BMP4 promotes formation of primitive vascular networks in human embryonic stem cell-derived embryoid bodies.

The vasculature develops primarily through two processes, vasculogenesis and angiogenesis. Although much work has been published on angiogenesis, less is known of the mechanisms regulating the de novo formation of the vasculature commonly called vasculogenesis. Human embryonic stem cells (hESC) have the capability to produce all of the cells of the body and have been used as in vitro models to study the molecular signals controlling differentiation and vessel assembly.

A study of the analytical behaviour of selected psycho-active drugs using liquid chromatography, ion trap mass spectrometry, gas chromatography and polarography and the construction of an appropriate database for drug characterisation.

This paper provides analytical chemical information on a range of psycho-active drugs. This analytical chemical information on liquid chromatography-electrospray ionisation-mass spectrometry (HPLC-ESI-MS), ion trap mass spectrometry (ESI-MS(n)), gas chromatography-flame ionisation detection (GLC-FID) and polarographic behaviour is then incorporated into a database which is of use in drug characterisation. Application is found in the determination of selected drug compounds in hair samples.

Frequency of the TMPRSS2:ERG gene fusion is increased in moderate to poorly differentiated prostate cancers.

Background: Recent reports indicate that prostate cancers (CaP) frequently over-express the potential oncogenes, ERG or ETV1. Many cases have chromosomal rearrangements leading to the fusion of the 5' end of the androgen-regulated serine protease TMPRSS2 (21q22.2) to the 3' end of either ERG (21q22.

Mammographic density and the risk and detection of breast cancer.

Background: Extensive mammographic density is associated with an increased risk of breast cancer and makes the detection of cancer by mammography difficult, but the influence of density on risk according to method of cancer detection is unknown.

Methods: We carried out three nested case-control studies in screened populations with 1112 matched case-control pairs. We examined the association of the measured percentage of density in the baseline mammogram with risk of breast cancer, according to method of cancer detection, time since the initiation of screening, and age.

Mammographic density: a hormonally responsive risk factor for breast cancer.

Mammographic density refers to radiologically dense breast tissue, and reflects variations in the tissue composition of the breast. It is positively associated with collagen and epithelial and non-epithelial cells, and negatively associated with fat. There is extensive evidence that mammographic density is a risk factor for breast cancer, independent of other risk factors, and is associated with large relative and attributable risks for the disease.

Human embryonic stem cells: challenges and opportunities.

Human and non-human primate embryonic stem (ES) cells are invaluable resources for developmental studies, pharmaceutical research and a better understanding of human disease and replacement therapies. In 1998, subsequent to the establishment of the first monkey ES cell line in 1995, the first human ES cell line was developed. Later, three of the National Institute of Health (NIH) lines (BG01, BG02 and BG03) were derived from embryos that would have been discarded because of their poor quality.

Body size, mammographic density, and breast cancer risk.

Background: Greater weight and body mass index (BMI) are negatively correlated with mammographic density, a strong risk factor for breast cancer, and are associated with an increased risk of breast cancer in postmenopausal women, but with a reduced risk in premenopausal women. We have examined the associations of body size and mammographic density on breast cancer risk.

Method: We examined the associations of body size and the percentage of mammographic density at baseline with subsequent risk of breast cancer among 1,114 matched case-control pairs identified from three screening programs.

Structural transitions and thermodynamics of a glycine-dependent riboswitch from Vibrio cholerae.

Riboswitches are complex folded RNA domains found in noncoding regions of mRNA that regulate gene expression upon small molecule binding. Recently, Breaker and coworkers reported a tandem aptamer riboswitch (VCI-II) that binds glycine cooperatively. Here, we use hydroxyl radical footprinting and small-angle X-ray scattering (SAXS) to study the conformations of this tandem aptamer as a function of Mg(2+) and glycine concentration.

Influence of patterns of hormone replacement therapy use and mammographic density on breast cancer detection.

Background: There is evidence that factors such as current hormone replacement therapy (HRT) use and mammographic density may each lower the sensitivity of mammography and are associated with a greater risk of developing an interval cancer. This study explores this relationship further by examining the influence of patterns of HRT use and the percentage of mammographic density on the detection of breast cancer by classification of interval cancer.

Methods: This study uses a case-case design nested within a cohort of women screened by the Ontario Breast Screening Program between 1994 and 2002.

Intervention with a low-fat, high-carbohydrate diet does not influence the timing of menopause.

Background: Later age at menopause is associated with a greater risk of breast cancer. Dietary factors may at least partially influence breast cancer risk through an effect on the age at menopause.

Objective: We studied the effect of a low-fat, high-carbohydrate (LFHC) dietary intervention on the timing of menopause in women with greater risk of breast cancer.

Does type of team matter? An investigation of the relationships between job characteristics and outcomes within a team-based environment.

The authors examined the relationship between team type (consultative or substantive); job characteristics; and the outcome variables of job satisfaction, satisfaction with team processes and activities, and team commitment. The present results supported the hypothesis that job characteristics mediate the relationship between team type and team commitment and partially mediate the relationship between team type and job satisfaction and satisfaction with team processes and activities. However, contrary to the hypothesis, consultative team members perceived the content of their jobs to be more enriched and reported higher levels of satisfaction and commitment than did substantive team members.

Mammographic density as a surrogate marker for the effects of hormone therapy on risk of breast cancer.

