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Traditionally, dose-finding process for oncology compound is carried out in phase I dose escalation study and is driven by safety in order to find maximum tolerated dose (MTD). However, with the recent paradigm shift from cytotoxic drugs to new generation of targeted therapies and immuno-oncology therapies, it may be difficult or unnecessary to identify the MTD because of the possible non-monotonic dose–response curves, and efficacy data should be incorporated into the dose-finding process. In this article, we have proposed efficacy-driven dose-finding designs with a safety-driven warm-up phase. Both local investigation and adaptive randomization using the framework of double-sided isotonic regression are investigated. Simulation studies are used to compare the proposed design to the original double-sided isotonic design. The results show that a safety-driven warm-up phase at the beginning can significantly improve the performance of double-sided isotonic regression, and both local investigation and adaptive randomization have good operating characteristics for finding the best dose/dose range under different tested scenarios.

The Multiple Comparison Procedure and Modelling (MCPMod) approach has been shown to be a powerful statistical tool that can significantly improve the design and analysis of dose finding studies under model uncertainty. Due to its frequentist nature, however, it is difficult to incorporate into MCPMod information from historical trials on the same drug. Recently, a Bayesian version of MCPMod has been introduced by Fleischer et al. (2022) to resolve this issue, which is particularly tailored to the situation where there is information about the placebo dose group from historical trials. In practice, information may also be available on active dose groups from early phase trials, e.g., a dose escalation trial and a preceding small Proof of Concept trial with only a placebo and a high dose. To address this issue, we introduce a Bayesian hierarchical framework capable of incorporating historical information about both placebo and active dose groups with the flexibility of modelling both prognostic and predictive between-trial heterogeneity. Our method is particularly useful in the situation where the effect sizes of two trials are different. Our goal is to reduce the necessary sample size in the dose finding trial while maintaining its target power.

Multiple comparison procedures and modeling (MCPMod) has established itself as a method for dose-finding under model uncertainty. A downside of MCPMod is that due to its frequentist nature in particular with respect to the multiple comparison part it is tough to incorporate historical information in a systematic fashion. A typical situation where such historical information is available is existing data for the placebo group from previous trials. There are multiple Bayesian concepts for integrating historical data in a systematic and even dynamic fashion like the meta-analytic prior approach. In this article, we define Bayesian MCPMod (BMCPMod) that is build upon these two aspects. BMCPMod is able to mimic the results of the classical MCPMod for non-informative priors. At the same time, it allows for the inclusion of historical data in a systematic fashion. After the definition of BMCPMod related characteristics for a Bayesian approach similar to the MCP-testing part are derived. The BMCPMod is compared to classical MCPMod/non-informative priors via simulations. Aspects of mixture priors, optimal contrast vectors, and impact of allocation ratios are discussed and an example for designing a BMPCMod trial is given.

After exploratory drug development, companies face the decision whether to initiate confirmatory trials based on limited efficacy information. This proof-of-concept decision is typically performed after a Phase II trial studying a novel treatment versus either placebo or an active comparator. The article aims to optimize the design of such a proof-of-concept trial with respect to decision making. We incorporate historical information and develop pre-specified decision criteria accounting for the uncertainty of the observed treatment effect. We optimize these criteria based on sensitivity and specificity, given the historical information. Specifically, time-to-event data are considered in a randomized 2-arm trial with additional prior information on the control treatment. The proof-of-concept criterion uses treatment effect size, rather than significance. Criteria are defined on the posterior distribution of the hazard ratio given the Phase II data and the historical control information. Event times are exponentially modeled within groups, allowing for group-specific conjugate prior-to-posterior calculation. While a non-informative prior is placed on the investigational treatment, the control prior is constructed via the meta-analytic-predictive approach. The design parameters including sample size and allocation ratio are then optimized, maximizing the probability of taking the right decision. The approach is illustrated with an example in lung cancer.

A drug is defined as highly variable if its intra-individual coefficient of variation (CV) is greater than or equal to 30%. In such a case, bioequivalence may be assessed by means of methods that take the (high) variability into account. The Scaled Average Bioequivalence (SABE) approach is such a procedure and represents the recommendations of FDA. The aim of this investigation is to compare the performance characteristics of classical group sequential designs (GSD) and fixed design settings for three-period crossover bioequivalence studies with highly variable drugs, where the SABE procedure is utilized. Monte Carlo simulations were performed to assess type I error rate, power, and average sample size for GSDs with Pocock’s and O’Brien-Fleming’s stopping rules and various timings of the interim analysis and for fixed design settings. Based on our investigated scenarios, the GSDs show comparable properties with regard to power and type I error rate as compared to the corresponding fixed designs. However, due to an advantage in average sample size, the most appealing design is Pocock’s approach with interim analysis after 50% information fraction. Due to their favorable performance characteristics, two-stage GSDs are an appealing alternative to fixed sample designs when assessing bioequivalence in highly variable drugs.

In the present study, 53 cases of squamous cell carcinomas of the head and neck were characterized by a quantitative histological texture analysis based on principles of spatial statistics. A planar tessellation of the epithelial tumour component was generated by a skeletonization algorithm. The size distribution of the virtual cells of this planar tessellation, and the size distribution of the profiles of the tumour cell nuclei were estimated in terms of area and boundary length. The intensity, the reduced second moment function (K-function) and the pair correlation function of the point process of the centroids of the profiles of the tumour cell nuclei were also estimated. For both purposes, it is necessary to correct for edge effects, which we consider in this paper in some detail. Specifically, the point patterns of the tumour cell nuclei were considered as realizations of a point process, where the points exist only in the epithelial tumour component (the permitted phase) and not in the stroma (the forbidden phase). The methods allow to characterize each individual tumour by a series of summary statistics. The total set of cases was then partitioned into two groups: 19 cases without lymph node metastases (pN0), and 34 nodal positive cases (pN1 or pN2). Statistical analysis showed no significant differences between the intensities, the mean K-functions and the mean pair correlation functions of the tumour cell nucleus profiles of the two groups. However, there were some significant differences between the sizes of the virtual cells and of the nucleus profiles of the nodal negative cases as compared to the nodal positive cases. In a logistic regression analysis, one of the quantitative nuclear size variables (mean nuclear area) was found to be a significant predictor of lymph node metastasis, in addition to tumour stage. The study shows the potential of methods of spatial statistics for objective quantitative grading of squamous cell carcinomas of the head and neck, and provides an example for modelling histological point patterns as realizations of planar point processes occupying a reference phase which is only a partial component of the total tissue.

