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Biomedical subjects

M Bygdeman

Publications and source records attributed to M Bygdeman.

At least 91 records · Page 5Linked to original sources

The effect of RU 486 administered during the early luteal phase on bleeding pattern, hormonal parameters and endometrium.

The purpose of the present study was to investigate the effect of a single dose of RU 486 administered very early in the secretory phase on endometrial development and levels of progesterone receptors, on plasma levels of gonadotrophins and ovarian hormones and on the pattern of menstrual bleeding. Twenty-four regularly menstruating subjects participated and were studied during a control, a treatment and a follow-up cycle. In the treatment cycle, a single dose of 200 mg RU 486 was given in the evening of the second day after the urinary LH peak. Plasma was collected from cycle day 10 until menstruation in both control and treatment cycles. The lengths of the control, treatment and follow-up cycles were equal. Three of the subjects had slight vaginal bleeding in association with RU 486 intake which, however, did not disturb their normal menstrual rhythm. Plasma levels of oestradiol, progesterone and FSH were not affected in the treatment cycle, whereas LH levels increased slightly. The elimination half-life of RU 486 was 28.6 h. An endometrial biopsy was taken 12, 36 or 84 h (LH + 3, LH + 4 and LH + 6) after drug intake (eight subjects in each group) and another biopsy was taken on the corresponding day in the control cycle. The specimens were assessed by morphometric analysis and for cytosolic progesterone receptor concentrations. Endometrial biopsies taken 12 h (on LH + 3) after RU 486 intake contained significantly (P less than 0.001) lower levels of cytosolic progesterone receptors than in the control cycle, but levels at 36 and 84 h were similar.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Electrophysiologic effects of ethanol in human brain xenografts in oculo: antagonism by Ro15-4513.

Human cortex cerebri and cerebelli xenografts from first-trimester fetal tissue fragments were used to study the effects of ethanol on single human central neurons. Transplants were placed into the anterior eye chamber of athymic nude rats and allowed to develop for 3 to 11 months. Immunohistologic analysis revealed graft structures that stained positively for a number of neuronal, transmitter-related, glial and vascular markers. Superfusion of ethanol (EtOH) elicited a reversible and dose-dependent depression of action potential discharge. At least two populations of neurons could be identified--a more sensitive group with an EC50 of 3.0 mM and a less sensitive group with an EC50 of 22.4 mM. These EtOH levels are within the range eliciting behavioral signs of intoxication in humans. EtOH-induced depressions could be antagonized by administration of the benzodiazepine inverse agonist Ro 15-4513. This study represents the first demonstration, to our knowledge, of the electrophysiologic actions of EtOH on single neurons from human brain, and provides dose-response data collected with known concentrations of EtOH as well as evidence for the blockade of these EtOH effects by the Roche compound.

Animals↗

Human fetal dopamine neurons grafted into the striatum in two patients with severe Parkinson's disease. A detailed account of methodology and a 6-month follow-up.

By using stereotaxic surgical techniques, ventral mesencephalic tissues from aborted human fetuses of 8 to 10 weeks' gestational age were implanted unilaterally into the striata in two patients with advanced Parkinson's disease. The patients were treated with a cyclosporine, azathioprine, and steroid regimen to minimize the risk for graft rejection. They were examined for 6 months preoperatively and 6 months postoperatively and continued to receive the same doses of antiparkinsonian medication. There were no significant postoperative complications. No major therapeutic effect from the operation was observed. However, in the clinical tests, both patients showed small but significant increases of movement speed for repeated pronation-supination, fist clenching, and foot lifting. The rate of walking also increased in the one patient tested. For both patients, there was an initial worsening postoperatively, followed by improvement vs preoperative performance at 1 to 3 months. Both patients also showed significant improvement in the magnitude of response to a single dose of levodopa (L-dopa), but there was no increase in the duration of drug action. The motor readiness potential increased in both patients postoperatively, primarily over the operated hemisphere. Neurophysiological measurements also showed a more rapid performance of simple and complex arm and hand movements on the side contralateral to transplantation in one patient at 5 months postoperatively. Positron emission tomography demonstrated no increased uptake of 6-L-(18F)-fluorodopa in the transplanted striatum at 5 and 6 months. Taken together, these results suggest that the fetal nigral implants may have provided a modest improvement in motor function, consistent with the presence of small surviving grafts. Although our results support further scientific experimentation with transplantation in Parkinson's disease, widespread clinical trials with this procedure are probably not warranted at this time.

