Suppressed Production of Transforming Growth Factor-β2 mRNA in Endometrium of Women with Polycystic Ovary Syndrome

Production of transforming growth factor-₂ mRNA in the endometrium of women with polycystic ovary syndrome decreased compared to normal and this decrease directly depends on the duration of anovulatory period (from 3 weeks to 4 months). Low production of transforming growth factor-₂ mRNA probably contributes to the development of endometrial hyperplasia in women with polycystic ovary syndrome.     

Exposure to the n-3 polyunsaturated fatty acid docosahexaenoic acid impairs α1-adrenoceptor-mediated contractile responses and inositol phosphate formation in rat cardiomyocytes

The beneficial effects of n-3 polyunsaturated fatty acids of fish oil in the prevention of fatal arrhythmias in myocardial ischemia were suggested to be at least in part mediated by a modulation of dihydropyridine-sensitive L-type calcium channels. As cardiac ₁-adrenoceptor stimulation has been suggested to have no significant effect on L-type calcium channels, the aim of this study using cultured neonatal rat cardiomyocytes was to investigate whether chronic n-3 polyunsaturated fatty acid exposure may have an influence on ₁-adrenoceptor-induced positive inotropic effects and induction of arrhythmias. Pretreatment of the rat cardiomyocytes for 3 days in the presence of the n-3 polyunsaturated fish oil-derived fatty acid docosahexaenoic acid (60 mol/l) markedly decreased ₁-adrenoceptor-stimulated increase in contraction velocity and induction of arrhythmias. The increase in contraction velocity of the cardiomyocytes induced by the -adrenoceptor agonist isoprenaline was also markedly reduced by the n-3 fatty acid pretreatment. Basal contractile amplitude and spontaneous beating frequency of the cardiomyocytes were not significantly altered by the docosahexaenoic acid exposure. The pretreatment of the rat cardiomyocytes for 3 days in the presence of docosahexaenoic acid (60 mol/l) decreased ₁-adrenoceptor-stimulated formation of the calcium-mobilizing second messenger IP₃ and its metabolites IP₂ and IP₁ by 55%. The depression of IP₃ formation by docosahexaenoic acid treatment was not mediated by a decreased uptake of myo-inositol into the cardiomyocytes nor by a decreased synthesis of phosphatidylinositol bisphosphate (PIP₂), the substrate of phospholipase C. The level of glycerol-3-phosphate, an important substrate of the phosphoinositide cycle, was unaltered by the docosahexaenoic acid pretreatment. Receptor binding studies revealed that the dissociation constant and maximal binding capacity of the ₁-adrenoceptor antagonist (³H)prazosin was unchanged by the n-3 polyunsaturated fatty acid exposure. -Adrenoceptor-and forskolin-stimulated adenylyl cyclase activities were not diminished by the docosahexaenoic acid pretreatment. Chronic exposure of the cardiomyocytes to the n-6 polyunsaturated fatty acid arachidonic acid (60 mol/l) did neither significantly alter ₁-adrenoceptor-induced inositol phosphate formation nor ₁-adrenoceptor-stimulated increase in contraction velocity. The results presented show that chronic n-3 polyunsaturated fatty acid pretreatment of rat cardiomyocytes leads to a marked impairment of ₁-adrenoceptor-induced positive inotropic effects and induction of arrhythmias concomitant with a n-3 fatty acid-induced decrease in IP₃ formation. This derangement of the phosphonositide pathway by chronic n-3 fatty acid exposure may, thus, contribute to the beneficial effects of fish oil-derived fatty acids in the prevention of fatal arrhythmias in myocardial ischemia.     

Evaluation of P2-purinoceptor antagonists at two relaxation-mediating P2-purinoceptors in guinea-pig taenia coli

