Prediction of placenta accreta spectrum in patients with placenta previa using a clinical, US and MRI combined model: A retrospective study with external validation

PURPOSE

To build and validate a predictive model of placental accreta spectrum (PAS) in patients with placenta previa (PP) combining clinical risk factors (CRF) with US and MRI signs.

METHOD

Our retrospective study included patients with PP from two institutions. All patients underwent US and MRI examinations for suspicion of PAS. CRF consisting of maternal age, cesarean section number, smoking and hypertension were retrieved. US and MRI signs suggestive of PAS were evaluated. Logistic regression analysis was performed to identify CRF and/or US and MRI signs associated with PAS considering histology as the reference standard. A nomogram was created using significant CRF and imaging signs at multivariate analysis, and its diagnostic accuracy was measured using the area under the binomial ROC curve (AUC), and the cut-off point was determined by Youden's J statistic.

RESULTS

A total of 171 patients were enrolled from two institutions. Independent predictors of PAS included in the nomogram were: 1) smoking and number of previous CS among CRF; 2) loss of the retroplacental clear space at US; 3) intraplacental dark bands, focal interruption of the myometrial border and placental bulging at MRI. A PAS-prediction nomogram was built including these parameters and an optimal cut-off of 14.5 points was identified, showing the highest sensitivity (91%) and specificity (88%) with an AUC value of 0.95 (AUC of 0.80 in the external validation cohort).

CONCLUSION

A nomogram-based model combining CRF with US and MRI signs might help to predict PAS in PP patients, with MRI contributing more than US as imaging evaluation.

Collagen-Based Ovule Therapy Reduces Inflammation and Improve Cervical Epithelialization in Patients with Fungal, Viral, and Bacterial Cervico-Vaginitis

Background and Objectives: Vulvovaginal infections pose significant health challenges for women, necessitating effective treatment approaches. This retrospective observational study aimed at investigating the efficacy of collagen-based vaginal ovules therapy, specifically Plurigin Ovules, in restoring cervical epithelialization and reducing inflammation in mycotic, viral, and bacterial cervico-vaginitis. Materials and Methods: A total of 398 women with cervico-vaginitis were included in the study, categorized into three groups: bacterial cervico-vaginitis (Group A), viral cervico-vaginitis (Group B), and fungal cervico-vaginitis (Group C). Participants received vaginal therapy with Plurigin Ovules for three months. Vaginal health parameters were assessed at baseline (T0) and after six months (T1) using various diagnostic tests and analyzed with appropriate statistical tests. Results: Significant improvement in cervico-vaginitis was observed in all three groups. At T1, 87.7% patients of Group A, 66.7% of Group B, and 71.5% of Group C achieved infection resolution (all p < 0.05). Positive colposcopy results decreased across all groups (p < 0.001). Positive vaginal swabs and altered vaginal pH decreased in group A and C (p < 0.001). Positive HPV tests decreased in Group B (p < 0.001). Positive Pap tests and clinical examinations decreased significantly across all groups (p < 0.001). The odds ratios were calculated to reveal the significant associations between these diagnostic outcomes. The therapy was well-tolerated, and no major adverse events were reported. Conclusion: Plurigin Ovules exhibited promising therapeutic outcomes in the three cervico-vaginitis conditions studied. Bacterial cervico-vaginitis showed the most significant improvement, followed by fungal and viral cervico-vaginitis. These findings emphasize the potential of Plurigin Ovules as an effective therapeutic option for cervico-vaginal inflammation and infection, highlighting its role in promoting re-epithelialization and reducing inflammatory processes in the cervix and vagina.

Immersion in water during labor and delivery

Objective: Immersion in water during labor and delivery has been studied as an alternative form of obstetric care. The aim of this study was to evaluate obstetrics and neonatal outcomes of women intending to use immersion in water for labor and delivery. Methods: This was a retrospective observational study conducted at a single center in Italy from January 2004 to January 2016. The clinical records of pregnant women intending to use immersion in water for labor and delivery were collected in a dedicated database and included in the study. Only the women who underwent immersion in water starting from the first stage of labor were included in the study. Inclusion criteria were women with uncomplicated singleton gestations and cephalic presentation at or later than 37 weeks of gestation, and with spontaneous onset of labor. The primary outcome of the study was the percentage of women who had both labor and delivery in water. Results: 389 women met the inclusion criteria and were included in the study. 256 (66%) were nulliparous, and 133 (34%) were multiparous. Out of the 389 women intending to use immersion in water for labor and delivery, 278 (71.5%) had labor and delivery in the water, 31 (8.0%) labor in water and delivery on land, and 80 (20.5%) had the first stage of labor in water, and the second stage and delivery on land. The incidence of perineal lacerations was 61.4%. Conclusion: The vast majority of the women who set out to labor and delivery in water achieve their aim.

Outpatient hysteroscopy

Modern hysteroscopy represents a copernical revolution for the diagnosis and treatment of uterine pathology. Traditionally hysteroscopy was performed in a conventional operation room under general anaesthesia (in-patient hysteroscopy). Recent advances in technology and techniques made hysteroscopy less painful and invasive allowing it to be performed in an ambulatory setting (outpatient hysteroscopy). The so called "see & treat hysteroscopy", has reduced the distinction between diagnostic and operative procedure, thus, introducing the concept of a single procedure in which the operative part is perfectly integrated within the diagnostic work-up. The "digital hysteroscopic clinic" (DHC) on the other hand combines ultrasound with hysteroscopy, ideal for a one stop diagnostic procedure and surgical approach, outlasting laparoscopy with ultrasound, for increased surgical performance in outpatient settings. The aim of this paper is to describe the "state of the art" in an outpatient hysteroscopy setting.