This paper deals with the estimation of the intensity of a planar point process on the basis of a single point pattern, observed in a rectangular window. If the model assumptions of stationarity and isotropy hold, the method of block bootstrapping can be used to estimate the intensity of the process with confidence bounds. The results of two variants of block bootstrapping are compared with a parametric approximation based on the assumption of a Gaussian distribution of the numbers of points in deterministic subwindows of the original pattern. The studies were performed on patterns obtained by simulation of well-known point process models (Poisson process, two Matern cluster processes, Matern hardcore process, Strauss hardcore process). They were also performed on real histopathological data (point patterns of capillary profiles of 12 cases of prostatic cancer). The methods are presented as worked examples on two cases, where we illustrate their use as a check on stationarity (homogeneity) of a point process with respect to different fields of vision. The paper concludes with various methodological discussions and suggests possible extensions of the block bootstrap approach to other fields of spatial statistics.

Background: BI 2536, a novel Polo-like kinase 1 inhibitor, was assessed in patients with unresectable advanced exocrine adenocarcinoma of the pancreas. Methods: The study employed a two-stage design. Randomised first-line patients received BI 2536 200 mg on day 1 (n=43) or 60 mg on days 1-3 (n=43) every 21 days. Recruitment of second-line patients was planned for a second stage dependent on an interim analysis demonstrating ≥2 responses in the first 18 evaluable patients following 12 weeks of treatment and/or tumour control ≥12 weeks in 5 patients per schedule. Primary end point was objective response rate (ORR). Results: By independent review, ORR was 2.3% (all partial) and 24.4% had stable disease as confirmed best response. The second stage was not initiated. Median overall and progression-free survivals were 149 (95% confidence interval (CI), 91-307) and 46 days (95% CI, 44-56). Most common drug-related adverse events were neutropenia (37.2%), leukopenia (29.1%), fatigue (29.1%) and nausea (22.1%); most common grade 3/4-related events were neutropenia (36.0%), leukopenia (27.9%) and thrombocytopenia (8.1%). Conclusion: Given the low ORR and poor survival, further development of BI 2536 monotherapy is not warranted in this population. © 2012 Cancer Research UK All rights reserved.

A reliable determination of progression is of key importance in determining progression-free survival in oncology trials. An independent review of tumour assessments made by investigators is often implemented with the aim of reducing a possible bias. Often, the independent review is performed in a prespecified but retrospective fashion by reviewing a patient after all assessments have been performed. It has been discussed that this mechanism can lead to informative censoring with respect to independent review. This is caused by the fact that often no further assessments are available after the investigator has declared the patient to be progressive, possibly leading to a considerable amount of patients being judged progressive by the investigator and being censored by independent review. We introduce and investigate a model for the error in assessment with the aim of quantifying the bias in independent review. The model is based on single error probabilities at each assessment time-point that are independent from each other but dependent on the time to the true progression time-point. The bias introduced for the independent review is described and quantified. We show that the investigator assessments of progression can lead to less bias for progression-free survival than the results for independent review. Results show that a within-arm discordance rate is not necessarily correlated with the bias in independent review. Finally, we propose an approach for a sensitivity analysis that is a useful tool to sandwich the true underlying distribution by the results for independent review itself and the described sensitivity analysis.

We consider a spatial stochastic model for telecommunication networks, the stochastic subscriber line model, and we investigate the distribution of the typical shortest path length between network components. Therefore, we derive a representation formula for the probability density of this distribution which is based on functionals of the so-called typical serving zone. Using this formula, we construct an estimator for the density of the typical shortest path length and we analyze the statistical properties of this estimator. Moreover, we introduce new simulation algorithms for the typical serving zone which are used in a numerical study in order to estimate the density and moments of the typical shortest path length for different specific models.

Among the surrogate endpoints for overall survival (OS) in oncology trials, progression-free survival (PFS) is more and more taking the leading role. Although there have been some empirical investigations on the dependence structure between OS and PFS (in particular between the median OS and the median PFS), statistical models are almost non-existing. This paper aims at filling this gap by introducing an easy-to-handle model based on exponential time-to-event distributions that describe the dependence structure between OS and PFS. Based on this model, explicit formulae for individual correlations are derived together with a lower bound for the correlation of OS and PFS, which is given by the fraction of the two medians for OS and PFS. Two methods on how to estimate the parameter of the model from real data are discussed. One method is based on a maximum-likelihood estimator whereas the other method uses a plug-in approach. Three examples from non-small cell lung cancer are considered. In the first example, the parameters of the model are determined and the estimated survival curce is compared with the observed one. The second example explains how to obtain sample size estimates for OS based on assumptions on median PFS and OS. Finally, the third example provides a way of modelling and quantifying confounding effects that might explain a levelling of differences in OS although a difference in PFS is observed.

The aim of the paper is to apply point processes to root data modelling. We propose a new approach to parametric inference when the data are inhomogeneous replicated marked point patterns. We generalize Geyer's saturation point process to a model, which combines inhomogeneity, marks and interaction between the marked points. Furthermore, the inhomogeneity influences the definition of the neighbourhood of points. Using the maximum pseudolikelihood method, this model is then fitted to root data from mixed stands of Norway spruce (Picea abies (L.) Karst.) and European beech (Fagus sylvatica L.) to quantify the degree of root aggregation in such mixed stands. According to the analysis there is no evidence that the two root systems are not independent.

