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1.
Int Nurs Rev ; 59(2): 187-93, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22591089

RESUMO

AIM: The purpose of this study is to identify central challenges to be addressed in cultural safety education. BACKGROUND: In recent years, the idea of cultural safety has received increased attention as a way of dealing with diversity in the nursing profession, especially in divided societies. The idea of cultural safety goes beyond recognizing and appreciating difference, to an attempt to grappling with deeper issues like inequality, conflict and histories of oppression. METHODS: The paper is based on formative evaluation, using action research, of an academic nursing programme in Israel, involving Jewish and Arab students. Part of this research dealt with the integration of cultural safety education into the curriculum. FINDINGS: The study revealed four challenges in cultural safety education: making it safe for minorities to present their culture to the majority group ('the ambassador's dilemma'), dealing with tendency of groups to deny the existence of conflict ('the one big happy family fantasy'), making dynamics of oppression discussable ('the oppressed and the oppressor') and creating conditions in which people can freely choose their individual and group identities ('the threat of identity'). CONCLUSION: Cultural safety education may be experienced as unsafe for many participants. Better understanding of the challenges of cultural safety education is necessary for making it more effective.


Assuntos
Árabes , Competência Cultural/educação , Diversidade Cultural , Educação em Enfermagem , Judeus , Segurança , Conflito Psicológico , Currículo , Pesquisa sobre Serviços de Saúde , Humanos , Israel , Estudos de Casos Organizacionais , Identificação Social , Estudantes/psicologia
2.
Int Nurs Rev ; 56(3): 299-305, 2009 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-19702802

RESUMO

AIM: The aim of this paper is twofold: to conceptualize tensions related to the academization of nursing, and to analyse a case study, describing how such tensions were dealt with in the process of establishing a new nursing department. BACKGROUND: This paper represents the first stage of a case study of the transformation of a hospital-based nursing school into an academic programme, carried out as a joint venture between a local hospital school and a college in northern Israel. METHODS: This paper is based on action research. The participants were 19 members of the new academic faculty and 3 members of an action research center. FINDINGS: The three inter-related tensions surfaced in the research process are: (1) the status of nursing and nurses, (2) the role of research and critical thinking in nursing education and practice, and (3) the characteristics of students, who should enroll in and graduate from nursing programmes, or in other words, the character of the 'ideal nurse'. CONCLUSIONS: An action research process enables new teams to put tensions on the table so they can be openly addressed through ongoing reflection, inquiry, learning, evaluation and redesign.


Assuntos
Docentes de Enfermagem/organização & administração , Inovação Organizacional , Escolas de Enfermagem/organização & administração , Atitude do Pessoal de Saúde , Mobilidade Ocupacional , Competência Clínica , Educação em Enfermagem/tendências , Humanos , Israel , Papel do Profissional de Enfermagem , Pesquisa em Educação em Enfermagem , Estudos de Casos Organizacionais , Critérios de Admissão Escolar , Percepção Social
3.
Ultrasound Obstet Gynecol ; 30(5): 783-5, 2007 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-17899575

RESUMO

An uncommon cause of delayed postpartum hemorrhage is a pseudoaneurysm of the uterine artery. Pelvic arterial pseudoaneurysm is generally treated by laparotomy and hemostatic sutures or by uterine artery embolization. We describe two cases of late postpartum hemorrhage following Cesarean section, attributed to pelvic arterial pseudoaneurysm, that were successfully treated by direct thrombin injection under ultrasound guidance. Percutaneous or transvaginal ultrasound-guided direct thrombin injection is a simple procedure that does not require any sophisticated surgical or radiological equipment.


