Gonadotropin releasing hormone in first trimester human placenta: isolation, partial characterisation and in vitro biosynthesis

Using a specific radioimmunoassay for gonadotropin releasing hormone, the presence of gonadotropin releasing hormone like material in the first trimester human placenta has been demonstrated. The material has been partially characterized using carboxy methyl cellulose chromatography, high pressure gel permeation chromatography and reverse phase C18 high pressure liquid chromatographic analysis. Analysis for bioactivity revealed that placental gonadotropin releasing hormone is much more active than synthetic gonadotropin releasing hormone in in vitro rat pituitary lutinising hormone release assay. In vitro biosynthetic studies using labelled precursors and immunoaffinity chromatography indicated that first trimester human placenta synthesizes gonadotropin releasing hormone like material

Regulation of DNA synthesis and the cell cycle in human prostate cancer cells and lymphocytes by ovine uterine serpin

<p>Abstract</p> <p>Background</p> <p>Uterine serpins are members of the serine proteinase inhibitor superfamily. Like some other serpins, these proteins do not appear to be functional proteinase inhibitors. The most studied member of the group, ovine uterine serpin (OvUS), inhibits proliferation of several cell types including activated lymphocytes, bovine preimplantation embryos, and cell lines for lymphoma, canine primary osteosarcoma and human prostate cancer (PC-3) cells. The goal for the present study was to evaluate the mechanism by which OvUS inhibits cell proliferation. In particular, it was tested whether inhibition of DNA synthesis in PC-3 cells involves cytotoxic actions of OvUS or the induction of apoptosis. The effect of OvUS in the production of the autocrine and angiogenic cytokine interleukin (IL)-8 by PC-3 cells was also determined. Finally, it was tested whether OvUS blocks specific steps in the cell cycle using both PC-3 cells and lymphocytes.</p> <p>Results</p> <p>Recombinant OvUS blocked proliferation of PC-3 cells at concentrations as low as 8 μg/ml as determined by measurements of [³H]thymidine incorporation or ATP content per well. Treatment of PC-3 cells with OvUS did not cause cytotoxicity or apoptosis or alter interleukin-8 secretion into medium. Results from flow cytometry experiments showed that OvUS blocked the entry of PC-3 cells into S phase and the exit from G₂/M phase. In addition, OvUS blocked entry of lymphocytes into S phase following activation of proliferation with phytohemagglutinin.</p> <p>Conclusion</p> <p>Results indicate that OvUS acts to block cell proliferation through disruption of the cell cycle dynamics rather than induction of cytotoxicity or apoptosis. The finding that OvUS can regulate cell proliferation makes this one of only a few serpins that function to inhibit cell growth.</p

Återvinning av motorvärme i lastbilsmotorergenom att kombinera ett evaporativt motorkylningssystemmed en Rankine-cykel.

