Effectiveness of antimicrobial photodynamic therapy (AmPDT) on <Emphasis Type="Italic">Staphylococcus aureus</Emphasis> using phenothiazine compound with red laser

The aim of this study was to evaluate, in vitro, the bactericidal effect of antimicrobial photodynamic therapy (AmPDT) using phenothiazinium dyes (Toluidine Blue O and methylene blue, 1:1) using different concentrations (100, 50, 25, 12.5, and 6.25 μg/mL) associated to red laser with different energy densities (2.4, 4.8, 7.2, 9.6, and 12 J/cm²) on a strain of Staphylococcus aureus (ATCC 23529). On this study, tests were performed in triplicate and the samples were distributed into 36 test groups: Control and bacterial suspensions were irradiated with the different energy densities, respectively, in the absence of photosensitizer, bacterial suspensions were irradiated with the laser in the different concentrations of the photosensitizer, and finally bacterial suspensions only in the presence of phenothiazinium dye. The pre-irradiation time was 5 min. Therefore, we analyzed the potential of the AmPDT by counting colony-forming units. The logarithm of CFU/mL (log10 CFU/mL) was calculated and the data was analyzed statistically (ANOVA, Tukey’s test, p?<?0.05). The results showed that the association 50 and 100 μg/mL with 12 J/cm² showed the highest percentage of inhibition (100 %). Based upon the present results, it may be concluded that the AmPDT was able to enhance the antimicrobial effect of phenothiazines and both concentration of the compound and energy density are important factors for greater effectiveness of therapy.     

Antimicrobial,modulatory and chemical analysis of the oil of Croton limae

Context: Croton sp. are plants with a well-reported antimicrobial activity. Croton limae A.P. Gomes, M.F. Sales P.E. Berry (Euphorbiaceae), known as ‘marmeleiro-prateado’, is commonly used to manage abdominal pain in Brazil.

Objective: This work evaluates the phytochemical composition, antimicrobial and modulatory activities of the essential oil of C. limae leaves (EOCL).

Materials and methods: The minimum inhibitory concentration (MIC) and the modulation of the antibiotic activity were determined using a microdilution method. The concentration of EOCL ranged between 512 and 8?μg/mL. Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumonia, Candida tropicalis, C. krusei and C. albicans strains were used in the MIC and modulation assays. The antibiotics, amikacin, gentamicin and neomycin, and the antifungals, amphotericin B, benzoylmetronidazole and nystatin, were used in concentrations ranging between 2500 and 2.5?μg/mL. The phytochemical analysis of the EOCL was performed through gas chromatography coupled to a mass spectrometer (GC/MS).

Results: Only Staphylococcus aureus was inhibited by a clinically relevant concentration of EOCL (MIC 512?μg/mL). Synergism between the EOCL and amikacin against S. aureus (9.76?μg/mL) and E. coli (39.062?μg/mL); neomycin against E. coli (2.44?μg/mL); and benzoylmetronidazole against C. krusei (256?μg/mL) were observed. The GC/MS analysis identified cedrol, eucalyptol and α-pinene as the main compounds of EOCL.

Conclusion: EOCL inhibited the growth of S. aureus and potentiated the antibiotic and antifungal effects of drugs against all bacterial and Candida strains, respectively.     

Dissection of the Effects of Quercetin on Mouse Myocardium

Quercetin is a plant flavonoid with several biological activities. This study aimed to describe quercetin effects on contractile and electrophysiological properties of the cardiac muscle as well as on calcium handling. Quercetin elicited positive inotropism that was significantly reduced by propranolol indicating an involvement of the sympathetic nervous system. In cardiomyocytes, 30 μM quercetin increased I_Ca,L at 0 mV from ?0.95 ± 0.01 A/F to ?1.21 ± 0.08 A/F. The membrane potential at which 50% of the channels are activated (V_0.5) shifted towards more negative potentials from ?13.06 ± 1.52 mV to ?19.26 ± 1.72 mV and did not alter the slope factor. Furthermore, quercetin increased [Ca²⁺]_i transient by 28% when compared to control. Quercetin accelerated [Ca²⁺]_i transient decay time, which could be attributed to SERCA activation. In resting cardiomyocytes, quercetin did not change amplitude or frequency of Ca²⁺ sparks. In isolated heart, quercetin increased heart rate and decreased PRi, QTc and duration of the QRS complex. Thus, we showed that quercetin activates β‐adrenoceptors, leading to increased L‐type Ca²⁺ current and cell‐wide intracellular Ca²⁺ transient without visible changes in Ca²⁺ sparks.     

In Vitro Effects of the Neolignan 2,3‐Dihydrobenzofuran Against Leishmania Amazonensis

Leishmaniasis is an infectious disease complex caused by protozoa from the Leishmania genus, which presents a broad spectrum of clinical manifestations: cutaneous, mucocutaneous and visceral forms. The current treatments are unsatisfactory considering that few drugs are available and present some level of toxicity. Many lignans and neolignans have been used for the development of new antileishmania drugs. The capability in vitro of the neolignan 2,3‐dihydrobenzofuran (2,3‐DBF), a commonly found constituent of propolis and other plants, to inhibit the growth of promastigote and macrophage‐internalized amastigote forms of Leishmania amazonensis was investigated. The cytotoxicity of this compound was assessed by MTT (3‐[4,5‐dimethylthiazol‐2‐yl]‐2,5‐diphenyltetrazolium bromide) test in BALB/c murine macrophages and human erythrocyte lysis assay. The 2,3‐DBF was active against promastigote (IC₅₀=1.042 μM) and amastigote (IC₅₀=1.43 μM) forms, indicating a potent antileishmanial effect. There was no evidence of cytotoxicity to macrophages or erythrocytes at concentrations ranging from 13 to 0.5 μM, after 48 hr of exposure. The antileishmanial activity is probably mediated by the activation of macrophages, because treatment with 2,3‐DBF increases both phagocytic and lysosomal activities, as well as the nitrite (NO₂^?) levels. These results suggest that 2,3‐DBF may be a potential candidate for the development of a new promising antileishmanial drug. Further studies are needed to determine its potential in vivo effect as well as additional mechanisms underlying the antileishmanial and immunomodulatory activities.     