Assuntos
Falso Aneurisma/diagnóstico por imagem , Cesárea/efeitos adversos , Hemostáticos/uso terapêutico , Hemorragia Pós-Parto/tratamento farmacológico , Trombina/uso terapêutico , Útero/irrigação sanguínea , Adulto , Falso Aneurisma/tratamento farmacológico , Feminino , Humanos , Injeções Intra-Arteriais , Hemorragia Pós-Parto/etiologia , Gravidez , Resultado do Tratamento , Ultrassonografia
4.
Surg Endosc ; 15(4): 364-7, 2001 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-11395816

RESUMO

BACKGROUND: Now that the laparoscopic treatment of symptomatic liver cystic disease has proven feasible and safe, it is gaining wide acceptance. However, due to diagnostic pitfalls and a relatively high recurrence rate, further improvements and refinement of the procedure are still needed. We have evaluated the contribution of laparoscopic ultrasound in the diagnosis and management of patients with symptomatic liver cysts. METHODS: Twelve patients with single or multiple cysts of the liver and two patients with polycystic liver disease were managed laparoscopically. Laparoscopic ultrasound served as an integral part of the procedure in all patients. RESULTS: Patients underwent either complete cyst excision (two cases) or resection of the extrahepatic cystic component (eight cases). Additionally, in two patients, deep cysts not demonstrated by preoperative imaging studies were detected and treated with a combination of laparoscopy and laparoscopic ultrasound. In one patient with a cystobiliary fistula, conversion to an open cystjejunostomy was necessary. Patients with polycystic liver disease underwent a combination of excision and unroofing of both superficial and deeper cysts using laparoscopic contact ultrasound throughout the procedure. Laparoscopic ultrasonography was found to have a significant impact on the operative strategy in five patients (36%) with multiple cysts or polycystic disease. The postoperative course was uneventful in all cases. Thirteen patients remained asymptomatic throughout the follow-up period of 30 months; one patient with polycystic liver disease developed recurrent symptoms after 5 months and was treated with left hepatectomy. CONCLUSION: Additional use of laparoscopic ultrasound enables the detection, differentiation, and treatment of deep, nonvisualized cystic lesions (two patients, 16.6%) and validation of the adequacy of the laparoscopic procedure.


Assuntos
Cistos/diagnóstico por imagem , Cistos/cirurgia , Laparoscopia/métodos , Hepatopatias/diagnóstico por imagem , Hepatopatias/cirurgia , Terapia por Ultrassom/métodos , Adulto , Idoso , Feminino , Humanos , Fígado/diagnóstico por imagem , Fígado/cirurgia , Masculino , Pessoa de Meia-Idade , Resultado do Tratamento , Ultrassonografia Doppler/métodos
5.
Eur J Radiol ; 28(3): 222-5, 1998 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-9881256

RESUMO

The aim of the study is to prove, retrospectively, that it is unlikely that the computerized tomography (CT) diagnosis of subarachnoid haemorrhage (SH) accompanies the CT diagnosis of generalized brain edema. A total of 100 comatose patients underwent CT of the brain. Of this number, 42 underwent an enhanced CT scan. In 26 patients, lumbar puncture was also performed. A control group of ten patients diagnosed with headache and having a normal CT scan underwent NECT and ECT. Measurements of the white and gray matter density in Hounsfield units (HU) were performed in all 110 cases, including the controls. The brain tissue density and the difference between the densities of the white and gray matter were lower in the cases with brain edema than in the controls. The data values were statistically significant. Small cerebral ventricles, sulci and cisterns and small differences between white and gray matter measurements were observed in the CT scans of the brain edema cases. All 100 patients had CT diagnosis of brain edema and SH. There was no bloody or xanthochromic CSF in any of the 26 lumbar punctures performed. In the enhanced CT scans, there was poor or no filling of the lateral sinuses. The compression of the lateral sinuses by the edematous brain tissue most probably results in their stenosis or obstruction due to disturbed brain venous drainage which can mimic CT findings of SH.


