Publications by authors named "Gustavo P Silveira"

Imidazolium-based dicationic ILs (DILs) presenting antimicrobial activity and relatively low toxicity are highly desirable and are envisioned for use in live tissue to prevent bacterial or fungal infections. In this context, we present here DILs with dicarboxylate anions [C(MIM)[C(MIM)][CO-(CH)CO], in which = 4, 6, 8, and 10, and m = 0, 1, 2, 3, 4, and 5. The results showed that DILs with an alkyl chain spacer of ten carbons were active against yeasts and the bacterial strains tested.

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Development of new antimicrobial agents, capable of combating resistant and multidrug-resistant fungal and bacterial clinical strains, is necessary. This study presents the synthesis and antimicrobial screening of 42 2-substituted-1,4-benzenediols, being 10 novel compounds. In total, 23 compounds showed activity against fungi and/or bacteria.

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Dermatophytes are the etiological agents of cutaneous mycoses, including the prevalent nail infections and athlete's foot. Candida spp. are opportunistic and emerging pathogens, causing superficial to deeper infections related to high mortality rates.

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The purpose of this paper is to describe the glycosylation of ambrisentan (AMB) by cultures of Cunninghamella elegans ATCC 9245. AMB is an endothelin receptor antagonist, which is used to treat pulmonary arterial hypertension. Filamentous fungi are morphologically complex and may exhibit different forms depending on the species and the nature of the culture medium.

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The 8-hydroxyquinoline core is a privileged scaffold for drug design explored to afford novel derivatives endowed with biological activity. Our research aimed at clarifying the antifungal mechanism of action of clioquinol, 8-hydroxy-5-quinolinesulfonic acid, and 8-hydroxy-7-iodo-5-quinolinesulfonic acid (three 8-hydroxyquinoline derivatives). The antifungal mode of action of these derivatives on spp.

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The combination of tools such as time-kill assay with subsequent application of mathematical modeling can clarify the potential of new antimicrobial compounds, since minimal inhibitory concentration (MIC) value does not provide a very detailed characterization of antimicrobial activity. Recently, our group has reported that the 8-hydroxy-5-quinolinesulfonic acid presents relevant antifungal activity. However, its intrinsic acidity could lead to an ionization process, decreasing fungal cell permeability.

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Doxorubicin (Dox) clinical use is limited by dose-related cardiomyopathy, becoming more prevalent with increasing cumulative doses. Previously, we developed Dox-loaded lipid-core nanocapsules (Dox-LNC) and, in this study, we hypothesized that self-assembling and interfacial reactions could be used to obtain arginylglycylaspartic acid (RGD)-surface-functionalized-Dox-LNC, which could target tumoral cells overexpressing αvβ3 integrin. Human breast adenocarcinoma cell line (MCF-7) and human glioblastoma astrocytoma (U87MG) expressing different levels of αvβ3 integrin were studied.

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In the title compound, CHO, obtained from the acyl-ation reaction between 2,3--iso-propyl-idene-d-ribono-1,4-lactone and benzoyl chloride, the known absolute configuration for the lactone moiety of the ester substituent has been confirmed. The five-membered rings of the bicyclic lactone-dioxolane moiety both show envelope conformations and form a dihedral angle of 19.82 (7)° between the lactone ring and the benzene ring.

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The absolute configuration, (3a,3'a,7a,7'a), of the title compound, CHO, synthesized a palladium-catalyzed homocoupling reaction, was determined on the basis of the synthetic pathway and was confirmed by X-ray diffraction. The homocoupled mol-ecule is formed by two chemically identical moieties built up from two five- and six-membered fused rings. The supra-molecular assembly is controlled mainly by C-H⋯O inter-actions that lead to the formation of hydrogen-bonded chains of mol-ecules along the [001] direction, while weak dipolar inter-actions and van der Waals forces hold the chains together in the crystal structure.

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The formulation that the title compound, C18H18N2O4S2, adopts is a zwitterionic core with the charge separated to the sulfilimine S and N atoms and is supported by the two different S-N bond distances about the sulfinimine N atom [1.594 (2) and 1.631 (2) Å, respectively] that are typical for such bonds.

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Purpose: To investigate the prevalence of human papillomavirus (HPV) in cervical samples of pregnant and non-pregnant women in South-Brazil.

Methods: A prospective study of 91 pregnant and 92 non-pregnant women with no previous history of cervical dysplasia or cancer was carried out. Cervical samples for HPV testing and cytology were collected in each trimester of pregnancy and in the puerperium for pregnant women and at matched intervals for the non-pregnant women.

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The absolute structure of the chiral asymmetric indole precursor title compound, C11H13NO3S, was confirmed by refinement of the Flack and Hooft parameters and is that expected based on the starting materials for the synthesis. The phenyl group subtends a dihedral angle of 56.40 (5)° with the mean plane of the oxazolidinone ring, which adopts an envelope conformation, with the C atom bearing the methyl group as the flap.

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The first examples of dihydro-1H-benzindoles by enantioselective γ-lactamization reaction of naphthyl sulfilimines with trichloroacetyl chloride in the presence of ZnCu as catalyst (≥98:2 er and 65-80% yields) are described. Products are obtained by [3,3]-sigmatropic rearrangement of the azasulfonium enolate or followed by a second allylic rearrangement that transfers chirality. The absolute stereochemistry was confirmed by X-ray crystallography, which provides support for the mechanisms proposed.

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TB is a global public health emergency in which new drugs are desperately needed. Herein we report on the synthesis of a diverse panel of 41 aryl allylic azides, thiocyanates, isothiouronium salts, and N,N'-diacetylisothioureas that were evaluated for their in vitro activity against replicating and non-replicating Mycobacterium tuberculosis (Mtb) H(37)Rv and toxicity to VERO cells. We found a selective group of new and promising compounds having good (micromolar) to excellent (sub-micromolar) potency against replicating Mtb H(37)Rv.

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Purpose: to demonstrate the expression of biomarkers, detected by immunohistochemical techniques in healthy tissues, as well as in preneoplastic and neoplastic lesions of the uterine cervix.

Methods: in order to evaluate the immunohistochemical reactivity of tissues from the uterine cervix to p16 and to type 2 herpes simplex virus (HSV-2), 187 samples of low-grade intraepithelial lesions (LG-IEL) and high-grade intraepithelial lesions (HG-IEL), and of uterine cervix carcinoma were compared with a group of patients without uterine cervix lesions. Statistical analysis was done by the chi2 test for trends.

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Objective: To evaluate immunohistochemical, hysteroscopic, and histological findings in postmenopausal women taking tamoxifen for breast cancer.

Methods: Forty postmenopausal women taking 20 mg/day tamoxifen for breast cancer underwent hysteroscopy and endometrial biopsy from January 2000 to December 2003. Medical records and paraffin blocks were analyzed retrospectively, and Ki-67, estrogen receptors (ERs), and progesterone receptors were measured using an immunohistochemical technique.

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Hydrolysis of DNA is of increasing importance in biotechnology and medicine. In this Letter, we present the DNA-cleavage potential of metal-free hydroxylamines and oximes as new members of nucleic acid cleavage agents.

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