title: [Ultrastructural aspects in the development of the human nephron--electron microscopy study].
abstract: We have looked for electron microscopy aspects tissue fragments of human nephrons harvested from fetuses of 7,5-19 weeks to show ultrastructure aspects of the nephron during development.
  
  
  METHODS
  We have used 9 fragments from human embryos; Four cases were aged of 7,5, 8, 12 and 17 weeks. The other 5 cases were between 18 and 19 weeks. Tissue fragments were fixed in glutaraldehyde at 4 degrees C and processed by the classic technique.
  
  
  RESULTS
  The electron microscopy study shows the evolutive steps of the human nephron (stages I-IV), stages met for the 12-19 weeks embryo. For the cases under this age the meta-nephrogenic blastema was dominant. In the IVth development stage, the cells in the proximal tubule show a higher development degree than the distal segments.
  
  
  CONCLUSIONS
  These observations indicate that during early development the proximal segment is better developed and probably more functional than the distal segments.
authors.affiliation: Universitatea de Medicină şi Farmacie Gr.T. Popa Iaşi, Facultatea de Medicină, Disciplina de Biologie Celulară şi Moleculară.
authors.forename: T
authors.initials: T
authors.lastname: Petreuş
authors.forename: Anca
authors.initials: A
authors.lastname: Indrei
authors.forename: Carmen Elena
authors.initials: CE
authors.lastname: Cotrutz
authors.forename: C
authors.initials: C
authors.lastname: Moşoiu
authors.forename: C
authors.initials: C
authors.lastname: Cotrutz
mesh_terms: D047109:Fetal Development; D005333:Fetus; D005865:Gestational Age; D006801:Humans; D007686:Kidney Tubules, Distal / Q000196:embryology / Q000648:ultrastructure; D007687:Kidney Tubules, Proximal / Q000196:embryology / Q000648:ultrastructure; D008854:Microscopy, Electron; D009399:Nephrons / Q000196:embryology* / Q000648:ultrastructure*