Toxicity Testing in the 21st Century: Defining New Risk Assessment Approaches Based on Perturbation of Intracellular Toxicity Pathways

The approaches to quantitatively assessing the health risks of chemical exposure have not changed appreciably in the past 50 to 80 years, the focus remaining on high-dose studies that measure adverse outcomes in homogeneous animal populations. This expensive, low-throughput approach relies on conservative extrapolations to relate animal studies to much lower-dose human exposures and is of questionable relevance to predicting risks to humans at their typical low exposures. It makes little use of a mechanistic understanding of the mode of action by which chemicals perturb biological processes in human cells and tissues. An alternative vision, proposed by the U.S. National Research Council (NRC) report Toxicity Testing in the 21st Century: A Vision and a Strategy, called for moving away from traditional high-dose animal studies to an approach based on perturbation of cellular responses using well-designed in vitro assays. Central to this vision are (a) “toxicity pathways” (the innate cellular pathways that may be perturbed by chemicals) and (b) the determination of chemical concentration ranges where those perturbations are likely to be excessive, thereby leading to adverse health effects if present for a prolonged duration in an intact organism. In this paper we briefly review the original NRC report and responses to that report over the past 3 years, and discuss how the change in testing might be achieved in the U.S. and in the European Union (EU). EU initiatives in developing alternatives to animal testing of cosmetic ingredients have run very much in parallel with the NRC report. Moving from current practice to the NRC vision would require using prototype toxicity pathways to develop case studies showing the new vision in action. In this vein, we also discuss how the proposed strategy for toxicity testing might be applied to the toxicity pathways associated with DNA damage and repair

HIV Prevention in High-Risk Women in South Africa: Condom Use and the Need for Change

INTRODUCTION: Young women are at disproportionate risk of HIV infection in South Africa. Understanding risk behaviors and factors associated with ability to negotiate safe sex and condom use is likely to be key in curbing the spread of HIV. Traditionally prevention efforts have focused on creating behavioral changes by increasing knowledge about HIV/AIDS. METHODS: This was a cross-sectional analysis from a prospective observational cohort study of 245 women at a high-risk of HIV infection in KwaZulu-Natal, South Africa. RESULTS: Participants demonstrated a high level of HIV/AIDS knowledge. Overall, 60.3% of participants reported condom use. Reported condom use at last sexual encounter varied slightly by partner type (57.0% with steady versus 64.4% with casual partners), and self-perceived ability to choose to use a condom was significantly lower with steady partners compared to casual partners (p<0.01). In multivariate analysis, women who had high school education were more likely to use condoms at their last sex encounter compared to those with only primary school education (RR of 1.36 (95% Confidence Interval (CI) 1.06-1.75) and 1.46 (95% CI 1.13-1.88) for grades 8-10 and 11-12, respectively). Those who used condoms as a contraceptive method were twice as likely to use condoms compared to women who did not report using them as a contraceptive method. Greater perceived ability to choose to use condoms was associated with higher self-reported condom use at last encounter, irrespective of partner type (RR = 2.65 (95% CI 2.15-32.5). DISCUSSION: Self-perceived ability to use condoms, level of formal education and condom use as a contraceptive were all significantly associated with self-reported condom use at last sexual encounter. These findings suggest that that gender inequality and access to formal education, as opposed to lack of HIV/AIDS knowledge, prevent safer sexual practices in South Africa

Evolution of Parallel Spindles Like genes in plants and highlight of unique domain architecture#

<p>Abstract</p> <p>Background</p> <p>Polyploidy has long been recognized as playing an important role in plant evolution. In flowering plants, the major route of polyploidization is suggested to be sexual through gametes with somatic chromosome number (2<it>n</it>). <it>Parallel Spindle1 </it>gene in <it>Arabidopsis thaliana </it>(<it>AtPS1</it>) was recently demonstrated to control spindle orientation in the 2nd division of meiosis and, when mutated, to induce 2<it>n </it>pollen. Interestingly, <it>AtPS1 </it>encodes a protein with a FHA domain and PINc domain putatively involved in RNA decay (i.e. Nonsense Mediated mRNA Decay). In potato, 2<it>n </it>pollen depending on parallel spindles was described long time ago but the responsible gene has never been isolated. The knowledge derived from <it>AtPS1 </it>as well as the availability of genome sequences makes it possible to isolate potato <it>PSLike </it>(<it>PSL</it>) and to highlight the evolution of <it>PSL </it>family in plants.</p> <p>Results</p> <p>Our work leading to the first characterization of <it>PSLs </it>in potato showed a greater <it>PSL </it>complexity in this species respect to <it>Arabidopsis thaliana</it>. Indeed, a genomic <it>PSL </it>locus and seven cDNAs affected by alternative splicing have been cloned. In addition, the occurrence of at least two other <it>PSL </it>loci in potato was suggested by the sequence comparison of alternatively spliced transcripts.</p> <p>Phylogenetic analysis on 20 <it>Viridaeplantae </it>showed the wide distribution of <it>PSLs </it>throughout the species and the occurrence of multiple copies only in potato and soybean.</p> <p>The analysis of PSL^FHAand PSL^PINcdomains evidenced that, in terms of secondary structure, a major degree of variability occurred in PINc domain respect to FHA. In terms of specific active sites, both domains showed diversification among plant species that could be related to a functional diversification among <it>PSL </it>genes. In addition, some specific active sites were strongly conserved among plants as supported by sequence alignment and by evidence of negative selection evaluated as difference between non-synonymous and synonymous mutations.</p> <p>Conclusions</p> <p>In this study, we highlight the existence of PSLs throughout <it>Viridaeplantae</it>, from mosses to higher plants. We provide evidence that <it>PSLs </it>occur mostly as singleton in the analyzed genomes except in soybean and potato both characterized by a recent whole genome duplication event. In potato, we suggest the candidate <it>PSL </it>gene having a role in 2<it>n </it>pollen that should be deeply investigated.</p> <p>We provide useful insight into evolutionary conservation of FHA and PINc domains throughout plant PSLs which suggest a fundamental role of these domains for PSL function.</p

