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Mitochondrial homoplasmy, which is maintained by strictly maternal inheritance and a series of bottlenecks, is thought to be an adaptive condition for metazoans. Doubly uniparental inheritance (DUI) is a unique mode of mitochondrial transmission found in bivalve species, in which two distinct mitochondrial genome (mtDNA) lines are present, one inherited through eggs (F) and one through sperm (M). During development, the two lines segregate in a sex- and tissue-specific manner: females lose M during embryogenesis, whereas males actively segregate it in the germ line. These two pivotal events are still poorly characterized. Here we investigated mtDNA replication dynamics during embryogenesis and pre-adulthood of the venerid Ruditapes philippinarum using real-time quantitative PCR. We found that both mtDNAs do not detectably replicate during early embryogenesis, and that the M line might be lost from females around 24 h of age. A rise in mtDNA copy number was observed before the first reproductive season in both sexes, with the M mitochondrial genome replicating more than the F in males, and we associate these boosts to the early phase of gonad production. As evidence indicates that DUI relies on the same molecular machine of mitochondrial maternal inheritance that is common in most animals, our data are relevant not only to DUI but also to shed light on how differential segregations of mtDNA variants, in the same nuclear background, may be controlled during development.

The influence of cutting conditions of a low carbon martensitic stainless steel (15.5wt.% Cr, 4.8% Ni, 1% Mo, 0.9% Mn, 0.24% Si, 0.1% Cu, < 0.06% C and 77.46% Fe) on the microstructure is first studied using electron backscatter diffraction and transmission electron microscopy. The mechanical and corrosion behaviours of this stainless steel are then investigated. It was found that the microstructure is significantly affected near the machined surface. The formation of grain sub-boundaries or a refinement of the microstructure is observed depending on cutting conditions. Both lead to an increase of the hardness. In addition, the microstructure refinement yields to a huge increase of the average pit surface area. By contrast the average pit density is not affected by machining conditions.

Le diagnostic des fractures de poignet, notamment du scaphoïde, reste un défi en raison du risque de pseudarthrose. Des systèmes hybrides associant tomographie par émission monophotonique et tomodensitométrie (TEMP/TDM), combinant l’imagerie fonctionnelle et anatomique, sont actuellement disponibles. Nous avons souhaité évaluer les performances de la TEMP/TDM dans la prise en charge des fractures occultes du carpe.

L’usinage introduit un champ de contraintes résiduelles à la surface de l’échantillon et modifie la microstructure et la texture crystallographique dans un petit volume proche de la surface. L’influence de ces propriétés de surface sur l’évolution du courant anodique a été étudiée. L’évolution du potentiel libre de corrosion Ecorra été également analysée en considérant les caractéristiques de surface et la matrice de corrélation de Pearson. Ecorrest décalé dans la direction anodique en augmentant la contrainte quadratique, la rugosité et la lubrification (classés selon leur influence décroissante). La probabilité d’initier des piqûres a été ensuite discuté en considérant le paramètre ΔE= EPiqûres− ECorr. Lorsque ce paramètre augmente, la probabilité d’initier des piqûres diminue. Pour la plupart des conditions d’usinage utilisée, la probabilité d’initier des piqûres est faible. En revanche, des conditions d’usinage conduisant à une diminution significative de la valeur de ΔEont été définies (échantillon 3). Dans ces conditions, le risque de corrosion par piqûres est plus élevé.

Water and solute transport in the efferent ducts and epididymis are important for the establishment of the appropriate luminal environment for sperm maturation and storage. Aquaporin 9 (AQP9) is the main water channel in the epididymis, but its regulation is still poorly understood. Components of the kinin-kallikrein system (KKS), leading to the production of bradykinin (BK), are highly expressed in the lumen of the male reproductive tract. We report here that the epididymal luminal fluid contains a significant amount of BK (2 nM). RT-PCR performed on epididymal epithelial cells isolated by laser capture microdissection (LCM) showed abundant BK type 2 receptor (Bdkrb2) mRNA expression but no type 1 receptor (Bdkrb1). Double-immunofluorescence staining for BDKRB2 and the anion exchanger AE2 (a marker of efferent duct ciliated cells) or the V-ATPase E subunit, official symbol ATP6V1E1 (a marker of epididymal clear cells), showed that BDKRB2 is expressed in the apical pole of nonciliated cells (efferent ducts) and principal cells (epididymis). Triple labeling for BDKRB2, AQP9, and ATP6V1E1 showed that BDKRB2 and AQP9 colocalize in the apical stereocilia of principal cells in the cauda epididymidis. While uniform Bdkrb2mRNA expression was detected in the efferent ducts and along the epididymal tubule, marked variations were detected at the protein level. BDKRB2 was highest in the efferent ducts and cauda epididymidis, intermediate in the distal initial segment, moderate in the corpus, and undetectable in the proximal initial segment and the caput. Functional assays on tubules isolated from the distal initial segments showed that BK significantly increased AQP9-dependent glycerol apical membrane permeability. This effect was inhibited by BAPTA-AM, demonstrating the participation of calcium in this process. This study, therefore, identifies BK as an important regulator of AQP9.

