Study of a Pendulum in Vivo Electromechanical Generator to be Used in a Knee Prosthesis

International audienceThis paper presents the principle and the energy potential of an original electromechanical generator that uses human body natural motions during walking, in order to create an autonomous generator. This in vivo and noninvasive system is intended to be used in intelligent knee prosthesis. As the combined human, mechanical, and electrical phenomena are very significant, a mechanical and an electrical study are then carried to evaluate the recoverable power

DFIG Driven Wind Turbine Grid Fault-Tolerance Using High-Order Sliding Mode Control

International audienceThis research note deals with grid fault-tolerance of a doubly-fed induction generator-based wind turbine using high-order sliding mode control. Indeed, it is proposed to assess the main and attractive features of high-order sliding modes which are robustness against external disturbances (e.g. grid) and chattering-free behavior (no extra mechanical stress on the drive train). Simulations using the NREL FAST code on a 1.5-MW wind turbine are carried-out to evaluate ride-through performances of high-order sliding mode control

A rapid enzymatic method for the isolation of defined kidney tubule fragments from mouse

The increasing number of available genetically manipulated mice makes it necessary to develop tools and techniques for examining the phenotypes of these animals. We have developed a straightforward and rapid method for the isolation of large quantities of single tubule fragments from the mouse kidney. Immunohistochemistry, electron microscopy, and fluorescence microscopy were used to evaluate the viability, functional characteristics, and morphology of proximal tubules (PT), and collecting ducts from cortex (CCD) and inner stripe of the outer medulla (ISOMCD). Tubules were isolated using a modified collagenase digestion technique, and selected under light microscopy for experimentation. Electron microscopy and trypan blue exclusion showed that a large portion of unselected proximal tubules were damaged by the digestion procedure. The selected tubules, however, all excluded trypan blue, indicating that the plasma membrane had remained intact. Immunocytochemistry on isolated CCD showed normal distribution of H+-ATPase, pendrin, and anion exchanger-1 (AE-1) staining. The pH-sensitive dye 2′,7′-bis(2-carboxylethyl)-5(6)-carboxyfluorescein (BCECF) was used to measure Na+-dependent and -independent intracellular pH (pHi) recovery rates in PT, and in single intercalated cells of CCD and ISOMCD fragments. Na+-dependent pHi-recovery was 0.144±0.008 (PT), 0.182±0.013 (CCD), and 0.112±0.010pH units/min. (ISOMCD). Na+-independent pHi recovery was found in all three segments (PT: 0.021±0.002, CCD: 0.037±0.002, ISOMCD: 0.033±0.002pH units/min) and was sensitive to concanamycin. In summary, we have developed a new technique for rapid and straightforward preparation of large quantities of defined tubule fragments from mouse kidney. Using this technique, the first measurements of plasma membrane vacuolar H+-ATPase activities in mouse PT and collecting duct were made. This technique will facilitate further characterization of kidney function in normal and genetically manipulated animal

Variant on Manifestation of Duodenal Metastasis 26 Years after Initial Diagnosis of Primary Cutaneous Melanoma

Malignant duodenal neoplasms are relatively rare, and the diagnosis is often delayed because of their vague and nonspecific symptoms. We report the case of a 79-year-old female who had a medical history of malignant melanoma of the cheek that had initially been diagnosed at 53 years of age. Work-up revealed severe stenosis of the duodenum caused by a large mass with ulceration at the tip of its mucosal surface. Tumor biopsy led to a histological diagnosis of extremely poorly differentiated carcinoma, but it was impossible to determine whether the lesion was a primary neoplasm or represented secondary involvement. Pancreatoduodenectomy was performed, and the surgical specimen showed a protuberant tumor in the nonampullary region of the second portion of the duodenum. Final diagnosis of metastatic duodenal melanoma was made by immunohistological examination. She is currently alive without recurrence 28 months after the surgical treatment

Caput Ligation Renders Immature Mouse Sperm Motile and Capable to Undergo cAMP-Dependent Phosphorylation

Mammalian sperm must undergo two post-testicular processes to become fertilization-competent: maturation in the male epididymis and capacitation in the female reproductive tract. While caput epididymal sperm are unable to move and have not yet acquired fertilization potential, sperm in the cauda epididymis have completed their maturation, can move actively, and have gained the ability to undergo capacitation in the female tract or in vitro. Due to the impossibility of mimicking sperm maturation in vitro, the molecular pathways underlying this process remain largely unknown. We aimed to investigate the use of caput epididymal ligation as a tool for the study of sperm maturation in mice. Our results indicate that after seven days of ligation, caput sperm gained motility and underwent molecular changes comparable with those observed for cauda mature sperm. Moreover, ligated caput sperm were able to activate pathways related to sperm capacitation. Despite these changes, ligated caput sperm were unable to fertilize in vitro. Our results suggest that transit through the epididymis is not required for the acquisition of motility and some capacitation-associated signaling but is essential for full epididymal maturation. Caput epididymal ligation is a useful tool for the study of the molecular pathways involved in the acquisition of sperm motility during maturation

