Inflammation, oxidative stress, and obesity Fernández-Sánchez, Alba; Madrigal-Santillán, Eduardo; Bautista, Mirandeli ...
International Journal of Molecular Sciences,
05/2011, Letnik:
12, Številka:
5
Journal Article, Book Review
Recenzirano
Odprti dostop
Obesity is a chronic disease of multifactorial origin and can be defined as an increase in the accumulation of body fat. Adipose tissue is not only a triglyceride storage organ, but studies have ...shown the role of white adipose tissue as a producer of certain bioactive substances called adipokines. Among adipokines, we find some inflammatory functions, such as Interleukin-6 (IL-6); other adipokines entail the functions of regulating food intake, therefore exerting a direct effect on weight control. This is the case of leptin, which acts on the limbic system by stimulating dopamine uptake, creating a feeling of fullness. However, these adipokines induce the production of reactive oxygen species (ROS), generating a process known as oxidative stress (OS). Because adipose tissue is the organ that secretes adipokines and these in turn generate ROS, adipose tissue is considered an independent factor for the generation of systemic OS. There are several mechanisms by which obesity produces OS. The first of these is the mitochondrial and peroxisomal oxidation of fatty acids, which can produce ROS in oxidation reactions, while another mechanism is over-consumption of oxygen, which generates free radicals in the mitochondrial respiratory chain that is found coupled with oxidative phosphorylation in mitochondria. Lipid-rich diets are also capable of generating ROS because they can alter oxygen metabolism. Upon the increase of adipose tissue, the activity of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx), was found to be significantly diminished. Finally, high ROS production and the decrease in antioxidant capacity leads to various abnormalities, among which we find endothelial dysfunction, which is characterized by a reduction in the bioavailability of vasodilators, particularly nitric oxide (NO), and an increase in endothelium-derived contractile factors, favoring atherosclerotic disease.
One of the main issues in the medical field and clinical practice is the development of novel and effective treatments against infections caused by antibiotic-resistant bacteria. One avenue that has ...been approached to develop effective antimicrobials is the use of silver nanoparticles (Ag-NPs), since they have been found to exhibit an efficient and wide spectrum of antimicrobial properties. Among the main drawbacks of using Ag-NPs are their potential cytotoxicity against eukaryotic cells and the latent environmental toxicity of their synthesis methods. Therefore, diverse green synthesis methods, which involve the use of environmentally friendly plant extracts as reductive and capping agents, have become attractive to synthesize Ag-NPs that exhibit antimicrobial effects against resistant bacteria at concentrations below toxicity thresholds for eukaryotic cells.
In this study, we report a green one-pot synthesis method that uses
extract as a reducing and capping agent, to produce Ag-NPs with applications as therapeutic agents to treat infections in vivo.
The Ag-NPs were characterized using transmission electron microscopy (TEM), high-resolution TEM, selected area electron diffraction, energy-dispersive spectroscopy, ultraviolet-visible, and Fourier transform infrared.
We show that Ag-NPs are spherical with a narrow size distribution. The Ag-NPs show antimicrobial activities in vitro against Gram-negative (
,
, and a clinical multidrug-resistant strain of
) and Gram-positive (
) bacteria. Moreover, antimicrobial effects of the Ag-NPs, against a resistant
clinical strain, were tested in a murine skin infection model. The results demonstrate that the Ag-NPs reported in this work are capable of eradicating pathogenic resistant bacteria in an infection in vivo. In addition, skin, liver, and kidney damage profiles were monitored in the murine infection model, and the results demonstrate that Ag-NPs can be used safely as therapeutic agents in animal models.
Together, these results suggest the potential use of Ag-NPs, synthesized by green chemistry methods, as therapeutic agents against infections caused by resistant and nonresistant strains.
