Dithiocarbazate complexes with the [M(PPh(3))](2+) (M=Pd or Pt) moiety Synthesis, characterization and anti-Tripanosoma cruzi activity

New neutral Pd(II) and Pt(II) complexes of the type [M(L)(PPh(3))] (M Pd or Pt) were prepared in crystalline form in high-yield synthesis with the S-benzyldithiocarbazates and S-4-nitrobenzyldithiocarbazates derivatives from 2-hydroxyacetophenone, H(2)L(1a) and H(2)L(1b), and benzoylacetone, H(2)L(2a) and H(2)L(2b). The new complexes [Pt(L(1a))(PPh(3))] (1), [Pd(L(1a))(PPh(3))] (2), [Pt(L(1b))(PPh(3))] (3), [Pd(L(1b))(PPh(3))] (4), [Pt(L(2a))(PPh(3))] (5), [Pd(L(2a))(PPh(3))] (6), [Pt(L(2b))(PPh(3))] (7) and [Pd(L(2b))(PPh(3))] (8) were characterized on the basis of elemental analysis, conductivity measurements, UV-visible, IR, electrospray ionization mass spectrometry (ESI-MS), NMR ((1)H and (31)P) and by X-ray diffraction studies. The studies showed that differently from what was observed for the H(2)L(1a) and H(2)L(1b) ligands, H(2)L(2a) and H(2)L(2b) assume cyclic forms as 5-hydroxypyrazolinic. Upon coordination, H2L2a and H2L2b suffer ring-opening reaction, coordinating in the same manner as H(2)L(1a) and H(2)L(1b), deprotonated and in O,N,S-tridentate mode to the (MPPh(3))(2+) moiety. All complexes show a quite similar planar fourfold environment around the M(II) center. Furthermore, these complexes exhibited biological activity on extra and intracellular forms of Trypanosoma cruzi in a time- and concentration-dependent manner with IC(50) values ranging from 7.8 to 18.7 mu M, while the ligand H(2)L(2a) presented a trypanocidal activity on trypomastigote form better than the standard drug benznidazole. (C) 2010 Elsevier Inc. All rights reserved.

Antimycobacterial and antitumor activities of Palladium(II) complexes containing isonicotinamide (isn): X-ray structure of trans-[Pd(N(3))(2)(isn)(2)]

Complexes of the type trans-[PdX(2)(isn)(2)] {X = Cl (1), N(3) (2), SCN (3), NCO (4); isn = isonicotinamide} were synthesized and evaluated for in vitro antimycobacterial and antitumor activities. The coordination mode of the isonicotinamide and the pseudohalide ligands was inferred by IR spectroscopy. Single crystal X-ray diffraction determination on 2 showed that coordination geometry around Pd(II) is nearly square planar, with the ligands in a trans configuration. All the compounds demonstrated better in vitro activity against Mycobacterium tuberculosis than isonicotinamide and pyrazinamide. Among the complexes, compound 2 was found to be the most active with MIC of 35.89 mu M. Complexes 1-4 were also screened for their in vitro antitumor activity towards LM3 and LP07 murine cancer cell lines. (C) 2010 Elsevier Masson SAS. All rights reserved.

Pt(II) and Ag(I) complexes with acesulfame: Crystal structure and a study of their antitumoral, antimicrobial and antiviral activities

Two new complexes of platinum(II) and silver(I) with acesulfame were synthesized. Acesulfame is in the anionic form acesulfamate (ace). The structures of both complexes were determined by X-ray crystallography. For K(2)[PtCl(2)(ace)(2)] the platinum atom is coordinated to two Cl(-) and two N-acesulfamate atoms forming a trans-square planar geometry. Each K(+) ion interacts with two oxygen atoms of the S(=O)(2) group of each acesulfamate. For the polymeric complex [Ag(ace)](n) the water molecule bridges between two crystallographic equivalent Agl atoms which are related each other by a twofold symmetry axis. Two Agl atoms, related to each other by a symmetry centre, make bond contact with two equivalent oxygen atoms. These bonds give rise to infinite chains along the unit cell diagonal in the ac plane. The in vitro cytotoxic analyses for the platinum complex using HeLa (human cervix cancer) cells show its low activity when compared to the vehicle-treated cells. The Ag(I) complex submitted to in vitro antimycobacterial tests, using the Microplate Alamar Blue (MABA) method, showed a good activity against Mycobacterium tuberculosis, responsible for tuberculosis, with a minimal inhibitory concentration (MIC) value of 11.6 mu M. The Ag(I) complex also presented a promising activity against Gram negative (Escherichia colt and Pseudomonas aeruginosa) and Gram positive (Enterococcus faecalis) microorganisms. The complex K(2)[PtCl(2)(ace)(2)] was also evaluated for antiviral properties against dengue virus type 2 (New Guinea C strain) in Vero cells and showed a good inhibition of dengue virus type 2 (New Guinea G strain) replication at 200 mu M, when compared to vehicle-treated cells. (C) 2010 Elsevier Inc. All rights reserved.

