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Query: UMLS:C0432222 (SEM)
 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The mechanisms that underlie progestogen-induced endometrial breakthrough bleeding are poorly understood. The aim of the present study was to quantify endometrial microvascular density in 54 controls and 42 women with 3-12 months' exposure to Norplant (levonorgestrel subdermal contraceptive implant) and to correlate it with bleeding pattern, endometrial histology, and peripheral plasma oestradiol and progesterone concentrations. Endometrial biopsies were processed routinely and sections immunostained using anti-CD34 antibody to identify vascular endothelial cells. Menstrual record card data were analysed using World Health Organization definitions. The mean microvascular density (+/- SEM) for control samples was 186 +/- 8 vessels/mm2, and there were no significant differences across the cycle. Norplant user's endometrial microvascular density was significantly elevated above controls (294 +/- 18 vessels/mm2, P = 3.36 x 10(-8)). Endometrial microvascular density in Norplant users did not correlate with oestrogen concentrations prior to biopsy, bleeding patterns or endometrial histology. The results from this study show that women receiving Norplant have significantly increased endometrial microvascular density compared to controls. Another finding from this study was that bleeding in Norplant users often occurred from thin atrophic endometrium. These results provide new insights into the physiological mechanisms that may be involved in progestogen-induced endometrial bleeding.
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PMID:Endometrial microvascular density during the normal menstrual cycle and following exposure to long-term levonorgestrel. 825 25

Irregular menstrual bleeding in users of hormonal contraception represents the single major reason for discontinuation of these contraceptive methods. The mechanisms which underlie these bleeding disturbances are poorly understood, but appear to be associated with changes in the endometrial microvasculature following abnormal patterns of sex steroid exposure. Endometrial microvascular density is known to be increased in users of the low-dose levonorgestrel contraceptive implant, Norplant. This study explores microvascular density in other conditions of spontaneous (post-menopausal) and induced (danazol and goserelin) endometrial atrophy. Endometrial biopsies were fixed, paraffin-embedded and sections were immunostained using anti-CD34 antibody to identify vascular endothelial cells. The mean microvascular density (+/-SEM) for control samples was 186 +/- 8 vessels/mm2. There were no statistically significant changes in vascular density observed across the menstrual cycle. Mean microvascular density in spontaneous and induced endometrial atrophy did not differ significantly from that observed in the control population. The mean microvascular density was 230 +/- 17 vessels/mm2 in 31 postmenopausal women, 269 +/- 67 vessels/mm2 in 25 subjects treated with danazol was and 191 +/- 45 vessels/mm2 in nine subjects treated with goserelin. These findings suggest that the mechanisms controlling microvascular density in conditions of endometrial atrophy may vary according to the nature of the atrophic stimulus.
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PMID:Microvascular density in conditions of endometrial atrophy. 892 Oct 81

Progestogen-only contraception is almost invariably associated with changes in menstrual bleeding patterns. Changes in the endometrial vasculature, and in particular an increase in vascular fragility, may contribute to this bleeding. In this study, endometrial vascular density and endothelial cell basement membrane components were examined using immunohistochemistry before and after insertion of Norplant. Endometrial vascular density was increased from a mean (+/- SEM) of 189.6 +/- 7.0 vessels/mm2 during the control cycle to 253.9 +/- 80.7 vessels/mm2 at 2-13 weeks of Norplant exposure, and to 212.7 +/- 12.9 vessels/mm2 at 14-42 weeks. During the control cycle, a mean of 161.4 +/- 4.5 vessels/mm2 stained for collagen IV (85% of all vessels), while at 2-13 weeks, 144.5 +/- 13.0 vessels/mm2 stained for collagen IV (57% of all vessels) (t ratio = 2.08, P = 0.0057). By 14-42 weeks, 71% of vessels (151.0 +/- 9.8) vessels/mm2 were surrounded by collagen IV. This was not significantly different from control values (t ratio = 2.03). Endometrial vascular laminin was also reduced following Norplant insertion, from a mean of 176.0 +/- 4.2 vessels/mm2 in the control cycle (93% of vessels), to 156.3 +/- 6.7 vessels/mm2 at 2-13 weeks of exposure (57% of vessels) (t ratio = 2.08, P = 0.01). By 14-42 weeks of exposure to Norplant, 162.5 +/- 9 vessels/mm2 (76%) stained for laminin. This was not significantly different from control values (t ratio = 2.04). Endometrial vascular heparan sulphate proteoglycan (HSPG) was reduced from 58.6 +/- 3.0 vessels/mm2 during the control cycle (31% of vessels) to 43.6 +/- 5.6 vessels/mm2 (only 17% of vessels) at 2-13 weeks (t ratio = 2.08, P = 0.025). At 14-42 weeks, only 19% of vessels stained for HSPG (41.3 +/- 5.8 vessels/mm2; t ratio = 2.04, P = 0.009).
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PMID:Changes in vascular basement membrane in the endometrium of Norplant users. 1022 2

The use of progestogens without oestrogen is commonly associated with irregular menstrual bleeding. Oestrogens and progestogens are both thought to influence endometrial perfusion; changes in endometrial perfusion may contribute to vascular fragility and breakdown. In this study, endometrial perfusion was measured using laser-Doppler fluxmetry in women in the secretory phase of the menstrual cycle before and 4-6 weeks after insertion of the low-dose long-acting levonorgestrel contraceptive implant system, Norplant. Endometrial perfusion was also measured in women exposed to Norplant for up to 19 months. There was no significant difference between endometrial perfusion in control cycles (27.2 flux units +/- 5.5, SEM) and at 4-6 weeks after Norplant insertion (16.3 flux units +/- 5.0), a time when irregular bleeding and spotting are common. Endometrial perfusion was no different from controls after longer periods of Norplant exposure (35.7 flux units +/- 7.2). No direct relationships between endometrial perfusion and plasma concentrations of ovarian steroid hormones were demonstrated. Short-term endometrial vasomotion was largely abolished during Norplant exposure.
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PMID:The measurement of endometrial perfusion in norplant users: a pilot study. 1078 58