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Worldwide incidence of kidney diseases has been rising. Thus, recent research has focused on zebrafish, whose fast development and innate regeneration capacity allow identifying factors influencing renal processes. Among these poorly studied factors are extracellular matrix (ECM) proteins like Fibronectin (Fn) essential in various tissues but not yet evaluated in a renal context. We utilized early nat and han zebrafish mutant embryos and carrier adults to investigate Fn's role during kidney development and regeneration. The locus natter (nat) encodes Fn and the locus han encodes Hand2, which results in increased Fn deposition. Our results show that Fn impacts identity maintenance and morphogenesis during development and influences conditions for neonephrogenic cluster formation during regeneration. Histological analysis revealed disrupted pronephric structures and increased blood cell accumulation in Fn mutants. Despite normal expression of specification markers (pax2, ATPα1a.1), structural abnormalities were evident. Differences between wild-type and mutation-carriers suggest a haploinsufficiency scenario. These findings reveal a novel function for ECM in renal development and regeneration, with potential implications for understanding and treating kidney diseases.

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This study aimed to describe pronephros and mesonephros morphology during the embryonic development of Podocnemis expansa. Eggs were collected on an artificial beach at Balbina, Amazonas, Brazil, during the entire incubation period (mean of 59 days). The kidney-gonad complex was processed using light microscopy and the mesonephros using transmission electron microscopy. The pronephros was present for the first time on stage 4, composed of external glomeruli devoid of a capsule, protruding into the coelomic cavity, and internally composed of a capillary network. The pronephros degenerated after development stage 15. The first sign of the appearance of the mesonephros occurred around stage 8, indicated by the early formation of renal corpuscles. The mesonephros comprised an renal corpuscles, neck segment, proximal tubule, intermediate segment, distal tubule, collector tubule, and collector duct. Ultrastructural analysis of the mesonephros brush border was done in the proximal tubule, and the presence of cells with structural characters indicative of secretory activity was detected in the juxtatubular region. Renal corpuscles and proximal tubules were the main components that underwent morphological alterations during mesonephros degeneration. The pronephros is a transient kidney, and the mesonephros became the functional embryonic kidney in P. expansa. Mesonephros degeneration occurs in the cranial-caudal direction, and histologically, the degeneration is identified by changes in the morphology of the renal corpuscle and proximal tubule. However, the mesonephros is still present after hatching.

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Intercellular communication orchestrates a multitude of physiologic and pathologic conditions. Algorithms to infer cell-cell communication and predict downstream signalling and regulatory networks are needed to illuminate mechanisms of stem cell differentiation and tissue development. Here, to fill this gap, we developed and applied CellComm to investigate how the aorta-gonad-mesonephros microenvironment dictates haematopoietic stem and progenitor cell emergence. We identified key microenvironmental signals and transcriptional networks that regulate haematopoietic development, including Stat3, Nr0b2, Ybx1 and App, and confirmed their roles using zebrafish, mouse and human models. Notably, CellComm revealed extensive crosstalk among signalling pathways and convergence on common transcriptional regulators, indicating a resilient developmental programme that ensures dynamic adaptation to changes in the embryonic environment. Our work provides an algorithm and data resource for the scientific community.

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The development of caenolestid marsupials (order Paucituberculata) is virtually unknown. We provide here the first description of Caenolestes fuliginosus embryos collected in the Colombian Central Andes. Our sample of four embryos comes from a single female caught during a fieldtrip at Río Blanco (Manizales, Caldas), in 2014. The sample was processed for macroscopic description using a Standard Event System and for histological descriptions (sectioning and staining). The grade of development of the lumbar flexure and coelomic closure differed between embryos, two of them being more advanced than the others (similar to McCrady's stages 30 and 29, respectively). The pericardial and peritoneal cavities were present, the hepatic anlage was organized in hepatic cords, the heart was in its final position, and the mesonephros was functional. Compared to other Neotropical marsupials, an early appearance of the frontonasal-maxillary fusion and the cervical growth (thickness) was observed; however, absorption of the pharyngeal arches into the body and lung development was delayed. Besides these differences, embryos were similar to equivalent stages in Didelphis virginiana and Monodelphis domestica. Previous proposals of litter size of four for C. fuliginosus are supported.

