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Several layers of cumulus cells surround the oocyte in the antral ovarian follicle throughout the follicular development until ovulation. The cumulus cells play an important supportive and regulative role in oocyte development and maturation via intercellular communications between oocytes and cumulus cells. Using the differential display reverse transcriptase polymerase chain reaction (DD-RT-PCR) and semi-quantitative RT-PCR methods, we compared the mRNA expression patterns in porcine oocytes from two sources: cumulus-oocyte complexes (COCs) and naked oocytes (NOs). After a small scale screen, 14 differentially expressed mRNAs were cloned, sequenced, and their expression patterns were verified by semi-quantitative RT-PCR. It was confirmed that four mRNAs including three genes (PELP1, Myo5b and CAST) and a new EST (Expressed Sequence Tag) are expressed preferentially in the oocytes of COCs rather than in NOs. Previous studies of the three genes suggested that they are mainly involved in oestrogen receptor regulation, membrane trafficking, organelle transport, cellular signalling and some other cellular processes. These results suggest that the aberrant of gene expression patterns detected in the oocytes of NOs compared with COCs explains their reduced quality in terms of development and maturation. In conclusion, these differentially expressed mRNAs may be involved in cellular interactions between oocytes and cumulus cells and thus could be considered as essential genes for the competence of oocytes. [ABSTRACT FROM AUTHOR]

Objective: To evaluate epithelial-mesenchymal interactions in morphological homeostasis through histologically orientated observations on the reduced enamel in epithelium., Study Design: Specimens were taken from impacted molar sites in 20 patients using the surgery. These were processed using standard histological, pathological and biochemical techniques. Slides were observed with a Nikon Eclipse E-600, Plan Apo piece, Microscopy, and photography was done using a Nikon Coolpix 990 digital camera., Results: Radiolucent lesions displayed the supporting fibrous connective tissue wall with stratified squamous epithelium lining mostly. None of the specimens displayed prominent CAM 5.2, and anti-human K7 reacuvity, and PAS positive staining., Conclusion: While the results of this study suggest that the reduced enamel epithelium showed a lower tendency in cell cycle, it does indicate that a histologically oriented study of reduced enamel epithelium is needed for the understanding of epithelial-mesenchymal interactions in morphogenesis.