Placental Isolates Research Articles

Plasmodium falciparum: Adhesion of Placental Isolates Modulated by the Sulfation Characteristics of the Glycosaminoglycan Receptor

Fried, M., Lauder, R. M., and Duffy, P. E. 2000. Plasmodium falciparum: Adhesion of placental isolates modulated by the sulfation characteristics of the glycosaminoglycan receptor. Experimental Parasitology95, 75–78.

Plasmodium falciparum rosette formation is uncommon in isolates from pregnant women.

We examined the formation of Plasmodium falciparum erythrocyte rosettes using parasite isolates from placental or peripheral blood of pregnant Malawian women and from peripheral blood of children. Five of 23 placental isolates, 23 of 38 maternal peripheral isolates, and 136 of 139 child peripheral isolates formed rosettes. Placental isolates formed fewer rosettes than maternal isolates (range, 0 to 7. 5% versus 0 to 33.5%; P = 0.002), and both formed fewer rosettes than isolates cultured from children (range, 0 to 56%; P < 0.0001). Rosette formation is common in infections of children but uncommon in pregnancy and rarely detected in placental isolates.

Studies of Mesenchymal Cells from 1st Trimester Human Placenta: Expression of Cytokeratin Outside the Trophoblast Lineage

A fibroblast cell strain that expressed cytokeratins 8 and 18 was isolated from explanted first trimester placenta. Its properties were consistent with an origin in the villous fibroblast–myofibroblast lineage, including expression of vimentin, smooth muscle α-actin and fibroblast surface protein. The cells grew rapidly in vitro, and exhibited tightly aligned bipolar morphology at confluence, absence of multi-nucleated cells, lack of secreted chorionic gonadotrophin, and absence of HLA G, placental alkaline phosphatase and pregnancy-specific beta-1 glycoprotein (SP1). On these criteria it was concluded they were not trophoblasts. On the basis of their morphology, cytokeratin expression and absence of CD34 and endoglin it was concluded they were not endothelial cells. They lacked desmin and smooth muscle myosin and so were not vascular smooth muscle cells. Further mesenchymal cell isolates were studied to determine the generality of these findings. Phenotypic heterogeneity was a consistent characteristic, but cytokeratin-positive cells were always present both in first trimester and term strains. Desmin was absent from almost all the cells isolated using the protocols employed, despite its occurrence in a significant subpopulation of cells in the villous stroma. Cytokeratins 8 and 18 can be observed in the stromal compartment of both first trimester and term placental villi. Cytokeratin has hitherto been regarded as a highly reliable marker for cells of the trophoblast lineage in vitro. These observations suggest that care should be taken in characterization of placental cell isolates; trophoblasts should be identified by the presence of cytokeratin 7 in preference to cytokeratin 8/18. The functional significance of cytokeratin expression in placental mesenchymal cells remains to be established.

Ampicillin susceptibilities of vaginal and placental isolates of group B streptococcus and Escherichia coli obtained between 1992 and 1994.

Vaginal group B streptococcus (GBS) and Escherichia coli isolates were tested for their susceptibilities to ampicillin. All 414 GBS isolates tested were susceptible to ampicillin; the MIC at which 90% of the isolates were inhibited (MIC90) was 0.125 microg/ml, and the range was 0.06 to 0.25 microg/ml. The MIC50 for the 342 E. coli isolates tested was 4.0 microg/ml, and 27% were resistant to ampicillin.

Novel appearance of placental nuclear monoamine oxidase: Biochemical and histochemical evidence for hyperserotonomic state in preeclampsia-eclampsia

OBJECTIVE: The aim of this study was to explore the relevance of placental monoamine oxidase at the subcellular level in the etiology of the hyperserotonomic state in preeclampsia-eclampsia. STUDY DESIGN: The study was conducted on placentas from 20 normal pregnant women and 25 women with varied severity of preeclampsia-eclampsia. Placental serotonin and subcellular monoamine oxidase activity were determined. Histochemical localization of monoamine oxidase was done in placental sections and cell isolates. RESULTS: Placental serotonin increases with severity ( r systolic 0.84, r diastolic 0.83) and monoamine oxidase decreases ( r systolic 0.86, r diastolic 0.79). Placental monoamine oxidase showed marked changes in preeclampsia-eclampsia. Histochemical localization of monoamine oxidase showed diffused low activity evenly throughout the cytoplasm and nucleus of the syncytiotrophoblastic cells in preeclampsia-eclampsia; in contrast, normal placenta showed high activity in the cytoplasm without any activity in the nucleus of syncytiotrophoblastic cells. Detection of monoamine oxidase activity in nuclei of the placenta in preeclampsia-eclampsia is a novel finding. Monoamine oxidase activity at the subcellular level further strengthens this observation. A severity-dependent decrease was present in the nuclei of placentas with preeclampsia-eclampsia. The use of specific substrates and inhibitors revealed the presence of monoamine oxidase in mitochondria and nucleus. CONCLUSION: The study delineates an impaired catabolism of placental serotonin in preeclampsia-eclampsia. The novel appearance of monoamine oxidase in nuclei in proximity to its normal site and low activity resulting in a hyperserotonomic state may lead to preeclampsia-eclampsia. (Am J Obstet Gynecol 1996;175:1543-50.)

