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K Sheehan

Publications and source records attributed to K Sheehan.

At least 19 recordsLinked to original sources
PubMed2000

Expression of a novel antigen, EEM-1, in the mouse embryo and embryonic stem cell-derived embryoid bodies.

A novel monoclonal antibody designated EEM-1 is described. EEM-1 recognizes an intracellular protein with an apparent molecular weight of >250 kDa. Expression of the EEM-1 antigen is largely confined to extra-embryonic membranes, but some expression does occur in the embryo. In the embryonic day 6 (E6) and E7 embryo it is expressed in visceral and parietal endoderm; later derivatives of these structures in the yolk sac are negative. The outer layer of the amnion also stains. Within the embryo proper, antigen is expressed in limited regions of the gut, kidney, and pancreas. EEM-1 is also expressed in embryonic stem (ES) cells differentiating in vitro. Undifferentiated ES cells do not express the antigen. Embryoid bodies (EBs) derived from ES cells have patches of EEM-1-positive cells on their surface at 2 days in culture. Older EBs have increasing numbers of positive cells which are confined to the surface. A special class of EBs, termed "cystic EBs," are covered by a cell layer which strongly express EEM-1 antigen. The EEM-1 antibody will be useful for investigating the development of extra-embryonic membranes and their counterparts in the ES cell in vitro model.

Animals↗
PubMed2000

Teenagers' perceptions of personal safety and the role of the emergency health care provider.

STUDY OBJECTIVE: We designed this study to determine the experiences, attitudes, and beliefs of teenagers regarding violence in their lives and to gain an understanding of the perceived role of the emergency health care professional. METHODS: A qualitative study involving 10-person focus groups was conducted in 4 cities representing urban/low socioeconomic and suburban/high socioeconomic areas. Participants were 14 or 15 years of age and were recruited from local community centers. Moderators were matched by sex to the teenagers, and groups were segmented by race and sex. A semistructured guide was developed to help facilitate the discussion. All groups were audiotaped and videotaped, and the tapes were reviewed by the investigators for reoccurring themes. RESULTS: A total of 140 adolescents (14 groups of 10) participated; one half were male. Urban teenagers expressed concerns about gangs, rape, and homicide; suburban teenagers were concerned about parental pressure and suicide. The teenagers expressed distrust of teachers, police officers, and doctors and felt safest with their parents. The emergency department was viewed as a confusing and frightening place, and participants believed that the role of the ED staff was to treat the patient's medical problem and not inquire or counsel about violence. CONCLUSION: All of the teenagers, regardless of socioeconomic status, were concerned about violence in their lives. All of the teenagers believed that the emergency department is not the place for patients to be counseled about safety and violence prevention. A better understanding of the problem of violence from the point of view of the teenager is important in refining an effective role for the emergency health care provider in adolescent violent injury prevention.

Adolescent↗
PubMed1999

Adapting the gang model: peer mentoring for violence prevention.

OBJECTIVES: This study assessed the effectiveness of an inner-city peer-mentoring program in modifying the attitudes and behaviors involving violence of preadolescent mentees. METHODS: In a case-matched cohort study involving 7- to 13-year-old children, 50 children enrolled in peer mentoring (case subjects) were compared with 75 control subjects. Case subjects were involved before enrollment in the community program in which the intervention occurred; control subjects lived in the same housing project and were matched with case subjects on age, sex, and census tract. A total of 19 community adolescents mentored the case subjects by designing and presenting violence prevention lessons. Two reliable self-report scales, Determining our Viewpoints of Violent Events and Normative Beliefs About Aggression Scale, were used to measure attitudinal change. Teachers completed the Revised Behavior Problem Checklist to assess changes in behavior. RESULTS: At baseline, the survey scores of the case and control subjects were not different. After the intervention period, the case scores indicated less support for violence than the control scores. Case behavior scores did not change, but control behavior scores worsened. CONCLUSIONS: The data suggest that peer mentoring for younger children may be an important component of efforts to reduce youth violence. A larger multisite trial is warranted.

Adolescent↗
PubMed1998

Postpartum coma.

Explore the source record for details and available documents.

Adult↗
PubMed1998

A comparative study on the efficacy of CD8-positive cells in enhancing allogeneic bone marrow engraftment: cell sorting vs microbead selection.

We have used a superparamagnetic microbead selection system to positively select a murine bone marrow CD8+ cell population. The functional ability of these cells to enhance allogeneic bone marrow engraftment was compared with that of fluorescence activated cell sorter purified CD8+ cells. The CD8+ cell population prepared by the microbead selection procedure was as effective as cell sorter purified CD8+ cells in enhancing T cell-depleted allogeneic bone marrow engraftment in lethally irradiated mice. Phenotypic characterization of these cells shows that most of these CD8+ cells express CD3 and the T cell antigen receptor complex.

