Pregnancy-induced hypertension is associated with down-regulation of Kir6.1 in human myometrium

It is generally accepted that activity of K⁺ channels maintain resting membrane potential and uterine quiescence during pregnancy, which is, at least in part, mediated by down-regulation of ATP-sensitive K⁺ (K_ATP) channels. Pregnancy-induced hypertension (PIH) is associated with pre-term and late pre-term labour. Here, we have used real time RT-PCR to compare mRNA levels of K_ATP channel subunits in PIH parturient and control parturient. We have found that Kir6.1, a pore forming, myometrial K_ATP channel subunit is down-regulated in PIH patients. This could perfectly explain increased rate of pre-term labour in patients suffering from PIH.

Toxic Metal and Trace Element Concentrations in Blood and Outcome of In Vitro Fertilization in Women

The aim of this study was to investigate the association of trace element and toxic metal concentrations in blood and the outcome of in vitro fertilization (IVF). The study included 104 consecutive patients that underwent assisted reproductive technology (ART) procedures. The following parameters were determined: cadmium (Cd), mercury (Hg), arsenic (As), and lead (Pb); and copper (Cu), zinc (Zn), selenium (Se), and magnesium (Mg). Serum samples were obtained before commencing stimulation. Patients with smoking habit had significantly higher Pb concentrations (P = 0.022), as well as higher concentrations of As and Hg but not significantly. All subjects were divided into groups of pregnant and nonpregnant patients. Pregnant patients had lower mean values of Mg (P = 0.009), As (P < 0.05), and Pb (P = 0.034), compared to nonpregnant, and a significant correlation between pregnancy outcome and concentrations of Mg, Cd, and Pb was found. Women who had had delivered had lower Mg (P = 0.009) and Cd (P = 0.014) concentrations. There was a significant correlation of the negative outcome of IVF procedure with higher concentrations of Pb (P = 0.046) and Cd (P = 0.012). In conclusion, our results suggest that there is a difference in Mg, Pb, and Cd concentrations between pregnant and nonpregnant women. There was no association between toxic metals and number and quality of oocytes and embryos, while there was with fertilization rate. Concerning trace elements, we did not find the correlation of trace elements with oocyte number and quality, nor with a number of fertilized oocytes, except for Cu. Patients who were pregnant had lower concentrations of Mg.

Oxidative Stress Markers in GnRH Agonist and Antagonist Protocols in IVF

BACKGROUND

Our aim was to study the effect of GnRH agonist and antagonist protocols of ovarian stimulation on oxidative stress parameters in serum and the influence of oxidative stress parameters change on the outcome of IVF cycles.

METHODS

This prospective study included 82 patients who underwent IVF procedures. We determined SOD, MDA and SH groups in serum. Serum samples were obtained between the second and fourth day of the cycle and on the day of HCG administration during ovarian stimulation.

RESULTS

Patients were divided into two groups depending on the protocol of stimulation. The mean total and mature oocytes number and number of fertilized oocytes were higher in GnRH agonist group. There was no significant difference in biochemical pregnancy, miscarriage and live-birth rate in both groups. Mean serum SOD was significantly lower, while mean serum MDA and SH groups were significantly higher after ovarian stimulation. Delivery rate was higher in patients without OS while miscarriage rate was higher in patients with OS.

CONCLUSIONS

Our study confirmed that there is a difference in the concentration of oxidative stress parameters before and after ovarian stimulation. IVF outcome is better in patients without OS after ovarian stimulation. However, the protocol of ovarian stimulation is neither associated with a change in oxidative stress parameters nor with the outcome of ART procedures.

KATP channels are up-regulated with increasing age in human myometrium

It is well established that ageing is associated with decrease in myometrial efficiency and higher incidence of labour complications. In myometrium, the presence of ATP-sensitive K+ (KATP) channels has been detected and they could be a factor in regulating uterine quiescence in pregnancy and contractions during labour. Here, we have examined a possibility of ageing-mediated regulation of KATP channels in the human myometrium. Myometrial samples were taken from non-pregnant women undergoing hysterectomy (n=34) and from women undergoing caesarean section in late pregnancy (n=36). Real time RT-PCR revealed that mRNAs of all known KATP channel subunits were present in the human myometrium. In non-pregnant myometrium, ageing up-regulated SUR2B/Kir6.1, subunits forming KATP channels in this tissue, without affecting the expression of other channel subunits. In the late pregnant myometrium, the level of subunits that do not form functional KATP channels was not affected by age within 20-41 age range. However, uterine SUR2B and Kir6.1 were up-regulated in parturient over 35 years. An ageing-induced increase in those channel subunits was confirmed by Western blotting. Thus, this study suggests that KATP channels are up-regulated with increasing age in human myometrium. This may help explain, at least partially, increased rate of birth complications in women aged over 35 years.

