Adhesive and degradative properties of human placental cytotrophoblast cells in vitro.

Human fetal development depends on the embryo rapidly gaining access to the maternal circulation. The trophoblast cells that form the fetal portion of the human placenta have solved this problem by transiently exhibiting certain tumor-like properties. Thus, during early pregnancy fetal cytotrophoblast cells invade the uterus and its arterial network. This process peaks during the twelfth week of pregnancy and declines rapidly thereafter, suggesting that the highly specialized, invasive behavior of the cytotrophoblast cells is closely regulated. Since little is known about the actual mechanisms involved, we developed an isolation procedure for cytotrophoblasts from placentas of different gestational ages to study their adhesive and invasive properties in vitro. Cytotrophoblasts isolated from first, second, and third trimester human placentas were plated on the basement membrane-like extracellular matrix produced by the PF HR9 teratocarcinoma cell line. Cells from all trimesters expressed the calcium-dependent cell adhesion molecule cell-CAM 120/80 (E-cadherin) which, in the placenta, is specific for cytotrophoblasts. However, only the first trimester cytotrophoblast cells degraded the matrices on which they were cultured, leaving large gaps in the basement membrane substrates and releasing low molecular mass 3H-labeled matrix components into the medium. No similar degradative activity was observed when second or third trimester cytotrophoblast cells, first trimester human placental fibroblasts, or the human choriocarcinoma cell lines BeWo and JAR were cultured on radiolabeled matrices. To begin to understand the biochemical basis of this degradative behavior, the substrate gel technique was used to analyze the cell-associated and secreted proteinase activities expressed by early, mid, and late gestation cytotrophoblasts. Several gelatin-degrading proteinases were uniquely expressed by early gestation, invasive cytotrophoblasts, and all these activities could be abolished by inhibitors of metalloproteinases. By early second trimester, the time when cytotrophoblast invasion rapidly diminishes in vivo, the proteinase pattern of the cytotrophoblasts was identical to that of term, noninvasive cells. These results are the first evidence suggesting that specialized, temporally regulated metalloproteinases are involved in trophoblast invasion of the uterus. Since the cytotrophoblasts from first trimester and later gestation placentas maintain for several days the temporally regulated degradative behavior displayed in vivo, the short-term cytotrophoblast outgrowth culture system described here should be useful in studying some of the early events in human placen

Excretory urography as a screening method for abnormalities of the upper urinary tract in asymptomatic boys with undescended testicles.

Congenital dystopic testicles frequently occur jointly with abnormalities of the kidneys and the system of draining urinary ducts. A series of 100 asymptomatic boys has been studied by intravenous excretory urography after having undergone orchiopexy for retained testes. All children were clinically non-suspect and there was no history of urinary tract malformation. The investigations brought to light 7 major and 9 minor abnormalities. However, the authors do not recommend the use of intravenous urography as a routine procedure in all children with undescended testicles. The indications of the diagnostic procedure must be limited.

Nitro musk compounds genotoxic activity : Genotoxicity testing of nitro musks with the SOS-chromotest and the sister-chromatid exchange test.

Five nitro musk compounds are widely used as fragrance ingredients in perfumes, lotions and detergents; as food additives in cigarettes and fish baits, and in such technical products as herbicide formulations and explosives. Several studies identified nitro musk compounds in aquatic environment samples, human milk and fat samples as highly lipophilic and persistent bioaccumulating environmental pollutants. To examine the compounds for genotoxic activity, musk xylene (1-tert.-butyl-3, 5-dimethyl-2, 4, 6-trinitrobenzene), musk ketone (4-tert.-butyl-3, 5-dinitro-2, 6-dimethylacetophenone), musk ambrette (l-tert.-butyl-4-methyl-6-methoxy-3, 5-dinitrobenzene), musk moskene (l, 1, 3, 3, 5-pemamethyl-4, 6-di-nitroindane) and musk tibetene (1-tert.-butyl-3, 4, 5-trimethyl-2, 6-dinitrobenzene) were tested for SOS inducing potency in the SOS chromotest with E. coli PQ37 and for sister-chromatid exchange inducing activities in human lymphocytes in vitro both in the presence and absence of an exogenous metabolizing system from rat liver S9-Mix. Nitro musks revealed no genotoxicity either in the SOS chromotest with E. coli PQ37 or in the sister-chromatid exchange test with human lymphocytes.

[Asbestosis in the thoracic roentgen image]. / Die Asbestose im Thoraxröntgenbild.

Asbestos is a silicate fiber that may cause asbestosis 20-30 years after exposition. Asbestosis is characterized by pulmonary fibrosis, thickening of the pleura and calcified pleuraplaques. In addition, asbestosis may lead to bronchial carcinoma or mesothelioma. As patients are rarely referred to rule out asbestosis, and chest films are obtained for other clinical questions, it is important for the radiologist to recognize the typical plain film findings. These typical signs are illustrated in the following manuscript.

