603 research outputs found

    Margaret Chase Smith Library 2017 High School Essay Contest: Crusade against the Drugs, Not the Users

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    Each year the Margaret Chase Smith Library sponsors an essay contest for high school seniors. The essay prompt for 2017 was, How would you address the current lethal drug epidemic? The essays have been edited for length

    (The) Jewish diaspora of the sixth century before Christ ..

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    Typewritten sheets in cover. Thesis (M.A.)--Boston University This item was digitized by the Internet Archive. Bibliography: 2 p. at end

    Identification of Plasmodium falciparum var1CSA and var2CSA domains that bind IgM natural antibodies

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    Malaria in pregnancy is responsible for maternal anaemia, low-birth-weight babies and infant deaths. Plasmodium falciparum infected erythrocytes are thought to cause placental pathology by adhering to host receptors such as chondroitin sulphate A (CSA). CSA binding infected erythrocytes also bind IgM natural antibodies from normal human serum, a process that may facilitate placental adhesion or promote immune evasion. The parasite ligands that mediate placental adhesion are thought to be members of the variant erythrocyte surface antigen family P. falciparum erythrocyte membrane protein 1 (PfEMP1), encoded by the var genes. Two var gene sub-families, var1CSA and var2CSA, have been identified as parasite CSA binding ligands and are leading candidates for a vaccine to prevent pregnancy-associated malaria. We investigated whether these two var gene subfamilies implicated in CSA binding are also the molecules responsible for IgM natural antibody binding. By heterologous expression of domains in COS-7 cells, we found that both var1CSA and var2CSA PfEMP1 variants bound IgM, and in both cases the binding region was a DBL epsilon domain occurring proximal to the membrane. None of the domains from a control non-IgM-binding parasite (R29) bound IgM when expressed in COS-7 cells. These results show that PfEMP1 is a parasite ligand for non-immune IgM and are the first demonstration of a specific adhesive function for PfEMP1 epsilon type domains

    The Effects of Repeat Testing on Performance Scores Utilizing the Isostation B-200

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    The purpose of this experimental study was twofold: 1) to determine if there was a significant increase in performance, or learning effect, between the first and second test sessions on the Isostation B-200 for normal subjects, and 2) if so, was there a specific percentage of increase that can be attributed as a learning effect for each age, gender, or activity level. Twenty-two subjects (8 men, 14 women) with no prior history or treatment for low back pain were utilized in this study. All subjects were tested in two positions. First, in an upright standing position and second, in twenty degrees of trunk flexion. The subjects were asked to perform maximal isometric contractions in each direction of the sagittal, coronal, and transverse planes for both test positions. Subjects were retested between forty-eight and ninety-six hours post-initial testing. Several research articles have indicated the presence of a learning effect, but very few have shown a statistically significant increase in performance. The results of this research have shown significant increases for all trunk motions between first and second test sessions with the trunk in twenty degrees of flexion, with an average increase of 16.10%. A significant increase for trunk flexion and extension was also found in the upright position, with an average increase in performance of 9.03% for all motions. This study also indicates that there is a greater amount of learning displayed in females as compared to males. Based upon this study, clinicians should realize that increases in torque production ranging from zero to fifteen percent, between the first and second test trials on the Isostation B-200, may be due to a learning effect

    Bleaches: whitening effect and fabric strength

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    A well-conserved Plasmodium falciparum var gene shows an unusual stage-specific transcript pattern

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    The var multicopy gene family encodes Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) variant antigens, which, through their ability to adhere to a variety of host receptors, are thought to be important virulence factors. The predominant expression of a single cytoadherent PfEMP1 type on an infected red blood cell, and the switching between different PfEMP1 types to evade host protective antibody responses, are processes thought to be controlled at the transcriptional level. Contradictory data have been published on the timing of var gene transcription. Reverse transcription-polymerase chain reaction (RT-PCR) data suggested that transcription of the predominant var gene occurs in the later (pigmented trophozoite) stages, whereas Northern blot data indicated such transcripts only in early (ring) stages. We investigated this discrepancy by Northern blot, with probes covering a diverse var gene repertoire. We confirm that almost all var transcript types were detected only in ring stages. However, one type, the well-conserved varCSA transcript, was present constitutively in different laboratory parasites and does not appear to undergo antigenic variation. Although varCSA has been shown to encode a chondroitin sulphate A (CSA)-binding PfEMP1, we find that the presence of full-length varCSA transcripts does not correlate with the CSA-binding phenotype

