Breath-figure polymer films with local microporosity controlled via spatio-thermal templating.

Porous structures offer a vast range of important industrial applications. In the context of medicine, and specifically in the area of controlled drug delivery, spatial [and temporal] control over local porosity has a significant influence on net molecular flux through [membrane-based] controlled release platforms. Such systems may be formulated as oral, transdermal, or even implantable entities, and address chronic infusion needs covering such ailments as diabetes, cancer and hypertension [1]. In all the aforementioned situations, a facility to spatially control porosity could offer significant advantage, such as safer controlled release over extended durations. Here, we describe a novel route to engineering-in such flexibility within polymeric thin films by modifying spin-coating protocols to accommodate breath film patterning, that is, the spatially controlled condensation of pore forming droplets onto a liquid-polymer film. Upon film solidification, characterization via optical- and scanning probe microscopy revealed that local variations in porosity, as inferred from topographic measurements, could be effectively controlled through provision of an embossed vacuum holding chuck that effectively retains intimate thermal contact with the film substrate during forming. Parallel measurements using real time thermography support the hypothesis that porosity is controlled by local solvent evaporation rates.

APOE genotype influences acquisition and recall following traumatic brain injury.

APOE has been demonstrated to influence traumatic brain injury (TBI) outcome. The relationship between APOE genotype and memory following TBI was examined in 110 participants in the Defense and Veterans' Head Injury Program. Memory performance was worse in those who had an APOE epsilon 4 allele (n = 30) than those who did not (n = 80), whereas genotype groups did not differ on demographic or injury variables or on measures of executive functioning. These data support a specific role for the APOE protein in memory outcome following TBI, and suggest an APOE isoform-specific effect on neuronal repair processes.

Cholesterol accumulates in senile plaques of Alzheimer disease patients and in transgenic APP(SW) mice.

Mounting evidence suggests that cholesterol may contribute to the pathogenesis of Alzheimer disease (AD). We examined whether cholesterol might be present in senile plaques, a hallmark neuropathological feature of AD. We employed 2 different fluorometric-staining techniques (filipin staining and an enzymatic technique) for the determination of cholesterol in brains of postmortem confirmed AD patients and in nondemented, age-matched histopathologically normal controls. AD patient brains showed abnormal accumulation of cholesterol in congophilic/birefringent dense cores of senile plaques that was essentially absent in histopathologically normal controls. To determine whether increased senile plaque-associated cholesterol occurred generally in all plaques or was restricted to a specific subset, quantitative analysis was performed. Data indicate abnormal accumulation of cholesterol in cores of mature plaques but not in diffuse or immature plaques. Additionally, transgenic mice that overexpress the "Swedish" amyloid precursor protein (Tg APP(SW), line 2576) exhibited a similar pattern of abnormal cholesterol accumulation in mature, congophilic amyloid plaques at 24 months of age that was absent in their control littermates or in 8-month-old Tg APP(SW) mice (an age prior to amyloid deposition). Taken together, our results imply a link between cholesterol and AD pathogenesis and suggest that cholesterol plays an important role in the formation and/or progression of senile plaques.

Association between Alzheimer's disease and a functional polymorphism in the Myeloperoxidase gene.

A polymorphism in the Myeloperoxidase gene (MPO) has previously been demonstrated to be associated with gender-specific risk in an Alzheimer's Disease (AD) autopsy sample. We have investigated this polymorphism in our own samples of 226 Caucasian cases and 166 controls and 59 Hispanic cases and 75 controls. In Caucasians we find a significant association between MPO genotype and AD (P = 0.03), although we do not observe any effects of gender or any interaction with the APOE gene. Specifically, the MPO GG genotype contributes a 1.57-fold increased risk for AD. In Hispanics there was no effect of MPO genotype, or of MPO genotype in interaction with age or gender, on diagnosis of AD.

A polymorphism in the cystatin C gene is a novel risk factor for late-onset Alzheimer's disease.

