Organisms are exposed to strong selective pressures from several sources, including predators and pathogens. Response to such interacting selective pressures may vary among species that differ in life history and ecology in predictable ways. We consider the impact of multiple enemies (fish predators and trematode parasites) on the behavior of larvae of three anuran species (Lithobates ( = Rana) sylvaticus, L. clamitans and L. catesbeianus). We show that the three ranid species differ in response to the trade-off imposed by the simultaneous presence of fish predators and trematode parasites in the environment. Two more permanent pond breeders (L. clamitans and L. catesbeianus), which commonly encounter parasites and fish, increased activity when in the combined presence of parasites and a fish predator, resulting in a relatively lower parasite encystment rate. In contrast, the temporary pond breeder (L. sylvaticus), which does not commonly encounter fish in the wild, decreased activity in the combined presence of a fish predator and parasites similar to when only the predator was present. For L. sylvaticus, this suggests that the presence of an unknown predator poses a greater threat than parasites. Further, the presence of fish along with parasites increased the susceptibility of both L. sylvaticus and L. clamitans to trematode infection, whereas parasite infection in L. catesbeianus was unaffected by the presence of fish. Unpalatability to fish may allow some species to respond more freely to attacking parasites in the presence of fish. The results from this study highlight the importance of considering multiple selective pressures faced by organisms and how this shapes their behavior.
The emergence of amphibian chytridiomycosis, caused by the fungus Batrachochytrium dendrobatidis (Bd) has led to the decline and extinction of numerous amphibian species. Multiple studies have observed links between climatic factors and amphibian declines apparently caused by Bd. Using outdoor experimental mesocosms, we tested the response of red-legged frog (Rana aurora) tadpoles to increased variation in temperature, a component of climate linked to amphibian declines, and Bd exposure. We included tadpoles of a sympatric competitor species, Pacific chorus frog (Pseudacris regilla), in a fully factorial design to test the effects of Bd and temperature on interspecific interactions. We found that higher variation in temperature had numerous effects in mesocosms, including interacting with Bd presence to decrease the condition of R. aurora, shifting the relative performance of competing P. regilla and R. aurora, and accelerating the development of P. regilla relative to R. aurora. Our results demonstrate that increased variation in temperature can affect amphibians in multiple ways that will be contingent on ecological context, including the presence of Bd and competing species.
Chytridiomycosis; climate change; competition; mesocosm; tadpole; temperature
Injection drug users (IDUs) are at risk for HIV and other bloodborne pathogens through receptive syringe sharing (RSS) and receptive paraphernalia sharing (RPS). Research into the influence of the perceived risk of HIV infection on injection risk behavior has yielded mixed findings. One explanation may be that consequences other than HIV infection are considered when IDUs are faced with decisions about whether or not to share equipment. We investigated the perceived consequences of refusing to share injection equipment among 187 IDUs recruited from a large syringe exchange program in Los Angeles, California, assessed their influence on RSS and RPS, and evaluated gender differences. Two sub-scales of perceived consequences were identified: structural/external consequences and social/internal consequences. In multiple linear regression, the perceived social/internal consequences of refusing to share were associated with both RSS and RPS, after controlling for other psychosocial constructs and demographic variables. Few statistically significant gender differences emerged. Assessing the consequences of refusing to share injection equipment may help explain persistent injection risk behavior, and may provide promising targets for comprehensive intervention efforts designed to address both individual and structural risk factors.
