Hyaluronidase increases the duration of mepivacaine in inferior alveolar nerve blocks

Purpose: To evaluate the duration of the effect of mepivacaine when hyaluronidase is injected immediately prior to the end of pulpal anesthesia. Patients and Methods: Forty bilateral, symmetrical third molar surgeries were performed in 20 healthy patients. Inferior alveolar nerve block was induced using 2.8 mL 2% mepivacaine with epinephrine. Hyaluronidase (75 turbidity-reducing units) or a placebo was injected 40 minutes after the beginning of pulpar anesthesia (randomized and double-blind trial). The duration of effect in the pulpal and gingival tissues was evaluated by response to painful electrical stimuli applied to the Adjacent premolar, and by mechanical stimuli (pin prick) to the vestibular gingiva, respectively. Results: in both tissues, the duration of anesthetic effect with hyaluronidase was longer (P <.01) than with the placebo. Conclusion: Hyaluronidase increases the duration of mepivacaine in inferior alveolar nerve blocks. (c) 2008 American Association of Oral and Maxillofacial Surgeons.

Leishmania amazonensis: Biosynthesis of polyprenols of 9 isoprene units by amastigotes

The isoprenoid metabolic pathway in protozoa of the Leishmania genus exhibits distinctive characteristics. These parasites, as well as other members of the Trypanosomatidae family, synthesize ergosterol, instead of cholesterol, as the main membrane sterol lipid. Leishmania has been shown to utilize leucine, instead of acetate as the main precursor for sterol biosynthesis. While mammalian dolichols are molecules containing 15-23 isoprene units, Leishmania amazonensis promastigotes synthesize dolichol of 11 and 12 units. In this paper, we show that the intracellular stages of L. amazonensis, amastigotes, synthesize mainly polyprenols of 9 isoprene units, instead of dolichol. (c) 2007 Elsevier Inc. All rights reserved.

Involvement of proteinase-activated receptors 1 and 2 in spreading and phagocytosis by murine adherent peritoneal cells: Modulation by the C-terminal of S100A9 protein

Proteinase-activated receptors (PAR) are widely recognized for their modulatory properties in inflammatory and immune responses; however, their direct role on phagocyte effector functions remains unknown. S100A9, a protein secreted during inflammatory responses, deactivates activated peritoneal macrophages, and its C-terminal portion inhibits spreading and phagocytosis of adherent peritoneal cells. Herein, the effect of PAR1 and PAR2 agonists was investigated on spreading and phagocytosis by adherent peritoneal cells, as well as the ability of murine C-terminal of S100A9 peptide (mS100A9p) to modulate this effect. Adherent peritoneal cells obtained from mouse abdominal cavity were incubated with PAR1 and PAR2 agonists and spreading and phagocytosis of Candida albicans particles were evaluated. PAR1 agonists increased both the spreading and the phagocytic activity, but PAR2 agonists only increased the spreading index. mS100A9p reverted both the increased spreading and phagocytosis induced by PAR1 agonists, but no interference in the increased spreading induced by PAR2 agonists was noticed. The shorter homologue peptide to the C-terminal of mS100A9p, corresponding to the H(92)-E(97) region, also reverted the increased spreading and phagocytosis induced by PAR1 agonists. These findings show that proteinase-activated receptors have an important role for spreading and phagocytosis of adherent peritoneal cells, and that the pepticle corresponding to the C-terminal of S100A9 protein is a remarkable candidate for use as a novel compound to modulate PAR1 function. (C) 2009 Elsevier B.V. All rights reserved.

Susceptibility of Staphylococcus aureus to porphyrin-mediated photodynamic antimicrobial chemotherapy: an in vitro study

The ability of Staphylococcus aureus to develop multidrug resistance is well documented, and the antibiotic resistance showed by an increasing number of bacteria has shown the need for alternative therapies to treat infections, photodynamic therapy (PDT) being a potential candidate. The aim of this study was to determine the effect of photodynamic therapy as a light-based bactericidal modality to eliminate Staphylococcus aureus. The study investigated a technique based on a combination of light and a photosensitizer that is capable of producing oxidative species to induce a cytotoxic effect. A Staphylococcus aureus suspension was exposed to a light emitting diode (LED) emitting at 628 nm, 14.6 mW/cm(2), and energy density of 20J/cm(2), 40J/cm(2), or 60 J/cm(2) in the presence of different porphyrin concentrations (PhotogemA (R)). Three drug concentrations were employed: 12 mu l/ml, 25 mu l/ml, and 50 mu l/ml. The treatment response was evaluated by the number of bacterial colony forming units (CFU) after light exposure. The results indicated that exposure to 60 J/cm(2) eliminated 100% (10 log(10) scales) of bacteria, on average. The best PDT response rate to eliminate Staphylococcus aureus was achieved with exposure to LED light in combination with the photosensitizer at concentrations ranging from 25 mu l/ml to 50 mu l/ml. These data suggest that PDT has the potential to eliminate Staphylococcus aureus in suspension and indicates the necessary drug concentration and light fluency.