In the epididymis and vas deferens, the vacuolar H+ATPase (V-ATPase), located in the apical pole of narrow and clear cells, is required to establish an acidic luminal pH. Low pH is important for the maturation of sperm and their storage in a quiescent state. The V-ATPase also participates in the acidification of intracellular organelles. The V-ATPase contains many subunits, and several of these subunits have multiple isoforms. So far, only subunits ATP6V1B1, ATP6V1B2, and ATP6V1E2, previously identified as B1, B2, and E subunits, have been described in the rat epididymis. Here, we report the localization of V-ATPase subunit isoforms ATP6V1A, ATP6V1C1, ATP6V1C2, ATP6V1G1, ATP6V1G3, ATP6V0A1, ATP6V0A2, ATP6V0A4, ATP6V0D1, and ATP6V0D2, previously labeled A, C1, C2, G1, G3, a1, a2, a4, d1, and d2, in epithelial cells of the rat epididymis and vas deferens. Narrow and clear cells showed a strong apical staining for all subunits, except the ATP6V0A2 isoform. Subunits ATP6V0A2 and ATP6V1A were detected in intracellular structures closely associated but not identical to the TGN of principal cells and narrow/clear cells, and subunit ATP6V0D1 was strongly expressed in the apical membrane of principal cells in the apparent absence of other V-ATPase subunits. In conclusion, more than one isoform of subunits ATP6V1C, ATP6V1G, ATP6V0A, and ATP6V0D of the V-ATPase are present in the epididymal and vas deferens epithelium. Our results confirm that narrow and clear cells are well fit for active proton secretion. In addition, the diverse functions of the V-ATPase may be established through the utilization of specific subunit isoforms. In principal cells, the ATP6V0D1 isoform may have a physiological function that is distinct from its role in proton transport via the V-ATPase complex.

Ellipticine derivatives have potential as anticancer drugs. Their clinical use has been limited, however, by poor solubility and host toxicity. As N-(2-hydroxypropyl)methacrylamide (HPMA) copolymer−anticancer conjugates are showing promise in early clinical trials, a series of novel HPMA copolymer conjugates have been prepared containing the 6-(3-aminopropyl)-ellipticine derivative (APE, NSC176328). Drug was linked to the polymer via GFLG or GG peptide side chains. To optimize biological behavior, HPMA copolymer-GFLG−APE conjugates with different drug loading (total APE:  2.3−7% w/w; free APE:  &lt;0.1% w/w) were synthesized. Conjugation of APE to HPMA copolymers considerably increased its aqueous solubility (>10-fold). HPMA copolymer-GG−APE did not liberate drug in the presence of isolated lysosomal enzymes (tritosomes), but HPMA copolymer-GFLG−APE released APE to a maximum of 60% after 5 h. The rate of drug release was influenced by drug loading; lower loading led to greater release. Whereas free APE (35 μg/mL) caused significant hemolysis (50% after 1 h), HPMA copolymer−APE conjugates were not hemolytic up to 300 μg/mL (APE-equiv). As would be expected from its cellular pharmacokinetics, HPMA copolymer-GFLG−APE was >75 times less cytotoxic than free drug (IC50 ~ 0.4 μg/mL) against B16F10 melanoma in vitro. However, in vivo when tested in mice bearing s.c. B16F10 melanoma, HPMA copolymer-GFLG−APE (1−10 mg/kg single dose, APE-equiv) given i.p. was somewhat more active (highest T/C value of 143%) than free APE (1 mg/kg) (T/C =127%). HPMA copolymer−APE conjugates warrant further evaluation as potential anticancer agents.

Abstract:  Active proton secretion and bicarbonate reabsorption by epithelial cells of the mammalian excurrent duct system maintains an acidic luminal pH that is involved in creating a suitable environment for sperm maturation and storage. Both an apical Na/H exchanger and an apical H+ATPase have been implicated in luminal acidification. The H+ATPase is located in apical and/or narrow cells in the caput epididymidis, and clear cells in the corpus and cauda epididymidis. As a step toward understanding the acute and chronic regulation of luminal acidification in excurrent ducts, we have followed the appearance of H+ATPase-rich cells in rat epididymis during postnatal development, using antibodies to subunits of the H+ATPase. In addition, we performed double staining with antibodies against carbonic anhydrase type II (CAII). H+ATPase-rich cells were already detectable 2 weeks after birth in all regions of the epididymis, and reached maximum numbers after 3–4 weeks. CAII-rich cells followed a similar developmental pattern. In adult rats, the number of H+ATPase/CAII-positive cells in the cauda was on average more than double the number in the caput epididymidis, although considerable intertubule variability was seen in both regions. Double immunostaining showed that CAII and H+ATPase were colocalized in the same cells in the caput and cauda, but H+ATPase-rich cells in the corpus contained low levels of CAII. These results demonstrate that differentiated subpopulations of proton-secreting epithelial cells appear early during epididymal development, and that the induction of H+ATPase in these cells occurs prior to sexual maturation.

