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Biomedical subjects

C D Hillyer

Publications and source records attributed to C D Hillyer.

At least 19 recordsLinked to original sources
PubMed2001

Utilization of technologies to reduce allogeneic blood transfusion in the United States.

Concern over safety of the blood supply has led to the use of technologies to reduce allogeneic blood transfusion. The objective of this research was to determine the utilization of these technologies in the United States. We evaluated the following techniques: preoperative autologous donation (PAD), cell salvage (CS) and acute normovolemic haemodilution (ANH); and the following pharmaceuticals: aprotinin (APR), epsilon-aminocaproic acid (EACA), tranexamic acid (TXA), desmopressin (DDAVP) and recombinant human erythropoietin (EPO). In 1997, we conducted a cross-sectional mail survey of service chiefs at 1000 US hospitals randomly selected and stratified by status as a provider of open-heart surgery, geographical location and hospital bed size. Sixty-nine per cent (690) of hospitals responded to at least one of the four surveys sent to each hospital. Hospitals reported use of techniques more than pharmaceuticals (P < 0.001); PAD (83%, n = 206) and CS (82% n = 420) were used most frequently. Lack of familiarity was the most common reason cited for infrequent use of pharmaceuticals. Organizational characteristics (e.g. provision of open-heart surgery, size, geographical location, teaching status and type of hospital) were differentially associated with technology use. There is greater use of techniques than pharmaceuticals in US hospitals to reduce the need for allogeneic blood in the peri-operative setting. Providing open-heart surgery is strongly associated with the utilization of these technologies.

Biomedical Technology↗
PubMed2001

Multicenter evaluation of PCR methods for detecting CMV DNA in blood donors.

BACKGROUND: CMV DNA screening may be a useful adjunct to serologic tests in distinguishing potentially infectious blood donations from those that are "CMV-safe." However, there is currently no consensus on the optimal assay method for accurate detection of CMV DNA in donors. STUDY DESIGN AND METHODS: A blinded multicenter evaluation of seven CMV PCR assays was performed by five laboratories by using coded sets of analytical controls and donor blood samples. RESULTS: Five assays displayed sufficient sensitivity for donor screening, as judged by consistent detection of a minimum of 25 CMV genome equivalents (geq) in analytical controls constructed to contain from 1 to 100 CMV geq in background DNA from 250,000 cells, while the other two assays displayed inadequate sensitivity. Three sensitive assays, two based on nested PCR directed at the UL93 and UL32 regions of the CMV genome and another test (Monitor Assay, Roche), did not detect CMV DNA in samples from any of 20 pedigreed CMV-seronegative, Western blot-negative (S-/WB-) donors. Two other assays based on nested PCR occasionally detected CMV DNA in S-WB- samples, and one sensitive nested PCR assay directed at UL123 detected CMV DNA in a large proportion (85%) of S-WB- samples. CONCLUSION: Seven CMV PCR assays currently used for research and/or diagnostic applications displayed marked variations in sensitivity, specificity, and reproducibility when applied to coded analytical and clinical control samples containing cellular DNA from the equivalent of 250,000 WBCs. These results will be useful in the selection of assays with performance characteristics appropriate to donor screening objectives. They may also help explain discrepant findings from previous studies that used PCR to determine CMV DNA prevalence in seronegative and seropositive blood donors.

AIDS-Related Opportunistic Infections↗
PubMed2000

In vitro and in vivo responses to interleukin 12 are maintained until the late SIV infection stage but lost during AIDS.