Expression of costimulatory molecules in the bovine corpus luteum

BACKGROUND: Bovine luteal parenchymal cells express class II major histocompatibility complex (MHC) molecules and stimulate class II MHC-dependent activation of T cells in vitro. The ability of a class II MHC-expressing cell type to elicit a response from T cells in vivo is also dependent on expression of costimulatory molecules by the antigen presenting cell and delivery of a costimulatory signal to the T cell. Whether bovine luteal parenchymal cells express costimulatory molecules and can deliver the costimulatory signal is currently unknown. METHODS: Bovine luteal tissue was collected during the early (day 5; day of estrus = day 0), mid (day 11–12), or late (day 18) luteal phase of the estrous cycle, and at 0, 0.5, 1, 4, 12 or 24 hours following administration of PGF2alpha to cows on day 10 of the estrous cycle. Northern analysis was used to measure CD80 or CD86 mRNA concentrations in luteal tissue samples. Mixed luteal parenchymal cell cultures and purified luteal endothelial cell cultures were prepared, and real-time RT-PCR was used to examine the presence of CD80 and CD86 mRNA in each culture type. Monoclonal antibodies to CD80 and CD86 were added to a mixed luteal parenchymal cell-T cell co-culture in vitro T cell proliferation assay to assess the functional significance of costimulatory molecules on activation of T lymphocytes by luteal parenchymal cells. RESULTS: Northern analysis revealed CD80 and CD86 mRNAs in luteal tissue, with greatest steady-state concentrations at midcycle. CD80 and CD86 mRNAs were detected in mixed luteal parenchymal cell cultures, but only slight amounts of CD80 (and not CD86) mRNA were detected in cultures of luteal endothelial cells. Luteinizing hormone, PGF2alpha and TNF-alpha were without effect on concentrations of CD80 or CD86 mRNA in mixed luteal parenchymal cells cultures. Anti-CD80 or anti-CD86 monoclonal antibodies inhibited T cell proliferation in the in vitro T cell proliferation assay. CONCLUSION: It can be concluded from this study that parenchymal cells within the bovine CL express functional costimulatory molecules that facilitate interactions between with T cells, and these components of the antigen presentation pathway are expressed maximally in the midcycle CL

Granulocyte-colony stimulating factor for stroke treatment: mechanisms of action and efficacy in preclinical studies

G-CSF is widely employed for the treatment of chemotherapy-induced neutropenia. Recently, neuroprotective effects of G-CSF in animal stroke models were discovered including infarct size reduction and enhancement of functional recovery. The underlying mechanisms of action of G-CSF in ischemia appear to be a direct anti-apoptotic activity in neurons and a neurogenesis inducing capacity. Additional effects may be based on the stimulation of new blood-vessel formation, the stimulation of immunocompetence and -modulation as well as on bone marrow mobilization. In addition to a discussion of these mechanisms, we will review the available preclinical studies and analyze their impact on the overall efficacy of G-CSF in experimental stroke

Mitoxantrone Induces Natural Killer Cell Maturation in Patients with Secondary Progressive Multiple Sclerosis

Mitoxantrone is one of the few drugs approved for the treatment of progressive multiple sclerosis (MS). However, the prolonged use of this potent immunosuppressive agent is limited by the appearance of severe side effects. Apart from its general cytotoxic effect, the mode of action of mitoxantrone on the immune system is poorly understood. Thus, to develop safe therapeutic approaches for patients with progressive MS, it is essential to elucidate how mitoxantrone exerts it benefits. Accordingly, we initiated a prospective single-arm open-label study with 19 secondary progressive MS patients. We investigated long-term effects of mitoxantrone on patient peripheral immune subsets using flow cytometry. While we corroborate that mitoxantrone persistently suppresses B cells in vivo, we show for the first time that treatment led to an enrichment of neutrophils and immunomodulatory CD8low T cells. Moreover, sustained mitoxantrone applications promoted not only persistent NK cell enrichment but also NK cell maturation. Importantly, this mitoxantrone-induced NK cell maturation was seen only in patients that showed a clinical response to treatment. Our data emphasize the complex immunomodulatory role of mitoxantrone, which may account for its benefit in MS. In particular, these results highlight the contribution of NK cells to mitoxantrone efficacy in progressive MS

Systematic review on quality control for drug management programs: Is quality reported in the literature?