The guinea-pig taenia coli possesses two relaxation-mediating receptors for nucleotides: a prototypic P_2Y-purinoceptor, which is activated by adenosine 5-O-(2-thiodiphosphate) (ADPßS), and a separate receptor for ,-methylene ATP (,-MeATP). Effects of several as yet incompletely characterized P₂-purinoceptor antagonists at these receptors were examined.The concentration-relaxation curve of ADPßS was shifted to the right by reactive blue 2, suramin, 8-(3,5-dinitro-phenylenecarbonylimino)-1,3,5-naphthalenetrisulphonic acid (XAMR0721; at 1000 M only), pyridoxalphosphate-6-azophenyl-2,5-disulphonic acid (iso-PPADS), pyridoxal 5-phosphate, trypan blue and Evans blue (at 320 M only). Schild plots for the antagonism of reactive blue 2, suramin, iso-PPADS and pyridoxal 5-phosphate against ADPßS had slopes <1. The concentration-relaxation curve of ,-MeATP was shifted to the right by reactive blue 2, suramin, XAMR0721, iso-PPADS, pyridoxal 5-phosphate and trypan blue but not by Evans blue (320 M). Schild plots for the antagonism of suramin, XAMR0721 and iso-PPADS against ,-MeATP had slopes >1. Only XAMR0721 differed clearly in potency against the two nucleotides: it was considerably more potent against ,-MeATP than against ADPßS. 2-Methylthio ATP (MeSATP; 1 M) and ATP (100 M) were degraded by pieces of taenia coli. All antagonists except trypan blue attenuated the degradation of either or one of the two nucleotides.The selective effect of XAMR0721 against ,-MeATP confirms the existence of two relaxation-mediating P₂-purinoceptors in guinea-pig taenia coli. Comparison of the apparent affinities of the antagonists for the two taenia coli receptors with affinities for the P_2X-purinoceptor of the rat vas deferens shows that reactive blue 2, suramin, iso-PPADS, pyridoxal 5-phosphate and trypan blue have little selectivity for any of the three receptors. XAMR0721, which has been shown to possess relatively high affinity for the P_2Y-purinoceptor in turkey erythrocytes, was very weak at the P_2Y-receptor of the taenia, thus supporting the existence of pharmacologic P_2Y-receptor subtypes. Evans blue, with little effect in the taenia coli but a marked effect in the rat vas deferens, is the most selective P_2X-(versus P_2Y-) purinoceptor antagonist presently known, although its effect on the degradation of nucleotides must be kept in mind.     

Effects of pretreatment with spironolactone on pharmacokinetics of 4‴-methyldigoxin in man

Summary Pharmacokinetics of ³H-4-methyldigoxin (md) were studied in three paired experiments with and without pretreatment with spironolactone (7 mg/kg/day for 7 days) and in one additional test person after pretreatment only. The results were compared with controls after oral (n=6) and intravenous (n=6) administration of md. In addition the biliary excretion of md and its metabolites was investigated in biliary fistula patients with and without pretreatment with spironolactone.After pretreatment of normal persons maximum plasma levels of tritium were approximately 35% lower and they were reached on average 60 min after oral administration as compared with approximately 15 min without pretreatment. Already 12 hrs after oral administration the plasma concentrations, with and without pretreatment, no longer differed and the biological half lives of radioactivity in plasma were equal.With or without pretreatment, the cumulative excretion of tritium in urine and faeces was nearly identical in the paired experiments within 7 days. It was in the range of the controls which eliminated 55.2±2.8 and 28.6±5.7% of the dose in urine and faeces, respectively, after oral, and 62.2±2.1 and 28.9±5.2%, respectively, after i.v. administration. Accordingly after pretreatment the radioactivity excreted in bile within 48 hrs (14.9% of the dose) did not differ from controls. Examination of the composition of labelled compounds excreted in urine and bile revealed no significant alterations in the metabolic degradation of md under the influence of spironolactone. Thus the profound effects of spironolactone upon pharmacokinetics of md previously observed in rats are without any significance for human conditions.Supported by the Deutsche Forschungsgemeinschaft (Ab 28/1).     

Alpha2-adrenoceptor-mediated responses to so-called selective alpha1-adrenoceptor agonists after partial blockade of alpha1-adrenoceptors