The in vitro proliferative responses of macaque peripheral blood mononuclear cells (PBMCs) to IL-12 appeared similar before and early after SIV infection, whereas macaque PBMCs sampled during symptomatic stages of SIV infection showed markedly decreased responses. IL-12 was administered to SIVmac239-infected rhesus macaques either during the asymptomatic or the AIDS stage of infection in efforts to evaluate the effect of this cytokine on immune responses, viral loads, and hematopoietic functions in vivo. IFN-gamma secretion levels induced during the asymptomatic or early symptomatic phase were similar to preinfection induced levels, whereas in later AIDS stages this response was lost. The constitutive levels of other measured cytokines were not affected by IL-12 administration in vivo. The frequency and activity of circulating NK cells were markedly enhanced at early stages but not at symptomatic stages of SIV infection. pCTL frequencies were enhanced at early symptomatic stages but not at late AIDS stages. Despite its immunomodulatory effect, IL-12 did not seem to exacerbate or inhibit the replication of SIV in vivo, or the frequency of circulating infected lymphocytes. IL-12 administration was associated with a significant yet subclinical and transient decrease in hematocrit and hemoglobin levels without evidence of hemolysis, hemodilution, or reduction in the frequency of colony-forming unit potential of bone marrow CD34+ cells. This phenomenon may be explained by a functional inhibition of differentiation rather than an altered generation of bone marrow precursors. Thus, these results suggest that IL-12 may benefit HIV-1-infected patients only as long as their immune system retains its capability to respond to cytokine stimulation.

Animals↗
PubMed2000

Indications for therapeutic plasma exchange at a university hospital and a regional blood center.

The AABB guidelines for therapeutic plasma exchange (TPE) are divided into four categories: I. TPE is "standard and acceptable therapy," II. "generally accepted," III. "insufficient evidence to evaluate efficacy," and IV. "data suggest no therapeutic efficacy." Since little is known about the implementation of these guidelines, and since the indications for TPE may vary, depending upon an institution's patient mix, this study reviewed the indications and their categories for two co-located institutions. A retrospective review of the indications for all patients undergoing TPE from January 1, 1994 to December 31,1997 at Emory University Hospital (EUH), a tertiary-care teaching hospital, and the American Red Cross (ARC), a regional blood center, using AABB criteria (ASFA criteria used when not rated [NR] by AABB) was conducted. Categories I/II represented 75% and 88% of cases (EUH and ARC, respectively), while Categories III/IV/NR (NR as used below is "not rated" by both AABB and ASFA criteria; n is number of patients) were 25% and 12% of indications, respectively (P =0.002). Cases at EUH (n=101) were I, 62%; II, 13%; III, 3%; IV, 13%; and NR, 9%. Cases at ARC (n=359) were I, 77%; II, 11%; III, 9%; IV, 0%; and NR, 3% (P<0.001). No Category IV patients underwent TPE at ARC (13% at EUH). Thrombotic thrombocytopenic purpura (TTP) was the most common indication for TPE at both centers. The majority of the procedures were "appropriate" (Categories III/); several disorders ( approximately 10%) for which TPE was utilized at both centers were NR by both AABB and ASFA guidelines. Indications for TPE may differ, depending on the type of requesting institution. Physicians requesting TPE for patients with disorders in Categories III/IV/NR should be more strongly encouraged to enter their patients into controlled trials to best evaluate the efficacy of TPE in inadequately-studied clinical situations. This might best be accomplished at university hospitals, where requests for Category III/IV/NR may be higher. A need exists for periodic updating of the AABB guidelines to include those diseases for which new information is available with regard to the potential therapeutic role of TPE.

Hospitals, University↗
PubMed2000

Hematopoietic response to lineage-non-specific (rrIL-3) and lineage-specific (rhG-CSF, rhEpo, rhTpo) cytokine administration in SIV-infected rhesus macaques is related to stage of infection.

The present study reports the hematopoietic response to the exogenous administration of recombinant rhesus interleukin-3 (rrIL-3) or a combination of recombinant human granulocyte colony-stimulating factor (rhG-CSF)/erythropoietin (Epo)/thrombopoietin (Tpo) at two different stages of SIV infection: Early-stage (n = 6, CD4 + > 1000/microl and mild splenomegaly) and late-stage (n = 6, CD4 + < 500/microl, progressive hepatosplenomegaly and/or weight loss). SIV-infected animals exhibited significantly impaired bone marrow (BM) and peripheral blood (PB) responses to both rrIL-3 and rhG-CSF/Epo/Tpo administration, as compared to historic controls. In addition, compared to early-stage SIV-infected animals, late-stage SIV-infected macaques demonstrated a more marked dysfunction, as assessed by PB and BM CD34 + content and clonogenic progenitors (colony-forming unit). Neither rrIL-3 nor rhG-CSF/Epo/Tpo administration during either early-stage or late-stage SIV infection increased the viral load, as assessed by bDNA assay. These data suggest that hematopoietic reserve and the response to various cytokines is decreased even in early-stage SIV infection, with the hematopoietic dysfunction progressing in parallel to SIV infection.

