Low frequency of alpha-synuclein mutations in familial Parkinson's disease

A mutation in exon 4 of the alpha-synuclein (NACP) gene has been reported to explain the chromosome 4 linkage to autosomal dominant Parkinson's disease. We developed primers and methods for exonic sequencing of this gene and sequenced the entire coding region of the gene in 6 families with autosomal dominant disease and in 2 cases of lytico and bodig from Guam. In addition, we have sequenced exon 4 of this gene in 5 cases of familial disease and have screened for the specific mutation (A53T) in a 40 cases of idiopathic Parkinson's disease, 3 cases of multisystem atrophy, and 15 cases of Lewy body dementia. We have found no genetic variation in the gene. We discuss these findings with respect to both the epidemiology of Parkinson's disease and the possibility that NACP is not the chromosome 4 locus for disease.

Effect of synovial membrane infection in vitro on equine synoviocytes and chondrocytes

OBJECTIVE

To determine the functional response of synovium to infection, and the influence of infected synovium on articular cartilage metabolism.

SAMPLE POPULATION

Synovium and articular cartilage explants from the midcarpal and tarsocrural joints of adult horses.

PROCEDURE

For experiment 1, synovium explants were incubated as follows: control--incubation in standard medium, infected (I)--incubation with Staphylococcus aureus, and infected-filtered (IF)--incubation with medium collected from the infected group and filtered (0.22-micron filter). Daily collected medium was assayed for interleukin 1 beta (IL-1 beta), IL-6, tumor necrosis factor, and hyaluronan (HA) concentrations. For experiment 2, cartilage explants were incubated as follows: control--incubation in standard medium, and IF--incubation in medium collected from infected synovium cultures and filtered. After 48 hours, explant proteoglycan synthesis and endogenous proteoglycan and glycosaminoglycan contents were determined.

RESULTS

IL-1 beta and IL-6 values were significantly increased in synovium explants from the I and IF groups. Hyaluronan concentration was lower in I and IF groups. Proteoglycan synthesis and content, and total glycosaminoglycan and chondroitin sulfate concentrations, were significantly decreased in cartilage from the IF group.

CONCLUSIONS

Bacterial infection was associated with decreased HA concentration and increased mediator release. These effects were also observed despite elimination of bacteria. Exposure to sterile but previously infected medium decreased articular cartilage matrix synthesis and composition.

CLINICAL RELEVANCE

Resident synovial cells may contribute appreciably to articular damage during bacterial infection in the absence of migrant inflammatory cells. This response is prolonged despite elimination of the bacteria.

ApoE genotype is a risk factor in nonpresenilin early-onset Alzheimer's disease families

The apolipoprotein E (ApoE) genotype is a significant risk factor and modulator of age of onset of Alzheimer's disease (AD). We analyzed the effect of the ApoE genotype in two distinct early-onset familial AD groups: families with a mutation in the presenilin-1 gene (PS-1) on chromosome 14, and families without a mutation detectable in the PS-1, presenilin-2 (PS-2), and the amyloid precursor protein (APP) gene (non-PS early-onset familial AD). The ApoE genotype is clearly shown not to modulate age of onset in families with a mutation in the PS-1 gene and families with no lesion detectable in either the presenilin or APP gene. The effects of a double dose of ApoE4 on age of onset were not assessed in the PS-1 AD families due to the lack of any affected ApoE4 homozygotes in the sample set; this insufficiency will need to be assessed in further studies. There was no association between the ApoE4 allele and AD in the PS-1 families. Non-PS early-onset AD families were shown to have a significantly higher frequency of ApoE4 compared to controls and the PS-1 AD group. These observations are important and suggest that 1) other genetic and environmental factors modify the AD phenotype in PS-1 and non-PS early-onset families; and 2) the ApoE4 allele is a significant risk factor in the etiology of non-PS early-onset AD and will be a useful adjunct in the diagnosis of unaffected family members.

