13,000 research outputs found
Estrone and estradiol concentrations in human ovaries, testes, and adrenals during the first two years of life
To determine the origin of estrogens in infant blood, we measured estrone (E1) and estradiol (E2) in the gonads of 50 girls and 64 boys who died suddenly between birth and 2 yr of age as well as in the adrenals of 18 of these infant girls and 16 of the boys. In the adrenals, E1 [median, 2.8 ng/g (10.4 pmol/g); range, 1.1-4.8 ng/g (4.1- 17.8 pmol/g)] and E2 [median, 3.0 ng/g (10.9 pmol/g); range, 1.2-5.3 ng/g (4.4-19.5 pmol/g)] were found in similar concentrations and were independent of age and sex. In the gonads, E2 was the major estrogen, but the concentrations differed markedly between the sexes; E2 exceeded E1 almost 10-fold in the ovaries and 2-fold in the testes. On the average, the gonads of the infant girls had 5 times more E2 and 2 times more E1 than those of the boys. As in plasma, E2 concentrations were highest in the ovaries of 1- to 6-month-old girls [median, 10.5 ng/g (38.5 pmol/g); range, 1.1-55.1 ng/g (4.0-202.0 pmol/g)] and in testes of 1- to 3-month-old boys [median, 1.8 ng/g (6.6 pmol/g); range, 0.6- 6.4 ng/g (2.3-23.5 pmol/g)]. Ovarian E2 concentrations declined to less than 3.0 ng/g (11.0 pmol/g) by the end of the first year of life, and testicular E2 declined to less than 1.0 ng/g (3.7 pmol/g) after only 6 months of age. Gonadal estrogen concentrations paralleled changes in gonadal morphology. Ovarian weights varied in a pattern of rise and fall similar to that of ovarian E2 concentrations; the biggest ovaries contained multiple macroscopic cysts. Testicular E2 closely correlated with Leydig cell development and testicular testosterone concentrations. We infer, therefore, that the surge of plasma E2 in infant girls originates from ovarian follicles and that of boys from testicular Leydig cells, and that these both occur as a result of the postnatal surge in gonadotropin secretion. The basal plasma E1 and E2 pool, however, is derived from the adrenals and remains at a comparatively constant level in both sexe
simultaneous cycle sequencing assessment of tg m and tn tract length in cftr gene
The lengths of the dinucleotide (TG) m and mononucleotide T n repeats, both located at the intron 8/exon 9 splice acceptor site of the cystic fibrosis transmembrane conductance regulator (CFTR) gene whose mutations cause cystic fibrosis (CF), have been shown to influence the skipping of exon 9 in CFTR mRNA. This exon 9-skipped mRNA encodes a nonfunctional protein and is associated with various clinical manifestations in CF. As a result of growing interest in these repeats, several assessment methods have been developed, most of which are, however, cumbersome, multi-step, and time consuming. Here, we describe a rapid method for the simultaneous assessment of the lengths of both (TG) m and T n repeats, based on a nonradioactive cycle sequencing procedure that can be performed even without DNA extraction. This method determines the lengths of the (TG) m and T n tracts of both alleles, which in our samples ranged from TG 8 to TG 12 in the presence of T 5 , T 7 , and T 9 alleles, and also fully assesses the aplotypes. In addition, the repeats in the majority of these samples can be assessed by single-strand sequencing, with no need to sequence the other strand, thereby saving to sequence the other strand, thereby saving a considerable amount of time and effort
Self-Generated Magnetic Fields in Galactic Cooling Flows
Interstellar magnetic fields in elliptical galaxies are assumed to have their
origin in stellar fields that accompany normal mass loss from an evolving
population of old stars. The seed fields are amplified by interstellar
turbulence driven by stellar mass loss and supernova events. These disordered
fields are further amplified by time-dependent compression in the inward moving
galactic cooling flow and are expected to dominate near the galactic core.
Under favorable circumstances, fields similar in strength to those observed G can be generated solely from these natural
galactic processes. In general the interstellar field throughout elliptical
galaxies is determined by the outermost regions in the interstellar gas where
the turbulent dynamo process can occur. Because of the long hydrodynamic flow
times in galactic cooling flows, currently observed magnetic fields may result
from periods of intense turbulent field amplification that occurred in the
outer galaxy in the distant past. Particularly strong fields in ellipticals may
result from ancient galactic mergers or shear turbulence introduced at the
boundary between the interstellar gas and ambient cluster gas.Comment: 21 pages in AASTEX LaTeX with 2 figures; accepted by Astrophysical
Journa
The 1.4 GHz light curve of GRB 970508
We report on Westerbork 1.4 GHz radio observations of the radio counterpart
to -ray burst GRB~970508, between 0.80 and 138 days after this event.