Effects of tibolone on the risk factors for cardiovascular diseases in postmenopausal women

Background/Aim. Tibolone is a preparation that belongs to the group of steroidal substances. The effects of the use of the use of tibolone are the consequence of the activities of its metabolities, considering that their hormonal activity depends on the type of tissue in which they develop. The aim of this study was to evaluate the influence of the use of tibolone on risk factors for the development of cardiovascular diseases in postmenopausal women. Methods. A prospective observational stady included 94 patients who had the concentration of l7? estradiol < 50 pg/ml, and who was in menopause more than a year. Out of the total number of patients, 63 accepted to receive tibolone 2.5 mg daily (tibolone group), while 31 of the patients refused to take tibolone (control group). We measured the concentration of lipids (cholesterol, LDL cholesterol, HDL cholesterol, triglicerides), antitrombin III, fibrinogen, and C-reactive protein, before and after the treatment within a 6-month period. Then, we compared the difference between the values of concentrations and tested the statistical significance of the difference. We also evaluated the changes of values in the concentrations of the examinated parameters inside a 6-month period in the control group. Results. In 31 patients of the control group, from the control group there were no significant changes in the values of the defined parameters as compared to their initial values after six months. But there were changes of statistical significance (p < 0.001) in values of the concentrations of the exeminated parameters before and after the treatment in the tibolone group. In fact, we recorded decreases in the total cholesterol by 17.8%, HDL cholesterol by 27%, LDL cholesterol by 4% (without statistical significance p > 0.05) and triglicerids by 35%. There were no statistical differences in the concentrations of antitrombin III, fibrionogen, and C-reactive proteine in the tibolone group before and after the treatment. Conclusion. The use of tibolone dose decrease the concentration of the total cholesterol, triglicerides, HDL cholesterol, without a significant decrease of LDL cholesterol. Also, the use of tibolone does not have any significant effect on the concentrations of antitrombin III, fibrinogen and C-reactive proteine. The number of serum parameters measured in this study was limited, thus that was the reason to discuss only about the metabolism of lipids in the patients from the tibolone group. The final conclusion about the risk for cardiovascular diseases in the patients on tibolone, howerer, reqnires were extensive further clinical exeminations.

Medicamentous abortion with mifepristone and misoprostol in Serbia and Montenegro

Background/Aim. Medicamentous abortion was first introduced in Serbia and Montenegro in September 2001. The aim of this study was to assess the efficiency, side effects, and acceptability of medicamentous abortion using mifeprostone orally (600 mg), and 48 hours later, misoprostol both orally and vaginally in different regiments in our population (400 mcg, 600 mcg, 800 mcg). Methods. A total of 235 consecutive women with pregnancies up to 49 days of gestational age were assigned to 4 groups according to the different misoprostol regiment (group I 400 mcg, group II 600 mcg, group III 800 mcg orally, and group IV 800 mcg both orally and vaginally). The principal outcome measure was a successful abortion defined as a complete expulsion of intrauterine contents without a need for surgical intervention 14 days after the procedure. Other outcome measures were the following: drug related effects, and adverse effects related to the abortion process. Results. In general, the success rate was 50%, 89.48%, 75% and 92.11% in the groups I, II, III, and IV, respectively, as judged by the complete expulsion of the intrauterine contents without surgical intervention (t1:4 = 7.005; t2:4 = 0.3872, t3:4 = 2.9784, p < 0.01). The incidence of adverse effects (vomiting, abdominal pain, bleeding, and fever) was low in general, but among our groups it occurred mostly with the higher doses of orally applied misoprostol (800 and 600 mcg). Only one case required urgent curettage for heavy vaginal bleeding, and two blood transfusions, as well. No cases of intact pregnancies were recorded in the study. Conclusion. Our study showed that a mifepristone dose of 600 mg orally, and misoprostol 400 mcg orally and 400 mcg vaginally were most effective. Thus, a combination of mifepristone and misoprostol for medicamentous abortion should take a higher proportion in the termination of early pregnancy in our population.

