Expression of superoxide dismutase and xanthine oxidase in myometrium, fetal membranes and placenta during normal human pregnancy and parturition

Superoxide, an agent which attenuates the half-life of nitric oxide, is metabolized and synthesized by superoxide dismutase (SOD) and xanthine oxidase, respectively. Over the last few years much work has focused on the role of nitric oxide in human parturition. The aim of this study was to determine whether the onset of human parturition is associated with a change in the expression of copper/zinc superoxide dismutase (Cu/Zn SOD), manganese superoxide dismutase (Mn SOD) or xanthine oxidase within the uterus. Samples of myometrium, placenta, decidua and fetal membranes were obtained from women before and after the onset of labour at term. Immunocytochemistry was used to localize Cu/Zn SOD, Mn SOD and xanthine oxidase and measure SOD enzyme activity. Cu/Zn and Mn SOD-like immunoreactivity was detected in syncytiotrophoblast cells, villous stromal cells and endothelial cells of blood vessels in the placenta. In the myometrium Cu/Zn and Mn SOD were localized to myocytes and endothelial cells and to some vascular smooth muscle cells. In the fetal membranes we observed staining for Cu/Zn SOD and Mn SOD in the amnion, chorion, extravillous trophoblast and decidua. There was no difference in SOD enzyme activity or staining intensity for SOD between different cell types before and during labour. Xanthine oxidase immunoreactivity was identified in each of the tissues examined and again there was no difference in immunostaining in tissues obtained from women delivered before or after the onset of labour. These results show that the pregnant uterus is capable of both synthesizing and degrading superoxide and suggest that superoxide dismutase and xanthine oxidase may play a role in the maintenance of uterine quiescence during pregnancy, but not in the initiation of parturition.      

Endothelin receptor expression in human decidua

The endothelins are signalling peptides that act via two receptors, ET(A) and ET(B). In the human endometrium, endothelin receptors have been demonstrated in glands and stroma and have been shown to vary during the course of the menstrual cycle. The present study was undertaken to determine whether or not expression of endothelin receptors changes during pregnancy or after administration of exogenous progestagens. The expression of the receptors was correlated with the appearance of basement membrane components during decidualization of the endometrial stroma. Decidual specimens (n = 15) were obtained during the first trimester of pregnancy and 10 at term. Sixteen pairs of endometrial biopsies were obtained from women with menorrhagia before and after exposure to exogenous progestagens. A total of 15 hysterectomy specimens were used as controls for the expression of stromal basement membrane proteins in the absence of decidualization. Autoradiography was carried out with selective ligands for ET(A) ([125I]-PD 151242) and ET(B) ([125I]-BQ3020). The distribution of ligand binding was then compared with the distribution of laminin alpha2 light chain and collagen IV. ET(A), ET(B), laminin alpha2 light chain, and collagen IV were expressed in stromal decidual cells in the first trimester of pregnancy. ET(B) was also found on endometrial glandular epithelium. Quantitative macro-autoradiography and multiple regression analysis demonstrated a highly significant positive correlation (P < 0.001) between expression of ET(B) and laminin alpha2 light chain. In the third trimester qualitative examination suggested a reduction of ET(A) in the stroma. Progestagen-induced decidua exhibited a similar pattern to that found in first trimester decidua. This study has demonstrated up-regulation of ET(B) during the progesterone- dependent process of decidualization and suggests a paracrine or autocrine role for endothelins in the decidua.      

