Assessing the reaction to and efficacy of the Screener drug discovery and development board game as a pedagogical tool in postgraduate courses

Screener, a board game supplemented with online resources, was introduced and distributed by the Brazilian Society of Pharmacology and Experimental Therapeutics to postgraduate programs as an instructional tool for the process of drug discovery and development (DDD). In this study, we provided a comprehensive analysis of five critical aspects for evaluating the quality of educational games, namely: 1) description of the intervention; 2) underlying pedagogical theory; 3) identification of local educational gaps; 4) impact on diverse stakeholders; and 5) elucidation of iterative quality enhancement processes. We also present qualitative and quantitative assessments of the effectiveness of this game in 11 postgraduate courses. We employed the MEEGA+ online survey, comprising thirty-three close-ended unipolar items with 5-point Likert-type response scales, to assess student perceptions of the quality and utility of Screener. Based on 115 responses, the results indicated a highly positive outlook among students. In addition, we performed a preliminary evaluation of learning outcomes in two courses involving 28 students. Pre- and post-quizzes were applied, each consisting of 20 True/False questions directly aligned with the game's content. The analysis revealed significant improvement in students' performance following engagement with the game, with scores rising from 8.4 to 13.3 (P<0.0001, paired t-test) and 9.7 to 12.7 (P<0.0001, paired t-test). These findings underscore the utility of Screener as an enjoyable and effective tool for facilitating a positive learning experience in the DDD process. Notably, the game can also reduce the educational disparities across different regions of our continental country.

Meta-Analysis of Human Cancer Single-Cell RNA-Seq Datasets Using the IMMUcan Database

The development of single-cell RNA sequencing (scRNA-seq) technologies has greatly contributed to deciphering the tumor microenvironment (TME). An enormous amount of independent scRNA-seq studies have been published representing a valuable resource that provides opportunities for meta-analysis studies. However, the massive amount of biological information, the marked heterogeneity and variability between studies, and the technical challenges in processing heterogeneous datasets create major bottlenecks for the full exploitation of scRNA-seq data. We have developed IMMUcan scDB (https://immucanscdb.vital-it.ch), a fully integrated scRNA-seq database exclusively dedicated to human cancer and accessible to nonspecialists. IMMUcan scDB encompasses 144 datasets on 56 different cancer types, annotated in 50 fields containing precise clinical, technological, and biological information. A data processing pipeline was developed and organized in four steps: (i) data collection; (ii) data processing (quality control and sample integration); (iii) supervised cell annotation with a cell ontology classifier of the TME; and (iv) interface to analyze TME in a cancer type-specific or global manner. This framework was used to explore datasets across tumor locations in a gene-centric (CXCL13) and cell-centric (B cells) manner as well as to conduct meta-analysis studies such as ranking immune cell types and genes correlated to malignant transformation. This integrated, freely accessible, and user-friendly resource represents an unprecedented level of detailed annotation, offering vast possibilities for downstream exploitation of human cancer scRNA-seq data for discovery and validation studies.

SIGNIFICANCE

The IMMUcan scDB database is an accessible supportive tool to analyze and decipher tumor-associated single-cell RNA sequencing data, allowing researchers to maximally use this data to provide new insights into cancer biology.

Abstract 2105: PD-L1 high ICOSL low Secretory dendritic cells infiltrate human solid tumors

Background: Human conventional dendritic cells (cDC) are essential for the anti-tumor immune response. Their immunogenic and tolerogenic states in cancer remain controversial. Our objective was to define the range of DC activation states in vitro and to determine their relevance ex vivo in cancer.

Methods: First, in vitro, we activated healthy donor cDC with 16 different stimuli and measured cDC and T cells cytokine and chemokine secretion upon co-culture (n = 130 individual experiments) to define new maturation archetypes. Second, we established the relevance of these archetypes in cancer, ex vivo in human. We performed in depth analysis of cDC infiltrating head and neck cancer (HNSCC) by flow cytometry (n = 22 patients), transcriptomic analysis (n = 6 patients), and cDC-enriched single-cell transcriptomics (ScRNAseq) (n = 10503 cells from 2 patients). Then we performed a merged analysis of cDC from in house and public ScRNAseq datasets (n = 36 tumor samples from HNSCC, Lung, and Breast cancer, and, as comparator, n = 33 blood and juxtatumor samples, n = 19 healthy donor samples, and n = 23 samples from inflammatory diseases).

Results: In vitro, we identified two archetypes of cDC activation: (i) PD-L1highICOSLlow cDC that produce large amounts of inflammatory cytokines and chemokines, labeled Secretory cDC; (ii)PD-L1lowICOSLhigh cDC that induce a broad range of Th cytokines, labeled Helper cDC. This functional dichotomy of cDC was mutually exclusive and not receptor specific. In cancer, we identified Secretory cDC, and these cells aligned with mature LAMP3+cDC. Helper cDC were not found ex vivo. Secretory cDC simultaneously expressed stimulatory (CD40, TNFRSF9 (4-1BB)), inhibitory (CD274, CD200, IDO1), and mixed (PVR) checkpoints. Secretory cDC were associated with T cell inflammation in HNSCC, triple-negative breast cancer (TNBC), and melanoma (all p &lt; 1.10-15), with improved overall survival in HNSCC and TNBC (all p &lt; 0.01), and with response to checkpoint blockade in 2 melanoma cohorts (all p &lt; 0.01).

Conclusion: We identify and characterize Secretory cDC in several solid cancers. This novel phenotypic and functional dichotomy of human cDC activation states has broad implications for all types of immunotherapies and provides rational for drug combinations.

Citation Format: Caroline Hoffmann, Floriane Noël, Maximilien Grandclaudon, Lucile Massenet-Regad, Paula Michea, Philemon Sirven, Lilith Faucheux, Aurore Surun, Olivier Lantz, Mylene Bohec, Jian Ye, Weihua Guo, Juliette Rochefort, Jerzy Klijanienko, Sylvain Baulande, Charlotte Lecerf, Maud Kamal, Christophe Le Tourneau, Maude Guillot-Delost, Vassili Soumelis. PD-L1 high ICOSL low Secretory dendritic cells infiltrate human solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2105.