Comparison of bidirectional barbed suture Stratafix and conventional suture with intracorporeal knots in laparoscopic myomectomy by office transvaginal hydrolaparoscopic follow-up: a preliminary report

OBJECTIVES

To compare surgical outcomes of different types of intracorporeal sutures for laparoscopic posterior myomectomy, by a prospective randomized study.

STUDY DESIGN

Prospective randomized study on 47 patients with single posterior intramural myoma (4-7cm in diameter) undergoing laparoscopic myomectomy. The patients enrolled were divided into two groups, one operated using conventional suture in double strand, and the other with bidirectional barbed suture Stratafix. The main outcome measures were suturing time, peri-operative variables, and post-operative adhesions in both groups.

RESULTS

The mean operative time was shorter with the Stratafix™ than with the conventional suture (66.3±8.2 vs. 73±8min; p=0.005). Suturing time was significantly shorter in the Stratafix™ than in the control group (8.8±2.4 vs. 15.5±2.8min; p=0.001). Intraoperative bleeding was significantly less in the Stratafix group (p=0.0012). Conversely, there was no statistically significant difference for postoperative adhesions between the two groups (26.7% vs. 21.4% p=0.5).

CONCLUSIONS

The use of barbed suture may reduce operative time, suturing time, and blood loss. No difference in post operative adhesions was found.

Low-dose estrogen and drospirenone combination: effects on metabolism and endothelial function in postmenopausal women with metabolic syndrome

PURPOSE

Metabolic syndrome and endothelial dysfunction play a relevant role in the cardiovascular risk in post-menopause. The aim of the study was to assess the effects of a low-dose hemihydrate estradiol and drospirenone combination on cardiovascular risk parameters in postmenopausal women with metabolic syndrome.

MATERIALS AND METHODS

Twenty-eight healthy women (group A) and 28 women with metabolic syndrome (group B) were treated with hemihydrate estradiol one mg + drospirenone two mg. At recruitment and after six months, clinical and laboratory parameters of metabolic syndrome were evaluated. Endothelial function was assessed measuring the flow-mediated dilatation of the brachial artery and the intima-media thickness of the common carotid artery.

RESULTS

After six months an overall improvement of metabolism was observed in both groups reaching statistical significance for triglycerides, total cholesterolemia, and systolic pressure in group B. A trend to lower baseline flow-mediated dilatation was also found in group B.

CONCLUSIONS

Drospirenone improves cardiovascular risk factors and does not impair endothelial function in menopausal women with metabolic syndrome.

Plasmid-mediated fluoroquinolone resistance determinants in Escherichia coli from community uncomplicated urinary tract infection in an area of high prevalence of quinolone resistance

In Italy fluoroquinolones (FQs) are extensively prescribed in empirical therapy of uncomplicated urinary tract infection (UTI) despite recommendations in national guidelines and widespread antibiotic resistance in community. To survey the dissemination of plasmid-mediated quinolone resistance in a peak area of FQs consumption, E. coli strains from 154 community and 41 local hospital patients were collected; low level ciprofloxacin resistance qnrA, qnrB, qnrS, and aac(6)'-Ib-cr genes were screened by PCR and patterns of transferable resistances were determined. Clinical ciprofloxacin resistance in hospital doubled community value, while overall rates of FQ resistance genes were similar (31.6% and 27.8%). Prevalence of aac(6')-Ib-cr gene was 11% in outpatients (21%, inpatients) and risk of harbouring this variant was significantly associated with gentamicin resistance; linkage to ceftazidime resistance was significant (P=0.001) and six out of eight strains produced CTX-M-15 and TEM-1 beta lactamases. In transconjugants, the unique pattern ampicillin/kanamycin-gentamicin/ ESBL + was associated with aac(6')-Ib-cr gene presence and with an increase of ciprofloxacin MIC value. Data highlight the need to monitor the resistance risk factors in the local community to provide clinicians with well-grounded guidelines for UTI therapy.

Modulation of AMPA receptor-mediated ion current by pituitary adenylate cyclase-activating polypeptide (PACAP) in CA1 pyramidal neurons from rat hippocampus

Pituitary adenylate cyclase-activating polypeptide (PACAP), a neurotrophic and neuromodulatory peptide, was recently shown to enhance NMDA receptor-mediated currents in the hippocampus (Macdonald, et al. 2005. J Neurosci 25:11374-11384). To check if PACAP might also modulate AMPA receptor function, we tested its effects on AMPA receptor-mediated synaptic currents on CA1 pyramidal neurons, using the patch clamp technique on hippocampal slices. In the presence of the NMDA antagonist D-AP5, PACAP (10 nM) reduced the amplitude of excitatory postsynaptic currents (EPSCs) evoked in CA1 pyramidal neurons by stimulation of Schaffer collaterals. Following a paired-pulse stimulation protocol, the paired-pulse ratio was unaffected in most neurons, suggesting that the AMPA-mediated EPSC was modulated by PACAP mainly at a postsynaptic level. PACAP also modulated the currents induced on CA1 pyramidal neurons by applications of either glutamate or AMPA. The effects of PACAP were dose-dependent: at a 0.5 nM dose, PACAP increased AMPA-mediated current; such effect was blocked by PACAP 6-38, a selective antagonist of PAC1 receptors. The enhancement of AMPA-mediated current by PACAP 0.5 nM was abolished when cAMPS-Rp, a PKA inhibitor, was added to the intracellular solution. At a 10 nM concentration, PACAP reduced AMPA-mediated current; such effect was not blocked by PACAP 6-38. The inhibitory effect of 10 nM PACAP was mimicked by Bay 55-9837 (a selective agonist of VPAC2 receptors), persisted in the presence of intracellular BAPTA and was abolished by intracellular cAMPS-Rp. Stimulation-evoked EPSCs in CA1 neurons were significantly reduced following application of the PAC1 antagonist PACAP 6-38; this result indicates that PAC1 receptors in the CA1 region are tonically activated by endogenous PACAP and enhance CA3-CA1 synaptic transmission. Our results show that PACAP differentially modulates AMPA receptor-mediated current in CA1 pyramidal neurons by activation of PAC1 and VPAC2 receptors, both involving the cAMP/PKA pathway; the functional significance will be discussed in light of the multiple effects exerted by PACAP on the CA3-CA1 synapse at different levels.

