Kainic acid - induced neuronal death is associated with DNA damage and unique immediate - early gene

An elongated tubular nipple is provided including upper and lower ends. The interior of the nipple defines a longitudinal bore extending therethrough and the lower and upper ends of the bore are downwardly and upwardly flared, respectively. The upper end portion of the nipple includes an externally threaded diametrically enlarged portion for threaded engagement within the internally threaded upper end of a tubular pumping tee mounted atop a tubing string section and the length of the nipple from the externally threaded diametrically enlarged portion to the lower end thereof is such to enable the nipple, when mounted within a pumping tee, to have its lower end at least closely adjacent the upper end of the tubing section from which the pumping tee is supported. The interior diameter of the nipple bore is of a size to substantially equal the interior diameter of the tubing string section from which the pumping tee is supported and the nipple serves to form an upward extension of the bore of the tubing string section through the pumping tee, whereby the sucker rod sections and scrappers or centralizers on the sucker rod sections may be guided as the sucker rod is being withdrawn from or downwardly inserted into the tubing string.