Repair of human endometrium after menstruation and preparation of the endometrium for implantation involves profound angiogenic changes. Vascular endothelial cell growth factor (VEGF) is a recently identified growth factor with significant angiogenic properties. Four species of mRNA encoding VEGFs were identified in human endometrium and myometrium. All species were present throughout the menstrual cycle. Two species, VEGF165 and VEGF121, were present in peripheral leukocytes, indicating tissue-specific splicing of the two other VEGF transcripts. In situ hybridization of mRNA encoding VEGF was not restricted to vascular smooth muscle but was present in epithelial and stromal cells of endometrium throughout the cycle, and the distribution changed during the course of the cycle. All four species of VEGF were expressed by the endometrial carcinoma cell lines Ishikawa, HEC 1-A, and HEC 1-B. Estradiol increased steady-state levels of mRNA encoding VEGF in a dose- and time-dependent manner in HEC 1-A cells. Conditioned medium from these cells possessed angiogenic activity that was depleted by passage through a heparin affinity column. None of the cell lines demonstrated mRNA for acidic or basic fibroblast growth factor (FGF), despite previous reports of the identification of immunoreactive basic FGF in HEC 1-A and HEC 1-B cells. These findings show that VEGFs, not FGFs, are the principal angiogenic growth factors secreted by these cells and that human endometrium expresses a secreted angiogenic growth factor whose site of expression changes during the menstrual cycle.

Entamoeba histolytica is an intestinal parasite causing significant morbidity and mortality worldwide. More tools are needed to understand the epidemiology and molecular pathogenesis of amebiasis. A cDNA library was constructed by using poly(A)+ RNA isolated from an axenic strain of E. histolytica, HM1:IMSS, which expresses a pathogenic isoenzyme pattern (zymodeme). Differential screening of the library yielded a strain-specific 3' polyadenylated cDNA clone, C2, possessing nine 26-nucleotide tandem repeats. RNA and DNA transfer blot analysis of four axenic strains of E. histolytica possessing the same pathogenic zymodeme revealed that the gene is present and expressed in pathogenic E. histolytica HM1:IMSS and 200:NIH but is not present in pathogenic strains HK-9 and Rahman. In addition, Southern blot analysis using the C2 clone showed heterogeneity of genomic organization between HM1:IMSS and 200:NIH. DNA dot blot hybridization analysis demonstrated that cDNA clone C2 was also able to distinguish xenically cultured E. histolytica strains possessing pathogenic zymodemes from those possessing nonpathogenic zymodemes and could detect as few as 100 amebic trophozoites. We conclude that C2 is a strain-specific E. histolytica cDNA clone that, in conjunction with other E. histolytica-specific probes, could serve as a useful epidemiologic tool.

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