Peptidogalactomannan from Histoplasma capsulatum yeast cell wall: role of the chemical structure in recognition and activation by peritoneal macrophages.

Histoplasma capsulatum is the causative agent of histoplasmosis, a systemic disease responsible for most reported causes of morbidity and mortality among immunosuppressed individuals. Peptidogalactomannan (pGM) was purified from the yeast cell wall of H. capsulatum isolated from bats, and its structure and involvement in modulating the host immune response were evaluated. Gas chromatography, methylation analysis, and two-dimensional nuclear magnetic resonance (2D-NMR) were used for the structural characterization of pGM. Methylation and 2D-NMR data revealed that pGM comprises a main chain containing α-D-Manp (1 → 6) residues substituted at O-2 by α-D-Manp (1 → 2)-linked side chains, non-reducing end units of α-D-Galf, or ß-D-Galp linked (1→ 6) to α-D-Manp side chains. The involvement of H. capsulatum pGM in antigenic reactivity and in interactions with macrophages was demonstrated by ELISA and phagocytosis assay, respectively. The importance of the carbohydrate and protein moieties of pGM in sera reactivity was evaluated. Periodate oxidation abolished much pGM antigenic reactivity, suggesting that the sugar moiety is the most immunogenic part of pGM. Reactivity slightly decreased in pGM treated with proteinase K, suggesting that the peptide moiety plays a minor role in pGM antigenicity. In vitro experiments suggested that pGM is involved in the phagocytosis of H. capsulatum yeast and induction of IL-10 and IFN-γ secretion by peritoneal macrophages from C57BL/6 mice. These findings demonstrated the role of pGM in the H. capsulatum-host interaction.

Impression cytology in the evaluation of ocular surface tumors: review article / Citologia de impressão na avaliação de tumores da superfície ocular: artigo de revisão

Impression cytology (IC) has been widely used as a method for evaluating the ocular surface and superficial cells layers in the diagnosis and follow-up after treatment of several ocular surface tumors of both epithelial and melanocytic origin. Information regarding this can be found in the English-language literature since 1992. Using either cellulose acetate or Biopore membranes for specimen collection, a high correlation has been found between IC and tissue histology. Compared with exfoliative cytology with spatula, IC is less traumatic to the patient’s eye, provides a precise location of the area being studied, and allows accurate observation of the cells the way they exist in vivo. The additional advantage of IC is the preservation of limbal stem cells responsible for continuous corneal epithelium renewal; these can be affected after incisional or excisional biopsy at the corneoscleral limbus, which is the most frequent site of appearance of tumors in the stratified epithelium. Treatment for ocular surface squamous neoplasia has historically included surgery, but nonsurgical interventions have also been adopted. Hence, in certain cases, ophthalmologists may prefer interventions less invasive than surgical biopsy such as of impression cytology for both initial diagnosis and therapeutic monitoring of treatment for ocular surface lesions. Nevertheless, it should be considered that IC may be less helpful if the results conflict with the clinical picture or if the clinical diagnosis is uncertain and results are negative. In such cases, surgical biopsy is required for accurate diagnosis. The purpose of this review is to examine the published literature on the utilization of IC for the diagnosis and management of ocular surface tumors and to discuss the requirement for further investigation on the subject.

A citologia de impressão (CI) tem sido amplamente utilizada como um método de avaliação da superfície ocular e das camadas de células superficiais no diagnóstico e no seguimento após tratamento de vários tumores da superfície ocular de origem epitelial ou melanocítica. As informações podem sem encontradas na literatura em língua inglesa desde 1992. Utilizando-se de membranas de acetato de celulose ou Biopore na coleta dos espécimes, uma alta correlação tem sido encontrada entre a CI e a histologia do tecido. Comparando-se com a citologia esfoliativa, a citologia de impressão é menos traumática para o olho do paciente, fornece uma localização precisa da área estudada e permite ver as células da forma como elas organizam-se in vivo. A vantagem adicional da citologia de impressão é a preservação das células- tronco germinativas responsáveis pela renovação contínua do epitélio da córnea. Elas podem ser afetadas após biópsia cirúrgica na região do limbo que é o sítio mais frequentemente acometido pelos tumores do epitélio estratificado. O tratamento para a neoplasia escamosa da superfície ocular tem sido historicamente a cirurgia, mas intervenções não cirúrgicas também foram adotadas. Por esta razão, em certos casos, oftalmologistas podem recorrer a formas menos invasivas que a biópsia cirúrgica (como a citologia de impressão) tanto para o diagnóstico inicial quanto para o monitoramento terapêutico das lesões da superfície ocular. No entanto, deve-se ter em mente que a citologia de impressão deixa de ser útil quando seu resultado não coincide com o quadro clínico ou quando o diagnóstico clínico é incerto e o resultado da citologia de impressão negativo. Nesses casos, a biópsia cirúrgica deve ser realizada para o diagnóstico. O objetivo desta revisão é examinar a literatura sobre a utilização da citologia de impressão no diagnóstico e tratamento dos tumores da superfície ocular bem como discutir a necessidade de uma investigação mais aprofundada sobre o assunto.