Injection drug use; HIV; gender; perceived consequences; syringe sharing
Use of neuropsychological tests to identify HIV-associated neurocognitive dysfunction must involve normative standards that are well-suited to the population of interest. Norms should be based on a population of HIV-uninfected individuals as closely matched to the HIV-infected group as possible, and must include examination of the potential effects of demographic factors on test performance. This is the first study to determine the normal range of scores on measures of psychomotor speed and executive function among a large group of ethnically and educationally diverse HIV-uninfected, high risk women, as well as their HIV-infected counterparts. Participants (n = 1653) were administered the Trailmaking Test Parts A and B (Trails A and Trails B), the Symbol Digit Modalities Test (SDMT), and the Wide Range Achievement Test-3 (WRAT-3). Among HIV-uninfected women, race/ethnicity accounted for almost 5% of the variance in cognitive test performance. The proportion of variance in cognitive test performance accounted for by age (13.8%), years of school (4.1%) and WRAT-3 score (11.5%) were each significant, but did not completely account for the effect of race (3%). HIV-infected women obtained lower scores than HIV-uninfected women on time to complete Trails A and B, SDMT total correct, and SDMT incidental recall score, but after adjustment for age, years of education, racial/ethnic classification, and reading level, only the difference on SDMT total correct remained significant. Results highlight the need to adjust for demographic variables when diagnosing cognitive impairment in HIV-infected women. Advantages of demographically adjusted regression equations developed using data from HIV-uninfected women are discussed.
Injection drug users (IDUs) are at risk for HIV and other bloodborne pathogens via syringe and paraphernalia sharing, and women are at elevated risk. Consequences of injection risk behavior such as the risk of becoming infected with HIV have been relatively well studied, though less is known about the consequences of refusing to share injection equipment. We conducted in-depth qualitative interviews with 26 IDUs recruited from a syringe exchange program in Los Angeles, California, USA to understand the consequences that IDUs associate with refusing to share injection equipment and to determine whether these perceived consequences differ by gender. Perceived consequences were organized into four domains using a Social Ecological framework: microsystem (perceived risk of HIV, drug withdrawal or forgoing drug use), exosystem (trust and social norms), mesosystem (precarious housing and shelter policies), and macrosystem (syringe access/inconvenience, economic and legal consequences). Gender differences were identified in some, but not all areas. Effective public health interventions among IDUs will benefit from a holistic perspective that considers the environmental and social rationality (Kowalewski et al., 1997) of decisions regarding injection risk behavior, and assists individuals in addressing the consequences that they perceive to be most salient.
HIV; injection drug use; gender; qualitative methods; perceived consequences; behavioral theory
The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) Central Repository makes data and biospecimens from NIDDK-funded research available to the broader scientific community. It thereby facilitates: the testing of new hypotheses without new data or biospecimen collection; pooling data across several studies to increase statistical power; and informative genetic analyses using the Repository’s well-curated phenotypic data. This article describes the initial database plan for the Repository and its revision using a simpler model. Among the lessons learned were the trade-offs between the complexity of a database design and the costs in time and money of implementation; the importance of integrating consent documents into the basic design; the crucial need for linkage files that associate biospecimen IDs with the masked subject IDs used in deposited data sets; and the importance of standardized procedures to test the integrity data sets prior to distribution. The Repository is currently tracking 111 ongoing NIDDK-funded studies many of which include genotype data, and it houses over 5 million biospecimens of more than 25 types including serum, plasma, stool, urine, DNA, red blood cells, buffy coat and tissue. Repository resources have supported a range of biochemical, clinical, statistical and genetic research (188 external requests for clinical data and 31 for biospecimens have been approved or are pending). Genetic research has included GWAS, validation studies, development of methods to improve statistical power of GWAS and testing of new statistical methods for genetic research. We anticipate that the future impact of the Repository’s resources on biomedical research will be enhanced by (i) cross-listing of Repository biospecimens in additional searchable databases and biobank catalogs; (ii) ongoing deployment of new applications for querying the contents of the Repository; and (iii) increased harmonization of procedures, data collection strategies, questionnaires etc. across both research studies and within the vocabularies used by different repositories.