Background: Some types of hormone therapy increase both risk of breast cancer and mammographic density, a risk factor for the disease, suggesting that mammographic density may be a surrogate marker for the effects of hormones on risk of breast cancer. This research was undertaken to determine whether the effect of hormone therapy on breast cancer risk is mediated by its effect on mammographic density.

Methods: Individually matched cases and controls from three nested case-control studies in breast screening populations were studied.

The heritability of mammographically dense and nondense breast tissue.

Background: Percent mammographic density (PMD) is a risk factor for breast cancer. Our previous twin study showed that the heritability of PMD was 63%. This study determined the heritabilities of the components of PMD, the areas of dense and nondense tissue in the mammogram.

Extensor hallucis capsularis: frequency and identification on MRI.

Background: The extensor hallucis capsularis (EHC) is the most common name given to the accessory tendon sporadically seen medial to the extensor hallucis longus (EHL). We performed cadaver dissections and MRI evaluation to determine the frequency of its occurrence, the pattern of its origin and insertion, and its potential suitability as tendon graft.

Methods: The EHC was examined by dissection in 81 cadaver feet.

Pituitary growth hormone and growth hormone-releasing hormone receptor genes and associations with mammographic measures and serum growth hormone.

Background: Mammographic density is a strong risk factor for breast cancer that is heritable and associated with blood levels of growth hormone and insulin-like growth factor-I (IGF-I). We tested single nucleotide polymorphisms (SNP) in pituitary growth hormone (GH1) and growth hormone-releasing hormone receptor (GHRHR) genes for an association with mammographic density, hormones of the growth hormone/IGF-I axis, and anthropometric variables.

Methods: Mammograms from 348 women were measured using a computer-assisted method, blood collected, and DNA extracted.

Mammographic breast density as an intermediate phenotype for breast cancer.

The amount of radiologically dense breast-tissue appearing on a mammogram varies between women because of differences in the composition of breast tissue, and is referred to here as mammographic density. This review presents evidence that mammographic density is a strong risk factor for breast cancer, and that risk of breast cancer is four to five times greater in women with density in more than 75% of the breast than in women with little or no density in the breast. Density in more than 50% of the breast could account for about a third of breast cancers.

Mammographic breast density and cancer risk: the radiological view.

Breast density refers to the presence of fibroglandular tissue in the breast. Several investigators have demonstrated that extensive mammographic density is strongly associated with increased risk of breast cancer. Density can be assessed either subjectively or quantitatively.

The association of measured breast tissue characteristics with mammographic density and other risk factors for breast cancer.

Background: We have examined the relationships between the measured properties of breast tissue and mammographic density and other risk factors for breast cancer, using breast tissue obtained at forensic autopsy and not selected for the presence of abnormalities.

Methods: We used randomly selected tissue blocks taken from breast tissue slices obtained by s.c.

Simulated microgravity using the Random Positioning Machine inhibits differentiation and alters gene expression profiles of 2T3 preosteoblasts.

Exposure to microgravity causes bone loss in humans, and the underlying mechanism is thought to be at least partially due to a decrease in bone formation by osteoblasts. In the present study, we examined the hypothesis that microgravity changes osteoblast gene expression profiles, resulting in bone loss. For this study, we developed an in vitro system that simulates microgravity using the Random Positioning Machine (RPM) to study the effects of microgravity on 2T3 preosteoblast cells grown in gas-permeable culture disks.

Mammographic densities and breast cancer risk.

Variations between individuals in the radiographic appearance, or mammographic pattern, of the female breast arise because of differences in the relative amounts and X-ray attenuation characteristics of fat and connective and epithelial tissue. Studies using quantitative methods of assessment have consistently shown these variations to be strongly related to risk of breast cancer. Individuals with extensive areas of radiologically dense breast tissue on the mammogram have been found to have a risk of breast cancer that is four to six times higher than women with little or no density.

Marginal fit of leucite-glass pressable ceramic restorations and ceramic-pressed-to-metal restorations.

Statement Of Problem: Fabricating a feldspathic porcelain margin on a metal-ceramic restoration with a clinically acceptable marginal fit has proven to be a technique-sensitive procedure. Pressable ceramics are advocated to solve this problem.

Purpose: The purpose of this in vitro study was to compare the marginal adaptation of a pressable ceramic system when used with both all-ceramic and metal-ceramic crowns, with a traditional metal-ceramic restoration.

Association between the T27C polymorphism in the cytochrome P450 c17alpha (CYP17) gene and risk factors for breast cancer.

Mammographic density is associated with increased breast cancer risk and is influenced by sex hormones. A T27C polymorphism (alleles A1 and A2, respectively) in the 5' promoter region of CYP17 may be associated with elevated sex hormone levels. In a cross-sectional study of 181 pre- and 173 postmenopausal women, we examined the relationship of this polymorphism with mammographic density and other risk factors for breast cancer.

Inhibition of choroidal neovascularization by a peptide inhibitor of the urokinase plasminogen activator and receptor system in a mouse model.

Objectives: To determine the role played by the urokinase plasminogen activator (uPA) and urokinase plasminogen activator receptor (uPAR) system in choroidal neovascularization (CNV) and whether inhibition of this system can suppress the extent of CNV in an animal model.

Methods: Choroidal neovascularization was induced in mice by laser photocoagulation using the slitlamp delivery system. Reverse transcriptase-polymerase chain reaction and immunocytochemical analysis were performed on the retina choroids of these animals to examine the expression of uPAR.