Urinary bisphenol A levels in Turkish girls with premature thelarche.

There is a growing concern over the timing of pubertal breast development and its possible association with exposure to endocrine disrupting chemicals (EDCs), such as bisphenol A (BPA). BPA is abundantly used to harden plastics. The aim of this study was to investigate the relation between premature thelarche (PT) and BPA by comparing the urinary BPA levels of PT girls with those of healthy subjects. Twenty-five newly diagnosed nonobese PT subjects (aged 4-8 years) who were admitted to the Pediatric Endocrinology Department at Akdeniz University were recruited. The control group composed of 25 age-matched girls without PT and other endocrine disorders. Urinary BPA levels were measured by high pressure liquid chromatography. The median urinary concentrations of BPA were found to be significantly higher in the PT group compared to the healthy control group (3.2 vs. 1.62 µg/g creatinine, p < 0.05). We observed a weak positive correlation between uterus volume and urinary BPA levels. There was a weak correlation between estradiol and urinary BPA levels ( r = 0.166; p = 0.37); and luteinizing hormone and urinary BPA levels ( r = 0.291; p = 0.08) of PT girls. Our results suggest that exposure to BPA might be one of the underlying factors of early breast development in prepubertal girls and EDCs may be considered as one of the etiological factors in the development of PT.

Urinary zearalenone levels in girls with premature thelarche and idiopathic central precocious puberty.

AIM: Recently, it was reported that the development of breast tissue and secondary sex characteristics in girls occurred at much younger age and the incidences of premature thelarce (PT) and central idiopathic precocious puberty (ICPP) are increasing. In this context, we wanted to evaluate the mycoestrogen exposure as triggering factor for premature sexual development. METHODS: The girls living in Mediterranean region of Turkey were divided in to three groups: control (N.=25; mean age: 6.45 ± 1), PT (N.=28; mean age: 6.86 ± 0.95) and ICPP (N.=25; mean age: 6.97 ± 0.87). Urinary ZEN levels were measured by using ELISA technique and were normalized by urinary creatinine levels. Body Mass Index (BMI) was evaluated and sex hormone levels were also measured. RESULTS: We found that urinary ZEN was detectable in ~81% of all samples and observed an increase of ~2-fold in PT and a significant increase ~2.8-fold in ICPP group vs. control. We did not find any significant correlations between urinary ZEN levels and BMI and sex hormones in any of the groups. CONCLUSION: To our knowledge, this is the first study evaluating urinary ZEN levels in PT and ICPP Turkish patients. We can postulate that ZEN exposure can contribute to the etiology of PT and PP; however further studies on large number of subjects are needed to confirm the present data.

The role of nitric oxide in mediating nonadrenergic, noncholinergic relaxation in rat pulmonary artery.

Experiments were undertaken to investigate the existence of inhibitory nonadrenergic, noncholinergic (i-NANC) nerve activity by using in vitro functional and immunohistochemical techniques in rat main pulmonary arterial rings. Vessels precontracted with phenylephrine (3 microM) relaxed in response to electrical field stimulation (EFS) (50 V, 0.2 ms, 0.1-10 Hz for 5 s) in the presence of atropine (1 microM) and guanethidine (1 microM). Tetrodotoxin (0.3 microM) abolished this response, indicating that it is neuronal in origin. l-NAME (30 microM), methylene blue (10 microM), and removal of endothelium significantly reduced the EFS-induced relaxations. The inhibitory action of l-NAME was completely reversed by l-arginine (1 mM) but not by d-arginine (1 mM). Moreover l-arginine alone potentiated the magnitude of the relaxations elicited by EFS. On the other hand, immunohistochemical work clearly demonstrated the existence of neuronal nitric oxide synthase in the pulmonary artery vessel wall. All these results are consistent with the suggestion that nitric oxide is the likely mediator of this vasodilatation. However, the incomplete blockade of the responses by l-NAME gives evidence of an additional inhibitory NANC neurotransmitter(s) mediating the residual relaxation, which requires further experiments to clarify its nature.

L-NAME enhances responses to atrial natriuretic peptide in the pulmonary vascular bed of the cat.