Noradrenaline modulates neuronal responses to GABA in vestibular nuclei

The effects of noradrenaline (NA) on the inhibitory responses to GABA were studied in vivo in neurons of the vestibular nuclei of the rat using extracellular recordings of single unit electrical activity and a microiontophoretic technique of drug application in loco. NA application influenced GABA-evoked inhibitions in 82% of tested neurons, depressing them in 42% and enhancing them in 40% of cases. The more frequent action of NA on GABA responses was depressive in lateral and superior vestibular nuclei (50% of neurons) and enhancing in the remaining nuclei (56% of neurons). The most intense effect of NA application was the enhancement of GABA responses induced in a population of lateral vestibular nucleus neurons, characterized by a background firing rate significantly higher than that of other units. The alpha(2) noradrenergic receptor agonist clonidine mimicked the enhancing action of NA on GABA responses; this action was blocked by application of the specific alpha(2) antagonist yohimbine. The beta adrenergic agonist isoproterenol induced either depressive or enhancing effects on GABA responses; the former more than the latter were totally or partially blocked by application of the beta antagonist timolol. It is concluded that NA enhances GABA responses by acting on noradrenergic alpha(2) and to a lesser extent beta receptors, whereas depressive action involves beta receptors only. These results confirm the hypothesis that the noradrenergic system participates in the regulation of the vestibulospinal and the vestibulo-ocular reflexes and suggest that conspicuous changes of NA content in brain due to aging or stress could lead to a deterioration in the mechanisms of normal vestibular function.

Inhibitory effects of N-acetylcysteine on the functional responses of human eosinophils in vitro

BACKGROUND

Oxidative stress appears to be relevant in the pathogenesis of inflammation in allergic diseases like bronchial asthma. Eosinophils are oxidant-sensitive cells considered as key effectors in allergic inflammation.

OBJECTIVE

The aim of this work was to study the effects of the clinically used antioxidant N-acetyl-L-cysteine (NAC) on the functional responses of human-isolated eosinophils.

METHODS

Human eosinophils were purified from the blood of healthy donors by a magnetic bead separation system. The effects of NAC were investigated on the generation of reactive oxygen species (chemiluminescence and flow cytometry), Ca(2+) signal (fluorimetry), intracellular glutathione (GSH; flow cytometry), p47(phox)-p67(phox) translocation (Western blot) and eosinophil cationic protein (ECP) release (radioimmunoassay).

RESULTS

NAC (0.1-1 mm) inhibited the extracellular generation of oxygen species induced by N-formyl-L-methionyl-L-leucyl-L-phenylalanine (fMLP) and eotaxin (in the presence of IL-5) with -logIC(50) values of 3.61+/-0.03 and 3.36+/-0.09, respectively. Also, the intracellular generation of hydrogen peroxide was virtually abolished by NAC (0.5-1 mm). NAC (1 mm) did not alter the fMLP-induced Ca(2+) signal but augmented the eosinophil content of reduced GSH and inhibited p47(phox)-p67(phox) translocation. NAC inhibited the release of ECP ( approximately 90% inhibition at 1 mm) from fMLP-activated eosinophils.

CONCLUSION

Inhibition by NAC of human eosinophil functions in vitro is potentially useful in the treatment of allergic inflammation.

Aminergic control of neuronal firing rate in thalamic motor nuclei of the rat

The effects induced on neuronal firing by microiontophoretic application of the biological amines noradrenaline (NA) and 5-hydroxytryptamine (5-HT) were studied "in vivo" in ventral-anterior (VA) and ventrolateral (VL) thalamic motor nuclei of anaesthetized rats. In both nuclei the amines had a mostly depressive action on neuronal firing rate, the percentage of units responsive to NA application (88%) being higher than to 5-HT (72%). Short-lasting (less than 2 min) and long lasting (up to 20 min) inhibitory responses were recorded, the former mostly evoked by NA and the latter by 5-HT ejection. In some cases 5-HT application had no effect on the firing rate but modified the firing pattern. NA-evoked responses were significantly more intense in VL than in VA neurons. Short-lasting inhibitory responses similar to NA-induced effects were evoked by the alpha2 adrenergic receptor agonist clonidine and to a lesser extent by the beta adrenergic receptor agonist isoproterenol. Inhibitory responses to 5-HT were partially mimicked by application of the 5-HT(1A) receptor agonist 8-hydroxy-2(di-n-propylamino)tetralin (8-OH-DPAT) and of the 5-HT2 receptor agonist alpha-methyl-5-hydroxytryptamine (ALPHA-MET-5-HT). The latter evoked excitatory responses in some cases. Both 5-HT agonists were more effective on VA than on VL neurons. The effects evoked by agonists were at least partially blocked by respective antagonists. These results suggest that although both 5-HT and NA depress neuronal firing rate, their effects differ in time course and in the amount of inhibition; besides aminergic modulation is differently exerted on VA and VL.

