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Biomedical subjects

A Forman

Publications and source records attributed to A Forman.

At least 109 records · Page 6Linked to original sources
PubMed1985

Concentrations and contractile effects of substance P in the human ampullary-isthmic junction.

From 20 women undergoing hysterectomy, strip preparations were isolated from the outer, longitudinal and the inner, circular smooth muscle layer of the ampullary-isthmic junction (AIJ), together with small arterial segments dissected as ring preparations from the root of the mesosalpinx. The specimens were mounted in organ baths and isometric tension was recorded. In addition, tissue concentrations of substance P (SP) in the ampulla, AIJ and utero-tubal junction were determined by radioimmunoassay. Tissue concentrations of SP expressed as pmol X g tissue-1 (wet weight, +/- SE) amounted to 3.09 +/- 1.40 in the utero-tubal junction, 1.08 +/- 0.299 in the AIJ and 0.742 +/- 0.299 in the ampulla. In strips of circular muscle, SP at concentrations of 10(-7) -3 X 10(-6) mol X l-1 elicited a combined phasic and tonic response and in longitudinal muscle a mainly tonic contraction was produced. In both tissues, contractions elicited by SP were rapidly abolished in calcium-free medium. Nifedipine abolished the phasic contraction elicited in circular muscle by SP while the tonic response was resistant. The contraction in longitudinal muscle was reduced by 20-30%. Vasoactive intestinal polypeptide (VIP) decreased tension in preparations contracted by SP, prostaglandin F2 alpha and K+-depolarization (124 mmol X l(-1). In unstimulated oviductal arterial preparations, SP had no effect, while the peptide induced a transient relaxation of noradrenaline contracted preparations, and slightly decreased tension of K+-depolarized vessels. The results suggest that SP may be involved in the control of motility of the human AIJ.

Adult↗
PubMed1985

Differences in contractile activation between human myometrium and intramyometrial arteries.

Small intramyometrial arteries and pieces of adjacent myometrial tissue were obtained from 25 non-pregnant women undergoing hysterectomy. Vascular and myometrial preparations were dissected, mounted in organ baths and isometric tension was recorded. Myometrial strips, but no vascular preparation, developed spontaneous contractile activity. Noradrenaline (NA) and vasopressin (VP) contracted both vessels and myometrium. Prostaglandin F2 alpha (PGF 2 alpha) contracted the myometrial tissue, but had only a minor effect on the vessels. Removal of extracellular calcium almost abolished the myometrial responses to high K+ (124 mM)-solution, PGF 2 alpha, NA and VP. The vascular responses remaining after this treatment were 18% (K+), 34% (NA) and 25% (VP) of control contractions induced by high K+ (124 mM). Nifedipine potently depressed myometrial contractions induced by NA and VP, but was less active against the vascular responses to these agents. In preparations exposed to calcium-free medium, nifedipine (10(-7) M) almost abolished myometrial contractions induced by calcium in the presence of K+ (124 mM), NA or VP. It also effectively depressed vascular responses to calcium in the presence of K+, but was less active if NA and VP were present. It is suggested that PGF2 alpha has almost no contractant effect on intramyometrial arteries, and that the activation process in these vessels is much less dependent on extracellular calcium than that of the myometrium.

Adult↗
PubMed1984

Effects of nifedipine on human placental arteries.

Small chorionic plate arteries (outer diameter 600-700 micron) and umbilical arteries were obtained from human placentas following normal vaginal delivery. Tubal vascular preparations were dissected, mounted in organ baths, and isometric tension was recorded. None of the preparations developed spontaneous contractile activity. The course of potassium-induced contractions differed between chorionic and umbilical arteries. The chorionic arteries showed decreased response to 5-hydroxytryptamine (5-HT) as compared to the umbilical arteries, whereas the contractile response to prostaglandin F2 alpha (PGF2 alpha) was equal. In the chorionic arteries, nifedipine effectively inhibited potassium-induced contractions and, at concentrations of 10(-8)-10(-6) M, decreased responses to 5-HT and PGF2 alpha. Removal of extracellular calcium almost abolished the response to high potassium and reduced the response to both PGF2 alpha and 5-HT by 65%. Nifedipine (10(-8) M) significantly reduced, and nifedipine (10(-7) M) almost abolished, the contractile response induced by calcium after K+ (124 mM) depolarization, and in the presence of PGF2 alpha and 5-HT, nifedipine (10(-8)-10(-7) M) effectively depressed the responses to calcium. The results show decreased response to 5-HT with decreasing dimensions of the placental vessels, and suggest that small placental vessels utilize multiple sources of calcium for contractile responses. Nifedipine seems to interfere with some of these mechanisms and clinical use of the drug may imply a decreased fetal placental vascular resistance.

