Promising Targets for the Treatment of Neurodegenerative Diseases.

Genetics and pathology have proven to be an effective combination to identify an evolving and deepening landscape of pathways and potential therapeutic targets in neurodegenerative diseases. Initially this landscape appeared to be populated with distinct therapeutic targets but with potentially overlapping mechanisms in each neurodegenerative disease. Our understanding has expanded to recognize that multiple pathologies are common in neurodegenerative disease, and that there is considerable overlap in pathways and targets driving neurodegenerative diseases. This potentially opens the way for future treatments to be indicated by tissue pathology and genetic basis rather than clinical phenotype. The potential to treat neurodegenerative disease by addressing underlying pathophysiology is still in the early days and challenges remain, especially the likely need to address pathologies early in disease. This will require redefinition of diagnosis and the tools to enable earlier diagnosis.

What factors are associated with physical activity in older people, assessed objectively by accelerometry?

OBJECTIVES: To assess physical activity (PA) levels measured objectively using accelerometers in community-dwelling older people and to examine the associations with health, disability, anthropometric measures and psychosocial factors. DESIGN: Cross-sectional survey. SETTING: Single general practice (primary care centre), United Kingdom. PARTICIPANTS: Random selection of 560 community-dwelling older people at least 65 years old, registered with the practice. 43% (238/560) participated. ASSESSMENT OF RISK FACTORS: Participants completed a questionnaire assessing health, disability, psychosocial factors and PA levels; underwent anthropometric assessment; and wore an accelerometer (Actigraph) for 7 days. MAIN OUTCOME MEASURES: Average daily accelerometer step-counts and time spent in different PA levels. Associations between step-counts and other factors were examined using linear regression. RESULTS: Average daily step-count was 6443 (95% CI 6032 to 6853). Men achieved 754 (84 to 1424) more steps daily than women. Step-count declined steadily with age. Independent predictors of average daily step-count were: age; general health; disability; diabetes; body mass index; exercise self-efficacy; and perceived exercise control. Activities associated independently with higher step-counts included number of long walks and dog-walking. Only 2.5% (6/238) of participants achieved the recommended 150 minutes weekly of at least moderate-intensity activity in > or = 10 minute bouts; 62% (147/238) achieved none. CONCLUSIONS: This is the first population-based sample of older people with objective PA and anthropometric measures. PA levels in older people are well below recommended levels, emphasising the need to increase PA in this age group, particularly in those who are overweight/obese or have diabetes. The independent effects of exercise self-efficacy and exercise control on PA levels highlight their role as potential mediators for intervention studies.

Assembly of glycoprotein-80 adhesion complexes in Dictyostelium. Receptor compartmentalization and oligomerization in membrane rafts.

The phospholipid-anchored membrane glycoprotein (gp)-80 mediates cell-cell adhesion through a homophilic trans-interaction mechanism during Dictyostelium development and is enriched in a Triton X-100-insoluble floating fraction. To elucidate how gp80 adhesion complexes assemble in the plasma membrane, gp80-gp80 and gp80-raft interactions were investigated. A low density raft-like membrane fraction was isolated using a detergent-free method. It was enriched in sterols, the phospholipid-anchored proteins gp80, gp138, and ponticulin, as well as DdCD36 and actin, corresponding to components found in the Triton X-100-insoluble floating fraction. Chemical cross-linking revealed that gp80 oligomers were enriched in the raft-like membrane fraction, implicating stable oligomer-raft interactions. However, gp80 oligomers resisted sterol sequestration and were partially dissociated with Triton X-100, suggesting that compartmentalization in rafts was not solely responsible for their formation. The trans-dimer known to mediate adhesion was identified, but cis-oligomerization predominated and displayed greater accumulation during development. In fact, oligomerization was dependent on the level of gp80 expression and occurred among isolated gp80 extracellular domains, indicating that it was mediated by direct gp80-gp80 interactions. Rafts existed in gp80-null cells and such pre-existent membrane domains may provide optimal microenvironments for gp80 cis-oligomerization and the assembly of adhesion complexes.

Differences in hormone replacement therapy use by social class, region and psychological symptoms.