Predominant role for nitric oxide in the relaxation induced by vasoactive intestinal polypeptide in human uterine artery

It has been previously shown that vasoactive intestinal polypeptide (VIP) induces endothelium-dependent relaxation of the human uterine artery. However, the nature of the mediator of the VIP-induced endothelium-dependent relaxation of the human uterine artery has not yet been determined. Therefore these experiments were undertaken to examine the effects of VIP on human uterine arteries and to establish the role of various endothelial factors on the relaxation induced by VIP. The experiments were performed on isolated human uterine arterial rings. VIP (0.3-100 nM) induced a concentration-dependent relaxation of human uterine arteries with intact endothelium (pEC50 = 8.06+/-0.14, n = 28). After the removal of the endothelium this relaxation was abolished (n = 6). Indomethacin (10 microM), a cyclooxygenase inhibitor, and diethylcarbamazine (100 microM), a lipoxygenase blocker, had no effects on VIP-induced relaxation. In contrast, methylene blue (10 microM), a blocker of guanylate cyclase, NG-monomethyl-L-arginine (10 microM), an inhibitor of nitric oxide (NO) synthase, and 4-aminopyridine (1 mM), a non-selective blocker of K+ channels, antagonized the effect of VIP with suppression of maximal VIP-induced relaxation. Non-competitive antagonism with methylene blue revealed that the pKa value for VIP-receptor complex was 8.10+/-0.10 (n = 6) and the receptor reserve expressed as KA/EC50 was 0.89+/-0.11, where pKa = log10KA, and KA is the dissociation constant of VIP-receptor complex. Therefore, on the basis of the results presented, we can conclude that VIP induces endothelium-dependent relaxation in human uterine arteries, acting as a partial agonist on this blood vessel. It appears that endothelium-dependent relaxation induced by VIP in human uterine artery can be entirely explained by the release of NO from endothelial cells.

Effect of oxytocin as a partial agonist at vasoconstrictor vasopressin receptors on the human isolated uterine artery

1. The effect of oxytocin on endothelium-intact and endothelium-denuded segments of the human uterine artery rings was investigated. 2. In both types of preparation oxytocin induced contraction of human uterine artery with similar potency and efficacy (pEC50 values: 6.95 +/- 0.05 vs 7.06 +/- 0.01; maximal response values: 61 +/- 4.1% vs 63 +/- 5.1% for arteries with and without endothelium, respectively). 3. In contrast, human uterine arteries, both intact and denuded of endothelium, did not respond to the addition of the selective oxytocin receptor agonist, [Thr4, Gly7]oxytocin (10 nM(-1) microM). 4. The vasopressin receptor antagonists, [d(CH2)5Tyr(Me)]AVP (10-100nM) and [d(CH2)5,D-Ile2,Ile4]AVP (300 nM-3 microM) produced parallel rightward shifts of the curves for oxytocin. The Schild plots constrained to a slope of unity gave the following -log K(B) values: [d(CH2)5Tyr(Me)] AVP vs [d(CH2)5,D-Ile2,Ile4] AVP 9.24 vs 6.91 and 9.26 vs 6.84 for human uterine artery with intact and those denuded of endothelium, respectively. In contrast, in both types of preparations the oxytocin receptor antagonist, [d(CH2)5Tyr(OMe), 2Orn8]vasotocin (1 microM), did not significantly affect oxytocin-induced contractions. 5. The calculated pK(A) values for oxytocin itself also did not differ between preparations: 6.56 and 6.43 for human uterine artery with and without endothelium, respectively. In both types of preparations, the receptor reserve (K(A)/EC50) was close to unity (intact vs denuded: 3.9 vs 3.0). 6. It is concluded that, in human uterine artery, oxytocin induces contractions that are not modulated by the endothelium. It is likely that oxytocin acts as a partial agonist on human uterine artery, regardless of the endothelial condition. On the basis of differential antagonists affinity and affinity of oxytocin itself, it is probable that receptors involved in oxytocin-induced contraction in human uterine arteries belong to the V(1A) vasopressin receptors.

