Buy sildenafil

Mary’s Hospital, Manchester, gave approval for this work, and consent was obtained for all tissue samples used in the study. The investigation conforms to the principles outlined in the Declaration of Helsinki ( 30).

Myometrial biopsies were obtained at delivery by cesarean section from the upper lip of the

lower

IBR is a correction of birthweight for known confounding variables and relates to a predicted birthweight calculated

using

Arginine vasopressin (AVP) and bradykinin (BK) were obtained from Sigma-Aldrich.

The thromboxane mimetic U46619 was obtained from Calbiochem (Nottingham, UK).

The PDE5 inhibitors sildenafil citrate (Viagra) and UK-343664 were obtained from Pfizer (Sandwich, UK).

Biopsies were placed directly into ice-cold physiological salt solution, a modified Krebs solution (see below for chemical composition).

Myometrial small arteries were identified and dissected under a stereomicroscope.

Myometrial artery diameters were 379 ± 4 ?m for NP biopsies (n = 49 arteries from 27 patients) and 310 ± 2 ?m for FGR biopsies (n = 62 arteries from 12 patients). Myometrial small arteries were carefully cut into small (approximately 2 mm) lengths and mounted onto 40-?m steel wire in a Danish Myo Technology (Aarhus, Denmark) M610 wire myograph as described elsewhere ( 32). Myometrial arteries were normalized to 0.9 of L 13.3kPa using the classical normalization procedure ( 33) as we have described in detail elsewhere ( 32, 34).

Initially, the bath contained 7 ml of physiological salt solution (in mmol/liter: 127.76 NaCl, 25 NaHCO 3 , 4.69 KCl, 2.4 MgSO 4 , 1.6 CaCl 2 , 1.18 KH 2 PO 4 , 6.05 glucose, 0.034 EDTA; pH 7.4), warmed to 37 C and gassed with air/5%CO 2 .

Contraction/relaxation responses of myometrial small arteries.

Dose-response constriction curves to AVP (0.1–10 nmol/liter; 2-min intervals) or the thromboxane-mimetic U46619 (0.1–1000 nmol/liter; 2-min intervals) were constructed followed by relaxation to BK (0.1–1000 nmol/liter; 2-min intervals).

Vessels were washed to baseline tension and then incubated for 1 h in the presence of 0, 10, or 100 nmol/liter of the PDE5 inhibitor sildenafil citrate or UK-343664. The protocol of constriction to AVP or U46619/relaxation to BK was repeated as outlined above in the maintained presence of the PDE5 inhibitor.

Data were first tested whether they fitted to a Gaussian (normal) distribution using the Kolmogorov-Smirnov test. Data that passed the normality test were compared

using

All other data were compared using nonparametric statistical tests (Mann-Whitney U test) and are presented as median-range. The effect of PDE5 incubation on agonist-induced constriction of myometrial small arteries was compared by paired t test.

BK-induced relaxation buy sildenafil of myometrial small arteries was compared using repeated-measures ANOVA. Data for the number of patients are indicated by (N). Women whose pregnancies were complicated by FGR delivered significantly earlier in gestation than the NP group ( P TABLE 1. NP 27 30 (19–40) 2 (1–5) 1 (0–4) 123 (110–150) 75 (60–85) 38.9 (37.4–41.5) 3300 (2690–4110) 46 (7–88) FGR 12 28.5 (22–37) 3.5 (1–5) 1 (0–4) 120 (115–140) 81 (70–90) 37.9 (29.8–39.0) a 2460 (745–2860) b 3 (0–5) b.

NP 27 30 (19–40) 2 (1–5) 1 (0–4) 123 (110–150) 75 (60–85) 38.9 (37.4–41.5) 3300 (2690–4110) 46 (7–88) FGR 12 28.5 (22–37) 3.5 (1–5) 1 (

0–4

Demographic and clinical details are given for NP women and women whose pregnancies were complicated by FGR.

All data are median with range in parentheses for maternal age at delivery, gravidity, parity, maximum attained blood pressure (BP), gestation at delivery, birthweight, and IBR. Groups were compared statistically using the Mann-Whitney U test.

