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Biomedical subjects

E Donoghue

Publications and source records attributed to E Donoghue.

10 recordsLinked to original sources

Taxane containing regimens for metastatic breast cancer.

BACKGROUND: It is generally accepted that taxanes are among the most active chemotherapy agents in the management of metastatic breast cancer. OBJECTIVES: To identify and review the randomised evidence comparing taxane containing chemotherapy regimens with regimens not containing a taxane in the management of women with metastatic breast cancer. SEARCH STRATEGY: The specialised register maintained by the Editorial Base of the Cochrane Breast Cancer Group was searched on 2nd May 2003 using the codes for "advanced breast cancer", "chemotherapy". Details of the search strategy applied by the Group to create the register, and the procedure used to code references, are described in the Group's module on the Cochrane Library. SELECTION CRITERIA: Randomised trials comparing taxane-containing chemotherapy regimens with regimens not containing taxanes in women with metastatic breast cancer. DATA COLLECTION AND ANALYSIS: Data were collected from published trials. Studies were assessed for eligibility and quality, and data were extracted, by two independent reviewers. Hazard ratios were derived for time-to-event outcomes where possible, and a fixed effect model was used for meta-analysis. Response rates were analysed as dichotomous variables. Toxicity and quality of life data were extracted where present. MAIN RESULTS: Twenty one eligible trials were identified of which 12 have published time-to-event data and 16 have reported response data. The quality of randomisation was generally not described. An estimated 2621 deaths in 3643 randomised women demonstrate a statistically significant difference in favour of taxane-containing regimens with a HR for overall survival of 0.93 (95% CI=0.86-1.00, p=0.05) and no statistically significant heterogeneity. If the analysis is restricted to trials of firstline chemotherapy the HR changes to 0.92 and is no longer statistically significant (95% CI 0.84-1.02, p=0.11). There was also a significant difference in favour of taxanes in relation to time to progression (overall HR 0.92, 95%CI 0.85-0.99, p=0.02) and overall response in assessable women (overall OR 1.34, 95%CI 1.18-1.52, p<0.00001) however there was strong statistical evidence of heterogeneity (P<0.00001), probably reflecting the varying efficacy of the comparator regimens used in the trials. AUTHORS' CONCLUSIONS: When all trials are considered, taxane-containing regimens appear to improve overall survival, time to progression and overall response in women with metastatic breast cancer. The degree of heterogeneity encountered indicates that taxane-containing regimens are more effective than some, but not all non-taxane-containing regimens.

Antineoplastic Agents, Hormonal↗

Taxane containing regimens for metastatic breast cancer.

BACKGROUND: It is generally accepted that taxanes are among the most active chemotherapy agents in the management of metastatic breast cancer. OBJECTIVES: To identify and review the randomised evidence comparing taxane containing chemotherapy regimens with regimens not containing a taxane in the management of women with metastatic breast cancer. SEARCH STRATEGY: The specialised register maintained by the Editorial Base of the Cochrane Breast Cancer Group was searched on 2nd May 2003 using the codes for "advanced breast cancer", "chemotherapy". Details of the search strategy applied by the Group to create the register, and the procedure used to code references, are described in the Group's module on the Cochrane Library. SELECTION CRITERIA: Randomised trials comparing taxane-containing chemotherapy regimens with regimens not containing taxanes in women with metastatic breast cancer. DATA COLLECTION AND ANALYSIS: Data were collected from published trials. Studies were assessed for eligiblity and quality, and data were extracted, by two independent reviewers. Hazard ratios were derived for time-to-event outcomes where possible, and a fixed effect model was used for meta-analysis. Response rates were analysed as dichotomous variables. Toxicity and quality of life data were extracted where present. MAIN RESULTS: Twenty eligible trials were identified of which 17 had published at least some results, and 12 had published time-to-event data. The quality of randomisation was generally not described. An estimated 2659 deaths in 3643 randomised women demonstrate a statistically significant difference in favour of taxane-containing regimens with a HR for overall survival of 0.90 (95% CI=0.84-0.97, p=0.009) and no significant heterogeneity. If the analysis is restricted to trials of firstline chemotherapy the HR changes to 0.92 and is no longer statistically significant (95% CI 0.84-1.02, p=0.12). There was also a significant difference in favour of taxanes in relation to time to progression (overall HR 0.87, 95%CI 0.81-0.93, p<0.0001) and overall response (overall OR 1.29, 95%CI 1.13-1.47, p<0.0001) however there was strong statistical evidence of heterogeneity (P<0.00001), probably reflecting the varying efficacy of the comparator regimens used in the trials. REVIEWER'S CONCLUSIONS: When all trials are considered, taxane-containing regimens appear to improve overall survival, time to progression and overall response in women with metastatic breast cancer. The degree of heterogeneity encountered indicates that taxane-containing regimens are more effective than some, but not all non-taxane-containing regimens.

