41 research outputs found
Observations of the neutral hydrogen surrounding the radio quiet neutron star RX J0822-4300 in Puppis A
We have observed the HI distribution in an area 40' x 40' around the neutron
star candidate RX J0822-4300, which is located in the supernova remnant Puppis
A. The observations of the 21 cm line were obtained with the Australia
Telescope Compact Array (ATCA) and were combined with single dish data from the
Southern Galactic Plane Survey. The spatial resolution is 90", and the velocity
resolution, 1 km/s . A sensitivity of ~ 0.7 K was achieved. The results
revealed a double lobed feature of reduced emission at +16 km/s, centered on
the central compact object (CCO), and aligned with an HI hole blueshifted by 13
km/s. The HI depressions have probably been created by the sweeping up of ~ 2
solar masses. The alignement between the lobes and the optical expansion centre
of Puppis A suggests that the CCO could be ejecting two opposite jets. The
velocity at which the two lobes are best defined allowed us to confirm that the
distance to Puppis A is 2.2 kpc, based on a systemic velocity of +16 km/s. The
hydrogen column density computed using this systemic velocity is consistent
with estimates from models for X-ray spectra, thus reinforcing our conclusion
that the kinematic distance is 2.2 k pc.Comment: 8 pages, 2 ps/eps figures, plus 1 gif figure and 4 jpg figures,
MNRAS, in press. Full postscript version with all 7 figures is available at
http://www.physics.usyd.edu.au/~simonj/puppis.ps.g
Two Individuals with Rare Blocked Antigen Phenomenon and Coinciding Warm Autoantibody Mimicking Alloanti-Jk3 Resolved with JK Analysis
Abstract
Introduction/Objective
Kidd antigens can bind complement (C3) as well as Kidd specific warm autoantibodies (WAAb). An 838G>A single nucleotide variant (SNV) defines JK*01 and JK*02 which codes the antithetical Jka and Jk b, respectively. Both alleles translate the high prevalence (>99%) Jk3 (JK3). The 130G>A is associated with weak Jka and weak Jkb expression. In vivo binding of non-agglutinating globulins can cause false-negative phenotypes by means of the blocked antigen phenomenon (BAP).
Methods/Case Report
Transfusions were requested for a 74-year-old Caucasian (CA) female with Evan’s Syndrome, and an 85-year-old African American (AA) female with metastatic uterine cancer. Both had a history of nonspecific WAAb. Direct antiglobulin testing (DAT) detected moderate in vivo sensitization of IgG and C3. They phenotyped Jk(a- b-) with untreated and EDTA glycine-acid (EGA) treated IgG DAT-negative cells. Their serum contained anti-Jk3 reactivity, while a panreactive WAAb in the eluate reacted with Jk3- donor and EGA treated DAT-negative autologous cells. Weak anti-Jka and anti-Jkb reactivity remained in the alloadsorbed serum of the antithetical adsorbing cells.
Genetic testing of the CA revealed JK*01W.01(130A)/02 alleles, while cDNA confirmed the alleles would be transcribed into mRNA. Sequencing of the AA detected 130G/A, and 838G/A as well as other silent mutations predicting either a Jk(a+wb+) or Jk(a+b+w) phenotype. The CA received one compatible JK:-3 transfusion, and both individuals benefited from multiple least incompatible transfusions of Jk a+ and/or Jk b+ donors with expected hemoglobin increases (1 g/dL per transfusion). The CA serologically phenotyped Jk(a-b+) 132 days later following prolonged immunosuppressive therapy while a normocytic normochromic anemia and the WAAb persisted. No follow up evaluations of the AA are available.
Results (if a Case Study enter NA)
NA
Conclusion
Unexpected BAP can confound immunohematology testing and lead WAAbs mimicking alloanti-Jk3 to be mischaracterized as allogeneic. By predicting phenotypes, genetic analysis can aid serological techniques in antibody characterization and help circumvent complications searching for rare JK:-3 donors.
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THE EFFECTS OF STRENGTH TRAINING ON BALANCE, GAIT AND CONFIDENCE MEASURES IN THE ELDERLY.
Enantioselective Syntheses of FR901464 and Spliceostatin A: Potent Inhibitors of Spliceosome
Promiscuity of a modular polyketide synthase towards natural and non-natural extender units
Improved Protein Kinase C Affinity through Final Step Diversification of a Simplified Salicylate-Derived Bryostatin Analog Scaffold
Computer-Guided Design, Synthesis, and Protein Kinase C Affinity of a New Salicylate-Based Class of Bryostatin Analogs
Aryl(sulfonyl)amino Group: A Convenient and Stable Yet Activated Modification of Amino Group for Its Intramolecular Displacement
Design, synthesis, and evaluation of potent bryostatin analogs that modulate PKC translocation selectivity
Modern methods for the identification of therapeutic leads include chemical or virtual screening of compound libraries. Nature’s library represents a vast and diverse source of leads, often exhibiting exquisite biological activities. However, the advancement of natural product leads into the clinic is often impeded by their scarcity, complexity, and nonoptimal properties or efficacy as well as the challenges associated with their synthesis or modification. Function-oriented synthesis represents a strategy to address these issues through the design of simpler and therefore synthetically more accessible analogs that incorporate the activity-determining features of the natural product leads. This study illustrates the application of this strategy to the design and synthesis of functional analogs of the bryostatin marine natural products. It is specifically directed at exploring the activity-determining role of bryostatin A-ring functionality on PKC affinity and selectivity. The resultant functional analogs, which were prepared by a flexible, modular synthetic strategy, exhibit excellent affinity to PKC and differential isoform selectivity. These and related studies provide the basic information needed for the design of simplified and thus synthetically more accessible functional analogs that target PKC isoforms, major targets of therapeutic interest
