MR of focal liver lesions: comparison of breath-hold and non-breath-hold hybrid RARE and conventional spin-echo T2-weighted pulse sequences.

To compare liver lesion detection rates, tissue signal and noise data, and qualitative parameters for breath-hold (BH) and non-breath-hold (NBH) hybrid rapid acquisition with relaxation enhancement (RARE) and conventional spin-echo (CSE) T2-weighted (CSE-T2) MR sequences, 20 patients were imaged using all three sequences. Lesion detection rates were 73.5% for the CSE-T2 sequence and 81.1% and 88.6% for the BH-RARE and NBH-RARE sequences, respectively (P = .027). Mean lesion-to-liver signal-difference-to-noise ratio for the NBH-RARE sequence was 14.0 +/- 11.5, significantly greater than 9.8 +/- 7.8 obtained for the BH-RARE sequence (P = .050) and 9.0 +/- 6.2 obtained for the CSE-T2 sequence (P = .015). The NBH-RARE sequence demonstrated fewer artifacts and greater overall image quality compared to the CSE-T2 sequence. The NBH-RARE sequence is a useful alternative to the liver signal-difference-to-noise ratio and lesion detection rate and better overall image quality.

Origins and affinities of modern humans: a comparison of mitochondrial and nuclear genetic data.

To test hypotheses about the origin of modern humans, we analyzed mtDNA sequences, 30 nuclear restriction-site polymorphisms (RSPs), and 30 tetranucleotide short tandem repeat (STR) polymorphisms in 243 Africans, Asians, and Europeans. An evolutionary tree based on mtDNA displays deep African branches, indicating greater genetic diversity for African populations. This finding, which is consistent with previous mtDNA analyses, has been interpreted as evidence for an African origin of modern humans. Both sets of nuclear polymorphisms, as well as a third set of trinucleotide polymorphisms, are highly consistent with one another but fail to show deep branches for African populations. These results, which represent the first direct comparison of mtDNA and nuclear genetic data in major continental populations, undermine the genetic evidence for an African origin of modern humans.

Oxygen transport in the blood.

Knowledge of how oxygen is dissolved in the blood, transmitted through the bloodstream, and factors that affect oxygen delivery to body cells, is essential to the nursing management of the critically ill patient whose inherent physiologic mechanisms have been compromised by life-threatening illness. This article begins with a simplified review of respiration, progresses through a discussion of oxygen tension in the blood and hemoglobin transport of oxygen, and ends with a discussion of factors that affect the oxyhemoglobin dissociation curve.

Academic middle managers for baccalaureate nursing: work motivation and satisfaction.

Seventy-nine percent of academic middle managers for baccalaureate nursing reported that they did not plan to continue in their current management positions, or advance in academic leadership positions (George, 1981). This study examined the relationships between the job characteristics, a mediating variable "growth need strength", and the general job satisfaction and work motivation of academic middle managers for baccalaureate nursing. The sample was drawn from the population of academic middle managers for baccalaureate nursing in 126 colleges and universities across the United States that offer both baccalaureate and higher nursing degree programs. Sixty seven percent returned the Job Diagnostic Survey Short Form (JDSSF). The findings were interpreted through an examination of three analytical techniques: zero-order correlations, multiple regression, and multiple regression with interaction. Findings indicate that the dependent variable, "internal work motivation," can be measured in the population, but it cannot be predicted using the seven job characteristics measured by the JDSSF. The job characteristic autonomy was significant in predicting "general job satisfaction." General job satisfaction also proved to be some combination of security satisfaction and growth need satisfaction. both independent variables "autonomy" and "feedback from the job itself" were significant in predicting growth need satisfaction. As a mediating variable, "growth need strength" was not significant in predicting general job satisfaction in a linear model, nor was it significant when entered as an interactive term. However, the multiplicative model did increase, by four percent above the linear model, the amount of variance predictable in general job satisfaction.(ABSTRACT TRUNCATED AT 250 WORDS)