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Biomedical subjects

G Falkay

Publications and source records attributed to G Falkay.

At least 55 records · Page 3Linked to original sources
PubMed1989

Variations in prolactin secretion in hyper- and normoprolactinaemia with or without galactorrhoea.

The circadian variations and secretory rhythms in prolactin secretion were examined in 10 hyperprolactinaemic and 10 normoprolactinaemic women with or without galactorrhoea in order to establish a clearer picture of this secretion and to find, if exists, correlation between the prolactin level and galactorrhoea. In the normoprolactinaemic women a rhythmical rise and fall were observed within 20 min, with higher values during nocturnal sleeping; these changes were more marked in the galactorrhoeic group. In the hyperprolactinaemic group the diurnal and pulsation changes were less pronounced, galatorrhoea usually being accompanied by a higher degree of hyperprolactinaemia. In galactorrhoeic patients with a normal basal prolactin level, a relative prolactin excess may be reckoned with at certain times. A proportion of these women can in fact then be regarded as hyperprolactinaemic. In the hyperprolactinaemic cases without galactorrhoea, a decreased prolactin sensitivity and milk-forming ability of the breasts may be assumed.

Adult↗
PubMed1988

Beta-adrenergic receptors of lymphocytes in children with allergic respiratory diseases.

The beta-adrenergic receptor binding sites on peripheral lymphocytes in children with bronchial asthma (n = 16) and seasonal allergic rhinitis (n = 8) were examined in comparison with normal controls (n = 18) by means of 124I-cyanopindolol. The number of beta-adrenergic receptors was significantly lower in the asthmatic group (858 +/- 460/lymphocyte) than in the controls (1564 +/- 983/lymphocyte). The value (1891 +/- 1502/lymphocyte in children with allergic rhinitis was slightly higher than that in healthy controls. Of the 24 patients suffering from allergic diseases of the lower or upper airways, the bronchial histamine provocation test was performed in 21; 16 gave positive results, while 5 were negative. No difference in beta-adrenergic receptor count was found between the histamine-positive and negative patients. Neither was there any correlation between the number of beta-adrenergic receptors and the high (16/24) and low (8/24) serum IgE concentrations found in allergic patients. The significant decrease in beta-adrenergic receptor count in asthmatic children lends support to Szentiványi's concept. Further qualitative and quantitative analysis of lymphocyte beta-adrenergic receptors may provide an individual approach to the treatment of bronchial asthma with beta-sympathomimetic drugs.

Adrenergic beta-Antagonists↗
PubMed1988

Fenoterol treatment and desensitization of beta-adrenoceptors in rabbit foetal lung.

The foetal lung responds to beta-receptor agonists with a release of surfactant from alveolar cells. The aim of the present study was to investigate whether the administration of the betamimetic fenoterol could influence the desensitization - associated decrease of beta-adrenoreceptors in the rabbit foetal lung. With experiments on pregnant rabbits, this hypothesis was put to the test and found to be true. At a gestational age of 27-28 days, does were infused 7.5-10.0 mg of fenoterol or given Ringer's solution. The does and foetuses were sacrificed at 12 hours from the start of the infusion, and the number and affinity of beta-adrenergic receptors in lung tissues were determined by a direct binding technique using 3H-dihydroprenolol. These studies show that fenoterol can induce desensitization of beta-receptors in the foetal lung but not in the doe. Thus, it is concluded that desensitization of foetal pulmonary adrenoreceptors may result in diminished lung function after long-term treatment with beta-2 sympathicomimetics.

Animals↗
PubMed1988

Prolactin release during nursing in early puerperium.

The changes induced in prolactin levels during the first 6 days following delivery were studied. Blood samples for prolactin assay were taken from 9 women at 5-min intervals during breast feeding. The levels of lactation were followed via the amounts of milk produced during suckling. The highest prolactin levels were observed on days 2-4 following delivery. There appeared to be some correlation between the basal and breast-feeding-induced prolactin levels and the level of lactation. A relatively low basal level and a moderate feeding-induced response are early indicators of delayed and less productive lactation. In unfavourable cases the feeding-induced prolactin increases gradually disappeared and lactation stopped. The correlation between the prolactin level and the quantity of milk formed is not a close one, but the observed tendencies agree with the role of prolactin. From day 5 on, the prolactin demands of the breasts are lower.