This study investigated the hypothesis that atrial natriuretic peptide (ANP) responses are mediated by particulate guanylate cyclase in the pulmonary vascular bed of the cat. When tone in the pulmonary vascular bed was raised to a high steady level with the thromboxane mimic U-46619, injections of ANP caused dose-related decreases in lobar arterial pressure. After administration of HS-142-1, an ANP-A- and ANP-B-receptor antagonist, vasodilator responses to ANP were reduced. The nitric oxide (NO) synthase inhibitor N(omega)-nitro-L-arginine methyl ester (L-NAME) enhanced ANP vasodilator responses, suggesting that inhibition of NO modulates ANP responses. L-NAME administration with constant 8-bromo-cGMP infusion attenuated the increased vasodilator response to ANP, suggesting that supersensitivity to ANP occurs upstream to activation of a cGMP-dependent protein kinase. In pulmonary arterial rings, ANP produced concentration-related vasorelaxant responses with and without endothelium. Methylene blue, L-NAME, or N(omega)-monomethyl-L-arginine did not alter ANP vasorelaxant responses. These data show that ANP supersensitivity observed in the intact pulmonary vascular bed is not seen in isolated pulmonary arterial segments, suggesting that it may only occur in resistance vessel elements. These results suggest that ANP responses occur through activation of ANP-A and/or -B receptors in an endothelium-independent manner and are modulated by NO in resistance vessel elements in the pulmonary vascular bed of the cat.

Association of nitric oxide production and apoptosis in a model of experimental nephropathy.

BACKGROUND: In recent studies increased amounts of nitric oxide (NO) and apoptosis have been implicated in various pathological conditions in the kidney. We have studied the role of NO and its association with apoptosis in an experimental model of nephrotic syndrome induced by a single injection of adriamycin (ADR). METHODS: The alteration in the NO pathway was assessed by measuring nitrite levels in serum/urine and by evaluating the changes in vascular reactivity of the isolated perfused rat kidney (IPRK) system. Rats were stratified into control groups and ADR-induced nephropathy groups. These two groups were then divided into: group 1, animals receiving saline; and group 2, animals receiving aminoguanidine (AG) which is a specific inhibitor of inducible-NO synthase. On day 21, rats were sacrificed after obtaining material for biochemical analysis. RESULTS: Histopathological examination of the kidneys of rats treated with ADR revealed focal areas of mesangial proliferation and mild tubulointerstitial inflammation. They also had significantly higher levels of proteinuria compared with control and treatment groups (P < 0.05). Urine nitrite levels were significantly increased in the ADR-nephropathy group (P < 0.05). In the IPRK phenylephrine and acetylcholine related responses were significantly impaired in the ADR-nephropathy group. Apoptosis was not detected in controls. However, in the ADR-nephropathy group, numerous apoptotic cells were identified in the tubulointerstitial areas. Double staining revealed numerous interstitial apoptotic cells to stain for ED1, a marker for monocytes/macrophages. Treatment with AG prevented the impairment of renal vascular bed responses and reduced both urine nitrite levels and apoptosis to control levels. CONCLUSION: We suggest that interactions between NO and apoptosis are important in the pathogenesis of the ADR-induced nephrosis.

Simultaneous determination of acetaminophen, acetylsalicylic acid and ascorbic acid in tablet form using HPLC.

The purpose of the present study was to develop a simple and accurate HPLC method to measure the amount of each agent in a multidrug pharmaceutical formulation. Three drugs, acetaminophen, acetylsalicylic acid and ascorbic acid, were analyzed simultaneously. A commercial pharmaceutical effervescent tablet was examined and the amount of each of these agents successfully determined. The present method appears to be more convenient than the current procedures described in American and British Pharmacopoeias in which each drug is assayed separately.

Novel catheterization technique for the in vivo measurement of pulmonary vascular responses in rats.

A novel cardiac catheterization technique was devised to investigate the pulmonary arterial pressure-blood flow relationship in intact spontaneously breathing rats (ISBR) under physiological conditions with constant left atrial pressure and controlled blood flow within the normal range. Observations using this new technique in vivo were contrasted with data derived with isolated perfused rat lungs in vitro. Unlike results in in vitro isolated perfused rat lungs, the pressure-flow curves in vivo were curvilinear, with pulmonary artery pressure increasing more rapidly at low pulmonary blood flows of 4-8 ml/min and less rapidly at higher flow rates. Pressure-flow curves were reproducible and were not altered by 1-1.5 h of arrested perfusion, cyclooxygenase blockade, or perfusion with aortic or mixed venous blood. In contrast to results in in vitro isolated perfused rat lungs, NG-nitro-L-arginine methyl ester (L-NAME) increased pulmonary arterial pressure at all but the lowest flow rates with a slight effect on the curvilinear pressure-flow relationship. L-NAME reversed pulmonary vasodilator responses to acetylcholine and bradykinin and enhanced the pulmonary vasodilator response to nitroglycerin. The present data suggest that actively induced pulmonary hypertension is under greater control by endothelium-derived relaxing factor (EDRF). Unlike previous results in in vitro perfused rat lungs, results in ISBR demonstrate that the pulmonary vasodilator response to adrenomedullin-(13-52) is not mediated by calcitonin gene-related peptide receptors, which are not coupled to the release of EDRF. These results indicate that this novel technique may provide a useful model for the study of the pulmonary circulation in the intact chest rat.

