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Biomedical subjects

L Rieger

Publications and source records attributed to L Rieger.

At least 19 recordsLinked to original sources
PubMed2006

Increased tartrate-resistant acid phosphatase (TRAP) expression in malignant breast, ovarian and melanoma tissue: an investigational study.

BACKGROUND: Tartrate-resistant acid phosphatase (TRAP) is a metalloprotein enzyme that belongs to the acid phosphatases and is known to be expressed by osteoclasts. It has already been investigated as a marker of bone metastases in cancer patients. In this study, which examined the value of serum TRAP concentrations as a marker of bone disease in breast cancer patients, we observed high concentrations of TRAP even in patients without bone metastases. To elucidate this phenomenon, we examined the expression of TRAP in breast cancer cells and the cells of several other malignancies. METHODS: TRAP concentrations in the serum of tumor patients were determined by ELISA. The expression of TRAP in breast, ovarian, and cervical cancer and malignant melanoma was analyzed by immunohistochemistry. RT-PCR and immunocytology were used to evaluate TRAP expression in cultured tumor cells. RESULTS: A marked increase in serum TRAP concentrations was observed in patients with breast and ovarian cancer, regardless of the presence or absence of bone disease. TRAP expression was found in breast and ovarian cancers and malignant melanoma, while cervical cancer showed only minimal expression of TRAP. Expression of TRAP was absent in benign tissue or was much less marked than in the corresponding malignant tissue. TRAP expression was also demonstrated in cultured primary cancer cells and in commercially available cell lines. CONCLUSION: Overexpression of TRAP was detected in the cells of various different tumors. TRAP might be useful as a marker of progression of malignant disease. It could also be a potential target for future cancer therapies.

Acid Phosphatase↗
PubMed2006

Modelling of aeration systems at wastewater treatment plants.

A model for the response time of aeration systems at WWTPs is proposed. It includes the delays caused by the air supply system (consisting of blowers, throttles and pipes), the rise time of the air bubbles and all control loops except the master DO controller. Beside a description of the required step-change experiments, different approaches for model calibration are given depending on the available data. Moreover, the parameters for the oxygen transfer and the response time of the aeration system model are not clearly identifiable. The model can be used for simulation studies which compare different types of controllers under changing loading and process conditions. The results from full-scale experiments at three different plants show that the response times of the aeration systems are in the range of 4-5 min. Taking all processes and time constants into account, some 30 min are needed to reach a new steady state after a step change of the airflow rate.

Air Movements↗
PubMed2006

Uncertainties of spectral in situ measurements in wastewater using different calibration approaches.

Three calibration methods were applied to UV/VIS spectra recorded in the influent of six wastewater treatment plants (WWTPs) to measure total COD (CODtot), filtered COD (CODfil), nitrate and nitrite nitrogen (NO(x)-N) and total suspended solids (TSS). It could be shown that a calibration of the sensor using data sets from four Swiss WWTPs leads to an improvement of the precision in comparison to the global calibration provided by the manufacturer. A calibration to the specific wastewater matrix always improves the results and gives the highest accuracy. For CODtot a mean coefficient of variation CVx of 12.5% could be reached, whereas for NOx-N only weak results were achieved (average CVx = 36%).

Calibration↗
PubMed2005

Natural killer cells and dendritic cells at the human feto-maternal interface: an effective cooperation?

Human endometrium and in particular decidua, harbours a considerable population of immunocompetent cells. The most prominent of these are uterine natural killer (uNK) cells, which differ considerably from their peripheral blood counterparts in terms of both gene expression and function. Recently, the existence of DC-SIGN positive immature dendritic cells (DCs) in human decidua has been demonstrated. Evidence exists that immature DCs are required for the initiation and maintenance of peripheral tolerance, whereas mature DCs, which are only found in minimal amounts in human decidua, are associated with a Th1 polarization of T cells. Although the study of uNK-DC cross-talk is only beginning, it may in the future provide important insights into how acceptance of the fetus by the maternal immune system is mediated.

Dendritic Cells↗
PubMed2005

A case of metastasizing invasive hydatidiform mole. Is less--less good? Review of the literature with regard to adequate treatment.