A vanG-type locus in Clostridium argentinense.

OBJECTIVES: The objective was to study a new vanG-type locus in Clostridium argentinense vanGCar and to determine its impact on glycopeptide susceptibility of the host. METHODS: The whole genome of C. argentinense NCIB 10714 was sequenced using Illumina single-reads sequencing technology. The presence of vanGCar in seven C. argentinense strains was tested by PCR and its expression was tested by quantitative RT-PCR (qRT-PCR). Glycopeptide susceptibility was determined by the Etest procedure. RESULTS: The vanGCar locus contained four genes encoding a carboxypeptidase, a d-alanine:d-serine ligase, a serine transporter and a serine racemase, and was present in the seven C. argentinense studied. An AraC-type transcriptional regulator was found upstream from the genes. C. argentinense NCIB 10714 was susceptible to vancomycin and to teicoplanin. qRT-PCR experiments revealed that vanGCar was not expressed without or with induction by a subinhibitory concentration of vancomycin. CONCLUSIONS: The new vanGCar locus was cryptic in C. argentinense and intrinsic to this species. Emergence of vancomycin resistance in C. argentinense due to decryptification of the vanGCar gene cluster could occur.

Methicillin-resistant Staphylococcus aureus: an evolving pathogen.

The horizontal transmission of methicillin resistance to Staphylococcus aureus (MRSA) in hospital and community settings, and growing prevalence of these strains, presents a significant clinical challenge to the management of serious infections worldwide. While infection control initiatives have stemmed the rising prevalence, MRSA remains a significant pathogen. More recently, evidence that MRSA is becoming resistant to glycopeptides and newer therapies raises concern about the use of these therapies in clinical practice. Vancomycin resistance has become evident in select clinical settings through rising MICs, growing awareness of heteroresistance, and emergence of intermediate-resistant and fully resistant strains. While resistance to linezolid and daptomycin remains low overall, point mutations leading to resistance have been described for linezolid, and horizontal transmission of cfr-mediated resistance to linezolid has been reported in clinical isolates. These resistance trends for newer therapies highlight the ongoing need for new and more potent antimicrobial therapies.

The proteomic profile of Stichodactyla duerdeni secretion reveals the presence of a novel O-linked glycopeptide.

Sea anemones represent one of the emerging groups of interest concerning venomous animals in toxinology and the goal of the present work was the prospection, and the structural and functional characterization of the compounds present in the secretion of the sea anemone Stichodactyla duerdeni from Brazilian coast. We used a combination of offline RPC-MALDI-TOF and online nano-RPC-ESI-LTQ-Orbitrap proteomic techniques as well as functional bioassays. The mucus was milked by electric stimulation and fractionated by gel filtration on Sephadex G-50 yielding 5 main fractions. The low molecular weight fractions were further submitted to RP-HPLC resulting in 35 new subfractions that were subsequently analyzed by offline MALDI-TOF mass spectrometry. MALDI peptide mass fingerprinting yielded up to 134 different molecular masses, ranging from m/z 901 to 10,833. Among these subfractions, a new peptide of 3431Da, named U-SHTX-Sdd1, was purified and completely sequenced by automated Edman's degradation and tandem mass spectrometry. An analysis of U-SHTX-Sdd1 revealed a modified O-HexNAc-Threonine at position 1, which, at the best of our knowledge, constitutes the first sea anemone toxin reported with such post-translational modification. Because of its sequence similarity with other sea anemone toxins, the pharmacological activity of U-SHTX-Sdd1 was assessed by electrophysiological measurements using the two electrode voltage-clamp technique on cloned voltage-gated potassium channel subtypes, expressed in Xenopus laevis oocytes. However, U-SHTX-Sdd1 did not show activity on these channels. A large-scale proteomic approach was also employed to shed lights on the sea anemone compounds, and a total 67 proteins and peptides were identified. BIOLOGICAL SIGNIFICANCE: In this manuscript, we report an extensive characterization of S. duerdeni secretion by means of peptide mass fingerprinting and high-throughput proteome analyses. Also, we report the structure of a new glycopeptide by a combination of biochemical techniques. Despite the previous studies that described proteinaceous compounds present in sea anemone secretions, the number of reported primary sequences is still low. Thus, to access the scenery of protein components from S. duerdeni mucus, including their biological functions, a robust proteomic approach was used together with bioinformatic tools. The demonstrated strategy of analysis is perfectly suitable to other sea anemone secretions and animal venoms. Moreover, new peptide structures can arise contributing to the knowledge of the diversity of these animal peptides.

