bluuebunny/crossref_metadata_2025 huggingface dataset:
Sustained antibody responses depend on CD28 function in bone marrow–resident plasma cells
Authors: Rozanski Cheryl H. , Arens Ramon , Carlson Louise M. , Nair Jayakumar , Boise Lawrence H. , Chanan-Khan Asher A. , Schoenberger Stephen P. , Lee Kelvin P.
Published: June 2011

Sustained long-term antibody levels are the cornerstone of protective immunity, yet it remains unclear how they are durably maintained. A predominant theory implicates antigen-independent antibody production by a subset of long-lived plasma cells (LLPCs) that survive within bone marrow (BM). Central tenets of this model—that BM LLPCs constitute a subset defined by intrinsic biology distinct from PCs in other tissues and contribute to long-term antibody titers—have not been definitively demonstrated. We now report that long-term humoral immunity depends on the PC-intrinsic function of CD28, which selectively supports the survival of BM LLPC but not splenic short-lived PC (SLPC). LLPC and SLPC both express CD28, but CD28-driven enhanced survival occurred only in the LLPC. In vivo, even in the presence of sufficient T cell help, loss of CD28 or its ligands CD80 and CD86 caused significant loss of the LLPC population, reduction of LLPC half-life from 426 to 63 d, and inability to maintain long-term antibody titers, but there was no effect on SLPC populations. These findings establish the existence of the distinct BM LLPC subset necessary to sustain antibody titers and uncover a central role for CD28 function in the longevity of PCs and humoral immunity.
Prevention of type 1 diabetes in mice by tolerogenic vaccination with a strong agonist insulin mimetope
Authors: Daniel Carolin , Weigmann Benno , Bronson Roderick , von Boehmer Harald
Published: June 2011

Type 1 diabetes (T1D) results from the destruction of insulin-secreting pancreatic β cells by autoreactive T cells. Insulin is an essential target of the autoimmune attack. Insulin epitopes recognized by diabetogenic T cell clones bind poorly to the class II I-Ag7 molecules of nonobese diabetic (NOD) mice, which results in weak agonistic activity of the peptide MHC complex. Here, we describe a strongly agonistic insulin mimetope that effectively converts naive T cells into Foxp3+ regulatory T cells in vivo, thereby completely preventing T1D in NOD mice. In contrast, natural insulin epitopes are ineffective. Subimmunogenic vaccination with strongly agonistic insulin mimetopes might represent a novel strategy to prevent T1D in humans at risk for the disease.
Exploring Scale Effects of Best/Worst Rank Ordered Choice Data to Estimate Benefits of Tourism in Alpine Grazing Commons
Authors: Scarpa Riccardo , Notaro Sandra , Louviere Jordan , Raffaelli Roberta
Published: June 2011

In many environmental valuation applications standard sample sizes for choice modelling surveys are impractical to achieve. One can improve data quality using more in‐depth surveys administered to fewer respondents. We report on a study using high quality rank‐ordered data elicited with the best‐worst approach. The resulting “exploded logit” choice model, estimated on 64 responses per person, was used to study the willingness to pay for external benefits by visitors for policies which maintain the cultural heritage of alpine grazing commons. We find evidence supporting this approach and reasonable estimates of mean WTP, which appear theoretically valid and policy informative.
Varying coefficient model for gene–environment interaction: a non-linear look
Authors: Ma Shujie , Yang Lijian , Romero Roberto , Cui Yuehua
Published: June 2011

Motivation: The genetic basis of complex traits often involves the function of multiple genetic factors, their interactions and the interaction between the genetic and environmental factors. Gene–environment (G×E) interaction is considered pivotal in determining trait variations and susceptibility of many genetic disorders such as neurodegenerative diseases or mental disorders. Regression-based methods assuming a linear relationship between a disease response and the genetic and environmental factors as well as their interaction is the commonly used approach in detecting G×E interaction. The linearity assumption, however, could be easily violated due to non-linear genetic penetrance which induces non-linear G×E interaction.

Results: In this work, we propose to relax the linear G×E assumption and allow for non-linear G×E interaction under a varying coefficient model framework. We propose to estimate the varying coefficients with regression spline technique. The model allows one to assess the non-linear penetrance of a genetic variant under different environmental stimuli, therefore help us to gain novel insights into the etiology of a complex disease. Several statistical tests are proposed for a complete dissection of G×E interaction. A wild bootstrap method is adopted to assess the statistical significance. Both simulation and real data analysis demonstrate the power and utility of the proposed method. Our method provides a powerful and testable framework for assessing non-linear G×E interaction.

Contact:  cui@stt.msu.edu

Supplementary information:  Supplementary data are available at Bioinformatics online.
False positive peaks in ChIP-seq and other sequencing-based functional assays caused by unannotated high copy number regions
Authors: Pickrell Joseph K. , Gaffney Daniel J. , Gilad Yoav , Pritchard Jonathan K.
Published: June 2011

Motivation: Sequencing-based assays such as ChIP-seq, DNase-seq and MNase-seq have become important tools for genome annotation. In these assays, short sequence reads enriched for loci of interest are mapped to a reference genome to determine their origin. Here, we consider whether false positive peak calls can be caused by particular type of error in the reference genome: multicopy sequences which have been incorrectly assembled and collapsed into a single copy.