Francisella sp. is an emergent bacterial pathogen that causes acute to chronic disease in warm and cold water cultured and wild fish species. During the past 3 years, the bacterium has been detected ...in tilapia, Oreochromis niloticus, cultured in Costa Rica. Infected fish presented non-specific clinical signs, such as erratic swimming, anorexia, anaemia, exophthalmia and high mortality. Upon macroscopic and microscopic examination, several internal organs (mainly spleen and kidney) were enlarged and contained white nodules. Histological examination revealed the presence of multifocal granulomatous lesions, with the presence of numerous small, pleomorphic, cocco-bacilli. The bacteria were isolated from infected tilapia on selective media and grown on several media with and without antibiotics. Specific PCR primers to the Francisella genus were used to confirm the preliminary diagnoses. In comparison with several bacterial 16S rRNA sequences, our isolate was found to share 99% identity with other Fransicella spp. isolated from fish, and more than 97% identity to the human pathogen Francisella tularensis. Koch's postulates were fulfilled after experimental intraperitoneal and gill exposure challenges.
The CARMENES radial velocity (RV) survey is observing 324 M dwarfs to search for any orbiting planets. In this paper, we present the survey sample by publishing one CARMENES spectrum for each M ...dwarf. These spectra cover the wavelength range 520–1710 nm at a resolution of at least
R
>80 000, and we measure its RV, H
α
emission, and projected rotation velocity. We present an atlas of high-resolution M-dwarf spectra and compare the spectra to atmospheric models. To quantify the RV precision that can be achieved in low-mass stars over the CARMENES wavelength range, we analyze our empirical information on the RV precision from more than 6500 observations. We compare our high-resolution M-dwarf spectra to atmospheric models where we determine the spectroscopic RV information content,
Q
, and signal-to-noise ratio. We find that for all M-type dwarfs, the highest RV precision can be reached in the wavelength range 700–900 nm. Observations at longer wavelengths are equally precise only at the very latest spectral types (M8 and M9). We demonstrate that in this spectroscopic range, the large amount of absorption features compensates for the intrinsic faintness of an M7 star. To reach an RV precision of 1 m s
−1
in very low mass M dwarfs at longer wavelengths likely requires the use of a 10 m class telescope. For spectral types M6 and earlier, the combination of a red visual and a near-infrared spectrograph is ideal to search for low-mass planets and to distinguish between planets and stellar variability. At a 4 m class telescope, an instrument like CARMENES has the potential to push the RV precision well below the typical jitter level of 3–4 m s
−1
.
Context.
The main goal of the CARMENES survey is to find Earth-mass planets around nearby M-dwarf stars. Seven M dwarfs included in the CARMENES sample had been observed before with HIRES and HARPS ...and either were reported to have one short period planetary companion (GJ 15 A, GJ 176, GJ 436, GJ 536 and GJ 1148) or are multiple planetary systems (GJ 581 and GJ 876).
Aims.
We aim to report new precise optical radial velocity measurements for these planet hosts and test the overall capabilities of CARMENES.
Methods.
We combined our CARMENES precise Doppler measurements with those available from HIRES and HARPS and derived new orbital parameters for the systems. Bona-fide single planet systems were fitted with a Keplerian model. The multiple planet systems were analyzed using a self-consistent dynamical model and their best fit orbits were tested for long-term stability.
Results.
We confirm or provide supportive arguments for planets around all the investigated stars except for GJ 15 A, for which we find that the post-discovery HIRES data and our CARMENES data do not show a signal at 11.4 days. Although we cannot confirm the super-Earth planet GJ 15 Ab, we show evidence for a possible long-period (
P
c
= 7030
-630
+970
d) Saturn-mass (
m
c
sin
i
= 51.8
-5.8
+5.5
M
⊕
) planet around GJ 15 A. In addition, based on our CARMENES and HIRES data we discover a second planet around GJ 1148, for which we estimate a period
P
c
= 532.6
-2.5
+4.1
days, eccentricity
e
c
= 0.342
-0.062
+0.050
and minimum mass
m
c
sin
i
= 68.1
-2.2
+4.9
M
⊕
.
Conclusions.
