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Biomedical subjects

G Wilcock

Publications and source records attributed to G Wilcock.

At least 19 recordsLinked to original sources
PubMed2005

Contributors to white matter damage in the frontal lobe in Alzheimer's disease.

Abnormalities of cerebral white matter are present in a majority of patients with Alzheimer's disease (AD) and probably contribute to motor dysfunction and cognitive impairment. The white matter abnormalities are usually attributed to degenerative vascular disease and cerebral amyloid angiopathy (CAA) but the evidence is scanty or inconclusive. In the present study we examined sections of frontal lobe from 125 autopsy-confirmed cases of AD and assessed the relationship of degenerative large and small vessel disease, CAA, parenchymal Abeta load and APOE genotype, to several objective measures of white matter damage: extent of immunolabelling for glial fibrillary acidic protein (GFAP), axonal accumulation of amyloid precursor protein (APP), axon density in superficial and deep white matter, and intensity of staining for myelin. We found no association between atherosclerosis, arteriolosclerosis, CAA or APOE genotype and white matter damage. However, labelling of white matter for GFAP correlated strongly with the parenchymal Abeta load (P = 0.0003) and with APP accumulation (P = 0.008). Our findings suggest that severity of frontal white matter damage in AD is closely related to parenchymal Abeta load and that in most cases the contribution of degenerative vascular disease, CAA and APOE is relatively minor.

Alzheimer Disease↗
PubMed2004

Long-term efficacy and safety of galantamine in patients with mild-to-moderate Alzheimer's disease: multicenter trial.

In clinical trials, short-term galantamine treatment produces consistent positive effects on global ratings, cognitive tests, and assessments of activities of daily living and behavior in patients with mild-to-moderate Alzheimer's disease (AD), providing the rationale for longer-term, open-label treatment. In this continuation trial following enrollment in previous 12-month trials, patients received galantamine 24 mg/day for a total of 24 months (total exposure up to 36 months). Primary efficacy measures were the ADAS-cog/11 and DAD. Adverse events (AEs) were coded to WHO preferred terms, including AEs begun in previous trials. Initial improvement in cognitive function was followed by a gradual decline, as measured by increased ADAS-cog/11 scores. At 36 months, ADAS-cog/11 scores increased by a mean (SEM) of 12.4 (0.80) points (P < 0.001) versus a projected 22-point increase for untreated patients. Functional abilities, as measured by the DAD, had decreased significantly at each time point versus baseline (P < 0.001). The most common treatment-emergent AEs were agitation (16.1%), insomnia (12.4%), fall (11.2%), and urinary tract infection (10.2%). AEs were mainly mild to moderate, appropriate for an elderly population, with few judged treatment related. Galantamine 24 mg/day is safe and effective for long-term treatment of mild-to-moderate AD. Potential exists for prolonged benefit with galantamine therapy versus lack of treatment for the long-term.

Aged↗
PubMed2003

Neuropsychological prediction of conversion to dementia from questionable dementia: statistically significant but not yet clinically useful.

BACKGROUND: Verbal memory impairment, one of the earliest signs of Alzheimer's disease (AD), may help identify people with cognitive impairment, insufficient for a diagnosis of dementia (questionable dementia: QD), at risk of developing AD. Other cognitive parameters have been found that may indicate which people with QD will go on to develop dementia. Nevertheless, some researchers have reported only partial success in differentiating between mild AD and age related cognitive impairment. OBJECTIVES: To discover if there are early, pre-clinical cognitive markers that could help identify patients attending our memory clinic who were at risk of developing dementia. METHODS: Multidisciplinary assessment of a consecutive sample of 195 patients with QD seen in a National Health Service hospital outpatient clinic; 135 seen for a mean follow up of 24.5 months. RESULTS: Conversion rate to dementia was 27.4% (37 of 135). A diagnosis of probable or possible AD was made in 15.6% (21 of 135) of cases. Despite statistically significant differences in some cognitive tasks between those who did and those who did not go on to dement, Cox regression analyses failed to improve prediction rates markedly above base rates and were unstable. CONCLUSION: A large number of studies claim good prediction of conversion to dementia using cognitive test scores. Although this study produced similarly good sensitivity and specificity values, proper consideration of the statistical analyses and their clinical significance suggested that these prediction methods are currently too imprecise for clinical use. Use of cognitive indicators combined with neuroradiological, neuropathological, and genetic factors for predicting conversion to dementia might prove more reliable but may be beyond the scope of many geriatric services.

