Characterization of a microvillous membrane preparation from human placental syncytiotrophoblast: A morphologic, biochemical, and physiologic study

Smith, Carl H.; Nelson, D. F.; King, Barry F.; Donohue, T. M.; Ruzycki, S. M.; Kelley, Lucky K.

doi:10.1016/0002-9378(77)90686-x

Cited by 162 publications

(45 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Preparation of human placental brush-border membranes-Brush-border membranes were prepared according to the method described by Smith et al [16] and modified by Booth et al [17]. Briefly, after removal of the umbilical cord and amniotic membranes, tissue pieces weighing 20-30 g were dissected and washed four times with cold (4 °C) phosphate buffered saline (PBS; 83 mM NaCl, 22.2 mM Na 2 HPO 4 , 5.5 mM KH 2 PO 4 , pH 7.4).…”

Section: Methodsmentioning

confidence: 99%

Role of P-glycoprotein in transplacental transfer of methadone

Nanovskaya

Nekhayeva

Karunaratne

et al. 2005

Biochemical Pharmacology

View full text Add to dashboard Cite

Methadone is the therapeutic agent of choice for treatment of the pregnant opiate addict. However, little is known on the factors affecting its concentration in the fetal circulation during pregnancy and how it might relate to neonatal outcome. Therefore, a better understanding of the function of placental metabolic enzymes and transporters should add to the knowledge of the role of the tissue in the disposition of methadone and its relation to neonatal outcome. We hypothesized that the expression and activity of the placental efflux transporter P-glycoprotein (P-gp) would affect the transfer of methadone to the fetal circulation. Data obtained utilizing dual perfusion of placental lobule and monolayers of Be-Wo cell line indicated that methadone is extruded by P-gp. Transfer of methadone to the fetal circuit was increased by 30% in the presence of the P-gp inhibitor GF120918 while the transfer of paclitaxel, a typical substrate of the glycoprotein, was increased by 50%. In the Be-Wo cell line, methadone and paclitaxel uptake was also increased in the presence of the P-gp inhibitor cyclosporin A. Moreover, the expression of P-gp in placental brush-border membranes varied between term placentas. Taken together, these data strongly suggest that the concentration of methadone in the fetal circulation is affected by the expression and activity of P-gp. It is reasonable to speculate that placental disposition of methadone affects its concentration in the fetal circulation. If true, this may also be directly related to the incidence and intensity of neonatal abstinence syndrome (NAS).

show abstract

Section: Methodsmentioning

confidence: 99%

Role of P-glycoprotein in transplacental transfer of methadone

Nanovskaya

Nekhayeva

Karunaratne

et al. 2005

Biochemical Pharmacology

View full text Add to dashboard Cite

show abstract

“…Protein of placental microvilli membrane was prepared according to the procedures of Smith et al (1974Smith et al ( , 1977 and Smith and Brush (1978) with some modi®cation (Liao et al, 1992;Luo et al, 1996). In brief, portions of placenta (about 50 g) were rinsed rapidly in ice-cold Kreb's physiological saline to remove much of the blood.…”

Section: Preparation Of Membranementioning

confidence: 99%

Expression of ferritin receptor in placental microvilli membrane in pregnant women with different iron status at mid-term gestation

et al. 2001

Eur J Clin Nutr

View full text Add to dashboard Cite

Objective: The effect of iron status in pregnant women on expression of ferritin receptor in placental microvilli membrane at mid-term gestation was investigated. Design: Ferritin receptor binding sites and dissociation constants (K d ) were determined in specimens of placental microvilli from 30 pregnant women at mid-term gestation and six women at term-delivery. Results: The ferritin receptor binding sites in the placental microvilli membrane in pregnant women with mild iron de®ciency and moderate iron de®ciency anemia were signi®cantly higher then those in pregnant women with normal iron status. However, no signi®cant difference was found between pregnant women with severe iron de®ciency anemia and with normal measurements. No signi®cant differences of K d values were detected between pregnant women with normal iron status and those with iron-de®ciency. Data also revealed that the ferritin receptor binding sites in placental microvilli membrane and K d values at mid-term gestation did not differ signi®cantly from those at term gestation. Conclusion: Lower iron status in pregnant women could lead to an increase in expression of ferritin receptor in placental microvilli membrane at mid-term gestation while the dissociation constant of ferritin receptor remains unchanged. This implies that the regulation of maternal ± fetal iron homeostasis via the ferritin receptor-mediated pathway is achieved by changes in the numbers of ferritin receptors rather then binding properties. Sponsorship: China Natural Science Foundation and The Hong Kong Polytechnic University. Descriptors: ferritin receptor; placental microvilli; iron status; pregnant women; maternal-fetal iron homeostasis

