Altérations cytologiques induites par la zéaralénone chez Bacillus thuringiensis (Berliner)

Zearalenone (F-2 toxin) an estrogenic mycotoxin secreted by some species ofFusarium exhibits an antibacterial activity which can be easily demonstrated in Gram-positive spore forming bacteria, especially inBacillus sp.Morphologically abnormal cells were produced byBacillus thuringiensis (Berliner) in response to zearalenone. The most significant ultrastructural alterations obtained with the mycotoxin at 2.5 or 5.0 g/ml, are: increase of number of mesosomes which are hypertrophied, decrease of ribosomes, formation of imperfect cell septa and unknown crystalloid inclusion.These effects which provoke induction of atypical long cells, resemble those obtained with one other mycotoxin which possesses as zearalenone an unsaturated lactone structure: aflatoxin B₁.     

Sexualisation de la gonade deViviparus viviparus L. (mollusque gastéropode prosobranche à sexes séparés)

Résumé La sexualisation de la gonade chezViviparus viviparus se manifeste d'abord au niveau morphologique: tandis que l'ovaire s'organise en un tubule très peu ramifié, à large lumière, le testicule compact bourgeonne de nombreuses excroissances. Dans l'ovaire les cellules non germinales, futures cellules folliculeuses, se mettent en place autour des cellules germinales et les processus de la préméiose débutent précocement. Au contraire plusieurs étapes se succèdent au cours de la morphogenèse de la gonade mâle: après une phase d'intense multiplication cellulaire, accompagnée de la ramification du testicule, la lumière se creuse par dégénérescence des cellules centrales. Contre la lame basale, les cellules non germinales évoluent en cellules nourricières tandis que se différencient les spermatogonies primaires. La différenciation des premiers gamètes mâles est tardive.     

Sur quelques propriétés physico-chimiques des protéines séparées des sérums par la méthode à l'acétone

Sans résuméCes diverses études conduisent toutes à cette conclusion que la séparation des protéines effectuée à basse température par la méthode dite à l'acétone de MM.Piettre etVila respecte l'intégrité des molécules protéiques.     

Syndromes paranéoplasiques : intérêt de la tomographie par émission de positons (TEP) au 18F-fluoro-déoxyglucose (FDG)

BackgroundWe evaluated the performance of ¹⁸F-fluorodeoxyglucose (¹⁸FDG) positon emission tomography (PET) in the diagnosis of underlying malignancy in cases of suspected paraneoplastic syndrome (PS).Methods¹⁸FDG-PET was performed in 31 patients, clinically suspected to have PS. The PS were 34, among which 12 neurological diseases, eight endocrine, seven rheumatological, one dermatological and six vascular. We compared computed tomography (CT), iodine-enhanced most of the time, and ¹⁸FDG-PET reports to clinicians definitive conclusion at the end of the work-up and a follow-up period of, at least, two months.ResultsWe obtained a histological diagnosis of cancer for ten patients, but could only identify the primary site of malignancy for nine of them. ¹⁸FDG-PET showed six primary sites among which three were not seen on CT. CT disclosed four primary sites, among which one was not seen on ¹⁸FDG-PET. In one case, ¹⁸FDG-PET disclosed regional lymph node metastases whereas these were not identified by CT. Eleven non-neoplasic causes were evidenced, among which ¹⁸FDG-PET played a major role in three cases. Ten causes were still undetermined at the end of the study.ConclusionWhole-body ¹⁸FDG-PET study plays an important role in the identification of underlying malignancy in clinically suspected paraneoplastic syndromes; either by identifying the primary tumor or by directing biopsy of metastases. Furthermore, it can identify non-neoplasic causes.     

