Telephone Interview for Cognitive Status Scores Associate with Cognitive Impairment and Alzheimer's Disease Pathology at Death

BACKGROUND

Early diagnosis of Alzheimer's disease (AD) provides an opportunity for early intervention. Cognitive testing has proven to be a reliable way to identify individuals who may be at risk of AD. The Telephone Assessment for Cognitive Screening (TICS) is proficient in screening for cognitive impairment. However, its ability to identify those at risk of developing AD pathology is unknown.

OBJECTIVE

We aim to investigate associations between TICS scores, collected over a period of 13 years, and the cognitive status of participants at death. We also examine relationships between TICS scores and neuropathological indices of AD (CERAD score, Thal phase, and Braak stage).

METHODS

Between 2004 and 2017, participants from The University of Manchester Longitudinal Study of Cognition in Normal Healthy Old Age underwent cognitive assessment using TICS. Scores from four time points were available for analysis. Cognitive impairment and AD pathology at death was evaluated in 101 participants.

RESULTS

TICS scores at time points 2, 3, and 4 were significantly lower in those cognitively impaired at death compared to those considered cognitively normal. There were significant negative correlations between TICS scores and CERAD score and Braak stage at time points 2 and 4. No correlations between Thal phase and TICS were found.

CONCLUSION

Findings indicate that TICS could be used not only to screen for cognitive impairment, but also to identify individuals at risk of developing AD pathology, many years before any overt symptoms occur. Once identified, 'at risk' individuals could be targeted for early interventions which could attenuate the progression of the disease.

The Contribution of Vascular Pathology Toward Cognitive Impairment in Older Individuals with Intermediate Braak Stage Tau Pathology

BACKGROUND

The pathological features of Alzheimer's disease (AD) are well described but little is known as to how both neurodegeneration and vascular changes might interact in causing cognitive impairment.

OBJECTIVE

The present study aims to investigate relationships between vascular and AD pathology in cognitively healthy and cognitively impaired individuals with a particular emphasis on those at intermediate Braak tau stages.

METHODS

We investigated the interplay between Braak tau stage and measures of vascular pathology as described by the vascular cognitive impairment neuropathology guidelines (VCING) in 185 brains from the Brains for Dementia Research programme and The University of Manchester Longitudinal Study of Cognition in Healthy Old Age. VCING asserts that at least one large (>10 mm) infarct, moderate/severe occipital leptomeningeal cerebral amyloid angiopathy, and moderate/severe arteriosclerosis in occipital white matter accurately predicts the contribution of cerebrovascular pathology to cognitive impairment.

RESULTS

We found that the extent of arteriosclerosis in the occipital white matter did not differ between cognitive groups at intermediate (III-IV) Braak stages whereas moderate/severe leptomeningeal occipital cerebral amyloid angiopathy was greater in cognitively impaired than normal individuals at Braak stage III-IV. This finding remained significant after controlling for effects of age, sex, CERAD score, Thal phase, presence/severity of primary age-related tauopathy, presence/severity of limbic-predominant age-related TDP43 encephalopathy and small vessel disease in basal ganglia.

CONCLUSION

Interventions targeting cerebral amyloid angiopathy may contribute to delay the onset of cognitive impairment in individuals with intermediate Alzheimer's type pathology.

Mid to late-life scores of depression in the cognitively healthy are associated with cognitive status and Alzheimer's disease pathology at death

OBJECTIVES

Early diagnosis of Alzheimer's disease (AD) is essential for early interventions. Symptoms of depression could represent a prodromal stage of AD. Very early mood alterations may help to stratify those at highest risk of late-life AD. We aim to investigate associations between baseline/longitudinal scores for depression, presence of cognitive impairment and/or AD pathology at death.

METHODS/DESIGN

Between 1991 and 2015, participants from The University of Manchester Longitudinal Study of Cognition in Normal Healthy Old Age underwent 10 waves of assessment using the Geriatric Depression Scale (GDS). AD pathology at death was evaluated in 106 eligible cases. Analyses aimed to examine associations between GDS scores, cognitive status and AD pathology (as measured by Braak stage, Thal phase and CERAD).

RESULTS

Baseline GDS scores were significantly higher for those cognitively impaired at death than those cognitively normal. Significantly higher baseline GDS scores were found for those with greater Consortium to Establish a Registry for Alzheimer's Disease (CERAD) scores than those with lower CERAD scores. Similarly, significantly higher baseline GDS scores were found for those with a greater Braak stage than those with lower tau burden. These correlations remained after controlling for age at death, education and APOE ε4, but were less robust. Mean longitudinal GDS scores associated with cognition but not pathology.

CONCLUSIONS

GDS scores collected approximately 20 years before death were associated with cognitive status and AD pathology at death. We postulate that early AD-related pathological change produces raised GDS scores due to an overlapping neural basis with depression, and that this may be considered as an early diagnostic marker for AD.

A Comparative Study of Pathological Outcomes in The University of Manchester Longitudinal Study of Cognition in Normal Healthy Old Age and Brains for Dementia Research Cohorts

In the present study, we have characterized and compared individuals whose brains were donated as part of The University of Manchester Longitudinal Study of Cognition in Normal Healthy Old Age (UoM) with those donated through the Manchester arm of the UK Brains for Dementia Research (BDR) program. The aim of this study was to investigate how differences in study recruitment may affect final pathological composition of cohort studies. The UoM cohort was established as a longitudinal study of aging and cognition whereas the BDR program was established, prima facie, to collect brains from both demented and non-demented individuals for the purpose of building a tissue research resource. Consequently, the differences in recruitment patterns generated differences in demographic, clinical, and neuropathological characteristics. There was a higher proportion of recruits with dementia [mostly Alzheimer's disease (AD)] within the BDR cohort than in the UoM cohort. In pathological terms, the BDR cohort was more 'polarized', being more composed of demented cases with high Braak pathology scores and non-demented cases with low Braak scores, and fewer non-AD pathology cases, than the UoM cohort. In both cohorts, cerebral amyloid angiopathy tended to be greater in demented than non-demented individuals. Such observations partly reflect the recruitment of demented and non-demented individuals into the BDR cohort, and also that insufficient study time may have elapsed for disease onset and development in non-demented individuals to take place. Conversely, in the UoM cohort, where there had been nearly 30 years of study time, a broader spread of AD-type pathological changes had 'naturally' evolved in the brains of both demented and non-demented participants.