Detection of air gaps around the cylinder by postinsertion computed tomography in vaginal cuff brachytherapy: A prospective series,systematic review,and meta-analysis

PurposePostinsertion computed tomography (CT) can identify air gaps (AGs) around the cylinder in vaginal cuff brachytherapy (VCB). This study investigates the incidence and location of AGs.Methods and MaterialsPlanning CTs of 22 prospectively recruited patients (NCT02091050) treated with 2.6 cm (n = 8) and 3.0 cm (n = 14) cylinders were evaluated. In addition, a systematic literature review and meta-analysis was performed (PubMed and EMBASE). The pooled incidence of AGs was calculated by using the random-effects model weighted by inverse variance.ResultsIn 18 cases (82%), a total of 45 AGs were found: 26 within the 2 cm cranial length and 19 between 2 and 4 cm of the cylinder. The mean AG diameter was 3.7 mm (range: 1.3–11.8). Cylinder diameter, primary tumor site, and use of external beam radiotherapy were not associated with AG incidence. Systematic literature review revealed nine additional relevant studies, totaling 657 patients. The pooled incidence of patients with ≥1 AG was 67% (95% confidence interval: 50–83). AGs were located at the apex in 43.4%–94.4% of cases. In patients with ≥1 AG (n = 244), the pooled mean number of AGs was 2.18 per patient. The mean dose reduction varied from 9.6% to 29.3%.ConclusionMore than two-thirds of VCB cases present with AGs, which are most commonly at the apex and can potentially reduce mucosal dose. By identifying AGs, postinsertion CT can facilitate selection of optimal cylinder size in VCB.     

Effective resolution of the Y chromosome sublineages of the Iberian haplogroup R1b-DF27 with forensic purposes

Single-nucleotide polymorphisms (SNPs) found within the non-recombining region of the Y chromosome (NRY) represent a powerful tool in forensic genetics for inferring the paternal ancestry of a vestige and complement the determination of biogeographical origin in combination with other markers like AIMs. In the present study, we introduce a panel of 15 Y-SNPs for a fine-resolution subtyping of the haplogroup R1b-DF27, in a single minisequencing reaction. This is the first minisequencing panel that allows a fine subtyping of R1b-DF27, which displays high frequencies in Iberian and Iberian-influenced populations. This panel includes subhaplogroups of DF27 that display moderate geographical differentiation, of interest to link a sample with a specific location of the Iberian Peninsula or with Iberian ancestry. Conversely, part of the intricacy of a new minisequencing panel is to have all the included variants available to test the effectiveness of the analysis method. We have overcome the absence of the least common variants through site-directed mutagenesis. Overall, the results show that our panel is a robust and effective method for subtyping R1b-DF27 lineages from a minimal amount of DNA, and its high resolution enables to improve male lineage discrimination in Iberian and Southwest European descent individuals. The small length of the amplicons and its reproducibility makes this assay suitable for forensic and population genetics purposes.

     

The fate of isoprenaline in the isolated rabbit aorta

Summary The fate of isoprenaline (ISO) was studied in the intact rabbit aorta, as well as in the isolated adventitia and isolated media, by means of liquid scintillation counting of ³H-ISO and ³H-O-methylisoprenaline (OMI) as well as by autoradiography of tissues incubated with 2M ISO. The 3 preparations accumulated and O-methylated ISO; O-methylation was proportionally higher in the intact vessel than in its constituents. The isolated adventitia differed from the other preparations in reaching a steady-state of cortexone-resistant accumulation after 8 min of incubation and in exhibiting an O-methylating capacity which was partly resistant to the COMT inhibitor, U-0521. The effect of cocaine gave evidence for a participation of neuronal uptake in the accumulation of the amine in the intact aorta. In the media, most of the accumulation occurred in smooth muscle cells and was reduced by cortexone and increased by U-0521; elastin and collagen, present both in the media and the adventitia, showed accumulation which was not affected by the inhibitory drugs studied.The results show that in the rabbit aorta there is a corticosteroid-resistant uptake mechanism (which predominates in the adventitia) which involves structures devoid of COMT activity. Furthermore, smooth muscle cells represent, in the media, the extraneuronal metabolizing site of loss. The adventitia is a complex layer, with different types of cells which may intervene in accumulation and metabolism of ISO. Therefore, it is concluded that the isolated media represents an acceptable model for the study of both corticosteroidsensitive and-resistant extraneuronal mechanisms, whereas the isolated adventitia is characterized by the presence of neuronal and extraneuronal mechanisms.Some of the results were presented to the 3rd Meeting on Adrenergic Mechanisms, Porto, July 12–13, 1978 (Proceedings, p. 93) and to the 1st Joint Meeting of the Spanish and Portuguese Pharmacological Societies (Santiago de Compostela, 21–23.5.79). Supported by Instituto Nacional de Investigação Científica (Centro de Farmacologia e Biopatologia Quimica-FmPl)