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Biomedical subjects

A Norström

Publications and source records attributed to A Norström.

At least 91 records · Page 5Linked to original sources
PubMed1984

Acute effects of prostaglandins on the biosynthesis of connective tissue constituents in the non-pregnant human cervix uteri.

Biochemical effects of prostaglandins (PGs) on the connective tissue of the human cervix uteri were studied by measuring the net incorporation of [3H] glycine and [3H] glucosamine into cervical specimens, incubated in vitro in the presence of PGE2 and PGF2 alpha. The net radiolabelling with these isotopes, precursors of collagen and proteoglycans, was influenced by PGE2 and PGF2 alpha in a similar manner. In the follicular phase of the menstrual cycle, both PGs induced a decreased radiolabelling with glycine but caused an increased labelling with glucosamine. In the luteal phase, the situation was reversed, i.e. the incorporation of glycine was augmented and that of glucosamine was reduced in tissue incubated with PGs. It is suggested that PGs can modulate the fibroblast biosynthesis activity in such a way that either the synthesis of fibrous structures (collagen) or that of ground substance constituents (proteoglycans) is favored.

Cervix Uteri↗
PubMed1984

Adrenoceptor mechanisms in the regulation of contractile activity in the human cervix.

The effects of adrenoceptor agonists and antagonists on the contractile activity of cervical strips from early pregnant and nonpregnant women were studied. Noradrenaline and the alpha-adrenoceptor agonist, phenylephrine, had a stimulatory effect on smooth muscle activity. This response could be blocked totally by the alpha-adrenoceptor antagonist, phenoxybenzamine. Isoprenaline, known to be a beta-adrenoceptor agonist with some alpha-adrenoceptor activity, had stimulatory and inhibitory effects, whereas the beta 2-adrenoceptor agonist, terbutaline, exhibited a pure inhibitory action. The inhibitory effects of isoprenaline and terbutaline were totally blocked by the beta-adrenoceptor antagonist propranolol. In pregnant patients, the sensitivity to noradrenaline was significantly higher, and the inhibitory action of terbutaline was less pronounced, which indicated the predominance of alpha-receptor activity in the uterine cervix during pregnancy.

Adolescent↗
PubMed1984

Influence of prostaglandins on contractility of the isolated human cervical muscle.

The contractile activity of smooth muscle from the pregnant and nonpregnant human cervix uteri was studied in organ bath experiments. Several patterns of spontaneous activity with varying frequency and amplitude were observed. Prostaglandin E2 inhibited muscle activity in a concentration-dependent manner, and total inhibition was achieved in pregnant tissue at extremely low concentrations. Prostaglandin F2 alpha, on the other hand, did not influence spontaneous contractions. Prostaglandin I2 and 6-keto-prostaglandin F1 alpha had an inhibitory effect but only at comparatively high concentrations. 5,8,11,14-Eicosatetraynoic acid and indomethacin abolished spontaneous contractions, indicating a regulatory influence of endogenous prostanoids on cervical contractility. The extreme sensitivity to prostaglandin E2 and enhancement of its action during early pregnancy provide evidence for a specific role of this compound in controlling cervical smooth muscle activity in the human female.

6-Ketoprostaglandin F1 alpha↗
PubMed1983

Influence of prostaglandin E2 on proteoglycan synthesis in the human ovarian follicle wall.

The effect of prostaglandin (PG) E2 on the incorporation of 3H-glucosamine in the human follicular wall was investigated in vitro. Follicles were obtained from women undergoing sterilization via minilaparotomy. Tissue pieces of the follicular wall were incubated in the presence of PGE2 and 3H-glucosamine and the tissue-bound radioactivity was determined. PGE2 induced a significant increase of radiolabelling in the apex of the mature follicle wall but did not significantly affect the incorporation in other parts of the wall, nor in the wall of less developed follicles. The incorporation of glucosamine, a precursor of glucosaminoglycans, is regarded to reflect the synthesis of proteoglycans. The demonstrated increase in the incorporation of 3H-glucosamine in the apical wall of the mature follicle in response to PGE2 indicates that PG-mediated stimulation of proteoglycan synthesis is of importance for follicular rupture.

Dinoprostone↗
PubMed1983

Experimental studies on the influence of prostaglandins on the connective tissue of the human cervix uteri.

