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Biomedical subjects

G Vaula

Publications and source records attributed to G Vaula.

At least 19 recordsLinked to original sources

MRI and CT in an autosomal-dominant, adult-onset leukodystrophy.

We report MRI findings in a family with an autosomal-dominant, adult-onset neurological disorder. The clinical picture, the white matter changes detected on MRI and the absence of any laboratory abnormality suggested the diagnosis of leukodystrophy with an unknown biochemical defect. Autosomal-dominant inheritance is extremely rare in this kind of disease, and most reported families have not undergone MRI. We performed MRI and clinical examination of 17 members of our family; 9 affected subjects, at different stages of the disease, were detected. The most characteristic MRI findings were initially symmetrical areas of signal change in the white matter of the trigonal region; demyelination extending thereafter to the frontal and parietal regions, partially involving subcortical white matter; the temporal lobe and optic radiations were less involved; the internal capsule and corpus callosum were involved later, in a dorsoventral direction; patchy demyelination was evident in the late stages in the brain stem; the cerebellum was spared even in the latest stages of the disease. While pathological examination is essential to characterise and classify these kinds of diseases, MRI can make substantial contributions to understanding their natural history, and to detect early signs of the disease.

Adolescent↗

Autosomal dominant late-onset leukoencephalopathy. Clinical report of a new Italian family.

The adult-onset autosomal dominant leukoencephalopathies are rare disorders. Very few pedigrees have been extensively described and no biochemical or genetic marker has been identified so far. The present study was aimed to characterized an autosomal dominant late-onset leukoencephalopathy occurring in a large Italian kindred. A genealogic method was adopted to ascertain 51 affected individuals among nearly 400 subjects in 8 generations. Medical records were obtained from 11 deceased patients. We personally examined 8 symptomatic and 9 asymptomatic at-risk individuals who underwent a standardized clinical, biochemical, radiological and neurophysiological study. The mean age at onset of the disease was 46.6 years and the mean duration of disease 9.9 years. The clinical picture was characterized by progressive pyramidal and pseudobulbar signs, urinary incontinence and, sometimes, action tremor of the head and/or hands. No relevant mental deterioration was noted. In all the symptomatic and in 1 asymptomatic subject, brain MRI showed marked symmetrical hyperintensity on T2-weighted images of the white matter of the cerebral hemispheres, with constant sparing of the cerebellum. In these subjects, evoked potentials revealed altered central neural conduction. Nerve conduction velocity, biochemical (including lysosomal enzymatic activities) and biopsy (peripheral tissue specimens) examination were normal. The clinical and neuroradiological data are consistent with an autosomal dominant adult-onset leukoencephalopathy whose features are unusual when compared to those previously reported.

Adult↗

Protein-DNA interactions in the promoter region of the amyloid precursor protein (APP) gene in human neocortex.

We have investigated protein-DNA interactions in the proximal promoter of the human amyloid precursor protein (APP) gene in temporal lobe neocortical nuclei isolated from control and Alzheimer disease (AD) affected brains. We report that the human APP 5' promoter sequence from -203 to +55 bp, which has been previously reported to contain essential regulatory elements for APP gene transcription, lies in a deoxyribonuclease I, micrococcal nuclease- and restriction endonuclease-sensitive, G+C-rich nucleosome-free gap flanked both 5' and 3' by typical nucleosome structures. As analyzed by electrophoretic mobility shift assay, this extended internucleosomal linker DNA is heavily occupied by nuclear protein factors, and interacts differentially with nuclear protein extracts obtained from HeLa and human brain neocortical nuclei. This suggests that the chromatin conformation of the APP gene promoter may vary in different cell types, and may correlate with differences in APP gene expression. Human recombinant transcription factors AP1, SP1 and TFIID (but not AP2 or brain histones H1, H2B and H4) interact with the -203 to +55 bp of the human APP promoter sequence. Only minor differences were observed in the chromatin structure of the immediate APP promoter between non-AD and AD affected neocortical nuclei, suggesting either that post-transcriptional processes, or that regulatory elements lying elsewhere in the APP gene may be important in the aberrant accumulation of the APP gene product.

Aged↗

Analysis of the functional effects of a mutation in SOD1 associated with familial amyotrophic lateral sclerosis.

