title: [Effect of urinary trypsin inhibitor on DNA genotyping in urine samples].
abstract: OBJECTIVE
  To study the effect of urinary trypsin inhibitor (UTI) on STR genotyping with urinary samples.
  
  
  METHODS
  Midstream urine samples of 5 male and 5 female volunteers were collected respectively, sub-packaged, added with different concentration of UTI and stored at -80 degrees C. Genomic DNA was extracted from those urinary samples, of which STR profiles were genotyped with IdentifilerTM kit at 8 different time points. Results of genotyping in urinary samples were compared with those of the homogenous blood control samples and the successful rate of genotyping in different group of urinary samples treated with UTI was determined.
  
  
  RESULTS
  Fifteen STR loci included in Identifiler system were all detected in control blood samples and urinary samples stored for 1 day. STR locus loss was observed and all 15 STR loci disappeared in female urinary samples untreated with UTI while those storage periods prolonged to 3 and 9 days, respectively. However, all 15 STR loci could be detected in female urinary samples treated with UTI and stored for as long as 9 days. No STR loci could be detected in male urinary samples preserved without UTI for 7 days while 9 STR loci detected preserved with UTI for 9 days. There was no significant difference among the average detection ratios of STR loci in female urinary samples treated with UTI at concentrations of 0.2, 0.4 or 0.6 microg/mL and stored for 30 days, mean of which was as high as 0.8400 +/- 0.0423, statistically higher than that in male urinary samples (0.1600 +/- 0.0423).
  
  
  CONCLUSIONS
  Detection rate of STR loci in urinary samples preserved with UTI was increased significantly, which results in prolonging the storage periods of urinary samples for personal identification.
authors.affiliation: Shanghai Key Laboratory of Forensic Medicine, Institute of Forensic Science, Ministry of Justice, PR China, Shanghai 200063, China. zsh-daisy@163.com
authors.forename: Su-hua
authors.initials: SH
authors.lastname: Zhang
authors.forename: Shu-min
authors.initials: SM
authors.lastname: Zhao
authors.forename: Cheng-tao
authors.initials: CT
authors.lastname: Li
mesh_terms: D004247:DNA / Q000097:blood / Q000235:genetics* / Q000652:urine; D016172:DNA Fingerprinting / Q000379:methods*; D005260:Female; D053803:Forensic Genetics / Q000379:methods; D056426:Genetic Loci / Q000235:genetics; D005838:Genotype; D006023:Glycoproteins / Q000494:pharmacology*; D006801:Humans; D008297:Male; D018895:Microsatellite Repeats; D016133:Polymerase Chain Reaction; D013048:Specimen Handling / Q000379:methods; D013997:Time Factors; D014361:Trypsin Inhibitors / Q000494:pharmacology*
chemical_list: D006023:Glycoproteins; D014361:Trypsin Inhibitors; D004247:DNA; C028665:urinastatin