Amyloid precursor protein (APP) processing genes and cerebrospinal fluid APP cleavage product levels in Alzheimer's disease

The aim of this exploratory investigation was to determine if genetic variation within amyloid precursor protein (APP) or its processing enzymes correlates with APP cleavage product levels: APPα, APPβ or Aβ42, in cerebrospinal fluid (CSF) of cognitively normal subjects or Alzheimer's disease (AD) patients. Cognitively normal control subjects (n = 170) and AD patients (n = 92) were genotyped for 19 putative regulatory tagging SNPs within 9 genes (APP, ADAM10, BACE1, BACE2, PSEN1, PSEN2, PEN2, NCSTN and APH1B) involved in the APP processing pathway. SNP genotypes were tested for their association with CSF APPα, APPβ, and Aβ42, AD risk and age-at-onset while taking into account age, gender, race and APOE ε4. After adjusting for multiple comparisons, a significant association was found between ADAM10 SNP rs514049 and APPα levels. In controls, the rs514049 CC genotype had higher APPα levels than the CA, AA collapsed genotype, whereas the opposite effect was seen in AD patients. These results suggest that genetic variation within ADAM10, an APP processing gene, influences CSF APPα levels in an AD specific manner.

Correlates of constipation in people with Parkinson's

PURPOSE

To investigate clinical, demographic and dietary factors associated with constipation in a sample of community dwelling people with Parkinson's disease, recruited through a specialist outpatient clinic. Partners/carers provided a convenience control group.

SCOPE

Participants completed a baseline questionnaire (background information, diet and exercise, activities of daily living: mobility and manual dexterity, health-related quality of life (SF-12), stool frequency and characteristics, extent of concern due to constipation, laxative taking), and a four-week stool diary. The Rome criterion was used to determine constipation status. Multiple regression methods were used to explore the correlates of constipation. Baseline data were provided by 121 people with Parkinson's, (54 controls), of whom 73% (25%) met the Rome criterion. Prospective diary data from 106 people with Parkinson's (43 controls) showed lower proportions: 35% (7%) meeting the Rome criterion. Among all study subjects, i.e. Parkinson's patients and controls taken together, the presence of constipation is predicted by having Parkinson's disease (p = .003; odds ratio 4.80, 95% CI 1.64-14.04) and mobility score (p = .04; odds ratio 1.15, 95% CI 1.01-1.31), but not by dietary factors. Amongst people with Parkinson's constipation is predicted by number of medications (p = .027). Laxative taking masks constipation, and is significantly associated with wearing protection against bowel incontinence (p = .009; odds ratio 4.80, 95% CI: 1.48-15.52).

CONCLUSIONS

Constipation is disease-related, not a lifestyle factor. More research is needed on optimal management and laxative use.

Assessing the privacy risks of data sharing in genomics

The protection of identity of participants in medical research has traditionally been guaranteed by the maintenance of the confidentiality of health information through mechanisms such as only releasing data in an aggregated form or after identifying variables have been removed. This protection of privacy is regarded as a fundamental principle of research ethics, through which the support of research participants and the public is maintained. Whilst this traditional model was adopted for genetics and genomics research, and was generally considered broadly fit for purpose, we argue that this approach is increasingly untenable in genomics. Privacy risk assessments need to have regard to the whole data environment, not merely the quality of the dataset to be released in isolation. As sources of data proliferate, issues of privacy protection are increasingly problematic in relation to the release of genomic data. However, we conclude that, by paying careful attention to potential pitfalls, scientific funders and researchers can take an important part in attempts to safeguard the public and ensure the continuation of potentially important scientific research.

Factors associated with resistance to dementia despite high Alzheimer disease pathology

BACKGROUND

Autopsy series have shown that some elderly people remain with normal cognitive function during life despite having high burdens of pathologic lesions associated with Alzheimer disease (AD) at death. Understanding why these individuals show no cognitive decline, despite high AD pathologic burdens, may be key to discovery of neuroprotective mechanisms.

METHODS

A total of 36 subjects who on autopsy had Braak stage V or VI and moderate or frequent neuritic plaque scores based on Consortium to Establish a Registry for Alzheimer's Disease (CERAD) standards were included. Twelve had normal cognitive function and 24 a diagnosis of AD before death. Demographic characteristics, clinical and pathologic data, as well as antemortem brain volumes were compared between the groups.

RESULTS

In multiple regression analysis, antemortem hippocampal and total brain volumes were significantly larger in the group with normal cognitive function after adjusting for gender, age at MRI, time from MRI to death, Braak stage, CERAD neuritic plaque score, and overall presence of vascular disease.

CONCLUSION

Larger brain and hippocampal volumes were associated with preserved cognitive function during life despite a high burden of Alzheimer disease (AD) pathologic lesions at death. A better understanding of processes that lead to preservation of brain volume may provide important clues for the discovery of mechanisms that protect the elderly from AD.

Impact of white matter hyperintensity volume progression on rate of cognitive and motor decline

BACKGROUND

White matter hyperintensity (WMH) change on brain MRI is observed with increased frequency in the elderly and has been independently associated with neurologic decline. The degree to which the location and rate of volume increase in WMH affects other structural brain changes along with cognitive and motor performance over time may determine subsequent degrees of risk for dementia and other syndromes of aging.

METHODS

One hundred four cognitively intact men and women followed longitudinally for up to 13 years underwent at least three MRIs with corresponding annual cognitive and neurologic assessments. Brain volume, ventricular CSF (vCSF), and total periventricular (PV) and subcortical WMH volumes were measured. Progression of MRI volumes was examined in relation to rates of cognitive, motor, and cerebral volume change based on slopes of outcomes.

RESULTS

Higher initial total and PV WMH volume was associated with total WMH, PV WMH, and vCSF progression, and with increased time and number of steps to walk 30 feet. Progression of PV WMH volume was associated with increased time to walk 30 feet. Progression of subcortical WMH volume was associated with decreased performance on logical memory testing and increased rate of vCSF volume change.