Database URL: http://www.niddkrepository.org
The free radical theory of ageing posits that accrual of oxidative damage underlies the increased cellular, tissue and organ dysfunction and failure associated with advanced age. In support of this theory, cellular resistance to oxidative stress is highly correlated with life span, suggesting that prevention or repair of oxidative damage might indeed be essential for longevity. To test the hypothesis that the prevention of oxidative damage underlies longevity, we measured the activities of the five major intracellular antioxidant enzymes in brain, heart and liver tissue of 14 mammalian and avian species with maximum life spans (MLSPs) ranging from 3 years to over 100 years. Our data set included Snell dwarf mice in which life span is increased by ∼50% compared to their normal littermates. We found that CuZn superoxide dismutase, the major cytosolic superoxide dismutase, showed no correlation with MLSP in any of the three organs. Similarly, neither glutathione peroxidase nor glutathione reductase activities correlated with MLSP. MnSOD, the sole mitochondrial superoxide dismutase in mammals and birds, was positively correlated with MLSP only for brain tissue. This same trend was observed for catalase. For all correlational data, effects of body mass and phylogenetic relatedness were removed using residual analysis and Felsenstein’s phylogenetically independent contrasts. Our results are not consistent with a causal role for intracellular antioxidant enzymes in longevity, similar to recent reports from studies utilising genetic modifications of mice (Pérez et al., Biochim Biophys Acta 1790:1005–1014, 2009). However, our results indicate a specific augmentation of reactive oxygen species neutralising activities in brain associated with longevity.
Electronic supplementary material
The online version of this article (doi:10.1007/s11357-010-9131-2) contains supplementary material, which is available to authorized users.
Antioxidant enzyme; Life span; MLSP; Mammals; Birds; MnSOD; CuZnSOD; Catalase; Glutathione peroxidise; Glutathione reductase
Evaluate a social network approach to develop an adolescent cohort for HIV vaccine preparedness and investigate characteristics that influence recruitment.
We summarize baseline data from a prospective cohort study that included four sessions over six months. Fifty-nine HIV-infected adolescent and adult patients of a family-based HIV clinic named significant others and indicated willingness to involve them in this study. Sixty-two adolescent and adult significant others not known to be HIV-infected were enrolled. Logistic regression was used to estimate factors associated with willingness.
Participants identified 624 social network members including 276 (44%) adolescents. Network member's awareness of the index's HIV-positivity (P<0.01) and older age (P=0.05) affected willingness. Respondents were less willing to invite drug-risk alters (P=0.006). Adolescents were willing to invite more adolescents than were adults (P<.0001). Adolescents <18 years old reported fewer sexual and drug-using risk behaviors than expected.
HIV-infected patients are willing to recruit their social networks provided concerns about disclosure of HIV status are addressed. Using social networks to identify and recruit adolescent populations is appropriate and feasible for vaccine preparedness activities, future vaccine trials, and other prevention programs, but procedures are needed to selectively identify and retain high-risk youth.
Social networks; HIV vaccines; HIV vaccine preparedness
We evaluated pain frequency and severity in 339 women enrolled in the Women's Interagency HIV Study (WIHS). Among these, 63% were 39 years of age or younger, 17% were white, 54% African American, and 29% Hispanic; 32% did not complete high school; 58% had a CD4 less than 200; 65% had clinical AIDS; 60% were on highly active antiretroviral therapy (HAART); and 32% had a viral load of 50,000 or more. Data were collected between 1996 and 1998. Within the past 6 months 190 (56%) women experienced pain 6 or more days and 168 (50%) women indicated pain severity scores of 4 or 5 (5-point scale). Pain frequency and pain severity were not associated with age, education, ethnicity, current therapy, or location of the WIHS site. Pain frequency and severity were related to lower CD4 count, higher depression, with a history and longer duration of smoking and use of marijuana. Severity was associated with a history of crack/cocaine or heroin use or with injection drug use as the transmission category. In the multivariate models, pain severity was related to CD4 count and depression and to current tobacco use but not to crack, cocaine, heroin, or marijuana use. Pain frequency was related to depression and to former tobacco, crack, cocaine, heroin, or marijuana use but not to current use. The long-term effects of tobacco use may be to increase pain experience but women may also smoke tobacco or use other substances to give mild pain relief. Pain is frequent and often severe among women with HIV requiring medical management.