show abstract

“…Placental vesicles were prepared from human term placenta (Smith et al, 1977 (Figure 3c and d). This was maximal towards the periphery of the lung from 8 to 10 weeks.…”

Section: Immunocytochemistrymentioning

confidence: 99%

Pattern of expression of c-erbB-2 oncoprotein in human fetuses

Quirke

Pickles²,

Tuzi³

et al. 1989

Br J Cancer

View full text Add to dashboard Cite

S_ry 1The pattern of expression of the c-erbB-2 oncoprotein was investigatdd in whole mount preparations of 11 human fetuses by immunocytochemistry using two polyclonal antibodies, 20N and 21N. c-erbB-2 was widely expressed within all three germ layers. Expression remained relatively constant in epitheliaL mesodermal and extraembryonic tissues, but varied over time during the development of the fetal skeleton. Western blotting failed to detect c-erbB-2 in normal fetal tissues but did confirm expression in a microvillous membrane preparation of placenta. c-erbB-2 expression is widespread in the human fetus and occurs at an earlier stage than epidermal growth factor receptor.The c-erbB-2 proto-oncogene encodes a 4.6 kb mRNA which specifies a 190,000 molecular weight glycoprotein with tyrosine kinase activity. This 1,255 amino acid protein reveals extensive sequence homology with the epidermal growth factor receptor (EGF-R), but unlike EGF-R, no ligand has yet been identified (for a review see Gullick & Venter, 1989). Amplification of the c-erbB-2 proto-oncogene has been demonstrated in a wide range of adenocarcinomas including those of the breast (Slamon et al., 1987;Venter et al., 1987;Van de Vijver et al., 1987, 1988, stomach (Yokota et al., 1986(Yokota et al., , 1988, salivary gland (Semba et al., 1985), kidney (Yokota et al., 1986) and lung (Cline & Battifora, 1987) and appears to be related to prognosis in breast cancer (Slamon et al., 1987;Zhou et al., 1987). The presence of amplification in colonic adenocarcinoma has been reported (Tal et al., 1988), but it is unclear if this is a frequent event as it has not been detected by other workers (Yokota et al., 1986).The physiological action of the c-erbB-2 receptor protein is unknown and its distribution in human fetal and normal tissue has yet to be fully characterised. c-erbB-2 mRNA was widely expressed in organ digests from a single human fetus (Coussens et al., 1985) but its site within these tissues has not been identified. Expression of the neu oncogene, the rat equivalent of c-erbB-2, with which it has 88% homology, has been described in fetal rats (Kokai et al., 1987) al., 1985, 1986 Bernards et al., 1987) or anti-oncogene therapy.We have investigated the presence and distribution of the c-erbB-2 protein by immunocytochemistry and Western blotting in a series of human fetuses and placentae using two previously described polyclonal antibodies . Materials and methodsFifteen whole human fetuses from spontaneous abortions were collected over several years and stored in 10% formalin. After processing and embedding four were discarded owing to the presence of mild to severe autolysis, leaving 11 well preserved fetuses for study. Estimated gestational ages were determined by a combination of foot length, crown rump length and histological assessment of tissue maturity and ranged from 6 to 12 weeks. Fetuses larger than 12 weeks could not be sectioned whole and were therefore not included in this study. Tissue from first trimester, second trimester and term p...

show abstract

Characterization of a microvillous membrane preparation from human placental syncytiotrophoblast: A morphologic, biochemical, and physiologic study

Cited by 162 publications

References 30 publications

Role of P-glycoprotein in transplacental transfer of methadone

Role of P-glycoprotein in transplacental transfer of methadone

Expression of ferritin receptor in placental microvilli membrane in pregnant women with different iron status at mid-term gestation

Pattern of expression of c-erbB-2 oncoprotein in human fetuses

Contact Info

Product

Resources

About