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S Piacentini

Publications and source records attributed to S Piacentini.

At least 37 records · Page 2Linked to original sources
PubMed1997

Presenilin-1 gene intronic polymorphism in sporadic and familial Alzheimer's disease.

A recent observation has shown a genetic association between an intronic polymorphism in the Presenilin-1 (PS-1) gene and late onset Alzheimer's disease (AD). The homozygosity of the 1 allele in the PS-1 gene was associated with a doubling of the risk for late onset AD. However, contrasting results have been published. We analyzed the distribution of the PS-1 intronic polymorphism in patients with sporadic AD and in seven familial AD (FAD) families carrying pathogenetic mutations in the amyloid precursor protein (APP) and Presenilin (PS-1 and PS-2) genes. Significant differences in PS-1 allele frequencies were observed in the Presenilin genes mutated families but not in late onset AD patients and in APP mutated families.

Adult↗
PubMed1996

Alzheimer's disease and apolipoprotein E in Italy.

Recent studies have provided evidence of association of apolipoprotein E (ApoE) epsilon 4 allele and late onset familial and sporadic Alzheimer's disease (AD). Epidemiological studies have established allelic variation at the ApoE locus. We have analyzed the ApoE gene polymorphism in a sample of 416 Italian subjects. Our data confirm a significant association between epsilon 4 allele and sporadic AD. The frequency of epsilon 4 allele in early onset familial AD patients was comparable to control values suggesting that epsilon 4 allele does not represent a risk factor for early onset familial AD (EOFAD). Moreover, we found a not-previously reported association between ApoE epsilon 2 allele and sporadic AD and EOFAD. We included in this study two EOFAD families with the APP717 Val-->Ile mutation in the Amyloid Precursor Protein (APP) gene on chromosome 21. In any of the EOFAD families there was a significant effect of the ApoE genotype on the age of onset with the exception of one of the two mutated EOFAD families in which the 2 allele delays the age of onset.

Adult↗
PubMed1996

Apolipoprotein E and alpha1-antichymotrypsin polymorphism in Alzheimer's disease.

A recent observation has shown that a common polymorphism in the alpha1-antichymotrypsin (ACT) gene modifies the apolipoprotein E (ApoE) epsilon4-associated Alzheimer's disease (AD) risk identifying the combination of the ACT/AA and ApoE epsilon4/epsilon4 genotypes as a potential susceptibility marker for AD. We analyzed the segregation of the ApoE and ACT polymorphism in sporadic and familial AD patients. In none of the sporadic AD patients did we find the combination of the ACT/AA and ApoE epsilon4/epsilon4 genotypes. The frequency of ApoE epsilon4/epsilon4 homozygosity in the AD sample resulted highest for the ACT/ TT genotype (17.6%). Our data fail to confirm any additional association with AD beyond the ApoE epsilon4 allele with any ACT genotype, suggesting that ACT does not represent an additional risk factor for AD.

Adult↗
PubMed1996

Perceptual and premotor components of unilateral auditory neglect.

Recent investigations have distinguished between ophthalmokinetic and melokinetic factors of unilateral neglect. The aim of our study was to investigate the possible dissociation between melokinetic (premotor) and perceptual factors, avoiding any overt oculokinetic components. We asked four blindfolded left neglect patients to set a dichotic sound in central position, by moving a handle controlling the difference of intensity between the sounds delivered to the left and to the right ears. Two conflicting conditions were used. In the congruent condition, the sound moved in the same direction as the hand movement; in the noncongruent condition, it moved in the opposite direction. One patient performed as if suffering from melokinetic neglect, and another as if suffering from perceptual neglect. The behavior of the other two subjects did not lend itself to a clearcut interpretation.

Aged↗
PubMed1996

Alzheimer's disease associated with mutations in presenilin 2 is rare and variably penetrant.

Missense mutations in the presenilin 2 (PS-2) gene on chromosome 1 were sought by direct nucleotide sequence analysis of the open reading frame of 60 pedigrees with familial Alzheimer's disease (FAD). In the majority of these pedigrees, PS-1 and beta-amyloid precursor protein (beta APP) gene mutations had been excluded. While no additional PS-2 pathogenic mutations were detected, four silent nucleotide substitutions and alternative splicing of nucleotides 1338-1340 (Glu325) were observed. Analysis of additional members of a pedigree known to segregate a Met239Val mutation in PS-2 revealed that the age of onset of symptoms is highly variable (range 45-88 years). This variability is not attributable to differences in ApoE genotypes. These results suggest (i) that, in contrast to mutations in PS-1, mutations in PS-2 are a relatively rare cause of FAD; (ii) that other genetic or environmental factor modify the AD phenotype associated with PS-2 mutations; and (iii) that still other FAD susceptibility genes remain to be identified.