OBJECTIVE: To investigate whether or not a coding polymorphism in the cystatin C gene (CST3) contributes risk for AD. DESIGN: A case-control genetic association study of a Caucasian dataset of 309 clinic- and community-based cases and 134 community-based controls. RESULTS: The authors find a signficant interaction between the GG genotype of CST3 and age/age of onset on risk for AD, such that in the over-80 age group the GG genotype contributes two-fold increased risk for the disease. The authors also see a trend toward interaction between APOE epsilon4-carrying genotype and age/age of onset in this dataset, but in the case of APOE the risk decreases with age. Analysis of only the community-based cases versus controls reveals a significant three-way interaction between APOE, CST3 and age/age of onset. CONCLUSION: The reduced or absent risk for AD conferred by APOE in older populations has been well reported in the literature, prompting the suggestion that additional genetic risk factors confer risk for later-onset AD. In the author's dataset the opposite effects of APOE and CST3 genotype on risk for AD with increasing age suggest that CST3 is one of the risk factors for later-onset AD. Although the functional significance of this coding polymorphism has not yet been reported, several hypotheses can be proposed as to how variation in an amyloidogenic cysteine protease inhibitor may have pathologic consequences for AD.

The genetic association between Cathepsin D and Alzheimer's disease.

The aspartyl protease Cathepsin D has previously been suggested to play a role in the Alzheimer's disease (AD) process because of its ability to cleave the beta-amyloid precursor protein and the possibility that it may be one of the 'secretase' enzymes. A functional C-->T polymorphism in the Cathepsin D gene (CATD) has been reported to be associated with increased risk for AD in Caucasian case-control studies; specifically, the T-carrying genotypes confer increased risk. We have examined this association in our own Caucasian dataset of 210 AD cases and 120 controls, and in an additional Hispanic dataset comprising 79 AD cases and 112 controls. In Hispanics we find a modest interaction between CATD genotype and age of onset on risk for AD, such that the non-T-carrying genotype confers increased risk. In our Caucasian dataset we find no evidence for association between the CATD polymorphism and AD, although we do observe a small tendency towards an increase in the T-carrying genotypes in the case group, consistent with previous studies. We conducted an aggregate analysis of the published Caucasian datasets and found evidence that this CATD polymorphism (or another locus in linkage disequilibrium) does contribute significant, but small (<2%) risk for AD.

Family history of dementia and current depression in nondemented community-dwelling older adults.

Since it has been postulated that mood disturbance in nondemented older adults may represent a prodromal feature of dementia for a subgroup of patients, it would be expected that patients with these symptoms would evidence a greater prevalence of family history of dementia. In a sample of 3225 community-dwelling cognitively intact elderly recruited from a free memory-screening program, we found that current depression was more common in participants with a positive versus a negative family history of dementia in first-degree relatives (17% versus 11%; Fisher's Exact Test, P < .0001). This relationship remained significant after controlling for age, education, gender, ethnicity, and Folstein Mini-Mental State Examination score (OR = 1.5; 95% CI = 1.2-1.9, Wald X2 = 15.5, P < .001). The results suggest that symptoms of depression may herald the onset of an incipient dementia syndrome in a subset of geriatric patients. Alternatively, the results may be indicative of familial aggregation of dementia and depression.

Progressive and gender-dependent cognitive impairment in the APP(SW) transgenic mouse model for Alzheimer's disease.

To determine if early cognitive sensorimotor deficits exist in APP(SW) transgenic mice overexpressing human amyloid precursor protein (APP). Tg+ and Tg- animals at both 3 and 9 months of age (3M and 9M, respectively) were evaluated in a comprehensive battery of measures. The performance of all Tg+ mice at both ages was no different from all Tg- controls in Y-maze alternations, water maze acquisition, passive avoidance, and active avoidance testing. By contrast, results from other tasks revealed substantive cognitive deficits in Tg+ mice that were usually gender-dependent and sometimes progressive in nature. Between 3M and 9M, a progressive impairment was observed in circular platform performance by Tg+ males, as was a progressive deficit in visible platform testing for all Tg+ animals. Other transgenic effects included both impaired water maze retention and circular platform performance in 3M Tg+ females; this later effect was responsible for an overall (males + females) Tg+ deficit in circular platform performance at 3M. Sensorimotor testing revealed several Tg+ effects, most notably an increased activity of Tg+ males in both open field and Y-maze at 3M. Significant correlations between a number of behavioral measures were observed, although factor analysis suggests that each task measured components of sensorimotor/cognitive function not measured by other tasks. Finally, Tg+ mice had lower survivability than Tg- animals through 9M (85 vs. 96%). In summary, these results demonstrate the presence of gender-related and progressive cognitive deficits in APP(SW) transgenic mice at a relatively early age (i.e., prior to overt, beta-amyloid deposition in the brain), suggesting a pathophysiologic role for elevated levels of 'soluble' beta-amyloid in such impairments.