Hazardous alcohol consumption among women with human immunodeficiency virus (HIV) infection is associated with several adverse health and behavioral outcomes, but the proportion of HIV-positive women who engage in hazardous drinking over time is unclear. The authors sought to determine rates of hazardous alcohol consumption among these women over time and to identify factors associated with this behavior. Subjects were 2,770 HIV-positive women recruited from 6 US cities who participated in semiannual follow-up visits in the Women's Interagency HIV Study from 1995 to 2006. Hazardous alcohol consumption was defined as exceeding daily (≥4 drinks) or weekly (>7 drinks) consumption recommendations. Over the 11-year follow-up period, 14%–24% of the women reported past-year hazardous drinking, with a slight decrease in hazardous drinking over time. Women were significantly more likely to report hazardous drinking if they were unemployed, were not high school graduates, had been enrolled in the original cohort (1994–1995), had a CD4 cell count of 200–500 cells/mL, were hepatitis C-seropositive, or had symptoms of depression. Approximately 1 in 5 of the women met criteria for hazardous drinking. Interventions to identify and address hazardous drinking among HIV-positive women are urgently needed.
alcohol drinking; HIV; longitudinal studies; women
Our objective was to describe the association that childcare burden, household composition, and health care utilization have with adherence to highly active antiretroviral therapy (HAART) among women in the United States. The primary outcome was 95% or more adherence to HAART evaluated at 10,916 semiannual visits between October 1998 and March 2006 among 1419 HIV-infected participants enrolled in the Women's Interagency HIV Study. HAART adherence levels of 95% or more were reported at 76% of the semiannual visits. At only 4% of the person-visits did women report either quite a bit or extreme difficulty in caring for child; at 52% of the person-visits women reported at least one child 18 years of age or older living in the household. We found a one-unit increase in the difficulty in caring for children (childcare burden was assessed on a 5-point scale: not difficult  to extremely difficult ) was associated with a 6% decreased odds of 95% or more HAART adherence (adjusted odds ratio [OR] = 0.94; p = 0.07). Each additional child 18 years of age or less living in the household was associated with an 8% decreased odds of 95% or more adherence (adjusted OR = 0.92, p = 0.03). Both the number and type of adult living in the household, as well as health care utilization were not associated with HAART adherence. Greater child care burden and number of children 18 years old or younger living in household were both inversely associated with HAART adherence. Assessing patients' difficulties in caring for children and household composition are important factors to consider when addressing adherence to HAART.
We evaluated pain frequency and severity in 339 women enrolled in the Women’s Interagency HIV Study (WIHS). Among these, 63% were 39 years of age or younger, 17% were white, 54% African American, and 29% Hispanic; 32% did not complete high school; 58% had a CD4 less than 200; 65% had clinical AIDS; 60% were on highly active antiretroviral therapy (HAART); and 32% had a viral load of 50,000 or more. Data were collected between 1996 and 1998. Within the past 6 months 190 (56%) women experienced pain 6 or more days and 168 (50%) women indicated pain severity scores of 4 or 5 (5-point scale). Pain frequency and pain severity were not associated with age, education, ethnicity, current therapy, or location of the WIHS site. Pain frequency and severity were related to lower CD4 count, higher depression, with a history and longer duration of smoking and use of marijuana. Severity was associated with a history of crack/cocaine or heroin use or with injection drug use as the transmission category. In the multivariate models, pain severity was related to CD4 count and depression and to current tobacco use but not to crack, cocaine, heroin, or marijuana use. Pain frequency was related to depression and to former tobacco, crack, cocaine, heroin, or marijuana use but not to current use. The long-term effects of tobacco use may be to increase pain experience but women may also smoke tobacco or use other substances to give mild pain relief. Pain is frequent and often severe among women with HIV requiring medical management.
Our objective was to describe the association that childcare burden, household composition, and health care utilization have with adherence to highly active antiretroviral therapy (HAART) among women in the United States. The primary outcome was 95% or more adherence to HAART evaluated at 10,916 semiannual visits between October 1998 and March 2006 among 1419 HIV-infected participants enrolled in the Women’s Interagency HIV Study. HAART adherence levels of 95% or more were reported at 76% of the semiannual visits. At only 4% of the person-visits did women report either quite a bit or extreme difficulty in caring for child; at 52% of the person-visits women reported at least one child 18 years of age or older living in the household. We found a one-unit increase in the difficulty in caring for children (childcare burden was assessed on a 5-point scale: not difficult  to extremely difficult ) was associated with a 6% decreased odds of 95% or more HAART adherence (adjusted odds ratio [OR]=0.94; p=0.07). Each additional child 18 years of age or less living in the household was associated with an 8% decreased odds of 95% or more adherence (adjusted OR=0.92, p=0.03). Both the number and type of adult living in the household, as well as health care utilization were not associated with HAART adherence. Greater child care burden and number of children 18 years old or younger living in household were both inversely associated with HAART adherence. Assessing patients’ difficulties in caring for children and household composition are important factors to consider when addressing adherence to HAART.