TD-1792 versus vancomycin for treatment of complicated skin and skin structure infections.

TD-1792 is a first-in-class glycopeptide-cephalosporin heterodimer that exhibits bactericidal activity against Gram-positive pathogens. We conducted a randomized, double-blind, active-control, phase II trial in patients with complicated skin and skin structure infections caused by suspected or confirmed Gram-positive organisms. Patients 18 to 65 years old were randomized to receive 7 to 14 days of either TD-1792 (2 mg/kg of body weight intravenously [i.v.] every 24 h [q24h]) or vancomycin (1 g i.v. q12h, with dosage regimens adjusted per site-specific procedures). A total of 197 patients were randomized and received at least one dose of study medication. Rates of clinical success at the test-of-cure evaluation were similar in all analysis populations. Among 170 clinically evaluable patients, cure rates were 91.7% and 90.7% in the TD-1792 and vancomycin groups, respectively (95% confidence interval [CI] of -7.9 to 9.7 for the difference). In microbiologically evaluable patients with methicillin-resistant Staphylococcus aureus at baseline (n = 75), cure rates were 94.7% in the TD-1792 group and 91.9% in the vancomycin group. Microbiological eradication of Gram-positive pathogens (n = 126) was achieved in 93.7% and 92.1% of patients in the TD-1792 and vancomycin groups, respectively. Seven patients were discontinued from study medication due to an adverse event (AE): 2 and 5 in the TD-1792 and vancomycin groups, respectively. AEs were of similar types and severities between the two groups, other than pruritus, which was more common in patients who received vancomycin. No patients in the TD-1792 group experienced a serious AE. This study supports further clinical development of TD-1792 in patients with Gram-positive infection.

Cysteine cathepsins in human carious dentin.

Matrix metalloproteinases (MMPs) are important in dentinal caries, and analysis of recent data demonstrates the presence of other collagen-degrading enzymes, cysteine cathepsins, in human dentin. This study aimed to examine the presence, source, and activity of cysteine cathepsins in human caries. Cathepsin B was detected with immunostaining. Saliva and dentin cysteine cathepsin and MMP activities on caries lesions were analyzed spectrofluorometrically. Immunostaining demonstrated stronger cathepsins B in carious than in healthy dentin. In carious dentin, cysteine cathepsin activity increased with increasing depth and age in chronic lesions, but decreased with age in active lesions. MMP activity decreased with age in both active and chronic lesions. Salivary MMP activities were higher in patients with active than chronic lesions and with increasing lesion depth, while cysteine cathepsin activities showed no differences. The results indicate that, along with MMPs, cysteine cathepsins are important, especially in active and deep caries.

Resistance or decreased susceptibility to glycopeptides, daptomycin, and linezolid in methicillin-resistant Staphylococcus aureus.

Methicillin-resistant Staphylococcus aureus (MRSA) with decreased susceptibility to glycopeptides can be categorized as first, heteroresistant to vancomycin (hVISA); second, with intermediate susceptibility to vancomycin (VISA); and third, fully resistant to vancomycin (VRSA). Whereas the hVISA and VISA isolates are characterized by increased cell wall thickness, activated cell wall synthesis and reduced autolysis, VRSA harbor the vanA gene cluster resulting in a remodeled peptidoglycan. Nonsusceptibility to daptomycin has been associated with changes in the structure and function of the cell envelope and surface charge. Linezolid resistance in MRSA is often associated with mutations in the 23S rRNA, although resistance mediated by an acquired gene (cfr encoding a 23S rRNA methyltransferase) has now been documented in several continents and in outbreak settings.