Results: Using sequencing data from the 1000 Genomes Project, we systematically scanned the human genome for regions of high sequencing depth. These regions are highly enriched for erroneously inferred transcription factor binding sites, positions of nucleosomes and regions of open chromatin. We suggest a simple masking procedure to remove these regions and reduce false positive calls.

Availability: Files for masking out these regions are available at eqtl.uchicago.edu

Contact:  pickrell@uchicago.edu; dgaffney@uchicago.edu; gilad@uchicago.edu; pritch@uchicago.edu

Supplementary information:  Supplementary data are available at Bioinformatics online.
Telomere Erosion and Senescence in Human Articular Cartilage Chondrocytes
Authors: Martin James A. , Buckwalter Joseph A.
Published: June 2011

Aging and the degeneration of articular cartilage in osteoarthritis are distinct processes, but a strong association exists between age and the incidence and prevalence of osteoarthritis. We hypothesized that this association is due to in vivo replicative senescence, which causes age-related declines in the ability of chondrocytes to maintain articular cartilage. For this hypothesis to be tested, senescence-associated markers were measured in human articular chondrocytes from donors ranging in age from 1 to 87 years. These measures included in situ staining for senescence-associated β-galactosidase activity, 3H-thymidine incorporation assays for mitotic activity, and Southern blots for telomere length determinations. We found that senescence-associated β-galactosidase activity increased with age, whereas both mitotic activity and mean telomere length declined. These findings indicate that chondrocyte replicative senescence occurs in vivo and support the hypothesis that the association between osteoarthritis and aging is due in part to replicative senescence. The data also imply that transplantation procedures performed to restore damaged articular surfaces could be limited by the inability of older chondrocytes to form new cartilage after transplantation.
Morphological and Functional Characteristics of Skeletal Muscle Fibers From Hormone-replaced and Nonreplaced Postmenopausal Women
Authors: Widrick Jeffrey J. , Maddalozzo Gianni F. , Lewis Danielle , Valentine Beth A. , Garner Dena P. , Stelzer Julian E. , Shoepe Todd C. , Snow Christine M.
Published: June 2011

We tested the hypothesis that cross-bridge mechanisms of contraction differed in early postmenopausal women who did or did not receive hormone replacement therapy (HRT). Vastus lateralis biopsies were obtained from 17 postmenopausal women (49–57 years old), 8 of whom were on HRT for the previous 24 ± 5 months and 9 of whom were never on HRT. Electrophoresis and enzyme histochemistry revealed that fiber myosin heavy chain (MHC) isoform distribution, the cross-sectional area (CSA) of slow and fast fibers, and the relative CSA occupied by each, were similar for HRT and non-HRT groups. Single permeabilized fibers containing type IIa MHC had greater Ca2+-activated peak specific force, unloaded shortening velocity, and peak power than fibers containing type I MHC, but in all cases the values for HRT and non-HRT groups were similar. In this cross-sectional study, we found no evidence that Ca2+-activated fiber function, MHC isoform distribution, or relative CSA occupied by slow and fast fibers differed between HRT and non-HRT groups.
Skeletal Muscle Aging in F344BN F1-Hybrid Rats: I. Mitochondrial Dysfunction Contributes to the Age-Associated Reduction in VO2max
Authors: Hagen Jason L. , Krause Daniel J. , Baker David J. , Fu Ming Hua , Tarnopolsky Mark A. , Hepple Russell T.
Published: June 2011

Although mitochondrial DNA damage accumulates in aging skeletal muscles, how this relates to the decline in muscle mass-specific skeletal muscle aerobic function is unknown. We used a pump-perfused rat hind-limb model to examine maximal aerobic performance (V̇O2max) in young adult (YA; 8–9-month-old), late middle aged (LMA; 28–30-month-old) and senescent (SEN; 36-month-old) Fischer 344 × Brown Norway F1-hybrid rats at matched rates of convective O2 delivery (QO2). Despite similar muscle QO2 during a 4-minute contraction bout, muscle mass-specific V̇O2max was reduced in LMA (15%) and SEN (52%) versus YA. In plantaris muscle homogenates, nested polymerase chain reaction revealed an increased frequency of mitochondrial DNA deletions in the older animals. A greater reduction in the flux through electron transport chain complexes I–III than citrate synthase activity in the older animals suggests mitochondrial dysfunction consequent to mitochondrial DNA damage with aging. These results support the hypothesis that a reduced oxidative capacity, due in part to age-related mitochondrial dysfunction, contributes to the decline in aerobic performance in aging skeletal muscles.
Skeletal Muscle Aging in F344BN F1-Hybrid Rats: II. Improved Contractile Economy in Senescence Helps Compensate for Reduced ATP-Generating Capacity
Authors: Hepple Russell T. , Hagen Jason L. , Krause Daniel J. , Baker David J.
Published: June 2011

