Nanoanalysis of plasma volatile organic compounds using novel DNA-decorated carbon nanotube vapor sensors to noninvasively distinguish ovarian and pancreatic cancer from benign and control samples

5544

Background: All cells release volatile organic compounds (VOCs) which emanate from body fluids. Our previous preliminary proof of concept study demonstrated that VOCs released from tissue and plasma from ovarian cancer patients are distinct from those released from samples of patients with benign tumors and controls. We seek to create a sensitive and specific, high-throughput screening test for cancer based on analysis of VOCs using novel nanosensors, first targeting cancers with limited clinical screening modalities. In this study we use these sensors to distinguish vapor characteristics in plasma samples from patients with ovarian and pancreatic cancer from benign specimens and controls. Methods: VOCs emanating from.5 mL of thawed, previously banked plasma samples from 93 total individuals were analyzed using a 10-channel nanoelectronic olfaction (“e-nose”) system based on single-stranded DNA-decorated single-walled carbon nanotube (DNA-NT) vapor sensors. Analysis was performed on samples from 20 patients with ovarian cancer, 20 with benign ovarian tumors and 20 age-matched women as well as 13 patients with pancreatic cancer, 10 patients with benign pancreatic disease, and 10 age- and sex-matched controls. All ovarian cancer patients and comparators were non-smokers, while 1 pancreatic patient and 1 corresponding control were current smokers. The sample set included cancer patients with both early- and late-stage disease. All cancer specimens were obtained proximal to initial diagnosis and prior to initiation of therapy. With a test time of approximately 20 minutes per sample, the array output for each individual sample creates a vector in a 10-dimensional sensor space. The ability of the nanosensor array to discriminate between malignant, benign, and healthy groups was investigated using linear discriminant analysis (LDA), support vector machine (SVM), k-nearest neighbors (KNN), and random forest classification algorithms. Each algorithm was trained and tested according to leave-one-out and repeated stratified k-fold cross-validation methods. Results: Compared to their corresponding benign and control specimens, the DNA-NT sensor array was able to discriminate the VOCs from ovarian cancer with 95% accuracy and pancreatic cancer with 90% accuracy. Plasma samples from patients with early-stage ovarian and pancreatic cancers were correctly identified by the algorithms. Conclusions: Nano-enabled DNA coated vapor sensors were able to distinguish the VOC pattern between cancer, benign and control samples in both ovarian and pancreatic cancer. We provide strong evidence that ovarian and pancreatic cancer alters the VOC pattern emanating from plasma. Our results provide optimism that a diagnostic approach based on vapor detection of ovarian and pancreatic cancer is achievable.

Mental health from childhood to adulthood: Results of the 11-year follow-up of the BELLA study

Background

Mental health problems in children, adolescents and young adults are highly prevalent and cause a significant burden for both individuals and society, resulting in a high relevance to public health. Longitudinal studies are needed to provide profound population-based data on mental health and well-being. In the present study, first results of the 11-year follow-up of the German BELLA study are presented. These include age- and gender-specific courses of general health and well-being, long-term health outcomes of mental health problems, and the utilisation of mental health services.

Methods

The longitudinal BELLA study is the module on mental health and well-being within the German Health Interview and Examination Survey for Children and Adolescents (KiGGS). The BELLA study has gathered data since 2003 at five measurement points using standardised measures. In the most recent 11-year follow-up, N = 3,492 young people aged 7 to 31 years participated. Individual growth modeling, linear regression and descriptive analyses were conducted.

Results

Self-reported general health and well-being were both better in younger than older and in male compared to female participants using data from all five measurement points. Mental health problems in childhood and adolescence (measured at baseline) were associated with adverse general, mental and physical health outcomes at 6-year and 11-year follow-ups. About 75 % of children and adolescents with a diagnosed mental disorder were under mental health treatment.

Conclusions

With its 11-year follow-up, the longitudinal BELLA study provides new data on mental health and well-being in German children, adolescents and young adults. Our findings are important for the development of targeted mental health promotion and early prevention strategies. Promising future analyses are planned.

Key messages

The BELLA study provides data on developmental trajectories of mental health from childhood to adulthood, on long-term health outcomes of mental health problems and on mental health care use. The findings of the present study are of great relevance for the development of targeted health promotion and prevention programs.

Risk and resource factors for the development of depression during adolescence and young adulthood

Background

Depression is one of the most common mental disorders in adolescents and young adults worldwide, and causes severe impairments in psychological health, social functioning and employment. The identification of risk and resource factors for depression is an important research aim. The present study aims to investigate which individual, familial and social risk and resource factors in childhood and adolescence are associated with depressive symptoms five years later in a population-based cohort in Germany.

