The decidualized endometrium during the first trimester of pregnancy synthesizes and secretes a 32-kDa insulin-like growth factor-binding protein (termed hIGFBP-1) at high levels. IGFBP-1 is the major soluble protein product of this tissue and is principally localized to the differentiated endometrial stromal cell, the decidual cell. In the present study long term culture of stromal cells from the nonpregnant endometrium have been employed to elucidate the hormonal requirements for IGFBP-1 production. Immunoreactive IGFBP-1 was undetectable in control cultures. However, inclusion of medroxyprogesterone acetate (MPA) induced rates of 0.35 +/- 0.09 microgram/0.1 mg cell DNA.day (mean +/- SEM; n = 5) after 20-30 days. In these cultures cells exhibited morphological changes consistent with decidual cell differentiation. In all cultures removal of MPA after exposure for 10-16 days, with or without subsequent inclusion of relaxin (RLX), increased production of IGFBP-1 450- to 4600-fold to rates of 150-710 micrograms/0.1 mg cell DNA.day or 26-131 micrograms/10(6) cells.day on days 24-26. The rates tended to be higher with the inclusion of RLX and were sustained in contrast to cultures without RLX, where rates fell by day 30. Individual cultures responded differently to RLX when added from the initiation of culture, with either a response similar to MPA alone or a cyclical change in production, achieving maximal rates of 190-290 micrograms/0.1 mg cell DNA.day. Cultures in which RLX alone induced high IGFBP-1 high production were obtained from endometrium during the progesterone-dominated luteal phase. In cultures exhibiting high rates of immunoreactive IGFBP-1 production, the protein represented their major secretory protein product. This was confirmed by [35S]methionine incorporation and the presence of IGFBP-1 as the predominant protein in serum-free culture medium. The immunoreactive IGFBP-1 isolated from culture medium was found to be identical, by a number of criteria, with IGFBP-1 derived from decidual tissue. These results were consistent with a primary role of progestin exposure, whether in vivo or in vitro, in converting endometrial stromal cells to cells potentially able to exhibit the high rates of IGFBP-1 production typical of the decidualized endometrium of pregnancy.
Non-invasive ventilation (NIV) is used to treat acute respiratory failure. Nebulised drugs can be delivered concurrently with NIV or during breaks from ventilatory support. We hypothesised that the amount of nebulised salbutamol inhaled when delivered via bi-level ventilation would be no different to the amount available directly from the same nebuliser. A standard bi-level ventilation circuit was attached to a lung model simulating adult respiration. Drug delivery was compared when salbutamol (5 mg) was nebulised at different positions in the circuit and separately, with no ventilator. The amount of salbutamol contained in various particle size fractions was also determined. Nebuliser position within the NIV circuit was critically important for drug delivery. Optimal delivery of salbutamol occurred with the expiration port between the facemask and nebuliser (647+/-67 micro g). This was significantly better than nebulisation without the ventilator (424+/-61 micro g; P < 0.01). Delivery when the nebuliser was positioned between the facemask and expiration port was 544+/-85 micro g. The amount of salbutamol contained in particles < 5 micro m was significantly increased when the nebuliser was used in conjunction with bi-level ventilation (576+/-60 micro g vs 300+/-43 micro g, P < 0.001). We conclude that nebulised bronchodilator therapy, using a Cirrus jet nebuliser, during bi-level ventilation increases respirable particles likely to be inhaled when the nebuliser is optimally positioned within the circuit.
Pregnancy-associated endometrial alpha 1-globulin (alpha 1-PEG) is quantitatively the major secretory protein product, synthesized and secreted in vitro, of the human decidualized endometrium during pregnancy. This protein has been purified from cytosolic extracts of this tissue and has now been characterized as a 32 kDa somatomedin/insulin-like growth factor (IGF)-binding protein. Immunoreactive alpha 1-PEG isolated from amniotic fluid exhibited identical physiochemical properties and IGF-I-binding characteristics. In cytosolic extracts of pregnancy endometrium, in incubation medium of this tissue and in amniotic fluid, the 32 kDa protein represented the major alpha 1-PEG immunoreactive protein and major IGF-I-binding component. Purified alpha 1-PEG and incubation medium of pregnancy endometrium competed for IGF-I with placental membrane IGF receptors in vitro. The implications of the endometrial source of IGF-I-binding protein are discussed with reference to the origin of the amniotic fluid and serum small Mr IGF-binding protein and to the suggested paracrine effect upon trophoblast proliferation.
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