We used a pump-perfused rat hind-limb preparation to compare young adult (YA: 8–9- month-old), late middle-aged (LMA: 28–29-month-old), and senescent (SEN: 36-month-old) rats at similar rates of convective O2 delivery during a 4-minute contraction bout. We hypothesized that not only would V̇O2 and lactate production be reduced, but also that contractile economy would be altered with aging. Peak tension was lower in LMA (42%) and SEN (71%) versus YA. V̇O2 and lactate efflux was progressively lower with increasing age. Estimated adenosine triphosphate per N of force was increased in LMA (35%) and reduced in SEN (31%) versus YA. Myosin heavy chain (MHC) analysis by sodium dodecyl sulphate–polyacrylamide gel electrophoresis showed a lower MHC type IIb and higher MHC type IIa/IIx in SEN versus YA. Therefore, whereas contractile economy is impaired in LMA, it is improved in SEN, and this latter effect may be due in part to reduced type IIb MHC.
Trends in Hearing Impairment in United States Adults: The National Health Interview Survey, 1986–1995
Authors: Lee David J. , Gómez-Marín Orlando , Lam Byron L. , Zheng D. Diane
Published: June 2011

Background. United States trends in the prevalence of hearing impairment have not been reported. These trends could be rising due to changes in environmental noise exposure; alternatively, rates could be declining via a compression of morbidity hypothesis that has been postulated to be occurring in older adults residing in developed nations.

Methods. The National Health Interview Survey is a continuous multistage area probability survey of the U.S. civilian noninstitutionalized population living at addressed dwellings. Adults within randomly selected households were administered a chronic conditions list that included questions about hearing impairment. Complete data were available on 107,100 white and 17,904 African-American adults aged 18 years and older in survey years 1986–1995. Race-specific rates of hearing impairment were adjusted for age and sample survey design.

Results. Annual age-adjusted rates of some hearing impairment ranged from 11.0% to 12.7% in whites and 5.9% to 8.5% in African Americans. Rates of severe bilateral hearing impairment in these race groups were 0.7% to 1.1% and 0.1% to 0.5%, respectively. There was no evidence of change in rates of hearing impairment among participants stratified by race and 10-year age groups.

Conclusions. Reported rates of hearing impairment remained relatively stable in the U.S. noninstitutionalized population from 1986 to 1995. There was no evidence of change in rates in adults grouped into 10-year age groups. Population-based studies designed to include clinical and self-reported measures of hearing impairment are needed to further examine trends in hearing impairment.
Case-Finding for Depression in Elderly People: Balancing Ease of Administration With Validity in Varied Treatment Settings
Authors: Blank Karen , Gruman Cynthia , Robison Julie T.
Published: June 2011

Background. Little is known about the performance of brief and ultrabrief (1- and 2-question) depression screens in older patients across varied treatment sites. This study (1) assesses their validity in clinics, hospitals, and nursing homes and (2) assesses cut-points for optimal clinical application.

Methods. 360 patients aged 60 years and older from 2 urban primary care practices (n = 125), 1 general hospital (n = 150), and 8 nursing homes (n = 85) were assessed using the Yale 1-question screen, the 2-question instrument derived from the Primary Care Evaluation of Mental Disorders, and long and short versions of the Center for Epidemiologic Studies Depression (CES-D) scale and Geriatric Depression Scale (GDS). Sensitivity and specificity were calculated for each screen compared with the criterion standard Diagnostic Interview Schedule (DIS) depression diagnosis and receiver operating characteristic curves generated.

Results. 9% of patients met DIS criteria for major depression and 7% for subsyndromal depression. Overall, the 10-item CES-D showed the best sensitivity/specificity for major depression in clinics (79%/81%) and hospitals (92%/77%), and the short GDS in nursing homes (86%/82%). Specificity of 1- and 2-question instruments was generally low. Established cut-points generally worked best for the short screens, while modifications were useful for longer versions.

Conclusions. Consideration of site of use is important in selecting brief case-finding instruments for late-life depression, with the 10-item CES-D working best in medical settings and the 15-item GDS in nursing homes.
Dietary Variety Predicts Low Body Mass Indexand Inadequate Macronutrient and MicronutrientIntakes in Community-Dwelling Older Adults
Authors: Roberts Susan B. , Hajduk Cheryl L. , Howarth Nancy C. , Russell Robert , McCrory Megan A.
Published: June 2011

Background. Low body mass index (BMI) and micronutrient deficiencies are associated with increased morbidity and mortality rates in old age. Whether adverse patterns of dietary variety predict both low BMI and low micronutrient intakes in older adults was investigated.

Methods. A cross-sectional analysis of national survey data was conducted in 1174 healthy adult men and women (ages 21 to 90 years) who provided physiologically plausible dietary data in the 1994–1996 Continuing Survey of Food Intakes by Individuals. Measurements included reported energy intake, protein intake (percentage meeting Recommended Dietary Allowance), micronutrient intakes (percentage meeting Estimated Average Requirements for 14 micronutrients), and BMI.