Effects of 5-hydroxytryptamine on the neuronal firing rate of bulbar reticular neurons

The effects of 5-hydroxytryptamine (5-HT) on neuronal firing rate were studied in the reticular gigantocellular nucleus (GRN) and, for a comparison, in the interstitial (IRN), the parvicellular (PRN) and the lateral (LRN) nuclei, sharing some of GRN functional characteristics. Unitary extracellular recordings performed in anesthetized rats demonstrated that microiontophoretic application of 5-HT modulated the background firing rate in 92% of GRN, in 100% of IRN and LRN, and in 77% of PRN tested neurons. In GRN, 5-HT application induced excitatory responses in 49% of the neurons tested and inhibitions in 43% of them. Both types of effects were dose dependent and appeared scattered throughout the nucleus. Enhancements and decreases of firing rate in response to 5-HT application were also recorded in IRN (58% and 42% respectively), LRN (43% and 57%) and PRN (36% and 41%). The 5-HT(1A) receptor agonist 8-hydroxy-2(di-n-propylamino)tetralin (8-OH-DPAT) mimicked 5-HT evoked inhibitions in all the nuclei tested and induced weak inhibitory responses also in neurons excited by 5-HT. The 5-HT2A receptor agonist alphamethyl-5-hydroxytryptamine (alpha-me-5-HT) mimicked excitatory as well as inhibitory responses to 5-HT, the former prevailing in GRN and the latter in the remaining reticular nuclei. Both excitatory and inhibitory responses to 5-HT were partially or totally blocked by the application of 5-HT2 receptor antagonist ketanserin. It is concluded that an extended, strong and differentiated control is exerted by 5-HT on the electrical activity of bulbar reticular neurons. Both 5-HT(1A) and 5-HT(2A) receptors mediate these effects, but the involvement of other receptors appears probable.

Alpha2- and beta-adrenoceptors differentially modulate GABAA- and GABAB-mediated inhibition of red nucleus neuronal firing

In mesencephalic red nucleus (RN), GABA-induced inhibition of neuronal firing is modulated by noradrenaline acting on alpha2- and beta-adrenoceptors. Since both GABAA and GABAB receptors are present in the rat RN, we have recorded the firing activity of RN neurons in vivo from anaesthetized rats to study how GABAA- and GABAB-mediated effects are modulated by either alpha2- or beta-adrenoceptor activation. Both the GABAA agonist isoguvacine and the GABAB agonist baclofen depressed the firing of RN neurons. During simultaneous application of clonidine, an alpha2-adrenoceptor agonist, half of the isoguvacine- and baclofen-mediated responses were modified: isoguvacine-mediated inhibition was enhanced by 97% without any change in effect duration, whereas baclofen responses were either increased or slightly reduced in the same number of cases. Application of isoprenaline, a beta-adrenoceptor agonist, increased isoguvacine effect in 66% of neurons without modifying effect duration; the amount of increase (43%) was significantly lower than that induced by clonidine. On the other hand, in the presence of isoprenaline, baclofen response was reduced in 72% of neurons with respect to both the amount (52%) and the duration (34%) of effect. Taken together, these results indicate that alpha2-adrenoceptors mainly enhance GABAA-induced inhibition and induce mixed effects on GABAB response; on the other side, beta-adrenoceptors exert an opposite modulation on GABA effects, respectively, enhancing and depressing GABAA- and GABAB-mediated responses.

[General Articles] Intracellular Thiol Concentration Modulating Inflammatory Response: Influence on the Regulation of Cell Functions Through Cysteine Prodrug Approach

Oxidative stress is defined as the consequence of overpowering of the immune system's reaction, which causes increased production of the reactive oxidative species (ROS) greater than the antioxidant protection. Tissue injury and oxidation of the circulating molecules may be the consequences. Moreover, the sulphur-containing amino acids (SAA) fate is perturbed during stress. The altered biochemical rules during inflammation weaken the anti-oxidant mechanism, and the extra-supply of SAA under inflammatory conditions can help to restore homeostasis. In brief, the main biochemical steps during inflammation are: The production of Cytokines, Acute Phase Protein, and Glutathione (GSH) pool are strongly modified during inflammation. The GSH participates in many important physiological processes controlling the homeostasis of the cells. A higher demand of Cysteine (Cys) supply causes difficulties in maintaining a constant GSH level. The role of GSH as a key regulator of thiol redox intracellular balance is established. This reveals that GSH is essential in regulating the cell's life cycle and that the reduction of intracellular GSH contributes to chronic inflammation. The fact that Cys availability is generally a limiting factor for the GSH synthesis stimulated the development of a pharmacologically useful Cys pro-drug. The simplest derivative is N-acetylcysteine (NAC), which appears to be the prototype of all Cys suppliers. Different approaches are presented here.

Oral N-acetylcysteine reduces bleomycin-induced lung damage and mucin Muc5ac expression in rats

Oxidative stress is involved in the pathogenesis of pulmonary fibrosis, therefore antioxidants may be of therapeutic value. Clinical work indicates that N-acetylcysteine (NAC) may be beneficial in this disease. The activity of this antioxidant was examined on bleomycin-induced lung damage, mucus secretory cells hyperplasia and mucin Muc5ac gene expression in rats. NAC (3 mmol x kg(-1) x day(-1)) or saline was given orally to Sprague-Dawley rats for 1 week prior to a single intratracheal instillation of bleomycin (2.5 U x kg(-1)) and for 14 days postinstillation. NAC decreased collagen deposition in bleomycin-exposed rats (hydroxyproline content was 4,257+/-323 and 3,200+/-192 microg x lung(-1) in vehicle- and NAC-treated rats, respectively) and lessened the fibrotic area assessed by morphometric analysis. The bleomycin-induced increases in lung tumour necrosis factor-alpha and myeloperoxidase activity were reduced by NAC treatment. The numbers of mucus secretory cells in airway epithelium, and the Muc5ac messenger ribonucleic acid and protein expression, were markedly augmented in rats exposed to bleomycin. These changes were significantly reduced in NAC-treated rats. These results indicate that bleomycin increases the number of airway secretory cells and their mucin production, and that oral N-acetylcysteine improved pulmonary lesions and reduced the mucus hypersecretion in the bleomycin rat model.

The regulation of sulphurated amino acid junctions: fact or fiction in the field of inflammation?