Adaptation of the circular platform spatial memory task for mice: use in detecting cognitive impairment in the APP(SW) transgenic mouse model for Alzheimer's disease.

A methodology is described for use of a 16-hole circular platform task to test spatial memory in mice. Both bright light and a fan were used to motivate mice to escape the platform surface through a single hole containing an attached escape box. For each daily trial, three correlated measures (escape latency, number of errors, and error rating) comprehensively evaluated cognitive performance. In an initial study, the 'spatial' nature of this task was demonstrated by the much poorer performance of non-transgenic mice when visual cues are removed. Behavioral sensitivity of the circular platform task was then shown through its ability to discern cognitive impairment in 7-month-old transgenic mice, carrying the mutant APP(SW) gene for early-onset Alzheimer's disease in humans, from non-transgenic litter-mates. Since there are currently only a few tasks available to definitively test cognitive performance in mice, the circular platform task offers a versatile, multiple-measure option with numerous advantages. Particularly in view of the increasing number of genetically manipulated mouse models being produced, the circular platform task should be most useful in providing a sensitive evaluation of cognition in mice.

Newly described form of X-linked arthrogryposis maps to the long arm of the human X chromosome.

Arthrogryposis is a heterogeneous birth defect characterized by limitation of movement at multiple joints. One in 3,000 infants is born with arthrogryposis, and at least a third of these cases have a genetic cause. Four distinct types of X-linked arthrogryposis have been reported, and a severe lethal form recently was mapped to Xpll.3-qll.2. We now report an extended family affected with a novel variant of X-linked arthrogryposis that involves only the lower limbs. Linkage analysis with polymorphic DNA markers maps the disease locus in this unique family to the long arm of the human X chromosome between DXS1220 and DXS1205 in Xq23-27.

Confirmation of the localization of the human GABAA receptor alpha 1-subunit gene (GABRA1) to distal 5q by linkage analysis.

The GABAA receptor is the major inhibitory neurotransmitter receptor in the mammalian brain. To date, 14 genes that encode subunits of this receptor have been identified; these appear to be scattered throughout the human genome and are under investigation as candidate loci for a number of neurological and psychiatric disorders. We report here a highly polymorphic (dC-dA)n repeat within the human alpha 1-subunit gene (GABRA1). Typing of this marker in the Centre d'Etude du Polymorphisme Humain (CEPH) panel of families confirms the previous assignment of the GABRA1 locus to the distal portion of chromosome 5q by demonstrating linkage to the markers CRI-L45 (D5S61) (Zmax = 11.00, theta max = 0.15), CRI-V1022 (D5S54) (Zmax = 7.25, theta max = 0.20), and CRI-P148 (D5S72) (Zmax = 5.71, theta max = 0.24).

Association between autoimmune thyroid disease and familial Alzheimer's disease.

OBJECTIVE: To determine the prevalence of autoimmune thyroid disease in Familial Alzheimer's Disease kindreds and to ascertain whether there is any evidence for genetic linkage between the two conditions. DESIGN: Retrospective study of Familial Alzheimer's Disease kindreds. PATIENTS: Seventy affected and unaffected family members from 12 kindreds. MEASUREMENTS: Anti-thyroglobulin and anti-microsomal autoantibody status was determined using an enzyme-linked immunosorbent assay. Thyrotrophin levels were determined by an immunoradiometric assay. RESULTS: Of the family members, 41.4% had evidence of autoimmune thyroid disease, with significant co-segregation between the presence of thyroid autoantibodies and the development of Alzheimer's disease (P less than 0.01). CONCLUSIONS: This study demonstrates a very high prevalence of autoimmune thyroid disease in Familial Alzheimer's Disease kindreds and suggests that a genetic factor contributing towards the development of autoimmune thyroid disease may be located on chromosome 21 within close proximity to the Familial Alzheimer's Disease gene.

Evidence for allelic heterogeneity in familial early-onset Alzheimer's disease.

