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Biomedical subjects

J Hardy

Publications and source records attributed to J Hardy.

At least 145 records · Page 8Linked to original sources
PubMed1999

A novel mutation in the apolipoprotein E gene (APOE*4 Pittsburgh) is associated with the risk of late-onset Alzheimer's disease.

Using a combination of polymerase chain reaction (PCR), single-strand conformation polymorphism (SSCP) and DNA sequencing techniques, we identified a unique missense mutation (T-->C) in exon 3 of the APOE gene which resulted in the substitution of pro-28 for leu-28. We screened 1118 White cases of late-onset (>60 years) Alzheimer's disease (AD) from three independent centers (Pittsburgh = 489, Indiana = 319, Mayo Clinic Rochester = 310) and 1123 controls (607 clinically assessed and 516 individuals randomly ascertained from the general population). Two of the 1123 control subjects had the pro-28 mutation (0.18%). However, this mutation was observed in heterozygous state in 2.66, 2.51 and 1.94% of the AD cases from Pittsburgh, Indiana and Mayo Clinic Rochester, respectively, with an overall frequency of 2.42%. All individuals with this mutation were carriers of the APOE*4 allele and hence the mutation was denoted as APOE*4 Pittsburgh (APOE*4P). Compared with the non-E*4P carriers, the E*4P carriers were associated with an increased risk of AD (odds ratio (OR) 13.2) and this risk remained significant even after adjusting for the known effect of APOE*4 (OR 5.4). The risk associated with the E*4P/E*4 combination was about five times (OR 29.1) the risk attributed to APOE*4 carriers alone (OR 5.7). Our data indicates that the new mutation most likely exists in cis-orientation with APOE*4 and is associated with increased risk of developing AD.

Adult↗
PubMed1999

No association between the alpha-2 macroglobulin I1000V polymorphism and Alzheimer's disease.

Recent reports have suggested that variability in the alpha2-macroglobulin gene is a genetic risk factor for Alzheimer's disease. Here we have both tested a common polymorphism in the gene (I1000V) for association with the disease in a four-site case control study design, and tested the locus for linkage in a large series of sibpairs afflicted with late onset disease. Our results fail to show an association between this polymorphism and disease.

Age of Onset↗
PubMed1999

Low frequency of pathogenic mutations in the ubiquitin carboxy-terminal hydrolase gene in familial Parkinson's disease.

A coding substitution (I93M) in the ubiquitin carboxy-terminal L1 (UCH-L1) gene has recently been identified in a German family with Parkinson's disease. We have sequenced the entire coding region of the gene in 11 families who have a pattern of disease consistent with autosomal dominant inheritance. We found a polymorphism (S18Y) in exon 3, two polymorphisms in the 5' non-coding region, upstream of the transcription start, and an insertion/deletion polymorphism in intron 4. The S18Y allele is present on approximately 20% of chromosomes in a Caucasian population. These changes are, therefore, unlikely to be pathogenic. We conclude that the I93M variant must either be a rare cause of disease or a harmless substitution whose occurrence in the family reflects a chance co-occurrence.

Adult↗
PubMed1999

No pathogenic mutations in the persyn gene in Parkinson's disease.

The persyn (gamma-synuclein) gene is highly homologous to the alpha-synuclein gene and is highly expressed in the nervous system. It is therefore, an excellent candidate gene for Parkinson's disease. However, we have sequenced the gene in a large number of families with parkinsonism and failed to find pathogenic mutations.

Age of Onset↗
PubMed1999

Association between coding variability in the LRP gene and the risk of late-onset Alzheimer's disease.

We have sequenced the entire (89 exons) open reading frame of the LRP gene in 12 cases of Alzheimer's disease (AD) from Northern France. We have found no novel changes but confirm the occurrence of a polymorphism in exon 6 of the gene (A216V). This polymorphism is rare (2.8% of controls) and is in linkage equilibrium with previously reported polymorphisms. The V216 allele is negatively associated with the disease in a large case-controlled series. These data suggest that the LRP receptor may be involved in the pathobiology of AD, but the association that we report here cannot explain the previously reported genetic data implicating the LRP gene in AD. If the LRP gene is a major site of genetic variability leading to AD, there must be other biologically relevant variability in promoter or other regulatory elements of this large gene.