The diet of industrialised countries is usually rich in amino acids, which are in part used as a source of calories. However, metabolic alterations are observed in diseased patients and a preferential retention of Sulphurated Amino Acids (SAA) occurs during the inflammatory response. Moreover, it has been demonstrated in a model of an acute sepsis phase of rats that the metabolism of Cysteine is modified. The liver converts Cysteine at a different ratio of Sulphate to Taurine (Tau) i.e. the sulphate production decreases while the Tau conversion increases. The Glutathione (GSH) concentration is greater in the liver, kidneys and other organs and the Cysteine incorporation into proteins is higher in the spleen, lungs and plasma (Acute Phase Proteins) while the Albumin level decreases. The pro-inflammatory cytokines such as Interleukin-1, Interleukin-6 and TNF- alpha are the main initiators that alter protein and amino acid metabolism. Another important phenomenon is the impairment of Methionine conversion to Cysteine during stress. For example, premature infants or AIDS patients are capable of synthesizing Cysteine from Methionine at a much lower rate. Thus, the metabolic flow through the trans-sulphuration path may be inadequate to meet the Cysteine demand under critical conditions. In this complex picture, an SAA supply may contribute to an immune system regulation.

Oral N-acetylcysteine attenuates the rat pulmonary inflammatory response to antigen

Oxidative stress is involved in the pathophysiology of inflammatory airway diseases including asthma; therefore, antioxidants might be of clinical benefit in asthma treatment. In the present study, the effects of N-acetylcysteine on sensitised brown Norway rats were examined. N-Acetylcysteine (3 mmol kg body weight(-1) administered orally) was given daily for 1 week before challenge and various antigen-induced pulmonary responses were studied. Antigen exposure increased lipid peroxidation in bronchoalveolar lavage fluid (BALF) and oxidised glutathione levels in lung tissue 2 h after challenge. Lung nuclear transcription factor-KB-binding activity was increased 2 h after challenge, and BALF tumour necrosis factor-alpha and inducible nitric oxide synthase expression in lungs peaked 4 h after challenge. Expression of intercellular adhesion molecule-1 and mucin MUC5AC was also increased 4 h after challenge. These changes in oxidant status, transcription factor activation, and inflammatory cytokine and gene expression were reduced by N-acetylcysteine. This thiol did not affect the immediate bronchospasm reaction to antigen in anaesthetised rats but inhibited airways hyperresponsiveness to 5-hydroxytryptamine and the augmented eosinophil numbers in BALF, which appear 24 h after exposure of conscious rats to antigen aerosol, and abolished antigen-induced extravasation of Evans blue into BALF. These results indicate that oral N-acetylcysteine exerts an antioxidant protective effect and attenuates pulmonary inflammation in experimental asthma.

CuZn-superoxide dismutase in human thymus: immunocytochemical localisation and secretion in thymus-derived epithelial and fibroblast cell lines

CuZn-superoxide dismutase (SOD) plays a key role in mediating the cellular response to oxidative stress. Its expression in normal thymus was investigated by immunohistochemical techniques and CD3-, CD68- and cytokeratin-specific staining, in order to identify thymocytes, macrophages and epithelial components. Immunocytochemical studies showed an overall CuZn-SOD thymic distribution with a prevailing concentration within thymic medulla. The analysis of CuZn-SOD release by thymus-derived epithelial and fibroblast cell lines showed the ability of both cell lines to release the anti-oxidant enzyme, especially in the presence of stress conditions as represented by serum and nutrient deprivation. These data suggest that CuZn-SOD could be a relevant antioxidant paracrine molecule in human thymus.

Effectiveness of oral N -acetylcysteine in a rat experimental model of asthma

Oxidative stress appears to be relevant to asthma pathogenesis. Therefore, the effectiveness of the antioxidant N -acetylcysteine was examined on antigen-induced pulmonary responses in sensitized Brown-Norway rats. N -acetylcysteine (oral, 1 mmol kg(-1)per day for 7 days before challenge) did not reduce the immediate bronchospasm that followed aerosol antigen exposure but prevented airway hyperreactivity to 5-hydroxytryptamine at 24 h after antigen challenge, and reduced the eosinophils (from 0.178 +/- 0.038 in the absence to 0.064 +/- 0.020 x10(6)cells ml(-1)in the presence of N -acetylcysteine;P< 0.05), and Evans blue dye extravasation in bronchoalveolar lavage fluid. Taurine levels in bronchoalveolar lavage fluid from antigen-challenged rats were higher than control values but treatment with N -acetylcysteine failed to further increase these augmented levels. In conclusion, oral N -acetylcysteine showed beneficial effects in an in vivo model of experimental asthma, which confirm and extend the previous positive findings obtained in other models of lung injury.

Influence of serotonin on the glutamate-induced excitations of secondary vestibular neurons in the rat

The excitatory responses evoked by glutamate and its agonists in secondary vestibular neurons of the rat were studied during microiontophoretic application of 5-hydroxytryptamine (5-HT). Ejection of 5-HT modified neuronal responsiveness to glutamate in 86% of the studied units, the effect being a depression of the excitatory responses in two-thirds of cases and an enhancement in the remaining third. 5-HT was also effective in modifying 94% of the responses evoked by N-methyl-d-aspartate (NMDA), inducing a depressive effect in 76% of cases and an enhancement in the remaining ones. Quisqualate-evoked effects were depressed and enhanced by 5-HT in about the same number of cases; in contrast, kainate-evoked responses were enhanced. The depressive action of 5-HT was mimicked by application of alpha-methyl-5-hydroxytryptamine (alpha-Me-5-HT), a 5-HT(2) receptor agonist, whereas the enhancing effect could be evoked by application of 8-hydroxy-2(di-n-propylamino)tetralin (8-OH-DPAT), a selective 5-HT(1A) receptor agonist. The 5-HT(2) receptor antagonist ketanserin was able to reduce, but not to block totally, the depressive action of 5-HT on glutamate- or NMDA-evoked responses. No significant difference was detected between neuronal responses in the lateral and the superior vestibular nucleus. These results indicate that 5-HT is able to modulate the responsiveness of secondary vestibular neurons to excitatory amino acids. Its action is mostly depressive, involves 5-HT(2) receptors, and is exerted on NMDA receptors. A minor involvement of other 5-HT receptors (at least 5-HT(1A)) and other glutamate receptors (for quisqualate and kainate) in the modulatory action of 5-HT is plausible.