SCREENER, an educational game for teaching the Drug Discovery and Development process

Although the use of games as an educational strategy is an important current trend, there is practically no option available for training people on the Drug Discovery and Development (DDD) process. To fill this gap, we designed “SCREENER”, a science game that is intended to be educational, but also challenging and interesting enough to ensure player engagement. Our main target audience is students of postgraduate programs in pharmacology, medicinal chemistry, pharmacy, and medicine. This game could also be of interest to the pharmaceutical industry and regulatory and patent agencies for training new employees. We discuss the creation of SCREENER, a hybrid of board and card games, and present its components with some examples of cards and resources, as well as the dynamics of the game. SCREENER mimics the process of drug discovery and development from validating a target to registering the new drug with the regulatory agency, and can be played individually (self-learning) or with the help of a monitor who assists up to six players/teams. Briefly, 29 task cards categorized in four major areas (efficacy, safety, pharmacokinetics, and pharmaceutical development) must be purchased sequentially. Classic characteristics of games such as decision making and challenge have been incorporated. More in-depth information on the tasks and technical terms is available through QR codes. The vagaries of the DDD process are mimicked by the bonus/setback cards. The evaluation of our first test with students is presented and supports the usefulness of this new tool.

On the scalar π K form factor beyond the elastic region

Pion-kaon ( π K ) pairs occur frequently as final states in heavy-particle decays. A consistent treatment of π K scattering and production amplitudes over a wide energy range is therefore mandatory for multiple applications: in Standard Model tests; to describe crossed channels in the quest for exotic hadronic states; and for an improved spectroscopy of excited kaon resonances. In the elastic region, the phase shifts of π K scattering in a given partial wave are related to the phases of the respective π K form factors by Watson's theorem. Going beyond that, we here construct a representation of the scalar π K form factor that includes inelastic effects via resonance exchange, while fulfilling all constraints from π K scattering and maintaining the correct analytic structure. As a first application, we consider the decay τ → K S π ν τ , in particular, we study to which extent the S-waveK 0 ∗ ( 1430 ) and the P-waveK ∗ ( 1410 ) resonances can be differentiated and provide an improved estimate of the CP asymmetry produced by a tensor operator. Finally, we extract the pole parameters of theK 0 ∗ ( 1430 ) andK 0 ∗ ( 1950 ) resonances via Padé approximants,s K 0 ∗ ( 1430 ) = [ 1408 ( 48 ) - i 180 ( 48 ) ] MeV ands K 0 ∗ ( 1950 ) = [ 1863 ( 12 ) - i 136 ( 20 ) ] MeV , as well as the pole residues. A generalization of the method also allows us to formally define a branching fraction for τ → K 0 ∗ ( 1430 ) ν τ in terms of the corresponding residue, leading to the upper limit BR ( τ → K 0 ∗ ( 1430 ) ν τ ) < 1.6 × 10 - 4 .

Systems analysis of human T helper17 cell differentiation uncovers distinct time-regulated transcriptional modules

T helper (Th) 17 cells protect from infections and are pathogenic in autoimmunity. While human Th17 cell differentiation has been defined, the global and stepwise transcriptional changes accompanying this process remain uncharacterized. Herein, by performing transcriptome analysis of human Th17 cells, we uncovered three time-regulated modules: early, involving exclusively “signaling pathways” genes; late, characterized by response to infections; and persistent, involving effector immune functions. To assign them an inflammatory or regulatory potential, we compared Th17 cells differentiated in presence or absence of interleukin (IL)-1β, respectively. Most inflammatory genes belong to the persistent module, whereas regulatory genes are lately or persistently induced. Among inflammatory genes, we identified the effector molecules IL17A, IL17F, IL26, IL6, interferon (IFN)G, IFNK, LTA, IL1A, platelet-derived growth factor (PDGF) A and the transcriptional regulators homeodomain-only protein homeobox (HOPX) and sex-determining-region-Y-box (SOX)2, whose expression was independently validated. This study provides an integrative representation of the stepwise human Th17 differentiation program and offers new perspectives toward therapeutic targeting of Th17-related autoimmune diseases.

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Human Th17 cells are driven by early, late, and persistent transcriptional modules.

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Human Th17 cells express IL17A, IL17F, IL26, IL6, IFNG, IFNK, LTA, IL1A, and PDGFA.

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RORC regulates the IL17A, IL17F, IFNG, PDGFA, and IL1A expression in human Th17 cells.

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HOPX and SOX2 contribute to the expression of IFNG by human Th17 cells.

Discrete analysis of camelid variable domains: sequences, structures, and in-silico structure prediction

Antigen binding by antibodies requires precise orientation of the complementarity- determining region (CDR) loops in the variable domain to establish the correct contact surface. Members of the family Camelidae have a modified form of immunoglobulin gamma (IgG) with only heavy chains, called Heavy Chain only Antibodies (HCAb). Antigen binding in HCAbs is mediated by only three CDR loops from the single variable domain (V_HH) at the N-terminus of each heavy chain. This feature of the V_HH, along with their other important features, e.g., easy expression, small size, thermo-stability and hydrophilicity, made them promising candidates for therapeutics and diagnostics. Thus, to design better V_HH domains, it is important to thoroughly understand their sequence and structure characteristics and relationship. In this study, sequence characteristics of V_HH domains have been analysed in depth, along with their structural features using innovative approaches, namely a structural alphabet. An elaborate summary of various studies proposing structural models of V_HH domains showed diversity in the algorithms used. Finally, a case study to elucidate the differences in structural models from single and multiple templates is presented. In this case study, along with the above-mentioned aspects of V_HH, an exciting view of various factors in structure prediction of V_HH, like template framework selection, is also discussed.

Biology and prognostic impact of clonal plasmacytoid dendritic cells in chronic myelomonocytic leukemia

Islands of CD123^high cells have been commonly described in the bone marrow of patients with chronic myelomonocytic leukemia (CMML). Using a multiparameter flow cytometry assay, we detected an excess of CD123⁺ mononucleated cells that are lineage-negative, CD45⁺, CD11c^-, CD33^-, HLA-DR⁺, BDCA-2⁺, BDCA-4⁺ in the bone marrow of 32/159 (20%) patients. Conventional and electron microscopy, flow cytometry detection of cell surface markers, gene expression analyses, and the ability to synthesize interferon alpha in response to Toll-like receptor agonists identified these cells as bona fide plasmacytoid dendritic cells (pDCs). Whole-exome sequencing of sorted monocytes and pDCs identified somatic mutations in genes of the oncogenic RAS pathway in the two cell types of every patient. CD34⁺ cells could generate high amount of pDCs in the absence of FMS-like tyrosine kinase 3-ligand (FLT3L). Finally, an excess of pDCs correlates with regulatory T cell accumulation and an increased risk of acute leukemia transformation. These results demonstrate the FLT3L-independent accumulation of clonal pDCs in the bone marrow of CMML patients with mutations affecting the RAS pathway, which is associated with a higher risk of disease progression.

