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F Michetti

Publications and source records attributed to F Michetti.

At least 55 records · Page 3Linked to original sources
PubMed1984

Detection by S-100 immunolabelling of interdigitating reticulum cells in human thymomas.

In the light of recent findings concerning the presence of S-100 antigen in interdigitating reticulum cells (IRC's) in the normal human thymus, we investigated the possible presence of these cells in human thymomas. By the unlabelled antibody PAP method, using an anti-S-100 antiserum, both by light and electron microscopy we were able to demonstrate immunolabelled IRC's in the majority of spindle cell and in some round-oval cell thymomas. Keeping in mind the possible role of IRC's in intrathymic T-cell differentiation, the present findings could be relevant in the better comprehension of this thymic neoplasm.

Histocytochemistry↗
PubMed1984

Immunohistochemical detection of folliculo-stellate cells in human pituitary adenomas.

In the light of recent findings concerning the presence of S-100 antigen in folliculo-stellate cells of the rat adenohypophysis, we investigated the possible presence of S-100-labelled cells in both the normal human adenohypophysis and in pituitary adenomas. Immunostaining enabled us to detect, with both light and electron microscopy, the presence of S-100-labelled folliculo-stellate cells in a significant number of pituitary adenomas, mostly growth-hormone secreting, and, as expected, in the normal human adenohypophysis.

Adenoma↗
PubMed1984

Increase of S-100 immunoreactivity in the urinary bladder from patients with multiple sclerosis, an indication of peripheral neuronal lesion.

The Schwann cells in urinary bladder biopsies from multiple sclerosis patients and controls were examined by immunocytochemistry with an antiserum to S-100. S-100 immunoreactivity was found to be markedly increased in these tissues as compared with the controls, indicating a Schwann cell hyperplasia in the urinary bladder in multiple sclerosis. This finding suggests that local neuronal damage exists in the urinary bladder of patients with multiple sclerosis. Therefore, the concept of multiple sclerosis as a disease wholly of the central nervous system should be reexamined.

Animals↗
PubMed1984

Detection of S-100 labelled cells in nasopharyngeal carcinoma.

S-100 antigen containing cells with dendritic features, recognisable by morphological and immunohistochemical criteria as belonging to the Langerhans' or interdigitating reticulum cell type, have been found in undifferentiated nasopharyngeal carcinoma. The presence of these cells, which have a special function of antigen presentation in immune responses, may be involved in a possible modulation of nasopharyngeal carcinoma associated Epstein-Barr virus infection and host-tumour interactions.

Carcinoma↗
PubMed1984

Acidrine in the management of gastritis and duodenitis. A double-blind placebo controlled clinical trial.

Thirty-nine adult out-patients with dyspepsia and endoscopically proven gastritis and/or duodenitis without ulcer, completed a double-blind, placebo controlled, 8-week clinical trial of either Acidrine (twenty-one patients) or placebo (eighteen patients), at a daily dosage of 2 tablets t.i.d. Treatment with Acidrine resulted in a significant improvement in symptoms and in the endoscopic appearance of the gastritis and duodenitis when compared with placebo.

Adult↗
PubMed1983

Immunochemical and immunocytochemical study of S-100 protein in rat adipocytes.

S-100 is a protein originally believed to be unique to the nervous system. We report here on the presence of S-100 in rat adipocytes, using immunohistochemical and immunochemical methods. We demonstrate that the protein in adipose tissue is present at a concentration comparable to that measured in the nervous tissue and is immunologically identical to brain S-100, indicating that the protein can no longer be regarded as being specific to the nervous system.

Adipose Tissue↗
PubMed1983

S-100 protein in "follicular dendritic" cells or rat lymphoid organs. An immunochemical and immunocytochemical study.

The presence as well as the cellular and subcellular distribution of S-100 protein were investigated in lymphoid organs of the adult rat by quantitative microcomplement fixation assay and by the immunocytochemical PAP method at the ultrastructural level. The protein appeared to be confined to the "follicular dendritic" cells both in the lymph node and the spleen, which are known to be exclusively associated with B lymphocytes in secondary follicles. The present data show an additional location for S-100 outside the nervous system. The protein may also be a useful tool to provide information on the origin and function of "follicular dendritic" cells, which are still poorly understood.

