Nonlinear studies of tumor morphological stability using a two-fluid flow model.

We consider the nonlinear dynamics of an avascular tumor at the tissue scale using a two-fluid flow Stokes model, where the viscosity of the tumor and host microenvironment may be different. The viscosities reflect the combined properties of cell and extracellular matrix mixtures. We perform a linear morphological stability analysis of the tumors, and we investigate the role of nonlinearity using boundary-integral simulations in two dimensions.

An undergraduate laboratory exercise examining the psychomotor stimulant effects of caffeine in laboratory rats.

This paper describes an exercise in a Systems and Behavioral Neuroscience with Laboratory class, an introductory laboratory class taken by Barnard College students majoring in a wide range of academic topics. The study took place over three weeks, allowing students to assess the effects of caffeine on motor stimulation in laboratory rats. The within-subject design involved injecting rats with three different caffeine doses and measuring five different motor outputs in a standard open field.

Density-dependent quiescence in glioma invasion: instability in a simple reaction-diffusion model for the migration/proliferation dichotomy.

Gliomas are very aggressive brain tumours, in which tumour cells gain the ability to penetrate the surrounding normal tissue. The invasion mechanisms of this type of tumour remain to be elucidated. Our work is motivated by the migration/proliferation dichotomy (go-or-grow) hypothesis, i.

Predictions of tumour morphological stability and evaluation against experimental observations.

The hallmark of malignant tumours is their spread into neighbouring tissue and metastasis to distant organs, which can lead to life threatening consequences. One of the defining characteristics of aggressive tumours is an unstable morphology, including the formation of invasive fingers and protrusions observed both in vitro and in vivo. In spite of extensive biological, clinical and modelling study and research at physical scales ranging from the molecular to the tissue, the driving dynamics of tumour invasiveness are not completely understood, partly because it is challenging to observe and study cancer as a multi-scale system.

Early involvement of synapsin III in neural progenitor cell development in the adult hippocampus.

Synapsin III is a synaptic vesicle-associated protein that is expressed in cells of the subgranular layer of the hippocampal dentate gyrus, a brain region known to sustain substantial levels of neurogenesis into adulthood. Here we tested the hypothesis that synapsin III plays a role in adult neurogenesis with synapsin III knockout and wild-type mice. Immunocytochemistry of the adult hippocampal dentate gyrus revealed that synapsin III colocalizes with markers of neural progenitor cell development (nestin, PSA-NCAM, NeuN, and Tuj1) but did not colocalize with markers of mitosis (Ki67 and PCNA).

Bmi-1-green fluorescent protein-knock-in mice reveal the dynamic regulation of bmi-1 expression in normal and leukemic hematopoietic cells.

The ability to self-renew is essential for all kinds of stem cells regardless of tissue type. One of the best candidate genes involved in conferring self-renewal capacity is Bmi-1, which has been proven to be essential for the maintenance of both normal adult hematopoietic and leukemia stem cells, as well as adult neural stem cells. To investigate the possible role of Bmi-1 in other cell types that also self-renew, we generated Bmi-1-green fluorescent protein (GFP)-knock-in mice, in which GFP was expressed under the endogenous transcriptional regulatory elements of the Bmi-1 gene.

Repeated restraint stress suppresses neurogenesis and induces biphasic PSA-NCAM expression in the adult rat dentate gyrus.

Chronic restraint stress has been shown to induce structural remodelling throughout the interconnected dentate gyrus-CA3 fields. To find out how this stressor affects the rate of adult hippocampal neurogenesis, we subjected rats to acute or chronic restraint stress and assessed the proliferation, survival and differentiation of newly born cells in the dentate gyrus. We also examined polysialylated neural cell adhesion molecule expression, a molecule normally expressed in immature neurons and important for morphological plasticity.