ADME studies and preliminary safety pharmacology of LDT5, a lead compound for the treatment of benign prostatic hyperplasia

This study aimed to estimate the absorption, distribution, metabolism and excretion (ADME) properties and safety of LDT5, a lead compound for oral treatment of benign prostatic hyperplasia that has previously been characterized as a multi-target antagonist of α_1A-, α_1D-adrenoceptors and 5-HT_1A receptors. The preclinical characterization of this compound comprised the evaluation of its in vitro properties, including plasma, microsomal and hepatocytes stability, cytochrome P450 metabolism and inhibition, plasma protein binding, and permeability using MDCK-MDR1 cells. De-risking and preliminary safety pharmacology assays were performed through screening of 44 off-target receptors and in vivo tests in mice (rota-rod and single dose toxicity). LDT5 is stable in rat and human plasma, human liver microsomes and hepatocytes, but unstable in rat liver microsomes and hepatocytes (half-life of 11 min). LDT5 is highly permeable across the MDCK-MDR1 monolayer (P_app ∼32×10^-6 cm/s), indicating good intestinal absorption and putative brain penetration. LDT5 is not extensively protein-bound and is a substrate of human CYP2D6 and CYP2C19 but not of CYP3A4 (half-life >60 min), and did not significantly influence the activities of any of the human cytochrome P450 isoforms screened. LDT5 was considered safe albeit new studies are necessary to rule out putative central adverse effects through D₂, 5-HT_1A and 5-HT_2B receptors, after chronic use. This work highlights the drug-likeness properties of LDT5 and supports its further preclinical development.

[Fortuitous discovery of an adrenal mass following spontaneous retroperitoneal hemorrhage]

We report a case of spontaneous retroperitoneal haemorrhage by bleeding of an adrenal adenoma. Retroperitoneal haemorrhages are rarely encountered in practice, but must be rapidly diagnosed due to the life threatening risk. The etiologies, clinical assessment, management and differential diagnosis of spontaneous retroperitoneal haemorrhages are discussed.

Global analysis of VHHs framework regions with a structural alphabet

The VHHs are antigen-binding region/domain of camelid heavy chain antibodies (HCAb). They have many interesting biotechnological and biomedical properties due to their small size, high solubility and stability, and high affinity and specificity for their antigens. HCAb and classical IgGs are evolutionary related and share a common fold. VHHs are composed of regions considered as constant, called the frameworks (FRs) connected by Complementarity Determining Regions (CDRs), a highly variable region that provide interaction with the epitope. Actually, no systematic structural analyses had been performed on VHH structures despite a significant number of structures. This work is the first study to analyse the structural diversity of FRs of VHHs. Using a structural alphabet that allows approximating the local conformation, we show that each of the four FRs do not have a unique structure but exhibit many structural variant patterns. Moreover, no direct simple link between the local conformational change and amino acid composition can be detected. These results indicate that long-range interactions affect the local conformation of FRs and impact the building of structural models.

Non-competitive inhibitor of nucleoside hydrolase from Leishmania donovani identified by fragment-based drug discovery

New non-competitive inhibitor of nucleoside hidrolase fromL. donovaniidentified by fragment-based drug discovery using STD NMR and molecular docking.

Protein flexibility in the light of structural alphabets

Protein structures are valuable tools to understand protein function. Nonetheless, proteins are often considered as rigid macromolecules while their structures exhibit specific flexibility, which is essential to complete their functions. Analyses of protein structures and dynamics are often performed with a simplified three-state description, i.e., the classical secondary structures. More precise and complete description of protein backbone conformation can be obtained using libraries of small protein fragments that are able to approximate every part of protein structures. These libraries, called structural alphabets (SAs), have been widely used in structure analysis field, from definition of ligand binding sites to superimposition of protein structures. SAs are also well suited to analyze the dynamics of protein structures. Here, we review innovative approaches that investigate protein flexibility based on SAs description. Coupled to various sources of experimental data (e.g., B-factor) and computational methodology (e.g., Molecular Dynamic simulation), SAs turn out to be powerful tools to analyze protein dynamics, e.g., to examine allosteric mechanisms in large set of structures in complexes, to identify order/disorder transition. SAs were also shown to be quite efficient to predict protein flexibility from amino-acid sequence. Finally, in this review, we exemplify the interest of SAs for studying flexibility with different cases of proteins implicated in pathologies and diseases.

RNA/DNA co-analysis from human menstrual blood and vaginal secretion stains: results of a fourth and fifth collaborative EDNAP exercise

The European DNA Profiling Group (EDNAP) organized a fourth and fifth collaborative exercise on RNA/DNA co-analysis for body fluid identification and STR profiling. The task was to identify dried menstrual blood and vaginal secretion stains using specific RNA biomarkers, and additionally test 3 housekeeping genes for their suitability as reference genes. Six menstrual blood and six vaginal secretion stains, two dilution series (1/4-1/64 pieces of a menstrual blood/vaginal swab) and, optionally, bona fide or mock casework samples of human or non-human origin were analyzed by 24 participating laboratories, using RNA extraction or RNA/DNA co-extraction methods. Two novel menstrual blood mRNA multiplexes were used: MMP triplex (MMP7, MMP10, MMP11) and MB triplex (MSX1, LEFTY2, SFRP4) in conjunction with a housekeeping gene triplex (B2M, UBC, UCE). Two novel mRNA multiplexes and a HBD1 singleplex were used for the identification of vaginal secretion: Vag triplex (MYOZ1, CYP2B7P1 and MUC4) and a Lactobacillus-specific Lacto triplex (Ljen, Lcris, Lgas). The laboratories used different chemistries and instrumentation and all were able to successfully isolate and detect mRNA in dried stains. The simultaneous extraction of RNA and DNA allowed for positive identification of the tissue/fluid source of origin by mRNA profiling as well as a simultaneous identification of the body fluid donor by STR profiling, also from old and compromised casework samples. The results of this and the previous collaborative RNA exercises support RNA profiling as a reliable body fluid identification method that can easily be combined with current STR typing technology.

[Fungi, pets and their owners]

Some parasitic or pathogen fungi for pet skin are possibly transmitted to humans in whom they are responsible for superficial mycozoonoses. Cats, dogs and some small rodents are commonly involved. The lesions correspond to glabrous skin dermatophytoses and to microsporic tinea of the scalp. These disorders represent the vast majority of the prevalent mycozoonoses in Wallonia. Microsporum canis and Trichophyton mentagrophytes are the two fungi that are commonly involved.

Incidence of class A extended-spectrum -lactamases in Champagne-Ardenne (France): a 1 year prospective study

OBJECTIVES

To assess the frequency and diversity of extended spectrum beta-lactamases (ESBLs) in the Champagne-Ardenne region France, and to identify genetic elements associated with the bla(CTX-M) genes.

METHODS

During 2004, all the non-duplicate isolates of Pseudomonas aeruginosa and Acinetobacter baumannii resistant to ceftazidime and of Enterobacteriaceae intermediate or resistant to ceftazidime and/or cefotaxime, screening samples excluded, were collected in 10 public hospitals and 3 private clinics. bla genes were sequenced and bla(CTX-M) environment characterized by PCR mapping.

