Prophylactic and Therapeutic Efficacy of Avian Antibodies Against Influenza Virus H5N1 and H1N1 in Mice

Background

Pandemic influenza poses a serious threat to global health and the world economy. While vaccines are currently under development, passive immunization could offer an alternative strategy to prevent and treat influenza virus infection. Attempts to develop monoclonal antibodies (mAbs) have been made. However, passive immunization based on mAbs may require a cocktail of mAbs with broader specificity in order to provide full protection since mAbs are generally specific for single epitopes. Chicken immunoglobulins (IgY) found in egg yolk have been used mainly for treatment of infectious diseases of the gastrointestinal tract. Because the recent epidemic of highly pathogenic avian influenza virus (HPAIV) strain H5N1 has resulted in serious economic losses to the poultry industry, many countries including Vietnam have introduced mass vaccination of poultry with H5N1 virus vaccines. We reasoned that IgY from consumable eggs available in supermarkets in Vietnam could provide protection against infections with HPAIV H5N1.

Methods and Findings

We found that H5N1-specific IgY that are prepared from eggs available in supermarkets in Vietnam by a rapid and simple water dilution method cross-protect against infections with HPAIV H5N1 and related H5N2 strains in mice. When administered intranasally before or after lethal infection, the IgY prevent the infection or significantly reduce viral replication resulting in complete recovery from the disease, respectively. We further generated H1N1 virus-specific IgY by immunization of hens with inactivated H1N1 A/PR/8/34 as a model virus for the current pandemic H1N1/09 and found that such H1N1-specific IgY protect mice from lethal influenza virus infection.

Conclusions

The findings suggest that readily available H5N1-specific IgY offer an enormous source of valuable biological material to combat a potential H5N1 pandemic. In addition, our study provides a proof-of-concept for the approach using virus-specific IgY as affordable, safe, and effective alternative for the control of influenza outbreaks, including the current H1N1 pandemic.     

The association between exposure determined by radiofrequency personal exposimeters and human exposure: A simulation study

The selection of an adequate exposure assessment approach is imperative for the quality of epidemiological studies. The use of personal exposimeters turned out to be a reasonable approach to determine exposure profiles, however, certain limitations regarding the absolute values delivered by the devices have to be considered. Apart from the limited dynamic range, it has to be taken into account that these devices give only an approximation of the exposure due to the influence of the body of the person carrying the exposimeter, the receiver characteristics of the exposimeter, as well as the dependence of the measured value on frequency band, channel, slot configuration, and communication traffic. In this study, the relationship between the field strength measured close to the human body at the location of the exposimeter and the exposure, that is, the field strength at the location of the human body without the human body present, is investigated by numerical means using the Visible Human model as an anatomical phantom. Two different scenarios were chosen: (1) For FM, GSM, and UMTS an urban outdoor scenario was examined that included a transmitting antenna mounted on the roof of one of four buildings at a street crossing, (2) For WLAN an indoor scenario was investigated. For GSM the average degree of underestimation by the exposimeter (relation of the average field levels at the location of the exposimeter to the field level averaged over the volume of the human body without the body present) was 0.76, and for UMTS 0.87; for FM no underestimation was found, the ratio was 1. In the case of WLAN the degree of underestimation was more pronounced, the ratio was 0.64. This study clearly suggests that a careful evaluation of correction factors for different scenarios is needed prior to the definition of the study protocol. It has to be noted that the reference scenario used in this study does not allow for final conclusions on general correction factors. Bioelectromagnetics 31:535–545, 2010. © 2010 Wiley‐Liss, Inc.     

Vegetative growth and frost hardiness of cloudberry (Rubus chamaemorus) as affected by temperature and photoperiod

The effect of photoperiod and temperature on growth and induction and development of frost hardiness in cloudberry ( Rubus chamaemorus L.) was examined in two experiments. The photoperiods were 8, 12 or 24 h and the temperatures were 18, 15, 12, 9, 4, 3, –3 or –4°C depending on the experiment. The level of hardiness was expressed as LT₆₆ or LT₅₀ (the lethal temperature for 66 or 50% of the plant material) for percentage of bud break and for the degree of coloring by triphenyltetrazolium chloride for rhizomes. The vegetative growth was clearly affected by daylength; petiole elongation, leaf growth, shoot dry weight and number of shoots per plant were all reduced under short days compared with long days. However, the photoperiod had no significant effect on hardening of buds or rhizomes. Hardening increased with successively decreasing temperatures. To get the maximum hardiness, plants had to be exposed to freezing temperatures.     

Lexical Encoding Sequences and Language Change: Color Terminology Systems

Lexical reconstructions of Proto-Polynesian (Branstetter 1977), Proto-Miwok (Callaghan 1979), and Proto-Mayan (Fox 1977; Kaufman 1964, 1969) basic color term vocabularies are presented and compared. Although these reconstructed systems accord with the well-known Berlin and Kay (1969) color encoding sequence, they all contain a subtle distortion They generally are as large as color term systems found in contemporary daughter languages. Considering the additive nature of the color encoding sequence, these reconstructions are unlikely. Comparative linguistic evidence is presented suggesting that all three systems are over-reconstructed. Encoding sequences, then, prove to be instruments of considerable usefulness to add to the traditional tool kit of historical linguistics . [cognitive anthropology, color classification, language change, language universale, Mayan languages, Miwok languages, Polynesian languages]     

Xylanolytic Activity of Clostridium acetobutylicum

Of 20 strains of Clostridium spp. screened, 17 hydrolyzed larch wood xylan. Two strains of Clostridium acetobutylicum, NRRL B527 and ATCC 824, hydrolyzed xylan but failed to grow on solid media with larch xylan as the sole carbon source; however, strain ATCC 824 was subsequently found to grow on xylan under specified conditions in a chemostat. These two strains possessed cellulolytic activity and were therefore selected for further studies. In cellobiose-limited continuous cultures, strain NRRL B527 produced maximum xylanase activity at pH 5.2. Strain ATCC 824 produced higher xylanase, xylopyranosidase, and arabinofuranosidase activities in chemostat culture with xylose than with any other soluble carbon source as the limiting nutrient. The activities of these enzymes were markedly reduced when the cells were grown in the presence of excess glucose. The xylanase showed maximum activity at pH 5.8 to 6.0 and 65°C. The enzyme was stable on the alkaline side of pH 5.2 but was unstable below this pH value. The extracellular xylanolytic activity from strain ATCC 824 hydrolyzed 12% of the larch wood xylan during a 24-h incubation period, yielding xylose, xylobiose, and xylotriose as the major hydrolysis products. Strain ATCC 824, after being induced to grow in batch culture in xylan medium supplemented with a low concentration of xylose, failed to grow reproducibly in unsupplemented xylan medium. A mutant obtained by mutagenesis with ethyl methanesulfonate was able to grow reproducibly in batch culture on xylan. Both the parent strain and the mutant were able to grow with xylan as the sole source of carbohydrate in continuous culture with the pH maintained at either 5.2 or 6.0. Under these conditions, the cells utilized approximately 50% of the xylan.