Micropatterning as a tool to identify regulatory triggers and kinetics of actin-mediated endothelial mechanosensing

Developmental processes, such as angiogenesis, are associated with a constant remodeling of the actin cytoskeleton in response to different mechanical stimuli. The mechanosensitive transcription factors MRTF-A (MKL1) and YAP (also known as YAP1) are important mediators of this challenging adaptation process. However, it is as yet unknown whether both pathways respond in an identical or in a divergent manner to a given microenvironmental guidance cue. Here, we use a micropatterning approach to dissect single aspects of cellular behavior in a spatiotemporally controllable setting. Using the exemplary process of angiogenesis, we show that cell-cell contacts and adhesive surface area are shared regulatory parameters of MRTF and YAP on rigid 2D surfaces. By analyzing MRTF and YAP under laminar flow conditions and during cell migration on dumbbell-shaped microstructures, we demonstrate that they exhibit different translocation kinetics. In conclusion, our work promotes the application of micropatterning techniques as a cell biological tool to study mechanosensitive signaling in the context of angiogenesis.

Assessment of tryptophan metabolism and signs of depression in individuals with carbohydrate malabsorption

This prospective cross-sectional study aimed to investigate the potential association between primary-adult lactose malabsorption, fructose malabsorption, tryptophan (TRP) metabolism and the presence of depressive signs. Overall 251 patients, who were referred for lactase gene C/T_-13910 polymorphism genotyping and fructose hydrogen/methane breath testing, were included. All participants filled out the Beck Depression Inventory (BDI II). Serum concentrations of tryptophan (TRP), kynurenine (KYN), kynuric acid (KYNA), and TRP competing amino acids (leucine, isoleucine, valine, phenylalanine, tyrosine) were measured by high-pressure liquid-chromatography. Logistic regression analysis was performed with lactose malabsorption, fructose malabsorption and all potential biomarkers of TRP metabolism to assess the effect on signs of depression, defined as a BDI II score > 13. Primary-adult lactose malabsorption and fructose malabsorption was detected in 65 (25.90%) and 65 (25.90%) patients, respectively. Fructose malabsorption was significantly associated with BDI II score, whereas no such relationship was found for lactose malabsorption. Serum levels of TRP and TRP metabolites were no predictors of depression. The authors suggest to conduct further prospective longitudinal studies in order to get further insight of associations between carbohydrate malabsorption, biomarkers and mood disorders.

Effect fusion using model-based clustering

Abstract:

In social and economic studies many of the collected variables are measured on a nominal scale, often with a large number of categories. The definition of categories can be ambiguous and different classification schemes using either a finer or a coarser grid are possible. Categorization has an impact when such a variable is included as covariate in a regression model: a too fine grid will result in imprecise estimates of the corresponding effects, whereas with a too coarse grid important effects will be missed, resulting in biased effect estimates and poor predictive performance.

To achieve an automatic grouping of the levels of a categorical covariate with essentially the same effect, we adopt a Bayesian approach and specify the prior on the level effects as a location mixture of spiky Normal components. Model-based clustering of the effects during MCMC sampling allows to simultaneously detect categories which have essentially the same effect size and identify variables with no effect at all. Fusion of level effects is induced by a prior on the mixture weights which encourages empty components. The properties of this approach are investigated in simulation studies. Finally, the method is applied to analyse effects of high-dimensional categorical predictors on income in Austria.

Studies of Gallium Accumulation in Inflammatory Lesions

The kinetics of 67Ga accumulation in experimental inflammatory exudates were studied. In six rabbits with 5. aureus induced abscesses, serial samples of exudate and blood were obtained at 1, 2, 4, 24 and 48 hrs after intravenous injection of 67Ga. The accumulation of 67Ga in the inflammatory exudate was slow with an accumulation half-time of 5.5 hrs. The concentration of 67Ga in the abscesses approached that of blood 48 hrs after injection.

