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Biomedical subjects

M Akerlund

Publications and source records attributed to M Akerlund.

At least 91 records · Page 5Linked to original sources

Uterine effects of N-alpha-triglycyl-(8-lysine)-vasopressin and 8-lysine-vasopressin in the first trimester of pregnancy.

Myometrial effects of a vasopressin hormonogen (N-alpha-triglycyl-(8-lysine)-vasopressin, TGLVP) and of 8-lysine-vasopressin (LVP) were studied in early pregnancy. Intrauterine pressure was recorded in 28 women, who were to have a therapeutic abortion at 8-12 weeks of gestation, and intravenous injection of TGLVP (0.5 and 1 mg) or LVP (0.1, 0.2 and 0.4 IU) were given, or control recordings without drug injection were obtained. TGLVP generally caused a biphasic increase in uterine activity with a rise in uterine tone as the most conspicuous initial effect followed by an increase in amplitude and duration of contractions. In the higher dose group the uterine activity remained significantly higher than in the controls during the rest of the recording period of 4-7 h. The magnitude of effect with the two doses of TGLVP did not differ significantly. The initial myometrial response to LVP resembled that to TGLVP but the effects disappeared within 10-45 min. In the controls the uterine activity did not change. It is suggested that vasopressin analogues could have a therapeutic value in the induction of abortion, but further basic studies are required to define this.

Adult↗

Interaction of vasopressin and prostaglandin on myometrial activity in vivo in the first trimester of human pregnancy.

The interaction of vasopressin (VP) and prostaglandin (PG) F2 alpha on myometrial activity was studied by intrauterine pressure recording in 40 women due to undergo therapeutic abortion in the first trimester. In a control group the uterine activity did not change during eight hours of recording without drug administration. In a second group, who had intravenous injections of 8-lysine vasopressin (LVP, 0.1-0.5 IU), it was found that 0.3 IU was the smallest dose that consistently gave an effect on myometrial activity, and that repeated injections gave responses of practically the same magnitude. In the remaining women in the study, LVP injections, 0.3 IU, were given before, during and two hours after an intravenous infusion of PGF2 alpha at 4 or 20 micrograms/minute. Although there were great individual variations, potentiation and enhancement of the LVP effect were the most common reactions, especially with the lower dose of PG. An interaction of PG and other endogenous myometrial stimulants such as VP might be important in the aetiology of spontaneous abortion and the combination of PG with VP-like substances might be of value in therapeutic abortion during the first trimester.

Adult↗

Progesterone effects on the evolution of myometrial activity in vivo in the non-pregnant rabbit.

In order to study the influence of progesterone on the myometrial activity ovarian secretion of progesterone was stimulated by intravenous injection of human chorion gonadotrophin (HCG, 75 IU) in 9 nonpregnant rabbits. 4 rabbits, used as controls, were given only saline. Plasma progesterone concentration in blood samples taken at frequent intervals (2-4 h) during the recording was measured by radioimmunoassay. In the controls, the myometrial activity and the plasma levels of progesterone did not change. After 1 h of HCG administration the amplitude of contraction began to decrease and the frequency began to increase after 3 h. After about 5 h the changes in amplitude and frequency were generally fully developed. This pattern of myometrial activity persisted throughout the recording period (12 h) and was also present in recordings made after 24 and 48 h of HCG injection. A maximal increase in plasma progesterone concentration (5.0 ng/ml) had already occurred by 2 h after the HCG injection and gradually decreased thereafter. It is concluded that an elevation in the level of progesterone in non-pregnant rabbits resulting from increased ovarian output (through HCG) has a pronounced and immediate depressing effect on the character of myometrial activity which is indicative of a shift from nonpregnant to pregnant type.

Animals↗

Prostaglandin-induced luteolysis in pregnant and pseudopregnant rabbits and the resultant effects on the myometrial activity.