Animals↗
PubMed2000

Effects of UVB radiation on cytokine generation, cell adhesion molecules, and cell activation markers in T-lymphocytes and peripheral blood HPCs.

BACKGROUND: Immunomodulatory effects of UV light have increasingly become a focus in transfusion medicine, BMT and transplantation immunology. In the transplant setting, the use of UVB radiation may reduce or abolish T-cell activation without compromising either bone marrow (BM) engraftment or graft-versus-leukemia effect. In this study, BM and apheresis-derived peripheral blood HPCs were used to investigate the effects of UVB on colony-forming ability, CD34+ cell viability, and growth potential, as well as on the secretion of MNC cytokines and the expression of cell surface markers and adhesion molecules. STUDY DESIGN AND METHODS: After UVB radiation, enriched populations of T cells and antigen-presenting cells (APCs) were treated with PHA, and the MNC response was measured, as was colony-forming ability. CD34+ cells were quantified and their growth potential was determined in culture. Next, T-cell activation status, cell adhesion molecule and cell surface activation marker expression, and cytokine profiles were evaluated, and cytokine mRNA was quantitated. Parallel studies were done in unirradiated control cell populations. RESULTS: Low-dose (10 mJ/cm(2)) UVB mitigates MNC proliferative responses by 94 percent while maintaining 60 and 80 percent of colony-forming ability in peripheral blood HPC and BM preparations, respectively, and >50 percent of colony-forming ability in CD34+ cell-enriched samples. Low-dose UVB radiation also significantly reduces T-cell production of TNFalpha, TNFalpha mRNA, TNFbeta, IL-2, and IL-6 and downregulates T-cell expression of CD28, CD25, CD69, and intercellular adhesion molecule 1. CONCLUSION: These findings have shown that a "window" of low-dose UVB radiation (10 mJ/cm(2)) exists, at which BM- and peripheral blood-derived MNC proliferation is inactivated, while the HPCs are relatively spared. UVB light selectively affects T cells, while APCs are resistant to low doses of UVB. UVB radiation also alters the expression of some cell surface markers and cytokines that are important in T-cell activation pathways. Reduction of T-cell activation without cytocidal effect may allow UVB radiation to become an immunomodulating agent in BM or HPC transplantation.

Antigen-Presenting Cells↗
PubMed2000

Longitudinal monitoring of WBC subsets in packed RBC units after filtration: implications for transfusion transmission of infections.

BACKGROUND: Specific subsets of peripheral blood WBCs are reservoirs for infectious agents, such as CMV and EBV, and can serve as vectors for transfusion transmission of these agents. While filter WBC reduction has been used to prevent transfusion transmission of infections, its effectiveness has not been documented for many infectious agents and in some instances may be difficult to demonstrate in clinical trials. Because the effectiveness of filtration depends on the number of infected WBCs remaining at transfusion, WBC subpopulations in packed RBC units were quantitated after filtration and storage. STUDY DESIGN AND METHODS: Packed RBC units (n = 14) were filtered and stored at 4(o)C for 42 days or were stored without filtration. Serial samples were subjected to flow cytometric immunophenotyping of WBC subsets: neutrophils, monocytes, CD4+ and CD8+ T cells, B cells, and NK cells. RESULTS: Filtration produced a mean reduction in total WBCs of 3.2 log. Monocytes, lymphocytes, and neutrophils were reduced by 4.1, 3.8, and 2.5 log, respectively. Lymphocyte subsets also demonstrated differential reduction with filtration. All WBC subsets showed ongoing loss during storage. CONCLUSIONS: Monocyte and lymphocyte subsets are removed most effectively by prestorage filtration. Postfiltration storage leads to further significant reductions in WBC subsets. The implications of these findings for the mitigation of transfusion transmission of infection are discussed.

Antibodies↗
PubMed2000

The in vitro effects of antithrombin III on the activated coagulation time in patients on heparin therapy.