Analysis of the distribution of 67Ga in the inflammatory exudate revealed that the portion of 67Ga in the cellular fraction (1,600 xg pellet) correlated best with the number of non-viable polymorphonuclear leukocytes (PMN) (r = 0.81). Its correlation with total number of PMN and bacteria was r = 0.69 and r = 0.35, respectively. Autoradiographie studies confirmed that the majority of 67Ga in the cellular fraction of the exudate was associated with non-viable PMN’s.

Abdominal Pseudocysts and Peritoneal Catheter Revisions: Surgical Long-Term Results in Pediatric Hydrocephalus

OBJECTIVE

An abdominal pseudocyst (APC) is a distal catheter site-specific failure in patients treated with ventriculoperitoneal shunts. Few studies with more than 10 patients have been reported. The aim of this study was to analyze causes of peritoneal catheter revisions with special emphasis on revisions because of an APC.

METHODS

Pediatric patients with first shunt operation between 1982 and 1992 were included, and time, cause, and modality of peritoneal catheter revision were determined retrospectively.

RESULTS

One hundred thirty-eight patients were treated for hydrocephalus, and 112 patients received a peritoneal catheter during the follow-up. An APC was diagnosed in 14 (12.5%) patients, and 28 revisions were needed for its treatment. The rate of shunt infection in patients with APC was 50%, but bacterial examination of the pseudofluid culture revealed infection in only 3 patients. Age at first surgical procedure, type of first surgical procedure, and etiology of hydrocephalus were not associated with APC diagnosis. APC recurred in 4 patients. These patients had a catheter repositioning directly into the peritoneum as first surgical treatment. No recurrences were observed in patients with shunt externalization or replacement of the peritoneal catheter.

CONCLUSIONS

An APC is a major long-term complication after ventriculoperitoneal shunt treatment. Although a sterile inflammatory response cannot be excluded completely, our results favor the hypothesis of low-level shunt infection. In both cases, the surgical consequences are the same. An infected APC should be treated as a shunt infection. Uninfected patients can be treated with shunt externalization and replacement of only the peritoneal catheter.

Molecular analyses on Neospora caninum-triggered NETosis in the caprine system

Neospora caninum is an obligate intracellular protozoan parasite causing serious reproductive disorders in large and small ruminants worldwide. Polymorphonuclear neutrophils (PMN) react against multiple invading pathogens through different mechanisms including the release of neutrophil extracellular traps (NETs). Here, in vitro interactions of caprine PMN and N. caninum tachyzoites were studied. Scanning electron microscopic- and immunofluorescence-analyses demonstrated that caprine PMN undergo NETosis upon contact with tachyzoites of N. caninum, extruding filaments that entrap parasites. Detailed co-localization studies of N. caninum tachyzoite-induced NETs revealed the presence of PMN-derived DNA being decorated with histones (H1, H2A/H2B, H3,H4) and neutrophil elastase (NE) corroborating the molecular characteristics of classical mammalian NETs. As a new result for parasite-induced NETosis, we identified pentraxin and cathepsin B in N. caninum-triggered NETs. Nonetheless, functional inhibition assays revealed that during caprine NET formation triggered by N. caninum different molecular signaling pathways are induced, when compared to other apicomplexan parasites or host species. As such, N. caninum-induced NETosis appears to be influenced by MPO but independent of NADPH oxidase, SOCE, ERK1/2 and p38 MAPK activities. Furthermore, the inhibition of PMN autophagy via blockage of the PI3K-mediated signaling pathway failed to influence tachyzoite-induced NETosis. Since N. caninum-tachyzoites induced caprine NETosis, this effector mechanism should be considered as an early host immune response during acute caprine neosporosis.

Abstract P4-18-05: Male breast cancer— infusing a little blue into the sea of pink

Male breast cancer (MBC) is a rare disease dominated by a sea of pink. Issues faced by men with this disease include delayed diagnosis, lack of male-specific information, stigma about having a "female disease" and often under-treatment.

