Regional Effects of Agricultural Conservation Practices on Nutrient Transport in the Upper Mississippi River Basin.

Despite progress in the implementation of conservation practices, related improvements in water quality have been challenging to measure in larger river systems. In this paper we quantify these downstream effects by applying the empirical U.S. Geological Survey water-quality model SPARROW to investigate whether spatial differences in conservation intensity were statistically correlated with variations in nutrient loads. In contrast to other forms of water quality data analysis, the application of SPARROW controls for confounding factors such as hydrologic variability, multiple sources and environmental processes. A measure of conservation intensity was derived from the USDA-CEAP regional assessment of the Upper Mississippi River and used as an explanatory variable in a model of the Upper Midwest. The spatial pattern of conservation intensity was negatively correlated (p = 0.003) with the total nitrogen loads in streams in the basin. Total phosphorus loads were weakly negatively correlated with conservation (p = 0.25). Regional nitrogen reductions were estimated to range from 5 to 34% and phosphorus reductions from 1 to 10% in major river basins of the Upper Mississippi region. The statistical associations between conservation and nutrient loads are consistent with hydrological and biogeochemical processes such as denitrification. The results provide empirical evidence at the regional scale that conservation practices have had a larger statistically detectable effect on nitrogen than on phosphorus loadings in streams and rivers of the Upper Mississippi Basin.

Immunostimulatory early phenotype of tumor-associated macrophages does not predict tumor growth outcome in an HLA-DR mouse model of prostate cancer.

Tumor-associated macrophages (TAM) were shown to support the progression of many solid tumors. However, anti-tumor properties of TAM were also reported in several types of cancer. Here, we investigated the phenotype and functions of TAM in two transgenic mouse models of prostate cancer that display striking differences in tumor growth outcome. Mice expressing prostate-specific antigen (PSA) as a self-antigen specifically in prostate (PSAtg mice) rejected PSA-expressing transgenic adenocarcinoma of mouse prostate (TRAMP) tumors. However, the introduction of HLA-DRB1*1501 (DR2b) transgene presenting PSA-derived peptides in a MHC class II-restricted manner exacerbated the growth of TRAMP-PSA tumors in DR2bxPSA F 1 mice. Despite the difference in tumor growth outcome, tumors in both strains were equally and intensively infiltrated by macrophages on the first week after tumor challenge. TAM exhibited mixed M1/M2 polarization and simultaneously produced pro-inflammatory (TNFα, IL1ß) and anti-inflammatory (IL10) cytokines. TAM from both mouse strains demonstrated antigen-presenting potential and pronounced immunostimulatory activity. Moreover, they equally induced apoptosis of tumor cells. In vivo depletion of macrophages in DR2bxPSA F 1 but not PSAtg mice aggravated tumor growth suggesting that macrophages more strongly contribute to anti-tumor immunity when specific presentation of PSA to CD4+ T cells is possible. In summary, we conclude that in the early stages of tumor progression, the phenotype and functional properties of TAM did not predict tumor growth outcome in two transgenic prostate cancer models. Furthermore, we demonstrated that during the initial stage of prostate cancer development, TAM have the potential to activate T cell immunity and mediate anti-tumor effects.

Breaking immune tolerance by targeting CD25+ regulatory T cells is essential for the anti-tumor effect of the CTLA-4 blockade in an HLA-DR transgenic mouse model of prostate cancer.