Results. Adults who were 61 years or older consumed a greater total variety of foods, chose foods from a wider range of food groups, had a greater variety of micronutrient-dense foods and energy-weak foods, and had a lower variety of micronutrient-weak foods compared with adults ages 21 to 60 years (p <.05 to.001). However, older adults with low BMIs (<22 kg/m2) consumed a lower variety of energy-dense foods compared with older adults with higher BMIs (p <.05). The variety of energy-dense foods predicted both energy intake and BMI at all ages in multiple regression models controlling for confounding variables (R2 =.124 for energy, R2 =.574 for BMI, p <.001). A higher percentage of older persons had inadequate micronutrient intakes compared with younger persons (p <.05), especially vitamin E, calcium, and magnesium, but consumption of a particularly wide variety of micronutrient-rich foods helped counterbalance these trends (p <.05). Older adults who had a low BMI and consumed a low variety of micronutrient-dense foods were particularly at nutritional risk, with only 65.4% consuming the Recommended Dietary Allowance for protein and none meeting the Estimated Average Requirements for all 14 micronutrients.

Conclusions. In contrast to previous suggestions that older persons consume a monotonous diet, this study showed that adults who were 61 years or older consumed a greater total food variety, and a greater variety of micronutrient-dense and energy-weak foods, compared with adults who were 60 years or younger. Although consumption of a low variety of energy-dense foods may contribute to reduced energy intake and body weight at any age, the variety of micronutrient-dense foods consumed needs to increase in old age to prevent micronutrient deficiencies. These findings suggest that all adults need advice on the changing needs for dietary variety with aging to maintain health, and that older persons with low BMI are particularly vulnerable to dietary shortfalls.
Intergenerational Triads in Grandparent-Headed Families
Authors: Goodman Catherine Chase
Published: June 2011

Objectives. Grandparents are becoming caregivers of their grandchildren more often as a result of their adult children's drug addiction, mental problems, and financial need. This study examined grandmothers' well-being in relation to bonding within intergenerational triads consisting of grandmother, parent, and grandchild.

Methods. Interviews were conducted with 987 grandmothers recruited through schools and media, including 512 custodial grandmothers raising their grandchildren and 475 coparenting grandmothers helping their adult sons or daughters to raise their grandchildren.

Results. Contrary to expectation, triangulation involving a weak parent–grandmother relationship was not related to significantly lower grandmother well-being. In contrast, the emotionally isolated parent, particularly common in custodial families, was related to lower grandmother well-being, whether or not the parent lived in the household. The configuration in which the parent provided a link for both other generations was frequent in coparenting families, but it was not significantly different in grandmother well-being compared to other linking triads.

Discussion. Intergenerational triad types appear to be broadly relevant emotional configurations that transcend living situations but appear with different frequencies in custodial and coparenting families. Results affirm the utility of examining multirelationship patterns and describe the restructuring of intergenerational relationships characteristic of parental absence.
Life on the Edge: Patterns of Formal and Informal Help to Older Adults in the United States and Sweden
Authors: Davey Adam , Femia Elia E. , Zarit Steven H. , Shea Dennis G. , Sundström Gerdt , Berg Stig , Smyer Michael A. , Savla Jyoti
Published: June 2011

Objectives. Our objective in this study was to compare assistance received by individuals in the United States and Sweden with characteristics associated with low, moderate, or high 1-year placement risk in the United States.

Methods . We used longitudinal nationally representative data from 4,579 participants aged 75 years and older in the 1992 and 1993 waves of the Medicare Current Beneficiary Survey (MCBS) and cross-sectional data from 1,379 individuals aged 75 years and older in the Swedish Aging at Home (AH) national survey for comparative purposes. We developed a logistic regression equation using U.S. data to identify individuals with 3 levels (low, moderate, or high) of predicted 1-year institutional placement risk. Groups with the same characteristics were identified in the Swedish sample and compared on formal and informal assistance received.

Results . Formal service utilization was higher in Swedish sample, whereas informal service use is lower overall. Individuals with characteristics associated with high placement risk received more formal and less informal assistance in Sweden relative to the United States.

Discussion . Differences suggest formal services supplement informal support in the United States and that formal and informal services are complementary in Sweden.
Social Environments and the Genetics of Aging: Advancing Knowledge of Protective Health Mechanisms
Authors: Ryff Carol D. , Singer Burton H.
Published: June 2011

We selectively review the literature in behavioral and molecular genetics, including both laboratory and epidemiologic studies, with emphasis on how social environments, particularly emotion in significant social relationships, influence gene expression. Attention is given to cross-talk between human and animal studies. Environments are pivotal in understanding phenotypic outcomes, and this demands research on gene–environment interactions. Illustrative interactions, involving both behavioral and molecular genetics, are provided. Many people with susceptibility genes for diverse diseases never proceed to disease status. Substantial associational evidence implicates social environmental factors as protective agents. Mechanistic understanding of these linkages is quite advanced in some animal populations and suggests new lines of inquiry in human studies. Developing the interface between genetics, social environments, and health will require close collaboration between those well versed in molecular biology and biochemistry and persons with expertise in genetic epidemiology and social psychology. Particularly important is the identification of environmental influences that protect susceptible persons from disease incidence.
The Inherent Complexities of Gene–Environment Interactions
Authors: Grigorenko Elena L.
Published: June 2011

