Automatic quantification of microvessels using unsupervised image analysis.

An automatic method for quantification of images of microvessels by computing area proportions and number of objects is presented. The objects are segmented from the background using dynamic thresholding of the average component size histogram. To be able to count the objects, fragmented objects are connected, all objects are filled, and touching objects are separated using a watershed segmentation algorithm. The method is fully automatic and robust with respect to illumination and focus settings. A test set consisting of images grabbed with different focus and illumination for each field of view, was used to test the method, and the proposed method showed less variation than the intraoperator variation using manual threshold. Further, the method showed good correlation to manual object counting (r = 0.80) on an other test set.     

Cancer as a dynamical phase transition

Background

We review and extend the work of Rosen and Casti who discuss category theory with regards to systems biology and manufacturing systems, respectively.

Results

We describe anticipatory systems, or long-range feed-forward chemical reaction chains, and compare them to open-loop manufacturing processes. We then close the loop by discussing metabolism-repair systems and describe the rationality of the self-referential equation f = f (f). This relationship is derived from some boundary conditions that, in molecular systems biology, can be stated as the cardinality of the following molecular sets must be about equal: metabolome, genome, proteome. We show that this conjecture is not likely correct so the problem of self-referential mappings for describing the boundary between living and nonliving systems remains an open question. We calculate a lower and upper bound for the number of edges in the molecular interaction network (the interactome) for two cellular organisms and for two manufacturomes for CMOS integrated circuit manufacturing.

Conclusions

We show that the relevant mapping relations may not be Abelian, and that these problems cannot yet be resolved because the interactomes and manufacturomes are incomplete.     

Small-animal PET imaging of amyloid-beta plaques with [11C]PiB and its multi-modal validation in an APP/PS1 mouse model of Alzheimer's disease

In vivo imaging and quantification of amyloid-β plaque (Aβ) burden in small-animal models of Alzheimer's disease (AD) is a valuable tool for translational research such as developing specific imaging markers and monitoring new therapy approaches. Methodological constraints such as image resolution of positron emission tomography (PET) and lack of suitable AD models have limited the feasibility of PET in mice. In this study, we evaluated a feasible protocol for PET imaging of Aβ in mouse brain with [(11)C]PiB and specific activities commonly used in human studies. In vivo mouse brain MRI for anatomical reference was acquired with a clinical 1.5 T system. A recently characterized APP/PS1 mouse was employed to measure Aβ at different disease stages in homozygous and hemizygous animals. We performed multi-modal cross-validations for the PET results with ex vivo and in vitro methodologies, including regional brain biodistribution, multi-label digital autoradiography, protein quantification with ELISA, fluorescence microscopy, semi-automated histological quantification and radioligand binding assays. Specific [(11)C]PiB uptake in individual brain regions with Aβ deposition was demonstrated and validated in all animals of the study cohort including homozygous AD animals as young as nine months. Corresponding to the extent of Aβ pathology, old homozygous AD animals (21 months) showed the highest uptake followed by old hemizygous (23 months) and young homozygous mice (9 months). In all AD age groups the cerebellum was shown to be suitable as an intracerebral reference region. PET results were cross-validated and consistent with all applied ex vivo and in vitro methodologies. The results confirm that the experimental setup for non-invasive [(11)C]PiB imaging of Aβ in the APP/PS1 mice provides a feasible, reproducible and robust protocol for small-animal Aβ imaging. It allows longitudinal imaging studies with follow-up periods of approximately one and a half years and provides a foundation for translational Alzheimer neuroimaging in transgenic mice.     

The variable roads to sacrifice: Isotopic investigations of human remains from Chotuna‐Huaca de los Sacrificios,Lambayeque, Peru

This study investigates two key variables—residential context and subsistence—among sacrificial victims dating to the Late Horizon (A.D. 1450–1532) in the Huaca de los Sacrificios at the Chotuna‐Chornancap Archaeological Complex in north coastal Peru. We investigate whether aspects of sacrifice in this distant coastal province mirrored that found in Inca heartland contexts such as the capacocha, or remained more typical of coastal sacrificial traditions. Stable carbon, nitrogen, and oxygen isotope values were characterized in bone carbonate, bone collagen, and hair keratin to estimate geographic residence during the decade before death and diet in the decade, versus months, before death. Bone δ¹⁸O_carbonate values have a mean (±SD) of 26.8 ± 1.1%, bone δ¹³C_carbonate values ?6.7 ± 1.7%, and bone δ¹³C_collagen values 11.8 ± 1.3%; bone δ¹⁵N_collagen values have a mean of 11.5 ± 1.3%. Combined hair δ¹³C_keratin values have a mean of ?12.8 ± 1.6%, and hair δ¹⁵N_keratin values 10.8 ± 1.3%. In contrast to contemporaneous coastal and highland contexts, we are unable to identify immigrants among the sacrificed individuals or changes in diet that indicate provisioning with a standardized diet leading up to death. Instead, results suggest that victims were local to the area, but consumed moderately variable diets consistent with local subsistence patterns. These findings suggest a distinct pattern of human sacrifice in the Late Horizon and underscore the regional and temporal variation in sacrificial practices in the central Andes. Am J Phys Anthropol 151:22–37, 2013. © 2013 Wiley Periodicals, Inc.     

Cell division in the cerebral cortex of adult rats after photothrombotic ring stroke

Neurogenesis has been shown to occur in the cerebral cortex in adult rats after ischemic stroke. The origin of the newborn neurons is largely unknown. This study aimed to explore cell division in the poststroke penumbral cortex. Adult male Wistar rats were subjected to photothrombotic ring stroke. After repeated delivery of the DNA duplication marker BrdU, the animals were sacrificed at various times poststroke. BrdU was detected by immunohistochemistry/immunofluorescence labeling, as was the M-phase marker Phos H3 and the spindle components α-tubulin/γ-tubulin. DNA damage was examined by TUNEL staining. Cell type was ascertained by double immunolabeling with the neuronal markers Map-2ab/β-tubulin III and NeuN/Hu or the astrocyte marker GFAP. From 16h poststroke, BrdU-immunolabeled cells appeared in the penumbral cortex. From 24h, Phos H3 was colocalized with BrdU in the nuclei. Mitotic spindles immunolabeled by α-tubulin/γ-tubulin appeared inside the cortical cells containing BrdU-immunopositive nuclei. Unexpectedly, the markers of neuronal differentiation, Map-2ab/β-tubulin III/NeuN/Hu, were expressed in the Phos H3-immunolabeled cells, and NeuN was detected in some cells containing spindles. This study suggests that in response to a sublethal ischemic insult, endogenous cells with neuronal immunolabeling may duplicate their nuclear DNA and commit cell mitosis to generate daughter neurons in the penumbral cortex in adult rats.     

Viscoelastic behaviour of human mesenchymal stem cells

Background  

In this study, we have investigated the viscoelastic behaviour of individual human adult bone marrow-derived mesenchymal stem cells (hMSCs) and the role of F-actin filaments in maintaining these properties, using micropipette aspiration technique together with a standard linear viscoelastic solid model.