Isolation of Unusually Composed Sialyl-Compounds from Hemofiltrate

Sialyl compounds are essential components of various biological fluids but relatively little is known about their occurrence in the extracellular fluid of patients with end-stage renal disease. As we have developed a macropreparative method for concentrating and desalting a wide range of fractions from diluted biological fluids we have been able to isolate and identify 5 sialooligosaccharides, 3 sialosugarphosphates, 2 monosialoglycopeptides and 1 disialoglycopeptide. The structures have been elucidated predominantly by one and two-dimensional NMR spectroscopy, enzymatic degradation and FAB mass spectrometry.

The accumulation of these compounds in uremic sera may be of particular interest as they may interact in the molecular biology of diseases typically associated with the uremic state, e.g., immune deficiency, neurological disorders, receptor binding abnormalities, complement system disturbances and cell membrane alterations.

Abstract P4-08-03: Mathematical modeling of the unfolded protein response pathway in breast cancer cells

Over 70% of all breast cancers are estrogen receptor positive (ER+) and are treated with endocrine therapies such as aromatase inhibitors or ER-disruptors as part of the standard of care. However, endocrine resistance remains a major clinical challenge for the successful treatment of this disease. ER+ breast cancer cells can escape endocrine therapy-mediated cell death through adaptations in the unfolded protein response (UPR), an evolutionarily conserved cellular stress response pathway that is linked to many other pathways (autophagy, metabolism, anti-oxidant response). To better understand how the UPR pathway promotes endocrine resistance, we built a mathematical model from quantitative measurements of key UPR signaling molecules following treatment of ER+ MCF7 cells (endocrine sensitive, estrogen dependent) with dithiothreitol (DTT). DTT disrupts or prevents protein disulfide bonding and is a potent inducer of the UPR. The same measurements were also made in two MCF7-derived resistant cell lines: LCC1 (sensitive to ER-disruptors, estrogen independent) and LCC9 (resistant to ER-disruptors, estrogen independent). Determining the (minimal) changes to the MCF7 mathematical model needed to adequately capture the data from the resistant cell lines allows us to create specific hypotheses for how the UPR adapts to help produce resistance to endocrine therapies. These hypotheses, in turn, can lead to drug targets for reversing resistance.

Citation Format: Shajahan-Haq AN, Demas DM, Clarke R, Baumann WT. Mathematical modeling of the unfolded protein response pathway in breast cancer cells [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P4-08-03.

[Memorandum IV: Theoretical and Normative Grounding of Health Services Research]

With Memoranda and other initiatives, the German Network for Health Service Research [Deutsches Netzwerk Versorgungsforschung e.V. (DNVF)] is fostering the methodological quality of care research studies for years. Compared to the standards of empirical research, questions concerning the role and function of theories, theoretical approaches and scientific principles have not been taken up on its own. Therefore, the DNVF e.V. has set up a working group in 2013, which was commissioned to prepare a memorandum on "theories in health care research". This now presented memorandum will primarily challenge scholars in health care services research to pay more attention to questions concerning the theoretical arsenal and the background assumptions in the research process. The foundation in the philosophy of science, the reference to normative principles and the theory-bases of the research process are addressed. Moreover, the memorandum will call on to advance the theorizing in health services research and to strengthen not empirical approaches, research on basic principles or studies with regard to normative sciences and to incorporate these relevant disciplines in health services research. Research structures and funding of health services research needs more open space for theoretical reflection and for self-observation of their own, multidisciplinary research processes.

Iridium(iii) hydrido complexes for the catalytic dehydrogenation of hydrazine borane

A series of POCOP iridium hydride complexes with differently substituted aryl backbones catalyse the selective release of one equivalent of hydrogen from hydrazine borane.

