Embryonic Kidney Tissue Research Articles

MO024THE ROLE AND MECHANISM OF DECOY RECEPTOR DCR2 IN EMBRYONIC KIDNEY DEVELOPMENT

Abstract Background and Aims Decoy receptor 2 (DcR2), a transmembrane receptor of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), has been regarded as a hallmark of cell senescence. This study aimed to explore the role and the potential mechanism of DcR2 in the embryonic kidney development. Method The 12.5d, 16.5d, 20.5d embryonic kidney and mature renal tissue (8w) form WT and DcR2-KO mice were obtained. The ureteric buds, S-shaped bodies, renal vesicles were observed by periodic Acid-Schiff staining. The expression of DcR2 were detected by IHC. The co-expression of DcR2 and proximal tubular markers (AQP-1, villin), distal tubular markers (AQP-2), senescent markers (P16, LaminB1), proliferation markers (Ki-67, PCNA, Edu) were analyzed by confocal. Results In WT kidneys, DcR2 were specifically expressed in the tubules and the percentage of DcR2 expression were higher than mature renal tissue. In addition, the expression of tubular DcR2 were significantly decreased in DcR2-KO kidney than WT. The number of ureteric buds, S-shaped bodies, renal vesicles were decreased in DcR2-KO kidney than WT. And the cortex of DcR2-KO kidney were thinner and medullar were enlarger than WT. DcR2 were co-expressed with proximal tubular markers AQP-1 and villin, but not with distal tubular markers AQP-2. Furthermore, DcR2 were co-expressed with senescent markers P16 and LaminB1, but not with proliferation markers Ki-67, PCNA, Edu. Conclusion DcR2 is specifically expressed in proximal tubular cells in embryonic kidney, and DcR2 is involved in early renal development. The potential mechanism is related to cell senescence participating in tissue remodeling and inhibiting cell proliferation.

CT in the prize in charge of wilms 'tumor (monocentric study of 13 cases)

Nephroblastoma or Wilms tumor is a malignant tumor that develops at the expense of embryonic kidney tissue. It is the most common kidney tumor in children (> 90%); it represents around 5% to 14% of all childhood cancers. The aim of our work is to recall the contribution of imaging, in particular CT, in the management of this renal tumor. This is a retrospective, single-center study of 136 cases of Wilms tumors diagnosed in our clinic over a 2-year period. The mean age of the patients was 04 years with an extreme of (3 months -12 years) with a female prevalence (8 girls for 5 boys). Abdominal mass dominated in our study in clinical information. Histological confirmation was found in 12 cases, the only non-conforming case was lost to follow-up.

The implication of mitochondrial dysfunction and mitochondrial oxidative damage in di (2-ethylhexyl) phthalate induced nephrotoxicity in both in vivo and in vitro models

Di-(2-ethylhexyl) phthalate (DEHP) and its main metabolite, monoethylhexyl phthalic acid (MEHP), are a serious threat to human and animals’ health in the current century. However, their exact mechanism to induce nephrotoxicity is not clear. In the current study, we addressed toxic effects of MEHP and DEHP on embryonic human kidney cells (HEK-293 cell line) and kidney tissue of rats, respectively. In the HEK-293, MTT assay and oxidative stress parameters were measured after treatment with different concentrations of MEHP. For in vivo study, rats were treated with different doses of DEHP (50, 100, 200, 400 mg/kg) via gavage administration for 45 days. The renal function biomarkers (BUN and creatinine) were determined in serum of rats. Mitochondrial toxic parameters including MTT, mitochondrial membrane potential (MMP), mitochondrial swelling, and also oxidative stress parameters were measured in isolated kidney mitochondria. Histopathological effects of DEHP were also evaluated in rats’ kidneys. We demonstrated that MEHP induced oxidative stress and cytotoxicity in HEK-293 cells in a concentration dependent manner. The administration of DEHP led to histopathological changes in kidney tissue, which concurred with BUN and creatinine alternations in serum of rats. The results of present study showed a significant mitochondrial dysfunction and oxidative stress confirmed by enhancement of mitochondrial swelling, mitochondrial reactive oxygen species (ROS) and malondialdehyde (MDA), and reduction of MMP and mitochondrial glutathione (GSH). Taken together, this study showed that DEHP/MEHP resulted in mitochondrial dysfunction and oxidative damage, which suggest a vital role of mitochondria in DEHP/MEHP-induced nephrotoxicity.

