437 research outputs found
Oxidative stress in diabetic patients with retinopathy
Background: Diabetes mellitus (DM) is known to induce oxidative stress along with deranging various metabolisms; one of the late complications of diabetes mellitus is diabetic retinopathy, which is a leading cause of acquired blindness. Poor glycemic control and oxidative stress have been attributed to the development of complications like diabetic retinopathy. The aim of this study was to analyze and correlate oxidative stress marker, Malondialdehyde (MDA), and antioxidants (erythrocyte glutathione, vitamin C) along with glycosylated hemoglobin (HbA1c) and fasting blood sugar (FBS) in diabetic patients with and without retinopathy.Materials and Methods: The study population comprised of 50 type 2 diabetics with retinopathy as Group 1 (G1) and 50 type 2 diabetics without retinopathy as Group 2 (G2) in the age group 40-70 years as patients, and 50 ageand gender-matched healthy individuals as controls, Group 3 (G3). FBS, HbA1c MDA, glutathione in erythrocytes, and vitamin C were assayed. Results were analyzed using SPSS 11.0, MannâWhitney U-test, and Pearson correlation coefficient.Results: Mean FBS (mg/dl) were 194.04 ± 48.52 (G1), 181.24 ± 50.05 (G2), and 92.20 ± 9.19 (G3) (P < 0.001). Mean values of MDA were 6.65 ± 0.30 (G1), 4.63 ± 0.56 (G2), and 3.90 ± 0.34 (G3) (P < 0.001). The mean reduced glutathione (GSH) levels were (mg/g of Hb) 6.10 ± 1.41 (G1), 6.44 ± 1.53 (G2), and 13.09 ± 2.49 (G3) (P < 0.001). The mean vitamin C levels (mg/dl) were 0.70 ± 0.24 (G1), 0.87 ± 0.29 (G2), and 1.25 ± 0.27 (G3) (P < 0.001).Conclusion: Estimation of HbA1c, MDA, GSH in erythrocytes, and vitamin C levels can contribute to determine the extent of oxidative stress in diabetes and help in effective control and prevention of the onset and progression of diabetic retinopathy.Keywords: Diabetic retinopathy, glycosylated hemoglobin, malondialdehyde, reduced glutathione, vitamin
Astrometric and photometric monitoring of GQ Lup and its sub-stellar companion
Neuhaeuser et al. (2005) presented direct imaging evidence for a sub-stellar
companion to the young T Tauri star GQ Lup. Common proper motion was highly
significant, but no orbital motion was detected. Faint luminosity, low gravity,
and a late-M/early-L spectral type indicated that the companion is either a
planet or a brown dwarf. We have monitored GQ Lup and its companion in order to
detect orbital and parallactic motion and variability in its brightness. We
also search for closer and fainter companions. We have taken six more images
with the VLT Adaptive Optics instrument NACO from May 2005 to Feb 2007, always
with the same calibration binary from Hipparcos for both astrometric and
photometric calibration. By adding up all the images taken so far, we search
for additional companions. The position of GQ Lup A and its companion compared
to a nearby non-moving background object varies as expected for parallactic
motion by about one pixel (2 \pi with parallax \pi). We could not find evidence
for variability of the GQ Lup companion in the K-band (standard deviation being
\pm 0.08 mag), which may be due to large error bars. No additional companions
are found with deep imaging. There is now exceedingly high significance for
common proper motion of GQ Lup A and its companion. In addition, we see for the
first time an indication for orbital motion (about 2 to 3 mas/yr decrease in
separation, but no significant change in the position angle), consistent with a
near edge-on or highly eccentric orbit. We measured the parallax for GQ Lup A
to be \pi = 6.4 \pm 1.9 mas (i.e. 156 \pm 50 pc) and for the GQ Lup companion
to be 7.2 \pm 2.1 mas (i.e. 139 \pm 45 pc), both consistent with being in the
Lupus I cloud and bound to each other.Comment: A&A in pres
A Radial Velocity Study of Composite-Spectra Hot Subdwarf Stars with the Hobby-Eberly Telescope
Many hot subdwarf stars show composite spectral energy distributions
indicative of cool main sequence companions. Binary population synthesis (BPS)
models demonstrate such systems can be formed via Roche lobe overflow or common
envelope evolution but disagree on whether the resulting orbital periods will
be long (years) or short (days). Few studies have been carried out to assess
the orbital parameters of these spectroscopic composite binaries; current
observations suggest the periods are long. To help address this problem, we
selected fifteen moderately-bright (V~13) hot subdwarfs with F-K dwarf
companions and monitored their radial velocities (RVs) from January 2005 to
July 2008 using the bench-mounted Medium Resolution Spectrograph on the
Hobby-Eberly Telescope (HET). Here we describe the details of our observing,
reduction, and analysis techniques and present preliminary results for all
targets. By combining the HET data with recent observations from the Mercator
telescope, we are able to calculate precise orbital solutions for three systems
using more than 6 years of observations. We also present an up-to-date period
histogram for all known hot subdwarf binaries, which suggests those with F-K