The CARMENES optical radial velocities have similar precision and overall scatter when compared to the Doppler measurements conducted with HARPS and HIRES. We conclude that CARMENES is an instrument that is up to the challenge of discovering rocky planets around low-mass stars.
We report the first detection of a TeV 7-ray flux from the solar disk (6.3a), based on 6.1 years of data from the High Altitude Water Cherenkov (HAWC) observatory. The 0.5-2.6 TeV spectrum is well ...fit by a power law, dN/dE=A(E/1 TeV)-7, with A = (1.6 & PLUSMN; 0.3) x 10-12 TeV-1 cm-2 s-1 and 7 = 3.62 & PLUSMN; 0.14. The flux shows a strong indication of anticorrelation with solar activity. These results extend the bright, hard GeV emission from the disk observed with Fermi-LAT, seemingly due to hadronic Galactic cosmic rays showering on nuclei in the solar atmosphere. However, current theoretical models are unable to explain the details of how solar magnetic fields shape these interactions. HAWC's TeV detection thus deepens the mysteries of the solar-disk emission.
There have been no worldwide standardised surveys of prevalence and severity of asthma, rhinoconjunctivitis and eczema in school children for 15 years. The present study aims to provide this ...information.Following the exact International Study of Asthma and Allergies in Childhood (ISAAC) methodology (cross-sectional questionnaire-based survey) the Global Asthma Network (GAN) Phase I was carried out between 2015 and 2020 in many centres worldwide.The study included 157 784 adolescents (13-14 years of age) in 63 centres, in 25 countries; and 101 777 children (6-7 years of age) in 44 centres, in 16 countries. The current prevalence of symptoms, respectively, was: 11.0% and 9.1% for asthma; 13.3% and 7.7% for rhinoconjunctivitis; and 6.4% and 5.9% for eczema. For asthma ever, hay fever ever and eczema ever prevalence was 10.5% and 7.6%; 15.2% and 11.1%; and 10.6% and 13.4%. Centres in countries with low- or lower-middle- gross national income (LICs or L-MICs) had significantly lower prevalence of the three disease symptoms and diagnoses (except for hay fever). In children, the prevalence of asthma and rhinoconjunctivitis symptoms were higher in males, while the reverse occurred among adolescents. For eczema, while the prevalence among female adolescents was double that of males, there was no sex difference among children. Centre accounted for a non-negligible variability of all disease symptoms (10% to 20%).The burden of asthma, rhinoconjunctivitis and eczema vary widely among the limited number of countries studied. Although symptom prevalence is lower in LICs and L-MICs, it represents a considerable burden everywhere studied.
Asthma, hay fever and eczema are three common chronic conditions. There are no recent multi-country data on the burden of these three conditions in adults; the aims of this study are to fill this ...evidence gap.The Global Asthma Network (GAN) Phase I is a multi-country cross-sectional population-based study using the same core methodology as the International Study of Asthma and Allergies in Childhood (ISAAC) Phase III. It provides data on the burden of asthma, hay fever, and eczema not only in children and adolescents but also for the first time in their parents/guardians.Data were available from 193 912 adults (104 061 female; mean age 38 (sd 7.5)) in 43 centres in 17 countries. The overall prevalences (range) of symptoms of current wheeze, asthma ever, hay fever ever and eczema ever were 6.6% (0.9%-32.7%), 4.4%(0.9%-29.0%), 14.4%(2.8%-45.7%), and 9.9%(1.6%-29.5%), respectively. Centre prevalence varied considerably both between countries and within countries. There was a moderate correlation between hay fever ever and asthma ever, and between eczema ever and hay fever ever at the centre level. There were moderate to strong correlations between indicators of the burden of disease reported in adults and the two younger age groups.We found evidence for a substantial burden of asthma, hay fever ever and eczema ever in countries examined highlighting the major public health importance of these diseases. Prevention strategies and equitable access to effective and affordable treatments for these three conditions would help mitigate the avoidable morbidity they cause.
PDF
