Comparative studies on the influence of radioprotectors and amino acids on the chromosome-damaging activity of 8-hydroxyquinoline sulfate in human lymphocytes in vitro

The influence of the radioprotectors cystaamine and aminoethylisothiouronium (AET) as well as the amino acids l-cysteine, l-alanine, l-arginine, l-asparagine, l-glutamic acid, l-histidine and l-methionine on the cytogenetic action of 8-hydroxyquinoline sulphate (8-HCHS) was tested in human lymphocyte cultures in vitro. An excess of l-cysteine, cysteamine, and l-asparagine, when added to the cultures simulataneously with 8-HCHS, distinctly reduced the chromosome-damaging effect of this agent. l-Glutamic acid and AET exerted a protective activity to a lesser extent. l-Methionine only displayed some effect in reducing the relatively rare isochromatid aberrations induced by 8-HCHS. The other amino acids had no effect on the chromosome-damaging action of this substance.The dose dependence of the protective activity as well as the degree of effectivity and the spectrum of action of the different protectors are compared. The possible mechanisms of action are discussed.     

G4 DNA replication: I. Origin of synthesis of the viral and complementary DNA strands

The break in the complementary DNA strand of early G4 replicative form II DNA (RFII) and in the viral DNA strand of late RFII DNA was located using two single cleavage restriction enzymes (EcoRI and PstI) and by limited nick translation of the break using DNA polymerase I and ³²P-labelled deoxyribonucleotides followed by digestion with the restriction enzymes HaeIII and HindII. The break in the complementary DNA strand was unique and in HaeIII Z5 close to the EcoRI cleavage site whereas the break in the viral DNA strand was on the other side of the molecule in HaeIII Z2 approxiately 50% away from the EcoRI cleavage site. Distribution of a short ³H pulse in early G4 replicating intermediates that were synthesising both DNA strands at the same time showed that synthesis of the strands started on opposite sides of the molecule and proceeded in opposite convergent directions, suggesting that initiation of synthesis of the two strands was independent and not unified in a single growing fork.     

Crypteins derived from the mouse neuropeptide FF (NPFF)A precursor display NPFF-like effects in nociceptive tests in mice

NPFF precursor, pro-NPFF(A) contains three known bioactive sequences: NPFF (FLFQPQRF-NH(2)), neuropeptide AF (NPAF; AGEGLSSPFWSLAAPQRF-NH(2)) and neuropeptide SF (NPSF; SLAAPQRF-NH(2)). The key-feature of these fragments is their common PQRF-amidated sequence at their C termini. Here, we evaluated the biological activity of two other sequences derived from the mouse NPFF(A) precursor, that does not have PQRF-amidated C-terminus. One peptide was residing between positions 85 and 99 in the mice pro-NPFF(A). This peptide was referred to as neuropeptide SA (NPSA; SAWGSWSKEQLNPQA), assigned due to its flanking amino acids. Another sequence used in the experiments was N-terminal fragment of NPSA, here referred to as neuropeptide SS (NPSS; SAWGSWS). These two peptides, classified as crypteins, were synthesized and tested in the hot-plate and tail immersion tests in mice for their pharmacological activity in morphine-induced antinociception. The effects of both crypteins were compared to NPFF. Our experiments indicated that both crypteins inhibited morphine antinociception and their effects were reversed by RF9, an antagonist of NPFF receptors. These data show that NPSA and NPSS possess NPFF-like anti-opioid activity in these behavioral tests.     

Estimation of Electromagnetic Dosimetric Values from Non-Ionizing Radiofrequency Fields in an Indoor Commercial Airplane Environment

In this article, the impact of topology as well as morphology of a complex indoor environment such as a commercial aircraft in the estimation of dosimetric assessment is presented. By means of an in-house developed deterministic 3D ray-launching code, estimation of electric field amplitude as a function of position for the complete volume of a commercial passenger airplane is obtained. Estimation of electromagnetic field exposure in this environment is challenging, due to the complexity and size of the scenario, as well as to the large metallic content, giving rise to strong multipath components. By performing the calculation with a deterministic technique, the complete scenario can be considered with an optimized balance between accuracy and computational cost. The proposed method can aid in the assessment of electromagnetic dosimetry in the future deployment of embarked wireless systems in commercial aircraft.     

