Comax: an expert system for cotton crop management.

Expert systems are computer programs that perform at the level of human experts. One expert system, Comax, has been developed that acts as an expert in cotton crop management. The system has a knowledge base consisting of a sophisticated cotton plant simulation computer program, a set of "if-then" rules, and a computer program called an inference engine. Comax determines the best strategy for irrigating, applying fertilizer, and applying defoliants and cotton boll openers. Sensors in the cotton fields automatically report weather conditions to the system, and Comax reevaluates its recommendations daily. Comax was tested on a large farm and demonstrated excellent results in reducing the unit costs of production.

The -48 C/T polymorphism in the presenilin 1 promoter is associated with an increased risk of developing Alzheimer's disease and an increased Abeta load in brain.

Mutations in the presenilin 1 gene (PS1) account for the majority of early onset, familial, autosomal dominant forms of Alzheimer's disease (AD), whereas its role in other late onset forms of AD remains unclear. A -48 C/T polymorphism in the PS1 promoter has been associated with an increased genetic risk in early onset complex AD and moreover has been shown to influence the expression of the PS1 gene. This raises the possibility that previous conflicting findings from association studies with homozygosity for the PS1 intron 8 polymorphism might be the result of linkage disequilibrium with the -48 CC genotype. Here we provide further evidence of increased risk of AD associated with homozygosity for the -48 CC genotype (odds ratio=1.6). We also report a phenotypic correlation with Abeta(40), Abeta(42(43)), and total Abeta load in AD brains. The -48 CC genotype was associated with 47% greater total Abeta load (p<0.003) compared to CT + TT genotype bearers. These results suggest that the -48 C/T polymorphism in the PS1 promoter may increase the risk of AD, perhaps by altering PS1 gene expression and thereby influencing Abeta load.

Are interleukin-1 gene polymorphisms risk factors or disease modifiers in AD?

Polymorphisms in the interleukin-1 genes, IL-1A and IL-1B, have been associated with AD, but not in all studies. The authors genotyped the IL-1A(-889) and IL-1B(-511) polymorphisms in large independent cohorts of 503 control individuals and 395 patients with AD, and a further 100 with brain Abeta load. No evidence was found of risk for AD with these variants, nor of an effect on age at onset. However, an impact of IL-1B(-511) on Abeta(40) load (p < 0.05) was detected.

Plasma vitamin C, cholesterol and homocysteine are associated with grey matter volume determined by MRI in non-demented old people.

We studied 82 non-demented old people and, using MRI, derived measures of grey and white matter and intracranial volumes. Controlling for sex and intracranial volume, we related grey and white matter volumes to plasma concentrations of vitamins C, B(12), folate, homocysteine, cholesterol, triglycerides, high density and low density (LDL) lipoproteins, and to red blood cell folate and glycated haemoglobin concentrations (HbA1(c)). We found that lower grey matter volume was associated with lower plasma vitamin C and higher homocysteine, cholesterol and LDL. Lower blood cell folate was also associated with lower grey matter volume but HbA1(c) was not. These data are consistent with the putative benefits of dietary vitamin C and folate intake and the role of cholesterol in age related neurodegeneration.

Are the estrogen receptors involved in Alzheimer's disease?

Retrospective analysis shows that women who took estrogen replacement therapy may have less risk of cognitive decline and of developing Alzheimer's disease (AD). The greater risk associated with female gender and these observations suggest that estrogen may be implicated in the aetiology of AD. Estrogen is one of a family of sex steroids that exerts many of its genomic effects through the activation of the nuclear estrogen receptors, ERalpha and ERbeta. Previously, increased risk for AD has been reported for polymorphisms in the ERalpha gene in a Japanese cohort, however, this association has not been systematically replicated. We have further investigated polymorphisms in the ERalpha and have extended this to investigate an association with a polymorphism within the ERbeta gene in an independent UK Caucasian population. We found no independent association of these polymorphisms with the risk of developing AD in the total sample nor within either gender. However, we did detect a significant interaction between the ERalpha and ERbeta polymorphisms and the risk for AD (OR=0.22 95% CI (0.05-0.88), P=0.02). If this finding can be supported in other independent studies, it may suggest that the risk for AD may be modulated only when both ERalpha and ERbeta have particular variations in their expression and/or biological activities.

