BackgroundKnee osteoarthritis (KOA) is a prevalent form of chronic joint disease associated with functional restrictions and pain. Activity limitations negatively impact social connectedness and psychological well-being, reducing the quality of life (QoL) of patients. The purpose of this review is to summarize the existing information on QoL in KOA patients and share the reported individual factors, which may influence it.MethodsWe conducted a systematic review examining the literature up to JAN/2017 available at MEDLINE, EMBASE, Cochrane, and PsycINFO using KOA and QOL related keywords. Inclusion criteria were QOL compared to at least one demographic factor (e.g., age, gender), lifestyle factor (e.g., functional independence), or comorbidity factor (e.g., diabetes, obesity) and a control group. Analytical methods were not considered as part of the original design.ResultsA total of 610 articles were reviewed, of which 62 met inclusion criteria. Instruments used to measure QoL included: SF-36, EQ-5D, KOOS, WHOQOL, HAS, AIMS, NHP and JKOM. All studies reported worse QoL in KOA patients when compared to a control group. When females were compared to males, females reported worse QOL. Obesity as well as lower level of physical activity were reported with lower QoL scores. Knee self-management programs delivered by healthcare professionals improved QoL in patients with KOA. Educational level and higher total mindfulness were reported to improve QoL whereas poverty, psychological distress, depression and lacking familial relationships reduce it. Surgical KOA interventions resulted in good to excellent outcomes generally; although, results varied by age, weight, and depression.ConclusionKOA has a substantial impact on QoL. In KOA patients, QoL is also influenced by specific individual factors including gender, body weight, physical activity, mental health, and education. Importantly, education and management programs designed to support KOA patients report improved QoL. QoL data is a valuable tool providing health care professionals with a better comprehension of KOA disease to aid implementation of the most effective management plan.

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The production of mouse chimeras is a common step in the establishment of genetically modified animal strains. Chimeras also provide a powerful experimental tool for following cell behavior during both prenatal and postnatal development. This protocol outlines a simple and economical technique for the production of large numbers of mouse chimeras using traditional diploid morula<-->diploid embryonic stem (ES) cell aggregations. Additional steps are included to describe the procedures necessary to produce specialized tetraploid chimeras using tetraploid morula<-->diploid ES cell aggregations. This increasingly popular form of chimera produces embryos of nearly complete ES cell derivation that can be used to speed transgenic production or ask developmental questions. Using this protocol, mouse chimeras can be generated and transferred to pseudopregnant surrogate mothers in a 5-d period.

Tetraploid (4n) mouse embryos die at variable developmental stages. By examining 4n embryos from F2 hybrid and outbred mice, we show that 4n developmental potential is influenced by genetic background. The imprinted inactivation of an X chromosome-linked eGFP transgene in extraembryonic tissues occurred correctly in 4n embryos. A decrease of the cleavage rate in 4n preimplantation embryos compared to diploid (2n) embryos was revealed by real-time imaging, using a histone H2b:eGFP reporter. It has previously been known that mouse chimeras produced by the combination of diploid (2n) embryos with embryonic stem (ES) cells result in mixtures of the two components in epiblast-derived tissues. In contrast, the use of 4n host embryos with ES cells restricts 4n cells from the embryonic regions of chimeras, resulting in mice that are believed to be completely ES-derived. Using H2b:eGFP transgenic mice and ES cells, the behavior of 4n cells was determined at single cell resolution in 4n:2n injection and aggregation chimeras. We found a significant contribution of 4n cells to the embryonic ectoderm at gastrulation in every chimera analyzed. We show that the transition of the embryonic regions from a chimeric tissue to a predominantly 2n tissue occurs after gastrulation and that tetraploid cells may persist to midgestation. These findings suggest that the results of previously published tetraploid complementation assays may be influenced by the presence of tetraploid cells in the otherwise diploid embryonic regions.

Spontaneous duplication of the mammalian genome occurs in approximately 1% of fertilizations. Although one or more whole genome duplications are believed to have influenced vertebrate evolution, polyploidy of contemporary mammals is generally incompatible with normal development and function of all but a few tissues. The production of tetraploid (4n) embryos has become a common experimental manipulation in the mouse. Although development of tetraploid mice has generally not been observed beyond midgestation, tetraploid:diploid (4n:2n) chimeras are widely used as a method for rescuing extraembryonic defects. The tolerance of tissues to polyploidy appears to be dependent on genetic background. Indeed, the recent discovery of a naturally tetraploid rodent species suggests that, in rare genetic backgrounds, mammalian genome duplications may be compatible with the development of viable and fertile adults. Thus, the range of developmental potentials of tetraploid embryos remains in large part unexplored. Here, we review the biological consequences and experimental utility of tetraploid mammals, in particular the mouse. Developmental Dynamics 228:751-766, 2003.

