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M Pocchiari

Publications and source records attributed to M Pocchiari.

At least 55 records · Page 3Linked to original sources
PubMed1995

Congo red prolongs the incubation period in scrapie-infected hamsters.

In scrapie-infected cells, Congo red inhibits both the replication of the infectious agent and accumulation of the protease-resistant form of PrP (PrP-res). In this report, we show that Congo red prolongs the incubation periods of hamsters experimentally infected with two different strains of scrapie.

Animals↗
PubMed1994

Polymorphisms of the prion protein gene in Italian patients with Creutzfeldt-Jakob disease.

Creutzfeldt-Jakob disease (CJD) is a transmissible neurodegenerative disorder characterized by the accumulation of the amyloid protein PrP in the CNS. Two coding polymorphisms of the PrP gene (PRNP) are a methionine (Met) to valine (Val) change at codon 129, and a deletion in the octapeptide coding region. In the United Kingdom, homozygosity at codon 129 appears to be associated with a predisposition to develop CJD. However, in Japan, where allelic frequencies and genotype distribution are significantly different, such an association has not been demonstrated. To determine whether such deletion(s) or codon 129 polymorphisms of PRNP predispose to the development of CJD in Italian patients, 31 sporadic CJD patients with no known PRNP mutations, and 186 unrelated control subjects were studied. Genotypic frequencies at codon 129 in these Italian CJD patients revealed a significant excess of methionine alleles, and a different genotype distribution in comparison with the normal Italian population. Deletions of a 24-bp segment located in the PrP octapeptide coding region were found in two control subjects, but in none of the sporadic CJD patients. These data suggest that Met homozygosity at codon 129 may contribute, with other environmental or endogenous factors, to CJD development.

Adult↗
PubMed1994

Characterisation of antisera raised against species-specific peptide sequences from scrapie-associated fibril protein and their application for post-mortem immunodiagnosis of spongiform encephalopathies.

Transmissible spongiform encephalopathies (TSE), such as scrapie or Creutzfeldt-Jakob disease (CJD), are fatal neurodegenerative diseases of the central nervous system caused by a yet unidentified virus. They are accompanied by a brain specific amyloidosis, during which a host coded protein irreversibly aggregates to form the scrapie-associated fibrils. The diagnosis of TSE relies on histopathological detection of spongiform lesions, on electron microscopical detection of fibrils, or on the immunological detection of SAF protein, which is the most specific diagnostic marker. In order to improve the diagnosis of TSE, we developed a protocol for rapid tissue fractionation and enrichment of SAF protein which subsequently allows the specific detection of SAF protein by western blotting and immunodetection. Using some new antisera raised against synthetic peptides with sequences specific for the hamster, sheep, cattle and human SAF protein, several samples can be diagnosed for TSE within 24 hours, starting with only 10-100 mg of brain tissue from different species.

Amino Acid Sequence↗
PubMed1994

Detection of proteinase-resistant protein (PrP) in small brain tissue samples from Creutzfeldt-Jakob disease patients.

We describe a short and a sensitive method to isolate PrP in small samples of brain tissue using a one day procedure. The tissue was homogenized in sarkosyl, cleared by low-speed centrifugation, and then ultracentrifuged. The pellet was suspended in 10 mM Tris-HCl, 10% NaCl, 1% sarkosyl, precipitated by centrifugation and re-suspended in the above solution with proteinase K. After digestion, PrP was spun down, electrophoresed on a 15% SDS-polyacrylamide minigel and then electro-transferred to a nitrocellulose membrane. The blots were processed with rabbit polyclonal antibody against hamster PrP27-30. Four bands of PrP with molecular weights of 28-30 kDa, 24-26 kDa, 19-20 kDa, and 16 kDa were clearly detected by Western blot in two samples obtained by brain biopsy. To test the sensitivity and the specificity of our method we also purified PrP from 20, 50 and 100 mg of cerebral cortical tissues taken from six frozen CJD brains and one Alzheimer's disease brain of our collection. All the CJD samples, but not the Alzheimer's disease one, resulted positive by Western blot. In the smallest sample tested (20 mg), there was at least one band (about 25 kDa) of PrP detectable by Western blot. Thus, this is a valid and efficient method for the diagnosis of CJD in small brain tissue samples.

Animals↗
PubMed1994

Modification of tritiated gamma-amino-n-butyric acid transport in rabies virus-infected primary cortical cultures.

The role of brain neurotransmitter transport processes in rabies virus infection of neurons was examined. The uptake and release of gamma-amino-n-butyric acid (GABA) in rabies virus-infected embryonic rat cortical neurons was assayed using tritiated ligands. A 45% reduction of [3H]GABA uptake was observed 3 days post-infection, when a maximum level of infectious particle release occurs. At this time, kinetic analysis revealed significant changes in Vmax, whereas no changes were found in Km values in comparison with the control values. K+ and veratridine-induced [3H]GABA release was increased in infected cultures (98% and 35%, respectively) as compared with control values. The results obtained from rabies virus-infected cultures provide some preliminary evidence of the involvement of GABA in the pathogenesis of rabies.