Modélisation des flux cérébraux par une analogie électrique : validation par vélocimétrie IRM

The cine Phase-Contrast Magnetic Resonance (PCMR) sequence is the only noninvasive technique for the study of cerebrospinal fluid (CSF) oscillations. It can provide CSF and blood flow measurements throughout the cardiac cycle. To study cerebral hydro-hemodynamic, models have been developed; nevertheless the majority of these models did not take into account the CSF oscillations. The objective of this study was to establish reference values for cerebral hydro-hemodynamic and propose a new electrical model of the brain dynamics.Material and methodsCSF and blood flows were measured in 19 control subjects by PCMR imaging. Dynamic flow images were analyzed on dedicated software to reconstruct the flow curves during the cardiac cycle. An electrical analogue was realized. The inputs of the model were fed by PCMR arterial and venous flows to simulate CSF oscillations. The simulated CSF oscillations were compared to the measured CSF oscillations to validate the model.ResultsThe key parameters of the CSF and blood flow curves were obtained, e.g. total cerebral blood flow was 688 ± 115 mL/min, ventricular CSF oscillatory volume was 0.05 ± 0.02 mL/cardiac cycle, and the subarachnoid CSF oscillatory volume was 0.55 ± 0.15 mL/cardiac cycle. A close agreement was found between measured and simulated cerebral CSF oscillations.ConclusionThis study established the main values characterizing cerebral hydrodynamics in a control population. It provided a better understanding of the mechanisms of intracranial volumes regulation during the cardiac cycle. Our results are now used in clinical practice and the model proposed is effective to study cerebral hydro-hemodynamic.     

Tératogénie des anomalies axiales induites par un insecticide organophosphoré (le parathion) chez l'embryon d'oiseau

Résumé Chez les embryons de poulet et de caille, issus d'oeufs exposés au parathion au stade non incubé ou au cours des 48 premières heures, les anomalies axiales spécifiques de ce composé apparaissent entre 4 et 5 jours chez le Poulet et après 5 jours d'incubation chez la Caille. Les premières altérations accessibles aux examens morphologiques se traduisent par un tassement de certains myotomes ainsi que par des torsions de la chorde et du tube neural. Les anomalies se développent rapidement chez le Poulet alors que chez la Caille elles se mettent en place progressivement.Chez les deux espèces, les métamérisations primaire et secondaire (provertèbres) s'effectuent normalement. Alors que les premières phases des phénomènes de chondrification sont conformes à la normale, on assiste par la suite à la généralisation de ce processus qui conduit à l'effacement de la métamérie secondaire. Chez la Caille, des soudures vertébrales (ares neuraux et corps vertébraux) affectent des zones non touchées par les plissements.Des traitements au parathion, réalisés à différents stades de l'incubation (2e et 3e tiers de la vie embryonnaire) induisent chez le Poulet et la Caille, des déformations axiales tout à fait comparables, sur le plan morphologique, à celles engendrées par les traidements précoces. Toutefois, il y a lieu de souligner que les soudures vertébrales sont d'autant plus rares que le traitement est plus tardif.Chez l'embryon de Poulet de 16 jours, les scolioses cervicales sont en place 5 heures après l'injection du toxique. L'apparition rapide de cette malformation ainsi que les résultats des études tératogéniques réalisées après des traitements précoces, conduisent à penser que les troubles morphogénétiques ne sont pour l'essentiel qu'une conséquence d'une altération de la physiologie et/ou de la différenciation du tissu musculaire ce qui est en accord avec une hypothèse précédemment émise (Meiniel Lutz-Ostertag et Lutz, 1969).