The article outlines the complexities of gene–environment interactions in the determination of human disease, especially as they relate to aging, and stresses the importance of continuing such studies, in spite of their inherent difficulties. First, a capsule review of the literature pertaining to studies of gene–environment interactions is presented, and designs and methodologies used to detect these interactions are briefly discussed. Second, research questions and problems that can be addressed as outcomes of gene–environment interaction studies are exemplified. Third, a number of illustrative examples of gene–environment interactions are presented. Fourth, various types of gene–environment interactions are briefly discussed. Fifth, concluding remarks are offered, and possibilities of studying gene–environment interaction within social and biological research on aging are outlined.
Marital Quality, Health, and Aging: Gender Equity?
Authors: Umberson Debra , Williams Kristi
Published: June 2011

Recent research shows that poor marital quality adversely affects trajectories of physical health over time and that these adverse effects are similar for men and women. These studies test the possibility of gender differences in vulnerability to poor marital quality, but they fail to take into account possible gender differences in exposure to poor marital quality. We present longitudinal evidence to show that although the impact of marital quality on physical health trajectories may be similar for married men and women, generally lower levels of marital quality experienced by women may translate into a sustained disadvantage for the health of married women over the life course. These findings frame the call for renewed theoretical work on gender and marriage that takes into account both gender similarity in response to marital quality as well as gender differences in the experience of marriage over the life course.
Family Structure, Gender, and Health in the Context of the Life Course
Authors: Avison William R. , Davies Lorraine
Published: June 2011

We estimate the effects of single parenthood on parental health and determine whether such effects are similar for all single parents or whether there are variations by gender among young, middle-aged, and older adults. The results of our analyses of the Canadian National Population Health Survey (NPHS) reveal that single parenthood is associated with elevated psychological distress and alcohol consumption among women, especially among those who are in younger age groups. Although we find no such differences among men, there is some indication of elevated distress among younger fathers. We discuss the implications of these findings for thinking about single parenthood at various life stages.
Processes of Cumulative Adversity: Childhood Disadvantage and Increased Risk of Heart Attack Across the Life Course
Authors: O'Rand Angela M. , Hamil-Luker Jenifer
Published: June 2011

Objectives. This article examines how processes of cumulative adversity shape heart attack risk trajectories across the life course.

Methods. Our sample includes 9760 Health and Retirement Study respondents born between 1931 and 1941. Using self-reported retrospective measures of respondents' early background, we first identify three latent classes with differential exposure to childhood disadvantage. Intervening covariates associated with educational attainment, employment status, income attainment, marital history, and health behaviors are added to capture sequential processes of adversity. Final latent-class cluster models estimate the cumulative impact of these covariates on three different heart attack risk trajectories between 1992 and 2002: high, increasing, and low.

Results. Early disadvantage and childhood illness have severe enduring effects and increase the risk for heart attack. Adult pathways, however, differentially influence trajectories of heart attack risk and mediate the effects of early disadvantage.

Discussion. Findings suggest that future research should consider how processes of cumulative adversity initiated in childhood influence health outcomes in older ages.
Early Adversity and Later Health: The Intergenerational Transmission of Adversity Through Mental Disorder and Physical Illness
Authors: Wickrama K. A. S. , Conger Rand D. , Abraham W. Todd
Published: June 2011

Objectives. The authors' objective was to investigate processes that account for the transmission of socioeconomic adversity from one generation to the next through mental disorder and physical illness.

Methods. The present longitudinal study of 485 youth used structural equation models to test an intergenerational model proposing that: (a) stressful childhood experiences in the family of origin contribute to the development of mental disorder and physical illness during adolescence both directly and indirectly through disruption in an adolescent's transition to young adulthood; (b) during the transition to adulthood, mental disorders and physical illnesses increase in part through reciprocal influence; and (c) both the levels of and changes in mental disorder and physical illness are independently associated with adverse life circumstances during early adulthood.

Results. Findings generally supported the hypothesized model. Family of origin adversity contributed to the impaired mental and physical health of adolescents. This influence was largely mediated through adolescents' disrupted transition to young adulthood. Levels of both mental and physical illnesses independently contributed to young adult adversity. Levels of physical health problems influenced changes in mental disorders. Changes in both mental and physical illnesses are also associated with young adult adversity.

Discussion. The study demonstrates key mediating pathways in the intergenerational transmission of social adversity and also highlights the importance of improving both socioeconomic and health resources for adolescents.
Conceptualizing and Identifying Cumulative Adversity and Protective Resources: Implications for Understanding Health Inequalities
Authors: Hatch Stephani L.
Published: June 2011

This article focuses on cumulative adversity and protective resources, both social and biological, that interrupt or deflect individuals from optimal life-course trajectories and contribute to widening gaps in health. Under the guiding framework of cumulative adversity and/or advantage, this narrative discusses the theoretical framework of cumulative adversity, presents identified sources of cumulative adversity and protective resources, and highlights the utilization of the life-course approach. Numerous social and biological adverse conditions are identified across multiple domains. Utilizing the life-course perspective in identifying early life determinants and the paucity of information regarding identified protective factors are discussed. Understanding health inequalities requires attention paid to heterogeneity in the impact of social statuses as well as sources of cumulative adversity and protective resources within diverging trajectories across the life course. Intervention implications are discussed, and suggestions for future research are made.
Continuity and Change in the Social Stratification of Aging and Health Over the Life Course: Evidence From a Nationally Representative Longitudinal Study From 1986 to 2001/2002 (Americans' Changing Lives Study)
Authors: House James S. , Lantz Paula M. , Herd Pamela
Published: June 2011

Objectives. This article overviews previously published and ongoing research from the Americans' Changing Lives (ACL) Study, a longitudinal study of a nationally representative sample of 3,617 adults aged 25 years and older when first interviewed in 1986, focusing on socioeconomic disparities in the way health changes with age during middle and later life, especially in terms of compression of morbidity/functional limitations.