    The crystal structure of superoxide dismutase from Plasmodium falciparum

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    Background: Superoxide dismutases (SODs) are important enzymes in defence against oxidative stress. In Plasmodium falciparum, they may be expected to have special significance since part of the parasite life cycle is spent in red blood cells where the formation of reactive oxygen species is likely to be promoted by the products of haemoglobin breakdown. Thus, inhibitors of P. falciparum SODs have potential as anti-malarial compounds. As a step towards their development we have determined the crystal structure of the parasite's cytosolic iron superoxide dismutase. Results: The cytosolic iron superoxide dismutase from P. falciparum (PfFeSOD) has been overexpressed in E. coli in a catalytically active form. Its crystal structure has been solved by molecular replacement and refined against data extending to 2.5 angstrom resolution. The structure reveals a two-domain organisation and an iron centre in which the metal is coordinated by three histidines, an aspartate and a solvent molecule. Consistent with ultracentrifugation analysis the enzyme is a dimer in which a hydrogen bonding lattice links the two active centres. Conclusion: The tertiary structure of PfFeSOD is very similar to those of a number of other iron-and manganese-dependent superoxide dismutases, moreover the active site residues are conserved suggesting a common mechanism of action. Comparison of the dimer interfaces of PfFeSOD with the human manganese-dependent superoxide dismutase reveals a number of differences, which may underpin the design of parasite-selective superoxide dismutase inhibitors

    Religion as education

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    This item was digitized by the Internet Archive. Thesis (M.A.)--Boston Universityhttps://archive.org/details/religionaseducat00kye

    The role of Plasmodium falciparum var genes in malaria in pregnancy

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    Sequestration of Plasmodium falciparum-infected erythrocytes in the placenta is responsible for many of the harmful effects of malaria during pregnancy. Sequestration occurs as a result of parasite adhesion molecules expressed on the surface of infected erythrocytes binding to host receptors in the placenta such as chondroitin sulphate A (CSA). Identification of the parasite ligand(s) responsible for placental adhesion could lead to the development of a vaccine to induce antibodies to prevent placental sequestration. Such a vaccine would reduce the maternal anaemia and infant deaths that are associated with malaria in pregnancy. Current research indicates that the parasite ligands mediating placental adhesion may be members of the P. falciparum variant surface antigen family PfEMP1, encoded by var genes. Two relatively well-conserved subfamilies of var genes have been implicated in placental adhesion, however, their role remains controversial. This review examines the evidence for and against the involvement of var genes in placental adhesion, and considers whether the most appropriate vaccine candidates have yet been identified

    Single nucleotide polymorphisms (SNPs) are highly conserved in rhesus (Macaca mulatta) and cynomolgus (Macaca fascicularis) macaques

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    Background: Macaca fascicularis (cynomolgus or longtail macaques) is the most commonly used nonhuman primate in biomedical research. Little is known about the genomic variation in cynomolgus macaques or how the sequence variants compare to those of the well-studied related species, Macaca mulatta (rhesus macaque). Previously we identified single nucleotide polymorphisms (SNPs) in portions of 94 rhesus macaque genes and reported that Indian and Chinese rhesus had largely different SNPs. Here we identify SNPs from some of the same genomic regions of cynomolgus macaques (from Indochina, Indonesia, Mauritius and the Philippines) and compare them to the SNPs found in rhesus. Results: We sequenced a portion of 10 genes in 20 cynomolgus macaques. We identified 69 SNPs in these regions, compared with 71 SNPs found in the same genomic regions of 20 Indian and Chinese rhesus macaques. Thirty six (52%) of the M. fascicularis SNPs were overlapping in both species. The majority (70%) of the SNPs found in both Chinese and Indian rhesus macaque populations were also present in M. fascicularis. Of the SNPs previously found in a single rhesus population, 38% (Indian) and 44% (Chinese) were also identified in cynomolgus macaques. In an alternative approach, we genotyped 100 cynomolgus DNAs using a rhesus macaque SNP array representing 53 genes and found that 51% (29/57) of the rhesus SNPs were present in M. fascicularis. Comparisons of SNP profiles from cynomolgus macaques imported from breeding centers in China (where M. fascicularis are not native) showed they were similar to those from Indochina. Conclusion: This study demonstrates a surprisingly high conservation of SNPs between M. fascicularis and M. mulatta, suggesting that the relationship of these two species is closer than that suggested by morphological and mitochondrial DNA analysis alone. These findings indicate that SNP discovery efforts in either species will generate useful resources for both macaque species. Identification of SNPs that are unique to regional populations of cynomolgus macaques indicates that location-specific SNPs could be used to distinguish monkeys of uncertain origin. As an example, cynomolgus macaques obtained from 2 different breeding centers in China were shown to have Indochinese ancestry.This work was supported by grants RR00163 and RR00166, from the National Center for Research Resources, National Institutes of Health
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