In vitro antimicrobial effect of bacteriocin PsVP-10 in combination with chlorhexidine and triclosan against Streptococcus mutans and Streptococcus sobrinus strains.

OBJECTIVES: To determine the minimal inhibitory concentrations (MICs) of bacteriocin PsVP-10, chlorhexidine and triclosan on S. mutans and S. sobrinus and to study the potential synergistic combination between these antimicrobial and the bacteriocin PsVP-10. DESIGN: Were determined MICs of bacteriocin PsVP-10, triclosan and chlorhexidine on strains of S. mutans and S. sobrinus, which formed a biofilm or did not form a biofilm. In addition, the synergistic effect was analysed by the determination of respective fractionary inhibitory concentrations (FICs) between bacteriocin PsVP-10 plus chlorhexidine and bacteriocin PsVP-10 plus triclosan. RESULTS: MICs of three antimicrobials used were higher in those bacterial strains, which formed a biofilm. An interesting synergistic effect on both studied species was observed when bacteriocin and chlorhexidine were combined. A slighter synergy was determined for the combination bacteriocin PsVP-10 and triclosan. CONCLUSIONS: The results showed that the combination of chlorhexidine bacteriocin PsVP-10 could reduce the number of cariogenic bacteria for in vitro studies. In the future this synergistic combination could be an alternative to antimicrobial therapy against S. mutans or S. sobrinus.

A new lipoglycopeptide: telavancin.

The increase in infections caused by resistant Gram-positive organisms has led to an urgent need for new antibiotics. Telavancin is a rapidly bactericidal lipoglycopeptide with multiple mechanisms of action, including concentration-dependent inhibition of bacterial cell wall synthesis and disruption of the functional integrity of the cell membrane. Telavancin is active against a wide variety of Gram-positive organisms including Staphylococcus aureus with resistance to methicillin, reduced susceptibility to vancomycin, and full resistance to vancomycin. Telavacin is approximately 90% protein bound; it has a serum half-life of around 8 h and a prolonged postantibiotic effect, allowing once daily administration. Telavancin is eliminated principally through the urine, requiring dose adjustment in patients with renal impairment. The efficacy and safety of telavancin was demonstrated in a large program of patients with complicated skin and skin structure infections. Development of resistance has not been detected in clinical strains. Adverse events include taste disturbance, nausea and vomiting; a small proportion of patients experienced reversible increase in serum creatinine. Two large Phase III studies in patients with healthcare associated pneumonia were recently completed. Telavancin has the potential to become an important therapeutic option to treat serious infections produced by resistant Gram-positive cocci, particularly those caused by methicillin-resistant S. aureus.

Potentiation of bradykinin effect by angiotensin-converting enzyme inhibition does not correlate with angiotensin-converting enzyme activity in the rat mesenteric arteries.

Angiotensin-converting enzyme (kininase II [ACE]) inhibitors are capable of potentiating bradykinin (BK) effects by enhancing the actions of bradykinin on B(2) receptors independent of blocking its inactivation. To investigate further the importance of ACE kininase activity on BK-induced vasodilation, we investigated the effect of inhibiting ACE, as well as other kininases, on both BK metabolism and vasodilator effect in preparations that exhibit increased ACE activity. Mesenteric arterial beds obtained from 1-kidney, 1-clip hypertensive rats presented augmented ACE and angiotensin I converting activities compared with normotensive rats. The isolated and perfused mesenteric beds were exposed to BK for 15 minutes in the absence or in the presence of kininase inhibitors; then, the perfusate was collected for analysis of the products of BK metabolism by high-performance liquid chromatography. BK was metabolized to the fragments BK(1-8), BK(1-7), and BK(1-5), and the recovery of intact BK was reduced by 47% in the hypertensive group. Recovery of BK was increased in both groups in the presence of a kininase I inhibitor and in the hypertensive group by neutral endopeptidase 24.11 inhibitor; however, ACE inhibition did not affect BK metabolism in both groups. In contrast, only the ACE inhibitor potentiated the vasodilator effect of BK in a mesenteric bed preconstricted with phenylephrine; the increase in BK effect, nevertheless, was not greater in arteries from hypertensive rats that presented an increased ACE activity when compared with those in the normotensive group. These data demonstrated that ACE inhibitor-induced potentiation of BK vasodilator effects is not related to their actions on BK degradation.

