Synergistic effect of hydralazine associated with triazoles on Candida spp. in planktonic cells.

Objective: To evaluate the antifungal activity of hydralazine hydrochloride alone and in synergy with azoles against Candida spp. and the action mechanism. Methods: We used broth microdilution assays to determine the MIC, checkerboard assays to investigate synergism, and flow cytometry and molecular docking tests to ascertain action mechanism. Results: Hydralazine alone had antifungal activity in the range of 16-128 µg/ml and synergistic effect with itraconazole versus 100% of the fungal isolates, while there was synergy with fluconazole against 11.11% of the isolates. There was molecular interaction with the receptors exo-B(1,3)-glucanase and CYP51, causing reduced cell viability and DNA damage. Conclusion: Hydralazine is synergistic with itraconazole and triggers cell death of Candida spp. at low concentrations, demonstrating antifungal potential.

Antifungal activity of dexamethasone against fluconazole-resistant Candida albicans and its activity against biofilms.

Objective: The present study investigated the antifungal action of dexamethasone disodium phosphate (Dex). Methodology: Susceptibility testing was performed using the Clinical & Laboratory Standards Institute protocol; M27-A3, checkerboard test and biofilm were evaluated with two isolates of Candida albicans, hyphal production test, molecular docking analysis and flow cytometry analysis. Result: Dex and fluconazole (FLC) together had a synergistic effect. Mature biofilm was reduced when treated with Dex alone or in combination. Dex and FLC promoted a decrease in the production of hyphae and changes in the level of mitochondrial depolarization, increased generation of reactive oxygen species, loss of membrane integrity, increased phosphatidylserine externalization and molecular docking; there was interaction with ALS3 and SAP5 targets. Conclusion: Dex showed antifungal activity against FLC-resistant C. albicans strains.

This study aimed to evaluate the antifungal action of dexamethasone against FLC-resistant C. albicans strains.

Synergistic activity of dobutamine combined with azoles and its mechanism of action against strains of Candida glabrata.

Aims: To evaluate the antifungal effect of dobutamine against Candida glabrata as well as its synergism with azoles and its action on biofilm. Methods: The M27-A3 protocol and flow cytometry were used for elucidation of the possible mechanism of action. Results: The tested isolates presented MICs ranging from 2 to 32 µg/ml for dobutamine, with fungistatic effect. A total of 82% of the strains showed synergism with fluconazole, with 90% showing synergism with itraconazole. The effect on biofilm formation was nonsignificant. Cytometry tests showed that dobutamine induced mitochondrial depolarization. Conclusion: Dobutamine has an antifungal effect on strains of C. glabrata and synergistic activity with azoles. This effect is probably mediated by increased oxidative damage to the membrane.

Synergistic activity of diclofenac sodium with oxacillin against planktonic cells and biofilm of methicillin-resistant Staphylococcus aureus strains.

Aim: To evaluate the activity of diclofenac sodium and synergism with oxacillin against clinical strains of SARM in plactonic cells, antibiofilm and biofilm. Materials & methods: Synergism activity was assessed using the fractional inhibitory concentration index and its possible mechanism of action by flow cytometry. Results: The synergistic activity of diclofenac sodium with oxacillin was observed against plactonic cells, antibiofilm and in biofilm formed from clinical methicillin-resistant Staphylococcus aureus strains. Conclusion: This combination caused damage to the integrity of the membrane and ruptures in the DNA of the cells, leading to apoptosis.

Synergistic anticandidal activity of etomidate and azoles against clinical fluconazole-resistant Candida isolates.

Aim: The purpose of this study was to evaluate the effect of etomidate alone and in combination with azoles on resistant strains of Candida spp. in both planktonic cells and biofilms. Materials & methods: The antifungal activity of etomidate was assessed by the broth microdilution test; flow cytometric procedures to measure fungal viability, mitochondrial transmembrane potential, free radical generation and cell death; as well detection of DNA damage using the comet assay. The interaction between etomidate and antifungal drugs (itraconazole and fluconazole) was evaluated by the checkerboard assay. Results: Etomidate showed antifungal activity against resistant strains of Candida spp. in planktonic cells and biofilms. Etomidate also presented synergism with fluconazole and itraconazole in planktonic cells and biofilms. Conclusion: Etomidate showed antifungal activity against Candida spp., indicating that it is a possible therapeutic alternative.

Inhibitory effects of modafinil on emotional memory in mice.