UNLABELLED: Heparin requires antithrombin III (AT) to achieve anticoagulation, and patients on continuous small-dose heparin preoperatively experience decreased levels of AT-causing heparin resistance. When this occurs, 2-4 units of fresh frozen plasma ( approximately 1000 units of AT) are often administered to increase AT levels and restore heparin responsiveness. We evaluated purified human AT concentrate (Thrombate III; Bayer, Inc., Elkhart, IN) to restore in vitro anticoagulation responses in patients receiving heparin. Blood samples were obtained from cardiac surgery patients including 22 patients receiving heparin and 21 patients not receiving heparin preoperatively. Heparin was added to blood in final concentrations of 4.1, 5.4, and 6.8 U/mL (equivalent to 300, 400, and 500 U/kg), and kaolin-activated clotting times (ACTs) were determined with and without AT at a final concentration of 0.2 units/mL to mimic fresh frozen plasma administration. The mean duration of preoperative heparin therapy was 4.0 days (range 2-10 days). AT activity was 69% +/- 9% in patients receiving heparin and 92% +/- 8% in patients not receiving heparin (P < 0.01). Heparin >4.1 U/mL failed to further increase ACT values in all patients. Attempts to increase ACT in patients receiving heparin may require supplemental AT administration. Purified AT even in small doses significantly prolongs the ACT response to heparin. IMPLICATIONS: In vitro addition of antithrombin III (0.2 U/mL) to heparinized blood samples (4.1-6.8 units of heparin/mL) from patients on previous heparin therapy increases sensitivity to supplemental heparin as reflected by significantly prolonged activated clotting time.

Aged↗
PubMed1998

Development of an animal model for autotransfusion therapy: in vitro characterization and analysis of anti-CD3/CD28 expanded cells.

Previous studies have shown that in vitro culture of human CD4+ T cells with antibodies to CD3 and CD28 immobilized on beads induced an antiviral effect to HIV-1 infection. Herein, we have used CD4+ T cells from nonhuman primates to address issues critical for use of such cells for therapy and immune reconstitution of humans and nonhuman primates infected with HIV and simian immunovirus (SIV). These studies include definition of the kinetics of the antiviral effect, the relative stability of the acquired phenotype, and whether such activated and expanded CD4+ T cells retain their immune function. Results of our studies show that antiviral effect is induced rapidly following activation with anti-CD3/CD28-coated beads. Additionally, the antiviral effect is not stable in these cells and requires continuous culture with anti-CD3/CD28 beads. Removal of CD4+ T cells from anti-CD3/CD28 stimulation renders these cells susceptible to infection, demonstrating that the resistant phenotype is not stable in these cultures. However, anti-CD3/CD28 expanded CD4+ T cells do retain immune function. Thus, although these findings imply a note of caution for therapeutic strategies aimed at providing patients with virus-resistant CD4+ T cells, the present study suggests that transfusion of such cells with retained immune function may have immune restoration capability.

Animals↗
PubMed1998

Molecular cloning and expression of rhesus macaque and sooty mangabey interleukin 16: biologic activity and effect on simian immunodeficiency virus infection and/or replication.

Interleukin 16 (IL-16) has been shown to diminish HIV and SIV replication through inhibition of HIV and SIV mRNA transcription. To evaluate its role further, we compared IL-16 cloned from disease-susceptible rhesus macaques and disease-resistant sooty mangabeys. Recombinant rhesus macaque (rr) IL-16 was compared with recombinant sooty mangabey (rm), human, and other nonhuman primate IL-16 sequences and evaluated for its ability to induce chemotaxis and inhibit the mixed lymphocyte response (MLR). Also, rrIL-16 and rmIL-16 were evaluated for suppression of SIVmac251, which replicates efficiently in T cells and monocyte/macrophages (dual tropic), and cloned SIVmac239, which replicates efficiently in T cells (T tropic). Sequence comparison of rrIL-16 and rmIL-16 with human IL-16 showed >97% amino acid identity. Biocharacterization of rrIL-16 revealed potent induction of chemotaxis (p < 0.05) and marked inhibition of MLR (73 +/- 0.6%,p < 0.05) in rhesus and human cell systems. Using rrIL-16 and rmIL-16, p27 antigen production from PBMCs infected with SIVmac251 was decreased up to 70% (p < 0.05 and p < 0.01, respectively). In similar cultures infected with SIVmac239, rrIL-16 and rmIL-16 reduced p27 levels by 96 and 100%, respectively. These data demonstrate the biologic and antiviral functionality of rrIL-16 and rmIL-16.