Indomethacin reduces contraction of isolated non-pregnant human uterine artery induced by prostaglandin F2 alpha

The purpose of this study was to explore whether cyclooxygenase products derived from endothelium or vascular smooth muscle participate in the response of human uterine artery to prostaglandin F2 alpha. Experiments were performed using human uterine arterial rings. Prostaglandin F2 alpha (0.4 nM-1 microM) induced contraction of human uterine arteries with both intact and denuded endothelium with similar potency and efficacy (pD2 values: 7.93 +/- 0.01 and 8.07 +/- 0.03 for vessels with and without endothelium respectively; maximal response values: 89.1 +/- 4.7% and 92.3 +/- 3.8% for vessels with and without endothelium respectively). Indomethacin (10 microM) significantly suppressed the maximum effects of prostaglandin F2 alpha and induced a shift towards the right of the prostaglandin F2 alpha concentration-response curves, regardless of the endothelial condition. On the other hand, in both types of preparations, OKY-046 (10 microM), an inhibitor of thromboxane synthesis, did not affect prostaglandin F2 alpha-induced contraction of human uterine arteries. It is concluded that in human uterine artery prostaglandin F2 alpha-induced contraction is mediated, at least in part, through constrictor prostanoid(s) of vascular smooth muscle origin that is not thromboxane A2.

Relaxation of human uterine artery in response to pinacidil: predominant role for ATP-dependent potassium channels

The effect of pinacidil on human isolated uterine artery rings was investigated. Pinacidil (10 nM-300 microM) induced a concentration-dependent relaxation of the precontracted arterial segments (pD2: 6.26; maximal response: 98.5%). Apamin (1 microM) and tetraethylammonium (6 mM) had no effects on the pinacidil-evoked relaxation, while 4-aminopyridine (0.1-6 mM) and glibenclamide (1-10 microM) competitively antagonized the response to pinacidil. The dissociation constants for 4-aminopyridine and glibenclamide were 240 microM and 0.40 microM, respectively. It is concluded that, in human uterine arteries, pinacidil induces relaxation. On the basis of differential antagonist affinities, we suggest that pinacidil produces a relaxation of this blood vessel through activation of glibenclamide-sensitive, ATP-dependent potassium channels.

Endothelium-dependent relaxation in response to acetylcholine in the human uterine artery

The effect of acetylcholine on isolated human uterine artery rings was investigated. Acetylcholine induced concentration and endothelium-dependent relaxation (pD2 = 7.29 +/- 0.03) of the precontracted arterial segments. The dissociation constant (KA) for acetylcholine was 1.35 (0.92-1.77) mumol/l. The occupancy-response relationship was non-linear. Half-maximal response to acetylcholine was obtained with 5.25% receptor occupancy. Muscarinic receptor antagonists: atropine, pirenzepine, methoctramine, p-fluoro-hexahydro-sila-diphenidol (pFHHSiD) and 4-diphenyl-acetoxy-N-methyl-piperidine (4-DAMP) competitively antagonized the response to acetylcholine. The constrained pA2 values were 9.32 +/- 0.03, 7.13 +/- 0.01, 6.26 +/- 0.01, 8.17 +/- 0.01 and 9.13 +/- 0.02, respectively. A selective muscarinic M2 receptor antagonist, gallamine, had no effect on acetylcholine-induced relaxation. It is concluded that in human uterine arteries acetylcholine induces endothelium-dependent relaxation and acts as a full agonist. We suggest that the muscarinic receptors involved in the acetylcholine-induced relaxation of the isolated human uterine artery are predominantly of the M3 subtype.

L-arginine induces relaxation of human uterine artery with both intact and denuded endothelium

The effect of L-arginine on isolated human uterine artery rings was investigated. L-Arginine, but not D-arginine, induced concentration-dependent relaxation. Removal of the endothelium enhanced the relaxant effects of L-arginine. Methylene blue and dexamethasone non-competitively inhibited L-arginine-induced relaxation, while NG-monomethyl-L-arginine competitively antagonized the response to L-arginine. Calmidazolium did not affect relaxation evoked by L-arginine. The dissociation constants obtained for L-arginine and NG-monomethyl-L-arginine in intact rings were not significantly different from those in endothelium-denuded rings. It is concluded that the relaxation induced by L-arginine in human uterine artery is mediated by non-endothelial nitric oxide production. We suggest that the NO synthase mediating the L-arginine-induced relaxation is an inducible type.

