24 research outputs found
Inhibition of Immune Complex-Induced Inflammation by A small Molecular Weight Selectin Antagonist
The anti-inflammatory effect of a small molecular weight antagonist
of P- and E-selectin-dependent cell adhesion was examined. The
glycolipid sulphatide was shown to block the adherence of
thrombin-activated rat platelets to HL-60 cells. This interaction is
known to be dependent on P-selectin. The rat dermal reverse passive
Arthus reaction was used to assess the effect of sulphatide on a
neutrophil dependent inflammatory response. Sulphatide
dosedependently blocked both the vascular permeability increase and
cell infiltration after intraperitoneal administration. These
results show that a small molecular weight compound which blocks P-
and E-selectin dependent adhesion in vitro can
effectively block the inflammation due to immune complex deposition.
A compound with this type of profile may have therapeutic potential
in the treatment of immune complex mediated diseases
Chandra Observation of V426 Oph: Weighing the Evidence for a Magnetic White Dwarf
We report the results of a 45 ks Chandra observation of the cataclysmic
variable V426 Ophiuchus. The high resolution spectrum from the high-energy
transmission grating spectrometer is most consistent with a cooling flow model,
placing V426 Oph among the group of CVs including U Gem and EX Hya. An
uninterrupted lightcurve was also constructed, in which we detect a significant
4.2 hr modulation together with its first harmonic at 2.1 hrs. Reanalysis of
archival Ginga, and ROSAT X-ray lightcurves also reveals modulations at periods
consistent with 4.2 and/or 2.1 hrs. Furthermore, optical photometry in V,
simultaneous with the Chandra observation, indicates a modulation
anti-correlated with the X-ray, and later more extensive R band photometry
finds a signal at ~2.1 hrs. The earlier reported X-ray periods at ~0.5 and 1
hrs appear to be only transient and quasi-periodic in nature. In contrast, the
4.2 hr period or its harmonic are stable and persistent in X-ray/optical data
from 1988 to 2003. This periodicity is clearly distinct from the 6.85 hr orbit,
and could be due to the spin of the white dwarf. If this is the case, V426 Oph
would be the first long period intermediate polar with a ratio P_spin/P_orb of
0.6. However, this interpretation requires unreasonable values of magnetic
field strength and mass accretion rate.Comment: 11 pages, 7 figures, 5 tables. Accepted for publication in the
Astrophysical Journal (to appear August 2004