Increased Abeta42(43) from cell lines expressing presenilin 1 mutations

Mutations in the presenilin 1 (PS1) gene on chromosome 14 are a major cause of autosomal dominant, early-onset Alzheimer's disease. Here, we show that transfecting cells with several mutant, but not wild-type, PS1 cDNAs alters the processing of the amyloid precursor protein (APP) such that more Abeta42(43) is produced, confirming and extending several recent reports. The most effective mutation in this regard was the exon 9 splice-out mutation (delta9). The correlation between the size of the effect on APP processing and the age of onset of disease assessed in families with the mutations was not informative, and the possible reasons for this are discussed.

Accelerated Alzheimer-type phenotype in transgenic mice carrying both mutant amyloid precursor protein and presenilin 1 transgenes

Genetic causes of Alzheimer's disease (AD) include mutations in the amyloid precursor protein (APP), presenilin 1 (PS1), and presenilin 2 (PS2) genes. The mutant APP(K670N,M671L) transgenic line, Tg2576, shows markedly elevated amyloid beta-protein (A beta) levels at an early age and, by 9-12 months, develops extracellular AD-type A beta deposits in the cortex and hippocampus. Mutant PS1 transgenic mice do not show abnormal pathology, but do display subtly elevated levels of the highly amyloidogenic 42- or 43-amino acid peptide A beta42(43). Here we demonstrate that the doubly transgenic progeny from a cross between line Tg2576 and a mutant PS1M146L transgenic line develop large numbers of fibrillar A beta deposits in cerebral cortex and hippocampus far earlier than their singly transgenic Tg2576 littermates. In the period preceding overt A beta deposition, the doubly transgenic mice show a selective 41% increase in A beta42(43) in their brains. Thus, the development of AD-like pathology is substantially enhanced when a PS1 mutation, which causes a modest increase in A beta42(43), is introduced into Tg2576-derived mice. Remarkably, both doubly and singly transgenic mice showed reduced spontaneous alternation performance in a "Y" maze before substantial A beta deposition was apparent. This suggests that some aspects of the behavioral phenotype in these mice may be related to an event that precedes plaque formation.

Chromosome 14 familial Alzheimer's disease: the clinical and neuropathological characteristics of a family with a leucine-->serine (L250S) substitution at codon 250 of the presenilin 1 gene

BACKGROUND

Seven affected members are described from a kindred with autosomal dominant familial Alzheimer's disease associated with a novel mutation in the presenilin 1 (PS1) gene on chromosome 14 that results in a leucine to serine substitution at codon 250 (L250S).

METHOD

Clinical information on the pedigree was collected directly from family members including affected members and their carers and also from hospital records.

RESULTS

Detailed clinical information was available on five members. All had an early age at onset with a median age of 52 (95% confidence interval (95% CI) 49.4-54.9). Age at onset varied between 49 and 56 years, with duration of illness varying between six years and 15 years. Myoclonus, depression, and psychosis were features of this pedigree; seizures were not reported.

CONCLUSIONS

PS1 L250S familial Alzheimer's disease is an early onset form of Alzheimer's disease with clinical features similar to other reported familial Alzheimer's disease pedigrees, except that seizures were absent.

Cell trafficking, mediator release, and articular metabolism in acute inflammation of innervated or denervated isolated equine joints

OBJECTIVES

To describe the acute cellular response, inflammatory mediator release, and effect on chondrocyte metabolism of interleukin 1 beta (IL-1 beta) in isolated innervated or denervated equine metacarpophalangeal joints.

ANIMALS

One metacarpophalangeal joint of 24 adult horses.