Influence of APOE Genotype on Mortality and Cognitive Impairment

While many studies have examined the associations between APOE genotype and mortality, findings have often been conflicting and it remains unclear whether APOE genotype affects longevity. Using selected individuals from the Manchester arm of the Brains for Dementia Research programme and University of Manchester Longitudinal Study of Cognition in Normal Healthy Old Age, we investigated relationships between APOE genotype and age at death in both cognitively normal and cognitively impaired individuals. Results indicated that carrying the APOE ɛ4 allele led to a reduced chance in an individual reaching 80+ years and remaining cognitively healthy. Conversely, APOE ɛ2 carriers tended to live longer and remain cognitively normal. These findings add to the evidence that APOE genotype influences longevity, especially in cognitively impaired individuals who carry the APOE ɛ4 allele.

No association between head injury with loss of consciousness and Alzheimer disease pathology-Findings from the University of Manchester Longitudinal Study of Cognition in Normal Healthy Old Age

OBJECTIVES

Head injury with loss of consciousness (HI-LOC) is a common occurrence. Some studies have linked such injuries with an increased risk of Alzheimer disease (AD). However, recent large clinicopathologic studies have failed to find a clear relationship between HI-LOC and the pathological changes associated with AD. The present study aims to further investigate the relationship between HI-LOC and AD pathology in the elderly.

METHODS/DESIGN

History of HI-LOC in participants in the University of Manchester Longitudinal Study of Cognition in Normal Healthy Old Age was ascertained. The donated brains of 110 of these individuals were assessed for AD pathology using consensus guidelines. Analyses aimed to elucidate relationships between HI-LOC and AD pathology.

RESULTS

No associations were found between incidence of HI-LOC and regional AD pathology or any of the three established measures of the neuropathology associated with AD: CERAD score, Thal phase, or Braak stage.

CONCLUSIONS

Single incidences of HI-LOC may not be sufficient to cause the pathology associated with late-stage AD. Other routes of damage, such as diffuse axonal injury or Lewy body pathology, may play a greater role in causing cognitive impairment associated with head injury.

Scores Obtained from a Simple Cognitive Test of Visuospatial Episodic Memory Performed Decades before Death Are Associated with the Ultimate Presence of Alzheimer Disease Pathology

BACKGROUND

Community- or population-based longitudinal studies of cognitive ability with a brain donation end point offer an opportunity to examine relationships between pathology and cognitive state prior to death. Discriminating the earliest signs of dementing disorders, such as Alzheimer disease (AD), is necessary to undertake early interventions and treatments.

METHODS

The neuropathological profile of brains donated from The University of Manchester Longitudinal Study of Cognition in Normal Healthy Old Age, including CERAD (Consortium to Establish a Registry for Alzheimer's Disease) and Braak stage, was assessed by immunohistochemistry. Cognitive test scores collected 20 years prior to death were correlated with the extent of AD pathology present at death.

RESULTS

Baseline scores from the Memory Circle test had the ability to distinguish between individuals who developed substantial AD pathology and those with no, or low, AD pathology. Predicted test scores at the age of 65 years also discriminated between these pathology groups. The addition of APOE genotype further improved the discriminatory ability of the model.

CONCLUSIONS

The results raise the possibility of identifying individuals at future risk of the neuropathological changes associated with AD over 20 years before death using a simple cognitive test. This work may facilitate early interventions, therapeutics and treatments for AD by identifying at-risk and minimally affected (in pathological terms) individuals.

On the Fibrinolytic System in Aged Rats, and Its Reactivity to Endotoxin and Cytokines

Aged rats are more susceptible to endotoxin-induced effects, including microthrombosis and platelet aggregation, than are young rats. To investigate whether changes in the fibrinolytic system might be involved, we investigated the fibrinolytic activity in plasma euglobulin fractions and tissues (lung and heart) of young (6-months old) and aged (24-months old) rats under baseline conditions and after challenge with endotoxin. Aged rats had lower plasma levels of tissue-type plasminogen activator (t-PA) and of urokinase-type PA (u-PA) activity. PA inhibitor (PAI) activity was higher in the plasma of aged rats, as was t-PA activity in lung and heart.

Rats were treated with either a low dose (1 μg/kg) or a high dose (10 mg/kg) of endotoxin. Both treatments induced a transient phase of increased blood fibrinolytic activity, as evidenced by higher levels of tissue-type plasminogen activator (t-PA) activity and decreased levels of PA inhibitor (PAI) activity. Over time, the fibrinolytic activity decreased, probably due to increased levels of PA inhibitor.

Both the early increase in t-PA activity, and the subsequent increase in PAI activity, were more pronounced in the aged rats, as compared with the younger rats, after the high dose of endotoxin. The aged rats also responded to an injection of interleukin-1β or tumor necrosis factor-α with a larger increase of PAI activity than did the younger rats.

Together the data suggest that, compared to young rats, aged rats have a decreased base-line plasma fibrinolytic activity, while their fibrinolytic system is more responsive to challenge by endotoxin and cytokines.

Genome-wide association study identifies 74 loci associated with educational attainment

Educational attainment is strongly influenced by social and other environmental factors, but genetic factors are estimated to account for at least 20% of the variation across individuals. Here we report the results of a genome-wide association study (GWAS) for educational attainment that extends our earlier discovery sample of 101,069 individuals to 293,723 individuals, and a replication study in an independent sample of 111,349 individuals from the UK Biobank. We identify 74 genome-wide significant loci associated with the number of years of schooling completed. Single-nucleotide polymorphisms associated with educational attainment are disproportionately found in genomic regions regulating gene expression in the fetal brain. Candidate genes are preferentially expressed in neural tissue, especially during the prenatal period, and enriched for biological pathways involved in neural development. Our findings demonstrate that, even for a behavioural phenotype that is mostly environmentally determined, a well-powered GWAS identifies replicable associated genetic variants that suggest biologically relevant pathways. Because educational attainment is measured in large numbers of individuals, it will continue to be useful as a proxy phenotype in efforts to characterize the genetic influences of related phenotypes, including cognition and neuropsychiatric diseases.

Predicting cognitive ability in ageing cohorts using Type 2 diabetes genetic risk

AIMS

To investigate whether there is overlap in the genetic determinants of Type 2 diabetes and cognitive ageing by testing whether a genetic risk score for Type 2 diabetes can predict variation in cognitive function in older people without dementia.

METHODS

Type 2 diabetes genetic risk scores were estimated using various single nucleotide polymorphism significance inclusion criteria from an initial genome-wide association study, the largest in Type 2 diabetes to date. Scores were available for 2775-3057 individuals, depending on the cognitive trait.

RESULTS

Type 2 diabetes genetic risk was associated with self-reported diabetes mellitus. Across varying single nucleotide polymorphism-inclusion levels, a significant association between Type 2 diabetes genetic risk and change in general cognitive function was found (median r = 0.04); however, this was such that higher Type 2 diabetes genetic risk related to higher cognitive scores.