We consider stationary Poisson–Voronoi tessellations (PVT) in the Euclidean plane and study the properties of Voronoi tessellations induced by linear Poisson processes on the edges of the PVT. We are especially interested in simulation algorithms for the typical cell. Two different simulation algorithms are introduced. The first algorithm directly simulates the typical cell, whereas the second algorithm simulates cells from which distributional properties of the typical cell can be obtained. This second algorithm can also be used for simulating the typical cell of other Cox–Voronoi tessellations. The implementation of both algorithms is tested for their correctness using random software tests. Then different cell characteristics are studied by simulation and compared with the typical cell of PVT and Cox–Voronoi tessellations based on linear Poisson processes on the lines of Poisson line processes. Our results can be applied, for example, in the analysis of telecommunication networks and vesicle paths on c...

Keratin intermediate filament networks are part of the cytoskeleton in epithelial cells. They were found to regulate viscoelastic properties and motility of cancer cells. Due to unique biochemical properties of keratin polymers, the knowledge of the mechanisms controlling keratin network formation is incomplete. A combination of deterministic and stochastic modeling techniques can be a valuable source of information since they can describe known mechanisms of network evolution while reflecting the uncertainty with respect to a variety of molecular events. We applied the concept of piecewise-deterministic Markov processes to the modeling of keratin network formation with high spatiotemporal resolution. The deterministic component describes the diffusion-driven evolution of a pool of soluble keratin filament precursors fueling various network formation processes. Instants of network formation events are determined by a stochastic point process on the time axis. A probability distribution controlled by model parameters exercises control over the frequency of different mechanisms of network formation to be triggered. Locations of the network formation events are assigned dependent on the spatial distribution of the soluble pool of filament precursors. Based on this modeling approach, simulation studies revealed that the architecture of keratin networks mostly depends on the balance between filament elongation and branching processes. The spatial distribution of network mesh size, which strongly influences the mechanical characteristics of filament networks, is modulated by lateral annealing processes. This mechanism which is a specific feature of intermediate filament networks appears to be a major and fast regulator of cell mechanics.

We consider modulated Poisson--Voronoi tessellations, intended as models for telecommunication networks on a nationwide scale. By introducing an algorithm for the simulation of the typical cell of the latter tessellation, we lay the mathematical foundation for such a global analysis. A modulated Poisson--Voronoi tessellation has an intensity which is spatially variable and, hence, is able to provide a broad spectrum of model scenarios. Nevertheless, the considered tessellation model is stationary and we consider the case where the modulation is generated by a Boolean germ-grain model with circular grains. These circular grains may either have a deterministic or random but bounded radius. Furthermore, based on the introduced simulation algorithm for the typical cell and on Neveu's exchange formula for Palm probability measures, we show how to estimate the mean distance from a randomly chosen location to its nearest Voronoi cell nucleus. The latter distance is interpreted as an important basic cost characteristic in telecommunication networks, especially for the computation of more sophisticated functionals later on. Said location is chosen at random among the points of another modulated Poisson process where the modulation is generated by the same Boolean model as for the nuclei. The case of a completely random placement for the considered location is thereby included as a special case. The estimation of the cost functional is performed in a way such that a simulation of the location placement is not necessary. Test methods for the correctness of the algorithm based on tests for random software are briefly discussed. Numerical examples are provided for characteristics of the typical cell as well as for the cost functional. We conclude with some remarks about extensions and modifications of the model regarded in this paper, like modulated Poisson--Delaunay tessellations.

The relative purchasing power—i.e., the purchasing power per inhabitant—is one of the key characteristics for businesses deciding on site selection. Apart from that it also plays a major role in regional planning, pricing policy and market research. In this study we investigate the spatial correlations for relative purchasing power of the townships in Baden–Wurttemberg. In particular, changes in relative purchasing power are analysed for three different time intervals, 1987–1993, 1993–1998 and 1998–2004, by means of distance-dependent characteristics like the mark–correlation function, the Simpson indices α(r) and β(r) and by tests on random labelling. It is shown that there are positive correlations for small distances between different townships but that these positive correlations become weaker over the years until they are almost nonexistent (in the sense that hypotheses of random labelling are no longer rejected). A conclusion from this loss of spatial correlations with time is that the relative purchasing power might become more and more purely random. This means that the relative purchasing power in a township is less and less influenced by the relative purchasing power of townships nearby. We further analysed these changes in the Bodensee–Oberschwaben and Stuttgart regions to compare the development of the relative purchasing power in both urban and rural environments.

SUMMARY Spatial point patterns generated from bitmaps of images of processed reflection seismic profiles are analysed to quantify the reflectivity patterns. The point process characteristics for two different regions of a deep seismic reflection profile in northwestern Canada demonstrate that in both cases the points are not randomly distributed and that the point pattern distribution is different between the regions. The cluster effects for small point pair distances are stronger for the region of data where there is strong sedimentary layering than for the region where the layering is less distinct. As a result, it appears that future developments in point pattern analysis may provide a new tool for analysing spatial variations in reflection data.

Summary In this study, we quantitatively investigate the role of the M97 protein for viral morphogenesis in murine cytomegalovirus (MCMV)-infected fibroblast cells. For this purpose, a statistical analysis is performed for the spatial distribution of nuclear B-capsids (devoid of DNA, containing the scaffold) and C-capsids (filled with DNA). Cell nuclei infected with either wild-type or an M97 deletion mutant were compared. Univariate and multivariate point process characteristics (like Ripley's K-function, the L-function and the nearest neighbour distance distribution function) are investigated in order to describe and quantify the effects that the deletion of M97 causes to the process of DNA packaging into nucleocapsids. The estimation of the function L(r) −r reveals that with respect to the wild type there is an increased frequency of point pairs at a very short distance (less than approximately 100 nm) for both the B-capsids as well as for the C-capsids. For the M97 deletion mutant type this is no longer true. Here only the C-capsids show such a clustering behaviour, whereas for B-capsids it is almost nonexistant. Estimations of functionals such as the nearest neighbour distance distribution function confirmed these results. Thereby, a quantification is provided for the effect that the deletion of M97 leads to a loss of typical nucleocapsid clustering in MCMV-infected nuclei.

