Isolation of oligodendrocyte-like cells from human umbilical cord blood.

BACKGROUND: As human umbilical cord blood (UCB) is known to be a rich source of progenitor cells, the prospect of isolating a subset of these cells that could differentiate into cells of non-hematopoietic lineages suggests a therapeutic use for patients with inherited lysosomal and peroxisomal storage diseases currently treated with UCB transplantation. METHODS: Oligodendrocyte-like cells were isolated from UCB by density-gradient centrifugation and expanded using selective media. We then characterized this population of cells using standard immunohistochemical staining methods for neural cell proteins and polymerase chain reaction (PCR) to detect RNA sequences for myelin basic protein (MBP). We also developed a functional assay demonstrating myelination of neurons in vitro. RESULTS: Cells with oligodendrocyte-like morphology were reproducibly cultured ex vivo from fresh human UCB. Cells stained positively for multiple oligodendria cell markers (O1, MBP and CNPase) via immunohistochemical staining and flow cytometry. PCR confirmed the presence of MBP and CNPase mRNA. A further in vitro functional assay demonstrated the myelination of mature neuronal cells from the brain of a myelin-deficient murine model co-cultured with the oligodendrocyte-like cells. DISCUSSION: After human UCB transplant, donor-derived cells have been noted to migrate to the brain over time. Although is not known whether these cells solely deliver enzyme replacement or a subset engrafts and differentiates into mature neural cells, the clinical improvements noted in these patients suggest a potential role for targeted cellular therapy. Oligodendrocyte-like cells isolated ex vivo and expanded from human UCB could provide a potential cellular therapy for patients with demyelinating or dismyelinating diseases.

Comparison of the Simplify D-dimer assay performed at the bedside with a laboratory-based quantitative D-dimer assay for the diagnosis of pulmonary embolism in a low prevalence emergency department population.

BACKGROUND: The immunofiltration D-dimer assay could allow point-of-care testing for pulmonary embolism (PE). A study was undertaken to compare a clinician-performed qualitative D-dimer assay with the automated quantitative D-dimer test. METHODS: A prospective observational study was conducted from January to October 2005 at an urban academic emergency department (ED). 1193 patients of mean (SD) age 47 (16) years (66% female) were enrolled. The study protocol combined pretest probability estimation, D-dimer testing by both a qualitative immunochromatographic assay (Simplify) performed at the point of care by 192 different clinicians and a quantitative D-dimer test performed in a CLIA-certified laboratory. The criterion standard was image-proven PE or deep venous thrombosis within 45 days after enrollment. To test interobserver agreement for the qualitative assay, two blinded observers independently read 841 Simplify cartridges. RESULTS: Of 1193 patients enrolled, 45 were PE+ (3.8%, 95% CI 2.8% to 5.0%). Qualitative results were available for 1169 (98%) and quantitative results were available for 1136 (95%). Comparison of the qualitative and quantitative D-dimer tests gave the following results: sensitivity 91% (95% CI 78% to 98%) vs 93% (95% CI 80% to 98%); specificity 57% (95% CI 54% to 60%) vs 57% (95% CI 54% to 60%); likelihood ratio negative 0.16 (95% CI 0.06 to 0.37) vs 0.13 (95% CI 0.05 to 0.35). The weighted Cohen's kappa for interpretation of the qualitative assay was 0.69 (95% CI 0.63 to 0.76). CONCLUSIONS: In this very low-risk ED population, a qualitative D-dimer assay performed at the point of care had similar diagnostic accuracy to the quantitative D-dimer test. Interobserver agreement for the qualitative test was good.

RpoS-dependent stress response and exoenzyme production in Vibrio vulnificus.

Vibrio vulnificus is an estuarine bacterium capable of causing rapidly fatal infections through both ingestion and wound infection. Like other opportunistic pathogens, V. vulnificus must adapt to potentially stressful environmental changes while living freely in seawater, upon colonization of the oyster gut, and upon infection of such diverse hosts as humans and eels. In order to begin to understand the ability of V. vulnificus to respond to such stresses, we examined the role of the alternate sigma factor RpoS, which is important in stress response and virulence in many pathogens. An rpoS mutant of V. vulnificus strain C7184o was constructed by homologous recombination. The mutant strain exhibited a decreased ability to survive diverse environmental stresses, including exposure to hydrogen peroxide, hyperosmolarity, and acidic conditions. The most striking difference was a high sensitivity of the mutant to hydrogen peroxide. Albuminase, caseinase, and elastase activity were detected in the wild type but not in the mutant strain, and an additional two hydrolytic activities (collagenase and gelatinase) were reduced in the mutant strain compared to the wild type. Additionally, the motility of the rpoS mutant was severely diminished. Overall, these studies suggest that rpoS in V. vulnificus is important for adaptation to environmental changes and may have a role in virulence.

A survey of lightning policy in selected division I colleges.

OBJECTIVE: The purpose of this research was to investigate the hazards of lightning for participants in outdoor athletics and to determine the existence of, and assess the nature of, lightning safety policy at the collegiate level. DESIGN AND SETTING: We used data from the National Severe Storms Laboratory in Norman, Oklahoma, and from a survey of Division I institutions. SUBJECTS: The 48 National Collegiate Athletic Association Division I (football) universities in Florida, Michigan, Pennsylvania, North Carolina, and New York. MEASUREMENTS: Athletic trainers at all of the selected 48 Division I institutions responded to the telephone survey. RESULTS: Florida, Michigan, Pennsylvania, North Carolina, and New York led the country in lightning deaths and injuries from 1959-1994. Only 8% (n = 4) of the institutions surveyed in these states have a written policy regarding lightning safety. CONCLUSIONS: This study demonstrated the lack of lightning safety policy in the surveyed universities and the need for a systematic plan of action to make fields safer for all who are involved in outdoor sport activities.

Modified bar superstructure for an implant-retained orbital prosthesis.

The success of a bar superstructure for an orbital prosthesis may be compromised by the placement and angulation of implants. The following technique describes a modification to a bar superstructure that provided the advantages of convenience, security, and consistent positioning even though one implant was lost and the angulation of implants limited accuracy.

Clinical applications of a polyphosphazene-based resilient denture liner.

The use of resilient denture liners provides an invaluable modality in removable prosthodontic treatment. Treatment of atrophic mandibles, preoperative and postoperative soft tissue management, and retention of removable prosthesis are a few applications of these materials. This article describes the clinical application of a polyphosphazene-based liner (Novus, Hygenic Corp, Dayton, OH) as a denture liner and retentive material in conventional and implant overdenture rehabilitation.