The effect of prostaglandin (PG)-induced luteolysis on the myometrial activity in 20--21-day-pregnant and 11--12-day-pseudopregnant rabbits was studied by intrauterine pressure (IUP) recording during PG infusions. The same dose of PG (10 micrograms/h during 8h) was also given to 7 non-pregnant (untreated) does that were used as controls. Peripheral plasma concentration of progesterone and oestradiol-17 beta were measured at 2-h intervals during the infusion. Plasma progesterone level decreased significantly within 2 h or the start of infusion in pregnant and pseudopregnant does and continued to decrease; at the end of 8 h, the concentrations were 31 and 41%, respectively, of the pre-infusion levels. The amplitude of uterine contractions increased significantly after 4 h in pseudopregnant does, increased slightly but insignificantly in the pregnant does and showed no significant change in the non-pregnant does during PG infusion. The amplitudes developed in the pregnant and pseudopregnant does were significantly different. The direct effect of progesterone (1--3 micrograms/h during 4 h) was also studied in 7 non-pregnant rabbits. After 2 h the amplitude of contractions had decreased markedly and the pattern of activity had become irregular. The results support the concept of a myometrial inhibitory factor other than progesterone in rabbit pregnancy and suggest that this factor(s) originates in conceptus.

Animals↗

Pathophysiology of dysmenorrhea.

Mechanisms of possible pathophysiological importance in primary dysmenorrhea are discussed. Hyperactivity of the myometrium with accompanying uterine ischemia is considered to be of central importance in the causation of pain. Prostaglandins seem to be involved to a large extent in the development of the myometrial hyperactivity. Other mechanisms of possible importance such as ovarian hormones, cervical factors, vasopressin, nerves, and psychological factors can well act ultimately through prostaglandin release but an action directly on the myometrium and blood flow may also occur.

Adrenergic Fibers↗

Myometrial response to a long-acting vasopressin analogue in early pregnancy.

Intrauterine pressure was recorded for 4 to 6 hours in 21 healthy women having a therapeutic abortion at 6 to 9 weeks gestation. Fourteen of the women received an intravenous injection of 300 microgram of N-alpha-triglycyl-(8-lysine)-vasopressin (TGLVP) and seven were used as controls. Uterine tone and the amplitude and duration of uterine contractions increased in all women receiving the drug, uterine tone usually rising first, with a change in contractions as a secondary effect which lasted for the rest of the observation period. Uterine activity did not change in the controls. These results suggest that TGLVP might be used for the induction of abortion during the first trimester of pregnancy.

Abortion, Therapeutic↗

Recording of myometrial activity in the non-pregnant human uterus by a micro-transducer catheter.

A micro-transducer catheter was tested in vitro and in vivo for recording of myometrial activity in the non-pregnant human uterus and was also compared with conventional fluid-filled, open end catheters previously used for recording intra-uterine pressures. The micro-transducer catheter had a frequency response far above that of fluid-filled, open end catheters. It was easily introduced through the uterine cervix and was never obstructed. Provided that the sensory surface of the micro-transducer was kept from direct contact with the uterine wall by some special arrangement it gave recordings of the intra-uterine pressure, that were practically identical with those obtained by an open end catheter.

Catheterization↗

Myometrial activity and endometrial blood flow in an ectopic pregnancy.

Myometrial activity and endometrial blood flow were recorded in a patient with uterine haemorrhage and lower abdominal pain, who turned out to have a tubal pregnancy. The uterine contractions had an amplitude sometimes exceeding 400 mmHg and a duration up to 3.5 min. Thus, strong uterine contractions can appear during pregnancy without the presence of a gestational sac within the uterus. This is contrary to the assumption that processes in the foetal membranes initiate the sequence of events leading to abortion or labour.

Abdomen↗

Differences in the effects of vasopressin and oxytocin on rabbit myometrial activity and a possible mediation of prostaglandins.

