Action mechanisms of probiotics on Candida spp. and candidiasis prevention: an update.

Due to the high incidence of fungal infections caused by Candida species and their increasing resistance to antimicrobial treatments, alternative therapies such as probiotics have been studied. It has been show that several species of the genus Lactobacillus have anti-Candida activity, probably by direct inhibition, through competition for adhesion sites or production of secondary metabolites, and by indirect inhibition, through stimulation of the immune system of their host. However, the mechanisms of inhibition of these probiotics on Candida species have not yet been fully elucidated since this effect is related to more than one inhibition pathway. In the literature, several in vitro and in vivo studies have been developed seeking to elucidate the probiotics mechanisms of action. These studies have been focused on C. albicans inhibition assays, including analysis of antimicrobial activity, adherence capacity, biofilms formation, filamentation and interference on virulence genes, as well as assays of experimental candidiasis in invertebrate and vertebrate models. In this context, the purpose of this review was to gather different studies focused on the action mechanism of probiotic strains on Candida sp. and to discuss their impact on the candidiasis prevention.

Effects of Manufacturing and Finishing Techniques of Feldspathic Ceramics on Surface Topography, Biofilm Formation, and Cell Viability for Human Gingival Fibroblasts.

PURPOSE:: Feldspathic ceramic restorations can be obtained by different techniques (stratification or computer-aided design/computer-aided manufacturing [CAD/CAM] blocks) and finishing procedures (polishing or glaze application). This study evaluated the effects of techniques and finishing procedures on surface properties, biofilm formation, and viability of human gingival fibroblasts (FMM-1) in contact with these materials. METHODS AND MATERIALS:: Ceramic specimens were obtained through a stratification technique (Vita VM9) and from CAD/CAM blocks (Vita Blocs Mark II; both Vita Zahnfabrik) and their surfaces were finished by polishing (ceramisté diamond rubbers + polishing paste; "p" subgroups) or glaze spray application + sintering ("g" subgroups). Roughness (Ra and RSm parameters) and surface free energy (SFE) were measured. Early biofilm formation of Streptococcus mutans, Streptococcus sanguinis, and Candida albicans was evaluated by counting colony-forming units (CFU). MTT (3-[4.5-dimethyl-thiazol-2-yl-]-2.5-diphenyl tetrazolium bromide) cytotoxicity test evaluated cellular viability for the growth of FMM-1 after 24 hours and seven days of contact. Scanning electron microscopy (SEM) and three-dimensional optical profilometry were performed to qualitatively analyze the surface. Data were analyzed by analysis of variance, Tukey test, and t-test (all α=0.05). RESULTS:: Polished samples presented lower roughness (Ra, p=0.015; RSm, p=0.049) and higher SFE ( p=0.00). Streptococci had higher CFU in all groups, but the CFU of C albicans was lower for polished samples. Biofilm formation was influenced by the interaction of all factors ( p=0.018), and the materials showed no cytotoxicity to FMM-1 growth. CONCLUSIONS:: Polishing resulted in the lowest values for surface roughness and higher SFE values. Polished ceramics showed less C albicans adherence while the adherence of Streptococci was greater than C albicans in all conditions.

Monolithic Ceramics: Effect of Finishing Techniques on Surface Properties, Bacterial Adhesion and Cell Viability.