Assuntos
Edema Encefálico/diagnóstico por imagem , Hemorragia Subaracnóidea/diagnóstico por imagem , Tomografia Computadorizada por Raios X , Adolescente , Adulto , Idoso , Encéfalo/diagnóstico por imagem , Estudos de Casos e Controles , Criança , Pré-Escolar , Meios de Contraste , Feminino , Humanos , Lactente , Ácido Iotalâmico/análogos & derivados , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos
6.
Crit Care Med ; 23(10): 1745-55, 1995 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-7587242

RESUMO

OBJECTIVES: To test a model for the assessment of critical care technology on closed loop infusion control, a technology that is in its early stages of development and testing on human subjects. DATA SOURCES: A computer-assisted search of the English language literature and reviews of the gathered data by experts in the field of closed loop infusion control systems. STUDY SELECTION: Studies relating to closed loop infusion control that addressed one or more of the questions contained in our technology assessment template were analyzed. Study design was not a factor in article selection. However, the lack of well-designed clinical outcome studies was an important factor in determining our conclusions. DATA EXTRACTION: A focus person summarized the data from the selected studies that related to each of the assessment questions. The preliminary data summary developed by the focus person was further analyzed and refined by the task force. Experts in closed loop systems were then added to the group to review the summary provided by the task force. These experts' comments were considered by the task force and this final consensus report was developed. DATA SYNTHESIS: Closed loop system control is a technological concept that may be applicable to several aspects of critical care practice. This is a technology in the early stages of evolution and much more research and data are needed before its introduction into usual clinical practice. Furthermore, each specific application and each device for each application (e.g., nitroprusside infusion, ventilator adjustment), although based on the same technological concept, are sufficiently different in terms of hardware and computer algorithms to require independent validation studies. CONCLUSIONS: Closed loop infusion systems may have a role in critical care practice. However, for most applications, further development is required to move this technology from the innovation phase to the point where it can be evaluated so that its role in critical car practice can be defined. Each application of closed loop infusion systems must be independently validated by appropriately designed research studies. Users should be provided with the clinical parameters driving each closed loop system so that they can ensure that it agrees with their opinion of acceptable medical practice. Clinical researchers and leaders in industry should collaborate to perform the scientifically valid, outcome-based research that is necessary to evaluate the effect of this new technology. The original model we developed for technology assessment required the addition of several more questions to produce a complete analysis of an emerging technology. An emerging technology should be systematically assessed (using a model such as the model developed by the Society of Critical Care Medicine), before its introduction into clinical practice in order to provide a focus for human outcome validation trials and to minimize the possibility of widespread use of an unproven technology.


Assuntos
Cuidados Críticos , Bombas de Infusão , Avaliação da Tecnologia Biomédica/métodos , Algoritmos , Computadores , Desenho de Equipamento , Humanos , Modelos Teóricos
7.
J Virol ; 69(10): 6389-99, 1995 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-7666540

RESUMO

To investigate E7-dependent biochemical changes which are involved in cellular transformation, we analyzed the influence of human papillomavirus type 16 (HPV-16) E7 on the expression of cell cycle regulatory proteins. Expression of E7 in established rodent fibroblasts (NIH 3T3), which was shown to be sufficient for transformation of these cells, leads to constitutive expression of the cyclin E and cyclin A genes in the absence of external growth factors. Surprisingly, expression of the cyclin D1 gene, which encodes a major regulator of G1 progression, is unaltered in E7-transformed cells. In transient transfection experiments, the cyclin A gene promoter is activated by E7 via an E2F binding site. In 14/2 cells, which were used as a model system to analyze the role of HPV-16 E7 in the transformation of primary cells, we observed rapid E7-dependent activation of cyclin E gene expression, which can be uncoupled from activation of the cyclin A gene, since the latter requires additional protein synthesis. E7-driven induction of cyclin E and cyclin A gene expression was accompanied by an increase in the associated kinase activities. Two domains of the E7 oncoprotein, which are designated cd1 and cd2, are essential for transformation of rodent fibroblasts. It is shown here that growth factor-independent expression of the cyclin E gene requires cd2 but not cd1, while activation of cyclin A gene expression requires cd1 function in addition to that of cd2. These data suggest that cyclin A gene expression is controlled by two distinct negative signals, one of which also restricts expression of the cyclin E gene. The ability of E7 to separately override each of these inhibitory signals, via cd1 and cd2, cosegregates with its ability to fully transform rodent fibroblasts. Unlike serum growth factors, E7 induces S-phase entry without activating cyclin D1 gene expression, in keeping with the finding that cyclin D1 function is not required in cells transformed by DNA tumor viruses.


