Proenkephalin deletion in hematopoietic cells induces intestinal barrier failure resulting in clinical feature similarities with irritable bowel syndrome in mice

Opioid-dependent immune-mediated analgesic effects have been broadly reported upon inflammation. In preclinical mouse models of intestinal inflammatory diseases, the local release of enkephalins (endogenous opioids) by colitogenic T lymphocytes alleviate inflammation-induced pain by down-modulating gut-innervating nociceptor activation in periphery. In this study, we wondered whether this immune cell-derived enkephalin-mediated regulation of the nociceptor activity also operates under steady state conditions. Here, we show that chimeric mice engrafted with enkephalin-deficient bone marrow cells exhibit not only visceral hypersensitivity but also an increase in both epithelial paracellular and transcellular permeability, an alteration of the microbial topography resulting in increased bacteria-epithelium interactions and a higher frequency of IgA-producing plasma cells in Peyer's patches. All these alterations of the intestinal homeostasis are associated with an anxiety-like behavior despite the absence of an overt inflammation as observed in patients with irritable bowel syndrome. Thus, our results show that immune cell-derived enkephalins play a pivotal role in maintaining gut homeostasis and normal behavior in mice. Because a defect in the mucosal opioid system remarkably mimics some major clinical symptoms of the irritable bowel syndrome, its identification might help to stratify subgroups of patients.

THEMIS enhances the magnitude of normal and neuroinflammatory type 1 immune responses by promoting TCR-independent signals

Signals that determine the differentiation of naïve CD4 + T helper (T H ) cells into specific effector cell subsets are primarily stimulated by cytokines, but additional signals are required to adjust the magnitude of T H cell responses and set the balance between effective immunity and immunological tolerance. By inducing the post-thymic deletion of the T cell lineage signaling protein THEMIS, we showed that THEMIS promoted the development of optimal type 1 immune responses to foreign antigens but stimulated signals that favored encephalitogenic responses to self-neuroantigens. THEMIS was required to stimulate the expression of the gene encoding the transcriptional regulator T-BET and the production of the cytokine interferon-γ (IFN-γ), and it enhanced the ability of encephalitogenic CD4 + T cells to migrate into the central nervous system. Consistently, analysis of THEMIS expression in polarized CD4 + T cells showed that THEMIS was selectively increased in abundance in T H 1 cells. The stimulation of predifferentiated effector CD4 + T cells with antigen-presenting cells revealed a stimulatory function for THEMIS on type 1 cytokine responses, similar to those observed ex vivo after immunization. In contrast, THEMIS exerted opposing effects on naïve CD4 + T cells in vitro by inhibiting the T cell receptor (TCR)–mediated signals that lead to T H 1 cell responses. These data suggest that THEMIS exerts TCR-independent functions in effector T cells, which increase the magnitude of normal and pathogenic T H 1 cell–mediated responses.

A selective LIS1 requirement for mitotic spindle assembly discriminates distinct T-cell division mechanisms within the T-cell lineage

The ability to proliferate is a common feature of most T-cell populations. However, proliferation follows different cell-cycle dynamics and is coupled to different functional outcomes according to T-cell subsets. Whether the mitotic machineries supporting these qualitatively distinct proliferative responses are identical remains unknown. Here, we show that disruption of the microtubule-associated protein LIS1 in mouse models leads to proliferative defects associated with a blockade of T-cell development after β-selection and of peripheral CD4+ T-cell expansion after antigen priming. In contrast, cell divisions in CD8+ T cells occurred independently of LIS1 following T-cell antigen receptor stimulation, although LIS1 was required for proliferation elicited by pharmacological activation. In thymocytes and CD4+ T cells, LIS1 deficiency did not affect signaling events leading to activation but led to an interruption of proliferation after the initial round of division and to p53-induced cell death. Proliferative defects resulted from a mitotic failure, characterized by the presence of extra-centrosomes and the formation of multipolar spindles, causing abnormal chromosomes congression during metaphase and separation during telophase. LIS1 was required to stabilize dynein/dynactin complexes, which promote chromosome attachment to mitotic spindles and ensure centrosome integrity. Together, these results suggest that proliferative responses are supported by distinct mitotic machineries across T-cell subsets.