RESULTS

In Enterobacteriaceae (138/21 861; 0.6%), ESBLs were predominantly TEM-24 (n = 52; 37.7%) and CTX-M-15 (n = 37; 26.8%). Three new enzymes were identified, CTX-M-61 (CTX-M-1 group), TEM- and SHV-type. A. baumannii (n = 5) produced VEB-1 and P. aeruginosa (n = 2) SHV-2a. ISEcp1 was detected in 22/27 strains, disrupted in 7 of them. The IS903-like element was downstream of bla(CTX-M-14) and bla(CTX-M-16). ISCR1 was found upstream of bla(CTX-M-2) and bla(CTX-M-9), and ISCR1 and bla(CTX-M-2) were located on a sul1-type class 1 integron. In comparison with 2001-02, ESBL distribution among Enterobacteriaceae showed an increase in CTX-M-type (44.9% vs 3.7% P < 10(-7)) due to Escherichia coli CTX-M-15 and to the almost total disappearance of TEM-3 (0.9% vs 51.2%). E. coli was the most frequent species (50.0% vs 5.1% in 1998) despite a similar prevalence to that in 1998 (0.5% vs 0.2%).

CONCLUSIONS

A careful detection of bla(CTX-M)-type spread to other species would help to anticipate clonal endemics such as those observed in Enterobacter aerogenes TEM-24.

Schistosoma mansoni infection enhances host portal vein contraction: role of potassium channels and p38 MAP kinase

Murine Schistosoma mansoni infection is related to an increased contraction of portal vein in response to 5-hydroxytryptamine (5-HT). The present study addressed a putative alteration of ion channels and enzymes involved in vascular contraction. In control group, either inhibition of K+ channels sensitive to ATP (K(ATP)) or Ca2+ (BK(Ca)) increased 5-HT-induced contraction, but the same did not occur in infected mice. On the other hand, inhibition of p38 MAP kinase markedly decreased the vascular contraction to 5-HT in the infected mice with minor effects in the control group. Accordingly, we observed a higher density of phospho-p38 MAP kinase, that refers to the fully active state of the enzyme, in portal veins from infected mice as compared to control animals. These results suggest that the reduced function of K(ATP) and BK(Ca) channels along with an increased contribution of p38 MAP kinase contribute to the increased contraction of portal veins to 5-HT observed in murine schistosomiasis.

Characterization of two classes of benzodiazepine binding sites in Schistosoma mansoni

As we have recently shown that GABA should be considered a putative neurotransmitter inSchistosoma mansoni, the present work aimed to search for GABAAreceptors in adult worms using [3H]-flunitrazepam to label the allosteric benzodiazepine binding site which is classically present on GABAAreceptor complexes. We detected a large population (Bmax=8·25±1·1 pmol . mg protein−1) of high affinity (Kd=33·6±1·5 nm) binding sites for flunitrazepam. These sites harboured a singular pharmacological modulation that does not fit well with a mammalian central benzodiazepine receptor, mainly due to a very high affinity for Ro5-4864 and a very low affinity for clonazepam. We also detected a second population of benzodiazepine binding sites labelled with high affinity (IC50=85 nm) by [3H]-PK11195, a selective ligand of the mammalian peripheral benzodiazepine receptor. In conclusion, this work describes the pharmacological properties of a large population of central-like benzodiazepine receptors supporting their study as putative new targets for the development of anti-parasitic agents. We also describe, for the first time, the presence of peripheral benzodiazepine receptors in this parasite.

Noradrenaline-induced contraction of mice aorta is enhanced in schistosomiasis

Schistosomiasis, an intravascular parasitic disease caused by Schistosoma mansoni, is related to alterations of murine vascular reactivity in the mesenteric bed, characterized by an impairment of the l-arginine/NO pathway and an increased potency of 5-hydroxytryptamine. The current study was performed to test the hypothesis that a similar alteration of reactivity also occurs in the aorta and to identify the mechanism behind such an increase. We found that aorta from mice infected with male S. mansoni exhibited an enhanced contraction in response to noradrenaline and 100 mM KCl. The inhibition of nitric oxide synthase increased aortic maximal contraction in response to noradrenaline in both groups, but the effect was less pronounced in infected mice than in control mice. Endothelium-dependent relaxation induced by acetylcholine was also smaller in infected mice compared to control mice, while endothelial-independent relaxation induced by sodium nitroprusside and forskolin was similar in both groups. The inhibition of voltage-dependent L-type Ca(2+) channels reduced the maximal contraction in response to noradrenaline more effectively in infected than in control mice. Conversely the inhibition of K(ATP) channels had a smaller effect in the infected group. As a conclusion, our data indicate that schistosomiasis also alters murine vascular reactivity outside the mesenteric bed, due to a partial impairment of NO signaling, a reduced contribution of K(ATP) channels and an increased Ca(2+) influx through L-type Ca(2+) channels.

Role of calcium influx through voltage-operated calcium channels and of calcium mobilization in the physiology of Schistosoma mansoni muscle contractions

We tested the hypothesis that voltage-operated Ca2+ channels mediate an extracellular Ca2+ influx in muscle fibres from the human parasite Schistosoma mansoni and, along with Ca2+ mobilization from the sarcoplasmic reticulum, contribute to muscle contraction. Indeed, whole-cell voltage clamp revealed voltage-gated inward currents carried by divalent ions with a peak current elicited by steps to +20 mV (from a holding potential of -70 mV). Depolarization of the fibres by elevated extracellular K+ elicited contractions that were completely dependent on extracellular Ca2+ and inhibited by nicardipine (half inhibition at 4.1 microM). However these contractions were not very sensitive to other classical blockers of voltage-gated Ca2+ channels, indicating that the schistosome muscle channels have an atypical pharmacology when compared to their mammalian counterparts. Futhermore, the contraction induced by 5 mM caffeine was inhibited after depletion of the sarcoplasmic reticulum either with thapsigargin (10 microM) or ryanodine (10 microM). These data suggest that voltage-operated Ca2+ channels do contribute to S. mansoni contraction as does the mobilization of stored Ca2+, despite the small volume of sarcoplasmic reticulum in schistosome smooth muscles.

