Hemerodromia Seguyi,nouvel empidide d'Algérie destructeur de simulies

Résumé Dans une précédente note ont été étudiés les premiers stades d'un Empidide d'Algérie, de la sous-famille des Atalantinae, Roederella ouedorum, dont les larves, rhéophiles, détruisent les larves et surtout les nymphes de Simulium sp. Un autre Empidide d'Algérie, de la sous-famille des Hemerodromiinae, Hemerodromia seguyi, dont la larve, la nymphe et l'imago sont décrites ici, a un mode de vie tout à fait analogue; sa larve vit au sein des colonies de larves de Simulies; ces dernières sont capturées et sucées par la larve prédatrice. La nymphe d'Hemerodromia seguyi est nue et fixée sous des pierres immergées, dans des zônes de courant faible.Summary In a swift stream of the Aures mountains (Algeria), were collected, on April 1950, a large number of larvae of an Empidid fly of the subfamily Hemerodromiinae: Hemerodromia (Metachela) seguyi n. sp.; they live on immerged rocks, among larvae of Simulium sp., upon which they prey; when feeding, the Empidid larva buries its head in its prey and sucks up the flesh. Pupation takes place usually in crevices of immerged rocks at the water's edge, where the current is slow.The larva and pupa of H. seguyi have been compared respectively to those of Roederella ouedorum, an Empidid fly belonging to the subfamily Atalantinae. The main differences between the larvae are not furnished by the head structure, but by the number of abdominal prolegs, the disposition of hooks on them and the form of the prominence at the end of the body. Pupae of Hemerodromia are easy to distinguish from pupae of other Empidids, for they have eight pairs of long tracheal filaments; other taxonomic characters are the form of the plates of the head on ventral aspect and the disposition of spines on the abdomen.     

Organometallic derivatives of estradiol as bioligands: targetted binding of the estradiol receptor

The complexation of estrogens by transitional metal units e.g. (alkyne)Co2(CO)6 and (alkyne)Mo2Cp2(CO)4, at the 17 alpha-position brings about a dramatic change in the chemical behavior of these compounds with respect to that of the free ligands. The 17 beta-OH function becomes particularly labile, even in weakly acidic medium, giving rise to carbenium ion-like species, from which, depending on the metal and the nucleophile, substitution, elimination and rearrangement take place. This situation provides the basis for a new type of active site directed-reagent for estradiol receptor. The hypothesis of vicinal space positioning of an acidic and a nucleophilic group in the estradiol receptor cavity is examined in the light of the amino-acid composition of the steroid binding domain. The requirement of the sulfhydryl group of a cysteine residue is suspected in the first step of the receptor inactivation process.     

A multicentre randomized controlled trial of the efficacy and safety of single-dose praziquantel at 40 mg/kg vs. 60 mg/kg for treating intestinal schistosomiasis in the Philippines, Mauritania, Tanzania and Brazil

Background

Praziquantel at 40 mg/kg in a single dose is the WHO recommended treatment for all forms of schistosomiasis, but 60 mg/kg is also deployed nationally.

Methodology/Principal Findings

Four trial sites in the Philippines, Mauritania, Tanzania and Brazil enrolled 856 patients using a common protocol, who were randomised to receive praziquantel 40 mg/kg (n = 428) or 60 mg/kg (n = 428). While the sites differed for transmission and infection intensities (highest in Tanzania and lowest in Mauritania), no bias or heterogeneity across sites was detected for the main efficacy outcomes. The primary efficacy analysis was the comparison of cure rates on Day 21 in the intent-to-treat population for the pooled data using a logistic model to calculate Odd Ratios allowing for baseline characteristics and study site. Both doses were highly effective: the Day 21 cure rates were 91.7% (86.6%–98% at individual sites) with 40 mg/kg and 92.8% (88%–97%) with 60 mg/kg. Secondary parameters were eggs reduction rates (ERR), change in intensity of infection and reinfection rates at 6 and 12 months. On Day 21 the pooled estimate of the ERR was 91% in both arms. The Hazard Ratio for reinfections was only significant in Brazil, and in favour of 60 mg/kg on the pooled estimate (40 mg/kg: 34.3%, 60 mg/kg: 23.9%, HR = 0.78, 95%CI = [0.63;0.96]). Analysis of safety could not distinguish between disease- and drug-related events. 666 patients (78%) reported 1327 adverse events (AE) 4 h post-dosing. The risk of having at least one AE was higher in the 60 than in the 40 mg/kg group (83% vs. 73%, p<0.001). At 24 h post-dosing, 456 patients (54%) had 918 AEs with no difference between arms. The most frequent AE was abdominal pain at both 4 h and 24 h (40% and 24%).

Conclusion

A higher dose of 60 mg/kg of praziquantel offers no significant efficacy advantage over standard 40 mg/kg for treating intestinal schistosomiasis caused by either S. mansoni or S. japonicum. The results of this study support WHO recommendation and should be used to inform policy decisions in the countries.