CONCLUSIONS

To investigate more fully the source of the often observed comorbidity between Type 2 diabetes and cognitive impairment, one direction for future research will be to use cognitive ability polygenic risk scores to predict Type 2 diabetes in line with the reverse causation hypothesis that people with lower pre-morbid cognitive ability are more likely to develop Type 2 diabetes.

Genome-wide association study meta-analysis of chronic widespread pain: evidence for involvement of the 5p15.2 region

BACKGROUND AND OBJECTIVES

Chronic widespread pain (CWP) is a common disorder affecting ∼10% of the general population and has an estimated heritability of 48-52%. In the first large-scale genome-wide association study (GWAS) meta-analysis, we aimed to identify common genetic variants associated with CWP.

METHODS

We conducted a GWAS meta-analysis in 1308 female CWP cases and 5791 controls of European descent, and replicated the effects of the genetic variants with suggestive evidence for association in 1480 CWP cases and 7989 controls. Subsequently, we studied gene expression levels of the nearest genes in two chronic inflammatory pain mouse models, and examined 92 genetic variants previously described associated with pain.

RESULTS

The minor C-allele of rs13361160 on chromosome 5p15.2, located upstream of chaperonin-containing-TCP1-complex-5 gene (CCT5) and downstream of FAM173B, was found to be associated with a 30% higher risk of CWP (minor allele frequency=43%; OR=1.30, 95% CI 1.19 to 1.42, p=1.2×10(-8)). Combined with the replication, we observed a slightly attenuated OR of 1.17 (95% CI 1.10 to 1.24, p=4.7×10(-7)) with moderate heterogeneity (I2=28.4%). However, in a sensitivity analysis that only allowed studies with joint-specific pain, the combined association was genome-wide significant (OR=1.23, 95% CI 1.14 to 1.32, p=3.4×10(-8), I2=0%). Expression levels of Cct5 and Fam173b in mice with inflammatory pain were higher in the lumbar spinal cord, not in the lumbar dorsal root ganglions, compared to mice without pain. None of the 92 genetic variants previously described were significantly associated with pain (p>7.7×10(-4)).

CONCLUSIONS

We identified a common genetic variant on chromosome 5p15.2 associated with joint-specific CWP in humans. This work suggests that CCT5 and FAM173B are promising targets in the regulation of pain.

Effect of dietary fish oil supplementation on fever and cytokine production in human volunteers

The effect of dietary fish oil supplementation on acute phase responses to intramuscular injection of typhoid vaccine, and in vitro cytokine production, was investigated in human volunteers. Half of the subjects supplemented their normal diet with 4.5 g/day of fish oil for 6-8 weeks. Injection of typhoid vaccine in unsupplemented subjects caused an increase in white cell count, resting heart rate, metabolic rate, oxygen consumption, and oral temperature. Fish oil supplementation inhibited the tachycardia and attenuated the maximal increases in oral temperature and metabolic rate following typhoid vaccine. However, interpretation of these latter results were complicated by similarly attenuated responses in saline-injected subjects. The in vitro production of interleukin-1 and interleukin-6 from whole blood was suppressed by fish oil supplementation, however, production of tumor necrosis factor alpha was not significantly altered. Fish oil supplementation may therefore provide a non-pharmacological approach of attenuating several of the responses associated with injury and infection and this may be related to reduced cytokine (IL-1 and IL-6) production.

The non-synonymous SNP, R1150W, in SCN9A is not associated with chronic widespread pain susceptibility

Background

Mutations in SCN9A, encoding the alpha subunit of the voltage-gated sodium channel (Na_v1.7), have caused severe pain disorders and congenital insensitivity to pain. The aim of this study was to validate the previously reported association between a common non-synonymous polymorphism (R1150W, rs6746030) in SCN9A and chronic widespread pain (CWP), in independent population-based cohorts.

Findings

Genotype data for rs6746030 was available in four population-based cohorts (EPIFUND, the European Male Ageing Study (EMAS), the Framingham study and the Dyne Steel DNA Bank of Ageing and Cognition). Pain was assessed using body manikins and CWP was scored using American College of Rheumatology (ACR) criteria in all cohorts, except the Framingham study which assessed widespread pain (WP) using ACR criteria on a joint pain homunculus. Controls were subjects who reported no pain. Logistic regression (additive genetic model) was used to test for association between rs6746030 and CWP compared to controls, adjusting for study centre in EMAS. Generalised estimating equation regression was used to test for association between rs6746030 and WP, whilst accounting for relatedness between subjects in the Framingham study.

Genotype data for rs6746030 was available for 1071 CWP cases and 3212 controls. There was no significant association between CWP and rs6476030 in individual cohorts or when combined in a fixed-effects meta-analysis (Odds Ratio = 0.96 (95% confidence interval 0.82, 1.11) p = 0.567).

Conclusions

In contrast to a previous study, no association between a non-synonymous polymorphism in SCN9A and CWP was observed in multiple population-based cohorts.

The role of ECE1 variants in cognitive ability in old age and Alzheimer's disease risk

The β-amyloid peptide may play a central role in Alzheimer's disease (AD) pathogenesis. We have evaluated variants in seven Aβ-degrading genes (ACE, ECE1, ECE2, IDE, MME, PLAU, and TF) for association with AD risk in the Genetic and Environmental Risk in Alzheimer's Disease Consortium 1 (GERAD1) cohort, and with three cognitive phenotypes in the Lothian Birth Cohort 1936 (LBC1936), using 128 and 121 SNPs, respectively. In GERAD1, we identified a significant association between a four-SNP intragenic ECE1 haplotype and risk of AD in individuals that carried at least one APOE ε4 allele (P = 0.00035, odds ratio = 1.61). In LBC1936, we identified a significant association between a different two-SNP ECE1 intragenic haplotype and non-verbal reasoning in individuals lacking the APOE ε4 allele (P = 0.00036, β = -0.19). Both results showed a trend towards significance after permutation (0.05 < P < 0.10). A follow-up cognitive genetic study evaluated the association of ECE1 SNPs in three additional cohorts of non-demented older people. Meta-analysis of the four cohorts identified the significant association (Z < 0.05) of SNPs in the ECE-1b promoter with non-verbal reasoning scores, particularly in individuals lacking the APOE ε4 allele. Our genetic findings are not wholly consistent. Nonetheless, the AD associated intronic haplotype is linked to the 338A variant of known ECE1b promoter variant, 338C>A (rs213045). We observed significantly less expression from the 338A variant in two human neuroblastoma cell lines and speculate that this promoter may be subject to tissue-specific regulation.