CONCLUSION

Increased total and periventricular (PV) white matter hyperintensity (WMH) burden and progression of PV WMH burden are associated with decreased gait performance over time, while progression of subcortical WMH volume is associated with memory decline in cognitively intact elderly. Greater progression of WMH burden is associated with an increased risk of memory and gait dysfunction, and thus should not be considered a benign process.

Incidence of risk factors for myocardial infarction and other vascular diseases in patients with psoriasis

BACKGROUND

Recent cross-sectional studies reported a higher prevalence of diabetes and other risk factors for cardiovascular disease in patients with psoriasis than in the general population.

OBJECTIVES

To estimate the cumulative incidences of risk factors for myocardial infarction and other vascular diseases after a first recorded diagnosis of psoriasis and the hazard ratio (HR) for these conditions in patients with psoriasis compared with the general population.

METHODS

We used the General Practice Research Database to conduct a cohort study of 44,164 patients with a first-time diagnosis of psoriasis and 219,784 nonpsoriasis comparison subjects psoriasis-matched on age, sex and index date.

RESULTS

HRs were increased among patients with psoriasis vs. the comparison cohort for incident diabetes [HR 1.33; 95% confidence interval (CI) 1.25-1.42], hypertension (HR 1.09; 95% CI 1.05-1.14), obesity (HR 1.18; 95% CI 1.14-1.23) and hyperlipidaemia (HR 1.17; 95% CI 1.11-1.23). Patients with psoriasis also had higher risks of incident myocardial infarction (HR 1.21; 95% CI 1.10-1.32), angina (HR 1.20; 95% CI 1.12-1.29), atherosclerosis (HR 1.28; 95% CI 1.10-1.48), peripheral vascular disease (HR 1.29; 95% CI 1.13-1.47) and stroke (HR 1.12; 95% CI 1.00-1.25).

CONCLUSIONS

Risk factors for cardiovascular disease as well as myocardial infarction and other vascular diseases occur with higher incidence in patients with psoriasis than in the general population. Further work is needed to investigate whether these associations involve causal factors related to psoriasis or its treatment.

Deoxyribonucleoside toxicity in adenosine deaminase and purine nucleoside phosphorylase deficiency: implications for the development of new immunosuppressive agents

The immunodeficient state associated with adenosine deaminase (ADA) and purine nucleoside phosphorylase (PNP) deficiency may result from the selective phosphorylation by thymus-derived lymphocytes of the ADA substrate deoxyadenosine and the PNP substrate deoxyguanosine, leading to the intracellular trapping of toxic deoxyribonucleoside triphosphates. Agents such as deoxycytidine might be able to favourably modify the immunodeficient state by inhibiting deoxyribonucleoside phosphorylation. Deficiencies of other nucleotide catabolic enzymes, if selectively expressed by lymphocytes, might also lead to immunodeficiency via nucleoside trapping in lymphoid tissues. Purine deoxyribonucleoside analogues, either alone or in combination with ADA inhibitors, may have value as lymphospecific antimetabolites.

An aberrant protein complex in CSF as a biomarker of Alzheimer disease

OBJECTIVE

To determine if an aberrant protein complex consisting of prostaglandin-d-synthase (PDS) and transthyretin (TTR) in CSF differentiates between subjects with Alzheimer disease (AD) and normal control (NC) subjects.

METHODS

Western blot analysis and a unique sandwich ELISA were used to quantify levels of complexed PDS/TTR in ventricular CSF of subjects with autopsy-verified diagnoses and in lumbar CSF of living subjects with mild to moderate probable AD and age-matched NC subjects. Ventricular CSF was obtained from short postmortem interval autopsies of 7 NC subjects (4 men/3 women), 12 diseased control (DC) subjects (7 men/5 women), 4 subjects with mild cognitive impairment (MCI) (2 men/2 women), and 8 subjects with late-stage AD (LAD) (4 men/4 women). Lumbar CSF was obtained from 15 subjects with probable AD (5 men/10 women) and 14 age-matched NC subjects (10 men/4 women) and was analyzed in a double-blind fashion.

RESULTS

A significant increase in complexed PDS/TTR in ventricular CSF was found in MCI and LAD subjects but not DC subjects compared with NC subjects. Double-blind analysis of complexed PDS/TTR in lumbar CSF showed a significant sixfold increase in levels of the PDS/TTR complex in living probable AD subjects compared with age-matched NC subjects and a 100% sensitivity and 93% specificity in the identification of subjects with AD.

CONCLUSION

After further study of larger numbers of patients, quantifying prostaglandin-d-synthase/transthyretin complex in CSF may be useful in the diagnosis of Alzheimer disease, possibly in the early stages of the disease.

A randomized placebo-controlled trial of Ginkgo biloba for the prevention of cognitive decline

OBJECTIVE

To assess the feasibility, safety, and efficacy of Ginkgo biloba extract (GBE) on delaying the progression to cognitive impairment in normal elderly aged 85 and older.

METHODS

Randomized, placebo-controlled, double-blind, 42-month pilot study with 118 cognitively intact subjects randomized to standardized GBE or placebo. Kaplan-Meier estimation, Cox proportional hazard, and random-effects models were used to compare the risk of progression from Clinical Dementia Rating (CDR) = 0 to CDR = 0.5 and decline in episodic memory function between GBE and placebo groups.

RESULTS

In the intention-to-treat analysis, there was no reduced risk of progression to CDR = 0.5 (log-rank test, p = 0.06) among the GBE group. There was no less of a decline in memory function among the GBE group (p = 0.05). In the secondary analysis, where we controlled the medication adherence level, the GBE group had a lower risk of progression from CDR = 0 to CDR = 0.5 (HR = 0.33, p = 0.02), and a smaller decline in memory scores (p = 0.04). There were more ischemic strokes and TIAs in the GBE group (p = 0.01).

