The effect of glycerol on signal supression during electrospray ionization analysis of proteins

The effect of salts, detergents and chaotropic agents on mass spectrometric analysis are relatively well understood, mainly due to their actions decreasing the performance of ESI interface in mass spectrometric analysis. However, there are few studies in the literature characterizing the effect of protein stabilization by glycerol, followed in some circumstances by the suppression of protein signal when ESI interface is used. The aim of the present research was to investigate in details the mass spectrometric behavior of some proteins in presence of high levels of glycerol during ESI-MS analysis. Thus, horse heart myoglobin and chicken ovalbumin were used as standard proteins. It was demonstrated that the presence of 1% (v/v) glycerol suppressed the signal of these proteins during the ESI-MS analysis, even when the sample nozzle potential was scanned from 28 to 80 V. However, when the glycerol concentration was decreased to 0.5% (v/v) and the sample cone voltage adjusted to 50 V, a perfect envelope of peaks was observed, allowing the spectrum deconvolution and the molecular mass determination with mass accuracy lower than 0.01% in each situation. A molecular explanation for this suppressive effect and for the analytical overcoming of this difficult is proposed.

Lack of inhibitory effect of zinc on prolactin secretion induced by cimetidine

The dopaminergic, serotoninergic and GABA-ergic systems are closely involved in PRL secretion, as well as thyrotropin-releasing hormone. There is some evidence that zinc interacts with some of these neuroamines and neuropeptides. The histamine H2-receptor cimetidine stimulates PRL secretion rapidly following an intravenous injection in man. In this sense, we investigated probable inhibitory effect of zinc on prolactin secretion following cimetidine injection (300 mg). Therefore, we studied five healthy adult men, before and after oral zinc administration (25 mg elemental zinc) during three consecutive months. The results did not demonstrate any inhibitory effect of zinc on prolactin secretion. So, we originally concluded that zinc did not interact with dopamine, serotonine, gamma-aminobutyric acid and the thyrotropin-releasing hormone in humans. In addition, the intravenous administration of cimetidine did not change the serum zinc profile. © 2005 Dustri-Vertag Dr. K. Feistle.

Inhibitory effect of deferoxamine on Paracoccidioides brasiliensis survival in human monocytes: Reversal by holotransferrin not by apotransferrin

The mechanisms used by Paracoccidioides brasiliensis to survive into phagocytic cells are not clear. Cellular iron metabolism is of critical importance to the growth of several intracellular pathogens whose capacity to multiply in mononuclear phagocytes is dependent on the availability of intracellular iron. Thus, the objective of this paper was to investigate the role of intracellular iron in regulating the capacity of P. brasiliensis yeast cells to survive within human monocytes. Treatment of monocytes with deferoxamine, an iron chelator, suppressed the survival of yeasts in a concentration-dependent manner. The effect of deferoxamine was reversed by iron-saturated transferrin (holotransferrin) but not by nonsaturated transferrin (apotransferrin). These results strongly suggest that P. brasiliensis survival in human monocytes is iron dependent.

Dynamic and isometric protocols of knee extension: Effect of fatigue on the EMG signal

The objective of this study was to analyze the electromyographic (EMG) signal behavior of rectus femoris (RF), vastus medialis (VM), vastus lateralis (VL) and biceps femoris (caput longum) (BFCL) from nine women during fatiguing dynamic and isometric knee extensions tests and to determine their EMGFT (Electromyographic Fatigue Threshold). Surface electrodes, biological signal acquisition module, analogical-digital converter board and specific software were used. The RMS (Root Mean Square) values obtained from concentric phase (80 to 30 degrees) of the dynamic knee extension andfrom isometric contraction were correlated with time on each load by linear regression analysis. The respective slopes were correlated with the correspondent load to determine the EMGFT. Force (Kgf) and median frequency - MF (Hz) obtained during MIVC (Maximal Isometric Voluntary Contraction) performed before and after the fatiguing tests were calculated in Matlab environment. The results demonstrated that the endurance time decreases with higher loads the EMG amplitude increase with time and was greater at higher loads, between muscles in dynamic exercise the RF and VL showed higher slopes, and in isometric exercise the VL showed the same behavior The EMGFT values were similar in both exercises; the force values predominantly decreased after fatiguing tests; however the MF only decreased after some loads. The protocols proposed allowed standardizing protocols at least to induce the fatigue process and to determine the EMGFT as an endurance indicative, which may be used to evaluate the effectiveness of rehabilitative or training interventions indicated to reduce muscle weakness and fatigue.