Novel immunoadjuvants based on cationic lipid: Preparation, characterization and activity in vivo

The interactions between three different protein antigens and dioctadecyldimethylammonium bromide (DODAB) dispersed in aqueous solutions from probe sonication or adsorbed its one bilayer onto particles was comparatively investigated. The three model proteins were bovine serum albumin (BSA), purified 18 kDa/14 kDa antigens from Taenia crassiceps (18/14-Tcra) and a recombinant, heat-shock protein hsp-18 kDa from Mycobacterium leprae. Protein-DODAB complexes in water solution were characterized by dynamic light scattering for sizing and zeta-potential analysis. Cationic complexes (80-100 nm of mean hydrodynamic diameter) displayed sizes similar to those of DODAB bilayer fragments (BF) in aqueous solution and good colloid stability over a range of DODAB and protein concentrations. The amount of cationic lipid required for attaining zero of zeta-potential at a given protein amount depended on protein nature being smaller for 18 kDa/14 kDa antigens than for BSA. Mean diameters for DODAB/protein complexes increased, whereas zeta-potentials decreased with NaCl or protein concentration. In mice, weak IgG production but significant cellular immune responses were induced by the complexes in comparison to antigens alone or carried by aluminum hydroxide as shown from IgG in serum determined by ELISA, delayed type hypersensitivity reaction from footpad swelling tests and cytokines analysis. The novel cationic adjuvant/protein complexes revealed good colloid stability and potential for vaccine design at a reduced DODAB concentration. (C) 2009 Elsevier Ltd. All rights reserved.

Design of novel antituberculosis compounds using graph-theoretical and substructural approaches

The increasing resistance of Mycobacterium tuberculosis to the existing drugs has alarmed the worldwide scientific community. In an attempt to overcome this problem, two models for the design and prediction of new antituberculosis agents were obtained. The first used a mixed approach, containing descriptors based on fragments and the topological substructural molecular design approach (TOPS-MODE) descriptors. The other model used a combination of two-dimensional (2D) and three-dimensional (3D) descriptors. A data set of 167 compounds with great structural variability, 72 of them antituberculosis agents and 95 compounds belonging to other pharmaceutical categories, was analyzed. The first model showed sensitivity, specificity, and accuracy values above 80% and the second one showed values higher than 75% for these statistical indices. Subsequently, 12 structures of imidazoles not included in this study were designed, taking into account the two models. In both cases accuracy was 100%, showing that the methodology in silico developed by us is promising for the rational design of antituberculosis drugs.

Ruthenium (II) phosphine/picolinate complexes as antimycobacterial agents

The synthesis, characterization and the anti-Mycobacterium tuberculosis (MTB) activities of three ruthenium complexes containing the 2-pyridinecarboxylic acid anion (picolinate), with formulae cis-[Ru(pic)(dppm)(2)]PF(6) (1), Cis- [Ru(pic)(dppe)(2)]PF(6) (2) and [Ru(pic)(2)(PPh(3))(2)] (3) [pic = 2-pyridinecarboxylate; dppm = bis(diphenylphosphino)methane: dppe = 1,2-bis(diphenylphosphino)ethane; PPh(3) = triphenylphosphine] are reported in this article. The complexes were characterized by elemental analysis, spectroscopic and electrochemical techniques. Their in vitro anti mycobacterial activity was determinated as the Minimum Inhibitory Concentration (MIC) for MTB cell growth, measured by the REMA method. The best MICs were found for complexes (1) and (2), with values of 0.78 and 0.26 mu g/mL, respectively. The results are comparable to or better than ""first line"" or ""second line"" drugs commonly used in the treatment of TB. (C) 2009 Elsevier Masson SAS. All rights reserved.