Effect of chronic ethanol consumption on endothelin-1 generation and conversion of exogenous big-endothelin-1 by the rat carotid artery.

The purpose of the present work was to investigate whether conversion of exogenous applied big-endothelin-1 (Big-ET-1) as well as the basal release and mRNA levels of endothelin-1 (ET-1) is altered by ethanol consumption in the rat carotid. The measurement of the contraction induced by Big-ET-1 served as an indicative of functional endothelin (ET)-converting enzyme (ECE) activity. Cumulative application of exogenous Big-ET-1 elicited a concentration-related contraction with the concentration-response curve shifted to the right when compared to ET-1. In endothelium-intact rings, phosphoramidon (1 mmol/l), a nonselective ECE/neutral endopeptidase (NEP) inhibitor, produced a rightward displacement of the concentration-response curves and reduced the maximal contractile response to Big-ET-1. However, in endothelium-denuded rings phosphoramidon reduced the maximum contraction for Big-ET-1 but did not alter the potency when compared to the curves obtained in the absence of the inhibitor. Ethanol consumption for 2, 6, or 10 weeks reduced the contractile effect elicited by Big-ET-1 in carotid rings with intact endothelium when compared to control or isocaloric rings. However, no differences on Big-ET-1-induced contraction were observed after endothelial denudation. On the other hand, ethanol consumption increased ET-1-induced contraction. Finally, chronic ethanol consumption did not alter either the mRNA levels for pre-pro-ET-1 nor the basal release of ET-1. The present findings show that chronic ethanol consumption does not alter the mRNA levels for ET-1 or its basal release in the rat carotid. Moreover, ethanol intake reduces the contraction induced by exogenously applied Big-ET-1 in carotid rings with intact endothelium, a fact that might be the result of a reduced conversion of this peptide by ECE on its mature active peptide ET-1.

Functional evidence of des-Arg10-kallidin enzymatic inactivating pathway in isolated human umbilical vein.

It has been known for many years that plasma and tissues contain a variety of enzymes capable of metabolizing kinins. The aim of the present study was to evaluate, by means of functional studies in a capacitance vessel such as the human umbilical vein (HUV), the possible role played by the metallopeptidases angiotensin-converting enzyme (ACE), neutral endopeptidase (NEP), and aminopeptidase M (APM) as an inactivating pathway of the B(1) receptor endogenous agonist des-Arg(10)-kallidin (DAKD). In HUV rings with and without endothelium, concentration-response curves (CRCs) to DAKD were determined after a 300-min incubation period, and enzymatic inhibitors were added to the organ baths 30 min before construction of the CRC. Presence of endothelial layer was confirmed by histological studies. There was a significant leftward shift observed in control HUV rings devoid of endothelium compared with intact tissues. Exposure to 1 microM captopril (ACE inhibitor) potentiated DAKD-elicited vasoconstrictor responses in HUV rings with endothelium while no such effect was observed in tissues devoid of endothelium. Application of 10 microM amastatin (APM inhibitor) induced a leftward shift of DAKD-elicited contractile responses in HUV with and without endothelium. On the other hand, 10 microM phosphoramidon (NEP inhibitor) showed no potentiating effect in HUV rings either with or without endothelium. However, under concurrent inhibition of ACE, NEP and APM, there was a higher potentiation of DAKD-elicited contractile responses compared with the effect observed with combined inhibition of ACE and APM. Moreover, when we evaluated contractile responses induced by Sar(0)-D-Phe(8)-des-Arg(9)-BK (a metabolically protected B(1) receptor agonist), no potentiating effect was observed under triple enzymatic inhibition. In conclusion, in the present study for the first time, we demonstrated in a capacitance vessel, HUV, that metallopeptidases ACE, NEP and APM represent a relevant functional inactivation pathway of DAKD.

Antimicrobial susceptibility of non-enterococcal intrinsic glycopeptide-resistant Gram-positive organisms.