PROCEDURES

The metacarpophalangeal joint was isolated for 6 hours in a pump-perfused, auto-oxygenated, innervated or denervated metacarpophalangeal joint preparation. Isolated joints were assigned to 4 groups: control, control-denervated, inflamed, and inflamed-denervated, and inflammation was induced by intra-articular injection of IL-1 beta. Synovial fluid was collected for cytologic examination and determination of IL (IL)-1 beta, (IL-6), prostaglandin E2 (PGE2), and substance P (SP) values. Synovial membrane was immunostained with SP and nerve-specific enolase (NSE) antibodies. Cartilage was collected for determination of proteoglycan (PG) synthesis and degradation.

RESULTS

IL-1 beta induced significant neutrophilic leukocytosis in synovial and synovial membrane. IL-1 beta concentration and returned to baseline by 5.5 hours, but IL-6 concentration significantly increased throughout the study. Total SP content was significantly higher in inflamed joints. There was a significant increase in 24- and 48-hour PG degradation in inflamed innervated joints.

CONCLUSION

Cellular response to IL-1 beta was rapid and sustained; joint clearance of IL-1 beta was rapid, and endogenous production of IL-1 beta did not follow. The IL-6 and PGE2 concentrations significantly increased, and SP content was increased in association with inflammation but not denervation. A degradative response of cartilage of IL-1 beta was observed, and was enhanced by innervation. This model was useful for investigation of the articular response to acute inflammation and the influence of denervation in modulating this response.

Estimation of the genetic contribution of presenilin-1 and -2 mutations in a population-based study of presenile Alzheimer disease

Two closely related genes, the presenilins ( PS ), located at chromosomes 14q24.3 and 1q42.1, have been identified for autosomal dominant Alzheimer disease (AD) with onset age below 65 years (presenile AD). We performed a systematic mutation analysis of all coding and 5'-non-coding exons of PS -1 and PS -2 in a population-based epidemiological series of 101 unrelated familial and sporadic presenile AD cases. The familial cases included 10 patients of autosomal dominant AD families sampled for linkage analysis studies. In all patients mutations in the amyloid precursor protein gene ( APP ) had previously been excluded. Four different PS -1 missense mutations were identified in six familial cases, two of which where autosomal dominant cases. Three mutations resulted in onset ages above 55 years, with one segregating in an autosomal dominant family with mean onset age 64 years (range 50-78 years). One PS -2 mutation was identified in a sporadic case with onset age 62 years. Our mutation data provided estimates for PS -1 and PS -2 mutation frequencies in presenile AD of 6 and 1% respectively. When family history was accounted for mutation frequencies for PS -1 were 9% in familial cases and 18% in autosomal dominant cases. Further, polymorphisms were detected in the promoter and the 5'-non-coding region of PS -1 and in intronic and exonic sequences of PS -2 that will be useful in genetic association studies.

Food materials adhesion: a review

This article reviews the various theories of adhesion mechanism and, more specifically, studies concerning foodstuffs adhesion to industrial equipment and packaging surfaces. Adhesion is governed by mechanical interlocking, wetting, electrostatic and chemical forces, and diffusion. Direct conclusions about the validity of one of these theories were seldom made in the empirical studies reviewed. The different food adhesion determination methods were detailed: direct observations, evaluations (weighting, UV absorbance, and adhesive loss), adhesion strength measurements, and indirect measurements via the wetting theory (tilted plane method, contact angle, and surface tension). The importance of proteins, product rheological properties, solid surface rugosity, and wetting phenomena in many adhesion cases is highlighted. Conclusions were made that fundamental mechanisms of food-contact surfaces interactions still need to be investigated to improve understanding in the science of food materials.