Sonic hedgehog protein regulates fibroblast growth factor 8 expression in metanephric explant culture from BALB/c mice: Possible mechanisms associated with renal morphogenesis.

The sonic hedgehog (SHH) morphogen regulates cell differentiation and controls a number of genes during renal morphogenesis. To date, the effects of SHH on fibroblast growth factors (Fgfs) in embryonic kidney development remain unclear. In the present study, explants of BALB/c mouse embryonic kidney tissues were used to investigate the role of exogenous SHH on Fgf8 and Fgf10 expression levels ex vivo. Ureteric bud branches and epithelial metanephric derivatives were used to determine the renal morphogenesis with Dolichos biflorus agglutinin or hematoxylineosin staining. mRNA expression levels were determined using reverse transcription-quantitative polymerase chain reaction, while the protein expression levels were examined using immunohistochemistry and western blot analysis. During the initial stages of metanephric development, low levels of SHH, Fgf8, and Fgf10 expression were observed, which were found to increase significantly during more advanced stages of metanephric development. In addition, exogenous SHH protein treatment increased the number of ureteric bud branches and enhanced the formation of nephrons. Exogenous SHH reduced the Fgf8 mRNA and protein expression levels, whereas cyclopamine (an SHH-smoothened receptor inhibitor) interfered with SHH-mediated downregulation of Fgf8 expression. By contrast, exogenous SHH protein was not found to modulate Fgf10 mRNA and protein expression levels. In conclusion, these results indicate that the modulatory effects of SHH on BALB/c mouse metanephric explant cultures may involve the regulation of Fgf8 expression but not Fgf10 expression, which provides evidence for the functional role of Fgf proteins in renal morphogenesis.

3D printing of HEK 293FT cell-laden hydrogel into macroporous constructs with high cell viability and normal biological functions

3D printing has evolved into a versatile technology for fabricating tissue-engineered constructs with spatially controlled cells and biomaterial distribution to allow biomimicking of in vivo tissues. In this paper, we reported a novel study of 3D printing of cell lines derived from human embryonic kidney tissue into a macroporous tissue-like construct. Nozzle temperature, chamber temperature and the composition of the matrix material were studied to achieve high cell viability (>90%) after 3D printing and construct formation. Long-term construct stability with a clear grid structure up to 30 days was observed. Cells continued to grow as cellular spheroids with strong cell–cell interactions. Two transfected cell lines of HEK 293FT were also 3D printed and showed normal biological functions, i.e. protein synthesis and gene activation in responding to small molecule stimulus. With further refinement, this 3D cell printing technology may lead to a practical fabrication of functional embryonic tissues in vitro.

Mutations in ANKS6 Cause a Nephronophthisis-Like Phenotype with ESRD

Nephronophthisis (NPHP) is one of the most common genetic causes of CKD; however, the underlying genetic abnormalities have been established in <50% of patients. We performed genome-wide analysis followed by targeted resequencing in a Turkish consanguineous multiplex family and identified a canonic splice site mutation in ANKS6 associated with an NPHP-like phenotype. Furthermore, we identified four additional ANKS6 variants in a cohort of 56 unrelated patients diagnosed with CKD due to nephronophthisis, chronic GN, interstitial nephritis, or unknown etiology. Immunohistochemistry in human embryonic kidney tissue demonstrated that the expression patterns of ANKS6 change substantially during development. Furthermore, we detected increased levels of both total and active β-catenin in precystic tubuli in Han:SPRD Cy/+ rats. Overall, these data indicate the importance of ANKS6 in human kidney development and suggest a mechanism by which mutations in ANKS6 may contribute to an NPHP-like phenotype in humans.

High resolution 4-dimension imaging of metanephric embryonic kidney morphogenesis

High resolution three-dimensional imaging of fixed embryonic kidney tissues has advanced considerably in the past decade. Here we developed a new process for imaging whole metanephric organ culture at cell resolution in three dimensions over time. This technique combines the use of the newly available generation of infrared optimized long working distance high numerical aperture objectives and multiphoton fluorescence microscopy with a new system for vital staining of metanephric organ cultures with bodipy ceramide. This allows all cells in the organ culture to be visualized over time, enabling detailed observation of tissue morphogenesis. Thus, our method offers a powerful new approach for visualizing and understanding early events in renal development and for extending observations made in genetically manipulated models.