Community-based study on knowledge, attitude and practice on the mode of transmission, prevention and treatment of the Buruli ulcer in Ga West District, Ghana

Buruli ulcer disease (BUD), a devastating tropical disease caused by Mycobacterium ulcerans, occurs in more than 80% of the administrative districts of Ghana. To elucidate community perceptions and
understanding of the aetiology of BUD, attitudes towards Buruli patients and treatment-seeking behaviours, we conducted a survey with 504 heads of households and seven focus group discussions in Ga West District, Ghana. Although 67% of participants regarded BUD as a health problem, 53% did not know its cause. Sixteen per cent attributed the cause to drinking non-potable water, 8.1% mentioned poor personal hygiene or dirty surroundings, and 5.5% identified swimming or wading in ponds as a risk factor. About 5.2% thought that witchcraft and curses cause BUD, and 71.8% indicated that BU sufferers first seek treatment from herbalists and only refer to the hospital as a last resort. The main
reasons were prospects of prolonged hospital stay, cost of transport, loss of earnings and opportunity associated with parents attending their children’s hospitalization over extended period, delays in being
attended by medical staff, and not knowing the cause of the disease or required treatment. The level of acceptance of BUD sufferers was high in adults but less so in children. The challenge facing health workers is to break the vicious cycle of poor medical outcomes leading to poor attitudes to hospital treatment in the community. Because herbalists are often the first people consulted by those who contract the disease, they need to be trained in early recognition of the pre-ulcerative stage of Buruli lesions.

Synthesis of 2-oxo-16-(3', 4'-methylenedioxyphenyl)-trans-15-hexadecene

This work presents the progress made towards synthesizing 2-oxo-16-(3', 4'methylenedioxyphenyl)-trans-15-hexadecene, an antimycobacterial compound that was originally isolated from the leaves of Piper Sanctum. The hydrocarbon chain of the molecule was synthesized first by opening a 15-pentadecanolactone ring by means of HI, and performing an E2 elimination reaction on the molecule followed by an organolithium reaction with CH3Li. Hexadec-15-en-2-one that was afforded this way was later reacted with 5-bromobenzo[d][1,3]dioxole following the appropriate Heck reaction protocol that allows for the formation of a palladium catalyzed carbon-carbon bond. The modes of action of 2-oxo-16-(3', 4'-methylenedioxyphenyl)-trans-15hexadecene are comparable to the ones of rifampicin, a marketable drug that has been successfully used in the treatment of tuberculosis in the past. Additionally, this compound can serve as an intermediate towards the synthesis of 2-oxo-16-(3', 4' methylenedioxyphenyl)-hexadecane and 2-oxo-14-(3', 4' -methylenedioxyphenyl) tetradecane, both strong inhibitors of the growth of Mycobacterium tuberculosis. Lastly, due to Multi-Drug Resistant tuberculosis, there has been an increasing need to find alternative cures for tuberculosis. Therefore, the work on 2-qxo-16-(3', 4'methylenedioxyphenyl)-trans-15-hexadecene is not only chemically interesting but it is also biologically important.

Two-year combination antibiotic therapy with clarithromycin, rifabutin, and clofazimine for Crohn's disease

Background & Aims: Mycobacterium avium subspecies paratuberculosis has been proposed as a cause of Crohn’s disease. We report a prospective, parallel, placebo-controlled, double-blind, randomized trial of 2 years of clarithromycin, rifabutin, and clofazimine in active Crohn’s disease, with a further year of follow-up. Methods: Two hundred thirteen patients were randomized to clarithromycin 750 mg/day, rifabutin 450 mg/day, clofazimine 50 mg/day or placebo, in addition to a 16-week tapering course of prednisolone. Those in remission (Crohn’s Disease Activity Index ≤150) at week 16 continued their study medications in the maintenance phase of the trial. Primary end points were the proportion of patients experiencing at least 1 relapse at 12, 24, and 36 months. Results: At week 16, there were significantly more subjects in remission in the antibiotic arm (66%) than the placebo arm (50%; P = .02). Of 122 subjects entering the maintenance phase, 39% taking antibiotics experienced at least 1 relapse between weeks 16 and 52, compared with 56% taking placebo (P = .054). At week 104, the figures were 26% and 43%, respectively (P = .14). During the following year, 59% of the antibiotic group and 50% of the placebo group relapsed (P = .54). Conclusions: Using combination antibiotic therapy with clarithromycin, rifabutin, and clofazimine for up to 2 years, we did not find evidence of a sustained benefit. This finding does not support a significant role for Mycobacterium avium subspecies paratuberculosis in the pathogenesis of Crohn’s disease in the majority of patients. Short-term improvement was seen when this combination was added to corticosteroids, most likely because of nonspecific antibacterial effects.

