1,583 research outputs found
Testosterone Increases: Sodium Reabsorption, Blood Pressure, and Renal Pathology in Female Spontaneously Hypertensive Rats on a High Sodium Diet
Estrogen (E) and testosterone (T) are important in the sexually dimorphic pattern of blood pressure (BP) development. The goal was to examine the effects of endogenous E and exogenous T in the development of hypertension in female spontaneously hypertensive rats (SHR) on a high sodium diet. Female SHR (N = 27, 5-week) were divided into four groups: (1) control (n = 8), (2) ovariectomized (OVX, n = 26), (3) testosterone implants with intact ovaries (T, n = 6), and (4) ovariectomized + testosterone implants (OVX+T, n = 7). T was given immediately after OVX and replaced every two weeks and they were fed a 3% NaCl diet. BP was measured weekly and plasma norepinephrine (NE) analyzed by HPLC. OVX+T females exhibited the greatest elevation in BP
(190 ± 4.0 mmHg) compared to controls at 15 weeks of age
(140 ± 3.4 mmHg, P < .001) and a pattern of hypertension development similar to that of male SHR. Females with T treatment showed evidence of glomerulosclerosis. In conclusion, T accelerated the development of hypertension similar to the BP pattern observed in males; the presence of ovaries attenuated the T induced increase in BP; T increased renal sodium reabsorption, and T increased glomerulosclerosis
Search for Compensated Isocurvature Perturbations with Planck Power Spectra
In the standard inflationary scenario, primordial perturbations are
adiabatic. The amplitudes of most types of isocurvature perturbations are
generally constrained by current data to be small. If, however, there is a
baryon-density perturbation that is compensated by a dark-matter perturbation
in such a way that the total matter density is unperturbed, then this
compensated isocurvature perturbation (CIP) has no observable consequence in
the cosmic microwave background (CMB) at linear order in the CIP amplitude.
Here we search for the effects of CIPs on CMB power spectra to quadratic order
in the CIP amplitude. An analysis of the Planck temperature data leads to an
upper bound , at the 68\% confidence
level, to the variance of the CIP amplitude. This is then
strengthened to if Planck
small-angle polarization data are included. A cosmic-variance-limited CMB
experiment could improve the sensitivity to CIPs to . It is also found that adding CIPs to the
standard CDM model can improve the fit of the observed smoothing of
CMB acoustic peaks just as much as adding a non-standard lensing amplitude.Comment: 9 Pages, 3 Tables, 6 Figures. Accepted in PR
Hypertension in the Spontaneously Hypertensive Rat is Linked to the Y-Chromosome
The objective of our study was to determine the genetic influence on blood pressure in spontaneously hypertensive rats (SHR), and normotensive Wistar-Kyoto (WKY) rats using genetic crosses. Blood pressure was measured by tail sphygmomanometry from 8 to 20 weeks of age. Blood pressure was significantly higher from 12 to 20 weeks in the male offspring derived from WKY mothers x SHR fathers as compared with male offspring derived from SHR mothersxWKY fathers (180±4 versus 160±5 mm Hg, /?\u3c0.01). There was no significant difference between the blood pressure of the F, females, further supporting Y chromosome linkage and not parental imprinting. The blood pressure data from F2 males derived from reciprocal crosses of parental strains were consistent with the presence of a Y-Iinked locus, but not with an X-linked locus controlling blood pressure. The data strongly suggest that hypertension in the SHR has two primary components of equal magnitude, one consisting of a small number of autosomal loci with a second Y-linked component
Overbooking
We consider optimal pricing policies for airlines when passengers are uncertain at the time of ticketing of their eventual willingness to pay for air travel. Auctions at the time of departure efficiently allocate space and a profit maximizing airline can capitalize on these gains by overbooking ights and repurchasing excess tickets from those passengers whose realized value is low. Nevertheless profit maximization entails distortions away from the efficient allocation. Under regularity conditions, we show that the optimal mechanism can be implemented by a modified double auction. In order to encourage early booking, passengers who purchase late are disadvantaged. In order to capture the information rents of passengers with high expected values, ticket repurchases at the time of departure are at a subsidized price, sometimes leading to unused capacity
Separate Sex-Influenced and Genetic Components in Spontaneously Hypertensive Rat Hypertension
