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F Michetti

Publications and source records attributed to F Michetti.

70 records · Page 4Linked to original sources
PubMed1981

Subnuclear distribution of the S-100 protein specific binding sites in rat brain.

Fractionation of isolated brain nuclei previously reacted with (125)I-labelled S-100 showed that most of the specifically bound radioactivity associated with the nuclear membranes and the nucleoli. Labelling of nucleoli, which indicates the entrance of (125)I-labelled S-100 into the nucleus, was observed at 37 percent C, but not at 0-4 percent C. When tested separately for (125)I-labelled S-100 specific binding, both the nuclear membranes and the nucleoli were found to bind (125)I-labelled S-100 in a biphasic manner, the binding displaying a high affinity and a low affinity component, as observed with intact nuclei. However, the binding to nuclear membranes was largely irreversible, while that to nucleoli was fully reversible after any association time.

Animals↗
PubMed1980

Antigenic properties of the loosely bound subnuclear fraction of rat brain.

Antibodies against the loosely bound subnuclear fraction (0.35 M NaCl-extractable subnuclear fraction) of rat brain were raised in rabbits, and the distribution of the main antigenic determinants was followed among subcellular fractions of nervous tissue and among homologous nuclear preparations from different tissues. By immunofluorescence a localization restricted to the nucleus was observed, and by microcomplement fixation the antigens appeared to specifically enrich the fraction under examination, being poorly detectable in cytosol, nuclear sap, or deoxyribonucleoproteins of rat brain. No significant cross-reaction was observed by complement fixation with homologous preparations from muscle, liver, kidney, spleen, lung, or thymus of rat, whereas the 0.35 M NaCl-extracted subnuclear fraction from rat testis exhibited an immunoreactivity, although lower than that for brain proteins. After trypsin or ribonuclease treatment, the main antigenic determinants appeared to be protein in nature. The subnuclear fraction under examination, which is believed to be relevant to gene regulation, appears to contain protein antigens mainly concentrated in the nervous system.

Animals↗
PubMed1980

The S-100 antigen in cerebrospinal fluid as a possible index of cell injury in the nervous system.

The presence of the nervous system-specific S-100 antigen has been tested by microcomplement fixation assay with a monospecific anti-S-100 antiserum in cerebrospinal fluid (CSF) of subjects suffering from psychiatric disorders or various neurological diseases. The antigen was detectable in the CSF of most of the patients with neurological diseases characterized by an appreciable lesion in the nervous parenchyma, whereas it was generally absent from CSF of subjects presumably free from an extensive neurological lesion in the active phase. It is possible that the presence of S-100 IN CSF might be an index of active cell injury in the nervous parenchyma.

Adolescent↗
PubMed1980

Localization of the loosely bound nuclear proteins of rat brain: an immunocytochemical ultrastructural study.

Antibodies against the loosely bound subnuclear protein fraction (0.35 M NaCl-extractable subnuclear fraction) of rat brain were raised in rabbits, and the ultrastructural distribution of the antigenic determinants in rat cerebellum was studied using the unlabeled antibody peroxidase-antiperoxidase (PAP) method. A localization restricted to the nucleus was observed. Both neuronal and neuroglial nuclei exhibited antigens, whereas nuclei of pericytes and endothelial cells did not. The immunoreaction product was homogeneously distributed in dispersed chromatin and was absent from condensed chromatin, suggesting that the antigens were confined to the active regions of the genoma. The outer nuclear membrane and the nucleolus appeared to be free of the antigens, while a perinucleolar ring of immunoreaction was detectable. Liver preparations showed a nuclear reaction markedly weaker than the one for brain nuclei. Adsorption of the serum with isolated liver nuclei nullified the reactivity in liver tissue, whereas a sharp reaction was still observed in the cerebellum, indicating the subcellular reaction under examination to contain antigens specifically concentrated in the nervous system or unique to the brain.

Animals↗
PubMed1979

The nervous system-specific S-100 antigen in cerebrospinal fluid of multiple sclerosis patients.

The nervous system-specific S-100 antigen has been found in cerebrospinal fluid (CSF) of 13 out of 18 patients with multiple sclerosis (MS), whereas it was undetectable in either of the 11 control patients with minor psychic disturbances or with neurological disorders not usually associated with apparent parenchymal lesion. The levels of the antigen appeared to be higher in CSF of patients in the acute phase of the disease. Though the small number of cases hampers final statements, the S-100 in CSF might serve as a possible index of active cell injury in the central nervous system underlying the pathogenesis of MS.

Cerebrospinal Fluid Proteins↗
PubMed1975

Soluble and membrane-bound S-100 protein in cerebral cortex synaptosomes. Properties of the S-100 receptor.