INTRODUCTION: Recent studies suggest that the cancer immunotherapy based on the blockade of the CTLA-4-mediated inhibitory pathway is efficacious only in select populations, predominantly for immunogenic tumors or when delivered in combination with modalities that can break immunologic tolerance to tumor antigens. METHODS: We studied the effect of CD25+ cell depletion and CTLA-4 blockade on the growth of Transgenic Mouse Adenocarcinoma of Prostate (TRAMP)-PSA tumor cells in DR2bxPSA F1 mice. In these mice, immunological tolerance to PSA was established in a context of the HLA-DRB1*1501(DR2b) allele. RESULTS: In our model, single administration of anti-CD25 antibody prior to tumor inoculation significantly increased IFN-γ production in response to the CD8 T cell epitope PSA65-73 , and delayed TRAMP-PSA tumor growth compared to mice treated with isotype control antibodies. In contrast, the anti-tumor effect of the anti-CTLA-4 antibody as a monotherapy was marginal. The combinatory treatment with anti-CD25/anti-CTLA-4 antibodies significantly enhanced anti-tumor immunity and caused more profound delay in tumor growth compared to each treatment alone. The proportion of tumor-free animals was higher in the group that received combination treatment (21%) compared to other groups (2-7%). The enhanced anti-tumor immunity in response to the CD25 depletion or CTLA-4 blockade was only seen in the immunogenic TRAMP-PSA tumor model, whereas the effect was completely absent in mice bearing poorly immunogenic TRAMP-C1 tumors. DISCUSSION: Our data suggest that breaking immunological tolerance to "self" antigens is essential for the therapeutic effect of CTLA-4 blockade. Such combinatory treatment may be a promising approach for prostate cancer immunotherapy.

MicroRNA-1 is a candidate tumor suppressor and prognostic marker in human prostate cancer.

We previously reported that miR-1 is among the most consistently down-regulated miRs in primary human prostate tumors. In this follow-up study, we further corroborated this finding in an independent data set and made the novel observation that miR-1 expression is further reduced in distant metastasis and is a candidate predictor of disease recurrence. Moreover, we performed in vitro experiments to explore the tumor suppressor function of miR-1. Cell-based assays showed that miR-1 is epigenetically silenced in human prostate cancer. Overexpression of miR-1 in these cells led to growth inhibition and down-regulation of genes in pathways regulating cell cycle progression, mitosis, DNA replication/repair and actin dynamics. This observation was further corroborated with protein expression analysis and 3'-UTR-based reporter assays, indicating that genes in these pathways are either direct or indirect targets of miR-1. A gene set enrichment analysis revealed that the miR-1-mediated tumor suppressor effects are globally similar to those of histone deacetylase inhibitors. Lastly, we obtained preliminary evidence that miR-1 alters the cellular organization of F-actin and inhibits tumor cell invasion and filipodia formation. In conclusion, our findings indicate that miR-1 acts as a tumor suppressor in prostate cancer by influencing multiple cancer-related processes and by inhibiting cell proliferation and motility.

CD4 T-Cell-mediated immune response to prostatic proteins in HLA-DRB1*1503 transgenic mice and identification of a novel HLA-DRB1*1503-restricted T-cell epitope from human prostatic acid phosphatase.

BACKGROUND: Transgenic mice engineered to express human leukocyte antigen (HLA) alleles are widely used for identification of immunogenic and naturally processed epitopes. Using HLA-DRB1*1501 (DR2b) transgenic mice, we have previously identified epitopes from two prostatic antigens, prostate-specific antigen (PSA) and prostatic acid phosphatase (PAP). These antigens are implicated in the development of autoimmunity in the prostate and also are considered promising targets for prostate cancer immunotherapy. HLA-DRB1*1501 is the most common DR15 allele in Caucasians, while HLA-DRB1*1503 is the most common in African Americans. Hence characterization of peptide immunogenicity for these alleles is important for the development of prostate cancer immunotherapy in white and black patients. METHODS: HLA-DRB1*1501 or HLA-DRB1*1503 transgenic mice were immunized with human PSA or PAP. Libraries of overlapping 20-mer peptides spanning the entire sequences of these proteins were screened by IFN-γ ELISPOT assay. RESULTS: PSA and PAP peptides that were previously identified in HLA-DRB1*1501 tg mice were immunogenic in HLA-DR1503 tg mice and induced CD4 T-cell response against whole processed PSA or PAP respectively. However, the hierarchy of the immunodominance among the peptides differed significantly between strains. Using HLA-DRB1*1503 tg mice, a novel immunogenic and naturally processed 20-mer peptide, PAP (233-252) has been identified that showed no reactivity in HLA-DRB1*1501 tg mice. CONCLUSIONS: Our data demonstrate a disparity in CD4 T-cell immune reactivity to PSA and PAP between HLA-DRB1*1501 and -DRB1*1503 alleles in HLA transgenic mouse models. It is possible that such immunological differences could contribute to racial disparity in prostate cancer outcome.

