Vocal fold paresis of Charcot-Marie-Tooth disease

No cohesive overview of vocal fold abnormalities associated with Charcot-Marie-Tooth disease (CMT) has been presented in the literature. This study examines a patient in depth and compares the findings with those of published reports to characterize the features of vocal fold paresis in CMT. The affected patient was investigated with nerve conduction testing, laryngeal electromyography, endoscopy, and laryngeal sensory testing. Ten published cases were reviewed for similarities and differences. Vocal fold paresis has been observed in 11 CMT patients ranging in age from 8 to 80 years. Two cases have occurred in the context of CMT type 1, and 9 in CMT type 2. Seven of the 11 cases (64%) were clearly bilateral; only 2 of the 7 cases (29%) required tracheotomy, and both were in children. The electromyographic findings were typical of reinnervation. Sensory findings were present, but did not represent significant disability in the 1 patient so studied. We conclude that CMT does not spare the cranial nerves, as has been previously thought. Furthermore, vocal fold paresis is not restricted to CMT type 2 and should not be considered a hallmark of that category. The available evidence suggests that the neural deficit evolves gradually, may exhibit partial recovery, and often escapes notice for a time. Vocal fold abnormalities are most often bilateral. Because the deficit is generally well tolerated in adults, many cases have probably been overlooked, and no conclusion regarding incidence is possible. Nevertheless, the potential for airway compromise exists, especially in children. Respiratory complaints of CMT patients should be thoroughly investigated.

Apoptosis and syncytial fusion in human placental trophoblast and skeletal muscle

Skeletal muscle fibers and placental villous trophoblast are the main representatives of syncytia in the human. Both syncytia are derived from fusion of mononucleated stem cells, show a high degree of differentiation, and have lost their generative potency. Consequently, for their growth both depend on fusion of additional stem cells. There is evidence that syncytial fusion is directly or indirectly related to apoptotic events: As early as in the differentiated stages of the mononucleated stem cells, initiation stages of the apoptosis cascade have been observed. After syncytial fusion progression of the cascade is retarded or blocked by a variety of mechanisms. In this review we emphasize the links between apoptosis cascade, differentiation pathways and syncytial fusion. It needs to be elucidated whether these processes simply take place in parallel, both temporally and spatially, or whether there are causal connections between apoptosis cascade and syncytial fusion. Based on recent data obtained for placental villous trophoblast, it is tempting to speculate that early molecular mechanisms of the apoptosis cascade are involved in differentiation and syncytial fusion. Data obtained in skeletal muscles support this assumption and reveal a considerable degree of homology in genesis, maintenance and turnover of both tissues.

A longitudinal study of quantitative uterine blood flow with the use of color power angiography in appropriate for gestational age pregnancies

OBJECTIVE

The purpose of this study was to examine longitudinally changes in quantified blood volume flow in the uterine arteries during pregnancy with the use of color power angiography.

STUDY DESIGN

Color power angiography was used to quantify volume flow in the uterine arteries of 57 women with singleton uncomplicated pregnancies between 20 and 38 weeks' gestation. Comparisons were made between blood flow in the 2 arteries in relation to the location of the placenta. Linear regression models were used to estimate gestational age derived volumetric changes in these vessels.

RESULTS

The diameter of the uterine arteries increased from 2.6 mm (SD, 0.2 mm) at 20 weeks to 4.8 mm (SD, 0.7 mm) at 38 weeks of gestation. The total uterine artery blood volume flow increased from 513 mL/min (SD, 127 mL/min) at 20 weeks to 970 mL/min (SD, 193 mL/min) at 38 weeks. The rate of increase was maximum between 20 and 24 weeks (39 mL/min per week). The laterality of the placenta significantly affected the diameter and blood volume flow in each uterine artery. The diameters on the ipsilateral side were significantly greater (by 10.8% +/- 2.4%) than the diameters on the contralateral side at all gestations (P < .05). Similarly, blood volume flow was significantly greater (by 17.8% +/- 2.2%) on the ipsilateral side at all gestations (P < .05). There were, however, no statistically significant differences between the vessel diameters and blood volume flow in those cases in which the placenta was central. Total uterine artery volume flow per kilogram of estimated fetal weight decreased from 1544 mL/kg per minute at 20 weeks to 296 mL/kg per minute at 38 weeks of gestation.

