Biomedical subjects

A Norström

Publications and source records attributed to A Norström.

At least 73 records · Page 4Linked to original sources

PubMed1986

Hormonal effects on collagenolytic activity in the isolated human ovarian follicular wall.

Tissue pieces from the wall (i.e. tunica albuginea with adjacent theca externa) of human follicles were incubated with and without various hormones and their potential influence upon the collagenolytic activity was evaluated. Following incubation the collagenase activity was determined in the incubation medium by measurement of the hydrolytic activity against the synthetic peptide 2,4-dinitrophenyl-Pro-Gln-Gly-Ile-Ala-Gly-Gln-D-Arg-OH. Stimulated collagenolytic activity was seen in the presence of relaxin and oxytocin whereas prostaglandin E2, prostaglandin F2 alpha, progesterone and 17 beta-estradiol were without effect. It is concluded that the stimulated collagenolytic activity induced by relaxin and oxytocin may be of importance for the degradation of collagen which occurs prior to follicular rupture.

Adult↗

PubMed1986

Interaction between prostaglandin E2 and noradrenalin on collagen synthesis in human cervical tissue during pregnancy.

The effects of prostaglandin E2 (PGE2) and noradrenalin (NA) on the incorporation of [3H]proline in cervical tissue of pregnant women were investigated. NA inhibited the incorporation in early as well as in term pregnancy. PGE2 counteracted the NA-effect in the former group of patients but did not affect the influence of NA at term. The results demonstrate an interaction between PGE2 and NA and point to a hitherto unknown effect of NA in the regulation of cervical connective tissue metabolism.

Cervix Uteri↗

PubMed1986

Induction of labor by intra-cervical PGE2 in viscous gel. Mechanism of action and clinical treatment routines.

Induction of labor in women with immature cervix was accomplished by four different treatment schedules. The case material included a total of 100 subjects, each treatment group having 25 cases: Group A: Intravenous oxytocin; Group B: Intracervical PGE2-gel followed by intravenous oxytocin; Group C: Intracervical PGE2-gel twice with a 12-hour interval; Group D: Intracervical placebo gel twice with 12-hour interval. Oxytocin did not influence the Bishop score (B.S.) unless in the presence of active labor contractions. In contrast, there was an increment in B.S. by 3.6 points on average within 12 hours following PGE2-gel as calculated from data of subjects without signs of contractions. These results support the concept of a local action of PGE2-gel. The increment in B.S. was larger in subjects with very immature cervices (B.S. less than or equal to 2) than in those with moderately immature scores (B.S. 4). A second PGE2-gel instillation did not increase the B.S. above the level achieved by the first application, indicating that pharmacological ripening of the cervix by a single dose of PGE2 results in an effect approaching maximum. The success rate was the same for oxytocin and PGE2-gel treated women during the first 24 hours, when approximately 40% of the women had given birth. The oxytocin group remained at that level of success rate, whereas the PGE2-gel-oxytocin and PGE2-gel X 2 series continued to improve their success rate up to 75%. An interesting finding in the study was that women given PGE2-gel twice did not need intravenous oxytocin stimulation except in a few cases.

Adult↗

PubMed1986

A procedure for the analysis of S-benzyl-N-acetylcysteine and S-(o-methylbenzyl)-N-acetylcysteine in human urine.

Analytical methods for mercapturic acids, the end-products of glutathione metabolism of the industrial solvents toluene and o-xylene (i.e., S-benzyl-N-acetylcysteine and S-(o-methylbenzyl)-N-acetylcysteine), added to human urine have been developed. The sensitivity is 2 ng/microliter (R.S.D. = +/- 13%) and 1 ng/microliter (R.S.D. = +/- 6.4%) urine for S-benzyl-N-acetylcysteine and S-(o-methylbenzyl-N-acetylcysteine, respectively, when using the h.p.l.c. method. The corresponding sensitivities for the g.l.c.-mass spectrometric method are 0.5 and 0.3 ng/microliter urine, respectively.

Acetylcysteine↗

PubMed1986

Influence of prostaglandins and adrenoceptor agonists on contractile activity in the human cervix at term.

