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Using a recombinant protein antigen for antibody testing shows a sum of antibody responses to multiple different immune epitopes existing in the protein antigen. In contrast, the antibody testing to an immunogenic peptide epitope reflects a singular antibody response to the individual peptide epitope. Therefore, using a panel of peptide epitopes provides an advantage for profiling multiple singular antibody responses with potential to estimate recent malaria exposure in human infections. However, transitioning from malaria immune epitope peptide-based ELISA to an all peptide bead-based multiplex Luminex assay presents some challenges including variation in the ability of different peptides to bind beads. The aim of this study was to develop a peptide coupling method while demonstrating the utility of these peptide epitopes from multiple stage antigens of Plasmodium falciparum for measuring antibodies. Successful coupling of peptide epitopes to beads followed three steps: 1) development of a peptide tag appended to the C-terminus of each peptide epitope consisting of beta-alanine–lysine (x 4)--cysteine, 2) bead modification with a high concentration of adipic acid dihydrazide, and 3) use of the peptide epitope as a blocker in place of the traditional choice, bovine serum albumin (BSA). This new method was used to couple 12 peptide epitopes from multiple stage specific antigens of P. falciparum, 1 Anopheles mosquito salivary gland peptide, and 1 Epstein-Barr virus peptide as an assay control. The new method was applied to testing of IgG in pooled samples from 30 individuals with previously repeated malaria exposure in western Kenya and IgM and IgG in samples from 37 U.S. travelers with recent exposure to malaria. The new peptide-bead coupling method and subsequent multiplex Luminex assay showed reliable detection of IgG to all 14 peptides in Kenyan samples. Among 37 samples from U.S. travelers recently diagnosed with malaria, IgM and IgG to the peptide epitopes were detected with high sensitivity and variation. Overall, the U.S. travelers had a much lower positivity rates of IgM than IgG to different peptide epitopes, ranging from a high of 62.2% positive for one epitope to a low of only 5.4% positive for another epitope. In contrast, the travelers had IgG positive rates from 97.3% to 91.9% to various peptide epitopes. Based on the different distribution in IgM and IgG positivity to overall number of peptide epitopes and to the number of pre-erythrocytic, erythrocytic, gametocytic, and salivary stage epitopes at the individual level, four distinct patterns of IgM and IgG responses among the 37 samples from US travelers were observed. Independent peptide-bead coupling and antibody level readout between two different instruments also showed comparable results. Overall, this new coupling method resolves the peptide-bead coupling challenge, is reproducible, and can be applied to any other immunogenic peptide epitopes. The resulting all peptide bead-based multiplex Luminex assay can be expanded to include other peptide epitopes of P. falciparum, different malaria species, or other diseases for surveillance, either in US travelers or endemic areas.

Injection molding is an important industrial technique for producing large quantities of identical polymer and polymer composite parts. Although alumina of any kind is abrasive and damaging to the steel molds, a technique was developed that reduces both the mold abrasion and the effective atomic number of the composite polymer dosimeter [Miller, S. 1996a. U.S. Patent No. 5,567,948, issued 22 October 1996; Miller, S. 1996b. U.S. Patent No. 5,569,927, issued 29 October 1996; Miller, S. 1998. U.S. Patent No. 5,731,590, issued 24 March 1998.]. Radiation oncology dose measurement applications would benefit from a large uniform batch of high-precision dosimeters ( 2 % , 1 sigma measurement precision). This new, high-precision dosimeter would eliminate the need to calibrate each dosimeter individually, as is currently the case with the thermoluminescence dosimeter measurements performed by the radiation oncology community.

Coronary heart disease is the leading cause of death in the United States. Heart disease can take many forms, the most severe of which is myocardial infarction (MI), also known as heart attack. Ventricular restoration (VR) is an approach to treating MI that involves excising the infarction and replacing it with a cardiac patch to restore the heart to a more natural shape. Commercially available patches such as Dacron and ePTFE are passive and do not contribute to the work of the heart once implanted. We propose the design of a new myocardial patch for VR that will induce regeneration and improve long-term heart function. To this end, we have undertaken an iterative design process to develop the required characteristics of such a patch. A composite scaffold design was developed that is composed of an endocardial patch to provide mechanical stability and an injectable filler material that will induce myocardial regeneration. The outcome of this project is the final design of a patch for ventricular restoration that is intended to regenerate myocardium and improve heart function.

In Fiscal Year 1989, the instrument sets were used to intercompare calibration fields associated with {sup 137}Cs, {sup 60}Co, {sup 90}Sr, {sup 241}AmBe and {sup 252}Cf. The results of the delivered-to-measured exposure rate and absorbed dose rate ratios were 1.00 {plus minus} 0.01 for photon measurements, 1.01 {plus minus} 0.01 for TLD measurements, 1.00 {plus minus} 0.02 for neutron measurements and a ratio of 1.03 for beta measurements. From the excellent agreement shown here it is evident that the radiological calibration intercomparison program is achieving its objective. 12 refs., 3 figs., 8 tabs.

Calibration measurements for personnel dosimetry purposes must be both accurate and consistent with national standards. In order to satisfy these requirements, the following methods are usually employed. In one case, a radiation source is sent to the National Institute of Standards and Technology (NIST), formerly the National Bureau of Standards, for calibration and is returned to the laboratory to be used as a local standard. Another method involves the calibration of an instrument, such as an ionization chamber, by NIST. After calibration, this instrument is then used to measure the exposure rate delivered by radiation sources at the laboratory. Such calibrations by NIST are essential, but they do not provide a complete check on the quality of the calibrations that are carried out by the individual laboratory. Additional measurements are necessary to assure the quality of such measurements. When laboratory staff are asked to carry our measurements with calibrated instruments and report results for evaluation, they are participating in a measurement quality assurance (MQA) program. Such a program tests not only the quality of the equipment but also the ability of the staff to correctly use and interpret the results obtained with the equipment. The NIST operates an MQA programmore » with a selected number of calibration laboratories. Pacific Northwest Laboratory (PNL) participates in this MQA program even though NIST test only x-ray and gamma-ray measurements. The US Department of Energy (DOE) intercomparison program was designed specifically to include x-ray, gamma-ray, beta, and neutron calibrations for personnel dosimetry purposes. This program serves a need that is not being met by NIST, and it provides documentation of the accuracy and uniformity of the radiological calibrations carried out in DOE facilities. 7 refs., 3 figs., 6 tabs.« less