CRISP (Cysteine Rich Secretory Proteins) as novel regulators of epididymal epithelium differentiation

Epididymal CRISP1 and CRISP4 associate with the sperm surface during maturation and are key mediators of fertilization. Whereas single knockout (KO) males for these molecules showed in vitro sperm fertilizing defects but normal fertility, all double KO (DKO) animals for these proteins exhibited impaired in vivo fertilization and fertility. In addition, one third of DKO showed bigger testes and epididymides not observed in single KO. Based on this, in the present work we investigated the mechanisms underlining this DKO phenotype. Histological studies of DKO testes and epididymides showed that whereas mice with normal tissues (Group 1) were not different from controls, those with bigger organs (Group 2) had clear histological defects as well as an abnormal presence of immune cells in the interstitium and lumen. RT-qPCR for different immunomodulator molecules revealed higher levels of Il-6 and Il-10 and a downregulation of Tgf-β in DKO from Group 2 not observed in Group 1. Interestingly, immunofluorescence experimentsusing specific markers for each of the different epididymal epithelial cells revealed fewer and shorter basal cell projections in the initial segment known as axiopodia, defects in principal cells and clear cells with an immature phenotype in both groups. Accompanying these epithelial changes, males from both groups also exhibited an increase in intraluminal pH. Altogether, these observations support the relevance of CRISP proteins for male fertility through their involvement in epididymal epithelium differentiation and luminal acidification which are critical for sperm maturation and storage.Fil: Carvajal, Guillermo. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Brukman, Nicolás Gastón. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Weigel Muñoz, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Battistone, Maria Agustina. Harvard Medical School; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Guazzone, Vanesa Anabella. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas; ArgentinaFil: Lustig, Livia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas; ArgentinaFil: Breton, Sylvie. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas; Argentina. Harvard Medical School; Estados UnidosFil: Cuasnicú, Patricia S.. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentina7th International Conference on the EpididymisMontrealCanadáEpididymis 7 Committe

Mapping the H+ (V)-ATPase interactome: identification of proteins involved in trafficking, folding, assembly and phosphorylation

V-ATPases (H+ ATPases) are multisubunit, ATP-dependent proton pumps that regulate pH homeostasis in virtually all eukaryotes. They are involved in key cell biological processes including vesicle trafficking, endosomal pH sensing, membrane fusion and intracellular signaling. They also have critical systemic roles in renal acid excretion and blood pH balance, male fertility, bone remodeling, synaptic transmission, olfaction and hearing. Furthermore, V-ATPase dysfunction either results in or aggravates various other diseases, but little is known about the complex protein interactions that regulate these varied V-ATPase functions. Therefore, we performed a proteomic analysis to identify V-ATPase associated proteins and construct a V-ATPase interactome. Our analysis using kidney tissue revealed V-ATPase-associated protein clusters involved in protein quality control, complex assembly and intracellular trafficking. ARHGEF7, DMXL1, EZR, NCOA7, OXR1, RPS6KA3, SNX27 and 9 subunits of the chaperonin containing TCP1 complex (CCT) were found to interact with V-ATPase for the first time in this study. Knockdown of two interacting proteins, DMXL1 and WDR7, inhibited V-ATPase-mediated intracellular vesicle acidification in a kidney cell line, providing validation for the utility of our interactome as a screen for functionally important novel V-ATPase-regulating proteins. Our data, therefore, provide new insights and directions for the analysis of V-ATPase cell biology and (patho)physiology

The Forkhead Transcription Factor Foxi1 Is a Master Regulator of Vacuolar H+-ATPase Proton Pump Subunits in the Inner Ear, Kidney and Epididymis

The vacuolar H+-ATPase dependent transport of protons across cytoplasmic membranes in FORE (forkhead related) cells of endolymphatic epithelium in the inner ear, intercalated cells of collecting ducts in the kidney and in narrow and clear cells of epididymis require expression of several subunits that assemble into a functional multimeric proton pump. We demonstrate that expression of four such subunits A1, B1, E2 and a4 all co-localize with the forkhead transcription factor Foxi1 in a subset of epithelial cells at these three locations. In cells, of such epithelia, that lack Foxi1 we fail to identify any expression of A1, B1, E2 and a4 demonstrating an important role for the transcription factor Foxi1 in regulating subunit availability. Promoter reporter experiments, electrophoretic mobility shift assays (EMSA) and site directed mutagenesis demonstrate that a Foxi1 expression vector can trans-activate an a4-promoter reporter construct in a dose dependent manner. Furthermore, we demonstrate using chromatin immunoprecipitation (ChIP) assays that Foxi1-dependent activation to a large extent depends on cis-elements at position −561/−547 in the a4 promoter. Thus, we provide evidence that Foxi1 is necessary for expression of at least four subunits in three different epithelia and most likely is a major determinant for proper assembly of a functional vacuolar H+-ATPase complex at these locations