INTRODUCTION: This study evaluated the morphology, biofilm formation, and viability of human gingival fibroblasts in contact with two monolithic ceramics after two different finishing techniques: polishing or glazing. For this, 92 blocks (4.5 × 4.5 × 1.5 mm) of each ceramic were made using high translucency zirconia partially stabilized by yttrium (YZHT) and lithium silicate reinforced by zirconium (ZLS). METHODS AND MATERIALS: Blocks were sintered and then divided into glazing (g) or polishing (p) surface finish. Surface roughness (Ra and RSm) was evaluated through a contact rugosimeter and profilometry. Specimens were contaminated for heterotypic biofilm formation with Streptococcus mutans, Streptococcus sanguinis and Candida albicans for 16 hours. Biofilm was quantified by counting the colony forming units (CFU/mL) and analyzed by scanning electron microscopy (SEM). Fibroblast viability was evaluated by MTT assay. Surface free energy (SFE) was also determined. Roughness data were evaluated using nonparametric tests, while SFE, MTT and CFU results were evaluated by analysis of variance and Tukey test, and MTT data were also submitted to t-test (all, α=0.05). RESULTS: Results showed that polished samples presented a lower high profile mean ( p<0.001); however, YZHTg presented less space between defects ( p=0.0002). SFE showed that YZHT presented higher SFE than ZLS. Profilometry evidenced more homogeneity on polished surfaces. The interaction of finishing technique and microorganisms influenced the CFU ( p=0.00). MTT assay demonstrated initial severe cytotoxic behavior for polished surfaces. SEM images showed homogeneous surfaces, except for glazed YZHT. CONCLUSION: Glazed surfaces have a greater roughness and tend to accumulate more biofilm. Polished surfaces have higher SFE; however, they are temporarily cytotoxic.

Natural radioactivity in soils of the state of Rio de Janeiro (Brazil): Radiological characterization and relationships to geological formation, soil types and soil properties.

Located in the south-western part of Brazil, the state of Rio de Janeiro is geotectonically contained within a complex structural province that resulted in the amalgamation of the Western Gondwana Paleocontinent. To undertake an extensive radiological characterization of this complex geological province and investigate the influence of bedrock, soil type and soil chemical-physical characteristics on natural radionuclide levels in soils, 259 surface soil samples were collected that encompassed the main soil types and geological formations throughout the state. Gamma spectrometry analysis of the samples resulted in median values of 114 Bq.kg-1for 40K, 32 Bq.kg-1 for 226Ra and 74 Bq.kg-1 for 228Ra. The median value for 226Ra was similar to the world median value for soils, the 40K value was well below the worldwide value, and that for 228Ra exceeded the world median value. The intense weathering caused by the high rainfall rates and high temperatures may be responsible for the low levels of 40K in the soils, of which the strongly acidic and clayey soils are markedly K-depleted. A soil from a high-grade metamorphic rock (granulite) presented the lowest 226Ra (18 Bq.kg-1) content, whereas the highest levels for 226Ra (92 Bq.kg-1) and 228Ra (139 Bq.kg-1) were observed in a young soil enriched in primary minerals (Leptsol). A lowland soil (Gleysol) showed the highest median of 40K (301 Bq.kg-1). Strongly acidic soils tended to present high amounts of 226Ra, and sandy soils tended to contain low levels of 228Ra. The external radiation dose indicates that the state has a background radiation level within the natural range.

Lactobacillus rhamnosus inhibits Candida albicans virulence factors in vitro and modulates immune system in Galleria mellonella.

AIM: The aim of this study was to evaluate the potential anti-Candida effects of Lactobacillus rhamnosus ATCC 9595 on Candida albicans ATCC 18804 using in vitro and in vivo models. METHODS AND RESULTS: The in vitro analysis evaluated the effects of L. rhamnosus on C. albicans's biofilm formation by CFU count and metabolic activity, filamentation capacity, and adhesion (ALS3 and HWP1) and transcriptional regulatory gene (BCR1 and CPH1) expression. The in vitro results showed that both the L. rhamnosus cells and supernatant reduced C. albicans biofilm formation, filamentation and gene expression. In the in vivo study, the treatment with L. rhamnosus supernatant increased 80% the survival of Galleria mellonella larvae infected with C. albicans. Furthermore, the supernatant of L. rhamnosus recruited haemocytes into the haemolymph (2·1-fold increase). CONCLUSIONS: Lactobacillus rhamnosus reduced the biofilm formation and filamentation of C. albicans in vitro by negatively regulating all studied C. albicans genes. Lactobacillus rhamnosus protected G. mellonella against experimental candidiasis in vivo. SIGNIFICANCE AND IMPACT OF THE STUDY: This study is the first study to report the anti-Candida properties of L. rhamnosus ATCC 9595. The supernatant of this strain has immunomodulatory effects on the G. mellonella model and protects the larvae against pathogens.