<p>Abstract</p> <p>Background</p> <p>Maintaining quality of care while managing limited healthcare resources is an ongoing challenge in healthcare. The objective of this study was to evaluate how the impact of drug management programs is reported in the literature and to identify potentially existing quality standards.</p> <p>Methods</p> <p>This analysis relates to the published research on the impact of drug management on economic, clinical, or humanistic outcomes in managed care, indemnity insurance, VA, or Medicaid in the USA published between 1996 and 2007. Included articles were systematically analyzed for study objective, study endpoints, and drug management type. They were further categorized by drug management tool, primary objective, and study endpoints.</p> <p>Results</p> <p>None of the 76 included publications assessed the overall quality of drug management tools. The impact of 9 different drug management tools used alone or in combination was studied in pharmacy claims, medical claims, electronic medical records or survey data from either patient, plan or provider perspective using an average of 2.1 of 11 possible endpoints. A total of 68% of the studies reported the impact on plan focused endpoints, while the clinical, the patient or the provider perspective were studied to a much lower degree (45%, 42% and 12% of the studies). Health outcomes were only accounted for in 9.2% of the studies.</p> <p>Conclusion</p> <p>Comprehensive assessment of quality considering plan, patient and clinical outcomes is not yet applied. There is no defined quality standard. Benchmarks including health outcomes should be determined and used to improve the overall clinical and economic effectiveness of drug management programs.</p

Autism Symptoms and Internalizing Psychopathology in Girls and Boys with Autism Spectrum Disorders

Findings regarding phenotypic differences between boys and girls with ASD are mixed. We compared autism and internalizing symptoms in a sample of 8-18 year-old girls (n = 20) and boys (n = 20) with ASD and typically developing (TYP) girls (n = 19) and boys (n = 17). Girls with ASD were more impaired than TYP girls but did not differ from boys with ASD in autism symptoms. In adolescence, girls with ASD had higher internalizing symptoms than boys with ASD and TYP girls, and higher symptoms of depression than TYP girls. Girls ages 8-18 with ASD resemble boys with ASD and not TYP girls, and appear to be at increased risk for affective symptoms in the teen years

Interventions designed to improve the quality and efficiency of medication use in managed care: A critical review of the literature – 2001–2007

<p>Abstract</p> <p>Background</p> <p>Managed care organizations use a variety of strategies to reduce the cost and improve the quality of medication use. The effectiveness of such policies is not well understood. The objective of this research was to update a previous systematic review of interventions, published between 1966 and 2001, to improve the quality and efficiency of medication use in the US managed care setting.</p> <p>Methods</p> <p>We searched MEDLINE and EMBASE for publications from July 2001 to January 2007 describing interventions targeting drug use conducted in the US managed care setting. We categorized studies by intervention type and adequacy of research design using commonly accepted criteria. We summarized the outcomes of well-controlled strategies and documented the significance and magnitude of effects for key study outcomes.</p> <p>Results</p> <p>We identified 164 papers published during the six-year period. Predominant strategies were: educational interventions (n = 20, including dissemination of educational materials, and group or one-to-one educational outreach); monitoring and feedback (n = 22, including audit/feedback and computerized monitoring); formulary interventions (n = 66, including tiered formulary and patient copayment); collaborative care involving pharmacists (n = 15); and disease management with pharmacotherapy as a primary focus (n = 41, including care for depression, asthma, and peptic ulcer disease). Overall, 51 studies met minimum criteria for methodological adequacy. Effective interventions included one-to-one academic detailing, computerized alerts and reminders, pharmacist-led collaborative care, and multifaceted disease management. Further, changes in formulary tier-design and related increases in copayments were associated with reductions in medication use and increased out-of-pocket spending by patients. The dissemination of educational materials alone had little or no impact, while the impact of group education was inconclusive.</p> <p>Conclusion</p> <p>There is good evidence for the effectiveness of several strategies in changing drug use in the managed care environment. However, little is known about the cost-effectiveness of these interventions. Computerized alerts showed promise in improving short-term outcomes but little is known about longer-term outcomes. Few well-designed, published studies have assessed the potential negative clinical effects of formulary-related interventions despite their widespread use. However, some evidence suggests increases in cost sharing reduce access to essential medicines for chronic illness.</p