Striatal Neurons Expressing D1 and D2 Receptors are Morphologically Distinct and Differently Affected by Dopamine Denervation in Mice

The loss of nigrostriatal dopamine neurons in Parkinson’s disease induces a reduction in the number of dendritic spines on medium spiny neurons (MSNs) of the striatum expressing D₁ or D₂ dopamine receptor. Consequences on MSNs expressing both receptors (D₁/D₂ MSNs) are currently unknown. We looked for changes induced by dopamine denervation in the density, regional distribution and morphological features of D₁/D₂ MSNs, by comparing 6-OHDA-lesioned double BAC transgenic mice (Drd1a-tdTomato/Drd2-EGFP) to sham-lesioned animals. D₁/D₂ MSNs are uniformly distributed throughout the dorsal striatum (1.9% of MSNs). In contrast, they are heterogeneously distributed and more numerous in the ventral striatum (14.6% in the shell and 7.3% in the core). Compared to D₁ and D₂ MSNs, D₁/D₂ MSNs are endowed with a smaller cell body and a less profusely arborized dendritic tree with less dendritic spines. The dendritic spine density of D₁/D₂ MSNs, but also of D₁ and D₂ MSNs, is significantly reduced in 6-OHDA-lesioned mice. In contrast to D₁ and D₂ MSNs, the extent of dendritic arborization of D₁/D₂ MSNs appears unaltered in 6-OHDA-lesioned mice. Our data indicate that D₁/D₂ MSNs in the mouse striatum form a distinct neuronal population that is affected differently by dopamine deafferentation that characterizes Parkinson’s disease.

[Pomalidomide for multiple myeloma]

Once characterized by a very poor outcome, multiple myeloma (MM) now has a significantly prolonged survival, with major improvements allowed by the use of "novel agents": proteasome inhibitors (first-in-class bortezomib) and immunomodulatory compounds (IMiDs; first-in-class thalidomide and lenalidomide). However, the vast majority - if not all - of patients with MM ultimately end up being refractory to all existing drugs, including these efficient novel agents. There is a clear unmet medical need in this situation, which warrants the development of the next generation of proteasome inhibitors and IMiDs, as well as new drug classes. This review focuses on pomalidomide, the next generation IMiD, recently approved by the US FDA and the EMA for patients with relapsed or refractory MM who have received at least two prior therapies, including lenalidomide and bortezomib, and have demonstrated disease progression on their last therapy.

Antileishmanial activity of a formulation of 2-n-propylquinoline by oral route in mice model

2-n-propylquinoline is presently a drug-candidate for the treatment of visceral leishmaniosis in pre-clinical development. As this compound is in an oily state, it needs to be formulated and the objectives of this study are: to prepare a formulation; to demonstrate that the new salted formulation did not alter the activity of the active ingredient; and finally, that this activity was quite good compared to the reference oral drug, miltefosine. Therefore, a 2-n-propylquinoline formulation, as camphorsulfonic salt, was prepared and characterised. On the Leishmania donovani / Balb/c mice model, a treatment by oral route at 60 μmoles/kg/day for ten consecutive days with this formulation was compared to 2-n-propylquinoline alone and to miltefosine, the oral reference drug. The salt formulation did not alter the activity of the 2-n-propylquinoline. The formulation reduced the parasite burden of 76% compared to 89% for miltefosine (not significant). The characteristics of this formulation results in a suitable drugability of 2-n-propylquinoline for further studies.

In vitro antileishmanial and antitrypanosomal activities of five medicinal plants from Burkina Faso

After ethnobotanical surveys in central and western regions of Burkina Faso, five plants namely Lantana ukambensis (Verbenaceae), Xeoderris sthulmannii (Fabaceae), Parinari curatellifollia (Chrysobalanaceae), Ozoroa insignis (Anacardiaceae), and Ficus platyphylla (Moraceae) were selected for their traditional use in the treatment of parasitic diseases and cancer. Our previous studies have focused on the phytochemical, genotoxicity, antioxidant, and antiproliferative activities of these plants. In this study, the methanol extract of each plant was tested to reveal probable antileishmanial and antitrypanosomal activities. Colorimetric and spectrophotometric methods were used for the detection of antileishmanial and antitrypanosomal activities. Leishmania donovani (LV9 WT) and Trypanosoma brucei brucei GVR 35 were used to test the antileishmanial and antitrypanosomal activities, respectively. All extracts of tested plants showed a significant antitrypanosomal activity with minimum lethal concentrations between 1.5 and 25 μg/ml, the L. ukambensis extract being the most active. In the antileishmanial test, only the extract from L. ukambensis showed significant activity with an inhibitory concentration (IC(50)) of 6.9 μg/ml. The results of this study contribute to the promotion of traditional medicine products and are preliminary for the isolation of new natural molecules for the treatment of leishmaniasis and trypanosomiasis.