Mutations in the Cu, Zn superoxide dismutase (SOD1) gene have been reported in some pedigrees with Familial Amyotrophic Lateral Sclerosis (FALS). We have investigated the functional and structural effects of a Gly-->Ser mutation at codon 41 of SOD1 in a pedigree with FALS and the topography of SOD1 expression in the mammalian CNS. These analyses show that the 41Gly-->Ser mutation causes a 27% reduction in Cu, Zn SOD activity. SOD1 is transcribed at high levels in rat motoneurons and four other types of neurons homologous to upper motoneurons that degenerate in human ALS. However, SOD1 is transcribed at lower levels in other types of neurons, such as cerebellar Purkinje cells, which are not usually involved significantly in human ALS. On the other hand, immunocytochemical studies indicate that most types of rat neurons contain similar levels of Cu, Zn SOD immunoreactive protein. Nevertheless, these results suggest that the essential feature causing this subtype of ALS is either a reduction in Cu, Zn SOD activity in cell types that presumably critically require Cu, Zn SOD for protection against oxidative damage or the fact that the mutation in SOD1 associated with FALS results in a novel gain of function that is particularly deleterious to those cell types expressing SOD1 at high levels.

Amino Acid Sequence↗

Assessment of genetic polymorphisms in DNA from formalin fixed neurological tissues.

The ability to analyze the genotype of deceased affected members of pedigrees segregating inherited neurological diseases considerably augments the informativeness of such pedigrees. This information has direct application in attempts to isolate disease genes by positional cloning strategies, and for genetic counselling. We show that the genotype at polymorphic simple sequence repeat loci can be determined from genomic DNA isolated from 10 micron thick paraffin embedded, formalin fixed neurological tissues. The critical constraint on this method is the size of the template target bearing the simple sequence repeat, which should ideally be less than 165 base pairs.

Alzheimer Disease↗

SOD1 missense mutation in an Italian family with ALS.

We have discovered a new Italian pedigree with autosomal-dominant ALS. The pedigree, at present, comprises 75 members distributed in five generations. ALS was diagnosed in eight patients. The mean +/- SD age of onset of the disease was 46.8 +/- 13.5 years, with a range of 29 to 63 years. The mean +/- SD duration of the disease was 11.6 +/- 1.7 months. Molecular genetic studies showed a missense mutation (Gly-->Ser, codon 41) in exon 2 of the Cu/Zn superoxide dismutase gene (SOD1) on chromosome 21 in the available affected member and in 45% of the at-risk subjects of the pedigree. This study confirms the presence of SOD1 point mutations in families with autosomal-dominant ALS and suggests that additional genetic or environmental factors may be involved in the full expression of the disease.

Adult↗

Analysis of the c-FOS gene on chromosome 14 and the promoter of the amyloid precursor protein gene in familial Alzheimer's disease.

The c-FOS gene product, a putative transacting transcriptional regulator of the amyloid precursor protein (APP) gene, is a candidate locus for the familial Alzheimer's disease (FAD) mutation on chromosome 14 (FAD14). In light of this functional relationship, we investigated the nucleotide sequence and segregation of c-FOS and the nucleotide sequence of the 5' APP promoter. Single-stranded conformational polymorphisms (SSCPs) in the c-FOS gene revealed that c-FOS closely cosegregates with the FAD14 gene but does not show allelic association with FAD. A conservative third-position T-->C mutation was demonstrated in exon 2 (codon 84) of c-FOS, and a C-->G substitution was detected at -209 bp in the 5' promoter of APP. Neither were unique to FAD and are unlikely to be pathogenic or secondary modifiers of the FAD phenotype. We conclude that the c-FOS open reading frame is probably not the site of the FAD14 locus, but we cannot exclude the existence of modifier loci on chromosome 21.

Adult↗

A novel but non-pathogenic mutation in exon 4 of the human amyloid precursor protein (APP) gene.

Mutations in the beta-amyloid precursor protein (APP) gene have been associated with both familial Alzheimer disease (FAD) and with hereditary cerebral haemorrhage. The polymerase chain reaction was used to both amplify and sequence exon 4 of the APP gene from genomic DNA of subjects with FAD and normal control subjects. A novel, rare, conservative DNA sequence variant was discovered at nucleotide 459 of codon 153 (valine) in exon 4 of the APP gene in an affected member of a large FAD pedigree. Segregation studies indicate that this mutation is likely to be non-pathogenic, but must be recognized and discriminated from pathogenic mutations during sequencing studies of the APP gene in patients with FAD.