Alfuzosin and symptoms of chronic prostatitis-chronic pelvic pain syndrome.

BACKGROUND: In men with chronic prostatitis-chronic pelvic pain syndrome, treatment with alpha-adrenergic receptor blockers early in the course of the disorder has been reported to be effective in some, but not all, relatively small randomized trials. METHODS: We conducted a multicenter, randomized, double-blind, placebo-controlled trial to evaluate the efficacy of alfuzosin, an alpha-adrenergic receptor blocker, in reducing symptoms in men with chronic prostatitis-chronic pelvic pain syndrome. Participation in the study required diagnosis of the condition within the preceding 2 years and no previous treatment with an alpha-adrenergic receptor blocker. Men were randomly assigned to treatment for 12 weeks with either 10 mg of alfuzosin per day or placebo. The primary outcome was a reduction of at least 4 points (from baseline to 12 weeks) in the score on the National Institutes of Health Chronic Prostatitis Symptom Index (NIH-CPSI) (range, 0 to 43; higher scores indicate more severe symptoms). A 4-point decrease is the minimal clinically significant difference in the score. RESULTS: A total of 272 eligible participants underwent randomization, and in both study groups, 49.3% of participants had a decrease of at least 4 points in their total NIH-CPSI score (rate difference associated with alfuzosin, 0.1%; 95% confidence interval, -11.2 to 11.0; P=0.99). In addition, a global response assessment showed similar response rates at 12 weeks: 33.6% in the placebo group and 34.8% in the alfuzosin group (P=0.90). The rates of adverse events in the two groups were also similar. CONCLUSIONS: Our findings do not support the use of alfuzosin to reduce the symptoms of chronic prostatitis-chronic pelvic pain syndrome in men who have not received prior treatment with an alpha-blocker. (ClinicalTrials.gov number, NCT00103402.)

Cutting edge: permissive MHC class II allele changes the pattern of antitumor immune response resulting in failure of tumor rejection.

We studied the growth of transgenic adenocarcinoma of mouse prostate (TRAMP)-C1 tumor cells expressing human prostate-specific Ag (PSA) in HLA-DRB1*1501 (DR2b) transgenic mice. TRAMP-PSA tumors were frequently rejected by HLA-DR2b(-) mice but had increased incidence in HLA-DR2b(+) littermates. The levels of PSA-specific CD8 T cell responses were significantly higher in the HLA-DR2b(-) mice that rejected TRAMP-PSA tumors compared with HLA-DR2b(+) tumor-bearing littermates. In contrast, Ab responses to PSA were strong in HLA-DR2b(+) mice bearing TRAMP-PSA tumors and were virtually undetectable in HLA-DR2b(-) littermates. The analysis of CD4 T cell responses to PSA revealed the presence of several CD4 T cell epitopes in HLA-DR2b(+) mice but failed to identify strong I-A(b)-restricted epitopes in HLA-DR2b(-) mice. Our data demonstrate that the expression of a permissive HLA class II allele can change the pattern of the immune response to a tumor Ag, resulting in the failure of tumor rejection.

Factors Affecting Stream Nutrient Loads: A Synthesis of Regional SPARROW Model Results for the Continental United States.

We compared the results of 12 recently calibrated regional SPARROW (SPAtially Referenced Regressions On Watershed attributes) models covering most of the continental United States to evaluate the consistency and regional differences in factors affecting stream nutrient loads. The models - 6 for total nitrogen and 6 for total phosphorus - all provide similar levels of prediction accuracy, but those for major river basins in the eastern half of the country were somewhat more accurate. The models simulate long-term mean annual stream nutrient loads as a function of a wide range of known sources and climatic (precipitation, temperature), landscape (e.g., soils, geology), and aquatic factors affecting nutrient fate and transport. The results confirm the dominant effects of urban and agricultural sources on stream nutrient loads nationally and regionally, but reveal considerable spatial variability in the specific types of sources that control water quality. These include regional differences in the relative importance of different types of urban (municipal and industrial point vs. diffuse urban runoff) and agriculture (crop cultivation vs. animal waste) sources, as well as the effects of atmospheric deposition, mining, and background (e.g., soil phosphorus) sources on stream nutrients. Overall, we found that the SPARROW model results provide a consistent set of information for identifying the major sources and environmental factors affecting nutrient fate and transport in United States watersheds at regional and subregional scales.