The influence of prostaglandins as well as adrenoceptor agonists and antagonists on contractile activity of isolated cervical smooth muscle from term pregnant women was studied. Prostaglandin E2 had an inhibitory effect at extremely low concentrations. Inhibition also was induced by prostaglandin F2 alpha, prostaglandin I2, and 6-keto-prostaglandin F1 alpha, but at considerably higher concentrations. Contractions evoked by noradrenaline or phenylephrine were blocked by the alpha-adrenoceptor antagonist phenoxybenzamine. The beta-adrenoceptor agonist terbutaline acted as an inhibitor, whereas isoprenaline in most cases stimulated contractile activity. The inhibitory action of prostaglandins and especially the high sensitivity to prostaglandin E2 point to a physiologic role of these compounds for cervical dilatation and retraction. A predominance of alpha-adrenoceptors might be of importance for the maintenance of cervical competence during pregnancy.

Adrenergic alpha-Agonists↗

PubMed1985

Effects of PGE2 and PGF2 alpha on the simulation by noradrenaline and oxytocin of human cervical muscle activity at term.

Cervical specimens were obtained by needle biopsy in connection with caesarean section at term pregnancy. The preparations were superfused in an organ chamber and contractions were registered isometrically. Prostaglandin (PG) E2 and F2 alpha inhibited spontaneous contractions. The stimulatory action of noradrenaline was not influenced by PGF2 alpha but was reduced by PGE2 whereas both PGs abolished the excitatory effect of oxytocin.

Cervix Uteri↗

PubMed1985

The influence of prostaglandin E2 and oxytocin on the incorporation of [3H]proline and [3H]glucosamine in the human amnion.

Fetal membranes were obtained in connection with 1st-trimester abortion and vaginal delivery or elective caesarean section at term. Pieces of the isolated amnion membrane were incubated in vitro with [3H]proline or [3H]glucosamine in the presence of prostaglandin (PG) E2 or oxytocin. PGE2 reduced the labelling with [3H]proline in the 1st trimester and in membranes obtained at vaginal delivery, whereas an increase of incorporation was observed before start of labour. Oxytocin reduced [3H]proline labelling at any stage. In membranes from vaginally delivered women both oxytocin and PGE2 stimulated the incorporation of [3H]glucosamine, whereas oxytocin diminished radiolabelling in the other experimental groups. Regarding the radiolabelling with [3H]proline and [3H]glucosamine as reflecting the de novo formation of collagen and proteoglycans, respectively, it is suggested that both PGE2 and oxytocin, by their influence on connective tissue metabolism, may regulate the tensile properties of the fetal membranes.

5,8,11,14-Eicosatetraynoic Acid↗

PubMed1985

Effects of 9-deoxo-16,16-dimethyl-9-methylene PGE2 on muscle contractile activity and collagen synthesis in the human cervix.

The in vitro effects of a stable PGE-analogue (9-deoxo-16,16-dimethyl-9-methylene PGE2 (9-methylene PGE2) on human cervical tissue was investigated. The influence of the analogue on collagen biosynthesis was studied by measuring the incorporation of 3H-proline, while smooth muscle effects were evaluated by isometric recording of contractile activity. The specimens were obtained by needle biopsy from women in early and late pregnancy and from nonpregnant women of fertile age. 9-methylene PGE2 compared with controls increased the incorporation of 3H-proline in the secretory phase and before the 9th week of pregnancy, whereas radiolabelling was decreased in the follicular phase, in the 9th-12th week and at term. With respect to incorporation of 3H-proline,9-methylene PGE2 was equipotent to PGE2. 9-methylene PGE2 inhibited spontaneous contractile activity in early as well as in late pregnancy but increased muscular activity in nonpregnant patients. The inhibitory effects of the analogue was similar to that of PGE2 but the natural compound was considerably more potent in this respect.

16,16-Dimethylprostaglandin E2↗

PubMed1985

Leukotrienes and myometrial activity of the term pregnant uterus.

Biopsies from different segments of the pregnant human uterus were superfused in organ chambers and contractile activity was registered. Leukotriene C4(LTC4) caused inhibition of spontaneous but not noradrenaline induced contractile activity in strips from the cervix. This effect occurred both in early pregnancy and at term. However, the lower and the upper uterine segment of the term pregnant uterus did not respond to LTC4. The results represent a documentation of the segmental differentiation in the uterine response to eicosanoids.