Non-enterococcal Gram-positive bacteria that are intrinsically vancomycin-resistant have been infrequently isolated in association with serious infections. However, well-documented infections have lately been reported with increasing frequency. Because these organisms may be pathogens, we tested the MICs of 19 antimicrobial agents by the agar dilution method for predicting susceptibility. The activity of these antimicrobial agents was assessed against 28 strains (Lactobacillus rhamnosus, 6; Lactobacillus acidophilus, 1; Lactobacillus casei, 1; Lactobacillus fermentum, 2; Lactobacillus brevis, 1; Lactobacillus plantarum, 1; Weissella confusa, 2; Leuconostoc mesenteroides, 7; Leuconostoc lactis, 4; Pediococcus acidilactici, 2; Pediococcus pentosaceus, 1), isolated from clinical specimens in an Argentinian university hospital from 1997 to 2003. The MICs of penicillin for 67% of the Lactobacillus strains and 100% of the Leuconostoc spp. and Pediococcus spp. strains tested were in the 0.25-2 microg/mL range. Erythromycin was the most active antimicrobial overall. Multiresistance was observed in 2 strains (Lactobacillus rhamnosus, 1; Lactobacillus plantarum, 1).

Neutral endopeptidase up-regulation in isolated human umbilical artery: involvement in desensitization of bradykinin-induced vasoconstrictor effects.

Previous reports show that bradykinin B(2) receptors mediate contractile responses induced by bradykinin (BK) in human umbilical artery (HUA). However, although it has been reported that BK-induced responses can desensitize in several inflammatory models, the effects of prolonged in vitro incubation on BK-induced vasoconstriction in HUA have not been studied. In isolated HUA rings, BK-induced responses after a 5-h in vitro incubation showed a marked desensitization compared with responses at 2 h. Inhibition of either angiotensin-converting enzyme (ACE) or neutral endopeptidase (NEP), both BK-inactivating enzymes, failed to modify responses to BK at 2 h. After 5 h, ACE inhibition produced only a slight potentiation of BK-induced responses. In contrast, BK-induced vasoconstriction at 5 h was markedly potentiated by NEP inhibition. Moreover, NEP activity, measured by hydrolysis of its synthetic substrate (Z-Ala-Ala-Leu-p-nitroanilide), showed a 2.4-fold increase in 5-h incubated versus 2-h incubated tissues, which was completely reversed by cycloheximide (CHX) treatment. Furthermore, CHX significantly potentiated BK-induced responses, suggesting that NEP-mediated kininase activity increase at 5 h depends on de novo protein synthesis. In addition, under NEP inhibition, CHX treatment failed to produce an additional potentiation of BK-induced vasoconstriction. Still, NEP up-regulation was confirmed by Western blot, showing a 2.1-fold increase in immunoreactive NEP in 5-h incubated versus 2-h incubated HUA. In summary, the present study provides strong pharmacological evidence that NEP is up-regulated and plays a key role in desensitization of BK-induced vasoconstriction after prolonged in vitro incubation in HUA. Our results provide new insights into the possible mechanisms involved in BK-induced response desensitization during sustained inflammatory conditions.

In vitro antibacterial activity of the peptide PsVP-10 against Streptococcus mutans and Streptococcus sobrinus with and without glycocalyx.

The antibacterial activity of the peptide PsVP-10 obtained from Pseudomonas sp. R10 against Streptococcus mutans and Streptococcus sobrinus was investigated. One hundred and twenty strains of S. mutans and 120 strains of S. sobrinus with and without glycocalyx were isolated from saliva samples in trypticase-yeast-cysteine-sucrose-bacitracin (TYCSB) agar. Bacterial identification was made by polymerase chain reaction. Glycocalyx production was observed in modified TYCSB agar and confirmed with a modified version of the microplate adherence assay. The minimum inhibitory concentration (MIC) of PsVP-10 bacteriocin was determined by means of the agar dilution method, and the time of bacterial death was calculated by means of colony-forming unit counts. The MIC of the bacteriocin PsVP-10 for both bacterial species with and without glycocalyx was < 2 mg/L and the time of bacterial death was less than 240 s for all the studied bacterial strains. Thus, bacteriocin PsVP-10 could be an interesting possibility to combat these cariogenic bacterial species.

Antimicrobial activity of dalbavancin tested against Gram-positive clinical isolates from Latin American medical centres.

The activity of dalbavancin, a new semi-synthetic lipoglycopeptide antibiotic, was evaluated in comparison with other antibacterial agents against 1229 Gram-positive organisms collected from medical centres in Latin America. Dalbavancin was the most potent compound tested against isolates of Staphylococcus aureus (MIC(50), 0.06 mg/L) and coagulase-negative staphylococci (MIC(50), 0.03 mg/L), independently of methicillin susceptibility. Dalbavancin inhibited all Streptococcus pneumoniae isolates at /= 8 mg/L. Dalbavancin exhibited excellent activity against isolates of Corynebacterium spp. and Listeria spp. Dalbavancin may provide an important therapeutic option for Gram-positive infections, excluding those caused by enterococci with VanA-type resistance.