NP 27 30 (19–40) 2 (1–5) 1 (0–4) 123 (110–150) 75 (60–85) 38.9 (37.4–41.5) 3300 (2690–4110) 46 (7–88) FGR 12 28.5 (22–37) 3.5 (1–5) 1 (0–4) 120 (115–140) 81 (70–90) 37.9 (29.8–39.0) a 2460 (745–2860) b 3 (0–5) b. NP 27 30 (19–40) 2 (1–5) 1 (0–4) 123 (110–150) 75 (60–85) 38.9 (37.4–41.5) 3300 (2690–4110) 46 (7–88) FGR 12 28.5 (22–37) 3.5 (1–5) 1 (0–4) 120 (115–140) 81 (70–90) 37.9 (29.8–39.0) a 2460 (745–2860) b 3 (0–5) b. Demographic and clinical details are given for NP women and women whose pregnancies were complicated by FGR.

All data are median with range in parentheses for maternal age at delivery, gravidity, parity, maximum attained blood pressure (BP), gestation at delivery, birthweight, and IBR. Groups were compared statistically using the Mann-Whitney U test.

Small arteries from women whose pregnancies were complicated by FGR showed significantly increased vasoconstriction compared with that seen in small arteries taken from NP women ( P 0.05, t test). Addition of AVP to myometrial small arteries from women with FGR evoked maximal constriction of 21.5 ± 0.4 kPa (n = 24 arteries from seven patients) compared with 16.7 ± 0.4 kPa (n = 22 arteries from seven patients) in NP women ( P = 0.06, t test).

However, the sensitivity of myometrial small arteries from women whose pregnancies were complicated by FGR to AVP-induced vasoconstriction was not significantly altered compared with vessels from NP women (EC 50 , 0.47 ± 0.15 nmol/liter in FGR vs . These data suggest modified vasoconstriction of myometrial small arteries from women whose pregnancies are complicated by FGR. Effect of U46619 and AVP on myometrial small arteries from NP women and women whose pregnancies are complicated by FGR. Data are expressed as active effective pressure production in kPa. All data are mean ± sem ; the x axis shows concentration of agonist ? 10 ?x .

?, NP (n = 13, top ; n = 14, bottom ); ?, FGR pregnancy (n = 10, top ; n = 6, bottom ). Effect of U46619 and AVP on myometrial small arteries from NP women and women whose pregnancies are complicated by FGR. Data are expressed as active effective pressure production in kPa. All data are mean ± sem ; the x axis shows concentration of agonist ? 10 ?x . ?, NP (n = 13, top ; n = 14, bottom ); ?, FGR pregnancy (n = 10, top ; n = 6, bottom ). The effect of PDE5 inhibition on agonist-induced vasoconstriction is shown in Table 2. In NP, myometrial small arteries incubated with 100 nmol/liter sildenafil showed decreased constriction to AVP ( P = 0.002, paired t test). A similar trend was seen in vessels constricted with U46619, although this did not achieve statistical significance ( P = 0.14, paired t test). In women with pregnancies complicated by FGR, myometrial small arteries incubated with

100

Effect of incubation with sildenafil citrate on agonist-induced constriction of myometrial small arteries. U46619 0 10.6 ± 1.0 (7) 10.7 ± 0.9 0.97 23.6 ± 1.3 (10) 22.2 ± 1.2 0.43 10 14.9 ± 1.1 (7) 12.9 ± 1.3 0.06 17.3 ± 0.8 (7) 15.7 ± 0.8 0.16 100 15.5 ± 0.6 (13) 14.5 ± 0.7 0.14 19.4 ± 0.7 (13) 17.2 ± 0.7 0.002 AVP 0 17.8 ± 1.0 (7) 16.0 ± 1.2 0.24 22.7 ± 1.0 (7) 23.2 ± 1.0 0.33 10 14.0 ± 0.9 (7) 12.3 ± 1.1 0.22 16.5 ± 0.9 (7) 14.9 ± 1.0 0.04 100 16.7 ± 1.2 (8) 14.0 ± 1.1 0.002 24.1 ± 1.0 (10) 20.8 ± 1.8 0.05.

