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M Little

Publications and source records attributed to M Little.

At least 37 records · Page 2Linked to original sources
PubMed2001

Recombinant chimeric OKT3 scFv IgM antibodies mediate immune suppression while reducing T cell activation in vitro.

OKT3, a mouse anti-human CD3 monoclonal antibody (mAb), is a potent immunosuppressive agent used in clinical transplantation to treat allograft rejection. Two major drawbacks of this therapy are the systemic release of several cytokines due to cross-linking mediated by the mAb between T cells and FcgammaR-bearing cells and the human anti-mouse antibody (HAMA) response. To overcome these side effects, three chimeric OKT3 single chain variable fragment (scFv) IgM antibodies, scOKT3-gamma DeltaIgM wt, scOKT3-gamma DeltaIgM C575S and scOKT3-gamma DeltaIgM VAEVD, were generated. They consist of the light and heavy variable binding domains of OKT3 mAb as well as the CH3 and CH4 domains of different human IgM variants linked with a human IgG3 hinge region to provide more flexibility and stability. Like the native IgM, scOKT3-gamma DeltaIgM antibodies are able to form polymeric structures, which lead to an increase in binding affinity and immunosuppressive potential compared with the parental OKT3 mAb. However, independently of their polymerization, all scOKT3-gamma DeltaIgM constructs do not induce any significant T cell proliferation or cytokine release (IL-2, TNF-alpha and IFN-gamma) in in vitro assays, while their CD3-modulating properties are retained. These results suggest that the use of scOKT3-gamma DeltaIgM antibodies may offer significant advantages over the OKT3 mAb in improving clinical immunosuppressive treatment.

Adult↗
PubMed2001

In vitro induction of a bladder cancer-specific T-cell response by mRNA-transfected dendritic cells.

PURPOSE: To design a tumor-specific immunotherapeutic strategy for treating tumors for which no specific antigens are described (such as bladder urothelial carcinoma), we attempted to activate tumor-specific T-cells by dendritic cells transfected with tumor-derived mRNA. METHODS: Dendritic cells were generated from a patient's peripheral blood and loaded with mRNA derived from the urothelial carcinoma tissue of the same patient. Autologous T-cells were incubated twice on these dendritic cells and tested for their ability to lyse tumor cells. RESULTS: Dendritic cells transfected with tumor-derived mRNA were able to activate T-cells that recognized autologous tumor cells. Cytotoxicity was around 26% for an effector:target ratio of 50:1. Tumor-infiltrating lymphocytes did not kill the autologous tumor cells in vitro, but after a single stimulation with the transfected dendritic cells, they induced tumor cell lysis of 35.7% at an effector:target ratio of 50:1. CONCLUSIONS: These results indicate that dendritic cells transfected with tumor mRNA containing messages for one or more tumor antigens could serve for the ex vivo activation of effector T-cells or directly as vaccines for a wide range of human neoplasias.

Aged↗
PubMed2001

Life disruption and generic complexity: a social linguistic analysis of narratives of cancer illness.

This paper draws on social linguistics to inquire into the meaning and function of complexity in illness narratives. According to social linguists, five different story-type genres occur in spoken English. These are illustrated and differentiated using examples drawn from 10 interviews with people who have undergone colectomy for colorectal cancer. In order to test a hypothesis that complexity in illness narratives is related to life disruption, the 10 accounts were ranked in terms of their generic complexity. Measures of life disruption were based on rankings furnished independently by two readers from different disciplines who were blind to the hypothesis being tested. These two rankings showed a high level of agreement (r(s) = 0.85, p<0.01). When the two life disruption rankings and the generic complexity ranking were compared, a high degree of concordance between the three rankings was observed (W = 0.91, p<0.01). No evidence was found of associations between generic complexity and gender, interviewer, surgical outcome in terms of stoma (p>0.05), age (p>0.7) nor time since diagnosis (p>0.1). We conclude that in this study, generic complexity was strongly and significantly related to life disruption. To explain the function of complexity in interaction, we characterise the illness narrative as a genre in its own right, and argue that illness narratives need to be considered both in terms of the work they do both on the listener and for the narrator. In the former case, complexity opens up a discursive space for the dynamic positioning of the interlocutor. In the latter case, we propose that complexity reflects the degree to which the process of re-ordering life by assigning meaning is occurring as the interaction unfolds. In both cases, complex narratives can thus be understood as "hard working" narratives.

Anecdotes as Topic↗
PubMed2001

Ethical relationships in paediatric emergency medicine: moving beyond the dyad.

