Direct Capture Of Sperm Cells

Several approaches have been taken to directly sample sperm cells from sexual assault cases. One strategy is to physically separate the perpetrator's sperm cells from the victim's epithelial cells. Sperm cells can be collected on magnetic particles or beads that can be coated with antibodies specific for sperm proteins (Marshall 2002). The beads are then washed to remove the female epithelial cells. Finally, the purified sperm are placed into a PCR reaction to produce a DNA profile of the perpetrator. This approach depends on sperm being intact, which is not always the case with old sexual assault evidence.

Another exciting approach to selectively capturing sperm is the use of a clinical procedure known as laser-capture microdissection, which is commonly used to select tumor cells from surrounding tissue on microscope slides. Sperm cells from sexual assault evidence spread on microscope slides can be collected with laser-capture microdissection to perform reliable STR testing (Elliot et al. 2003). When sperm cells are observed in the field of view of the microscope, a tiny laser is activated and a thin plastic film placed over the slide melts at the specific point of laser light contact to capture or embalm the cell of interest. By moving the microscope slide around, dozens of sperm cells are collected onto this thin film that sits directly above the sample. The collection film is then transferred to a tube where DNA from the isolated sperm can be extracted and amplified using the polymerase chain reaction (see Chapter 4).

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Stammering Its Cause and Its Cure

Stammering Its Cause and Its Cure

This book discusses the futility of curing stammering by common means. It traces various attempts at curing stammering in the past and how wasteful these attempt were, until he discovered a simple program to cure it. The book presents the life of Benjamin Nathaniel Bogue and his struggles with the handicap. Bogue devotes a great deal of text to explain the handicap of stammering, its effects on the body and psychology of the sufferer, and its cure.

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