Contingent Negative Variation↗

Human ventral mesencephalic xenografts to the catecholamine-depleted striata of athymic rats: ultrastructure and immunocytochemistry.

On the basis of animal studies, grafts of fetal human dopaminergic cells have been suggested as a therapy for Parkinson's disease. The purpose of this study was to characterize the ultrastructure and immunocytochemistry of human ventral mesencephalic xenografts placed into the catecholamine-depleted striata of athymic "nude" rats. Human fetal tissue was obtained from tissue fragments derived from elective abortions during the first trimester of pregnancy. Small pieces of the basal mesencephalon were grafted into the catecholamine-depleted striata of four athymic nude rats. The rats were allowed to survive from 3 to 6 months after grafting; following fixation, the striatal tissue containing the grafts was labeled with antibodies against tyrosine hydroxylase and serotonin. Immunocytochemistry revealed tyrosine-hydroxylase-like-immunoreactive (THLI) and serotoninlike-immunoreactive (5HTLI) cell bodies within the human grafts. Both 5HTLI and THLI fibers crossed the graft-host interface and innervated the previously lesioned striatum. Both types of fibers also entered the host cortex from the adjacent human graft. At the ultrastructural level, THLI and 5HTLI fibers and synaptic terminals were observed in the host neuropil. THLI and 5HTLI dendrites and axon terminals were also observed in the neuropil of the grafts themselves. THLI axon terminals are not normally present in the substantia nigra. The results of our study indicate that human xenografts can survive in the neuropil of the host striatum and form morphologically appropriate synapses within the host brain.

Animals↗

Human fetal spinal cord xenografts survive in the eye of athymic nude rat hosts.

Human fetal spinal cord tissue was recovered from elective abortions and grafted to the anterior chamber of the eye of adult athymic nude rats. The transplants slowly became vascularized from the host iris during the first months. There was a clear cut stage-dependent survival and growth along a more "human" time-table. Fetal spinal cord tissue from embryos younger than gestational week 8 showed a much better survival and growth than tissue from older stages. Using laminin immunohistochemistry blood vessels could be visualized in the grafts. The pattern of vascularization was, however, clearly abnormal; there were fewer vessels which had abnormally thick walls as compared to those in the normal spinal cord. Similar to rat spinal cord allografts the human spinal cord xenografts displayed a relative gliosis and were surrounded by a glial layer visualized with antibodies against glial fibrillary acidic protein. Neurofilament-immunoreactive fibres were found inside the glial layer. A variety of neurons were found including large polygonal motoneuron-shaped cells, albeit with CGRP and AChE negative cell bodies. Both Substance P and enkephalin-immunoreactive cells and fibres were found. It is concluded that xenografted fetal human spinal cord survives, grows and may provide a useful model for experimental studies of human spinal cord development and connectivity.

Animals↗

Vascular changes in the human endometrium following the administration of the progesterone antagonist RU 486.

Eleven healthy women were assigned to one of two groups. They received 50 mg RU 486 orally per day either on cycle days 7 to 10 (preovulatory group n = 5) or on cycle days 20 to 23 (postovulatory group, n = 6). An endometrial biopsy was taken on the fourth day of the RU-treatment in the preovulatory group and on the second (n = 2) or fourth (n = 4) treatment day in the postovulatory group. Biopsies from 34 untreated women representing matched samples from early and mid preovulatory phase (n = 10) and mid and late postovulatory phase (n = 24) were used as control. The ultrastructure of the endometrial capillaries was investigated by morphometric methods. The administration of RU 486 during the preovulatory phase did not modify the vascular structure. However, when given in the postovulatory phase, necrosis occurred in the capillary endothelial cells with and without regressive changes of the adjacent stroma. The area and diameter of the capillary lumen and the area of the adventitia was smaller than in the control material (p less than 0.01). The result of the study suggests that RU 486, when administered in the postovulatory phase, directly affects the capillary vessels of the endometrium.

