Cytotoxic T lymphocytes (CTL) can control some viral infections and may be important in the control of lentiviruses, including human immunodeficiency virus type 1. Since there is limited evidence for ...an in vivo role of CTL in control of lentiviruses, dissection of immune mechanisms in animal lentiviral infections may provide needed information. Horses infected with equine infectious anemia virus (EIAV), a lentivirus, have acute plasma viremia which is terminated in immunocompetent horses. Viremic episodes may recur, but most horses ultimately control infection and become asymptomatic carriers. To begin dissection of the immune mechanisms involved in EIAV control, peripheral blood mononuclear cells (PBMC) from infected horses were evaluated for CTL to EIAV-infected cells. By using noninfected and EIAV-infected autologous equine kidney (EK) cells in 51Cr-release assays, EIAV-specific cytotoxic activity was detected in unstimulated PBMC from three infected horses. The EIAV-specific cytotoxic activity was major histocompatibility complex (MHC) restricted, as determined by assaying EIAV-infected heterologous EK targets, and was mediated by CD8+ T lymphocytes, as determined by depleting these cells by a panning procedure with an anti-CD8 monoclonal antibody. MHC-restricted CD8+ CTL in unstimulated PBMC from infected horses caused significant specific lysis of autologous EK cells infected with recombinant vaccinia viruses expressing EIAV genes, either env or gag plus 5' pol. The EIAV-specific MHC-restricted CD8+ CTL were detected in two EIAV-infected horses within a few days after plasma viremia occurred and were present after viremia was terminated. The detection of these immune effector cells in EIAV-infected horses permits further studies to determine their in vivo role
Natural scientists have long recognized that regions with similar climate tend to have similar vegetation. Preliminary observations suggest that shrub steppe communities of the western US and western ...China may be two such regions with similar annual precipitation, temperature, land use, and vegetation. These cold dry shrub steppes have traditionally been grazed. Despite these similarities, patterns of species dominance are different. Annual species that are rare in China become dominant when introduced to the United States. The objective of this study was to investigate how climate, land use and community structure may explain these patterns of species dominance. Community structure and grazing intensity were measured at 5 sites in each region. This information was combined with a broader review of the literature describing the history of grazing in both basins. Climate was analyzed based on a spatially-gridded, interpolated weather time series (monthly records) and climatological summary (1961–1990 mean conditions) data set from the Climate Research Unit. We found that differences in summer precipitation and winter minimum temperature, land use intensity, and shrub size may all contribute to the dominance of annual species in the Great Basin, particularly
Bromus tectorum
. In particular, previous work indicates that summer precipitation and winter temperature drive the distribution of
Bromus tectorum
in the Great Basin. As a result, sites with wet summers and cold springs, similar to the Chinese sites, would not be expected to be dominated by
Bromus tectorum
. A history of more intense grazing of the Chinese sites, as described in the literature, also is likely to decrease fire frequency, and decreases litter and shrub dominance, all of which have been demonstrated to be important in
Bromus tectorum
establishment and ultimate dominance. Further research is necessary to determine if other annuals that follow the same pattern of scarcity in the Junggar Basin and dominance in the Great Basin are responding to the same influences.
We performed a multicenter, double-blind, randomized study to evaluate the effect of diltiazem on reinfarction after a non-Q-wave myocardial infarction. Nine centers enrolled 576 patients: 287 ...received diltiazem (90 mg every six hours) and 289 received placebo. Treatment was initiated 24 to 72 hours after the onset of infarction and continued for up to 14 days. The primary end point, reinfarction, was defined as an abnormal reelevation of MB creatine kinase in plasma within 14 days. Reinfarction occurred in 27 patients in the placebo group (9.3 percent) and in 15 in the diltiazem group (5.2 percent)--a 51.2 percent reduction in cumulative life-table incidence (P = 0.0297; 90 percent confidence interval, 7 to 67 percent). Diltiazem reduced the frequency of refractory postinfarction angina (a secondary end point) by 49.7 percent (P = 0.0345; 90 percent confidence interval, 6 to 73 percent). Mortality was similar in the two groups (3.1 and 3.8 percent, respectively, in the placebo and diltiazem groups), but adverse drug reactions (most of which were mild) were more common in the diltiazem group. Nevertheless, the drug was well tolerated, despite concurrent treatment with beta-blockers in 61 percent of the patients. We conclude that diltiazem was effective in preventing early reinfarction and severe angina after non-Q-wave infarction and that it was also safe and generally well tolerated.