Genome-wide association uncovers shared genetic effects among personality traits and mood states

Measures of personality and psychological distress are correlated and exhibit genetic covariance. We conducted univariate genome-wide SNP (~2.5 million) and gene-based association analyses of these traits and examined the overlap in results across traits, including a prediction analysis of mood states using genetic polygenic scores for personality. Measures of neuroticism, extraversion, and symptoms of anxiety, depression, and general psychological distress were collected in eight European cohorts (n ranged 546-1,338; maximum total n = 6,268) whose mean age ranged from 55 to 79 years. Meta-analysis of the cohort results was performed, with follow-up associations of the top SNPs and genes investigated in independent cohorts (n = 527-6,032). Suggestive association (P = 8 × 10(-8)) of rs1079196 in the FHIT gene was observed with symptoms of anxiety. Other notable associations (P < 6.09 × 10(-6)) included SNPs in five genes for neuroticism (LCE3C, POLR3A, LMAN1L, ULK3, SCAMP2), KIAA0802 for extraversion, and NOS1 for general psychological distress. An association between symptoms of depression and rs7582472 (near to MGAT5 and NCKAP5) was replicated in two independent samples, but other replication findings were less consistent. Gene-based tests identified a significant locus on chromosome 15 (spanning five genes) associated with neuroticism which replicated (P < 0.05) in an independent cohort. Support for common genetic effects among personality and mood (particularly neuroticism and depressive symptoms) was found in terms of SNP association overlap and polygenic score prediction. The variance explained by individual SNPs was very small (up to 1%) confirming that there are no moderate/large effects of common SNPs on personality and related traits.

Clinical correlates of cerebral white matter hyperintensities in cognitively normal older adults

Many research studies have demonstrated asymptomatic white matter hyperintensities (WMHs) in older adults, which are postulated to be ischemic in origin. We hypothesized that certain clinical predictors, measured in a population of healthy older adults, would have a positive relationship with WMH scoring on magnetic resonance imaging (MRI). As part of a longitudinal study of cognitive aging we have performed MRI on healthy older adults. In a group of 46 volunteers (25 females; median age 73, range 63-84 years), we have calculated of the Hachinski score and Framingham Stroke Risk Profile (FSRP). Volunteers also provided self-reported health information using the Cornell Medical Index (CMI). These were compared against the total Age Related White Matter Changes (ARWMC) score. The mean total ARWMC score was 7.4 + or - 5.27 (+ or - S.D.) and only 3 (6.5%) individuals had no evidence of WMH. Regression analysis of individual variables identified self-report of cardiovascular disease from the CMI, section C as the only significant predictor of ARWMC. A multivariate linear regression model also identified FSRP at 1 year as a second independently significant predictor. The multivariate model accounted for 19% of the variance in total ARWMC score. The only 6.5% of individuals who had no WMH is in keeping with previous studies. The important finding was the positive relationship with self-reported cardiovascular disease, which is a possible biomarker of sub-clinical cerebrovascular disease (CVD).

Type 2 diabetes whole-genome association study in four populations: the DiaGen consortium

Type 2 diabetes (T2D) is a common, polygenic chronic disease with high heritability. The purpose of this whole-genome association study was to discover novel T2D-associated genes. We genotyped 500 familial cases and 497 controls with >300,000 HapMap-derived tagging single-nucleotide-polymorphism (SNP) markers. When a stringent statistical correction for multiple testing was used, the only significant SNP was at TCF7L2, which has already been discovered and confirmed as a T2D-susceptibility gene. For a replication study, we selected 10 SNPs in six chromosomal regions with the strongest association (singly or as part of a haplotype) for retesting in an independent case-control set including 2,573 T2D cases and 2,776 controls. The most significant replicated result was found at the AHI1-LOC441171 gene region.

Perceptions of risk and prevention of dementia in the healthy elderly

OBJECTIVES

(1) To determine the attitudes and perceptions of the elderly with regard to dementia. (2) To correlate these beliefs with demographic variables of age, sex, intelligence scores and social class.

METHOD

A postal questionnaire survey of a sample of 562 subjects of the Manchester University Age and Cognitive Performance longitudinal study group.

RESULTS

The response rate was 95%. Most responders (69%) did not worry about dementia, although they were more likely to think about it if they had a family member with dementia (p < 0.005). There is no link between social class, sex, intelligence scores and age with regard to worries and concerns of dementia. The majority of responders (82%) took action to maintain their health but demonstrated poor awareness of risks or protective factors for dementia.

CONCLUSION

The elderly on the whole were not fearful of dementia or of acquiring it. There was poor awareness of risks or protective factors for dementia.

Apolipoprotein E epsilon4 allele frequency and age at onset of Alzheimer's disease

The age distribution of the epsilon4 allelic form of the apolipoprotein E gene (APOE) was investigated in 630 patients with Alzheimer's disease (AD) with onset age ranging from 35 to 90 years. Overall, mean age at onset in APOE epsilon4 allele bearers was significantly later than that in nonbearers. However, when stratified into early onset AD (EOAD) and late onset (LOAD) groups, mean age at onset in EOAD cases bearing APOE epsilon4 allele was later than that in those EOAD cases without epsilon4 allele, whereas in LOAD mean age at onset in cases bearing APOE epsilon4 allele was earlier than in those without epsilon4 allele. When analysed by decade, it was observed that 37% of the total number of APOE epsilon4 allele bearers, and 43% of total number of cases with APOE epsilon4/epsilon4 genotype fell into the 60-69 years age class. Hence, APOE epsilon4 allele frequency, at 0.44, was highest in the 60-69 years age class, progressively decreasing either side of this age group. APOE epsilon4 allele therefore has its maximum impact between onset ages of between 60 and 70 years.

Genetic associations between cathepsin D exon 2 C-->T polymorphism and Alzheimer's disease, and pathological correlations with genotype

Genetic variations represent major risk factors for Alzheimer's disease (AD). While familial early onset AD is associated with mutations in the amyloid precursor protein and presenilin genes, only the e4 allele of the apolipoprotein E (APOE) gene has so far been established as a genetic risk factor for late onset familial and sporadic AD. It has been suggested that the C-->T (224Ala-->Val) transition within exon 2 of the cathepsin D gene (CTSD) might represent a risk factor for late onset AD. The objective of this study was to investigate whether possession of the CTSD exon 2 T allele increases the risk of developing AD, and to determine whether this modulates the amyloid pathology of the disease in conjunction with, or independent of, the APOE e4 allele. Blood samples were obtained from 412 patients with possible or probable AD and brain tissues from a further 148 patients with AD confirmed by postmortem examination. CTSD and APOE genotyping were performed by PCR on DNA extracted from blood, or from frontal cortex or cerebellum in the postmortem cases. Pathological measures of amyloid beta protein (Abeta), as plaque Abeta40 and Abeta42(3) load and degree of cerebral amyloid angiopathy were made by image analysis or semiquantitative rating, respectively. CTSD genotype frequencies in AD were not significantly different from those in control subjects, nor did these differ between cases of early or late onset AD or between younger and older controls. There was no gene interaction between the CTSD T and APOE e4 alleles. The amount of plaque Abeta40 was greater in patients carrying the CTSD T allele than in non-carriers, and in patients bearing APOE e4 allele compared with non-carriers. Possession of both these alleles acted synergistically to increase levels of plaque Abeta40, especially in those individuals who were homozygous for the APOE e4 allele. Possession of the CTSD T allele had no effect on plaque Abeta42(3) load or degree of CAA. Possession of the CTSD T allele does not increase the risk of developing AD per se, but has a modulating effect on the pathogenesis of the disorder by increasing, in concert with the APOE e4 allele, the amount of Abeta deposited as senile plaques in the brain in the form of Abeta40.