Modafinil (MOD), a psychostimulant used to treat narcolepsy, excessive daytime sleepiness, and sleepiness due to obstructive sleep apnea, appears to promote a possible facilitatory effect on cognitive function. In the present study, we investigated the effects of the acute administration of MOD on the different steps of emotional memory formation and usage (acquisition, consolidation and retrieval) as well as the possible participation of the state-dependency phenomenon on the cognitive effects of this compound. Mice were acutely treated with 32, 64 or 128 mg/kg MOD before training or testing or immediately after training and were subjected to the plus-maze discriminative avoidance task. The results showed that although pre-training MOD administration did not exert any effects on learning, the doses of 32 or 64 mg/kg induced emotional memory deficits during testing. Still, the post-training acute administration of the higher doses of MOD (64 and 128 mg/kg) impaired associative memory consolidation. When the drug was administered pre-test, only the 32 mg/kg dose impaired the task retrieval. Importantly, the cognitive impairing effects induced by 32 mg/kg MOD were not related to the phenomenon of state-dependency. In all, our findings provide pre-clinical evidence of potential emotional memory amnesia induced by MOD. This article is part of a Special Issue entitled 'Cognitive Enhancers'.

Sleep deprivation impairs emotional memory retrieval in mice: influence of sex.

The deleterious effects of paradoxical sleep deprivation on memory processes are well documented. However, non-selective sleep deprivation occurs more commonly in modern society and thus represents a better translational model. We have recently reported that acute total sleep deprivation (TSD) for 6 h immediately before testing impaired performance of male mice in the plus-maze discriminative avoidance task (PM-DAT) and in the passive avoidance task (PAT). In order to extend these findings to females, we examined the effect of (pre-test) TSD on the retrieval of different memory tasks in both male and female mice. Animals were tested using 3 distinct memory models: 1) conditioning fear context (CFC), 2) PAT and 3) PM-DAT. In all experiments, animals were totally sleep-deprived by the gentle interference method for 6h immediately before being tested. In the CFC task and the PAT, TSD induced memory impairment regardless of sex. In PM-DAT, the memory impairing effects of TSD were greater in females. Collectively, our results confirm the impairing effect of TSD on emotional memory retrieval and demonstrate that it can be higher in female mice depending on the memory task evaluated.

Addictive potential of modafinil and cross-sensitization with cocaine: a pre-clinical study.

Repeated or even a single exposure to drugs of abuse can lead to persistent locomotor sensitization, which is the result of an abundance of neuroplastic changes occurring within the circuitry involved in motivational behavior and is thought to play a key role in certain aspects of drug addiction. There is substantial controversy about the addictive potential of modafinil, a wake-promoting drug used to treat narcolepsy that is increasingly being used as a cognitive enhancer and has been proposed as a pharmacotherapy for cocaine dependence. Male mice were used to investigate the ability of modafinil to induce locomotor sensitization after repeated or single administration in mice. Bidirectional cross-sensitization with cocaine and modafinil-induced conditioned place preference were also evaluated. Both repeated and single exposure to moderate and high doses of modafinil produced a pronounced locomotor sensitization that cross-sensitized in a bidirectional way with cocaine. Remarkably, when cocaine and modafinil were repeatedly administered sequentially, their behavioral sensitization was additive. Supporting these behavioral sensitization data, modafinil produced a pronounced conditioned place preference in the mouse. Taken together, the present findings provide pre-clinical evidence for the addictive potential of modafinil. Our data also strongly suggest that similar neural substrates are involved in the psychomotor/rewarding effects of modafinil and cocaine.

Effects of sleep deprivation on memory in mice: role of state-dependent learning.

STUDY OBJECTIVES: A considerable amount of experimental evidence suggests that sleep plays a critical role in learning/memory processes. In addition to paradoxical sleep, slow wave sleep is also reported to be involved in the consolidation process of memories. Additionally, sleep deprivation can induce other behavioral modifications, such as emotionality and alternations in locomotor activity in rodents. These sleep deprivation-induced alterations in the behavioral state of animals could produce state-dependent learning and contribute, at least in part, to the amnestic effects of sleep deprivation. The aim of the present study was to examine the participation of state-dependent learning during memory impairment induced by either paradoxical sleep deprivation (PSD) or total sleep deprivation (TSD) in mice submitted to the plus-maze discriminative avoidance or to the passive avoidance task. DESIGN: Paradoxical sleep deprivation (by the multiple platform method) and total sleep deprivation (by the gentle handling method) were applied to animals before training and/or testing. CONCLUSIONS: Whereas pre-training or pre-test PSD impaired retrieval in both memory models, pre-training plus pre-test PSD counteracted this impairment. For TSD, pre-training, pre-test, and pre-training plus pre-test TSD impaired retrieval in both models. Our data demonstrate that PSD- (but not TSD-) memory deficits are critically related to state-dependent learning.

Hepatitis B virus genotypes circulating in Brazil: molecular characterization of genotype F isolates.