Most areas of health-services research concentrate on a dyadic relationship between doctor and patient. In paediatric emergency medicine it may be necessary to focus on a more complicated relationship because the parents of the child play an important role in the delivery of medical services. This paper discusses the ethical principles in paediatric emergency medicine from the perspective of five disciplines: health economics, paediatrics, medical ethics, law and mental health. The general consensus is that the traditional dyadic model is inadequate and that a more complicated relationship is needed for the paediatric emergency setting, such as triadic, multiple-dyadic or polyadic. Such models allow the inclusion of the parents and possibly other family members, medical providers and community members. If the paediatric setting is considered in such a framework, it may be possible to deliver a more socially beneficial medical service.

Adolescent↗
PubMed2001

Attachment disruptions in seriously emotionally disturbed children: implications for treatment.

In this paper, we consider the effect of attachment disruptions on severe adjustment problems in school-age boys. Three groups of 9-11-year-old boys were sampled based on their degree of risk for adjustment difficulties: (1) boys in regular classrooms, (2) boys in regular classrooms who are at risk due to poverty, and (3) boys who have been placed in special education classrooms as a result of serious emotional disturbance (SED). Attachment disruptions were categorized according to the severity of major separations from the biological mother. SED children experienced significantly more severe disruptions of their relationships with their biological mothers and fathers than either the high-risk or comparison boys. Teachers' ratings indicated that both the high-risk and SED boys experienced more externalizing symptoms than comparison boys in regular classrooms. However, SED children were most clearly discriminated from their high-risk and comparison counterparts by higher levels of dissociative symptoms. Regression analyses indicated that children who had experienced maternal attachment disruptions were more likely to show dissociative symptomatology in the classroom setting and were more likely to develop dependent relationships with their teachers after risk group status, child age and family structure were controlled. Implications of these findings for the treatment of SED children are discussed.

Affective Symptoms↗
PubMed2001

Life-threatening cardiac failure in a healthy young female with Irukandji syndrome.

We present a case of a previously well 24-year-old female patient who developed severe and life-threatening Irukandji syndrome that required ventilation and inotropic support. This case provides further evidence that there are jellyfish other than the Irukandji jellyfish that can cause cardiac decompensation, and there is a suggestion that application of a pressure immobilization bandage may worsen the envenomation. We include our recommended treatment for the Irukandji syndrome.

Adult↗
PubMed2001

Jellyfish stings.

Explore the source record for details and available documents.

Analgesics↗
PubMed2000

Cure of Burkitt's lymphoma in severe combined immunodeficiency mice by T cells, tetravalent CD3 x CD19 tandem diabody, and CD28 costimulation.

To increase the valency, stability, and therapeutic potential of bispecific antibodies, we have constructed a tetravalent tandem diabody (Tandab) that is specific to both human CD3 (T-cell antigen) and CD19 (B-cell marker; S. M. Kipriyanov et al., J. Mol. Biol., 293: 41-56, 1999). It was generated by the functional dimerization of a single chain molecule that contained four antibody variable domains (V(H) and V(L)) in an orientation that prevented intramolecular pairing. Compared with a previously constructed heterodimeric CD3 x CD19 diabody, the Tandab exhibited a higher apparent affinity to both CD3+ and CD19+ cells and longer blood retention when injected into mice. Biodistribution studies in mice bearing Burkitt's lymphoma xenografts demonstrated specific accumulation of the radioiodinated Tandab in a tumor site with tumor-to-blood ratios of 1.5, 8.1, and 13.3 at 3, 18, and 24 h, respectively. Treatment of severe combined immunodeficiency mice bearing established Burkitt's lymphoma (5 mm in diameter) with human peripheral blood lymphocytes, Tandab, and anti-CD28 MAbs resulted in the complete elimination of tumors in all of the animals within 10 days. In contrast, mice receiving human peripheral blood lymphocytes in combination with either the diabody alone or the diabody plus anti-CD28 MAbs showed only partial tumor regression. These data demonstrate that the CD3 x CD19 Tandab may be a promising tool for the immunotherapy of human B-cell leukemias and lymphomas.

Animals↗
PubMed2000

Treatment of human B cell lymphoma xenografts with a CD3 x CD19 diabody and T cells.

