Determination of ²²6Ra, ²²8Ra and ²¹°Pb in NORM products from oil and gas exploration: problems in activity underestimation due to the presence of metals and self-absorption of photons.

Typical calibration of solid environmental samples for the determination of (226)Ra, (228)Ra and (210)Pb entails the use of standard reference materials which have a very similar matrix. However, TENORM samples from the oil and gas exploration contain unusually high amounts of calcium, strontium and barium which can severely attenuate the photons of (210)Pb and (226)Ra with their characteristic 46.1 keV and 186.2 keV gamma-rays, respectively and to some extent (228)Ra with the characteristic gamma-rays of 911.2 keV and 969.0 keV. We used neutron activation analysis to evaluate the content of TENORM for calcium, barium and strontium and then used a software program SELABS to determine the self-absorption. Our results confirm that even in Petrie containers with small dimensions the (210)Pb can be underestimated by almost by a factor of four while (226)Ra can be underestimated by 5%. The (228)Ra activities are virtually unaffected due to the higher energy gamma-rays. However, the implications for TENORM studies that employ large Marinelli containers having sample sizes between 0.25 and 1.0 L may be severely compromised by the presence of high Z elements in elevated concentrations. The usual spectral interferences on (226)Ra, (228)Ra and (210)Pb coming from other radionuclides in the (234)U, (235)U and (238)U decay chains are virtually nonexistent due the very high activity levels of (226)Ra, (228)Ra and (210)Pb in the tens of thousands of Bq/kg.

Gene expression, immunolocalization, and secretion of human defensin-5 in human female reproductive tract.

This study describes the novel localization of the antimicrobial peptide human intestinal defensin-5 (HD-5) in female genital tract epithelia. Using a 3' rapid amplification of cDNA ends (RACE) protocol, HD-5 was cloned from a vaginal epithelial cell RNA preparation, and its identity was confirmed by sequencing. Tissue samples from multiple donors were subsequently screened for HD-5 expression by reverse transcription polymerase chain reaction. HD-5 message was invariantly expressed by normal vagina and ectocervix and inflamed fallopian tube, but variably expressed by normal endocervix, endometrium, and fallopian tube (60, 64, and 29% of specimens, respectively). Expression in endometrium was the highest during the early secretory phase of the menstrual cycle. Using immunohistochemistry and confocal microscopy, HD-5 peptide was localized in the upper half of the stratified squamous epithelium of the vagina and ectocervix, with the intensity of cellular staining increasing toward the lumen. In positive endocervix, endometrium, and fallopian tube specimens, HD-5 was located in apically oriented granules and on the apical surface of a proportion of columnar epithelial cells. Using Western blot analysis, secreted HD-5 was detected in cervicovaginal lavages, with the highest concentrations found during the secretory phase of the menstrual cycle. We hypothesize that HD-5 is an intrinsic component of the female urogenital innate immune defense system and that its expression may be modulated by hormonal and proinflammatory factors.