BACKGROUND: Hepatitis B virus (HBV) isolates have been classified in eight genotypes, A to H, which exhibit distinct geographical distributions. Genotypes A, D and F are predominant in Brazil, a country formed by a miscegenated population, where the proportion of individuals from Caucasian, Amerindian and African origins varies by region. Genotype F, which is the most divergent, is considered indigenous to the Americas. A systematic molecular characterization of HBV isolates from different parts of the world would be invaluable in establishing HBV evolutionary origins and dispersion patterns. A large-scale study is needed to map the region-by-region distribution of the HBV genotypes in Brazil. RESULTS: Genotyping by PCR-RFLP of 303 HBV isolates from HBsAg-positive blood donors showed that at least two of the three genotypes, A, D, and F, co-circulate in each of the five geographic regions of Brazil. No other genotypes were identified. Overall, genotype A was most prevalent (48.5%), and most of these isolates were classified as subgenotype A1 (138/153; 90.2%). Genotype D was the most common genotype in the South (84.2%) and Central (47.6%) regions. The prevalence of genotype F was low (13%) countrywide. Nucleotide sequencing of the S gene and a phylogenetic analysis of 32 HBV genotype F isolates showed that a great majority (28/32; 87.5%) belonged to subgenotype F2, cluster II. The deduced serotype of 31 of 32 F isolates was adw4. The remaining isolate showed a leucine-to-isoleucine substitution at position 127. CONCLUSION: The presence of genotypes A, D and F, and the absence of other genotypes in a large cohort of HBV infected individuals may reflect the ethnic origins of the Brazilian population. The high prevalence of isolates from subgenotype A1 (of African origin) indicates that the African influx during the colonial slavery period had a major impact on the circulation of HBV genotype A currently found in Brazil. Although most genotype F isolates belonged to cluster II, the presence of some isolates belonging to clusters I (subgroup Ib) and IV suggests the existence of two or more founder viral populations of genotype F in Brazil.

Adding ketamine to morphine for patient-controlled analgesia after thoracic surgery: influence on morphine consumption, respiratory function, and nocturnal desaturation.

BACKGROUND: I.V. patient-controlled analgesia (PCA) with morphine is often used for postoperative analgesia after thoracic surgery, but the required doses may increase postoperative respiratory disorders. Adjunction of ketamine could reduce both doses and related respiratory side-effects. METHODS: The main objective of this prospective, randomized double-blinded study was to evaluate the influence of adding ketamine to PCA on morphine consumption and postoperative respiratory disorders. Consecutive patients undergoing lobectomy (n = 50) were randomly assigned to receive, during the postoperative period, either i.v. morphine 1 mg ml(-1) or morphine with ketamine 1 mg ml(-1) for each. Morphine consumption was evaluated by cumulative doses every 12 h for the three postoperative days. Postoperative respiratory disorders were assessed by spirometric evaluation and recording of nocturnal desaturation. RESULTS: The adjunction of ketamine resulted in a significant reduction in cumulative morphine consumption as early as the 36th postoperative hour [43 (SD 18) vs 32 (14) mg, P = 0.03] with a similar visual analogue scale. In the morphine group, the percentage of time with desaturation < 90% was higher during the three nights [1.80 (0.21-6.37) vs 0.02 (0-0.13), P < 0.001; 2.15 (0.35-8.65) vs 0.50 (0.01-1.30), P = 0.02; 2.46 (0.57-5.51) vs 0.55 (0.21-1.00), P = 0.02]. The decrease in forced expiratory volume in 1 s was less marked in the ketamine group at the first postoperative day [1.04 (0.68-1.22) litre vs 1.21 (1.10-0.70) litre, P = 0.039]. CONCLUSIONS: Adding small doses of ketamine to morphine in PCA devices decreases the morphine consumption and may improve respiratory disorders after thoracic surgery.

[Influence of the analgesic strategy on the respiratory function after thoracic surgery for lobectomy]. / Influence de la stratégie analgésique sur la fonction respiratoire après chirurgie thoracique pour lobectomie.

OBJECTIVE: To compare the influence of thoracic epidural analgesia (TEA) with intravenous patient-controlled analgesia with morphine (PCA) on the early postoperative respiratory function after lobectomy. STUDY DESIGN: Prospective and comparative observational study. PATIENTS AND METHODS: Fourty-four patients scheduled for lobectomy (n=22 per group) were studied on the evolution of the postoperative respiratory function assessed by the forced vital capacity (FVC) and the forced expired volume (FEV(1)) during the first two postoperative days and the analysis of noctural arterial desaturation during the three first postoperative nights. RESULTS: The use of TEA resulted in fewer decrease both in FEV(1) (1.01+/-0.34 versus 1.31+/-0.51 l/s for Day 1, P=0.03; 1.13+/-0.37 versus 1.53+/-0.59 l/s for Day 2, P=0.01) and in FVC (1.23 [1.05-1.51] versus 1.57 [1.38-2.53] l for day 1, P=0.008; 1.33+/-0.43 versus 2.24+/-0.87 l for day 2, P<0.001). Moreover, the duration of arterial desaturation<90% were longer in the PCA group during the first (8.6 [0.8-28.2] versus 1.3 [0-2.6] min, P=0.02) and the second postoperative night (13.5 [3.5-54] versus 0.4 [0-2.6] min, P=0.025). CONCLUSION: The results of this study suggest that the use of TEA is associated with a better preservation of respiratory function assessed by spirometric data and noctural arterial desaturation recording after thoracic surgery for lobectomy.