α-Globin Messenger Ribonucleic Acid as a Molecular Marker for Determining the Age of Human Blood Spots in Different Temperatures

Background: Analyzing recovered evidence, such as blood which is one of the most encountered types of biological evidence, can provide information to establish the definite time when a crime was committed. This study aims to investigate the time- and temperature-related effects on human bloodstain’s α-globin messenger RNA expression and to estimate the bloodstain’s age using α-globin mRNA. Methods: A total of 22 blood samples were collected from healthy middle-aged volunteers (12 women and 10 men). After preparation, the samples were exposed to temperatures of 4°C, 24°C, and 40°C. Next, the mRNA expression of the α-globin gene was quantified by real-time RT-PCR at different time intervals of 0, 30, 90, and 150 days.Results: The α-globin gene expression showed the highest mean values by 0 day and at 4°C and the lowest mean values by 150 days and at 40°C. Samples from male participants showed higher mean values of α-globin gene expression compared to their female counterparts. A significant negative correlation was detected between α-globin gene expression and time interval. Meanwhile, a regression equation was formulated to estimate the time interval using the α-globin gene concentration.Conclusion: α-Globin mRNA could be a useful marker to estimate the age of human blood spots

Extracting structural features of rat sciatic nerve using polarization-sensitive spectral domain optical coherence tomography

We present spectral domain polarization-sensitive optical coherence tomography (SD PS-OCT) imaging of peripheral nerves. Structural and polarization-sensitive OCT imaging of uninjured rat sciatic nerves was evaluated both qualitatively and quantitatively. OCT and its functional extension, PS-OCT, were used to image sciatic nerve structure with clear delineation of the nerve boundaries to muscle and adipose tissues. A long-known optical effect, bands of Fontana, was also observed. Postprocessing analysis of these images provided significant quantitative information, such as epineurium thickness, estimates of extinction coefficient and birefringence of nerve and muscle tissue, frequency of bands of Fontana at different stretch levels of nerve, and change in average birefringence of nerve under stretched condition. We demonstrate that PS-OCT combined with regular-intensity OCT (compared with OCT alone) allows for a clearer determination of the inner and outer boundaries of the epineurium and distinction of nerve and muscle based on their birefringence pattern. PS-OCT measurements on normal nerves show that the technique is promising for studies on peripheral nerve injury. © 2012 Society of Photo-Optical Instrumentation Engineers (SPIE)