Proteomic analysis of chicken embryonic trachea and kidney tissues after infection in ovo by avian infectious bronchitis coronavirus

BackgroundAvian infectious bronchitis (IB) is one of the most serious diseases of economic importance in chickens; it is caused by the avian infectious coronavirus (IBV). Information remains limited about the comparative protein expression profiles of chicken embryonic tissues in response to IBV infection in ovo. In this study, we analyzed the changes of protein expression in trachea and kidney tissues from chicken embryos, following IBV infection in ovo, using two-dimensional gel electrophoresis (2-DE) coupled with matrix-assisted laser desorption/ionization time-of-flight tandem mass spectrometry (MALDI-TOF-TOF MS).Results17 differentially expressed proteins from tracheal tissues and 19 differentially expressed proteins from kidney tissues were identified. These proteins mostly related to the cytoskeleton, binding of calcium ions, the stress response, anti-oxidative, and macromolecular metabolism. Some of these altered proteins were confirmed further at the mRNA level using real-time RT-PCR. Moreover, western blotting analysis further confirmed the changes of annexin A5 and HSPB1 during IBV infection.ConclusionsTo the best of our knowledge, we have performed the first analysis of the proteomic changes in chicken embryonic trachea and kidney tissues during IBV infection in ovo. The data obtained should facilitate a better understanding of the pathogenesis of IBV infection.

Genomic characterization of Wilms' tumor suppressor 1 targets in nephron progenitor cells during kidney development

The Wilms' tumor suppressor 1 (WT1) gene encodes a DNA- and RNA-binding protein that plays an essential role in nephron progenitor differentiation during renal development. To identify WT1 target genes that might regulate nephron progenitor differentiation in vivo, we performed chromatin immunoprecipitation (ChIP) coupled to mouse promoter microarray (ChIP-chip) using chromatin prepared from embryonic mouse kidney tissue. We identified 1663 genes bound by WT1, 86% of which contain a previously identified, conserved, high-affinity WT1 binding site. To investigate functional interactions between WT1 and candidate target genes in nephron progenitors, we used a novel, modified WT1 morpholino loss-of-function model in embryonic mouse kidney explants to knock down WT1 expression in nephron progenitors ex vivo. Low doses of WT1 morpholino resulted in reduced WT1 target gene expression specifically in nephron progenitors, whereas high doses of WT1 morpholino arrested kidney explant development and were associated with increased nephron progenitor cell apoptosis, reminiscent of the phenotype observed in Wt1(-/-) embryos. Collectively, our results provide a comprehensive description of endogenous WT1 target genes in nephron progenitor cells in vivo, as well as insights into the transcriptional signaling networks controlled by WT1 that might direct nephron progenitor fate during renal development.

ROCK inhibition facilitates tissue reconstitution from embryonic kidney cell suspensions

Explanted embryonic kidney tissues, when placed in organ culture, recapitulate key aspects of nephron formation. Yet attempts to dissociate these tissues into single cells to make them more accessible for genetic manipulation and tissue recombination have been disappointing. Now it is reported that inhibitors of Rho-associated kinase (ROCK) facilitate tissue reconstitution and nephron differentiation from single-cell suspensions of the embryonic kidney. This finding illustrates an unexpected potential for self-organization in these cells and introduces a window of single-cell accessibility to the organ culture system.

PAX2 Activates WNT4 Expression during Mammalian Kidney Development

The transcription factor PAX2 is expressed during normal kidney development and is thought to influence outgrowth and branching of the ureteric bud. Mice with homozygous null Pax2 mutations have developmental defects of the midbrain-hindbrain region, optic nerve, and ear and are anephric. During nephrogenesis, PAX2 is also expressed by mesenchymal cells as they cluster and reorganize to form proximal elements of each nephron, but the function of PAX2 in these cells is unknown. In this study we hypothesized that PAX2 activates expression of WNT4, a secreted glycoprotein known to be critical for successful nephrogenesis. PAX2 protein was identified in distal portions of the "S-shaped" body, and the protein persists in the emerging proximal tubules of murine fetal kidney. PAX2 activated WNT4 promoter activity 5-fold in co-transfection assays with JTC12 cells derived from the proximal tubule. Inspection of the 5'-flanking sequence of the human WNT4 gene identified three novel PAX2 recognition motifs; each exhibited specific PAX2 protein binding in electromobility shift assays. Two motifs were contained within a completely duplicated 0.66-kb cassette. Transfection of JTC12 cells with a PAX2 expression vector was associated with a 7-fold increase in endogenous WNT4 mRNA. In contrast, Wnt4 mRNA was decreased by 60% in mesenchymal cell condensates of fetal kidney from mice with a heterozygous Pax2 mutation. We speculated that a key function of PAX2 is to activate WNT4 gene expression in metanephric mesenchymal cells as they differentiate to form elements of the renal tubules.

