Three-Dimensional Correlative Imaging of a Malaria-Infected Cell with a Hard X-ray Nanoprobe.

Benefiting from the recent advances of synchrotron X-ray nanoprobes, we demonstrate three-dimensional (3D) correlative nanoimaging on malaria-infected human red blood cells. By combining X-ray fluorescence tomography and phase contrast nanotomography on the same cell with sub-100 nm pixel size, we establish a routine workflow from the data acquisition, data processing, to tomographic reconstruction. We quantitatively compare the elemental volumes obtained with different reconstruction methods, with the total variation minimization giving the most satisfactory results. We reveal elemental correlations in different cell compartments more reliably on reconstructions as opposed to 2D projections. Finally, we determine for the first time the 3D mass fraction maps of multiple elements at the subcellular level. The estimated total number of Fe atoms and the total mass of red blood cells show very good agreement with previously reported values.

New heterocyclic compounds: Synthesis and antitrypanosomal properties.

Three new series of quinoline, quinolone, and benzimidazole derivatives were synthesized and evaluated in vitro against Trypanosoma brucei gambiense. In the quinoline series, the metallo antimalarial drug candidate (ferroquine, FQ) and its ruthenium analogue (ruthenoquine, RQ, compound 13) showed the highest in vitro activities with IC50 values around 0.1 µM. Unfortunately, both compounds failed to cure Trypanosoma brucei brucei infected mice in vivo. The other heterocyclic compounds were active in vitro with IC50 values varying from 0.8 to 34 µM. One of the most interesting results was a fluoroquinolone derivative (compound 2) that was able to offer a survival time of 8 days after a treatment at the single dose of 100 µmol/kg by intraperitoneal route. Although no clear-cut structure-activity relationships emerged, further pharmacomodulations are worth to be developed in this series.

Antiprotozoal activity of ferroquine.

Ferroquine (FQ, SSR97193) is a synthetic compound currently in development for the treatment of malaria. The use of a single compound to treat several parasitoses would be very convenient for multi-infected patients and also for financial considerations. In this work, the activity of FQ was investigated on three other Protista parasites: Kinetoplastidae (Leishmania and Trypanosoma) and the cosmopolite parasite Trichomonas vaginalis. FQ exhibited a significant in vitro activity on Trypanosoma brucei brucei and Trypanosoma brucei gambiense, the agents of African trypanosomiasis in a range from 0.2 to 3.1 µM. In vivo, intraperitoneally administered FQ demonstrated a weak but significant trypanocidal activity at 100 µmol/kg, which is however higher than the maximum tolerated dose. The drop of the parasitemia of the treated mice was significantly related to the amount of injected FQ. Furthermore, this organometallic compound was responsible for a delay in the appearance of bloodstream parasites at 50 µmol/kg. However, it was not able to cure infected mice. Although no synergy was identified in vitro between FQ and pentamidine, these results justify further investigations by evaluating analogues in this chemical series.

The antimalarial ferroquine: from bench to clinic.

Ferroquine (FQ, SSR97193) is currently the most advanced organo-metallic drug candidate and about to complete phase II clinical trials as a treatment for uncomplicated malaria. This ferrocene-containing compound is active against both chloroquine-susceptible and chloroquine-resistant Plasmodium falciparum and P. vivax strains and/or isolates. This article focuses on the discovery of FQ, its antimalarial activity, the hypothesis of its mode of action, the current absence of resistance in vitro and recent clinical trials.

A sequential bioorthogonal dual strategy: ManNAl and SiaNAl as distinct tools to unravel sialic acid metabolic pathways.

Recent methodological developments in metabolic oligosaccharide engineering (MOE) pave the way for tremendous advances in glycobiology. Herein, we propose a Sequential Bioorthogonal Dual Strategy (SBDS) combining the use of two unprotected alkyne-tagged monosaccharide reporters (ManNAl and SiaNAl) with the bioligation of fluorescent probes by copper-catalysed azide-alkyne cycloaddition (CuAAC). With SBDS, we are able to shed light on trafficking and cellular uptake mechanisms of sialic acid. Using their corresponding analogues, we visualized that SiaNAl enters via endocytosis, whereas its biosynthetic intermediate ManNAl uptake is mediated by a yet unknown but specific plasma membrane transporter. Sialin, a lysosomal protein, is shown to be crucial for the export of exogenous sialic acid from lysosomes to the cytosol. Metabolic labeling with alkyne-tagged derivatives of N-acetylneuraminic acid (Neu5Ac) or N-acetylmannosamine (ManNAc) could thus be used to follow endocytosis in physiological vs. pathological conditions.

Synthesis and antimalarial activity in vitro and in vivo of a new ferrocene-chloroquine analogue.

The antimalarial activities of ferrocenic compounds mimicking chloroquine and active upon chloroquine-resistant strains of Plasmodium falciparum were evaluated. Four 7-chloro-4-[[[2-[(N,N-substituted amino)methyl]ferrocenyl]methyl]amino]quinoline derivatives have been synthesized; one of them, 1a, showed high potent antimalarial activity in vivo on mice infected with Plasmodium berghei N. and Plasmodium yoelii NS. and was 22 times more potent against schizontocides than chloroquine in vitro against a drug-resistant strain of P. falciparum.

