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Biomedical subjects

Crystal Mackall

Publications and source records attributed to Crystal Mackall.

7 recordsLinked to original sources
PubMed2007

Treatment late effects in long-term survivors of pediatric sarcoma.

PURPOSE: To assess health and musculoskeletal function in survivors of pediatric sarcomas. PATIENTS AND METHODS: Thirty-two individuals treated for Ewing sarcoma family of tumors (ESFT), rhabdomyosarcoma (RMS), or non-rhabdomyosarcoma soft tissue sarcomas (NR-STS) with multi-modality therapy were enrolled on this cross-sectional study. Median age at the time of therapy was 15.4 years (range 7.1-34.2), median age at the time of analysis was 37.4 years (17.5-55.4), and median duration of time elapsed from completion of therapy was 17.3 years (2.9-32.6). Participants underwent assessments of musculoskeletal functioning, cardiac function, metabolic and lipid analyses, renal and gonadal function, and psychological evaluation. RESULTS: This cohort of sarcoma survivors shows expected locoregional limitations in function of the area affected by sarcoma, and impaired global musculoskeletal functioning as evidenced by limited endurance and limited overall activity levels. The cohort also demonstrated substantial rates of cardiac dysfunction, elevated body fat index, hyperlipidemia, chronic psychological distress, and infertility in men (76%) and premature menopause (49%) in women. CONCLUSION: Sarcoma survivors demonstrate diminished locoregional and global musculoskeletal functioning which likely limit occupational opportunities and socioeconomic health. In addition, the combination of diminished cardiac reserve, limited activity levels, and lipid dysregulation in sarcoma survivors suggests that this population is at increased risk for cardiovascular disease, even many years following completion of sarcoma therapy. Sarcoma survivors may benefit from life long follow-up for cardiovascular disease and from occupational counseling upon completion of therapy.

Adolescent↗
PubMed2006

Identification and epitope enhancement of a PAX-FKHR fusion protein breakpoint epitope in alveolar rhabdomyosarcoma cells created by a tumorigenic chromosomal translocation inducing CTL capable of lysing human tumors.

Fusion proteins created by chromosomal translocations in tumors can create neoantigenic determinants at the breakpoint, which are unique to the tumor cells but shared by the vast majority of tumors of that histologic type. If the fusion protein is responsible for the malignant transformation, its expression cannot be lost by the tumor to escape immune responses against this tumor antigen. Here, we identify such a fusion protein breakpoint epitope in the PAX-FKHR fusion protein created by the t(2;13) translocation present in 80% of cases of alveolar rhabdomyosarcoma, a highly aggressive pediatric soft-tissue sarcoma. We use autologous dendritic cells pulsed with the RS10 breakpoint fusion peptide to raise a human CTL line from a normal healthy HLA-B7+ blood donor specific for this peptide. These CTLs are CD8+ (CD4-CD56-) and restricted by HLA-B7. These human peptide-specific CTL lyse human HLA-B7+ rhabdomyosarcoma tumor cells. Therefore, the fusion protein is endogenously processed to produce this natural epitope presented by HLA-B7 and thus this peptide is a bone fide human tumor antigen. We also define a substitution that increases the affinity for HLA-B7 without loss of antigenicity. This epitope-enhanced peptide may serve as a candidate cancer vaccine for HLA-B7+ patients with alveolar rhabdomyosarcoma.

Amino Acid Sequence↗
PubMed2006

Functional outcomes and life satisfaction in long-term survivors of pediatric sarcomas.