Localization of frontotemporal dementia with parkinsonism in an Australian kindred to chromosome 17q21-22

An Australian family with autosomal dominant presenile nonspecific dementia was recently described. The disease results in behavioral changes, usually disinhibition, followed by the onset of dementia accompanied occasionally by parkinsonism. Twenty-eight affected individuals were identified with an age of onset of 39 to 66 years (mean, 53 +/- 8.9 years). We mapped the disease locus to an approximately 26-cM region of chromosome 17q21-22 with a maximum two-point LOD score of 2.87. Affected individuals share a common haplotype between markers D17S783 and D17S808. This region of chromosome 17 contains the loci for several neurodegenerative diseases that lack distinctive pathological features, suggesting that these dementias, collectively referred to as frontotemporal dementia with parkinsonism linked to chromosome 17 (FTDP-17), are caused by mutations in the same gene. The entire coding region of five genes, mapped to the FTDP-17 candidate region, were also sequenced. This analysis included the microtubule-associated protein tau that is the major component of the paired helical filaments observed in Alzheimer's disease. No pathogenic mutations were identified in either the tau gene or in any of the other genes analyzed.

A new pathogenic mutation in the APP gene (I716V) increases the relative proportion of A beta 42(43)

We report a novel mutation in the amyloid precursor protein gene (APP I716V) which probably leads to familial early onset Alzheimer's disease with an onset age in the mid 50s. Cells transfected with cDNAs bearing this mutation produce more A beta 1-42(43) than those transfected with wild-type APP and this effect is additive with that of the previously reported APP V717I mutation thus providing a novel approach for further increasing A beta 1-42(43) in model systems.

Distortion of allelic expression of apolipoprotein E in Alzheimer's disease

The APOE epsilon4 allele is a strong genetic susceptibility factor for Alzheimer's disease. Interaction with other biological factors may modulate the effect of the apoE isoforms. However, previous work suggested that other genetic variability within the APOE locus, influencing the effect of the epsilon4 allele, may exist. Such variability could modify the expression of the APOE gene and, in particular, the level of expression of APOE alleles could be an important determinant of disease pathogenesis. To test this hypothesis we examined the levels of expression of APOE in heterozygotes with AD and in controls, using a new method of semi-quantitation. We report that relative epsilon4 mRNA expression is increased in AD compared with controls and suggest that genetic variability in the neural expression of APOE contributes to disease risk.

The presenilins and Alzheimer's disease

The presenilin 1 and presenilin 2 genes have been identified as pathogenic loci involved in the majority of early onset, autosomal dominant Alzheimer's disease. A series of (predominantly) missense mutations have been identified in the two genes which lead to disease. The presenilins are probably eight transmembrane domain proteins with both termini in the cytoplasmic compartment. They have a wide tissue distribution and are found in the endoplasmic reticulum and early Golgi. The mechanism of pathogenesis of the mutations is not clear although, both in patients and in in vitro systems, the effects of presenilin mutations are reminiscent of the effects of the pathogenic mutations in the amyloid precursor protein gene which lead to increases in the amount of amyloid-beta42(43) being produced from the metabolism of the amyloid protein precursor. Thus, the presenilin data provide independent support for the amyloid cascade hypothesis of Alzheimer's pathogenesis. Work on the Caenorhabditis elegans homologues of the presenilins, spe-4 and sel-12, suggests that the presenilins may have a more general and direct role in the processing and trafficking of membrane-bound proteins and that, in part, the pathogenic mutations may disrupt this role.

Early-onset Alzheimer's disease with a presenilin-1 mutation at the site corresponding to the Volga German presenilin-2 mutation

We describe a new mutation causing Alzheimer's disease (AD) in presenilin-1 (N135D) that is at the homologous site to the presenilin 2 mutation (N141I) in Volga German kindreds. The phenotype of PS1 N135D is an early-onset (34-38 years) disease. The mutation forms part of, and extends, the alpha-helical array of mutations in transmembrane 2 of the presenilins and leads to the suggestion that disruption of this helical face is the molecular insult that leads to disease.