CONCLUSIONS

In unadjusted analyses, Ginkgo biloba extract (GBE) neither altered the risk of progression from normal to Clinical Dementia Rating (CDR) = 0.5, nor protected against a decline in memory function. Secondary analysis taking into account medication adherence showed a protective effect of GBE on the progression to CDR = 0.5 and memory decline. Results of larger prevention trials taking into account medication adherence may clarify the effectiveness of GBE. More stroke and TIA cases observed among the GBE group requires further study to confirm.

Combined coinhibitory and costimulatory modulation with anti-BTLA and CTLA4Ig facilitates tolerance in murine islet allografts

Complex interactions between positive and negative cosignaling receptors ultimately determine the fate of the immune response. The recently identified coinhibitory receptor, B and T lymphocyte attenuator (BTLA), contributes to regulation of autoimmune and potentially alloimmune responses. We investigated the role of BTLA in a fully major histocompatibility complex-mismatched mouse islet transplant model. We report that anti-BTLA mAb (6F7) alone does not accelerate graft rejection. Rather, while CTLA4Ig alone improved allograft survival, the addition of anti-BTLA mAb to CTLA4Ig led to indefinite (>100 days) allograft survival. Immediately after treatment with anti-BTLA mAb and CTLA4Ig, islet allografts showed intact islets and insulin production despite a host cellular response, with local accumulation of Foxp3+ cells. We clearly demonstrate that combined therapy with anti-BTLA mAb and CTLA4Ig mice induced donor-specific tolerance, since mice accepted a second donor-specific islet graft without further treatment and rejected third party grafts. CTLA4Ig and anti-BTLA mAb limited the initial in vivo proliferation of CFSE-labeled allogeneic lymphocytes, and anti-BTLA mAb enhanced the proportion of PD-1 expressing T cells while depleting pathogenic BTLA+ lymphocytes. We conclude that targeting the BTLA pathway in conjunction with CTLA4Ig costimulatory blockade may be a useful strategy for promoting immunological tolerance in murine islet allografts.

Trajectories of brain loss in aging and the development of cognitive impairment

BACKGROUND

The use of volumetric MRI as a biomarker for assessing transitions to dementia presumes that more rapid brain loss marks the clinical transition from benign aging to mild cognitive impairment (MCI). The trajectory of this volume loss relative to the timing of the clinical transition to dementia has not been established.

METHODS

The authors annually evaluated 79 healthy elderly subjects for up to 15 consecutive years with standardized clinical examinations and volumetric brain MRI assessments of ventricular volume. During the study period, 37 subjects developed MCI. A mixed effects model with a change point modeled the pattern of brain volume loss in healthy aging compared with subjects diagnosed with MCI.

RESULTS

The brain loss trajectory of subjects developing MCI during follow-up differed from healthy aging in a two-phase process. First, the annual rate of expansion of ventricular volume decreased with age; however, the annual rates of expansion were greater in those who developed cognitive impairment during follow-up compared with those who did not. Further, subjects who developed MCI had an acceleration of ventricular volume expansion approximately 2.3 years prior to clinical diagnosis of MCI.

CONCLUSIONS

Ventricular expansion is faster in those developing mild cognitive impairment years prior to clinical symptoms, and eventually a more rapid expansion occurs approximately 24 months prior to the emergence of clinical symptoms. These differential rates of preclinical atrophy suggest that there are specific windows for optimal timing of introduction of dementia prevention therapies in the future.

CSF tau/Abeta42 ratio for increased risk of mild cognitive impairment: a follow-up study

BACKGROUND

Processes of Alzheimer disease (AD) likely begin years prior to the onset of cognitive impairment (latent AD), progress though a prodromal phase of mild cognitive impairment (MCI), and culminate in dementia. While many studies have evaluated CSF tau and Abeta(42) as biomarkers of the dementia or prodromal stages of AD, we are unaware of any study to evaluate these potential CSF biomarkers of latent AD.

METHODS

We determined the ratio of CSF tau/Abeta(42) (T/Abeta) using Luminex reagents in 129 control individuals that spanned from 21 to 100 years of age; for comparison we included patients with MCI (n = 12), probable AD (n = 21), or other neurodegenerative diseases (n = 12).

RESULTS

We identified 16% of the control group with abnormally elevated CSF T/Abeta; all were 53 years or older. Using age-matched controls with normal CSF T/Abeta we showed that the high CSF T/Abeta subgroup of controls had significantly increased frequency of the epsilon4 allele of the apolipoprotein E gene and significantly increased risk of conversion to MCI during follow-up of up to 42 months suggesting that they had latent AD at the time of lumbar puncture.

CONCLUSIONS

These generally applicable methods establish cutoff values to identify control individuals at increased risk of conversion to mild cognitive impairment which may be useful to people weighing the risk-benefit ratio of new preventive therapeutics and to researchers striving to enrich clinical trial populations with people with latent Alzheimer disease.

Brain volumes in Guam dementia vs Parkinson dementia complex vs aging Chamorro adults

We sought to determine if Chamorro individuals with a family history of Guam dementia (GD) or Parkinson dementia complex (PDC) exhibit presymptomatic brain MRI changes. Sixty-six Chamorro subjects had neurocognitive assessment and volumetric MRI. MRI brain volumes differed between diagnostic groups (GD, PDC, control) and according to family history. Chamorros with a family history of PDC or dementia may have increased brain atrophy, suggesting a hereditary susceptibility to neurodegenerative disorders.

Blood-brain barrier impairment in Alzheimer disease: stability and functional significance

OBJECTIVE

To determine the stability and functional significance of blood-brain barrier (BBB) integrity in patients with mild to moderate Alzheimer disease (AD).