Aged↗
PubMed1999

Widespread alterations of alpha-synuclein in multiple system atrophy.

Glial cytoplasmic inclusions (GCI) are the hallmark of multiple system atrophy (MSA), a rare movement disorder frequently associated with autonomic dysfunction. In this study of 21 cases of MSA, GCI were consistently immunoreactive for alpha-synuclein and double-immunostained for ubiquitin and oligodendroglial markers, but not glial fibrillary acidic protein. No statistically significant difference was found in the density of GCI in various brain regions in the two forms of MSA, striatonigral degeneration (SND) and olivopontocerebellar atrophy (OPCA). Postmortem brain samples from 9 cases of MSA were fractionated according to solubility in buffer, Triton-X 100, sodium dodecyl sulfate (SDS), and formic acid, and alpha-synuclein immunoreactivity was measured in Western blots. Total alpha-synuclein immunoreactivity was increased in MSA compared to controls, with no statistically significant difference between SND and OPCA. Most of the increase was due to alpha-synuclein in SDS fractions. In controls this fraction had little or no immunoreactivity. In 7 cases and 4 controls correlations were investigated between quantitative neuropathology and biochemical properties of alpha-synuclein. Surprisingly, the amount of SDS-soluble alpha-synuclein correlated poorly with the number of GCI in adjacent sections. Furthermore, areas with few or no GCI unexpectedly had abundant SDS-soluble alpha-synuclein. These findings provide evidence that modifications of alpha-synuclein in MSA may be more widespread than obvious histopathology. Moreover, these alterations may constitute a biochemical signature for the synucleinopathies.

Aged↗
PubMed1999

Neurodegenerative disease: a different view of diagnosis.

Neurodegenerative diseases have traditionally been defined as clinicopathological entities. Although this has been a productive paradigm in terms of the development of treatment strategies, molecular genetic approaches have revealed that there is overlap between different entities in pathogenic mechanisms. In this article, it is argued that neurodegenerative disease should also be thought of as the consequences of sequential biochemical processes, and that some parts of these processes appear to operate in more than one disease entity. Defining these pathways and, in particular, developing an appreciation of the commonalities between different diseases, should aid in the development of therapies that are effective in several diseases.

Alzheimer Disease↗
PubMed1999

Functionality of nutrients and thermal treatments of food.

Since discovering fire man has used heat to modify the sensory properties and to preserve foodstuffs. Nutrients are involved in a number of reactions induced by this form of treatment. Some of these reactions are desirable, e.g. the improvement in the digestibility and the attractiveness of a food. Some reactions are undesirable because they lead to considerable nutritional loss or may result in the formation of mutagenic and carcinogenic molecules. The present paper reviews recent studies in which most of the modifications generated by thermal treatments at both the industrial and domestic level are demonstrated. We focus on the processes and the importance of thermal treatments used currently, as well as the necessity for optimization to minimize undesirable effects.

Food↗
PubMed1999

Fatigue in advanced cancer: a prospective controlled cross-sectional study.