Association between the low density lipoprotein receptor-related protein (LRP) and Alzheimer's disease

Alzheimer's disease (AD) is the most common neurodegenerative disorder affecting elderly people. It usually occurs after 65 years old (late-onset AD). The epsilon4 allele of apolipoprotein E (APOE) gene is a risk factor which contributes about 50% of the genetic risk for this form of the disease. The low density lipoprotein receptor-related protein (LRP) is a major receptor for APOE which is found in the senile plaques of AD brains. This makes it a good candidate gene for the disease. There is a polymorphism in the region upstream of the LRP gene that has been associated with AD in an American population. We examined this polymorphism by restriction fragment length polymorphism analysis in a French population with sporadic late-onset AD. In the previous report, a significant increase of the 87 bp allele was found in the AD cases; however, in our population, we observed a significant decrease with this same allele of the LRP gene. The possible reasons for this discrepancy, linkage disequilibrium or statistical anomaly, are discussed.

Risk of hospitalization because of aseptic meningitis after measles-mumps-rubella vaccination in one- to two-year-old children: an analysis of the Vaccine Safety Datalink (VSD) Project

OBJECTIVE

To assess the level of increased risk, if any, of hospitalizations for aseptic meningitis after Jeryl-Lynn mumps strain measles-mumps-rubella (MMR) vaccine in the Vaccine Safety Datalink population.

STUDY DESIGN

A possible increased risk of aseptic meningitis 8 to 14 days after receipt of MMR was observed in a preliminary screening analysis of automated data from the Vaccine Safety Datalink (VSD) project Year 2 analysis. To further evaluate this association a retrospective 10-year matched case-control study was undertaken in the four health maintenance organizations (HMOs) in the VSD project. Cases ascertained from a broad scan of the automated data were validated against a standard case definition. Two controls matched on age, sex, HMO and HMO membership were assigned per case.

RESULTS

The VSD project involves the cooperative collection of automated vaccination and medical outcome data from four large HMOs that currently have 500,000 children younger than 7 years of age under surveillance. Review of automated screening results from the first 2 years of data revealed a possible increased risk of aseptic meningitis 0 to 14 days after MMR with a relative risk of 3.61 (95% confidence interval, 1.0 to 13.1) although the total number of cases was small. Although the automated data had suggested a possible association of aseptic meningitis with MMR containing the Jeryl-Lynn strain of mumps, review of validated hospitalized cases during the observation period did not reveal evidence of an increased risk of aseptic meningitis after MMR containing the Jeryl-Lynn strain of mumps (odds ratio < 1.0 for all analyses).

CONCLUSION

Although it is recognized that hospitalized cases represent a minority of the total cases of aseptic meningitis, it is reassuring that in this evaluation no increased risk of aseptic meningitis after MMR vaccine was found.

Two novel (M233T and R278T) presenilin-1 mutations in early-onset Alzheimer's disease pedigrees and preliminary evidence for association of presenilin-1 mutations with a novel phenotype

Eleven early-onset dementia families, all with affected individuals who have either presented clinical symptoms of early onset familial Alzheimer's disease (EOFAD) or have been confirmed to have EOFAD by autopsy, and two early onset cases with biopsy-confirmed AD pathology, were screened for missense mutations in the entire coding region of presenilin-1 (PS-1) and -2 (PS-2) genes. Missense mutations were detected by direct sequence analysis of PCR products amplified from genomic DNA templates of affected individuals. Three pedigrees were attributable to known mutations in the PS-1 gene: P264L, E280A and the splice acceptor site (G to T) mutation, which results in the deletion of residues 290-319 of PS-1 (PS-1 delta 290-319). In a fourth pedigree, a novel PS-1 mutation was identified in exon 7 (M233T), which is homologous to a pathogenic PS-2 mutation (M239V), and is characterized by a very early average age of onset (before the age of 35). In one early onset case, another novel PS-1 mutation was identified in exon 8 (R278T). Of the five remaining families and the other early onset case, none have missense mutations in the PS-1 or PS-2 genes, or in exon 16 and 17 of the APP gene. Moreover, two of the PS-1 mutations, PS-1 delta 290-319 and R278T, are associated with the co-presentation of familial spastic paraparesis (FSP) in some of the affected family members. Our data raise the possibility that the phenotypic spectrum associated with PS-1 mutations may extend beyond typical FAD to include FSP, a disease heretofore unsuspected to bear any relationship to FAD. In addition, our data suggest that other novel EOFAD loci, in addition to APP and the presenilin genes, are involved in the aetiology of up to 50% of EOFAD cases.