The use of anti-CD3 x antitumor bispecific Abs is an attractive and highly specific approach in cancer therapy. Recombinant Ab technology now provides powerful tools to enhance the potency of such immunotherapeutic constructs. We designed a heterodimeric diabody specific for human CD19 on B cells and CD3epsilon chain of the TCR complex. After production in Escherichia coli and purification, we analyzed its affinity, stability, and pharmacokinetics, and tested its capacity to stimulate T cell proliferation and mediate in vitro lysis of CD19+ tumor cells. The effect of the diabody on tumor growth was investigated in an in vivo model using immunodeficient mice bearing a human B cell lymphoma. The CD3 x CD19 diabody specifically interacted with both CD3- and CD19-positive cells, was able to stimulate T cell proliferation in the presence of tumor cells, and induced the lysis of CD19+ cells in the presence of activated human PBL. The lytic potential of the diabody was enhanced in the presence of an anti-CD28 mAb. In vivo experiments indicated a higher stability and longer blood retention of diabodies compared with single chain Fv fragments. Treatment of immunodeficient mice bearing B lymphoma xenografts with the diabody and preactivated human PBL efficiently inhibited tumor growth. The survival time was further prolonged by including the anti-CD28 mAb. The CD3 x CD19 diabody is a powerful tool that should facilitate the immunotherapy of minimal residual disease in patients with B cell leukemias and malignant lymphomas.

Animals↗
PubMed2000

Construction and functional evaluation of a single-chain antibody fusion protein with fibrin targeting and thrombin inhibition after activation by factor Xa.

BACKGROUND: Recombinant technology was used to produce a new anticoagulant that is preferentially localized and active at the site of the clot. METHODS AND RESULTS: The variable regions of the heavy and light chains of a fibrin-specific antibody were amplified by polymerase chain reaction (PCR) with hybridoma cDNA. To obtain a functional single-chain antibody (scFv), a linker region consisting of (Gly(4)Ser)(3) was introduced by overlap PCR. After the scFv clones were ligated with DNA encoding the pIII protein of the M13 phage, high-affinity clones were selected by 10 rounds of panning on the Bbeta15-22 peptide of fibrin (beta-peptide). Hirudin was genetically fused to the C-terminus of the variable region of the light chain. To release the functionally essential N-terminus of hirudin at the site of a blood clot, a factor Xa recognition site was introduced between scFv(59D8) and hirudin. The fusion protein was characterized by its size on SDS-PAGE (36 kDa), by Western blotting, by its cleavage into a 29-kDa (single chain alone) and 7-kDa (hirudin) fragment, by its binding to beta-peptide, and by thrombin inhibition after Xa cleavage. Finally, the fusion protein inhibited appositional growth of whole blood clots in vitro more efficiently than native hirudin. CONCLUSIONS: A fusion protein was constructed that binds to a fibrin-specific epitope and inhibits thrombin after its activation by factor Xa. This recombinant anticoagulant effectively inhibits appositional clot growth in vitro. Its efficient and fast production at low cost should facilitate a large-scale evaluation to determine whether an effective localized antithrombin activity can be achieved without systemic bleeding complications.

Amino Acid Sequence↗
PubMed2000

Mice lacking the vascular endothelial growth factor-B gene (Vegfb) have smaller hearts, dysfunctional coronary vasculature, and impaired recovery from cardiac ischemia.

Vascular endothelial growth factor-B (VEGF-B) is closely related to VEGF-A, an effector of blood vessel growth during development and disease and a strong candidate for angiogenic therapies. To further study the in vivo function of VEGF-B, we have generated Vegfb knockout mice (Vegfb(-/-)). Unlike Vegfa knockout mice, which die during embryogenesis, Vegfb(-/-) mice are healthy and fertile. Despite appearing overtly normal, Vegfb(-/-) hearts are reduced in size and display vascular dysfunction after coronary occlusion and impaired recovery from experimentally induced myocardial ischemia. These findings reveal a role for VEGF-B in the development or function of coronary vasculature and suggest potential clinical use in therapeutic angiogenesis.

Aging↗
PubMed2000

Ethonomics: the ethics of the unaffordable.

The most familiar basis for medical ethics since the 1950s has been principle-based ethics. The 4 basic principles are known as the "Georgetown mantra" of beneficence, nonmaleficence, respect for autonomy, and justice. These principles have served us well since their enunciation in the wake of the activities of the Nazi doctors in the concentration and extermination camps of World War II. In the past 15 years, however, they have begun to serve less well. In the era of resource constraints, however, the clinical relationship has become more complex. It now involves many more stakeholders, who control funds, make policy, and effectively ration services. Lawyers are also involved in important ways. All these people take part with varying directness in the processes of consultation and treatment. The consulting room has become a crowded office. For these reasons, the old ethics will no longer serve us. We need a new ethics that recognizes the involvement of the new stakeholders, and recognizes that resource constraints influence clinical practice.