Microglia are classically considered to be immune cells in the brain, but have now been proven to be involved in neuronal activity as well. Here we stereologically analyzed the spatial arrangement of microglia in the mouse hippocampus. First, we estimated the numerical densities (NDs) of microglia identified by ionized calcium-binding adaptor molecule 1 (Iba1). Despite that microglia appeared to be evenly distributed throughout the hippocampal area, the NDs demonstrated significant dorsoventral, interregional, and interlaminar differences. Briefly, the NDs in the ventral hippocampus were significantly lower in the CA3 region than in the CA1 region and dentate gyrus, although no interregional differences were detectable in the dorsal hippocampus. Both in the CA1 and CA3 regions, the NDs were significantly higher in the stratum lacunosum-moleculare than in the remaining layers. Next, we investigated the spatial patterns of distribution of Iba1-labeled microglia and S100b-labeled astrocytes. So far as we examined, the somato–somatic contacts were not seen among microglia or among astrocytes, whereas the close apposition between microglia and astrocytes were occasionally detected. The 3D point process analysis showed that the spatial distribution of microglia was significantly repulsive. Because the statistical territory of single microglia was larger than that estimated from process tracing, they are not likely to touch each other with their processes. Astrocytes were distributed slightly repulsively with overlapping areas. The 3D point process analysis also revealed a significant spatial attraction between microglia and astrocytes. The present findings provide a novel anatomical basis for glial research. V C 2007 Wiley-Liss, Inc.

We consider random geometric models for telecommunication access networks and analyse their serving zones which can be given, for example, by a class of so-called Cox–Voronoi tessellations (CVTs). Such CVTs are constructed with respect to locations of network components, the nucleii of their induced cells, which are scattered randomly along lines induced by a Poisson line process. In particular, we consider two levels of network components and investigate these hierarchical models with respect to mean shortest path length and mean subscriber line length, respectively. We explain point-process techniques which allow for these characteristics to be computed without simulating the locations of lower-level components. We sustain our results by numerical examples which were obtained through Monte Carlo simulations, where we used simulation algorithms for typical Cox–Voronoi cells derived in a previous paper. Also, briefly, we discuss tests of correctness of the implemented algorithms. Finally, we present a short outlook to possible extensions concerning multi-level models and iterated random tessellations.

The role of specific structural patterns in keratin filament networks for regulating biophysical properties of epithelial cells is poorly understood. This is at least partially due to a lack of methods for the analysis of filament network morphology. We have previously developed a statistical approach to the analysis of keratin filament networks imaged by scanning electron microscopy. The segmentation of images in this study resulted in graph structures, i.e. tessellations, whose structural characteristics are now further investigated by iteratively fitting geometrical statistical models. An optimal model as well as corresponding optimal parameters are detected from a given set of possible random tessellation models, i.e. Poisson–Line tessellations (PLT), Poisson–Voronoi tessellations (PVT) and Poisson–Delaunay tessellations (PDT). Using this method, we investigated the remodeling of keratin filament networks in pancreatic cancer cells in response to transforming growth factor α (TGF α ), which is involved in pancreatic cancer progression. The results indicate that the fitting of random tessellation models represents a suitable method for the description of complex filament networks.

We explore real telecommunication data describing the spatial geometrical structure of an urban region and we propose a model fitting procedure, where a given choice of different non-iterated and iterated tessellation models is considered and fitted to real data. This model fitting procedure is based on a comparison of distances between characteristics of sample data sets and characteristics of different tessellation models by utilizing a chosen metric. Examples of such characteristics are the mean length of the edge-set or the mean number of vertices per unit area. In particular, after a short review of a stochastic-geometric telecommunication model and a detailed description of the model fitting algorithm, we verify the algorithm by using simulated test data and subsequently apply the procedure to infrastructure data of Paris.

A previous study by Schmid and Kazda (I. Schmid and M. Kazda. 2001. Can. J. For. Res. 31: 539–548) evaluated the vertical distribution and radial growth of coarse roots greater than 2 mm diameter in pure and mixed stands of Norway spruce (Picea abies (L.) Karst.) and European beech (Fagus sylvatica L.). The vertical distribution of roots of Norway spruce was fitted by an exponential function, while the root distribution of European beech was approximated by a gamma distribution. Now, in the present paper, planar point process models have been applied to investigate the spatial (two-dimensional) distribution of data for roots between 2 and 5 mm diameter. After a homogenization with respect to the vertical axis, the pair correlation function and the L function were estimated to fit Matérn-cluster point process models to the given root data. The models were finally vertically retransformed to provide information on the inhomogeneous spatial patterns of small roots as well as on the original shape and size of the root clusters. All models based on vertically transformed data confirmed that the root distribution patterns are not completely random, as they indicated root clustering for both species, with different degrees of exploitation intensity (clustering) between the two species. According to the Matérn-cluster models, Norway spruce had stronger clustering in smaller cluster regions, while roots of European beech formed weaker clusters in larger cluster regions. Furthermore, beech root clusters seemed to avoid overlapping. Together with previous studies on the root system of both species, the present study indicates more intensive belowground intraspecific competition for spruce than for beech. On the other hand, the clustering characteristics described indicate that European beech has a more sophisticated rooting system than Norway spruce. The spatial distribution of the inhomogeneous raw data is characterized by the clustering properties analysed in the present paper and by the vertical distribution previously studied.