Arterial injuries in transsphenoidal surgery for pituitary adenoma; the role of angiography and endovascular treatment

PURPOSE

To define the role of angiography and embolization in the treatment of patients who have arterial injuries during transsphenoidal surgery.

METHODS

We retrospectively studied the arterial hemorrhagic complications, their management, and the clinical outcomes that occurred in 21 of the more than 1800 patients who had transsphenoidal surgery for pituitary adenomas.

RESULTS

Of the 21 patients who had complications, 17 had internal carotid injuries and four had injuries of the sphenopalatine artery. Angiography was performed in 18 patients. Bleeding occurred and was controlled during surgery in 16 cases. Delayed epistaxis occurred in 10 patients, including five whose surgery was uneventful. After internal carotid injury, the most frequent angiographic findings were carotid occlusion (eight patients), stenosis (five patients), and false aneurysms (three patients). Internal carotid balloon occlusion was performed in five patients. No rebleeding occurred in patients who had complete carotid occlusion either from surgical packing or balloon embolization. Two of the patients who had carotid stenosis after surgical packing had delayed epistaxis necessitating balloon occlusion. Injuries to the sphenopalatine artery were successfully treated by surgery (one patient) or by endovascular treatment (three patients) without complication. Three deaths and five permanent deficits were directly related to the arterial injury or its treatment.

CONCLUSION

Profuse bleeding during and after transsphenoidal surgery should be investigated by angiography. Lesions of the sphenopalatine arteries are effectively treated by embolization. Internal carotid injuries are best treated by carotid infusion to prevent life-threatening epistaxis.

Amyloid, the presenilins and Alzheimer's disease

Various mutations in the amyloid protein precursor and presenilin genes can lead to early onset, autosomal Alzheimer's disease. A series of mis-sense mutations (with one exception) in each of these genes has been shown to cause disease in a fully penetrant fashion. It has recently been shown, both in vivo and in model systems, that tissues expressing these mutations have increased production of amyloid (A beta) ending at residue 42. It has also recently been shown that this form of A beta is deposited early and selectively in the disease process and is more fibrillogenic in vitro. It is argued that these genetic and molecular biological data provide strong support for the veracity of the 'amyloid cascade hypothesis' for disease pathogenesis, and that this hypothesis offers a coherent framework for drug discovery.

Temporal changes in dynamic inter fragmentary motion and callus formation in fractures

This study examined whether callus proliferation at long bone fractures is triggered by cyclical inter-fragmentary displacement which arises from routine activity. It also examined whether a growing callus increases the stability of a fracture, thereby reducing displacement amplitude during relative motion. Seven tibial fractures stabilised with external fixators were monitored up to and beyond fixator removal. An instrumented spatial linkage was developed which was attached to the bone screws to measure inter-fragmentary displacement at the fracture in all six degrees of freedom during routine walking. Callus index (final bone width/initial bone width) was measured at the posterior and lateral cortical surfaces from orthogonal radiographs. In all seven subjects, callus growth was initiated subsequent to a peak in displacement which occurred within the first 42 days; at nine of the 14 surfaces occurred callus initiation occurred within 14 days of the peak displacement. With the exception of two lateral surfaces, maximum callus size, subsequent to fixator removal (at up to 119 days after removal). Displacement reduced during callus growth in five out of six subjects. Since the reduction in displacement did not arise from reduced weight-bearing, increasing callus size must correlate with progressive mechanical union. This was confirmed by end point stiffness tests. Therefore, peak cyclical displacement appears to be the stimulus for callus growth, the effect of which is to reduce displacement and strain which allows the following stages of bone formation and remodelling to unite the fracture.