Dynamic Modeling of the Interaction Between Autophagy and Apoptosis in Mammalian Cells

Autophagy is a conserved biological stress response in mammalian cells that is responsible for clearing damaged proteins and organelles from the cytoplasm and recycling their contents via the lysosomal pathway. In cases of mild stress, autophagy acts as a survival mechanism, while in cases of severe stress cells may switch to programmed cell death. Understanding the decision process that moves a cell from autophagy to apoptosis is important since abnormal regulation of autophagy occurs in many diseases, including cancer. To integrate existing knowledge about this decision process into a rigorous, analytical framework, we built a mathematical model of cell fate decisions mediated by autophagy. Our dynamical model is consistent with existing quantitative measurements of autophagy and apoptosis in rat kidney proximal tubular cells responding to cisplatin-induced stress.

[Turnover of Non-medical Staff in Outpatient Oncology Practices: Is Building Social Capital a Solution?]

STUDY AIM

While a lot is known about potential and actual turnover of non-medical hospital staff, only few data exist for the outpatient setting. In addition, little is known about actual instruments which leaders can use to influence staff turnover in physician practices. In the literature, the social capital of an organisation, which means the amount of trust, common values and reciprocal behaviour in the organisation, has been discussed as a possible field of action. In the present study, staff turnover as perceived by outpatient haematologists and oncologists is presented and analysed as to whether social capital is associated with that staff turnover. In conclusion, measures to increase the social capital of a practice are presented.

METHODS

The present study is based on data gathered in a questionnaire-based survey with members of the Professional Organisation of -Office-Based Haematologists and Oncologists (N=551). The social capital of the practice was captured from the haematologists and oncologists using an existing and validated scale. To analyse the impact of the practice's social capital on staff turnover, as perceived by the physicians, bivariate correlations and linear regression analyses were calculated.

RESULTS

In total, 152 haematologists and oncologists participated in the study which represents a response rate of 28%. In the regression analyses, social capital appears as a significant and strong predictor of staff turnover (beta=-0.34; p<0.001).

CONCLUSIONS

Building social capital within the practice may be an important contribution to reducing staff turnover although the underlying study design does not allow for drawing causal conclusions regarding this relationship. To create social capital in their practice, outpatient physicians may apply measures that facilitate social interaction among staff, foster trust and facilitate cooperation. Such measures may already be applied when hiring and training new staff, but also continuously when leading employees and when organising work tasks, e.g., by establishing regular team meetings.

Synthesis and Spectroscopic Properties of Some Compounds Related to Benzenamine-4-(9-anthryl)-N,N-dimethyl [ADMA]

The synthesis of several compounds related to ADMA are described in detail. These compounds are characterized by their mass, NMR, and IR-spectra. In addition, the solvent dependent shift of the fluorescence as well as the effect of an electric field on the fluorescence have been measured. The results are in agreement with a two-state model assuming the simultaneous fluorescence from a weakly polar and a highly polar state with dipole moment μ. μ2/a3 (a is Onsager’s radius) has been determined from both effects. The results are in good agreement with an excited state dipole moment of about 60 • 10-30Cm, in the polar state.

Excited States Dipole Moments and Fluorescence Behaviour of Some Derivatives of Dimethylaminobenzonitrile

Two sterically hindered derivatives of dimethylaminobenzonitrile (DMCA) have been synthesized and the dipole moment of their fluorescent excited state has been determined in differently polar solvents. Its value increases with solvent polarity up to a limiting value of (50 + 2.5) • 10-30 Cm. The results are discussed with reference to the twisted intramolecular charge transfer (TICT) state formation in the class of molecules related to DMCA.

[Communication preferences of oncology patients]

PURPOSE

After testing the psychometric properties of a new questionnaire that measures patient preferences for patient-physician communication (KOPRA questionnaire), the communication preferences of cancer patients were described. In order to do this, the preferences were differentiated according to sociodemographic subgroups and a comparison was made to the preferences of patients with chronic back pain and chronic ischaemic heart disease.

METHODS

N=1,635 patients from 31 medical oncology practices were surveyed. For the KOPRA questionnaire, reliability, unidimensionality, and fit to the Rasch model were tested. Hierarchical models were used to conduct subgroup analyses and comparisons with other diseases.

