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Biomedical subjects

F Michetti

Publications and source records attributed to F Michetti.

At least 37 records · Page 2Linked to original sources
PubMed1994

Intravariceal pressure measurement in cirrhotic patients: is it a reliable technique?

The aim of the present study is to evaluate in both "in vitro" and clinical conditions the reliability of the method for measuring the oesophageal varices pressure by means of a sclerosing needle. The perfusion system was validated "in vitro", comparing the tracings obtained with two different perfusion apparatus, with two different perfusional agents and with the needle either completely or partially inserted in a venous catheter perfused with saline solution, either in the same direction as the flow or the opposite one. The clinical validation was conducted on 14 cirrhotic patients with II to IV grade oesophageal varices according to Dagradi's classification. During endoscopy, the intravariceal and oesophageal pressures were measured using a sclerosing needle, perfused with hydrosoluble contrast medium. Once the intravariceal pressure measurement was completed, an X-ray film of the chest was performed. The data were evaluated considering the absence of visible contrast medium as evidence of correct intravariceal needle position, and the presence of a roundish image as evidence of paravariceal insertion of the needle. The presence of respiratory oscillations and intravariceal pressure values were verified in manometric tracings and were compared with radiological findings. The "in vitro" tests showed no differences in the pressure recording obtained using different pumps, different perfusion agents and with different manners of inserting the needle. Only twenty-eight of the manometric recordings were considered adequate for evaluation in clinical conditions.(ABSTRACT TRUNCATED AT 250 WORDS)

Esophageal and Gastric Varices↗
PubMed1993

S-100 protein in rat brown adipose tissue under different functional conditions: a morphological, immunocytochemical, and immunochemical study.

The brown adipose tissue (BAT) is responsible for nonshivering thermogenesis, exhibiting changes in cell morphology related to the functional conditions. In stimulated BAT (neonatal period, cold acclimation) the large majority of adipocytes become multilocular and active, while in inactive BAT (warm acclimation) most cells are pauci- or unilocular and inactive, very similar to white adipocytes. It is well known that white adipocytes are sites of concentration of S-100, a calcium-binding protein originally isolated from the nervous system and later detected also in nonneural cell types, whereas data on the possible presence of this protein in BAT are lacking. The present study used morphological, immunocytochemical, and immunochemical methods to investigate the presence of S-100 protein in BAT under different functional conditions. We found that S-100 was present in both stimulated and inactive BAT and that is was expressed in significantly higher quantities in the latter than in the former. The multilocular cells were always negative (in both active and inactive tissue), whereas the pauci- and unilocular cells were always S-100-positive under both functional conditions. These data suggest that only pauci- and unilocular brown adipocytes express S-100 protein, thus manifesting a possible relationship between S-100 and cell morphology.

Adipose Tissue, Brown↗
PubMed1992

Immunochemical and immunohistochemical detection of S-100-like immunoreactivity in spinach tissues.

S-100 proteins represent a group of closely related acidic, calcium binding proteins originally isolated from the mammalian nervous system and later detected in non-neural cell types and in a wide variety of vertebrate and invertebrate species. The present study used immunochemical and immunohistochemical methods to extend the investigation of S-100 during phylogenesis to plant tissues. The presence of S-100-like immunoreactive material was detected in extracts of spinach (Spinacia oleracea L.) terminal buds and young leaves by the ELISA method and by Western blotting using different anti-S-100 rabbit antisera. Using the PAP method, serial sections of young spinach leaves treated with the same antisera exhibited an immunoreaction product that was confined to the cytoplasm and nucleus (but absent from the vacuoles) in meristematic, epidermal, and parenchymal cells. The present data enlarge the field of investigation of S-100 proteins in the search of the function(s) of S-100 in biological organisms.

Animals↗
PubMed1992

Relationship patterns in "folie à deux".