The influence of prostaglandins (PGs) on the synthesis of collagen and proteoglycans in the human cervix was estimated by incubation in vitro of cervical biopsy samples in the presence of tritiated amino acids and glucosamine after addition of PGE2, PGF2 alpha and 6-keto-PGF1 alpha. In the follicular phase of the menstrual cycle PGs increased the labelling with [3H] glucosamine but reduced the labelling with [3H] hydroxyproline, [3H] proline and [3H] glycine. Conditions were reversed in the luteal phase. The stable metabolite of PGI2, 6-keto-PGF1 alpha, had an effect similar to that of the classical PGs. In the early period of the first trimester the pattern of PG effects was the same as in the luteal phase, i.e. the labelling with [3H] proline was increased and the incorporation of [3H] glucosamine was reduced after treatment with PG. At the end of the first trimester, PG affected the radiolabelling in an inverse way. It is concluded that PGs are involved in the control of the biosynthetic activity of the cervical connective tissue. PGs may play a role of modulators, reinforcing or accelerating the current biosynthetic activity, and directed mainly by hormonal, neuronal and other factors.

6-Ketoprostaglandin F1 alpha↗
PubMed1983

Interaction between PGs and catecholamines on cervical collagen synthesis.

Specimens from the upper part of the cervix were excised and chopped into 1 mm thick slices. These were incubated in buffer containing [3H] proline fortified with PGE2 and/or NA and the incorporation into total protein was measured after various incubation periods. In certain experiments the slices were preincubated with reserpine to deplete the tissue stores of catecholamines. Both PGE2 and NA were able to influence the incorporation of [3H] proline in such a way that the stimulatory effect of PGE2 was counteracted by reserpine in the luteal phase of the cycle, while NA-stimulated incorporation of [3H] proline was inhibited by PGE2 in the late follicular phase. Both clinical and experimental studies have shown that PGs per se interfere with the biophysical and biochemical properties of the cervix. The present results indicate that there also exists an interaction between PGs and catecholamines.

Cervix Uteri↗
PubMed1983

PGI2 may play a role in the pathophysiology of dysmenorrhea.

Small longitudinally or helically cut strips from the ascending branch of the uterine artery were mounted in organ chambers for isometric recording of contractile activity. PGI2(3-300 ng/ml) caused a concentration-dependent relaxation of spontaneously active preparations, whereas no inhibitory effect could be observed on non-active strips. Furthermore, the compound counteracted the stimulatory effects of PGE2, PGF2 alpha, and NA, but not that of transmural nerve stimulation. The effect of PGI2 could be of interest in that the compound may balance the action of vasoconstricting agents. A disturbance of this balance may be a hitherto unrecognized contributing pathophysiological mechanism in the development of dysmenorrhea.

Arteries↗
PubMed1982

Influence of prostaglandin D2 on the biosynthesis of connective tissue constituents in the pregnant human cervix.

Uterine cervical tissue was obtained from pregnant women undergoing abortion or caesarean section. The tissue was incubated in Krebs-Ringer bicarbonate buffer containing prostaglandin (PG) E2 and radioactive precursors for collagen (3H proline) and proteoglycans (3H glucosamine). After incubation the tissue-bound radioactivity was determined and related to the tissue dry weight. The effect of PGE1 on the net tissue radiolabelling varied with the gestational age and with the cervical status at operation. In early 1st trimester PGE2 increased the labelling with 3H proline but decreased that with 3H glucosamine. From the 12th week of gestation until term pregnancy conditions were reversed, i.e. the incorporation of 3H proline was reduced and that of 3H glucosamine was augmented following treatment with PGE2. After start of labour and rupture of the membrane, however, PGE2 diminished the labelling with 3H proline as well as 3H glucosamine. It is suggested that PGE2 is a modulator of biochemical events which underlie cervical ripening.

Abortion, Therapeutic↗
PubMed1982

Collagen synthesis inhibition by PGE2 within the human follicular wall--one possible mechanism underlying ovulation.

Follicular wall specimens were taken from various parts of human preovulatory follicles as well as from less developed follicles. The tunica albuginea was isolated and incubated for 2 h in Krebs Ringer bicarbonate buffer containing 3H-proline in the presence or absence of PGE2 (0.1 microgram/ml). Following incubation the incorporated radioactivity was determined and related to the protein content of each strip. PGE2 had a specific effect on the incorporation of 3H-proline into protein in the follicular wall. In the apical part of the preovulatory follicle a significantly decreased incorporation was registered, indicating a reduced net synthesis of collagen. However, PGE2 was without effect on specimens derived from the non-apical parts of the preovulatory follicles as well as from the less developed follicles. It is suggested that the registered biochemical changes induced by PGE2 are of importance for the process of human ovulation.

Adult↗
PubMed1981

A new prostaglandin E2-gel for pretreatment of the cervix in nulliparous patients having a late first trimester termination of pregnancy.