MBC is often treated as a female breast cancer but differences between the two are starting to emerge. Men are often older at diagnosis and sometimes considered "too old" for more aggressive treatments such as chemotherapy. Drugs such as aromatase inhibitors may not be as effective in men as in women but are often prescribed. Drugs such as tamoxifen can cause side-effects such as weight gain, hot flushes, loss of libido and impotence.

Support for patients with MBC is less advanced than that for female breast cancer. A Man's Pink, a MBC advocacy organization, mission is to promote MBC awareness, increase early detection, optimize and increase the survival rates for men diagnosed with breast cancer. Male Breast Cancer: Taking Control (BC Publishing, Boyages, 2015) empowers patients to understand their diagnosis and treatment.

Apart from incidence data, prognosis and treatment options, this talk will focus on how a website (www.malebreastcancer.ca) dedicated to MBC can help dismiss some of the myths and help overcome stigmata for men facing difficulties at diagnosis, treatment and recovery.

Our goal is to promote awareness to assist with earlier diagnosis and treatment to improve survival rates and the journey for men in their battle with breast cancer.

Citation Format: Wagner H, Boyages J. Male breast cancer— infusing a little blue into the sea of pink [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 P4-18-05.

Development and validation of the Salzburg COPD-screening questionnaire (SCSQ): a questionnaire development and validation study

Chronic obstructive pulmonary disease prevalence rates are still high. However, the majority of subjects are not diagnosed. Strategies have to be implemented to overcome the problem of under-diagnosis. Questionnaires could be used to pre-select subjects for spirometry and thereby help reducing under-diagnosis. We report a brief, simple, self-administrable and validated chronic obstructive pulmonary disease questionnaire to increase the pre-test probability for chronic obstructive pulmonary disease diagnosis in subjects undergoing confirmatory spirometry. In 2005, we completed the Austrian Burden of Obstructive Lung Disease-study in 1258 subjects aged >40 years. Post-bronchodilator spirometry was performed, and non-reversible airflow limitation defined by FEV1/FVC ratio below the lower limit of normal. Questions from the Salzburg chronic obstructive pulmonary disease screening-questionnaire were selected using a logistic regression model, and risk scores were based on regression-coefficients. A training sub-sample (n = 800) was used to create the score, and a test sub-sample (n = 458) was used to test it. In 2008, an external validation study was done, using the same protocol in 775 patients from primary care. The Salzburg chronic obstructive pulmonary disease screening questionnaire was composed of items related to "breathing problems", "wheeze", "cough", "limitation of physical activity", and "smoking". At the >=2 points cut-off of the Salzburg chronic obstructive pulmonary disease screening questionnaire, sensitivity was 69.1% [95%CI: 56.6%; 79.5%], specificity 60.0% [95%CI: 54.9%; 64.9%], the positive predictive value 23.2% [95%CI: 17.7%; 29.7%] and the negative predictive value 91.8% [95%CI: 87.5%; 95.7%] to detect post bronchodilator airflow limitation. The external validation study in primary care confirmed these findings. The Salzburg chronic obstructive pulmonary disease screening questionnaire was derived from the highly standardized Burden of Obstructive Lung Disease study. This validated and easy to use questionnaire can help to increase the efficiency of chronic obstructive pulmonary disease case-finding.

CHRONIC OBSTRUCTIVE PULMONARY DISEASE

QUESTIONNAIRE FOR PRE-SCREENING POTENTIAL SUFFERERS: Scientists in Austria have developed a brief, simple questionnaire to identify patients likely to have early-stage chronic lung disease. Chronic obstructive pulmonary disease (COPD) is notoriously difficult to diagnose, and the condition often causes irreversible lung damage before it is identified. Finding a simple, cost-effective method of pre-screening patients with suspected early-stage COPD could potentially improve treatment responses and limit the burden of extensive lung function ('spirometry') tests on health services. Gertraud Weiss at Paracelsus Medical University, Austria, and co-workers have developed and validated an easy-to-use, self-administered questionnaire that could prove effective for pre-screening patients. The team trialed the five-point Salzburg COPD-screening questionnaire on 1258 patients. Patients scoring 2 points or above on the questionnaire underwent spirometry tests. The questionnaire seems to provide a sensitive and cost-effective way of pre-selecting patients for spirometry referral.