We consider stationary Poisson line processes in the Euclidean plane and analyze properties of Voronoi tessellations induced by Poisson point processes on these lines. In particular, we describe and test an algorithm for the simulation of typical cells of this class of Cox–Voronoi tessellations. Using random testing, we validate our algorithm by comparing theoretical values of functionals of the zero cell to simulated values obtained by our algorithm. Finally, we analyze geometric properties of the typical Cox–Voronoi cell and compare them to properties of the typical cell of other well-known classes of tessellations, especially Poisson–Voronoi tessellations. Our results can be applied to stochastic–geometric modelling of networks in telecommunication and life sciences, for example. The lines can then represent roads in urban road systems, blood arteries or filament structures in biological tissues or cells, while the points can be locations of telecommunication equipment or vesicles, respectively.

The keratin filament network is an important part of the cytoskeleton. It is involved in the regulation of shape and viscoelasticity of epithelial cells. The morphology of keratin networks depends on post-translational modifications of keratin monomers. In-vitro studies indicated that network characteristics, such as filament crosslink density, determines the biophysical properties of the filament network. This report presents a quantitative method for the morphological analysis of keratin filament networks. Visualization of filaments was based on prefixation extraction of epithelial cells and scanning electron microscopy (SEM). SEM images were processed by a skeletonization algorithm to obtain a graph structure that represents individual filaments as well as their connections. This method was applied to investigate the effects of transforming growth factor alpha (TGFalpha) on the morphology of keratin networks in pancreatic cancer cells. TGFalpha contributes to pancreatic cancer progression and activates signalling pathways phosphorylating keratin monomers. Using this new method, a significant alteration to the keratin network morphology could be detected in response to TGFalpha.

Efficient syntheses of 5-brominated and 5,5'-dibrominated 2,2'-bipyridines and 2,2'-bipyrimidines, useful for the preparation of metal-complexing molecular rods, have been developed. 5-Bromo-2,2'-bipyridine, 5-bromo-5'-n-butyl-2,2'-bipyridine, and 5-bromo-5'-n-hexyl-2,2'-bipyridine were obtained by Stille coupling of 2,5-dibromopyridine with 2-trimethylstannylpyridine or the requisite 5-alkyl-2-trimethylstannylpyridine, obtained via regioselective zincation of a 3-alkylpyridine.BF(3) complex in the less hindered of the two reactive positions with lithium di-tert-butyl-(2,2,6,6-tetramethylpiperidino)zincate. 5,5'-Dibromo-2,2'-bipyridine was obtained by the reductive symmetric coupling of 2,5-dibromopyridine with hexa-n-butyldistannane. The yields of these coupling reactions ranged from 70 to 90%. 5-Bromo- and 5,5'-dibromo-2,2'-bipyrimidines were obtained in yields of 30 and 15%, respectively, by bromination of 2,2'-bipyrimidine, prepared from 2-chloropyrimidine in 80% yield by an improved reductive symmetric coupling procedure.

Mitogen-activated protein kinase (MAPK) family members such as c-jun N-terminal kinase (JNK) may act as signal transducers early during pancreatitis development and evidence indicates that MAPK phosphatases (MKP) downregulate MAPK. We therefore investigated expression and regulation of pancreatic MKP in vivo. Pancreatic MKP mRNA levels were near or below the detection threshold in unstimulated animals. Cerulein hyperstimulation strongly induced MKP-1, MKP-3, and MKP-5 expression, peaking 30 to 60 min after treatment. Thus, MKP's clearly are early responsive genes during pancreatitis induction. Interestingly, inhibition of MKP-1 expression by Ro-31-8220 maximally induced activation of JNK but not of p38 and ERK in acutely isolated acini. These effects indicate that JNK may indeed be a preferred MKP-1 substrate in vivo.

Among the surrogate endpoints for overall survival (OS) in oncological trials, progression-free survival (PFS) is used as an important endpoint especially in first or second line of cancer therapies. Basic formulae for the determination of sample sizes based on time to event data can be found in the literature. Assumptions about the distributions of the survival time for OS and PFS, the accrual time and the censoring time are of key importance. Most often only uniformly distributed patient accrual and no censoring are mentioned, whereas the event time is assumed to be exponentially distributed. Considering the dependence between PFS and OS, we will investigate how a three-state model that includes states of progression/response and death can be used for a joint modelling of progression-free survival and overall survival. Sample size/power calculations are discussed for the three-state model and compared to the estimations based on exponentially distributed OS times. These sample size calculations are based on the assumption of piecewise uniformly accrual and exponentially distributed censoring time. The new three-state model approach results in a 10–30 % lower sample size and a corresponding higher power. An application to a Phase III lung cancer trial illustrates how the new approach can be successfully applied to the planning of a trial and to the monitoring of the needed events for the PFS and OS analyses.

A synthetic approach to a two-dimensional grid polymer is proposed and the execution of initial steps is described. Pd-catalyzed coupling of (1,12-dicarba-closo-dodecaboran-1-yl)copper (10) with iodobenzene, m-diiodobenzene, and 1,3,5-triiodobenzene yielded the known 1,12-dicarba-closo-dodecaboran-1-ylbenzene (3) and the new m-bis(1,12-dicarba-closo-dodecaboran-1-yl)benzene (4) and 1,3,5-tris(1,12-dicarba-closo-dodecaboran-1-yl)benzene (1), respectively. Each arm of the trigonal connector 1 was provided with one or two sticky tentacles by conversion to 1,3,5-tris[12-((3-(ethylthio)propyl)dimethylsilyl)-1,12-dicarba-closo-dodecaboran-1-yl]benzene (7) and 1,3,5-tris[12-(bis(3-(ethylthio)propyl)methylsilyl)-1,12-dicarba-closo-dodecaboran-1-yl]benzene (8). Linear coupling of carboranyl CH terminals through a mercury atom produced very stable dimeric structures from 3 and 4. The carborane 3, its mercury-linked dimer 13, the 1:1 complex of 13 with 2,2‘-bipyridyl, and the 2:1 complex of 13 with 2,2‘-bipyrimidyl ...