Saturn’s moon Enceladus has an ice-covered ocean; a plume of material erupts from cracks in the ice. The plume contains chemical signatures of water-rock interaction between the ocean and a rocky ...core. We used the Ion Neutral Mass Spectrometer onboard the Cassini spacecraft to detect molecular hydrogen in the plume. By using the instrument’s open-source mode, background processes of hydrogen production in the instrument were minimized and quantified, enabling the identification of a statistically significant signal of hydrogen native to Enceladus. We find that the most plausible source of this hydrogen is ongoing hydrothermal reactions of rock containing reduced minerals and organic materials. The relatively high hydrogen abundance in the plume signals thermodynamic disequilibrium that favors the formation of methane from CO₂ in Enceladus’ ocean.
Metal contamination of food and water resources is a known public health issue in Arctic and sub-Arctic communities due to the proximity of many communities to mining and drilling sites. In addition, ...permafrost thaw may release heavy metals sequestered in previously frozen soils, potentially contaminating food and water resources by increasing the concentration of metals in freshwater, plants, and wildlife. Here we assess the enrichment of selected heavy metals in Alaskan soils by synthesizing publicly available data of soil metal concentrations. We analyzed data of soil concentrations of arsenic, chromium, mercury, nickel, and lead from over 1,000 samples available through the USGS Alaskan Geochemical Database to evaluate 1) the spatial distribution of sampling locations for soil metal analysis, 2) metal concentrations in soils from different land cover types and depths, and 3) the occurrence of soils in Alaska with elevated metal concentrations relative to other soils. We found substantial clustering of sample sites in the southwestern portion of Alaska in discontinuous and sporadic permafrost, while the continuous permafrost zone in Northern Alaska and the more populous Interior are severely understudied. Metal concentration varied by land cover type but lacked consistent patterns. Concentrations of chromium, mercury, and lead were higher in soils below 10 cm depth, however these deeper soils are under-sampled. Arsenic, chromium, mercury, nickel and lead concentrations exceeded average values for US soils by one standard deviation or more in 3.7% to 18.7% of the samples in this dataset. Our analysis highlights critical gaps that impede understanding of how heavy metals in thawing permafrost soils may become mobilized and increase exposure risk for Arctic communities.
Racial disparities in access to renal transplantation exist, but the effects of race and socioeconomic status (SES) on early steps of renal transplantation have not been well explored. Adult patients ...referred for renal transplant evaluation at a single transplant center in the Southeastern United States from 2005 to 2007, followed through May 2010, were examined. Demographic and clinical data were obtained from patient's medical records and then linked with United States Renal Data System and American Community Survey Census data. Cox models examined the effect of race on referral, evaluation, waitlisting and organ receipt. Of 2291 patients, 64.9% were black, the mean age was 49.4 years and 33.6% lived in poor neighborhoods. Racial disparities were observed in access to referral, transplant evaluation, waitlisting and organ receipt. SES explained almost one‐third of the lower rate of transplant among black versus white patients, but even after adjustment for demographic, clinical and SES factors, blacks had a 59% lower rate of transplant than whites (hazard ratio = 0.41; 95% confidence interval: 0.28–0.58). Results suggest that improving access to healthcare may reduce some, but not all, of the racial disparities in access to kidney transplantation.