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BACKGROUND: The mechanisms by which the rete testis joins the efferent ducts, which joins the Wolffian duct during development, are not known. Mouse and chick models have been helpful in identifying genes that are important for the development of each part, but genes have not been identified as to those that play a role in the joining of each part. Clinical implications of the failure of the male reproductive tract to form a fully functional conduit for spermatozoa are not trivial. Epididymal disjunction, the failure of the efferent ducts to join the testis, is one of several epididymal anomalies that have been observed in some boys who were cryptorchid at birth. OBJECTIVE: A systematic review of studies focusing on the morphogenesis of the mesonephric duct and mesonephric tubules in different species, and identification of clinical issues should there be failure of these tissues to develop. DESIGN: PubMed and GUDMAP databases, and review of books on kidney development were searched for studies reporting on the mechanisms of morphogenesis of the kidney and epididymis. MAIN OUTCOMES MEASURE(S): Gaps in our knowledge were identified, and hypotheses coupled with suggestions for future experiments were presented. RESULTS: A total of 64 papers were identified as relevant, of which 53 were original research articles and 11 were book chapters and reviews covering morphogenesis and clinical issues. Investigators utilized multiple species including, human, mouse, chick, Xenopus, bovine, and sheep. CONCLUSION: Fundamental understanding of the morphogenesis of the male reproductive tract is limited, especially the morphogenesis of the rete testis and efferent ducts. Therefore, it is not surprising that we do not understand how each part unites to form a whole. Only one mechanism of joining of one part of the tract to another was identified: the joining of the Wolffian duct to the cloaca via controlled apoptosis.

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The embryonic origin of the urogenital system came from the intermediate mesoderm. Kidney development involves three successive renal systems with a fast chronological overlap: the pronephro, the mesonephro, and the metanephro. Due to the lack of specific knowledge about this system in cats the present work aimed to describe their urinary organs development, focusing on the structures seen in pronephro, mesonephro, and metanephro during the embryonic and fetal stages of development. The techniques used in this study were: light microscopy, immunohistochemistry, scanning electron microscopy, and transmission electron microscopy. For that, embryos and fetuses from 12 pregnant mixed-breed domestic cats in different gestational stages were used to describe the proposed organs. The pronephro is present at early stages of embryonary development in embryos from 15 to 19 days with the presence of pronephro's corpuscles, ducts and tubules. The mesonephro is found, in general, between days 17 and 37, and contains mesonephric ducts, mesonephric tubules, and glomeruli. The metanephro is seen since 21 days of pregnancy with the presence of glomeruli, proximal and distal contorted tubules and at day 37, the cortex-medullary region is already differentiated. The evaluation of these structures enhances the knowledge about embryology of the urinary system in cats, aiding a better anatomical understanding of the system in the specie allowing the correlation with other species.

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Mast cells originate from pluripotent hematopoietic stem cells. Two mast cell specific antibodies, mAbsAA4 and BGD6, have previously been used to identify and study committed mast cell precursors (MCcps) in the bone marrow of adult mice and rats. However, the embryonic origin of MCcps is still not known. In the present study, we identified MCcps in rat embryos using these previously characterized mast cell specific antibodies. The MCcps were found in the AGM (aorta-gonad-mesonephros) region of rat embryos at E11.5. These cells were BGD6+, CD34(+), c-kit(+), CD13(+), FcεRI(-), AA4(-) CD40(-), and Thy-1(-). By PCR the cells contained message for the α and ß subunits of FcεRI and mast cell specific proteases. In vitro, the MCcps differentiated into metachromatic mast cells. With age of gestation the percent of MCcps diminished while the percent of mast cell progenitors increased. An increased knowledge of the biology and embryonic origin of mast cells may contribute to a greater understanding of allergy, asthma, and other mast cell related diseases.