Retroviral crossreactivity of trophoblast subpopulations within human placental cell isolates

Retroviral crossreactivity of trophoblast subpopulations within human placental cell isolates

Ultrastructural characterization of endogenous retroviral particles isolated from normal human placentas.

Human placental endogenous retroviral (ERV) particle isolates were investigated by ultrastructural evaluation. Although retrovirus-like structures in normal human placental tissue sections have been described, the precise nature of these particles has not previously been defined. By direct electron microscopic (EM) observation of placental ERV isolates that display retroviral reverse transcriptase (RTase) activity and a buoyant density consistent with type-C retroviruses (1.17 g/ml on sucrose), we have shown these to contain particles with characteristic retroviral ultrastructural features. Samples were stained with 1.0% phosphotungstic acid (PTA), 0.5% uranyl acetate (UA), and low-angle-shadowed with platinum/palladium. Isolated placental ERV particles have an apparent diameter of approximately 120 nm, are membrane-bound with a short surface fringe, and contain capsid particles (about 90 nm in diameter) within an internal matrix structure. These observations support the view that human placental cells normally express ERV particles.

Phenotypic characteristics of lymphocyte populations isolated from middle gestation human placenta

In order to characterize the phenotypic composition of populations of lymphoid cells in maternal and fetal tissues during the period of middle gestation, mononuclear cells were isolated from maternal peripheral blood, fetal spleen, fetal thymus and placenta of 18–24 week pregnancies. Peripheral blood and placental isolates were stained for a number of lymphoid cell markers by indirect immunofluorescence and analyzed by flow cytometry. Studies were performed on both freshly isolated mononuclear cell preparations and in vitro cultured cells after selective expansion in interleukin 2 (IL2). Fresh placental mononuclear cell isolates were an average 20% CD3 +; their CD4/CD8 ratios varied among individuals. An average of 68% of the lymphocytes isolated from maternal peripheral blood were CD3 +. Placental and maternal peripheral blood isolates had comparable percentages of CD16 + and CD20 + cells, while CD56 + cells were present at significantly greater numbers in the lymphocyte compartment of placenta (17%) than in peripheral blood (3%; P < 0.01). Lymphocyte isolates were expanded by culture with IL2 and PHA and stained to determine if propagated lymphocyte populations are representative of initial isolates. Expansion of all lymphocyte isolates favored CD3 phenotypes and CD8 phenotypes. Compared to expanded placenta-derived populations, expanded peripheral blood lymphocytes were similar with regard to percentages of all phenotypes except γ/δT cells which represented more of placental lymphocytes (10%) than peripheral lymphocytes (5%; P < 0.01). Surface HLA typing determined propagated placenta-derived lymphocytes to be of maternal and not fetal origin. In vitro propagation of placental mononuclear cell isolates may therefore provide populations of maternal CD3 + lymphocytes for assessment of function and specificity.

Immunolocalization of antioxidant enzymes and isozymes of glutathione S-transferase in normal rat lung.

Polyclonal antisera to manganese and copper-zinc superoxide dismutases, catalase, glutathione peroxidase (GPx), and isozymes of glutathione S-transferase (liver and placental isolates, GST-L and GST-P, respectively) were used to localize these enzymes in normal rat lung by immunostaining. Light-microscopic results, using an immunoperoxidase technique, were expanded on by electron-microscopic immunogold localization. The findings were consistent with previous biochemical work. However, both GPx and GST-P were predominantly localized to extracellular connective tissue of the lung. These findings demonstrate the basal antioxidant enzyme phenotypes for parenchymal lung tissue at light- and electron-microscopic levels. Significant components of enzymatic defense to oxidant stress are heterogeneously distributed throughout rat lung tissue including both epithelial cell surfaces and the extracellular matrix.

Molecular cloning of AMP deaminase isoform L. Sequence and bacterial expression of human AMPD2 cDNA.