Animals↗
PubMed1983

The value of S-100 immunostaining as a diagnostic tool in human malignant melanomas. A comparative study using S-100 and neuron-specific enolase antibodies.

The brain proteins S-100 and neuron-specific enolase have been reported by separate groups to be present in human malignant melanomas. There is no systematic study comparing the occurrence of these proteins in the same tumour specimens. We have examined 33 primary malignant melanomas, including 5 which were amelanotic, and 25 metastatic melanomas using immunohistochemical methods with specific, non-cross-reacting antibodies to S-100 and NSE. We found S-100 immunoreactivity to be present in all cases but one, whereas NSE immunoreaction was very weak and patchy, and present in only 6 cases. S-100 immunoreactivity was not demonstrated in 40 control tumours, either primary or metastatic in skin, including basal- and squamous-cell carcinomas, spindle-cell sarcomas, lymphomas and Merkel cell tumours. All intradermal (n = 4) and compound (n = 1) naevi were positive for S-100, 2 blue naevi showing much less reaction. NSE immunoreactivity was detected in Merkel cell tumours (n = 8), undifferentiated (n = 2) and small cell (n = 1) carcinomas, and all melanocytic naevi. It is suggested therefore that antibody to S-100 is the reagent of choice for demonstration of melanocytic tumours, and may be especially valuable in the diagnosis of amelanotic melanoma or metastatic tumours of doubtful origin where melanoma is suspected.

Fluorescent Antibody Technique↗
PubMed1983

S-100 antigen labels neoplastic cells in liposarcoma and cartilaginous tumours.

S-100 antigen, originally believed to be unique to the nervous system, has recently been found in cell types of non-neuroectodermal origin such as chondrocytes and adipocytes. These findings suggested the possibility of detecting the antigen in tumours derived from such cells. Using the PAP method and an anti-ox brain S-100, the antigen was found in the cells of human chondrosarcomas, chondroblastomas and liposarcomas. In contrast, fibrous histiocytomas and fibrosarcomas, tested to verify the cellular specificity of the S-100 immunoreaction, did not exhibit S-100-containing cell types. The present data indicate the usefulness of the S-100 antigen as a diagnostic and investigative tool in defined neoplasms of non-neuroectodermal origin, such as chondroid tumours and liposarcoma.

Biopsy↗
PubMed1983

Neurone-specific enolase and S-100: new markers for delineating the innervation of the respiratory tract in man and other mammals.

Lung innervation has been studied in the past by methylene blue staining and silver impregnation and more recently by histochemical methods. These techniques give only a partial picture of the total innervation. We have delineated the innervation of the lung in man and three other mammalian species by immunostaining with antibodies to two new markers of nervous tissue. These markers are neurone-specific enolase (NSE), an enzyme present in nerve cells in both the central and the peripheral nervous systems, and S-100, a protein found in glial cells. Throughout the respiratory tract NSE was localised in ganglion cells and nerve fibres in all species examined, while S-100 was found in the supporting glial cells of ganglia and in Schwann cells of peripheral nerves. The distribution of NSE immunoreactivity in serial sections was compared with that of acetylcholinesterase-containing, noradrenergic, and peptide-containing nerves. In all areas NSE was found to be a specific marker for all three types of nerves. Thus these two antibodies provide an effective histological means of examining both the neuronal and the non-neuronal components of the lung innervation and should be of value in investigating this system in lung disease.

Acetylcholinesterase↗
PubMed1983

Localization of S-100 protein in Müller cells of the retina--1. Light microscopical immunocytochemistry.

S-100 is an acidic brain protein previously found to be present in glial cells of the brain and the nervous system of gut and respiratory tract. Immunocytochemistry at the light microscopical level localized immunoreactivity for S-100 in the Müller cells in the retina of rat, guinea pig, and Chinese hamster. The Müller cells represent the main glial component of the retina, with a structural role in the support and insulation of neurons and sensory elements. The use of S-100 protein as an immunocytochemical marker of Müller cells may be useful in the study of pathologic conditions of the retina where glial cell proliferation could reflect the index of neuronal injury.