---

Teratogenesis of axial abnormalities induced by an organic phosphorus insecticide (parathion) in the bird embryo

Summary Parathion, administered before incubation or at the beginning of development (48 h) induces specific axial deformities which occur between 4 and 5 days in the chick and after 5 days of incubation in the quail. Morphological studies indicate that the teratogenic effects are first represented by myotome compressions, notochordal and neural tube distortions.The abnormalities develop quickly in the chick embryo but take place gradually in the quail embryo.In the two species, somites and primitive vertebrae undergo a normal differentiation and the perinotochordal cells differentiate into chondroblast like in the normal way. But later, the chondrogenesis extends to the intervertebral clefts and gives rise to the formation of an unsegmented vertebral column. In the quail, vertebral fusions are encountered in regions where no torsion occurs.Cervical malformations can develop in quail and chick embryo, when parathion is injected at late stages (2nd and 3rd thirds of the embryonic life).The axial deformities are morphologically similar to those observed after early treatment. But, vertebral fusions are rarer the later the embryos are treated.In chick embryos of 16 days' incubation, the cervical scoliosis occurs 5 h after the treatment. The rapid occurrence of the malformation and the results obtained after early treatment support the hypothesis advanced earlier that the disturbed morphogenesis is caused — in great part — by an abnormal physiology and/or differentiation of the muscles (Meiniel, Lutz-Ostertag et Lutz, 1969).

     

Le diagnostic et le suivi thérapeutique des tumeurs cérébrales intra-parenchymateuses par l’imagerie par résonance magnétique multimodale

The multimodal magnetic resonance imaging (MMRI) has an important role in cancer care. This non-invasive and non-ionizing technique provides vital information for the diagnosis and answers to various questions of clinicians before, during and after treatment. The MMRI can specify the localization expanding process; it allows establishing the differential diagnosis of a brain tumor and a circumscribed lesion of another type, to approach the diagnosis of the tumor lesion nature as well as establishing the histological grade of glial tumor in view of lesion monitoring after treatment. The multimodal magnetic resonance imaging has a major contribution to the management progress of the brain tumors. Thus, this paper reviews the value of these MRI modalities in the diagnosis, management and therapy of brain tumors.     

Effets secondaires d’un stress par Régadénoson en scintigraphie myocardique chez les patients traités par Ticagrélor

IntroductionAs an anti-aggregant that has demonstrated its superiority in the management of acute coronary syndrome, Ticagrelor is an inhibitor of adenosine recapture by red blood cells. Regadenoson, an adenosine agonist, is a preferred cardiac pharmacological stress in patients with a history of spastic bronchopathy. A synergistic effect of both drugs is therefore theoretically expected if they are combined during myocardial scintigraphy. In 2015, European Association of Nuclear Medicine did not rule on the use of Regadenoson in patients previously treated with Ticagrelor. The objective of this work is to study the frequency of adverse events in these patients during Regadenoson stress.Materials and methodsWe retrospectively included patients who underwent a myocardial scintigraphy with pharmacological stress by Regadenoson between February 2016 and February 2019. We compared the frequency of expected side effects of Regadenoson in patients treated with Ticagrelor and not treated with Ticagrelor. The data were analysed using a logistic regression model including patient characteristics and side effects.ResultsSeventeen treated patients were included for 49 untreated patients. There was no significant difference in the frequency of each adverse event between treated and untreated patients. However, a higher number of side effects have been reported in treated patients than in untreated patients. No major adverse event was reported.ConclusionIn order to rule about the use of Regadenoson in patients treated with Ticagrelor, a larger study is needed to support the hypothesis of more noted minor side effects and which of them should be more encountered.     

Fragmentation radio-induite de l'ADN évaluée par immunomarquage anti poly(ADP-ribose) dans les CHO. Étalonnage par électrophorèse en champ pulsé

The poly (ADP-ribose) polymerase is an ubiquitous nuclear protein capable of binding specifically to DNA strand breaks. It synthesizes ADP-ribose polymers proportionally to DNA breaks. The actual method of reference to determine DNA double strand breaks is pulsed-field gel electrophoresis, but this requires many cells. It thus appeared of interest to use poly (ADP-ribos) ylation to follow and estimate γ-ray-induced DNA fragmentation at the level of isolated cells after γ-irradiation in chinese hamster ovary cells (CHO-K1). The results obtained by the immunolabelling technique of ADP-ribose polymers were compared to those obtained by pulsed-field gel electrophoresis. They show that poly (ADP-ribos)ylation reflects the occurrence of radiation-induced DNA strand breaks. A clear relationship exists between the amount of ADP-ribose polymers detected and DNA double strand breaks after γ-irradiation.     