Membrane sterol depletion impairs miltefosine action in wild-type and miltefosine-resistant Leishmania donovani promastigotes

OBJECTIVES

This study focuses on the importance of sterols in the action of miltefosine (hexadecylphosphocholine, HePC) against Leishmania donovani.

METHODS

Plasma membranes of L. donovani promastigotes were depleted of sterol using methyl-beta-cyclodextrin (MCD) and cholesterol oxidase (CH-OX). Sterols were quantified and HePC susceptibility was assessed using the MTT test. A biomimetic model of the outer leaflet of a Leishmania plasma membrane was used to decipher the HePC-lipid interactions.

RESULTS

CH-OX, which is known to act more specifically on condensed membranes, therefore at the level of lipid rafts, gave a better extraction yield in HePC-resistant parasites, confirming the more rigid structure of their membranes than those of wild-type parasites. Sterol depletion was responsible for a 40% decrease in HePC susceptibility in both wild-type and HePC-resistant parasites. Sterol repletion of the sterol-depleted parasites restored HePC susceptibility. The biomimetic model of the outer leaflet of a Leishmania plasma membrane confirmed that condensed microdomains were able to incorporate higher quantities of HePC than fluid ones and this result was amplified when the sterol concentration was increased.

CONCLUSIONS

Sterol and lipid rafts probably play a significant role as an HePC reservoir providing a constant supply to the previously described transporter. In addition, (1)H NMR experiments suggested that HePC stimulated lipid trafficking in parasites.

Nosocomial dermatitis caused by Dermanyssus gallinae

The mite Dermanyssus gallinae may cause pruritic dermatitis in humans. We describe a case of nosocomial infestation with D. gallinae from an abandoned pigeon nest suspended on the front wall of the Hôpital Henri Mondor near a window. Close surveillance and regular destruction of pigeon nests could prevent these incidents of infection in humans.

Postnatal electrical and morphological abnormalities in lumbar motoneurons from transgenic mouse models of amyotrophic lateral sclerosis

Antidromically identified lumbar motoneurons intracellularly recorded in the entire brainstem/spinal cord preparation isolated from SOD1(G85R) postnatal mice (P3-P10) were labelled with neurobiotin and fully reconstructed in 3D from serial sections in order to analyse their morphology. This staining procedure revealed differences between WT and SOD1(G85R) dendritic trees for most metric and topologic parameters analyzed. A highly complex morphology of SOD1(G85R) motoneurons dendrites (increased number of branching points and terminations) was found and the dendritic trees were longer compared to the WT motoneurons. These morphological changes observed in P8-P9 motoneurons mice occurred concomitantly with a decrease in the input resistance and gain. During electrophysiological recordings, four patterns of discharge were observed in response to ramp stimulations, that were equally distributed in WT and SOD1(G85R) motoneurons. In slice preparation, whole cell patch-clamp recordings made from developing motoneurons in SOD1(G85R) and double transgenic SOD1(G93A)/Hb9-eGFP mice showed that Riluzole, a blocker of persistent inward sodium conductance, altered the repetitive firing in a similar way for the 2 strains. These results show that the SOD1 mutations linked to familial ALS alter the development of the electrical and morphological properties of lumbar motoneurons.

Recent strategies for the chemotherapy of visceral leishmaniasis

Visceral leishmaniasis is a widespread and deadly disease. First-line drugs are antimonials, but amphotericin B and its lipid formulations B is used for treating visceral leishmaniasis that is unresponsive to antimony. New therapeutic approaches are being actively developed, including the following: use of drug carriers targeted specifically to the parasite location, thus reduce adverse effects of drug; use of immunomodulating drugs; evaluation of natural products; pharmacokinetic studies; and drug combinations. Recent clinical trials with paromomycin and miltefosine were successful and these drugs appear to be promising for the future therapy of visceral leishmaniasis. Furthermore, identification and therapeutic evaluation of specific targets in the Leishmania organism could lead to new compounds, such as antileishmanial drugs and reversal agents of drug resistance.

In vitro and in vivo antileishmanial efficacy of a new nitrilquinoline against Leishmania donovani

The in vitro activity of a new analogue of 2-alkenylquinoline (2-nitrilquinoline or NQ) against Leishmania donovani was compared to oral reference drug miltefosine (HePC). IC(50) of NQ was found at 38.6 microM against promastigotes and 2.4 microM against intramacrophage amastigotes. In vivo evaluation in the L. donovani Balb/c mice model indicated that oral treatments at 12.5 and 25 mg/kg for 10 consecutive days significantly reduced the parasite burden in the liver by 68.9 and 68.5%, respectively. This activity was similar to those of HePC at 7.5 mg/kg for 10 days which reduced the parasite burden in liver by 72.5%. The present study shows the positive contribution of a nitril substitute being added into the alkenyl chain branched at the 2-position of the quinoline ring to the antileishmanial activity. In addition, any apparent toxicological disorder was observed during the experiments.