Methods

Analyses were performed using data from the longitudinal BELLA study. Data on risk and resource factors were collected among N = 632 children and adolescents aged 11 to 17 years. Depressive symptoms were measured five years later. The effects of risk and resource factors on depression were investigated using multivariate linear regression analyses. In subsequent models, we explored potential moderator effects of resource factors on the relationship between risk factors and depressive symptoms.

Results

A negative mother-child relationship was associated with stronger depressive symptoms in girls, while school stress was identified as a risk factor in boys. Peer competence was associated with fewer depressive symptoms in girls, and family cohesion served as a resource factor in boys. Moreover, self-efficacy moderated the association between negative mother-child relationship and depressive symptoms. Family cohesion acted as a moderator between peer problems and depressive symptoms.

Conclusions

Our findings provide evidence of gender-specific risk and resource factors for depressive symptoms. Individuals who are exposed to one of the identified risk factors must be monitored during the transition from childhood to adolescence and young adulthood. Gender-sensitive health promotion and early prevention programs are needed.

Key messages

Information concerning risk and resource factors for the development of depressive symptoms during adolescence and emerging adulthood are of high interest for public health, research and practice. The findings of the present study are of great relevance for the development of gender-sensitive health promotion and early prevention programs.

Cancer-ID: Toward Identification of Cancer by Tumor-Derived Extracellular Vesicles in Blood

Extracellular vesicles (EVs) have great potential as biomarkers since their composition and concentration in biofluids are disease state dependent and their cargo can contain disease-related information. Large tumor-derived EVs (tdEVs, >1 μm) in blood from cancer patients are associated with poor outcome, and changes in their number can be used to monitor therapy effectiveness. Whereas, small tumor-derived EVs (<1 μm) are likely to outnumber their larger counterparts, thereby offering better statistical significance, identification and quantification of small tdEVs are more challenging. In the blood of cancer patients, a subpopulation of EVs originate from tumor cells, but these EVs are outnumbered by non-EV particles and EVs from other origin. In the Dutch NWO Perspectief Cancer-ID program, we developed and evaluated detection and characterization techniques to distinguish EVs from non-EV particles and other EVs. Despite low signal amplitudes, we identified characteristics of these small tdEVs that may enable the enumeration of small tdEVs and extract relevant information. The insights obtained from Cancer-ID can help to explore the full potential of tdEVs in the clinic.

Targeting bromodomain-containing protein 4 (BRD4) inhibits MYC expression in colorectal cancer cells

The transcriptional regulator BRD4 has been shown to be important for the expression of several oncogenes including MYC. Inhibiting of BRD4 has broad antiproliferative activity in different cancer cell types. The small molecule JQ1 blocks the interaction of BRD4 with acetylated histones leading to transcriptional modulation. Depleting BRD4 via engineered bifunctional small molecules named PROTACs (proteolysis targeting chimeras) represents the next-generation approach to JQ1-mediated BRD4 inhibition. PROTACs trigger BRD4 for proteasomale degradation by recruiting E3 ligases. The aim of this study was therefore to validate the importance of BRD4 as a relevant target in colorectal cancer (CRC) cells and to compare the efficacy of BRD4 inhibition with BRD4 degradation on downregulating MYC expression. JQ1 induced a downregulation of both MYC mRNA and MYC protein associated with an antiproliferative phenotype in CRC cells. dBET1 and MZ1 induced degradation of BRD4 followed by a reduction in MYC expression and CRC cell proliferation. In SW480 cells, where dBET1 failed, we found significantly lower levels of the E3 ligase cereblon, which is essential for dBET1-induced BRD4 degradation. To gain mechanistic insight into the unresponsiveness to dBET1, we generated dBET1-resistant LS174t cells and found a strong downregulation of cereblon protein. These findings suggest that inhibition of BRD4 by JQ1 and degradation of BRD4 by dBET1 and MZ1 are powerful tools for reducing MYC expression and CRC cell proliferation. In addition, downregulation of cereblon may be an important mechanism for developing dBET1 resistance, which can be evaded by incubating dBET1-resistant cells with JQ1 or MZ1.

87Effects of the chymase inhibitor fulacimstat on adverse cardiac remodelling after acute myocardial infarction - Results of the CHIARA MIA 2 trial

Introduction

Adverse cardiac remodelling represents the most important risk factor for the development of heart failure (HF) after myocardial infarction (MI). Chymase is a protease that generates locally pro-fibrotic factors such as angiotensin II, TGFβ, and matrixmetallproteases that contribute to tissue remodelling.

Purpose

This phase IIa study examined the effects of the chymase inhibitor fulacimstat on functional parameters of adverse cardiac remodelling after acute MI.