CONCLUSION

Total quantified uterine artery blood volume flow increases while blood flow per kilogram of fetal weight decreases with gestation. Blood volume flow in the ipsilateral artery to the placenta was significantly higher than that in the contralateral artery. Calculating total uterine artery volume flow by doubling the blood flow from 1 artery (as was previously done) may therefore either result in an over or underestimation, depending on the relationship between the vessel and the laterality of the placenta. Color power angiography is a simple noninvasive tool for determining uterine artery blood volume flow.

Macrophage-induced apoptosis limits endovascular trophoblast invasion in the uterine wall of preeclamptic women

Impaired invasion of uteroplacental arteries by extravillous trophoblast cells is a key pathogenic mechanism of preeclampsia. We previously demonstrated that reduced trophoblast invasion into uteroplacental spiral arteries was associated with an excess of macrophages in and around these arteries. To explore the significance of these observations, we correlated the extent of extravillous trophoblast apoptosis in placental bed biopsy specimens with macrophage distribution and studied the effect of macrophages upon trophoblast apoptosis in vitro. Extravillous trophoblast hybrid cells were cocultured with activated macrophages exposed to exogenous tumor necrosis factor alpha (TNFalpha), anti-tumor necrosis factor receptor I (TNF-RI), and tryptophan depletion, and the rates of trophoblast apoptosis were measured. Extravillous trophoblast hybrid cells showed increased rates of apoptosis following exposure to exogenous TNFalpha, with tryptophan depletion, and when cocultured with activated macrophages. The proapoptotic effects of macrophages in vitro were completely inhibited only by simultaneous addition of tryptophan and anti-TNF-RI. Our data indicate that macrophages, residing in excess in the placental bed of preeclamptic women, are able to limit extravillous trophoblast invasion of spiral arterial segments through apoptosis mediated by the combination of TNFalpha secretion and tryptophan depletion. The mechanisms by which macrophages are activated and recruited to the placental bed are presently unknown but are likely central to the pathogenesis of preeclampsia.

Human trophoblast contains an intracellular protein reactive with an antibody against CD133--a novel marker for trophoblast

CD133 is a protein expressed on the cell membrane of a subfraction of haematopoietic stem and progenitor cells, as well as on some epithelial cells. Previously available antibodies against CD133 recognized only the glycosylated protein, localized to membrane protrusions or microvilli. Due to this, immature intracellular stages of the CD133 protein could not be visualized using these antibodies. We describe reactivity of a commercially available antibody against CD133, called AC133-2, with an intracellular protein in trophoblast. Both villous and extravillous cytotrophoblast, as well as syncytiotrophoblast were stained by AC133-2 in cryostat sections of first trimester and term placenta. Villous stroma was not stained. AC133-2 reactivity was seen in methanol-fixed primary trophoblast cells and trophoblast-derived cell lines, and was coexpressed with cytokeratin-7. CD133 messenger RNA was present in trophoblast and trophoblast-derived cell lines, but also in cells not displaying any reactivity with CD133 antibodies. AC133-2 recognized a 55-60 kDa protein on Western blots of cell extracts including trophoblast. The exact nature of this protein is not yet understood. However, AC133-2 is applicable as a positive marker for the characterization of all subtypes of trophoblast and for trophoblast cell lines.

Characterization of trophoblast cell isolations by a modified flow cytometry assay

The purity of isolated trophoblast cells is an important checkpoint in in vitro studies on the human placenta. Maintaining viability of primary cells for a prolonged period, or achieving cell proliferation in primary cell cultures, is often a matter of concern. In this paper we present a method for characterizing the purity of isolated trophoblast cells based on the expression of cytoskeletal proteins, as well as for assessing their cell cycle status, by flow cytometry. We show that after a simple permeabilization and fixation step in 70 per cent methanol, staining for cytokeratin 7 and vimentin could discriminate between trophoblast cells and contaminating populations. The method was applicable to trophoblast cells both from villous and extravillous origin. By staining the proliferation-related antigen Ki-67 and DNA, information was gained about the cell cycle status and viability of freshly isolated and cultured villous trophoblast cells. This method may help to quickly and quantitatively characterize preparations of isolated trophoblast, as well as to search for culture conditions favouring long-term survival and proliferation.

