248 research outputs found
A prospective randomized trial of fk506 versus cyclosporine after human pulmonary transplantation
We have conducted a unique prospective randomized study to compare the effect of PK506 and cyclosporine (CsA) as the principal immunosuppressive agents after pulmonary transplantation. Between October 1991 and March 1993, 74 lung transplants (35 single lung transplants [SLT], 39 bilateral lung transplant [BLT]) were performed on 74 recipients who were randomly assigned to receive either FK or CsA. Thirty-eight recipients (19 SLT, 19 BLT) received FK and 36 recipients (16 SLT, 20 BLT) received CsA. Recipients receiving FK or CsA were similar in age, gender, preoperative New York Heart Association functional class, and underlying disease. Acute rejection (ACR) was assessed by clinical, radiographic, and histologic criteria. ACR was treated with methylprednisolone, 1 g i.v./day, for three days or rabbit antithymocyte globulin if steroid-resistant.During the first 30 days after transplant, one patient in the FK group died of cerebral edema, while two recipients treated with CsA died of bacterial pneumonia (1) and cardiac arrest (1) (P=NS). Although one-year survival was similar between the groups, the number of recipients free from ACR in the FK group was significantly higher as compared with the CsA group (P<0.05). Bacterial and viral pneumonias were the major causes of late graft failure in both groups. The mean number of episodes of ACR/ 100 patient days was significantly fewer in the FK group (1.2) as compared with the CsA group (2.0) (P<0.05). While only one recipient (1/36=3%) in the group treated with CsA remained free from ACR within 120 days of transplantation, 13% (5/38) of the group treated with FK remained free from ACR during this interval (P<0.05). The prevalence of bacterial infection in the CsA group was 1.5 episodes/100 patient days and 0.6 episodes/100 patient days in the FK group. The prevalence of cytomegaloviral and fungal infection was similar in both groups.Although the presence of bacterial, fungal, and viral infections was similar in the two groups, ACR occurred less frequently in the FK-treated group as compared with the CsA-treated group in the early postoperative period (<90 days). Early graft survival at 30 days was similar in the two groups, but intermediate graft survival at 6 months was better in the FK group as compared with the CsA group. © 1994 by Williams and Wilkins
Noise Measurement of Interacting Ferromagnetic Particles with High Resolution Hall Microprobes
We present our first experimental determination of the magnetic noise of a
superspinglass made of < 1 pico-liter frozen ferrofluid. The measurements were
performed with a local magnetic field sensor based on Hall microprobes operated
with the spinning current technique. The results obtained, though preliminary,
qualitatively agree with the theoretical predictions of Fluctuation-Dissipation
theorem (FDT) violation [1].Comment: 4pages, 2 figure
On Inflation with Non-minimal Coupling
A simple realization of inflation consists of adding the following operators
to the Einstein-Hilbert action: (partial phi)^2, lambda phi^4, and xi phi^2 R,
with xi a large non-minimal coupling. Recently there has been much discussion
as to whether such theories make sense quantum mechanically and if the inflaton
phi can also be the Standard Model Higgs. In this note we answer these
questions. Firstly, for a single scalar phi, we show that the quantum field
theory is well behaved in the pure gravity and kinetic sectors, since the
quantum generated corrections are small. However, the theory likely breaks down
at ~ m_pl / xi due to scattering provided by the self-interacting potential
lambda phi^4. Secondly, we show that the theory changes for multiple scalars
phi with non-minimal coupling xi phi dot phi R, since this introduces
qualitatively new interactions which manifestly generate large quantum
corrections even in the gravity and kinetic sectors, spoiling the theory for
energies > m_pl / xi. Since the Higgs doublet of the Standard Model includes
the Higgs boson and 3 Goldstone bosons, it falls into the latter category and
therefore its validity is manifestly spoiled. We show that these conclusions
hold in both the Jordan and Einstein frames and describe an intuitive analogy
in the form of the pion Lagrangian. We also examine the recent claim that
curvature-squared inflation models fail quantum mechanically. Our work appears
to go beyond the recent discussions.Comment: 14 pages, 2 figures. Version 2: Clarified findings and improved
wording. Elaborated important sections and removed an unnecessary section.