Cervix Uteri↗

PubMed1985

Relaxin-induced changes in adenosine 3',5'-monophosphate levels in the human cervix.

The effects of porcine relaxin on the levels of cAMP in human cervical tissue were studied in vitro. The specimens were obtained by needle biopsy from women undergoing hysterectomy, legal abortion in the first trimester or elective Caesarean section at term, and were incubated in Krebs-Ringer buffer for 15 min in the presence of porcine relaxin (5 micrograms/ml, 3000 GPU/mg). cAMP was determined using a modified protein binding assay. The concentration of cAMP was higher in pregnant than in non-pregnant women. Relaxin stimulated the production of cAMP in the 7th-8th week of gestation and at term but did not significantly alter the cervical cAMP levels in neither non-pregnant women nor in women in the 10th-12th week of pregnancy. Previous studies have shown that porcine relaxin reduces collagen synthesis in tissue from the human cervix and lower uterine segment. The present observations indicate that these effects can be mediated by cAMP.

Cervix Uteri↗

PubMed1985

The role of prostaglandins for the coordination of myometrial forces during labour.

Systematic studies using a superfusion technique for recording myometrial contractility in vitro have been conducted in our department to explore whether prostaglandins (PG) have a differential action on the different segments of the pregnant uterus and also whether the qualitative and quantitative response undergoes a change during spontaneous labour. Myometrial specimens were excised from the fundal area and from the lower uterine segment at elective caesarean section in the 39th week of pregnancy before commencement of labour and at acute caesarean section during ongoing labour. Before labour PGF2 alpha was without or had a very weak effect on upper segment preparations but was stimulatory on lower segment specimens. PGE2 and PGI2 generally induced a biphasic dose-dependent response (stimulation followed by inhibition). During spontaneous labour PGF2 alpha and PGE2 always stimulated upper segment preparations while the contractile activity of specimens from the lower segment was inhibited by PGE2, PGF2 alpha was generally without effect. PGI2 had the same biphasic action before as during labour. With all reservations for the validity of in vitro experiments, the results favour the hypothesis that initiation of labour in the human involves a qualitative shift in the myometrial reactivity to prostaglandins. These alterations may involve suppression of expulsive forces and perhaps some tightening of the lower uterine segment during pregnancy. Following initiation of labour there is a marked increase in the excitatory action of both PGE2 and PGF2 alpha in the fundal area while the lower uterine segment reacts in a way that favours dilatation.

Dinoprost↗

PubMed1985

Has cervical smooth muscle any physiological role in the human?

Strips of human cervical tissue were obtained by needle biopsy and contractile activity was registered isometrically in a tissue chamber perfused by Krebs-Ringer bicarbonate buffer. The most frequently encountered pattern of contractile activity was high frequency-short duration. Prostaglandin (PG)E2, PGI2 and 6-keto-PGF1 alpha had an inhibitory effect on the muscular activity. Cervical muscle from pregnant women was more sensitive to PGE2 than specimens from non-pregnant women. PGF2 alpha had no apparent effect on cervical contractility in non-pregnant and early pregnant patients. In late pregnancy, however, PGF2 alpha inhibited muscle contractions. The present results point to a physiological role of the cervical muscles for the control of cervical competence during pregnancy. The inhibitory effect of PGs on the muscle activity may promote cervical dilatation and retraction.

6-Ketoprostaglandin F1 alpha↗

PubMed1985

Oxytocin and cervical connective tissue.

The effect of oxytocin on collagen synthesis in the pregnant human cervix and lower uterine segment was studied in incubation experiments by measuring the incorporation of 3H-proline. Oxytocin had a concentration related inhibitory effect on the labelling with 3H-proline. Vasopressin in the corresponding concentrations had only a weak effect on the incorporation of 3H-proline. Addition of indomethacin did not influence the response to oxytocin indicating that the effect was probably not mediated by prostaglandins. These results suggest that oxytocin under in vitro experimental conditions influences cervical connective tissue metabolism which is in contrast to current clinical experience.

Cervix Uteri↗

PubMed1985

Irritative complaints, carboxyhemoglobin increase and minor ventilatory function changes due to exposure to chain-saw exhaust.

