nigrostriatal system were not closely related.

Animals↗
PubMed1982

Complex cerebral tumor with evidence of neuronal, glial and Schwann cell differentiation: a histologic, immunocytochemical and ultrastructural study.

An unusual cerebral tumor is reported in a ten-month-old boy. The tumor was large (10 cm x 6 cm), firm and included several cysts. Light and electron microscopy showed a striking cellular pleomorphism. Typical neurosecretory ganglion cells were observed, always surrounded by Schwann cells. Amyelinic neurites, clusters of Schwann cells, fibroblasts and numerous foci of GFA positive astrocytes composed the tumor. These features were compared with the rare previous electron microscopic reports of cerebral neuronal tumor of the central nervous system. A dysembryoplastic origin from the neural plate was retained to explain the growth of such a complex tumor.

Brain Neoplasms↗