Relative studies between hair index, hair area, and medullary index with age and sex in Thai scalp hair.

Human scalp hair is one of the most common trace materials found at violent crime scenes. Accordingly, scalp hair is critical evidential material in forensic investigations for identifying relations and persons, which could result in solving cases. Knowledge about micro-morphological variations of scalp hair in the Thai population, however, is scarce, and information on age changes and sex differences with respect to these traits is limited. The present study was thus undertaken to explore three micro-morphological parameters of Thai scalp hair-hair index (HI), hair area (HA), medullary index (MI)-relative to age and sex differences. Scalp hair samples were collected from 340 unrelated Thai cadavers (170 male, 170 female) of all ages, which were divided into seventeen age groups, 5-year-old interval per group beginning with 0-5years and ending up with ≥80 years. Approximately 30 hair strands at the posterior vertex region of the scalp were cut with scissors as close to the scalp as possible. The hair samples were subsequently used to make permanent slides, and the mounted hairs were examined for microscopic cross-sectional characteristics. The authors found that the HI and MI were similar in the male and female cadavers and did not significantly differ (p>0.05) according to age. In contrast, the HA was significantly different between the male and female cadavers at 50-69years of age (p<0.05). There were other differences according to age as well. That is, the HA increased abruptly during their early twenties and then decreased gradually until ≥80 years of age. Thus, Thai scalp hair shows some age and sex variations that are reflected in the HA and might be useful for forensic, medical, and anthropological investigations.

The Stability of Prostate-Specific Antigen in Semen Under Various Temperatures.

Prostate-specific antigen (PSA) is most commonly used for identifying semen, especially in the absence of sperm. However, PSA concentration varies according to storage temperature and duration, and little is known about its stability in semen. This study was therefore aimed to determine the stability under five different temperatures: -80, -20, 4, 25, and 37°C; and nine different durations: 1, 2, 3, 5, 7, 14, 30, 90, and 180 days. All samples were stored at -80°C after being secreted from the volunteers' body until analyzed. Results showed that the PSA concentration declined significantly over time under all temperatures studied except -80°C. At -20 and 4°C, PSA was still detectable on Day 180 with 50% and 70% decrease from its original concentration, respectively. At 25 and 37°C, PSA was detected up to Day 7 and 3, respectively. This information might assist forensic scientists understand more about PSA nature and integrate it into their works.

Sensitive detection of Pneumocystis jirovecii DNA in gastric wash using nested polymerase chain reaction.

One hundred and five samples of gastric washes were obtained from 52 pediatric patients. Eleven of the 105 samples (10%) gave positive results using immunofluorescence antibody test (IFA) for Pneumocystis jirovecii. Single-step polymerase chain reaction (PCR) produced 13% (14 samples), whereas detection by nested PCR was increased to 65 samples (62%). Moderate agreement (kappa = 0.5) was found between test results of IFA and single-step PCR, but no agreement was found between the results of IFA and nested PCR (kappa = 0.1).