Amino Acid Sequence↗
PubMed1998

Hematologic and virologic effects of lineage-specific and non-lineage-specific recombinant human and rhesus cytokines in a cohort of SIVmac239-infected macaques.

The hematologic abnormalities of SIV and HIV are well described, although the mechanisms that lead to hematopoietic dysfunction are yet to be fully defined. A number of growth factors and cytokines have been used to induce the differentiation, maturation, and proliferation of appropriate lineages, with the aim that such therapy will lead to functional hematopoietic reconstitution. Within this context, some cytokines have been shown to influence HIV and SIV replication in vitro and, in selected cases, in vivo. However, few studies detail the effects of hematopoietic cytokines such as IL-3, Flt-3 ligand, G-CSF, Tpo, and Epo or correlate the effects on virus replication. In an effort to address this issue, we infected 12 rhesus macaques with 500 TCID50 of SIVmac239 and intensively evaluated hematologic, virologic, and immunologic parameters during administration of cytokines. When all animals had lymphadenopathy, hepatosplenomegaly, and CD4+ cell counts > or =1000/microl, subgroups of three rhesus macaques were administered either rhFlt-3; rrIL-3a; combination of rhG-CSF, rhTpo, and rhEpo (rhGET); or rrIL-12. Fourteen days of rhFlt-3 administration induced expansion of the bone marrow CD34+ cells and granulocyte-macrophage colony-forming units (GM-CFUs) and increased absolute peripheral blood CD34+ cells and total CFUs. Following rrIL-3 and rhGET administration absolute peripheral blood CD34+ cells and total CFUs increased. rhGET also increased granulocyte, platelet, and reticulocyte counts by day 14 of administration. Branched DNA and coculture assays did not demonstrate any significant change in viral load with any of the cytokines administered. These data suggest that SIV-infected rhesus macaques have the hematopoietic capability to expand and mobilize CD34+ and GM-CFU progenitors and formed elements at 6-8 months postinfection in response to various cytokines, without increasing viral load.

Animals↗
PubMed1997

Allogeneic bone marrow transplantation with matched unrelated donors for patients with hematologic malignancies using a preparative regimen of high-dose cyclophosphamide and fractionated total body irradiation.

Allogeneic bone marrow transplantation (BMT) from an HLA-identical sibling donor is effective therapy for patients with bone marrow failure states and those with hematologic malignancies. However, only a minority of them will have an HLA-identical sibling donor; unrelated donors, matched or partially mismatched, have been used successfully for patients lacking a related donor. Even though results with allogeneic transplants using unrelated donors are encouraging, the incidence of complications including graft-versus-host disease (GVHD) and graft rejection or late graft failure is increased compared to identical sibling transplants. The combination of cyclophosphamide and total body irradiation (TBI) has been used as an effective preparative regimen for allogeneic transplants, however, the total dosage and dosing schedule of both the cyclophosphamide and TBI has varied significantly among studies. To decrease the rate of graft rejection and late graft failure with volunteer donors, we evaluated a preparative regimen of high-dose cyclophosphamide (200 mg/kg over 4 consecutive days, days -8, -7, -6, -5) followed by fractionated TBI (1400 cGy administered in eight fractions over 4 days, days -4, -3, -2, -1). GVHD prophylaxis included FK506 and methotrexate. From July 1993 to January 1996, 43 adult patients, median age 38 years (range 18-58 years), were treated with this preparative regimen. Seventeen patients had low-risk disease and 26 had high-risk disease. Thirty-one donor/recipient pairs were matched for HLA-A, -B, and -DR by serology and molecular typing. Seven additional pairs were minor mismatched at the HLA-A or HLA-B loci. Four other donor/recipient pairs were HLA-A,-B, and -DR identical by serology but allele mismatched at either DRB1 or DQB. Forty patients were evaluable for myeloid engraftment. Engraftment occurred in all 40 patients at a median of 19 days. There were no cases of graft rejection or late graft failure. Nephrotoxicity was the primary adverse event with 26 patients (60%) experiencing a doubling of their creatinine. Hepatic veno-occlusive disease occurred in seven patients, six of whom had high-risk disease. All patients who had relapsed or refractory disease prior to BMT achieved a complete remission following BMT. Six patients transplanted for high-risk disease relapsed a median of 377 days post-BMT. None of the patients with low-risk disease have relapsed following transplant; the Kaplan-Meier survival for those patients with low-risk disease is 62% and 37% for those patients transplanted with high-risk disease (P = 0.0129). The median Karnofsky performance status is 100% (range 70-100%). Therefore, a preparative regimen of high-dose cyclophosphamide and fractionated TBI is an acceptable regimen for patients receiving an allograft from unrelated donors.

