China
Africa
Explore chapters and articles related to this topic
Late-Gestation and Third Trimester
Published in Mary C. Peavey, Sarah K. Dotters-Katz, Ultrasound of Mouse Fetal Development and Human Correlates, 2021
Mary C. Peavey, Sarah K. Dotters-Katz
The urinary system, comprised of the kidneys, ureters, bladder and urethra are responsible for the production and release of urine (2). Mammalian renal development which includes the differentiation from pronephros, mesonephros, and metanephros; the metanephros persists as the definitive adult kidney, and has a branched collecting duct system and many nephrons (3,4).
Molecular Approaches Towards the Isolation of Pediatric Cancer Predisposition Genes
Published in John T. Kemshead, Pediatric Tumors: Immunological and Molecular Markers, 2020
Wilms’ tumor is not the only malignancy associated with 11p deletion and the AGR triad. Andersen et al.78 reported one AGR patient, a girl, who developed bilateral gonadoblastoma at 21 months. Particularly interesting is that both the kidneys and gonads are of mesodermal origin and derive from embryologically adjacent structure involving the mesonephros. These observations imply that genes in 11p13 must act pleiotrophically, and affect development of a number of different tissues (see later).
The urinary and reproductive systems and the external genitalia
Published in Frank J. Dye, Human Life Before Birth, 2019
The second type of kidney to arise is the mesonephros. Another series of tubules arises from intermediate mesoderm on each side of the body, this time caudal to the level of the pronephros. These mesonephric tubules grow dorsad and join the pronephric ducts, which will now be referred to as mesonephric ducts. These ducts extend back to the level of the cloaca, where they bend ventrad and open into the portion of the cloaca that becomes the urogenital sinus (see Figure 18.1). The mesonephros functions during the late embryonic and early fetal periods.
Advances in understanding vertebrate nephrogenesis
Published in Tissue Barriers, 2020
Joseph M. Chambers, Rebecca A. Wingert
Following IM specification, the progression of vertebrate renal development involves the stepwise generation and degeneration of several kidney forms: the pronephros, mesonephros, and metanephros. Each kidney iteration develops along the anterior-posterior embryonic axis, where each subsequent version becomes more structurally complex than the previous structure. The pronephros emerges first, and while it is vestigial/nonfunctional in mammals, it is functional in other vertebrates such as fish and frogs.23 The mesonephros is further developed and partially functional in mammals, while serving as the final kidney form in amphibians and fish.24 However, the fully formed and functional version of this vital organ in mammals is the metanephros, which develops through branching morphogenesis events that result in an arborized structure essential for fluid homeostasis. Importantly, all three vertebrate kidney forms share the overall structure of the kidney’s functional unit: the nephron. Broadly, the nephron is composed of a blood filter, a segmented tubule, and a collecting duct system to shuttle urine to the bladder.
Cathelicidin attenuates hyperoxia-induced kidney injury in newborn rats
Published in Renal Failure, 2019
Hsiu-Chu Chou, Chung-Ming Chen
The mammalian kidney develops in three successive phases after embryogenesis: the pronephros, mesonephros, and metanephros phases. Nephrogenesis is complete by the 36th week of gestation in humans. In rodents, which have short gestation periods, the nephrogenesis is incomplete at birth and during the first postnatal 10 d [24]. Many preterm infants need high concentration of oxygen to treat respiratory distress at birth. Thus, newborn rats offer a useful model for studies of kidney development. In this study, we found rats reared in hyperoxia and treated with NS or cathelicidin exhibited significantly lower body weights on postnatal day 7 than did the RA-reared rats treated with NS or cathelicidin. The effects of cathelicidin administration on body weights have not been reported. Our study found that rats reared in hyperoxia exhibited respiratory distress, which may inhibit sucking mother's milk and reduced body weights.
Immunohistochemical Panels to Evaluate Important Immunophenotypes of Human Mesonephros
Published in Fetal and Pediatric Pathology, 2023
Ping L. Zhang, Jacqueline K. Macknis
By the 8th week, the glomerular structures of mesonephros showed opened glomerular capillary loops supported by PAS-positive GBM and GATA3 positive mesangial-like cells. The proximal tubules of the 8th week mesonephros appeared to possess excretory function. KIM-1 is a phagocytoic receptor involved in endocytosis of injured tubular debris and has been used specifically to detect proximal tubular injury (characterized by dilated and flattened proximal tubules) [29,33,40,41]. Our previous study revealed that approximately 77% of metanephros and fetal kidneys had acute tubular injury identified by positive KIM-1 staining, despite various degrees of autolysis in some cases [42]. The proximal tubules of several mesonephros, before the 7th week and at 10th week, stained negatively for KIM-1, implying an inactive status of KIM-1 without significant stress. The positive KIM-1 staining in the proximal tubules of the 8thweek mesonephros suggests that mesonephros can have a proximal tubular response to injury. The 8th week mesonephros demonstrated PAS-positive brush borders, indicating that the mesonephros had a capacity for potential reabsorption. Together, these findings are highly suggestive of transitional glomerular filtration and tubular reabsorption in the 8th week mesonephros. The 8th week may represent a peak period for mesonephros to demonstrate transitional renal function, as the 7th week mesonephros did not show impressive PAS staining along the proximal tubules and by the 10th week the mesonephros already revealed partial differentiation into gonad associated components. It is not known why there is a need for the transitional renal function of human mesonephros. We speculate two possibilities. Mesonephros may intend to show a model as to how to handle glomerular filtration and reabsorption as an induction for the development of metanephros. The other possibility is that an embryo, around 8th week of gestation, may need temporal assistance from mesonephros to handle the intravascular fluid balance and eliminate metabolic wastes via its capacity for glomerular filtration and tubular reabsorption.