BACKGROUND: Patients with invasive hydatidiform moles (IHM) have a good prognosis. Even if disease has spread, monocytostatic treatment might be sufficient if the diagnosis has been histologically confirmed. Established classifications divide gestational trophoblastic disease (GTD) including choriocarcinoma into cases with "high" and "low" risk. Without respect to histology "high-risk" cases are recommended to obtain polychemotherapy. CASE: A 40-year-old nullipara underwent hysterectomy for persistent vaginal bleeding after she had already been treated with curettage for hydatidiform mole. An IHM was pathohistologically confirmed. There were no signs of pulmonary spread or other metastases at the time of surgery. Postsurgically persistent beta-hCG levels lead to thorough staging, which revealed multiple pulmonary metastases and a vaginal metastasis. Despite metastasizing GTD with poor prognosis criteria she was treated with single agent therapy. Eight cycles of two weekly methotrexate (MTX) were administered. All sites of metastases responded and our patient is still fine after one year of follow-up. CONCLUSION: With respect to this and other reports monochemotherapy can be a reasonable primary treatment for metastatic IHM.

Adult↗
PubMed2004

Antigen-presenting cells in human endometrium during the menstrual cycle compared to early pregnancy.

OBJECTIVE: Human endometrium and early pregnancy decidua harbor a considerable and diverse population of antigen-presenting cells (APC). Changes in the number and distribution of macrophages and dendritic cells (DC) could point to a possible role of these immunocompetent cells in implantation and success of early pregnancy. METHODS: Uterine tissue was obtained from 22 women undergoing hysterectomy for bleeding disorders or dysmenorrhea and from 11 women undergoing legal abortion. Tissue was investigated with antibodies against CD14, CD68, CD83, DC-SIGN, Ki-67, and human leukocyte antigen (HLA)-DR using single and double immunohistochemical staining techniques. RESULTS: The number of CD14(+) cells was stable during all phases of the menstrual cycle and early pregnancy. In comparison to nonpregnant endometrium, DC-SIGN(+) cells showed a higher proliferation rate and were found associated in clusters with CD56(+) natural killer (NK) cells in early pregnancy. In the late secretory phase of the menstrual cycle, numbers of CD83(+) (P <.01) cells were significantly higher than in other endometrial phases and early pregnancy. HLA-DR(+) expression was significantly increased in early pregnancy but remained unchanged throughout the menstrual cycle. CONCLUSION: The presence of DC-SIGN(+) cells during the menstrual cycle and their proliferation in early pregnancy suggests an important role of these cells with regard to the balance between defense against pathogens and tolerance of the fetal allograft. Whether the increase of CD83(+) mature DC and CD68(+) macrophages in the late secretory phase is caused by hormonal stimuli and/or is due to changes of the cytokine/chemokine micromilieu remains to be investigated.

Abortion, Induced↗
PubMed2004

Improvement of nitrogen removal at WWTP Zürich Werdhöelzli after connection of WWTP Zürich-Glatt.

Optimisation of nitrifying activated sludge plants towards nutrient removal (denitrification and enhanced P-removal) leads to a substantial reduction of operating costs and improves effluent and operating conditions. At WWTP Zürich-Werdhöelzli, initially designed for nitrification only, an anoxic zone of 28% of total activated sludge volume was installed and allowed 60% nitrogen elimination besides several other optimisations. In 2001 the operation of WWTP Zürich-Glatt was stopped and the wastewater was connected to WWTP Werdhöelzli. To improve nitrogen removal, WWTP Werdhöelzli co-financed two research projects; one for separate digester supernatant treatment with the anammox process operating two SBRs in series and the other applying NH4 sensors for aeration control in order to decrease energy consumption and raise effluent quality. The results of both projects and the consequences for WWTP Werdhöelzli are discussed in this paper.

Ammonia↗
PubMed2004

A guideline for simulation studies of wastewater treatment plants.

A guideline for simulation studies of wastewater treatment plants is proposed. The aim of the HSG-guideline is to define a reference quality level that helps to make the results of simulation studies comprehensible and comparable and therefore increases the quality and reliability of mathematical modelling in wastewater treatment. The paper gives a summary of the HSG-guideline, written by a group of university members from Germany, Austria and Switzerland.

Bioreactors↗
PubMed2004

Computer-aided monitoring and operation of continuous measuring devices.

Extended studies of measuring and control systems in activated sludge plants at EAWAG revealed that the measuring devices remain the weakest point in control applications. To overcome this problem, a software package was developed which analyses and evaluates the residuals between a reference measurement and the sensor and collects the information in a database. The underlying monitoring concept is based on a two-step evaluation of the residuals by means of statistical evaluations using control charts with two different sets of criteria. The first step is a warning phase in which hints on probable errors trigger an increase in the monitoring frequency. In the second step, the alarm phase, the error hypothesis has to be validated and should allow immediate and targeted reactions from the operator. This procedure enables an optimized and flexible monitoring effort combined with an increased probability of early detection of systematic measuring errors. Beside the monitoring concept, information about the measuring device, the performed servicing actions and the responsibilities is stored. Statistical values for the quantitative characterization of the measuring system during operation will be given. They are needed to parameterise controllers or to guarantee the accuracy of the instrument in order to allow reliable calculations of effluent tax. In contrast to other concepts, not only is the measuring device examined under standard conditions, but so is the entire measuring chain from the liquid to be analysed to the value stored in the database of the supervisory system. The knowledge of the response time of the measuring system is then required in order to allow a comparison of the corresponding values.

