PubMed Health⌕ Search

Biomedical subjects

S Hoey

Publications and source records attributed to S Hoey.

7 recordsLinked to original sources
PubMed2000

An analysis of a preoperative pediatric autologous blood donation program.

OBJECTIVE: To determine the efficacy of a pediatric autologous blood donation program. DESIGN: A retrospective study of patient charts and blood-bank records. SETTING: The Children's Hospital of Eastern Ontario, Ottawa, a tertiary care, pediatric centre. PATIENTS: One hundred and seventy-three children who received blood transfusions for a total of 182 procedures between June 1987 and June 1997. INTERVENTIONS: Autologous and homologous blood transfusion required for major surgical intervention, primarily spinal fusion. MAIN OUTCOME MEASURES: Surgeons' accuracy in predicting the number of autologous blood units required for a given procedure, compliance rate (children's ability to donate the requested volume of blood), utilization rate of autologous units and rate of allogeneic transfusion. RESULTS: The surgeons' accuracy in predicting the number of autologous units required for a given procedure was 53.8%. The compliance rate of children to donate the requested amount of blood was 80.3%. In children below the standard age and weight criteria for blood donation the compliance rate was 75.5%. The utilization rate of autologous units obtained was 84.4% and the incidence of allogeneic transfusion was 26.6%. CONCLUSIONS: There was a high rate of compliance and utilization of predonated autologous blood in the children in the study. Preoperative blood donation programs are safe and effective in children, even in those below the standard age and weight criteria of 10 years and 40 kg.

Adolescent↗
PubMed1998

Concealable stigmas and positive self-perceptions: feeling better around similar others.

In an 11-day experience-sampling study, 86 Harvard undergraduates rated their momentary self-esteem and affect and then described the who, what, and where of their daily lives. Those with concealable stigmas (students who indicated that they were gay, that they were bulimic, or that their family earned less than $20,000 each year) reported lower self-esteem and more negative affect than both those whose stigmas were visible and those without stigmatizing characteristics. Only the presence of similar others lifted the self-esteem and mood of students with concealable stigmas, and these particular students were the least likely to experience such occasions. Thus, contact with similar others protects the psychological self from negative cultural messages.

Analysis of Variance↗
PubMed1997

Nitric oxide accelerates the onset and increases the severity of experimental autoimmune uveoretinitis through an IFN-gamma-dependent mechanism.

The production of large amounts of nitric oxide (NO) by inducible nitric oxide synthase (iNOS) has been described as a double-edged sword eliciting pro- or anti-inflammatory effects in different immune situations. Our aim, therefore, was to investigate its role in experimental autoimmune uveoretinitis (EAU), a model of ocular inflammation, induced in the Lewis rat following a single footpad injection of retinal Ags. iNOS enzyme was not detected in the normal Lewis rat eye, but was strongly expressed by infiltrating ED1+ macrophages during the acute inflammatory stages of EAU. Treating immunized animals with L-arginine increased urinary NO metabolite (NOx) levels, accelerated the inflammatory response, and increased disease severity, whereas treatment with the NOS inhibitor, N(G)-nitro-L-arginine methyl ester, reduced NOx excretion, delayed the onset, and reduced the clinical signs of EAU. Reverse transcription-PCR analysis of ocular tissue from untreated and treated animals detected iNOS mRNA at all stages of disease, and expression was up-regulated during peak disease. L-arginine treatment enhanced cytokine mRNA expression, particularly of IFN-gamma, which was detected earlier than in control animals, corresponding with the more rapid onset of disease and increased disease severity observed in this group. N(G)-nitro-L-arginine methyl ester had little or no effect on iNOS or inflammatory cytokine mRNA expression. These results suggest NO is central to the pathogenesis of EAU and highlight the importance of the macrophage as an effector cell in what is considered a CD4+ T cell-dependent disease. Furthermore, this study demonstrates the therapeutic potential of NOS inhibitors in the treatment of inflammatory and autoimmune mediated disease.

Animals↗
PubMed1996

CD59 and CD48 expressed by rat retinal pigment epithelial cells are major ligands for the CD2-mediated alternative pathway of T cell activation.

The alternative CD2-mediated pathway of T cell activation, which is independent of MHC/peptide recognition by the TCR/CD3 complex, is dependent upon two signals being received by the CD2 molecule. The natural ligand for CD2 is CD58, but controversy exists over alternative or additional ligands that could deliver the second signal in vivo. We have used rat retinal pigment epithelial cells (RPE), which lack temperature-insensitive ligands for CD2 adhesion, to study Ag-independent T cell activation. Rat RPE cells expressed high levels of CD59 and low levels of another potential CD2 ligand, CD48, both in vitro and in the in vivo model of experimental autoimmune uveoretinitis. When increasing numbers of syngeneic T cells were added to microwell cultures of rat RPE cells, the T cells, even in the absence of any exogenous stimulant in the cultures, underwent spontaneous proliferation. This effect required metabolically active RPE cells, and was IL-2 driven and enhanced in the presence of indomethacin. Proliferation was modulated by phosphatidylinositol-phospholipase C treatment of the RPE, and blocked by mAbs to CD59. Ab cross-linking of CD48 but not CD59 on the RPE was found to induce messenger RNA expression for IL-1 beta, which together with constitutively expressed IL-6 are required costimulatory factors for T cell activation through CD2. This is the first demonstration in a fully syngeneic system that bi-directional signaling involving CD59 and CD48 molecules expressed by physiologically normal, nonhematopoietic, cells can trigger T lymphocyte activation and proliferation through autocrine IL-2 production in the absence of Ag.

Animals↗
PubMed1988

Cellular response to oxidative stress at sulfhydryl group receptor sites on the erythrocyte membrane.

Ellman's reagent was used to induce an oxidative stimulus on the exofacial membrane sulfhydryl groups of the human erythrocyte. Thiol-disulfide exchange occurring extracellularly was monitored using resonance Raman spectroscopy, and intracellular changes were observed by 1H spin echo nuclear magnetic resonance spectroscopy of the intact cell. The stimulus caused oxidation and depletion of the glutathione pool, which was followed at higher concentrations of Ellman's reagent by a depletion of intracellular ergothioneine levels. Larger changes are induced intracellularly than would be expected from the stoichiometry of the reaction at the exofacial surface. A mechanism is proposed which links exofacial sulfhydryl receptor sites via the transport proteins to spectrin and glutathione. The consequences for the cellular redox balance of an extracellular stimulus of this type are discussed.

Blood Glucose↗
PubMed1988

Resonance Raman spectroscopy of hemoglobin in intact cells: a probe of oxygen uptake by erythrocytes in rheumatoid arthritis.

Resonance Raman spectra from intact viable erythrocytes can be used to study oxygen uptake in solution. In addition to changes in the oxidation state marker (nu 4), other bands due to the porphyrin ring (nu 3) and vinyl modes indicate subtle changes at oxygen pressures close to where the T/R change occurs. A comparison of whole cell and lysate spectra indicates a partial denaturation of hemoglobin on lysis. A simple smear technique is used to measure spectra from rheumatoid and normal blood. Results indicate a faster but less complete uptake of oxygen in cells from patients with rheumatoid arthritis than is the case in normal cell populations.

Arthritis, Rheumatoid↗