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402 Placenta (I 991), Vol. 12
stage of the gestation also showed dependency on potential difference of the internal and external membrane.
The transport of L-alanine into the BBMV was markedly augmented at the later stage of gestation compared to that at the early stage of the gestation. On the basis of the double reciprocal plotting of the L-alanine concentration and the Naf-dependent uptake of L-alanine into the vesicles, K, and V,, were calculated as parameters of the Naf- dependent uptake of L-ala&e into the vesicles. K, in the early stage of gestation was 0.78 mu, and K, in the late stage of gestation was 0.80 mu. V,,,, (nmol/mgprotein/20 set) in the early stage of gestation was 0.62, and V,, in the late stage of gestation was 3.53.
From these results, it was considered that the placental active transport mechanism for L-alanine is the same in the early and late stages of gestation, and it was demonstrated that its transport activity increases remarkably in the late stage compared to the early stage of gestation.
MORPHOLOGICAL INVESTIGATION OF MICROSCOPIC MOLE Kozo Ito, Keiki Ohira & Kiichiro Noda (Department of Obstetrics and Gynaecology, Kinki University School of Medicine, Osaka, Japan)
Cases in which there is microscopically recognized cyst-formation of the placental villi are defined as microscopic mole, but the diagnostic criteria and biological behavior are not always clear cut. We examined diagnostic criteria and clinical management of this micro- scopic mole.
Villi were obtained from 40 cases of artificial abortion, 60 cases of spontaneous abortion and five cases of complete mole. The shape, branching and shade of the terminal villi were observed and then the minor axis ofvilli were measured. Central liquefaction, disappearance of villous vessels and proliferation of villous cells were observed.
Disappearance of villous vessels, central liquefaction and proliferation ofvillous cells were observed not only in cases of abortion but in normal villi, though less frequently. When the villi were below 1 mm in their minor axis, none of the findings, such as central liquefaction disappearance of villous vessels and proliferation of villous cells were outstanding. We could not distinguish cases whose minor axis of villi is above 1 mm from complete mole even when cyst-formation was not observed, and found occurrence of two cases of secondary tumor in them. Cases which meet the criteria are separated as microscopic moles in a meaning that a relationship with complete mole cannot be denied. The other cases are named hydropic degeneration.
WATER PERMEABILITY AND PATHWAYS OF WATER TRANSPORT ACROSS HUMAN PLACENTAL MICROVILLOUS AND BASAL MEMBRANES Thomas Jansson & Nicholas P. Illsley (Division of Maternal-Fetal Medicine, Department of Obstetrics, Gynecology & Reproductive Sciences, University of California, San Francisco, CA 94143-0556, USA)
The mechanisms of water transport across the human syncytiotrophoblast are poorly understood and water permeabilities are available only for the microvillous membrane. This
research was designed to define the pathways for water transport and to compare the osmotic water permeabilities of basal (BM) and microvillous (MVM) membranes. Paired MVM and BM were prepared simultaneously from normal term human placenta. The osmotic water permeability coefficient (Pr) was measured at 23°C from the time course of scattered light intensity following exposure of membrane vesicles to solute gradients. Pr for MVM measured using inwardly directed gradients of sucrose showed only small variations between 0 and 200 mOsm/kg (1.3-l .8 x 1 O-3 cm/s), while Pr for BM decreased linearly from 2.5 to 1 .O x 1 O--,’ cm/s with the increasing gradient. Pr was solute dependent inasmuch as Pr (raffinose) <: P,- (sucrose) < Pr (NaCl). This relationship was much more pronounced for BM. Pr values for MVM and BM measured using raffinose were 0.83 and 0.72 x lO-.j cm/s. The activation energy (Ed measured using a sucrose gradient was - 14 kcal/mol for both MVM and BM. Water transport was unaffected by HgC12, pCMBS and glucose-transport inhibitors. The high E, value for water transport and the failure to inhibit water transport are consistent with lipid-mediated water permeation across human placental membranes. These results suggest that while MVM and BM osmotic water permeabilities are similar, the membranes differ in their solute permeabilities.
HIV INFECTED CELLS IN THE HUMAN PLACENTA AS DEMONSTRATED BY IN-SITU HYBRIDIZATION AND IMMUNOSTAINING E. Jimenez’, E. Back?, E. Jaunia&, M. Ungera & M. Vogel” (aInstitute of Pathology, Department of Paediatric Pathology and Placentology, Universidtsklinikum Rudolf- Virchow Berlin (Charlottenburg), Germany and bDepartment of Obstetrics and Gynae- cology, Hopital Universitaire Erasme, Brussels, Belgium)
The aim of our study was to specify placental cell types which can be infected by HIV and thereby outline possible transmission routes.
We examined 12 formalin-lixed placentae of HIV-positive mothers (11 African, one Belgian) by in-situ hybridization with a 35S-labeled RNAprobe (at least three tissue sections) and immunostaining with anti-p24 antibody (at least five tissue sections). Negative controls consisted of three placentae of HIV-negative pregnancies. Positive controls were a lymph node with HIV-associated lymphadenopathy and a HIV-infected T-cell line. The histologi- cal findings were correlated to clinical data (medical history, CDC stage, course 01 pregnancy, fetal outcome).
Five placentae showed p24 positive Hofbauer cells. In two of them we found additionally positive signals in amniotic epithelium or chorion by in-situ hybridization indicating replicating virus. These two cases were the only ones with CDC stage IV (seven cases CDCI, three cases CDC III, two cases CDCIV). We did not find replicating virus in villous HoIbauer cells. Therefore the p24 positivity most likely represents non-replicating viral particles. Replicating virus containing cells in the chorion may be of maternal (via decidua) or fetal (via chorionic plate or amnion fluid) origin. Replicating virus in amniotic epithelium suggests secondary viral transmission in the membranes via infected amniotic fluid, probably indicating fetal infection. [Supported by BMFT (Nr. II-098-89).]