A skin abscess model for teaching incision and drainage procedures

Background  

Skin and soft tissue infections are increasingly prevalent clinical problems, and it is important for health care practitioners to be well trained in how to treat skin abscesses. A realistic model of abscess incision and drainage will allow trainees to learn and practice this basic physician procedure.     

Corpus callosum: interactive effects of infantile handling and testosterone in the rat

Previous research found that the corpus callosum of male rats is larger than that of females; handling rats in infancy enhances this sex difference; and female rat pups, when handled in infancy and given 1 injection of testosterone propionate (TP) on Day 4 of life, will have callosa as large as those of males. In 2 experiments, male pups were castrated on Day 1 or received sham surgery; female pups were injected with TP on Day 4 or received an oil injection. Litters were handled or nonhandled. The previous finding that females, when handled and given TP in infancy, have a larger callosum was confirmed; however, a TP effect when administered to nonhandled females was not found. Because handling is known to cause a corticosterone release, these findings were interpreted as evidence of a developmental interaction between adrenal and gonadal hormones at the cortical level.     

Bilateral transpedicular decompression and Harrington rod stabilization in the management of severe thoracolumbar burst fractures.

Fifty-eight patients with severe thoracolumbar burst fractures were treated with bilateral transpedicular decompression, Harrington rod instrumentation, and spine fusion. Spinal realignment and stabilization was achieved by contoured dual Harrington distraction rods supplemented by segmental sublaminal wiring. Posterior element fractures were noted in 25 patients, 9 of whom had associated dural tears. Computed tomography was performed to assess the cross-sectional area of the spinal canal before surgery and after decompression. Patients at initial evaluation averaged greater than 67% spinal canal compromise. After surgery, successful decompression was accomplished in 57 patients. One patient required staged, anterior thoracoabdominal decompression and fibula strut grafting. At follow-up (average, 43 months; range, 25-70 months), neurologic improvement was found in 77% of the patients who initially presented with neurologic deficits. Thirty-four of 40 patients with incomplete paraplegia improved one or more subgroups on the Frankel scale. A solid fusion was attained in all 58 patients. No patient had a significant residual kyphotic deformity. Single-stage bilateral transpedicular decompression and dual Harrington rod instrumentation reliably provides decompression of the spinal canal and restores spinal alignment. The procedure allows early mobilization and provides an environment for solid fusion and maximum neurologic return.     

Responsiveness of the cerebral circulation to acute alterations in mean arterial pressure during the administration of propofol

The responsiveness of the cerebral circulation to acute increases in mean arterial pressure was studied before and during the administration of propofol 3, 6, or 12 mg/kg/h in the anaesthetised baboon. Although mean arterial pressure increased significantly on each occasion, there were no significant changes in cerebral blood flow. This indicates that the physiological responsiveness of the cerebral circulation to alterations in mean arterial pressure was preserved during the administration of propofol in the concentrations studied.     

Requirements for activation of CD8+Murine T cells

Cytolytic effector function fails to develop if proliferation of allospecific cytolytic T lymphocyte precursors is inhibited, but the requirements for generation of cytolytic activity have not been fully defined. In contrast, the cytolytic effector function of cytolytic T lymphocyte clones does not change during the cell cycle, and the level of cytolytic activity is independent of cellular proliferation. The requirement for proliferation by primary responding populations may reflect the need for clonal expansion of a few inherently cytolytic effector cells in order to reach a threshold number which can readily be detected in conventional cytolytic assays. Alternatively, proliferation may be required for cytolytic T lymphocyte precursors to differentiate into mature, functional cytolytic cells. Using CD8+T cells which express an antigen-specific transgenic α/β T cell receptor, we have studied the requirements for acquisition of cytolytic capacity. Stimulation of the T cell receptor alone appears to be sufficient to render naive, CD8+ transgenic T cells sensitive to the growth effects of interleukin-2 (IL-2), and in some circumstances to interleukin-4 (IL-4), but not to induce either lymphokine production or cytolytic activity. Costimulatory molecules expressed by allogenic stimulating cells appear to be required for lymphokine production, and CD8+ transgenic T cells initially appear to secrete only IL-2 and interferon-γ. Stimulation of the T cell receptor of naive, CD8+ transgenic T cells appears to induce cytolytic activity only if cell proliferation occurs, either in response to IL-2 produced by the stimulated cells themselves when costimulatory molecules are present, or to IL-2 or IL-4 from exogenous sources if costimulatory molecules are absent.     

Multiple hemopoietic lineages are found after stimulation of mouse bone marrow precursor cells with interleukin 3

When the murine T-lymphocyte clone L2 is stimulated with concanavalin A, it secretes at least two distinct factors that affect hemopoietic precursor cells, interleukin 3 (IL3) and granulocyte/macrophage colony-stimulating factor (GM-CSF). IL3 accounts for approximately 10% of the colony-stimulating activity in L2-cell-conditioned medium. The IL3 secreted by L2 cells is similar antigenically to the IL3 secreted by WEHI-3 cells. Like the IL3 from WEHI-3 cells, IL3 secreted by L2 cells does not bind to DEAE Sephacel and can be separated from the L2-cell GM-CSF, which does bind to DEAE. By assessment of the functional, morphologic, surface phenotypic, and cytochemical characteristics of bone marrow cells 6 days after stimulation with IL3 in liquid culture, four hemopoietic lineages were found, including macrophage, neutrophilic granulocyte, megakaryocyte, and basophil/mast cell. In addition, when bone marrow cells were stimulated with IL3 in semisolid medium, several types of colonies were found, including mixed colonies containing macrophage, megakaryocyte, and granulocyte lineages.     

An estimate of the minimal frequency of cytolytic T lymphocyte effector cells generated in allogeneic reactions.

A 'micro' modification of the standard 51Cr release assay was developed. With this assay, significant cytolysis was obtained employing 100--200 51Cr-labeled target cells and fewer than 100 lymphocytes obtained from mixed leukocyte cultures. A minimal estimate as to the actual frequency of effector cells was determined for both primary (1 cell in 30) and secondary (1 cells in 8) cytolytic T lymphocyte populations.