The apolipoprotein E epsilon4 allele selectively increases the risk of frontotemporal lobar degeneration in males

OBJECTIVE

To determine whether polymorphic variations in the apolipoprotein E gene (APOE) are associated with increased risk of frontotemporal lobar degeneration (FTLD) when mutation in tau gene is absent.

METHODS

The APOE gene was genotyped by polymerase chain reaction from DNA routinely extracted from blood or brain tissues. The APOE epsilon4 allele frequency in 198 patients with FTLD not associated with mutations in tau gene was compared with that of a control group of 756 normal individuals drawn from the same geographical region. Analyses were done according to clinical subtype or sex.

RESULTS

The APOE epsilon4 allele frequency (19.4%) was increased (p = 0.01) in FTLD v the whole control group (14.1%), while the APOE epsilon2 allele frequency in FTLD (6.5%) was slightly lower than in controls (8.0%) (NS). The APOE epsilon4 allele frequency in men with FTLD (22.3%) was greater (p = 0.002) than in male controls (12.3%); the frequency in women (16.3%) was similar to that in female controls (14.8%) (NS). The APOE epsilon2 allele frequency in men with FTLD was 4.9% while in male controls it was 9.5% (p = 0.06), but there was no difference in women (7.5% v 7.9%, NS). Neither the APOE epsilon2 nor APOE epsilon4 allele frequency varied significantly between any of the clinical subtypes.

CONCLUSIONS

In FTLD not associated with mutations in tau gene, possession of APOE epsilon4 allele in men roughly doubles the chances of developing disease, whereas this has no impact upon disease risk in women.

Relationship between self-reported prevalence of diabetes mellitus using the Cornell Medical Index (CMI) and prevalence determined by glycosylated hemoglobin (HbA(1c)) in an elderly community-dwelling population

Reports of diabetes mellitus samples in community-dwelling unselected populations suggest a prevalence of 6%. A further 3% of unknown diabetes mellitus subjects are suggested when using formal biochemical methods of diagnosis. In this study, we present the prevalence of diabetes mellitus by self-reports using the CMI and concomitant biochemical detection in 436 community-dwelling older adults who have participated in a 20-year-study of age and cognitive performance in Manchester, UK. Twenty-three of the group reported that they had diagnosed diabetes mellitus, three individuals had a raised HbA(1c) of greater than 7.0% on random testing, but no knowledge of having diabetes mellitus. These individuals were re-contacted and three said they subsequently had a diagnosis of diabetes mellitus made within the two years following the questionnaire. We conclude that in an older population of community-dwelling subjects the numbers of undiagnosed cases of diabetes mellitus is lower than anticipated, based on large unselected population samples. The greater opportunity to interact with health care professionals who may consider screening for diabetes mellitus may explain these findings.

Concordance of Cornell medical index self-reports to structured clinical assessment for the identification of physical health status

Self-reported questionnaires are frequently used to assess health status in epidemiological studies. The Cornell medical index is one such tool used to determine the presence of physical and psychiatric illness but its accuracy and value have been questioned. In this study we have assessed the ability of the CMI to predict health status in two separate patient populations (n = 101, 88) by comparison to a structured medical assessment based on the SENIEUR protocol by two physicians. There was good agreement between medication use reported on the CMI and on medical assessment (k = 0.79; CI: 0.70-0.88). Accuracy of prediction of the CMI for specific medical conditions was good 89-99%. A threshold score from the CMI was not predictive of health as determined by the SENIEUR protocol. In our older populations, we conclude that the CMI accurately predicted health status. The determination of normal health by a threshold score was poorly predictive of heath status. Self-reported medication use was the best predictor of health status.

Estrogen modulates cutaneous wound healing by downregulating macrophage migration inhibitory factor

Characteristic of both chronic wounds and acute wounds that fail to heal are excessive leukocytosis and reduced matrix deposition. Estrogen is a major regulator of wound repair that can reverse age-related impaired wound healing in human and animal models, characterized by a dampened inflammatory response and increased matrix deposited at the wound site. Macrophage migration inhibitory factor (MIF) is a candidate proinflammatory cytokine involved in the hormonal regulation of inflammation. We demonstrate that MIF is upregulated in a distinct spatial and temporal pattern during wound healing and its expression is markedly elevated in wounds of estrogen-deficient mice as compared with intact animals. Wound-healing studies in mice rendered null for the MIF gene have demonstrated that in the absence of MIF, the excessive inflammation and delayed-healing phenotype associated with reduced estrogen is reversed. Moreover, in vitro assays have shown a striking estrogen-mediated decrease in MIF production by activated murine macrophages, a process involving the estrogen receptor. We suggest that estrogen inhibits the local inflammatory response by downregulating MIF, suggesting a specific target for future therapeutic intervention in impaired wound-healing states.

Apolipoprotein E genotype does not predict decline in intelligence in healthy older adults

There is evidence of a genetic influence on the decline in cognitive performance of older adults, although the mechanisms responsible are unknown. A group of 767 subjects of the Manchester University Age and Cognitive Performance longitudinal study volunteer group, followed up from 1985 to the present, were genotyped for apolipoprotein E (APOE). The data from this were related to cross-sectional and longitudinal trends in the Heim intelligence test score (AH4-1) using previously reported random-effects models (Neuropsychologia 39 (2001) 532). There were no significant differences in mean scores for presence compared with absence of the APOE4 or APOE2 genotypes (P=0.48 and P=0.51, respectively). This research does not demonstrate a link between intelligence and APOE genotype in older adults.