Expression of a cytokeratin 18 neo-epitope is a specific marker for trophoblast apoptosis in human placenta

In epithelial cells the caspase-mediated cleavage of cytokeratin 18 during apoptosis leads to the formation of a specific neo-epitope, recognized by the antibody M30. To test whether this antibody can be used as a specific marker for apoptotic trophoblast, we have stained serial sections of villi and junctional zone of first and third trimester human placenta with antibodies against cytokeratins 7 and 18, and against active caspase 3, with M30 and with the TUNEL reaction. Comparison of M30 immunoreactivities with TUNEL positivity and immunoreactivities for cytokeratins 7 and 18 clearly demonstrates that M30 specifically labels late apoptotic trophoblast cells. This finding is supported by the fact that in trophoblast, M30 immunoreactivities largely overlap with those for active caspase 3. As compared to the TUNEL test, the M30 immune reaction appears to be a highly reproducible marker for apoptotic trophoblast. This antibody stains a larger number of cells within the apoptosis cascade as compared to the TUNEL reaction, since cytokeratin 18 cleavage starts earlier than cleavage of DNA and since endonuclease activation can be bypassed in some trophoblast cells. The data suggest that M30 is superior to the TUNEL reaction as a marker for the detection of trophoblast apoptosis since it is easier to handle, more specific for apoptosis and less prone to artifacts.

A teaching videotape for the assessment of essential tremor

Teaching videotapes, developed to aid in the evaluation of several movement disorders, have not been used in essential tremor research. As part of the Washington Heights-Inwood Genetic Study of Essential Tremor (WHIGET), we developed a reliable and valid tremor rating scale. Because this rating scale is currently being used by investigators at other centers, we developed a teaching videotape to aid in the consistent application of this scale.

OBJECTIVE

To develop a teaching videotape for a revised version of the WHIGET Tremor Rating Scale and to assess the interrater agreement among raters who used this videotape to rate tremor.

METHODS

The revised WHIGET Tremor Rating Scale was used to rate action tremor from 0 to 4 during six tests: arm extension, pouring, drinking, using a spoon, finger-to-nose, and drawing spirals. A 22-minute teaching videotape was developed that includes a 29-item educational section and a self-assessment section consisting of 20 examples of tremor ratings chosen by the two WHIGET study neurologists. Eight raters, including senior movement disorder specialists, movement disorder fellows, general neurologists, and a movement disorder nurse practitioner, independently viewed the videotape and rated tremor during the self-assessment section. Interobserver reliability was assessed with weighted kappa statistics (kappa(w)).

RESULTS

Eight raters each rated 20 items (160 ratings total). Total kappa(w) was 0.97 (nearly perfect agreement). Interrater reliability was as follows: kappa(w) = 0.99 (movement disorder specialists), kappa(w) = 0.98 (movement disorder fellows), and kappa(w) = 0.97 (general neurologists); all kappa(w) were nearly perfect.

CONCLUSIONS

This teaching videotape may be used to improve the uniform application of the revised WHIGET Tremor Rating Scale by raters with various levels of experience in movement disorders.

Cognitive consequences and central nervous system injury following treatment for childhood leukemia

OBJECTIVES

To determine the relationship between membrane damage and intellectual and academic abilities in children with acute lymphoblastic leukemia (ALL) and pilot test a math intervention for children with ALL who were affected.

DATA SOURCES

Research studies and review articles.

CONCLUSIONS

Despite the prophylactic central nervous system (CNS) treatment for long-term disease-free survival, many children with ALL subsequently experience declines in intellectual and academic skills.

IMPLICATIONS FOR NURSING PRACTICE

Improving academic abilities in children who have received CNS treatment is of high priority and may have longlasting implications on quality of life.

High level of cholesterol increases coronary vasomotor tone during exercise

BACKGROUND

Coronary vasomotor tone plays an important role in the regulation of myocardial perfusion and influences ischemic threshold significantly. Endothelial dysfunction occurs in the presence of coronary risk factors and is closely linked to the development of atherosclerosis affecting myocardial perfusion and decreasing ischemic threshold.

OBJECTIVE

To study the effect of hypercholesterolemia on coronary vasomotor tone in normal and stenotic coronary arteries at rest and during exercise.