Amyloid beta-Protein Precursor↗

Genetic evidence for a novel familial Alzheimer's disease locus on chromosome 14.

Familial Alzheimer's disease (FAD) has been shown to be genetically heterogeneous, with a very small proportion of early onset pedigrees being associated with mutations in the amyloid precursor protein (APP) gene on chromosome 21, and some late onset pedigrees showing associations with markers on chromosome 19. We now provide evidence for a major early onset FAD locus on the long arm of chromosome 14 near the markers D14S43 and D14S53 (multipoint lod score z = 23.4) and suggest that the inheritance of FAD may be more complex than had initially been suspected.

Aged↗

Molecular and prospective phenotypic characterization of a pedigree with familial Alzheimer's disease and a missense mutation in codon 717 of the beta-amyloid precursor protein gene.

We present prospective clinical and neuropathologic details of a pedigree segregating familial Alzheimer's disease (FAD) associated with a mutation (G----A substitution) at nucleotide 2149 in exon 17 of the amyloid precursor protein (APP) gene. This mutation, which is predicted to cause the missense substitution of isoleucine for valine at codon 717 of APP, cosegregated perfectly with the FAD trait (lod score = 3.49 at theta = 0.00). The earliest clinical manifestations of the disease relate to deficits in memory function, cognitive processing speed, and attention to complex cognitive sets. These changes occurred in the absence of changes in nonmemory language and visuospatial functions. The neuropathologic features of FAD associated with the APP717 mutation in this family include severe neuronal loss, abundant neurofibrillary tangles, amyloid plaques, and amyloid angiopathy. These results provide independent confirmation that mutations in the APP gene are linked to the FAD trait in some families.

Adult↗

Assessment of amyloid beta-protein precursor gene mutations in a large set of familial and sporadic Alzheimer disease cases.

A genetic locus associated with familial Alzheimer disease (FAD) and a candidate gene, APP, encoding the amyloid protein precursor have both been assigned previously to chromosome 21, and, in a few FAD families, mutations of APP have been detected. However, obligate crossovers between APP and FAD have also been reported in several FAD pedigrees, including FAD4, a large kindred showing highly suggestive evidence for linkage of the disorder to chromosome 21. In case the apparent APP crossover in FAD4 actually represented an intragenic recombination event or segregation of different mutations in different family branches, we have performed a more detailed assessment of APP as a candidate gene in this family. The entire coding region of the APP gene was sequenced for FAD4 and for FAD1, a second large kindred. No mutations were found, indicating that, in at least one chromosome 21-linked FAD pedigree, the gene defect is not accounted for by a mutation in the known coding region of the APP gene. A total of 25 well-characterized early- and late-onset FAD pedigrees were typed for genetic linkage to APP, to assess the percentage of FAD families predicted to carry mutations in the APP gene. None of the FAD families yielded positive lod scores at a recombination fraction of 0.0. To estimate the overall prevalence of FAD-associated mutations in the beta A4 domain of APP, we sequenced exons 16 and 17 in 30 (20 early- and 10 late-onset) FAD kindreds and in 11 sporadic AD cases, and we screened 56 FAD kindreds and 81 cases of sporadic AD for the presence of the originally reported FAD-associated mutation, APP717 Val----Ile (by BclI digestion). No APP gene mutations were found in any of the FAD families or sporadic-AD samples examined in this study, suggesting that the mutations in exons 16 and 17 are a rare cause of FAD. Overall, these data suggest that APP gene mutations account for a very small portion of FAD.

Alzheimer Disease↗

c-met is amplified but not mutated in a cell line with an activated met tyrosine kinase.