Adult↗

The use of prostaglandins and antiprogestins for pregnancy termination.

Although vacuum aspiration could be regarded as a simple procedure, complications do occur and attempts have been made to develop non-surgical procedures for termination of pregnancy during the first 3-4 weeks following the first missed menstrual period. A variety of prostaglandin (PG) analogs have been developed which are equally effective as vacuum aspiration to induce abortion during early pregnancy. However, the widespread acceptance of PG treatment is limited by a relatively high incidence of gastrointestinal side effects and uterine pain. Treatment with presently available antiprogestins alone is not sufficiently effective to compete with vacuum aspiration. However, administration of these compounds induces uterine contractions and increases the sensitivity of the myometrium to prostaglandin. These effects allow the development of sequential treatment with RU 486 and a low dose of PG analogs administered intramuscularly or vaginally which is highly effective and is seemingly associated with a lower frequency of side effects than if PG analogs are used alone. It can be concluded that this medical abortion method has the capacity to compete with vacuum aspiration for termination of early pregnancy. Randomized studies comparing the two procedures are, however, needed to confirm this statement.

Abortifacient Agents↗

15-Keto-13,14-dihydroprostaglandin E2- and F2 alpha-metabolite levels in blood from men and women given prostaglandin E2 orally.

Prostaglandin E2 (PGE2) was administered orally in a dose of 1 mg to healthy males (n = 20) and females (n = 10). Blood levels of 15-keto-13,14-dihydroprostaglandin F2 alpha (PGF2 alpha-M) and 15-keto-13,14-dihydroprostaglandin E2 (PGE2-M), determined as the rearrangement product 11-deoxy-15-keto-13,14-dihydro-11 beta, 16-cycloprostaglandin E2 (PGE2-cyclo-M), were measured. The levels of the two PG metabolites increased already 10 minutes after ingestion of the tablet and the mean peak value for PGE2-cyclo-M in the men was 4.64 nmol/l which was reached 50 minutes after PGE2 administration. The mean peak value in women was 4.99 nmol/l which was obtained after 30 minutes. The increase in PGE2-cyclo-M concentration was significantly faster (p less than 0.05) in women than in the men. The mean plasma concentration of PGF2 alpha in males were 0.20 nmol/l prior to treatment and rose after PGE2 ingestion to mean peak level of 0.84 nmol/l after 70 minutes. The corresponding values for the females were 0.18 nmol/l and 0.88 nmol/l 50 minutes into treatment. When the data from both sexes were amalgamated PGE2-cyclo-M peak levels were reached significantly (p = 0.004) sooner than the PGF2 alpha-M peak. The two PG metabolites returned to baseline levels in 70% of the individuals after 240 minutes. The increase in PGF2 alpha-M concentration following oral administration of PGE2 indicates that part of the PGE2 was reduced to PGF2 alpha.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗

Morphological and electrophysiological studies of human hippocampal transplants in the anterior eye chamber of athymic nude rats.