The Regionalization of National-Scale SPARROW Models for Stream Nutrients.

This analysis modifies the parsimonious specification of recently published total nitrogen (TN) and total phosphorus (TP) national-scale SPAtially Referenced Regressions On Watershed attributes models to allow each model coefficient to vary geographically among three major river basins of the conterminous United States. Regionalization of the national models reduces the standard errors in the prediction of TN and TP loads, expressed as a percentage of the predicted load, by about 6 and 7%. We develop and apply a method for combining national-scale and regional-scale information to estimate a hybrid model that imposes cross-region constraints that limit regional variation in model coefficients, effectively reducing the number of free model parameters as compared to a collection of independent regional models. The hybrid TN and TP regional models have improved model fit relative to the respective national models, reducing the standard error in the prediction of loads, expressed as a percentage of load, by about 5 and 4%. Only 19% of the TN hybrid model coefficients and just 2% of the TP hybrid model coefficients show evidence of substantial regional specificity (more than ±100% deviation from the national model estimate). The hybrid models have much greater precision in the estimated coefficients than do the unconstrained regional models, demonstrating the efficacy of pooling information across regions to improve regional models.

T-cell recognition of prostatic peptides in men with chronic prostatitis/chronic pelvic pain syndrome.

PURPOSE: A potential etiology of chronic prostatitis/chronic pelvic pain syndrome is autoimmunity. We determined whether T cells from men with chronic prostatitis/chronic pelvic pain syndrome would recognize peptides derived from the normal self-prostatic proteins prostate specific antigen and prostatic acid phosphatase. MATERIALS AND METHODS: CD4 T cells purified from peripheral blood of 31 patients with chronic prostatitis/chronic pelvic pain syndrome and from the buffy coat preparation of 27 normal male blood donors were stimulated in vitro with a panel of immunogenic peptides from prostate specific antigen and prostatic acid phosphatase, and assayed for reactivity with the peptides by interferon-gamma enzyme-linked immunosorbent spot assay. Intermediate resolution HLA typing was done by polymerase chain reaction. Peptides were also tested by binding assay against different class II alleles. RESULTS: Peptide PAP(173-192) was recognized more frequently by CD4 T cells from patients with chronic prostatitis/chronic pelvic pain syndrome than from healthy donors. The recognition of prostate specific antigen peptides was not statistically different when comparing cases to normal male blood donors individually. Peptide reactivity was more common in patients than in normal male blood donors for any prostate specific antigen peptide or any tested peptide. All peptides showed high promiscuity on binding assays. There was no association of cases with any specific HLA class II phenotype at intermediate resolution. CONCLUSIONS: CD4 T cells from patients with chronic prostatitis/chronic pelvic pain syndrome have a higher rate of recognizing the self-prostatic proteins prostatic acid phosphatase and prostate specific antigen compared to those from normal male blood donors. Data provide further evidence to support the role of autoimmunity in some men with chronic prostatitis/chronic pelvic pain syndrome.

Incorporating Uncertainty Into the Ranking of SPARROW Model Nutrient Yields From Mississippi/Atchafalaya River Basin Watersheds.