Added references. Version 3: Updated towards JHEP version. Version 4: Final
JHEP versio
An eclipsing binary distance to the Large Magellanic Cloud accurate to 2 per cent
In the era of precision cosmology it is essential to determine the Hubble
Constant with an accuracy of 3% or better. Currently, its uncertainty is
dominated by the uncertainty in the distance to the Large Magellanic Cloud
(LMC) which as the second nearest galaxy serves as the best anchor point of the
cosmic distance scale. Observations of eclipsing binaries offer a unique
opportunity to precisely and accurately measure stellar parameters and
distances. The eclipsing binary method was previously applied to the LMC but
the accuracy of the distance results was hampered by the need to model the
bright, early-type systems used in these studies. Here, we present distance
determinations to eight long-period, late- type eclipsing systems in the LMC
composed of cool giant stars. For such systems we can accurately measure both
the linear and angular sizes of their components and avoid the most important
problems related to the hot early-type systems. Our LMC distance derived from
these systems is demonstrably accurate to 2.2 % (49.97 +/- 0.19 (statistical)
+/- 1.11 (systematic) kpc) providing a firm base for a 3 % determination of the
Hubble Constant, with prospects for improvement to 2 % in the future.Comment: 34 pages, 5 figures, 13 tables, published in the Nature, a part of
our data comes from new unpublished OGLE-IV photometric dat
An overview of the current status of CMB observations
In this paper we briefly review the current status of the Cosmic Microwave
Background (CMB) observations, summarising the latest results obtained from CMB
experiments, both in intensity and polarization, and the constraints imposed on
the cosmological parameters. We also present a summary of current and future
CMB experiments, with a special focus on the quest for the CMB B-mode
polarization.Comment: Latest CMB results have been included. References added. To appear in
"Highlights of Spanish Astrophysics V", Proceedings of the VIII Scientific
Meeting of the Spanish Astronomical Society (SEA) held in Santander, 7-11
July, 200
Mass and Hot Baryons in Massive Galaxy Clusters from Subaru Weak Lensing and AMiBA SZE Observations
We present a multiwavelength analysis of a sample of four hot (T_X>8keV)
X-ray galaxy clusters (A1689, A2261, A2142, and A2390) using joint AMiBA
Sunyaev-Zel'dovich effect (SZE) and Subaru weak lensing observations, combined
with published X-ray temperatures, to examine the distribution of mass and the
intracluster medium (ICM) in massive cluster environments. Our observations
show that A2261 is very similar to A1689 in terms of lensing properties. Many
tangential arcs are visible around A2261, with an effective Einstein radius
\sim 40 arcsec (at z \sim 1.5), which when combined with our weak lensing
measurements implies a mass profile well fitted by an NFW model with a high
concentration c_{vir} \sim 10, similar to A1689 and to other massive clusters.
The cluster A2142 shows complex mass substructure, and displays a shallower
profile (c_{vir} \sim 5), consistent with detailed X-ray observations which
imply recent interaction. The AMiBA map of A2142 exhibits an SZE feature
associated with mass substructure lying ahead of the sharp north-west edge of
the X-ray core suggesting a pressure increase in the ICM. For A2390 we obtain
highly elliptical mass and ICM distributions at all radii, consistent with
other X-ray and strong lensing work. Our cluster gas fraction measurements,
free from the hydrostatic equilibrium assumption, are overall in good agreement
with published X-ray and SZE observations, with the sample-averaged gas
fraction of = 0.133 \pm 0.027, for our sample = (1.2 \pm
0.1) \times 10^{15} M_{sun} h^{-1}. When compared to the cosmic baryon fraction
f_b = \Omega_b/\Omega_m constrained by the WMAP 5-year data, this indicates
/f_b = 0.78 \pm 0.16, i.e., (22 \pm 16)% of the baryons are missing
from the hot phase of clusters.Comment: accepted for publication in ApJ; high resolution figures available at
http://www.asiaa.sinica.edu.tw/~keiichi/upfiles/AMiBA7/ms_highreso.pd
The Yuan-Tseh Lee Array for Microwave Background Anisotropy
The Yuan-Tseh Lee Array for Microwave Background Anisotropy (AMiBA) is the
first interferometer dedicated to studying the cosmic microwave background
(CMB) radiation at 3mm wavelength. The choice of 3mm was made to minimize the
contributions from foreground synchrotron radiation and Galactic dust emission.
The initial configuration of seven 0.6m telescopes mounted on a 6-m hexapod
platform was dedicated in October 2006 on Mauna Loa, Hawaii. Scientific
operations began with the detection of a number of clusters of galaxies via the
thermal Sunyaev-Zel'dovich effect. We compare our data with Subaru weak lensing
data in order to study the structure of dark matter. We also compare our data
with X-ray data in order to derive the Hubble constant.Comment: accepted for publication in ApJ (13 pages, 7 figures); a version with
high resolution figures available at
http://www.asiaa.sinica.edu.tw/~keiichi/upfiles/AMiBA7/pho_highreso.pd
S100A6 (Calcyclin) is a prostate basal cell marker absent in prostate cancer and its precursors
S100A6 (Calcyclin) is a calcium-binding protein that has been implicated in a variety of biological functions as well as tumorigenesis.