The putative tyrosine kinase receptor encoded by the oncogene c-met is activated (tyrosine-phosphorylated in vivo) in the human gastric carcinoma cell line GTL-16. The corresponding gene is amplified and over-expressed. In this study we show that c-met is part of an amplification unit measuring more than 3000 kb. The multiple copies of the amplicon are located on a novel chromosome different from chromosome 7. We have previously shown that the c-met protein present in GTL-16 cells is indistinguishable from that found in other cells. Kinase activation could be due to over-expression of the normal c-met protein or to the presence of activating mutation(s). To verify the primary structure of the c-met protein in GTL-16 cells we sequenced a series of overlapping cDNAs obtained from GTL-16 cell RNA by reverse transcription and polymerase chain reaction. Two differences were found in the c-met coding region with respect to the published human c-met cDNA: (1) the lack of 54 nucleotides corresponding to a stretch of 18 amino acids located in the extracellular domain of the receptor, and (2) the substitution of the codon specifying alanine 1209 (located in the tyrosine kinase domain) with one coding for glycine. However, we also obtained cDNAs identical to that just described from a number of control cell lines. These results suggest: (1) that the present c-met cDNA presumably reflects the sequence of the most abundant transcript in several cell types, and (2) that over-expression of the normal c-met protein, alone or in combination with an autocrine loop, is most probably responsible for the activation of the c-met kinase in GTL-16 cells.

Base Sequence↗

Familial Alzheimer's disease. Evidences for clinical and genetic heterogeneity.

We report the genealogical, clinical and molecular genetic findings of a new family with autosomal dominant early-onset Alzheimer's disease (FAD) discovered in Torino (Italy). Up to now, the pedigree comprises 1500 members, distributed in 8 generations. 22 patients affected with Alzheimer's disease have been identified. The clinical course of the disease was fairly uniform in all the patients. An high incidence of myoclonic jerks and epileptic seizures was found. Molecular genetic studies showed the presence of positive but nonsignificant lod scores between chromosome 21 anonymous DNA markers and the disease. The data obtained from the Torino family were computed together with those of additional 47 pedigrees, with both early-onset and late-onset Alzheimer's disease. A predisposing locus for the disease was found on the pericentromeric region of chromosome 21 only in early-onset FAD pedigrees.

Adult↗

[Plasma beta-endorphin and caffeine consumption in chronic hemicrania].

Thanks to recent biochemical and neuroendocrine findings, migraine belonging to the group of primary headaches appears as a pathology of the antinociceptive system with evolutive character. It has been demonstrated, in fact, that right at the early stage of migraine, there is a significant reduction in liquoral concentrations of beta-endorphin (beta-E), endogenous opioid peptide followed by a similar change in the plasma opioid system. The opioid system deficiency is even more evident after stimulation tests that point to reduced reactivity of the hypothalamo-hypophyseal system with respect to stimuli that in normal subjects trigger hypophyseal beta-E incretion. Caffeine, a member of the methyl-xanthine group, is an interesting molecule in the study of migraine patients because the chronic intake of this substance, contained in numerous analgesics, has been related to the chronic nature of the pain. The purpose of the present study is to assess the relationship between caffeine consumption and plasma opioid system. With the administration of a single oral dose of caffeine, normal subjects present an increase in plasma concentrations of beta-E, while in patients with chronic migraine, the response is significantly lower. These data confirm the poor reactivity of the plasma opioid system to pharmacological stimuli in migraine. Average daily consumption of caffeine has also been determined. It was not possible to establish a correlation between consumption of caffeine and plasma concentrations of beta-E whether basal or after stimulus with caffeine.

Administration, Oral↗

Association between the interleukin-1alpha gene and Alzheimer's disease: a meta-analysis.

Inflammatory processes are involved in the pathogenesis of Alzheimer's disease (AD). Several studies have addressed the effects of interleukin-1 (IL-1) genes polymorphisms on the risk of developing AD. The results are not in full agreement on whether these polymorphisms are associated with the disease. To clarify this issue, we performed a meta-analysis of all the association studies between IL-1 genes and AD. Due to the relatively small number of published articles, the meta-analysis was restricted to the association of the IL-1alpha -889 C/T gene polymorphism and AD. Under a random effects model, the risk for the disease was significantly higher in subjects with the T/T genotype in comparison with both C/T (OR: 1.51; 95% C.I.: 1.15-1.99) and C/C (OR: 1.49; 95% C.I.: 1.09-2.03) subjects. There was modest heterogeneity for these effect estimates. Analysis of subgroups showed a significant association in patients with early-onset AD but not in late-onset AD. Our data support a significant but modest association between the T/T genotype of the IL-1alpha gene and AD.

Aged↗