Methods

A double-blind, multinational, randomized, placebo-controlled study was performed in patients after first STEMI who were treated with primary percutaneous coronary intervention within 24h of symptom onset. To enrich for patients at risk of adverse remodelling, main inclusion criteria were a left-ventricular ejection fraction (LVEF)≤45% and an infarct size>10% on day 5 to 9 post MI as measured by cardiac MRI. On day 6 to 12 post MI, patients were randomized to treatment with either 25 mg fulacimstat (n=54) or placebo (n=53) twice daily on top of standard of care. The changes in LVEF, LVEDVI, and LVESVI from baseline to 6 months of treatment were analyzed by a central blinded cardiac MRI core laboratory.

Results

Fulacimstat was safe and well tolerated, 64.8% of patients treated with fulacimstat and 75.5% of patients treated with placebo reported treatment emergent adverse events. Fulacimstat achieved exposures that were approximately 10-fold higher than those predicted to be required for minimal therapeutic activity. After six months of treatment, there were no effects of fulacimstat compared to placebo on the changes in LVEF, LVEDVI, and LVESVI (see Table).

Analysis of primary efficacy parameters Parameter Placebo Fulacimstat p-value LVEF (%) baseline 37.2±6.1 39.1±5.5 0.15 6 months 41.2±8.4 42.6±8.4 0.45 delta 4.0±5.0 3.5±5.4 0.69 LVEDVI (mL/m2) baseline 80.0±17.1 77.4±18.2 0.51 6 months 85.1±19.1 84.7±23.4 0.94 delta 5.1±18.9 7.3±13.3 0.54 LVESVI (mL/m2) baseline 50.5±13.0 47.3±12.3 0.26 6 months 51.1±16.9 49.6±18.1 0.71 delta 0.6±14.8 2.3±11.2 0.56 Data are given as mean ± standard deviation.

Conclusion

Fulacimstat was safe and well tolerated in patients with left-ventricular dysfunction (LVD) after first STEMI but had no effect on adverse cardiac remodelling in the experimental setting of this study.

Acknowledgement/Funding

The study was funded by its sponsor BAYER AG

SEM-Raman image cytometry of cells

Correlative and integrated scanning electron microscopy (SEM) and Raman micro-spectroscopy is presented that enables the characterization and identification of different cancer and non-cancer cells through SEM-Raman image cytometry. The hybrid microscopy system enables the acquisition of high resolution SEM images of uncoated cells and the spatial correlation with chemical information as obtained from Raman micro-spectroscopic imaging. A sample preparation protocol and a workflow are presented that are compatible with the demands of hybrid SEM-Raman microscopy. Stainless steel cell substrates were used that are both conductive and give a low optical response in Raman scattering. Correlative and integrated SEM-Raman micro-spectroscopy is illustrated with cells from blood and cells from a SKBR-3 breast cancer cell line.

Modalities for image- and molecular-guided cancer surgery

BACKGROUND

Surgery is the cornerstone of treatment for many solid tumours. A wide variety of imaging modalities are available before surgery for staging, although surgeons still rely primarily on visual and haptic cues in the operating environment. Image and molecular guidance might improve the adequacy of resection through enhanced tumour definition and detection of aberrant deposits. Intraoperative modalities available for image- and molecular-guided cancer surgery are reviewed here.

METHODS

Intraoperative cancer detection techniques were identified through a systematic literature search, with selection of peer-reviewed publications from January 2012 to January 2017. Modalities were reviewed, described and compared according to 25 predefined characteristics. To summarize the data in a comparable way, a three-point rating scale was applied to quantitative characteristics.

RESULTS

The search identified ten image- and molecular-guided surgery techniques, which can be divided into four groups: conventional, optical, nuclear and endogenous reflectance modalities. Conventional techniques are the most well known imaging modalities, but unfortunately have the drawback of a defined resolution and long acquisition time. Optical imaging is a real-time modality; however, the penetration depth is limited. Nuclear modalities have excellent penetration depth, but their intraoperative use is limited by the use of radioactivity. Endogenous reflectance modalities provide high resolution, although with a narrow field of view.

CONCLUSION

Each modality has its strengths and weaknesses; no single technique will be suitable for all surgical procedures. Strict selection of modalities per cancer type and surgical requirements is required as well as combining techniques to find the optimal balance.

