A guide to risk assessment in animal care and use programs: the metaphor of the 3-legged stool.

A high-quality contemporary animal care and use program (ACUP) is a multifaceted dynamic system with three distinct organizational entities--the institutional official (IO), attending veterinarian (AV), and institutional animal care and use committee (IACUC)--each of whose authorities and responsibilities are mandated by a complex set of laws, regulations, policies, and guidelines. The 3-legged stool is presented here as a metaphor for the properly constituted and functioning ACUP, with the legs of the stool representing the IO, AV, and IACUC: when one component is weakened, the stool remains standing but tilts--the ACUP remains in compliance with animal welfare standards but is at risk of failure. Mechanisms for assessing an ACUP's strengths and weaknesses include both external evaluators, such as the US Department of Agriculture, Office of Laboratory Animal Welfare, and Association for Assessment and Accreditation of Laboratory Animal Care, and internal evaluators, such as the IACUC, AV, and IO.

The pylon concept of pelvic anchorage for spinal instrumentation in the human cadaver.

Study Design: Human cadavera morphometric analysis of the iliac columns and biomechanical implant testing of traditional Galveston technique compared to intrailiac instrumentation of the entire iliac column.

Objectives: To describe the anatomy of the iliac columns and to evaluate the strength in forward flexion of a large implant spanning the entire column length compared to standard Galveston technique.

Summary Of Background Data: We have observed substantial and straight columns of bone in the pelvis, connecting the acetabula to the sacrum, which may allow for improved spinopelvic instrumentation.

Development of the visual callosal cell distribution in the rat: mature features are present at birth.

In the present study, the early postnatal distribution and subsequent fate of visual callosal neurons were studied in neonatal rat pups. Previous studies had indicated that the adult pattern of visual callosal neurons was sculpted from an initially uniform distribution in the neonatal cortex. To reexamine this issue, we used a sensitive tracer, latex microspheres conjugated either to rhodamine or fluorescein, that was injected into the occipital cortex of one hemisphere in pups on the day of birth (PND 1), PND 6, or PND 12.

Distribution of visual callosal neurons in normal and strabismic cats.

It has been suggested that synchronous activation of cortical loci in the two cerebral hemispheres during development leads to the stabilization of juvenile callosal connections in some areas of the visual cortex. One way in which loci in opposite hemispheres can be synchronously activated is if they receive signals generated by the same stimulus viewed through different eyes. These ideas lead to the prediction that shifts in the cortical representation of the visual field caused by misalignment of the visual axes (strabismus) should change the width of the callosal zone in the striate cortex.