Summary In dog saphenous vein — a tissue possessing both postsynaptic ₁- and ₂-adrenoceptors — the effects of two selective ₁-adrenoceptor agonists (phenylephrine and methoxamine) were compared with that of the selective ₂-adrenoceptor agonist, UK-14,304, before and after phenoxybenzamine. Furthermore, the influence exerted by prazosin, yohimbine and verapamil on the effects of these agonists was also studied before and after phenoxybenzamine. In the absence of phenoxybenzamine, prazosin (56 nmol/l) caused a parallel shift of the concentration-response curves of both phenylephrine and methoxamine to the right (by 0.94 and 1.1 log units, respectively) and had no effect on the concentration-response curve of UK-14,304, while 20 nmol/l yohimbine caused a marked parallel shift of the concentration-response curve of UK-14,304 to the right (by 1.18 log units) and caused only minor displacements of those of phenylephrine and methoxamine (by 0.2 and 0.33 log units, respectively). After exposure of the strips to 30 nmol/l phenoxybenzamine, prazosin (56 nmol/l) caused small shifts of the concentration-response curves of both phenylephrine (by 0.36 log units) and methoxamine (by 0.31 log units) and did not change that of UK-14,304, while yohimbine (20 nmol/l) caused pronounced parallel shifts of the concentration-response curves (to the right) of all the agonists: phenylephrine (by 1.0 log units), methoxamine (by 0.93 log units) and UK-14,304 (by 1.28 tog units). When UK-14,304 was added to the bath during a sub-maximal contraction to phenylephrine it caused a further contraction almost up to the maximum; if this procedure was repeated after phenoxybenzamine (30 nmol/1), there was no further contraction to UK-14,304.In the absence of phenoxybenzamine, verapamil (5 mol/l) caused a parallel shift of the concentration-response curve of phenylephrine (or methoxamine) to the right and a non-parallel shift (with marked depression of the maximal effect) of that of UK-14,304. However, after phenoxybenzamine (30 nmol/l), the same concentration of verapamil caused non-parallel shifts of the concentration-response curves of the three agonists to the right with about equal depression of the maximal effects. We conclude that, after removal of ₁-adrenoceptor reserve by phenoxybenzamine, the responses to selective ₁-adrenoceptor agonists are predominantly ₂-adrenoceptor-mediated. This may explain why under these conditions, the selective ₁-and ₂-adrenoceptor agonists are equally antagonized by calcium entry blockers.This work was supported by a grant from the University of Porto (Subsidio para acção de investigação no. 36/85) Send offprint requests to S. Guimarães at the above address     

99mTc‐labeled oligomeric nanoparticles as potential agents for folate receptor‐positive tumor targeting

One type of biocompatible nanoparticles functionalized with folate and ^99mTc was successfully synthesized. Maleimide‐folic acid (Mal‐FA) was selected to covalently conjugate with ‐SH of the nanoparticles ( NPs ) to prepare NPs‐FA for targeting. ^99mTc was selected to conjugate with ‐NH₂ and ‐SH groups of cysteine residues on the surface of NPs to prepare NPs‐FA‐ ^99m Tc for radioactive counting. The ability to target folate receptors of NPs‐FA‐ ^99m Tc was assessed in uptake studies with folate‐receptor–positive human HepG2 cells. The results showed that the as‐prepared NPs can selectively uptake by folate receptor‐overexpressing HepG2 tumor cells in vitro. The oligomeric hybrid NPs radiolabeled with ^99mTc may develop to be SPECT/CT imaging biomaterials with high selectivity.     

门控断层心室显像评价右室不同部位起搏患者的同步性

Objective To compare the effect of right ventricular outflow tract (RVOT) and right ventricular apex (RVA) pacing on ventricular systolic synchrony using gated blood pool SPECT (GBPS).Methods A total of 50 patients implanted with pacemaker due to high degree or complete atria-ventricular block were enrolled in the study. Twenty-three patients were RVOT paced ( Group A, n = 23) and 27 were RVA paced (Group B, n=27). Twenty-four patients with malignancy, normal echocardiographic findings and no history of cardiac diseases were scheduled for pre-chemotherapy evaluation of cardiac structure and function and were enrolled as control group ( Group C, n = 24). All patients underwent GBPS imaging and the values of phase angle (PS), mean phase of each wall, standard deviation (SD) of mean phase of each wall, lateral-septal motion delay of left ventricle ( LV Sep-Lat Delay), septal-right ventricular (RV) delay of LV ( LV Sep-RV Delay) and LV-RV Delay were acquired. The parameters of ventricular systolic synchrony among the three groups were compared using one-way ANOVA. Results The mean phase of LV lateral wall in Groups A and B were significantly higher than that in Group C: Group A (120.50 ±40.58) ms; Group B (103.23±28.34) ms; Group C (84.63 ±22.38) ms (F=7.72, P ＜0.05). There was no significant difference between Groups A and B ( t = 1.30, P ＞ 0.05 ). The mean phase of RV in Group A was significantly larger than those in Groups B and C: Group A ( 137.05 ± 39.27) ms, Group B ( 100.85 ± 23.79) ms,Group C (59. 13 ±30.52) ms (F=35.55, P＜0.05). PS, SD and LV Sep-Lat Delay in Groups A and B were significantly higher than those in Group C: (85.73 ± 12.00)°vs (89.85 ± 15.61 )°vs (58.95 ±9.87)°, (27.68±10.66) ms vs (26.15 ±13.02) ms vs (15.63 ±8.35) ms, (25.06±34.23) ms vs (2. 62 ± 60. 31 ) ms vs ( - 23.66 ± 31.39) ms, F = 41.54,8.55,6.81, all P ＜ 0.01 ), however, there was no significant difference between Groups A and B ( t = 0. 68, 0.68, 1.30, all P ＞ 0.05 ). LV Sep-RV Delay and LV-RV Delay were significantly different among the three groups ( LV Sep-RV Delay: Group A (57.60 ±56.77) ms, Group B (6.36 ±61.88) ms, Group C ( -41.89 ±35.78) ms; LV-RV Delay:Group A (47.36 ±42.59) ms, Group B ( 3.08 ± 38.81 ) ms Group C ( - 26.50 ± 20.99 ) ms, F = 20. 32,25.38, both P ＜ 0.01 ). Conclusion Both RVA and RVOT pacing increase the segmental phases detected by GBPS, causing inter- and intra- ventricular asynchrony compared with patients without pacemakers.     