Antigenic requirements for stimulation and target cell recognition by immune and non-immune cytotoxic T lymphocytes.

The molecular requirements for recognition of antigen-modified cells by cytotoxic T lymphocyte precursors (CTLp) and their activated progeny, cytotoxic T lymphocytes (CTL), have been compared using haptenated stimulator and target cells. The antigen density requirements of T cell recognition by fluorescein-specific CTLp and CTL derived both from naive mice and from animals previously primed in vivo were determined. The cell surface hapten concentration required to stimulate CTLp cannot be distinguished from that required on target cells for lysis by their mature daughter CTL 5-7 days later. However, if the CTL (and their precursor CTLp) are derived from mice primed in vivo with hapten-conjugated cells, they require lower cell surface hapten densities for recognition than do the analogous T cell populations from naive animals. Thus, the maturation of CTLp into CTL during 5-7 days in vitro does not result in any functionally relevant change in the nature or density of antigen receptors on the surface of the T cell. This is in contrast to the apparent selection which occurs over longer time periods in vivo following priming.

Minimal Rev-response element for type 1 human immunodeficiency virus.

Rev protein regulates nuclear export of viral mRNAs that contain a 240-base RNA sequence termed the Rev-response element (RRE). We demonstrate that an 88-base truncated RRE encompassing a known Rev binding site can mediate Rev responsiveness in vivo. Two tandem copies of this mutant function as efficiently as the full-length RRE.

P-glycoprotein expression in high grade central osteosarcoma and normal bone cells. An immunohistochemical study.

One important mechanism by which multidrug resistance is mediated is the mdr1 gene product, P-glycoprotein (Pgp). Even though chemotherapy, in the treatment of high grade central osteosarcoma (hgc-OS), has led to dramatic improvements in survival rate, a certain percentage of patients still show only a poor response to chemotherapy. To further characterize a potential connection between Pgp and chemotherapy as well as the role of Pgp in tumorigenesis of osteosarcoma, we analyzed Pgp-expression in hcg-OS. Immunohistochemistry was performed on 68 hgc-OS samples from 58 patients using the monoclonal antibody JSB-1; in addition, Pgp-expression in normal bone cells was studied in 5 human epiphyseal growth plates. 70.5% of all cases stained positive for P-glycoprotein, while 29.5% of the cases were negative. Cases investigated after chemotherapy showed a higher incidence (82.9%) of positive P-glycoprotein immunostaining than cases prior to chemotherapy (64.4%). The Pgp-expression of 34 biopsies was compared with chemotherapy, as determined at the surgical specimen. In these cases, however, no correlation could be established between P-glycoprotein expression of the biopsy and the later response to chemotherapy. 48.4% of the cases with biopsies, initially positive for Pgp, showed a good response in the surgical specimen, while only 27.2% of Pgp-positive biopsies were later classified as non-responders. In the normally growing skeleton, positive immunostaining was detected in the area of mineralization of epiphyseal growth plates. Osteoclasts, hypertrophic chondrocytes, and cuboidal osteoblasts showed Pgp-expression, while there was a lack of Pgp in the majority of osteocytes and chondrocytes in the resting and proliferating zone. These data therefore suggest that P-glycoprotein expression in hgc-OS resembles, at least in part, the phenotype of active bone cells. These results may explain why P-glycoprotein, by using immunohistochemistry, in biopsies of osteosarcomas is insufficient to predict the response to chemotherapy.

[P-glycoprotein expression in osteosarcoma]. / P-Glykoproteinexpression beim Osteosarkom.

One of the mechanisms by which multidrug resistance is mediated, is the mdr1 gene product, P-glycooprotein. Immunohistochemistry was performed for 63 osteosarcomas of 54 patients to investigate P-glycoprotein expression using the monoclonal antibody JSB-1. Most of the patients were children or adolescents who had received treatment under the framework of the Cooperative Osteosarcoma Study Group. In addition P-glycoprotein expression was assayed in five growth plates. Of all cases 68.5% stained positive for P-glycoprotein. Cases that had received chemotherapy showed a higher incidence (80.9%) of positive P-glycoprotein immunostaining than cases that had not received chemotherapy (66.6%). No relation could be established between P-glycoprotein expression and the response to chemotherapy, since the majority of P-glycoprotein positive biopsies showed a good response in the surgical specimen after chemotherapy. Furthermore, 42.9% of P-glycoprotein negative biopsies were classified as non-responders in the later surgical specimen. In addition to P-glycoprotein expression in osteosarcomas positive immunostaining was also detected in osteoblasts, osteocytes, osteoclasts as well as in some chondroblasts. The results indicate that P-glycoprotein expression in osteosarcomas also exists prior to chemotherapy and resembles the phenotype of normal bone tissue. However, the determination of P-glycoprotein by using immunohistochemistry in biopsies of osteosarcomas cannot predict the response to chemotherapy.