No abstract

Light microscopic studies using a battery of basic dye stains combined with sialidase and hyaluronidase digestions indicated that the extensive basophilia of the maternal surface of the placental syncytium largely results from the presence of a non-sulfated mucosubstance specifically identified as hyaluronic acid. Ultrastructural examination of dialyzed iron (DI) stained specimens revealed that DI-positive filaments observed along the syncytial surface were removed by hyaluronidase digestion. Staining with the lectins, Concanavalin A or lentil bean hemagglutinin produced an intense and periodic pattern of staining that was not enzyme labile. Incubation of tissue sections in the enzyme solutions or control buffers allowed the lectins to penetrate the syncytial plasma membrane and stain material within the endoplasmic reticulum presumed to be human chorionic gonadotropin. The maternal surface exhibited essentially no reactivity for acid phosphatase but showed strong alkaline phosphatase activity with a periodic staining pattern. With each of the techniques used there was variability in the intensity of staining in different regions along the maternal surface, suggesting that functionally different zones may be identified cytochemically. Only minor differences were observed in the cytochemical reactivity of early compared with term placenta.Perhaps no other tissue is involved in as many diverse biological activities as the placenta. Comprising the interface between fetal and maternal organisms the maternal surface of the syncytiotrophoblast is the site of important transport processes. The reactivity of the placenta with a number of cytochemical procedures evidences the diversity and complexity of its physiologic activity (Boyd and Hamilton, '70). The present investigation inquired into the nature of the components of the plasmalemma of the syncytiotrophoblast, employing cytochemical methods for visualizing phosphatases possibly involved in transport and for localizing and characterizing mucosubstances. For the latter purpose, the dialyzed iron procedure for demonstrating acid mucosubstances and the Concanavalin A horseradish peroxidase technique of Bernhard and Avrameas ('71) for demonstrating mannose-and glucose-rich glycoproteins were employed. An additional method for visualizing glycoproteins introduced here employed two purified lectins from the lentil bean (Lens culinaris) designated LcH-A and LcH-B. The nature of the reactive mucosubstances was further evaluated by observing the effect of prior enzymatic digestions on the staining procedure. MATERIALS AND METHODSHuman placenta was obtained at 9-12 weeks of pregnancy following therapeutic abortion or at term following normal delivery. For light microscopic examination tissue was fixed for 24 hours in a 10% formalin-2% calcium acetate solution prior to routine paraffin embedding. Deparanized, rehydrated sections were stained with the dialyzed iron (Rinehart and Abul-Haj, 'Sl), alcian blue in 0. procedures for localizing and differentiating mucosubstanc...

Multivesicular bodies and related structures of the syncytiotrophoblast of human term placenta have been studied ultrastructurally and cytochemically. Circular profiles of vesicles termed pre-multivesicular bodies (premvb's) were observed often near Golgi complexes. Multivesicular bodies (mvb's with electron lucent matrices (L-mvb's), mvb's with electron dense matrices (D-mvb's), and dense bodies were also prevalent organelles of the syncytium. These organelles all exhibited dialyzed iron reactivity and staining characteristics suggesting that the organelles were related. Material within Golgi saccules, Golgi vesicles, vesicles of pre-mvb's, and vesicles of mvb's were all reactive with osmium zinc iodide (OZI). This OZI reactivity further indicated a relationship between the organelles. The matrix of the mvb's exhibited variable reactivity for acid phosphatase (AcPase) but such activity was not encountered in Golgi elements of syncytiotrophoblast. It is suggested that the mvb's of human term placental syncytium are likely formed by aggregation of vesicles of Golgi origin into pre-mvb's, that the pre-mvb's are then capable of transforming into L-mvbs, D-mvb's, and finally into dense (residual) bodies. It is also suggested that mvb's may function in the selective hydrolysis and transport of endocytosed proteins, including globulins. Additional bodies with intense acid phosphatase activity were designated elongate bodies. Other distinctive organelles designated dense cored spheroids were occasionally observed in the syncytioplasm.The placental syncytiotrophoblast functions as a barrier between the fetal and maternal vascular systems, as well as in the transport of nutrients and metabolic wastes (Grosser, '27; Hagerman and Villee, '60; Boyd and Hamilton, '70), and is apparently the site of synthesis and secretion of both protein and steroid hormones (Villee, '69; Wattenberg, '58; Benirschke and Driscoll, '67; Pierce and Midgley, '63; Dreskin, Spicer and Greene, '70). Thus, it is not surprising that the syncytioplasm is packed with a diverse population of inclusions and organelles. Among the numerous ultrastructural studies of the human pIacenta are investigations that have associated certain of the syncytioplasm organelles with a particular function (Tighe, Garrod and Curran, '67; Dreskin et al., '70; Burgos and Rodriguez, '66; Sato, '66). However, none has made a careful attempt to describe and classify the inclusions and organelles of the syncytiotrophoblast, a ANAT. REC., 175: 15-36. logical prerequisite to understanding their functional significance. This investigation is the beginning of an effort of this type and considers in detail the multivesicular bodies and related structures of the syncytium of human term placenta, particularly emphasizing morphologicaI and certain cytochemical characteristics of the multivesicular bodies (mvb's). MATERIALS AND METHODSTissue was excised as quickly as possible from full term placenta obtained postpartum or by Cesarian section. Some of the specimens were fixed in 1....

To improve cell recovery of trophoblast and nucleated red blood cells from maternal blood for diagnosis of chromosomal abnormalities, we have investigated the use of a magnetic sorting system that utilizes a ferrofluid. The main advantage of this system is that the beads used are small enough to allow visualization of chromosome‐specific sequences by fluorescence in situ hybridization (FISH). The ferrofluid was validated using MAb340, a trophoblast‐specific antibody, and anti‐CD71, used to sort for nucleated red blood cells. Antigen‐positive cells could be efficiently sorted from a 1000‐fold excess of antigen‐negative cells and easily stained by FISH. We are currently evaluating its use on maternal blood samples. © 1997 John Wiley & Sons, Ltd.

Human and rabbit blood cell surfaces were stained by a lectin-horseradish peroxidase (HRP) technique using either concanavalin A (Con A) or Lens culinaris hemagglutinins (LcH). Intensity of staining of the human cells with the Con A-HRP method decreased in the order: platelets, mononuclear cells, granulocytes, erythrocytes. Cell surface staining of mature cells was similar to the bone marrow precursor cells as well as to leukemic blast cells. Surface staining of erythrocytes correlated with agglutinability of these cells with Con A or LcH. Differing ability of Con A and LcH to allow penetration of diaminobenzidine into myeloid cells indicated stearic differences in their binding to the cell surface. The Con A-HRP staining of cell surfaces was prevented on all cells by prior periodate oxidation and on cells other than erythrocytes by prior acetylation but was not altered by methylation or sialidase digestion.