Age of Onset↗
PubMed1995

ApoE genotype and familial Alzheimer's disease: a possible influence on age of onset in APP717 Val-->Ile mutated families.

Recent studies have shown a genetic association of the apolipoprotein E (ApoE) epsilon 4 allele with late onset familial and sporadic Alzheimer's disease (AD). In this study we analysed the possible association of the genetic polymorphism of the ApoE gene with age of onset in Italian familial Alzheimer's disease (FAD) families including two early onset familial Alzheimer's (EOFAD) families with the APP717 Val-->Ile mutation in the amyloid precursor protein (APP) gene on chromosome 21. In none of the FAD families analysed was there a significant effect of the ApoE genotype on the age of onset with the exception of one of the two mutated EOFAD families in which the epsilon 2 allele delayed the age of onset.

Age Factors↗
PubMed1995

Epistatic effect of APP717 mutation and apolipoprotein E genotype in familial Alzheimer's disease.

We found a new familial Alzheimer's disease kindred in which the disease cosegregates with the APP717Val-->Ile mutation and in which all of the three most common apolipoprotein E (ApoE) alleles are represented. We studied the relationship between ApoE genotype and the clinical expression of the disease and found that in this amyloid precursor protein-mutated family, ApoE genotype influences the age at onset of the disease. Three mutated subjects heterozygous for the epsilon 4 allele had the earliest age at onset in this family, subjects heterozygous for the epsilon 2 allele had the latest age at onset, and subjects homozygous for the epsilon 3 allele had an intermediate age at onset. In this large kindred we also found an amyloid precursor protein-mutated subject 2.4 standard deviations older than the mean age at onset without clinical signs and symptoms of the disease and carrying the epsilon 2/epsilon 3 genotype.

Adult↗
PubMed1995

Alterations in metabolic properties in fibroblasts in Alzheimer disease.

Alzheimer disease (AD) leads to alterations in several biochemical properties in cultured skin fibroblasts. Because abnormal glucose metabolism has been reported in both in vivo and in vitro studies of the brain, we examined glucose and glutamine oxidation and lactate production in cultured skin fibroblasts from nine patients with familial AD, 19 with sporadic AD, and 20 age-matched controls. The production of CO2 from glucose and glutamine was significantly lower in both groups of Alzheimer fibroblasts compared to controls after 10 min or 1, 2, and 4 h of incubation. The reduction in CO2 production was most evident after 1 h of incubation with either (U-14C)-glucose or (U-14C)-glutamine. Lactate concentration was comparable in all groups at any time of incubation. These findings suggest that processes that require mitochondrial function as glucose or glutamine oxidation are altered in AD and provide evidence that complex metabolic differences are expressed in cultured nonneuronal cells from Alzheimer patients.

Aged↗
PubMed1994

ApoE allele frequencies in Italian sporadic and familial Alzheimer's disease.

Recent studies have provided evidence of association of apolipoprotein E (ApoE) epsilon 4 allele and late onset familial and sporadic Alzheimer's disease (AD). Epidemiological studies have established allelic variation at the ApoE locus. We have analyzed the ApoE gene polymorphism in a sample of 446 Italian subjects. Our data confirm a significant association between epsilon 4 allele and sporadic AD. The frequency of epsilon 4 allele in early onset familial AD patients was comparable to control values suggesting that epsilon 4 allele does not represent a risk factor for early onset familial AD (EOFAD). Moreover, we found a not previously reported association between ApoE epsilon 2 allele and sporadic AD and EOFAD.

Age of Onset↗
PubMed1994

Determination of measles, mumps, and rubella immunization status using oral fluid samples.

OBJECTIVE: To determine if oral fluid samples can be used to reliably assess protective blood levels of antibodies to measles, mumps, and rubella. DESIGN: A comparison of matched serum and oral fluid samples from asymptomatic subjects in enzyme-linked immunosorbent assays for measles, mumps, and rubella antibodies. A longitudinal study compared matched serum and oral fluid samples from 11 subjects after measles-mumps-rubella vaccination. SETTING: Five US clinical sites with samples tested at the reporting laboratory. PARTICIPANTS: A total of 157 asymptomatic subjects including 55 subjects younger than 18 years. MAIN OUTCOME MEASURES AND RESULTS: The presence of antibodies in oral fluid specimens correlated with that in serum with the following levels of sensitivity and specificity: measles, 97% and 100%, respectively; mumps, 94% and 94%, respectively; rubella, 98% and 98%, respectively. Longitudinal studies of subjects after vaccination showed similar seroconversion profiles in oral fluid and serum samples. CONCLUSION: Protective blood levels of antibodies to measles, mumps, and rubella can be assessed by means of an oral fluid sample with good reliability.