Characterization of a GABAergic neurotransmission in adult Schistosoma mansoni

The neuromuscular systems of parasitic helminths are targets that are particularly amenable for anthelmintics. In this study, we describe a GABAergic neurotransmission in adult Schistosoma mansoni, the trematode responsible for high levels of morbidity in people living in developing countries. GABA immunoreactivity (GABA-IR) was detected in nerve cells and fibres of the cerebral ganglia and longitudinal nerve cords and the nerve plexuses ramifying throughout the parenchyma of male adult worms. In addition, strong GABA-IR was also found associated with the oral and ventral suckers as well as in testes indicating a role for GABA in fixation to the host vascular wall and spermatogenesis. The capacity to synthesize GABA from glutamate was confirmed by measurement of a glutamate decarboxylase (GAD) activity. Supporting these data, a single band with an apparent molecular weight of about 67 kDa was detected using an antibody raised against mammalian GAD. In vivo studies revealed that picrotoxin, a non-competitive antagonist of the GABAA receptor, produced a modification of the motility and locomotory behaviour of adult worms, suggesting that GABAergic signalling pathway may play a physiological role in the motonervous system of S. mansoni and could be considered as a potential target for the development of new drugs.

Cellular mechanisms involved in the increased contraction of portal veins from Schistosoma mansoni-infected mice

We previously reported that portal veins from mice infected with male Schistosoma mansoni exhibited an increased reactivity to 5-hydroxytryptamine (5-HT). Here, we extended our observations to mice infected by both male and female worms and we further investigated another constrictor agent and the mechanism(s) responsible for the enhanced maximal contraction ( E(max)). Bisexual infection increased the E(max) of 5-HT (from 0.66+/-0.06 mN.s to 1.56+/-0.38 mN.s), in a similar way to the unisexual (male) infection. Infection with male worms increased portal vein reactivity to acetylcholine, as revealed by a higher E(max) (1.03+/-0.2 mN.s) in relation to non-infected control animals ( E(max)= 0.54+/-0.08 mN.s). Sarcoplasmic/endoplasmic reticulum Ca(2+)-ATPase (SERCA) inhibition with 100 nM thapsigargin reduced the E(max) of 5-HT by 35% in both tissues, discharging a deficiency of SERCA pump in infected animals. In contrast, the number of voltage-dependent Ca(2+) channels (L-type) was higher in portal veins from infected than non-infected control mice. Inhibition of Ca(2+)-activated chloride channels (Cl(Ca)) with 10 micro M niflumic acid reduced the E(max) of 5-HT in portal veins more from infected than non-infected animals (remaining tension = 60.9+/-2.2% and 70.4+/-2.3%, respectively). Histopathological analysis revealed an increased content of collagen and elastin in portal veins from male S. mansoni-infected mice, compatible with an increased intraluminal pressure. In conclusion, male S. mansoni altered portal vein physiology, increasing the E(max) of two vasoconstrictors, possibly by increasing membrane depolarisation through a more effective opening of Cl(Ca) channels, with calcium entering through L-type Ca(2+) channels.

Oligodendroglial expression of Edg-2 receptor: developmental analysis and pharmacological responses to lysophosphatidic acid

Edg-2 is a member of the G-protein-coupled seven-transmembrane receptor family recently identified in oligodendrocytes. Here we show that both in vitro and in vivo, Edg-2 transcripts are not detected during early stages of oligodendroglial development, but are expressed only in mature oligodendrocytes, shortly before the onset of myelination. Lysophosphatidic acid (LPA) has been reported to be a ligand of Edg-2 receptor in different cell types. However, in oligodendroglial cultures, LPA had no effect on survival, maturation, or cytoskeleton organization. In myelinating oligodendrocyte-neuron cocultures, LPA did not influence myelinogenesis. In addition, LPA failed to induce Ca2+ mobilization and had no effect on forskolin-induced cAMP accumulation. Phosphorylation of the ERK1/ERK2 MAP kinases was the only response elicited by LPA in oligodendrocytes. Therefore, in contrast to other cell types, in which LPA exerts pleiotropic effects, Edg-2-positive postmitotic oligodendrocytes display a restricted responsiveness to LPA.

Control of calcium homeostasis in Schistosoma mansoni

Calcium signalling is fundamental for muscular contractility of Schistosoma mansoni. We have previously described the presence of transport ATPases (Na+,K+-ATPase and (Ca2+-Mg2+)-ATPase) and calcium channels (ryanodine receptors - RyR) involved in control of calcium homeostasis in this worm. Here we briefly review the main technics (ATPase activity, binding with specific radioligands, fluxes of 45Ca2+ and whole worm contractions) and results obtained in order to compare the distribution patterns of these proteins: thapsigargin-sensitive (Ca2+-Mg2+)-ATPase activity and RyR co-purified in P1 and P4 fractions mainly, which is compatible with a sarcoplasmic reticulum localization, while basal ATPase (along with Na+,K+-ATPase) and thapsigargin-resistant (Ca2+-Mg2+)-ATPase have a distinct distribution, indicative of their plasma membrane localization. Finally we attempt to integrate these contributions with data from other groups in order to propose the first synoptic model for control of calcium homeostasis in S. mansoni.

Cyclic GMP-dependent vasodilatory properties of LASSBio 294 in rat aorta

. The effects of LASSBio 294, a new 3,4-methylenedioxybenzoyl-2-thienylhydrazone, on vascular tonus were investigated in isolated rat aortic rings. 2. LASSBio 294 induced a concentration-dependent relaxation of intact rat aortic rings with an inhibitory concentration (IC(50)) of 74 microM (95% confidence limits: 59 - 92). The mechanical removal of the endothelium abolished this effect. 3. In aortic rings with intact endothelium the effect of 100 microM LASSBio 294 was not altered by the pharmacological inhibition of NOS and cyclo-oxygenase pathways with 500 microM L-NAME and 10 microM indomethacin, respectively. 4. LASSBio 294 (100 microM) was able to relax aortic rings pre-contracted with high extracellular K(+) (KCl 100 mM). 5. The relaxant effect of LASSBio 294 was fully reversed (and prevented) by the addition of 1 microM ODQ (1H-(1,2,4)oxadiazolo[4,3-a]quinoxaline-1-one), a selective inhibitor of soluble guanylate cyclase. 6. LASSBio 294 (100 microM) had no direct effect on PDE3 and PDE4 activities, however, it increased by 150% cyclic GMP content in aortic rings pre-treated with 100 microM L-NAME and 10 microM indomethacin, as did 1 microM zaprinast, a selective PDE5 inhibitor. 7. In conclusion, LASSBio 294 induced relaxation of isolated rat aorta probably by directly increasing cyclic GMP content, possibly as a consequence of PDE5 inhibition.