METHODS

Thirty-six patients (mean age 71 +/- 7 years) with mild to moderate AD (Mini-Mental State Examination [MMSE] 19 +/- 5) participated in a biomarker study involving clinical assessments, brain imaging, and CSF and plasma collection over 1 year. BBB integrity was assessed with the CSF-albumin index (CSF-AI).

RESULTS

BBB disruption was present in an important subgroup of patients (n = 8/36, 22%) at all time points measured. CSF-AI was highly reproducible over 1 year with an intraclass correlation of 0.96. Age, sex, and APOE status did not correlate with CSF-AI. Vascular factors (blood pressure, Hachinski ischemia score, MR-derived white matter hyperintensity, body mass index) were not strongly associated with CSF-AI levels (p = 0.066). CSF/plasma IgG ratio correlated with CSF-AI in a manner indicating that peripheral IgG has greater access to the CNS in patients with an impaired BBB. Further evidence for the physiologic significance of the CSF-AI was noted in the form of correlations with rates of disease progression, including annual change on MMSE (r(2) = 0.11, p = 0.023), annual Clinical Dementia Rating sum-of-boxes change (r(2) = 0.29, p = 0.001), and annual ventricular volume change (r(2) = 0.17, p = 0.007).

CONCLUSIONS

Blood-brain barrier (BBB) impairment is a stable characteristic over 1 year and present in an important subgroup of patients with Alzheimer disease. Age, gender, APOE status, vascular risk factors, and baseline Mini-Mental State Examination score did not explain the variability in BBB integrity. A role for BBB impairment as a modifier of disease progression is suggested by correlations between CSF-albumin index and measures of disease progression over 1 year.

An unobtrusive in-home monitoring system for detection of key motor changes preceding cognitive decline

The existing paradigm of ongoing or posttreatment monitoring of patients through periodic but infrequent office visits has many limitations. Relying on self-report by the patient or their family is equally unreliable. We propose an alternative paradigm in which continuous, unobtrusive monitoring is used to observe changes in physical behavior over time. We highlight the use of this technique for monitoring motor activity that may be predictive of early cognitive changes in the elderly. Initial results using a system of low-cost wireless sensors are presented, together with a discussion of appropriate analyses and interpretation of such data. Using low-cost wireless sensor network coupled with algorithms to detect changes in relevant patterns of behavior, we are able to detect both acute and gradual changes that may indicate a need for medical intervention.

Cycad exposure and risk of dementia, MCI, and PDC in the Chamorro population of Guam

OBJECTIVE

To study cycad-derived products as possible risk factors for dementia, mild cognitive impairment (MCI), and parkinsonism-dementia complex (PDC) on Guam.

METHODS

Complete risk factor data from in-person interviews of 166 cases of Guam dementia, 50 cases of amnestic MCI, and 21 cases of PDC were compared with 1,581 controls in the base population regarding exposure to cycad-derived products from a traditional food (fadang), consumption of fruit bats, and use of cycad-derived topical medicine.

RESULTS

Adjusted odds ratios (ORs) and 95% CIs for picking, processing, and eating fadang in young adulthood ranged from 1.42 (1.05 to 1.91) to 2.87 (1.48 to 5.56) and were consistently elevated and significant across all three diagnostic outcomes. Associations independent of exposure in young adulthood were for picking (OR 0.78, 95% CI 0.64 to 0.96) and processing (OR 0.77, 95% CI 0.63 to 0.94) fadang in childhood with Guam dementia. Men showed stronger and more consistent relations across exposure groups in young adulthood compared with women. No associations were found for consumption of fruit bats or exposure to cycad used as a topical medicine for any of the outcomes. Estimated adjusted population attributable risks suggest that exposure to eating fadang in young adulthood incurred the highest attributable risk percent.

CONCLUSIONS

Environmental lifestyle and diet may contribute to the etiology of neurodegenerative diseases in the native population of Guam.

Prevalence of dementia in Chamorros on Guam: Relationship to age, gender, education, and APOE

OBJECTIVES

To estimate the prevalence of dementia and its clinical subtypes among Chamorros on Guam aged 65 years or older and to examine associations with age, gender, education, and APOE genotype.

BACKGROUND

Chamorros, the indigenous people of Guam, had a high incidence of ALS and parkinsonism-dementia complex (PDC), in the 1950s. Over the next 50 years, ALS incidence declined markedly, but PDC only slightly. The prevalence of late life dementia in Chamorros and its relationship to ALS/PDC are unknown.

METHODS

Island-wide population-based survey of Chamorros aged 65 years or older as of January 1, 2003. Two-stage assessment: cognitive and motor screening, followed by neurologic and psychometric evaluation. Data were reviewed at consensus conference to make clinical diagnoses.

RESULTS

Of 2,789 Chamorros aged 65 years or older, 73% were enrolled; 27% declined participation, died before contact or screening, or moved off Guam. The point prevalence of all-cause dementia on February 1, 2004, was 12.2%. Prevalence data for subtypes were as follows: Guam dementia (clinically equivalent to AD), 8.8%; PDC, 1.5%; pure vascular dementia, 1.3%; other, 0.6%. The prevalence of dementia rose exponentially with age. Low education was significantly associated with dementia, but gender was not. There was a trend toward higher PDC prevalence among men. The APOE epsilon4 allele was not associated with dementia.

CONCLUSIONS

The prevalence of dementia among elderly Chamorros is relatively high. Guam dementia is the most common diagnosis and exceeds parkinsonism-dementia complex. Age and low education are strongly associated with dementia, but gender and APOE epsilon4 are not. Incidence studies will allow risk factors for dementia to be clarified.