[Antileishmanial activity of five 2- or 3- quinolines by enyne group]

INTRODUCTION

Leishmaniasis is an emergent orphan disease because of its co-infection with HIV AIDS. We report herein the in vitro biological evalution of five news quinolines, 2- or 3- substituted by an enyne group against Leishmania donovani (MHOM/ET/L82/LV9).

PATIENTS AND METHODS

The quinolines has been synthesized by using a cross-coupling reaction between a chloroenyne and an organometallic coumpound in a presence of iron a "green" catalyst. Biological evalution is realized by a colorimetric method with the use of 3-(4,5-dimethylthiazol-2,5-diphényl)-tétrazolium bromide.

RESULTS

Determination of the inhibitory concentrations as well as the minimal inhibitory concentrations has shown that the substitution by an enyne group made it possible to have a more important antileishmanial activity. In addition, we have seen that the -2 or the -3 position of the enyne group had no influence in the antileishmanial activity.

CONCLUSION

Thus, we have shown the real interest of these quinolines which could be favourably compared with pentamidine, which is currently the reference product, and to consider the use of these quinolines in the treament of the leishmaniasis.

Antileishmanial and trypanocidal activities of new miltefosine liposomal formulations

Liposomes composed of hexadecylphosphocholine/egg phosphatidylcholine/stearylamine (HePC/EPC/SA) 10:10:0.1, 10:10:0.5 and 10:10:1 (molar ratio) (1-3) were prepared and lyophilized. The liposomes were physicochemically characterized (size and zeta-potential) and they were found stable at 4 degrees C over a period of 4 weeks. In vitro, liposomes 1 and 2 were about twice more active than HePC against Leishmania donovani WT whereas liposomes 3 were about three times more active than HePC on HePC-resistant promastigotes. Although liposomes 1-3 were inactive on the in vitro intramacrophage amastigote model, the ability of the liposomes to accumulate within the liver where parasites are located justifies a further in vivo evaluation. We observed that liposome 1 was twice more active than HePC against Trypanosoma brucei brucei bloodstream forms maintained in vitro. In vivo results showed that liposomal HePC seemed to be less toxic than the free drug despite the absence of significant antitrypanosomal activity.

N-acetyl-β-d-hexosaminidase from Trichomonas vaginalis: substrate specificity and activity of inhibitors

Among chitinolytic activities previously described in Trichomonas vaginalis, N-acetyl-beta-D-hexosaminidase (NAHase) was the enzyme system expressing the highest level of specific activity. We report here some biochemical characteristics of NAHase purified from T. vaginalis. We found at first that the use of 4-methylumbellifferyl-substrate was responsible for a substrate affinity for the enzyme, about 1000-fold higher than those when using p-nitrophenyl-substrates (PNP). Whereas the optimum pH was 7.0 using PNP-substrate, it was at 4.5 using 4-methylumbelliferyl-substrate. Four different substrates were compared for their action on T. vaginalis NAHase and we have found that N-acetyl-beta-D-glucosaminide substrate was the most specific. DTT had no effect on enzyme activity suggesting that thiol group are not involved at the catalytic site. The use of previously described inhibitors showed a positive correlation between trichomonacidal activity and NAHase inhibition.

Screening of New Caledonian and Vanuatu medicinal plants for antiprotozoal activity

Sixty-seven extracts of 30 medicinal plants traditionally used in New Caledonia or Vanuatu by healers to treat inflammation, fever and in cicatrizing remedies were evaluated in vitro for their antiprotozoal activity against Leishmania donovani, Leishmania amazonensis and Trypanosoma cruzi. Among the selected plants, Pagiantha cerifera was the most active against both Leishmania species; four extracts were active against promastigotes of Leishmania donovani at EC(50) values inferior to 5 microg/ml. Garcinia pedicillata extract had an EC(50) value of 12.5 microg/ml against intracellular amastigotes of Leishmania amazonensis. Alone Amborella trichopoda reduced by more of 80% the trypomastigotes of Trypanosoma cruzi in the blood.

[Antileishmanial activity of five 2- or 3- quinolines by enyne group]

INTRODUCTION

Leishmaniasis is an emergent orphan disease because of its co-infection with HIV AIDS. We report herein the in vitro biological evalution of five news quinolines, 2- or 3-substituted by an enyne group against Leishmania donovani (MHOM/ET/L82/LV9).