GLI3-dependent transcriptional repression ofGli1, Gli2and kidney patterning genes disrupts renal morphogenesis

Truncating mutations in Gli3, an intracellular effector in the SHH-SMO-GLI signaling pathway, cause renal aplasia/dysplasia in humans and mice. Yet, the pathogenic mechanisms are undefined. Here, we report the effect of decreased SHH-SMO signaling on renal morphogenesis, the expression of SHH target genes and GLI binding to Shh target genes. Shh deficiency or cyclopamine-mediated SMO inhibition disrupted renal organogenesis, decreased expression of GLI1 and GLI2 proteins, but increased expression of GLI3 repressor relative to GLI3 activator. Shh deficiency decreased expression of kidney patterning genes (Pax2 and Sall1) and cell cycle regulators (cyclin D1 and MYCN). Elimination of Gli3 in Shh(-/-) mice rescued kidney malformation and restored expression of Pax2, Sall1, cyclin D1, MYCN, Gli1 and Gli2. To define mechanisms by which SHH-SMO signaling controls gene expression, we determined the binding of GLI proteins to 5' flanking regions containing GLI consensus binding sequences in Shh target genes using chromatin immunoprecipitation. In normal embryonic kidney tissue, GLI1 and/or GLI2 were bound to each target gene. By contrast, treatment of embryonic kidney explants with cyclopamine decreased GLI1 and/or GLI2 binding, and induced binding of GLI3. However, cyclopamine failed to decrease Gli1 and Gli2 expression and branching morphogenesis in Gli3-deficient embryonic kidney tissue. Together, these results demonstrate that SHH-SMO signaling controls renal morphogenesis via transcriptional control of Gli, renal patterning and cell cycle regulator genes in a manner that is opposed by GLI3.

P38MAPK Acts in the BMP7-dependent Stimulatory Pathway during Epithelial Cell Morphogenesis and Is Regulated by Smad1

Bone morphogenetic protein (BMP)-7 exerts dose-dependent stimulatory and inhibitory effects during renal branching morphogenesis. Previously, we identified an inhibitory role for activin-like kinase receptors and Smad1 in BMP-dependent inhibition (Piscione, T. D., Phan, T., and Rosenblum, N. D. (2001) Am. J. Physiol. 280, F19-F33). Here we demonstrate a novel role for p38 mitogen-activated kinase (p38(MAPK)) in BMP7-dependent stimulatory signaling. Stimulatory doses (0.25 nm) of BMP7 increased p38(MAPK) activity and stimulated phosphorylation of endogenous activating transcription factor 2 (ATF2) in a p38(MAPK)-dependent manner in murine inner medullary collecting duct (mIMCD-3) cells. In contrast, high doses (10 nm) of BMP7 inhibited p38(MAPK) activity and phosphorylation of endogenous ATF2. Treatment with BMP7 exerted no significant effect on the levels of the phosphorylated forms of endogenous SAPK/JNK or p44 and p42 (ERK1 and ERK2) protein kinases. To investigate the functional importance of p38(MAPK) signaling, we showed that SB203580, a p38(MAPK) inhibitor, blocked the stimulatory effect of BMP7 on mIMCD-3 cell morphogenesis but had no effect on BMP7-dependent inhibition in a three-dimensional culture model. To identify mechanisms by which BMP7-dependent inhibitory signaling suppresses p38(MAPK) activity, we measured p38(MAPK) activity in ligand independent mIMCD-3 models of enhanced and suppressed Smad signaling. Basal activity of p38(MAPK) was decreased in mIMCD-3 cells and in embryonic kidney tissue expressing a constitutively active activin-like kinase receptor, but was increased in mIMCD-3 cells stably expressing a dominant negative form of Smad1. We conclude that BMP7 stimulates renal epithelial cell morphogenesis via p38(MAPK) and that p38(MAPK) activity is negatively regulated by Smad1.

