Immunogenicity of human hepatitis B virus P-gene derived proteins

The frequency and specificity of antibodies to P-gene encoded proteins of human hepatitis B virus was tested in sera of acute and chronically infected patients with and without hepatocellular carcinoma (HCC). For antibody detection an immunoprecipitation gel assay was performed with radioactively labeled polypeptides produced by in vitro translation of RNA of different P-gene regions. Thus, five antigenic regions were identified. All anti-P antibody positive sera reacted with carboxy-terminal P-poly-peptides, a subset with polypeptides of the amino-terminal and middle region, and none reacted with P-protein derived from the most sequence variable region. Anti-P antibodies were detected at very high frequency in sera of acute (73%) and chronically infected patients without HCC (87%), but less often in HCC patients (27%). These data indirectly demonstrate the expression of most hepatitis B virus P-gene sequences and the immunogenicity of P-proteins in vivo. Moreover, they establish hepatitis B virus anti-P-antibodies as a frequent serologic marker of infection and identify the carboxy-terminal region of the P-protein(s) as immunodominant.     

Denitrifying bioreactors—An approach for reducing nitrate loads to receiving waters

Low-cost and simple technologies are needed to reduce watershed export of excess nitrogen to sensitive aquatic ecosystems. Denitrifying bioreactors are an approach where solid carbon substrates are added into the flow path of contaminated water. These carbon (C) substrates (often fragmented wood-products) act as a C and energy source to support denitrification; the conversion of nitrate (NO₃^?) to nitrogen gases. Here, we summarize the different designs of denitrifying bioreactors that use a solid C substrate, their hydrological connections, effectiveness, and factors that limit their performance. The main denitrifying bioreactors are: denitrification walls (intercepting shallow groundwater), denitrifying beds (intercepting concentrated discharges) and denitrifying layers (intercepting soil leachate). Both denitrifcation walls and beds have proven successful in appropriate field settings with NO₃^? removal rates generally ranging from 0.01 to 3.6 g N m^?3 day^?1 for walls and 2–22 g N m^?3 day^?1 for beds, with the lower rates often associated with nitrate-limitations. Nitrate removal is also limited by the rate of C supply from degrading substrate and removal is operationally zero-order with respect to NO₃^? concentration primarily because the inputs of NO₃^? into studied bioreactors have been generally high. In bioreactors where NO₃^? is not fully depleted, removal rates generally increase with increasing temperature. Nitrate removal has been supported for up to 15 years without further maintenance or C supplementation because wood chips degrade sufficiently slowly under anoxic conditions. There have been few field-based comparisons of alternative C substrates to increase NO₃^? removal rates but laboratory trials suggest that some alternatives could support greater rates of NO₃^? removal (e.g., corn cobs and wheat straw). Denitrifying bioreactors may have a number of adverse effects, such as production of nitrous oxide and leaching of dissolved organic matter (usually only for the first few months after construction and start-up). The relatively small amount of field data suggests that these problems can be adequately managed or minimized. An initial cost/benefit analysis demonstrates that denitrifying bioreactors are cost effective and complementary to other agricultural management practices aimed at decreasing nitrogen loads to surface waters. We conclude with recommendations for further research to enhance performance of denitrifying bioreactors.     

Studies on insulin action. V. Structural requirements of primers for subsequent accumulation of D-glucose at 0 degrees C in insulinized frog muscles.

Systematic analysis was made of structural requirements for possible priming action of D-glucose and 40 related compounds in the presence of insulin to enhance subsequent labeled D-glucose uptake at 0 degrees C. It was concluded that a major portion if not all of the H-bonding groups on the D-glucose molecules are involved although their relative importance varies. Free OH and H on C-1, and upward orientation of OH and downward orientation of H on C-3, are the most important. Orientation of OH, H, and CH2OH on C-2, C-4, and C-5 are also important, but their perturbations are not nearly as detrimental to the priming action as those on C-1 and C-3.     

Prerequisites for the pharmaceutical industry to develop and commercialise helminths and helminth-derived product therapy

During the past 10 years, immunologists, epidemiologists and parasitologists have made many new exciting discoveries in the field of helminth-mediated immune regulation. In addition, many animal experiments have shown that certain helminths or products derived from helminths can protect mice from developing allergic or autoimmune disease. Some clinical trials utilising Trichuris suis or Necator americanus for the treatment of allergic disorders and inflammatory bowel disease have been conducted. The outcomes of these trials suggest that they may be used to treat these disorders. However, to date no helminth therapy is routinely being applied to patients and no helminth-derived product therapy has been developed. In order to bring new drugs to the market and shoulder the enormous costs involved in developing such therapies, pharmaceutical companies need to be involved. However, currently the resources from the pharmaceutical industry devoted to this concept are relatively small and there are good reasons why the industry may have been reluctant to invest in developing these types of therapies. In this review article, the hurdles that must be overcome before the pharmaceutical industry might invest in these novel therapies are outlined.     

Refining Estimates of Bird Collision and Electrocution Mortality at Power Lines in the United States

Collisions and electrocutions at power lines are thought to kill large numbers of birds in the United States annually. However, existing estimates of mortality are either speculative (for electrocution) or based on extrapolation of results from one study to all U.S. power lines (for collision). Because national-scale estimates of mortality and comparisons among threats are likely to be used for prioritizing policy and management strategies and for identifying major research needs, these estimates should be based on systematic and transparent assessment of rigorously collected data. We conducted a quantitative review that incorporated data from 14 studies meeting our inclusion criteria to estimate that between 12 and 64 million birds are killed each year at U.S. power lines, with between 8 and 57 million birds killed by collision and between 0.9 and 11.6 million birds killed by electrocution. Sensitivity analyses indicate that the majority of uncertainty in our estimates arises from variation in mortality rates across studies; this variation is due in part to the small sample of rigorously conducted studies that can be used to estimate mortality. Little information is available to quantify species-specific vulnerability to mortality at power lines; the available literature over-represents particular bird groups and habitats, and most studies only sample and present data for one or a few species. Furthermore, additional research is needed to clarify whether, to what degree, and in what regions populations of different bird species are affected by power line-related mortality. Nonetheless, our data-driven analysis suggests that the amount of bird mortality at U.S. power lines is substantial and that conservation management and policy is necessary to reduce this mortality.