Effects of taurine on pulmonary responses to antigen in sensitized Brown-Norway rats

Oxidative stress appears relevant to asthma. Therefore, the effects of the antioxidant taurine (oral, 1 and 3 mmol x kg(-1) x day(-1) for 7 days before challenge) were examined on antigen-induced responses in sensitized Brown-Norway rats. Taurine did not reduce the bronchospasm produced by aerosol antigen but prevented airway hyperreactivity to 5-hydroxytryptamine (5-HT) at 24 h after antigen exposure, and reduced the eosinophils (from 0.178+/-0.038x10(6) to 0.044+/-0.014x10(6)* and 0.048+/-0.013x10(6)* cells ml(-1) in antigen and antigen+taurine 1 or 3 mmol x kg(-1), respectively; *P<0.05 vs. antigen), lipid hydroperoxides, and Evans blue dye extravasation in bronchoalveolar lavage fluid. Taurine levels in bronchoalveolar lavage fluid from antigen-challenged rats were higher than control values but treatment with taurine failed to further increase these levels. In conclusion, oral taurine showed beneficial effects in an in vivo model of experimental asthma, which confirm and extend the previous positive findings obtained in other models of lung injury.

Attenuation by oral N-acetylcysteine of bleomycin-induced lung injury in rats

Antioxidant therapy may be useful in diseases with impaired oxidant-antioxidant balance such as pulmonary fibrosis. This study examines the effect of N-acetylcysteine (NAC) on bleomycin-induced lung fibrosis in rats. NAC (3 mmol x kg(-1); oral) was given daily from 1 week prior to a single intratracheal instillation of bleomycin (2.5 U x kg(-1)) or saline, until 14 days postinstillation. NAC partially decreased the augmented collagen deposition in bleomycin-exposed rats (hydroxyproline content was 4,354+/-386 and 3,416+/-326 microg x lung(-1) in vehicle-treated and NAC-treated rats, respectively; p < 0.05). The histological assessment using a semiquantitative score showed less collagen deposition and inflammatory cells in NAC-treated rats compared to those receiving bleomycin alone. NAC failed to inhibit the bleomycin-induced increases in lung wet weight and in cell counts and protein levels of bronchoalveolar lavage fluid, but significantly increased total glutathione and taurine levels in bronchoalveolar lavage fluid. These results indicate that oral N-acetylcysteine improves the pulmonary antioxidant protection and may be useful in reducing lung damage produced by bleomycin.

Serotonin modifies the neuronal inhibitory responses to gamma-aminobutyric acid in the red nucleus: a microiontophoretic study in the rat

The effects of 5-hydroxytryptamine (5-HT) on the inhibitory responses evoked by gamma-aminobutyric acid (GABA) in neurons of the red nucleus (RN) were studied using a microiontophoretic technique. Extracellular unitary recordings performed in anesthetized rats demonstrated that 5-HT ejection influenced GABA-evoked inhibition in 94% of RN neurons, enhancing them in 52% and depressing them in 46% of cases. Both effects were specific and dose-dependent,although enhancements or depressions of the GABA responses were respectively inversely and directly related to the doses of 5-HT applied. The type of modulation exerted by 5-HT on the GABA responses was independent of the action of the amine on background firing. In fact, 5-HT induced an enhancement of the GABA responses in neurons mostly located in the rostral RN and a depression in those in the caudal RN. The application of 8-hydroxy-2(di-n-propylamino)tetralin, a specific 5-HT(1A) receptor agonist, enhanced GABA responses, whereas alpha-methyl-5-hydroxytryptamine, a 5-HT(2A) receptor agonist, depressed them. Both the 5-HT(2) antagonist methysergide and the 5-HT(2A) selective antagonist ketanserin were able to block partially or totally the depressive action of 5-HT on GABA responses. In contrast, the same 5-HT antagonists mimicked the enhancing action of 5-HT on the GABA responses or were ineffective. Application of bicuculline, a GABA(A) receptor antagonist, enhanced the excitatory action of 5-HT on the background firing and slightly reduced the inhibitory action. It is concluded that 5-HT is able to modulate GABA-evoked responses in RN neurons by acting on both 5-HT(1A) and 5-HT(2A) receptors. The functional significance of a serotonergic control on GABAergic inhibitory effects in RN is discussed.

Neurotransmitter-mediated control of neuronal firing in the red nucleus of the rat: reciprocal modulation between noradrenaline and GABA