OBJECTIVE: To describe the relationship between socio-demographic factors, heart disease risk factors, psychological symptoms and the use of hormone replacement therapy by English women. DESIGN: Cross-sectional analysis of a population-based survey. SETTING: England. POPULATION: 13,214 women aged 40-69 years who participated in the nurse-administered schedule of the Health Survey for England between 1993 and 1996. OUTCOME: Current hormone replacement therapy use. RESULTS: Women from social classes II and I and women who live in the south of England were more likely to use hormone replacement therapy independently of a range of socio-demographic factors including education. The adjusted odds ratio for social classes II and I compared with social classes IV and V was 1.51 (95% CI 1.20 to 1.91) and for women in the South of England was 1.38 (95% CI 1.18 to 1.62). Women with a history of heart disease and those with high cholesterol levels were less likely to use hormone replacement therapy. Women with psychological symptoms were more likely to be prescribed hormone replacement therapy, as were those who had recently seen a doctor. CONCLUSION: There is marked socio-demographic inequity in use of hormone replacement therapy. This may accentuate existing inequalities in health and reduce any potential benefits of Hormone Replacement Therapy for public health. The relationship between psychological symptoms, use of medical services and use of hormone replacement therapy suggests that hormone replacement therapy is prescribed for the management of psychological symptoms.

Do income questions and seeking consent to link medical records reduce survey response rates? A randomised controlled trial among older people.

Traditional measures of socioeconomic status may not be reliable for older people and income may be a useful measure for research into inequalities in health. At the same time, researchers increasingly wish to link survey findings to individual data taken from medical records. For this, consent must be sought. To examine whether questions on household income and seeking consent for medical record linkage affected response rates, a postal health survey of patients aged 65 to 74 was undertaken in an inner London practice. The overall response rate was 62.8%. In this study, the inclusion of an income question or seeking consent to access medical records did not reduce response rates to a health survey among older people.

Involvement of a triton-insoluble floating fraction in Dictyostelium cell-cell adhesion.

We have isolated and characterized a Triton-insoluble floating fraction (TIFF) from Dictyostelium. Ten major proteins were consistently detected in TIFF, and six species were identified by mass spectrometry as actin, porin, comitin, regulatory myosin light chain, a novel member of the CD36 family, and the phospholipid-anchored cell adhesion molecule gp80. TIFF was enriched with many acylated proteins. Also, the sterol/phospholipid ratio of TIFF was 10-fold higher than that of the bulk plasma membrane. Immunoelectron microscopy showed that TIFF has vesicular morphology and confirmed the association of gp80 and comitin with TIFF membranes. Several TIFF properties were similar to those of Dictyostelium contact regions, which were isolated as a cytoskeleton-associated membrane fraction. Mass spectrometry demonstrated that TIFF and contact regions shared the same major proteins. During development, gp80 colocalized with F-actin, porin, and comitin at cell-cell contacts. These proteins were also recruited to gp80 caps induced by antibody cross-linking. Filipin staining revealed high sterol levels in both gp80-enriched cell-cell contacts and gp80 caps. Moreover, sterol sequestration by filipin and digitonin inhibited gp80-mediated cell-cell adhesion. This study reveals that Dictyostelium TIFF has structural properties previously attributed to vertebrate TIFF and establishes a role for Dictyostelium TIFF in cell-cell adhesion during development.

Testing drug response in the presence of genetic information: sampling issues for clinical trials.

Progress towards construction of a dense map of di-allelic markers across the human genome has generated considerable enthusiasm for pharmacogenomic applications. To date, however, nearly all of the effort on single nucleotide polymorphism (SNP) projects has been focused on marker identification and screening, not on how the SNP genotype data actually can be used in clinical trials to advance medical practice. Here, we explore how different properties of SNPs impact the size, scope and design of clinical trials using a simple trial design. We evaluate the clinical trial sampling requirements under different allele frequencies, gene action, gene effect size and number of markers in a genome screen. Power and sample size calculations suggest that allele frequency and type of gene action can have a dramatic impact on trial sample sizes, in that under some conditions the required sample sizes are too large to be applicable in a costly clinical trial setting. In other situations, however, pharmacogenomic clinical trials can yield significant sampling/cost savings over traditional trials. These properties are discussed with regard to the general usage of genetic information in clinical trial settings.

Impact of the new American Diabetes Association and World Health Organisation diagnostic criteria for diabetes on subjects from three ethnic groups living in the UK.