Imagerie moléculaire du transporteur vésiculaire de l’acétylcholine (VACh) par le [123I]-5-iodobenzovézamicol dans la démence de type Alzheimer (DTA)

Alzheimer's disease (AD) is characterized by a premature decline of cholinergic neurons. The 5-IBVM is an analogue of the vesamicol that binds to the presynaptic vesicular acetylcholine transporter (VAChT). The exploration of this target should be useful to make an early diagnosis of AD. Our first aim was to propose a method of non invasive VAChT quantification according to 5-IBVM kinetic. 5-IBVM was injected to four AD patients (age = 77 ± 3.9 years and MMSE = 24.5 ± 1.02) were included in this methodological study. The single-photon emission computed tomography (SPECT) images were obtained at five, 20, 35 and 50 minutes, at then at three, five and 22 hours after intravenous injection of 5-IBVM (185MBq). The time activity curves were obtained after SPECT images coregistration on a MRI masque. Specific volume of interest (SPE = SPEcific) were manually drawn on striatum, pons, thalamus and para-hippocampic gyrus including hippocampus; reference volumes of interest (REF = REFerence) were drawn on frontal and occipital cerebral cortex. On the basis of uptake kinetic, two modelisation approaches were considered: transient equilibrium model for reversible ligand (binding potential (BP) = (SPE ? REF)/REF) and Patlak graphical analysis for irreversible tracers (slope given by K_i/DV_ref where K_i is the influx contant and DV_ref is the distribution volume of the reference region). We observed an inflection or a stady state of the activity curves in the different regions studied between 250 and 1400 minutes, what seems to confirm that the tracer is little reversible. BP values obtained at 21 hours with occipital areas as reference and K_i/DV_ref values were respectively 4.62 ± 0.42 and 0.07 ± 0.01. The SPE classification according to BP and K_i/DV_ref values were similar to the classification according to the compartmental analysis (Kuhl 1994).The transient equilibrium model with late acquisition seems the more suitable because IBVM kinetic and practical simplicity of performing in clinical routine.     

Cinétique de dégradation des hydrocarbures par Candida lipolytica

Résumé Le mécanisme d'assimilation des hydrocarbures par une levure, Candida lipolytica est étudié au moyen de l'analyse cinétique de la croissance du microorganisme et de la disparition du substrat hydrocarboné. Les hydrocarbures utilisés sont des n-paraffines. On ajoute au milieu soit un seul hydrocarbure (n-tetradécane ou n-hexadécane), soit un mélange binaire (n-dodécane et n-heptadécane), soit un mélange complexe (du n-undécane au n-octadécane). Contrairement à d'autres auteurs, nous pensons qu'il est peu probable que l'essentiel de la réaction s'effectue par contact des gouttes de substrat et des microorganismes puisque l'on observe des retards d'assimilation de certains hydrocarbures: ceux de faible poids moléculaire (les plus solubles) sont assimilés plus rapidement. Il semble donc que l'assimilation se fasse en grande partie à partir d'hydrocarbures préablement solubilisés.

---

Kinetics of hydrocarbon assimilation by Candida lipolytica

Summary The mechanism of hydrocarbon uptake by a yeast, Candida lipolytica has been studied by means of the kinetic analysis of micro-organism growth and substrate assimilation. Hydrocarbons used as only source of carbon are normal alkanes either pure (n-tetradecane or n-hexadecane) or in mixture of two paraffins (n-dodecane and n-heptadecane) or eight paraffins (n-undecane to n-octadecane). In these last cases delays in n-alkanes consumption are observed. They show that the most soluble substrates (lower molecular weight) are first consumed. In opposition to other authors we think that there is little probability for main reaction occurring by direct contact between drops and micro-organisms. The evidence indicates that n-alkanes are mainly utilized in the dissolved state.

