Classification-based QSARs for predicting dietary biomagnification in fish.

The assessment of bioaccumulation is an important step to describe the environmental behaviour and the potential risk due to exposure to potentially hazardous chemicals. In the last two decades, several in silico tools have been made available to predict bioconcentration, which is commonly used to assess bioaccumulation in risk assessment frameworks all over the world. However, only a few QSAR studies address the prediction of the biomagnification factor (BMF), which describes the accumulation of chemicals into organisms due to exposure through the diet. No classification models are currently available to this end. In this work, we developed classification QSARs to predict classes based on dietary biomagnification, using three different classifiers (i.e. LDA, ANN and RF). We started from a recently published dataset that includes more than 300 curated dietary BMF values measured in fish. The new models have high-quality performances (accuracy in fitting: from 94 to 96%; accuracy in prediction from 84 to 86%). The good performances of the here proposed QSARs confirm the quality of the original input data and highlight the importance of data curation and data sharing to support the development of new in silico approaches to assist risk assessment and chemicals screening.

Transcriptome Analysis of Plasmodium falciparum Isolates From Benin Reveals Specific Gene Expression Associated With Cerebral Malaria.

Cerebral malaria (CM) is the severest form of Plasmodium falciparum infection. Children under 5 years old are those most vulnerable to CM, and they consequently have the highest risk of malaria-related death. Parasite-associated factors leading to CM are not yet fully elucidated. We therefore sought to characterize the gene expression profile associated with CM, using RNA sequencing data from 15 CM and 15 uncomplicated malaria isolates from Benin. Cerebral malaria parasites displayed reduced circulation times, possibly related to higher cytoadherence capacity. Consistent with the latter, we detected increased var genes abundance in CM isolates. Differential expression analyses showed that distinct transcriptome profiles are signatures of malaria severity. Genes involved in adhesion, excluding variant surface antigens, were dysregulated, supporting the idea of increased cytoadhesion capacity of CM parasites. Finally, we found dysregulated expression of genes in the entry into host pathway that may reflect greater erythrocyte invasion capacity of CM parasites.

Association between chemical pattern in breast milk and congenital cryptorchidism: modelling of complex human exposures.

During the past four decades, there has been an increase in the incidence rate of male reproductive disorders in some, but not all, Western countries. The observed increase in the prevalence of male reproductive disorders is suspected to be ascribable to environmental factors as the increase has been too rapid to be explained by genetics alone. To study the association between complex chemical exposures of humans and congenital cryptorchidism, the most common malformation of the male genitalia, we measured 121 environmental chemicals with suspected or known endocrine disrupting properties in 130 breast milk samples from Danish and Finnish mothers. Half the newborns were healthy controls, whereas the other half was boys with congenital cryptorchidism. The measured chemicals included polychlorinated biphenyls (PCBs), polybrominated diphenyl-ethers, dioxins (OCDD/PCDFs), phthalates, polybrominated biphenyls and organochlorine pesticides. Computational analysis of the data was performed using logistic regression and three multivariate machine learning classifiers. Furthermore, we performed systems biology analysis to explore the chemical influence on a molecular level. After correction for multiple testing, exposure to nine chemicals was significantly different between the cases and controls in the Danish cohort, but not in the Finnish cohort. The multivariate analysis indicated that Danish samples exhibited a stronger correlation between chemical exposure patterns in breast milk and cryptorchidism than Finnish samples. Moreover, PCBs were indicated as having a protective effect within the Danish cohort, which was supported by molecular data recovered through systems biology. Our results lend further support to the hypothesis that the mixture of environmental chemicals may contribute to observed adverse trends in male reproductive health.

The impact of network biology in pharmacology and toxicology.

With the need to investigate alternative approaches and emerging technologies in order to increase drug efficacy and reduce adverse drug effects, network biology offers a novel way of approaching drug discovery by considering the effect of a molecule and protein's function in a global physiological environment. By studying drug action across multiple scales of complexity, from molecular to cellular and tissue level, network-based computational methods have the potential to improve our understanding of the impact of chemicals in human health. In this review we present the available large-scale databases and tools that allow integration and analysis of such information for understanding the properties of small molecules in the context of cellular networks. With the recent advances in the omics area, global integrative approaches are necessary to cope with the massive amounts of data, and biomedical researchers are urged to implement new types of analyses that can lead to new therapeutic interventions with increased safety and efficacy compared with existing medications.

Country-specific chemical signatures of persistent environmental compounds in breast milk.