RESULTS

The psychometric properties of the KOPRA are satisfactory to good. For patients, the 4 communication domains (patient participation and patient orientation, effective and open communication, emotionally supportive communication, communication about personal circumstances) measured by the KOPRA questionnaire are equally important. Women generally have higher expectations of the physician's communicative behaviour. Affective communication is considerably more important for cancer patients than for back pain or cardiac patients.

CONCLUSION

The KOPRA questionnaire is well suited for examining the communication preferences of cancer patients. In general, physician behaviour associated with high scores in all 4 KOPRA dimensions is optimal. Especially in cases where the 4 communication aspects conflict with each other, the physician's communication style should be individualised.

FIB preparation and SEM investigations for three-dimensional analysis of cell cultures on microneedle arrays

We report the investigation of the interfaces between microneedle arrays and cell cultures in patch-on-chip systems by using Focused Ion Beam (FIB) preparation and Scanning Electron Microscopy (SEM). First, FIB preparations of micro chips are made to determine the size and shape of the designed microneedles. In this essay, we investigate the cell-substrate interaction, especially the cell adhesion, and the microneedle's potential cell penetration. For this purpose, cross-sectional preparation of these hard/soft hybrid structures is performed by the FIB technology. By applying the FIB technology followed by high-resolution imaging with SEM, new insights into the cell-substrate interface can be received. One can clearly distinguish between cells that are only in contact with microneedles and cells that are penetrated by microneedles. A stack of slice images is collected by the application of the slice-and-view setup during FIB preparation and is used for three-dimensional reconstruction of cells and micro-needles.

Screening of different metal oxide nanoparticles reveals selective toxicity and inflammatory potential of silica nanoparticles in lung epithelial cells and macrophages

In cell culture studies, foetal calf serum (FCS) comprising numerous different proteins is added, which might coat the surface of engineered nanomaterials (ENMs) and thus could profoundly alter their biological activities. In this study, a panel of industrially most relevant metal oxide nanoparticles (NPs) was screened for toxic effects in A549 lung epithelial cells and RAW264.7 macrophages in the presence and absence of FCS. In medium without FCS amorphous SiO2-NPs were the most cytotoxic NPs and induced a significant pro-inflammatory response in both cell types. An increased anti-oxidative response after exposure to SiO2-NPs was, however, only observed in RAW264.7 macrophages. Furthermore, pre-coating of SiO2-NPs with FCS proteins or simply bovine serum albumin abrogated responses in A549 lung epithelial cells. Thus, the protein corona bound to the surface of SiO2-NPs suppresses their biological effects, an issue which needs to be more carefully considered for in vitro-in vivo extrapolations.

A decrease of intracellular ATP is compensated by increased respiration and acidification at sub-lethal parathion concentrations in murine embryonic neuronal cells: measurements in metabolic cell-culture chips

We present a label-free in vitro method for testing the toxic potentials of chemical substances using primary neuronal cells. The cells were prepared from 16-day-old NMRI mouse embryos and cultured on silicon chips (www.bionas.de) under the influence of different parathion concentrations with sensors for respiration (Clark-type oxygen electrodes), acidification (pH-ISFETs) and cell adhesion (interdigitated electrode structures, IDES). After 12 days in vitro, the sensor readouts were simultaneously recorded for 350 min in the presence of parathion applying a serial 1:3 dilution. The parathion-dependent data was fitted by logistic functions. IC(50) values of approximately 105 μM, 65 μM, and 54 μM were found for respiration, acidification, and adhesion, respectively. An IC(50) value of approximately 36 μM was determined from the intracellular ATP-levels of cells, which were detected by an ATP-luminescence assay using micro-well plates. While the intracellular ATP level and cell adhesion showed no deviation from a simple logistic decay, increases of approximately 29% in the respiration and 15% in the acidification rates above the control values were found at low parathion concentrations, indicating hormesis. These increases could be fitted by a modified logistic function. We believe that the label-free, continuous, multi-parametric monitoring of cell-metabolic processes may have applications in systems-biology and biomedical research, as well as in environmental monitoring. The parallel characterization of IC(50) values and hormetic effects may provide new insights into the metabolic mechanisms of toxic challenges to the cell.