Cardiovascular and behavioral effects produced by administration of liposome-entrapped GABA into the rat central nervous system.

Liposomes are nanosystems that allow a sustained release of entrapped substances. Gamma-aminobutyric acid (GABA) is the most prevalent inhibitory neurotransmitter of the central nervous system (CNS). We developed a liposomal formulation of GABA for application in long-term CNS functional studies. Two days after liposome-entrapped GABA was injected intracerebroventricularly (ICV), Wistar rats were submitted to the following evaluations: (1) changes in mean arterial pressure (MAP), heart rate (HR) and renal sympathetic nerve activity (RSNA) to ICV injection of bicuculline methiodide (BMI) in anesthetized rats; (2) changes in cardiovascular reactivity to air jet stress in conscious rats; and (3) anxiety-like behavior in conscious rats. GABA and saline-containing pegylated liposomes were prepared with a mean diameter of 200 nm. Rats with implanted cannulas targeted to lateral cerebral ventricle (n = 5-8/group) received either GABA solution (GS), empty liposomes (EL) or GABA-containing liposomes (GL). Following (48 h) central microinjection (2 µL, 0.09 M and 99 g/L) of liposomes, animals were submitted to the different protocols. Animals that received GL demonstrated attenuated response of RSNA to BMI microinjection (GS 48 ± 9, EL 43 ± 9, GL 11 ± 8%; P < 0.05), blunted tachycardia in the stress trial (ΔHR: GS 115 ± 14, EL 117 ± 10, GL 74 ± 9 bpm; P<0.05) and spent more time in the open arms of elevated plus maze (EL 6 ± 2 vs. GL 18 ± 5%; P = 0.028) compared with GS and EL groups. These results indicate that liposome-entrapped GABA can be a potential tool for exploring the chronic effects of GABA in specific regions and pathways of the central nervous system.

Lead poisoning risk for dairy cows in the semi-arid region of Pernambuco, Brazil.

The lead (Pb) isotopes ²°6Pb and ²°8Pb are the final products of the radioactive decay of ²³8U and ²³²Th, respectively. Soils in the municipalities of Pedra and Venturosa, Brazil, present high levels of these radionuclides. We hypothesized that forage plants growing in these soils may take up high amounts of Pb and, consequently, intoxicate dairy cows. To test this, we quantified Pb concentrations in 23 forage samples from this region. Pb concentrations varied from 5 to 344 mg kg⁻¹. The highest values are one order of magnitude above the reported limit, therefore, indicating high risk of Pb contamination for dairy cows.

Estimation of dose due to ingestion of (210)pb in milk from dairy cattle in the semi-arid region of Pernambuco, Brazil.

(210)Pb is widely distributed in the environment. In this context, the aim of this research has been: (1) to determine (210)Pb concentrations in milk and dairy products from farms located in the cities of Pedra and Venturosa in Pernambuco, Brazil; and (2) to calculate the dose due to the ingestion of (210)Pb in these products. The ion exchange resin method was used and the concentration of (210)Pb varied from 62 to 650 mBq l(-1) in fresh milk, from 202 to 1,494 mBq kg(-1) in curdled cheese and from 11 to 253 mBq l(-1) in milk whey. The estimated dose due to ingestion of milk and dairy products in this region was 0.2 Sv, which is at least two orders of magnitude above the maximum recommended levels.

Comparison of two concentrations of NALC-NaOH for decontamination of sputum for mycobacterial culture.

This study compared the effect of using two different concentrations of sodium hydroxide (NaOH) in the N-acetyl-L-cysteine-sodium hydroxide (NALC-NaOH) method for sputum decontamination on smear and culture positivity and the proportion of contaminated cultures: 14% of cultures were contaminated using the standard final 1% NaOH concentration during processing compared to 11% contaminated cultures using a final 1.25% NaOH concentration (P < 0.008). The proportion of cultures positive for mycobacteria decreased from 21% to 11% for sputum processed with 1% and 1.25% final NaOH concentrations, respectively (P < 0.001). Our findings suggest that a small reduction in culture contamination did not justify the considerable loss of positive cultures.