Human fetal hippocampal tissue from normal women was obtained following elective abortion in the 8th to the 11th week of gestation. The hippocampal tissue was transplanted to the anterior chamber of the eye of adult athymic nude rats, where it was allowed to develop for up to 9 months before histological and electrophysiological evaluation. The transplants were revascularized from the host iris and many grew extensively in oculo. Large neurons were present in all transplants. Immunohistochemical studies revealed glutamic acid decarboxylase-containing terminals and clusters of gamma-aminobutyric acid-positive nerve cell bodies within the transplants, as well as scattered tyrosine hydroxylase-positive and acetylcholinesterase-containing fibers. Single neurons recorded extracellularly from transplants 4-9 months in oculo showed a slow spontaneous discharge, with both complex and single action potentials. Stimulation of the transplant surface evoked a small initial wave followed by a larger and longer-lasting field potential, similar to that seen in hippocampus in situ. A conditioning-testing paradigm was used to evaluate the presence of inhibitory circuitry in the hippocampal transplants. Significant suppression of the evoked test response was seen with interstimulus intervals ranging from 20 to 500 ms. Superfusion of enkephalin (100-300 nM) or penicillin (1600 U/ml) increased slow-wave activity, as did tetanic electrical stimulation. These treatments appeared to generate ictal-like activity, which in some cases persisted as interictal spikes. Illumination of the retina also increased neuronal activity, presumably by reflex activation of cholinergic afferents from the parasympathetic innervation of the iris. Taken together, our data suggest that fragments of hippocampus from aborted first trimester human fetuses, grafted to the eye chamber of rodent hosts, develop many organotypic histological and physiological features. This preparation may provide a unique means for the study of neurobiological properties of human brain in both normal and disease states.

Animals↗

Effect of oral prostaglandin E2 on uterine contractility and outcome of treatment in women receiving RU 486 (mifepristone) for termination of early pregnancy.

It has been shown that the antiprogestin RU 486 (mifepristone) increases the sensitivity of the early pregnant human uterus to the stimulatory action of synthetic prostaglandin E (PGE) analogues. To examine if RU 486 also increases uterine sensitivity to the naturally occurring PGE2 given orally, two investigative approaches were used in the present studies: (i) direct registration of uterine contractions before and after PGE2 administration in untreated and RU 486-treated early pregnant women; and (ii) a double-blind, randomized, controlled efficacy trial involving treatment of pregnant women (amenorrhoea of less than or equal to 49 days) with RU 486 (25 mg twice daily for 4 days) and PGE2 (1 mg once or twice) or placebo on the last day of RU 486 treatment. The results indicate that oral PGE2 at the doses employed had little or no stimulatory effect on uterine contractility and that it did not improve the rate of complete abortion achieved with RU 486 alone. Overall, 25 of 42 women (59%) had a complete abortion, 15 women (36%) did not abort and the remaining two had incomplete abortions. Women with complete abortions had significantly lower pretreatment levels of progesterone and a longer duration of induced bleeding than those who did not abort. Thus oral PGE2, when given in clinically acceptable doses, is not a suitable alternative to synthetic PGE analogues for use in combination with RU 486 for termination of early pregnancy.

Abortifacient Agents↗

Variation in, and inter-relationship between, prostaglandin levels and other semen parameters in normal men.

In each of 135 ejaculates from 46 healthy men, semen volume, various sperm parameters and the level of prostaglandins (PGs) were determined. Data were analysed to determine the within- and between-subject variability, the effect of abstinence period and the correlation between different parameters. Data which did not reveal a Gaussian distribution were transformed logarithmically. For all variables the between-subject variance exceeded the variation within subjects (P less than 0.001). Variation in time of abstinence between 1 and 3 days influenced semen volume and sperm content as well as the content of 19-hydroxylated PGs, but did not affect sperm motility or the concentration of PGE or PGF. A significant negative correlation was found between the seminal content of PGE and PGF and the total sperm count as well as the sperm concentration. Sperm motility was related to the balance between the content of 19-hydroxy PGE and 19-hydroxy PGF but not to their separate concentrations. The ratio between 19-hydroxy PGE and 19-hydroxy PGF did not change when the time of abstinence differed. Synthesis of the two 19-hydroxylated PGs seemed to be regulated by the same mechanism, but their hydroxylation capacity still varied considerably between individuals.

Humans↗

Prostaglandins and antiprogestins.

