423 research outputs found
Effect of heart failure on catecholamine granule morphology and storage in chromaffin cells
One of the key mechanisms involved in sympathoexcitation in chronic heart failure (HF) is the activation of the adrenal glands. Impact of the elevated catecholamines on the hemodynamic parameters has been previously demonstrated. However, studies linking the structural effects of such overactivation with secretory performance and cell metabolism in the adrenomedullary chromaffin cells in vivo have not been previously reported. In this study, HF was induced in male Sprague-Dawley rats by ligation of the left coronary artery. Five weeks after surgery, cardiac function was assessed by ventricular hemodynamics. HF rats showed increased adrenal weight and adrenal catecholamine levels (norepinephrine, epinephrine and dopamine) compared with sham-operated rats. Rats with HF demonstrated increased small synaptic and dense core vesicle in splanchnic–adrenal synapses indicating trans-synaptic activation of catecholamine biosynthetic enzymes, increased endoplasmic reticulum and Golgi lumen width to meet the demand of increased catecholamine synthesis and release, and more mitochondria with dilated cristae and glycogen to accommodate for the increased energy demand for the increased biogenesis and exocytosis of catecholamines from the adrenal medulla. These findings suggest that increased trans-synaptic activation of the chromaffin cells within the adrenal medulla may lead to increased catecholamines in the circulation which in turn contributes to the enhanced neurohumoral drive, providing a unique mechanistic insight for enhanced catecholamine levels in plasma commonly observed in chronic HF condition
Impact of Chromogranin A deficiency on catecholamine storage, catecholamine granule morphology and chromaffin cell energy metabolism in vivo
Chromogranin A (CgA) is a prohormone and granulogenic factor in neuroendocrine tissues with a regulated secretory pathway. The impact of CgA depletion on secretory granule formation has been previously demonstrated in cell culture. However, studies linking the structural effects of CgA deficiency with secretory performance and cell metabolism in the adrenomedullary chromaffin cells in vivo have not previously been reported. Adrenomedullary content of the secreted adrenal catecholamines norepinephrine (NE) and epinephrine (EPI) was decreased 30–40 % in Chga-KO mice. Quantification of NE and EPI-storing dense core (DC) vesicles (DCV) revealed decreased DCV numbers in chromaffin cells in Chga-KO mice. For both cell types, the DCV diameter in Chga-KO mice was less (100–200 nm) than in WT mice (200–350 nm). The volume density of the vesicle and vesicle number was also lower in Chga-KO mice. Chga-KO mice showed an ~47 % increase in DCV/DC ratio, implying vesicle swelling due to increased osmotically active free catecholamines. Upon challenge with 2 U/kg insulin, there was a diminution in adrenomedullary EPI, no change in NE and a very large increase in the EPI and NE precursor dopamine (DA), consistent with increased catecholamine biosynthesis during prolonged secretion. We found dilated mitochondrial cristae, endoplasmic reticulum and Golgi complex, as well as increased synaptic mitochondria, synaptic vesicles and glycogen granules in Chga-KO mice compared to WT mice, suggesting that decreased granulogenesis and catecholamine storage in CgA-deficient mouse adrenal medulla is compensated by increased VMAT-dependent catecholamine update into storage vesicles, at the expense of enhanced energy expenditure by the chromaffin cell
Investigation of complete and incomplete fusion in Li+Sn reaction around Coulomb barrier energies
The complete and incomplete fusion cross sections for Li+Sn
reaction were measured using online and offline characteristic -ray
detection techniques. The complete fusion (CF) cross sections at energies above
the Coulomb barrier were found to be suppressed by 26 \% compared to the
coupled channel calculations. This suppression observed in complete fusion
cross sections is found to be commensurate with the measured total incomplete
fusion (ICF) cross sections. There is a distinct feature observed in the ICF
cross sections, i.e., -capture is found to be dominant than
-capture at all the measured energies. A simultaneous explanation of
complete, incomplete and total fusion (TF) data was also obtained from the
calculations based on Continuum Discretized Coupled Channel method with short
range imaginary potentials. The cross section ratios of CF/TF and ICF/TF
obtained from the data as well as the calculations showed the dominance of ICF
at below barrier energies and CF at above barrier energies.Comment: 9 pages, 8 figure
Ross syndrome: a case report
Ross syndrome is a rare partial dysautonomic syndrome of unknown aetiology, characterized by segmental hypo/ anhidrosis associated with Holmes-Adie syndrome (tonic pupil and hypo/areflexia). The hypohydrosis or anhydrosis is patchy initially, later it becomes segmental or diffuse. This is due to affection of postganglionic cholinergic parasympathetic and sympathetic fibers involvement. There are a very few cases (approximately 50) have been reported in the literature since its original description. Author report a 22 years old male with classical features of Ross syndrome
Van der Knaap disease
Van der Knaap disease is a rare form of leukodystrophy, phenotypically characterized by megalencephaly, early-onset ataxia, pyramidal features, cognitive impairment, with an autosomal recessive inheritence. MRI Brain shows T1 and FLAIR hypointense subcortical cysts in mostly temporal lobes and in fronto-parietal subcortical areas. Authors report a 20 yr. girl with typical features
Observation and analysis of spatiotemporal characteristics of surface ozone and carbon monoxide at multiple sites in the Kathmandu Valley, Nepal
Residents of the Kathmandu Valley experience severe particulate
and gaseous air pollution throughout most of the year, even during much of
the rainy season. The knowledge base for understanding the air pollution in
the Kathmandu Valley was previously very limited but is improving rapidly
due to several field measurement studies conducted in the last few years.