Excessive loads of nutrients transported by tributary rivers have been linked to hypoxia in the Gulf of Mexico. Management efforts to reduce the hypoxic zone in the Gulf of Mexico and improve the water quality of rivers and streams could benefit from targeting nutrient reductions toward watersheds with the highest nutrient yields delivered to sensitive downstream waters. One challenge is that most conventional watershed modeling approaches (e.g., mechanistic models) used in these management decisions do not consider uncertainties in the predictions of nutrient yields and their downstream delivery. The increasing use of parameter estimation procedures to statistically estimate model coefficients, however, allows uncertainties in these predictions to be reliably estimated. Here, we use a robust bootstrapping procedure applied to the results of a previous application of the hybrid statistical/mechanistic watershed model SPARROW (Spatially Referenced Regression On Watershed attributes) to develop a statistically reliable method for identifying "high priority" areas for management, based on a probabilistic ranking of delivered nutrient yields from watersheds throughout a basin. The method is designed to be used by managers to prioritize watersheds where additional stream monitoring and evaluations of nutrient-reduction strategies could be undertaken. Our ranking procedure incorporates information on the confidence intervals of model predictions and the corresponding watershed rankings of the delivered nutrient yields. From this quantified uncertainty, we estimate the probability that individual watersheds are among a collection of watersheds that have the highest delivered nutrient yields. We illustrate the application of the procedure to 818 eight-digit Hydrologic Unit Code watersheds in the Mississippi/Atchafalaya River basin by identifying 150 watersheds having the highest delivered nutrient yields to the Gulf of Mexico. Highest delivered yields were from watersheds in the Central Mississippi, Ohio, and Lower Mississippi River basins. With 90% confidence, only a few watersheds can be reliably placed into the highest 150 category; however, many more watersheds can be removed from consideration as not belonging to the highest 150 category. Results from this ranking procedure provide robust information on watershed nutrient yields that can benefit management efforts to reduce nutrient loadings to downstream coastal waters, such as the Gulf of Mexico, or to local receiving streams and reservoirs.

Psychosocial variables affect the quality of life of men diagnosed with chronic prostatitis/chronic pelvic pain syndrome.

OBJECTIVE: To examine interactions between demographic, pain, urinary, psychological and environmental predictors of quality of life (QOL) in men with chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS). PATIENTS AND METHODS: In all, 253 men previously enrolled in the National Institutes of Health Chronic Prostatitis Cohort study in North American tertiary-care clinical centres (six in the USA and one in Canada) self-reported with validated instruments, including the QOL subscales of the Short Form-12 (physical, SF12-PCS; and mental, SF12-MCS), demographics, urinary symptoms, depression, current pain, pain coping, 'catastrophizing' (catastrophic thinking about pain), pain control, social support and solicitous responses from a partner. Data were collected through a one-time survey. Covariates determined to be significant were entered into a multivariable regression model predicting SF12-PCS and SF12-MCS. RESULTS: Adjusting for covariates, regression models showed that poorer SF12-PCS scores were predicted by worse urinary function (P < 0.001) and increased use of pain-contingent resting as a coping strategy (P = 0.026). Further, poorer SF12-MCS scores were predicted by greater pain catastrophizing (P = 0.002) and lower perceptions of social support (P< 0.001). In separate follow-up analyses, helplessness was the significant catastrophizing subscale (P < 0.001), while support from family and friends were the significant social support subscales (P = 0.002 and <0.001). CONCLUSIONS: These data suggest that specific coping and environmental factors (i.e. catastrophizing, pain-contingent resting, social support) are significant in understanding how patients with CP/CPPS adjust. These data can be used to develop specific cognitive-behavioural programmes for men with CP/CPPS who are refractory to standard medical therapy.

Category III chronic prostatitis/chronic pelvic pain syndrome: insights from the National Institutes of Health Chronic Prostatitis Collaborative Research Network studies.

Chronic prostatitis/chronic pelvic pain syndrome remains an enigmatic medical condition. Creation of the National Institutes of Health-funded Chronic Prostatitis Collaborative Research Network (CPCRN) has stimulated a renewed interest in research on and clinical aspects of chronic prostatitis/chronic pelvic pain syndrome. Landmark publications of the CPCRN document a decade of progress. Insights from these CPCRN studies have improved our management of chronic prostatitis/chronic pelvic pain syndrome and offer hope for continued progress.

Thresholds of lake and reservoir connectivity in river networks control nitrogen removal.

Lakes, reservoirs, and other ponded waters are ubiquitous features of the aquatic landscape, yet their cumulative role in nitrogen removal in large river basins is often unclear. Here we use predictive modeling, together with comprehensive river water quality, land use, and hydrography datasets, to examine and explain the influences of more than 18,000 ponded waters on nitrogen removal through river networks of the Northeastern United States. Thresholds in pond density where ponded waters become important features to regional nitrogen removal are identified and shown to vary according to a ponded waters' relative size, network position, and degree of connectivity to the river network, which suggests worldwide importance of these new metrics. Consideration of the interacting physical and biological factors, along with thresholds in connectivity, reveal where, why, and how much ponded waters function differently than streams in removing nitrogen, what regional water quality outcomes may result, and in what capacity management strategies could most effectively achieve desired nitrogen loading reduction.