BACKGROUND AND AIM: The American Diabetes Association (ADA) recommends basing diabetes diagnosis on a fasting plasma glucose (FPG) of > or = 7.0 mmol/L and impaired fasting glucose (IFG) on 6.1 < or = FPG < 7.0 mmol/L. The new World Health Organisation (WHO) recommendations also adopt this FPG cut-off, but retain the oral glucose tolerance test (OGTT) where possible and the intermediate group of impaired glucose tolerance (IGT) in addition to IFG. We compare the effect of the new ADA and WHO diagnostic criteria in three ethnic groups. METHODS AND RESULTS: Three hundred and eighty whites, 340 South Asians and 347 subjects of African descent, aged 40-59 years and not known to have diabetes, were identified through South London general practices. Inevitably, the prevalence of new diabetes was lower under ADA than under WHO criteria (including post-load levels) for all three groups, falling from 5.7% overall to 3.3% (fall 2.4% 95% CI 1.6% to 3.6%). The largest fall was for South Asians from 9.1% to 5.0% (fall 4.1% 95% CI 2.2% to 6.8%). The prevalence of impaired glucose homeostasis under ADA criteria (IFG) was substantially less than under WHO criteria (IFG + IGT). Under WHO criteria, including a glucose tolerance test, there was marked variation by ethnic group in diabetes prevalence (p < 0.001) and IGT (p < 0.0001), both were most prevalent amongst South Asians. Under ADA criteria, (or new WHO criteria without OGTT) diabetes prevalence still differed significantly between groups (p < 0.01), but there was no difference in IFG prevalence (p = 0.43). CONCLUSIONS: Subjects with IGT but normal FPG are at greater risk of coronary heart disease. The new ADA definition fails to identify substantial numbers of such subjects, particularly among South Asians. Our study supports the retention of the OGTT in the new WHO criteria, particularly for South Asians.

Effects of E-2078, a stable dynorphin A(1-8) analog, on sedation and serum prolactin levels in rhesus monkeys.

RATIONALE: The dynorphins are endogenous opioid peptides with relative binding selectivity for kappa-receptors. It is unclear whether the dynorphins share the pharmacological profile observed with synthetic kappa-agonists in primates. OBJECTIVE: The main objective of this study was to compare the effects of s.c. E-2078, a stable dynorphin A(1-8) analog, with two synthetic kappa-opioid ligands, spiradoline (a reference arylacetamide kappa-agonist) and ICI204,448 (a "peripherally selective" kappa-agonist) in behavioral and neuroendocrine endpoints in rhesus monkeys. METHODS: Dose-effect curves were determined for s.c. E-2078, spiradoline and ICI204,448 in causing overt sedation and muscle relaxation (as detected in observational rating scales), in increasing latency to retrieve and consume a food pellet and in increasing serum levels of the anterior pituitary hormone, prolactin, in intact female rhesus monkeys. RESULTS: E-2078 and ICI204,448 (0.1-3.2 mg/kg) caused increases in sedation and muscle relaxation scores, but were less potent and apparently less effective than spiradoline (0.001-0.1 mg/kg) up to the highest doses presently studied. All three agonists were equieffective and approximately equipotent in increasing the latency to retrieve and consume a pellet. Furthermore, E-2078 (0.001-0.032 mg/kg) was equipotent and equieffective with spiradoline in increasing serum prolactin levels, whereas ICI204,448 was less potent, but slightly more effective than the former two agonists. The effects of E-2078 on serum prolactin levels were surmountably antagonized by quadazocine (1 mg/kg) and naltrexone (0.1 mg/kg). CONCLUSIONS: The present studies show that serum prolactin levels are a highly sensitive, quantitative endpoint to study the potency and effectiveness of systemically administered E-2078, and show that the dynorphins may be potent and effective in causing some, but not all, the effects that are observed after the administration of synthetic kappa-agonists.

Apparent efficacy of kappa-opioid receptor ligands on serum prolactin levels in rhesus monkeys.

These studies investigated whether serum prolactin levels could be a quantitative marker of the apparent efficacy of kappa-opioid receptor ligands in primates. The effects of s.c. bremazocine and U50,488 (trans-(+/-)-3, 4-Dichloro-N-methyl-N-[2-(1-pyrrolidinyl)-cyclohexyl]-benzeneacetamid e; agonists), nalorphine (partial agonist) and nalmefene (antagonist) on prolactin levels were studied in intact female rhesus monkeys. The above compounds, except nalmefene, increased prolactin levels, and their actions conformed to sigmoidal dose-effect curves. The rank order of the compounds' maximum effects in this neuroendocrine endpoint is similar to that in cloned kappa-receptors in vitro, and in a presently studied thermal antinociception assay in vivo. Prolactin may therefore be a quantitative marker of the apparent efficacy of kappa-opioid receptor ligands in primates.

Effects of systemically administered dynorphin A(1-17) in rhesus monkeys.