Effect of prostaglandins on the production of H2O2 and cytokines that modulate the fungicidal activity of human monocytes against Paracoccidioides brasiliensis

Human monocytes lack fungicidal activity against high virulent strains of Paracoccidioides brasiliensis, the etiological agent of paracoccidioidomycosis, even after IFN-γ activation. However, monocytes treated with indomethacin (INDO) or INDO plus IFN-γ effectively killed this fungus, suggesting an inhibitory role of prostaglandins in this process. Thus, the purpose of this work was to test if this regulatory effect of prostaglandin was associated with alterations on H2O2 production and/or on modulatory cytokines levels, such as TNF-α, IL-10, and IL-6. Peripheral blood monocytes obtained from 10 healthy donors were incubated for 18 hours in the presence or absence of IFN-γ, INDO, or IFN-γ plus INDO, and further challenged with a high virulent strain of P. brasiliensis (Pb18) for 4 hours. Then, the monocytes cultures were evaluated for H2O2 release and fungicidal activity calculated by counting the colony forming units after plating. Moreover, on supernatants of the same cultures, TNF-α, IL-10, IL-6, and PGE2 concentrations were evaluated by ELISA. Monocytes treated with INDO or INDO plus IFN-γ presented higher fungicidal activity associated with the release of higher levels of H2O2 and TNF-α, but lesser levels of PGE2, when compared to nontreated cells. However, the levels of IL-10 and IL-6 were similar between treated and nontreated cells. The results suggest that human monocytes when challenged with high virulent strains of P. brasiliensis produce prostaglandins that inhibit the fungicidal activity of these cells by reducing H2O2 and TNF-α levels.

Effect of disinfectants on the hardness and roughness of reline acrylic resins

Purpose: Potential effects on hardness and roughness of a necessary and effective disinfecting regimen (1% sodium hypocholorite and 4% chlorhexidine) were investigated for two hard chairside reline resins versus a heat-polymerizing denture base acrylic resin. Materials and Methods: Two standard hard chairside reliners (Kooliner and Duraliner II), one heat-treated chairside reliner (Duraliner II +10 minutes in water at 55°C), and one standard denture base material (Lucitone 550) were exposed to two disinfecting solutions (1% sodium hypochlorite; 4% chlorhexidine gluconate), and tested for two surface properties [Vickers hardness number (VHN, kg/mm2); Roughness (Ra, μm)] for different times and conditions (1 hour after production, after 48 hours at 37 ± 2°C in water, after two disinfection cycles, after 7 days in disinfection solutions, after 7 days in water only). For each experimental condition, eight specimens were made from each material. Data were analyzed by analysis of variance followed by Tukey's test, and Student's t-test (p= 0.05). Results: For Kooliner (from 6.2 ± 0.3 to 6.5 ± 0.5 VHN) and Lucitone 550 (from 16.5 ± 0.4 to 18.4 ± 1.7 VHN), no significant changes in hardness were observed either after the disinfection or after 7 days of immersion, regardless of the disinfectant solution used. For Duraliner II (from 4.0 ± 0.1 to 4.2 ± 0.1 VHN), with and without heat treatment, a small but significant increase in hardness was observed for the specimens immersed in the disinfectant solutions for 7 days (from 4.3 ± 0.2 to 4.8 ± 0.5 VHN). All materials showed no significant change in roughness (Kooliner: from 0.13 ± 0.05 to 0.48 ± 0.24 μm; Duraliner II, with and without heat treatment: from 0.15 ± 0.04 to 0.29 ± 0.07 μm; Lucitone 550: from 0.44 ± 0.19 to 0.49 ± 0.15 μm) after disinfection and after storage in water for 7 days. Conclusions: The disinfectant solutions, 1% sodium hypochlorite and 4% chlorhexidine gluconate, caused no apparent damage on hardness and roughness of the materials evaluated. Copyright © 2006 by The American College of Prosthodontists.

The effect of pH on horseradish peroxidase-catalyzed oxidation of melatonin: Production of N1-acetyl-N2-formyl-5- methoxykynuramine versus radical-mediated degradation

There is a growing body of evidence that melatonin and its oxidation product, N1-acetyl-N2-formyl-5-methoxykynuramine (AFMK), have anti-inflammatory properties. From a nutritional point of view, the discovery of melatonin in plant tissues emphasizes the importance of its relationship with plant peroxidases. Here we found that the pH of the reaction mixture has a profound influence in the reaction rate and products distribution when melatonin is oxidized by the plant enzyme horseradish peroxidase. At pH 5.5, 1 mm of melatonin was almost completely oxidized within 2 min, whereas only about 3% was consumed at pH 7.4. However, the relative yield of AFMK was higher in physiological pH. Radical-mediated oxidation products, including 2-hydroxymelatonin, a dimer of 2-hydroxymelatonin and O-demethylated dimer of melatonin account for the fast consumption of melatonin at pH 5.5. The higher production of AFMK at pH 7.4 was explained by the involvement of compound III of peroxidases as evidenced by spectral studies. On the other hand, the fast oxidative degradation at pH 5.5 was explained by the classic peroxidase cycle. © 2007 The Authors.