Human AMPD2 cDNA clones have been isolated from T-lymphoblast and placental lambda gt11 libraries utilizing a previously cloned rat partial AMPD2 cDNA as the probe. Alignment analysis of all cDNA clones indicates the presence of intervening sequences in several placental isolates. This has been confirmed by sequencing human AMPD2 genomic clones. Intervening sequences can be removed from the cDNA clones by restriction with endonucleases at unique sites within the proposed open reading frame. This results in a 3292-base pair cDNA proposed to contain the entire AMPD2 open reading frame, which would encode a 760-amino acid polypeptide with a predicted subunit molecular mass of 88.1 kDa. Nucleotide and predicted amino acid comparisons with the 264 base pairs of proposed coding sequences in the rat AMPD2 cDNA demonstrate 91% similarity and identity, respectively. A comparison of the predicted human AMPD1 and AMPD2 polypeptides demonstrates homology in their C-terminal domains. Included in this region is the conserved motif, SLSTDDP, proposed to be part of the catalytic site of all AMP deaminases. In contrast, the predicted N-terminal domains of the human AMPD1 and AMPD2 polypeptides are unique. When placed in a prokaryotic expression vector, the human AMPD2 cDNA expresses AMP deaminase activity which can be precipitated with polyclonal antisera specific for isoform L.

Antigenic and morphological differentiation of placental and intestinal isolates of Chlamydia psittaci of ovine origin

Ewe placental and lamb intestinal isolates of Chlamydia psittaci recovered from flocks affected with ovine enzootic abortion were examined by inclusion morphology, indirect immunofluorescence (IIF) and immunoblot analysis. Chlamydiae recovered from the faeces of sheep from two flocks free of clinical disease were also examined. In cell culture ovine abortion (OA) and intestinal isolates were distinguishable by inclusion development and morphology. Similarly, in two-way IIF tests with one week mouse antisera isolates fell into two distinct groups: abortion or intestinal. Immunoblotting with convalescent sheep abortion antiserum identified 30 out of at least 40 silver staining polypeptides as antigenic both in OA and intestinal isolates. The serum produced a similar reaction pattern to the resolved proteins of each OA isolate, indicating a higher degree of antigenic conservation among these isolates. Considerable cross reactivity between the OA and intestinal isolates was identified, but the serum also showed apparent molecular weight differences between antigens of the two types in the 87–116 kDa, 38–44 kDa and 26–28 kDa regions. Furthermore, the immunoblotting analysis revealed heterogeneity among the intestinal isolates, particularly in antigens between 87–116 kDa and 38–44 kDa.

Detection and Localisation of Sialic Acid inGardnerella vaginalis, Mobiluncusspp., and Other Vaginal Microorganisms

Sialic acid, n-acetylneuraminic acid, is found in the cell wall of all serotypes of group B Streptococcus and Escherichia coli serotypes K1 and K3. It has been most strongly associated with those strains which cause neonatal meningitis. The purpose of this study is to report the presence of sialic acid in some genital tract bacteria. Bacteria were grown to log phase. Mild-acid hydrolysis of whole organisms released a compound which reacted positively in the periodatethiobarbituric acid (PTA) assay, a colorimetric assay detecting n-acetylneuraminic acid. Surface localisation of sialic acid was supported by the observation of bacterial agglutination with an affinity-purified lectin ( Limulus polyphemus agglutinin) which binds sialic acid residues. Four vaginal isolates of Mobiluncus curtisii and three vaginal isolates of Mobiluncus mulieris strains tested contained a level of sialic acid equivalent to that of the group B Streptococcus control by PTA assay. Four Gardnerella vaginalis strains (three vaginal and two placental isolates) were positive for sialic acid by PTA assay. Nine clinical vaginal isolates of Peptostreptococcus : P. anaerobius (2), P. asaccharolyticus (3), P. magnus (2) and P. tetradius (2) were negative for sialic acid. Two clinical vaginal isolates of Enterococcus faecalis and four diphtheroid isolates were also negative. Eleven clinical vaginal isolates of viridans streptococci including S. intermedius (5) , S. constellatus (4), and S. acidominimus (2) were negative for sialic acid. One of three clinical vaginal isolates of S. acidominimus , one of four clinical vaginal isolates of coagulase negative staphylococci and two of seven clinical vaginal isolates of lactobacilli tested positive for low levels of sialic acid. All strains in which sialic acid was detected by PTA assay showed surface localisation by lectin agglutination. The presence of sialic acid on the surface of Gardnerella and Mobiluncus , two organisms associated with bacterial vaginosis, may be associated with their capacity to colonise or infect the genital tract. Keywords: Sialic acid; Mobiluncus spp.; Gardnerella vaginalis ; vaginal bacteria.