Correlative SEM SERS for quantitative analysis of dimer nanoparticles

A Raman microscope integrated with a scanning electron microscope was used to investigate plasmonic structures by correlative SEM-SERS analysis. The integrated Raman-SEM microscope combines high-resolution electron microscopy information with SERS signal enhancement from selected nanostructures with adsorbed Raman reporter molecules. Correlative analysis is performed for dimers of two gold nanospheres. Dimers were selected on the basis of SEM images from multi aggregate samples. The effect of the orientation of the dimer with respect to the polarization state of the laser light and the effect of the particle gap size on the Raman signal intensity is observed. Additionally, calculations are performed to simulate the electric near field enhancement. These simulations are based on the morphologies observed by electron microscopy. In this way the experiments are compared with the enhancement factor calculated with near field simulations and are subsequently used to quantify the SERS enhancement factor. Large differences between experimentally observed and calculated enhancement factors are regularly detected, a phenomenon caused by nanoscale differences between the real and 'simplified' simulated structures. Quantitative SERS experiments reveal the structure induced enhancement factor, ranging from ∼200 to ∼20 000, averaged over the full nanostructure surface. The results demonstrate correlative Raman-SEM microscopy for the quantitative analysis of plasmonic particles and structures, thus enabling a new analytical method in the field of SERS and plasmonics.

Observation of whispering gallery modes through electron beam-induced deposition

Surprisingly intense spectra of whispering gallery modes were observed in polymer microbeads after illumination with electrons in a scanning electron microscope and subsequent laser illumination and spectral analysis. It will be proposed that whispering gallery mode resonances became visible after local deposition of hydrocarbon material through electron beam-induced deposition. The illumination of deposited material with a near infrared laser generates a broad light spectrum, acting as a local "white light" source that couples, for favorable wavelengths, with the WGM sustained by the sphere. This facilitates a spectroscopic analysis of the WGM and provides the Q-factor and free spectral range for all investigated particles. The analysis by an integrated SEM and Raman micro-spectrometer offers a direct approach to the analysis of WGM resonators as they are, for instance, used in sensing.

The validation of a computer-adaptive test (CAT) for assessing health-related quality of life in children and adolescents in a clinical sample: study design, methods and first results of the Kids-CAT study

PURPOSE

Recently, we developed a computer-adaptive test (CAT) for assessing health-related quality of life (HRQoL) in children and adolescents: the Kids-CAT. It measures five generic HRQoL dimensions. The aims of this article were (1) to present the study design and (2) to investigate its psychometric properties in a clinical setting.

METHODS

The Kids-CAT study is a longitudinal prospective study with eight measurements over one year at two University Medical Centers in Germany. For validating the Kids-CAT, 270 consecutive 7- to 17-year-old patients with asthma (n = 52), diabetes (n = 182) or juvenile arthritis (n = 36) answered well-established HRQoL instruments (Pediatric Quality of Life Inventory™ (PedsQL), KIDSCREEN-27) and scales measuring related constructs (e.g., social support, self-efficacy). Measurement precision, test-retest reliability, convergent and discriminant validity were investigated.

RESULTS

The mean standard error of measurement ranged between .38 and .49 for the five dimensions, which equals a reliability between .86 and .76, respectively. The Kids-CAT measured most reliably in the lower HRQoL range. Convergent validity was supported by moderate to high correlations of the Kids-CAT dimensions with corresponding PedsQL dimensions ranging between .52 and .72. A lower correlation was found between the social dimensions of both instruments. Discriminant validity was confirmed by lower correlations with non-corresponding subscales of the PedsQL.

CONCLUSIONS

The Kids-CAT measures pediatric HRQoL reliably, particularly in lower areas of HRQoL. Its test-retest reliability should be re-investigated in future studies. The validity of the instrument was demonstrated. Overall, results suggest that the Kids-CAT is a promising candidate for detecting psychosocial needs in chronically ill children.

Implementation of the Kids-CAT in clinical settings: a newly developed computer-adaptive test to facilitate the assessment of patient-reported outcomes of children and adolescents in clinical practice in Germany

PURPOSE

To describe the implementation process of a computer-adaptive test (CAT) for measuring health-related quality of life (HRQoL) of children and adolescents in two pediatric clinics in Germany. The study focuses on the feasibility and user experience with the Kids-CAT, particularly the patients' experience with the tool and the pediatricians' experience with the Kids-CAT Report.

METHODS

The Kids-CAT was completed by 312 children and adolescents with asthma, diabetes or rheumatoid arthritis. The test was applied during four clinical visits over a 1-year period. A feedback report with the test results was made available to the pediatricians. To assess both feasibility and acceptability, a multimethod research design was used. To assess the patients' experience with the tool, the children and adolescents completed a questionnaire. To assess the clinicians' experience, two focus groups were conducted with eight pediatricians.

RESULTS

The children and adolescents indicated that the Kids-CAT was easy to complete. All pediatricians reported that the Kids-CAT was straightforward and easy to understand and integrate into clinical practice; they also expressed that routine implementation of the tool would be desirable and that the report was a valuable source of information, facilitating the assessment of self-reported HRQoL of their patients.

