A phenotype-based screen for embryonic lethal mutations in the mouse

The genetic pathways that control development of the early mammalian embryo have remained poorly understood, in part because the systematic mutant screens that have been so successful in the identification of genes and pathways that direct embryonic development in Drosophila, Caenorhabditis elegans, and zebrafish have not been applied to mammalian embryogenesis. Here we demonstrate that chemical mutagenesis with ethylnitrosourea can be combined with the resources of mouse genomics to identify new genes that are essential for mammalian embryogenesis. A pilot screen for abnormal morphological phenotypes of midgestation embryos identified five mutant lines; the phenotypes of four of the lines are caused by recessive traits that map to single regions of the genome. Three mutant lines display defects in neural tube closure: one is caused by an allele of the open brain (opb) locus, one defines a previously unknown locus, and one has a complex genetic basis. Two mutations produce novel early phenotypes and map to regions of the genome not previously implicated in embryonic patterning.     

A conceptual foundation for human suffering in nursing care and research

Suffering is a significant, yet elusive, phenomenon in nursing and health care. Despite the importance and prevalence of suffering, there is only a small body of substantive literature on this topic. Some of the difficulty in expanding this knowledge base undoubtedly is related to the lack of a solid conceptual foundation for exploration of this phenomenon. Although there have been attempts to provide needed conceptual clarity, these efforts typically have not been based on systematic inquiry. In this study, the method of concept analysis was used to inductively generate a definition of the concept of suffering and to clarify various contextual aspects of the concept. Suffering is defined as an individualized, subjective, and complex experience that involves the assignment of an intensely negative meaning to an event or a perceived threat. Implications of these findings and additional contextual aspects of the concept for nursing practice and inquiry are presented. These results help to provide the conceptual foundation needed to enhance recognition and understanding of the human experience of suffering.     

Non-compliance with treatment in patients suffering from schizophrenia: a study to evaluate possible contributing factors

In the decade since the clinical arrival of laparoscopic cholecystectomy, there have been gratifying improvements in imaging technology and instrumentation, and innovative techniques have evolved. Laboratory-simulator devices are available for basic skills exercises and can at least reasonably mimic the appearance of the gallbladder and some other organs or anatomic regions. Unfortunately, there is no satisfactory method to practice dealing with certain structural abnormalities or disease processes. Because of that, some operations will be particularly difficult and the outcomes will be favorable only with careful planning and capable execution. The experiences and skill level of the surgeon can be enhanced by appropriate mental preparation. As a result, the surgeon will have the opportunity to accomplish the task, both laparoscopically and safely, under circumstances that initially were thought to be inappropriate or impossible for laparoscopy.     

Lumbar lordosis measurement. A new method versus Cobb technique

STUDY DESIGN: A historic cross-sectional study of lumbar lordosis in 199 healthy individuals aged 1-30 years. OBJECTIVE: To evaluate the magnitude and rate of the development of the normal lumbar lordotic curve with age using two methods of measurement. SUMMARY OF BACKGROUND DATA: There is no agreement among spine physicians on the range of the normal lumbar lordotic curve. In certain conditions, such as a tethered spinal cord, a change in lordotic curve may indicate or even precede the onset of neurologic symptoms. Reliable measurements of the lumbar lordotic curve may aid in the early diagnosis and management of these conditions, before irreversible neurologic change ensues. METHODS: The lumbar lordotic curve was measured by the traditional Cobb technique and by a newly designed method, tangential radiologic assessment of lumbar lordosis. The data were subjected to the Morgan-Pitman test for correlated variances to observe which of the two methods was more reliable in measuring the magnitude and rate of change in the lumbar lordotic curve. RESULTS AND CONCLUSIONS: The rate of development of the lumbar lordotic curve appears to be nonlinear, increases during first year of life and during puberty, and reaches a plateau of approximately 50 degrees at maturity. The tangential radiologic assessment of lumbar lordosis method is more reproducible and more reliable in the lumbar lordotic curve, providing a smaller range of normal values (8 degrees-16 degrees less) than the Cobb method.