Quantitative role of the human papillomavirus type 16 E5 gene during the productive stage of the viral life cycle

Human papillomaviruses (HPVs) are small circular DNA viruses that cause warts. Infection with high-risk anogenital HPVs, such as HPV type 16 (HPV16), is associated with human cancers, specifically cervical cancer. The life cycle of HPVs is intimately tied to the differentiation status of the host epithelium and has two distinct stages: the nonproductive stage and the productive stage. In the nonproductive stage, which arises in the poorly differentiated basal epithelial compartment of a wart, the virus maintains itself as a low-copy-number nuclear plasmid. In the productive stage, which arises as the host cell undergoes terminal differentiation, viral DNA is amplified; the capsid genes, L1 and L2, are expressed; and progeny virions are produced. This stage of the viral life cycle relies on the ability of the virus to reprogram the differentiated cells to support DNA synthesis. Papillomaviruses encode multiple oncoproteins, E5, E6, and E7. In the present study, we analyze the role of one of these viral oncogenes, E5, in the viral life cycle. To assess the role of E5 in the HPV16 life cycle, we introduced wild-type (WT) or E5 mutant HPV16 genomes into NIKS, a keratinocyte cell line that supports the papillomavirus life cycle. By culturing these cells under conditions that allow them to remain undifferentiated, a state similar to that of basal epithelial cells, we determined that E5 does not play an essential role in the nonproductive stage of the HPV16 life cycle. To determine if E5 plays a role in the productive stage of the viral life cycle, we cultured keratinocyte populations in organotypic raft cultures, which promote the differentiation and stratification of epithelial cells. We found that cells harboring E5 mutant genomes displayed a quantitative reduction in the percentage of suprabasal cells undergoing DNA synthesis, compared to cells containing WT HPV16 DNA. This reduction in DNA synthesis, however, did not prevent amplification of viral DNA in the differentiated cellular compartment. Likewise, late viral gene expression and the perturbation of normal keratinocyte differentiation were retained in cells harboring E5 mutant genomes. These data demonstrate that E5 plays a subtle role during the productive stage of the HPV16 life cycle.     

A Spore Counting Method and Cell Culture Model for Chlorine Disinfection Studies of Encephalitozoon syn. Septata intestinalis

The microsporidia have recently been recognized as a group of pathogens that have potential for waterborne transmission; however, little is known about the effects of routine disinfection on microsporidian spore viability. In this study, in vitro growth of Encephalitozoon syn. Septata intestinalis, a microsporidium found in the human gut, was used as a model to assess the effect of chlorine on the infectivity and viability of microsporidian spores. Spore inoculum concentrations were determined by using spectrophotometric measurements (percent transmittance at 625 nm) and by traditional hemacytometer counting. To determine quantitative dose-response data for spore infectivity, we optimized a rabbit kidney cell culture system in 24-well plates, which facilitated calculation of a 50% tissue culture infective dose (TCID₅₀) and a minimal infective dose (MID) for E. intestinalis. The TCID₅₀ is a quantitative measure of infectivity and growth and is the number of organisms that must be present to infect 50% of the cell culture wells tested. The MID is as a measure of a system's permissiveness to infection and a measure of spore infectivity. A standardized MID and a standardized TCID₅₀ have not been reported previously for any microsporidian species. Both types of doses are reported in this paper, and the values were used to evaluate the effects of chlorine disinfection on the in vitro growth of microsporidia. Spores were treated with chlorine at concentrations of 0, 1, 2, 5, and 10 mg/liter. The exposure times ranged from 0 to 80 min at 25°C and pH 7. MID data for E. intestinalis were compared before and after chlorine disinfection. A 3-log reduction (99.9% inhibition) in the E. intestinalis MID was observed at a chlorine concentration of 2 mg/liter after a minimum exposure time of 16 min. The log₁₀ reduction results based on percent transmittance-derived spore counts were equivalent to the results based on hemacytometer-derived spore counts. Our data suggest that chlorine treatment may be an effective water treatment for E. intestinalis and that spectrophotometric methods may be substituted for labor-intensive hemacytometer methods when spores are counted in laboratory-based chlorine disinfection studies.     