The electrical activity of neurons from the red nucleus, a mesencephalic structure involved in motor control, is under the influence of several neurotransmitters released from afferent fibers and/or from local interneurons. We have investigated the combined effects of gamma-aminobutyric acid (GABA) and noradrenaline (NA), both present at high levels in the red nucleus, on the firing activity of single rubral neurons recorded extracellularly in vivo on anesthetized adult rats. NA inhibited the firing activity of a large part of rubral neurons and induced excitatory or biphasic inhibitory/excitatory effects in a smaller group of cells. Neuronal firing was also inhibited by GABA in all the cells studied. When the effect of GABA was tested during continuous applications of NA, the magnitude of GABA response was modified in 58% of the cells: the effect of GABA was potentiated by NA in half of the responding neurons and was decreased in the remaining half. NA-induced potentiation of GABA response was mimicked by the alpha(2)-adrenoceptor agonist clonidine and was abolished by the alpha(2)-adrenoceptor antagonist yohimbine. On the other side, the decrease of GABA response was reproduced by the beta-adrenoceptor agonist isoprenaline and was blocked by timolol, an antagonist of beta-adrenoceptors. Neuronal firing activity was reduced by nipecotic acid, an inhibitor of GABA reuptake mechanism, and was instead increased during application of the GABA(A) receptor antagonist bicuculline, suggesting that rubral neurons in vivo were under tonic control by endogenous GABA. Both the inhibitory and the excitatory effects of NA were reduced in the presence of nipecotic acid and were instead potentiated during application of bicuculline, suggesting that NA responses were modified by endogenous GABA. Taken together, our results indicate a reciprocal modulation between the effects of GABA and NA on neuronal firing activity in the red nucleus of the rat: GABA depresses the responsiveness of rubral neurons to NA, whereas NA is able either to potentiate or to decrease the effects of GABA by activation of alpha(2)- and beta-adrenoceptors, respectively. The functional significance of such interaction, as well as the possible implication in diseases affecting motor control, will be discussed.

Electromyographic effects of serotonin application into the lateral vestibular nucleus

Electromyographic responses (EMGs) of limb muscles were studied during microiontophoretic application of 5-hydroxytryptamine (5-HT) into the lateral vestibular nucleus (LVN) or the spinal vestibular nucleus (SpVe) of anaesthetized rats. The aim was to ascertain whether the level of 5-HT in these nuclei was able to modulate muscle responsiveness. Increased levels of 5-HT in LVN (and to a weaker extent in SpVe) enhanced the EMGs of proximal extensor muscles and depressed those of flexors. The 5-HT2A receptor antagonist ketanserin, applied into the LVN, prevented 5-HT effects on EMG-evoked responses. It is concluded that 5-HT can modulate the motor output via the vestibulospinal pathway, exerting a differential control over flexor and extensor muscles.

Secretion and increase of intracellular CuZn superoxide dismutase content in human neuroblastoma SK-N-BE cells subjected to oxidative stress

CuZn superoxide dismutase (SOD) secretion was detected in media of [35S]cysteine-labeled human neuroblastoma SK-N-BE cells precipitated with antihuman CuZn SOD antibodies. The ability of Fe2+/ascorbate oxidative stress to induce CuZn SOD in SK-N-BE cells was evaluated by Western blot analysis. The results showed that, like human hepatocarcinoma cells and human fibroblasts, SK-N-BE cells secrete CuZn SOD. In addition, the CuZn SOD concentration was higher in cells subjected to oxidative stress than in unstressed cells. The secretion of CuZn SOD and the ability of Fe2+/ascorbate to increase its protein content in SK-N-BE cells indicates that this enzyme protects the brain from damage induced by oxidative stress.

5-Hydroxytryptamine modifies neuronal responses to glutamate in the red nucleus of the rat

The effects of 5-hydroxytryptamine (5-HT) on the responses of red nucleus (RN) neurones to glutamate (glu) and its agonists were studied using a microiontophoretic technique in anaesthetised rats. Extracellular unitary recordings of RN neuronal activity showed that 5-HT application induced a significant and reversible depression of glu-evoked excitations in 85% of the RN units tested. This effect was independent of the action of the amine on background firing, which appeared enhanced in the majority of cases but was either depressed or uninfluenced in other cases. Microiontophoretic 5-HT also depressed the excitatory responses evoked in RN neurones by electrical stimulation of sensorimotor cortex. Methysergide application, which prevented the enhancing effects of 5-HT on the background firing, was scarcely effective in antagonising the depression of glu responses. In contrast, the serotonergic effects on the glu responses were reduced by the iontophoretically applied antagonist of 5-HT1A receptors, NAN-190. Microiontophoretic 5-HT was also able to influence the neuronal responses evoked by glu agonists quisqualate (quis) and N-methyl-D-aspartate (NMDA), acting on non-NMDA and NMDA receptors respectively. In fact 5-HT depressed quis-evoked excitations and induced mixed effects on NMDA responses, which were reduced in 45%, enhanced in 34% and unmodified in 21% of the units tested. These results suggest that 5-HT is able to modulate the motor glutamatergic input to RN by acting mostly on non-NMDA receptors. The modulation of non-NMDA and NMDA receptors by 5-HT in the RN appears significant and its functional meaning is discussed.

Noradrenaline modifies the spontaneous spiking activity of red nucleus neurons in the rat by activation of alpha 2- and beta-adrenoceptors

We have investigated the effects of noradrenaline (NA) on the spontaneous firing activity of red nucleus (RN) neurons recorded extracellularly in anesthetized rats by using an in vivo electrophysiological technique. Microiontophoretic applications of NA (5-100 nA for 30 s) modified the background firing rate in 99 out of 124 neurons and three different patterns of response were observed in distinct cells. In 61% of the responding neurons NA decreased the mean firing rate, whereas 22% of the neurons responded to NA application with an increase of their spiking activity; in a smaller group of cells (17%) NA exerted a biphasic inhibitory/excitatory effect on the spontaneous firing rate. The effects of NA were reversible and dose-dependent. From histological examination, the neurons responding to NA with a purely inhibitory effect were scattered throughout the RN. On the other hand, the neurons responding to NA with an excitation were found to be more numerous in the dorso-medial part of the RN, whereas the neurons in which NA induced biphasic effects appeared to be segregated in the outer lateral portion of the RN. The alpha 2-adrenoceptor antagonist yohimbine completely blocked the inhibitory effect of NA but was unable to antagonize the excitatory response. In addition, the inhibitory effect of NA was mimicked by clonidine, a selective agonist of alpha 2-adrenoceptors; clonidine had no effect on those cells which responded to NA with an increase of the mean firing rate. The excitatory effect of NA was mimicked by the beta-receptor agonist isoprenaline and was antagonized by timolol, a selective antagonist of beta-adrenoceptors. Isoprenaline was ineffective in those cells in which NA exerted inhibitory responses. Taken together, our results indicate that the inhibitory effect of NA on the firing activity of rat RN neurons were mediated by alpha 2-adrenoceptors, whereas beta-adrenoceptors were responsible for the excitatory effects.