Animals↗
PubMed1983

Localization of S-100 protein in Müller cells of the retina--2. Electron microscopical immunocytochemistry.

The cellular and subcellular distribution of S-100 protein was investigated at the ultrastructural level in the rat retina by the immunocytochemical PAP method. S-100 appeared to be localized in the cytoplasm and nucleus of Müller cells, offering conclusive evidence that in the mammalian retina, the protein is confined to glial cells. S-100, as a marker for Müller cells, may be a useful tool in order to study the cytoarchitecture of the retina in normal as well as in pathologic conditions. In addition, the retina may represent a suitable model for further investigation on the biologic role of S-100.

Animals↗
PubMed1982

S-100-like immunoreactivity in a planarian. An immunochemical and immunocytochemical study.

The presence of an S-100-like immunoreactivity was investigated in the planarian Dugesia gonocephala. By microcomplement fixation assay, measurable amounts of S-100-like immunoreactive material (0.11 microgram/mg soluble protein) were detected in planarian high-speed supernatants. The index of immunological dissimilarity between ox S-100 and planarian S-100-like immunoreactive material was higher than that previously calculated between ox S-100 and all the vertebrates tested. By the immunohistochemical PAP method, S-100-like immunoreactivity was only detectable in the cilia of the epidermal cells. Although the biological meaning of S-100-like immunoreactivity in planarian remains to be clarified, the present data introduce new perspectives into the investigation of S-100.

Animals↗
PubMed1981

S-100 antigen in satellite cells of the adrenal medulla and the superior cervical ganglion of the rat. An immunochemical and immunocytochemical study.

Measurable amounts of the nervous-system specific S-100 protein were detected by microcomplement fixation assay both in the superior cervical ganglion and in the adrenal medulla of adult rats, though at a significantly higher concentration in the ganglion. By the unlabeled antibody PAP method, the antigen was localized at the ultrastructural level in the Schwann cells and in the satellite cells of the ganglion, but not in neurons. Similarly, the protein was found in the Schwann cells of the adrenal medulla, but not in the chromaffin cells. Moreover, the S-100 immunolabeling allowed detection of a class of "satellite" cells closely enveloping the chromaffin cells. In the labeled cells of both organs the reaction product was diffusely distributed in the cytoplasmic matrix as well as in the nucleoplasm. The presence of the S-100 antigen in the satellite cells of the sympathetic ganglion and in "satellite" cells of the adrenal medulla suggests a possible homology for the two cell types, and one could hypothesize the presence in peptide hormone-secreting endocrine organs of glia-like cells exhibiting functional relationships with the secretory cells comparable to those of the glial cells with the neurons.

Adrenal Medulla↗
PubMed1981

S-100 protein in the brain of hypothyroid adult rats: an immunochemical and immunocytochemical study.

The levels and the distribution of S-100 protein were studied in the brain of hypothyroid adult rats. The concentration of the protein was significantly increased in the soluble fraction of hypothyroid rat brain as compared with controls (P less than 0.001). This finding probably reflects the increased number of astroglial cells, which has been widely reported in hypothyroid adult rats. The immunocytochemical ultrastructural distribution of the protein in the cerebellar cortex was not affected by thyroid deficiency. The protein was thus confined to the cytoplasm and the nucleus of the astroglial cells both in treated and untreated rats.

Animals↗
PubMed1981

Specific binding sites for S-100 protein in isolated brain nuclei.

Isolated brain nuclei possess binding sites for S-100 protein. The interaction of S-100 with these sites is specific and time-, temperature-, and Ca+ -dependent. The profile of the (125)I-labelled S-100 binding inhibition is biphasic, displaying a high-affinity component and a low-affinity component. The S-100 binding to brain nuclei is largely irreversible, probably owing to the formation of a tight complex between the protein and its nuclear binding sites. The S-100 binding to brain nuclei is in most aspects similar to that to synaptosomal membranes. Several lines of evidence indicate, however, that the S-100 binding to nuclei is not due to contamination of these structures with plasma membranes. Isolated liver nuclei do not possess the high-affinity component of S-100 binding.

Animals↗