Anti-Transforming Growth Factor ? Antibody Treatment Rescues Bone Loss and Prevents Breast Cancer Metastasis to Bone

Breast cancer often metastasizes to bone causing osteolytic bone resorption which releases active TGFβ. Because TGFβ favors progression of breast cancer metastasis to bone, we hypothesized that treatment using anti-TGFβ antibody may reduce tumor burden and rescue tumor-associated bone loss in metastatic breast cancer. In this study we have tested the efficacy of an anti-TGFβ antibody 1D11 preventing breast cancer bone metastasis. We have used two preclinical breast cancer bone metastasis models, in which either human breast cancer cells or murine mammary tumor cells were injected in host mice via left cardiac ventricle. Using several in vivo, in vitro and ex vivo assays, we have demonstrated that anti-TGFβ antibody treatment have significantly reduced tumor burden in the bone along with a statistically significant threefold reduction in osteolytic lesion number and tenfold reduction in osteolytic lesion area. A decrease in osteoclast numbers (p = 0.027) in vivo and osteoclastogenesis ex vivo were also observed. Most importantly, in tumor-bearing mice, anti-TGFβ treatment resulted in a twofold increase in bone volume (p<0.01). In addition, treatment with anti-TGFβ antibody increased the mineral-to-collagen ratio in vivo, a reflection of improved tissue level properties. Moreover, anti-TGFβ antibody directly increased mineralized matrix formation in calverial osteoblast (p = 0.005), suggesting a direct beneficial role of anti-TGFβ antibody treatment on osteoblasts. Data presented here demonstrate that anti-TGFβ treatment may offer a novel therapeutic option for tumor-induced bone disease and has the dual potential for simultaneously decreasing tumor burden and rescue bone loss in breast cancer to bone metastases. This approach of intervention has the potential to reduce skeletal related events (SREs) in breast cancer survivors.     

Natural images from the birthplace of the human eye

Here we introduce a database of calibrated natural images publicly available through an easy-to-use web interface. Using a Nikon D70 digital SLR camera, we acquired about six-megapixel images of Okavango Delta of Botswana, a tropical savanna habitat similar to where the human eye is thought to have evolved. Some sequences of images were captured unsystematically while following a baboon troop, while others were designed to vary a single parameter such as aperture, object distance, time of day or position on the horizon. Images are available in the raw RGB format and in grayscale. Images are also available in units relevant to the physiology of human cone photoreceptors, where pixel values represent the expected number of photoisomerizations per second for cones sensitive to long (L), medium (M) and short (S) wavelengths. This database is distributed under a Creative Commons Attribution-Noncommercial Unported license to facilitate research in computer vision, psychophysics of perception, and visual neuroscience.     

The effect of body mass index on global brain volume in middle-aged adults: a cross sectional study

Background  

Obesity causes or exacerbates a host of medical conditions, including cardiovascular, pulmonary, and endocrine diseases. Recently obesity in elderly women was associated with greater risk of dementia, white matter ischemic changes, and greater brain atrophy. The purpose of this study was to determine whether body type affects global brain volume, a marker of atrophy, in middle-aged men and women.     

Prey choice and cannibalistic behaviour in the theropod Coelophysis

Direct evidence of prey choice in carnivorous dinosaurs is rare in the fossil record. The most celebrated example pertains to purported stomach contents in the carnivorous dinosaur Coelophysis bauri, which besides revealing prey choice, also points to cannibalistic behaviour as being commonplace (Colbert 1989, 1995). Here, we test this hypothesis by conducting the first comprehensive anatomical and histological examination of the famed Coelophysis 'cannibals'. The results unequivocally show that the gut contents derive from early crocodylomorphs rather than juveniles of Coelophysis. These findings suggest that this taxon is not cannibalistic and bring into question the commonality of this behaviour among non-avian dinosaurs.     

JColorGrid: software for the visualization of biological measurements

Background  

Two-dimensional data colourings are an effective medium by which to represent three-dimensional data in two dimensions. Such "color-grid" representations have found increasing use in the biological sciences (e.g. microarray 'heat maps' and bioactivity data) as they are particularly suited to complex data sets and offer an alternative to the graphical representations included in traditional statistical software packages. The effectiveness of color-grids lies in their graphical design, which introduces a standard for customizable data representation. Currently, software applications capable of generating limited color-grid representations can be found only in advanced statistical packages or custom programs (e.g. micro-array analysis tools), often associated with steep learning curves and requiring expert knowledge.