Abstract.: Collapsed proximal convoluted tubules (PCT) shrink to reach a volume 20% lower than control and do not exhibit regulatory volume increase when submitted to abrupt 150 mOsm/kg hypertonic shock. The shrinking is accompanied by a rapid depolarization of the basolateral membrane potential (V BL) of 8.4 ± 0.5 mV, with respect to a control value of −54.5 ± 1.9 mV (n= 15). After a small and transient hyperpolarization, V BL further depolarizes to reach a steady depolarization of 19.5 ± 1.5 mV (n= 15) with respect to control. In the post-control period, V BL returns to −55.8 ± 1.5 mV. The basolateral partial conductance to K+ (t K ) which is 0.17 ± 0.01 (n= 5) in control condition, decreases rapidly to nonmeasurable values during the hypertonic shock and returns to 0.23 ± 0.03 in the post-control period. The basolateral partial conductance to Cl− (t Cl), which is 0.05 ± 0.02 (n= 5) in control, also decreases in hypertonicity to a nonmeasurable value and returns to 0.03 ± 0.01 in post control. The partial conductance mediated by the Na-HCO3 cotransporter (t NaHCO3), which is 0.48 ± 0.06 (n= 5) in control condition, remains the same at 0.44 ± 0.05 (n= 5) during the hypertonic period. Similarly, the membrane absolute conductance mediated by the Na-HCO3 cotransporter (G Na-HCO3) does not vary appreciably. Concomitant with cell shrinkage, intracellular pH (pH i ) decreases from a control value of 7.26 ± 0.01 to 7.13 ± 0.02 (n= 12) and then remains constant. Return to control solution brings back pH i to 7.28 ± 0.03. From these results, we conclude that in collapsed PCT, a sustained decrease in cellular volume leads to cell acidification and to inhibition of K+ and Cl− conductances.

Two solubleToxoplasma gondii antigen preparations were compared using the immunoblotting technique. The first preparation, which is commonly employed in ELISA tests, corresponds to a lytic extract of the parasite. The second known as exo-antigen, has yielded good results in cell immunity research and is obtained fromToxoplasma gondii culture supernatants. In both preparations, components exhibiting same molecular weight of 57–52 (doublet), 43, 38, 35, 30 and 20 kDa were revealed. In addition, two major 27- and 78-kDa components were detected in exo-antigens. The 30 kDa protein was intensely recognised by all sera, confirming the advantage of its use as an antigen in serological reactions. Exo-antigens could be employed as a soluble antigenic solution because they are easy to obtain, they display good antigenicity and their antigenic composition has been defined. Moreover their preparation does not require mouse inoculation. An evaluation of the enzyme-linked immunosorbent assays (ELISAs) involving these antigens has yet to be performed.

Three European directives imply for all member states an evaluation of food additives intakes. This paper describes the French approach, using a step-by-step procedure to evaluate, at a national level, the consumption of 10 food additives or groups of additives (E100, curcumin; E160b, annatto; E200-203, sorbic acid and salts; E210-213, benzoic acid and salts; E220-224, 226-228, sulphites; E249-250, nitrites; E297, fumaric acid; E473-474, sucrose esters and sucroglycerides; E491-492, stearoyl lactates; E952, cyclamic acid). The results are reassuring for the general population, except for sulphites.

Initial rates of Na(+)-dependent L-glutamic and D-aspartic acid uptake were determined at various substrate concentrations using a fast sampling, rapid filtration apparatus, and the resulting data were analyzed by nonlinear computer fitting to various transport models. At pH 6.0, L-glutamic acid transport was best accounted for by the presence of both high (Km = 61 microM) and low (Km = 7.0 mM) affinity pathways, whereas D-aspartic acid transport was restricted to a single high affinity route (Km = 80 microM). Excess D-aspartic acid and L-phenylalanine served to isolate L-glutamic acid flux through the remaining low and high affinity systems, respectively. Inhibition studies of other amino acids and analogs allowed us to identify the high affinity pathway as the X-AG system and the low affinity one as the intestinal NBB system. The pH dependences of the high and low affinity pathways of L-glutamic acid transport also allowed us to establish some relationship between the NBB and the more classical ASC system. Finally, these studies also revealed a heterotropic activation of the intestinal X-AG transport system by all neutral amino acids but glycine through an apparent activation of Vmax.

Les myopathies inflammatoires de l’enfant sont un groupe très hétérogène de pathologies tant sur le plan clinique que anatomopathologique ou biologique. L’objectif de ce travail est de colliger des cas pédiatriques de myosite de chevauchement afin d’améliorer leur description et leur classification.

Rapporter les résultats postopératoires et à long terme de la chirurgie œsogastrique pour cancer à visée curative.

La dermatomyosite juvénile (DMJ) ou les syndromes de chevauchement (SC) ont pour traitement de référence la corticothérapie par voie générale (CO), associé si besoin à des traitements immunosuppresseurs. Les immunoglobulines intraveineuses (IgIv) ont été récemment proposées en deuxième intention dans le traitement de la DMJ et dans la dermatomyosite amyopathique. Nous rapportons l’efficacité des IgIv dans 4 cas de DMJ lors de rechutes paucisymptomatiques diagnostiquées à l’IRM.