Minireview: The androgen receptor in breast tissues: growth inhibitor, tumor suppressor, oncogene?

Androgen receptor (AR) signaling exerts an antiestrogenic, growth-inhibitory influence in normal breast tissue, and this role may be sustained in estrogen receptor α (ERα)-positive luminal breast cancers. Conversely, AR signaling may promote growth of a subset of ERα-negative, AR-positive breast cancers with a molecular apocrine phenotype. Understanding the molecular mechanisms whereby androgens can elicit distinct gene expression programs and opposing proliferative responses in these two breast cancer phenotypes is critical to the development of new therapeutic strategies to target the AR in breast cancer.

An experimental methodology to relate local strain to microstructural texture

This paper introduces an experimental methodology for obtaining high resolution full-field strain measurements in polycrystalline metals. The (sub)grain level resolution of these measurements was indispensable for relating measured strain fields to observed microstructure in the material. Microstructural information was obtained through electron backscatter diffraction and the optical technique of digital image correlation (DIC) was used to acquire full-field deformation measurements. By spatially overlaying both sets of results, the effects of different microstructural features such as orientation, grain boundary character, misorientation between grains, and twin boundaries on material response can be quantitatively studied. To obtain the necessary resolution for such measurements, the images used in DIC had to be captured at high magnifications. This necessity reduces the field of view and constrains the area of interest that can be monitored. To address this issue, results from adjacent measurement areas are combined together to create a data set with high spatial strain resolution over a larger region than can otherwise be observed. The procedure for performing this technique is outlined here, along with benefits, drawbacks, possible modifications, and example applications of the technique to cyclic plasticity and fatigue crack growth.

Sedimentary radioactive tracers and diffusive models

This paper examines the underlying assumptions and consequences of applying a steady-state equation to sediment profiles of radioactive tracers in order to deconvolute sedimentation from bioturbation processes modelled as a diffusive type process. Several factors follow immediately from this investigation: (i) if the observed radioactive concentration increases with depth over any finite depth range then the proposed steady-state, constant flux equation is not applicable. Any increase in radioactive concentration with depth implies a negative mixing coefficient which is a physical impossibility; (ii) when the radioactive concentration systematically decreases with increasing sedimentary depth then solutions to the steady-state conservation equation exist only when either the constant solid state flux to the sediment surface is small enough so that a positive mixing coefficient results or when the mixing coefficient is small enough so that a positive flux results. If the radioactive concentration, porosity and/or density of the solid phase are such that the proposed equation is inappropriate (because no physically acceptable solution exists) then one must abandon the proposed steady-state equation. Further: if the flux of solid sediment to the sediment surface varies with time then, of course, a steady-state conservation equation is also inappropriate. Simple examples illustrate that the assumption of steady-state restricts the applicability of this modelling approach to a relatively small sub-set of expected situations in the real world.

A COMPARATIVE STUDY OF THE BIOLOGICAL CHARACTERS AND PATHOGENESIS OF BACILLUS X (STERNBERG), BACILLUS ICTEROIDES (SANARELLI), AND THE HOG-CHOLERA BACILLUS (SALMON AND SMITH)

1. Bacillus X (Sternberg) belongs to the colon group. 2. Bacillus icteroides (Sanarelli) is a member of the hog-cholera group. 3. The various channels of infection, the duration of the disease and the gross and microscopical lesions in mice, guinea-pigs and rabbits are the same for Bacillus icteroides and the hog-cholera bacillus. 4. The clinical symptoms and the lesions observed in dogs inoculated intravenously with Bacillus icteroides, are reproduced in these animals by infection with the hog-cholera bacillus. 5. Bacillus icteroides when fed to the domestic pig causes fatal infection, accompanied by diphtheritic, necrotic and ulcerative lesions in the digestive tract, such as are seen in hogs when infected with the hog-cholera bacillus. 6. This disease may be acquired by exposing swine in pens already infected with Bacillus icteroides, or by feeding them with the viscera of infected pigs. 7. Guinea-pigs may be immunized with sterilized cultures ofBacillus icteroides from a fatal dose of the hog-cholera bacillus and vice versa. 8. Rabbits may be rendered immune by gradually increasing doses of a living culture of Bacillus icteroides of weak virulence from a fatal dose of a virulent culture of the hog-cholera bacillus 9. The sera of animals immunized with Bacillus icteroides and with the hog-cholera bacillus, respectively, show a marked reciprocal agglutinative reaction. 10. While the blood of yellow fever practically does not exercise an agglutinative reaction upon Bacillus icteroides, the blood of hog-cholera agglutinates this bacillus in a much more marked degree, thus pointing, we think, to the closer etiological relationship of this bacillus to hog-cholera than to yellow fever.

