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Query: UNIPROT:P01178 (oxytocin)
 15,767 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The various neurohumoral and intrinsic factors that control the uteroplacental hemodynamics in health and disease and in responses to physiologic and pharmacologic stimuli have been reviewed. The following conclusions may be derived: We still need improvement in our methodology of monitoring uterine blood flow. The present methods, which have some reliability, are not easily applicable to human subjects and even in animals their use presents problems of accuracy and sensitivity with which the investigator must become familiar. The marked and progressive increase in uterine blood flow that occurs during pregnancy is caused by complex factors, some of which are hormonal and hemodynamic in nature. The increased vascularity of the pregnant uterus and the opening of the arterioles during the process of formation of the intervillous space are important factors that facilitate the increase in uterine blood flow. The increment seems to be totally derived from the increment in the cardiac output that occurs during pregnancy. There seems to be no redistribution among the regional blood flows of the body. In the anesthetized condition the blood flow to the uterus depends largely on the perfusing pressure; the critical closing pressure seems to be around the 40 mm Hg level. This linear flow-pressure relationship does not, however, apply to the unanesthetized condition. A rise or fall in the perfusing pressure in the conscious state may be accompanied by an increase or decrease in the uterine blood flow, depending on the underlying mechanisms. Factors that lead to alpha-adrenergic stimulation produce an increase in uterine vascular resistance and a decrease in flow, irrespective of the status of the perfusing pressure. beta-adrenergic stimulation may increase uterine blood flow either through their vasodilating action or through their myometrial relaxing effects. Hypertensive diseases are most often accompanied by a decrease in uterine blood flow, whereas hypoxic states may decrease the flow even though the arterial pressure may not change significantly. It is extremely risky to extrapolate from information obtained in the anesthetized animal to the unanesthetized, conscious animal. Likewise, data obtained from normotensive conditions may not hold true for the hypertensive or hypotensive states. This is of particular relevance when one is dealing with the effects of pharmacologic agents that act on the cardiovascular system. Uterine contractions, whether induced through spontaneous or oxytocin-induced labor, produce a decrease in uterine blood flow.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Control of the uteroplacental circulation in health and disease. 4

Prostaglandins are highly potent derivatives of unsaturated fatty acids with multiple biological activities. They are synthesized and metabolized in almost all tissues studied so far. The E- und F-type prostaglandins may be regarded as local modulators of hormonal effects on cell function and--in some cases (kidney, uterus-corpus luteum)--as regional or tissue hormones. Thus they seem to be involved in the regulation of neurotransmission, kidney function, triglyceride metabolism in adipose tissue and progesterone biosynthesis. Apart from their influence on renal blood flow prostaglandins of the A-type possibly have an additional function as circulatory hormones regulating blood pressure. Second messenger-systems (cAMP, Ca++-cGMP) which mediate the effects of most non-steroidal hormones are also involved in the action of prostaglandins, at least of the E-and F-types. Disturbances in prostaglandin metabolism (increased or decreased biosynthesis) are discussed to play a role in the pathogenesis of inflammation, pain, fever, hypertension, bronchial asthma and gastric or duodenal ulcer formation. Drugs with antiinflammatory, analgesic and antipyretic activity have been shown to be potent inhibitors of prostaglandin formation. The correlation of a local prostaglandin deficit or the therapeutic use of single effects of prostaglandins by administration of exogenous compounds (natural prostaglandins or modified derivatives) has so long been less satisfactory because of their large number of biological actions which lead to undesired side effects. Extensive experience have been obtained in the successful induction of therapeutic abortion. This effect is based on the stimulatory action of E- and F-type prostaglandins on the smooth muscles of the pregnant uterus which is resistent to the influence of other stimuli, e. g. oxytocin. Here the incidence of side effects could be reduced by local administration of low doses of prostaglandins into the uterine cavity. A general improvement of the therapeutic usefulness of prostaglandins will however only be achieved, if modified derivatives with more specific actions on the desired "target" tissues are available.
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PMID:[Biology of prostaglandins with reference to therapeutic aspects]. 16