PATIENTS AND METHODS

In total 48 patients were included in the present analysis. Patients were divided into two groups according to the actual levels of serum cholesterol: 18 patients had normal (mean 181 +/- 28 mg%; group 1) and 30 had elevated (mean 263 +/- 46 mg%; group 2) levels of serum cholesterol according to the 4S criteria with a cutoff level of 213 mg% (5.5 mmol/l). Coronary vasomotor tone at rest and during supine bicycle exercise was calculated by dividing mean aortic pressure by radius of coronary vessel obtained using biplanar quantitative coronary angiography. A normal as well as a stenotic vessel segment in each patient were studied.

RESULTS

Normal vessel segments in patients with normal levels of cholesterol (group 1) exhibited no exercise-induced change in coronary vascular tone (+3%, NS), whereas a significant increase in tone (+24%, P < 0.01 versus rest) occurred in those with high levels of cholesterol (group 2). In contrast, stenotic segments in members of both groups exhibited an increase in vascular tone irrespective of the actual level of serum cholesterol.

CONCLUSIONS

Hypercholesterolemia causes a pathologic increase in coronary vasomotor tone of angiographically normal vessel segments during exercise. A similar pathologic response occurs in stenotic arteries, but this is independent of the actual level of serum cholesterol. These findings suggest that hypercholesterolemia influences vasomotor tone of the nonstenosed coronary arteries in patients with coronary artery disease probably through the occurrence of endothelial dysfunction.

Development of the placental villous tree and its consequences for fetal growth

Co-ordinated development of the fetal villous tree of the placenta is necessary for continued fetal growth and well-being. Before fetal viability, blood vessel development within the developing immature intermediate villi (IIV) is characterized by branching angiogenesis, such that the placenta expands to produce 10-16 generations of stem villi. Once fetal viability is attained, a developmental switch occurs to form large numbers of gas-exchanging terminal villi (TV) by non-branching angiogenesis in mature intermediate villi (MIV). Several growth factors, including vascular endothelial growth factor (VEGF), placenta growth factor (PlGF), angiopoietins, and angiostatins are produced within the villi and act locally, via their receptors, to control angiogenesis. Their relative contributions to placental vascular development are not fully understood at the present time. Severe early-onset intrauterine growth restriction (IUGR) is characterized by absent/reversed end-diastolic flow velocity (ARED) in the umbilical arteries, leading to fetal hypoxia, acidosis and a substantial rise in perinatal mortality and morbidity. The placentas from such cases show a deficit in peripheral villous development, which may be perpetuated by the effects of oxygen (delivered by maternal blood into the intervillous space) upon VEGF-directed angiogenesis, the so-called 'placental hyperoxia' theory of villous maldevelopment. Trophoblast apoptosis is a significant feature of early-onset IUGR and may explain poor flow-independent transfer of nutrients to the fetus. Finally, since transgenic mouse studies highlight the importance of trophoblast-derived transcription factors for placental villous (labyrinth) development, it is possible that the villous trophoblast controls the orderly development of the underlying mesoderm and blood vessels into the fetal villi.

Distensible transtrophoblastic channels in the rat placenta

Paracellular pathways in the haemotrichorial placenta of the rat were studied by electron microscopy using lanthanum hydroxide as an electron dense marker. Near term placentae were dually perfused in situ, adding lanthanum to the fetal perfusate. In some placentae outflow pressure on the fetal side was elevated (between 10 and 25 cm H(2)O) to promote filtration of fluid in a fetomaternal direction. Under normal pressure conditions lanthanum particles lined the subendothelial spaces and tubular structures in the inner, syncytial layer of trophoblast. Further penetration of lanthanum into the tubules was blocked by coarse lanthanum aggregates. Elevated fetal hydrostatic pressure resulted in a fluid shift across the placenta (filtration rate 50+/-16 per cent of fetal arterial inflow rate), distending the tubules in the inner trophoblast layer. Lanthanum particles gradually appeared in tubular structures in the middle (syncytial) layer and in the lateral intercellular spaces in the outer (cellular) layer. Finally lanthanum reached the maternal surface of the trophoblast. These pressure effects were only partially reversible. When the fetal pressure was returned to control values, some distension of the tubules persisted and the entire length of the paracellular pathways remained accessible to lanthanum. It is concluded that the placental barrier in the rat contains pressure dependent paracellular pathways connecting the maternal and fetal extracellular compartments.