"Folie à deux" is characterized by the communication of delusional ideas from one subject to other ones who have been living closely with him for a long time, usually his relatives. Before illness shows, there is a leader-follower relationship between partners, who are lacking of external sources of pleasure and are socially or culturally isolated. The dominating partner usually is a paranoic subject who strongly needs his ideas to be accepted by other people, while the dominated partner is a dependent subject who shares the other one's ideas in order to get pleasure from him and who is not able to criticize these ideas because of the lack for external influences. The two partners project hostility into the external world because, if the dominated partner does not share the other one's ideas, hostility will be projected into him and he will become very anxious. Interpersonal mechanisms in "folie à deux" are similar to those which take place in brainwashing, hypnosis and psychotherapy.

Humans↗
PubMed1990

Immunocytochemical distribution of S-100 protein in patients with Down's syndrome.

The immunohistochemical distribution of S-100 beta protein in patients with Down's syndrome was investigated as part of a study aimed at ascertaining a possible involvement in the syndrome (trisomy 21) of this protein, which has recently been shown to be coded in chromosome 21. No appreciable differences in the cell distribution of the antigen could be observed between patients with Down's syndrome and normal subjects. The possibility of an overexpression or abnormal expression of the molecule as a consequence of chromosome 21 triplication, not detectable by immunocytochemical methods alone, remains to be investigated.

Child, Preschool↗
PubMed1989

Satellite cells in developing spinal ganglia. An immunohistochemical study.

The present immunohistochemical study investigates the presence and distribution of S-100-containing glial cells in the early stages of development in human spinal ganglia. From the earliest ages investigated immunoreactive cells could be detected in a continuous layer at the periphery as well as inside ganglionic rudiments in close relationship with neural elements, both at the light and ultrastructural levels. The possibility that these glial cells, exhibiting such a distinctive distribution, play a modulatory role on microenvironmental influences during maturation could be taken into account. Neither glial fibrillary acidic protein nor myelin basic protein could be detected at the ages investigated.

Embryonic and Fetal Development↗
PubMed1987

Comparative study by S-100 and GFAP immunohistochemistry of glial cell populations in the early stages of human spinal cord development.

The present study reports the presence and distribution of S-100-containing cells in the developing human spinal cord. From the earliest stages investigated, S-100-immunostained cells bordered the ventral third of the central canal or appeared dispersed in the basal lamina. On the other hand, radial glia processes were clearly depicted after GFAP immunolabelling. The presence and peculiar distribution of S-100-immunoreactive cells could be significant in the study of the early events of glial differentiation and migration.

Glial Fibrillary Acidic Protein↗
PubMed1986

Glial-like cells in sympathetic neural crest derivatives during human embryogenesis. Detection by S-100 immunohistochemistry.

The present study investigates at the light and electron microscopic levels the possible presence and distribution during human development of glial-like satellite cells in sympathetic neural crest derivatives by S-100 immunohistochemistry. From the earliest stages investigated, immunostained cells were detected inside sympathetic migrating masses and at their periphery, where they constituted a continuous layer isolating sympathetic elements from mesenchymal cells. The detection and peculiar distribution of these glial-like cells in developing sympathetic tissue could open new perspectives in the study of events linked to the migration and differentiation of some neural crest derivatives.

Cell Differentiation↗
PubMed1986

Immunohistochemical localization of S-100-containing cells in non-nervous structures of the human eye.

The present study reports on the immunohistochemical distribution of S-100 antigen in non-nervous cell types within the human eye at light microscopy. In the cornea the antigen was confined to endothelial cells covering its posterior surface; the lens exhibited immunoreactivity restricted to the epithelial cells located beneath the anterior capsule. In the iris and ciliary body, S-100 was detected in stromal cells and epithelial cells of the pigmented inner layer in the former and inner epithelial cells bounding the posterior chamber in the latter.

Ciliary Body↗
PubMed1985

S-100 protein in the testis. An immunochemical and immunohistochemical study.

S-100, a protein originally believed to be unique to the nervous system, has recently been found in extraneural presence of S-100 in the testis, namely in Leydig cells and in lymphatic endothelial cells, using immunohistochemical and immunochemical methods. We show that the protein in the testis is immunologically identical to brain S-100. The S-100-labelled cells in the testis exhibit morphological similarities with other cell types in different tissues known to contain S-100.