Complaints of irritation in the eyes, nose and throat as well as dyspnea during work prompted this study to determine whether chain-saw exhaust produces acute exposure effects in loggers. Interviews concerning respiratory symptoms and rating of complaints were conducted for 211 loggers at industrial health care centers. Measurements of carboxyhemoglobin, spirometry and exposure to hydrocarbons, carbon monoxide and aldehydes were assessed for 23 loggers over 36 work periods lasting 2 h each. The prevalence of chronic bronchitis among the 211 loggers was 6%. Irritative complaints of eyes, nose and throat were common and significantly higher than in a reference group. The exposure levels were all below established threshold limit levels, except for carbon monoxide. There was a significant correlation between carbon monoxide exposure and blood carboxyhemoglobin levels. A small but significant decrease of FEV1% and FEF 25-75% during the work periods indicated minimal broncho-constriction, possibly mediated through a reflex mechanism due to irritation of upper airways.

Adolescent↗

PubMed1984

Inhibitory action of relaxin on human cervical smooth muscle.

The influence of purified porcine relaxin on contractility of human cervical smooth muscle was investigated in vitro. Strips of cervical tissue were obtained by needle biopsy from pregnant and nonpregnant women and were mounted in a superfused organ chamber for isometric measurement of contractile activity. Relaxin (0.005-25 micrograms/ml) inhibited the spontaneous contractions in cervical strips from 18% of nonpregnant, 68% of early pregnant, and in 100% of term pregnant women. These results indicate that relaxin has an inhibitory action on cervical smooth muscle and that this effect is more constantly detected as pregnancy proceeds.

Animals↗

PubMed1984

Influence of progesterone, androstenedione and oestradiol-17 beta on the incorporation of [3H]proline in the human follicular wall.

The incorporation of proline, a precursor for collagen specific hydroxyproline, is regarded to reflect the metabolism of collagen. In vitro experiments were carried out to investigate the influence of sex steroids on the incorporation of [3H]proline into the human follicular wall. Tissue pieces from the apical wall of follicles at different stages of development were incubated in the presence of the steroids and [3H]proline, and the tissue bound radioactivity was determined. Progesterone induced a decrease of radiolabelling in both unripe and pre-ovulatory follicles. Androstenedione caused a similar effect but only in pre-ovulatory follicles. The influence of oestradiol-17 beta on the incorporation of [3H]proline was less pronounced with a tendency towards a decrease of radiolabelling in both types of follicles. It is suggested that the observed biochemical changes induced by sex steroids are of importance for connective tissue remodelling preceding human follicular rupture.

Adult↗

PubMed1984

Regulatory influence of relaxin on human cervical and uterine connective tissue.

Cervical tissue was obtained from women undergoing legal abortion in the 7th-15th week of gestation and tissue from the lower uterine segment was excised at elective Casearean section in the 38th-40th week. The specimens were incubated with [3H]proline in the presence of relaxin or prostaglandin E2 (PGE2). Relaxin had a concentration related inhibitory effect on the radiolabelling in the 7th-9th week but failed to influence the amino acid uptake in the 10th-15th week of pregnancy. PGE2 had the inverse effect, i.e. no influence in the former group but reduced incorporation of proline in the latter group of patients. Incubation of tissue from the lower uterine segment showed a similar response as that of the early pregnant cervix. It is concluded that relaxin has a significant influence on [3H]proline incorporation by cervical and uterine tissue under in vitro experimental conditions.

Amino Acids↗

PubMed1984

Effects of oxytocin on cervical and uterine connective tissue.

The effect of oxytocin on collagen metabolism in the cervix and lower uterine segment of pregnant women was studied by measuring the incorporation of [3H]proline in vitro. Oxytocin had a concentration related inhibitory effect on the labelling with [3H]proline. Addition of indomethacin did not influence the response to oxytocin indicating that the effect was not directly mediated by prostaglandins. Oestradiol-17 beta potentiated the effect of oxytocin. Vasopressin decreased the incorporation of [3H]proline slightly but the action of this hormone was significantly less than that of oxytocin. The results suggest that oxytocin under in vitro experimental conditions influences cervical connective tissue metabolism which is in contrast to current clinical experiences.

Arginine Vasopressin↗