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J Rydnert

Publications and source records attributed to J Rydnert.

15 recordsLinked to original sources
PubMed1990

No abortion-inducing effect of the ulcer-healing dose of the synthetic prostaglandin E2 analogue enprostil in first trimester.

Milligram-range doses of E2 prostaglandins have long been used to induce labor or abortion in the second and third trimesters of pregnancy. Enprostil, a synthetic dehydroprostaglandin E2 structural analogue, is administered in microgram doses for the treatment of acute duodenal ulcer and acute gastric ulcer. This study examined the effect of the ulcer-healing dose and twice the ulcer-healing dose upon women in the first trimester of pregnancy. Two hundred and seven women who had requested legal abortion in the first trimester participated in two randomized, double-blind, placebo-controlled, parallel studies. They received two doses of enprostil 35 micrograms (the recommended dose for the treatment of duodenal and gastric ulcer) (n = 51), 70 micrograms (twice the recommended dose) (n = 53), or placebo (n = 103) 12 h apart. No drug-induced abortions occurred in any of the first-trimester pregnancies. Vaginal bleeding occurred in 4% of volunteers receiving the lower dose and 4% receiving the higher dose of enprostil. Vaginal bleeding occurred in up to 2% of volunteers on placebo. Although not recommended for pregnant women, if enprostil is given inadvertently to pregnant women with ulcers, it is unlikely to endanger the pregnancy during the first trimester.

Abortifacient Agents↗
PubMed1987

Male fetus with epignathus originating from the ethmoidal sinus.

Epignathus or teratoma arising from the hard palate nasal cavity is an extremely rare abnormality. This tumour usually causes death in neonatal life because of its location and because surgical removal is often impossible. We are presenting a case of epignathus originating from the ethmoidal sinus delivered at gestational week 29 by caesarean section due to increasing hydramniosis. The child died within a few minutes. Prenatal diagnosis is important for genetic counselling, obstetric management and, in some cases, neonatal surgery.

Adult↗
PubMed1987

Tissue-specific expression of human provirus ERV3 mRNA in human placenta: two of the three ERV3 mRNAs contain human cellular sequences.

Three polyadenylated RNAs, 9, 7.3, and 3.5 kilobases long, of a human endogenous retrovirus, ERV3, are abundant in human placental chorion, representing about 0.03 to 0.05% of the total mRNA. We characterized the structure of these mRNAs by Northern blot and S1 nuclease mapping analyses. We found that all three RNAs were spliced mRNAs that lacked 5.9 kilobases of proviral sequence, including the gag gene and most of the pol gene. In contrast to the transcription pattern usual for other retroviruses, the transcription pattern of the ERV3 provirus did not include a genome-length mRNA. All three of the ERV3 mRNAs initiated transcription at the same point in the 5' long terminal repeat (LTR) and contained identical splice junctions in the provirus. The 3.5-kilobase RNA was a typical subgenomic proviral mRNA, with its polyadenylation site in the 3' LTR. The two larger ERV3 mRNAs, however, extended through the polyadenylation site in the 3' LTR and were spliced at a second position approximately 370 nucleotides downstream from the 3' LTR. This finding suggests that when the ERV3 retrovirus integrated at this genomic locus in an ancestor of humans, it integrated within or adjacent to a cellular gene.

Base Sequence↗
PubMed1986

Effect upon the human myometrium during early pregnancy of prostaglandin E2 and its analogue 16-phenoxy-omega-17,18,19,20-tetranor-PGE2 methyl sulfonylamide.

A quantitative determination of the pharmacological effect of the prostaglandin analogue 16-phenoxy-omega-17,18,19,20-tetranor-PGE2 methyl sulfonylamide (16-phenoxy-PGE2) and the natural prostaglandin E2 has been made in vivo upon the human myometrium during early pregnancy. The method for the investigation, hysterometry, is based upon the concept that mechanical distension of smooth muscle induces contraction. The contractile response was recorded under basic conditions and during intravenous infusion of the active agent. It was found that the analogue had a 'potency' similar to or slightly more pronounced than the natural prostaglandin E2 when the comparison was made on a microgram basis.

Adult↗
PubMed1986

Effect upon the human myometrium during early pregnancy of the prostaglandin F2 alpha and its analogue 15(S)-15-methyl-PGF2 alpha.

The hysterometric technique has been designed to measure the pharmacological effect of active agents upon the human uterine muscle. The physiological background is the fact that smooth muscle contracts under the influence of mechanical stimulation. By applying hysterometry, the effects on the human myometrium in vivo during early pregnancy of the naturally occurring prostaglandin F2 alpha and its analogue 15(S)-15-methyl-PGF2 alpha have now been evaluated. According to the analysis of the contractile responses, the effects of the agents have been determined quantitatively. The drug effects have been characterized by changes in myometrial response between registrations under basic conditions and during the infusion of the active agent, respectively. It was found that when these drugs were given in the doses usually employed in clinical practice, the effect on contractility of the PGF2 alpha compound was more pronounced than that of the analogue. However, when describing the results on a microgram basis, the 15-methyl-PGF2 alpha was confirmed to be 10-20 times more potent than PGF2 alpha.

Adult↗
PubMed1985

Coexpression of the sis and myc proto-oncogenes in developing human placenta suggests autocrine control of trophoblast growth.