The aim of our study was to investigate the involvement of S100A6 during prostate cancer development and progression. Using
immunohistochemistry, the expression of S100A6 was examined in benign (n ¼ 66), premalignant (n ¼ 10), malignant (n ¼ 66) and
metastatic prostate (n ¼ 5) tissues arranged in a tissue-microarray or whole sections as well as in prostate cancer cell lines. The
S100A6 immunostaining pattern in tissues was compared with that of cytokeratin 5 (a basal cell marker) and 18 (a benign luminal cell
marker). In all cases of benign epithelium, intense S100A6 expression was seen in the basal cell layer with absent staining in luminal
cells. In all cases of prostatic adenocarcinoma (matched), metastatic lesions and 3/10 high-grade prostatic intraepithelial neoplasia
lesions, an absence of S100A6 was seen. Western blotting and RT–PCR analysis of cell lines showed S100A6 expression to be
absent in LNCaP, LNCaP-LN3 and LNCaP-Pro5 but present in Du145, PC3, PC-3M and PC-3M-LN4. LNCaP cells treated with 5-
Azacytidine, caused re-expression of S100A6 mRNA. Sequencing of bisulphite modified DNA showed CpG methylation within the
S100A6 promoter region and exon 1 of LNCaP, LNCaP-LN3 and LNCaP-Pro5 cell lines but not in Du145 cells. Our data suggest
that loss of S100A6 protein expression is common in prostate cancer development and may occur at an early stage. The mechanism
of loss of expression may involve hypermethylation of CpG sites. The finding of intense S100A6 expression in the basal cells of benign
glands but loss of expression in cancer could be useful as a novel diagnostic marker for prostate cancer
Disruption of Neuronal Autophagy by Infected Microglia Results in Neurodegeneration
There is compelling evidence to support the idea that autophagy has a protective function in neurons and its disruption results in neurodegenerative disorders. Neuronal damage is well-documented in the brains of HIV-infected individuals, and evidence of inflammation, oxidative stress, damage to synaptic and dendritic structures, and neuronal loss are present in the brains of those with HIV-associated dementia. We investigated the role of autophagy in microglia-induced neurotoxicity in primary rodent neurons, primate and human models. We demonstrate here that products of simian immunodeficiency virus (SIV)-infected microglia inhibit neuronal autophagy, resulting in decreased neuronal survival. Quantitative analysis of autophagy vacuole numbers in rat primary neurons revealed a striking loss from the processes. Assessment of multiple biochemical markers of autophagic activity confirmed the inhibition of autophagy in neurons. Importantly, autophagy could be induced in neurons through rapamycin treatment, and such treatment conferred significant protection to neurons. Two major mediators of HIV-induced neurotoxicity, tumor necrosis factor-α and glutamate, had similar effects on reducing autophagy in neurons. The mRNA level of p62 was increased in the brain in SIV encephalitis and as well as in brains from individuals with HIV dementia, and abnormal neuronal p62 dot structures immunoreactivity was present and had a similar pattern with abnormal ubiquitinylated proteins. Taken together, these results identify that induction of deficits in autophagy is a significant mechanism for neurodegenerative processes that arise from glial, as opposed to neuronal, sources, and that the maintenance of autophagy may have a pivotal role in neuroprotection in the setting of HIV infection
Inhibition of PIKfyve by YM-201636 Dysregulates Autophagy and Leads to Apoptosis-Independent Neuronal Cell Death
The lipid phosphatidylinositol 3,5-bisphosphate (PtdIns(3,5)P-2), synthesised by PIKfyve, regulates a number of intracellular membrane trafficking pathways. Genetic alteration of the PIKfyve complex, leading to even a mild reduction in PtdIns(3,5)P-2 results in marked neurodegeneration via an uncharacterised mechanism. In the present study we have shown that selectively inhibiting PIKfyve activity, using YM-201636, significantly reduces the survival of primary mouse hippocampal neurons in culture. YM-201636 treatment promoted vacuolation of endolysosomal membranes followed by apoptosis-independent cell death. Many vacuoles contained intravacuolar membranes and inclusions reminiscent of autolysosomes. Accordingly, YM-201636 treatment increased the level of the autophagosomal marker protein LC3-II, an effect that was potentiated by inhibition of lysosomal proteases, suggesting that alterations in autophagy could be a contributing factor to neuronal cell death
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