Aged↗
PubMed2002

A double-blind, placebo-controlled multicentre study of memantine in mild to moderate vascular dementia (MMM500).

The aim of the reported trial was to investigate the safety and efficacy of memantine in mild to moderate vascular dementia (VaD). This was a 28-week, double-blind, parallel, randomized controlled trial of memantine 20 mg daily versus placebo which was conducted in 54 centres in the UK. Memantine is a uncompetitive, moderate affinity N-methyl-D-aspartate receptor antagonist. Patients with a diagnosis of probable VaD and Mini Mental State Examination total scores between 10 and 22 were eligible for inclusion. Primary efficacy parameters were the Alzheimer's Disease Assessment Scale-Cognitive Subscale (ADAS-cog) and the Clinical Global Impression of Change (CGI-C). A total of 579 patients were randomized and 548 patients with at least one post-baseline efficacy assessment qualified for the intent-to-treat analysis. At endpoint, memantine was shown to improve cognition relative to placebo in VaD: the change of ADAS-cog from baseline differed by a mean of -1.75 points (95% confidence intervals -3.023 to -0.49) and a median of 2 points between the two groups, while CGI-C ratings showed no significant differences between treatment groups. A total of 77% of all memantine-treated patients experienced adverse event, versus 75% of the placebo-treated patients, dizziness being the most frequent adverse event (11% versus 8%, respectively). Memantine was well tolerated and safe.

Aged↗
PubMed2000

Association of interleukin-1 gene polymorphisms with Alzheimer's disease.

Interleukin-1 (IL-1) is markedly overexpressed in Alzheimer's disease. We found the IL-1A 2,2 genotype in 12.9% of 232 neuropathologically confirmed Alzheimer's disease patients and 6.6% of 167 controls from four centers in the United Kingdom and United States (odds ratio, 3.0; controlled for age and for ApoE [apolipoprotein E] genotype). Homozygosity for both allele 2 of IL-1A and allele 2 of IL-1B conferred even greater risk (odds ratio, 10.8). IL-1 genotypes may confer risk for Alzheimer's disease through IL-1 overexpression and IL-1-driven neurodegenerative cascades.

Aged↗
PubMed1998

Cholinesterase inhibition for Alzheimer disease: a meta-analysis of the tacrine trials. Dementia Trialists' Collaboration.

OBJECTIVES: To determine the effects of cholinesterase inhibition with tacrine hydrochloride for the symptoms of Alzheimer disease in terms of cognitive performance, clinical global impression, behavior, and functional autonomy. DATA SOURCES: The Cochrane Dementia Group registry of trials. STUDY SELECTION: Unconfounded, randomized, double-blind, placebo-controlled trials in which tacrine had been given for more than 1 day and that were completed before January 1, 1996. DATA EXTRACTION: Two reviewers independently selected trials for inclusion and individual patient data were sought. DATA SYNTHESIS: Data were analyzed from 12 trials that included 1984 patients with Alzheimer disease. At 12 weeks, cognitive performance, as measured by the Mini-Mental State Examination (score range, 0-30), was better in patients receiving tacrine than in patients receiving placebo by 0.62 points (95% confidence interval [CI], 0.23-1.00; P=.002). Compared with similar untreated patients who would be expected to deteriorate by 0.50 to 1.00 points on the Mini-Mental State Examination during 12 weeks, the progress of patients receiving tacrine would be expected to range between an improvement of 0.12 and a deterioration of 0.38 points. The odds ratio for improvement on the Clinical Global Impression of Change scale (range, 1-7) for patients receiving tacrine compared with those receiving placebo was 1.58 (95% CI, 1.18-2.11; P=.002). The behavioral noncognitive subscale of the Alzheimer's Disease Assessment Scale (range, 0-50) showed a difference in favor of tacrine of 0.58 points (95% CI, 0.17-1.00; P= .006). Improvement on the Progressive Deterioration Scale, largely an index of functional activities, was not significant (0.75; 95% CI, -0.43 to 1.93; P=.21). Age, severity of dementia, and exposure to tacrine prior to randomization had no clear influence on the treatment effect. There was a nonsignificant trend toward increasing effect with increasing dose for cognitive function and the Clinical Global Impression of Change. For patients without prior exposure to tacrine, the odds of patients' withdrawing during the study while they were receiving tacrine compared with placebo was 3.63 (95% CI, 2.80- 4.71; P<.001). Eleven (95% CI, 7-31) patients would need to be treated to achieve any improvement on the Clinical Global Impression scale, and 42 (95% CI, 23-125) to achieve a moderate or marked improvement. One patient would be expected to withdraw for every 4 (95% CI, 3-5) patients treated. CONCLUSIONS: Cholinesterase inhibition with tacrine appears to reduce deterioration in cognitive performance during the first 3 months and increase the odds of global clinical improvement. Effects observed on measures of behavioral disturbance were of questionable clinical significance, and functional autonomy was not significantly affected. The clinical relevance of the benefits of cholinesterase inhibition remains controversial, and long-term trials with clinically relevant end points are required.