210Pb in forage consumed by dairy cows.

The aim of this research was to determine (210)Pb concentrations in forage from farms located in the municipalities of Pedra and Venturosa, in the Brazilian state of Pernambuco, where rolled blocks of mafic rock with a high percentage of U(3)O(8) were found. The concentrations of (210)Pb varied from 2 to 503 Bq kg(-1) in the forage dry matter samples evaluated. Due to the elevated levels of (210)Pb in the forage samples, it is concluded that this radionuclide is highly available to be ingested by dairy cows and this could represent a hazard to the human population due to possible milk contamination.

Radium and uranium levels in vegetables grown using different farming management systems.

Vegetables grown with phosphate fertilizer (conventional management), with bovine manure fertilization (organic management) and in a mineral nutrient solution (hydroponic) were analyzed and the concentrations of (238)U, (226)Ra and (228)Ra in lettuce, carrots, and beans were compared. Lettuce from hydroponic farming system showed the lowest concentration of radionuclides 0.51 for (226)Ra, 0.55 for (228)Ra and 0.24 for (238)U (Bq kg(-1) dry). Vegetables from organically and conventionally grown farming systems showed no differences in the concentration of radium and uranium. Relationships between uranium content in plants and exchangeable Ca and Mg in soil were found, whereas Ra in vegetables was inversely correlated to the cation exchange capacity of soil, leading to the assumption that by supplying carbonate and cations to soil, liming may cause an increase of U and a decrease of radium uptake by plants. The soil to plant transfer varied from 10(-4) to 10(-2) for (238)U and from 10(-2) to 10(-1) for (228)Ra.

Diagnóstico da pneumonia enzoótica suína pela técnica da imunoperoxidase / Immunoperoxidase technique for diagnosis of enzootic pnemonia in swine

Avaliou-se a técnica da imunoperoxidase como método auxiliar para a detecção de Mycoplasma hyopneumoniae em suínos naturalmente infectados. Foram colhidos 80 fragmentos de pulmões de 40 animais provenientes de granjas consideradas negativas e 40 de granjas com diagnóstico positivo de pneumonia enzoótica. Com a utilização de soro policlonal específico (IgG de coelho anti- M. hyopneumoniae) observou-se correlação positiva de 77 por cento entre os diagnósticos microscópicos e imunoistoquímicos, enquanto que a correlação entre os diagnósticos macroscópico e imunoistoquímico foi de 49 por cento. Nas granjas consideradas negativas observou-se presença de discreta imunorreação em 22,5 por cento dos casos, o que poderia indicar a existência de reação cruzada com outros microrganismos. Nas granjas com diagnóstico positivo para pneumonia enzoótica a técnica da peroxidase-anti-peroxidase (PAP) revelou diferentes graus de intensidade, variando de fraca imunomarcação até espesso depósito amarronzado no epitélio ou na luz das vias aéreas, ou ainda no interior de macrófagos, com relação direta entre a intensidade das lesões e da imunorreação. A técnica imunoistoquímica possui sensibilidade de 95 por cento e especificidade de 77,5 por cento, podendo ser recomendada como ferramenta auxiliar, rápida e de baixo custo para o diagnóstico de pneumonia enzoótica suína em laboratórios de rotina em histopatologia.

A whole blood bactericidal assay for tuberculosis.