Identification and Characterization of Galectin-9, a Novel β-Galactoside-binding Mammalian Lectin

A 36-kDa beta-galactoside mammalian lectin protein, designated as galectin-9, was isolated from mouse embryonic kidney by using a degenerate primer polymerase chain reaction and cloning strategy. Its deduced amino acid sequence had the characteristic conserved sequence motif of galectins. Endogenous galectin-9, extracted from liver and thymus, as well as recombinant galectin-9 exhibited specific binding activity for the lactosyl group. It had two distinct N- and C-terminal carbohydrate-binding domains connected by a link peptide, with no homology to any other protein. Galectin-9 had an alternate splicing isoform, exclusively expressed in the small intestine with a 31-amino acid insertion between the N-terminal domain and link peptide. Sequence homology analysis revealed that the C-terminal carbohydrate-binding domain of mouse galectin-9 had extensive similarity to that of monomeric rat galectin-5. The presence of galectin-5 in the mouse could not be demonstrated by polymerase chain reaction or by Northern or Southern blot genomic DNA analyses. Sequence comparison of rat galectin-5 and rat galectin-9 cDNA did not reveal identical nucleotide sequences in the overlapping C-terminal carbohydrate-binding domain, indicating that galectin-9 is not an alternative splicing isoform of galectin-5. However, galectin-9 had a sequence identical with that of its intestinal isoform in the overlapping regions in both species. Southern blot genomic DNA analyses, using the galectin-9 specific probe derived from the N-terminal carbohydrate-binding domain, indicated the presence of a novel gene encoding galectin-9 in both mice and rats. In contrast to galectin-5, which is mainly expressed in erythrocytes, galectin-9 was found to be widely distributed, i.e. in liver, small intestine, thymus > kidney, spleen, lung, cardiac and skeletal muscle > reticulocyte, brain. Collectively, these data indicate that galectin-9 is a new member of the galectin gene family and has a unique intestinal isoform.

Tenascin is an important component of the glomerular extracellular matrix in normal and pathologic conditions

Tenascin (TN), a large oligomeric glycoprotein, is a recently described component of the extracellular matrix (ECM). Previous reports focusing largely on the role of TN in nephrogenesis have documented the strong expression of TN in embryonic kidney tissue and implied an important role for TN in nephrogenesis. However, the expression of TN in normal and pathologic kidneys in adults has not been systematically evaluated. In this study immunohistochemical staining for TN was applied to 184 renal specimens diagnosed as: normal kidney (23 cases); minimal change disease and its variants (8); mesangial proliferative glomerulonephritis (GN) including IgA nephropathy and mesangial proliferative lupus nephritis (9); endocapillary proliferative GN including membranoproliferative GN, lupus nephritis, and post-infectious GN (25); crescentic GN (11); membranous GN (19); focal segmental sclerosis (15); thrombotic microangiopathy (8); amyloidosis (5); diabetic nephropathy (9); primary tubulointerstitial nephritis (14); transplant rejection (14); and ischemia (24). It was found that: (a) there was unequivocal global diffuse staining limited to the mesangium in normal kidney; (b) regardless of the etiologies and the morphologic types of glomerular disease, whenever there was expansion of the ECM, whether in the mesangial, endocapillary, or extracapillary spaces, there was a concomitant and proportional in situ increase in the TN staining; (c) globally sclerotic glomeruli, regardless of causes, showed diffuse, strong staining, especially in the subcapsular fibrous deposition seen in ischemic sclerosis; (d) non-sclerotic glomeruli showing early ischemic change uniformly displayed a marked decrease or complete loss of staining; (e) in cases of thrombotic microangiopathy, there was segmental or global staining of the capillary wall, probably corresponding to the enlarged lamina rara interna; (f) all nodular lesions in diabetic glomerulosclerosis showed strong staining, but in several of them this staining was much more pronounced in the periphery than in the center of the lesion. Our study proves that TN is probably a component of the normal mesangial matrix, that TN is an ubiquitous component of the expanded glomerular ECM in pathologic conditions regardless of morphologic subtypes, and that further studies on the cell types and mechanisms responsible for TN synthesis may provide a new venue for the understanding of the process of glomerular sclerosis.