Alzheimer Disease↗
PubMed1998

Are genetic factors important in the aetiology of leukoaraiosis? Results from a memory clinic population.

OBJECTIVE: To discover whether polymorphism in either the apolipoprotein E (ApoE) or angiotensin-converting enzyme (ACE) genes is associated with leukoaraiosis, white matter lesions visible on neuroimaging of the brain, which is commonly seen in dementia as well as some normal elderly subjects. DESIGN: Prospective study of consecutive patients attending our memory disorders clinic, to examine the relationship between leukoaraiosis and polymorphism of the ApoE and ACE genes. SETTING: Memory disorders clinic in Bristol, UK. PATIENTS: 182 patients attending the memory disorders clinic for investigation of possible dementia of whom 75% were suffering from dementia, 20% from memory impairment but no dementia and in 5% of whom a dementing illness was thought to be unlikely; 38% of all patients had visible white matter lesions and 16% had cerebral infarcts. MEASURES: Patients and/or carers who agreed to participate in the study had their ACE and ApoE genotype determined and their brain CT/MRI scans were assessed by a neuroradiologist, blind to the result of the genotyping, for the presence or absence of white matter low attenuation. RESULTS: There was a significant association between white matter lesions and the DD genotype (p < 0.05), but not the ApoE genotype. However, this relationship with the DD genotype was only significant for patients with a previous infarct. CONCLUSION: Homozygosity of ACE gene deletion polymorphism is a risk factor for white matter lesions when it is associated with cerebral infarction. This suggests that it may be possible to identify subjects who are at greater risk of developing white matter lesions and are at risk of cognitive impairment and possibly dementia.

Aged↗
PubMed1998

A presenilin-1 truncating mutation is present in two cases with autopsy-confirmed early-onset Alzheimer disease.

We have examined genomic DNA from 40 cases of autopsy-confirmed early-onset Alzheimer disease (EOAD) (age at onset <=65 years) that were all unselected for family history. We have sequenced the 10 exons and flanking intronic sequences of the presenilin-1 (PS-1) gene for all 40 individuals. A single mutation, a deletion of a G from the intron 4 splice-donor consensus sequence, was detected in two individuals in this study. The mutation was associated with two shortened transcripts, both with shifted reading frames resulting in premature-termination codons. All the PS-1 mutations described elsewhere have been missense or in-frame splice mutations, and recent data suggest that these result in disease by gain-of-function or dominant-negative mechanisms. The mutation that we have identified is likely to result in haploinsufficiency and would be most consistent with other mutations acting in a dominant-negative manner. However, we cannot exclude the possibility that the small amounts of truncated transcripts exert a gain of function. Since no other mutations or polymorphisms were detected in our patients, mutations in the coding regions and splice consensus sequences of PS-1 are likely to be rare in EOAD cases unselected for family history.

Adult↗
PubMed1998

Placement of dementia sufferers in residential and nursing home care.

BACKGROUND: Few UK studies have examined the associations of residential or nursing home placement in dementia sufferers. METHOD: 124 patients with mild to moderate dementia (according to the Diagnostic and Statistical Manual of Mental Disorders, third edition, revised) and in contact with clinical services were evaluated with a detailed standardized assessment and followed-up at monthly intervals for 1 year. RESULTS: 25 (21.6%) of the 116 patients living at home were admitted to residential or nursing home care during the follow-up year. Institutional placement was associated with greater severity of cognitive impairment, severity of parkinsonism and the failure of carers to adopt active coping strategies. CONCLUSION: An intervention to improve coping skills in carers may decrease the rates of residential and nursing home placement.