Evidence for secretion of cytosolic CuZn superoxide dismutase by Hep G2 cells and human fibroblasts

The role so far ascribed to intracellular CuZn superoxide dismutase is that of an intracellular scavenger of oxygen radicals. However, other functions of cytosolic CuZn superoxide dismutase have been hypothesized. For example, CuZn superoxide dismutase incubated with rat hepatocyte cells in culture inhibits 3-hydroxy-3methylglutaryl CoA reductase, thereby reducing cholesterol synthesis. We recently demonstrated the presence of surface membrane receptors for CuZn superoxide dismutase, suggesting possible autocrine or paracrine activities. The aim of the present study was to investigate whether cytosolic CuZn superoxide dismutase can be secreted by human hepatocarcinoma and fibroblast cells lines. Proteins in human hepatocellular carcinoma (Hep G2) cells and human fibroblasts were biosynthetically labelled with [35S]-cysteine; then cell lysates and media were immunoprecipitated with rabbit polyclonal anti-human CuZn superoxide dismutase antibodies and separated by 12% polyacrylamide gel electrophoresis. Both Hep G2 cells and human fibroblasts produce and secrete CuZn superoxide dismutase which was detectable in cells and medium as a single protein band with the same electrophoretic mobility as human erythrocyte CuZn superoxide dismutase. These data suggest that CuZn superoxide dismutase, an enzyme thus far considered to be located exclusively intracellularly is secreted by at least two cell lines. This is consistent with autocrine or paracrine roles for CuZn superoxide dismutase.

Investigation of the positive inotropic action of 6,7-dimethoxy-3-cyano-3,4-dihydrocarbostyril

6.7-Dimethoxy-3-cyano-3.4-dihydrocarbostyril (7A61, 1), a 2-quinolinone derivative, showed interesting cardiotonic properties in vitro. It exerted potent positive inotropic effects, without any change in heart rate, in guinea pig atrial preparations, and its effects were not dependent upon inhibition of phosphodiesterases, opening of Na+ channels, or inhibition of adenosine receptors. Notwithstanding its structural relationships with milrinone, vesnarinone, and other quinolinones endowed with cardiotonic activity, it appeared that 7A61 does not share any of the main mechanisms of action involved in the pharmacological activity of these compounds. Other experiments also excluded the involvement of other well known mechanisms of cardiac stimulation, such as adrenergic receptor activation or opening of Ca++ channels, the mode of action of 7A61 remaining unexplained. However, contrary to milrinone, 7A61 did not exert cardiotonic effects in human ventricular muscle preparations, thus discouraging further investigation. Although the lack of effect on human heart could not be predicted from the results obtained in several cardiac preparations commonly used in laboratory investigations, the scarce efficacy of 7A61 in comparison with milrinone in dog and cat papillary muscle and in guinea pig ventricular muscle suggests the utility of the latter preparations in laboratory experiments aimed at selecting new potential cardiotonic agents.

Neuronal responses to 5-hydroxytryptamine in the red nucleus of rats

The effects of microiontophoretic 5-hydroxytryptamine (5-HT) on the firing rate of red nucleus (RN) neurons were studied in urethane-anesthetized rats. The background discharge rate of almost all the neurons tested (97%) was modified by 5-HT, and generally increased (89%). Responses were dose dependent. Twenty-three percent of the excitatory responses were preceded by a short inhibitory phase. No significant difference in the effect of 5-HT was found between those RN neurons that project to the spinal cord and those that do not The excitatory responses to 5-HT were blocked or greatly reduced by the 5-HT antagonists methysergide and ketanserin, and were even reversed in some cases. The 5-HT2/5-HT1A antagonist spiperone, in small doses, also blocked the transient inhibitory phases in addition to the excitatory effects. In RN neurons exhibiting a short-lasting inhibition in the response to 5-HT, the 5-HT1A agonist 8-hydroxy-2(di-n-propyl-amino)tetralin (8-OH-DPAT) induced inhibitory effects. These results support the hypothesis that 5-HT exerts control throughout the RN, mostly by acting on 5-HT2 receptors. Furthermore, an influence of this amine on the electrical activity of small groups of RN neurons by 5-HT1A receptors, and eventually by different mechanisms, appears probable. The functional significance of serotoninergic control of RN neuronal activity is discussed.

Enhancement of tissue lipoperoxidation in propanil-treated rats

The i.p. injection of the herbicide propanil to male Sprague-Dawley rats increased the susceptibility to lipoperoxidation of liver and brain rat microsomes. A liver damage produced by propanil treatment was demonstrated by decreased serum levels of cholesterol and triglycerides as compared to serum levels of the lipids in control rats. The cellular damage of rat liver was also confirmed by the increased serum levels of aspartate aminotransferase and alkaline phosphatase activities observed in propanil-treated rats as compared to their activities in control rats.

Circadian rhythms of lipid and apolipoprotein pattern in adult fasted rats

Data on circadian rhythms of serum lipids and apolipoproteins in animals and in human subjects are scarce. The goal of this study was to investigate the existence of circadian rhythms in the lipids and apolipoproteins of fasted rats. We showed that in fasted rats well-defined circadian rhythms were present in total serum triglycerides and in cholesterol and triglycerides of very low density lipoprotein (VLDL), intermediate density lipoprotein-low density lipoprotein (IDL-LDL) and high density lipoprotein (HDL). Moreover, our data clearly show that the circadian rhythm of lipoproteins is accompanied by a well defined circadian rhythm of B apoprotein, in all lipoprotein classes examined.