Protective efficacy against malaria of a combination sporozoite and erythrocytic stage vaccine

Most malariologists believe that optimal malaria vaccines will induce protective immune responses against different stages of the parasite's life cycle. A multiple antigen peptide (MAP) vaccine based on the Plasmodium yoelii circumsporozoite protein (PyCSP) protects mice against sporozoite challenge by inducing antibodies that prevent sporozoites from invading hepatocytes. A purified recombinant protein vaccine based on the P. yoelii merozoite surface protein-1 (PyMSP-1) protects mice against challenge with infected erythrocytes, presumably by inducing antibodies against the erythrocytic stage of the parasite. We now report studies designed to determine if the PyMSP-1 vaccine protects against challenge with sporozoites, the stage encountered in the field, and if immunization with a combination of the PyCSP and PyMSP-1 vaccines provides additive or synergistic protection against sporozoite challenge. In two experiments, using TiterMax or Ribi R-700 as adjuvant, 3 of 19 mice immunized with the PyMSP-1 vaccine were completely protected against sporozoite challenge. The remaining mice had significantly delayed onset and lower levels of peak parasitemia than did control mice (11.1 +/- 2.8% vs. 36.7 +/- 1.6% in experiment #2, P < 0.01). Immunization with the combination vaccine reduced by approximately 50% the level of antibodies induced to PyCSP and PyMSP-1, as compared to that induced by the individual components. However, in two experiments, there was evidence of additive protection. Six of 19 (31.6%) immunized with the PyCSP vaccine, 3 of 19 (15.8%) immunized with the PyMSP-1 vaccine, and 10 of 19 (52.6%) immunized with the combination were completely protected against sporozoit challenge. This modest increase in protection in the combination group may be a reflection of additive anti-PyCSP and anti-PyMSP-1 immunity, since mice in the combination group had diminished levels of antibodies to each components. These studies indicate that considerable work may be required to optimize the construction, delivery, and assessment of multi-stage malaria vaccines.     

Nipple aspirate fluid: a promising non-invasive method to identify cellular markers of breast cancer risk

To evaluate the feasibility of nipple aspiration and to identify intermediate markers of breast cancer risk, nipple aspirate fluid (NAF) was collected from 177 subjects using a modified breast pump. The first 33 subjects demonstrated that we could obtain NAF quickly, reliably and repeatedly. Specimens from the remaining 144 subjects were collected to evaluate promising cellular biomarkers. NAF was obtained in 167 out of 177 (94%) subjects overall and in 99% of the 144 most recent subjects. Sufficient NAF was obtained to evaluate cytology in 160 out of 167 (96%) cases and specimens were sufficiently cellular to analyse DNA markers in 53% of cases. Among the last 144 subjects, menopausal status did not influence the ability to obtain NAF. NAF cytology correlated with increased breast cancer risk (P = 0.002). Using computerized image analysis of NAF epithelial cells, DNA index (P = 0.0002), percentage of cells in G2M (P = 0.05) and percentage of cells with hypertetraploidy (P = 0.002) increased as cytology became more abnormal. Our data indicate that NAF can be obtained in essentially all eligible subjects; that breast epithelial cells are evaluable in > 95% of NAF samples for cytology and in over half of NAF samples for DNA index (ploidy) and cell cycle analysis; and that abnormal NAF cytology correlates with increased breast cancer risk. This suggests that biomarkers identified in nipple aspirate fluid may prove useful either as an adjunct to currently accepted breast cancer screening methods, or to evaluate response to a chemopreventive agent.     

Dynamic gamma: Application to LCD motion‐blur reduction

Abstract— A metric, “dynamic gamma,” to quantitatively evaluate the dynamic temporal response of an LCD device is proposed. Dynamic gamma, associated with 2‐D plots, is more suitable for quantitatively characterizing the dynamic characteristics of an LC panel. The dynamic gamma metric was applied to improve the temporal response of LCDs. From dynamic gamma data, overdrive tables can be derived. Dynamic gamma can also be used to evaluate the effectiveness of overdrive. With a second‐order dynamic gamma, the performance of different overdrive algorithms can be quantitatively assessed. The dynamic gamma metric was also applied to backlight flashing and developed a time adaptive overdrive algorithm. The new algorithm reduces the ghosting artifact due to the timing mismatch between LCD driving and backlight flashing. Experimental results from a simulated tracking camera confirms the advantages of the new algorithm designed using dynamic gamma.     

Investigation of cure in epoxy resins: Ultrasonic and thermally stimulated current measurements

Acoustic and thermally stimulated current measurements are reported as a function of cure for dicyanodiamide cured epoxy resins. It is found that the acoustic propagation is dominated by the generation of voids and does not directly reflect the extent of cure. In contrast, the thermally stimulated data correlate well with conductivity data, the amplitude of the space charge peak decreasing with increasing degree of cure and the dipole peak shifting to high temperatures as predicted from DSC data. Both methods exhibit potential as NDT methods for cure in resins.     

An additive for increasing the strength and modulus of amine-cured epoxy resins

The reaction product of 4-hydroxyacetanilide and 1,2-epoxy-3-phenoxypropane, when added at 19 wt% to a conventional epoxy-resin-curing agent mixture, increases the tensile strength of the cured system from 82 MPa to 123 MPa and increases the shear modulus (20°C, 1 Hz) from 970 MPa to 1560 MPa. As well as showing increased strength, the tensile-test specimens also fail in a ductile fashion, i.e., the slope of the stress–strain curve is negative at failure, with appreciable localized deformation occurring during fracture. For notched samples (compact tension specimens), the fracture properties are strongly strain-rate-dependent. At low strain rates the additive-containing sample has a fracture energy (??, critical strain energy release rate) about twice that of the additive-free control, but at higher strain rates ?? falls to about 65° of the control value. The critical stress for crack propagation is also strain-rate-dependent and is about 50% higher than the control at low strain rates and about 10% less than the control at higher strain rates. Dynamic mechanical analysis and dielectric loss measurements indicate that the additive causes a decrease in the T_g and a suppression of the β-relaxation. Chemically, the additive accelerates the cure process but does not significantly alter the final extent of reaction of the epoxy resin. After curing, the additive is almost totally extractable by solvent indicating that it is not chemicaly bound to the polymer. These observations are discussed in terms of the concept of antiplasticization.     

The hydrolysis of xylan by Cellulomonas preparations

Thin layer chromatography was demonstrated as an effective technique for observing the time course of hydrolysis of a substituted xylan (arabinoxylan) by crude preparations of Cellulomonas. The chromatograms revealed a sequential pattern of appearance of xylooligomers and arabinoxylooligomers, with early appearance of relatively large oligomers and subsequent accumulation of xylobiose and (to a lesser extent) xylose and arabinose. The pattern indicated that the dominant enzymic activity towards arabinoxylan is that of an endoxylanase.     

Some experimental tests of the functional significance of scent-marking by gerbils (Meriones unguiculatus).

Investigated the functional significance of male gerbil scent-marks in 4 experiments with 60 male and female Mongolian gerbils. In Exps I and II, males in a novel test environment marked more, groomed more, and urinated less in the presence of odors of a strange male than in their absence. Female odors elicited male marking more than did male odors. In Exps III and IV, females were selectively less aggressive toward familiar-smelling males in comparison with unfamiliar-smelling males. These results, in conjunction with field observations of related species, call into question the hypothesis that gerbil scent-marks function territorially and instead suggest that the primary targets are adult females. (34 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)