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Query: UMLS:C0432222 (SEM)
 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We examined the sensitivity of lymphocytes from different age groups to inhibition by prostaglandin E2. Phytohemagglutinin-stimulated cultures of peripheral blood mononuclear cells from 12 healthy subjects over the age of 70 were much more sensitive to inhibition by exogenously added prostaglandin E2 than were cells from 17 young controls (ID50 congruent to 10 nM for the subjects over 70 vs. greater than 3 micronM for the young controls). The more senstivie lymphocytes from a subject over 70 were to prostaglandin E2, the lower was his or her response to phytohemagglutinin (r = 0.75, P less than 0.01). The mean responses to phytohemagglutinin of the peripheral blood mononuclear cells from the subjects over 70 were significantly depressed compared to the young controls. Addition of indomethacin, a prostaglandin synthetase inhibitor, to the cultures resulted in an increase in [3H]thymidine incorporation of 140 +/- 16% in the cells of the subjects over 70 vs. a 36 +/- 3% increase in the young controls (mean +/- SEM, P less than 0.001). The mean phytohemagglutinin response of the subjects over 70 was 40% of the control response without indomethacin. With addition of indomethacin the response of subjects over 70 rose to 72% of control. Thus, increased sinsitivity to prostaglandin E2 appears to be responsible in part for the depressed mitogen response of peripheral blood mononuclear cells from healthy subjects over 70.
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PMID:Sensitivity of lymphocytes to prostaglandin E2 increases in subjects over age 70. 45 62

Urinary excretion of prostaglandin E was measured in seven sick low-birth-weight infants. Four had severe hyaline membrane disease and one had chronic bronchopulmonary dysplasia; all received furosemide. Two infants had patent ductus arteriosus and received indomethacin. Following administration of furosemide, urine volume and the excretion rates of sodium and calcium were significantly increased; such changes were not seen following the administration of indomethacin. Prostaglandin E excretion rate was increased from 0.4 +/- 0.04 to 1.3 +/- 0.2 ng/mg Cr (mean +/- SEM) following administration of furosemide, but decreased in two patients following administration of indomethacin. The present results demonstrate that furosemide enhances urinary excretion of prostaglandin E by mechanisms which may reflect an increase in prostaglandin synthesis, a decrease in prostaglandin renal metabolism, or both. Indomethacin, which is a prostaglandin synthetase inhibitor, decreases the urinary excretion of prostaglandin E. These observations suggest that furosemide therapy in patients receiving indomethacin may be ineffective.
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PMID:Urinary excretion of prostaglandin E following the administration of furosemide and indomethacin to sick low-birth-weight infants. 69 Jul 80

Experiments were performed to evaluate the role of prostaglandin synthesis in the regulation of coronary blood flow in dog hearts. The left main coronary artery was cannulated and flow measured both in otherwise intact animals and in canine heart-lung preparations. Prostaglandin E was measured by radioimmunoassay. Reactive hyperemia (flow after occlusion release) was induced by coronary occlusion for 10, 15, and 20 s and was 39 plus or minus 13 (mean plus or minus SEM), 66 plus or minus 21, and 82 plus or minus 24 ml, respectively. Indomethacin, an inhibitor of prostaglandin synthetase, reduced reactive hyperemia at 10, 15, and 20 s to 15 plus or minus 5, 33 plus or minus 11, and 47 plus or minus 17 ml, respectively (P smaller than 0.05). Meclofenamate, a different prostaglandin synthetase inhibitor, gave similar results. In a second group of five dogs, prostaglandin production of the heart was examined in response to 20-s occlusions. There was a significant increase in prostaglandin production from a basal level of 18.6 plus or minus 4.9 mg/min to 35.3 plus or minus 5.8 ng/min after occlusion of the coronary artery for 20 s (P smaller than 0.05). After indomethacin, this increase in prostaglandin production was not observed and reactive hyperemia was significantly reduced. Thus, prostaglandin synthesis appears to be important to modulating canine coronary blood flow in response to brief periods of coronary occlusion.
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PMID:Regulation of postocclusive hyperemia by endogenously synthesized prostaglandins in the dog heart. 80 95