CONCLUSIONS

The Kids-CAT was considered an efficient and valuable tool for assessing HRQoL in children and adolescents. The Kids-CAT Report promises to be a useful adjunct to standard clinical care with the potential to improve patient-physician communication, enabling pediatricians to evaluate and monitor their young patients' self-reported HRQoL.

Contributed review: Review of integrated correlative light and electron microscopy

New developments in the field of microscopy enable to acquire increasing amounts of information from large sample areas and at an increased resolution. Depending on the nature of the technique, the information may reveal morphological, structural, chemical, and still other sample characteristics. In research fields, such as cell biology and materials science, there is an increasing demand to correlate these individual levels of information and in this way to obtain a better understanding of sample preparation and specific sample properties. To address this need, integrated systems were developed that combine nanometer resolution electron microscopes with optical microscopes, which produce chemically or label specific information through spectroscopy. The complementary information from electron microscopy and light microscopy presents an opportunity to investigate a broad range of sample properties in a correlated fashion. An important part of correlating the differences in information lies in bridging the different resolution and image contrast features. The trend to analyse samples using multiple correlated microscopes has resulted in a new research field. Current research is focused, for instance, on (a) the investigation of samples with nanometer scale distribution of inorganic and organic materials, (b) live cell analysis combined with electron microscopy, and (c) in situ spectroscopic and electron microscopy analysis of catalytic materials, but more areas will benefit from integrated correlative microscopy.

Label-free imaging and identification of typical cells of acute myeloid leukaemia and myelodysplastic syndrome by Raman microspectroscopy

Heamatopoietic cancer cells from patients were objectively and accurately recognized by high-resolution Raman imaging and their characteristic Raman spectra.

Epithelioid osteosarcoma of the scapula

Epithelioid and epithelial neoplasms of bone are rare. They include different epithelioid variants of vascular lesions, osteoblastoma, chondroblastoma and most importantly metastatic carcinoma. Up to now, only few cases of epithelioid osteosarcoma were described. In this case the authors report a 53-year-old patient presented with a medical history of chronic shoulder pain for 3 years. Magnetic resonance imaging (MRI and computed tomography (CT) showed a destructive, partially calcified osseous lesion of the scapula with expansion into the surrounding soft tissue, suggestive of a primary bone tumor. Histologically, the tumor consisted of epithelioid cells with expression of cytokeratine and the lesion was primarily diagnosed as metastatic carcinoma. With regard to the MRI morphology untypical for metastatic disease the histopathologic slides were re-evaluated and detection of tumor osteoid led to the diagnosis of epithelioid osteosarcoma. Chemotherapy was initiated, however follow-up imaging studies showed rapidly progressive disease of both primary tumor and lung metastases. In conclusion, epithelioid neoplasms of the bone are extremetumourly rare and must be distinguished from metastatic carcinoma. Despite the presence of cytokeratine positive cells a thorough histological evaluation is mandatory and osteoid detection is essential in order to establish the correct diagnosis and further treatment. Key words: osteosarcoma, epithelioid, aneurysmal bone cyst, chondrosarcoma, pathology, immunohistochemistry.

Blood lactate concentrations are mildly affected by mobile gas exchange measurements

We sought to investigate the effects of wearing a mobile respiratory gas analysis system during a treadmill test on blood lactate (bLa) concentrations and commonly applied bLa thresholds. A total of 16 recreational athletes (31±3 years, VO2max: 58±6 ml · min(-1) · kg(-1)) performed one multistage treadmill test with and one without gas exchange measurements (GEM and noGEM). The whole bLa curve, the lactate threshold (LT), the individual anaerobic thresholds according to Stegmann (IATSt) and Dickhuth (IATDi), and a fixed bLa concentration of 4 mmol ∙ l(-1) (OBLA) were evaluated. The bLa curve was shifted slightly leftward in GEM compared to noGEM (P<0.05), whereas the heart rate response was not different between conditions (P=0.89). There was no difference between GEM and noGEM for LT (2.61±0.34 vs. 2.64±0.39 m · s(-1), P=0.49) and IATSt (3.47±0.42 vs. 3.55±0.47 m · s(-1), P=0.12). However, IATDi (3.57±0.39 vs. 3.66±0.44 m · s(-1), P<0.01) and OBLA (3.85±0.46 vs. 3.96±0.47 m · s(-1), P<0.01) occurred at slower running velocities in GEM. The bLa response to treadmill tests is mildly affected by wearing a mobile gas analysis system. This also applies to bLa thresholds located at higher exercise intensities. While the magnitude of the effects is of little importance for recreational athletes, it might be relevant for elite athletes and scientific studies.