Effect of erythromycin on motility and gastric emptying in dogs, by AC Biosusceptometry

We employed ACB to characterize Gastric Emptying Time (GET - T1/2) and Gastric Activity Contraction (GAC) in dogs after erythromycin administration. An erythromycin dose of 50 mg was infused, after 24 h of fasting. Without erythromycin administration, ACB recorded GET of 157.5 ± 13.6 min (mean ± SD) and GAC of 4.4 ± 0.5 cpm (cycles per minute). After erythromycin administration was measured a GET of 84.2 ± 19.7 min. GAC was measured before, during and after erythromycin administration and results were, respectively, 4.4 ± 0.5, 4.9 ± 0.6 and 4.2 ± 0.3 cpm. Erythromycin produced efficient prokinetic action in gastric emptying and increased gastric motility in dogs. © 2007 Elsevier B.V. All rights reserved.

The effect of age on hematological and serum biochemical values on juvenile ring-necked pheasants (Phasianus colchicus)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

The effect of age on the blood proteinogram of Chinese goose (Anser cygnoides)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effect of occlusion on joint sounds in asymptomatic individuals.

Occlusion is a predisposing factor for Temporomandibular Dysfunctions (TMD) of the joint, whose first sign and/or symptom is usually joint sound. To verify the effect of occlusion on joint sounds, temporomandibular joints (TMJ) were analyzed in 78 asymptomatic individuals with various dental conditions. Electrosonography was used to determine the intensity of the vibration in the temporomandibular joint (TMJ) on opening and closing the mouth. Transducers (piezoelectric accelerometer) were placed on the right and left joints. Results were tabled and analyzed using the Kruskal-Wallis test (a=0.05). It was concluded that TMJ vibration in partly edentulous individuals from Kennedy classes I, II and III is statistically higher than in dentate and fully edentulous subjects.

Effect of radiotherapy on the radiopacity and flexural strength of a composite resin.

The aim of this study was to evaluate the effect of radiotherapy on the radiopacity and flexural strength of composite resin. Forty Z250 composite resin specimens were polymerized using a halogen light-curing unit and divided into 5 groups, in accordance with the radiotherapy dose: G1- without irradiation, G2- 30 Gy, G3- 40 Gy, G4- 50 Gy and GS- 60 Gy Digital images were obtained using a GE 100 X-ray. Radiopacity values were obtained with the Digora digital imaging system and the flexural strength was evaluated with an EMIC universal testing machine. Data were submitted to ANOVA and Tukey 's test. G1 presented the highest radiopacity value, followed by G3, G5, G4 and G2. For flexural strength, G1 presented the lowest value, followed by G2, G5, G3 and G4. Differences were no significant (p>0.05). The commonly used dosage of radiotherapy treatment, did not cause alteration in the radiopacity and flexural strength of resin-based composites.

Effect of drying on the reproducibility of DIAGNOdent to detect caries-like lesions

The aim of this study was to verify the drying effect on the reproducibility of DIAGNOdent (Dd) devices to detect caries-like lesions. Three areas were created in each of the 34 bovine incisors: sound (S), demineralized (DE) and remineralized (RE). One examiner measured each area with two Dd devices (denominated X and Y), twice under humid, and twice under dry condition. Intra-rater agreement according each device and inter-device agreement were estimated by kappa statistics (κ). Intra-rater agreement for device Y was substantial under humid (κ DE=0.68 and κ RE+S=0.68) and dry condition (κ DE=0.64 and κ RE+S=0.67). For device X, it was substantial under humid condition (κ DE=0.57 and κ RE+S=0.49), and it was almost perfect after air drying (κ DE=1.0 and κRE+S=1.0). Inter-device agreement was slight (κ =0.17) under humid condition, and it was substantial under dry condition (κ =0.62). As reproducibility increased under dry condition, drying is advised to detect caries-like lesions on free smooth surfaces when different devices are used.

Effect of fungicides on the mite fauna of prunus persica L. cultivars in Presidente Prudente, SP, Brazil

The objective of this study was to characterize the diversity of phytophagous and predatory mites on peach cultivars either with or without fungicide treatment, in the city of Presidente Prudente, State of São Paulo, Brazil. In order to evaluate the effect of fungicides, leaf samples were colleted at random from treated and untreated plants of the Tropical, Aurora 1 and Aurora 2 cultivars, from June 2004 to February 2006. From the results obtained it can be concluded that: plants with or without treatment showed high populations of predatory mites, indicating that the treatments were innocuous on the mite populations. A diversified composition of the mite community was observed. The Phytoseiidae family had the highest richness in numbers and species of mites. Euseius citrifolius and E. concordis were the most abundant species. Plants with or without treatment had high abundances of predatory mites, with a predominance of E. citrifolius.