Further evidence on the anxiogenic-like effect of substance P evaluated in the elevated plus-maze in rats.

Substance P (SP) and its preferred NK1 receptor are widely expressed throughout the fear-processing pathways of the brain and its role in the modulation of experimental anxiety has been demonstrated. SP, like other peptides, are cleaved by peptidases in two fragments: C-terminal (SP 6-11) and N-terminal (SP 1-7) that could be responsible for its anxiogenic-like response. In this study we investigate the effects of i.c.v. micro-injections of SP free acid (SPfa), which is resistant to enzymatic cleavage, the influence of the pretreatment with peptidase inhibitors (PIs), thiorphan and/or phosphoramidon, as well as the effects of SP 6-11 and SP 1-7 and the participation of NK1 and NK2 receptors on their behavioral effects. Adult male Wistar rats were treated with 10 pmol solutions of SP 6-11, SP 1-7 or 1 and 10 pmol of SPfa and evaluated in the elevated plus maze (EPM) test. Other experimental groups received thiorphan 0.2 pmol, phosphoramidon 2 pmol or both PIs 30 min prior SP 1-11, 10 pmol i.c.v. The C-terminal fragment (SP 6-11, 10 pmol) and SPfa (1 pmol) promoted an anxiogenic-like profile of action similar to 10 pmol of SP 1-11, i.e., a decrease of entries and time spent on the open arms, whereas the N-terminal fragment (SP 1-7) was inactive at the EPM. The effect of SP 6-11 was inhibited by pretreatment (100 pmol) with NK1 (FK 888) and NK2 (SR 48968) antagonists. Moreover, both PIs enhanced the SP effect when used alone, but their combination produced an apparent reversion of anxiogenic-like effect produced by SP. Altogether, our results give further support to the SP role in the modulation of experimental anxiety in rats.

A low dose of angiotensin II increases inotropism through activation of reverse Na(+)/Ca(2+) exchange by endothelin release.

OBJECTIVE: This work was aimed to prove that release/formation of endogenous endothelin acting in an autocrine/paracrine fashion contributes to the increase in contractility promoted by a low dose of angiotensin II. METHODS: Isolated cat papillary muscles were used for force, pH(i), [Na(+)](i) and [Ca(2+)](i) measurements and isolated cat myocytes for patch-clamp experiments. RESULTS: In papillary muscles, 1.0 nmol/l angiotensin II increased force by 23+/-2% (n=4, P<0.05), [Na(+)](i) by 2.2+/-0.2 mmol/l (n=4, P<0.05), and peak (but not diastolic) Ca(2+) from 0.674+/-0.11 to 0.768+/-0.13 micromol/l (n=4, P<0.05), without affecting pH(i). Force and [Na(+)](i) increase were abolished by inhibition of the Na(+)/H(+) exchanger (NHE) with the inhibitor HOE642, blockade of endothelin receptors with the nonselective antagonist TAK044 and by inhibition of the endothelin-converting enzyme with phosphoramidon. Force but not [Na(+)](i) increase was abolished by inhibition of reverse Na(+)/Ca(2+) exchange (NCX) with the inhibitor KB-R7943. Similar increase in force (21+/-2%, n=4, P<0.05) and in [Na(+)](i) (2.4+/-0.4 mmol/l, n=4, P<0.05) that were also suppressed by TAK044 and HOE642 were induced by exogenous 5.0 nmol/l endothelin-1. KB-R7943 reverted the endothelin-1 effect on force but not on [Na(+)](i). In isolated myocytes, exogenous endothelin-1 dose-dependently increased the NCX current and shifted the NCX reversal potential (E(NCX)) to a more negative value (DeltaE(NCX): -10+/-3 and -17+/-5 mV, with 1 and 10 nmol/l endothelin-1, respectively, n=12). The latter effect was prevented by HOE642. CONCLUSION: Taken together, the results indicate that a low dose of angiotensin II induces release of endothelin, which, in autocrine/paracrine fashion activates the Na(+)/H(+) exchanger, increases [Na(+)](i) and changes E(NCX), promoting the influx of Ca(2+) that leads to a positive inotropic effect (PIE).