Comparative bioavailability of two oral L-thyroxine formulations after multiple dose administration in patients with hypothyroidism and its relation with therapeutic endpoints and dissolution profiles

The aim of the present study was to evaluate the bioequivalence and therapeutic equivalence of the two most commonly prescribed L-thyroxine (monsodium L-thyroxine hydrate, CAS 25416-65-3) formulations in Brazil in patients treated for hypothyroidism. Twenty-four patients received 100 micrograms L-thyroxine daily of either Puran T4 (test) or the Brazilian reference formulation (reference) during 42 days, in a two-period crossover design. Serum samples obtained over a 24-h interval were analyzed for their total T4 concentration by a chemiluminescent immunoassay. Content and uniformity of the tablets and dissolution studies were also assessed according to USP 24 monograph using an isocratic HPLC-UV system and a rotating-paddle method. The mean pharmacokinetic parameters for total T4, expressed as geometric means (CV), for the test and reference were, respectively: Cmax (microgram/dl) 9.8 (14.3%) and 10.8 (14.9%); AUC0-24 h (microgram/dl.h) 206.8 (13.9%) and 230.4 (14.9%). Median values (90% CI) for Tmax (h) were 3 (2-3) and 2 (2-4) for the test and reference, respectively. 90% CI for ratios of LogCmax and LogAUC0-24 h were 86.6-94.9 and 86.3-93.4, respectively. Although the test exhibited values of Cmax and AUC0-24 h around 10% lower than the reference, these formulations must be considered bioequivalent since the 90% CI for both Cmax and AUC0-24 h mean ratio were within the 80-125% interval as proposed by the US Food and Drug Administration and the Brazilian legislation. TSH dosages within the normal range further support therapeutic equivalence between the two formulations. Dissolution data were roughly in agreement with in vivo results since both formulations comply with the USP dissolution criteria although the test tablets had a slower dissolution rate than the reference tablets. As a conclusion, the two oral formulations of L-thyroxine are both bioequivalent and therapeutically equivalent although presenting a small difference in their extent of absorption. Noteworthy, the dissolution profiles of the tablets correlate well with their bioavailability in the present experimental conditions.

Synthesis and preliminary pharmacological evaluation of coumestans with different patterns of oxygenation

Five coumestans with different patterns of oxygenation in rings A and D were synthesized from resorcinol and aromatic aldehydes, and screened for their antimyotoxic activity. The most potent compound (2b, IC50 = 1 microM) was selected for study of its pharmacological profile.

Radioligand binding assays in the drug discovery process: potential pitfalls of high throughput screenings

Radioligand binding assays evaluating directly the ability of a drug to interact with a defined molecular target is part of the drug discovery process. The need for a high throughput rate in screening drugs is actually leading to simplified experimental schemes that increase the probability of false negative results. Special concern involves voltage-gated ion channel drug discovery where a great care is required in designing assays because of frequent multiplicity of (interacting) binding sites. To clearly illustrate this situation, three different assays used in the academic drug discovery program of the authors were selected because they are rich of intrinsic artifacts: (I) (20 mmol/l caffeine almost duplicated [3H]ryanodine binding (89% higher than control) to rat heart microsomes at 0.3 mumol/l free calcium but did not exert any effect when using a high (107 mumol/l) free calcium, as mostly used in ryanodine binding assays; (II) An agonist for the ionotropic glutamate receptor of the kainate type can distinctly affect [3H]kainate binding to chicken cerebellum membranes depending on its concentration: unlabelled kainic acid per se either stimulated about 30% (at 50-100 nmol/l), had no effect (at 200 nmol/l) or even progressively decreased (at 0.3-2 mumol/l) the binding of 5 nmol/l [3H]kainate, emphasizing the risk of using a single concentration for screening a drug; (III) in a classical [3H]flunitrazepam binding assay, the stimulatory effect of a GABA (gamma-aminobutyric acid) agonist was only observed when using extensively washed rat brain synaptosomes (10 mumol/l GABA increased flunitrazepam binding by 90%). On the other hand, the inhibitory effect of a GABA antagonist was only observed when using crude synaptosomes (10 mumol/l bicuculine reduced [3H]flunitrazepam binding by 40%). It can be concluded that carefully designed radioligand assays which can be performed in an academic laboratory are appropriate for screening a small number of drugs, especially if these are potential hits because of their rational design. Therefore, the low throughput rate could be partially balanced by a higher performance when compared to what is done in a robotic high throughput screening where simplification of assay conditions can lead to false negative results.

Two distinct regions of the yeast mitochondrial ADP/ATP carrier are photolabeled by a new ADP analogue: 2-azido-3'-O-naphthoyl-[beta-32P]ADP. Identification of the binding segments by mass spectrometry

A novel photoactivatable radioactive ADP derivative, namely, 2-azido-3'-O-naphthoyl-[beta-(32)P]ADP (2-azido-N-[(32)P]ADP), was synthesized with the aim at mapping the substrate binding site(s) of the yeast mitochondrial ADP/ATP carrier. It was used with mitochondria isolated from genetically modified strains of Saccharomyces cerevisiae, producing the native or the His-tagged Anc2p isoform of the carrier. In darkness, 2-azido-N-[(32)P]ADP was reversibly bound to the carrier in mitochondria, without being transported. Upon photoirradiation, only the ADP/ATP carrier was covalently radiolabeled among all mitochondrial proteins. Specificity of labeling was demonstrated since carboxyatractyloside (CATR), a potent inhibitor of ADP/ATP transport, totally prevented the incorporation of the photoprobe. To localize the radioactive region(s), the purified photolabeled carrier was submitted to CNBr or hydroxylamine cleavage. The resulting fragments were characterized and identified by SDS-PAGE, Western blotting, amino acid sequencing, and MALDI-MS and ESI-MS analyses. Two short photolabeled distinct segments, eight and nine residues long, were identified: S183-R191, located in the central part of the ADP/ATP carrier; and I311-K318, belonging to its C-terminal end. Plausible models of organization of the nucleotide binding site(s) of the carrier involving the two regions specifically labeled by 2-azido-N-[(32)P]ADP are proposed.

Down-regulation of Na(+)/K(+)-ATPase alpha(2) isoform in denervated rat vas deferens

In the rat vas deferens, an organ richly innervated by peripheral sympathetic neurons, we have demonstrated recently the expression of alpha(1) and alpha(2), but not alpha(3) isoforms of the alpha subunit of Na(+)/K(+)-ATPase (EC 3.6.1.37), a membrane-bound enzyme of vital function for living cells (Noël et al., Biochem Pharmacol 55: 1531-1535, 1998). In the present work, we characterized, qualitatively and quantitatively, Na(+)/K(+)-ATPase alpha isoforms in denervated rat vasa deferentia. [(3)H]Ouabain binding at concentrations defined for high-affinity isoforms (alpha(2) and/or alpha(3)) detected only one class of specific binding sites in control (C) and denervated (D) vas deferens. Although the dissociation constant was similar for both groups [K(d) = 138 +/- 14 nM (C) and 125 +/- 8 nM (D)], a marked decrease in density was observed after denervation [716 +/- 81 fmol.mg protein(-1) (C) and 445 +/- 34 fmol.mg protein(-1) (D), P < 0.05]. In addition, western blotting revealed that denervated vasa deferentia produce the alpha(1) and alpha(2) isoforms but not alpha(3), just as we reported for the controls previously (Noël et al., Biochem Pharmacol 55: 1531-1535, 1998). Densitometric analysis showed a decrease of the alpha(2) isoform by about 40% in denervated organs, in very good agreement with what was shown with the [(3)H]ouabain binding technique, but no significant change in alpha(1) isoform density. Truncated alpha(1) (alpha(1)T), an isoform suggested to exist in the guinea pig vas deferens, was not detected. Altogether, our results demonstrated that Na(+)/K(+)-ATPase alpha(2) is down-regulated after sympathetic denervation of the rat vas deferens.

