Radiative Capture of Tensor Polarized Deuterons on Hydrogen Isotopes

This research was sponsored by the National Science Foundation Grant NSF PHY 87-1440

A comparative analysis of phenylpropanoid metabolism, N utilization, and carbon partitioning in fast- and slow-growing Populus hybrid clones

The biosynthetic costs of phenylpropanoid-derived condensed tannins (CTs) and phenolic glycosides (PGs) are substantial. However, despite reports of negative correlations between leaf phenolic content and growth of Populus, it remains unclear whether or how foliar biosynthesis of CT/PG interferes with tree growth. A comparison was made of carbon partitioning and N content in developmentally staged leaves, stems, and roots of two closely related Populus hybrid genotypes. The genotypes were selected as two of the most phytochemically divergent from a series of seven previously analysed clones that exhibit a range of height growth rates and foliar amino acid, CT, and PG concentrations. The objective was to analyse the relationship between leaf phenolic content and plant growth, using whole-plant carbon partitioning and N distribution data from the two divergent clones. Total N as a percentage of tissue dry mass was comparatively low, and CT and PG accrual comparatively high in leaves of the slow-growing clone. Phenylpropanoid accrual and N content were comparatively high in stems of the slow-growing clone. Carbon partitioning within phenylpropanoid and carbohydrate networks in developing stems differed sharply between clones. The results did not support the idea that foliar production of phenylpropanoid defence chemicals was the primary cause of reduced plant growth in the slow-growing clone. The findings are discussed in the context of metabolic mechanism(s) which may contribute to reduced N delivery from roots to leaves, thereby compromising tree growth and promoting leaf phenolic accrual in the slow-growing clone

Effect of 2‐methoxyestradiol on mammary tumor initiation and progression

Abstract Background The anti‐cancer agent 2‐methoxyestradiol (2‐ME) has been shown to have anti‐proliferative and anti‐angiogenic properties. Previously, the effect of 2‐ME on early‐ and late‐stage breast cancer (BC) was investigated in vivo using a transgenic mouse model (FVB/N‐Tg(MMTV‐PyVT)) of spontaneous mammary carcinoma. Anti‐tumor effects were observed in late‐stage BC with no effect on early‐stage BC. Given the contrasting results obtained from the different BC stages, we have now investigated the effect of 2‐ME when administered before the appearance of palpable tumors. Methods Each mouse received 100 mg/kg 2‐ME on day 30 after birth, twice per week for 28 days, while control mice received vehicle only. Animals were terminated on day 59. Lung and mammary tissue were obtained for immunohistochemical analysis of CD163 and CD3 expression, and histological examination was performed to analyze tumor necrosis. Additionally, blood samples were collected to measure plasma cytokine levels. Results 2‐ME increased tumor mass when compared to the untreated animals (p = .0139). The pro‐tumorigenic activity of 2‐ME was accompanied by lower CD3+ T‐cell numbers in the tumor microenvironment (TME) and high levels of the pro‐inflammatory cytokine interleukin (IL)‐1β. Conversely, 2‐ME‐treatment resulted in fewer CD163+ cells detectable in the TME, increased levels of tumor necrosis, increased IL‐10 plasma levels, and low IL‐6 and IL‐27 plasma levels. Conclusion Taken together, these findings suggest that 2‐ME promotes early‐stage BC development

Preventing tuberculosis with community‐based care in an HIV‐endemic setting: a modelling analysis

Abstract Introduction Antiretroviral therapy (ART) and tuberculosis preventive treatment (TPT) both prevent tuberculosis (TB) disease and deaths among people living with HIV. Differentiated care models, including community‐based care, can increase the uptake of ART and TPT to prevent TB in settings with a high burden of HIV‐associated TB, particularly among men. Methods We developed a gender‐stratified dynamic model of TB and HIV transmission and disease progression among 100,000 adults ages 15−59 in KwaZulu‐Natal, South Africa. We drew model parameters from a community‐based ART initiation and resupply trial in sub‐Saharan Africa (Delivery Optimization for Antiretroviral Therapy, DO ART) and other scientific literature. We simulated the impacts of community‐based ART and TPT care programmes during 2018−2027, assuming that community‐based ART and TPT care were scaled up to similar levels as in the DO ART trial (i.e. ART coverage increasing from 49% to 82% among men and from 69% to 83% among women) and sustained for 10 years. We projected the number of TB cases, deaths and disability‐adjusted life years (DALYs) averted relative to standard, clinic‐based care. We calculated programme costs and incremental cost‐effectiveness ratios from the provider perspective. Results If community‐based ART care could be implemented with similar effectiveness to the DO ART trial, increased ART coverage could reduce TB incidence by 27.0% (range 21.3%−34.1%) and TB mortality by 34.6% (range 24.8%–42.2%) after 10 years. Increasing both ART and TPT uptake through community‐based ART with TPT care could reduce TB incidence by 29.7% (range 23.9%−36.0%) and TB mortality by 36.0% (range 26.9%−43.8%). Community‐based ART with TPT care reduced gender disparities in TB mortality rates, with a projected 54 more deaths annually among men than women (range 11–103) after 10 years of community‐based care versus 109 (range 41–182) in standard care. Over 10 years, the mean cost per DALY averted by community‐based ART with TPT care was $846 USD (range$709–$1012). Conclusions By substantially increasing coverage of ART and TPT, community‐based care for people living with HIV could reduce TB incidence and mortality in settings with high burdens of HIV‐associated TB and reduce TB gender disparities

An Analysis of Pharmaceutical Experience with Decades of Rat Carcinogenicity Testing: Support for a Proposal to Modify Current Regulatory Guidelines

Data collected from 182 marketed and nonmarketed pharmaceuticals demonstrate that there is little value gained in conducting a rat two-year carcinogenicity study for compounds that lack: (1) histopathologic risk factors for rat neoplasia in chronic toxicology studies, (2) evidence of hormonal perturbation, and (3) positive genetic toxicology results. Using a single positive result among these three criteria as a test for outcome in the two-year study, fifty-two of sixty-six rat tumorigens were correctly identified, yielding 79% test sensitivity. When all three criteria were negative, sixty-two of seventy-six pharmaceuticals (82%) were correctly predicted to be rat noncarcinogens. The fourteen rat false negatives had two-year study findings of questionable human relevance. Applying these criteria to eighty-six additional chemicals identified by the International Agency for Research on Cancer as likely human carcinogens and to drugs withdrawn from the market for carcinogenicity concerns confirmed their sensitivity for predicting rat carcinogenicity outcome. These analyses support a proposal to refine regulatory criteria for conducting a two-year rat study to be based on assessment of histopathologic findings from a rat six-month study, evidence of hormonal perturbation, genetic toxicology results, and the findings of a six-month transgenic mouse carcinogenicity study. This proposed decision paradigm has the potential to eliminate over 40% of rat two-year testing on new pharmaceuticals without compromise to patient safet