Tuning the Kondo effect in thin Au films by depositing a thin layer of Au on molecular spin-dopants

We report on the tuning of the Kondo effect in thin Au films containing a monolayer of cobalt(II) terpyridine complexes by altering the ligand structure around the Co(2+) ions by depositing a thin Au capping layer on top of the monolayer on Au by magnetron sputtering (more energetic) and e-beam evaporation (softer). We show that the Kondo effect is slightly enhanced with respect to that of the uncapped film when the cap is deposited by evaporation, and significantly enhanced when magnetron sputtering is used. The Kondo temperature (TK) increases from 3 to 4.2/6.2 K for the evaporated/sputtered caps. X-ray absorption spectroscopy and surface-enhanced Raman spectroscopy investigation showed that the organic ligands remain intact upon Au e-beam evaporation; however, sputtering inflicts significant change in the Co(2+) electronic environment. The location of the monolayer-on the surface or embedded in the film-has a small effect. However, the damage of Co-N bonds induced by sputtering has a drastic effect on the increase of the impurity-electron interaction. This opens up the way for tuning of the magnetic impurity states, e.g. spin quantum number, binding energy with respect to the host Fermi energy, and overlap via the ligand structure around the ions.

[Rotating physician in CHIR-Net. Evaluation of the curriculum]

BACKGROUND

Conduction of and participation in clinical trials is a major challenge for surgical departments especially as job performance in hospitals has increased immensely during the last few years due to economic aspects. Only 11.7 % of published clinical studies are randomized controlled trials. As more and more treatment procedures in medicine have an evidence-based design the aim must be to present randomized controlled trials with an evidence level 1 for an increasing number of surgical therapies. Since 2006 the German National Surgical Trial Network (CHIR-Net) has been established and funded by the Federal Ministry of Education and Research (BMBF) in order to promote the realization of clinical trials in surgery. Thus the basis for the execution of high quality clinical studies in surgery has been extended further. In the individual CHIR-Net centers clinical trials are planned, organized and supervised which requires extensive knowledge of prevalent international standards. Teaching them to rotating physicians is one of the tasks of CHIR-Net. Therefore, a special curriculum for physicians has been developed which is evaluated in this study.

MATERIALS AND METHODS

From December 2010 to March 2011 an online survey of physicians who had previously rotated in the CHIR-Net was conducted, starting from the Surgical Regional Center (CRZ) Witten-Herdecke/Cologne. A total of 19 partly open and partly closed questions concerning the person, training, duration of the rotation, the funding applied for and the generated scientific output were surveyed. In addition, the curriculum for physicians and rotation time was checked by means of 17 questions in an evaluation matrix.

RESULTS

In this article the results of the rotating physician evaluation are presented. The satisfaction of physicians with the training during the rotation is presented as well as an analysis of how many of the submitted publications were directly supported by CHIR-Net. It was also evaluated how many rotating physicians requested funding and what the type of funding was.

CONCLUSION

With the rotating physician model of CHIR-Net a working concept for the training of surgeons in clinical research and the realization of randomized surgical trials was established as a viable solution for the difficult situation of clinical research in the surgical disciplines with the double burden of research and clinical practice.

Cellular origin and diagnostic significance of high-fluorescent cells in cerebrospinal fluid detected by the XE-5000 hematology analyzer

INTRODUCTION

The Sysmex XE-5000 is a blood and body fluid analyzer able to differentiate cells into polymorphonuclear, mononuclear, and high-fluorescent cells (HFC). The identity of HFC in cerebrospinal fluid (CSF) has been uncertain; however, compatible with their high nucleic acid content, HFC could represent intrathecal tumor cells. Here, we studied the cellular origin and the diagnostic significance of HFC in CSF.

METHODS

Results of CSF examinations with the XE-5000 were analyzed in 65 CSF samples with and 126 CSF samples without tumor cells, as defined by manual microscopy of CSF cytospin preparations.

RESULTS

The XE-5000 detected HFC in 51 of 65 tumor cell-positive and in 33 of 126 tumor cell-negative CSF samples (sensitivity: 78.5%, specificity: 73.8%, positive likelihood ratio: 3.0, negative likelihood ratio: 0.29). The percentages of HFC and tumor cells in CSF samples correlated (r² = 0.41, P < 0.0001). Tumor cells escaped detection by the XE-5000 especially in CSF samples with a low percentage of tumor cells.

CONCLUSION

While this study identifies tumor cells as the predominant correlate of HFC in CSF, it suggests that measuring HFC is not an appropriate diagnostic test for intrathecal tumor cells. However, if HFC are incidentally detected in CSF, further evaluation by CSF microscopy seems mandatory.