Arteries↗
PubMed1983

Intravaginal versus intracervical application of prostaglandin E2 in viscous gel for cervical priming and induction of labor at term in patients with an unfavorable cervical state.

Sixty term pregnant women with unripe cervix were randomly given either 0.5 mg of prostaglandin E2 (PGE2) in 2 ml of gel intracervically or 4 mg of PGE2 in 3 ml of gel intravaginally to prime the cervix and/or to induce labor. In patients with a highly unfavorable cervix (cervical score less than or equal to 3), the intracervical application was significantly more effective than the intravaginal. In patients with a more favorable cervical state (cervical score 4 or 5), the two routes of application were equipotent. Gastrointestinal side effects were registered after intravaginal but not after intracervical application. Myometrial activity was significantly more increased after intravaginal than after intracervical gel application. All children were born in good condition with an Apgar score greater than 7 within 5 minutes.

Adult↗
PubMed1983

Comparison of the effects of nicardipine and nifedipine on isolated human myometrium.

The effects of nicardipine, a calcium-entry blocker which also has a potent phosphodiesterase inhibitory action, were investigated on isolated human term-pregnant and nonpregnant myometrium, and compared with those of nifedipine. Both drugs relaxed pregnant and nonpregnant myometrial preparations contracted by potassium (127 mM), and also reduced or abolished contractions occurring spontaneously, or induced by prostaglandin F2 alpha, oxytocin and vasopressin. However, the effect of nicardipine had a slower onset of action than that of nifedipine, and the drug was significantly more potent than nifedipine is at least as effective as nifedipine. If the differences between the drugs can be reproduced also in vivo, nicardipine offers an interesting alternative to nifedipine for inhibition of undesired uterine activity.

Adult↗
PubMed1983

Effects of calcium and nifedipine on noradrenaline- and PGF-2 alpha-induced activity of the ampullary-isthmic junction of the human oviduct in vitro.

From 22 women undergoing hysterectomy at various stages of the menstrual cycle, strip preparations were dissected from the outer, longitudinal and the inner, circular smooth muscle layers of the ampullary-isthmic junction (AIJ). The strips were mounted in organ baths, and isometric tension was recorded. Spontaneous contractions were recorded mainly in circular muscle strips. Contractions were elicited by 127 mM-K+, 10(-6) M-noradrenaline and 10(-6) M-PGF-2 alpha. Potassium induced biphasic responses that were slightly different in the two tissues. In circular muscle strips, noradrenaline and PGF-2 alpha induced phasic contractions superimposed on a rise in tone. In longitudinal muscle specimens, the two compounds produced tonic responses. All types of mechanical activity were inhibited by removal of extracellular calcium. K+-induced responses and phasic contractions produced by noradrenaline and PGF-2 alpha could be abolished by 10(-6) M-nifedipine whereas the tonic contractions in the circular and longitudinal muscle were more resistant to the calcium antagonist. The results suggest that K+-induced responses in circular and longitudinal muscle of the human AIJ, and the phasic contractions in circular muscle, depend on calcium influx via potential-sensitive membrane channels. Receptor-operated calcium channels seem to be involved in the tonic contractions observed mainly in the longitudinal smooth muscle.

Adult↗
PubMed1983

Aspects of inhibition of myometrial hyperactivity in primary dysmenorrhea.

Uterine hypercontractility is considered to be an important factor in primary dysmenorrhea. A survey is given on possible mechanisms controlling the cytoplasmic concentration of free calcium and thereby contractile activity in the myometrial smooth muscle cell. Probably acting by different modes of action, inhibitors of prostaglandin synthesis, calcium antagonists and beta 2 stimulators have all been shown to reduce myometrial activity and relieve dysmenorrheic pain. The possibility of achieving further uterine relaxation after initial treatment with prostaglandin inhibitors by adding a calcium antagonist such as nifedipine is discussed. It is also suggested that when utilizing a reliable pressure recording technique in the evaluation of dysmenorrheic patients, the pronounced myometrial relaxation obtained by such combined therapy may be of diagnostic value.

Adrenergic beta-Agonists↗
PubMed1983

Low dose i.v. infusion of prostaglandin F2 alpha for induction of labor at term.

In 100 pregnant women at term, labor was induced for medical reasons by i.v. infusion of a low dose of prostaglandin F2 alpha (PGF2 alpha). With a dose not exceeding 6 micrograms PGF2 alpha/min, all patients were induced into labor. The mean induction-delivery time was 6.6 hours and the overall proportion of instrumental deliveries was 19%, including 6% cesarean sections. Very few side effects were observed. It is concluded that i.v. infusion of prostaglandin F2 alpha in a low dose regimen might be considered as an alternative to existing methods for the induction of labor at term.

