4,274 research outputs found
Superoxide dismutase analog (Tempol: 4-hydroxy-2, 2, 6, 6-tetramethylpiperidine 1-oxyl) treatment restores erectile function in diabetes-induced impotence.
We hypothesized that the administration of the superoxide dismutase (SOD) mimetic Tempol (4-hydroxy-2, 2, 6, 6-tetramethylpiperidine 1-oxyl) may reverse diabetes-induced erectile dysfunction. To test this hypothesis, reactive oxygen species-related genes (SOD1, SOD2, GP x 1, CAT, NOS2, NOS3) were tested, erectile functional studies and immunohistochemical analysis were carried out in diabetic rats treated with or without Tempol. Thirty Sprague-Dawley (3-4 months old) rats were divided into three groups (n=10 each), 20 with diabetes (diabetic control and Tempol treatment) and 10 healthy controls. At 12 weeks after the induction of diabetes by streptozotocin and Tempol treatment, all groups underwent in vivo cavernous nerve stimulation. Rat crura were harvested and the expression of antioxidative defense enzymes were examined by semi-quantitative reverse transcriptase PCR (RT-PCR). To confirm the RT-PCR results, we carried out immunohistochemistry (IHC) for catalase (CAT) and iNOS (NOS2). Nitration of tyrosine groups in proteins was also examined by IHC. Mean intracavernous pressure in the diabetic group was significantly lower than in the healthy controls (P <0.001) and was reversed by Tempol treatment (P <0.0108). NOS2 protein expression was significantly increased in diabetic animals compared with healthy controls and Tempol restored NOS2 protein level. Nitrotyrosine was also higher in diabetic animals and although Tempol treatment decreased its formation, it remained higher than that found in healthy controls. This study suggests that Tempol treatment increased erectile function through modulating oxidative stress-related genes in diabetic rats. This is the first report about the relationship between diabetes-induced erectile dysfunction and oxidative stress, and antioxidative therapy using the superoxide dismutase mimetic, Tempol, to restore erectile function
The Earth Effect in the MSW Analysis of the Solar Neutrino Experiments
We consider the Earth effect in the MSW analysis of the Homestake,
Kamiokande, GALLEX, and SAGE solar neutrino experiments. Using the
time-averaged data and assuming two-flavor oscillations, the large-angle region
of the combined fit extends to much smaller angles (to ) than when the Earth effect is ignored. However, the additional constraint
from the Kamiokande II day-night data excludes most of the parameter space
sensitive to the Earth effect independent of astrophysical uncertainties, and
leaves only a small large-angle region close to maximal mixing at 90\% C.L. The
nonadiabatic solution remains unaffected by the Earth effect and is still
preferred. Both theoretical and experimental uncertainties are included in the
analysis.Comment: (11 pages, Revtex 3.0 (can be changed to Latex), 3 postscript figures
included, UPR-0570T
A Common Explanation for the Atmospheric, Solar-Neutrino and Double Beta Decay Anomalies
We make a number of small changes, including correcting an error in our
heavy-neutrino decay rate. None of our analysis is changed, either in substance
or detail.Comment: 25 pages, 6 Figures, McGill-93/1
Current Status of the Solar Neutrino Problem with Super-Kamiokande
We perform an updated model-independent analysis using the latest solar
neutrino data obtained by Cl and Ga radiochemical experiments,
and most notably by a large water-Cherenkov detector SuperKamiokande with their
504 days of data taking. We confirm that the astrophysical solutions to the
solar neutrino problem are extremely disfavored by the data and a
low-temperature modification of the standard solar model is excluded by more
than 5 . We also propose a new way of illuminating the suppression
pattern of various solar neutrino flux without invoking detailed flavor
conversion mechanisms. It indicates that the strong suppression of Be
neutrinos is no more true when the neutrino flavor conversion is taken into
account.Comment: RevTex file, 10 pages, 7 postscript figure
Oscillations of Pseudo-Dirac Neutrinos and the Solar Neutrino Problem
The oscillations of pseudo-Dirac neutrinos in matter are discussed and
applied to the solar neutrino problem. Several scenarios such as both
and being pseudo-Dirac and only or being
pseudo-Dirac are examined. It is shown that the allowed region in the
mass-mixing angle parameter space obtained by comparing the solar neutrino data
with the calculations based on the standard solar model and the MSW effect is
not unique. The results depend on the nature of neutrinos; for example, if both
and are pseudo-Dirac, the allowed region determined by the
current solar neutrino data does not overlap with that obtained in the usual
case of pure Dirac or Majorana neutrinos.Comment: 12 pages, 2 figures (not included
Solar Neutrinos: Radiative Corrections in Neutrino-Electron Scattering Experiments
Radiative corrections to the electron recoil-energy spectra and to total
cross sections are computed for neutrino-electron scattering by solar
neutrinos. Radiative corrections change monotonically the electron recoil
spectrum for incident \b8 neutrinos, with the relative probability of observing
recoil electrons being reduced by about 4 \% at the highest electron energies.
For and \be7 neutrinos, the recoil spectra are not affected
significantly. Total cross sections for solar neutrino-electron scattering are
reduced by about 2 \% compared to previously computed values. We also calculate
the recoil spectra from N and O neutrinos including radiative
corrections.Comment: 40 pages, uuencoded, Z-compress file
Energy-dependent solar neutrino flux depletion in the Exact Parity Model and implications for SNO, SuperKamiokande and BOREXINO
Energy-dependent solar neutrino flux reduction caused by the
Mikheyev-Smirnov-Wolfenstein (MSW) effect is applied to the Exact Parity Model.
Several scenarios are possible, depending on the region of parameter space
chosen. The interplay between intergenerational MSW transitions and vacuum
``intragenerational'' ordinary-mirror neutrino oscillations is discussed.
Expectations for the ratio of charged to neutral current event rates at the
Sudbury Neutrino Observatory (SNO) are estimated. The implications of the
various scenarios for the Boron neutrino energy spectrum and BOREXINO are
briefly discussed. The consequences of MSW-induced solar neutrino depletion
within the Exact Parity Model differ in interesting ways from the standard
and cases. The physical causes of
these differences are determined.Comment: 43 pages, 8 figures, RevTeX; to appear in Phys. Rev. D, accepted
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