High-resolution voxelation mapping of human and rodent brain gene expression.

Voxelation allows high-throughput acquisition of multiple volumetric images of brain gene expression, similar to those obtained from biomedical imaging systems. To obtain these images, the method employs analysis of spatially registered voxels (cubes). For creation of high-resolution maps using voxelation, relatively small voxel sizes are necessary and instruments will be required for semiautomated harvesting of such voxels. Here, we describe two devices that allow spatially registered harvesting of voxels from the human and rodent brain, giving linear resolutions of 3.3 and 1 mm, respectively. Gene expression patterns obtained using these devices showed good agreement with known expression patterns. The voxelation instruments and their future iterations represent a valuable approach to the genome scale acquisition of gene expression patterns in the human and rodent brain.

Simultaneous molecular and anatomical imaging of the mouse in vivo.

Non-invasive imaging technologies are opening up new windows into mouse biology. We have developed a mouse imaging system that integrates positron emission tomography (PET) with x-ray computed tomography (CT), allowing simultaneous anatomic and molecular imaging in vivo with the potential for precise registration of the two image volumes. The x-ray system consists of a compact mini-focal x-ray tube and an amorphous selenium flat panel x-ray detector with a low-noise CMOS readout. The PET system uses planar arrays of lutetium oxyorthosilicate scintillator coupled to position-sensitive photomultiplier tubes. We describe the design of this dual-modality imaging system and show, for the first time, simultaneously acquired PET and CT images in a phantom and in mice.

Evaluation of a stereotactic frame for repositioning of the rat brain in serial positron emission tomography imaging studies.

For serial imaging studies of the rat brain with positron emission tomography (PET), reproducible positioning of the head can facilitate spatial alignment of images and quantitative analysis. To achieve this aim, we constructed a plastic head frame and tested the positioning reproducibility on a high-resolution small-animal PET scanner, microPET. Two sets of ear bars, with tapers of either 18 degrees (sharp) or 45 degrees (blunt), were evaluated for their relative precision in securing the animal to the frame. For sequential positioning of an animal, average distances from the mean position of 0.51 mm (SD 0.41 mm) and 0.91 mm (SD 0.48 mm) were measured with the sharp and blunt ear bars, respectively. These results show that a rat brain can be reproducibly positioned using the frame, with a variation of position less than the spatial resolution of modern animal PET scanners. Brain regions of interest defined on one scan and copied across subsequent scans of a frame-repositioned animal resulted in an average coefficient of variation of 5.4% (SD 2.7%) using the sharp ear bars and 6.8% (SD 2.5%) using the blunt ear bars. This methodology has the potential to improve quantitative assessment for serial PET studies.

The role of home care in integrated delivery systems.

The health care field is moving rapidly toward integrated delivery systems (IDS). The role of home care in such system is unclear. This study seeks to describe the current status of home care in IDS and to examine health care administrators' perceptions about the importance of IDS components. A random sample of 1600 administrators was surveyed, 400 each from home care agencies, hospitals, nursing homes, and medical groups. Results reveal that hospitals lead integration, nursing homes are least involved, and home care agencies and medical groups fall in between. Administrator's opinions vary considerably about the importance of select services and integrating mechanisms.

Tax exemption. Challenge and opportunity for not-for-profit hospitals.

As healthcare reform is debated over the next several years, not-for-profit hospitals will see increased challenges to their tax-exempt status. Over the past forty years, the requirements for maintaining a tax-exempt status have undergone numerous changes. In the last several years, several states have challenged the right of hospitals to maintain this desired status. As we move toward the mid-1990s, it will be critical for not-for-profit hospitals to demonstrate and communicate their commitment to charitable endeavors.

Hospital CEO turnover, 1987-1988: national, divisional, and class turnover rates.

This is the authors' third study of CEO turnover rates, the second to appear in Hospital Topics, and the most comprehensive study done so far. What is especially interesting for U.S. hospitals is that the 1987-1988 rate was the third successive year to decline--not yet a trend, but encouraging nonetheless.

Hospital chief executive officer turnover.

This study indicates that the nationwide CEO turnover rate is lower than many people estimate but was still, in 1987, an uncomfortable 22 percent on average. Some of this turnover may help some hospitals, for example, those with incompetent administrators. Some turnover may be natural in that some CEOs may have retired or died. Other turnover is controlled, such as that in the investor-owned sector where planned movement is expected. The analysis of the data in this study indicates that smaller hospitals experience higher turnover rates than do their larger counterparts. In 1987 Sun Belt and western hospitals experienced greater turnover than upper midwestern and eastern hospitals. As a group, however, the investor-owned sector led in turnover rates among hospital CEO turnover rates.