Antineoplastic Agents, Hormonal↗

Epitope mapping using the X-ray crystallographic structure of complement receptor type 2 (CR2)/CD21: identification of a highly inhibitory monoclonal antibody that directly recognizes the CR2-C3d interface.

Complement receptor type 2 (CR2)/CD21 is a B lymphocyte cell membrane C3d/iC3b receptor that plays a central role in the immune response. Human CR2 is also the receptor for the EBV viral membrane glycoprotein gp350/220. Both C3d and gp350/220 bind CR2 within the first two of 15-16 repetitive domains that have been designated short consensus/complement repeats. Many mAbs react with human CR2; however, only one currently available mAb is known to block both C3d/iC3b and gp350/220 binding. We have used a recombinant form of human CR2 containing the short consensus/complement repeat 1-2 ligand-binding fragment to immunize Cr2(-/-) mice. Following fusion, we identified and further characterized four new anti-CR2 mAbs that recognize this fragment. Three of these inhibited binding of CR2 to C3d and gp350/220 in different forms. We have determined the relative inhibitory ability of the four mAbs to block ligand binding, and we have used overlapping peptide-based approaches to identify linear epitopes recognized by the inhibitory mAbs. Placement of these epitopes on the recently solved crystal structure of the CR2-C3d complex reveals that each inhibitory mAb recognizes a site either within or adjacent to the CR2-C3d contact site. One new mAb, designated 171, blocks CR2 receptor-ligand interactions with the greatest efficiency and recognizes a portion of the C3d contact site on CR2. Thus, we have created an anti-human CR2 mAb that blocks the C3d ligand by direct contact with its interaction site, and we have provided confirmatory evidence that the C3d binding site seen in its crystal structure exists in solution.

Animals↗

Ethnic differences in mortality from insulin-dependent diabetes mellitus among people less than 25 years of age.

OBJECTIVE: To determine whether the risk of death from type 1 insulin-dependent diabetes mellitus (IDDM) was similar among young non-Hispanic black, non-Hispanic white, and Hispanic patients. DESIGN: Retrospective study of death certificates for Chicago residents between 1 and 24 years of age with any mention of diabetes during 1987 through 1994. Prevalence was estimated by an ongoing incidence registry in the city, the 1990 US Census, and published studies. Autopsy reports and/or medical records were examined to determine more clearly the circumstances of death. Case-fatality rates for IDDM in non-Hispanic black, non-Hispanic white, and Hispanic patients were calculated. Deaths in those with diabetes were compared with the mortality experience of the underlying population using race-specific standardized mortality ratios. RESULTS: A total of 30 diabetes-related deaths occurred in the 8-year interval: 23 among non-Hispanic black, 5 among Hispanic, and 2 among non-Hispanic white paients. The average annual case-fatality rate for all ethnic groups combined was 247.2/10(5) (95% CI: 166. 9-353.5). Race-specific rates were 447.8/10(5) (283.9-671.7) for non-Hispanic black patients, 175.6/10(5) (56.9-409.2) for Hispanic patients, and 48.2/10(5) (5.8-174.0) for non-Hispanic white patients; there were no gender differences in risk. A total of 8 individuals died at the onset of disease (7 non-Hispanic black patients and 1 Hispanic patient). Compared with the underlying population, ethnic-specific standardized mortality ratios were elevated significantly for non-Hispanic black and Hispanic patients but not for non-Hispanic white patients. CONCLUSIONS: Short-term mortality is elevated substantially among non-Hispanic black and Hispanic youth with IDDM. The ninefold greater risk of death for non-Hispanic black compared with non-Hispanic white youth with diabetes may indicate gaps in access to comprehensive diabetes care.