main sequence companions tend to have orbital periods on the order of several
years. Such long periods challenge the predictions of conventional BPS models,
although a larger sample is needed for a thorough assessment of the models'
predictive success. Lastly, one of our targets has an eccentric orbit, implying
some composite-spectrum systems might have formerly been hierarchical triple
systems, in which the inner binary merged to create the hot subdwarf.Comment: Published in The Astrophysical Journal, Volume 758, Issue 1, article
id. 58 (2012). References updated and Equation (5) corrected. 12 pages, 5
figures, 5 table
Unsteady Extinction of Opposed Jet Ethylene/Methane HIFiRE Surrogate Fuel Mixtures vs Air
A unique idealized study of the subject fuel vs. air systems was conducted using an Oscillatory-input Opposed Jet Burner (OOJB) system and a newly refined analysis. Extensive dynamic-extinction measurements were obtained on unanchored (free-floating) laminar Counter Flow Diffusion Flames (CFDFs) at 1-atm, stabilized by steady input velocities (e.g., U(sub air)) and perturbed by superimposed in-phase sinusoidal velocity inputs at fuel and air nozzle exits. Ethylene (C2H4) and methane (CH4), and intermediate 64/36 and 15/85 molar percent mixtures were studied. The latter gaseous surrogates were chosen earlier to mimic ignition and respective steady Flame Strengths (FS = U(sub air)) of vaporized and cracked, and un-cracked, JP-7 "like" kerosene for a Hypersonic International Flight Research Experimentation (HIFiRE) scramjet. For steady idealized flameholding, the 100% C2H4 flame is respectively approx. 1.3 and approx.2.7 times stronger than a 64/36 mix and CH4; but is still 12.0 times weaker than a 100% H2-air flame. Limited Hot-Wire (HW) measurements of velocity oscillations at convergent-nozzle exits, and more extensive Probe Microphone (PM) measurements of acoustic pressures, were used to normalize Dynamic FSs, which decayed linearly with pk/pk U(sub air) (velocity magnitude, HW), and also pk/pk P (pressure magnitude, PM). Thus Dynamic Flame Weakening (DFW) is defined as % decrease in FS per Pascal of pk/pk P oscillation, namely, DFW = -100 d(U(sub air)/U(sub air),0Hz)/d(pkpk P). Key findings are: (1) Ethylene flames are uniquely strong and resilient to extinction by oscillating inflows below 150 Hz; (2) Methane flames are uniquely weak; (3) Ethylene / methane surrogate flames are disproportionately strong with respect to ethylene content; and (4) Flame weakening is consistent with limited published results on forced unsteady CFDFs. Thus from 0 to approx. 10 Hz and slightly higher, lagging diffusive responses of key species led to progressive phase lags (relative to inputs) in the oscillating flames, and caused maximum weakening. At 20 to 150 Hz, diffusion-rate-limited effects diminished, causing flames to "regain strengnth," and eventually become completely insensitive beyond 300 Hz. Detailed mechanistic understanding is needed. Overall, ethylene flames are remarkably resilient to dynamic extinction by oscillating inflows. They are the strongest, with the notable exception of H2. For HIFiRE tests, the 64%/36% surrogate disproportionally retains the high dynamic FS of ethylene, so the potential for loss of scramjet flameholding (flameout) due to low frequency oscillations is significantly mitigated
Increased Hepatitis E Virus Seroprevalence Correlates with Lower CD4+Cell Counts in HIV-Infected Persons in Argentina
Hepatitis E virus (HEV) is a single-stranded RNA virus that can cause hepatitis in an epidemic fashion. HEV usually causes asymptomatic or limited acute infections in immunocompetent individuals, whereas in immunosuppressed individuals such as transplant recipients, HEV can cause chronic infections. The risks and outcomes of HEV co-infection in patients infected with human immunodeficiency virus (HIV) are poorly characterized. We used a third generation immunoassay to measure serum IgG antibodies specific for HEV in 204 HIV-infected individuals from Argentina and a control group of 433 HIV-negative individuals. We found 15 of 204 (7.3%, 95% CI 3.74-10.96%) individuals in the HIV-positive group to have positive HEV IgG levels suggestive of previous infection, compared to 19 of 433 (4.4%, 95% CI 2.5-6.3%) individuals in the HIV-negative control group (p = 0.12). Among HIV-positive individuals, those with HEV seropositivity had lower CD4 counts compared to those that were HEV seronegative (average CD4 count of 234 vs 422 mm(3), p = 0.01), indicating that patients with lower CD4 counts were more likely to be HEV IgG positive. Moreover, HEV seropositivity in patients with CD4 counts <200 mm(3) was 16%, compared to 4.5% in those with CD4 counts >200 mm(3) (p = 0.012). We found a positive PCR result for HEV in one individual. Our study found that increased seroprevalence of HEV IgG correlated with lower CD4 counts in HIV-infected patients in Argentina
Spectral modeling of gaseous metal disks around DAZ white dwarfs
We report on our attempt for the first non-LTE modeling of gaseous metal
disks around single DAZ white dwarfs recently discovered by Gaensicke et al.