Assuntos
Transformação Celular Neoplásica , Quinases Ciclina-Dependentes/metabolismo , Ciclinas/biossíntese , Regulação Viral da Expressão Gênica , Proteínas Oncogênicas Virais/metabolismo , Papillomaviridae/metabolismo , Células 3T3 , Animais , Western Blotting , Ciclo Celular/efeitos dos fármacos , Divisão Celular/efeitos dos fármacos , Linhagem Celular , Dexametasona/farmacologia , Cinética , Camundongos , Proteínas Oncogênicas Virais/biossíntese , Papillomaviridae/genética , Proteínas E7 de Papillomavirus , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/metabolismo , Fatores de Tempo , Transfecção
8.
Gene ; 158(2): 291-4, 1995 Jun 09.
Artigo em Inglês | MEDLINE | ID: mdl-7607556

RESUMO

We have analyzed and compared the 5' promoter region, the intron structure and the exon-intron flanking sequences in the rat and human prohibitin-encoding genes (PHB). Comparative analysis of a 350-nt region immediately 5' to and including the first exon identifies eight highly conserved regions, four of which correspond to binding sites for known transcriptional control proteins (CCAAT box, 'SV40' site and two Sp1 sites). The promoter lacks a TATA box. Four transcription start points (tsp) clustered within a 35-bp region were identified by rapid amplification of cDNA ends (RACE). The exon-intron boundaries in rat and human are highly conserved, with identical positioning of splice junctions. PCR analysis with conserved exon primers was used to detect length variation between rat and human PHB, and length differences were observed in all of the introns.


Assuntos
Proteínas/genética , Proteínas Repressoras , Animais , Sequência de Bases , Evolução Biológica , Divisão Celular/genética , Sequência Conservada , Éxons/genética , Genes Reguladores/genética , Humanos , Íntrons/genética , Dados de Sequência Molecular , Proibitinas , Regiões Promotoras Genéticas/genética , Ratos , Análise de Sequência de DNA , Homologia de Sequência do Ácido Nucleico
9.
J Cell Physiol ; 157(2): 289-95, 1993 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-8227162

RESUMO

Prohibitin, a novel intracellular antiproliferative protein, blocks entry into the S phase of the cell division cycle when its mRNA is microinjected into normal fibroblasts or HeLa cells. To learn more about the interaction between prohibitin and the cell cycle, we studied the effect of microinjecting prohibitin mRNA at different points during the transition from G0 to S phase and analyzed prohibitin mRNA and protein levels in different parts of the cell cycle. The antiproliferative activity of microinjected prohibitin mRNA is high in G0/G1 and falls as cells approach S phase. Prohibitin mRNA and protein levels are high in G1, fall with S phase, rise again in G2, and fall in M. Together, these findings suggest that endogenous prohibitin contributes to the control of the G1 to S transition in cycling cells in a complex manner, which involves both a transcriptional and posttranslational mechanism.


Assuntos
Fibroblastos/citologia , Proteínas/genética , RNA Mensageiro/análise , Proteínas Repressoras , Animais , Western Blotting , Ciclo Celular/fisiologia , Divisão Celular/fisiologia , Células Cultivadas , Fibroblastos/química , Fibroblastos/metabolismo , Humanos , Masculino , Microinjeções , Proibitinas , Proteínas/análise , Proteínas/metabolismo , RNA Mensageiro/administração & dosagem , RNA Mensageiro/genética , Ratos , Fase de Repouso do Ciclo Celular , Fase S
10.
Crit Care Clin ; 9(3): 491-500, 1993 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-8353787

RESUMO

The competition for scarce finances for equipment/technology purchases can be won with careful preparation and documentation. Planning and implementing effective negotiation strategies can lower the cost of new technology acquisitions.