Aged↗
PubMed1998

The butyrylcholinesterase K variant and susceptibility to Alzheimer's disease.

Previous work has shown an association between the K variant of the butyrylcholinesterase (BCHE) gene and Alzheimer's disease (AD) in patients carrying the epsilon4 allele of ApoE. We attempted to replicate this finding in 181 UK white AD cases and 71 controls. No difference was found in BCHE-K genotypes (p=0.75) or alleles (p=0.70) between patients and controls. Moreover, despite a significant excess of ApoE epsilon4 in patients versus controls (p<0.0001), we found no evidence to support previous reports of an interaction between ApoE and BCHE-K (chi2=1.49, df=4, p=0.83).

Aged↗
PubMed1998

Formal consensus and consultation: a qualitative method for development of a guideline for dementia.

OBJECTIVES: To use a formal consensus method--the nominal group technique--for developing a clinical practice guideline to improve the diagnosis, needs assessment, and management of dementia at the primary/secondary care interface. To assess the usefulness of this method in an area where there is a dearth of clinical trials thus precluding an evidence-based approach. DESIGN: A qualitative and iterative method was used. The guideline was developed by an expert panel using the nominal group technique, incorporating the deliberations of a Primary Care Professionals' Task Group, recent reviews in the scientific literature, information from semistructured interviews with local specialists, and a local questionnaire survey. SETTING: Mainly Bristol but incorporating other parts of the United Kingdom especially the south and west. SUBJECTS: Expert panel group (including users and non-statutory organisations), local general practitioners (GPs), professionals carrying out the health check for people over 75, local geriatricians and psychogeriatricians, and primary care professionals with an interest in dementia. MAIN MEASURES: Items important in dementia from the nominal group in response to three questions on diagnosis, needs assessment, and management, ranked into a series of top 10 items for each area and allocated a score according to relative importance to each member; summary outputs from the questionnaire survey, semistructured interviews, and primary care professionals' task group. RESULTS: A clinical practice guideline covering diagnosis, needs assessment, and management of dementia in primary care was produced in the form of an algorithm and a management sheet. CONCLUSIONS: A formal consensus method can be used as an acceptable alternative to the evidence-based approach when developing guidelines in situations in which evidence is scarce, in which the guideline is intended as an aid in linking different stages of care, and in which practical and political considerations--such as the links between agencies--are important.

Consensus Statements as Topic↗
PubMed1997

Presenilin-1 intron 8 polymorphism is not associated with autopsy-confirmed late-onset Alzheimer's disease.

Mutations in the presenilin-1 (PS-1) gene may account for the majority of familial early-onset Alzheimer's disease (EOAD) cases. However, there is controversy as to whether the bi-allelic intron 8 PS-1 polymorphism plays a role in late-onset AD (LOAD). As previous association studies with this polymorphism have all investigated clinically diagnosed LOAD cases, we have analysed the frequency of the PS-1 intronic polymorphism in a series of autopsy-confirmed early- (n = 54) and late-onset (n = 199) cases and a large control population of non-demented, aged individuals (n = 215). Our sample size should have had the power to reveal effects of the size previously reported for the PS-1 polymorphism, but we detected no significant increase in the 1/1 risk genotype distribution in EOAD or LOAD cases. Thus, we have been unable to find an association between the PS-1 intronic polymorphism and early- or late-onset AD within this autopsy-confirmed population.

Age of Onset↗
PubMed1997

A prospective study of psychotic symptoms in dementia sufferers: psychosis in dementia.

Eighty-seven out of a clinical cohort of 124 patients with Diagnostic and Statistical Manual of Mental Disorders (3rd ed., rev.) dementia were followed up at monthly intervals for 1 year. Psychotic symptoms were assessed using the Burns's Symptom Checklist, and cognitive functioning was evaluated with the CAMCOG. The annual incidence rate of psychotic symptoms was 47%, although many of the incident symptoms lasted less than 3 months. Fifty-three percent of patients with psychosis experienced resolution of their symptoms. Patients either experienced brief or persistent psychotic disorders, with few having an intermediary course. Persistent psychosis was significantly associated with a 3-month duration of symptoms at baseline. Neuroleptics did not significantly influence the course of psychotic symptoms.

Aged↗