Villous sprouting: fundamental mechanisms of human placental development

There is increasing evidence that maldevelopment of the placental villous tree can play an important role in the pathogenesis of various pregnancy diseases. In this review we present the most recent advances of cellular and molecular mechanisms involved in the early formation of chorionic villi. In particular we focus our attention on the structural events during early villous sprouting leading to the formation of the mesenchymal villi which are the forerunners of all other villous types, i.e. immature intermediate villi, stem villi, mature intermediate villi and terminal villi. Early villous sprouting starts as 'hot spots' which are circumscribed areas consisting of highly proliferating cytotrophoblastic and stromal cells. The post-proliferative cytotrophoblastic cells fuse with the overlying syncytium leading to the formation of the trophoblastic sprouts. When villous mesenchyme invades the trophoblastic sprouts, the latter are transformed into villous sprouts. The vascularization of the villous sprouts leads to the formation of the mesenchymal villi, the most basic villous type. This process is repeated throughout pregnancy. We analyse the influence of various extracellular matrix molecules, e.g. tenascin and hyaluronic acid, on the formation of hot spots and mesenchymal villi as well as the transformation of the latter in other villous types. We present a critical survey on the data on vessel formation related to villous sprouting and morphogenesis of mesenchymal villi as well as the expression of various angiogenic factors and their receptors.

Endothelin A and B receptors change their expression levels during development of human placental villi

Endothelin receptors have recently been found in non-vascular tissues including the human placenta. The present study investigated developmental changes in location and expression levels of endothelin A and B receptors (ETA-R, ETB-R) in human placentae and isolated trophoblast by comparing first and third trimester tissues. In the first trimester all cells and tissues were immunolabelled for ETA-R and ETB-R, whereas in third trimester placentae the syncytiotrophoblast (ETA-R, ETB-R) and macrophages (ETA-R) were unstained. Immunoblotting for both receptors revealed up to three bands at 33-35, 50 and 75 kDa, respectively, which were differentially present in the first and third trimester. Pre-adsorption of antibodies with oligopeptides used for antigen-generation weakened the immunoreactions. ETA-R protein levels decreased (P< 0.05) in total villous tissue and isolated trophoblast, whereas ETB-R was unchanged. ETB-R transcripts (RT-PCR) prevailed in both stages and tissues, but in contrast to the protein levels its preponderance decreased from first trimester to term in villous tissue (P< 0.01), because of a four to five-fold increase in ETA-R and only a two-fold (P< 0.05) increase in ETB-R mRNA levels (P< 0.01). We conclude that ET receptor location, intracellular processing and expression levels in human villous tissue change between the first and third trimester. This may reflect changing functions of ET-1 during placental development.

Pregnancy-induced de-differentiation of media smooth muscle cells in uteroplacental arteries of the guinea pig is reversible after delivery

The majority media of smooth muscle cells of uteroplacental arteries of the guinea pig is not destroyed during trophoblast invasion. Rather, most of these cells de-differentiate during pregnancy-induced arterial dilatation, forming a population of mesenchyme-like myoblasts ready to reconstitute the media after birth. We have studied the re-differentiation of these cells after delivery by means of transmission electron microscopy and immunohistochemistry using antibodies against a panel of cytoskeletal proteins. The data reveal that post partum re-differentiation of the media myoblasts starts immediately after birth where some of the invasive trophoblast cells are still present. The process of re-differentiation is completed at day 8 after parturition. Post partum re-differentiation can be subdivided into two steps: until day 5 after parturition, the central parts of the media are reconstituted out of the reservoir of vimentin-positive myoblasts by stepwise acquisition of desmin, alpha-smooth muscle actin, gamma-smooth muscle actin and smooth muscle myosin. Only thereafter the same re-differentiation takes place in the peripheral parts of the media. On the ultrastructural level immunohistochemical re-expression of cytoskeletal proteins is accompanied by reconstitution of the intracellular contractile apparatus. The data support our earlier notion that the majority of media smooth muscle cells in the guinea pig uterus does not degenerate during trophoblast-invasion but rather de-differentiate temporarily.