The effects of i.v. dynorphin A(1-17) and its main nonopioid biotransformation fragment, dynorphin A(2-17), were compared in rhesus monkeys with those of the selective kappa-opioid agonist, U69, 593, in assays of operant behavior, thermal antinociception, and neuroendocrine function (prolactin release). Dynorphin A(1-17) (0. 1-3.2 mg/kg i.v.) and U69,593 (0.001-0.032 mg/kg s.c.) decreased rates of schedule-controlled (fixed ratio 20) food-reinforced responding, whereas dynorphin A(2-17) (1-3.2 mg/kg i.v.) was ineffective. Pretreatment studies with the opioid antagonist quadazocine (0.32 mg/kg s.c.) revealed that the operant effects of dynorphin A(1-17) were not mediated by kappa- or micro-opioid receptors. A different profile was observed in the warm water tail withdrawal assay of thermal antinociception, where both dynorphin A(1-17) and A(2-17) (0.032-3.2 mg/kg i.v., n = 4) were modestly effective in 50 degrees C water, and both were ineffective in 55 degrees C water. By comparison, U69,593 (0.032-0.18 mg/kg s.c.) was maximally effective in 50 degrees C water and partially effective in 55 degrees C. kappa-opioid agonists increase serum levels of prolactin in animals and humans. Dynorphin A(1-17) (ED(50) = 0.0011 mg/kg i.v.), similar to U69,593 (ED(50) = 0.0030 mg/kg i.v.), was very potent in increasing serum prolactin levels in follicular phase female rhesus monkeys, whereas dynorphin A(2-17) (0.32 mg/kg i.v.) was ineffective. The effects of dynorphin A(1-17) and U69,593 on serum prolactin were both antagonized by quadazocine (0.32 mg/kg s.c.) in a surmountable manner, consistent with opioid receptor mediation. The present studies show that serum prolactin levels are a sensitive quantitative endpoint to study the systemic effects of the endogenous opioid peptide, dynorphin A(1-17), in primates.

A genomewide analysis provides evidence for novel linkages in inflammatory bowel disease in a large European cohort.

Inflammatory bowel disease (IBD) is characterized by a chronic relapsing intestinal inflammation, typically starting in early adulthood. IBD is subdivided into two subtypes, on the basis of clinical and histologic features: Crohn disease and ulcerative colitis (UC). Previous genomewide searches identified regions harboring susceptibility loci on chromosomes 1, 3, 4, 7, 12, and 16. To expand our understanding of the genetic risk profile, we performed a 9-cM genomewide search for susceptibility loci in 268 families containing 353 affected sibling pairs. Previous linkages on chromosomes 12 and 16 were replicated, and the chromosome 4 linkage was extended in this sample. New suggestive evidence for autosomal linkages was observed on chromosomes 1, 6, 10, and 22, with LOD scores of 2.08, 2.07, 2.30, and 1.52, respectively. A maximum LOD score of 1.76 was observed on the X chromosome, for UC, which is consistent with the clinical association of IBD with Ullrich-Turner syndrome. The linkage finding on chromosome 6p is of interest, given the possible contribution of human leukocyte antigen and tumor necrosis-factor genes in IBD. This genomewide linkage scan, done with a large family cohort, has confirmed three previous IBD linkages and has provided evidence for five additional regions that may harbor IBD predisposition genes.

Genetic analysis of inflammatory bowel disease in a large European cohort supports linkage to chromosomes 12 and 16.

BACKGROUND & AIMS: Inflammatory bowel disease (IBD) is a complex disorder of unknown etiology. Epidemiological investigations suggest a genetic basis for IBD. Recent genetic studies have identified several IBD linkages. The significance of these linkages will be determined by studies in large patient collections. The aim of this study was to replicate IBD linkages on chromosomes 12 and 16 in a large European cohort. METHODS: Three hundred fifty-nine affected sibling pairs from 274 kindreds were genotyped using microsatellite markers spanning chromosomes 12 and 16. Affection status of the sibling pairs was defined as Crohn's disease (CD) or ulcerative colitis (UC). RESULTS: Nonparametric statistical analyses showed linkage for both chromosomes. Two-point results for chromosome 12 peaked at D12S303 (logarithm of odds [LOD], 2.15; P = 0.003) for CD and at D12S75 (LOD, 0.92; P = 0.03) for UC. Multipoint analyses produced a peak LOD of 1.8 for CD. Chromosome 16 showed linkage for CD at marker D16S415 (LOD, 1.52; P = 0.007). Multipoint support peaked above markers D16S409 and D16S411 (LOD, 1.7). CONCLUSIONS: These data are consistent with linkage of IBD to chromosomes 12 and 16. The replication of genetic risk loci in a large independent family collection indicates important and common susceptibility genes in these regions and will facilitate identification of genes involved in IBD.

Myocardial ischemia alters immunoregulatory cell traffic and function in the rat independent of exogenous catecholamine administration.

