The effect of tea catechins on the forensic identification of urine: Urine camouflage to evade drug tests.

BACKGROUND: We encountered a urine sample suspected of being mixed with tea, submitted by a suspect attempting to camouflage illegal drugs. Although urine should turn reddish-pink during a urea test with p-Dimethylaminocinnamaldehyde (DAC), this suspect's sample exhibited a blue coloration when tested with DAC. AIM: Our aim was to examine the influence and mechanism of green tea on various urine identification tests. RESULTS: Our examination revealed that DAC forms a compound with the urea in urine, resulting in a reddish pink coloration with a molecular weight of 217. However, it has been reported that DAC binds to polyphenols such as catechin. In the case of catechin, DAC binds to the C8 position, forming a compound that exhibits the highest absorption at 640 nm and appears blue. we investigated the effect of urine from volunteers who had consumed a large amount of catechin on the urea test with DAC. Additionally, we carried out quantitative analysis of catechin in urine by LC-MS/MS after enzymatic treatment with ß-glucuronidase. The concentration of urinary excreted catechin reached its peak approximately 3 to 4 h after ingestion. During the DAC test, urine samples collected 3 to 4 h after catechin ingestion displayed a bluish pink color, but not the blue color observed in the original suspect sample. CONCLUSION: This study investigated the impact of catechin on urine tests, revealing that a blue color in the DAC test indicates a high likelihood of camouflage by the suspect.

Kinship analysis using DNA typing from five skeletal remains with an unusual postmortem course.

The skeletal remains of five individuals with an unusual postmortem course were discovered in a house. According to the explanation of the putative bereaved family, the postmortem interval of the five remains was between five and 20 years. They also explained to the police that they and the dead family members believed that the dead can be resurrected, and they had kept the bodies indoors, so the bodies had followed an unusual postmortem course. The five dead were identified by kinship analysis using DNA typing. For DNA extraction, we used the DNA extraction method with ultrafiltration and a silica-based DNA extraction kit. As a result, complete amplification STR profiles were obtained from DNA from bone samples of all five skeletons and their identity was proven by kinship testing.

Dual examinations for identification of urine as being of human origin and for DNA-typing from small stains of human urine.

Concurrent methods for identification of urine as being of human origin, and for DNA-typing from small stains of human urine were examined. A urine stain was extracted with phosphate-buffered saline (PBS), and the extract was filtered using a Centricon-100 device. The filtrate was subjected to electrospray ionization liquid chromatography-mass spectrometry (ESI-LC-MS) for identification of human urine and a DNA-typing sample was obtained by dialfiltration of the residue using a DNA purification kit. After the purified residue was treated with an AmpflSTR Profiler PCR amplification kit, the DNA-types were analyzed by capillary electrophoresis using a Genetic Analyzer. It was possible to identify a urine stain as being of human origin, and complete DNA profiles could be successfully obtained from a urine stain which had been created by 50 microL of female urine. Serial analyses of urine stains found at a crime scene provide effective information for forensic investigation. This method is recommended for stain identification and for DNA-typing from a urine stain.

Successful DNA typing of urine stains using a DNA purification kit following dialfiltration.

To evaluate the utility of DNA polymorphism typing of urine stains in forensic investigations, the amplifiable amount of DNA was estimated in 20 urine specimens obtained from 10 male and 10 female volunteers using a DNA purification kit following dialfiltration. DNA obtained from both urine and urine stains was amplified with the AmpflSTR Profiler PCR Amplification Kit, and was analyzed by capillary electrophoresis using the Genetic Analyzer. The amount of male and female urine necessary for obtaining a complete DNA profile was 0.2 mL and 0.08 mL, respectively. When 0.2 mL of male urine were used to create urine stains, complete DNA profiles could be obtained from just some of the stains. However, when only 0.1 mL of female urine was used, complete profiles could be successfully obtained from all of the stains. DNA on bleached cotton remained amplifiable for 3-6 weeks. This method using a DNA purification kit following dialfiltration can be recommended for the genotyping of urine stains.