Computers↗
PubMed2004

Application of ion-sensitive sensors in water quality monitoring.

Within the last years a trend towards in-situ monitoring can be observed, i.e. most new sensors for water quality monitoring are designed for direct installation in the medium, compact in size and use measurement principles which minimise maintenance demand. Ion-sensitive sensors (Ion-Sensitive-Electrode--ISE) are based on a well known measurement principle and recently some manufacturers have released probe types which are specially adapted for application in water quality monitoring. The function principle of ISE-sensors, their advantages, limitations and the different methods for sensor calibration are described. Experiences with ISE-sensors from applications in sewer networks, at different sampling points within wastewater treatment plants and for surface water monitoring are reported. An estimation of investment and operation costs in comparison to other sensor types is given.

Calibration↗
PubMed2004

Spectral in-situ analysis of NO2, NO3, COD, DOC and TSS in the effluent of a WWTP.

An in-situ UV spectrometer was applied to the effluent of a WWTP in Switzerland and calibrated using a multivariate calibration algorithm based on PLS regression. Except for nitrite, the calibration was based on comparative measurements of the effluent in the plant laboratory. Samples made of stock solution added to three different matrices prepared in the EAWAG laboratory were used for the nitrite calibration because the effluent concentrations were always in the range of 0.06-0.26 mg/l. The results show very good precision for nitrite and nitrate. The measuring range for COD and DOC was not completely covered by the measurements, so the meaningfulness of the results is limited. Nevertheless the precision obtained for soluble COD is high enough for most applications at WWTPs. The accuracy of the TSS measurement is unsatisfactory as regards effluent limits since the spectrometer used does not cover the wavelength region up to 700 nm, which gives better signals for TSS calibration due to its strong correlation with turbidity.

Algorithms↗
PubMed2003

[Placenta praevia percreta--a serious complication after previous cesarean section].

A 36-year-old G4P1 presented at 20 weeks gestation with vaginal bleeding. Her obstetrical history was significant for two first-trimester spontaneous abortions requiring curettage and a cesarean section. On admission placenta praevia was suspected by ultrasound. A placenta percreta was suspected by ultrasound follow-up at 30 weeks. At 33 weeks she underwent cesarean section because of serious vaginal bleeding. The profound blood loss with consecutive coagulopathy required an emergency hysterectomy and multiple blood transfusions. Placenta percreta is a rare but dramatic complication after previous cesarean section. This should be kept in mind as the rate of elective cesarean sections is rising continuously.

Abortion, Spontaneous↗
PubMed2003

Immunocompetent cells in the endometrium of fetuses and children.

BACKGROUND: Although the immunocompetent cells of the adult human endometrium are well characterized, there is little information about these cells in the developing uterus. This study was undertaken to investigate the distribution of leukocyte subpopulations in the endometrium of fetuses and children. METHODS: Uterine tissue obtained at autopsy from fetuses (n = 11) and neonates/children (n = 9) between 17 weeks gestation and 5(1/2) years of age was investigated with antibodies against various leukocyte subsets by immunohistochemical staining techniques. RESULTS: The densities of CD45+ and CD68+ cells were significantly higher in the endometrium of neonates/children than in that of fetuses. CD14+ monocytes represented the largest leukocyte subpopulation in both groups. CD56+ natural killer cells and HLA-DR+ antigen-presenting cells were absent from fetal endometrium. There were no differences in density of CD3+ T cells between the two groups, but CD4+ T helper cells were found only in fetal endometrium. CONCLUSIONS: The endometrial leukocyte population of fetuses and small children is different from that seen in adult women. The appearance of CD56+ and HLA-DR+ cells in endometrium seems to be a post-natal event, which may be induced by the changes in hormone levels and/or the adaptation of the local immune system to the changing microenvironment.

Antigen-Presenting Cells↗
PubMed2003

Progress in sensor technology--progress in process control? Part 1: sensor property investigation and classification.

To ensure correctly operating control systems, the measurement and control equipment in WWTPs must be mutually consistent. The dynamic simulation of activated sludge systems could offer a suitable tool for designing and optimising control strategies. Ideal or simplified sensor models represent a limiting factor for comparability with field applications. More realistic sensor models are therefore required. Two groups of sensor models are proposed on the basis of field and laboratory tests: one for specific sensors and another for a classification of sensor types to be used with the COST simulation benchmark environment. This should lead to a more realistic test environment and allow control engineers to define the requirements of the measuring equipment as a function of the selected strategy.