Microscopy has always been an obligate tool in the field of developmental biology, a goal of which is to elucidate the essential cellular and molecular interactions that coordinate the specification of different cell types and the establishment of body plans. The 2008 Nobel Prize in chemistry was awarded 'for the discovery and development of the green fluorescent protein, GFP′ in recognition that the discovery of genetically encoded fluorescent proteins (FPs) has spearheaded a revolution in applications for imaging of live cells. With the development of more-sophisticated imaging technology and availability of FPs with different spectral characteristics, dynamic processes can now be live-imaged at high resolution in situ in embryos. Here, we review some recent advances in this rapidly evolving field as applied to live-imaging capabilities in the mouse, the most genetically tractable mammalian model organism for embryologists. Seeing is believingThe phenomenon of color has always fascinated researchers and academics of all disciplines. The discovery of fluorescent proteins (FPs) and the cloning of the first FP, wild-type green fluorescent protein (wtGFP), from the jellyfish Aequorea victoria [1] in the early 1990 s particularly excited life-scientists. Since then, FPs have proven a useful tool and made a tremendous impact on molecular biology. The original laboratory FP has served as a reagent for the production of many chemical modifications, producing, among other desirable features, spectral variants [2][3][4]. Other organisms, especially the Anthozoans (corals), have been exploited in the search for new FPs, with the desired properties focusing most of all on improved brightness but also on their excitation and emission spectra, monomerization, folding dynamics and reduced photobleaching [4][5][6]. GFP and its variants have remained the workhorse of lifescience investigations because, unlike other FPs, they have been shown to be non-toxic in vivo. GFP variants have been used to make ubiquitously and constitutively expressing transgenic plants or animals, such as worms, fruit flies, zebrafish, frogs and mice [7][8][9][10][11][12][13][14]. Since then, FPs have been applied in a variety of experimental settings, for example in promoter function studies [15,16], as fusion-protein tags to elucidate basic cellular functions [4,17] and in an organismal context for investigating tumor-host interactions [18,19].Combined with the imaging technology that is now available, FPs have become indispensable tools for exploring cellular function in real-time and at high resolution. It is widely recognized that genetic approaches are central in deciphering the roles of specific genes and gene networks operating during mouse embryonic development. However, a dynamic understanding of the early morphogenetic events that create the three-dimensional (3D) organization of the animal are lacking owing to the static nature of established protocols for dissecting spatially and temporally regulated events. Live imaging using FP r...

SummaryTo simultaneously follow multiple subcellular characteristics, for example, cell position and cell morphology, in living specimens requires multiple subcellular labels. Toward this goal, we generated dual-tagged mouse embryonic stem (ES) cells constitutively expressing differentially localized, spectrally distinct, genetically encoded fluorescent protein fusions. We have used human histone H2B fusions to fluorescent proteins to mark chromatin. This provides a descriptor of cell position, division, and death. An additional descriptor of cell morphology is achieved by combining this transgene with select lipid-modified fluorescent protein fusions that mark the plasma membrane. Using this strategy, we were able to live image cellular dynamics in three dimensions over time both in cultured ES cells and in mouse embryos generated using dual-tagged ES cells. This study, therefore, presents the feasibility of applying multiple spectrally and subcellularly distinct fluorescent protein reporters for live imaging studies in ES cells and mouse embryos. Furthermore, the increasing availability of spectral variant fluorescent proteins along with the development of methods that permit improved spectral separation now facilitate multiplexing of fluorescent reporters to provide readouts of a variety of anatomical and physiological behaviors simultaneously in living specimens. Keywordslive imaging; 3D time-lapse; confocal; fluorescent proteins; GFP; RFP; mCherry; embryonic stem cells; mouse embryo; chimera A sequence of stereotypical morphogenetic movements plays a pivotal role in building the developing embryo. A goal of developmental biology is to elucidate the cellular and molecular interactions that co-ordinate the specification of different cell types and the establishment of body plans, and to understand these interactions in the context of the global morphology of the embryo. Cell behaviors and motions in a living system are often complex and cannot be inferred with great accuracy from observations of static, sequentially staged images.The demonstration that green fluorescent protein (GFP) was amenable to use in heterologous systems has spearheaded a revolution in live imaging technology (Chalfie et al., 1994). Various bright, photostable, and developmentally neutral fluorescent proteins (FPs) with unique spectral properties are now available including enhanced GFP (EGFP) and its spectral variants (Heim et al., 1994;Heim and Tsien, 1996;Nagai et al., 2002 (Campbell et al., 2002;Shaner et al., 2004). Advances in optical imaging modalities and the continued evolution of these genetically encoded FPs is facilitating the study of cell behavior at high temporal and spatial resolution in living samples. Thus, coupled with genetics, live imaging and genetically encoded reporter strains represent an essential platform for acquiring quantitative information on dynamic cell behaviors and cell fate in vivo.Histological stains have traditionally been limited in functionality by the ability of the human eye to resolve multiple ...

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