Adolescent↗

HIV envelope-directed signaling aberrancies and cell death of CD4+ T cells in the absence of TCR co-stimulation.

HIV-1 infection in CD4(+) T cells initiates a viral cytopathic effect (CPE) that is dependent on the activation of intracellular protein tyrosine kinases (PTK). PTK in T cells are also activated during the course of TCR or CD4 receptor engagement and the manner of receptor engagement may generate signals leading either to cell proliferation, tolerance induction (anergy) or programmed cell death (PCD). We have identified PTK triggered during the interaction of cells stably expressing surface HIV envelope (gp 120/gp41; HIVenv) and CD4(+)T cells, which leads to extensive and rapid individual cell death. We have found that killing is accompanied by tyrosine phosphorylation and activation of the CD4-associated p56(ICK) kinase, and by activation of a second member of the scr family of PTK, p59(fyn) kinase, normally associated with T cell stimulation through the TCR. Interestingly, in contrast with normal T cell signaling, the zeta subunit of the TCR fails to become tyrosine-phosphorylated during signaling accompanying HIV-directed cell killing. Downstream activation of the ZAP-70 PTK also does not occur. Unlike T cell apoptosis triggered by soluble HIVenv glycoproteins, which requires co-stimulation of CD4 and the antigen-specific TCR, T cell killing by membrane-associated HIVenv does not require TCR co-stimulation, because aberrant signaling and cell death are triggered by CD4(+) but TCR- cell lines. These results are the first report where dual activation of the Lck and Fyn PTK does not result in normal downstream signaling through the ZAP PTK, We suggest by analogy to SCID resulting from ZAP-70 mutations, that the dissociation of upstream PTK activation from ZAP-70 signaling contributes to T cell depletion by HIV and to the development of AIDS.

Apoptosis↗

Enhanced in vitro human immunodeficiency virus type 1 replication in B cells expressing surface antibody to the TM Env protein.

The human immunodeficiency virus type 1 (HIV-1) external envelope glycoprotein gp120 tightly binds CD4 as its principal cellular receptor, explaining the tropism of HIV-1 for CD4+ cells. Nevertheless, reports documenting HIV infection or HIV binding in cells lacking CD4 surface expression have raised the possibility that cellular receptors in addition to CD4 may interact with HIV envelope. Moreover, the lymphocyte adhesion molecule LFA-1 appears to play an important role in augmenting HIV-1 viral spread and cytopathicity in vitro, although the mechanism of this function is still not completely defined. In the course of characterizing a human anti-HIV gp41 monoclonal antibody, we transfected a CD4-negative, LFA-1-negative B-cell line to express an anti-gp41 immunoglobulin receptor (surface immunoglobulin [sIg]/gp41). Despite acquiring the ability to bind HIV envelope, such transfected B cells could not be infected by HIV-1. These cells were not intrinsically defective for supporting HIV-1 infection, because when directed to produce surface CD4 by using retroviral constructs, they acquired the ability to replicate HIV-1. Interestingly, transfected cells expressing both surface CD4 and sIg/gp41 receptors replicated HIV much better than cells expressing only CD4. The enhancement resided specifically in sIg/gp41, because isotype-specific, anti-IgG1 antibodies directed against sIg/gp41 blocked the enhancement. These data directly establish the ability of a cell surface anti-gp41 receptor to enhance HIV-1 replication.

Amino Acid Sequence↗