Glucocorticoids modulate TGF-beta production by human fetal lung fibroblasts

TGF- is thought to play a central role in pulmonary fibrosis inducing fibroblast differentiation and extracellular matrix synthesis. In human lung fibroblasts, it is still unclear how various TGF- isoforms affect TGF- production and whether glucocorticoids, commonly used agents to treat fibrotic lung disease, modulate these processes. To this end, human fetal lung fibroblasts (HFLF) were cultured with various concentrations of glucocorticoids (budesonide, dexamethasone or hydrocortisone) with and without TGF-1, -2, or -3. Post-culture media were collected for ELISA assays of TGF-1, -2, and -3 . TGF- mRNA was assessed by real time RT-PCR. Smad 2, 3, and 4 and AP-1 complex (c-fos and c-Jun) cellular localization were evaluated by immunostaining. TFG-2 and -3 stimulated TGF-1 production significantly (p < 0.01 relative to control). TGF-1 stimulated TGF-2 production (p < 0.01 relative to control). TGF-3 was undetectable. Glucocorticoids significantly inhibited TGF-1 and TGF-2 production and reduced expression of the up-regulated TGF-1 and TGF-2 mRNA induced by exogenous TGF-1, -2, or -3 (p < 0.01 for each) but had no effect on Smads. Although c-jun-related nuclear staining was not intensified in TGF--stimulated cells, it was reduced by glucocorticoids. Thus, TGF- isoforms may stimulate production of various TGF- isoforms in the lung. Glucocorticoids then may block TGF- production by modulating mRNA levels and c-Jun.     

Expression and localization of fukutin, POMGnT1, and POMT1 in the central nervous system: consideration for functions of fukutin

Fukuyama-type congenital muscular dystrophy (FCMD), muscle-eye-brain disease (MEB), and Walker–Warburg syndrome (WWS) are congenital muscular dystrophies associated with central nervous system (CNS) lesions, represented by cobblestone lissencephaly and eye anomalies. The glia limitans, formed by astrocytic endfeet and covered with the basement membrane, is disrupted in fetal cases of these diseases. A gene responsible for FCMD is fukutin and that for MEB is protein O-linked mannose 1,2-N-acetylglucosaminyltransferase (POMGnT1). Mutations in protein-O-mannosyltransferase 1 (POMT1) have been found in some WWS cases. POMGnT1 and POMT1 are involved in glycosylation of -dystroglycan, which is one of the components of dystrophin–glycoprotein complex, linking dystrophin and extracellular matrix proteins at the basement membrane. Fukutin seems to have similar functions to those of POMGnT1 and POMT1, but its functions still remain to be clarified. In situ hybridization reveals that fukutin, POMGnT1, and POMT1 are expressed especially in astrocytes. Decrease of glycosylated -dystroglycan has been reported in the skeletal muscle of FCMD, MEB, and WWS. Moreover, decrease of fukutin and glycosylated -dystroglycan is observed in the brain of FCMD cases. Because astrocytes are involved in basement membrane formation at the glia limitans, fukutin, POMGnT1, and POMT1 are considered to relate to the pathogenesis of CNS lesions, and fukutin may be related to glycosylation of -dystroglycan. Fukutin, POMGnT1, and POMT1 are expressed in immature neurons, suggesting they are also involved in neuronal migration itself. POMGnT1 and POMT1 are expressed in many mature neurons, but fukutin is positive in a few mature neurons. FCMD is a rather mild disease among FCMD, MEB, and WWS, and POMGnT1 and POMT1 seems to have more critical roles compared to fukutin in mature neurons.