B A Britton | PubMed Health

PubMed1993

Action of tolytoxin on cell morphology, cytoskeletal organization, and actin polymerization.

Tolytoxin, a cytostatic, antifungal macrolide produced by blue-green algae of the genus Scytonema, is a potent, reversible inhibitor of cytokinesis in cultured mammalian cells. Treatment of KB cells with 2-16 nM tolytoxin results in profound morphological changes, beginning with the formation of zeiotic processes and culminating in nuclear protrusion. In L1210 cells, cytokinesis is inhibited by as little as 2 nM tolytoxin, while karyokinesis proceeds normally, resulting in polynucleation. Tolytoxin specifically disrupts microfilament organization in A10 cells, while having no apparent effect on microtubules or intermediate filaments. Tolytoxin inhibited actin polymerization in vitro and also caused the depolymerization or fragmentation of F-actin in vitro. Tolytoxin exhibits effects that closely resemble those of cytochalasin B but is effective at concentrations 1/50-1/1,000 that of cytochalasin B.

Actins↗

PubMed1993

Endometrial histology after electrocoagulation using different power settings.

OBJECTIVE: To study endometrial histology after electrocoagulation in an in vitro model using 50 watts (W) and 100 W of coagulation current and determine the depth of endometrial destruction and survival, if any, of glands beneath this zone. DESIGN: Twenty fresh uteri of similar weights and dimensions were obtained from patients undergoing hysterectomy for benign disease. Specimens were bivalved into anterior and posterior walls and each wall divided in half. Endometrial electrocoagulation was carried out with a 5-mm probe at 50 W and 100 W applied to anterior and posterior quarters of the specimen, respectively. The adjacent untreated endometrial surfaces served as controls. Specimens were formalin-fixed, embedded in paraffin, and sections stained with hematoxylin and eosin. MAIN OUTCOME MEASURES: The number and morphology of the endometrial glands were counted and classified manually for each section and compared between each power setting and controls. RESULTS: Histologic examination revealed morphologically normal glands in all specimens beneath the zone of destruction regardless of power setting. Both power settings produced significant focal and diffuse glandular and stromal destruction when compared with controls. Significant differences were noted in the number of normal glands after treatment with 50 W (71.33 glands +/- 76.44 [mean +/- SD]), 100 W (21.11 +/- 35.71) and untreated controls (240.16 +/- 110.81). Tissue destruction increased with increasing power, and there were significant differences in the percentage of morphologically normal, surviving glands between 50 W (11.7% +/- 11.4% [mean +/- SD]) and 100 W (4.9% +/- 10.9%). CONCLUSION: These data suggest that electrocoagulation may result in a variable degree of endometrial destruction dependent on power. Viable glands and stroma may survive beneath the zone of destruction regardless of power. Such variations in endometrial insult in an in vitro model may explain, in part, the variable clinical results of endometrial electrocoagulation. The survival of glands beneath the zone of destruction in this model raises the theoretical concern for occult malignant changes and leaves open to question the exact role and mode of hormonal therapy during the menopause after endometrial ablation.

Electricity↗

PubMed1982

Endometrial change in the annual reproductive cycle of the mare.

Cervical and endometrial swabs were taken from 7 mares at various stages of the oestrous cycle. There was no consistent pattern of cell change throughout the cycle. The dominant cell in smears from normal mares was the columnar epithelial cell, especially in smears obtained during oestrus. A ciliated columnar epithelial cell was found much less frequently but appeared more often in smears before oestrus. Endometrial biopsies were also collected from 7 mares at intervals 2-3 weeks over an 8-month period from the beginning of spring to the end of autumn. There was no obvious change in the endometrial histology during this time. No evidence of acute or chronic inflammatory change was found in sequential biopsies. The inflammatory response to a single endometrial biopsy and subsequent endometrial biopsies, as measured by exfoliative cytology 48 h after biopsy, was minimal. Bacteria were recovered after aerobic culture of cervical swabs on more occasions 48 h after than before uterine biopsy, but they were considered not to be significant.

Animals↗