Polo-like kinases (Plks) play an important role in cell cycle checkpoint controls and are over-expressed in acute myeloid leukaemia (AML). BI 2536, a novel Plk inhibitor, induces mitotic arrest and apoptosis. In this phase I/II trial of BI 2536 in 68 elderly patients with relapsed/refractory AML, three schedules were investigated (day 1, days 1-3, and days 1 + 8). Maximum tolerated dose was 350 and 200 mg in the day 1 and days 1 + 8 schedules, respectively. The day 1-3 schedule appeared equivalent to the day 1 schedule and was discontinued early. BI 2536 exhibited multi-compartmental pharmacokinetic behaviour. The majority of patients showed an increase of bone marrow cells in G2/M with a characteristic pattern of mitotic catastrophe. The overall response rate in the day 1 and day 1 + 8 schedules was 9% (5/54) with 2 complete and 3 partial responses. The majority of drug-related adverse events grade ≥3 were haematological. Taken together, Plk inhibition induced cell cycle arrest in AML blasts in vivo and BI 2536 monotherapy showed modest clinical activity in this poor prognosis patient group.

Small Rings, 90. – Peralkyl-Substituted Tetrahedranes Photolysis of the diazo compounds 4a, b generates adaman-tyltri-tert-butyltetrahedrane (9a) and tri-tert-butylisopropyltetrahedrane (9b), and the corresponding cyclobutadienes 10a, b. In contrast to tetrahedrane 9a, which results from an intramolecular addition in carbene 7a and also from photoisomerization of cyclobutadiene 10a, the only source for tetrahedrane 9b is the cheletropic cycloaddition of the carbenic center to the cyclopropene double bond in the photochemically produced carbene 7b. Tetrahedrane 9b is remarkable in its kinetic and thermal instability, which is caused by the reduced „corset effect” in this compound. An additional access to this tetrahedrane is possible via the diazomethanes 34A and 34B. The pyridazines 17b and 41, which are formed by thermolysis of the diazo compounds 4b, 34A and 34B lead to the azetes 19 and 43. Last but not least 17b and 41 are interesting molecules themselves because of their inherent chirality.

Afatinib (BIBW 2992) is an ErbB-family blocker that irreversibly inhibits signaling from all relevant ErbB-family dimers. Afatinib has demonstrated preclinical activity in human epidermal growth factor receptor HER2 (ErbB2)-positive and triple-negative xenograft models of breast cancer, and clinical activity in phase I studies. This was a multicenter phase II study enrolling patients with HER2-negative metastatic breast cancer progressing following no more than three lines of chemotherapy. No prior epidermal growth factor receptor-targeted therapy was allowed. Patients received 50-mg afatinib once daily until disease progression. Tumor assessment was performed at every other 28-day treatment course. The primary endpoint was clinical benefit (CB) for ≥4 treatment courses in triple-negative (Cohort A) metastatic breast cancer (TNBC) and objective responses measured by Response Evaluation Criteria in Solid Tumors in patients with HER2-negative, estrogen receptor-positive, and/or progesterone receptor-positive breast cancer (Cohort B). Fifty patients received treatment, including 29 patients in Cohort A and 21 patients in Cohort B. No objective responses were observed in either cohort. Median progression-free survival was 7.4 and 7.7 weeks in Cohorts A and B, respectively. Three patients with TNBC had stable disease for ≥4 treatment courses, one of them for 12 courses (median 26.3 weeks; range 18.9-47.9 weeks). The most frequently observed afatinib-associated adverse events (AEs) were gastrointestinal and skin-related side effects, which were manageable by symptomatic treatment and dose reductions. Afatinib pharmacokinetics were comparable to those observed in previously reported phase I trials. In conclusion, afatinib had limited activity in HER2-negative breast cancer. AEs were generally manageable and mainly affected the skin and the gastrointestinal tract., Clinical Trial, Phase II, Journal Article, Multicenter Study, Research Support, Non-U.S. Gov't, SCOPUS: ar.j, info:eu-repo/semantics/published

NMR and x-ray anal. indicated that pyridazine deriv. I exists in a twist conformation. A ring inversion barrier of 91.5 kJ/mol was found for I.

It is of central interest for tumour biology to explore the mechanisms of tumour cell proliferation. In this study, methods of spatial statistics were used to study the spatial distribution of proliferating cells within tumour tissue quantitatively and objectively. Mammary cancer tissue was studied as an example. It was attempted to clarify whether cell division occurs entirely at random (random labelling), i.e. the process of division occurs at random, independently from the state of the neighbouring nuclei, or whether the spatial distribution of proliferation is more complex, e.g. in the form of actively proliferating clusters alternating with relatively silent zones. In the case of random labelling, the reduced second moment functions K(r) of the labelled and the unlabelled nuclei would be identical. The same would hold for the pair correlation functions g(r). The alternative hypothesis is that the second-order properties of the processes of the labelled and the unlabelled nuclei are different. Twenty cases of invasive ductal mammary carcinomas were studied. The nuclei of proliferating cells were stained immunohistochemically with the monoclonal antibody MIB-1, which detects specifically the proliferation-associated nuclear antigen Ki 67. The planar coordinates of the tumor cell nucleus profiles from two rectangular visual fields per case were recorded. For each visual field, the following investigations were performed: estimation of the explorative summary characteristics K(r) and g(r), fitting of the parameters of a stationary Strauss hard-core model to the observed point patterns, estimation of two distance-dependent Simpson indices and Monte Carlo tests of all individual patterns on the null hypothesis of random labelling. Significant differences between the mean K-functions and the mean g-functions of the labelled and the unlabelled nuclei were found. Moreover, the mean interaction parameter gamma of the stationary Strauss hard-core model was significantly higher for the labelled nuclei than for the unlabelled nuclei. The estimates of the two distance-dependent Simpson indices showed a tendency of points with the same label towards a positive spatial correlation. In the Monte Carlo tests, the null hypothesis of random labelling was rejected for the majority of the visual fields. These four lines of investigation led to the concordant conclusion that the labelling of mammary carcinoma nuclei by MIB-1 is not simply random. The data suggest that the second-order properties of the point process of the labelled nuclei are significantly different from those of the unlabelled nuclei. In particular, the process of the labelled nuclei shows a higher degree of clustering (increased strength of interaction) than the process of the unlabelled points.