Animals↗
PubMed1997

Thrombopoietin is synthesized by bone marrow stromal cells.

We have previously characterized stromal progenitor cells contained in fetal bone marrow by fluorescence-activated cell sorting (FACS) using the differential expression of CD34, CD38, and HLA-DR, and found that a small number were contained within the CD34(+) cell fraction. In the present study, the frequency of stromal progenitors in both the CD34+ and CD34- subpopulations from samples of fetal and adult bone marrow was approximately one in 5,000 of the mononuclear cell fraction. Using multiparameter single-cell sorting, one in 20 fetal bone marrow cells with the CD34+, CD38-, HLA-DR-, CDw90+ phenotype were clonogenic stromal progenitors, whereas greater than one in five single cells with the CD34-, CD38-, HLA-DR-, CDw90+ phenotype formed stromal cultures. We found that cultures initiated by hematopoietic and stromal progenitors contained within the CD34+ fraction of bone marrow cells formed mixed hematopoietic/stromal cell cultures that maintained the viability of the hematopoietic progenitor cells for 3 weeks in the absence of added hematopoietic cytokines. We characterized some of the hematopoietic cytokines synthesized by stromal cultures derived from either CD34+ or CD34- bone marrow cells using reverse transcriptase-polymerase chain reaction (RT-PCR) amplification of interleukin-3 (IL-3), stem cell factor (SCF), CD34, Flt3/Flk2 ligand (FL), and thrombopoietin (TPO) mRNA sequences. We found ubiquitous expression of TPO mRNA in greater than 90% of stromal cultures initiated by either CD34+ or CD34- cells, and variable expression of SCF, FL, and CD34 mRNA. In particular, SCF and CD34 mRNA were detected only in stromal cultures initiated by CD34+ bone marrow cells, although the differences between CD34+ and CD34- stromal cells were not statistically significant. IL-3 mRNA was not found in any stromal cultures. An enzyme-linked immunosorbent assay (ELISA) of soluble SCF and TPO present in culture supernatants demonstrated that biologically significant amounts of protein were secreted by some cultured stromal cells: eight of 16 samples of conditioned media from stromal cultures initiated by fetal and adult bone marrow contained more than 32 pg/mL SCF (in the linear range of the ELISA), with a median value of 32 pg/mL (range, 9 to 230), while 13 of 24 samples of conditioned media had more than 16 pg/mL TPO (in the linear range of the ELISA), with a median of 37 pg/mL (range, 16 to 106). Our data indicate that stromal cultures initiated by single bone marrow cells can make FL, SCF, and TPO. Local production of early-acting cytokines and TPO by stromal cells may be relevant to the regulation of hematopoietic stem cell self-renewal and megakaryocytopoiesis in the bone marrow microenvironment.

Adult↗
PubMed1997

Children's exposure to violence in an urban setting.

OBJECTIVE: To assess the exposure to violence of a representative sample of children living in an inner-city public housing development. DESIGN: Self-report survey. SETTING: Chicago public housing development that covers 4 census tracts; population, 95% African American, 75% below the poverty level. PARTICIPANTS: One hundred forty-six African American youth, aged 7 through 13 years, completed the survey; 53% were male, mean and median ages, 11 years. Seventy-two children (case subjects) are involved in a community-based health and recreation program. They completed the survey prior to participating in a peer-mentoring violence prevention curriculum. The other 74 children (control subjects) were recruited by a community member going door to door. Control subjects were matched to case subjects for age, sex, and census tract. RESULTS: The case and control subjects were similar in their exposure to violence and so were grouped for analysis. Of the 146 children, 42% had seen someone shot and 37% had seen someone stabbed; 21% lived with someone who had been shot and 16% lived with someone who had been stabbed. Forty-seven percent of the girls and 55% of the boys had witnessed violence (P > .25). Almost all subjects (90%) felt safe at home. Two thirds (65%) of the children were not afraid to play outside, but almost half (43%) worried about getting hurt at school. CONCLUSIONS: These data, which describe a representative sample of children from an inner-city housing project, confirm the results from older clinic- and school-based convenience samples. In this low-income community, children are frequently exposed to deadly violence. In contrast with other reports, girls here are not spared.

Adolescent↗
PubMed1996

Dexamethasone in bronchiolitis: a randomised controlled trial.