Female↗
PubMed1987

The effect of E. coli infection on the prostaglandin synthesizing capacity of postobstructive rat kidney.

The PGE2, PGI2, PGF2 alpha and TxA2 synthesizing activities were studied in an isolated microsomal fraction of rat kidney after temporary, unilateral ureter obstruction and E. coli infection. In the early phase of regeneration the synthesis of vasodilatory PGI2 was increased, whereas that of vasoconstrictory PGF2 alpha was decreased. An increased PGE2 synthesizing activity was observed when renal obstruction was associated with infection. The role of these changes in regenerating the haemodynamics and function of postobstructive kidney is discussed.

Animals↗
PubMed1986

Binding properties of beta-adrenergic receptors in early human fetal lung.

The characteristics of beta-adrenergic receptors in human fetal lung were examined using the beta-adrenoceptor antagonist 3H-dihydroalprenolol /DHA/. Steady-state binding was reached by 15 min at 25 degrees C, and the association and dissociation rate constants were 0.0422 nM-1 min-1 and 0.0874 min-1, respectively. From saturation experiments, Bmax of 82.0 +/- 38 fmol/mg protein and KD = 1.85 +/- 0.92 nM were calculated. Inhibition of 3H-DHA binding by beta-1 /metoprolol/ and beta-2 /zinterol, IPS-339, fenoterol/ selective drugs resulted in biphasic displacement curves with slope factors less than 1.0. Analysis of these curves revealed a beta-1: beta-2 ratio of 40:60 in human fetal lung. The presence of 3H-DHA binding sites in early human lung may have a developmental importance which is not yet understood.

Adrenergic beta-Agonists↗
PubMed1986

Affinity of tocolytic agents on human placental and myometrial beta-adrenergic receptors.

The beta-adrenoreceptor antagonist [3H]-dihydroalprenolol (DHA) has been used to label adrenoreceptors in membranes from human pregnant myometrium and placenta. Six tocolytic drugs were tested for their ability to bind to the beta-adrenergic receptor of placental and myometrial membranes. Tocolytic agents competed with [3H]-DHA binding in the following order of potency: clenbuterol greater than fenoterol greater than ritodrine greater than isoxsuprine greater than orciprenaline greater than terbutaline. All drugs competed for [3H]-DHA binding sites with HILL coefficients greater than unity indicating heterogeneity of binding. In general, binding of beta-adrenoreceptor agonists was weaker in myometrium than in placenta homogenates. According to our results it is very likely that the placenta may play an important role in the pharmacological mechanism of tocolytic agents in inhibitory of premature labor.

Adrenergic beta-Agonists↗
PubMed1986

Plasma cortisol, prolactin and thyroxine levels related to midazolam anaesthesia.

Changes of plasma cortisol, prolactin and thyroxine levels as a result of surgical stress were examined in 11 patients undergoing abdominal hysterectomy. General anaesthesia was induced with the new benzodiazepine derivative midazolam (0.25 +/- 0.04 mg/kg) and maintained by nitrous oxide in oxygen. Plasma cortisol and thyroxine levels slightly decreased at the induction of anaesthesia and the beginning of surgery, while the prolactin level increased. By the end of surgery the cortisol and prolactin concentrations increased significantly, although the thyroxine level had barely changed. The highest hormone values were observed a few hours after the operation, but on the next morning hormone levels approached the normal range. On the basis of these results anaesthesia induction with midazolam can be said to have favourably affected the unwanted degree of hormonal changes related to surgery.

Adult↗
PubMed1985

The mechanism of the inhibitory effect of progesterone on lymphocyte cytotoxicity: I. Progesterone-treated lymphocytes release a substance inhibiting cytotoxicity and prostaglandin synthesis.

Progesterone-treated lymphocytes (generator lymphocytes) of healthy pregnant women release a nondialyzable factor that inhibits both cytotoxic activity and prostaglandin F2 alpha synthesis of test lymphocytes. Production of this factor is blocked by protein synthesis inhibitors (cycloheximide and actinomycin D). Sodium dodecylsulfate polyacrylamide electrophoresis of the partially purified material revealed a main 34,000 MW protein band. Progesterone-treated lymphocytes of pregnant women showing clinical symptoms of threatened preterm delivery (risk group) failed to release this substance.