Assuntos
Unidades de Terapia Intensiva/organização & administração , Administração de Materiais no Hospital/organização & administração , Avaliação da Tecnologia Biomédica/organização & administração , Gastos de Capital , Tomada de Decisões Gerenciais , Humanos , Equipes de Administração Institucional , Unidades de Terapia Intensiva/economia , Serviço Hospitalar de Compras , Estados Unidos
11.
Bull Cancer ; 79(9): 883-91, 1992.
Artigo em Francês | MEDLINE | ID: mdl-1486224

RESUMO

Forty patients with intermediate stage (T2 > 3 cm-T3, N0-N1) operable breast cancer received neoadjuvant chemotherapy by MCF (mitoxantrone, cyclophosphamide, 5-fluorouracil). Four cycles were administered at 3-week intervals. The obvious hematological toxicity (64% of grade III for the leucocytes and up to 34% of grade IV for the granulocytes) was rapidly reversible and did not hinder completion of the treatment. Ten patients showed a complete remission and a tumor volume regression of more than 50% was observed in 12 other patients. Tumor shrinkage allowed breast-saving surgery in 50% of the cases. A complete sterilisation of the surgical specimen was found in only two of the 40 patients and a few persisting neoplastic cells were found in ten other cases. A positive response at the level of the axillary lymph nodes was also obtained in more than 50% of the cases. In 25 of the 36 cases examined, the primary chemotherapy induced cellular lesions (fibrosis, necrosis) at the tumor level. A feasibility study was undertaken in order to determine quantitatively several biochemical parameters (steroid hormone receptors, cathepsin D, c-erbB-2 oncoprotein) in very small tumor samples obtained by Tru-Cut before any treatment and in surgical specimens. In the future, these micromethods will be used systematically with the aim of estimating the value of these potential prognostic factors for therapeutic follow-up of the patients.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias da Mama/terapia , Adulto , Idoso , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/patologia , Neoplasias da Mama/cirurgia , Terapia Combinada , Ciclofosfamida/uso terapêutico , Feminino , Fluoruracila/uso terapêutico , França , Humanos , Pessoa de Meia-Idade , Mitoxantrona/uso terapêutico , Estadiamento de Neoplasias , Indução de Remissão
12.
Genomics ; 11(1): 228-30, 1991 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-1684951

RESUMO

Prohibition is a recently identified antiproliferative protein whose exact role in the cell is under investigation. To determine the human chromosomal location of the prohibition gene (PHB) and whether this site corresponds to that of any suspected tumor suppressor gene, we have analyzed DNA from three sources by hybridization analysis: mouse--human hybrid cell lines, hybrid cell lines containing portions of human chromosomes, and human metaphase chromosomes in situ. All three techniques confirm a location in the region 17q21-q22, a region genetically linked to early-onset human breast cancer. Further analysis will be required to establish the significance of this relationship; Southern hybridizations show a polymorphic EcoRI site that may be useful for this purpose.


Assuntos
Cromossomos Humanos Par 17 , Polimorfismo de Fragmento de Restrição , Proteínas/genética , Proteínas Repressoras , Southern Blotting , Bandeamento Cromossômico , Mapeamento Cromossômico , Feminino , Humanos , Masculino , Linhagem , Proibitinas
13.
Mol Cell Biol ; 11(3): 1372-81, 1991 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-1996099

RESUMO

Genes that act inside the cell to negatively regulate proliferation are of great interest because of their implications for such processes as development and cancer, but these genes have been difficult to clone. This report details the cloning and analysis of cDNA for prohibitin, a novel mammalian antiproliferative protein. Microinjection of synthetic prohibitin mRNA blocks entry into S phase in both normal fibroblasts and HeLa cells. Microinjection of an antisense oligonucleotide stimulates entry into S phase. By sequence comparison, the prohibitin gene appears to be the mammalian analog of Cc, a Drosophila gene that is vital for normal development.