BACKGROUND: Although corticosteroids are commonly prescribed in the treatment of bronchiolitis, there is no evidence on the efficacy of these drugs in this disorder. We designed a randomised, double-blind, prospective study to assess the efficacy of dexamethasone in infants with bronchiolitis who require hospital management. METHODS: Infants younger than 12 months who had been admitted to hospital for an initial episode of wheezing, were randomly allocated intramuscular dexamethasone (1 mg/kg daily) or placebo, every 24 h for three doses. We excluded infants who were younger than 4 weeks, who required admission to the intensive care unit, or who had a history of congenital heart disease, mechanical ventilation, or supplemental oxygen use. We assessed infants on admission and every 12 h thereafter--vital signs were taken, severity of accessory muscle use and wheezing were measured by a clinical severity score, and pulse oximetry in room air was done. Our primary endpoints were the time to resolution of symptoms--defined as the number of assessments needed to reach oxygen saturation of more than 95% while receiving no supplemental oxygen, an accessory muscle score of 0, a wheeze score of 0 or 1, and resumption of normal feeding--and duration of oxygen therapy. Follow-up assessments were made 10-14 days after discharge by telephone. We used a proportional-hazards model for our survival analysis. FINDINGS: 197 infants presented with bronchiolitis that required inpatient management. 75 were not enrolled (31 no consent, 28 no approach made, 16 transferred elsewhere). Of the 122 enrolled, four were excluded (clinical deterioration, diagnosis of cystic fibrosis, previous intubation, did not receive all study treatment). There were no differences between the dexamethasone (n = 65) and placebo-treated infants in demographic factors, exposure to tobacco smoke, duration of illness, presence of respiratory syncytial virus (RSV) antigen, respiratory rate, or severity score. More dexamethasone-treated patients had an initial oxygen saturation of 95% or less (51 [79%] dexamethasone vs 31 [59%] placebo, p = 0.02). There were no differences in duration of oxygen therapy (p = 0.74) or time to resolution of symptoms (p = 0.22). Stratification for presence of RSV antigen or family history of atopy did not affect the results. INTERPRETATION: Our findings do not support the use of dexamethasone in the treatment of bronchiolitis in infants.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1994

Anti-tumor necrosis factor modulates anti-CD3-triggered T cell cytokine gene expression in vivo.

De novo expression of TNF, IFN gamma, IL-3, IL-4, and IL-6 genes was initiated rapidly by treatment of mice with anti-CD3. A specific feature of this reaction was that TNF was derived exclusively from T cells. TNF was produced both as a mature soluble trimeric protein and as a 26-kD anti-TNF-reactive protein compatible with membrane-anchored TNF. Pretreatment with anti-TNF did not affect anti-CD3-triggered TNF mRNA expression in T cells. In contrast, in vivo and in vitro anti-TNF treatment upregulated anti-CD3-induced IFN gamma mRNA expression and inhibited IL-4 mRNA expression. These latter effects were not dependent on TNF neutralization: pretreatment with soluble recombinant 55-kD TNF receptor (TBPI) as an alternative TNF-neutralizing agent did not modify the anti-CD3-induced cytokine profile. These results suggest that a direct interaction between anti-TNF and T cell membrane-anchored TNF could account for the observed modulation of cytokine gene expression. The increased expression of INF gamma mRNA observed in anti-TNF-treated animals correlated with a decrease in IL-3 and IL-6 mRNA expression. Conversely, IFN gamma blockade by a neutralizing anti-IFN gamma mAb led to a substantial increase in both IL-3 and IL-6 gene expression induced by anti-CD3. Taken together, these results strongly argue for the existence, in the anti-CD3-induced cytokine cascade, of IFN gamma-dependent regulation of IL-3 production, which in turn modulates IL-6 production.

Animals↗
PubMed1994

Routine use of lamotrigine, a new anti-epileptic medication, and the value of measuring its blood levels.

Lamotrigine (LTG) has recently been approved for marketing in Australia as add-on therapy in resistant partial seizure disorders. Early reports cited a therapeutic blood level for LTG of 1-3 mg/L (4-12 mumol/L). Aspects of routine patient care with LTG, devoid of the restrictions of trial protocols, are discussed. Forty-five patients commenced therapy but 15 discontinued LTG. Of the remaining 30 patients, 9 became seizure free, 3 from the de novo trial in focal epilepsy and 6 with generalised epilepsy. Global evaluation of patients showed mild to moderate improvement for those with focal epilepsy and moderate to marked improvement for those with generalised epilepsy. Blood levels of LTG did not provide clinically useful information.