Mental ability age 11 years and health status age 77 years.

OBJECTIVES: to measure the effects of childhood mental ability on health in old age. DESIGN: longitudinal cohort study. SETTING: community-based. PARTICIPANTS: survivors of the 1932 Scottish Mental Survey cohort randomly selected from the Community Health Index in North East Scotland. MEASUREMENTS: (i) presence of disease by diagnostic category; (ii) cardiovascular, respiratory, anthropomorphic, sensory and locomotor physiological variables; (iii) Barthel index of functional independence; (iv) socio-demographic and socio-economic variables as health status predictors; and (v) score on the Moray House Test in 1932. RESULTS: There was no significant difference in Moray House Test score in 1932 between those with (mean 39.7, S.D. 13.8) and without (mean 40.1, S.D. 12.1) current disease (F = 0.04, P = 0.84). Physiological health status was predicted by demi-span (F = 6.87, P< 0.001), sex (F = 3.69, P = 0.001), deprivation category (F = 1.45, P = 0.05) and the interaction between sex and deprivation category (F = 2.01, P = 0.002). Moray House Test score in 1932 correlated significantly and positively with Barthel score (r = 0.24, P < 0.001). No additional general linear models added any other significant socio-economic variable once Moray House Test Score in 1932 was entered. Moray House Test score in 1932 remained significant (beta = 0.16, P = 0.024) after Mini Mental State Examination score was entered and found to be significant (beta = 0.21, P = 0.003). CONCLUSION: socio-economic and socio-environmental factors are important determinants of some aspects of inequalities in health in old age in this cohort. Pre-morbid mental ability was an important independent predictor of late-life functional independence.

Lack of association between apolipoprotein E genoype and ischaemic stroke in a Scottish population.

BACKGROUND: Apolipoprotein E epsilon4 allele has been associated with increased risk of coronary heart disease, and is also a major genetic susceptibility locus for Alzheimer's disease. Some studies have shown an association between apoE genotype and ischaemic stroke or outcome following stroke, while other studies have failed to do so. Materials and methods Using PCR and the Taqman fluorescence system to detect polymorphisms we examined apoE genotype in 266 ischaemic stroke cases and in a control population. RESULTS: We found no association between apoeE epsilon 4 allele distribution and ischaemic stroke, or with outcome following stroke as measured using the Rankin score. Conclusion This study disagrees with a recent meta-analysis, and suggests that further studies are required to clarify the exact relationship between apoE genotype and ischaemic stroke.

Brain white matter lesions detected by magnetic resonance [correction of resosnance] imaging are associated with balance and gait speed.

OBJECTIVE: To investigate the relations between premorbid and current mental ability, mood, and white matter signal abnormalities detected by T2 weighted brain magnetic resonance imaging (MRI) and impairment of balance and mobility in older adults. METHODS: 97 subjects from the Aberdeen 1921 birth cohort underwent brain MRI, evaluation of balance, and measurement of gait speed. White matter hyperintensities detected on T2 weighted MRI scans were rated by three independent raters on three variables: white matter lesions; periventricular lesions; and brain stem lesions. RESULTS: Decreased gait speed was correlated with impaired visual acuity (p = 0.020), shorter stature (p = 0.008), a lower childhood IQ (p = 0.030), a lower current Raven's progressive matrices score (Raven score) (p < 0.001), a higher hospital anxiety and depression scale (HADS) score (p = 0.004), and an increased grade of brain stem lesions on MRI. Inability to balance was correlated with Raven score (p = 0.042), brain stem lesions (p = 0.003), white matter lesions (p = 0.003), and periventricular lesions (p = 0.038). Binary logistic regression identified brain stem lesions (odds ratio (OR) 0.22; 95% confidence interval 0.09 to 0.54) and HADS depression score (OR 0.75; 0.58 to 0.97) as the only significant associations with balance. Structural equation modelling detected an association between two latent traits representing white matter disease and an integrating function, respectively. CONCLUSIONS: In this cohort, white matter lesions, periventricular lesions, and brain stem lesions were associated with impaired balance. Current mental ability was strongly related to gait speed. There appears to be a concordance between motor skills and intellect in old age, which is degraded by white matter disease.