OBJECTIVES: To describe the inter-relationships among impairments, performance, and disabilities in survivors of pediatric sarcoma and to identify measurements that profile survivors at risk for functional loss. DESIGN: Prospective, cross-sectional. SETTING: Research facility. PARTICIPANTS: Thirty-two participants in National Cancer Institute clinical trials. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Range of motion (ROM), strength, limb volume, grip strength, walk velocity, Assessment of Motor and Process Skills (AMPS); Human Activity Profile (HAP), Sickness Impact Profile (SIP), standard form of the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36); and vocational attitudes and leisure satisfaction. RESULTS: Twenty of 30 survivors tested had moderate or severe loss of ROM; 13 of 31 tested had 90% or less of predicted walk velocity; all of whom had trunk or lower-extremity lesions. Women with decreased ROM (r=.50, P=.06) or strength (r=.74, P=.002) had slow gait velocity. Sixteen of 31 tested were more than 1 standard deviation below normal grip strength. Eighteen had increased limb volume. These 18 had low physical competence (SF-36) (r=-.70, P=.001) and high SIP scores (r=.73, P=.005). AMPS scores were lower than those of the matched normed sample (P<.001). HAP identified 15 of 30 who had moderately or severely reduced activity. Leisure satisfaction was higher in the subjects (P<.001). Eight reported cancer had negatively impacted work and 17 reported that it negatively impacted vocational plans. CONCLUSIONS: Survivors with lower-extremity or truncal lesions and women with decreased ROM and strength likely have slow walk velocity, low exercise tolerance, and high risk for functional loss. They should be identified using ROM, strength, limb volume, and walk time measures.

Adolescent↗
PubMed2005

Thymic function in HIV infection.

Current models hold that CD4+ depletion occurs as a result of direct and indirect effects of HIV, which both kill peripheral CD4+ cells and prevent adequate regeneration. Although age-associated involution diminishes thymic reserve and HIV is clearly thymotoxic, clinical trials have nonetheless shown that large proportions of patients who sustain adequate control of viral replication with highly active antiretroviral therapy (HAART) will demonstrate some evidence for thymic-dependent immune reconstitution, which is associated with improved immune competence. Furthermore, patients with insufficient or absent immune reconstitution following HAART generally lack evidence for thymopoiesis. Current studies are focused on improving our understanding of the causes for thymic failure in HIV infection. Recent work has demonstrated that some HIV strains, especially those that are CXCR4 trophic, are more thymotoxic and may contribute to irreversible thymic damage in this population.

Antiretroviral Therapy, Highly Active↗
PubMed2004

Recombinant interleukin-7 induces proliferation of naive macaque CD4+ and CD8+ T cells in vivo.

Interleukin-7 (IL-7) regulates T-cell homeostasis, and its availability is augmented in lymphopenic hosts. Naive CD8+ T cells transferred to lymphopenic mice acquire a memory-like phenotype, raising the possibility that IL-7 is the biological mediator of this effect. Here, we provide direct evidence that IL-7 induces the acquisition of memory-cell markers not only in CD8+ T cells but also in CD4+ T-cell subsets in immune-competent Indian rhesus macaques. The increase of these memory-like populations was dependent on the dose of the cytokine, and these cells were found in the blood as well as secondary lymphoid organs. Memory-like CD4+ and CD8+ T cells acquired the ability to secrete tumor necrosis factor alpha and, to a lesser extent, gamma interferon following stimulation with a cognate antigen. The phenotypic change observed in naive T cells was promptly reversed after discontinuation of IL-7. Importantly, IL-7 induced cycling of both CD4+ and CD8+ central memory and effector memory T cells, demonstrating its contribution to the maintenance of the entire T-cell pool. Thus, IL-7 may be of benefit in the treatment of iatrogenic or virus-induced T-cell depletion.

Animals↗
PubMed2003

Neonates support lymphopenia-induced proliferation.

T cells expand without intentional antigen stimulation when transferred into adult lymphopenic environments. In this study, we show that the physiologic lymphopenic environment existing in neonatal mice also supports CD4 T cell proliferation. Strikingly, naive CD4 T cells that proliferate within neonates acquire the phenotypic and functional characteristics of memory cells. Such proliferation is inhibited by the presence of both memory and naive CD4 T cells, is enhanced by 3-day thymectomy, is independent of IL-7, and requires a class II MHC-TCR interaction and a CD28-mediated signal. CD44(bright) CD4 T cells in neonates have a wide repertoire as judged by the distribution of Vbeta expression. Thus, lymphopenia-induced T cell proliferation is a physiologic process that occurs during the early postnatal period.

Animals↗