Cost Control↗
PubMed2000

Fine mapping of the neurally expressed gene SOX14 to human 3q23, relative to three congenital diseases.

Members of the Sox gene family encode transcription factors that have diverse and important functions during development. We have recently described the cloning of chick and mouse Sox14 and the expression of these genes in a population of ventral interneurons in the embryonic spinal cord. We report here the cloning and sequencing of the human orthologue of Sox14. Human SOX14 shows remarkable sequence conservation compared with orthologues from other vertebrate species and probably mirrors the expression of these genes in the developing brain and spinal cord. Using radiation hybrid mapping and fluorescence in situ hybridisation, we have localised SOX14 close to the sequence tagged site D3S1576 on human chromosome 3q23. Three congenital disorders have been localised to this region: blepharophimosis-ptosis-epicanthus inversus syndrome (BPES), Charcot-Marie-Tooth neuropathy type IIB (CMT2B) and Mobius syndrome type 2 (MBS2). We have found that SOX14 is unlikely to be involved in any of these disorders because of the position of SOX14 proximal to a BPES breakpoint and the lack of SOX14 coding region alterations in BPES, CMT2B and MBS2 patients.

Amino Acid Sequence↗
PubMed2000

Of mice and men: hybridoma and recombinant antibodies.

Thousands of mouse monoclonal antibodies have been produced from hybridomas over the past 25 years. The same technique can now be used to clone human antibodies from transgenic mice. Full-length antibodies and recombinant fragments engineered for various diagnostic and therapeutic applications can be obtained in reasonably large amounts after expression in mammalian cells, milk and plants.

Animals↗
PubMed2000

Expression of the vertebrate Slit gene family and their putative receptors, the Robo genes, in the developing murine kidney.

The slit (sli) gene, encoding a secreted glycoprotein, has been demonstrated to play a vital role in axonal guidance in Drosophila melanogaster by acting as a signalling ligand for the robo receptor (Rothberg, J.M., Jacobs, J.R., Goodman, C.S., Artavanis-Tsakonas, S., 1990. slit: an extracellular protein necessary for development of midline glia and commissural axon pathways contains both EGF and LRR domains. Genes Dev. 4, 2169-2187; Kidd, T., Bland, K.S., Goodman, C. S., 1999. Slit is the midline repellent for the robo receptor in Drosophila. Cell 96, 785-794). Multiple homologs of both sli and robo have been identified in vertebrates and are thought to play similar roles to their fly counterparts in neural development (Brose, K., Bland, K.S., Wang, K.H., Arnott, D., Henzel, W., Goodman, C.S., Tessier-Lavigne, M., Kidd, T., 1999. Slit proteins bind Robo receptors and have an evolutionarily conserved role in repulsive axon guidance. Cell 96, 795-806). Slit2 has been shown to bind Robo1, mediating both neuronal and axonal guidance in the developing central nervous system (CNS), (Brose et al., 1999; Hu, H., 1999. Chemorepulsion of neuronal migration by Slit2 in the developing mammalian forebrain. Neuron 23, 703-711). Importantly, both gene families display distinct expression patterns outside the CNS (Holmes, G.P., Negus, K., Burridge, L., Raman, S., Algar, E., Yamada, T., Little, M.H., 1998. Distinct but overlapping expression patterns of two vertebrate slit homologs implies functional roles in CNS development and organogenesis. Mech. Dev. 79, 57-72; Yuan, W., Zhou, L., Chen, J.H., Wu, J.Y., Rao, Y., Ornitz, D.M., 1999. The mouse SLIT family: secreted ligands for ROBO expressed in patterns that suggest a role in morphogenesis and axon guidance. Dev. Biol. 212, 290-306). Using in situ hybridization on metanephric explant cultures and urogenital tract sections, the expression patterns of Slit1, 2, 3 and Robo1 and 2 were investigated during murine metanephric development. Slit1 was expressed in the metanephric mesenchyme (MM) surrounding the invading ureteric tree (UT). Slit2 was expressed at the tips of the UT and both Slit2 and Slit3 were expressed at the far proximal end of the comma shaped and S-shaped bodies. Expression of Robo1 was initially diffuse throughout the MM, then upregulated in the pretubular aggregates, and maintained at the distal end of the comma and S-shaped bodies. Robo2 was detected in the induced MM surrounding the arborizing UT tips and later in the proximal end of the S-shaped bodies. Coincident expression of Robo1 with Slit1 in the metanephric mesenchyme and Robo2, Slit2 and Slit3 in the far proximal end of the S-shaped bodies was observed during metanephric development.

Animals↗