207 research outputs found
Overall Lack of Regulated Secretion in a PC12 Variant Cell Clone
Abstract A stable clone of PC12 neuroendocrine cells, named 27, known from previous studies to exhibit a defect of regulated secretion (lack of regulated secretory proteins, of synaptophysin, of dense granules and of catecholamine uptake and release; Clementi, E., Racchetti, G., Zacchetti, D., Panzeri, M. C., and Meldolesi, J. (1992) Eur. J. Neurosci. 4, 944-953) was characterized in detail to clarify the nature of its phenotype and the mechanisms of its establishment. The neuroendocrine nature of the PC12-27 phenotype was documented by specific markers: synapsins, neurofilament subunit H, neuronal kinesin, and α-latrotoxin receptor. Moreover, various intracellular membrane systems of PC12-27, including the endoplasmic reticulum and the Golgi complex, appeared similar to control PC12 in both morphology and marker expression. In contrast, all the investigated markers located either in dense granules (dopamine-β-hydroxylase), in synaptic-like microvesicles (the acetylcholine transporter) or in both these regulated secretory organelles (VAMP2/synaptobrevin-2, synaptotagmin) were missing in PC12-27 cells, and the same was true also for the cytosolic and plasmalemma proteins involved in regulated exocytosis (Rab3, SNAP25, syntaxin). Pulse labeling and in vitro translation experiments revealed the defect to consist in a protein synthesis blockade that mRNA studies (reverse transcription-polymerase chain reaction, Northern blotting, and actinomycin D experiments) revealed to take place primarily at the transcriptional level. The secretion defect of PC12-27 cells was modified neither by various types of long term stimulation nor by nerve growth factor treatment. Moreover, when one of the missing regulated secretory proteins, chromogranin B, was expressed by cDNA transfection, it was secreted, however via the constitutive pathway. Our results demonstrate that PC12-27 cells are fully incompetent for both branches of regulated secretion, those of dense granules and synaptic-like microvesicles, possibly because of the impairment of a general expression control system that appears to operate independently of neuroendocrine cell differentiation
Sensitivity of projected long-term CO 2 emissions across the Shared Socioeconomic Pathways
Scenarios showing future greenhouse gas emissions are needed to estimate climate impacts and the mitigation efforts required for climate stabilization. Recently, the Shared Socioeconomic Pathways (SSPs) have been introduced to describe alternative social, economic and technical narratives, spanning a wide range of plausible futures in terms of challenges to mitigation and adaptation. Thus far the key drivers of the uncertainty in emissions projections have not been robustly disentangled. Here we assess the sensitivities of future CO 2 emissions to key drivers characterizing the SSPs. We use six state-of-the-art integrated assessment models with different structural characteristics, and study the impact of five families of parameters, related to population, income, energy efficiency, fossil fuel availability, and low-carbon energy technology development. A recently developed sensitivity analysis algorithm allows us to parsimoniously compute both the direct and interaction effects of each of these drivers on cumulative emissions. The study reveals that the SSP assumptions about energy intensity and economic growth are the most important determinants of future CO 2 emissions from energy combustion, both with and without a climate policy. Interaction terms between parameters are shown to be important determinants of the total sensitivities
Sympathetic Innervation of the Mammalian Pineal Gland: Its Involvement in Ontogeny and Physiology, and in Pineal Dysfunction