PATIENTS AND METHODS

The quinolines has been synthesized by using a cross-coupling reaction between a chloroenyne and an organometallic coumpound in a presence of iron a "green" catalyst. Biological evalution is realized by a colorimetric method with the use of 3-(4,5-diméthylthiazol-2,5-diphényl)-tetrazolium bromide.

RESULTS

Determination of the inhibitory concentrations as well as the minimal inhibitory concentrations has shown that the substitution by an enyne group made it possible to have a more important antileishmanial activity. In addition, we have seen that the -2 or the -3 position of the e nyne group h ad no influence in the antileishmanial activity.

CONCLUSION

Thus, we have shown the real interest of these quinolines which could be favourably compared with pentamidine, which is currently the reference p roduct, and to consider the use of these quinolines in the treament of the leishmaniasis.

In vitro antileishmanial activity of acetogenins from Annonaceae

Twelve acetogenins from Annonaceae were evaluated in vitro for their antileishmanial activities in order to search for new lead-compounds having antileishmanial properties. The compounds were comparatively evaluated by the 50% inhibitory concentrations (IC50) determination on promastigote forms of wild-type and four drug-resistant lines of Leishmania donovani. In addition, after testing the toxicity on mouse peritoneal macrophages, the compounds were evaluated on amastigote infected macrophages and a therapeutic index was calculated. The IC50 of the acetogenins against promastigote forms of L. donovani was in a range 4.7-47.3 microM. The most active compound was Rolliniastatin 1 (IC50 at 4.7 microM). On the intramacrophage amastigote in vitro model, only seven compounds exhibited measurable antileishmanial activity with IC50 values in a range 2.5-29.7 microM. Rollinistatin 1 was the most interesting compound with IC50 of 2.5 microM and it appears as the most promising one on the basis of therapeutic index (18.08). Isoannonacin, which is active against intramacrophagic amastigotes (IC50 of 6.2 microM) with a therapeutic index of 2.05, exhibited a strong action on drug-resistant strains (IC50 from 5.1 to 9.8 microM). Acetogenins are a new chemical series with interesting in vitro antileishmanial activity and further studies will be focused on the understanding of this selectivity in regard to the membrane and mitochondrial action using specific probes.

Antiparasitic activities of medicinal plants used in Ivory Coast

During an ethnopharmacological survey of antiparasitic medicinal plants used in Ivory Coast, 17 plants were identified and collected. Polar, non-polar and alkaloidic extracts of various parts of these species were evaluated in vitro in an antiparasitic drug screening. Antimalarial, leishmanicidal, trypanocidal, antihelminthiasis and antiscabies activities were determined. Among the selected plants, Anogeissus leiocarpus and Terminalia glaucescens were strongly active against Plasmodium falciparum. Lawsonia inermis, selectively prescribed against trypanosomiasis shows interesting trypanocidal activities as did other 15 plants. Anthelmintic activities were found for 10 active species and 2 species (Uvaria afzelli and Monodora myristica) were actives against mites.

[Long circulating nanocapsules: interest in the treatment of severe malaria with halofantrine]

The aim of the work was to develop a new submicronic delivery system that can be used with poorly water soluble drugs for which sustained circulating concentrations are necessary. This system consists of oily core surrounded by a shell made of a copolymer of poly (D,L-lactid) and poly (ethylene glycol). Covalent coupling between the hydrophylic poly (ethylene glycol) and poly (D,L lactid) and high molecular weight of the poly (ethylene glycol) chains yield long circulating particles after intra-venous administration in mice. Halofantrine, a very effective drug administrated for the treatment of severe malaria caused by Plasmodium, for which no injectable preparation exists. Results showed that percentage of loading, yield of encapsulation and physical stability were more favourable with surface modified nanocapsules. Release of halofantrine was clearly related to partition between oil and external medium. Serum proteins in the medium, increased halofantrine release from nanocapsules and poly (ethylene glycol) grafted nanocapsules reduced this phenomenum. The pharmacokinetics of the free drug was modified to maintain it in blood circulation. It is important to note that high plasma concentrations of halofantrine were correlated with higher activity against parasites in mice infected with Plasmodium berghei.

[Results of fecal parasitologic examination performed on a population of wild chimpanzees (Pan troglodytes schweinfurthii) in Uganda ]

Two hundred and fifty two stool samples from 38 chimpanzees in a natural population in western Uganda were examined. Almost all individuals were infected but the number of parasites detected by the two techniques used was low. Significant seasonal differences were observed in prevalences.