A prodrug form of a Plasmodium falciparum glutathione reductase inhibitor conjugated with a 4-anilinoquinoline.

Glutathione (GSH), which is known to guard Plasmodium falciparum from oxidative damage, may have an additional protective role by promoting heme catabolism. An elevation of GSH content in parasites leads to increased resistance to chloroquine (CQ), while GSH depletion in resistant P. falciparum strains is expected to restore the sensitivity to CQ. High intracellular GSH levels depend inter alia on the efficient reduction of GSSG by glutathione reductase (GR). On the basis of this hypothesis, we have developed a new strategy for overcoming glutathione-dependent 4-aminoquinoline resistance. To direct both a 4-aminoquinoline and a GR inhibitor to the parasite, double-drugs were designed and synthesized. Quinoline-based alcohols (with known antimalarial activity) were combined with a GR inhibitor via a metabolically labile ester bond to give double-headed prodrugs. The biochemically most active double-drug 7 of this series was then evaluated as a growth inhibitor against six Plasmodium falciparum strains that differed in their degree of resistance to CQ; the ED(50) values for CQ ranged from 14 to 183 nM. While the inhibitory activity of the original 4-aminoquinoline-based alcohol followed that of CQ in these tests, the double-drug exhibited similar efficiency against all strains, the ED(50) being as low as 28 nM. For the ester 7, a dose-dependent decrease in glutathione content and GR activity and an increase in glutathione-S-transferase activity were determined in treated parasites. The drug was subsequently tested for its antimalarial action in vivo using murine malaria models infected with P. berghei. A 178% excess mean survival time was determined for the animals treated with 40 mg/kg 7 for 4 days. No cytotoxicity due to this compound was observed. Work is in progress to extend and validate the strategy outlined here.

Synthetic ferrocenic mefloquine and quinine analoguesas potential antimalarial agents.

A few years ago we proposed a strategy for the synthesis of new ferrocene-chloroquine analogues replacing the carbon chain of chloroquine by hydrophobic ferrocenyl moieties. Now, this strategy has been applied to the antimalarial amino-alcohols class to afford new potentially active analogues of mefloquine and quinine bearing a substituted ferrocenic group. The pathway used for the synthesis of the mefloquine analogues includes the coupling of an aminomethyl substituted ferrocene carboxaldehyde with a lithio quinoline compound. On the other hand, the synthesis of quinine analogues was ensured by the 'inverse' reaction of a lithio aminomethyl ferrocene with a quinoline carboxaldehyde. The configurations of each diastereoisomer were unambiguously determined by spectroscopic data. The mechanistic interpretations were fully discussed. Ferrocenyl analogues of mefloquine and quinine exhibited a lower antimalarial activity than mefloquine and quinine themselves. Comparing optical isomers, those isomers dissimilar to ferrocenyl derivatives presented better antimalarial activities than those similar to ferrocenyl.

[Mesenteric panniculitis with retroperitoneal involvement resolved after treatment with intravenous cyclophosphamide pulses]. / Paniculitis mesentérica con afectación retroperitoneal resuelta tras tratamiento con pulsos de ciclofosfamida endovenosa.

Mesenteric panniculitis is an inflammatory process of the adipose tissue of the mesentery. It produces a thickening of the mesentery of the small bowel or colon and can occasionally involve the retroperitoneum. It is characterized by an infiltration of lipid-laden macrophages and associated with variable degrees of inflammation and fibrosis. Several treatments have been used, including colchicine, dapsone, corticosteroids associated or not with immunosuppressants, but there are no prospective controlled studies to define appropriate treatment: moreover, there are cases of regression without specific therapy. We present the case of a patient with mesenteric panniculitis affecting the colon and retroperitoneal space including the right ureter and iliac vein. Immunosuppressive treatment with monthly intravenous pulse cyclophosphamide and oral corticosteroids, resulted in the disappearance of the abdominal mass without relapse during ten months of monitoring.

Organometallic complexes: new tools for chemotherapy.

The importance of organometallics can be noticed by their presence in all life organisms. The most known natural organometallic molecule is vitamin B12, a porphyrin containing a cobalt atom, useful for several enzymatic transformations. Based on the remarkable properties of this class of compounds, a new area of medicinal research was developed. Gérard Jaouen was the first to introduce the term of "bioorganometallic chemistry" in 1985 although the first organometallic therapeutical was Salvarsan®, discovered by Paul Ehrlich (Nobel Prize in Medicine in 1908). Bioorganometallic chemistry consists of the synthesis and the study of organometallic complexes, complexes with at least one metal-carbon bond, in a biological and medicinal interest. This field of research was accentuated by the discovery of the ferrocene in 1951 by Pauson and Kealy, confirmed in 1952 by Wilkinson (Nobel Prize in 1973). Today, bioorganometallic chemistry includes 5 main domains: (1) organometallic therapeuticals, (2) toxicology and environment, (3) molecular recognition in aqueous phases, (4) enzymes, proteins and peptides, (5) bioanalysis and pharmaceutical sensors. In this review, we focused on organometallic therapeuticals. The exceptional properties of organometallics are first described and then, an overview on the main organometallic complexes used for drug design is presented. This review gives an idea how organometallics can be used for the rational design of new drugs.