Afferent high strength tetanizations favour potentiation of the NMDA vs. AMPA receptor-mediated component of field EPSP in CA1 hippocampal slices of rats

Long-term potentiation (LTP) of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and N-methyl-D-aspartate (NMDA) receptor-mediated components of 'dual-component' field excitatory postsynaptic potentials (fEPSP-A and fEPSP-N) was studied in the CA1 stratum radiatum in hippocampal slices of rats. Relative degrees of LTP of these fEPSP components were compared for tetanizations with low and high strengths. Magnitudes of fEPSP-A and fEPSP-N were estimated in parallel with a least-square fitting of a short-latent (0.1-8.8 ms) fragment of evoked responses by a weighted sum of 'basic' fEPSP-A and fEPSP-N, obtained during a short preliminary application of d-2-amino-5-phosphonovalerate (APV). We found that low-strength tetanizations selectively potentiated fEPSP-A, while high strength tetanizations potentiated both fEPSP components. These results demonstrate in the experiments with parallel measurements of fEPSP-A and fEPSP-N that LTP of these components differ depending on the strength of afferent tetanization. Unequal potentiation of the commissural-collateral and excitatory local-circuit synapses, which presumably contain different amounts of the AMPA and NMDA receptors, is discussed as the most probable explanation for these results.     

Cytogenetic studies in non-African Burkitt lymphoma

A particular translocation between chromosomes 8 and 14 has been found repeatedly in cytogenetic studies of Burkitt lymphoma, both of African and non-African origin. We report here our findings in cytogenetic studies of direct tumor preparations from 18 non-African Burkitt lymphoma patients, 9 of whom also had cell lines available for study. A t(8;14) was found in direct tumor material in 10 of the 18 patients. Seven of the 9 cell lines had a t(8;14). A total of 15 patients had either a t(8;14) or a 14q+ present in tumor material and/or cell lines. In addition, 8 patients had a peculiar marker chromosome 1. The t(8;14) was not found in every malignant cell and, where present, it was rarely the sole karyotypic abnormality. The relationship of the t(8;14) to the evolution of the tumor is discussed.     

Paraganglioma of the nasal cavity: a case report

We describe the case of a 72-year-old woman presenting with a 1-year history of recurrent epistaxis and unilateral progressive nasal obstruction with associated rhinolalia resulting from the presence of a tumor mass occupying two-thirds of the right nasal cavity. Histopathologically, neoplastic cells or "chief cells" were arranged in well-defined nests, which had the classic alveolar or so-called "zellballen" pattern. Immunohistochemical studies highlighted the presence of S-100 protein-positive sustentacular cells located at the periphery of the clusters of chief cells. The chief cells showed a diffuse and intense positivity for neuron-specific enolase and synaptophysin. A diagnosis of paraganglioma was made. The lesion was excised completely and the patient did not develop recurrences or distant metastases after 8 months of follow-up. Paragangliomas arising in the nasal cavity and paranasal sinuses are extremely rare tumors. We report on the clinical, histopathological and immunohistochemical findings of our case and review the cases previously described in the literature.     

Improving evidence based cardiac care and policy implementation over the patient journey: the potential of coronary heart disease registers

Coronary heart disease registers offer considerable potential for providing increased support for practitioners, facilitating improvements in patient care, and allowing efficient monitoring of care provision and outcomes.     

Regression of experimental Burkitt's lymphoma induced by Epstein-Barr virus-immortalized human B cells

Epstein-Barr virus (EBV)-immortalized human B cells survive only transiently when injected subcutaneously into athymic mice, whereas Burkitt's lymphoma cells give rise to progressively growing subcutaneous tumors. In this study, we tested whether these Burkitt's tumors could be induced to regress via a bystander effect induced by EBV-immortalized B cells. Simultaneous inoculation of EBV-immortalized B cells and Burkitt's lymphoma cells in the same subcutaneous site resulted in tumors that regressed with necrosis and scarring. Similarly, simultaneous inoculation of EBV-immortalized B cells and Burkitt's lymphoma cells in separate subcutaneous sites resulted in regression of a proportion of the Burkitt's tumors. Furthermore, most of the established human Burkitt's tumors regressed with necrosis and scarring after intratumor inoculations with EBV-immortalized B cells. The EBV-immortalized B cells continued to exert this antitumor effect even when killed with irradiation. The experimental approach to Burkitt's lymphoma treatment described here exploits the ability of athymic mice to reject EBV-immortalized B cells to target an effective antitumor response to malignant cells normally incapable of eliciting it.