Long-term mortality rates in pediatric hydrocephalus-a retrospective single-center study

PURPOSE

Very long-term follow-up and outcome are rare for pediatric patients with hydrocephalus and shunt operations. The aim of this study was to determine the long-term mortality rates in these patients.

METHODS

Pediatric patients with first shunt operation between 1982 and 1992 were included. For each patient, time and cause of death were determined. Further, patients with first operation from 1982 to 1987 were compared to those first operated from 1988 to 1992.

RESULTS

One-hundred thirty-seven patients were included. Etiologies of hydrocephalus were intraventricular hemorrhage (31.4 %), meningomyelocele (25.5 %), postinfectious (11.7 %), congenital (10.2 %), posterior fossa cyst (8.8 %), aqueductal stenosis (8 %), and others (4.4 %). Overall, 53 patients (38.7 %) died. The percentage of patients surviving 1, 2, 10, and 20 years after first operation were 82.6, 73.6, 69.4, and 65.3 %, respectively. In 23 patients, the cause of death was related to shunt treatment: shunt infection was diagnosed in 18 and acute shunt dysfunction in 5 patients. Mortality was considerably higher for patients with their first operation in time period 1982-1987 compared to time period 1988-1992 (51 versus 25 %). The reduction of mortality was mainly due to an increased survival after shunt infection. Eighty-seven patients survived more than 20 years after initial shunt operation. Of those long-term survivors, three (3.4 %) patients died 22-24 years after first operation.

CONCLUSION

Mortality in hydrocephalic pediatric patients is high especially in the first postoperative years but is even significant in adult patients with pediatric hydrocephalus. As deaths occur even after 20 years, routine follow-up of long-term survivors remains necessary.

Lama glama αS1-casein: Identification of new polymorphisms in the CSN1S1 gene

South American camelids have been poorly genetically investigated and little information is available in llamas (Lama glama) regarding the diversity of the caseins at the protein and gene level. Exon skipping and duplication events previously reported in the α_S1-casein gene (CSN1S1) led us to investigate the genetic variability at this locus. Seventy-two positive clones for the α_S1-casein transcripts were analyzed and randomly sequenced. The comparative analysis of the sequences revealed 2 transitions, c.366A>G and c.690T>C, at the 10th nucleotide of exon 12 and 94 bp of exon 19, respectively. These SNP are responsible for 2 amino acid changes, Ile→Val in position 86 and Tyr→His in position 194 of the mature protein. Both polymorphisms clarify the genetic events behind the protein variants A and B. This result was confirmed by isoelectric focusing analysis of llama milk samples. Quick methods based on PCR-RFLP and allele-specific PCR were set up for allelic discrimination in a population of 128 animals. Based on genotyping results, 4 haplotypes were observed and the estimated frequencies indicated B as the most common haplotype (0.629) in the investigated population. These data add knowledge to the genetic variability of a species little investigated, and open opportunity for new investigation in the field of milk protein for South American camelids, including the possibility, in the future, to select alleles with favorable characteristics.

Simulation Studies for Complex Sampling Designs

Choosing the appropriate variance estimation method in complex surveys is a difficult task since there exist a variety of techniques which usually cannot be compared mathematically. A relatively easy way to accomplish such a comparison is on the basis of simulation studies. Though simulation studies are widely used in statistics, they are not a standard tool for investigating properties of estimators in complex survey sampling designs. In this paper we describe the setup for a simulation study according to the sampling plan of the Austrian Microcensus (AMC), used 1994–2003 which is an example for a very complex sampling plan. To illustrate the proceeding we conducted a simulation study comparing basic variance estimators. Results of the study reveal the extent to which simple variance estimators may underestimate the true sampling error in close to reality situations.