Animals↗
PubMed1994

Iatrogenic Creutzfeldt-Jakob disease: an example of the interplay between ancient genes and modern medicine.

We tested DNA from 15 centrally infected cases of iatrogenic Creutzfeldt-Jakob disease (CJD) (dura mater or corneal homografts and stereotactic EEG electrodes), 11 peripherally infected cases (native human growth hormone or gonadotrophin), and 110 control individuals for the presence of mutations in the chromosome 20 amyloid gene. No patient or control had any of the known pathogenic point or insert mutations found in familial disease, but allelic homozygosity at polymorphic codon 129 was present in all but two (92%) of the 26 patients, compared with 54 (50%) of the 110 controls (p < 0.001). Pooled data from all identified and tested cases of iatrogenic disease yielded a worldwide total of 56 patients, of whom all but four were homozygous at codon 129 (p < 0.001). These findings support the thesis that homozygosity at codon 129 enhances susceptibility to iatrogenic infections of both central and peripheral origin, with evident implications for the population of dura mater homograft and pituitary hormone recipients whose lives have been complicated by the possibility of exposure to the infectious agent of CJD.

Amyloid↗
PubMed1993

A new point mutation of the prion protein gene in Creutzfeldt-Jakob disease.

Complete sequencing of the prion protein open reading frame of a 68-year-old woman affected by a familial form of Creutzfeldt-Jakob disease (CJD) revealed a new mutation at codon 210 resulting in the substitution of isoleucine for valine. Moreover, a new 24-bp deletion encompassing codons 54 to 61 or 62 to 69 was found in the other allele. Four of the 17 asymptomatic relatives tested carry the 210 mutation. Two of them were 81 and 82 years old. Four of 22 patients with CJD whose recorded familial history was negative for demented illnesses, but none of 103 healthy control subjects, tested positive for the 210 mutation. These data suggest that the 210 mutation is associated with CJD, but that environmental factors or incomplete penetrance may contribute to the development of the disease. This finding also suggests that in Italy, familial CJD is more common than previously reported.

Aged↗
PubMed1992

Amphotericin B treatment dissociates in vivo replication of the scrapie agent from PrP accumulation.

Scrapie and related animal and human disorders are neurodegenerative diseases characterized by the formation of a modified, partly proteinase-resistant protein (PrP) of the host, which tends to aggregate as amyloid fibrils and accumulate in the brain of infected individuals. There is a general consensus that the pathological form of PrP (PrPSc) is essential for the clinical appearance of the disease, but whether it is part of the scrapie agent or a by-product of viral infection is still controversial. Here we report that treatment of scrapie-infected hamsters with amphotericin B delays the accumulation in the brain of the proteinase-resistant portion of PrPSc by about 30 days without affecting scrapie replication. The consequence is that hamsters treated with amphotericin B developed clinical signs of disease later than infected controls. We argue that the proteinase-resistant portion of PrPSc is necessary for the development of the disease but that it is unlikely to be essential for scrapie replication.

Amphotericin B↗
PubMed1992

Sulphate polyanions prolong the incubation period of scrapie-infected hamsters.

The effect of the organic sulphated polyanions, pentosan sulphate (SP54), dextran sulphate 500 (DS500) and suramin, have been tested on golden Syrian hamsters infected with the 263K strain of scrapie by the intraperitoneal (i.p.) or the intracerebral route. SP54 had the greatest effect in prolonging the incubation period of the disease when administered within 2 h of the i.p. inoculum. The same amount of SP54 given 24 h after scrapie inoculation had a potent effect in some animals and no effect in others. This result suggests that SP54 inhibits the uptake of the scrapie agent into the nerve endings and/or carrier cells at the site of the inoculum, i.e. the peritoneum, and that this event occurs in about 24 h. DS500 had a similar although less potent effect (22.4 days delay during the incubation period) than SP54 (54.4 days) when administered within 2 h of scrapie injection by the i.p. route, and suramin had only a minimal effect (10 days). This study suggests that treatment of scrapie and related spongiform encephalopathies of animals and man is possible only before the agent has reached the clinical target areas of the brain.

Animals↗
PubMed1992

Bovine spongiform encephalopathy: an overview.

Bovine spongiform encephalopathy (BSE), a novel disease of cattle first described in 1986, has now reached epidemic proportion in Great Britain with about 500 cases a week. The clinical, epidemiological, and pathological characteristics of BSE are described. Moreover, the etiopathogenetic mechanisms of spongiform encephalopathies are reviewed. Legislative measures to prevent the spread of BSE in Italy and in other EEC countries and to minimize the theoretical risk to man are reported.

Animals↗