The Experts below are selected from a list of 288 Experts worldwide ranked by ideXlab platform
R. D. Jeffries - One of the best experts on this subject based on the ideXlab platform.
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The transition Region Structure of AR Lacertae.
Monthly Notices of the Royal Astronomical Society, 1991Co-Authors: R. D. JeffriesAbstract:Recent X-ray and ultraviolet observations of the eclipsing RS CVn binary, AR Lac, are reviewed. Constraints on the coronal geometry imply a mean pressure of >17 dyn cm −2 for plasma with a temperature >10 6 K, whereas the mean transition Region pressure for cooler plasma at a temperature of ∼10 5 K is found to be 0.5 dyn cm −2 . It is shown that this pressure discrepancy is inconsistent with a model of the outer atmosphere in which the transition Region is situated solely at the base of coronal loops, but rather, implies that a large volume of lower pressure cool plasma must exist somewhere in the atmosphere which may be responsible for the majority of the transition Region emission. The location and origin of this component is discussed
Tomoki Naoe - One of the best experts on this subject based on the ideXlab platform.
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Immunoglobulin variable Region Structure and B-cell malignancies.
International journal of hematology, 2001Co-Authors: Hitoshi Kiyoi, Tomoki NaoeAbstract:The enormous diversity of immunoglobulin (Ig) variable (V) gene sequences encoding the antibody repertoire are formed by the somatic recombination of relatively few genetic elements. In B-lineage malignancies, Ig gene rearrangements have been widely used for determining clonality and cell origin. The recent development of rapid cloning and sequencing techniques has resulted in a substantial accumulation of IgV Region sequences at various stages of B-cell development and has revealed stage-specific trends in the use of V, diversity, joining genes, the degree of noncoding nucleotide addition, and the rate of somatic mutations. Furthermore, sequences from B-lineage malignant cells nearly reflect the characteristics of the normal counterpart at each respective stage of development. Alternatively, from the IgV Region Structure of the malignant cells, it is possible to speculate at which stage of B-cell development the cells were transformed. As the complete nucleotide sequences of the human Ig heavy and Ig light V Region loci have now been determined, the study of Ig genetics has entered into the super-information era.
Frank J Waxman - One of the best experts on this subject based on the ideXlab platform.
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effect of immunoglobulin variable Region Structure on c3b and c4b deposition
Molecular Immunology, 1996Co-Authors: Kendra D White, Mark Barton Frank, Stephen I Foundling, Frank J WaxmanAbstract:Abstract Many of the biological activities of immunoglobulins, including interaction with the complement system, are attributed to the Structure of the heavy chain constant domains. However, previous studies indicated that immune complexes formed with independently derived isotype-matched pairs of monoclonal antibodies vary with respect to their capacity to activate complement and to serve as targets for C3b and C4b deposition. The goal of the present study was to provide a structural basis for explaining how variable domains influence C3b and C4b deposition on immunoglobulins. Heavy and light chain variable domains from a pair of IgG2a antibodies previously shown to differ in terms of complement activation and C3b and C4b deposition were cloned and sequenced. The two clones utilize distinct heavy and light variable Region genes and the translated amino acid sequence reveals several residues that could serve as potential targets for complement deposition which differs between the two antibodies. Molecular modeling suggests that many of the relevant differences between the two antibodies are located in solvent exposed portions of the heavy and light chain variable domains and that some of the relevant sites are located within the complementarity determining Regions. Differences in antibody affinity do not provide an explanation for the previously observed role of variable domains on interactions with the complement system. These data suggest that sequence variations within solvent-exposed variable domain residues may play a key role in C3b and C4b deposition on immunoglobulins.
Eugene O Major - One of the best experts on this subject based on the ideXlab platform.
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a classification scheme for human polyomavirus jcv variants based on the nucleotide sequence of the noncoding regulatory Region
Journal of NeuroVirology, 2001Co-Authors: Peter N Jensen, Eugene O MajorAbstract:The human polyomavirus JCV is responsible for the central nervous system (CNS) demyelination observed in cases of progressive multifocal leukoencephalopathy (PML). Lytic infection of oligodendrocytes, the cells that constitute the basis of myelin in the CNS, is established by JCV in conjunction with immunosuppressive conditions. Beyond this, however, many questions related to JCV pathogenesis remain unanswered. The JCV regulatory Region is a hypervariable noncoding sequence positioned between the early and late protein-coding Regions. The particular nucleotide sequence of a JCV regulatory Region affects levels of viral transcription and replication. Modifications to this promoter/enhancer Structure can alter the cellular host range and may be responsible for switching JCV between states of lytic and latent infection. The regulatory Region Structure has, therefore, been used to distinguish JCV variants. Nucleotide sequencing studies have uncovered numerous variations of regulatory Region Structure. Until now, however, no inclusive nomenclature existed that linked variants by regulatory Region Structure and/or activity. We have arranged all known variant JCV regulatory Regions into quadrants according to the integration of particular sequence sections and repetition of sequence section groups. This arrangement of regulatory Regions results in an updated nomenclature that is well-suited for describing the relationships between JCV variants. Four distinct structural forms (I-S, I-R, II-S, and II-R) are defined along with tissue tropisms. This design provides logical connections between the variant regulatory Regions and may be useful for elucidating crucial steps in JCV pathogenesis.
Hyung Jong Jin - One of the best experts on this subject based on the ideXlab platform.
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Isolation of human CYP4F2 genomic DNA and its 5′ end regulatory Region Structure
Archives of pharmacal research, 1998Co-Authors: Hyung Jong JinAbstract:Human cytochrome P450 4F2 shows high regioselectivity in ω-hydroxylation of stearic acid and leukotriene B4. As a first step of its regulation study, human cytochrome P450 4F2 genomic DNA was isolated from liver of a person who was administered Clofibrate for 10 years. From Southern hybridization, restriction enzyme digestion and sequencing experiments, isolated genomic DNA fragment was found to contain around 32 Kb DNA and more than 20 Kb of 5′ end regulatory Region. Sequences of the structural gene Region revealed exon 1 and exon 2. Further regulation studies would elucidate the feedback mechanisms of the oxidative degradation of fatty acids, inflammatory response and the clearance of leukotriene B4 in the liver. Furthermore, regulation study of this gene could explain the species difference in responses to peroxisome proliferator and help in the safety evaluation of peroxisome proliferating chemicals to human being.