Age of onset was examined for 139 members of 30 families affected by early-onset AD. Most (77%) of the variance of age of onset derived from differences between rather than within families. The constancy of age of onset within families was also observed in an analysis restricted to families derived from a population-based epidemiological study with complete ascertainment of early-onset AD. Furthermore, we observed clustering of age of onset within those families that support linkage to the predisposing locus on chromosome 21. Our data are compatible with the view that allelic heterogeneity at the AD locus may account for the similarity in age of onset within families. This finding may be of value for scientific studies of AD as well as for genetic counselling.

Specialist versus general practitioner treatment of problem drinkers.

The efficacy of specialist versus general practitioner (GP) treatment of problem drinkers was assessed in a randomised controlled trial. 40 problem drinkers referred consecutively to a specialist alcohol clinic by their GP were, after assessment, randomly allocated to either GP or specialist clinic treatment groups. All subjects received initial advice and counselling in the clinic about their drinking. The specialist clinic group received continued care from the clinic including, if necessary, admission to hospital. Patients in the GP group were returned to the care of the GP who was contacted and supported by the specialist. After 6 months of follow-up, there were significant reductions in alcohol consumption and alcohol-related problems in both groups. No significant difference was found between the two groups with respect to the main outcome measures. No differential treatment effect was found with the more severely dependent drinkers. The findings show that after an initial detailed assessment and advice session, the treatment provided by GPs is at least as effective as that from a specialist clinic with respect to improvements in drinking behaviour and alcohol-related problems. After initial assessment and advice, specialist clinics should encourage GPs to become more involved in the subsequent care of problem drinkers. Such a practice should be based on the individual patient's needs and the adequacy of support offered to GPs.

Prion dementia without characteristic pathology.

Gerstmann-Sträussler syndrome (GSS) was diagnosed in a family with presenile dementia by prion protein gene analysis. Extensive histological examination of the brain of an affected individual from this family showed no characteristic features of GSS or Creutzfeldt-Jakob disease (CJD). Thus "spongiform encephalopathy" (GSS or CJD) cannot always be excluded on neuropathological grounds in an individual dying of a dementing condition, and the true prevalence of these diseases is likely to be underestimated. Screening by prion protein gene analysis will help to determine the full clinical and neuropathological phenotype in familial cases. This observation may be relevant to the assessment of possible transmission of bovine spongiform encephalopathy to man.

Transmission and age-at-onset patterns in familial Alzheimer's disease: evidence for heterogeneity.

We evaluated age at onset and lifetime risk for Alzheimer's disease (AD) in 70 kindreds with familial AD (designated FAD) composed of 541 affected and 1,066 unaffected offspring of demented parents who were identified retrospectively. Using a survival analysis method which takes into account affected persons with unknown onset ages and unaffected persons with unknown censoring ages, we found lifetime risk of AD among at-risk offspring by age 87 to be 64%. Analysis of age at onset among kindreds showed evidence for a bimodal distribution: in this sample, families with a mean onset age of less than 58 years were designated as having early-onset, while late-onset families had a mean onset age greater than 58 years. At-risk offspring in early-onset families had an estimated lifetime risk for dementia of 53%, which is significantly less than the risk of 86% that was estimated for offspring in late-onset families. Men and women in early-onset families had equivalent risk of dementia. In late-onset families, the risk to female offspring was somewhat higher than to male offspring but this difference was marginally significant. Lifetime risk of dementia in early-onset FAD kindreds is consistent with an autosomal dominant inheritance model. Our results may suggest that late-onset FAD has at least 2 etiologies; AD in some families may be transmitted as a dominant trait, whereas a proportion of cases in these and other late-onset families may be caused by other genetic or shared environmental factors.

The role of genetic factors in the etiology of the affective disorders.

Recent application of genetic linkage analysis to the affective disorders has suggested that there are at least three genotypic forms. This is an important step toward defining the genetic etiology involved, as it had previously been suggested that the complex nature of the clinical phenotype would preclude any attempt to apply such a technique. However, to date no clinical evidence exists to discriminate these genotypes at the phenotypic level. Molecular geneticists now face a formidable task of identifying the aberrant gene and relating the gene product, a protein, to the observed psychopathology. Current molecular genetic research in the affective disorders is discussed and similar work applied to the study of nonpsychiatric disorders such as cystic fibrosis and Duchenne muscular dystrophy is reviewed. The clinical value of genetic risk analysis for individuals with a family history of the affective disorders is also considered.