The hormone-sensitive adenylate cyclase is a multi-component system embedded in the lipid bilayer of the plasma membrane and serves as a signal transduction system for various membrane receptors. The complete system consists of various receptor molecules, which sensitize the external ligands, the effector enzyme adenylate cyclase, which catalyzes the formation of cyclic AMP from ATP, and two guanine nucleotide-binding regulatory proteins (N or G proteins), which transduce the signals from the receptors to the adenylate cyclase. Depending on the receptor type activated by a ligand, stimulatory or inhibitory, either the stimulatory or the inhibitory N protein is activated and induces stimulation or inhibition of adenylate cyclase with subsequent increase or decrease in cellular cyclic AMP levels. In this paper, the mechanisms of this hormonal signal transduction system and its regulation will briefly reviewed, with some emphasis on the cardiac system.

Adenylyl Cyclases↗

PubMedDate not supplied

TNFalpha-mediated induction of PAI-1 restricts invasion of HTR-8/SVneo trophoblast cells.

The pro-inflammatory cytokine TNFalpha has numerous effects on placental trophoblasts. Here, we investigated the effects of the cytokine on gene expression and function of the extravillous trophoblast cell line HTR-8/SVneo. Wound healing and Matrigel invasion assays demonstrate that TNFalpha impairs motility and invasiveness. In contrast, counting of cumulative cell numbers and FACS analyses revealed that the cytokine did neither affect proliferation nor distribution of cell cycle phases. Immunocytochemistry of the cytokeratin 18 neo-epitope suggests that TNFalpha did not induce apoptosis in HTR-8/SVneo cells. Gelatine zymography and enzyme activity assays of supernatants of TNFalpha-treated cells demonstrate elevation of the pro- and active form of MMP-9 suggesting that increased expression of the protease cannot overcome the TNFalpha-inhibitory effect on cell invasion. Semi-quantitative RT-PCR analyses suggest that the cytokine may not alter mRNA levels of uPA and tPA. However, elevated expression of PAI-1 was detected by RT-PCR, as well as by Northern and Western blot analyses. Supplementation of PAI-1-blocking antibodies restored invasion of TNF-alpha-incubated HTR-8/SVneo cells through Matrigel-coated transwells. In addition, immunocytochemistry revealed nuclear accumulation of the p65 subunit of NFkappaB in the presence of the cytokine. EMSA indicated TNFalpha-induced binding of the inflammatory transcription factor to an NFkappaB consensus sequence and to the NFkappaB recognition site located in the PAI-1 promoter. The data suggest that TNFalpha restricts trophoblast invasion mainly by increasing the expression of PAI-1. Induction of the inhibitor may involve TNFalpha-stimulated activation of NFkappaB.

Antibodies, Blocking↗

PubMedDate not supplied

TNF-alpha/TNFRI in primary and immortalized first trimester cytotrophoblasts.

During the first trimester of pregnancy endogenous expression of tumour necrosis factor (TNF)-alpha has been detected in villous, as well as in proliferating and invading extravillous, trophoblasts suggesting that the protein could be involved in trophoblast differentiation. To gain insights into the putative role of the TNF-alpha signalling pathway, we investigated expression of its receptors, TNFR I and II, in first trimester placentae and early trophoblasts, and studied the influence of the cytokine on cell proliferation and apoptosis. ELISA and RT-PCR revealed secretion/expression of TNFRI protein/mRNA in immortalized ED27 cells and purified first trimester cytotrophoblasts, while soluble TNFRII was undetectable in cell culture supernatants. In agreement, immunohistochemical analyses of first trimester placentae showed that TNFRI is localized to the villous cyto- and syncytiotrophoblast, to the proliferating cytotrophoblasts of the cell islands and cell columns, as well as to extravillous cells invading decidual tissue. TNFRII, however, was absent in early trophoblast populations. Interleukin (IL)-1 and phorbol 12-myristate 13-acetate (PMA) induced shedding of TNFRI from ED27 and primary cells suggesting that under inflammatory conditions the soluble receptor protein may protect from cytotoxic effects of TNF-alpha. Upon incubation with increasing amounts of TNF-alpha no significant changes in DNA-content or cell numbers were found, suggesting that the cytokine does not augment proliferation of primary cytotrophoblasts. High doses of TNF-alpha, however, provoked growth arrest in ED27 cells as evaluated by cell counting, but did not induce necrosis/apoptosis as was assessed by TUNEL assay. In first trimester cells addition of elevated amounts of TNF-alpha resulted in the appearance of TUNEL-positive cells and an increase in caspase-3 enzyme activity suggesting that the TNF-alpha-dependent apoptotic cascade is executed in a portion of the early cytotrophoblasts.

Adult↗

PubMedDate not supplied

[Registries as a method to promote quality improvement--an investigation based on the example of assisted reproduction].

AIMS: Intracytoplasmic sperm injection is a method of assisted reproduction (AR) covered by Statutory Health Care in Germany, since the guidelines of the concerned health authority (Bundesausschuss der Arzte und Krankenkassen--national board of medical doctors and health care insurance) have been changed in 2002, although open questions concerning its risk profile still exist. It is desirable to consider how collection and handling of data about these treatments can be utilised, so that the risks associated with assisted reproduction can be minimised and procedures be regulated in an adequate manner. Therefore this paper investigates the requirements of a national register in order to achieve a fact-based comparison of results. METHOD: Factors influencing the problems around malformation rate and multiple pregnancy in assisted reproduction were searched for in international literature and traced in documentation already available in the German context. Pathways for collection and handling of the problem-associated data are suggested. RESULTS: Up to now relevant data are kept separately. Data links are a precondition, if the existing documentation collected for different purposes should be used to evaluate and survey AR activities. This applies to the following long-standing German data collections: perinatologic and neonatologic survey, obstetric and paediatric patient documentation and the IVF registry. Further more data links to death cause registry and public health data (e. g. health check for school entering children) have to be considered. Comparing different types of international registration best surveys were found by compulsory registries under official control. CONCLUSIONS: Results are suitable for comparison if treatment is carried out under equivalent circumstances and complete standardized data are collected. Foreign examples show that appropriately designed registries contribute to effective assessment in reproductive health technology. Institution-based data aggregation enables benchmarking as means of quality improvement.

Adult↗

PubMedDate not supplied

Effect of surgical repair on the neurologic function in infants with lipomeningocele.

Eighteen children under the age of 1 year underwent surgery for lipomeningocele at our institution between 1983 and 1991. All the patients had neurologic exams and urodynamic studies (UDS) including a cystometrogram and electromyography of the external urethral sphincter pre- and postoperatively. The surgical procedure performed included an untethering of the spinal cord, laser debulking of the lipoma and placement of a dural graft. All the infants presented with a lesion on their back. Two of 10 infants with a normal neurological exam had abnormal UDS preoperatively. Early surgery normalized abnormal preoperative UDS in 5 of 6 (83%) infants with abnormal UDS. Moreover, 3 of 8 (38%) infants with an abnormal neurological exam preoperatively improved after surgery and none worsened. These observations suggest that abnormal urinary tract function in infants with lipomeningocele may be reversible with early prophylactic surgery.

Female↗