Within cerebral cortex synaptosomes, S-100 protein can be recovered in two forms: soluble and membrane-bound. Synaptosomal S-100 is mainly a soluble protein (85 percent). The membrane-bound S-100 is differently distributed in the synaptosomal membranes, intraterminal mitochondria, and synaptic vesicles. S-100 binds to a specific receptor. The binding is time-dependent, reversible and saturable with respect to S-100. The number of receptors is calculated to be about 9 times 10(12)/mg protein, since saturation is achieved at 31 ng [125I]S-100/0.1 mg protein of disrupted synaptosomes. The rate constant for association of S-100 with its receptor at 37 degrees C, k1, is 4.74 times 10(4) M(-1) sec(-1), and the rate constant for dissociation, k-1, 9.24 times 10(-4) sec(-1).

Animals↗
PubMedDate not supplied

S-100 proteins in trimethyltin-induced neurodegeneration in the rat hippocampus. An immunochemical and immunocytochemical study.

After acute trimethyltin (TMT) intoxication (21 d after a single i.p. injection at a dose of 8 mg/kg) the histological, immunohistochemical, and immunochemical investigation of adult rat hippocampus showed a distinct pattern of neuronal loss, and an increase in both glial fibrillary acidic protein- (GFAP) immunoreactive cells and GFAP concentration, as expected. S-100-immunoreactive cells also increased markedly, whereas the concentration of S-100 increased even more than that of GFAP. The data show that S-100 is an index of glial reaction to damage after TMT intoxication and suggest the potential usefulness of exploring the possibility that it may play a role in induced neurodegenerative processes.

Animals↗
PubMedDate not supplied

Improvement of mortality rate and decrease in histologic hepatic injury after human cord blood stem cell infusion in a murine model of hepatotoxicity.

BACKGROUND AND AIMS: Because of their plasticity potential local and systemic application of cord blood stem cells may represent excellent candidates for cell-based therapeutic strategies in toxic liver injuries. It is already known that intraperitoneal administration of hematopoietic stem cells provides rapid liver homing in animal models of hepatic injury. We sought to assess the efficacy of a hematopoietic stem cell infusion to decrease the histologic damage and the mortality rate of animals previously damaged by allyl alcohol. MATERIAL AND METHODS: NOD/SCID mice were divided into two groups. (1) animals treated by intraperitoneal administration of allyl alcohol and (2) animals treated with allyl alcohol and 24 hours later with an intraperitoneal infusion of human cord blood cells. Flow cytometry, histology, immunohistochemistry, and RT-PCR were performed to monitor human cell engraftment by evidences of human hepatic markers. RESULTS: Human stem cells were able to transdifferentiate into hepatocytes, improve liver regeneration after damage, and reduce the mortality rate even when requiring qualitative and quantitative differences in the transdifferentiation processes. The mortality rate decreased from 70% to 20%, with a significant improvement in the histologic findings. CONCLUSION: We demonstrated that the infusion of hematopoietic stem cells into the liver in the early stage of damage might initiate endogenous hepatic tissue regeneration that oppose the injury inflicted by toxicants.

Animals↗
PubMedDate not supplied

Human cordonal stem cell intraperitoneal injection can represent a rescue therapy after an acute hepatic damage in immunocompetent rats.

BACKGROUND AND AIM: Tissue homeostasis and turnover require reserve stem proliferating cells. Several studies performed on immunodeficient animals have suggested a degree of plasticity by the hematopoietic stem cell compartment that may represent source for liver regeneration. We sought to explore the hepatic differentiation potential of hematopoietic stem cells from human cord blood, after toxic liver damage induced by allyl-alcohol in immunocompetent rats. MATERIALS AND METHODS: Wistar rats were divided into groups (A) allyl-alcohol intraperitoneal injection with hematopoietic stem cell intraperitoneal infusion at 1 day and sacrifice 3 days later; (B) stem cell injection and sacrifice 3 days later; (C) allyl-alcohol infusion and sacrifice 4 days later; and (D) sacrifice without any treatment. Livers, spleens, and bone marrows were analysed for human stem cells using flow-cytometry; livers were also tested by histology and immunohistochemistry to study the pattern of hepatic regeneration after damage and human stem cell conversion into hepatocyte-like cells, respectively. RESULTS: Flow-cytometry revealed selective recruitment of human hematopoietic stem cells by damaged livers (group A) compared with control group B. In addition, liver damage was reduced in animals treated with stem cells. Immunohistochemistry demonstrated that human stem cells could convert hepatic cells. CONCLUSIONS: Our study demonstrated that hematopoietic stem cells selectively recruited by injured livers can contribute to hepatic regeneration after acute toxic damage in immunocompetent recipients.

Animals↗