Analysis of responses to adrenomedullin-(13-52) in the pulmonary vascular bed of rats.

The effects of human adrenomedullin-(13-52) [hADM-(13-52)] were investigated in the rat pulmonary vascular bed and in isolated rings from the rat pulmonary artery (PA). Under conditions of controlled blood flow and constant left atrial pressure when tone was increased with U-46619, injection of hADM-(13-52) produced dose-related decreases in lobar arterial pressure. Pulmonary vasodilator responses in the intact rat and vasorelaxant responses to hADM-(13-52) in rat PA rings were inhibited by NG-nitro-L-arginine methyl ester (L-NAME) and L-N5-(1-iminoethyl)-ornithine hydrochloride (L-NIO). Vasorelaxant responses to hADM-(13-52) were also inhibited by methylene blue, endothelium removal, hADM-(26-52), and iberiotoxin, whereas meclofenamate, calcitonin gene-related peptide-(8-37) [CGRP-(8-37)], glibenclamide, and apamin were without effect. Because vasorelaxant responses to NS-1619, a large-conductance Ca(2+)-activated K+ channel agonist, were not altered by L-NAME and vasorelaxant responses to acetylcholine and CGRP were not altered by hADM-(26-52), the present data suggest that ADM-(13-52) acts on a receptor in the pulmonary vascular bed that is coupled to endothelial nitric oxide release. These data suggest that this nitric oxide release may lead to guanosine 3',5'-cyclic monophosphate-dependent K+ channel activation, which produces a pulmonary vasorelaxant response through hyperpolarization of vascular smooth muscle cells. The present data suggest that ADM-(13-52) modulates receptor-mediated, but not voltage-dependent, pulmonary vascular contraction by influencing Ca2+ influx. These results suggest that the ADM fragment, hADM-(13-52), acts as an endothelium-dependent vasodilator agent in the pulmonary vascular bed of the rat.

Nociceptin: an endogenous agonist for central opioid like1 (ORL1) receptors possesses systemic vasorelaxant properties.

The purpose of the present study was to investigate the effects of nociceptin on peripheral arterial rings from the cat. When feline renal, mesenteric, carotid and femoral rings with intact endothelium were precontracted with phenylephrine (100 nanomolar), nociceptin (3 x 10(-11)-3 x 10(-6) M) decreased tension in a concentration-dependent manner. The present data suggest nociceptin possesses biologic activity outside the CNS and may contribute to the regulation of systemic blood pressure and regional blood flow.

Adrenomedullin dilates rat pulmonary artery rings during hypoxia: role of nitric oxide and vasodilator prostaglandins.

Hypoxia decreases vasorelaxation and leads to pulmonary arterial hypertension. A newly identified 52 amino-acid peptide adrenomedullin (ADM) exerts vasodilator effect in intact animals under normoxic condition. We studied the effect of human ADM on rat pulmonary arterial and aortic rings under normoxic and hypoxic conditions. During normoxia, ADM caused a concentration-dependent relaxation of precontracted aortic and pulmonary arterial rings; the relaxation was much more pronounced in pulmonary arterial rings and was abolished by the nitric oxide (NO) synthesis inhibitor N omega-nitro-L-arginine methyl ester (L-NAME) and by deendothelialization. A fragment of ADM, ADM13-52, caused a degree of relaxation similar to that induced by ADM in pulmonary arterial rings, but not in the aortic rings, and the relaxation of pulmonary artery caused by ADM13-52 was not affected by the cyclooxygenase inhibitor indomethacin but was abolished by L-NAME and by deendothelialization. During hypoxia, ADM13-52 failed to relax pulmonary arterial rings, whereas ADM caused modest relaxation of pulmonary arterial rings (one third of the relaxation during normoxia), which was abolished by pretreatment with indomethacin. Our results indicate that the vasorelaxant effect of ADM is more pronounced in pulmonary artery than in the aorta; ADM has more potent vasodilator effect than ADM13-52 during hypoxia; ADM relaxes hypoxic pulmonary artery through an indomethacin-sensitive pathway; amino acids 1-12 in ADM must be present for relaxation of chronic hypoxic pulmonary arterial rings; and last, the presence of endothelium is necessary for the expression of ADM-mediated relaxation.