Uncontrolled studies have reported that fatigue is a common symptom among patients with advanced cancer. It is also a frequent complaint among the general population. Simply asking cancer patients whether or not they feel fatigued does not distinguish between the 'background' level of this symptom in the community and any 'excess' arising as a result of illness. The aim of this study was to determine the prevalence of fatigue among palliative care inpatients in comparison with a control group of age and sex-matched volunteers without cancer. In addition, the correlates of fatigue were investigated. The prevalence of 'severe subjective fatigue' (defined as fatigue greater than that experienced by 95% of the control group) was found to be 75%. Patients were malnourished, had diminished muscle function and were suffering from a number of physical and mental symptoms. The severity of fatigue was unrelated to age, sex, diagnosis, presence or site of metastases, anaemia, dose of opioid or steroid, any of the haematological or biochemical indices (except urea), nutritional status, voluntary muscle function, or mood. A multivariate analysis found that fatigue severity was significantly associated with pain and dypnoea scores in the patients, and with the symptoms of anxiety and depression in the controls. The authors conclude that subjective fatigue is both prevalent and severe among patients with advanced cancer. The causes of this symptom remain obscure. Further work is required in order to determine if the associations reported between fatigue and pain and between fatigue and dyspnoea are causal or coincidental.

Adult↗
PubMed1999

Antisense-induced reduction of presenilin 1 expression selectively increases the production of amyloid beta42 in transfected cells.

Autosomal dominant mutations in the presenilin 1 (PS1) gene are associated with familial, early-onset Alzheimer's disease. Although the pathogenic mechanism of these mutations is unclear, their common feature is that they lead to an increased concentration of amyloid beta-peptide (Abeta) 42 in the plasma of early-onset patients, in the conditioned media of transfected cells, and in the brains of transgenic mice that overexpress mutant PS1. To address the mechanism(s) by which the pathogenic PS1 mutations increase Abeta42, we constructed human cell lines expressing a doxycyclin (dox)-inducible antisense PS1 RNA and measured its effects on the levels of PS1, amyloid precursor protein (APP), and Abeta. In time course experiments, we observed a statistically significant (p = 0.0038) more than twofold elevation in secreted Abeta42 as early as 12 days after addition of dox. This correlated with an 80% decrease in the 46-kDa PS1 holoprotein and a 30% decrease in the 26-kDa N-terminal fragment (NTF). Furthermore, there was a significant fivefold (p = 0.002) increase in Abeta42 after 14-day dox treatment; this correlated with a >90% decrease in PS1 holoprotein and 60% decrease in NTF. At no time point did we observe significant changes in Abeta40, APP holoprotein, presenilin 2, or tubulin. Ten days after the removal of dox, we observed a return to constitutive levels for Abeta42, PS1 holoprotein, and NTF. These results suggest that in human cell lines, the reduction of normal PS1 activity results in the increased production of Abeta42. Furthermore, our results are consistent with a loss of function or dominant negative mechanism for the pathogenic PS1 mutations.

Alzheimer Disease↗
PubMed1999

A chromosome 4p haplotype segregating with Parkinson's disease and postural tremor.

We investigated a large family with levodopa-responsive, Lewy body parkinsonism in which the disease segregates as an apparent autosomal dominant trait. After performing a genome screen, we identified a chromosome 4p haplotype that segregates with the disease. However, this haplotype also occurs in individuals in the pedigree who do not have clinical Lewy body parkinsonism but rather suffer from postural tremor, consistent with essential tremor. These data demonstrate a new locus for Lewy body parkinsonism and suggest that in some circumstances postural tremor can be an alternative phenotype of the samepathogenic mutation as Lewy body parkinsonism.

Chromosome Mapping↗
PubMed1999

The genetics of disorders with synuclein pathology and parkinsonism.

Despite being considered the archetypal non-genetic neurological disorder, genetic analysis of Parkinson's disease has shown that there are at least three genetic loci. Furthermore, these analyses have suggested that the phenotype of the pathogenic loci is wider than simple Parkinson's disease and may include Lewy body dementia and some forms of essential tremor. Identification of alpha-synuclein as the first of the loci involved in Parkinson's disease and the identification of this protein in pathological deposits in other disorders has led to the suggestion that it may share pathogenic mechanisms with multiple system atrophy, Alzheimer's disease and prion disease and that these mechanisms are related to a synuclein pathway to cell death. Finally, genetic analysis of the synuclein diseases and the tau diseases may indicate that this synuclein pathway is an alternative to the tau pathway to cell death.

Alzheimer Disease↗