The bactericidal activity of orally administered antituberculosis (anti-TB) drugs was determined in a whole blood culture model of intracellular infection in which microbial killing reflects the combined effects of drug and immune mechanisms. Rifampin (Rif) was the most active compound studied and reduced the number of viable bacilli by >4 logs. Isoniazid (INH), 2 quinolones, and pyrazinamide (PZA) showed intermediate levels of activity. Ethambutol exerted only a bacteristatic effect; amoxicillin/clavulanate was inactive. The combination of INH-Rif-PZA showed strong activity against 11 drug-sensitive isolates (mean, -3.8 log) but no activity against 12 multidrug-resistant (MDR) strains. The combination of levofloxacin-PZA-ethambutol had intermediate bactericidal activity against MDR isolates (mean, -1.2 log) but failed to equal that of INH-Rif-PZA against sensitive isolates (P<.001). The whole blood BACTEC method (Becton Dickinson) may be useful for the early clinical evaluation of new anti-TB drugs and in the management of individual patients.

Comparison of time course of neuromuscular blockade in young children following rocuronium and atracurium.

In order to compare the neuromuscular effects following rocuronium 0.6 mg kg-1 and atracurium 0.5 mg kg-1 30 children aged from 18 to 67 months were studied under the same anaesthetic conditions. After induction of anaesthesia with etomidate and fentanyl, neuromuscular blockade was monitored by recording the electromyographic response of the adductor pollicis muscle to a supramaximal train-of-four (TOF) stimulation of the ulnar nerve at 2 Hz for 2 s at 20-s intervals. Intubation was performed when more than 90% muscle relaxation was achieved, thereafter anaesthesia was maintained with 70% nitrous oxide in oxygen and isoflurane 0.5% end-tidal. Mean onset of action was significantly faster following rocuronium (86 +/- 44.9 s) (mean +/- SD) compared with atracurium (126.3 +/- 61.0 s). Clinical duration with rocuronium was 22.8 +/- 5.31 min and thus significantly shorter than that of atracurium, which was 31.5 +/- 6.01 min. A statistically significant difference between rocuronium and atracurium also had been found for recovery of T1 to 50%, 75% and 90% as well as for the time taken to a TOF ratio of 70%. The recovery index for rocuronium and atracurium was not significantly different with 9.2 +/- 3.43 min and 10.9 +/- 2.65 min, respectively. Thus, rocuronium may be more advantageous than atracurium for short-lasting surgical procedures in young children.

Intubating conditions and onset of action after rocuronium, vecuronium, and atracurium in young children.

To evaluate muscle relaxant onset times and tracheal intubating conditions, 60 children (ASA physical status I or II) aged 18 to 72 mo were randomly assigned to receive a bolus of either rocuronium 0.6 mg/kg, vecuronium 0.1 mg/kg, or atracurium 0.5 mg/kg. After induction of anesthesia with etomidate 0.2-0.4 mg/kg and fentanyl 1-3 mg/kg, lungs were ventilated with 50% nitrous oxide in oxygen via a face mask. The evoked electromyogram of the adductor pollicis to a train-of-four stimulation every 20 s was monitored. After administration of the muscle relaxant, endotracheal intubation was attempted every 30 s, beginning 30 s after drug administration, until intubation could be achieved with good or excellent conditions. Rocuronium produced acceptable intubating conditions significantly faster (all tracheas intubated within 60 s) compared with vecuronium (120 s) and atracurium (180 s). The quality of intubating conditions at the time of completed intubation was rated significantly better with rocuronium than with vecuronium or atracurium. However, onset to 95% block at the adductor pollicis muscle was not significantly different after rocuronium (92 +/- 46.9 s), vecuronium (112 +/- 33.3 s), or atracurium (134 +/- 57.1 s), and mean neuromuscular block achieved at the point of successful intubation was not complete in all groups. We conclude that clinically acceptable intubating conditions are produced more rapidly with rocuronium than with atracurium or vecuronium.

Deep sedation with propofol in preschool children undergoing radiation therapy.