[Trophoblast invasion in pre-eclampsia]

It is generally accepted that insufficient invasion of trophoblast cells into the myometrial portions of the spiral arteries is thought to play a crucial role in the development of preeclampsia. As a consequence, uteroplacental vessels fail to undergo adaptive changes which are imperative to provide a sufficient blood supply to the placenta. Consecutive placental hypoxia is supposed to cause secretion/shedding of still unidentified placental metabolites resulting in different forms of pregnancy-induced hypertension. This review presents published data concerning the causes of insufficient trophoblast invasion in preeclampsia. Expression of HLA-G by extravillous trophoblast cells seems to be altered, resulting in activation of the maternal immune system. The pattern of integrin expression as well as the secretion of proteases is reported to be disturbed, which could lead to a reduced invasive potential of the trophoblast cells. Recent data indicate a pathophysiological role of NK-cells and macrophages in the altered trophoblast invasion. Also angiotensinogen Thr235 polymorphism seems to alter early physiologic changes in spiral arteries. In summary, preeclampsia seems to be induced by a multifactorial disturbance of trophoblast invasiveness which is characterized by reduced invasiveness of the trophoblast cells themselves and by an activated maternal immune response blocking the invasion by the semiallogenic trophoblast.

Cell-cell-communication during placental development and possible implications for trophoblast proliferation and differentiation

Since direct cell-cell-communication plays a crucial role in the coordination of proliferation and differentiation processes during development we have focused on the expression patterns of gap junctions and their functional implication in the human placenta. The gap junction protein connexin40 (Cx40) is expressed in the proximal extravillous trophoblast of cell islands and columns. In accordance with these observations, isolated trophoblast cells from first and second trimester placentae and choriocarcinoma cells (Jeg-3) reveal Cx40 expression. This channel is not only characteristic of the trophoblast cells along the invasive pathway but also of endothelial cells. To elucidate the functional role of this channel for proliferation and invasion, the non-coupled Jeg-3 cells have been transfected with Cx26, Cx40 and Cx43, respectively. In contrast to Cx40, the Cx26 channel was more potent in reducing proliferation and inducing differentiation indicated by hCG-beta secretion. Using the nude mouse model to study invasion properties of choriocarcinoma cells, we demonstrated that malignant trophoblast cells were able to invade host vessels and to replace endothelial cells. Upregulation of endogeneous connexin genes in tumours grown in nude mice enforces further experimental strategies to investigate the importance of the different channels to fake the cell biological program of endothelial cells.

Phage display: a molecular tool for the generation of antibodies--a review

Phage display comprises an array of methods, which can be used to display proteins on bacteriophages. We present in this article a summary of techniques, which can be used to express antibody libraries on bacteriophages. Since many researchers are more familiar with the conventional hybridoma technique for production of monoclonal antibodies we describe analogies and differences between these two techniques, both of which are used to reach comparable scientific objectives. We focus on the features which are specific to phage display techniques rather than for hybridoma techniques. These comprise the freedom to choose other animals than the mouse for immunization, the enormously large sample (up to 10(9) clones) which can be drawn and immortalized from a single immunized animal and the opportunity to enhance affinity of isolated antibodies by in vitro affinity maturation. The panning techniques, which are used to enrich specifically binding phage antibodies from the huge libraries are briefly summarized.

Oxygen and placental vascular development

Human embryogenesis takes place in a hypoxic environment because the trophoblast shell excludes entry of maternal blood. The first fetal-placental villi develop as trophoblast sprouts. These are invaded by allantoic mesoderm to form secondary villi and are transformed, by vasculogenesis, into tertiary villi. The placental barrier to maternal blood is gradually breached between 8-12 weeks of gestation, due to invasion of placental-bed uteroplacental spiral arteries by the extravillous trophoblast (EVT). Placental oxygen tension thus rises and a phase of branching angiogenesis continues until 24 weeks. Thereafter a gradual shift takes place favoring non-branching angiogenesis. Gas-exchanging terminal villi thus form which are essential for rapid fetal growth and development of a high-flow, low-resistance fetal-placental circulation. Inadequate invasion of the uteroplacental spiral arteries by EVT results in placental ischemia and the development of obstetrical complications--preeclampsia and/or intrauterine growth restriction (IUGR). Placental villi often show evidence of continued branching angiogenesis, as is the case with anemic pregnancy, and pregnancy at high altitude. These structural alterations may reflect continued hypoxia-driven activity of vascular endothelial growth factor (VEGF). By contrast, a minority of severe early-onset IUGR pregnancies exhibit reduced fetal-placental blood flow with elongated maldeveloped villous capillaries. Placenta-like growth factor (PIGF) expression is increased while trophoblast proliferation is reduced, suggesting "hyperoxia" in the placental villous tree. IUGR may thus have two phenotypes--a more common hypoxic and a rarer hyperoxic type. While this concept is gaining acceptance, we have no insight as to the initiating mechanism(s).