U46619 0 10.6 ± 1.0 (7) 10.7 ± 0.9 0.97 23.6 ± 1.3 (10) 22.2 ± 1.2 0.43 10 14.9 ± 1.1 (7) 12.9 ± 1.3 0.06 17.3 ± 0.8 (7) 15.7 ± 0.8 0.16 100 15.5 ± 0.6 (13) 14.5 ± 0.7 0.14 19.4 ± 0.7 (13) 17.2 ± 0.7 0.002 AVP 0 17.8 ± 1.0 (7) 16.0 ± 1.2 0.24 22.7 ± 1.0 (7) 23.2 ± 1.0 0.33 10 14.0 ± 0.9 (7) 12.3 ± 1.1 0.22 16.5 ± 0.9 (7) 14.9 ± 1.0 0.04 100 16.7 ± 1.2 (8) 14.0 ± 1.1 0.002 24.1 ± 1.0 (10) 20.8 ± 1.8 0.05.

Data are expressed as active effective pressure production (kPa). Data at each concentration of PDE5 inhibitor were compared before and after PDE5 inhibitor using the paired Student’s t test.

Effect of incubation with sildenafil citrate on agonist-induced constriction of myometrial small arteries.

U46619 0 10.6 ± 1.0 (7) 10.7 ± 0.9 0.97 23.6 ± 1.3 (10) 22.2 ± 1.2 0.43 10 14.9 ± 1.1 (7) 12.9 ± 1.3 0.06 17.3 ± 0.8 (7) 15.7 ± 0.8 0.16 100 15.5 ± 0.6 (13) 14.5 ± 0.7 0.14 19.4 ± 0.7 (13) 17.2 ± 0.7 0.002 AVP 0 17.8 ± 1.0 (7) 16.0 ± 1.2 0.24 22.7 ± 1.0 (7) 23.2 ± 1.0 0.33 10 14.0 ± 0.9 (7) 12.3 ± 1.1 0.22 16.5 ± 0.9 (7) 14.9 ± 1.0 0.04 100 16.7 ± 1.2 (8) 14.0 ± 1.1 0.002 24.1 ± 1.0 (10) 20.8 ± 1.8 0.05.

U46619 0 10.6 ± 1.0 (7) 10.7 ± 0.9 0.97 23.6 ± 1.3 (10) 22.2 ± 1.2 0.43 10 14.9 ± 1.1 (7) 12.9 ± 1.3 0.06 17.3 ± 0.8 (7) 15.7 ± 0.8 0.16 100 15.5 ± 0.6 (13) 14.5 ± 0.7 0.14 19.4 ± 0.7 (13) 17.2 ± 0.7 0.002 AVP 0 17.8 ± 1.0 (7) 16.0 ± 1.2 0.24 22.7 ± 1.0 (7) 23.2 ± 1.0 0.33 10 14.0 ± 0.9 (7) 12.3 ± 1.1 0.22 16.5 ± 0.9 (7) 14.9 ± 1.0 0.04 100 16.7 ± 1.2 (8) 14.0 ± 1.1 0.002 24.1 ± 1.0 (10) 20.8 ± 1.8 0.05.

Data are expressed as active effective pressure production (kPa). Data at each concentration of PDE5 inhibitor were compared before and after PDE5 inhibitor using the paired Student’s t test. Wire myography: relaxation responses of small arteries from myometrium.

Alteration of endothelial function in pregnancies complicated by FGR.

U46619-constricted myometrial small arteries from NP women

exhibited

This relaxation was significantly attenuated in arteries from women whose pregnancies were complicated by FGR (residual constriction, 43 ± 8% in FGR vs .

30 ± 5% in NP; IC 50 , 84 ± 15 nmol/liter in FGR vs .

14 ± 9 nmol/liter in NP; P = 0.001, repeated-measures ANOVA).

A similar relationship was seen with arteries constricted with AVP (residual constriction, 45 ± 12% in FGR vs . 80 ± 3% in NP; IC 50 , 21 ± 12 nmol/liter in FGR vs .

15 ± 7

nmol/liter

Data are expressed as percent maximal response to U46619.

All data are mean ± sem ; x axis shows concentration of BK ? 10 ?x . Top , Arteries from NP (?; n = 14) and arteries from FGR pregnancy (?; n = 16 vessels from 12 patients); bottom , arteries from FGR pregnancy, BK-only control (•; n = 10), and arteries from FGR pregnancy, BK with 100 nmol/liter sildenafil citrate (0; n = 10). Data were compared before and after sildenafil by repeated-measures ANOVA.