A WBAN System for Ambulatory Monitoring of Physical Activity and Health Status: Applications and Challenges

Recent technological advances in sensors, low-power integrated circuits, and wireless communications have enabled the design of low-cost, miniature, lightweight, intelligent physiological sensor platforms that can be seamlessly integrated into a body area network for health monitoring. Wireless body area networks (WBANs) promise unobtrusive ambulatory health monitoring for extended periods of time and near real-time updates of patients' medical records through the Internet. A number of innovative systems for health monitoring have recently been proposed. However, they typically rely on custom communication protocols and hardware designs, lacking generality and flexibility. The lack of standard platforms, system software support, and standards makes these systems expensive. Bulky sensors, high price, and frequent battery changes are all likely to limit user compliance. To address some of these challenges, we prototyped a WBAN utilizing a common off-the-shelf wireless sensor platform with a ZigBee-compliant radio interface and an ultra low-power microcontroller. The standard platform interfaces to custom sensor boards that are equipped with accelerometers for motion monitoring and a bioamplifier for electrocardiogram or electromyogram monitoring. Software modules for on-board processing, communication, and network synchronization have been developed using the TinyOS operating system. Although the initial WBAN prototype targets ambulatory monitoring of user activity, the developed sensors can easily be adapted to monitor other physiological parameters. In this paper, we discuss initial results, implementation challenges, and the need for standardization in this dynamic and promising research field.

Quantitative detection of gold nanoparticles on individual, unstained cancer cells by scanning electron microscopy

Gold nanoparticles are rapidly emerging for use in biomedical applications. Characterization of the interaction and delivery of nanoparticles to cells through microscopy is important. Scanning electron microscopes have the intrinsic resolution to visualize gold nanoparticles on cells. A novel sample preparation protocol was developed to enable imaging of cells and gold nanoparticles with a conventional below lens scanning electron microscopes. The negative influence of 'charging' on the quality of scanning electron microscopes' images could be limited by deposition of biological cells on a conductive (gold) surface. The novel protocol enabled high-resolution scanning electron microscopes' imaging of small clusters and individual gold nanoparticles on uncoated cell surfaces. Gold nanoparticles could be counted on cancer cells with automated routines.

Intrathecal EBV antibodies are part of the polyspecific immune response in multiple sclerosis

OBJECTIVE

One mechanism underlying the link between multiple sclerosis (MS) and Epstein-Barr virus (EBV) might be a direct CNS infection. Viral CNS infections cause elevated antibody indices (AIs). Elevated EBV AIs were found in MS; however, patients with MS frequently show a polyspecific intrathecal immune response with elevated antiviral AIs. To discriminate whether elevated EBV AIs indicate a virus-driven or a polyspecific intrathecal immune response, we determined the intrathecal fraction of anti-EBV antibodies.

METHODS

The fraction of intrathecally synthesized EBV-specific immunoglobulin G (IgG) of the total intrathecally synthesized IgG (F(S) anti-EBV) was determined in 24 patients with a clinically isolated syndrome (CIS) or MS and 3 patients with cerebral posttransplantation lymphoproliferative disorder (PTLD), all of whom had elevated EBV AIs. F(S) anti-measles and AIs for measles, rubella, varicella zoster, and herpes simplex virus were measured as well. The prevalence of an elevated EBV AI was analyzed in another 36 patients with CIS.

RESULTS

Median F(S) anti-EBV in patients with CIS/MS was low (0.65%) and did not differ from F(S) anti-measles (0.9%). Median F(S) anti-EBV was about 40-fold higher in patients with cerebral PTLD than in patients with CIS/MS. All 24 patients with CIS/MS with an elevated EBV AI had at least one further elevated antiviral AI. Only 2 of 36 (5.6%) patients with CIS showed an intrathecal synthesis of anti-EBV antibodies.

CONCLUSIONS

Intrathecally produced anti-EBV antibodies are part of the polyspecific intrathecal immune response in CIS/MS and only rarely detectable in patients with CIS, both arguing against a direct CNS infection with EBV in patients with CIS/MS.