Pronunciation of irregular words is preserved in dementia, validating premorbid IQ estimation.

The National Adult Reading Test (NART), used to estimate premorbid mental ability, involves pronunciation of irregular words. The authors demonstrate that, after controlling for age 11 IQ test scores, mean NART scores do not differ in people with and without dementia. The correlation between age 11 IQ and NART scores at about age 80 was similar in the groups with (r = 0.63, p < 0.001) and without (r = 0.60, p < 0.001) dementia. These findings validate the NART as an estimator of premorbid ability in mild to moderate dementia.

Dietary supplement use in old age: associations with childhood IQ, current cognition and health.

AIMS: Dietary supplement (DS) use is actively promoted among old people but there is little evidence in favour of DS use or information about the demographic, health and cognitive characteristics of DS users. METHOD: We examined 176 healthy, old people without dementia all born in 1921 and living independently in the community. IQ scores aged about 11 years were available for all subjects. DS users were more often female, had a lower BMI and were taking fewer prescribed medications than non-users. RESULTS: Usual dietary intake, as measured by food frequency questionnaire, did not differ between DS users and DS non-users. DS users were seen to have higher Vitamin C (p<0.05), alpha-carotene (p<0.05) and lower gamma-tocopherol (p<0.001) and homocysteine (p<0.01). DS users did not differ from DS non-users in years of education, indices of occupational code, current socio-economic category or parameters of cardiovascular or respiratory functions. DS users had higher (p<0.05) childhood IQ scores but did not differ in current Mini-Mental State Examination (MMSE) score or performance on Raven's Progressive Matrices (RPM) either before or after adjustment for childhood IQ. CONCLUSIONS: DS users may enjoy somewhat better general health than non-users but the source of this difference is unknown. Possible health benefits of DS use merit further study.

Neuropsychologic correlates of brain white matter lesions depicted on MR images: 1921 Aberdeen Birth Cohort.

PURPOSE: To examine relationships between brain white matter hyperintensities depicted at magnetic resonance (MR) imaging and performance on neuropsychologic tests in community-dwelling elderly adults. MATERIALS AND METHODS: The 1921 Aberdeen Birth Cohort is a subsample of survivors of the Scottish Mental Survey of 1932 whose mental ability was tested at 11 years of age. Ninety-five of these subjects agreed to undergo brain MR imaging, an examination of general health, and a neuropsychologic evaluation. White matter hyperintensities detected at T2-weighted MR imaging were rated by using a semiquantitative method yielding two continuous variables: white matter lesions and periventricular lesions. Cognitive ability, including crystallized and fluid intelligence domains, was assessed with standard neuropsychologic tests. RESULTS: Rating scores of white matter lesions were normally distributed (on a devised scale) with means of 1.14 for white matter lesions and 1.28 for periventricular lesions. Intra- and interobserver reliability coefficients for scores were high, generally above 0.7. There were significant correlations of medium effect size between the T2-weighted MR imaging-depicted white matter lesions and performance on tests of fluid-type intelligence. No significant correlation was demonstrated between white matter lesion ratings and tests of crystallized intelligence. CONCLUSION: Lower fluid-type ("prevailing") intelligence test scores were associated with increased severity of white matter lesion ratings but not crystallized-type ("premorbid") intelligence test scores. This indicates that MR imaging-depicted white matter lesions are of clinical importance.