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Biomedical subjects

V Polli

Publications and source records attributed to V Polli.

21 records · Page 2Linked to original sources

Electromechanical activities of human uteri during extra-corporeal perfusion with ovarian steroids.

A new experimental system was designed to study human uterine activities based on the extra-corporeal perfusion of isolated human uteri. Electromechanical activities in the uterine wall were recorded using bipolar silver-silver electrodes, endoluminal pressure catheters and a dedicated acquisition, storage and analytical system. The electrical signals recorded were isolated spikes and rhythmic activities; the last being primarily associated with organized mechanical events. Perfusion media containing 17 beta-oestradiol alone or with progesterone were used for those uteri obtained during proliferative (n = 5) or secretory (n = 5) phases of the menstrual cycle, respectively. Progesterone caused a reduction of frequency (P < 0.001) and duration (P < 0.001) of the rhythmic electrical activity, and decreased the endoluminal pressure at both detection sites (P < 0.01). 17 beta-Oestradiol increased both frequency (P < 0.001) and duration (P < 0.001) of the rhythmic electrical activity as well as the endoluminal pressure at two different detection sites (3 and 5 cm from the fundus) (P < 0.05). Significant differences between the fundus and cervix sites in the uterine wall were detected. In conclusion, uterine perfusion would be useful to examine the effects of uterotonic and tocolytic drugs before administration to humans, at no risk to the patients. Oestrogens increase and progesterone decreases both electrical and mechanical uterine activities.

Action Potentials↗

Factors regulating interaction between trophoblast and human endometrium.

Implantation is a crucial step in human reproduction. Disturbances of this process are responsible for pregnancy failure after both in vivo and in vitro fertilization. The endometrium provides the implanting embryo with a unique substratum where the embryo communicates with biochemical signals, attaches itself, penetrates and grows without blood circulation. The highly proliferative phase of the cytotrophoblast, during early human embryogenesis, may be due to endogenous production of growth factors that may establish autocrine/short range paracrine stimulator loops which explain the tumor-like properties of these tissues. Endometrial BM penetration and stroma invasion may be due to the proteolytic capability of the human embryo. It is suggested that collagenase and the urokinase-like plasminogen activator are responsible for this activity. To clarify the molecular mechanisms involved in human embryo implantation several models are suggested: culture of blastocysts, culture of endometrial cells, and endometrial explant co-culture. Human blastocysts cultured with whole perfused human uteri make it possible to recognize some aspects of the entire implantation process and give us the possibility of improving the benefits provided by new technologies in reproductive medicine and reducing embryonic loss at an early stage.

Endometrium↗

Basement membrane in human endometrium: possible role of proteolytic enzymes in developing hyperplasia and carcinoma.

Basement membranes (BM) are elements of the extracellular matrix that are essential for growth and differentiation of tissues. Several collagenolytic enzymes of tumor cells are involved in degradation of the extracellular matrix; growth and inhibitor factors [e.g. Epidermal Growth Factor (EGF), Transforming Growth Factors alpha and beta (TGF-alpha, beta)] seem to be involved in the extracellular matrix formation and degradation. To establish a possible association between the presence of collagenase (C), urokinase-type plasminogen activator (uPA) and the neoplastic growth of the endometrium, 44 endometrial specimens (14 proliferative, 11 secretive, 7 adenomatous hyperplasia, 12 adenocarcinoma) were studied using immunohistochemistry with antisera for C, uPA, EGF receptors and TGF-alpha. Immunostaining for collagenase revealed a positive reaction in moderately differentiated adeno-carcinoma without staining the normal and hyperplastic endometrium. A progressive increase in uPA immunostaining was observed in proliferative and neoplastic endometrium. TGF-alpha and its receptor (EGFr) were stained in proliferative and more clearly in hyperplastic and carcinomatous endometrium. In conclusion, BM play an important role in proliferation and differentiation of human endometrium; their degradation influences estrogen transportation from blood to the stroma. Endometrial BM degradation is associated with the presence of collagenolytic enzymes and growth factors.

Adult↗