Retrovirus‐like particles in embryonic kidney tissue of the platyfish, Xiphophorus maculatus

Ultrastructural studies were performed on embryos of an inbred strain (163A) of the platyfish Xiphophorus maculatus, and a pooled stock of the Rio Sarabia strain of the swordtail, X. helleri. Viral-like particles were found in the kidney tissue of platyfish embryos. Exposure of pregnant platyfish to 5-bromodeoxyuridine during the time of differentiation of embryonic melanocytes enhanced the production of viral-like particles in platyfish embryos. Viral-like particles were not found in untreated or drug-treated swordtail embryos. The morphology of these particles corresponds to type C retroviruses.

Transplacental effect of methylcobalamin on growth of mouse embryonic kidney tissue in organ culture

This paper gives the results of a study of the transplacental action of methylcobalamin (MC) on growth of embryonic tissues during organ culture. An organ culture of embryonic mouse kidney tissue, sensitive to the transplacental action of biologically active substances, including vitamins and hormones, and also of chemical carcinogens, was used as the experimental model. /sup 3/H-thymidine was added to the nutrient medium before fixation of the explants. The stimulating effect of MC on growth of mouse kidney tissue in the prenatal period as revealed in this investigation, is said by the authors to be an important mechanism modifying the transplacental action of chemical carcinogens.

Purification and characterization of the principal inhibitor of calcium oxalate monohydrate crystal growth in human urine.

Using an assay of the rate of crystal growth of calcium [14C]oxalate monohydrate, we ascertained that the factor responsible for more than 90% of the crystal growth inhibition in human urine is a nondialyzable macromolecule. We have purified this factor using DEAE-cellulose chromatography, followed by Bio-Gel P-10 column chromatography with 50% formamide as the eluent, and finally by gel permeation chromatography. About 5 mg of the inhibitor was obtained from normal 24-h adult urine, with 16% recovery of the original inhibitory activity. The inhibitor isolated was found to be a highly acidic glycoprotein with Mr = 1.4 X 10(4). It is rich in acidic amino acids, including gamma-carboxyglutamic acid, and contains few aromatic and basic amino acids. Two or three phosphate groups are covalently linked to the inhibitor. In the presence of the inhibitor, the kinetics of calcium oxalate monohydrate crystal growth inhibitor showed that the macromolecule binds to the crystal surface according to a Langmuir adsorption isotherm with a dissociation constant, Kd = 5.3 X 10(-7) M. The inhibitor readily formed an insoluble monolayer at the air-water interface and showed an unusually high surface stability with a collapse pressure of 41.5 dynes/cm. The urinary inhibitor closely resembled in all properties the calcium oxalate monohydrate crystal growth inhibitor that we had isolated from human embryonic kidney tissue culture medium (Nakagawa, Y., Margolis, H. C., Yokoyama, S., Kézdy, F. J., Kaiser, E. T., and Coe, F. L. (1981) J. Biol. Chem. 256, 3936-3944).

The cytogenetic, proliferative and viability effects of four bacteriophages on human lymphocytes.

Certain bacteriophages have been found in live virus vaccines, while a few others have been associated with disease states. Some of these phages have produced abnormal growth of eukaryotic tissue cultures. For this reason bacteriophages phiX-174, MS2, T2 and an isolate from live virus vaccines, phiV-1, were incubated with human cell cultures for examination of chromosomal effects, cell proliferation and viability. Mitogen-stimulated lymphocytes and human embryonic kidney tissue cultures showed no increase in chromosomal abnormalities for high doses of phage-infected versus control cultures. Tritiated-thymidine uptake, correlated with mitotic indices for phage-treated lymphocyte cultures, indicated a reduction in cell division, while 51-chromium release studies showed no cell death occurring in these cultures. This suggested that inhibition of DNA synthesis was occurring in some cells. The presence of phage in the supernate of cells that were exposed to phage suggested the possibility of phage attachment to the plasma membranes of lymphocytes, which may in turn affect the suppression of DNA synthesis.

The effect produced by some carcinogenic nitrosocompounds on organ cultures from human embryonic lung and kidney tissues.

Previous works using organ cultures of lung and kidney tissues of mouse, rat and hamster embryos exposed to transplacental action of some carcinogens showed premalignant growth. This paper presents the results of organ culture of human embryonic lung and kidney tissues. Direct action of some carcinogenic nitrosocompounds (N-nitrosomethylurea, dimethylnitrosamine and orthoaminoazotoluene) resulted in higher survival of the treated organ cultures and induced epithelial hyperplasia. The changes depended directly upon the dose of carcinogen employed.