A new PGE2-gel, based on a cross-linked starch powder, has been developed. This gel seems to have solved several of the pharmaceutical and practical problems connected with local administration of prostaglandins. In a three-center study 120 nulliparous patients were given 0.5 mg PGE2 in 2.2 ml gel intracervically prior to dilatation of the cervix and evacuation of the uterus in late first trimester. Considerable cervical dilatation was obtained within 15 h. The frequency of side effects, including pain and gastro-intestinal discomfort was low. The technique can be recommended for outpatients.

Abortion, Induced↗
PubMed1981

The regulatory influence of prostaglandins on protein synthesis in the human non pregnant cervix.

Cervical connective tissue was obtained from non pregnant fertile women undergoing hysterectomy. Tissue specimens were mechanically chopped into 1 mm thick slices which were preincubated in Krebs-Ringer bicarbonate buffer containing PGE2 or PGF2 alpha (300 ng/ml). After 60 min the slices were transferred into fresh buffer with the corresponding PG-concentration and 3H-labelled proline or hydroxyproline. Following incubation (60 min) the protein bound radioactivity was determined and related either to the dry weight or to the protein content of each slice. The two methods used did not show any qualitative differences. The experiments showed that PG:s had a marked effect on protein synthesis in the cervical tissue. During the follicular phase incubation with both types of PG:s was followed by a decreased incorporation indicating decreased net synthesis of collagen while there was an increased incorporation and hence increased synthesis in the luteal phase. There was no significant influence on the distribution of the model amino acid 14C-AIB in the presence of PG:s neither in the follicular nor in the luteal phase. The present data point to an acute effect of PGE2 and PGF2 alpha on cervical collagen metabolism and indicate furthermore that the process is steroid hormone dependent. It is concluded that these substances may exert their effect by modulating the incorporation of amino acids into protein.

Amino Acids↗
PubMed1981

Influence of 6-keto-PGF1 alpha on collagen synthesis in the human cervix during various phases of the menstrual cycle.

Uterine cervix tissue, obtained from nonpregnant fertile women undergoing hysterectomy, was mechanically chopped into 1 mm thick slices and incubated in Krebs-Ringer bicarbonate buffer containing 6-keto-PGF1 alpha (0.03-10 microgram/ml) and 3H-proline. After incubation of 30-120 min the incorporated radioactivity was determined and related to the protein content of each slice. 6-keto-PGF1 alpha had specific and significant effects on the incorporation of 3H-proline into cervical tissue. In the follicular phase of the cycle a decreased incorporation was registered, indicating a reduced net synthesis of protein. However, increased radiolabelling was observed in the luteal phase, reflecting an augmented protein synthesis. It is suggested that 6-keto-PGF1 alpha, the stable metabolite of prostacyclin (PGI2), has the ability to influence cervical protein metabolism and that this effect is steroid hormone dependent.

6-Ketoprostaglandin F1 alpha↗
PubMed1980

Negative ion mass spectra of some polychlorinated 2-phenoxyphenols.

Polychlorinated 2-phenoxyphenols were studied by negative ion mass spectrometry. Common to almost all of the methane enhanced negative ion mass spectra were (M-1)-, (M-36-)-., (M-37)-, (M-72)-., and chorinated quinoxide ions. The (M-36)-. ion does not apparently form in a mechanism analogous to the thermal or photochemical ring closure of these compounds to form the chlorinated dioxins. The chlorinated quinoxide ion reflects the number of chlorines on the ring with hydroxy substituent. Collision-induced dissociation mass-analyzed ion kinetic energy spectra (CID-MIKES) from different isomers were qualitatively different in both the normal and charge reversed mode of operation. Comparison of these spectra with those from other classes of polychlorinated aromatic hydrocarbons such as the dioxins or the furans may reveal a common negative ion gas phase chemistry.

Anions↗
PubMed1979

Methane-oxygen enhanced negative ion mass spectra of polychlorinated diphenyl ethers.

Methane-oxygen enhanced negative ion mass spectra of 15 chlorinated diphenyl ethers contained some combination of [M-]-., [M-1]-, [M-19]-, [M-36]-, [M-55]-, and [M+35]- anions. The relative abundances of these ions are related to the chlorine substitution pattern. Similar ions appear in the negative ion spectra of polychlorinated anisoles. The study of known isomers of polychlorinated model compounds extends the utility of the negative ion method in the analysis of polychlorinated aromatics such as polychlorinated biphenyls, dioxins and furans. The spectra were shown to be very dependent on the temperature of the ion source; a temperature change of 25 degrees C was shown to have pronounced effects. Spectral variation with temperature has implications for computer library searches, ultimate sensitivity limits and analysis in the presence of interfering isobaric ions.

Chlorobenzenes↗