Lower and Upper Neoproterozoic magmatic records in Itaiacoca Belt (Parana-Brazil): Zircon ages and lithostratigraphy studies

The Itaiacoca Belt is a sequence of metavolcanic and metasedimentary rocks that crop out east of Parana and southeast of Sao Paulo states, in southern Brazil. This geologic-geochronologic study supports division of the Itaiacoca Belt into two major lithologic sequences. The older is a carbonate platform sequence (dolomitic meta-limestones/metamarls/calc-phyllites/ carbonate phyllites) with minimum deposition ages related to the end of the Mesoproterozoic/beginning of the Neoproterozoic (1030-908 Ma:U-Pb, zircon of metabasic rocks). The younger sequence contains mainly clastics deposits (meta-arkoses/metavolcanics/metaconglomerates/metapelites) with deposition ages related to the Neoproterozoic (645-628 Ma:U-Pb,zircon of metavolcanic rocks). These ages are quite close to K-Ar ages (fine fraction) of the 628-610 Ma interval, associated with metamorphism and cooling of the Itaiacoca Belt. The contact between the dolomitic meta-limestones and meta-arkoses is marked by intense stretching and high-angle foliation, suggesting that the discontinuity between these associations resulted from shearing. It is proposed here that the term Itaiacoca Sequence, should represent the dolomitic meta-limestones, and the term Abapa Sequence represents the meta-arkoses/metavolcanics/phyllites. in a major tectonic context, these periods are related to the break-up of Rodinia Supercontinent (1030-908 Ma) and the amalgamation of the Gondwana Supercontinent (645-628 Ma). (C) 2008 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved.

Subsite substrate specificity of midgut insect chymotrypsins

Insect chymotrypsins are distinctively sensitive to plant protein inhibitors, suggesting that they differ in subsite architecture and hence in substrate specificities. Purified digestive chymotrypsins from insects of three different orders were assayed with internally quenched fluorescent oligopeptides with three different amino acids at P1 (Tyr, Phe, and Leu) and 13 amino acid replacements in positions P1`, P2, and P3. The binding energy (Delta G(s), calculated from Km values) and the activation energy (Delta G(T)(double dagger), determined from k(cat)/K-m values) were calculated. The hydrophobicities of each subsite were calculated from the efficiency of hydrolysis of the different amino acid replacements at that subsite. The results showed that except for S1, the other subsites (S2, S3, and S1`) vary among chymotrypsins. This result contrasts with insect trypsin data that revealed a trend along evolution, putatively associated with resistance to plant inhibitors. In spite of those differences, the data suggested that in lepidopteran chymotrypsins S2 and S1` bind the substrate ground state, whereas only S1` binds the transition state, supporting aspects of the present accepted mechanism of catalysis. 2008 Elsevier Ltd. All rights reserved.

Implementing stepwise solvent elution in sequential injection chromatography for fluorimetric determination of intracellular free amino acids in the microalgae Tetraselmis gracilis

The concept of sequential injection chromatography (SIC) was exploited to automate the fluorimetric determination of amino acids after pre-column derivatization with ophthaldialdehyde (OPA) in presence of 2-mercaptoethanol (2MCE) using a reverse phase monolithic C(18) stationary phase. The method is low-priced and based on five steps of isocratic elutions. The first step employs the mixture methanol: tetrahydrofuran: 10 mmol L(-1) phosphate buffer (pH 7.2) at the volumetric ratio of 8:1:91; the other steps use methanol: 10 mmol L-1 phosphate buffer (pH 7.2) at volumetric ratios of 20:80, 35:65, SO:SO and 65:35. At a flow rate of 10 mu L s(-1) a 25 mm long-column was able to separate aspartic acid (Asp), glutamic acid (Glu), asparagine (Asn), serine (Ser), glutamine (Gln), glycine (Gly), threonine (Thr), citruline (Ctr), arginine (Arg), alanine (Ala), tyrosine (Tyr), phenylalanine (Phe), ornithine (Orn) and lysine (Lys) with resolution >1.2 as well as methionine (Met) and valine (Val) with resolution of 0.6. Under these conditions isoleucine (Ile) and leucine (Leu) co-eluted. The entire cycle of amino acids derivatization, chromatographic separation and column conditioning at the end of separation lasted 25 min. At a flow rate of 40 mu L s(-1) such time was reduced to 10 min at the cost of resolution worsening for the pairs Ctr/Arg and Orn/Lys. The detection limits varied from 0.092 mu mol L(-1) for Tyr to 0.51 mu mol L(-1) for Orn. The method was successfully applied to the determination of intracellular free amino acids in the green alga Tetraselmis gracilis during a period of seven days of cultivation. Samples spiked with known amounts of amino acids resulted in recoveries between 94 and 112%. (C) 2008 Elsevier B.V. All rights reserved.