Immobilization of children undergoing radiation therapy always requires anaesthesia. Deep sedation with continuous infusion of propofol and spontaneous breathing, (we call it ¿sedative anaesthesia'), may be an alternative to general anaesthesia with intubation and controlled ventilation. This clinical report deals with 155 anaesthetics performed in 11 consecutive paediatric oncology patients, mean age 30 months (range 19-42), who required radiation therapy for from seven to 33 consecutive days. Mean duration of anaesthesia was 18 ( +/- 11) mins. For induction, a loading dose of 3.6 (SD +/- 0.59) mg.kg-1 propofol was administered immediately followed by a continuous infusion of 7.4 ( +/- 2.2) mg.kg-1.h-1 for maintenance of anaesthesia. There were no complications of clinical importance involving respiration, circulation or neurology, except for one short episode of transient desaturation, which was managed by suctioning and changing head position. Children opened their eyes spontaneously four ( +/- 3.7) min after discontinuing the propofol infusion and could be discharged about 30 mins later. Tachyphylaxis or unpleasant side effects during and after anesthesia have not been observed. Sedative anaesthesia with propofol seems to be an excellent method to immobilize paediatric patients during radiotherapeutic procedures.

[Plethysmechanomyography (PMG). A simple method for monitoring muscle relaxation]. / Die Plethysmo-Mechanomyographie (PMG). Eine einfache Methode zur Erfassung der Muskelrelaxation.

Ideal evaluation of neuromuscular blockade can be done by mechanical or electromyographical registration of muscle contractions evoked by ulnar nerve stimulation. Unfortunately, devices needed for such registration are expensive or complicated to set up, and thus are not often used for routine monitoring in anaesthesia. In this study, we describe a simple and low-priced method permitting intra- and postoperative monitoring of neuromuscular blocking agents. The accuracy of plethysmomechanomyography (PMG) was evaluated by comparing simultaneous electromyographic (EMG) and plethysmographic measurements. METHODS. For plethysmographic registration of muscle response to nerve stimulation a simple infusion system is twisted there to five times around one hand and connected to an anaesthetic monitor via a pressure transducer. The drip chamber is fixed about 20 cm above the hand (Fig. 1). Then, the infusion system is then filled up-with physiologic saline solution and the clamp is nearly closed. Electric stimulation can be carried out using any nerve stimulator. Using this method, PMG mainly records the contractions of abductor digiti minimi muscle, but also partly those of the interossei. Evoked muscle contractions cause stretching of the infusion system, which leads to pressure changes proportional to the strength of contraction. The muscle response to "train-of-four" (TOF) stimulation of the ulnar nerve was recorded simultaneously by EMG and PMG in 11 patients (ASA class I or II) undergoing neurosurgical procedures and therefore requiring muscle relaxation. After induction of anaesthesia by injection of etomidate and fentanyl, supramaximal stimulation and control values (T0) were defined. Anaesthesia was maintained by supplementation with nitrous oxide/oxygen (1:2) and muscle relaxation was carried out with vecuronium. We used the integrated nerve stimulator of a Datex Relaxograph NMT-100 EMG monitor and proceeded to stimulate the ulnar nerve at the forearm with supramaximal strength. The PMG was registered by a Siemens Siredoc 220 printer connected to a Siemens Sirecust 1281 anaesthetic monitor. First twitch ratio (T1/T0) and TOF ratio (T4/T1) were calculated from these recordings. The EMG recordings were made by a Datex Relaxograph NMT-100 monitor, which automatically computes T1/T0 and T4/T1. The comparison of EMG and PMG values was carried out by simple linear regression. Statistical evaluation was performed using analysis of variance. RESULTS. A plethysmographically registered graph of the TOF-evoked muscle response is illustrated in Fig. 2. Simultaneous EMG and PMG recordings of onset and recovery from a nondepolarizing blockade are shown in Fig. 3. A strong positive correlation (P < 0.001) of EMG and PMG was found with correlation coefficients of 0.98 for T1/T0 and of 0.97 for T4/T1. The mean difference between values of both methods was 5%, maximally 18% (T1/T0) and 20% (T4/T1). CONCLUSIONS. Mechanomyography and EMG are well established methods of neuromuscular monitoring. Our data demonstrate that PMG provides a reliable measurement of neuromuscular transmission that correlates well with EMG. Since only materials of daily use in anaesthesia are needed, no substantial costs will arise when the plethysmographic method of measurement is used for routine anesthetic monitoring.