Genetic testing without consent: the implications of the new Human Tissue Act 2004

Despite its focus on consent the new Human Tissue Act 2004 allows for testing without consent where a relative could benefit

A semantically enabled formalism for the knowledge management of Parkinson's disease

Bio-ontology is a formal representation of biological concepts that is used in the interchange of communication between computers and humans alike. They can then be used in the formulation and retrieval of knowledge. In developing a knowledge-based system for Parkinson's Disease, a procedure of knowledge map was used to capture and harness the intellectual resources of an organization, and new paradigms for knowledge mapping were also formulated. Knowledge bases for symptoms and drugs, physiotherapy, speech and language therapy, and dieting that affect patient care were developed. Finally, the knowledge bases were merged to form a single central repository of knowledge base.

Cortical excitability and age-related volumetric MRI changes

OBJECTIVE

Normative data on transcranial magnetic stimulation (TMS)-derived measures of cortical excitability in the elderly is sparse. Nevertheless, elderly subjects are included as controls in studies utilizing TMS to investigate disease states. Age-associated increased ventricular cerebrospinal fluid CSF (vCSF) and white matter hyperintensity (WMH) MRI volumes have uncertain significance in non-demented elderly. Information regarding cortical excitability in neurologically intact elderly would augment our understanding of the pathophysiology of aging and assist in the interpretation of TMS studies involving elderly subjects.

METHODS

Twenty-four healthy elderly subjects underwent TMS testing to determine outcomes of resting motor threshold (RMT) cortical silent period (cSP) and central motor conduction time for examination in relation to WMH, vCSF, and CNS volumes.

RESULTS

Increased vCSF and WMH volumes were associated with decreased right and left hemisphere RMT. Smaller CNS volumes were associated with decreased right hemisphere RMT and shorted cSP.

CONCLUSIONS

Commonly observed age-associated MRI changes are associated with findings consistent with increased cortical excitability.

SIGNIFICANCE

Age-related MRI findings likely reflect changes at a cellular level, and may influence cognitive and motor integrity in the elderly. Future TMS studies investigating cortical excitability may wish to consider neuroimaging markers of neurodegeneration prior to enrolling elderly subjects as controls.

Effects of a gamma-secretase inhibitor in a randomized study of patients with Alzheimer disease

LY450139 dihydrate, a gamma-secretase inhibitor, was studied in a randomized, controlled trial of 70 patients with Alzheimer disease. Subjects were given 30 mg for 1 week followed by 40 mg for 5 weeks. Treatment was well tolerated. Abeta(1-40) in plasma decreased by 38.2%; in CSF, Abeta(1-40) decreased by 4.42 +/- 9.55% (p = not significant). Higher drug doses may result in additional decreases in plasma Abeta concentrations and a measurable decrease in CSF Abeta.

Brain volume loss in MCI predicts dementia

Rates of temporal horn volume change were significantly greater in the subjects with mild cognitive impairment who were developing dementia vs those who remained stable.

Asynchronous regional brain volume losses in presymptomatic to moderate AD

To determine if rates and locations of brain volume loss associated with AD are phase-specific, occurring prior to clinical onset and at later stages, we performed longitudinal volumetric MRI analysis on 155 subjects enrolled in a prospective study of aging and dementia. Subjects were divided by Clinical Dementia Rating (CDR) scale into stages of Normal (CDR 0 --> 0), Very Mild (CDR 0 --> 0.5 and 0.5 --> 0.5), Mild (CDR 0.5 --> 1.0 and 1.0 --> 1.0) and Moderate (CDR 1.0 --> 2.0 and 2.0 --> 2.0) dementia. Rates of volume change in CSF spaces, lobar and medial temporal lobe regions were analyzed for group differences across stages. Annual rates of ventricular volume change differed between non-demented and very mild group (p<0.01). In later severity stages, ventricular, temporal, basal ganglia-thalamic region and total volumes show change. Rates of volume loss increase as dementia progresses, but not uniformly in all regions. These regional and phase-specific volume changes form targets for monitoring disease-modifying therapies at clinically relevant, defined stages of dementia.

Symptomatic hypocalcaemia and renal impairment associated with bisphosphonate treatment in patients with multiple myeloma

We report three cases of severe hypocalcaemia associated with i.v. bisphosphonate treatment in patients with multiple myeloma. All patients had symptomatic hypocalcaemia, including a tonic-clonic seizure and tachyarrhythmia in one case. Two cases were associated with the development of acute renal failure, whereas the third patient had pre-existing renal impairment. We recommend that bisphosphonates be used with caution in patients with myeloma and renal impairment, that vitamin D deficiency be corrected prior to treatment (to reduce the risk of hypocalcaemia) and that serum calcium and renal function be monitored during treatment.

Epidemiology of lower limb fractures in general practice in the United Kingdom

STUDY OBJECTIVE

To estimate the incidence of lower limb fractures in the United Kingdom and assess the relative importance of various risk factors for lower limb fractures.

DESIGN

Cohort analysis and matched case-control study.

SETTING

General practices contributing information to the General Practice Research Database.

SUBJECTS

Individuals registered with these general practices who were at risk for a first time lower limb fracture from 1 January 1990 to 31 December 2001.

MAIN OUTCOME MEASURES

Age, sex, and fracture site specific incidence rates; relative risks and population attributable risks for various medical risk factors.

RESULTS

Overall, the risk of lower limb fracture was 17% higher in women then in men. Within age groups, men and women had generally similar proportions of fractures at specific sites in the lower limb. Among the risk factors evaluated, road collisions were associated with the highest relative risk for lower limb fracture, but only accounted for 3.1% or less of the population attributable risk for specific fracture types in any age group. The relative risk for lower limb fracture associated with a diagnosis of dementia was 2.3 (95% confidence interval 2.0 to 2.6), while relative risk estimates for other medical diagnoses were less than 2. Fracture risk was increased among current users of corticosteroids, antipsychotics, antidepressants, and hypnotic/sedatives, but the population attributable risks for each of these drug classes within fracture and age specific strata were only 3.0% or less.

CONCLUSIONS

Many risk factors for lower limb fracture have been identified, but population attributable risk estimates for various risk factors are small. These findings suggest that multifactorial prevention programs are needed to decrease the incidence of lower limb fractures in the general population.