Predictors of outcome following hip fracture. Admission time predicts length of stay and in-hospital mortality

Many factors may contribute to the mortality and morbidity following hip fracture, including the provision of care. We wished to examine the contribution of potential factors to in-hospital mortality, length of hospital stay and 90-day mortality by statistical analyses of an audit database of all hip fractures admitted to a teaching hospital following the introduction of a fast track admission system. In-hospital mortality was predicted by ASA grade, the presence of any complications, cardiovascular complications, grade of surgeon, operation type and shorter admission time, a measure of time taken to admit a patient to a hospital bed (P<0.001). Length of hospital stay was predicted by increased age, presence of chronic cognitive impairment/dementia, presence of an implant complication, operation type, fracture type and longer admission time, r=0.455, P<0.001. Ninety-day mortality was predicted by the presence of chronic cognitive impairment/dementia, cardiovascular complications, pulmonary complications, ASA grade, grade of surgeon and admission day, P<0.001. Rapid admission following a hip fracture may not be the ideal management approach for all patient groups. Further study is required to identify factors in the process of care which are associated with better outcomes.

Cortisol kinetics in elderly women with persistently high cortisol concentrations after proximal femur fracture

OBJECTIVES

Elderly women with proximal femur fracture show abnormal persistence of increased cortisol concentrations, which could contribute to the high morbidity associated with this injury. Two weeks after injury, the authors found substantially increased urinary free cortisol excretion, which usually reflects the integrated concentration of free (bioactive) cortisol in plasma. However, there was a proportionally smaller increase in cortisol production rate. The authors have now tested the hypothesis that this was caused by a decreased metabolic clearance rate (MCR) rather than increased renal clearance, because the latter but not the former would invalidate free cortisol excretion as an index.

SETTING

Orthopaedic wards in a teaching hospital.

PATIENTS

Thirteen women aged seventy-one to ninety-two years who had sustained a proximal femur fracture approximately two weeks earlier were compared with ten healthy women aged sixty-seven to eighty-three years. These subjects are similar to those in the authors' previous study.

MAIN OUTCOME MEASUREMENTS

The authors used single injections of [3H] cortisol to measure its MCR and estimated hepatic blood flow with indocyanine green.

RESULTS

The patients with hip fractures had higher plasma cortisol concentrations than did the healthy subjects, as expected. Cortisol MCR was approximately 20 percent lower in the patients, and estimated hepatic blood flow was approximately 35 percent lower in the patients. Analysis of covariance showed that the difference in MCR was the result of the small difference in age between the groups rather than to injury per se.

CONCLUSIONS

A lower cortisol MCR in the patients with hip fractures explains the authors' previous results and validates urinary free cortisol excretion as an index. The data suggest a roughly threefold mean increase in plasma cortisol bioactivity two weeks after hip fracture.

Cardiovascular response to graded lower body negative pressure in young and elderly man

Lower body negative pressure (LBNP) reduces central venous pressure (CVP) and cardiac output. The elderly are reported to have a limited capacity to increase cardiac output by increasing heart rate (HR), are especially dependent on end diastolic volume to maintain stroke volume and therefore should be especially vulnerable to LBNP. The present study compared the effects of LBNP in the young and old. Stroke volume was assessed non-invasively as stroke distance (SD) by aortovelography. Two groups of healthy male volunteers were studied: eight young (29.7 +/- 2.0 years, mean +/- S.E.M.) and nine old (70.1 +/- 0.9 years). LBNP was applied progressively at 17.5, 35 and 50 mmHg in 20 min steps, with measurements taken during each steady state. There were similar, significant, falls in CVP in both groups. SD fell significantly in both groups from respective control values of 24.8 +/- 1.6 and 16.6 +/- 0.9 cm to 12.5 +/- 1.3 and 8.9 +/- 0.4 cm at a LBNP of 50 mmHg. Although SD in the elderly was significantly lower than in the young, the LBNP-induced changes were not different between groups. Both groups produced similar significant increases in vascular resistance, HR, plasma vasopressin (AVP) and noradrenaline. Mean arterial blood pressure (MBP) and plasma adrenaline did not change significantly. Therefore healthy old men respond to LBNP in a similar manner to the young, although MBP and SD are regulated around different baselines in the two groups.

Clinical features of dementia associated with apolipoprotein epsilon4: discrimination with a neural network genetic algorithm

BACKGROUND

It is unclear whether the APOE epsilon4 allele is associated with distinct clinical features in dementia.

METHOD

100 cases meeting ICD criteria for dementia were interviewed using standardized instruments and genotyped for APOE. The presence of the epsilon4 allele was used by a genetic algorithm neural network (GANN) to discriminate symptoms and signs.

RESULTS

The GANN selected six features: gender, systolic blood pressure, absence of ankle tendon reflexes, history of weight loss, history of falls, and interviewer observed lability of mood. Using these features, a neural network discriminated cases according to epsilon4 highly accurately (area under receiver operating characteristic=0.83, sensitivity=0.78, specificity=0.78).

CONCLUSIONS

A GANN is able to discriminate a clinically distinct group of features among dementia patients who express the epsilon4 allele.

Hypocapnia and its relation to fear of falling

OBJECTIVE

To determine if hypocapnia occurs in patients with fear of falling and to explore potential causes of hypocapnia.

DESIGN

Observational study in patients who fall with and without fear of falling.

SETTING

Rehabilitation wards of an elderly care unit.

PATIENTS

Consecutive fallers with (n = 20) and without (n = 10) fear of falling.

MAIN OUTCOME MEASURES

End-tidal CO2 (PETCO2) and respiratory rate (RR) responses were measured during sustained isometric muscle contraction (SIMC) (40% of maximum voluntary contraction of quadriceps for 2 min) and during a 5-meter walk. Falls efficacy scale (FES) and Hospital anxiety and depression scale (HAD).

RESULTS

Patients with fear of falling had significantly higher FES and HAD scores (p < .01). During SIMC, baseline and nadir PETCO2 levels were significantly lower in patients with a fear of falling (p < .01). During the 5-meter walk, PETCO2 was lower at baseline, at nadir, and at the end of the walk in the fear of falling group than in controls (p < .01). RR was higher at nadir and end of the walk in the fear of falling group than in controls (p < .02).

CONCLUSIONS

Hypocapnia may occur in patients with a fear of falling during SIMC and walking. Anxiety seems to be the main cause, but muscle weakness may contribute. Breathing or relaxation techniques and reconditioning may have a role in treating fear of falling in the rehabilitation setting.

Disrupted cortisol-ACTH relationships in elderly women given corticotrophin-releasing hormone two weeks after proximal femur fracture

OBJECTIVE

In elderly women with hip fractures plasma cortisol is persistently higher than in healthy elderly women, possibly causing undesirable catabolic effects. A lack of corresponding changes in plasma ACTH or in the cortisol response to exogenous ACTH has prompted us to study cortisol-ACTH relationships after giving corticotrophin-releasing hormone (CRH) to such subjects.