Optical and non-optical methods for detection and characterization of microparticles and exosomes

Microparticles and exosomes are cell-derived microvesicles present in body fluids that play a role in coagulation, inflammation, cellular homeostasis and survival, intercellular communication, and transport. Despite increasing scientific and clinical interest, no standard procedures are available for the isolation, detection and characterization of microparticles and exosomes, because their size is below the reach of conventional detection methods. Our objective is to give an overview of currently available and potentially applicable methods for optical and non-optical determination of the size, concentration, morphology, biochemical composition and cellular origin of microparticles and exosomes. The working principle of all methods is briefly discussed, as well as their applications and limitations based on the underlying physical parameters of the technique. For most methods, the expected size distribution for a given microvesicle population is determined. The explanations of the physical background and the outcomes of our calculations provide insights into the capabilities of each method and make a comparison possible between the discussed methods. In conclusion, several (combinations of) methods can detect clinically relevant properties of microparticles and exosomes. These methods should be further explored and validated by comparing measurement results so that accurate, reliable and fast solutions come within reach.

[Clinical research in orthopaedics--creation of a clinical trial unit in orthopaedics/trauma surgery]

AIM

The clinical trial is the link between research and medical practice and facilitates evidence-based therapies. There are specific difficulties to be faced when executing clinical trials related to surgical services (learning curve of the surgeon, blinding etc.). As a result, surgical randomised controlled clinical trials (RCT) are underrepresented in the total number of RCTs.

METHOD

To make it easier to implement surgical RCT, the Clinical Trial Unit for Orthopaedics and Trauma Surgery was established. Training of the supporting physicians was reached by rotations in the structures of CHIR-Net, a BMBF-funded network created to build up a region-wide surgical research infrastructure.

RESULT/CONCLUSION

Supported by the regional CHIR-Net Center and the regional Clinical Trial Center, a research institute was thus founded with the aim of contributing to a long-term improvement in clinical research in orthopaedics and trauma surgery.

Determinants of exercise-induced fat oxidation in obese women and men

Endurance training at an intensity eliciting maximal fat oxidation may have a beneficial effect on body weight and glucose metabolism in obese patients. However, the exercise intensity at which maximal fat oxidation occurs and the factors limiting fat oxidation are not well studied in this population. Obese, otherwise healthy men (n=38) and women (n=91) performed an incremental exercise test up to exhaustion on a cycle ergometer. Substrate oxidation was estimated using indirect calorimetry. Magnetic resonance tomography and spectroscopy were conducted to assess body fat distribution and intramyocellular fat content. We determined the exercise intensity at which maximal body fat oxidation occurs and assessed whether body composition, body fat distribution, intramyocellular fat content, or oxidative capacity predict exercise-induced fat oxidation. Maximal exercise-induced fat oxidation was 0.30+/-0.02 g/min in men and 0.23+/-0.01 g/min in women (p<0.05). Exercise intensity at the maximum fat oxidation was 42+/-2.2% VO (2 max) in men and 43+/-1.7% VO (2 max) in women. With multivariate analysis, exercise-induced fat oxidation was related to fat-free mass, percent fat mass, and oxidative capacity, but not to absolute fat mass, visceral fat, or intramyocellular fat content. We conclude that in obese subjects the capacity to oxidize fat during exercise appears to be limited by skeletal muscle mass and oxidative capacity rather than the availability of visceral or intramyocellular fat.

Interaction of oxazole yellow dyes with DNA studied with hybrid optical tweezers and fluorescence microscopy

We have integrated single molecule fluorescence microscopy imaging into an optical tweezers set-up and studied the force extension behavior of individual DNA molecules in the presence of various YOYO-1 and YO-PRO-1 concentrations. The fluorescence modality was used to record fluorescent images during the stretching and relaxation cycle. Force extension curves recorded in the presence of either dye did not show the overstretching transition that is characteristic for bare DNA. Using the modified wormlike chain model to curve-fit the force extension data revealed a contour length increase of 6% and 30%, respectively, in the presence of YO-PRO-1 and YOYO-1 at 100 nM. The fluorescence images recorded simultaneously showed that the number of bound dye molecules increased as the DNA molecule was stretched and decreased again as the force on the complex was lowered. The binding constants and binding site sizes for YO-PRO-1 and YOYO-1 were determined as a function of the force. The rate of YO-PRO-1 binding and unbinding was found to be 2 orders of magnitude larger than that for YOYO-1. A kinetic model is proposed to explain this observation.

Vibrational phase contrast microscopy by use of coherent anti-Stokes Raman scattering

In biological samples the resonant coherent anti-Stokes Raman scattering signal of less abundant constituents can be overwhelmed by the nonresonant background, preventing detection of those molecules. We demonstrate a method to obtain the phase of the oscillators in the focal volume that allows discrimination of those hidden molecules. The phase is measured with respect to the local excitation fields using a cascaded phase-preserving chain. It is measured point-by-point and takes into account refractive index changes in the sample, phase curvature over the field-of-view, and interferometric instabilities. The detection of the phase of the vibrational motion can be regarded as a vibrational extension of the linear (refractive index) phase contrast microscopy introduced by Zernike around 1933.