The Role of Headwater Streams in Downstream Water Quality.

Knowledge of headwater influences on the water-quality and flow conditions of downstream waters is essential to water-resource management at all governmental levels; this includes recent court decisions on the jurisdiction of the Federal Clean Water Act (CWA) over upland areas that contribute to larger downstream water bodies. We review current watershed research and use a water-quality model to investigate headwater influences on downstream receiving waters. Our evaluations demonstrate the intrinsic connections of headwaters to landscape processes and downstream waters through their influence on the supply, transport, and fate of water and solutes in watersheds. Hydrological processes in headwater catchments control the recharge of subsurface water stores, flow paths, and residence times of water throughout landscapes. The dynamic coupling of hydrological and biogeochemical processes in upland streams further controls the chemical form, timing, and longitudinal distances of solute transport to downstream waters. We apply the spatially explicit, mass-balance watershed model SPARROW to consider transport and transformations of water and nutrients throughout stream networks in the northeastern United States. We simulate fluxes of nitrogen, a primary nutrient that is a water-quality concern for acidification of streams and lakes and eutrophication of coastal waters, and refine the model structure to include literature observations of nitrogen removal in streams and lakes. We quantify nitrogen transport from headwaters to downstream navigable waters, where headwaters are defined within the model as first-order, perennial streams that include flow and nitrogen contributions from smaller, intermittent and ephemeral streams. We find that first-order headwaters contribute approximately 70% of the mean-annual water volume and 65% of the nitrogen flux in second-order streams. Their contributions to mean water volume and nitrogen flux decline only marginally to about 55% and 40% in fourth- and higher-order rivers that include navigable waters and their tributaries. These results underscore the profound influence that headwater areas have on shaping downstream water quantity and water quality. The results have relevance to water-resource management and regulatory decisions and potentially broaden understanding of the spatial extent of Federal CWA jurisdiction in U.S. waters.

Catastrophizing and pain-contingent rest predict patient adjustment in men with chronic prostatitis/chronic pelvic pain syndrome.

UNLABELLED: Cognitive/behavioral and environmental variables are significant predictors of patient adjustment in chronic pain. Using a biopsychosocial template and selecting several pain-relevant constructs from physical, cognitive/behavioral, and environmental predictors, outcomes of pain and disability in chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) were explored. Men (n = 253) from a North American multi-institutional NIH-funded Chronic Prostatitis Cohort Study in 6 US and 1 Canadian centers participated in a survey examining pain and disability. Measures included demographics, urinary symptoms, depression, pain, disability, catastrophizing, control over pain, pain-contingent rest, social support, and solicitous responses from a significant other. Regressions showed that urinary symptoms (beta = .20), depression (beta = .24), and helplessness catastrophizing (beta = .29) predicted overall pain. Further, affective pain was predicted by depression (beta = .39) and helplessness catastrophizing (beta = .44), whereas sensory pain was predicted by urinary symptoms (beta = .25) and helplessness catastrophizing (beta = .37). With regard to disability, urinary symptoms (beta = .17), pain (beta = .21), and pain-contingent rest (beta = .33) were the predictors. These results suggest cognitive/behavioral variables (ie, catastrophizing, pain-contingent rest) may have significant impact on patient adjustment in CP/CPPS. Findings support the need for greater research of such pain-related variables in CP/CPPS. PERSPECTIVE: This article explores predictors of patient adjustment in chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS). Cognitive/behavioral variables of catastrophizing and pain-contingent rest respectively predicted greater pain and disability. Catastrophic helplessness was a prominent pain predictor. These findings inform clinicians and researchers on several new variables in CP/CPPS outcomes and suggest future research.

Modeling denitrification in terrestrial and aquatic ecosystems at regional scales.