SUBJECTS

Seventeen women aged 70-90 years who had sustained a hip fracture about two weeks previously were compared with 19 healthy women aged 68-85 years.

MEASUREMENTS

100 microg CRH was injected into each subject and ACTH and cortisol concentrations were measured at intervals for 90 minutes beforehand and 180 minutes afterwards. The concentrations of vasopressin and various cytokines and related peptides were also measured during the baseline period.

RESULTS

Under baseline conditions plasma cortisol was higher and plasma ACTH lower in the injured patients than in the healthy subjects. The patients showed smaller incremental ACTH and cortisol responses to CRF but because of the higher baseline value the peak cortisol concentration was enhanced. A strong correlation between the cortisol and ACTH responses in the healthy subjects was completely lost in the patients and the slope of the ACTH-cortisol dose-response relationship varied greatly between individuals, with no overall increase. The concentrations of vasopressin, interleukin-1 receptor antagonist and soluble tumour necrosis factor receptors were higher in the patients but did not correlate with the responses to CRH.

CONCLUSIONS

The results are not consistent with increased sensitivity to ACTH and suggest an independent stimulus to the adrenals of hip-fracture patients. Its identity is unknown as the non-ACTH stimuli proposed hitherto are reported to enhance sensitivity to ACTH.

New approach to risk determination: development of risk profile for new falls among community-dwelling older people by use of a Genetic Algorithm Neural Network (GANN)

BACKGROUND

Falls risk in older people is multifactorial and complex. There is uncertainty about the importance of specific risk factors. Genetic algorithm neural networks (GANNs) can examine all available data and select the best nonlinear combination of variables for predicting falls. The aim of this work was to develop a risk profile for operationally defined new falls in a random sample of older people by use of a GANN approach.

METHODS

A random sample of 1042 community-dwelling people aged 65 and older, living in Nottingham, England, were interviewed at baseline (1985) and survivors reinterviewed at a 4-year follow-up (n = 690). The at-risk group (n = 435) was defined as those survivors who had not fallen in the year before the baseline interview. A GANN was used to examine all available attributes and, from these, to select the best nonlinear combination of variables that predicted those people who fell 4 years later.

RESULTS

The GANN selected a combination of 16 from a potential 253 variables and correctly predicted 35/114 new fallers (sensitivity = 31%; positive predictive value = 57%) and 295/321 nonfallers (specificity = 92%; negative predictive value = 79%); total correct = 76%. The variables selected by the GANN related to personal health, opportunity, and personal circumstances.

CONCLUSIONS

This study demonstrates the capacity of GANNs to examine all available data and then to identify the best 16 variables for predicting falls. The risk profile complements risk factors in the current literature identified by use of standard and conventional statistical methods. Additional data about environmental factors might enhance the sensitivity of the GANN approach and help identify those older people who are at risk of falling.

A study of infection in elderly nursing/residential home and community-based residents

It is commonly believed that patients admitted to hospital from nursing homes/residential homes (NHRH) with infections are less likely to respond to treatment and have a higher fatality rate than counterparts admitted from their own homes ('the Community'). It is also believed that NHRH's harbour a reservoir of unusual and resistant organisms. These preconceptions may influence how these patients are managed. A database of 10593 sequential admissions to a Geriatric Medical unit over a three-year period was used to identify NHRH and community populations with a principal diagnosis of infection. They were investigated using the Department of Microbiology's database. The admission rate in the NHRH group was twice that of the community group. There were no significant differences in length of stay (LOS) [16 +/- 2 vs 17 +/- 2 days (s.e.m.)], or mean survival time (ST)(61 days (37-84) vs 48 days (25-72): 95% confidence intervals) between the two groups. Subgroups of the NHRH group did have significantly different survival times. Fatality rate was not significantly different between the NHRH (40%) or Community (35%) groups. Both the NHRH and community group underwent very similar levels of investigation (189 vs 200 investigations performed). The types and frequencies of pathogen seen in the two groups were very similar.

Topical estrogen accelerates cutaneous wound healing in aged humans associated with an altered inflammatory response

The effects of intrinsic aging on the cutaneous wound healing process are profound, and the resulting acute and chronic wound morbidity imposes a substantial burden on health services. We have investigated the effects of topical estrogen on cutaneous wound healing in healthy elderly men and women, and related these effects to the inflammatory response and local elastase levels, an enzyme known to be up-regulated in impaired wound healing states. Eighteen health status-defined females (mean age, 74.4 years) and eighteen males (mean age, 70.7 years) were randomized in a double-blind study to either active estrogen patch or identical placebo patch attached for 24 hours to the upper inner arm, through which two 4-mm punch biopsies were made. The wounds were excised at either day 7 or day 80 post-wounding. Compared to placebo, estrogen treatment increased the extent of wound healing in both males and females with a decrease in wound size at day 7, increased collagen levels at both days 7 and 80, and increased day 7 fibronectin levels. In addition, estrogen enhanced the strength of day 80 wounds. Estrogen treatment was associated with a decrease in wound elastase levels secondary to reduced neutrophil numbers, and decreased fibronectin degradation. In vitro studies using isolated human neutrophils indicate that one mechanism underlying the altered inflammatory response involves both a direct inhibition of neutrophil chemotaxis by estrogen and an altered expression of neutrophil adhesion molecules. These data demonstrate that delays in wound healing in the elderly can be significantly diminished by topical estrogen in both male and female subjects.

The effect of aging on skeletal muscle capillarization in a murine model

Capillarization of skeletal muscle has been reported to be both maintained and reduced with advancing age. This conflict may represent methodological differences between biopsy studies. We have examined capillarization throughout two muscles, soleus and extensor digitorum longus (EDL), from a well-established colony of aging mice, and related this to fiber number (C/F ratio) and type. Labeling of muscle capillaries was performed with the biotinylated Griffonia (Bandeiraea) simplicifolia lectin (GSL 1) using immunochemistry. The results showed a significant increase in the C/F ratio in the aged mice when compared with the younger (6-month mice soleus = 1.296, 95% CI 1.226-1.366 vs 28-month mice soleus = 1.530, 95% CI 1.488-1.572, p <.001; 6-month mice EDL = 0.881, 95% CI 0.751-1.011 vs 28-month mice EDL = 1.124, 95% CI 1.028-1.220, p = .017). These differences could not be accounted for by changes in fiber type but may reflect loss of fibers. Alternatively, there may be increased angiogenic drive or a failure of downregulation of angiogenesis.

