Silver Nanoparticles Biosynthesized with Spruce Bark Extract-A Molecular Aggregate with Antifungal Activity against Candida Species.

Due to their high content of biomolecules, combined with silver's well known antimicrobial potential, silver nanoparticles biosynthesized using spruce bark (AgNP SBEs) demonstrate antibacterial and antioxidant activity, making them a versatile option for developing new antimicrobial agents that might be used for medical treatment or as adjuvants for the classical agents. This study aims to analyze if silver nanoparticles (AgNPs) mediated by spruce bark extract (SBE) and silver salts (AgNP SBE Acetate, AgNP SBE Nitrate) presents antifungal activity against five different Candida spp., synergistic activity with fluconazole, and if they interact with some virulence factors of C. albicans. AgNP SBEs presented MICs (minimum inhibitory concentrations) for all the five tested Candida spp. AgNP SBEs inhibited the growth of C. parapsilosis, C. krusei, and C. guilliermondii, exerted synergistic activity with fluconazole for C. parapsilosis and C. guilliermondii, and inhibited biofilm production for C. albicans, C. auris, and C. guilliermondii. MICs of AgNP SBE Acetate significantly inhibited the production of germ tubes of C. albicans. The expression of C. albicans SAP2 gene was down-regulated by the short-time treatment with MICs of AgNP SBE Acetate, while ALS3 and HSP70 genes were up-regulated by the AgNPs MICs. These results emphasize the potential of using the AgNP SBEs as treatments/adjuvants options, not only against the redundant C. albicans but also for the non-albicans Candida species (which are not as frequently involved in human pathologies, but, sometimes, can be more aggressive).

In Vitro Antifungal Activity of Silver Nanoparticles Biosynthesized with Beech Bark Extract.

Biosynthesis is a green method for the synthesis of silver nanoparticles (AgNPs). This study aimed to assess the antifungal activity of two silver nanoparticle solutions, synthesized using beech bark extract (BBE) and acetate and nitrate silver salts (AgNP Acetate BBE and AgNP Nitrate BBE), their influence on biofilm production, their potential synergistic effects with fluconazole, on different Candida spp., and their influence on virulence factors of C. albicans (germ tube production, gene expression for ALS3, SAP2, HSP70). Both the AgNP BBEs presented different minimum inhibitory concentrations for all the studied Candida spp., but biofilm production was inhibited only for C. albicans and C. guilliermondii. The growth rates of all the studied Candida spp. were inhibited in the presence of both AgNP BBEs, except for C. auris. Synergistic activity was observed for C. parapsilosis and C. guilliermondii, for different combinations of fluconazole with both the AgNP BBEs. The germ tube production of C. albicans was slightly inhibited by the AgNP BBEs. Only AgNP Acetate BBE was able to down-regulate the expression of SAP2. Overall, we can conclude that, even if more studies are necessary, AgNPs synthesized with beech bark extract might be an interesting alternative to classic antifungal treatments.

[Etiopathological factors of hepatocellular carcinoma in Bangui, Central African Republic: clinical, biological characteristics and virological aspects of patients]. / Etiopathologie du carcinome hépatocellulaire à Bangui, République centrafricaine : caractéristiques cliniques, biologiques et aspects virologiques des patients.

OBJECTIVES: To describe clinical, biological characteristics and virological aspects of patients with hepatocellular carcinoma (HCC). PATIENTS AND METHODS: Sera obtained from consent patients with clinical suspicion of HCC. Routine biochemical tests and serological markers of hepatitis B virus (HBV), hepatitis D virus (HDV) and hepatitis C virus (HCV) were searched. A hepatic ultrasound scan was realized and, when a suspected mass lesion was observed, ultrasonographic-guided fine needle aspiration of the hepatic mass lesion was made to ascertain the diagnosis of HCC. RESULTS: One hundred and seventy-five sera were collected from 99 men and 76 women. Approximately 96.6% (169/175) of them had previous contact with HBV. HBs surface antigen was positive in 41% (69/169) of whom 53.6% (37/69) were co-infected by the HDV. Three patients (1.71%=3/175) were positive for anti-HCV antibodies. The other three patients (1.71%=3/175) did not present any markers for HBV or HCV. At the time of diagnosis, right upper quadrant pain, hepatomegaly, cachexia, were present in all patients. An increase in serum transaminases (70%), high bilirubin concentrations (40%), high AFP levels (40%) and low prothrombin levels (52%) were the most frequent biological abnormalities. Only 17 guided fine needle aspirations of mass lesions were realized. The diagnosis of HCC was confirmed by cytopathological examination for 14 of them. CONCLUSIONS: HCC is a frequent pathology in the Central African Republic (CAR). According to the ultrasound imaging data, patients consult at terminal stage of the disease. This study confirms also the association between HBV and HCC in CAR. Moreover, in 26.5% of patients HDV is associated with severe forms of the disease.