Previous results from our laboratory indicated two major genetic components of spontaneously hypertensive rat (SHR) hypertension, an autosomal component and a Y chromosome component. Two new substrains, SHR/a and SHR/y, were developed using a series of backcrosses to isolate each of these components. The SHR/a substrain has the autosomal loci and X chromosome from the SHR strain and the Y chromosome from the Wistar-Kyoto (WKY) rat strain. The SHR/y substrain has only the Y chromosome from the SHR and autosomal loci and X chromosome from the WKY strain. Throughout these breeding programs parents were chosen at random without selection for blood pressure. Males of both substrains maintained blood pressures over 180 mm Hg. Comparisons of blood pressure in these new substrains with the original parental strains can be used to determine the relative proportions of each genetic component in hypertension. The Y chromosome component contributes 34 mm Hg, which is the difference between SHR/y male and WKY male blood pressure. The total autosomal component contributes 46 mm Hg, which is the difference between SHR/a male and WKY male blood pressure. The autosomal component is a sex-influenced trait; males in the SHR/a strain have significantly higher pressures than SHR/a females. Of the 46 mm Hg estimated for the autosomal component, 41 mm Hg is the result of these loci interacting with male phenotypic sex. This sex-influenced component is separate and distinct from the Y chromosome component
Genetic-Divergence Between the Wistar-Kyoto Rat and the Spontaneously Hypertensive Rat
A method of restriction fragment length polymorphism (RFLP) analysis was used to estimate the amount of genetic divergence between the spontaneously hypertensive rat (SHR) strain and the Wistar-Kyoto (WKY) strain. DNA from each strain was digested with eight restriction endonucleases and hybridized with six single copy gene sequences. The number of hybridization bands in each digestion was used to estimate the total number of bases analyzed and RFLPs were scored as single mutations. Divergence was then estimated by dividing the number of mutations by the number of bases analyzed. In a total of 808 bases analyzed in WKY rats, a minimum of 13 mutations were scored in SHR, which yields a nucleotide divergence of 1 change per 62 bp. This is an extremely high amount of divergence given the known origin of these two strains and is comparable to the maximum divergence possible between unrelated humans
Testosterone Effects On Renal Norepinephrine Content and Release in Rats With Different Y Chromosomes
The Y chromosome in spontaneously hypertensive rats (SHR) and stroke-prone rats has been shown to contain a locus that contributes to the hypertensive effect; both the sympathetic nervous system and testosterone may be involved. The objective of this study was to look at the effects of testosterone on renal norepinephrine (NE) release and content in the isolated perfused kidney in different Y chromosome backgrounds. The study involved male SHR, Wistar-Kyoto rats (WKY), and 2 consomic strains with different Y chromosomes (n=5 to 8 per group). Adult animals were castrated, and implants containing testosterone propionate were placed at the base of the neck. Blood testosterone levels were measured by radioimmunoassay 2 weeks after castration. The left kidney was isolated and perfused with oxygenated Krebs solution at a constant flow and temperature with KCl and electrical stimulation of the renal nerves. Perfusate was collected and analyzed for NE by high-performance liquid chromatography. Lactate dehydrogenase analyses were performed as a marker for potential tissue damage. Renal perfusate and renal tissue NE levels were significantly elevated by testosterone. The average NE increase with a single testosterone implant was 13.2 ng/mL, and for a double testosterone implant it was 29.8 ng/mL. The Y chromosome from the SHR produced a significant increase in renal NE release compared with the WKY Y chromosome. Significance was shown between all groups: 1 versus 2 implants, P=0.0067; 1 versus sham implants, P=0.015; 2 versus sham implants,
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Fast Moment Estimation in Data Streams in Optimal Space
We give a space-optimal streaming algorithm with update time for approximating the pth frequency moment, 0 < p < 2, of a length-n vector updated in a data stream up to a factor of . This provides a nearly exponential improvement over the previous space optimal algorithm of [Kane-Nelson-Woodruff, SODA 2010], which had update time . When combined with the work of [Harvey-Nelson-Onak, FOCS 2008], we also obtain the first algorithm for entropy estimation in turnstile streams which simultaneously achieves near-optimal space and fast update time.Engineering and Applied Science
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