Acaricidal activity of Uvaria versicolor and Uvaria Klaineana (Annonaceae)

Three Uvaria species, namely U. klaineana, U. mocoli and U. versicolor were tested in vitro against Dermatophagoides pteronyssinus, the European house dust mite. The most active extracts were the Uvaria versicolor stems crude methanol and hexane extracts with EC(50) values of 0.095 g/m(2 )and 0.12 g/m(2), respectively. The bioassay-guided fractionation of the hexane extract led to the isolation of benzyl benzoate (1). which exhibited an EC(50) value of 0.045 g/m(2). A new fl avanone, versuvanone (2). and the known oxoaporphine liriodenine (3). were also isolated from this species and showed EC(50) values > 1.5 g/m(2). A weak acaricidal activity (0.85 g/m(2)) was observed for the dichloromethane extract of Uvaria klaineana, due to the presence of benzyl benzoate. Uvaria mocoli was inactive. The structures of compounds were elucidated using 2D-NMR techniques.

[Antiparasitic effect of Senegalese Annonaceae used in traditional medicine]

Annonaceae is a large family of plants widely used in alimentation and traditional medicine. The interest of their study is raised up by the presence of biologically active substances among that the acetogenins which are specific to them. In Senegal, three species are widely used in traditional medicine for various indications and particularly in parasitic diseases: Annona senegalensis, Uvaria chamae and Xylopia aethiopica. The study of antiparasitical extracts from various organs showed an interesting activity of the fruits and leaves of Xylopia aethiopica on Leishmania donovani, the stem barks and roots of Uvaria chamae on Trypanosomia brucei and the roots of Annona senegalensis on the chloroquino-resistant strain of Plasmodium falciparum. Bioguided fractionation of the active extracts led to isolate Annonaceous acetogenins. Therefore, thirteen acetogenins, from the roots of Uvaria chamae and Annona senegalensis, were identified. The presence of acetogenins, substances with antiparasitical activity, could partly explain the biological proprieties of these various drugs.

The chitinase system from Trichomonas vaginalis as a potential target for antimicrobial therapy of urogenital trichomoniasis

Chitinolytic activities in Trichomonas vaginalis membrane extracts were assessed by assays of three enzyme systems: N-acetyl-beta-D-hexosaminidase (NAHase), chitobiosidase and chitotriosidase. N-acetyl-beta-D-hexosaminidase was the enzyme that showed the highest specific activity. After successive subcutaneous inoculations into mice and parasite recovery in culture, the enzyme activities increased significantly with the number of inoculations for up to eight passages. In addition, enzyme activities were maximum at the logarithmic phase of growth. Glycol chitin, a chitinase substrate, enhanced all chitinolytic activities by about 30% and a clear-cut correlation is shown between the capacity for erythrocyte lysis by parasites and NAHase expression. Chitobiosidase and chitotriosidase activities were both inhibited at 58% and 100%, respectively, by allosamidine, a chitinase inhibitor used at 3 microM, whereas NAHase activity was not affected. Seven putative NAHase inhibitors (compounds n, 1-7), ureido and thioureido derivatives of 2-amino-2-deoxy-D-glucose were evaluated and five of them had K(i) values in the range 30-70 microM. The most active compound (compound 6) was functionally competitive with respect to the substrate with a K(i) value of 30 microM. The IC(50) values of the most active compounds on T. vaginalis were in the range 62-85 microM. These results indicate that chitinases of T. vaginalis are involved in pathogenicity and they could be an interesting target for drugs since chitinase inhibitors also inhibit parasite growth.

In vitro antileishmanial activity of amphotericin B loaded in poly(epsilon-caprolactone) nanospheres

The activity of formulations for amphotericin B (AmB) associated with poly(epsilon-caprolactone) nanospheres and coated with variable amounts of a non ionic surfactant poloxamer 188, was evaluated against AmB-susceptible (WT) and AmB-resistant (AmB(r)) strains of Leishmania donovani amastigotes in thioglycolate-elicited peritoneal macrophages. AmB-nanospheres were more actives than free AmB only against amastigotes of wild strain. The activity was not influenced by the concentration of poloxamer 188 used to stabilize the nanospheres in spite of this surfactant was previously reported to synergy with AmB on the membrane of the resistant parasite. Similarly, this improvement was not mediated through macrophage activation. In fact, these nanoparticle formulations appeared to inhibit both NO and TNF-alpha production induced by the free drug. Therefore, we suggest that the association of AmB with nanospheres may improve the capability of the drug to interact with ergosterol. This hypothesis appears to be supported by the fact that nanospheres did not show any improvement of the AmB activity against the resistant strain (characterized by the absence of ergosterol).