Trial Registration

Controlled-Trials.com ISRCTN29273316 ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT00403611","term_id":"NCT00403611"}}NCT00403611     

Effects of general,specific and combined warm-up on explosive muscular performance

The purpose of this study was to compare the acute effects of general, specific and combined warm-up (WU) on explosive performance. Healthy male (n = 10) subjects participated in six WU protocols in a crossover randomized study design. Protocols were: passive rest (PR; 15 min of passive rest), running (Run; 5 min of running at 70% of maximum heart rate), stretching (STR; 5 min of static stretching exercise), jumping [Jump; 5 min of jumping exercises – 3x8 countermovement jumps (CMJ) and 3x8 drop jumps from 60 cm (DJ60)], and combined (COM; protocols Run+STR+Jump combined). Immediately before and after each WU, subjects were assessed for explosive concentric-only (i.e. squat jump – SJ), slow stretch-shortening cycle (i.e. CMJ), fast stretch-shortening cycle (i.e. DJ60) and contact time (CT) muscle performance. PR significantly reduced SJ performance (p =0.007). Run increased SJ (p =0.0001) and CMJ (p =0.002). STR increased CMJ (p =0.048). Specific WU (i.e. Jump) increased SJ (p =0.001), CMJ (p =0.028) and DJ60 (p =0.006) performance. COM increased CMJ performance (p =0.006). Jump was superior in SJ performance vs. PR (p =0.001). Jump reduced (p =0.03) CT in DJ60. In conclusion, general, specific and combined WU increase slow stretch-shortening cycle (SSC) muscle performance, but only specific WU increases fast SSC muscle performance. Therefore, to increase fast SSC performance, specific fast SSC muscle actions must be included during the WU.     

Wavelet Analysis of DNA Bending Profiles reveals Structural Constraints on the Evolution of Genomic Sequences

Analyses of genomic DNA sequences have shown in previous works that base pairs are correlated at large distances with scale-invariant statistical properties. We show in the present study that these correlations between nucleotides (letters) result in fact from long-range correlations (LRC) between sequence-dependent DNA structural elements (words) involved in the packaging of DNA in chromatin. Using the wavelet transform technique, we perform a comparative analysis of the DNA text and of the corresponding bending profiles generated with curvature tables based on nucleosome positioning data. This exploration through the optics of the so-called `wavelet transform microscope' reveals a characteristic scale of 100-200 bp that separates two regimes of different LRC. We focus here on the existence of LRC in the small-scale regime ( 200 bp). Analysis of genomes in the three kingdoms reveals that this regime is specifically associated to the presence of nucleosomes. Indeed, small scale LRC are observed in eukaryotic genomes and to a less extent in archaeal genomes, in contrast with their absence in eubacterial genomes. Similarly, this regime is observed in eukaryotic but not in bacterial viral DNA genomes. There is one exception for genomes of Poxviruses, the only animal DNA viruses that do not replicate in the cell nucleus and do not present small scale LRC. Furthermore, no small scale LRC are detected in the genomes of all examined RNA viruses, with one exception in the case of retroviruses. Altogether, these results strongly suggest that small-scale LRC are a signature of the nucleosomal structure. Finally, we discuss possible interpretations of these small-scale LRC in terms of the mechanisms that govern the positioning, the stability and the dynamics of the nucleosomes along the DNA chain. This paper is maily devoted to a pedagogical presentation of the theoretical concepts and physical methods which are well suited to perform a statistical analysis of genomic sequences. We review the results obtained with the so-called wavelet-based multifractal analysis when investigating the DNA sequences of various organisms in the three kingdoms. Some of these results have been announced in B. Audit et al. [1, 2].     

Cellular localization of intrinsic factor in pancreas and stomach of the dog

Summary A cobalamin (vitamin B₁₂)-binding protein has recently been identified in canine pancreatic juice which is biochemically, immunochemically and functionally similar to canine gastric intrinsic factor. However, the cellular sources of both this pancreatic intrinsic factor and gastric intrinsic factor in the dog are not known. Antisera raised against canine gastric intrinsic factor have been used to examine the distribution of intrinsic factors in the canine pancreas and stomach. Immunoreactivity was demonstrated in duct cells but not acinar or endocrine cells in the pancreas, and in fundic peptic and pyloric gastric pit cells in stomach. All immunostaining was abolished by preabsorption of the antisera with purified canine gastric and pancreatic intrinsic factors. A cellular source of pancreatic intrinsic factor has not been previously described, and the demonstration of intrinsic factor-like immunoreactivity in two cell types in the canine stomach contrasts with its localization in a single cell type in the gastric mucosa of other mammalian species. Furthermore, immunoreactivity in pancreatic duct cells was detected at much higher dilutions of antisera than those required for staining of peptic and gastric pit cells. This suggests a higher concentration of antigen, and supports previous evidence that the pancreas is a major source of intrinsic factor in the dog.     

Interactions ofCandida albicans with bacteria and salivary molecules in oral biofilms

The yeastCandida albicans coaggregates with a variety of streptococcal species, an interaction that may promote oral colonization by yeast cells.C. albicans andCandida tropicalis are the yeasts most frequently isolated from the human oral cavity and our data demonstrate that both these species bind toStreptococcus gordonii NCTC 7869 while two otherCandida species (Candida krusei andCandida kefyr) do not. Adherence ofC. albicans was greatest when the yeast had been grown at 30° C to mid-exponential growth phase. For 21 strains ofC. albicans there was a positive correlation between the ability to adhere toS. gordonii and adherence to experimental salivary pellicle. Whole saliva either stimulated or slightly inhibited adherence ofC. albicans toS. gordonii depending on the streptococcal growth conditions. The results suggest that the major salivary adhesins and coaggregation adhesins ofC. albicans are co-expressed.