Book Reviews

Die Industriestatistik Europas im Umbruch. (M. Müller)Statistik. DerWeg zur Datenanalyse. (L. Fahrmeir, R. Künstler, I. Pigeot, G. Tutz)Einführung in die Stochastik. (R.K.W. Viertl)Probability Theory III. (Y.V. Prokhorov, A.N. Shiryaev)Functional Data Analysis. (J.O. Ramsay, B.W. Silverman)Business Analysis Using Regression. (D.P. Foster, R.A. Stine, R.P. Waterman)Applied Regression Analysis. A Research Tool. (J.O Rawlings , S.G. Pantula, D.A.Dickey )Econometric Analysis of Count Data. (R. Winkelmann)MartingaleMethodes in FinancialModelling. Theory and Applications. (M.Musiela,M. Rutkowski)Conference on Statistical Science Honouring the Bicentennial of Stefano Franscini’sBirth. (C.A.G. Malaguerra, St. Morgenthaler, E.M.D. Ronchetti)

Identifikation von Kovariableneinflüssen in der Füllungstherapie

Um Informationen über die Haltbarkeit von Zahnfüllungen zu erhalten und den Einfluss verschiedener Faktoren zu untersuchen, wurden verschiedene statistische Analysen durchgeführt. Dafür standen in Oberösterreich Daten von rund 3.4 Millionen Zahnfüllungen aus den Jahren 1994 bis 2002 zur Verfügung. Neben einer Schätzung der Überlebensfunktion bzw. der Ausfallrate, wurde der Einfluss verschiedener Kovariablen auf die Lebensdauer der Füllungen in einem Cox-Modell geschätzt. Die im Verhältnis zur vorliegenden Datenmenge geringe Zahl von Kovariablen, legt es nahe, dass die Daten auch unbeobachtete Heterogenität enthalten. Von Interesse ist dabei insbesondere, ob diese auf Effekte der Leistungserbringer, d.h. der behandelnden Ärzte zurückgeführt werden können. Diese Effekte werden durch ein Gamma-Shared-Frailty-Modell geschätzt. Die Ergebnisse führen zu Vorschl ägen einer differenzierteren Honorierung der Füllungstherapie.

Comparing Spike and Slab Priors for Bayesian Variable Selection

An important task in building regression models is to decide which regressors should be included in the final model. In a Bayesian approach, variable selection can be performed using mixture priors with a spike and a slab component for the effects subject to selection. As the spike is concentrated at zero, variable selection is based on the probability of assigning the corresponding regression effect to the slab component. These posterior inclusion probabilities can be determined by MCMC sampling. In this paper we compare the MCMC implementations for several spike and slab priors with regard to posterior inclusion probabilities and their sampling efficiency for simulated data. Further, we investigate posterior inclusion probabilities analytically for different slabs in two simple settings. Application of variable selection with spike and slab priors is illustrated on a data set of psychiatric patients where the goal is to identify covariates affecting metabolism.

Sparse Bayesian modelling of underreported count data

We consider Bayesian inference for regression models of count data subject to underreporting. For the data generating process of counts as well as the fallible reporting process a joint model is specified, where the outcomes in both processes are related to a set of potential covariates. Identification of the joint model is achieved by additional information provided through validation data and incorporation of variable selection. For posterior inference we propose a convenient Markov chain Monte Carlo (MCMC) sampling scheme which relies on data augmentation and auxiliary mixture sampling techniques for this two-part model. Performance of the method is illustrated for simulated data and applied to analyse real data, collected to estimate risk of cervical cancer death.