In mammals, the melatonin-producing pineal gland (PG) receives sympathetic innervation from the superior cervical ganglia (SCG). This chapter describes the role of this innervation on the PG’s ontogeny and rhythmic function, along with consequences to physiology when this regulation is disrupted. The PG and the SCG are components of the circadian timing system (CTS). Therefore, the overall CTS is described, including its oscillatory basis, its synchronization to the light: dark (L:D) cycles, and the dissemination of timing cues to all cells throughout the body. Pineal cellular composition and heterogeneity, cell-cell interactions, and the molecular mechanisms involved in the circadian rhythm of melatonin (MEL), are discussed. The SCG’s bilateral placement among surrounding anatomical landmarks, as well as their afferent and efferent connections, are described and illustrated. In addition, the SCG-related surgical models and the state-of-the art technology used to investigate the connection between SCG and PG are presented. Perspectives and gaps in our understanding are also discussed. We hope this chapter inspires readers to delve deeper into the field of the pineal gland and its main messenger, melatonin, as well as MEL’s impact in health and disease, including as a remedial therapy
Temporal properties of gamma-ray bursts as signatures of jets from the central engine
A comprehensive temporal analysis has been performed on the 319 brightest
GRBs with T90>2s from the BATSE current catalog. The rise times, fall times,
full-widths at half maximum (FWHM), pulse amplitudes and pulse areas were
measured and the frequency distributions are presented here. The distribution
of time intervals between pulses is not random but compatible with a lognormal
distribution when allowance was made for the 64 ms time resolution and a small
excess (5%) of long duration intervals that is often referred to as a
Pareto-Levy tail. A range of correlations are presented on pulse and burst
properties. The rise and fall times, FWHM and area of the pulses are highly
correlated with each other. The time intervals between pulses and pulse
amplitudes of neighbouring pulses are correlated with each other. It was also
found that the number of pulses, N, in GRBs is strongly correlated with the
fluence and the duration and that can explain the well known correlation
between duration and fluence. The GRBs were sorted into three catagories based
on N i.e. 3=25. The properties of pulses before and after
the stongest pulse were compared for the three catagories of bursts. This
analysis revealed that the GRBs with large numbers of pulses have narrower and
faster pulses and also larger fluences, longer durations and higher hardness
ratios than the GRBs with smaller numbers of pulses.Comment: 19 pages, 22 figures. Submitted to A&A July 200
Cloning and characterization of mouse UBPy, a deubiquitinating enzyme that interacts with the Ras guanine nucleotide exchange factor CDC25(Mm)/Ras-GRF1
We used yeast "two-hybrid" screening to isolate cDNA-encoding proteins interacting with the N-terminal domain of the Ras nucleotide exchange factor CDC25(Mm). Three independent overlapping clones were isolated from a mouse embryo cDNA library. The full-length cDNA was cloned by RACE-polymerase chain reaction. It encodes a large protein (1080 amino acids) highly homologous to the human deubiquitinating enzyme hUBPy and contains a well conserved domain typical of ubiquitin isopeptidases. Therefore we called this new protein mouse UBPy (mUBPy). Northern blot analysis revealed a 4-kilobase mRNA present in several mouse tissues and highly expressed in testis; a good level of expression was also found in brain, where CDC25(Mm) is exclusively expressed. Using a glutathione S-transferase fusion protein, we demonstrated an "in vitro" interaction between mUBPy and the N-terminal half (amino acids 1-625) of CDC25(Mm). In addition "in vivo" interaction was demonstrated after cotransfection in mammalian cells. We also showed that CDC25Mm, expressed in HEK293 cells, is ubiquitinated and that the coexpression of mUBPy decreases its ubiquitination. In addition the half-life of CDC25Mm protein was considerably increased in the presence of mUBPy. The specific function of the human homolog hUBPy is not defined, although its expression was correlated with cell proliferation. Our results suggest that mUBPy may play a role in controlling degradation of CDC25(Mm), thus regulating the level of this Ras-guanine nucleotide exchange factor
Challenging GRB models through the broadband dataset of GRB060908
Context: Multiwavelength observations of gamma-ray burst prompt and afterglow
emission are a key tool to disentangle the various possible emission processes
and scenarios proposed to interpret the complex gamma-ray burst phenomenology.