Synthesis and trichomonacidal activity of perketals and hydroperoxides

Some perketals were synthesized by the Dussault procedure using simple bromides and 2-methoxyprop-2-yl hydroperoxide. Treatment with acetic acid gave the corresponding hydroperoxides. Both perketals and hydroperoxides were tested in vitro as trichomonacidal agents. Most of them exhibited very good activities. The most powerful compound was 2-methoxyprop-2-yl hexadec-l-yl peroxide which exhibited an IC50 value of 0.51 microM being 10 times more effective than the reference compound Metronidazole.

Design and antileishmanial activity of amphotericin B-loaded stable ionic amphiphile biovector formulations

A new delivery system, Ionic Amphiphilic Biovector (ABV), comprised of anionic lipids (dipalmitoyl phosphatidyl glycerol) included in a cationic cross-linked polysaccharide matrix was used as a reservoir for amphotericin B (AmB). Two ABV formulations exhibited an in vitro and in vivo efficacy similar to commercial AmBisome against Leishmania donovani-infected mice. The higher stability of these ABV formulations indicates their potential for further development and applications.

Synthesis and in vitro Trichomonacidal activities of some new dialkylperoxides and 1,2,4-trioxanes

Two series of three trioxanes and 18 disubstituted peroxides were synthesised and evaluated for their in vitro trichomonacidal activity against Trichomonas vaginalis. The most active compound, 2-methylprop-2-yl 2-methoxyeth-1-yl peroxide exhibited an IC(50) value of 1.0+/-0.2 microM whereas other dialkyl peroxides had various IC(50) values which could not be correlated to their molecule structure. The best compound was about five times more active than metronidazole. The amount of generated oxygen or free radicals cannot explain completely the activity suggesting another way of action for these compounds on T. vaginalis.

In vitro reversion of amphotericin B resistance in Leishmania donovani by poloxamer 188

A micellar formulation of amphotericin B (AmB) solubilized with poloxamer 188 was evaluated against an AmB Leishmania donovani-resistant line. A concave isobologram showed a synergistic effect of this association against promastigotes. This result was confirmed with amastigotes since the 50% effective concentration of the new formulation was 100 times less than that of the control AmB formulation.

In vivo antileishmanial action of Ir-(COD)-pentamidine tetraphenylborate on Leishmania donovani and Leishmania major mouse models

Ir-(COD)-pentamidine tetraphenylborate which has previously been studied on promastigote forms of Leishmania, was investigated for its antileishmanial properties compared with pentamidine used as reference compound. In vitro, the iridium complex had the same IC50 value on intracellular forms of Leishmania as pentamidine (15 microM). In vivo, the compound could not be injected intravenously due to the DMSO excipient so that the treatments were performed intraperitoneally or subcutaneously. On the L. donovani LV9/Balb/C mouse model, the iridium complex was not toxic after intraperitoneal treatment at 232 mg/kg/day x 5 or 147 mumoles/kg/day x 5, whereas all the mice died within five days when treated at the same dose with pentamidine isethionate. However, only 23% of parasite suppression was observed with the iridium complex. On a L. major MON 74/Balb/C mouse model, susceptible to intravenously administered pentamidine at 6.7 mumoles/kg/day x 5 (54% of parasite suppression), the iridium complex exhibited 32% of parasite suppression after a treatment at 76 mumoles/kg/day x 5 administered subcutaneously. This slight activity is of interest since pentamidine isethionate is not active under these conditions. Transmission electron microscopy of amastigotes from infected and treated mice show aggregation of ribosomal material, distension of the nuclear membrane and kDNA depolymerization. The mechanism of action therefore involves several targets: membranes, ribosomes and kDNA. According to our results, the Iridium complex is a suitable candidate to be encapsulated in drug carriers such as liposomes or nanoparticles.

Squamocin and benzyl benzoate, acaricidal components of Uvaria pauci-ovulata bark extracts

Annonaceae have been commonly described in traditional medicine as remedies against head lice and for their insecticidal properties. Acaricidal effects of Uvaria pauci-ovulata bark extracts were investigated on Dermatophagoides pteronyssinus, the European house dust mite, and compared with those of benzyl benzoate used as standard acaricidal compound. A dichloromethane extract was the most effective with an EC50 = 0.028 g/m2 after a 24 h period as compared with benzyl benzoate (EC50 = 0.06 g/m2). Bioassay-guided fractionation of this extract led to the isolation of benzyl benzoate and squamocin; this latter compound also had acaricidal properties (EC50 = 0.6 g/m2). Moreover, squamocin was shown to potentiate the activity of benzyl benzoate using the fractional effective concentration (FEC) method.