Methods. A variety of descriptive and multivariate regression and growth curve analyses are done on the ACL sample, now surveyed over four waves spanning 15.5 years between 1986 and 2001/2002 with continuing mortality ascertainment via the National Death Index, death certificate searches, and informant reports.

Results. Both cross-sectional and longitudinal analyses indicate that socioeconomic disparities in health are small in early adulthood, increase through middle and early old age, and then lessen again in later old age. In other terms, compression of morbidity/functional limitations into the later stages of the life course is realized to a much greater degree among the better educated compared with the less educated. Cross-sectional evidence suggests that this reflects differential exposure to or experience of a wide range of psychosocial, environmental, and biomedical risk factors for health (and perhaps their differential impact at different ages and life stages), as well as variations in biological robustness and frailty and also perhaps in the strength of social welfare supports for health at different life stages. Longitudinal analyses reveal several new insights: (a) The flow of causality is much greater from socioeconomic position to health than vice versa; (b) education plays a greater role relative to income in the onset of functional limitations, whereas income has much stronger effects on their progression or course; and (c) educational disparities in the onset and hence of compression of functional limitations over the life course have increased strikingly in later middle and early old age (ages 55–84 years) since 1986.

Discussion. The results indicate that understanding and alleviating social disparities in health are both theoretically and methodologically quintessential problems of life course analysis and research.
Do Daily Stress Processes Account for Socioeconomic Health Disparities?
Authors: Almeida David M. , Neupert Shevaun D. , Banks Sean R. , Serido Joyce
Published: June 2011

Objectives. The present study examined the extent to which daily stressor severity and appraisals of the stressors accounted for socioeconomic disparities in health.

Methods. Data from the National Study of Daily Experiences and the Midlife in the United States Survey were combined for the current analyses, resulting in 1,031 respondents who reported on 7,229 days.

Results. Respondents without a high school degree experienced more severe stressors and appraised stressors as posing greater risk to their financial situation and to their self-concept than respondents with a high school or college degree. Differences in severity and stressor appraisal accounted for education differences in psychological distress and physical health symptoms.

Discussion. Findings suggest the importance of considering variation across stressors, particularly implications for self-concept, in understanding sources of differential stressor vulnerability.
Aging, Migration, and Mortality: Current Status of Research on the Hispanic Paradox
Authors: Markides Kyriakos S. , Eschbach Karl
Published: June 2011

Objective. We reviewed recent evidence on the apparent Hispanic mortality paradox.

Methods. Recent studies using vital statistics, national community surveys linked to the National Death Index, Medicare data linked to application records for social security cards maintained in the Social Security Administration NUDIMENT file, and mortality follow-up by regional studies are reviewed critically.

Results. Data based on vital statistics show the greatest mortality advantage compared with non-Hispanic Whites for all Hispanics combined. The advantage is greatest among older people. National Community Surveys linked to the National Death Index show a narrowing of the advantage, and one study suggests that the Mexican Origin mortality advantage can be attributed to selective return migration of less healthy immigrants to Mexico. The Medicare–NUDIMENT data that avoid problems of other data sets also show an advantage in mortality among Hispanic elders, although the advantage is considerably lower than is found using the vital statistics method.

Discussion. Although some research has recently begun to question whether indeed all Hispanic groups enjoy a mortality advantage, the majority of the evidence continues to support a mortality advantage at a minimum among Mexican Americans and especially in old age, at least among men, which may provide partial, albeit indirect, support for a selective return migration or “salmon bias” effect. There is a need to further explore the existence of a selective return migration effect with expanded data bases that include more subjects from the various Hispanic origins. To date, the majority of the evidence continues to support the Hispanic paradox at least among people of Mexican origin and calls for additional attention to this interesting and highly important phenomenon.
Gender Disparities in Health: Strategic Selection, Careers, and Cycles of Control
Authors: Moen Phyllis , Chermack Kelly
Published: June 2011

This article proposes a dynamic model of the intersections between gender, health, and the life course incorporating processes of strategic selection—of roles, relationships, and behavior. Men and women make decisions within a tangled web of multilayered, often contradictory, and frequently outdated institutional contexts of opportunity and constraint. Both their decisions and the institutions shaping them reflect prior as well as ongoing socialization and allocation mechanisms. These institutionalized scripts and regimes tend to reproduce gendered biographical paths around two central life foci: paid work (or careers) and unpaid family work (or careers). The gendered nature of occupational and family-care paths, in turn, produces patterned disparities in a constellation of health-related resources, relationships, and risks, as well as feelings of mastery and control. We call for research charting alternative constellations of these gendered health careers, their antecedents, temporal patterning, and consequences.
Medicago truncatula IPD3 Is a Member of the Common Symbiotic Signaling Pathway Required for Rhizobial and Mycorrhizal Symbioses
Authors: Horváth Beatrix , Yeun Li Huey , Domonkos Ágota , Halász Gábor , Gobbato Enrico , Ayaydin Ferhan , Miró Krisztina , Hirsch Sibylle , Sun Jongho , Tadege Million , Ratet Pascal , Mysore Kirankumar S. , Ané Jean-Michel , Oldroyd Giles E. D. , Kaló Péter
Published: June 2011