and thought to originate from a disrupted asteroid. We assume a Keplerian
rotating viscous disk ring composed of calcium and hydrogen and compute the
detailed vertical structure and emergent spectrum. We find that the observed
infrared CaII emission triplet can be modeled with a hydrogen-deficient gas
ring located at R=1.2 R_sun, inside of the tidal disruption radius, with Teff
about 6000 K and a low surface mass density of about 0.3 g/cm**2. A disk having
this density and reaching from the central white dwarf out to R=1.2 R_sun would
have a total mass of 7 10**21 g, corresponding to an asteroid with about 160 km
diameter.Comment: Proceedings, 16th European White Dwarf Workshop, Barcelona, 200
Pulsational Mapping of Calcium Across the Surface of a White Dwarf
We constrain the distribution of calcium across the surface of the white
dwarf star G29-38 by combining time series spectroscopy from Gemini-North with
global time series photometry from the Whole Earth Telescope. G29-38 is
actively accreting metals from a known debris disk. Since the metals sink
significantly faster than they mix across the surface, any inhomogeneity in the
accretion process will appear as an inhomogeneity of the metals on the surface
of the star. We measure the flux amplitudes and the calcium equivalent width
amplitudes for two large pulsations excited on G29-38 in 2008. The ratio of
these amplitudes best fits a model for polar accretion of calcium and rules out
equatorial accretion.Comment: Accepted to the Astrophysical Journal. 16 pages, 10 figures
Increased hepatitis E virus seroprevalence correlates with lower CD4+ cell counts in HIV-infected persons in Argentina
Hepatitis E virus (HEV) is a single-stranded RNA virus that can cause hepatitis in an epidemic fashion. HEV usually causes asymptomatic or limited acute infections in immunocompetent individuals, whereas in immunosuppressed individuals such as transplant recipients, HEV can cause chronic infections. The risks and outcomes of HEV co-infection in patients infected with human immunodeficiency virus (HIV) are poorly characterized. We used a third generation immunoassay to measure serum IgG antibodies specific for HEV in 204 HIV-infected individuals from Argentina and a control group of 433 HIV-negative individuals. We found 15 of 204 (7.3%, 95%CI 3.74-10.96%) individuals in the HIV-positive group to have positive HEV IgG levels suggestive of previous infection, compared to 19 of 433 (4.4%, 95% CI 2.5-6.3%) individuals in the HIV-negative control group (p = 0.12). Among HIV-positive individuals, those with HEV seropositivity had lower CD4 counts compared to those that were HEV seronegative (average CD4 count of 234 vs 422 mm3, p = 0.01), indicating that patients with lower CD4 counts were more likely to be HEV IgG positive. Moreover, HEV seropositivity in patients with CD4 counts 200 mm3 (p = 0.012). We found a positive PCR result for HEV in one individual. Our study found that increased seroprevalence of HEV IgG correlated with lower CD4 counts in HIV-infected patients in Argentina
European clinical guidelines for Tourette syndrome and other tic disordersâversion 2.0. Part III: pharmacological treatment
In 2011, the European Society for the Study of Tourette Syndrome (ESSTS) published the first European guidelines for Tourette Syndrome (TS). We now present an update of the part on pharmacological treatment, based on a review of new literature with special attention to other evidence-based guidelines, meta-analyses, and randomized double-blinded studies. Moreover, our revision took into consideration results of a recent survey on treatment preferences conducted among ESSTS experts. The first preference should be given to psychoeducation and to behavioral approaches, as it strengthens the patientsâ self-regulatory control and thus his/her autonomy. Because behavioral approaches are not effective, available, or feasible in all patients, in a substantial number of patients pharmacological treatment is indicated, alone or in combination with behavioral therapy. The largest amount of evidence supports the use of dopamine blocking agents, preferably aripiprazole because of a more favorable profile of adverse events than first- and second-generation antipsychotics. Other agents that can be considered include tiapride, risperidone, and especially in case of co-existing attention deficit hyperactivity disorder (ADHD), clonidine and guanfacine. This view is supported by the results of our survey on medication preference among members of ESSTS, in which aripiprazole was indicated as the drug of first choice both in children and adults. In treatment resistant cases, treatment with agents with either a limited evidence base or risk of extrapyramidal adverse effects might be considered, including pimozide, haloperidol, topiramate, cannabis-based agents, and botulinum toxin injections. Overall, treatment of TS should be individualized, and decisions based on the patientâs needs and preferences, presence of co-existing conditions, latest scientific findings as well as on the physicianâs preferences, experience, and local regulatory requirements
- âŠ