Predicting the rate of cognitive decline in aging and early Alzheimer disease

OBJECTIVES

To determine prognostic factors affecting the course of Alzheimer disease (AD) and to determine the role of region-specific brain volumes as predictors of cognitive decline.

METHODS

Longitudinal data from 166 normal elderly individuals and 59 early AD patients were analyzed. Brain volumes were extracted from MRI scans using semiautomated recursive segmentation methods. Prognostic factors were considered significant if they had a significant effect on the rate of cognitive decline.

RESULTS

In multivariate analysis, higher Clinical Dementia Rating Scale (CDR) score at entry was a significant prognostic factor for an increased rate of cognitive decline. Significant prognostic factors within the baseline CDR = 0 group were base rate of progression and percent total high signal intensity (HSI), percent ventricular, and percent CSF volumes. Base rate of progression, family history, and percent ventricular volume were significant prognostic factors within the CDR = 0.5 group and APOE had a marginally significant effect on the rate of cognitive decline in the CDR = 1 group.

CONCLUSIONS

Percent total HSI, ventricular, and total CSF volume measures can independently predict the rate of cognitive decline and improve the predictive power of statistical models that use only clinical data. Brain volumetric measures from MRI can be used to estimate the rate of cognitive decline even among normal elderly individuals and thus may aid in the prediction of time of onset of disease.

Statin use and cancer risk in the General Practice Research Database

In a matched case–control study using the General Practice Research Database, current statin use was not associated with a significantly altered risk of any of 13 studied cancers. Untreated hyperlipidaemia was associated with slightly increased risks of colon cancer (relative risk 1.8; 95% confidence interval 1.2–2.8), prostate cancer (1.5; 1.1–2.0), and bladder cancer (1.9; 1.2–3.1).

Acute carbon dioxide exposure in healthy adults: evaluation of a novel means of investigating the stress response

Acute hypercapnia was studied to assess its potential as a noninvasive and simple test for evoking neuroendocrine, cardiovascular and psychological responses to stress in man. A single breath of four concentrations of carbon dioxide (CO(2)), 5%, 25%, 35% and 50%, was administered to nine healthy volunteers in a randomized, single-blind fashion. Although no adverse effects occurred, most subjects were unable to take a full inspired vital capacity breath of 50% CO(2). In response to the remaining exposures, subjective and somatic symptoms of anxiety increased in a dose-dependent manner. Unlike 5% and 25% CO(2), 35% CO(2) stimulated significant adrenocorticotropic hormone and noradrenaline release at 2 min and cortisol and prolactin release at 15 min following inhalation. This same dose also provoked a significant bradycardia that was followed by an acute pressor response. No significant habituation of psychological, hypothalamic-pituitary-adrenal (HPA) or cardiovascular responses following 35% CO(2) was seen when this dose was repeated after 1 week. A single breath of 35% CO(2) safely and reliably produced sympathetic and HPA axis activation and should prove a useful addition to currently available laboratory tests of the human stress response.

Changes in premorbid brain volume predict Alzheimer's disease pathology

OBJECTIVE

To assess whether changes in antemortem MRI brain volume measurements are valid predictors of subsequent Alzheimer disease (AD) pathology.

METHODS

Thirty-nine subjects, 15 nondemented and 24 with cognitive impairment, were followed until death. Regional postmortem measures of senile plaque (SP) and neurofibrillary tangle (NFT) severity were examined in relationship to cross-sectional and longitudinal volumetric measurements obtained from antemortem MRI.

RESULTS

Total brain volume change over time was related to the accumulation of cortical NFT. The rate of ventricular CSF volume increase was related to both cortical NFT and SP. The last hippocampal volume prior to death was related to hippocampal NFT burden; the rate of hippocampal volume atrophy was not related to hippocampal NFT pathology. These significant relationships continue to exist when all nondemented subjects are excluded from analysis. In subjects with cognitive impairment, the best predictor of cortical NFT and SP is the rate of ventricular volume increase. Excluding subjects with long duration between MRI and death did not appreciably alter results.

CONCLUSIONS

MRI volumes measured over time are valid biomarkers of pathologic progression of AD across a range of antemortem clinical states. The rate of ventricular volume enlargement can be used to monitor disease progression or response to treatment in future clinical trials that are targeted at NFT and SP pathology.

Metastases to the breast revisited: radiological-histopathological correlation

Metastases to the breast from extramammary tumours are infrequent. The main challenge in diagnosis is differentiating them from primary breast cancer. Radiologically this can be difficult as there are no specific imaging characteristics for metastases to the breast. Cytopathological evaluation, as well as full radiological assessment, is vital to avoid unnecessary surgery. Sources of primary tumours include a wide variety of cancers. In this pictorial review we illustrate a number of the commonest sources of primary tumours including lymphoma, lung, ovarian and cervical carcinoma, intestinal carcinoid and rare cases of Ewing's sarcoma and malignant pigmented melanocytic schwannoma (low-grade malignant melanoma).

Natural history of cognitive decline in the old old

OBJECTIVE

To prospectively examine the occurrence and outcome of cognitive decline in healthy, community-dwelling elders.

METHODS

Ninety-five elders (mean age 84 years) who at entry had no cognitive impairment were followed for up to 13 years. Cognitive decline was defined as obtaining either a Clinical Dementia Rating (CDR) = 0.5 or Mini-Mental State Examination (MMSE) score < 24 on two examinations.

RESULTS

Three outcomes of aging were determined: intact cognition, persistent cognitive decline without progression to dementia, and dementia. Whereas 49% remained cognitively intact, 51% developed cognitive decline. Mean follow-up to first CDR 0.5 was 3.8 years and age at conversion was 90.0 years. Those who remained cognitively intact had better memory at entry and were less likely to have APOE4 than those who developed cognitive decline. Of the 48 participants with cognitive decline, 27 (56%) developed dementia (CDR > or =1) a mean of 2.8 years later. Participants with cognitive decline who progressed to dementia had poorer confrontation naming at the time of their first CDR 0.5 than those with persistent cognitive decline who did not progress during follow-up.