Cytogenetic and DNA-fingerprint characterization of choriocarcinoma cell lines and a trophoblast/choriocarcinoma cell hybrid

We report the successful fusion of human choriocarcinoma cells with normal human trophoblast cells to a choriocarcinoma/trophoblast hybrid. The hybrid cells ACH1P were derived from fusion of primary male trophoblast cells with the HGPRT-defective choriocarcinoma cell line AC1-1. The karyotypes of the parental choriocarcinoma cell line JEG-3, its HGPRT-defective mutant clones AC1-1, AC1-5, and AC1-9, and the choriocarcinoma/trophoblast hybrid ACH1P are presented, together with a detailed characterization of the AC1-specific chromosomal marker add(X)(q26) using conventional cytogenetic banding techniques and multiplex-fluorescence in situ hybridization (M-FISH). To our knowledge, this is the first report of a stably proliferating human cell hybrid of trophoblastic origin, providing a unique cell culture model to study trophoblast-related invasion and its underlying genetic mechanisms.

The human placenta is encircled by a ring of smooth muscle cells

The marginal zone of the human term placenta was studied by transmission electron microscopy and immunohistochemistry using antibodies against cytoskeletal filaments, extracellular matrix molecules and endothelial markers. The marginal sinus of the intervillous space is separated from the chorionic and basal plates by a layer of cells expressing vimentin, desmin, alpha- and gamma-smooth muscle actins, and smooth muscle myosin. Also ultrastructurally, these cells share all features with smooth muscle cells. This muscular ring is continuous with the media of uteroplacental veins entering the marginal sinus. In the basal plate the muscle cells may extend far into the central parts of the placenta. The muscular ring is separated from the intervillous space by a layer of endothelial cells. They are continuous with the maternal endothelium of the marginal uteroplacental veins. Moreover this endothelium covers neighbouring parts of the chorionic and basal plates, locally extending to the surfaces of large stem villi. The data suggest (1) that the marginal zone of the intervillous space ('marginal sinus') represents the dilated and merged parts of uteroplacental veins and (2) that lateral growth of the human placenta partly takes place by expansion into the uteroplacental veins. The functional importance of this muscular ring remains unknown.

Expression of the imprinted genes MEST/Mest in human and murine placenta suggests a role in angiogenesis

In the mouse fetus, Mest is widely expressed in mesoderm derived tissues. In separate studies in mice and in humans, it has been shown to be maternally imprinted, that is, only the paternally inherited allele is active. Here, we show that starting with implantation, Mest is also expressed in maternal decidua of the mouse and in placenta of both humans and mice. Expression in murine decidua was restricted to endothelial cells. After Day 7, expression in the decidua gradually decreased. Mest-specific RT-PCR and restriction fragment length variant (RFLV) analysis of decidualized endometrium isolated from (M. musculus x M. spretus)F1 females showed that only the paternally derived Mest allele was activated in the decidual endothelium. In the mouse extraembryonic tissues, Mest transcripts were detected in derivatives of extraembryonic mesoderm only. Here, hemangioblast precursor cells and endothelial cells were positive. At all developmental stages of the mouse, trophoblast-derived cells were clearly devoid of Mest transcripts. In the human placenta MEST transcripts were also detected in hemangioblast precursor cells, however, MEST was also expressed in villous and invasive cytotrophoblast. In a human choriocarcinoma/trophoblastic tumour grown in a nude mouse, human MEST was expressed in the tumour cells, whereas murine Mest was expressed in endothelia of the murine capillaries. The expression pattern exhibited by both Mest and MEST in extraembryonic tissues during development and during formation of choriocarcinoma/trophoblast tumour suggests a functional role of the MEST proteins related to oncofetal angiogenesis. Dev Dyn 2000;217:1-10.