The role of prostaglandins in blood pressure regulation was studied in normal rats and in animals with renal artery constriction. The effects of chronic inhibition of prostaglandin (PG) synthesis on arterial pressure were observed, and renal medullary PG synthesis was measured in vitro. The prostaglandin synthetase inhibitor indomethacin was given in a dose of 2 mg/kg/day by mouth to one of two groups of male Wistar rats with a unilateral renal artery constriction and the other kidney untouched, and to one of two sham-clipped groups. Systolic blood pressures were higher in indomethacin-treated clipped rats than in non-indomethacin-treated clipped animals, and at 18 days averaged 188 mm Hg (plus or minus SEM 5.9, n = 36) and 162 mm Hg (plus or minus SEM 7.6, n = 34), respectively (P less than 0.005 for data pooled from two experiments). Indomethacin did not affect pressures of sham-clipped animals treated for 40 days. Analysis of PG synthesis by gas-liquid chromatography in renal medullary slices incubated for 30 minutes in Krebs-Henseleit buffer showed: (1) 40% suppression of PGE synthesis in hypertensive animals (P less than 0.001): (2) no differences between clipped and untouched kidneys; (3) chronic indomethacin treatment did not affect PGE synthesis in the in vitro buffer system; and (4) no PGA synthesis was detected. In a further experiment in which medullary slices were incubated in plasma of rats treated with equivalent doses of indomethacin, PGE synthesis was suppressed by 35%. The experiments support the concept that prostaglandins modulate pressor mechanisms which come into play when renal blood flow is drastically reduced. The effects could be mediated by PG synthesis in the kidney and/or in other systemic vascular beds.
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PMID:Renal prostaglandin synthesis in the Goldblatt hypertensive rat. 113 85

To investigate the effects of the prostaglandin synthetase inhibitor, meclofenamate, on postnatal ventilation, we studied 11 unanaesthetised, spontaneously-breathing lambs at an average age of 7.9 +/- 1.1 days (SEM; range 5-14 days) and an average weight of 4.9 +/- 0.5 kg (range 3.0-7.0 kg). After a 30-min control period we infused 4.23 mg/kg meclofenamate over 10 min and then gave 0.23 mg/h per kg for the remainder of the 4 h. Ventilation increased progressively from a control value of 515 +/- 72 ml/min per kg to a maximum of 753 +/- 100 ml/min per kg after 3h of infusion (P less than 0.05) due to an increased breathing rate; the effects were similar during both high- and low-voltage electrocortical activity. There were no significant changes in tidal volume, heart rate, blood pressure, arterial pH or PaCO2, the increased ventilation resulted from either an increase in dead space ventilation or an increase in CO2 production. This study indicates that meclofenamate causes an increase in ventilation in lambs but no changes in pH of PaCO2. The mechanism and site of action remain to be defined.
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PMID:Meclofenamate increases ventilation in lambs. 250 22

The rate of prostaglandin E (PGE) production was measured in collagenase-dispersed amniotic cells obtained from 14 women after spontaneous labour at term--seven after spontaneous preterm labour, nine after delivery by elective caesarean section at term and six after induction of labour at term. Cells were incubated with and without arachidonic acid and PGE was estimated by specific radioimmunoassay. Basal PGE output (pmol/10(6) cells per 3 h) was highest in the spontaneous labour group, 27.5 (SEM 5.5) and lowest in the preterm labour group, 4 (SEM 1.2) (P less than 0.001). Values in the elective section and induction groups were 13.6 (SEM 2.7) and 10 (SEM 3.1), respectively; these values were significantly higher than in the preterm labour group and the values after induction were significantly lower than after spontaneous labour. Addition of arachidonic acid resulted in a significant increase in PGE output in all groups, but the values after preterm labour remained significantly lower than those of any group at term. These data indicate that towards term there is a maturation in the PG synthetase activity of the amnion and that PGE output in this tissue is increased in spontaneous labour.
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PMID:Prostaglandin E production by amniotic cells in relation to term and preterm labour. 311 95

Plasma 17 beta-estradiol concentrations, thecal estrogen content, and uterine prostaglandin synthetase activity were measured in healthy and prolapsed hens as well as in layers that recovered after exposure to low intensity lighting (250 or 50 lx). The effect of estradiol benzoate injections (100 ng, 3 X per week) in hens exposed to high intensity light (greater than 500 lx) was also studied. Prolapsed hens had significantly lower plasma 17 beta-estradiol concentrations (60 +/- 12 pg/ml; mean +/- SEM) than recovered (374 +/- 40 pg/ml) or healthy hens (475 +/- 45 pg/ml). Theca cells from recovered hens had a significantly higher content of 17 beta-estradiol (.7 ng/5 X 10(5) cells) than theca cells from normal or prolapsed birds (.3 ng/5 X 10(5) cells). Microsomes prepared from the uteri of prolapsed hens converted significantly less arachidonic acid to prostaglandin metabolites (4.4%) than did microsomes from healthy or recovered birds (9.0%). Treatment of prolapsed hens with estradiol benzoate resulted in 89% of the birds recovering within 3 weeks compared to a 4% recovery rate in the controls. We conclude that restoration of peripheral 17 beta-estradiol concentrations to normal levels was concomitant with recovery in prolapsed birds, and suggest that the estrogen exerts its effect by raising the level of prostaglandin synthetase activity in the uterus.
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PMID:The role of 17 beta-estradiol in the recovery from oviductal prolapse in layers. 643 10