Adolescent↗
PubMed1997

The outcome of unrelated donor bone marrow transplantation in patients with hematologic malignancies using tacrolimus (FK506) and low dose methotrexate for graft-versus-host disease prophylaxis.

Initial studies of FK506 combined with methotrexate (MTX) in patients receiving unrelated donor BMT have demonstrated a possible-decrease in the incidence of severe GVHD but high rates of severe stomatitis and nephrotoxicity. With this background, we undertook a pilot study evaluating FK506 in combination with a lower than usual dose of MTX in an attempt to improve the tolerability of this immunoprophylaxis regimen. Between July 1993 and October 1994, 26 consecutive adults receiving unrelated donor BMT at Emory University Hospital were enrolled on this study. All patients received FK506 intravenously at an initial dose of 0.03 mg/kg/day beginning day -1 and continuing until oral FK506 was tolerated. Patients also received MTX intravenously at 5 mg/m2 on days 1, 3, 6, and 11. The preparative regimen administered to all but one patient included cyclophosphamide at 200 mg/kg over 4 days followed by total body irradiation (TBI) at 1400 cGy in twice daily fractions over 4 days. The median age of patients was 31 years (range: 19 to 52). Sixteen donor/recipient pairs were matched for HLA-A, -B, and -DR by serology and molecular typing. Ten paris were minor mismatches at either class I or class II. Twenty-two of 26 patients (85%) completed four doses of MTX on schedule. Nephrotoxicity was the most common adverse event associated with the administration of FK506: 88% of patients experienced a doubling of their serum creatinine. One patient died of central nervous system hemorrhage prior to engraftment. Twenty-four of the remaining 25 patients (96%) engrafted. Fourteen of 24 patients (50%) evaluable developed grades 2-4 acute GVHD. The rate of severe (grades 3-4) acute GVHD was 25%. Chronic GVHD developed in 11 of 20 (55%) evaluable patients. At a median follow-up of 461 days, 14 patients (54%) are alive. All are relapse-free with a median Karnofsky performance status of 90% (range: 70-100%). The cumulative probability of 2-year disease-free survival is 50% (95% confidence interval [CI]: 0.33 to 0.77); for low risk patients 67% (95% CI: 0.47 to 0.95) and for high risk patients 23% (95% CI: 0.049 to 1.00). These preliminary data indicate that FK506-based immunosuppression following unrelated donor BMT is effective in preventing severe acute GVHD and warrants comparison to CSA-based regimens.

Adult↗
PubMed1996

Peripheral blood progenitor cells for marrow reconstitution: mobilization and collection strategies.

Previous studies of PBPC BMR have found evidence supporting its safety, feasibility, and efficacy when used in a wide range of patients. Although the optimal regimen for mobilization remains a focus of debate, data from the use of combinations of chemotherapy and cytokines suggest that there is more rapid white cell and platelet engraftment than with BMT, which leads to decreased transfusion requirements and, possibly, reduced patient care costs. Recent advances in the field include allogeneic PBPC BMR, negative selection of tumor cells to reduce contamination, and positive selection of CD34+ cells. These new strategies are anticipated to enhance the therapeutic effectiveness of PBPC BMR while minimizing toxicity. Still, the ultimate comparison of PBSC BMR and medullary BMT will depend on the results of well-designed, randomized, controlled clinical trials with long-term outcome analysis. However, the refinement and improvement of mobilization and collection techniques for PBPC BMR continue to add to the armamentarium of current therapeutic approaches for cancer and related nonmalignant conditions and will enable future strategies for ex vivo expansion of progenitor cells and use in gene transfer studies.

Animals↗