Purification of histidine-tagged mitochondrial ADP/ATP carrier: influence of the conformational states of the C-terminal region

A functional recombinant mitochondrial ADP/ATP carrier from the yeast Saccharomyces cerevisiae that bears a six-histidine tag at the C-terminus, Anc2(His(6))p, has been engineered to allow its purification by immobilized metal-ion affinity chromatography (IMAC). The tagged carrier was expressed at a level similar to that of unmodified Anc2p as determined by immunodetection and titration of the specific atractyloside binding sites. Anc2(His(6))p, enriched by chromatography on hydroxyapatite of detergent extracts of mitochondria, was still contaminated by mitochondrial proteins and a large amount of ergosterol. It was highly purified after adsorption on Ni-NTA resin and elution by imidazole buffer, with a 90-95% overall yield. Anc2(His(6))p interacted differently with immobilized ions depending on whether it was unliganded or bound to carboxyatractyloside (CATR) or bongkrekic acid (BA), two specific inhibitors of the ADP/ATP transport, thus indicating that accessibility of the C-terminus is markedly influenced by the conformational state of the carrier. Fluorometric assays demonstrated that purified unliganded Anc2(His(6))p was in a functional state since it underwent CATR- and BA-sensitive and ADP (or ATP)-induced conformational changes. Large-scale purification of Anc2(His(6))p-CATR and Anc2(His(6))p-BA complexes by IMAC will be of major interest for structural analysis of the ADP/ATP carrier.

Selective destruction of nigrostriatal dopaminergic neurons does not alter [3H]-ryanodine binding in rat striatum

Dopamine nigrostriatal neurons are important for motor control and may contain a particularly dense population of ryanodine receptors involved in the control of dopamine release. To test this hypothesis, we used a classical model of unilateral selective lesion of these neurons in rats based on 6-hydroxydopamine (6-OHDA) injection into the substantia nigra. Binding of [3H]-GBR 12935, used as a presynaptic marker since it labels specifically the dopamine uptake complex, was dramatically decreased by 83-100% in striatum homogenates after 6-OHDA lesion. On the contrary, no reduction of [3H]-ryanodine binding was observed. The present data indicate that [3H]-ryanodine binding sites present in rat striatum are not preferentially localized in dopaminergic terminals.

Communication of risks: organization of a methylmercury campaign in the Cree communities of James Bay, Northern Quebec, Canada

In the James Bay region of Canada, with the advent of extensive hydroelectric development, methylmercury contamination of fish has become a serious problem, having a direct impact on the Cree way of living. In 1982, the Cree Board of Health and Social Services of James Bay implemented a methylmercury exposure surveillance program in all Cree communities. Since that time, it has developed several educational tools on methylmercury contamination, including posters, pamphlets, and a video. In 1993 and 1994, Cree leaders, Community Health Representatives, medical staff, and other selected band members were consulted to identify the needs of the population regarding information on mercury. All questions and comments were listed, and a summary was sent to those consulted to double check the type of information required by the population. This led to the preparation of a brochure on mercury in a question and answer format, as well as creation of posters. The brochure and the posters were published in French, English and Cree and distributed in each community. A radio message was broadcast in all communities, and individual and group meetings were also held. Cree involvement in the mercury information program has been essential to its success.

Portal veins of mice infected with Schistosoma mansoni exhibit an increased reactivity to 5-hydroxytryptamine

In chronic severe infection with Schistosoma mansoni, portal hypertension and related vascular alterations usually develop as a consequence of granulomatous response to eggs. In order to investigate a putative direct effect of worms on the reactivity of their host portal vein, mice infected only with male worms were used in the present study. An higher reactivity to 5-hydroxytryptamine (5-HT) characterized by an increase in the maximal contraction and sensitivity was observed in portal vein from infected mice compared to healthy mice. Blockade of NO-synthase with l-NAME induced a small increase in 5-HT potency in portal vein from non-infected mice without changing the amplitude of the contractions, whereas it did not alter the reactivity of veins from infected mice. The present results show that unisexual infection of mice with male S. mansoni increased the reactivity of the portal vein to 5-HT which seems to be partially related to an alteration in the nitric oxide release by endothelium.

Evidence for ryanodine receptors in Schistosoma mansoni

The present study investigated the presence of ryanodine receptors in the trematode Schistosoma mansoni. [3H]Ryanodine specific binding sites were found in the four subcellular fractions of S. mansoni; however, more binding sites were recovered in the heterogeneous fraction P1 and the microsomal fraction P4, as was thapsigargin-sensitive (Ca2+-Mg2+)ATPase activity, marking the sarco/endoplasmic reticulum calcium ATPase (SERCA) pumps. This binding had an equilibrium dissociation constant (Kd) in the nanomolar range, an apparent maximal number of receptors (Bmax) of about 80 fmol/mg of protein, and was modulated by ions (Ca2+, Mg2+) and some pharmacological tools such as caffeine. Ryanodine was able to accelerate the rate of 45Ca2+ release from actively loaded vesicles, and also to induce a transient contraction of the whole worm. We conclude that ryanodine-sensitive Ca2+ release channels are present in S. mansoni, with properties very similar to the ones present in higher animals.

Increased reactivity to 5-hydroxytryptamine of portal veins from mice infected with Schistosoma mansoni

In chronic severe infection with Schistosoma mansoni, portal hypertension accompanied by anatomical changes of the portal vasculature can develop as a consequence of granulomatous response to eggs. Mice infected unisexually with male worms were used in the present study in order to investigate a direct effect of worms on the reactivity of their host portal vein. A higher reactivity in the presence of 5-hydroxytryptamine (5-HT), but not in the presence of KCl 100 mM solution, was observed in portal vein from infected mice compared to healthy mice. It was characterized by an increase in the maximal contraction and sensitivity to 5-HT. Blockade of NO-synthase with N omega-nitro-L-arginine methyl ester (L-NAME) induced a small increase in 5-HT potency in the portal vein from non-infected mice, but did not change the amplitude of the contractions. In portal veins from infected mice, preincubation with L-NAME did not affect the reactivity to 5-HT. Histological analysis indicated endothelial damage, subendothelial fibrous plaques, and focal areas of inflammatory infiltrates in the adventitial layer. As a conclusion, these results show that unisexual infection of mice with male S. mansoni increased the reactivity of the portal vein to 5-HT which seems to be only partially related to an alteration in the endothelial production of nitric oxide.