CONCLUSION

The old old are at high risk for developing cognitive decline but many will not progress to dementia in the next 2 to 3 years or even beyond. These findings are important for understanding the prognosis of cognitive decline and for the design of treatment trials for AD. APOE genotype is a risk factor for cognitive decline.

Multidisciplinary rehabilitation for people with Parkinson's disease: a randomised controlled study

OBJECTIVE

To determine whether a programme of multidisciplinary rehabilitation and group support achieves sustained benefit for people with Parkinson's disease or their carers.

METHODS

The study was a randomised controlled crossover trial comparing patients and carers who had received rehabilitation four months before assessment with those who had not. Patients were recruited from a neurology clinic, attended a day hospital from home weekly for six weeks using private car or hospital transport, and received group educational activities and individual rehabilitation from a multidisciplinary team. Patients were assessed at entry and at six months using a 25 item self assessment Parkinson's disease disability questionnaire, Euroqol-5d, SF-36, PDQ-39, hospital anxiety and depression scale, and timed stand-walk-sit test. Carers were assessed using the carer strain index and Euroqol-5d.

RESULTS

144 people with Parkinson's disease without severe cognitive losses and able to travel to hospital were registered (seven were duplicate registrations); 94 had assessments at baseline and six months. Repeated measures analysis of variance comparing patients at the 24 week crossover point showed that those receiving rehabilitation had a trend towards better stand-walk-sit score (p = 0.093) and worse general and mental health (p = 0.002, p = 0.019). Carers of treated patients had a trend towards more strain (p = 0.086). Analysis comparing patients before and six months after treatment showed worsening in disability, quality of life, and carer strain.

CONCLUSIONS

Patients with Parkinson's disease decline significantly over six months, but a short spell of multidisciplinary rehabilitation may improve mobility. Follow up treatments may be needed to maintain any benefit.

Statin use, hyperlipidaemia, and the risk of breast cancer

Hydroxymethyl glutaryl coenzyme A inhibitors ("statins") are carcinogenic in rodents and an increased incidence of breast cancer was reported among pravastatin users in one randomised trial. We conducted a case-control study in the General Practice Research Database to evaluate the risk of breast cancer among 50- to 79-year old women treated with statins for hyperlipidaemia. Case and control women were matched by age, general practice, duration of prescription history in the General Practice Research Database, and index date. Adjusting for history of benign breast disease, body mass index, and use of hormone replacement therapy, women currently treated with statins had an estimated relative risk for breast cancer of 1.0 (95% confidence interval 0.6-1.6) compared to women without hyperlipidaemia. Untreated hyperlipidaemia was associated with an increased risk of breast cancer (estimated relative risk 1.6; 95% confidence interval 1.1-2.5). The estimated relative risk among women currently receiving only non-statin lipid-lowering drugs was similar to that of women with untreated hyperlipidaemia (1.8; 95% confidence interval 0.9-3.4). We found no evidence for an increasing trend in breast cancer risk with increasing duration of statin use (median duration 1.8 years, maximum 8.6 years).

Redesigning geriatric healthcare: how cross-functional teams and process improvement provide a competitive advantage

This study examines the consequences of adding a geriatric subacute unit to the traditional health care mix offered by a nonprofit hospital. Historically, geriatric health care offerings have been limited to either acute care units or long-term care facilities. The study's findings demonstrate that the addition of a subacute unit that is operated by an interdisciplinary team is a competitively rational move for two reasons. First, it provides a continuum of care that integrates services and departments, thereby reducing costs. Second, it provides a supportive environment for patients and their families. As a consequence patients have a higher probability of returning home than patients who are assigned to more traditional modes of care.

HLA-A2 homozygosity but not heterozygosity is associated with Alzheimer disease

AD is associated with the A2 allele of the human leukocyte antigen (HLA). However, it is not currently known whether there is any difference between A2 homozygotes and A2 heterozygotes. The authors studied 458 patients with AD and found that A2 homozygotes had earlier onset of AD than either A2 heterozygotes (5.4 years, p = 0.002) or those without A2 (5.2 years, p = 0.003). The "recessive" nature of this association suggests that loss of function at the HLA-A locus or a closely linked gene is associated with AD.

Soft tissue uptake on 99mTc methylene diphosphonate bone scan imaging: pictorial review

99mTechnetium methylene diphosphonate (MDP) bone isotope may accumulate in many extra-osseous sites due to a variety of both benign and malignant conditions. This finding on a bone scan can be crucial to the diagnosis and may not be apparent in other imaging or the clinical evaluation of the patient. We present a pictorial review sampling some of the many causes of extra-osseous 99mTc MDP accumulation.

A videotaped CIBIC for dementia patients: validity and reliability in a simulated clinical trial

BACKGROUND

The global impression of a clinician is an Food and Drug Administration--mandated primary outcome measure for clinical trials in dementia. Reliability and validity of these measures are not well established.

METHODS

A videotaped version of the Clinician's Interview Based Impression of Change (CIBIC) was evaluated. Raters were informed that the videotaped interviews were taken at baseline and 6 to 12 months later, when in fact half of the interviews were shown in reverse order. Ratings on "true order" interviews were compared with ratings on "reverse order" interviews. In addition, ratings by neurologists experienced in dementia were compared with those of less experienced raters.

RESULTS

Inter-rater reliability of the neurologists was poor when measured by absolute agreement on a 7-point scale (kappa = 0.18). With a less stringent 3-point scale (better, worse, or unchanged), inter-rater reliability was significantly better for the true order videos (kappa = 0.51) than for the reversed order videos (kappa = 0.12). Validity also was reduced in the reverse order group: neurologists rated 90% of subjects correctly in the "true order" group and 63% correctly in the "reversed order" group. The inter-rater reliability of the neurologists was greater than the less experienced raters, but the validity of the neurologists' ratings was only marginally better.