The purpose of this work was to evaluate whether living with children adversely affects adherence to highly active antiretroviral therapy in HIV-infected women.
PARTICIPANTS AND METHODS
We conducted a prospective cohort study between October 1998 and September 2005. The study outcome was ≥95% adherence to highly active antiretroviral therapy evaluated at 5832 semiannual visits among 1366 HIV-infected women in the Women’s Interagency HIV Study. The primary exposure defined at the visit immediately before outcome ascertainment was the number of children ≤18 years of age reported living in the household.
The percentage of women who reported ≥2 children in the household who also reported ≥95% adherence ranged from 68% to 75% compared with adherence when either 1 child or no children were reported. Each additional child reported living in the household was associated with a 6% decrease in the odds of ≥95% adherence.
The impact of living with a child on the ability to take medications by HIV-infected women has not been examined thoroughly. Our data suggest that adherence to highly active antiretroviral therapy is inversely associated with the number of children living in the household.
adherence; children; HAART; HIV
Recent studies have examined the presence of mouse allergen in inner city children with asthma. Researchers have found high levels of rodent allergen in homes sampled in the northeast and midwest United States, but there has been considerable variation between cities, and there have been few studies conducted in western states. We evaluated the frequency of rodent sightings and detectable mouse allergen and the housing conditions associated with these outcomes in inner city homes in Los Angeles. Two hundred and two families of school children, ages 6–16 living in inner city neighborhoods, participated in the study. Families were predominantly Latino (94%), and Spanish speaking (92%). At study entry, parents completed a home assessment questionnaire, and staff conducted a home evaluation and collected kitchen dust, which was analyzed for the presence of mouse allergen. Fifty-one percent of homes had detectable allergen in kitchen dust. All 33 families who reported the presence of rodents had detectable allergen in the home and were also more likely to have increased levels of allergen compared to those who did not report rodents. Unwashed dishes or food crumbs, lack of a working vacuum, and a caretaker report of a smoker in the home were all significantly associated with a greater risk of rodent sightings or detectable allergen (P < 0.05). Detached homes were significantly more likely to have detectable allergen. The prevalence of allergen is common enough that it may have public health implications for asthmatic children, and detectable allergen was not routinely identified based on rodent sightings. Many of the predictors of rodent allergen are amenable to low-cost interventions that can be integrated with other measures to reduce exposure to indoor allergens.
Asthma; Mouse allergen; House dust; Rodent; Environment
The correlates of unprotected sex among a sample of heterosexual men living with HIV (n = 121) were examined to determine whether patient characteristics can be used as a basis for tailoring safer sex counseling in the clinic setting. Potential correlates of self-reported unprotected oral sex (fellatio) and vaginal sex included participant demographics (e.g., age, ethnicity), disease status (CD4 counts, viral load, years since diagnosis), safer sex beliefs (e.g., condom attitudes), substance use, psychological characteristics (depressive symptoms, dispositional optimism and pessimism), and sex partner characteristics (main/casual partner, HIV status of partner, and duration of relationship). A series of logistic regression analyses were used to determine significant relationships. Correlates of reported levels of prior 3-month unprotected fellatio (24%) and vaginal (21%) sex were not associated with the type of relationship (main or casual) or perceived HIV serostatus of the partner (positive, negative, or unknown). Unprotected fellatio was positively associated with age and CD4 count and inversely associated with optimism and positive condom attitudes (all p's < 0.05). Unprotected vaginal sex was positively associated with duration of relationship and inversely associated with positive condom attitudes. Prevention efforts among sexually active adult heterosexual men living with HIV may benefit from focusing on improving attitudes towards condom use regardless of partner relationship status.
Condom attitudes; Heterosexual; HIV; Optimism; Unsafe sex