title: Enzyme histochemistry on human placental trophoblasts: the effect of fixation delay on enzyme activity.
abstract: We examined the effect of time delay in tissue fixation on enzyme histochemically detectable enzyme activity and its localization in term human placental trophoblasts. Four placental enzymes, alkaline phosphatase, acid phosphatase, glucose-6-phosphatase, and cytochrome c oxidase, were studied. A fixation delay of 15 min did not markedly alter the activity or distribution pattern of the four enzymes, excepted for a slight reduction in cytochrome c oxidase activity and the appearance of dilated endoplasmic reticula positive for glucose-6-phosphatase. A fixation delay of 60 min abolished cytochrome c oxidase activity, but the activities of the other three enzymes remained positive. When the placental tissue was stored at 4 degrees C without cutting for 24 h before fixation, cell degeneration occurred. However, alkaline phosphatase activity was still clearly demonstrable. In enzyme histochemistry, ,,immediate" fixation is superior, but even if this cannot be performed, the placentas, especially when they are from patients with rare disorders, should not be discarded. Observations made here will be useful for clinician's attempting enzyme histochemistry in organs other than the placenta.
authors.affiliation: Department of Obstetrics and Gynecology, Jichi Medical School, Tochigi, Japan. matsushi@jichi.ac.jp
authors.forename: S
authors.initials: S
authors.lastname: Matsubara
authors.forename: T
authors.initials: T
authors.lastname: Takizawa
authors.forename: I
authors.initials: I
authors.lastname: Sato
mesh_terms: D000135:Acid Phosphatase / Q000032:analysis* / Q000378:metabolism; D000469:Alkaline Phosphatase / Q000032:analysis* / Q000378:metabolism; D003576:Electron Transport Complex IV / Q000032:analysis* / Q000378:metabolism; D005260:Female; D005952:Glucose-6-Phosphatase / Q000032:analysis* / Q000378:metabolism; D006651:Histocytochemistry; D006801:Humans; D011247:Pregnancy; D014327:Trophoblasts / Q000201:enzymology*
chemical_list: D003576:Electron Transport Complex IV; D000469:Alkaline Phosphatase; D000135:Acid Phosphatase; D005952:Glucose-6-Phosphatase