Characterization of drug-resistance mutations in HIV-1 isolates from non-HAART and HAART treated patients in Burkina Faso.

Non-B HIV subtypes have been estimated to account for 88% of HIV infections in the world. These subtypes are particularly relevant in view of the availability of antiretroviral (ARV) drugs, since subtype-specific mutations are associated with drug-resistance in developing countries. Therefore, the pol gene sequences in HIV-1 isolates were examined from the three distinct groups of 39 infected patients from Ouagadougou in Burkina Faso: 17 patients who had not received any antiretroviral therapy (ART); 16 patients received ART, and 6 HIV-infected children, from infected mothers, received a single Nevirapine dose prophylaxis during birth. HIV-1 pol sequencing was successful for 29 samples. As expected, all patients presented the common (non-B subtype) M36I polymorphism and 26/29 (90%) the K20I mutation. Phylogenetic studies showed high predominance of recombinant HIV-1 strains: CRF06_cpx 16/29 (55.17%), CRF02_AG 9/29 (31.03%), A1 2/29 (6.89%), G 1/29 (3.44%), and CRF09_cpx 1/29 (3.44%). Two twins showed, 6 months after birth, a NNRTI-mutation (Y181C/Y). During the same period, the twin mother presented a different NNRTI-mutation (V106I), thus suggesting that the different blood drug concentration may determine a different drug-resistance pathway. Among 17 non-highly active antiretroviral therapy (HAART) patients, 3/17 (17.64%) presented virus with reverse transcriptase (RT) mutations [V118I: 1/17 patients (5.88%), V179E: 2/17 patients (11.76%)]. 10/17 (58.82%) presented virus with minor protease (PR) mutations [L63P: 5/17 patients (29.41%), V77I: 3/17 patients (17.64%), L10I: 2/17 patients (11.76%)]. 4/17 patients did not show any PR and RT mutations (23.52%). Among six HAART-treated patients, 6/6 and 3/6 had M36I and L63LP protease minor subtypes, respectively; and only two (33.33%) presented virus with K103N mutation. The low prevalence of drug-resistant associated mutations in Burkina Faso is encouraging. However, further studies with a larger cohort with a high non-B subtype prevalence are necessary to optimize ART in developing countries.

Interactions of the dimethyldiazaperopyrenium dication with nucleic acids. 1. Binding to nucleic acid components and to single-stranded polynucleotides and photocleavage of single-stranded oligonucleotides.

The binding of dimethyldiazaperopyrenium dication (1) with nucleosides, nucleotides, and single-stranded polynucleotides has been studied by photophysical methods. It has been shown that 1 may be a potential selective fluorescent probe for A- and/or T-rich polynucleotides. 1 efficiently cleaves oligonucleotides at guanine sites, under illumination with visible light, and therefore may be used as a sequence-specific artificial photonuclease.

[Differences in the properties of antibodies and natural antiglobulin-homoreactants revealed by the method of human IgG chemical modification]. / Ispol'zovanie metoda khimicheskoi modifinkatsii IgG cheloveka dlia dokazatel'stva razlichiia v svoistvakh antitel i estestvennykh antiglobylinovgp, prealtamtpv.

The naturally occurring antiglobulin factors - homoreactants, contained by human IgG preparations, are inactivated as a result of incubation in a solution of sodium rhodanide (3 - 5 M) and sodium desoxycholate (0.005M). Staphylococcal antitoxin contained by the same human IgG preparations is resistant to the action of the reagents. The data obtained indicate the differences in the structure of homoreactants and antibodies.