title: [Expression and significance of respiratory chain enzyme of cells in urine sediment in MELAS syndrome].
abstract: OBJECTIVE
  To explore the expression and significance of respiratory chain enzyme of cells in urine sediment in mitochondrial encephalopathy myopathy, lactic acidosis and stroke-like episodes (MELAS) syndrome.
  
  
  METHODS
  Through enzyme histochemistry, the authors analyzed the changes of respiratory chain enzyme in urine sediment in 20 MELAS patients due to mitochondrial A3243G mutation (MELAS group) and 20 health peoples (control group). And the impact on the expression of protein encoded by nuclear DNA (A21347) and mitochondrial DNA (A6404) was detected by immunochemistry. Image pro Plus 6.0 software was used for analysis of absorbance (A) of staining images as staining intensity. The data were expressed as M (Q1, Q3) and analyzed through statistical software.
  
  
  RESULTS
  The staining intensity of complexes Iin the MELAS group was lower than that in the control group (0.06(0.01, 0.12) vs 0.12(0.01, 0.62), P = 0.010). The intergroup staining intensity of complex II showed no marked difference. Increased density of blue particle and cytoplasmic gathering was found in 13 cased (65%) of the MELAS group under light microscope. The staining intensity of complexes IV was expressed at a low level in the MELAS group (0.14(0.03, 0.32) vs 0.23(0.06, 0.43), P = 0.038). The expression of protein encoded by nuclear DNA (A21347) was lower than that in the control group (0.05(0.02, 0.45) vs 0.17(0.03, 0.70), P = 0.000). The expression of protein encoded by mitochondrial DNA (A6404) was also lower than that in the control group (0.03(0.01, 0.07) vs 0.15 (0.09, 0.23), P = 0.000).
  
  
  CONCLUSIONS
  Abnormal change of respiratory chain enzyme in urine sediment in MELAS due to mitochondrial A3243G mutation and a low expression of proteins encoded by two kinds of DNA in complexes IV can help to confirm the genetic diagnosis of mitochondrial encephalomyopathies so that different subtypes may be classified and its pathogenesis elucidated.
authors.affiliation: Department of Pathology, Beijing Tongren Hospital, Capital Medical University, Beijing 100730, China.
authors.forename: Hai-rong
authors.initials: HR
authors.lastname: Wu
authors.forename: Yi-nan
authors.initials: YN
authors.lastname: Ma
authors.forename: Yu
authors.initials: Y
authors.lastname: Qi
authors.forename: Hong-gang
authors.initials: HG
authors.lastname: Liu
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D002467:Cell Nucleus / Q000235:genetics; D002648:Child; D002675:Child, Preschool; D004272:DNA, Mitochondrial / Q000235:genetics; D004579:Electron Transport; D003576:Electron Transport Complex IV / Q000235:genetics / Q000652:urine*; D005260:Female; D006801:Humans; D017241:MELAS Syndrome / Q000201:enzymology* / Q000378:metabolism / Q000652:urine; D008297:Male; D008875:Middle Aged; D051336:Mitochondrial Membranes / Q000378:metabolism; D009154:Mutation; D055815:Young Adult
chemical_list: D004272:DNA, Mitochondrial; D003576:Electron Transport Complex IV