Legumes form endosymbiotic associations with nitrogen-fixing bacteria and arbuscular mycorrhizal (AM) fungi which facilitate nutrient uptake. Both symbiotic interactions require a molecular signal exchange between the plant and the symbiont, and this involves a conserved symbiosis (Sym) signaling pathway. In order to identify plant genes required for intracellular accommodation of nitrogen-fixing bacteria and AM fungi, we characterized Medicago truncatula symbiotic mutants defective for rhizobial infection of nodule cells and colonization of root cells by AM hyphae. Here, we describe mutants impaired in the interacting protein of DMI3 (IPD3) gene, which has been identified earlier as an interacting partner of the calcium/calmodulin-dependent protein, a member of the Sym pathway. The ipd3 mutants are impaired in both rhizobial and mycorrhizal colonization and we show that IPD3 is necessary for appropriate Nod-factor-induced gene expression. This indicates that IPD3 is a member of the common Sym pathway. We observed differences in the severity of ipd3 mutants that appear to be the result of the genetic background. This supports the hypothesis that IPD3 function is partially redundant and, thus, additional genetic components must exist that have analogous functions to IPD3. This explains why mutations in an essential component of the Sym pathway have defects at late stages of the symbiotic interactions.
Enhanced Viral Intergenic Region–Specific Short Interfering RNA Accumulation and DNA Methylation Correlates with Resistance Against a Geminivirus
Authors: Yadav Rajiv Kumar , Chattopadhyay Debasis
Published: June 2011

RNA silencing mediated by short-interfering RNA (siRNA) is used by plants as a defense against viruses. In the case of geminiviruses, viral DNA is targeted at the transcriptional level, while virus-derived transcripts are targeted by posttranscriptional silencing. Mungbean yellow mosaic India virus (MYMIV), a bipartite geminivirus, causes yellow mosaic disease in soybean (Glycine max). A soybean variety resistant to this disease has been identified (line PK416). To understand the molecular mechanism underlying this resistance, distribution of MYMIV-derived siRNAs along the viral genome was compared in resistant and susceptible plants, using samples obtained in the first few days following inoculation. We observed that, in the resistant soybean variety, most of the virus-derived siRNAs were complementary to the intergenic region (IR), while in the susceptible variety (line JS335), a majority of the siRNAs corresponded to coding regions of the viral genome. Most of the IR-specific siRNA molecules produced in the resistant plants were 24 nt in size. Bisulfite sequencing showed that, in the resistant plants, a higher level of methylation occurred in the IR of viral DNA.
Predicting Soybean Rust Incursions into the North American Continental Interior Using Crop Monitoring, Spore Trapping, and Aerobiological Modeling
Authors: Isard S. A. , Barnes C. W. , Hambleton S. , Ariatti A. , Russo J. M. , Tenuta A. , Gay D. A. , Szabo L. J.
Published: June 2011

Between 2005 and 2009, millions of U.S. and Canadian soybean acres that would have received fungicide application remained untreated for soybean rust due to information disseminated through the Integrated Pest Management Pest Information Platform for Extension and Education (ipmPIPE), increasing North American producers' profits by hundreds of millions of dollars each year. The results of our analysis of Phakopsora pachyrhizi urediniospores in rain collections, aerobiology model output, and observations of soybean rust spread in 2007 and 2008 show a strong correspondence between spore collections and model predictions for the continental interior of North America, where soybean is an important crop. The analysis suggests that control practices based on up-to-date maps of soybean rust observations and associated commentary from Extension Specialists delivered by the ipmPIPE may have suppressed the number and strength of inoculum source areas in the southern states and retarded the northward progress of seasonal soybean rust incursions into continental North America. The analysis further indicates that spore trapping and aerobiological modeling can reduce our reliance on the costly Sentinel Plot Network while maintaining the effectiveness of the ipmPIPE system for soybean rust management.
Sensitivity of Isolates of Phytophthora capsici from the Eastern United States to Fluopicolide
Authors: Keinath Anthony P. , Kousik Chandrasekar S.
Published: June 2011