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O estudo objetivou caracterizar o desenvolvimento morfológico e organológico de embriões suínos da raça Landrace (Sus scrofa domesticus) aos 20 (n=6) e 30 (n=7) dias pós inseminação artificial (p.i.), utilizando técnicas macroscópicas e microscópicas, além da análise morfométrica dos principais órgãos (coração, pulmão, fígado e mesonefro), inferindo sua importância na manutenção do concepto. [...] A comparação entre as médias das áreas totais do coração, fígado e mesonefro, pelo teste Mann-Whitney, indicaram que os embriões, aos 20 e 30 dias p.i., apresentaram diferença significativa (p<0,05). Este estudo sugeriu que a taxa de uniformidade e desenvolvimento dos embriões podem ser determinantes para a manutenção do concepto durante o período gestacional. Porém, mais estudos são necessários para elucidar os mecanismos acerca do desenvolvimento embrionário no terço inicial da gestação a fim de minimizar as perdas gestacionais na espécie suína

The study aimed to characterize the morphological and organology development of Landrace pigs embryos (Sus scrofa domesticus) at 20 days (n=6) and 30 days (n=6) post artificial insemination (p.i.) through macroscopic and microscopic techniques, besides morphometric analysis of the major organs (heart, lung, liver and mesonephros) inferring its importance in the conseptus maintenance. [...] The comparison between the means of the total areas of the heart, liver and mesonephros, through Man-Whitney test indicated that the embryos at 20 and 30 days p.i., demonstrated significant differences (p<0,05). This study suggested that the embryo uniformity and development rate may be crucial in the maintenance of the conceptus during the gestational period. However, more studies are necessary to elucidate the mechanisms of the embryonic development regarding the first third of pregnancy in order to minimize gestational losses in swine

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Se estudia una muestra de 19 embriones humanos comprendidos entre la quinta y la octava semana de desarrollo, con el objetivo de conocer algunas características morfológica cuantitativas de la cresta urogenital. Los embriones fueron fijados previamente en solución de formaldehido al 8 por ciento y procesados histológicamente mediante la técnica de parafina. El plano de corte fue el transversal. Se aplicó técnica morfométrica a través de programa COMSDI PLUS. Las variables estudiadas fueron, el área transversal de gónada, área transversal de mesonefros y área transversal de cresta urogenital en ambos lados. Se realizó el procesamiento estadístico mediante el sistema SPSS. Se comprueba la existencia de diferencias significativas entre las semanas estudiadas, con una tendencia a la estabilización hacia el final del período embrionario en todas las variables(AU)

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Se estudia una muestra de 19 embriones humanos comprendidos entre la quinta y la octava semana de desarrollo, con el objetivo de conocer algunas características morfológicas cuantitativas de la cresta urogenital. Los embriones fueron fijados previamente en solución de formaldehído al 8porciento y procesados histológicamente mediante la técnica de parafina. El plano de corte fue el transversal. Se aplicó técnica morfométrica a través de programa COMSDI PLUS. Las variables estudiadas fueron: el área transversal de gónada, área transversal de mesonefros y área transversal de cresta urogenital en ambos lados. Se realizó el procesamiento estadístico mediante el sistema SPSS. Se comprueba la existencia de diferencias significativas entre las semanas estudiadas, con una tendencia a la estabilización hacia el final del periodo embrionario en todas las variables(AU)

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We report a case of female adnexal tumour of probable wolffian origin, a rare tumour of the broad ligament, and discuss aspects of its origin, differential diagnosis and behaviour.(AU)

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No mesossalpinge, entre a trompa e o ovário, está situado o paraovário. Os cistos paraovarianos originam-se de estruturas vestigiais de Wolff, do epitélio tubário ou de incluções peritoneais. Raramente atinguem tamanho de cisto do próprio ovário. Os autores relatam um raro caso de cisto paraovariano gigante

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We report a case of female adnexal tumour of probable wolffian origin, a rare tumour of the broad ligament, and discuss aspects of its origin, differential diagnosis and behaviour.