Predominant role for nitric oxide in the relaxation induced by acetylcholine in human uterine artery

The effect of acetylcholine on the isolated human uterine artery rings was investigated. Acetylcholine (10(-10) M to 6 x 10(-5) M) induced concentration- and endothelium-dependent relaxation (pD2 = 7.4 +/- 0.02, maximal response was 77.5 +/- 6.3% of relaxation induced by papaverine at 3 x 10(-4) M) of the pre-contracted arterial segments. Indomethacin (10(-5) M), diethylcarbamazine (10(-4) M) and tetra-ethylammonium (3 x 10(-4) M) had no effects on acetylcholine-evoked relaxation. Methylene blue (10(-5) M) and NG-monomethyl-L-arginine (L-NMMA) (3 x 10(-6) to 3 x 10(-5) M) antagonized relaxation induced by acetylcholine. The inhibition of endothelium-dependent relaxation by L-NMMA (10(-5) M) was reversed by L-arginine (10(-5) M) but not by D-arginine (10(-4) M). It is concluded that in uterine artery acetylcholine induces endothelium-dependent relaxation of isolated uterine artery is probably mediated via endothelial nitric oxide formation.

[Drug therapy of Graves' disease in pregnancy]

An analysis was made of 75 pregnant patients who received medicamentous therapy for Graves' disease before the investigated pregnancy and 20 healthy pregnant women with normal pregnancies and term delivery. A severe form of hyperthyreosis was found in 35 examined persons. A separate analysis was made of the patients who had no previous therapy (17) and pregnant patients who were treated with antithyroid drugs (18), with the aim to investigate their effect on the course and outcome of pregnancy and the condition of the newborn infant. In all examined pregnant women the median values with standard deviations for TSH, T4 and T3 in each trimester of pregnancy, the dynamics of their trends, as well as the correlation of values in treated and untreated pregnant women were recorded. The analysis of the pregnancy course in patients with hyperthyreosis indicated a significantly higher incidence of gestational diabetes and EPH gestoses (p less than 0.001). A separate analysis indicated that hyperthyreoidism is one of the risk factors in the occurrence of gestational diabetes. There were 90% of pregnant women who were delivered in an euthyroid condition achieved before pregnancy and maintained during pregnancy, 85% with mild and 77.1% with severe hyperthyreosis. The comparison of treated and untreated patients indicated that the percentage of delivered patients is similar (77.8:76.4), while the incidence of spontaneous abortions was higher (16.7:11.8) and of fetal deaths lower (5.5:11.8). There was one stillbirth in an untreated patient, while the remaining infants were healthy. The authors are of the opinion that it is necessary to achieve remission before pregnancy. In patients with severe hyperthyreosis the authors suggest the administration of antithyreoid drugs.

[Thyroid gland function during pregnancy]

In order to examine the thyroid gland function we analysed healthy pregnant women (20) with normal pregnancy course and term delivery, who had normal endocrinological findings before the investigated pregnancy. In all patients TSH, T4 and T3 concentrations were radioimmunologically determined by trimester, median values with standard deviations were analysed in order to establish normal values during gravidity, as well as the possible changes in relation to non-gravid condition. We determined that T4 (29.3%) and T3 (23.5%) concentrations significantly increased and that TSH insignificantly decreased (12.1%) in the first trimester of pregnancy. In healthy pregnant women during the advance of gestation there was a significant increase of T4 and T3, which was significantly higher in the following than in the previous trimester. TSH concentrations during pregnancy gradually decreased but the decrease during the whole course of pregnancy, and in separate trimesters, was not found to be statistically significant.

[Hematoma of the parametrium due to birth trauma]

From 1973 to 1980, assisting 59,068 vaginally completed deliveries, the authors encountered 19 hematomas of the parametrium (0.032%). Labour was prolonged in 13 out of these 19 cases and the instruments applied were the outlet forceps in 6 and the vacuum extractor in 2 cases, while the expulsion of the child in 5 cases was helped by an intravenous injection of Syntocin. Half the parturients were in the third and half in the fourth decade of their life; a third of them were primiparae. Clinically the picture of atony or uterine rupture prevailed. In the development of the hematoma of the parametrium a large number of etiological factors are to be pointed out: birth injury, parity, age, predisposition, and others. In 6 women subtotal hysterectomy, in 4 the ligature of the uterine artery, and in 5 the evacuation of the hematoma were applied, while in the remaining ones the treatment as conservative.