Thus far, most analyses of observations in the Kathmandu Valley have been
limited to short periods of time at single locations. This study extends the
past studies by examining the spatial and temporal characteristics of two
important gaseous air pollutants (CO and O3) based on simultaneous
observations over a longer period at five locations within the valley and on
its rim, including a supersite (at Bode in the valley center, 1345 m above
sea level) and four satellite sites: Paknajol (1380 m a.s.l.) in the Kathmandu
city center; Bhimdhunga (1522 m a.s.l.), a mountain pass on the valley's
western rim; Nagarkot (1901 m a.s.l.), another mountain pass on the eastern
rim; and Naikhandi (1233 m a.s.l.), near the valley's only river outlet. CO and
O3 mixing ratios were monitored from January to July 2013, along with
other gases and aerosol particles by instruments deployed at the Bode
supersite during the international air pollution measurement campaign
SusKat-ABC (Sustainable Atmosphere for the Kathmandu Valley – endorsed by
the Atmospheric Brown Clouds program of UNEP). The monitoring of O3 at
Bode, Paknajol and Nagarkot as well as the CO monitoring at Bode were
extended until March 2014 to investigate their variability over a complete
annual cycle. Higher CO mixing ratios were found at Bode than at the outskirt
sites (Bhimdhunga, Naikhandi and Nagarkot), and all sites except Nagarkot
showed distinct diurnal cycles of CO mixing ratio, with morning peaks and
daytime lows. Seasonally, CO was higher during premonsoon (March–May) season
and winter (December–February) season than during monsoon season
(June–September) and postmonsoon (October–November) season. This is
primarily due to the emissions from brick industries, which are only
operational during this period (January–April), as well as increased domestic
heating during winter, and regional forest fires and agro-residue burning
during the premonsoon season. It was lower during the monsoon due to
rainfall, which reduces open burning activities within the valley and in the
surrounding regions and thus reduces sources of CO. The meteorology of the
valley also played a key role in determining the CO mixing ratios. The wind
is calm and easterly in the shallow mixing layer, with a mixing layer height
(MLH) of about 250 m, during the night and early morning. The MLH slowly
increases after sunrise and decreases in the afternoon. As a
result, the westerly wind becomes active and reduces the mixing ratio during
the daytime. Furthermore, there was evidence of an increase in the O3
mixing ratios in the Kathmandu Valley as a result of emissions in the
Indo-Gangetic Plain (IGP) region, particularly from biomass burning
including agro-residue burning. A top-down estimate of the CO emission flux
was made by using the CO mixing ratio and mixing layer height measured at
Bode. The estimated annual CO flux at Bode was 4.9 µg m−2 s−1,
which is 2–14 times higher than that in widely used emission
inventory databases (EDGAR HTAP, REAS and INTEX-B). This difference in CO
flux between Bode and other emission databases likely arises from large
uncertainties in both the top-down and bottom-up approaches to estimating the
emission flux. The O3 mixing ratio was found to be highest during the
premonsoon season at all sites, while the timing of the seasonal minimum
varied across the sites. The daily maximum 8 h average O3 exceeded
the WHO recommended guideline of 50 ppb on more days at the hilltop station
of Nagarkot (159 out of 357Â days) than at the urban valley bottom sites of Paknajol
(132 out of 354Â days) and Bode (102 out of 353Â days), presumably due to the influence of
free-tropospheric air at the high-altitude site (as also indicated by Putero
et al., 2015, for the Paknajol site in the Kathmandu Valley) as well as to
titration of O3 by fresh NOx emissions near the urban sites. More than
78 % of the exceedance days were during the premonsoon period at all
sites. The high O3 mixing ratio observed during the premonsoon periodÂ
is of a concern for human health and ecosystems, including agroecosystems in
the Kathmandu Valley and surrounding regions.</p
Role of Reactive Oxygen Species in Hyperadrenergic Hypertension: Biochemical, Physiological, and Pharmacological Evidence From Targeted Ablation of the Chromogranin A (Chga) Gene
Oxidative stress, an excessive production of reactive oxygen species (ROS) outstripping antioxidant defense mechanisms, occurs in cardiovascular pathologies including hypertension. Here, we used biochemical, physiological, and pharmacological approaches to explore the role of derangements of catecholamines, ROS, and NO• in the development of a hyper-adrenergic model of hereditary hypertension: targeted ablation (knockout, KO) of chromogranin A (Chga) in the mouse
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