Animals↗
PubMed1985

Myelin basic protein and S-100 antigen in cerebrospinal fluid of patients with multiple sclerosis in the acute phase.

It has previously been demonstrated that both Myelin Basic Protein (MBP) and S-100 are released in the cerebrospinal fluid (CSF) of multiple sclerosis (MS) patients during acute phases of exacerbation of the disease. In order to investigate the pathobiological significance of the release of these two proteins into the CSF, MBP and S-100 were assayed in 10 MS patients during the five weeks following onset of an acute exacerbation. MBP was detectable in CSF during the first three weeks after exacerbation, while S-100 was detectable during the entire period of observation, at least in some of the patients. MBP reached its highest CSF concentrations during the first two weeks while S-100 did so in the third week, decreasing thereafter. This difference in time of presence of MBP and S-100 in the CSF is probably due to the different biological origin, MBP being a marker of myelin sheath injury, and S-100, more probably, of astrocytic activity.

Adolescent↗
PubMed1985

Satellite cells in the normal human adrenal gland and in pheochromocytomas. An immunohistochemical study.

In light of the recent finding of the S-100 antigen in satellite cells of the rat adrenal medulla, we looked for S-100-labelled cells in both the normal human adrenal medulla and in pheochromocytomas. Immunostaining enabled us to detect S-100-labelled satellite cells by both light and electron microscopy in a significant number of pheochromocytomas and, as expected, in the normal human adrenal medulla.

Adrenal Gland Neoplasms↗
PubMed1985

Immunohistochemical distribution of S-100 antigen in the urinary system of man and rat.

The immunohistochemical distribution of S-100, a protein originally isolated from the brain, has been investigated at the light and electron microscopic levels in rat and man urinary systems. In both species the antigen essentially exhibited the same location, restricted, with different degrees of staining, to certain cells in the kidney, i.e. collecting tubules, thin limbs of Henle's loop and renal papillae.

Animals↗
PubMed1984

Neuronal and glial markers in tumours of neuroblastic origin.

The presence and distribution of different neural markers in 30 neuroblastic tumours (neuroblastomas, ganglioneuroblastomas) and 6 non-neuroblastic tumours were investigated by immunocytochemistry. Neuron-specific enolase (NSE), S-100 protein, tyrosine hydroxylase, neurofilaments and glial fibrillary acidic protein (GFAP) were localised in 3 undifferentiated neuroblastic tumours (group A), 12 poorly differentiated tumours (group B) and 15 well differentiated neuroblastic tumours (group C). Non-neuroblastic tumours (3 lymphomas and 3 Ewing sarcomas) showed no immunoreactivity. Tyrosine hydroxylase and, in particular, NSE were found in mature ganglion cells and developing neuroblasts of poorly and well differentiated tumours (groups B and C). S-100 was localised in neuroblasts with slender cytoplasmic processes in the same groups. Neurofilaments were detected in ganglion cells and differentiated neuroblasts (groups B and C) while GFAP was localised in immature neuroblasts of undifferentiated and poorly differentiated tumours (groups A and B). Thus, there are differences in the neural proteins found in neuroblastic tumours and a wide panel of antibodies against neural markers may be a useful tool in the histological assessment of nervous system neoplasms.

Adolescent↗
PubMed1984

Immunocytochemistry of neuronal and glial markers in retinoblastoma.

An immunocytochemical study of 30 retinoblastomas was carried out using antibodies to neuronal and glial markers. The tumours were found to react with antibodies to neuron-specific enolase (NSE), a marker for neuronal elements, and S-100 and glial fibrillary acidic protein (GFAP), both of which are proteins present in glia. Two distinct cell populations were found within the tumour: the first, composed of anaplastic tumour cells at various stages of differentiation, showed both NSE and S-100 immunoreactivity; the second cell type, which immuno-stained for S-100 and GFAP, resembled mature glial cells. The results of this study indicate that the retinoblastoma may arise from a pluripotential primitive cell partially retaining neuronal and glial characteristics.

Eye Neoplasms↗