Adolescent↗
PubMed1991

Cascade modulation by anti-tumor necrosis factor monoclonal antibody of interferon-gamma, interleukin 3 and interleukin 6 release after triggering of the CD3/T cell receptor activation pathway.

In addition to being potent immunosuppressants, anti-CD3 monoclonal antibodies (mAb) are powerful mitogens in both humans and mice. The first antibody injection consistently induced an initial monocyte-dependent T cell activation with subsequent release of both monocyte- and T cell-derived cytokines [mainly tumor necrosis factor-alpha (TNF-alpha), interferon-gamma (IFN-gamma), interleukin (IL) 2, IL 3 and IL 6) into the circulation. This cytokine release is associated with a self-limiting, often severe, acute physical reaction in both patients and mice. We report here that a single injection of anti-TNF mAb prior to anti-CD3 administration not only neutralizes the biological activity of TNF but also strongly affects the release of other cytokines, with notably an up-regulation of IFN-gamma release and a down-regulation of IL 3 and IL 6 release. Conversely, pretreatment with anti-IFN-gamma mAb increases IL 3 and IL 6 production but does not affect TNF levels. Taken together, these data point to a pivotal role of IFN-gamma in the anti-CD3-induced cytokine cascade and reveal new regulatory pathways between TNF and IFN-gamma. With regard to the clinical implications of these findings, as anti-TNF mAb prevents anti-CD3-induced sickness in mice, whereas anti-IFN-gamma does not, such a therapeutic approach might be of value in OKT3-treated patients.

Animals↗
PubMed1991

Inter-mouse strain differences in the in vivo anti-CD3 induced cytokine release.

Triggering of the CD3 molecule by in vivo injection of the hamster anti-murine CD3 monoclonal antibody 145-2C11 in adult BALB/c mice leads to massive although transient T cell activation. High levels of tumour necrosis factor (TNF), interferon-gamma (IFN-gamma), IL-2, IL-3 and IL-6 are released into the circulation 1 to 8 h after a single 10 micrograms 145-2C11 i.v. injection. This release induces an impressive self-limited physical reaction associating hypothermia, hypomotility (as assessed by actimetry), diarrhoea, piloerection and even death when high doses (a single dose of greater than 100 micrograms/mouse injection) are administered. In vivo injection of 145-2C11 to other selected mouse strains, namely NZW, CBA/J and C3H/HeJ, induced both different cytokine release patterns and sickness. 145-2C11 induced significant release of TNF and IL-2 in all four strains. At variance, IFN-gamma was only detected in BALB/c mice sera which, in terms of physical reaction (hypothermia and hypomotility) were the most affected. Higher and long-lasting circulating IL-3/GM-CSF levels were present in CBA/J sera, correlating with a later recovery. These results underline heterogeneity in the in vivo cell activation pattern among different mouse strains, when triggering T lymphocytes via the CD3/Ti molecule as compared to exclusive targeting of monocyte/macrophages by means of lipopolysaccharide.

Animals↗
PubMed1990

Cytokine-related syndrome following injection of anti-CD3 monoclonal antibody: further evidence for transient in vivo T cell activation.

In vivo injection of the hamster anti-murine CD3 monoclonal antibody 145 2C11 into BALB/c mice induces a massive systemic release of several cytokines. Very high circulating levels of tumor necrosis factor are detected both by enzyme-linked immunosorbent assay and L-929 bioassay 90 min following a single injection of 10 micrograms/mouse 145 2C11. Peak circulating levels of exclusively T cell-derived products such as interferon-gamma, interleukin 2 and interleukin 3 are also detected 90 min to 8 h post-injection. Importantly, this cytokine release is transient since none of these cytokines are still present 12 to 24 h post-injection. In parallel to cytokine release, 145 2C11-treated mice (10 micrograms/mouse) exhibit somnolence, hypomotility (quantified by actimetry), hypothermia, diarrhea and piloerection. At this dosage, the physical reaction is not lethal and reverses in all mice by 48 h post-injection. Severe but again reversible anatomopathological changes are also observed: massive cellular depletion, necrosis and edema of lymphoid organs, leakage syndrome and inflammatory cell infiltrates of the lung, cell vacuolization, necrosis and vascular congestion of the liver. All these data are similar to the clinical and immunological manifestations of the OKT3-induced reaction in patients and, thus, provide an invaluable experimental tool to study its mechanisms and explore its prevention.

Animals↗
PubMed1990

Reduction of morbidity and cytokine release in anti-CD3 MoAb-treated mice by corticosteroids.