Aims: We collected a large dataset on GRB060908 in order to carry out a
comprehensive analysis of the prompt emission as well as the early and late
afterglow. Methods: Data from Swift-BAT, -XRT and -UVOT together with data from
a number of different ground-based optical/NIR and millimeter telescopes
allowed us to follow the afterglow evolution from about a minute from the
high-energy event down to the host galaxy limit. We discuss the physical
parameters required to model these emissions. Results: The prompt emission of
GRB060908 was characterized by two main periods of activity, spaced by a few
seconds of low intensity, with a tight correlation between activity and
spectral hardness. Observations of the afterglow began less than one minute
after the high-energy event, when it was already in a decaying phase, and it
was characterized by a rather flat optical/NIR spectrum which can be
interpreted as due to a hard energy-distribution of the emitting electrons. On
the other hand, the X-ray spectrum of the afterglow could be fit by a rather
soft electron distribution. Conclusions: GRB060908 is a good example of a
gamma-ray burst with a rich multi-wavelength set of observations. The
availability of this dataset, built thanks to the joint efforts of many
different teams, allowed us to carry out stringent tests for various
interpretative scenarios showing that a satisfactorily modeling of this event
is challenging. In the future, similar efforts will enable us to obtain
optical/NIR coverage comparable in quality and quantity to the X-ray data for
more events, therefore opening new avenues to progress gamma-ray burst
research.Comment: A&A, in press. 11 pages, 5 figure
Multi-wavelength observations of the energetic GRB 080810: detailed mapping of the broadband spectral evolution
GRB 080810 was one of the first bursts to trigger both Swift and the Fermi
Gamma-ray Space Telescope. It was subsequently monitored over the X-ray and
UV/optical bands by Swift, in the optical by ROTSE and a host of other
telescopes and was detected in the radio by the VLA. The redshift of z= 3.355
+/- 0.005 was determined by Keck/HIRES and confirmed by RTT150 and NOT. The
prompt gamma/X-ray emission, detected over 0.3-10^3 keV, systematically softens
over time, with E_peak moving from ~600 keV at the start to ~40 keV around 100
s after the trigger; alternatively, this spectral evolution could be identified
with the blackbody temperature of a quasithermal model shifting from ~60 keV to
~3 keV over the same time interval. The first optical detection was made at 38
s, but the smooth, featureless profile of the full optical coverage implies
that this originated from the afterglow component, not the pulsed/flaring
prompt emission.
Broadband optical and X-ray coverage of the afterglow at the start of the
final X-ray decay (~8 ks) reveals a spectral break between the optical and
X-ray bands in the range 10^15 - 2x10^16 Hz. The decay profiles of the X-ray
and optical bands show that this break initially migrates blueward to this
frequency and then subsequently drifts redward to below the optical band by
~3x10^5 s. GRB 080810 was very energetic, with an isotropic energy output for
the prompt component of 3x10^53 erg and 1.6x10^52 erg for the afterglow; there
is no evidence for a jet break in the afterglow up to six days following the
burst.Comment: 15 pages, 9 figures, 4 in colour. Accepted for publication in MNRA
A survey of clinical features of allergic rhinitis in adults
Background: Allergic rhinitis (AR) has high prevalence and substantial socio-economic burden.
Material/Methods: The study included 35 Italian Centers recruiting an overall number of 3383 adult patients with rhinitis (48% males, 52% females, mean age 29.1, range 18–45 years). For each patient, the attending physician had to fill in a standardized questionnaire, covering, in particular, some issues such as the ARIA classification of allergic rhinitis (AR), the results of skin prick test (SPT), the kind of treatment, the response to treatment, and the satisfaction with treatment.
Results: Out of the 3383 patients with rhinitis, 2788 (82.4%) had AR: 311 (11.5%) had a mild intermittent, 229 (8.8%) a mild persistent, 636 (23.5%) a moderate-severe intermittent, and 1518 (56.1%) a moderate-severe persistent form. The most frequently used drugs were oral antihistamines (77.1%) and topical corticosteroids (60.8%). The response to treatment was judged as excellent in 12.2%, good in 41.3%, fair in 31.2%, poor in 14.5%, and very bad in 0.8% of subjects. The rate of treatment dissatisfaction was significantly higher in patients with moderate-to-severe AR than in patients with mild AR (p<0.0001). Indication to allergen immunotherapy (AIT) was significantly more frequent (p<0.01) in patients with severe AR than with mild AR. .
Conclusions: These fndings confirm the appropriateness of ARIA guidelines in classifying the AR patients and the association of severe symptoms with unsuccessful drug treatment. The optimal targeting of patients to be treated with AIT needs to be reassessed
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