Immunohistochemical localization of nitric oxide synthases in human cervix. (a) inducible nitric oxide (iNOS) localized to the stroma in preterm labour (b) iNOS localized to the squamous epithelium in preterm not in labour patient. In each of the biopsies iNOS was localized in the stroma and the epithelium. (c) Endothelial nitric oxide (eNOS) localized to the vascular endothelium in all biopsies. This is collected from a woman in preterm labour. Neuronal nitric oxide (bNOS) had a distinct staining and was generally localized to the: (d) basal membrane of the squamous epithelium, picture from a women in preterm labour, (e) the stroma, biopsy from at term in labour patient, (f) the cervical glands, this sample from at term in labour patient. Original magnification × 200, scale bar 50 μm.