We have previously reported that hyperosmotic solutions of sodium chloride or of xylitol possess potent anti-ulcer activity and reduce gastric acidity in the rat. They also stimulate gastric prostaglandin (PG) biosynthesis, which may bear a causal relationship to the above effects. In the present investigation we studied the effect of intragastric hyperosmolarity on the transmucosal potential difference (PD) and on the permeability to H+ ions in the rat stomach. We also studied the effect of the prostaglandin synthetase inhibitors, indomethacin and flufenamic acid, on these parameters. Rat stomach was perfused in vivo, under urethane anesthesia, by xylitol solutions made up in 0.01 N HCl. While moderately hyperosmotic (13%) xylitol was without effect, the perfusion of intensely hyperosmotic xylitol (34.5%) resulted in a long lasting reduction of the transmucosal PD from a mean (+/- SEM) of -63 +/- 4 mV to a trough value of -40 +/- 3 mV. This depression of transmucosal PD was inhibited in a dose-related fashion by prior treatment with the PG-synthetase inhibitors. Acid recovery in the effluent was significantly reduced by the 34.5% xylitol solution and indomethacin pretreatment did not modify the effect of hyperosmotic xylitol. It is concluded that, although intensely hyperosmotic xylitol produces some of the characteristic effects of a barrier breaker, i.e. depression of transmucosal PD and acid back diffusion, these two phenomena probably involve different mechanisms, as indicated by their differential response to indomethacin.
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PMID:Hyperosmotic xylitol, prostaglandins and gastric mucosal barrier. 679 43

1. The effects of changes in sodium balance on renal prostaglandins have been hitherto studied mainly in experimental animals and the results have been controversial. In this study the 24 h urinary excretion of prostaglandins E2 and F2 alpha was measured by radioimmunoassay in seven normal subjects under basal conditions and after 5 days of a diet containing less than 20 mmol of sodium/day. Subsequently a sodium chloride (150 mmol/l: saline) load (300 mmol of sodium over 4 h) was infused and prostaglandins were again measured in hourly urine collections. Plasma renin activity and aldosterone were also measured under basal conditions, after the low sodium diet and at 2 and 4 h of the saline infusion. 2. Dietary sodium restriction was associated with a marked increase in prostaglandin E2 excretion (from 769.7 +/- 201.6 SEM to 1761.3 +/- 304.9 ng/24 h, P less than 0.0005). Prostaglandin F2 alpha also increased from 1187.0 +/- 390.1 to 1435.6 +/- 344.6 ng/24 h, but this was not statistically significant. The prostaglandin E2/prostaglandin F2 alpha ratio increased from 0.83 +/- 0.2 to 1.52 +/- 0.34 (P less than 0.01). Plasma renin activity and aldosterone rose significantly (P less than 0.05 and less than 0.0025 respectively). 3. During the saline load prostaglandin E2 decreased after 2 h from 142.4 +/- 29.9 to 86.7 +/- 22.9 ng/h (P less than 0.05) and to 36.9 +/- 5.96 ng/h after 4 h. Prostaglandin F2 alpha decreased at a slower rate, from 98.4 +/- 18.7 to 37.5 +/- 8.8 ng/h at 4 h (P less than 0.02). At 4 h the prostaglandin E2/prostaglandin F2 alpha ratio returned to control values (0.90 +/- 0.17). Plasma renin activity and aldosterone decreased significantly after 2 h (P less than 0.02 and less than 0.0025 respectively) and reached control values after 4 h. 4. The present study demonstrates that chronic and acute changes in sodium balance induce changes in the excretion of prostaglandin E2 parallel to changes in plasma renin activity and aldosterone. The similar but quantitatively smaller changes in prostaglandin F2 alpha and the inversion of the ratio between the two prostaglandins during sodium deprivation suggest that at least two factors are involved: increased delivery of substrate for prostaglandin synthase and decreased activity of the prostaglandin E1 9-keto-reductase. Prostaglandins probably play an important role in the adaptation of the kidney to changes in sodium balance.
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PMID:Effect of chronic and acute changes in sodium balance on the urinary excretion of prostaglandins E2 and F2 alpha in normal man. 701 97