CONCLUSIONS

The reliability and validity of the videotape CIBIC are reasonable when patients follow the expected course of gradual decline, but are poor when patients appear to improve. These findings suggest that global assessments should be modified as outcome measures in clinical trials with patients with dementia.

Context processing in older adults: evidence for a theory relating cognitive control to neurobiology in healthy aging

A theory of cognitive aging is presented in which healthy older adults are hypothesized to suffer from disturbances in the processing of context that impair cognitive control function across multiple domains, including attention, inhibition, and working memory. These cognitive disturbances are postulated to be directly related to age-related decline in the function of the dopamine (DA) system in the prefrontal cortex (PFC). A connectionist computational model is described that implements specific mechanisms for the role of DA and PFC in context processing. The behavioral predictions of the model were tested in a large sample of older (N = 81) and young (N = 175) adults performing variants of a simple cognitive control task that placed differential demands on context processing. Older adults exhibited both performance decrements and, counterintuitively, performance improvements that are in close agreement with model predictions.

Genetic research on the UK population--do new principles need to be developed?

Governments around the world are beginning to generate population databases as resources for genetic research. In the UK, a proposal has been tabled that plans to incorporate National Health Service information--a move that will effectively create a database of around 60 million. However, this new population collection will not conform to standards established by other national genetic databases, and the UK government report has not accounted for key ethical issues.

Acetaminophen and the risk of renal and bladder cancer in the general practice research database

We conducted a nested, matched case-control study in the General Practice Research Database (GPRD) to assess whether acetaminophen use is associated with renal or bladder cancer. We matched 109 cases of renal cancer and 189 cases of bladder cancer with up to 4 controls each by age, sex, general practice, duration of drug history in the GPRD, and index date. We found that use of acetaminophen from 1 to 5 years before the index date was associated with an increased risk of renal cancer, with a direct relation between risk and number of prescriptions and an adjusted odds ratio of 2.3 (95% CI 1.0-5.3) for subjects with 20 or more prescriptions. There was no evidence for an increase in risk of bladder cancer with acetaminophen use. We found no association between use of non-steroidal anti-inflammatory drugs and either renal or bladder cancer. These results support previous findings from our group and are consistent with a slight increase in the risk of renal cancer, but not bladder cancer, with heavy acetaminophen use.

Selective preservation and degeneration within the prefrontal cortex in aging and Alzheimer disease

BACKGROUND

The prefrontal cortex (PFC) is a heterogeneous cortical structure that supports higher cognitive functions, including working memory and verbal abilities. The PFC is vulnerable to neurodegeneration with healthy aging and Alzheimer disease (AD).

OBJECTIVE

We used volumetric magnetic resonance imaging to determine whether any region within the PFC is more vulnerable to deterioration with late aging or AD.

METHODS

Volumetric analysis of PFC regions was performed on younger healthy elderly subjects (n = 26; 14 men and 12 women [mean age, 71.7 years] for aging analysis; 12 men and 14 women [mean age, 71.4 years] for AD analysis), oldest healthy elderly (OHE) subjects (n = 22 [11 men and 11 women]; mean age, 88.9 years), and patients with AD (n = 22 [12 men and 10 women]; mean age, 69.8 years).

RESULTS

The OHE subjects had less PFC white matter than did young healthy elderly subjects. The orbital region was selectively preserved relative to other PFC regions in the OHE subjects. Subjects with AD had less total PFC gray matter than did age-matched healthy subjects and significantly less volume in the inferior PFC region only.

CONCLUSIONS

Orbital PFC is selectively preserved in OHE subjects. In contrast, degeneration within the PFC with AD is most prominent in the inferior PFC region. Thus, degeneration within the PFC has a regionally distinct pattern in healthy aging and AD.

Requirement for sustained MAPK signaling in both CD4 and CD8 lineage commitment: a threshold model

Although there is general agreement that the RAS/MAPK signaling pathway is required for positive selection of CD4 T cells in the thymus, the role of this pathway in CD8 lineage commitment remains controversial. We show here that the differentiation of isolated cultured thymocytes to the CD8 as well as CD4 T cell lineage is sensitive to MEK inhibition and that both CD4 and CD8 thymocyte differentiation requires sustained MEK signaling. However, CD4 lineage commitment is promoted by a stronger stimulus for longer duration than required for CD8 lineage commitment. Interestingly, CD4 lineage commitment is not irreversibly set even after 10 h of signaling, well past early changes in gene expression. These findings are presented in the context of a model of lineage commitment in which a default pathway of CD8 lineage commitment is altered to CD4 commitment if the thymocyte achieves a threshold level of active MAPK within a certain time frame.

Memory testing in dementia: how much is enough?

Analyses of eight widely used memory measures (Word List Acquisition and Recall used in the Alzheimer's Disease Assessment Scale and the Consortium to Establish a Registry for Alzheimer's Disease neuropsychology battery, Wechsler Memory Scale-Revised [WMS-R] Logical Memory I and II, WMS-R Visual Reproduction I and II, the memory scores from the Neurobehavioral Cognitive Status Examination [NCSE], memory scores from the Mini-Mental State Examination [MMSE]), and the MMSE total score showed each to have moderate predictive power in differentiating between patients with mild dementia and healthy normal controls. When these instruments were combined in a logistic regression analysis, three of them had substantial predictive power. Together, the Word List Acquisition, WMS-R Logical Memory II, and WMS-R Visual Reproduction II were 97.26% accurate (100% sensitive and 94.59% specific) in distinguishing these two groups. The Word List Acquisition is a brief test that alone had high accuracy (92%). These memory tests are highly useful in the diagnosis of mild dementia.