In a population of patients referred for kidney transplantation in the Southeastern United States, racial disparities persist even after accounting for individual‐ and census‐tract neighborhood‐level socioeconomic differences, where black patients had a 59% lower rate of transplant than white patients. See AJT Report (page 269) and article by Patzer et al on page 369.
Many shark and ray species show affinity to specific sites, making these areas critical for their survival. These include cleaning stations: locations on reefs where cleaner fish remove parasites and ...clean wounds, which is important for maintaining health. Cleaning stations also function as social gathering sites, or resting points, where courtship and mating can occur. In this study, we identify an aggregation site for the shortfin devil ray,
Mobula kuhlii
(Family Mobulidae) within the Aliwal Shoal Marine Protected Area in KwaZulu-Natal (KZN), South Africa, and document their behavior. Remote underwater video was used to collect footage of
M. kuhlii
being cleaned by blue streak cleaner wrasse,
Labroides dimidiatus
. Generalized additive models (GAMs) were used to assess environmental predictors of
M. kuhlii
presence on Aliwal Shoal. Mixed models were used to assess the same environmental predictors and their correlation with mean
M. kuhlii
cleaning duration and number of
L. dimidiatus
bites per second at the identified cleaning station site.
M. kuhlii
were present in 56% of observation days, with group numbers up to > 150 individuals. Sea surface temperature was a significant predictor for
M. kuhlii
presence, while a north to south current was significantly associated with longer mean cleaning durations. These results support findings of mobulid studies in KZN that show increased habitat use during summer temperatures (24–25 °C) and suggest these sites to be important for individual health and social interaction. We hope these findings can be used for development of location-specific management plans to safeguard this Endangered species.
Plastic waste inputs from land into the ocean Jambeck, Jenna R.; Geyer, Roland; Wilcox, Chris ...
Science (American Association for the Advancement of Science),
02/2015, Letnik:
347, Številka:
6223
Journal Article
Recenzirano
Plastic debris in the marine environment is widely documented, but the quantity of plastic entering the ocean from waste generated on land is unknown. By linking worldwide data on solid waste, ...population density, and economic status, we estimated the mass of land-based plastic waste entering the ocean. We calculate that 275 million metric tons (MT) of plastic waste was generated in 192 coastal countries in 2010, with 4.8 to 12.7 million MT entering the ocean. Population size and the quality of waste management systems largely determine which countries contribute the greatest mass of uncaptured waste available to become plastic marine debris. Without waste management infrastructure improvements, the cumulative quantity of plastic waste available to enter the ocean from land is predicted to increase by an order of magnitude by 2025.
Racial disparities persist in access to renal transplantation in the United States, but the degree to which patient and neighborhood socioeconomic status (SES) impacts racial disparities in deceased ...donor renal transplantation access has not been examined in the pediatric and adolescent end‐stage renal disease (ESRD) population. We examined the interplay of race and SES in a population‐based cohort of all incident pediatric ESRD patients <21 years from the United States Renal Data System from 2000 to 2008, followed through September 2009. Of 8 452 patients included, 30.8% were black, 27.6% white‐Hispanic, 44.3% female and 28.0% lived in poor neighborhoods. A total of 63.4% of the study population was placed on the waiting list and 32.5% received a deceased donor transplant. Racial disparities persisted in transplant even after adjustment for SES, where minorities were less likely to receive a transplant compared to whites, and this disparity was more pronounced among patients 18–20 years. Disparities in access to the waiting list were mitigated in Hispanic patients with private health insurance. Our study suggests that racial disparities in transplant access worsen as pediatric patients transition into young adulthood, and that SES does not explain all of the racial differences in access to kidney transplantation.
Findings from this national cohort of pediatric end‐stage renal disease patients suggest that racial disparities exist in access to kidney transplantation that are not entirely explained by socioeconomic status, and are more pronounced among patients transitioning into young adulthood. See AJT Report (page 269) and article by Patzer et al on page 358.
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