Serum transferrin receptor assay in iron deficiency anaemia and anaemia of chronic disease in the elderly

The most common cause of anaemia in the elderly is anaemia of chronic disease (ACD). However, iron deficiency anaemia (IDA) may coexist, and can be difficult to diagnose. The serum transferrin receptor (sTfR) blood test may be a better indicator of iron status as it is not affected by inflammation nor by advancing age. We evaluated it in four groups (10 males, 10 females each): 'young' controls, 'elderly' controls, IDA and ACD. All patients in the IDA group had elevated sTfR levels (mean +/- SD 65.2 +/- 17.7 nmol/l). All 'young' controls had normal sTfR (22.3 +/- 7.3 nmol/l) and ferritin levels (92.7 +/- 61.1 micrograms/l). Although all subjects in the 'elderly' controls and ACD group had normal, and raised or normal serum ferritin, respectively (88 +/- 62.3 micrograms/l; 631.2 +/- 509.5 micrograms/l), three (15%) 'elderly' controls and four (20%) ACD patients had raised sTfR levels, suggesting depleted iron stores. Bone-marrow aspirates were available in 3/4 ACD patients with raised sTfR. Haemosiderin was absent in two. The sTfR blood test is comparable to serum ferritin in diagnosing IDA in the elderly but also seems capable of differentiating ACD from IDA. Its potential as a non-invasive test of iron status, especially in elderly anaemic patients, deserves further evaluation.

The effect of aging on the metabolic clearance rate and distribution of cortisol in man

Previous studies of cortisol kinetics in old people have been flawed. All but one used a large dose of unlabelled cortisol, which will itself alter the kinetic parameters, and in none was metabolic clearance rate (MCR) calculated. We have, therefore, injected [(3)H]cortisol into men aged 20-38 and healthy (screened) men and women aged 63-83 years and followed its disappearance from the circulation for 3 h. In all three groups the disappearance curves corresponded closely to a double exponential, with half-lives of around 5 and 65 min. A two-pool model was assumed, one being purely a side-pool. The initial and total volumes of distribution and the MCR, but not the clearance rate for exchange between the two pools, tended to be lower in the elderly men than in the young; only the difference in total volume was significant. All these parameters were lower in the elderly women than in the elderly men. We conclude that any decline in cortisol MCR and related kinetic parameters with aging in men is small compared with variation from other sources. These parameters are lower in elderly women than men, in line with a reported sex difference in MCR in young subjects.

Difficulties in measuring the effect of testosterone replacement therapy on muscle function in older men

Muscle wasting in older men may be related to androgen deficiency. We have assessed the effect of testosterone replacement therapy on muscle function in the upper and lower limbs of older (age > 60 years) men with blood testosterone levels < 14 nmol/L. Subjects (n = 7 per group) received testosterone enanthate 200 mg i.m. or placebo every 2 weeks in a double blind study over a 12-week period and underwent muscle testing every 4 weeks. A significant increase in blood levels of testosterone and a reduction in levels of sex hormone binding globulin occurred in the treatment group. Total body mass, haemoglobin and packed cell volume also increased significantly (p < 0.05). No improvements in handgrip strength, isometric strength of knee flexors and extensors or leg extensor power were seen in either group. Wide variability in all measures of muscle function were observed in these elderly men suggesting that very large study groups would be required to determine potential treatment benefits on muscle function.

Opinions of elderly people on treatment for end-stage renal disease

BACKGROUND

As more people survive into old age, a greater number are becoming eligible for dialysis treatment for end-stage renal failure. In the UK the elderly have previously been excluded from treatment programmes, and continuing financial constraints are unlikely to improve this situation. There are few data on the views of elderly subjects on renal replacement treatment. We have, therefore, explored the views of elderly subjects in this study.

METHODS

50 subjects were selected from hospital geriatric wards and nursing homes. A short clinical vignette about a 75-year-old patient with renal failure was presented, and the subjects were asked to give their opinion on choices made by the patient to different treatment options. The subjects were then asked what choice they would make if in the same situation. They were asked what level of symptoms they would tolerate and for their views on cost and treatment allocation. Important contributors to quality of life were also determined for each subject using visual analogue scales.

RESULTS

84% of the subjects would choose dialysis treatment, and 78% of all elderly would attend hospital as necessary, if their symptoms could be relieved. 54% of the in-patient elderly and 83.3% of nursing home elderly even when physically disabled and living in a nursing home would want dialysis for end-stage renal failure. 74% of all elderly preferred to have home dialysis treatment. Only 36% of the subjects thought cost was important when allocating dialysis to the elderly. Being independent and free from major symptoms was regarded as important for a good quality of life.

CONCLUSIONS

In this survey, elderly subjects wanted dialysis treatment. Neither age nor cost were considered important determinants for resource allocation. Symptom relief and maintaining independence were considered the main goals of treatment.

Injury in the aging: recovery and rehabilitation

Interest in how victims of traumatic injuries recover is increasing and a number of observational studies have now been done. There are very few intervention studies aimed at enhancing recovery, but there will be more as our knowledge base grows. Older recipients of traumatic injuries differ from the young in the types of injuries they sustain, in the way they respond to their injuries and in the consequences of even relatively minor injuries on their future independence. In this paper, we summarise our understanding of recovery after injury and consider this in more depth for older people with specific injuries.

Relationships between different measurements of vascularity and clinico-pathological parameters in breast cancer

Microvascular density has been put forward as an independent prognostic factor in breast cancer, with high levels indicating poorer prognosis. However, various studies have failed to confirm its prognostic value. The reasons for the contradictory results are not known, but it is believed that methodological differences are responsible. To test this hypothesis, we have used four different methods of assessing vascularity (average and highest microvascular density, microvascular volume and image analysis of vascular area) and related them to known prognostic factors in 51 cases of breast cancer NOS. All four methods showed a significant correlation with each other, with the exception of image analysis vs microvascular volume. The average microvascular density was significantly lower in p53 positive compared to negative tumours (median 38.4 and 66.2; IQR 31.1 and 49.4, respectively, p < 0.05). Vascularity, measured by the four methods, was not associated with nodal status or any other parameter examined.

Evolution of artificial neural network architecture: prediction of depression after mania

Artificial neural networks (ANNs) are compared to standard statistical methods for outcome prediction in biomedical problems. A general method for using genetic algorithms to "evolve" ANN architecture (EANN) is presented. Accuracy of logistic regression, a fully interconnected ANN, and an EANN for predicting depression after mania are examined. All methods showed very good agreement (training set accuracy, chi-square all p < 0.01). However, significant differences were found for stability (test set accuracy); logistic regression being the most unstable and EANN being significantly more stable than a fully interconnected ANN (McNemar p < 0.01). We conclude that the EANN method enhances ANN stability. This approach may have particular relevance for biomedical prediction problems, such as predicting depression after mania.