Reactive oxygen species-induced impairment of endothelium-dependent relaxation in rat aortic rings: protection by L-arginine.

The protective effect of L-arginine against reactive oxygen species-induced impairment of endothelium-dependent vasorelaxation was investigated in isolated ring preparations of rat aorta. The aortic rings were subjected to reactive oxygen species generated by the electrolysis of the bathing solution or incubation with H2O2. Endothelium-dependent relaxation in response to acetylcholine of precontracted aortic rings was attenuated when the rings were exposed to reactive oxygen species or H2O2. Incubation prior to electrolysis with either L-arginine, the endogenous precursor of nitric oxide (NO), or sodium nitroprusside, an exogenous donor of NO, protected the aortic rings against the impairment of endothelium-dependent relaxation. However, D-arginine and glycine, amino acids which do not produce NO, also afforded protection in this model. Therefore, not only the increased synthesis of NO but also the oxidation of L-arginine, with concomitant disproportionation of reactive oxygen species, may be responsible for the protective effect against reactive oxygen species-induced loss of the endothelial response to acetylcholine in isolated rat aorta.

Adrenotensin: an adrenomedullin gene product contracts pulmonary blood vessels.

The purpose of the present study was to determine the effects of adrenotensin, a newly described product of the ADM gene, on cat pulmonary arterial (PA) rings. Under resting conditions, adrenotensin increased tension of PA rings in a concentration-dependent manner. Although addition of diphenhydramine, ONO-3708, phentolamine, methysergide, atropine, and meclofenamate did not alter the contractile response to adrenotensin, removal of the endothelial cell layer significantly reduced this response. Moreover, precontraction of PA rings with adrenotensin selectively attenuated the pulmonary vasorelaxant response to ADM but not to other vasodilator substances, including isoproterenol, pinacidil, nifedipine, and adenosine. The present data suggest that adrenotensin acts in an endothelium-dependent manner to contract PA rings. Moreover, the present data suggest that adrenotensin may act in a modulatory manner to influence vasorelaxation in response to ADM, a sister proADM product.

The pulmonary vascular response to propofol in the isolated perfused rat lung.

This study investigated the effect of propofol on the pulmonary vascular bed of the rat. Propofol (5 x 10(-6) to 5 x 10(-4) M) did not alter the basal perfusion pressure in isolated rat lungs perfused at a constant flow (0.03 mL g body wt-1 min-1) with Krebs-Henseleit solution. When perfusion pressure was elevated by raising the K+ concentration to 30 mM (depolarizing Krebs-Henseleit solution), propofol decreased it in a concentration-dependent manner. Indomethacin (3 x 10(-6) M) and NG-nitro-L-arginine methyl ester (10(-4) M) did not affect the response to propofol, which excluded the role of cyclo-oxygenase metabolites and nitric oxide, respectively. The ATP-sensitive K+ (K+ATP) channel blocker glibenclamide (3 x 10(-6) and 10(-5) M) inhibited the vasodilator effect of propofol. When lungs were perfused with Ca(2+)-free depolarizing Krebs-Henseleit solution, 0.1-2.5 mM Ca+2 produced a concentration-dependent pressor response. Propofol (5 x 10(-5) M) attenuated the vasopressor response to Ca2+ significantly. In conclusion, the activation of K+ATP channels is probably the major mechanism of the vasodilator effect of propofol, at clinically relevant concentrations, in the rat lung. The Ca2+ antagonistic property of propofol is evident only at higher concentrations.

3-substituted piperazinomethyl benzoxazolinones. Analgesic and anti-inflammatory compounds inhibiting prostaglandin E2.