Sixty-six patients with chronic hypertension were cared for during a total of 72 pregnancies. Patients were treated at home primarily by greater than or equal to 4 hours of bed rest daily in the left recumbent position. Only patients whose diastolic blood pressures remained greater than 110 mmHg were treated with hydralazine (Apresoline, Ciba). With this plan of treatment there were only 3 perinatal deaths for an uncorrected perinatal mortality of 4.1% (1.4% corrected). Twenty-nine percent of the patients had babies that were small for gestational age, 13.8% had positive oxytocin challenge tests, and 36.8% developed superimposed preeclampsia. When compared with the outcome of previous pregnancies, the program of bed rest lowered perinatal mortality from 16.8 to 8.8%. Thus, it is suggested that bed rest together with the avoidance of diuretics and the judicious use of hydralazine results in the most favorable fetal outcome.
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PMID:Evaluation of a program of bed rest in the treatment of chronic hypertension in pregnancy. 42 5

Fifty-three pregnant women with moderately severe hypertension were randomly allocated to treatment with methyldopa or oxprenolol. There were no significant differences between the groups in age, height, weight, parity, or stage of gestation at the start of treatment. The outcome of pregnancy was better in the group treated with oxprenolol, with greater maternal plasma volume expansion and placental and fetal growth. No intrauterine deaths occurred in either group, and antepartum fetal distress, detected by oxytocin challenge testing, was evident in only one patient, who received methyldopa. This infant, and one other in the methyldopa group, died in the neonatal period. No neonatal deaths occurred in the oxprenolol-treated group. Even in this small number of patients these results were considerably better than those in untreated women with hypertension of similar severity. Apgar scores in both groups were equivalent at birth, while blood sugar concentrations were higher in the oxprenolol group. Oxprenolol appears to be safe and effective in controlling hypertension during pregnancy. There was no evidence of harmful effects on the fetus, and oxprenolol may offer a selective advantage over methyldopa for fetal growth and wellbeing in utero.
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PMID:Randomised comparison of methyldopa and oxprenolol for treatment of hypertension in pregnancy. 46 38

Intra-arterial injections of bradykinin into the hindlimb of the rabbit cause two types of cardiovascular reflex effects displayed in succession. The first-type effects appear early and are of inhibitory nature, being represented by systemic hypotension, contralateral hindlimb vasodilation and bradycardia; the second-type effects appear later and are excitatory in nature, consisting of hypertension, hindlimb vasoconstriction and tachycardia and occur closely associated with behavioral manifestations typical of the reaction to pain. Both the depressor and pressor effects are accompanied by hyperventilation. Analogous biphasic reflex responses may be caused by intraarterial injections of potassium ions. On the contrary, hypertonic solutions (NaCl, glucose) usually only produce second-type excitatory responses. No significant cardiocirculatory reflex effects are induced by even high doses of serotonin, nicotine, adenosine, adenosine triphosphate, adrenalin, noradrenalin, angiotensin, vasopressin and oxytocin. General anesthesia greatly inhibits the pressor reflexes and potentiates the depressor responses (to bradykinin and K ions) but does not appear to be a necessary condition for provoking depressor reflexes by chemical stimulation of somatic afferents. Both chemoreflex responses are prevented by sectioning the somatic nerves of the injected limb. Denervation of sinoaortic areas and of cardiopulmonary receptors by bilateral cervical vagotomy or complete removal of the skin from the injected limb does not prevent either type of chemoreflex response. These depressor and pressor chemoreflexes have been ascribed to activation of two functionally distinct types of sensory receptors in the skeletal muscle, differently sensitive to chemical substances and selectively concerned with different patterns of cardiocirculatory reflex response.
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PMID:Cardiovascular and respiratory chemoreflexes from the hindlimb sensory receptors evoked by intra-arterial injection of bradykinin and other chemical agents in the rabbit. 76 67

