In this task, you are given an abstract of article. Your task is to generate title for this article. Preferred titles are under thirty words.

Input: Consider Input: The recent availability in culture of embryo-derived pluripotential cells which exhibit both a normal karyotype and a high differentiative ability13 has encouraged us to assess the potential of these cells to form functional germ cells following their incorporation into chimaeric mice. We report here the results of blastocyst injection studies using three independently isolated XY embryo-derived cell lines (EK.CP1, EK.CC1.1 and EKCC1.2) which produce a very high proportion (>50%) of live-born animals that are overtly chimaeric. Seven chimaeric male mice, derived from these three lines, have, so far, proved to be functional germ-line chimaeras.

Output: Formation of germ-line chimaeras from embryo-derived teratocarcinoma cell lines

Input: Consider Input: PURPOSE To describe a naturally occurring X-linked recessive mutation, no b-wave (nob), that compromises visual transmission between photoreceptors and second-order neurons in mice.
METHODS Affected mice were identified by recording the light-evoked response of the retina, the electroretinogram (ERG). To evaluate visual transmission, cortical potentials were recorded with a scalp electrode. The inheritance pattern for nob was defined by breeding nob animals with normal mice. Retinal histologic analysis was performed by light microscopy.
RESULTS Although the photoreceptor-mediated ERG component (a-wave) was normal in nob mice, the major response component reflecting postreceptoral neuronal activity (b-wave) was missing. Visually-driven cortical activity was also abnormal in nob animals. At the light microscopic level, the nob retina appeared to have a normal cytoarchitecture.
CONCLUSIONS These findings suggest that the nob defect interferes with the transmission of visual information through the retina and that these mice are a useful model for the study of outer retinal synaptic function. In addition, this mutant mouse seems to provide an animal model for the complete form of congenital stationary night blindness, a human disorder in which patients have a profound loss of rod-mediated visual sensitivity.

Output: A naturally occurring mouse model of X-linked congenital stationary night blindness.

Input: Consider Input: Understanding which factors influence mammographically dense and nondense areas is important because percent mammographic density adjusted for age is a strong, continuously distributed risk factor for breast cancer, especially when adjusted for weight or body mass index. Using computer-assisted methods, we measured mammographically dense areas for 571 monozygotic and 380 dizygotic Australian and North American twin pairs ages 40 to 70 years. We used a novel regression modeling approach in which each twin's measure of dense and nondense area was regressed against one or both of the twin's and co-twin's covariates. The nature of changes to regression estimates with the inclusion of the twin and/or co-twin's covariates can be evaluated for consistency with causal and/or other models. By causal, we mean that if it were possible to vary a covariate experimentally then the expected value of the outcome measure would change. After adjusting for the individual's weight, the co-twin associations with weight were attenuated, consistent with a causal effect of weight on mammographic measures, which in absolute log cm(2)/kg was thrice stronger for nondense than dense area. After adjusting for weight, later age at menarche, and greater height were associated with greater dense and lesser nondense areas in a manner inconsistent with causality. The associations of dense and nondense areas with parity are consistent with a causal effect and/or within-person confounding. The associations between mammographic density measures and height are consistent with shared early life environmental factors that predispose to both height and percent mammographic density and possibly breast cancer risk.
Output: Predictors of mammographic density: insights gained from a novel regression analysis of a twin study.