Fluopicolide, a pyridinylmethyl-benzamide fungicide, was registered in the United States in 2008 to control diseases caused by Oomycete pathogens, such as Phytophthora capsici, on cucurbit and solanaceous vegetables. The main objective of this study was to determine baseline sensitivity to fluopicolide in isolates of P. capsici from the southeastern and midwestern United States. A total of 69 isolates from Florida (14 isolates), Georgia (14 isolates), Michigan (24 isolates), North Carolina (3 isolates), and South Carolina (17 isolates) that had not been previously exposed to fluopicolide were grown on fungicide-amended medium to determine sensitivity of mycelia, sporangia, and zoospores to the fungicide. All isolates of P. capsici tested (range of 54 to 69 isolates per assay) were sensitive to fluopicolide in all four assays. The median EC50 fluopicolide concentration was 0.22, 2.08, 0.048, and 0.10 mg/liter in the mycelial growth, zoospore germination, sporangia production, and zoospore production assays, respectively. For mycelial growth and zoospore germination, isolates from Michigan had a higher mean EC50 value than isolates from the four southeastern states. This is the first report of variation in baseline sensitivity to a fungicide by P. capsici isolates from different regions of the United States. In the sporangia production and zoospore production assays, isolates from different states did not differ in sensitivity. Single rates of fluopicolide were tested with additional isolates to validate discriminatory rates for monitoring sensitivity. A concentration of 0.3 or 1.0 mg/liter is recommended for mycelial growth, and 0.1 mg/liter is recommended for sporangia and zoospore production.
First Report of Sida micrantha mosaic virus in Phaseolus vulgaris in Brazil
Authors: Fernandes-Acioli N. A. N. , Pereira-Carvalho R. C. , Fontenele R. S. , Lacorte C. , Ribeiro S. G. , Fonseca M. E. N. , Boiteux L. S.
Published: June 2011

Snap and common beans (Phaseolus vulgaris L.) are severely affected by Bean golden mosaic virus (BGMV) infection, so far the only begomovirus reported on these crops in Brazil (1). Samples of snap and common beans colonized by the whitefly Bemisia tabaci biotype B and displaying golden mosaic, chlorotic spots, and leaf distortion were collected in three production regions in Goiás State (Goianápolis, Luziânia, and Itaberaí) between 2003 and 2007. Total DNA extracted from leaf samples was used as template in PCR assays using universal primers targeting conserved regions of the DNA-A and DNA-B genomes (3). Begomovirus-specific amplicons were observed only with DNA template from symptomatic plants. Two single amplicons were observed for both genomic segments, indicating the presence of bipartite species in all samples. Sequence analysis of four isolates (named as GO-176, GO-260, GO-354, and GO-368) obtained from common bean samples indicated identity levels of approximately 95% with the DNA-A segment of BGMV (GenBank Accession No. FJ665283). However, the complete DNA-A sequence (GenBank Accession No. HM357459.1) of the GO-060 isolate (from a symptomatic snap bean plant collected in Goianápolis) displayed 76% identity with BGMV (GenBank Accession No. FJ665283) and 95% identity with the DNA-A of a Sida micrantha mosaic virus (SimMV) isolate (GenBank Accession No. EU908733.1) reported to be infecting okra (Abelmoschus esculentus L.) and 94.8% with a SimMV isolate reported to be infecting soybean (GenBank Accession No. FJ686693) in Brazil (2). Koch's postulates were fulfilled for the isolate GO-060 by inoculating a set of soybean and bean accessions via a biolistic approach. The ratio of positive PCR amplicons per total of inoculated plants were 15 of 16 for snap bean cv. Trepador, 9 of 10 for snap bean cv. Fartura, 18 of 24 for common bean cv. Olate Pinto, and 19 of 25 for common bean cv. Carioca. The isolate was also able to infect eight of nine soybean ‘Doko’ plants. Sequence analysis using symptomatic leaf samples (15 days after inoculation) confirmed SimMV as the causal agent. To our knowledge, this is the first report of a SimMV isolate infecting P. vulgaris. This virus is apparently fast expanding its host range from Malvaceae to Solanaceae species and leguminous hosts after the introduction of B. tabaci biotype B (2). More extensive surveys are necessary to access the current epidemiological importance of SimMV in both snap and common beans in Brazil.

References: (1) J.C. Faria and D. P. Maxwell. Phytopathology 89:262, 1999. (2) F. R. Fernandes et al. Arch. Virol. 154:1567, 2009. (3) M. R. Rojas et al. Plant Dis. 77:340, 1993.
Distribution of Potato virus Y in Potato Plant Organs, Tissues, and Cells
Authors: Kogovšek P. , Kladnik A. , Mlakar J. , Žnidarič M. Tušek , Dermastia M. , Ravnikar M. , Pompe-Novak M.
Published: June 2011

The distribution of Potato virus Y (PVY) in the systemically infected potato (Solanum tuberosum) plants of the highly susceptible cultivar Igor was investigated. Virus presence and accumulation was analyzed in different plant organs and tissues using real-time polymerase chain reaction and transmission electron microscopy (TEM) negative staining methods. To get a complete insight into the location of viral RNA within the tissue, in situ hybridization was developed and optimized for the detection of PVY RNA at the cellular level. PVY was shown to accumulate in all studied leaf and stem tissues, in shoot tips, roots, and tubers; however, the level of virus accumulation was specific for each organ or tissue. The highest amounts of viral RNA and viral particles were found in symptomatic leaves and stem. By observing cell ultrastructure with TEM, viral cytoplasmic inclusion bodies were localized in close vicinity to the epidermis and in trichomes. Our results show that viral RNA, viral particles, and cytoplasmic inclusion bodies colocalize within the same type of cells or in close vicinity.