The clp chaperones and proteases of the human malaria parasite Plasmodium falciparum

The Clp chaperones and proteases play an important role in protein homeostasis in the cell. They are highly conserved across prokaryotes and found also in the mitochondria of eukaryotes and the chloroplasts of plants. They function mainly in the disaggregation, unfolding and degradation of native as well as misfolded proteins. Here, we provide a comprehensive analysis of the Clp chaperones and proteases in the human malaria parasite Plasmodium falciparum. The parasite contains four Clp ATPases, which we term PfClpB1, PfClpB2, PfClpC and PfClpM. One PfClpP, the proteolytic subunit, and one PfClpR, which is an inactive version of the protease, were also identified. Expression of all Clp chaperones and proteases was confirmed in blood-stage parasites. The proteins were localized to the apicoplast, a non-photosynthetic organelle that accommodates several important metabolic pathways in P. falciparum, with the exception of PfClpB2 (also known as Hsp101), which was found in the parasitophorous vacuole. Both PfClpP and PfClpR form mostly homoheptameric rings as observed by size-exclusion chromatography, analytical ultracentrifugation and electron microscopy. The X-ray structure of PfClpP showed the protein as a compacted tetradecamer similar to that observed for Streptococcus pneumoniae and Mycobacterium tuberculosis ClpPs. Our data suggest the presence of a ClpCRP complex in the apicoplast of P. falciparum.

Influenza A virus infection impairs mycobacteria-specific T cell responses and mycobacterial clearance in the lung during pulmonary coinfection.

Individuals infected with mycobacteria are likely to experience episodes of concurrent infections with unrelated respiratory pathogens, including the seasonal or pandemic circulating influenza A virus strains. We analyzed the impact of influenza A virus and mycobacterial respiratory coinfection on the development of CD8 T cell responses to each pathogen. Coinfected mice exhibited reduced frequency and numbers of CD8 T cells specific to Mycobacterium bovis bacille Calmette-Guérin (BCG) in the lungs, and the IFN-γ CD8 T cell response to BCG-encoded OVA was decreased in the lungs of coinfected mice, when compared with mice infected with BCG alone. Moreover, after 2 wk of infection, mice coinfected with both pathogens showed a significant increase in the number of mycobacteria present in the lung compared with mice infected with BCG only. Following adoptive transfer into coinfected mice, transgenic CD8 T cells specific for OVA257–264 failed to proliferate as extensively in the mediastinal lymph nodes as in mice infected only with BCG-OVA. Also noted was a reduction in the proliferation of BCG-specific CD4 transgenic T cells in mice coinfected with influenza compared with mice infected with BCG alone. Furthermore, phenotypic analysis of CD11c+ dendritic cells from mediastinal lymph nodes of the infected mice showed that coinfection was associated with decreased surface expression of MHC class II and class I. Thus, concurrent pulmonary infection with influenza A virus is associated with decreased MHC expression on dendritic cells, reduced activation of BCG-specific CD4 and CD8 T cells, and impaired clearance of mycobacteria.

Forgotten but not gone - Scrofuloderma in a migrant student from India

A 34-year-old Indian student who immigrated to Australia five years ago presented with a four-week history of neck pain. Physical examination revealed two firm fixed cervical lymph nodes in the anterior triangle and midline region which were tender on palpation and erythematous on inspection. Cording phenomenon was found on ZN staining of FNA sample and mycobacterium tuberculosis (M.tb) PCR confirmed the diagnosis with incomplete resistance to isoniazid. Patient was treated with other three first line antituberculosis medications for nine months with an excellent outcome. Prednisolone was also used as adjunctive therapy and tapered during the course of treatment.

Novel 1,4-substituted-1,2,3-triazoles as antitubercular agents

Tuberculosis (TB) remains a pressing unmet medical need, particularly with the emergence of multidrug-resistant and extensively drug-resistant tuberculosis. Here, a series of 1,4-substituted-1,2,3-triazoles have been synthesized and evaluated as potential antitubercular agents. These compounds were assembled via click chemistry in high crude purity and in moderate to high yield. Of the compounds tested, 12 compounds showed promising antitubercular activity with six possessing minimum inhibitory concentration (MIC) values <10 μg mL^-1, and total selectivity for Mycobacterium tuberculosis (Mtb) growth inhibition. A second set of 21 compounds bearing variations on ring C were synthesized and evaluated. This second library gave an additional six compounds displaying MIC values ≤10 μg mL^-1 and total selectivity for Mtb growth inhibition. These compounds serve as an excellent starting point for further development of antitubercular therapies.