The 1.4 GHz light curve shows a transition from optically thick to thin
emission between 39 and 54 days after the event. We derive the slope of the
spectrum of injected electrons () in two
independent ways which yield values very close to . This is in agreement
with a relativistic dynamically near-adiabatic blast wave model whose emission
is dominated by synchrotron radiation and in which a significant fraction of
the electrons cool fast.Comment: Paper I. Accepted for publication in the Astrophysical Journal
Letter
GRB 030329: 3 years of radio afterglow monitoring
Radio observations of gamma-ray burst (GRB) afterglows are essential for our
understanding of the physics of relativistic blast waves, as they enable us to
follow the evolution of GRB explosions much longer than the afterglows in any
other wave band. We have performed a three-year monitoring campaign of GRB
030329 with the Westerbork Synthesis Radio Telescopes (WSRT) and the Giant
Metrewave Radio Telescope (GMRT). Our observations, combined with observations
at other wavelengths, have allowed us to determine the GRB blast wave physical
parameters, such as the total burst energy and the ambient medium density, as
well as investigate the jet nature of the relativistic outflow. Further, by
modeling the late-time radio light curve of GRB 030329, we predict that the
Low-Frequency Array (LOFAR, 30-240 MHz) will be able to observe afterglows of
similar GRBs, and constrain the physics of the blast wave during its
non-relativistic phase.Comment: 5 pages, 2 figures, Phil. Trans. R. Soc. A, vol.365, p.1241,
proceedings of the Royal Society Scientific Discussion Meeting, London,
September 200
Oscillation Effects On Neutrinos From The Early Phase Of a Nearby Supernova
Neutrinos emitted during stellar core collapse leading to a supernova are
primarily of the electron neutrino type at source which may undergo oscillation
between flavor eigenstates during propagation to an earth-bound detector.
Although the number of neutrinos emitted during the pre-bounce collapse phase
is much smaller than that emitted in the post-bounce phase (in which all
flavors of neutrinos are emitted), a nearby supernova event may nevertheless
register a substantial number of detections from the pre-bounce phase at
SuperKamiokande (SK) and the Sudbury Neutrino Observatory (SNO). The
calorimetric measurement of the supernova neutrino fluence from this stage via
the charge current and neutral current detection channels in SNO and the
corresponding distortion of detected spectrum in SK over the no-oscillation
spectrum, can probe information about neutrino mass difference and mixing which
are illustrated here in terms of two- and three-flavor oscillation models
Time- and compartment-resolved proteome profiling of the extracellular niche in lung injury and repair
The extracellular matrix (ECM) is a key regulator of tissue morphogenesis and repair. However, its composition and architecture are not well characterized. Here, we monitor remodeling of the extracellular niche in tissue repair in the bleomycin-induced lung injury mouse model. Mass spectrometry quantified 8,366 proteins from total tissue and bronchoalveolar lavage fluid (BALF) over the course of 8 weeks, surveying tissue composition from the onset of inflammation and fibrosis to its full recovery. Combined analysis ofproteome, secretome, and transcriptome highlighted post-transcriptional events during tissue fibrogenesis and defined the composition of airway epithelial lining fluid. To comprehensively characterize the ECM, we developed a quantitative detergent solubility profiling (QDSP) method, which identified Emilin-2 and collagen-XXVIII as novel constituents of the provisional repair matrix. QDSP revealed which secreted proteins interact with the ECM, and showed drastically altered association of morphogens to the insoluble matrix upon injury. Thus, our proteomic systems biology study assigns proteins to tissue compartments and uncovers their dynamic regulation upon lung injury and repair, potentially contributing to the development of anti-fibrotic strategies
A dust disk surrounding the young A star HR4796A
We report the codiscovery of the spatially-resolved dust disk of the
Vega-like star HR 4796A. Images of the thermal dust emission at m show an elongated structure approximately 200 AU in diameter surrounding
the central A0V star. The position angle of the disk, , is consistent to the position angle of the M companion star,
, suggesting that the disk-binary system is being seen nearly
along its orbital plane. The surface brightness distribution of the disk is
consistent with the presence of an inner disk hole of approximately 50 AU
radius, as was originally suggested by Jura et al. on the basis of the infrared
spectrum. HR 4796 is a unique system among the Vega-like or Pictoris
stars in that the M star companion (a weak-emission T Tauri star) shows that
the system is relatively young, Myr. The inner disk hole may
provide evidence for coagulation of dust into larger bodies on a timescale
similar to that suggested for planet formation in the solar system.Comment: 12 pages, 3 PostScript figures, accepted for publication in
Astrophysical Journal Letter
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