Engine Cooling losses constitutes about 20% of the injected fuel energy in a modern heavy duty truck diesel engine. The objective of this Master Thesis Project is to investigate flow boiling cooling as a thermally efficient method for waste heat recovery as well as a good solution for precision cooling. First, an engine heat transfer model was implemented on GT-suite software in order to estimate heat fluxes within the engine cylinder. Liners being less thermally constrained than the cylinder head, flow boiling cooling was then investigated in the liner’s water jackets. A more adapted heat transfer model taking into account both gas side and cooling side of the liner was thus implemented on Simulink. Unlike commercials software, this simple model allowed to implement the relevant two-phase heat transfer correlations and to study in details the boiling flow behaviors. The hydraulic diameter of the water jackets, the fluid saturated pressure and the surface area of heat transfer are the major parameters and they were studied for various mass flow rate in order to analyze how they influence wall temperature and heat transfer. This study showed good operating conditions for very low mass flow rate (about 1% of the typical mass flow rate for liquid convective cooling). Due to flow control issues, it implied the consideration of other fluids such as refrigerants but showed good prospect for cooling system simplification. This flow boiling model was finally inserted in a complete Rankine loop model using water as a working fluid to study potential efficiency improvements. A Rankine loop using water as a working fluid would thus improve the heat recovery of the considered engine of about 4.8% of the net engine brake power, recovering heat from the liners and the exhaust gases at 1800RPM, full load. Further simulations have also been led with R245fa, which shows a WHR of about 5.5% of the net engine brake power at 1800RPM, full load.Motorns kylförluster utgör ca 20 % av energin som injiceras i dieselmotorn på en modern lastbil. Målet med detta examensarbete är att undersöka om flödes kokande kylning är en termiskt effektiv metod för att återvinna spillvärmes och en effektiv lösning för precisionskyla. Först genomfördes en motorvärmeöverföringsmodell på GT-suite för att beräkna värmeflöden i motorcylindern. Eftersom cylinderfoder är mindre termiskt begränsade än topplockundersöktes flödes kokande kylning i cylinderfoder. En mer anpassad värmeöverföringsmodell med hänsyn till både avgas- och kylmedelsidan på cylinderfoder genomfördes således med Simulink. Till skillnad från kommersiella programvaror, gör denna enkla modell det möjligt att utföra 2-fas värmeöverföringskorrelationer och studera flödes kokande beteendet i detalj. De viktigaste parametrarna (vattenmantelns hydrauliska diameter, vätsketrycket och ytan av värmeöverföringarna) studerades för olika massflöden för att analysera hur de påverkar väggtemperatur och värmeöverföring. Undersökningen visade goda arbetsförhållanden för mycket låga massflöden (ca 1 % av det typiska massflödet för konvektiv vätskekylning). På grund av problem med flödesregleringen, behövde andra vätskor beaktas som köldmedier men hade god potential för att kyla systemet effektivt. För att studera potentiella förbättringar av energieffektiviteten infördes den flödes kokande modellen slutligen i en komplett modell av en Rankine-krets där vatten användes som kylmedel. En Rankine-krets med vatten skulle förbättra värmeåtervinningen på den avsedda motorn med 4,8 % motorns bromskraft, genom att återvinna värme från cylinderfoder och avgaserna vid 1800 RPM, full belastning. Ytterligare simulationer har också hållits med R245fa, som visar en återvinning av spillvärmen med 5,5 % av motorns bromskraft vid 1800 RPM, full belastning

Gonadotropin-releasing hormone in first trimester human placenta: isolation, partial characterization and in vitro biosynthesis

Using a specific RIA for gonadotropin-releasing hormone (I), the presence of I-like material in the 1st trimester human placenta was demonstrated. The material has been partially characterized using CMC chromatog., high pressure gel permeation chromatog., and reverse-phase C18 HPLC anal. Anal. for bioactivity revealed that placental I is much more active than synthetic I in in vitro rat pituitary LH release assay. In vitro biosynthetic studies using labeled precursors and immunoaffinity chromatog. indicated that 1st trimester human placenta synthesizes I-like material

Gonadotropin-releasing hormone (GnRH) stimulates both secretion and synthesis of human chorionic gonadotropin (hCG) by first trimester human placental minces in vitro

An in vitro system using the minces of placental villi from first trimester human pregnancy (6-10 weeks) has been validated to examine the effect of addition of GnRH and its analogues on hCG secreted into the medium. Addition of low concentration of GnRH or its analogues (1 × 10(-8) M to 1 × 10(-6) M) resulted in an increase in the quantity of hCG in the medium, while addition of high concentrations of GnRH resulted in an inhibitory effect. Of the analogues tested, Buserelin was highly effective in exerting an inhibitory effect. A significant increase in 35S-methionine incorporation into immunoprecipitable hCG was noticed in the presence of GnRH. These results suggests that GnRH stimulates both synthesis and secretion of hCG by first trimester human placenta