First trimester human placentas actively express the sis proto-oncogene, the structural gene for the B chain of platelet-derived growth factor (PDGF). Using the in situ hybridization technique, the 4.2 kb c-sis transcript has been localized to the cytotrophoblastic component, especially the highly proliferative and invasive cytotrophoblastic shell, paralleling the distribution of c-myc transcripts in early placenta. Explants of first trimester placenta release significant levels of PDGF-like activity into the medium under apparent developmental control. Moreover, cultured trophoblasts display abundant high-affinity PDGF receptors and respond to exogenous authentic PDGF by an activation of the c-myc gene and DNA synthesis. The developing human placenta may therefore represent a case of autocrine growth regulation in a normal tissue, in which cells bearing receptors for a growth factor can also synthesize and respond to that factor.

Cell Line↗
PubMed1985

Cell-type-specific pattern of myc protooncogene expression in developing human embryos.

The expression of viral oncogenes in cells transformed by acutely transforming retroviruses profoundly alters proliferation and differentiation in the target cell, suggesting that the cellular homologues of the viral oncogenes, the protooncogenes, have a role in normal cell proliferation and differentiation. To investigate the possible developmental role of protooncogenes in human embryogenesis, we have determined the spatial distribution of myc gene transcripts in early human embryos by using in situ hybridization of a labeled myc exon to thin sections. The results indicate a stage- and cell-type-specific regulation of c-myc gene expression in primarily epithelial cells of late first trimester embryos. Furthermore, the data suggest that the linkage between c-myc gene expression and cellular proliferation holds for only a restricted set of embryonic cells.

Cell Division↗
PubMed1985

Effect of pharmacologically active agents upon the human myometrium in vivo. Theoretical and technical aspects.

Smooth muscle is capable of contracting in response to mechanical distension. Even though the structural basis for this phenomenon is not completely clear, a method has been designed by which the contractile response to mechanical distension of the human uterine muscle can be determined in vivo. The distension is enforced sinusoidally within the frequency range 0.006-1 Hz, by filling and emptying a rubber balloon introduced into the uterine cavity. A tonometric index of the myometrium is defined using Hook's law after the approximate evaluation of a contratile modulus and the tangential stress and strain in the innermost layer of the uterine wall. The regression lines of tonometric indices upon frequency are determined and intercepts of the equations for basic conditions are compared with those obtained during the administration of pharmacologically active agents. In a pilot study, this system, now modified for the evaluation of drug effects during early pregnancy, has been tested and found reliable.

Female↗
PubMed1985

Effect of the naturally occurring prostaglandins E2 and F2 alpha on the human myometrium in vivo during pregnancy.

Hysterometry has been used to evaluate the effect on the human myometrium in vivo during early pregnancy of the naturally occurring prostaglandins E2 and F2 alpha. The hystermetric technique is based upon the fact that mechanical distension of smooth muscle induces contraction. According to the analysis of the contractile responses, the effects of the agents have been determined quantitatively. The drug effects have been characterized by changes in myometrial response between registrations under basic conditions and during the infusion of the active agent, respectively. It was found that when these drugs were given in the doses usually employed in clinical practice, the effect on contractility of the PGF2 alpha compound was more pronounced than that of the PGE2. However, when describing the results on a microgram basis, the PGE2 was confirmed to be more potent than the PGF2 alpha by a factor of up to 7-8.

Adult↗
PubMed1984

Spatial and temporal pattern of cellular myc oncogene expression in developing human placenta: implications for embryonic cell proliferation.

We have analyzed staged human placentas by Northern, dot blot, and in situ hybridization to human c-myc probes. Placental RNA exhibits a stage-specific appearance of a 2.4 kb transcript of the c-myc gene. The frequency of this transcript varies 20 to 30 fold over the course of placental development, showing a peak at 4-5 weeks after conception, where the myc transcripts comprise about 0.05% by weight of the total placental mRNA. A clear decline in placental c-myc transcription is seen before the end of the first trimester of pregnancy. In situ hybridization to 125I-labeled myc probes demonstrates an unequal spatial distribution of myc transcripts in placental with particularly high expression in the cytotrophoblastic shell of early placenta. Labeling of placental explants with 3H-thymidine, the localization of myc transcripts to cytotrophoblasts, and the temporal pattern of myc expression all support a strong correlation between myc transcript abundance and cytotrophoblast proliferation. We argue for a role for the c-myc gene in the proliferation of normal cells in this tissue.

Cell Division↗
PubMedDate not supplied

Temporal and spatial pattern of cellular myc oncogene expression during human placental development.

The human placental trophoblast component is of embryonic origin and is developmentally regulated; the tissue is highly proliferative and often described as pseudomalignant. Because cellular oncogenes have been implicated in normal cellular proliferation and differentiation processes, we have studied c-myc oncogene expression in relation to the progression of human placental development. The c-myc transcript shows a 20- to 30-fold variation over the course of placental development, with a peak at four to five weeks after conception. A clear decline in placental c-myc transcription is seen before the end of the first trimester of pregnancy. In situ hybridization to [125I]-labelled myc probes demonstrates an unequal distribution of myc transcripts in placenta, with particularly high expression in the cytotrophoblastic shell of the early placenta. The localization of myc transcripts to cytotrophoblast and the temporal pattern of myc expression support a strong correlation between myc transcript abundance and cytotrophoblastic proliferation. These findings are discussed in the light of a possible role for the c-myc gene in proliferation of normal cells.

Female↗