Mitochondrial function and redox state in mammalian embryos

Mitochondria play a central and multifaceted role in the mammalian egg and early embryo, contributing to many different aspects of early development. While the contribution of mitochondria to energy production is fundamental, other roles for mitochondria are starting to emerge. Mitochondria are central to intracellular redox metabolism as they produce reactive oxygen species (ROS, the mediators of oxidative stress) and they can generate TCA cycle intermediates and reducing equivalents that are used in antioxidant defence. A high cytosolic lactate dehydrogenase activity coupled with dynamic levels of cytosolic pyruvate is responsible for a very dynamic intracellular redox state in the oocyte and embryo. Mammalian embryos have a low glucose metabolism during the earliest stages of development, as both glycolysis and the pentose phosphate pathway are suppressed. The mitochondrial TCA cycle is therefore the major source of reducing equivalents in the cytosol so that any change in mitochondrial function in the embryo will be reflected in changes in the intracellular redox state. In the mouse, the metabolic substrates used by the oocyte and early embryo each have a different impact on the intracellular redox state. Pyruvate which oxidises the cytosolic redox state, acts as an energetic and redox substrate whereas lactate, which reduces the cytosolic redox state, acts only as a redox substrate. Mammalian early embryos are very sensitive to oxidative stress which can cause permanent developmental arrest before zygotic genome activation and apoptosis in the blastocyst. The oocyte stockpiles antioxidant defence for the early embryo to cope with exogenous and endogenous oxidant insults arising during early development. Mitochondria provide ATP for glutathione (GSH) production during oocyte maturation and also participate in the regeneration of NADPH and GSH during early development. Finally, a number of pathological conditions or environmental insults impair early development by altering mitochondrial function, illustrating the centrality of mitochondrial function in embryo development.

Reconstructing foveal pit morphology from optical coherence tomography imaging

AIM

The aim of this study was to describe an automated method for extracting quantitative measures of foveal morphology from optical coherence tomography (OCT) images of the human retina.

METHODS

We performed a methodological study and retrospective investigation of selected cases. Sixty-five human subjects were included: 61 healthy subjects and four female carriers of blue-cone monochromacy (BCM). Thickness data from B-scans traversing the foveal pit were fitted to a mathematical model designed to capture the contour of the foveal surface. From this model, various metrics of foveal morphology were extracted (pit depth, diameter and slope).

RESULTS

Mathematical descriptions of foveal morphology enabled quantitative and objective evaluation of foveal dimensions from archived OCT data sets. We found a large variation in all aspects of the foveal pit (depth, diameter and slope). In myopes and BCM carriers, foveal pits were slightly less deep and had a more shallow slope, although these differences were not significant.

CONCLUSIONS

Offline analysis of OCT data sets enables quantitative assessment of foveal morphology. The algorithm works on the Stratus and Cirrus macular thickness protocols, as well as the Spectralis and Bioptigen radial-line scan protocols, and can be objectively applied to existing data sets. These metrics will be useful in following changes associated with diseases such as retinopathy of prematurity and high myopia, as well as in studying normal postnatal development of the human fovea.

Patients’ experiences with navigation for cancer care

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Background: Patient navigation is a promising strategy for improving cancer care. We examined (1) how navigation influences patients’ perspectives on their cancer care and (2) the most effective (i.e., meaningful or valuable) aspects of navigation from the patient's viewpoint. Methods: We conducted post-study patient interviews from a randomized controlled trial (usual care vs. patient navigation services) from cancer diagnosis through treatment completion. Patients were recruited from 11 primary care, hospital and community oncology practices in Monroe County, NY. We interviewed patients about their specific experiences with cancer care including their expectations and experience of patient navigation or, for non-navigated patients, other sources of assistance. Results: Thirty-five patients (32 female, 3 male) newly diagnosed with breast (n = 28) or colorectal (n = 7) cancer who completed the study and were interviewed from May 2007 through March 2008. Patients who received navigation were very positive about their experience. Valued aspects of navigation included emotional support, assistance with information needs and problem-solving (such as with insurance or financial stressors), and logistical coordination of cancer care. Unmet cancer care needs expressed by patients randomized to usual care consisted of lack of assistance or support with childcare, household responsibilities, coordination of care, and emotional support. Conclusions: Cancer patients value navigation. Instrumental benefits were the most important expectations for navigation from navigated and non-navigated patients. However, when describing their actual experience of navigation, navigated patients frequently mentioned receiving emotional support as well as assistance with information needs, problem-solving, and logistical aspects of cancer care coordination.

No significant financial relationships to disclose.