     

Preparation of 5′-O-(1-Thiotriphosphate)-Modified Oligonucleotides Using Polymerase-Endonuclease Amplification Reaction (PEAR)

Antisense oligonucleotides (ASODNs) have been widely used as an important tool for regulating gene expression, and developed into therapeutics. Natural ODNs are susceptible to nuclease degradation, nucleic acid analogues, however, have less side effects, stronger stability and more potent activities. Large-scale de novo synthesis of a certain oligonucleotide has been very difficult and costly. In a previous preliminary study, we developed the polymerase-endonuclease amplification reaction (PEAR) for amplification and large-scale preparation of natural antisense ODNs. Here we extended the method in preparation of a widely used modified oligonucleotide with 5′-O-(1-Thiotriphosphate) modifications. Using electrospray ionization liquid chromatography mass spectrometry (ESI/LC/MS) detection, the purity of the PEAR product was measured as high as 100.0%. Using PEAR a large amount of a specific oligonucleotide can be produced starting from a small amount of synthetic seeds. It is suggested that PEAR can be a useful tool for large-scale production of modified oligonucleotides.     

Etude olfactométrique de l'action de diverses substances allélochimiques végétales dans la recherche de l'hote par Diadromus pulchellus (Hymenoptera,Ichneumonidae)

Résumé La recherche de l'habitat d'un hôte potentiel par D. pulchellus, endoparasite considéré comme spécialiste des nymphes d'A. assectella, est abordée chez les adultes femelles et mâles, en olfactométrie, par l'étude de leur comportement locomoteur. L'activité locomotrice et l'attraction sont ainsi analysées en présence de substances allélochimiques issues ou non de végétaux pouvant abriter un hôte. Que les composés soufrés testés soient stables ou non, ils ne déclenchent pas d'attraction chez les hyménoptères quel que soit leur sexe et le type d'olfactomètre utilisé, contrairement aux imagos du phytophage-hôte, A. assectella, attirés par les composés soufrés instables spécifiques du poireau. L'activité locomotrice des hyménoptères des deux sexes est stimulée par divers composés volatils soufrés de synthèse ou émis naturellement par les Crucifères et par les Allium consommés par les larves d'A. assectella. Les substances efficaces sont généralément stables et sont caractérisées par le groupement actif R-S-, à condition que R ne soit pas un allyle. Par ailleurs, des composés volatils non soufrés contenus dans des végétaux autres que les Allium et les Crucifères ne stimulent pas le comportement locomoteur des hyménoptères. Ces différentes observations permettent d'envisager que D. pulchellus est un spécialiste inféodé à des microlépidoptères s'alimentant sur des végétaux soufrés et non sur les seuls Allium.

---

Summary Searching the host habitat by the endoparasite wasp Diadromus pulchellus, considered to be a specialist of Acrolepiopsis assectella nymphs, is studied in females and males by analysis of locomotory behaviour in olfactometers. Thus, locomotor activity and attraction are studied in the presence or absence of air-borne volatiles emitted by plants able to shelter a potential host-moth. Stable and unstable sulphur compounds used do not release attraction in female and male ichneumonids whatever the type of olfactometer used. By contrast, phytophagous host adults are attracted by unstable specific sulphur compounds of the leek. Locomotor activities of D. pulchellus females and males are stimulated by various volatile sulphur compounds of synthetic origin or naturally occurring in Allium eaten by A. assectella larvae and in Crucifera. The effective compounds generally are stable and characterized by the active group R-S — in which the alkyl moiety must not be an allyl one. On the other hand, volatiles without sulphur, emitted by plants which do not belong to Cruciferae or Allium, do not stimulate the hymenopteran locomotor activity. These observations suggest that D. pulchellus is oligophagous, attracted to microlepidoptera developing on plants containing sulphur compounds and not only on Allium.