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A study on the effects of He-Ne laser irradiation on glomeruli and renal tubules of the chick embryo mesonephros at 7 days of in ovo development was made. To this purpose, He-Ne laser irradiation (potency: 5 mW, wavelength: 632.8 nm) was beamed for 5 minutes through a window opened in the egg shell, and the eggs were maintained aseptically for 24 h in an incubator. Mesonephros were dissected out and processed for hematoxylin/eosin, periodic acid-Schiff, and Alcian blue at pH 2.5 and 1.0, toluidine Blue at pH 3.8. In controls, the glomeruli were formed by coiled capillaries with a homogeneous basement membrane, the proximal tubules presented a high cubic epithelium with acidophilic cytoplasm and a developed brush border. Distal and collecting segments were lined by cubic epithelium. An alcianophilic and PAS-positive reaction stood out at the membrane coats of the proximal tubules and tubular and glomerular basement membranes. No glomerular alterations were observed during the experiment. However, there was a marked enlargement of the tubular interstitium, with edema and lymphohistiocytic inflammatory infiltration. Some tubular cells desquamated to the lumen. Other cells presented a raveled apical surface. Some nuclei were dispersed out, and mixing with chromatin, formed diminutive granules. Pyknotic nuclei were seen occasionally. Epithelial necrosis and cytoplasmic debris in the lumen were also noted. For mucins, some zones showed brush border coats of the proximal tubules as discontinuous.(ABSTRACT TRUNCATED AT 250 WORDS)

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The ontogeny of immunoglobulin (Ig) synthesis was followed at both cellular and serological levels in the Mexican axolotl (Ambystoma mexicanum) using polyclonal antibodies recognizing all Ig molecules and a set of monoclonal antibodies (Mabs) specific for the C mu and Cv heavy Ig chain isotypes and for the light chain constituents shared by IgM and IgY molecules. Clusters of IgM- and of IgY-synthesizing lymphocytes, often located in separate sites, are first present in spleen sections of 7-week-old 25 mm larvae, about one month after differentiation of the spleen anlage (stage 39-40). In 12-week-old 30-35 mm larvae, the relative proportion of IgM- and IgY-synthesizing cells in the spleen is the same as that in adult animals. However, a marked enhancement of the spleen B cell compartment occurs from 5 to 9 months when Ig-positive cells represent about 88% of the lymphocytes population compared to 60% in adults. No structures equivalent to B cell germinal centers were observed at any stage of the spleen differentiation and cells, although often clustered in small groups, remain dispersed in the entire organ. The relative proportions of IgM and IgY B cells throughout the spleen remain constant during development (about 1 IgY+ cell for 5-6 IgM+ cells) and IgM molecules are first detected in the serum of 2.5-month-old larvae. The enhancement of the serum IgM level correlates well with the absolute number of IgM+ cells in the growing spleen. IgY molecules cannot be detected in the serum before the 7th month but their level quickly increases to reach about 60% of the adult value at 10 months. Thyroxine-induced metamorphosis or hyperimmunization of 4- to 6-month-old larvae had no effect upon the temporal expression of the Ig classes in serum.

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The presence of insulin the brush border and apical pole of the cells lining the pouch opossum mesonephric and metanephric proximal tubules was demonstrated by immunofluorescence and immunoperoxidase techniques. Positive result for insulin was also observed in the tufts of capillaries of some metanephric corpuscles.

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Realizado el estudio, del presente trabajo, podemos sacar las siguientes conclusiones, 1.- En los casos en que la reacciòn fuè negativa no encontramos gramos de hemozoina en ninguna de las placas respectivas, 2.- Hipotèticamente, la reacciòn es producida por la presipitaciòn de la hemozoina por el reactivo, 3.- El ìndice de positividad de la reacciòn es de 97,2 porciento, 4.-En los individuos que hayan enfermado paludismo y recibido un tratamiento intenso, el resultado de la reacciòn es siempre negativo, 5.- Por su facìl realizaciòn y pequeño costo econòmico, se la recomienda como una reaccion de rutina

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