Cells, Cultured↗
PubMed1985

The mechanism of the inhibitory effect of progesterone on lymphocyte cytotoxicity: II. Relationship between cytotoxicity and the cyclooxygenase pathway of arachidonic acid metabolism.

In the previous paper we have demonstrated that progesterone-treated lymphocytes of healthy pregnant women produce a 34,000 MW protein that inhibits cytotoxic activity and prostaglandin F2 alpha synthesis. Since recently it has been shown that certain leukotrienes have a stimulatory effect on natural killer activity, in this study an attempt was made to determine whether there is a relationship between cytotoxicity and PGF2 alpha synthesis or if alterations in the values of these parameters are independent. Arachidonic acid increased cytotoxic activity of healthy pregnant women's peripheral blood mononuclear cells (PBMC) in a concentration-dependent manner. Exogenous arachidonic acid was able to counteract the blocking effect of the above-mentioned protein produced by progesterone-treated lymphocytes. To determine whether the products of the cyclooxygenase or the lipoxygenase pathway of arachidonic acid metabolism are responsible for increased cytotoxicity, both enzyme systems were blocked separately. Both indomethacin and the lipoxygenase inhibitor BW 755C reduced cytotoxicity in a dose-dependent fashion. However, the lipoxygenase inhibitor prevented prostaglandin synthesis to the same extent, or even more than indomethacin, in all concentrations used; so, its blocking effect cannot be considered as supportive evidence for the role of leukotrienes in cytotoxicity. On the other hand, lipopolysaccharide, with a selective stimulatory effect on prostaglandin synthesis, increased cytotoxicity. Lipopolysaccharide had no effect on progesterone-pretreated PBMC. The above data allow the assumption that besides leukotrienes, cyclooxygenase products may also increase cytotoxicity.

4,5-Dihydro-1-(3-(trifluoromethyl)phenyl)-1H-pyraz↗
PubMed1985

The effects of benzodiazepines as anaesthesia inducing agents on plasma cortisol level in elective hysterectomy.

The effects of anaesthesia inducing benzodiazepines (diazepam, flunitrazepam, midazolam) on serum cortisol level, blood pressure and pulse rate were examined in patients undergoing elective hysterectomy. Diurnal variation of serum cortisol was established two days before operation. Either form of benzodiazepine provided good suppression of the cortisol response to stress during anaesthesia and surgery. The endocrine response to surgical stress was more pronounced at end of the operation in all three groups. Considering the relative changes of cortisol compared to the pre-operative values the smallest differences were seen in the group receiving midazolam. At 6 p.m. on the day of operation the cortisol level decreased in the flunitrazepam and midazolam groups. Especially in the patients who received midazolam at 6 a.m. on the following day the values did not differ from those observed in the control group. On the basis of these examinations it would appear that to prevent adverse stress-induced effects there is a slight advantage in using midazolam for induction of anaesthesia.

Adjuvants, Anesthesia↗
PubMed1985

Characterization of beta-adrenergic receptors in human myometrium and placenta.

The binding characteristics of the beta-adrenergic ligand [3H]-dihydroalprenolol (DHA) were determined in particulate membranes of early and term human placenta and myometrium. Human placenta is rich in beta adrenergic receptors and the binding capacity increases with increasing gestation. There was no difference in receptor density in human myometrium comparing the first trimester and term. Binding of DHA to human myometrial beta-adrenergic receptors provides a tool for the analysis of beta-adrenergic agents as potentially useful tocolytic agents.

Binding, Competitive↗
PubMed1985

Comparative study of intravenous anaesthetic techniques administered during short-term gynecological operations.

The effects of nine intravenous anaesthetic techniques on serum cortisol level and circulatory parameters were studied in healthy patients undergoing termination of pregnancy. Considering the increased pre-operation values and those of the pregnant control group as well as diurnal variations, it was found that the serum cortisol value changed during and after the procedure depending on the type of anaesthesia used. This might mean that the optimal type of anaesthesia for interruption could be designed by measuring the serum cortisol level, assuming that this parameter was one of the indicators of stress. The rating the different types of anaesthetics, the circulatory parameters were also considered. According to these criteria the best results were observed using methohexital in combination with fentanyl or diazepam.

Abortion, Legal↗