Recent investigation has suggested there is an adrenergically-driven efflux of beta 2-receptor rich lymphocyte subsets into the circulation with altered function following either exercise or infusion of exogenous catecholamines. Myocardial ischemia, like exercise, is associated with generalized sympathoadrenal activation. To determine whether ischemia influences immunoregulatory cell traffic and function in a manner comparable to beta 2-adrenergic stimulation via isoproterenol, rats underwent thoracotomy with or without coronary ligation. Another group of rats received either isoproterenol (1 mg/kg) or vehicle (10 mM HCl) intraperitoneally. Thoracotomy, regardless of whether or not myocardial ischemia was induced, led to lymphocytosis, reflected primarily by an increase in Thelper (Th) cells and, to a lesser degree, in Tsuppressor/cytotoxic (Ts/c) and natural killer (NK) cells, with a tendency toward an increased Th/Ts/c ratio. To the contrary, isoproterenol injection resulted in a relative lymphopenia characterized by diminished B and Th cell numbers, preserved Ts/c and increased NK cell numbers leading to a significant decrease in the Th/Ts/c ratio. With respect to splenic composition, 60 but not 15 min of myocardial ischemia led to diminished Th and B cell numbers compared to sham operated controls, whereas isoproterenol appeared to stimulate an efflux of only NK cells. Both ischemia and isoproterenol enhanced basal splenocyte function; however, only ischemia significantly boosted splenocyte responsiveness to the mitogen Concanavalin A. Surgically induced myocardial ischemia leads to alterations in immunoregulatory cell migration and function which are distinct from those found with beta 2-adrenergic stimulation via isoproterenol.

Multiple retiform hemangioendotheliomas. A low-grade angiosarcoma.

We present the case of a 30-year-old woman who over a 10-year period has developed multiple well-differentiated angiosarcomas involving the trunk and extremities. The clinical and histologic features are characteristic of retiform hemangioendothelioma (RH), a distinctive form of low-grade angiosarcoma. This case is unique in that multiple lesions developed in different anatomic sites. We discuss the clinical and histologic characteristics, diagnosis, and prognosis of RH.

Indication for linkage of the human OB gene region with extreme obesity.

Obesity is one of the most significant risk factors for hypertension, coronary heart disease, and NIDDM (Frayn KN, Coppack SW: Insulin resistance, adipose tissue and coronary heart disease. Clin Sci 82:1-8, 1992; Kaplan NM: The deadly quartet: upper-body obesity, glucose intolerance, hypertriglyceridemia, and hypertension. Arch Intern Med 149:1514-1520, 1989). While family segregation, adoption, and twin studies have indicated that degree of adiposity has a significant genetic component (Stunkard AJ, Harris JR, Pedersen NL, McClearn GE: The body-mass index of twins who have been reared apart. N Engl J Med 322:1483-1487, 1990; Bouchard C, Despres J-P, Mauriege P: Genetic and nongenetic determinants of regional fat distribution. Endocr Rev 14:72-93, 1993), the genes and predisposing mutations remain poorly understood. This is in contrast to several well-defined genetic models for obesity in rodents, particularly the mouse obese (ob) gene, in which loss-of-function mutations cause severe obesity. Recent studies have demonstrated a substantial reduction in body fat when recombinant ob protein (leptin) is administered to mice. To test the relevance of these observations to human obesity, the location of the human homologue (OB) was established by radiation hybrid mapping and eight microsatellite markers spanning the OB gene region (7q3l.3) were genotyped in 101 obese French families. Affected-sib-pair analyses for extreme obesity, defined by BMI >35 kg/m2, revealed suggestive evidence for linkage to three markers located within 2 cM of the OB gene (D7S514, D7S680, and D7S530). The OB gene is therefore a candidate for genetic predisposition to extreme obesity in a subset of these families.

System for projection of a three-dimensional, moving virtual target for studies of eye-hand coordination.

Eye-hand tracking of moving visual objects in three-dimensional (3D) space is common in the behavioral repertoire of primates. However, behavioral and/or neurophysiological studies of this function are lacking mainly because devices do not exist that allow its investigation. We describe a device by which a spot of light can be presented in the immediate extrapersonal space of a subject and can be moved in various trajectories in 3D space. The target is a real image of a circular aperture produced by a system consisting of a light source, aperture, filters, several lenses and fold mirrors, and a large concave mirror to focus the final real image. Rapid, computer-controlled movement of the image is obtained by tilting a gimbal-mounted guide mirror (for x and y motion) and by translating a lens (for motion in the z direction). A second configuration of the system allows movement of a 3D image in the 3D space. Hand motion is monitored by means of a sonic, 3D, position-measurement system.