Background: BIBW 2992 (Tovok™*) is a novel, oral, irreversible inhibitor of the epidermal growth factor receptor (EGFR)/ human epidermal growth factor receptor (HER)1 and HER2 inhibitor. It has promising preclinical activity in HER2-negative MDA-MB-453 and triple-negative SUM 149-PT cell lines, and showed clinical Phase I activity. First results of a Phase II study of BIBW 2992 in patients with HER2-negative, hormone receptor (HR)-positive or triple-negative breast cancer who have progressed following no more than two prior lines of chemotherapy are presented. The trial was conducted as a multi-institutional, open-label study in Germany and Belgium.Methods: Eligible patients had stage IIIB or IV HER2-negative metastatic breast cancer (MBC), with progression following no more than two prior lines of chemotherapy. No prior EGFR-targeted therapy was allowed and measurable disease, Eastern Cooperative Oncology Group performance status of 0–2 and an adequate organ function were required. Patients received 50 mg BIBW 2992 once-daily until disease progression. Tumor assessment was performed every other treatment course (one course is 28 days). The primary endpoint was objective response rate by Response Evaluation Criteria In Solid Tumors criteria in patients with HR-positive and triple-negative MBC. The latter was changed to clinical benefit, i.e. objective response (OR) or stable disease (SD) on treatment for at least four cycles for patients with triple-negative disease. Safety data were collected and analyses are still ongoing.Results: A total of 56 patients were enrolled with 50 actually starting treatment on the trial, including 29 patients with triple-negative and 21 patients with HER2-negative and HR-positive MBC. No ORs were observed in either cohort. Three patients in the triple-negative cohort had SD for at least 4 treatment cycles, one of them for 12 cycles. The most frequently observed side-effects at snapshot date (on 49 patients) are diarrhea (Common Terminology Criteria for Adverse Events Grade 3 in 18 patients [36.7%]) and Grade 3 skin rash in two patients [4.1%]). These were managed by symptomatic treatments and dose reductions.Conclusion: Long-term oral administration of BIBW 2992 was safe in HER2-negative MBC patients. Side effects mainly affected the skin and gastrointestinal tract, and were manageable. Clinical benefit was achieved in a fraction of triple-negative MBC patients.*Trade name not FDA approved. Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 5062.

Diazocompound 1 turns out to be the ideal photochemical precursor for tetrahedrane 3. Upon thermolysis Dewarpyridazine 6 is fragmented quantitatively into tri- tert -butylazete 8 and pivalonitrile 9.

In a recent study, the capillarization of normal prostatic tissue and prostatic carcinoma tissue was characterized by means of explorative methods of spatial statistics. In the present paper, an attempt was made to go beyond the explorative approach and to characterize the observed point patterns of the capillary profiles on sections by means of a parametric model. For this purpose, the flexible class of Gibbs processes was considered. Specifically, stationary Strauss hard-core processes were fitted to the observed point patterns. The goodness of fit achieved by the model was checked by simulations with the Markov chain Monte Carlo method using the Metropolis-Hastings algorithm. Model fitting and simulations were performed with the help of the spatstat package under R. The observed point patterns were in some cases compatible with realizations of stationary Strauss hard-core processes for all ranges of spatial interaction. However, deviations from the model were found for one or more domains of ranges in other cases. In the tumour tissue, a highly significant decrease of the interaction parameter of the Strauss hard-core process could be found as compared to the normal prostatic tissue. This finding is discussed in terms of a loss of the normal lobular architecture of the glands in the tumour tissue.

Cell migration is an essential element in the immune response on the one hand and in cancer metastasis on the other hand. The architecture of the actin network in lamellipodia determines the elasticity of the leading edge and contributes to the regulation of migration. We have implemented a new method for the analysis of actin network morphology in the lamellipodia of B16F1 mouse melanoma cells. This method is based on fitting multi-layer geometrical models to electron microscopy images of lamellipodial actin networks. The chosen model and F-actin concentrations are thereby deterministic parameters. Using this approach, we identified distinct structural features of actin networks in lamellipodia. The mesh size which defines the elasticity of the lamellipodium was determined as 34 and 78?nm for a two-layer network at a total actin concentration of 9.6?mg?ml?1. These data lead to estimates of the low frequency elastic shear moduli which differ by more than a magnitude between the two layers. These findings indicate an anisotropic shear modulus of the lamellipodium with the stiffer layer being the dominant structure against deformations in the lamellipodial plane and the softer layer contributing significantly at lower indentations perpendicular to the lamellipodial plane. This combination creates a material that is optimal for pushing forward as well as squeezing through narrow spaces.