There is considerable interest in the development of a non-surgical method to terminate early pregnancy. During the three weeks immediately following the first missed menstrual period, several prostaglandin (PG) analogs such as sulprostone, gemeprost and 9-methylene PGE2 have been used to terminate the pregnancy. Prostaglandins, however, at the doses required to induce disruption of the conceptus cause gastrointestinal side effects and uterine pain which are more severe than those subsequent to vacuum aspiration. Treatment with the antiprogestin, mifepristone counteracts the effects of progesterone in pregnancy and thus prevents maintenance of the pregnancy. Mifepristone administered alone causes termination of the pregnancy in most, but not all, cases. In addition to removing the influence of progesterone, mifepristrone also induces regular uterine contractions and significantly increased the sensitivity of the uterus to PG analogs. Mifepristone (50 mg/day) followed by an intramuscular injection of a low dose, (0.25 mg), of sulprostone (approximately 1/6 of the dose of prostaglandin necessary to induce abortion if used alone) was highly effective in terminating early pregnancy, causing complete abortion in 94% of cases. Gastrointestinal side effects were rare and uterine pain significantly less common than if PG analogs were used alone. Subsequently the combination of mifepristone and vaginal administration of gemeprost (0.5-1.0 mg) has been shown to be equally effective Ideally, the PG analog would be administered orally rather than by injection or vaginal administration. Preliminary data indicate that 9-methylene PGE2 but not PEG2 may be suitable for this purpose in combination with mifepristone.(ABSTRACT TRUNCATED AT 250 WORDS)

Abortifacient Agents, Nonsteroidal↗

The effect of tamoxifen on the function and lifespan of the corpus luteum and on subsequent ovarian function.

The aim of the present study was to investigate the effects of tamoxifen on pituitary and luteal function and on the bleeding pattern when administered continuously in the secretory phase. The study included 16 women with regular menstrual cycles followed during one control, one treatment and one follow-up cycle. Each volunteer received 20 mg tamoxifen twice daily from cycle day 18 to menstruation in the treatment cycle. The luteal phase was slightly, but significantly prolonged during treatment, and FSH, progesterone, 17-hydroxyprogesterone, 20 alpha- dihydro progesterone, estrone, estrone sulphate and estradiol significantly elevated in comparison with corresponding data during the control cycle. The results indicate that estrogen may be of some importance for the regulation of the life span of the corpus luteum in the human. The significantly elevated levels of pregnanediol glucuronide and estrone glucuronide during the follow-up cycle are most likely a result of either a direct effect of remaining circulating tamoxifen levels on the ovary, or mediated through the increased release of FSH. If estrogens are of importance for the process of implantation, which has recently been suggested in sub-human primates, also in the human remains unclear. Studies on the effect of anti-estrogens on the endometrium during the secretory phase of the cycle are ongoing.

17-alpha-Hydroxyprogesterone↗

Termination of early pregnancy with RU 486 (mifepristone) in combination with a prostaglandin analogue (sulprostone).

The antiprogestin RU 486 (mifepristone) has been shown to induce abortion when administered in early pregnancy, but the rate of incomplete abortion is high, around 40%. As blockage of the progesterone receptor increases the myometrial sensitivity to prostaglandins, a combination of RU 486 and a prostaglandin E2-analogue was tested for termination of pregnancy. One hundred and sixteen women, with a gestational length of less than 49 days from the first day of the last menstrual period, were treated with a daily dose of 50 or 100 mg RU 486 for 3 to 6 days, complemented with an intramuscular dose of 0.25 mg sulprostone (16-phenoxy-PGE2-sulfonylamide) on the last day of RU 486 treatment. The results confirmed that a reduction of treatment duration to 3 days is just as effective for inducing abortion (91% complete abortion) as a 4-6-day treatment regimen (95% complete abortion). Six patients had an incomplete abortion and in one the pregnancy continued unaffected. Side effects included intense uterine pain after the prostaglandin administration (16%), vomiting associated with the antiprogestin intake (9%) and after the prostaglandin administration (9%). One woman needed emergency curettage due to heavy bleeding. Six percent of the treated patients had a decrease in hemoglobin exceeding 20 g/l during the first week but no patient needed blood transfusion. No serious side effects were recorded.

Abortifacient Agents↗