Recent reports have confirmed a worldwide increasing trend of testicular cancer incidence, and a conspicuously high prevalence of this disease and other male reproductive disorders, including cryptorchidism and hypospadias, in Denmark. In contrast, Finland, a similarly industrialized Nordic country, exhibits much lower incidences of these disorders. The reasons behind the observed trends are unexplained, but environmental endocrine disrupting chemicals (EDCs) that affect foetal testis development are probably involved. Levels of persistent chemicals in breast milk can be considered a proxy for exposure of the foetus to such agents. Therefore, we undertook a comprehensive ecological study of 121 EDCs, including the persistent compounds dioxins, polychlorinated biphenyls (PCBs), pesticides and flame retardants, and non-persistent phthalates, in 68 breast milk samples from Denmark and Finland to compare exposure of mothers to this environmental mixture of EDCs. Using sophisticated, bioinformatic tools in our analysis, we reveal, for the first time, distinct country-specific chemical signatures of EDCs with Danes having generally higher exposure than Finns to persistent bioaccumulative chemicals, whereas there was no country-specific pattern with regard to the non-persistent phthalates. Importantly, EDC levels, including some dioxins, PCBs and some pesticides (hexachlorobenzene and dieldrin) were significantly higher in Denmark than in Finland. As these classes of EDCs have been implicated in testicular cancer or in adversely affecting development of the foetal testis in humans and animals, our findings reinforce the view that environmental exposure to EDCs may explain some of the temporal and between-country differences in incidence of male reproductive disorders.

Improving on nature's defenses: optimization & high throughput screening of antimicrobial peptides.

Antimicrobial peptides (AMPs) are ubiquitous in nature where they play important roles in host defense and microbial control. Despite their natural origin, antimicrobial spectrum and potency, the lead peptide candidates that so far have entered pharmaceutical development have all been further optimized by rational or semi-rational approaches. In recent years, several high throughput screening (HTS) systems have been developed to specifically address optimization of AMPs. These include a range of computational in silico systems and cell-based in vivo systems. The in silico-based screening systems comprise several computational methods such as Quantitative Structure/Activity Relationships (QSAR) as well as simulation methods mimicking peptide/membrane interactions. The in vivo-based systems can be divided in cis-acting and trans-acting screening systems. The cis-acting pre-screens, where the AMP exerts its antimicrobial effect on the producing cell, allow screening of millions or even billions of lead candidates for their basic antimicrobial or membrane-perturbating activity. The trans-acting screens, where the AMP is secreted or actively liberated from the producing cell and interacts with cells different from the producing cell, allow for screening under more complex and application-relevant conditions. This review describes the application of HTS systems employed for AMPs and lists advantages as well as limitations of these systems.

Database mining applied to central nervous system (CNS) activity.

A data set of 389 compounds, active in the central nervous system (CNS) and divided into eight classes according to the receptor type, was extracted from the RBI database and analyzed by Self-Organizing Maps (SOM), also known as Kohonen Artificial Neural Networks. This method gives a 2D representation of the distribution of the compounds in the hyperspace derived from their molecular descriptors. As SOM belongs to the category of unsupervised techniques, it has to be combined with another method in order to generate classification models with predictive ability. The fuzzy clustering (FC) approach seems to be particularly suitable to delineate clusters in a rational way from SOM and to get an automatic objective map interpretation. Maps derived by SOM showed specific regions associated with a unique receptor type and zones in which two or more activity classes are nested. Then, the modeling ability of the proposed SOM/FC Hybrid System tools applied simultaneously to eight activity classes was validated after dividing the 389 compounds into a training set and a test set, including 259 and 130 molecules, respectively. The proper experimental activity class, among the eight possible ones, was predicted simultaneously and correctly for 81% of the test set compounds.

Cytogenetics and their prognostic value in childhood and adult acute lymphoblastic leukemia (ALL) excluding L3.

Cytogenetic analysis was made at diagnosis in 174 cases of ALL (101 children less than 20 years and 73 adults), excluding Burkitt's ALL (L3). In 11 children (11 per cent) insufficient material was obtained. In the remaining 90, 50 (56 per cent) had a normal karyotype, 20 (22 per cent) a hyperdiploid karyotype, five (6 per cent) a hypodiploid karyotype, 12 (13 per cent) had a translocation (including seven cases of t(1;19] and three had a pseudodiploid karyotype without translocation. Ninety-eight per cent of patients reached complete remission (CR). Median actuarial CR duration was not attained, was 50 months, 13 months, and 11 months respectively in patients with hyperdiploid, normal, hypodiploid karyotype and in patients with a translocation, the difference between subgroups being significant. In a Cox model, cytogenetics were the strongest factor predicting CR duration (p = 0.03) followed by leukocytes (p = 0.04), whereas the presence of 'bulky disease' had a borderline value (p = 0.077). Of note was that 9/17 (53 per cent) patients with a hypodiploid karyotype or a translocation had no 'risk factors' before cytogenetic analysis. In adults, cytogenetic analysis was unsuccessful in 15 (20 per cent) of patients. In the remaining 58 cases, 19 (33 per cent) had a normal karyotype, 15 (26 per cent) had a hyperdiploid, one (2 per cent) had a hypodiploid karyotype, 19 (33 per cent) had a translocation (including 12 t(9;22], and four (7 per cent) had a pseudodiploid without translocation. 73 per cent patients reached CR. Median actuarial DFS was 12.5 months. No significant differences in CR rate and CR duration were seen between cytogenetic groups, but median CR duration was slightly longer in patients with a normal karyotype (17 months) and shorter in patients with t(9;22) (8.5 months). Only 3/12 of the latter had major risk factors before cytogenetic analysis. Cytogenetic analysis is important in ALL, especially in patients with otherwise standard risk factors, as it may reveal unexpected translocations or hypodiploidy, which may require a therapeutic reinforcement.