Adolescent↗
PubMed1982

Effects of nifedipine on oxytocin- and prostaglandin F2 alpha -induced activity in the postpartum uterus.

In order to get additional information on spontaneous and drug-induced uterine activity in the early postpartum period, intrauterine pressure was registered by the microtransducer technique in 19 patients. The effects of the calcium entry blocker nifedipine were also tested. Myometrial activity was induced by infusion of oxytocin (10 patients) or prostaglandin F 2 alpha (nine patients). Both hormones increased myometrial activity, with slightly different patterns of contractility. Nifedipine effectively reduced contractions induced by both drugs. The microtransducer technique seems to be a convenient and safe method for studying the effects of drugs and hormones on uterine activity post partum. Furthermore, nifedipine administered orally is a potent inhibitor of drug-induced myometrial activity in the early postpartum period.

Adult↗
PubMed1982

Effects of nifedipine on spontaneous and methylergometrine-induced activity post partum.

Intrauterine pressure changes were recorded by microtransducer catheter in 17 women immediately post partum. In all patients, spontaneous contractile activity was recorded, characterized by high contraction amplitudes (110 to 350 mm Hg). The calcium entry blocker nifedipine effectively inhibited these contractions. Both in vitro, in strips of pregnant myometrium, and in vivo, methylergometrine induced a contractile activity that could be blocked by nifedipine. The conclusion is that, for the testing of drugs that affect the contractile activity of pregnant myometrium, the use of intrauterine pressure recording by microtransducer catheters in the early postpartum period provides a suitable model.

Adult↗
PubMed1982

Evidence for a local effect of intracervical prostaglandin E2-gel.

Eight primigravid women with a mean gestational age of 9.4 weeks (9 to 10 weeks) who were admitted for first-trimester abortion by dilatation and evacuation were preoperatively treated for 6 hours with either intravenous infusion of oxytocin or a strictly intracervical application of prostaglandin E2 (PGE2) in viscous gel. Myometrial activity was monitored by intrauterine pressure recording throughout the treatment. Contractile activity was more pronounced in the oxytocin-treated group, whereas cervical priming occurred after the PGE2 treatment only. Intracervical PGE2-gel is suggested to have direct effects on the cervical tissues, independent of uterine contractile activity. Furthermore, myometrial stimulation induced by escape of gel into the extra-amniotic space can be avoided by adjusting the volume of gel and technique of application to the dimensions of the cervix.

Abortion, Induced↗
PubMed1982

Combined effects of diflunisal and nifedipine on uterine contractility in dysmenorrhoeic patients.

In eight nulliparous women with severe primary dysmenorrhoea, intrauterine pressure was recorded on the first day of menstruation before and after administration of diflunisal 1000 mg. Uterine activity was significantly decreased in all patients but abolished in none. Seven women experienced almost complete relief of pain. To four of the patients, including the one who did not become pain-free after diflunisal, nifedipine 30 mg was also given. Uterine activity was abolished in all, but the patient not responding to diflunisal had persistent pains. It is suggested that diflunisal may be used for treatment of pain in primary dysmenorrhoea. Addition of nifedipine can produce a further decrease in uterine activity, but whether combined therapy may offer therapeutic advantages remains to be established.

Adolescent↗
PubMed1982

Effects of intracervical PGE2-gel on myometrial activity and cervical state in first trimester pregnancy.

In 7 primigravidae admitted for first trimester abortion by dilatation and evacuation, 0.5 mg PGE2 in viscous gel (5 patients) or placebo gel (2 patients) was applied intracervically 6 hours prior to the operation. Throughout the treatment period intrauterine pressure was recorded. Application of placebo gel induced no cervical ripening or myometrial activation. In all patients receiving active gel, a marked improvement of the cervical state was induced by the treatment. In three cases, this priming occurred in parallel to minimal changes in myometrial activity, without regular uterine contractions. In two patients, marked uterine activation was registered due to partly extraamniotic application. It is suggested, that the PGE2-gel has a direct effect on the cervical tissues. Further, the risk of partially applying the gel in the extraamniotic space, thus stimulating the myometrium, depends on the gel volume relative to the dimensions of the cervical canal and the application technique.

Abortion, Therapeutic↗
PubMed1981

The effect of danazol on the human female urethra.

The urethral pressure profile was recorded, at rest and under stress, from six women in fertile age, before and at the end of an eight-week treatment during which the probands received daily doses of 600 mg of Danazol. Only moderate decrease in maximum urethral pressure was established, at rest, though oestrogen production was markedly reduced. Reduction in transmission of intra-abdominal pressure to the urethra was registered under stress, but urethral closure pressure remained positive in all subjects. Bladder pressure and functional length of the urethra were almost unaffected. Danazol treatment does not seem to jeopardize maintenance of urinary continence in young females.

Adult↗