Fourty-three new benzoxazolinone derivatives having a piperazinomethyl group at the third position of the ring were synthesized by using appropriate benzoxazolinones and 4-substituted piperazines via a Mannich reaction. The structures of the compounds were elucidated by spectral data and microanalyses. Analgesic activities were evaluated by a modified Koster test. All compounds, except 7, 14, 21, 32, and 41, showed analgesic activity higher than that of acetylsalicylic acid. The compounds were also screened for their anti-inflammatory activity using a carrageenan paw edema test, and those exhibiting high anti-inflammatory activity were investigated for their ability to inhibit prostaglandin E2 induced paw edema. The results of anti-inflammatory testing indicated that most of the compounds were more active than indometacin. Ulcerogenic activities of the compounds were also studied and no gastrointestinal bleeding was observed at the 100 mg/kg dose level.

Synthesis of ethanone and ethanol derivatives of 2-benzoxazolinone; potent analgesic and antiinflammatory compounds inhibiting prostaglandin E2.

Sixteen new ethanone and ethanol derivatives of 6-acyl-2-benzoxazolinones were synthesized and their chemical structures elucidated by IR, 1H-NMR and elemental analysis. Analgesic activities of these compounds were investigated by modified Koster test and constant temperature hot plate test. All the compounds showed higher analgesic activity than aspirin. Therefore the compounds were tested for their antiinflammatory activities using the carrageenan hind-paw edema test. All the compounds that showed high antiinflammatory activity were then further assayed for their ability to inhibit prostaglandin E2 (PGE2) induced paw edema. None of the compounds induced gastric ulceration.

Agmatine: a novel endogenous vasodilator substance.

The purpose of the study was to investigate the effects of agmatine, an endogenous clonidine-displacing substance (CDS), on systemic hemodynamics in the anesthetized rat. Bolus intravenous (i.v.) injections of agmatine decreased systemic arterial pressure (SAP) and systemic vascular resistance in a dose-dependent manner. The development of acute tachyphylaxis to the systemic vasodepressor response to agmatine did not induce cross-tachyphylaxis to the systemic vasodepressor responses to bradykinin, isoproterenol and nitroglycerin. The present data demonstrate agmatine, as a CDS and agonist for imidazoline (I) receptors, possesses marked systemic vasodilator activity in the rat. The present data suggest that activation of I receptors may represent a novel mechanism of vasodilation in vivo.

Adrenotensin: an ADM gene product with the opposite effects of ADM.

The purpose of the present study was to investigate the effects of putative products of the ADM gene, other than ADM including, prodepin, proADM45-92 and proADM153-185 on cat pulmonary arterial (PA) rings with or without precontraction with U46619. Addition of proADM153-185 (3 x 10(-10)-10(-6) M) increased tension in a concentration-dependent manner in cat PA rings without precontraction. When vessels were precontracted with U46619, ADM(3 x 10(-10)-10(-6) M) produced a concentration-dependent vasorelaxant response, whereas proADM153-185 produced a weak concentration-dependent contractile response. Prodepin and proADM45-92 up to 10(-6)M had no activity on PA rings. Since proADM153-185, similar to ADM, would be expected to be released in free form following endopeptidase-induced cleavage, the present data suggest proADM undergoes proteolytic processing to release peptides with divergent vascular effects. Thus, the present data also suggest that proADM153-185 may represent a novel product of the ADM gene and term this putative new substance "adrenotensin".

Effect of changes in swimming area on results of "behavioral despair test".

Our previous observations have revealed that the total time spent in immobility and time to reach complete immobility (latency) vary with the diameter of the cylindric chamber where mice are forced to swim in the behavioral despair test. Therefore, we investigated the effect of changing the test conditions of the original Porsolt test. Mice were forced to swim for 15 min in chambers with 10 cm (original diameter of the Porsolt's forced swimming chamber), 20, 30, and 50 cm diameter in 20 cm deep water. Total time spent in spells of immobility during the observation period from third to sixth (inclusive) minutes and time to reach complete immobility were measured. In addition, a possible correlation between the rotatory locomotor activity of mice during swimming as assessed by the number of tours per minute and effect of antidepressant drugs on it was investigated. Total duration of spells of immobility was shorter and the latency was longer in tests carried out in chambers with 10 cm diameter. Increasing the diameter of the cylinders made it possible to distinguish the antidepressant drugs from caffeine, anticholinergics, and antihistaminics, which gave a false positive response in 10 cm diameter cylinders, but not in cylinders with larger diameters. Increasing the diameter of the chambers to 20 and 30 cm also allowed to study the selective effect of the antidepressants, namely, the rotatory locomotor activity during swimming. The extension of the test period to 15 min increased the reliability of the measurement of the time to reach complete immobility.(ABSTRACT TRUNCATED AT 250 WORDS)