Mercury levels in the Cree population of James Bay, Quebec, from 1988 to 1993/94

BACKGROUND

High levels of mercury in the Cree population of James Bay, Que., have been a cause of concern for several years. This study examines changes in mercury levels within the Cree population between 1988 and 1993/94 and identifies potential determinants of high mercury levels.

METHODS

Data on mercury levels among the Cree were obtained through a surveillance program undertaken by the Cree Board of Health and Social Services of James Bay. In 1988 and again in 1993/94 surveys were carried out in all 9 Cree communities of northern Quebec. Hair samples were obtained and analysed for mercury content. Analyses were carried out to determine the proportion of people who had mercury levels in excess of established norms. Changes in mercury levels between 1988 and 1993/94 and determinants of high levels were estimated by means of regression methods.

RESULTS

The proportion of the Cree population with mercury levels in excess of 15.0 mg/kg declined from 14.2% in 1988 to 2.7% in 1993/94. Wide variations in mercury levels were observed between communities: 0.6% and 8.3% of the Eastmain and Whapmagoostui communities respectively had mercury levels of 15.0 mg/kg or greater in 1993/94. Logistic regression analyses showed that significantly higher levels of mercury were independently associated with male sex, increasing age and trapper status. There was a correlation between the mercury level of the head of the household and that of the spouse.

INTERPRETATION

Mercury levels in the Cree of James Bay have decreased in the recent past. Nevertheless, this decrease in mercury levels may not be permanent and does not necessarily imply that the issue is definitively resolved.

Quantitative analysis of the high-affinity binding sites for [3H]ouabain in the rat vas deferens and their immunological identification as the alpha 2 isoform of Na+/K(+)-ATPase

Binding assays were performed with [3H]ouabain to investigate the presence of, and to characterize, a Na+/K(+)-ATPase isoform with high affinity for cardiac glycosides in the rat vas deferens. Nonlinear regression analysis of equilibrium experiments carried out with crude preparations in a Mg-Pi medium indicated the presence of high-affinity sites characterized with good precision (individual coefficients of variation = 11-35%) by their density (Bmax = 0.42 to 0.72 pmol/mg protein) and dissociation constant (Kd = 0.069 to 0.136 microM) values. The values of the dissociation rate constant (kappa-1) and the association rate constant (kappa+1) for these sites were 0.151 to 0.267 min-1 and 2.87 to 3.60 microM-1.min-1, respectively. A higher number of low-affinity sites (Kd around 15 microM), supposed to correspond to the alpha 1 isoform, was also identified, but their Kd and Bmax values were not quantified precisely in this crude preparation. Western blot assays indicated hybridization with specific anti-alpha 1 and anti-alpha 2 isoform antibodies but not with anti-alpha 3 isoform antibody. Taken together, the present results indicate the existence of a low proportion of the alpha 2 isoform of Na+/K(+)-ATPase in the rat vas deferens that can be quantified precisely by [3H]ouabain binding even in a crude membrane preparation that is suitable for studies under conditions of plasticity.

Praziquantel has no direct effect on (Na(+)+K+)-ATPases and (Ca2(+)-Mg2+)ATPases of Schistosoma mansoni

Therapeutic concentrations of praziquantel produce a rapid and intense contraction of the human flatworm Schistosoma mansoni. As an action on ATPases responsible for calcium homeostasis arises as a possible explanation for the molecular mechanism of this effect, we tested here the effect of praziquantel on different preparations from male adult worms that were previously characterized for their content in (Na(+)+K+)-ATPase and (Ca2(+)-Mg2+)ATPase activities from different origins. Concentrations as high as 100 microM praziquantel did not inhibit (Na(+)+K+)-ATPase from tegument and carcass nor (Ca2(+)-Mg2+)ATPase from heterogeneous (P1) and microsomal (P4) fractions. As 100 microM praziquantel was also without effect on calcium permeability of microsomal vesicles actively loaded with 45Ca2+, the present results discard three hypotheses recently raised for the mechanism of praziquantel-induced contraction of S. mansoni.

[Evaluating quality of life of depressed patients in ambulatory care treatment]

This study concerns 1257 depressed outpatients, whose quality of life was evaluated before the beginning of a fluvoxamin treatment and six weeks later. We used the "Subjective Quality of Life Profile", questionnaire which has been previously validated in somatic diseases. The validation performed with these depressed patients appears to be quite satisfactory. The results provide a good description of the patients before the treatment: they seem to be indifferent to most domains by their health which they describe as very unsatisfactory. Contrasting with these results, patients' expectations appear to be very important in most domains, and the greater these initial expectations the poorer the evolution of their quality of life. After six weeks the patients' improvement in their quality of life is quite obvious especially in the somatic area. Another interesting finding concerns the high initial level of patients' expectations as compared with patients having somatic diseases. The higher these expectations, the poorer the outcome. It thus appears that a very sensitive self-questionnaire dealing with patients' quality of life in depression is available.

Evidence for the presence of two (Ca(2+)-Mg2+) ATPases with different sensitivities to thapsigargin and cyclopiazonic acid in the human flatworm Schistosoma mansoni

The subcellular localization of the (Ca(2+)-Mg2+)ATPase activities present in heterogeneous (P1), nuclear (P2), mitochondrial (P3) and microsomal (P4) fractions obtained by differential centrifugation of Schistosoma mansoni homogenate was investigated. In the microsomal fraction (P4), the (Ca(2+)-Mg2+)ATPase activity was completely blocked by 3 microM thapsigargin, whereas in the more heterogeneous fraction (P1), about 20-30% of this activity was resistant to the drug. The same pattern of inhibition was observed using 20 microM cyclopiazonic acid. The distribution pattern of (Ca(2+)-Mg2+)ATPase activity among the four subcellular fractions (P1 > P4 > > P3 > P2) was completely different from that of [3H]-ouabain binding sites (P1 > or = P4 = P2 > or = P3). These results indicate that the (Ca(2+)-Mg2+)ATPase in S. mansoni is predominantly of the SERCA type (localized in the endoplasmic reticulum). However, there is another enzyme, present in lower proportion that could have a plasma membrane origin (PMCA type), because it is resistant to thapsigargin and cyclopiazonic acid and its inhibition by tamoxifen is antagonized by calmodulin.