Placenta localizing

Cr 27.8 d Determination of red blood cell volume, spleen imaging, placenta localization... 

The estrogens are a family of hormones synthesized in a variety of tissues. 17P-Estradiol is the primary estrogen of ovarian origin. In some species, estrone, synthesized in numerous tissues, is more abundant. In pregnancy, relatively more estriol is produced, and this comes from the placenta. The general pathway and the subcellular localization of the enzymes involved in the early steps of estradiol synthesis are the same as those involved in androgen biosynthesis. Features unique to the ovary are illustrated in Figure 42-7. 

Tamai et al. [30] cloned OATP-B from human brain and transporter mRNA has been detected in a number of other tissues including liver, lung, kidney, placenta, brain, heart and small intestine [26, 30]. Within the liver, OATP-B protein is local-... 

Within the OAT family, OAT4 is the only transporter expressed at appreciable levels in both the placenta and in the kidney [54]. The membrane localization of OAT4 within these tissues has not been examined. Steroid sulfates, and ochratoxinA are efficient transport substrates of OAT4, whereas PAH is weakly transported [54]. The functional importance of OAT4 in regulating placental permeability and renal drug elimination is currently unknown. 

Burton, PJ. and Waddell, B.J., Dual function of 1 lP-hydroxysteroid dehydrogenase in placenta Modulating placental glucocorticoid passage and local steroid action, Biol. Reprod., 60, 234, 1999. 

Kim et al. (67) P. placenta Polyclonal antiserum was produced to P. placenta extracellular metabolites red spruce and birch were degraded by P. placenta using the soil-block procedure degraded wood-block samples were prepared for TEM and the immunoelectron localization of wood-degrading enzymes Extracellular membrane structures (matrix) were observed surrounding hyphae, which degraded spruce and birch wood the matrix labeled positively with antisera produced to P. placenta extracellular metabolites... 

Brown-rot fungus (isolate MAD-698) was grown on sterile 12 mm glass slips placed on the surface of 2% (w/v) malt agar removed when about 50% covered were localized using colloidal gold labeled monoclonal antibodies to the B-l, 4-xylanase fraction of P. placenta-, enzymes were localized on the hyphal surface... 

Micales JA. Localization and induction of oxalate decarboxylase in the brown-rot wood decay fungus, Postia placenta. Int Biodeter Biodegrad 1997 39 125-132. 

Kim YS, GoodellB, Jellison J. Immuno-electron microscopic localization of extracellular metabolites in spruce wood decayed by brown-rot fungus, Postia placenta. International Research Group on Wood Decay, Stockholm, Sweden, 1990 1441. 

Primarily to elucidate transporter localization and function, vesicles enriched in trophoblast apical or basolateral membranes have frequently been utilized. To give a few instances, they have been used to investigate P-gp-mediated transport, mechanisms of transport of cationic compounds, drug interactions with nutrient transport, and differences in amino acid transport in pathological conditions of the placenta [36, 40-42], Briefly, for preparation of microvillus membrane vesicles the cord, amniochorion and decidua are removed from placenta, and the tissue cut on the maternal side. The mince is stirred to loosen... 

It needs to be mentioned here that there remains some controversy over the placental expression of P-gp as a function of gestational age. An immunohis-tochemical study done by Macfarland et al. showed that P-gp was localized to the microvillous border of trophoblasts in first trimester placenta, but not in term placenta [85], Subsequent studies refuted this to show that MDR1 mRNA is present throughout pregnancy [94], More recently, enzyme-linked immunosorbent assay (ELISA) performed in syncytial microvillous membrane showed that P-gp protein expression in early gestational age placenta is about... 

In contrast to P-gp and the MRP proteins, the breast cancer resistance protein (BCRP) contains six transmembrane domains and only one ATP-binding domain. It was first cloned from the breast cancer cell line MCF-7 selected in doxombicin, in the presence of the P-gp inhibitor verapamil. It is found in many human tissues, such as the placenta, small intestine, colon, and liver [133], It is localized to the apical membrane of epithelial cells of the small intestine and colon and to the bile canalicular membrane in the liver and is involved in reducing intestinal uptake, increasing hepatobiliary excretion, etc., leading to diminished oral bioavailability. cDNA sequences identical to BCRP and named MXR and ABCP, respectively, were independently isolated from human colon carcinoma cells and human placenta [134], BCRP requires... 

H.E. Meyer Zu Schwabedissen, M. Grube, B. Heydrich, K. Linnemann, C. Fusch, H.K. Kroemer, and G. Jedlitschky. Expression, localization, and function of MRP5 (ABCC5), a transporter for cyclic nucleotides, in human placenta and cultured human trophoblasts Effects of gestational age and cellular differentiation. Am J Pathol. 166 39 18 (2005). 

M. Nagashige, F. Ushigome, N. Koyabu, K. Hirata, M. Kawabuchi, T. Hirakawa, S. Satoh, K. Tsukimori, H. Nakano, T. Uchiumi, M. Kuwano, H. Ohtani, and Y. Sawada. Basal membrane localization of MRP1 in human placental tro-phoblast. Placenta. 24 951-958 (2003). 

Suzuki T, Fujiwake H, Iwai K (1980) Intracellular localization of capsaicin and its analogues, capsaicinoid, in Capsicum fruit. 1. Microscopic investigation of the structure of the placenta of Capsicum annuum var. annuum cv. Karayatsubusa. Plant Cell Physiol 21 839-853 Ohta Y (1963) Physiological and genetical studies on the pungency of Capsicum IV. Secretory organ, receptacles and distribution of capsaicin in the Capsicum fruits. Jap J Breed 12 179-183... 

Distribution, including accumulation of an absorbed substance, will be the same irrespective of the route of administration. However, distribution and accumulation at the site of apphcation (inhalation, oral, dermal) may depend on the route of administration. In such cases, local accumulation may occur and may be responsible for tissue damage. In these cases, systemic toxicokinetics of the substance may be of limited relevance for the risk assessment. It is generally not cmcial for risk assessment to determine the precise tissue distribution profile for a substance. In certain special cases, however, specific tissue distribution studies may assist or even be essential for the interpretation of available toxicological data. For example, it may be of interest to know whether the substance will cross the blood-brain barrier, the placenta barrier, or will accumulate in specific tissues. 

Heparin is prescribed on a unit (lU) rather than milligram basis. Tlie dose must be determined on an individual basis. Heparin is not absorbed after oral administration and therefore must be given parenterally. Intravenous administration results in an almost immediate anticoagulant effect. There is an approximate 2-hour delay in onset of drug action after subcutaneous administration. Intramuscular injection of heparin is to be avoided because of unpredictable absorption rates, local bleeding, and irritation. Heparin is not bound to plasma proteins or secreted into breast mUk, and it does not cross the placenta. 

The OAT4 was cloned from human kidney but is also expressed at appreciable levels in the placenta (54). In kidney, OAT4 is localized to the apical... 

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