Uterine responses to vasopressin and oxytocin were monitored in non-pregnant and 3- or 6-8-day-pregnant rabbits by recording the intrauterine pressure. Oxytocin stimulated uterine activity in all groups, but the effect of vasopressin was stimulatory in non-pregnant animals, inhibitory in those 3 days post coitum and weakly stimulatory in those later in pregnancy. Inhibition of prostaglandin (PG) synthesis, by the administration of indomethacin, reduced the spontaneous uterine activity as well as the responses to oxytocin and vasopressin in the non-pregnant rabbits, but had little effect in the pregnant animals. During infusion of PGF-2alpha, PGE-1 or PGE-2 in 6-8-day-pregnant rabbits, the stimulatory response to vasopressin, although slight before the infusion, was inhibited whereas the stimulatory response to oxytocin remained virtually unchanged. The results suggest that vasopressin and oxytocin under certain hormonal conditions, are able to activated the uterine contractions by mechanisms in which the involvement of PG is not obligatory.

Animals↗

Uterine activity in diabetes insipidus.

In two nonpregnant women with cranial diabetes insipidus, myometrial activity under different hormonal conditions was studied by intrauterine pressure recording. Recordings were performed when the women were under the influence of their regular treatment with desaminocys1-D-arg8-vasopressin (DDAVP), and when they had fully developed symptoms of their disease. Uterine activity was similar to that found in normal women under the same hormonal conditions, and generally did not change when symptoms of lack of vasopressin appeared. Both DDAVP (15-20 microgram), given intranasally, and lysin vasopressin (0.2 IU), given intravenously, stimulated uterine activity, particularly in late secretory menstrual phase. It is suggested that endogenous vasopressin is of minor importance for the induction of spontaneous uterine activity in nonpregnant women.

Adult↗

Effects of terbutaline on myometrial activity, uterine blood flow, and lower abdominal pain in women with primary dysmenorrhoea.

The effects of the selective beta2-receptor stimulator terbutaline (0-25 to 0-5 mg given intravenously) on myometrial activity, local uterine blood flow, and lower abdominal pain were examined during the first day of menstruation in 11 women with severe primary dysmenorrhoea. All had maximum intrauterine pressures between 200 and 350 mm Hg. During uterine contractions of high amplitude or long duration, the local endometrial blood flow decreased markedly, and the patients experienced the most intense pain. Terbutaline inhibited the myometrial activity, increased the blood flow, and relieved the pain.

Adult↗

Relationships between the concentrations of doxycycline in serum and in thoracic duct lymph after oral and intravenous administration in man.

The concentrations of doxycycline in serum and in thoracic duct lymph at various times after oral and intravenous administration of 200 mg of the drug were determined in 10 patients subjected to thoracic duct cannulation for diagnostic purposes. After oral administration, a mean peak serum concentration of 2.4 mug/ml (n=7) was obtained within 3 h; then the levels successively declined. The concentrations in thoracic lymph were lower, a mean peak concentration of 1.6 mug/ml being found 3 and 6 h after the intake. After intravenous administration (n=3), the concentrations of doxycycline in thoracic duct lymph were lower than but closely followed those in serum. The difference in concentrations between serum and lymph 1-6 h after the start of the infusion never exceeded 30%. The results suggest that doxycycline is rapidly distributed to the extracellular tissue fluids.

Administration, Oral↗

Effects of terbutaline on human myometrial activity and endometrial blood flow.

The selective beta2-receptor stimulator, terbutaline (0.25-0.5 mg), was given intravenously to healthy women at different times in the menstrual cycle. Intrauterine pressure was recorded by means of a microtransducer catheter, and local endometrial blood flow followed by a thermistor technic based on measuring thermodilution. The general response to terbutaline was a decrease in uterine activity and an increase in blood flow. However, the effects varied with the menstrual phase, being maximum around the onset of menstruation and minimum at midcycle. Pretreatment with propranolol (1 mg IV) completely inhibited the effects of terbutaline.

Adolescent↗