Marked elevation of serum N-acetyl-beta-D-hexosaminidase activity in rheumatoid rheumatoid arthritis

OBJECTIVE

To study N-acetyl-beta-D-hexosaminidase (NAHase) activity in the sera of rheumatoid arthritis (RA) patients and to determine its source.

METHODS

NAHase activity in the serum and synovial fluid of RA patients was measured with p-nitrophenyl beta-N-acetylglucosaminide as substrate. The p-nitrophenol released was measured spectrophotometrically in an ELISA reader. Rabbit articular chondrocytes in primary culture were stimulated with interleukin-1 beta (IL-1 beta).

RESULTS

Serum NAHase activity was higher in 35% of the RA patients than in healthy patients. The median activity was about twice that of the serum of healthy volunteers. RA patients with high serum NAHase activity also had more joint destruction (85%) than those with normal NAHase activity (57%, p < 0.05), but their inflammatory status was similar. The source of NAHase in RA was investigated by assaying it in RA synovial fluids (SF) and measuring its release from articular chondrocytes in primary culture. NAHase activity was detected in all 23 RA SF, at a median concentration that was 2 times that of the serum. NAHase activity in the medium of articular chondrocytes was stimulated by IL-1 beta (p < 0.005 compared to unstimulated cells), suggesting that cartilage is a source of serum and SF NAHase activity.

CONCLUSION

The serum concentration of the matrix hydrolase, NAHase, is higher in destructive RA than in inflammatory RA.

Antiprotozoal activity of aporphine alkaloids isolated from Unonopsis buchtienii (Annonaceae)

On a preliminary screening, substantial leishmanicidal activity was observed for the petroleum ether and alkaloidal extracts of the stem bark of Unonopsis buchtienii, the alkaloids and sterols isolated from these were studied. Of the alkaloids, liriodenine exhibited the highest activity against Leishmania major and L donovani (IC100 = 3.12 micrograms/mL). On the other hand, O-methylmoschatoline and the petroleum ether extract without alkaloids showed an interesting in vitro activity against Trypanosoma brucei with an IC100 of 6.25 micrograms/mL. The highest cytotoxic activities were found with the petroleum ether extracts without alkaloids and with all alkaloids isolated (IC50 < 9 micrograms/mL for Vero cell line).

A new photometric assay with bromocresol purple for testing in vitro antitrichomonal activity in aerobic environment

A new colorimetric assay relying on the acidic metabolism of Trichomonas vaginalis was developed for in vitro screening of various compounds against axenically grown trichomonads. Parasites from continuous culture were exposed to series of drug dilutions in a microtiter plate. After an incubation period of 48 h at 37 degrees C, the pH indicator of the medium had changed its colour in non-inhibited cultures due to the production of lactate and acetate. Inhibited cultures showed no colour changes. The use of bromocresol purple, a pH indicator, was suitable for several reasons: it is not toxic at the concentration used in the assay; the absorbance of bromocresol purple at 405 nm showed a linear correlation with both the pH of the medium and the viability of the trichomonads observed microscopically; plates could easily be read by eye or using an enzyme-linked immunosorbant assay (ELISA) reader. By comparison of the decreases in absorbance in test cultures with those in control cultures, IC50 values could be determined. Thus, IC50 of metronidazole was calculated at 25.5 +/- 2.3 mumol/l (n = 5) with the bromocresol purple assay and about 25 mumol/l after microscope observation. Minimal lethal concentrations (MLCs) could be read by eye. This test is now routinely used for anti-trichomonas evaluation of various chemical compounds and natural products.

Synthesis and biological evaluation of ureido and thioureido derivatives of 2-amino-2-deoxy-D-glucose and related aminoalcohols as N-acetyl-beta-D-hexosaminidase inhibitors

Ureido and thioureido derivatives of 2-acetamido-2-deoxy-beta-D-glucose, 1-amino-1-deoxy-D-glucitol and 2-(2-aminoethoxy)ethanol were prepared as N-acetyl-beta-D-hexosaminidase (NAHase) inhibitors and were evaluated on Trichomonas vaginalis NAHase. Although none showed complete inhibition of the enzyme at 100 microM, 1-amino-1-deoxy-D-glucitol derivatives acted as competitive inhibitors of the NAHase of T. vaginalis.