Endothelium-dependent relaxation of U46619-constricted myometrial small arteries.

Data are expressed as percent maximal response to U46619.

All data are mean ± sem ; x axis shows concentration of BK ? 10 ?x .

Top , Arteries from NP (?; n = 14) and arteries from FGR pregnancy (?; n = 16 vessels from 12 patients); bottom , arteries from FGR pregnancy, BK-only control (•; n = 10), and arteries from FGR pregnancy, BK with 100 nmol/liter sildenafil citrate (0; n = 10). Data were compared before and after sildenafil by repeated-measures ANOVA.

Endothelium-dependent relaxation of AVP-constricted myometrial small arteries.

Data are expressed as percent maximal response to AVP. All data are mean ± sem ; x axis shows concentration of BK ? 10 ?x . Top , Arteries from NP (?; n = 14) and arteries from FGR pregnancy (?; n = 8); bottom , arteries from FGR pregnancy, BK-only control (•; n = 6), and arteries from FGR pregnancy, BK with 100 nmol/liter sildenafil citrate (0; n = 6).

Data were compared before and after sildenafil by repeated-measures ANOVA. Endothelium-dependent relaxation of AVP-constricted myometrial small arteries.

Data are expressed as percent maximal response to AVP. All data are mean ± sem ; x axis shows concentration of BK ? 10 ?x . Top , Arteries from NP (?; n = 14) and arteries from FGR pregnancy (?; over the counter sildenafil cvs n = 8); bottom , arteries from FGR pregnancy, BK-only control (•; n = 6), and arteries from FGR pregnancy, BK with 100 nmol/liter sildenafil citrate (0; n = 6).

Data were compared before and after sildenafil by repeated-measures ANOVA. The effect of PDE5 inhibition on human myometrial small arteries was studied using U46619- and AVP-induced constriction.

BK-induced relaxation of myometrial small arteries from NP women, preconstricted with U46619, was not significantly altered by preincubation with 0, 10, or 100 nmol/liter sildenafil [residual constriction, 30 ± 9% (control) vs .

35 ± 8% (10 nmol/liter) and 30 ± 5% (100 nmol/liter); n = 10; P > 0.05, repeated-measures ANOVA]. Similar data were seen when AVP (n = 7) was used to constrict arteries from NP women [residual constriction, 16 ± 3% (control) vs .

27 ± 9% (10 nmol/liter) and 28 ± 9% (100 nmol/liter); n = 7; P > 0.05, repeated-measures ANOVA].

In U46619-constricted arteries from women whose pregnancies were complicated by FGR, preincubation with sildenafil enhanced BK-induced relaxation [residual constriction, 40 ± 10% (control) vs . 47 ± 11% (10 nmol/liter) and 22 ± 10% (100 nmol/liter)]. This improvement in relaxation attained significance at 100 nmol/liter (IC 50 , 20 ± 9 nmol/liter (100 nmol/liter) vs . In AVP-constricted arteries from women whose pregnancies were complicated by FGR, preincubation with sildenafil enhanced BK-induced relaxation [residual constriction, 49 ± 14% (control) vs .

39 ± 14% (10 nmol/liter) and 34 ± 14% (100 nmol/liter)].

This improvement in relaxation attained significance at 100 nmol/liter

[IC

In U46619-constricted arteries from women whose pregnancies were complicated by FGR, preincubation with 100 nmol/liter of the related PDE5 inhibitor UK-343664, also significantly enhanced relaxation [IC 50 , 10 ± 7 nmol/liter (100 nmol/liter) vs .

Endothelium-dependent relaxation of U46619-constricted myometrial small arteries.

Data are expressed as percent maximal response to U46619.

All data are mean ± sem ; x axis is concentration of BK ? 10 ?x . Arteries are from FGR pregnancy, BK-only control (?; n = 6), and from FGR pregnancy, BK

with

Data were compared before and after UK-343664 by repeated-measures ANOVA. Endothelium-dependent relaxation of U46619-constricted myometrial small arteries.

Data are expressed as percent maximal response to U46619.

All data are mean ± sem ; x axis is concentration of BK ? 10 ?x .

Arteries are from FGR pregnancy, BK-only control (?; n = 6), and from FGR pregnancy, BK with 100 nmol/liter UK-343664 (?; n = 6).