Environmental Monitoring↗
PubMed2003

Progress in sensor technology--progress in process control? Part II: results from a simulation benchmark study.

To show the impact of sensor behaviour on the control result, four strategies for aeration control are tested using different sensor characteristics. It is demonstrated, on the one hand, how an increasing response time will limit the achievable control quality and, on the other hand, how a given sensor characteristic can be taken into account for the controller design. The presented tests show that an improvement potential by control for WWTPs is available but this potential is limited compared to proper DO control with fixed set-points. To activate this control potential, sufficient control authority must be available and a careful control design is required. It can be shown that using feedback control, sensors with a small response time have significant advantages compared to conventional sensors. Using feed forward control, the improvement potential by control is considerably higher and additionally, the sensor delay can be integrated into the controller design. The presented discussion is based on simulation studies performed on a standardised benchmark case. For these tests it was necessary to include sensor models into the simulation model. It can be stated that the usage of sensor models is necessary for the application of dynamic simulation for the design and evaluation of WWTP control and in general to achieve realistic results.

Automation↗
PubMed2002

[Expression of the molecules HLA-G and HLA-E modulates cytokine production of monocyte generated dendritic cells].

OBJECTIVE: Preferential secretion of Th1-like cytokine is mainly a property of monocyte derived dendritic cells (DC). Since normal early pregnancy is characterized by a shift towards a Th2-like cytokine pattern, it may be assumed that cytokine secretion by DC during early pregnancy could be modulated by the non-classical HLA molecules G and E present on invasive trophoblast. MATERIAL AND METHODS: DC were cultivated from monocytes isolated from peripheral blood mononuclear cells. DC were cocultured with K-562 leukemia cells lacking the class I and II HLA antigens transfected with either HLA-G or HLA-E or ultratransfected cells (controls) and the concentrations of IL-8, IL-10, IL-12p70, IL-18 and TNF-alpha were measured in the supernatants by ELISA. RESULTS: Coculture with ultratransfected cells resulted in a significant increase of the production of IL-8 and TNF-alpha by mature and immature DC and of IL-10 by immature DC (p < 0.01). When cocultured with HLA-G and HLA-E transfected K-562 cells, the secretion of IL-8 by immature and mature DC and that of IL-10 and TNF-alpha by immature DC was significantly (p < 0.01) decreased. The contact with HLA-G and HLA-E transfected cells had no effect on the production of IL-12p70 and IL-18 by DC. CONCLUSIONS: These results show that DC react with an increased cytokine release upon contact with cells lacking HLA class I and II antigens. The suppressive effect of HLA-G and HLA-E on the secretion of TNF-alpha (Th1 cytokine), IL-10 (Th2 cytokine) and IL-8 (chemokine) by immature DC could be interpreted as further evidence for the central immunotolerance role of HLA-G and HLA-E during early pregnancy.

Cells, Cultured↗
PubMed2002

Th1- and Th2-like cytokine production by first trimester decidual large granular lymphocytes is influenced by HLA-G and HLA-E.

During normal early pregnancy, a particular immune environment in the decidua and the expression of non-classical HLA-G and HLA-E molecules on the invading trophoblast are assumed to be essential for the tolerance of the fetus. To assess whether HLA-G and HLA-E influence the cytokine production of their putative target cells [large granular lymphocytes (LGL)], we analysed the concentrations of tumour necrosis factor (TNF-alpha), interferon (IFN)-gamma, interleukin (IL)-10, IL-13 and granulocyte-macrophage colony stimulating factor (GM-CSF) in supernatants of isolated first trimester LGL co-cultured with HLA-G or HLA-E transfected K-562 leukaemia cells lacking the classical HLA class I and II molecules. In comparison with that observed with untransfected K-562 cells, co-culture of LGL with HLA-G-expressing cells significantly reduced the concentration of all cytokines investigated (TNF-alpha, IL-10 and GM-CSF, P < 0.01; IFN-gamma and IL-13, P < 0.05). In contrast, co-culture of LGL with HLA-E-expressing cells significantly (P < 0.01) decreased only IL-10 production, although a strong tendency towards reduced IL-13 levels was also observed. In the co-culture system presented, membrane-bound HLA-G and, to a lesser extent, HLA-E expression affected cytokine release by decidual LGL in a manner not consistent with the Th1/Th2 paradigm. In conclusion, our data are indicative of a general immune-suppressive effect of HLA-G on LGL activity.

Cells, Cultured↗