Because of the unresolved controversy regarding the effect of epidural anesthesia upon uterine contractility, it was decided to study its effect on a small number of patients. Intrauterine and intra-arterial continuous pressure, continuous fetal heart rate, and maternal heart rate recordings were obtained from at least 20 minutes before administration of the epidural anesthic until complete dilatation in these patients. Nineteen patients were in spontaneous labor, and 18 had labor stimulated with oxytocin. Plain lidocaine, 1 or 1.5%, was used in 12 patients (30 observations), and lidocaine with epinephrine, 1:200,000 was used in 26 patients (51 observations). Uterine contractions were calculated in Montevideo units for 60 minutes following the epidural anesthetic. The changes, if any, were compared in both groups. There was a significant decrease in uterine activity when epinephrine was added to the anesthetic solution, mainly a lessening of intensity. There were comparable decreases in systolic/diastolic blood pressure in both groups and compensatory tachycardia. In one case, severe hypertension was observed following administration of lidocaine epinephrine. It was concluded that the addition of epinephrine to the anesthetic solution predictably produces diminution of uterine activity, and it does not give "cardiovascular support" to the laboring patient.
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PMID:The effect of epidural anesthesia on uterine activity and blood pressure. 93 11

Blood loss and the incidence of emetic sequelae were assessed in 148 patients undergoing midcavity forceps delivery under continuous lumbar extradural analgesia. Five units of oxytocin i.v. was found to be as effective as ergometrine 0.5 mg i.v. in reducing blood loss at delivery. Nausea, retching or vomiting occurred in 35 (46%) of the mothers who received ergometrine and in none of those who received i.v. oxytocin. The cardiovascular side-effects of ergometrine and oxytocin are reviewed and compared with special reference to patients with hypertension and heart disease. It is suggested that 5 units of oxytocin i.v. should be preferred in these high-risk patients. Because of the absence of an emetic action, i.v. oxytocin is preferable to i.v. ergometrine for patients receiving extradural analgesia.
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PMID:Ergometrine, oxytocin and extradural analgesia. 95 92

An 18-year-old primipara developed acute hypertension leading to cerebral edema and convulsions following the IV injection of a bolus of 10 units of oxytocin with 0.2 mg methylergonovine maleate. Oxytocin in a dose of more than 2 units should not be administered IV in a single injection, as severe hypotension may result. If oxytocin is required, it can be injected either IM, or by IV pump or drip. The use of ergot in obstetrics should be limited to the treatment of life-threatening postpartum hemorrhage and be given only by the IM route. Ergot should not be administered to patients with cardiac, renal, or hypertensive disease, or in association with a vasoconstrictor.
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PMID:Postpartum hypertension and convulsion after oxytocic drugs. 103 98

Seven hundred sixty-seven oxytocin challenge tests (OCT) were performed on 333 high-risk maternity patients. All of the patients had pregnancies complicated by diabetes mellitus, suspected postmaturity, preeclampsia, intrauterine growth retardation, hypertension and other disorders. In conjunction with OCT, 24-hour urinary estriol determinations were performed. Negative OCT's were reassuring for fetal well-being. There were 26 positive OCT's on 24 patients. A positive test was significant in identifying endangered fetuses existing in a markedly unfavorable environment. In our experience, we found the OCT more reliable and more predictable than urinary estriol determination. The oxytocin challenge test proved to be significant in the successful management of these 333 high-risk patients.
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PMID:Oxytocin challenge test in high-risk pregnancy. 125 May 37

Pregnancy complications, drugs and surgical interventions during pregnancy, fetal growth, medications and interventions during labor, labor complications as well as fetal heart activity during labor in a group of 114 term infants without malformations, but with signs of central nervous system (CNS) damage throughout early neonatal period are compared with paired group of term healthy infants born in the same presentation and mode of delivery. Among prelabor factors only maternal hypertension (found in 16.7% of encephalopathy children versus 0.8% in a control group) was significantly correlated with CNS damage. Fetal growth retardation and long term ritodrine administration were found more frequent in encephalopathy than in healthy group of infants, although statistical significance between the groups could not be demonstrated. A prolonged second stage of labor, high oxytocin dosage, too frequent uterine contractions and vacuum extractions were found significantly correlated with neonatal encephalopathy. CTG pattern during labor was normal in only 28.9% of children, with encepalopathy prepathologic in 46.4% and pathologic in 24.7%. The respective percentages for healthy newborns were: 82.5%, 16.25% and 1.2%. All differences between the groups were statistically significant. Mean duration of prepathologic CTG score in the group of infants with encephalopathy (78.8 minutes) as well as of pathologic score (51.7 minutes) was significantly longer than in healthy infants (23.7 minutes prepathologic and 7 minutes pathologic).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Pregnancy and labor associated with encephalopathy in neonates during the early neonatal period]. 134 15


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