In keeping with the in vitro mitogenic properties of anti-CD3 MoAbs, the first injections of anti-CD3 are invariably responsible for an in vivo cellular activation. This activation induces a massive cytokine release in the circulation (TNF, IFN gamma, IL-2, IL-6, and IL-3). Paralleling this release, a severe clinical reaction occurs in OKT3-treated patients and in 145 2C11-treated mice. Corticosteroids both in vitro and in vivo inhibit the production of several cytokines involved in the anti-CD3 reaction. A single 1 mg hydrocortisone dose was administered to 145 2C11-treated mice according to different kinetics schedules. When given 1 hr prior to the anti-CD3 MoAb, hydrocortisone exerted a beneficial effect on the mouse physical reaction. Hypothermia was totally abrogated at the 4-hr time point. Diarrhea decreased by 50%. Hypomotility improved although not significantly. This improvement correlated with a major modification in the anti-CD3 pattern of cytokine release. At the 90-min blood withdrawal time point cytokine serum levels showed a 100% decrease for IFN gamma, an 88% decrease for IL-6, and 85% decrease for IL-2, and a 75% decrease for TNF. At 4 hr IL-2 serum levels were diminished by 65%; IL-6, IL-3, and IFN gamma serum levels were comparable to controls; and, interestingly, TNF was still detected, whereas it has already disappeared when 145 2C11 was administered alone. Importantly, when given more than 1 hr prior to anti-CD3 injection, corticosteroids were ineffective. To conclude, high doses of corticosteroids must be given with a precise kinetics--i.e. 1 hr prior to anti-CD3 MoAb--to achieve their maximal beneficial effect in the prevention of the anti-CD3 reaction.

Adrenal Cortex Hormones↗
PubMed1986

Decreased incidence of marrow graft rejection in patients with severe aplastic anemia: changing impact of risk factors.

Patients with severe aplastic anemia were conditioned with cyclophosphamide (200 mg/kg) and given marrow grafts from HLA-identical family members. Among 233 patients transplanted, 225 survived greater than or equal to 14 days and could be evaluated for engraftment. Forty-four of the 225 rejected their graft; 33 of these died and 11 survive. One hundred eighty-one patients had sustained engraftment; of these, 46 died and 135 survived. Binary logistic regression analyses revealed five risk factors for graft rejection: year of transplant, a large number of platelet transfusions, a positive relative response in mixed leukocyte culture, a low marrow cell dose, and omission of donor buffy coat cell infusion for transfused patients. These data show that patients transplanted recently had a lower likelihood of graft rejection than did patients transplanted in earlier years. Conceivably, this was related to changes in transfusion practices, but other factors as yet unidentified are likely to be involved. The data confirm that the largest possible number of marrow cells should be transplanted. Although the difference in the incidence of graft rejection between untransfused and transfused patients was not significant, it should be noted that transfused patients were given buffy coat cells. Because the addition of buffy coat cells results in a higher incidence of chronic graft-v-host disease (GVHD), it is still desirable to transplant patients with marrow alone early in their course before they have been transfused.

Anemia, Aplastic↗
PubMed1984

Cataracts after total body irradiation and marrow transplantation: a sparing effect of dose fractionation.

We examined 277 patients, who have been followed for 1 to 12 years after marrow transplantation, for cataract development. In preparation for transplantation, 96 patients with aplastic anemia were conditioned with chemotherapy only, usually cyclophosphamide 50 mg/kg X 4 intravenously, while 181 patients (two with aplastic anemia and 179 with a hematologic malignancy) were conditioned with a regimen of total body irradiation (TBI) and chemotherapy. TBI was delivered from two opposing 60Co sources at an exposure rate of 4 to 8 cGy/min, either as a single dose of 10 Gy (105 patients) or in fractions (76 patients), usually at increments of 2 to 2.25 Gy/day for 6 to 7 days for cumulative doses of 12 to 15.75 Gy. To date, 86 patients have developed cataracts. Kaplan-Meier product limit estimates of the incidence of cataracts for patients given chemotherapy only and no TBI, single-dose TBI, and fractionated TBI are 19, 80, and 18%, respectively. On the basis of proportional hazards regression analyses, patients given single-dose TBI had a relative risk of developing cataracts that was 4.7-fold higher than in patients given fractionated TBI or chemotherapy only (p less than 0.00005), suggesting a significant sparing effect with use of TBI dose fractionation. Addition significant risk factors included the chronic use of steroids posttransplant (highly associated with the presence of chronic graft-versus-host disease), and the diagnoses of acute lymphoblastic or chronic myelogenous leukemia.

Adolescent↗