Quantifying where, when, and how much denitrification occurs on the basis of measurements alone remains particularly vexing at virtually all spatial scales. As a result, models have become essential tools for integrating current understanding of the processes that control denitrification with measurements of rate-controlling properties so that the permanent losses of N within landscapes can be quantified at watershed and regional scales. In this paper, we describe commonly used approaches for modeling denitrification and N cycling processes in terrestrial and aquatic ecosystems based on selected examples from the literature. We highlight future needs for developing complementary measurements and models of denitrification. Most of the approaches described here do not explicitly simulate microbial dynamics, but make predictions by representing the environmental conditions where denitrification is expected to occur, based on conceptualizations of the N cycle and empirical data from field and laboratory investigations of the dominant process controls. Models of denitrification in terrestrial ecosystems include generally similar rate-controlling variables, but vary in their complexity of the descriptions of natural and human-related properties of the landscape, reflecting a range of scientific and management perspectives. Models of denitrification in aquatic ecosystems range in complexity from highly detailed mechanistic simulations of the N cycle to simpler source-transport models of aggregate N removal processes estimated with empirical functions, though all estimate aquatic N removal using first-order reaction rate or mass-transfer rate expressions. Both the terrestrial and aquatic modeling approaches considered here generally indicate that denitrification is an important and highly substantial component of the N cycle over large spatial scales. However, the uncertainties of model predictions are large. Future progress will be linked to advances in field measurements, spatial databases, and model structures.

Identification of HLA-DRB1*1501-restricted T-cell epitopes from prostate-specific antigen.

The development of immunotherapy for prostate cancer based on the induction of autoimmunity to prostate tissue is very attractive because prostate is not a vital organ beyond the reproductive years. CD4 T cells play an important role in the development of antitumor immune responses, yet the identification of naturally processed MHC Class II-restricted epitopes derived from prostate differentiation antigens has not been described. To facilitate the search for prostate-specific antigen (PSA)-derived MHC class II-restricted peptides, we immunized mice transgenic for HLA-DRB1*1501 with human PSA and showed a robust dose-dependent immune response to the antigen. Screening a library of overlapping 20-mer peptides that span the entire PSA sequence identified two 20-mer peptides, PSA(171-190) and PSA(221-240), which were responsible for this reactivity. Immunization of DR2b transgenic mice with these peptides induced specific responses to the peptide and whole PSA. Identified peptides were used to stimulate CD4 T cells from HLA-DRB1*1501+ patients with a rare condition, granulomatous prostatitis, and who seem to have a preexisting immune response directed against the prostate gland. We previously showed a linkage of granulomatous prostatitis to HLA-DRB1*1501, suggesting that this disease may have an autoimmune etiology. Peptide-specific CD4 T-cell lines were generated from the peripheral blood of these patients as well as one patient with prostate cancer. These lines also recognized whole, processed PSA in the context of HLA-DRB1*1501. This study will be instrumental in understanding the interaction between circulating self-reactive T cells, organ-specific autoimmunity, and antitumor immune response. The use of these peptides for the immunotherapy of prostate cancer is under investigation.

An Immune-Inflammation Gene Expression Signature in Prostate Tumors of Smokers.

Smokers develop metastatic prostate cancer more frequently than nonsmokers, suggesting that a tobacco-derived factor is driving metastatic progression. To identify smoking-induced alterations in human prostate cancer, we analyzed gene and protein expression patterns in tumors collected from current, past, and never smokers. By this route, we elucidated a distinct pattern of molecular alterations characterized by an immune and inflammation signature in tumors from current smokers that were either attenuated or absent in past and never smokers. Specifically, this signature included elevated immunoglobulin expression by tumor-infiltrating B cells, NF-κB activation, and increased chemokine expression. In an alternate approach to characterize smoking-induced oncogenic alterations, we also explored the effects of nicotine in human prostate cancer cells and prostate cancer-prone TRAMP mice. These investigations showed that nicotine increased glutamine consumption and invasiveness of cancer cells in vitro and accelerated metastatic progression in tumor-bearing TRAMP mice. Overall, our findings suggest that nicotine is sufficient to induce a phenotype resembling the epidemiology of smoking-associated prostate cancer progression, illuminating a novel candidate driver underlying metastatic prostate cancer in current smokers.