Blood capillaries are thread-like structures that may be considered as an example of a spatial fibre process in three dimensions. At light microscopy, the capillary profiles appear as a planar point process on sections. It has recently been shown that the observed pair correlation function g(r) of the centres of the fibre profiles on two-dimensional sections may be used to estimate the reduced pair correlation function of stationary and isotropic fibre processes in three dimensions. In the present study, we explored how this approach may be extended to statistical analysis of reduced g-functions of capillaries from multiple specimens of different groups and with replicated observations. The methods were applied to normal prostatic tissue compared with prostate cancer. Confidence intervals for the mean reduced g-functions of groups were estimated for fixed r-values parametrically using the t-distribution, and by bootstrap methods. Each estimated reduced g-function was furthermore characterized in terms of its first maximum and minimum. The mean length of capillaries per unit tissue volume was significantly higher in prostate cancer tissue than in normal prostate tissue. Significant differences between the mean reduced g-functions of malignant and benign lesions could be demonstrated for two domains of r-values. In general, bootstrap-based confidence intervals were slightly wider than parametrically estimated confidence intervals. Falsely negative lower bounds of the intervals, which sometimes arose using the parametric approach, could be avoided by the bootstrap method. Testing of group mean values for significant differences by the bootstrap method yielded more conservative results than multiple t-tests. The functional value of the first maximum of the reduced g-function and a global statistical parameter of short-range ordering was significantly reduced in the carcinoma group. Prostate cancer tissue is more densely supplied with capillaries than normal prostate tissue and the three-dimensional arrangement of the vessels differs with respect to interaction at various distance ranges. In the local approach used here, bootstrap methods can be used as a robust statistical tool for the computation of confidence intervals and group comparisons of mean reduced g-functions at specific ranges of interaction.

Point process characteristics like for example Ripley’s K-function, the L-function or Baddeley’s J-function are especially useful for cases of data with significant differences with respect to intensities. We will discuss two examples in the fields of cell biology and ecology were these methods can be applied. They have been chosen, because they demonstrate the wide range of applications for the described techniques and because both examples have specific interest- ing properties. While the point patterns regarded in the first application are three dimensional, the second application reveals planar point patterns having a vertically inhomogeneous structure.

We suggest the use of bootstrap methods for inference from stereological estimates of volume fraction. An informal introduction to stereological estimation of volume fraction and to principles of bootstrap techniques is given. The bootstrap method is a robust computer-intensive resampling technique, based on independent random sampling from a data set with replacement. Bootstrap methods were used to estimate confidence intervals for volume fractions, and to test for a significant difference between estimated volume fractions from two samples. Two sampling designs are considered: independent replicated samples (visual fields) from a single object, and estimates of volume fraction from multiple independent objects. The methods are presented as worked examples on real data sets obtained from tumour pathology (mammary cancer, pancreatic cancer). The volume fraction of glandular lumina per total volume of the epithelial phase was chosen as target parameter. It indicates the degree of glandular differentiation in adenocarcinomas and is estimated as a ratio-of-means statistic with variable denominator within cases. The confidence intervals of the volume fraction estimated by the bootstrap method were slightly narrower than the parametrically calculated confidence intervals for all data sets. The outcomes of significance tests based on the bootstrap technique were unchanged as compared with classical tests based on the assumptions of normality and homoscedasticity of the data. Special attention was paid to the reproducibility of the bootstrap technique in replicated trials on the same data.

Translocation of genes into the pericentromeric heterochromatin occurs during cellular differentiation and leads to a long-term silencing of these genes. Consequently, a structural remodelling of this heterochromatin compartment is observed during differentiation but this remains to be defined from a topological point of view. In a previous study, we analysed the three-dimensional (3D) distribution patterns of centromere clusters (chromocentres) by confocal scanning laser microscopy and found that differentiation of the promyelocytic leukaemia cell line NB4 along the neutrophil lineage is associated with a progressive clustering of centromeres. This clustering was reflected by a decreased number of detectable chromocentres, i.e. groups of centromeres with a distance below the diffraction-limited resolution of optical microscopy. The purpose of this study was to perform a statistical analysis of the 3D distribution of chromocentres in NB4 cells. Several point field characteristics (Ripley's K-function, L-function, pair correlation function, nearest-neighbour distribution function) were investigated to describe the topology of chromocentres during differentiation of NB4 cells. The pair correlation function revealed a higher frequency of chromocentre distances between 350 nm and 800 nm in undifferentiated NB4 cells as compared with differentiated cells. The L-function and the nearest-neighbour distribution function confirmed these results. These data imply the existence of intranuclear heterochromatin zones formed by functionally related centromeric regions. In view of the observed decrease in the number of detectable chromocentres during differentiation, we hypothesize that these zones with a diameter of 350-800 nm in undifferentiated NB4 cells contract into zones with a diameter below 350 nm in differentiated cells.

Im Transformationsprozess der Wirtschaft in Ostdeutschland wurde die Industrieforschung besonders stark abgeschmolzen. Zudem erschwerten Phänomene der Marktunvollkommenheit im Bereich der wirtschaftsnahen Forschung und Entwicklung (FuE) und Innovation (Informationsdefizite und Unsicherheit, externe Effekte, Unteilbarkeiten) die Neuformierung des regionalen Innovationssystems. Der Bund und die neuen Länder haben deshalb zahlreiche Maßnahmen zur finanziellen Unterstützung des Neuaufbaus einer leistungsfähigen Industrieforschung ergriffen. Dabei ist generell umstritten, in welchem Umfang und mit welchen Instrumenten der Staat in die marktnahen FuE-Aktivitäten der privaten Wirtschaft eingreifen sollte. In diesem Beitrag wird ein Überblick über die Maßnahmen der staatlichen Förderung der industriellen FuE in Ostdeutschland im letzten Jahrzehnt gegeben. Ein Schwerpunkt ist die Darstellung der staatlichen Zuschüsse zu den FuE-Aufwendungen als Hauptform der Förderung. In der anschließenden Wirkungsanalyse dieser Förderung stehen zwei Fragen im Mittelpunkt: Wie hat sie auf die Entwicklung des FuE-Potentials der Industrie gewirkt? Welchen Beitrag leistet das FuE-Potential in den Unternehmen und den wirtschaftsnahen Forschungseinrichtungen der neuen Länder zur technologischen Leistungsfähigkeit der ostdeutschen Wirtschaft?