Ifosfamide is an active drug in Wilms' tumor: a phase II study conducted by the French Society of Pediatric Oncology.

Twenty-one patients with advanced Wilms' tumor entered a phase II study with high-dose ifosfamide (3 g/m2 over two days every 15 days). Mesna and hyperhydration were associated with minimal bladder toxicity. After two courses, five partial responses and six complete responses were observed. Ten patients did not respond. The median duration of response was 2 months (range, 1 to 7). Therapy was delayed because of leukopenia for 1 or 2 weeks in only three cases. Fever and infection were not observed. Seven patients presented with hematuria, three of whom were among the 17 patients coadministered mesna, which did not interfere with subsequent therapy.

Acute monoblastic leukemia with osteosclerosis and extensive myelofibrosis.

A 4-month-old infant was admitted with a monoblastic infiltration of the skin associated with osteosclerosis. Both lesions spontaneously disappeared within a few months, but 2 years later, a monoblastic leukemia occurred that was associated with marked skin erythema and myelofibrosis. Skin and bone marrow specimens showed a monoblastic infiltration with numerous intermingled mast cells of normal appearance. Whether myelofibrosis was a feature of a systemic mastocytosis or of the leukemic process is discussed in this case.

Ultrasonographic findings in thymic lymphoma in children.

The sonographic manifestations of thymic involvement by T lymphoblastic non-Hodgkin's lymphoma/leukaemia in 6 children are presented. The criteria which may help in its differentiation from a normal thymus gland are reviewed. Hypoechoic and non-homogeneous large masses are the most typical presentation of thymic infiltration. Fixity of tumour and compression of surrounding structures are the most important associated signs with pleural and pericardial effusions. In children, ultrasonography of the mediastinum can play a role by establishing the nature of anterior masses.

[Treatment of febrile episodes in neutropenic children by ceftazidime combined with netilmicin. Results of a multicenter study apropos of 88 cases]. / Traitement des épisodes fébriles chez les enfants neutropéniques par la ceftazidime associée à la nétilmicine. Résultats d'une étude multicentrique à propos de 88 observations.

Infection is the most important cause of mortality in leucopenic patients. A broad spectrum antibiotic therapy is imperative in febrile and neutropenic patients. In a multicentric study we have used ceftazidime (100 mg/kg/d) and netilmicin (6 mg/kg/d) in 88 children (fever greater than or equal to 38.5 degrees C, neutropenia less than 500/mm3) treated for acute leukemias (59), non Hodgkin lymphomas (13) or solid tumors (16). Median age was 7 years (2 months-16 years). In patients who continued to remain febrile, vancomycin (40 mg/kg/d) was added after 48 hours. The effective treatment was continued until a neutrophil count greater than 1,000/mm3. The first combination (ceftazidime + netilmicin) was effective in 64 children (73%) and the second combination (ceftazidime + netilmicin + vancomycin) in 11 patients. Bacteria were isolated in 39 children: Escherichia coli: 9, Staphylococcus epidermidis: 9, Staphylococcus aureus: 8, Streptococcus: 6, Pseudomonas aeruginosa: 3, Streptococcus pneumoniae: 1, Haemophilus: 1, Klebsiella pneumoniae: 1, Proteus: 1, Serratia: 1, Flavobacterium: 1. In these 39 patients, 30 became apyretic with ceftazidime and netilmicin and 6 after vancomycin. All blood culture were negative after the first combination. The median duration of antibiotic therapy was 14 days (5-9 days: 28, 10-20 days: 43, greater than 20 days: 17). There were no death, no superinfection. Tolerance was good without kidney or liver or biological perturbation. We conclude that the combination ceftazidime and netilmicin is effective in neutropenic children.

[Graft versus host reaction following materno-fetal transfusion. Apropos of 1 case]. / Réaction du greffon contre l'hôte après transfusion materno-foetale. A propos d'une observation.

After GVHR by probable maternal-foetal in utero transfusion, a male infant carrying a serious combined immune deficit (DICS) has presented a second post transfusional GVHR. On the occasion of this observation, the authors recall the main signs which permit to evoke this rare diagnosis as early as possible, as well as some main preventive measures that can be applied in current practice.