Adolescent↗
PubMed1994

Molecular genetics of Alzheimer's disease in Italian families.

We screened 11 families from different regions of Italy by direct sequencing of exon 17 of the APP gene. Two unrelated families carried the APP717 mutation segregating with the disease. These two families originate from two Italian regions which are considered genetically separate. Published studies have demonstrated the presence of the APP717 Val-->Ile mutation in kindreds of British or Japanese origin with early onset familial Alzheimer's disease. These data suggest that the APP717 mutation is not confined to islander families which may share common founders. From the molecular genetic point of view we also did linkage analysis. Several families, in fact, have not shown a linkage with chromosome 21 and the resolution of this dilemma required investigation of those pedigrees both with additional markers from chromosome 21 and with markers from other chromosomes.

Alzheimer Disease↗
PubMed1994

Friedreich's ataxia: MR findings involving the cervical portion of the spinal cord.

OBJECTIVE: Loss of myelinated fibers and gliosis in the posterior and lateral columns of the spinal cord are histopathologic hallmarks of Friedreich's ataxia. These are accompanied by atrophy of the upper portion of the spinal cord. We performed a study to determine if MR imaging can be used to detect signal changes in the white matter tracts of the cervical spinal cord in these patients. SUBJECTS AND METHODS: The cervical spinal cord was imaged with a 0.5-T MR imaging system in 10 patients with Friedreich's ataxia and in 14 patients with cerebellar ataxias, who served as control subjects. In all of them, the examination protocol included sagittal T1-weighted spin-echo images, sagittal short T1 inversion-recovery images, and axial cardiac-gated long TR spin-echo or ungated low-flip-angle (20 degrees) gradient-recalled-echo images from C2 to C6. The anteroposterior diameter of the spinal cord at the level of C3 on axial images was measured on the display console in patients and control subjects. Two observers who did not know the clinical diagnosis were then asked to evaluate hard copies of the entire image set for each subject for possible intramedullary signal abnormalities. RESULTS: The anteroposterior diameter of the spinal cord was decreased in all but one of the patients with Friedreich's ataxia. Abnormal signal in the posterior or lateral columns of the spinal cord was observed on sagittal and axial images in nine patients with Friedreich's ataxia and in none of the control subjects. CONCLUSION: MR images of the cervical spinal cord in patients with Friedreich's ataxia show thinning and intramedullary signal changes in the cervical portion of the spinal cord, consistent with degeneration of posterior and lateral white matter tracts. These MR findings might be helpful for differential diagnosis in patients with progressive ataxia of uncertain clinical type.

Adult↗
PubMed1994

The use of oral fluid for hepatitis C antibody screening.

OBJECTIVES: To assess the efficacy of oral fluid antibody testing for the detection of hepatitis C. METHODS: Paired serum and oral fluid collections were obtained from 216 subjects. A modification of the serum HCV ELISA assay was developed to improve test accuracy for an oral fluid substrate. Sensitivity was determined in 109 HCV serum ELISA-positive patients and specificity in 107 HCV serum ELISA-negative patients. RESULTS: Overall sensitivity of oral fluid collection and testing was 98.2%; specificity was 99.1%. These parameters did not seem to be altered by presence of concurrent hepatitis B infection, inflammatory state of the liver, or other factors. CONCLUSIONS: Oral fluid collection and HCV antibody testing by the modified ELISA method seems to be an effective and efficient alternatives to venipuncture and serum HCV antibody testing. Their use may facilitate epidemiological surveys and evaluation of individual patients when blood collection is not feasible.

Adult↗
PubMed1993

Effect of phosphatidylserine on free radical susceptibility in human diploid fibroblasts.

We studied the effect of phosphatidylserine (PdtSER) on oxygen metabolite toxicity in skin fibroblast cell lines from apparently normal subjects. Fibroblast damage was produced by the generation of oxygen metabolites during the enzymatic oxidation of acetaldehyde by xanthine-oxidase (Xo). In order to quantify cell damage, we measured lactate dehydrogenase (LDH) activity in culture medium and cell viability in fibroblast cultures, with and without preincubation for 4 days with PdtSER 13 microM, after Xo incubation. We found a significant increase of LDH activity in culture medium of cells without preincubation with PdtSER. No significant increase of LDH activity was observed in the same cell lines after preincubation with PdtSER.

Acetaldehyde↗