Identification of human IgG1 variant with enhanced FcRn binding and without increased binding to rheumatoid factor autoantibody

Various studies have demonstrated that Fc engineering to enhance neonatal Fc receptor (FcRn) binding is effective for elongating half-life or increasing cellular uptake of IgG. A previous study has shown that a N434H mutation to enhance FcRn binding resulted in increased binding to rheumatoid factor (RF) autoantibody, which is not desirable for therapeutic use in autoimmune disease. In this study, we first showed that all the existing Fc variants with enhanced FcRn binding also show increased RF binding, and then identified specific mutations that could be introduced to those Fc variants to reduce the RF binding. Furthermore, we generated novel Fc variants that do not increase RF binding and show half-lives of 45 d in cynomolgus monkey, which is longer than those of previously reported Fc variants. In addition, we generated novel Fc variants with antigen sweeping activity that do not increase RF binding. We expect that these novel Fc variants will be useful as antibody therapeutics against autoimmune diseases.     

A new pair of M13 vectors for selecting either DNA strand of double-digest restriction fragments

The strategy of shotgun cloning with M13 is based on obtaining random fragments used for the rapid accumulation of sequence data. A strategy, however, is sometimes needed for obtaining subcloned sequences preferentially out of a mixture of fragments. Shotgun sequencing experiments have shown that not all DNA fragments are obtained with the same frequency and that the redundant information increases during the last third of a sequencing project. In addition, experiments have shown that particular fragments are obtained more frequently in one orientation, allowing the use of only one of the two DNA strands as a template for M13 shotgun sequencing. Two new M13 vectors, M13mp8 and M13mp9, have been constructed that permit the cloning of the same restriction fragment in both possible orientations. Consequently, each of the two strands becomes a (+) strand in a pair of vectors. The fragments to be cloned are cleaved with two restriction enzymes to produce a fragment with two different ends. The insertion of such a fragment into the vector can occur only in one orientation. Since M13mp8 and M13mp9 have their array of cloning sites in an antiparallel order, either orientation for inserting a double-digest fragment can be selected by the choice of the vector.     

X-ray structures of the peridinin-chlorophyll-protein reconstituted with different chlorophylls

The peridinin-chlorophyll a-protein (PCP) from dinoflagellates is a soluble light harvesting antenna which gathers incoming photons mainly by the carotenoid peridinin. In PCPs reconstituted with different chlorophylls, the peridinin to chlorophyll energy transfer rates are well predicted by a Förster-like theory, but only if the pigment arrangements are identical in all PCPs. We have determined the X-ray structures of PCPs reconstituted with Chlorophyll-b (Chl-b), Chlorophyll-d (Chl-d) and Bacteriochlorophyll-a (BChl-a) to resolutions ?2 Å. In all three cases the pigment arrangements are essentially the same as in native PCP. Hydrogen bonding is not responsible for preferential incorporation of “non-native” chlorophylls over Chl-a.     

Estimation of whole‐body SAR from electromagnetic fields using personal exposure meters

In this article, personal electromagnetic field measurements are converted into whole‐body specific absorption rates for exposure of the general public. Whole‐body SAR values calculated from personal exposure meter data are compared for different human spheroid phantoms: the highest SAR values (at 950 MHz) are obtained for the 1‐year‐old child (99th percentile of 17.9 µW/kg for electric field strength of 0.36 V/m), followed by the 5‐year‐old child, 10‐year‐old child, average woman, and average man. For the 1‐year‐old child, whole‐body SAR values due to 9 different radiofrequency sources (FM, DAB, TETRA, TV, GSM900 DL, GSM1800 DL, DECT, UMTS DL, WiFi) are determined for 15 different scenarios. An SAR matrix for 15 different exposure scenarios and 9 sources is provided with the personal field exposure matrix. Highest 95th percentiles of the whole‐body SAR are equal to 7.9 µW/kg (0.36 V/m, GSM900 DL), 5.8 µW/kg (0.26 V/m, DAB/TV), and 7.1 µW/kg (0.41 V/m, DECT) for the 1‐year‐old child, with a maximal total whole‐body SAR of 11.5 µW/kg (0.48 V/m) due to all 9 sources. All values are below the basic restriction of 0.08 W/kg for the general public. 95th percentiles of whole‐body SAR per V/m are equal to 60.1, 87.9, and 42.7 µW/kg for GSM900, DAB/TV, and DECT sources, respectively. Functions of the SAR versus measured electric fields are provided for the different phantoms and frequencies, enabling epidemiological and dosimetric studies to make an analysis in combination with both electric field and actual whole‐body SAR. Bioelectromagnetics 31:286–295, 2010. © 2009 Wiley‐Liss, Inc.