Synthesis and antifungal activity of a ferrocene-fluconazole analogue.

A novel ferrocene fluconazole analogue was synthesized and its antifungal properties investigated against yeast strains of medical importance, including those intrinsically resistant to fluconazole. In vitro tests revealed a slight increase in fungal growth and a reversal of the effect of fluconazole at minimal inhibitory concentrations.

Synthesis and antimalarial activity in vitro of potential metabolites of ferrochloroquine and related compounds.

In man, the two major metabolites of the antimalarial drug chloroquine (CQ) are monodesethylchloroquine (DECQ) and didesethylchloroquine (di-DECQ). By analogy with CQ, the synthesis and the in vitro tests of some amino derivatives of ferrochloroquine (FQ), a ferrocenic analogue of CQ which are presumed to be the oxidative metabolites of FQ, are reported. Desmethylferrochloroquine 1a and didesmethylferrochloroquine 2 would be more potent against schizontocides than CQ in vitro against two strains (HB3 and Dd2) of Plasmodium falciparum. Other secondary amino derivatives have been prepared and proved to be active as antimalarial agents in vitro, too.

In vitro and in vivo antimalarial activity of ferrochloroquine, a ferrocenyl analogue of chloroquine against chloroquine-resistant malaria parasites.

Previous studies have shown that ferrochloroquine (FQ) exhibited an antimalarial activity against Plasmodium spp. The present work confirmed this activity, described the curative effect on P. vinckei and investigated the FQ toxicity in vitro and in vivo. The in vitro and in vivo growth inhibition of P. falciparum and P. berghei N, respectively, showed that FQ antimalarial activity was 1.5-10 times more potent than chloroquine. FQ completely inhibited the in vivo development of both chloroquine-susceptible and resistant P. vinckei strains and protected mice from lethal infection at a dose of 8.4 mg kg(-1) day(-1) given for 4 days subcutaneously or orally. This curative effect was 5-20 times more potent than chloroquine, according to the strains' resistance to chloroquine. At this curative dose, no clinical changes were observed in mice up to 14 days after the last administration. Nevertheless, the acute toxicity and lethality of ferrochloroquine seemed to be dependent on gastric surfeit. The FQ security index determined in vitro confirmed that it might be a promising compound.

[Fever of unknown origin in patients infected with the human immunodeficiency virus]. / Fiebre de origen desconocido en pacientes infectados por el virus de la inmunodeficiencia humana.

BACKGROUND: To describe the clinical features and the final diagnosis of patients infected with human immunodeficiency virus who presented fever of unknown origin. METHODS: Retrospective study, from November 1989 to January 1994, of all patients infected with HIV who had fever of unknown origin and who were admitted to a community hospital in a Mediterranean area in Alicante (Spain). Fever of unknown origin was defined as fever exceeding 38.3 degrees C lasting for at least three weeks with no diagnosis in the first three days of hospitalization after fulfilling clinical exam, three blood cultures, acid-fast bacilli stain in sputum and chest-X-ray. RESULTS: Of a cohort of 231 patients, 27 (12%) were evaluated because of fever of unknown origin during their follow-up. Patients' mean age was 31 years (interval, 22-75) and intravenous drug use (81%) was the most common risk factor for HIV infection. A total of 31 episodes of fever of unknown origin were reviewed. Twenty-three (74%) episodes occurred in patients with less than 200 CD4 lymphocytes/mm3. A final diagnosis of fever of unknown origin was achieved in 24 (77%) episodes: visceral leishmaniasis (n = 11), tuberculosis (n = 9), non-Hodgkin's lymphoma (n = 1), CNS toxoplasmosis (n = 1), cryptococcal meningitis (n = 1) and drug adverse reaction (n = 1). CONCLUSIONS: HIV-infected patients with fever of unknown origin very often show severe immunodeficiency. Cryptococcal antigen testing should be carried out in the initial evaluation of fever of unknown origin in HIV-infected patients. In our area, 64% of episodes of fever of unknown origin were caused by visceral leishmaniasis or tuberculosis.

In vitro antimalarial activity of a new organometallic analog, ferrocene-chloroquine.

The in vitro activities of new organometallic chloroquine analogs, based on 4-amino-quinoleine compounds bound to a molecule of ferrocene, were evaluated against chloroquine-susceptible, chloroquine-intermediate, and chloroquine-resistant, culture-adapted Plasmodium falciparum lineages by a proliferation test. One of the ferrocene analogs totally restored the activity of chloroquine against chloroquine-resistant parasites. This compound, associated with tartaric acid for better solubility, was highly effective. The role of the ferrocene in reversing chloroquine resistance is discussed, as is its potential use for human therapy.