Assuntos
Ciclo Celular , Proteínas/genética , Proteínas Repressoras , Sequência de Aminoácidos , Animais , Sequência de Bases , Northern Blotting , Clonagem Molecular , DNA/biossíntese , DNA/genética , Genes , Células HeLa , Humanos , Fígado/fisiologia , Microinjeções , Dados de Sequência Molecular , Proibitinas , Biossíntese de Proteínas , RNA Mensageiro/genética , Ratos , Homologia de Sequência do Ácido Nucleico , Transcrição Gênica
14.
Exp Cell Res ; 189(2): 222-6, 1990 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-2164482

RESUMO

The incidence of most cancers increases with aging. To examine whether this increased risk might be related to a higher susceptibility of older cells to neoplastic transformation, we transfected rat fibroblasts aged in vivo and in vitro with origin-defective SV40 DNA and measured the number of transformed foci. Substantial increases in the number of transformed foci were observed in cells from adult rats when compared with those of cells from embryos or weanlings. Much higher numbers of foci were also obtained at late passage, when 68% or more of the in vitro lifespan had been completed, while no foci were produced from cells at early or middle passage. To control for changes with aging in uptake, integration, or expression of exogenous DNA, parallel cultures were transfected with a G418 resistance gene. The number of G418-resistant colonies did not increase with aging and, in fact, decreased in late passage embryonic cell cultures. Therefore, increased susceptibility to SV40 transformation appears to be a feature of development and in vitro aging in rat cells.


Assuntos
Transformação Celular Neoplásica , Vírus 40 dos Símios/genética , Pele/crescimento & desenvolvimento , Envelhecimento , Animais , Animais Recém-Nascidos , Linhagem Celular , Células Cultivadas , DNA Viral/isolamento & purificação , Suscetibilidade a Doenças , Embrião de Mamíferos , Fibroblastos/citologia , Plasmídeos , Ratos , Ratos Endogâmicos , Pele/citologia
15.
Mech Ageing Dev ; 52(1): 27-43, 1990 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-2314127

RESUMO

To identify genes whose expression changes as a function of aging, we screened mouse cDNA libraries with cDNAs from mice of different ages. Specifically, whole-mouse cDNA libraries were constructed in lambda gt10 using poly(A) RNA from young (3 month) and old (27 month) C57BL/6J inbred mice and these lambda plaques were hybridized with radioactive cDNAs made from pooled poly(A) RNA from animals 3 or 33 months of age. Five clones were isolated that showed an aging-related pattern of expression and four of these were identified by computerized sequence matching to the GenBank database: MUP2 (a major urinary protein); Q10 of the MHC locus; a cytoskeletal actin gene; and creatine kinase. One gene whose expression increases with aging and is most abundant in spleen remains unidentified. All five cDNAs showed 4-fold to 17-fold changes with aging in their steady-state mRNA levels in at least one tissue.


Assuntos
Envelhecimento/fisiologia , DNA/fisiologia , Expressão Gênica/fisiologia , Hibridização Genética/fisiologia , Envelhecimento/genética , Animais , DNA/isolamento & purificação , Hibridização Genética/genética , Técnicas In Vitro , Masculino , Camundongos , Camundongos Endogâmicos C57BL
16.
Eur J Immunol ; 16(9): 1093-7, 1986 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-2428626

RESUMO

The effect of a protease inhibitor, leupeptin, on the presentation of hen egg lysozyme (HEL) to cloned T cells was investigated. We found that leupeptin-sensitive thiol proteases are apparently less involved when HEL is presented by the I-Ad molecule, than when it is presented by the I-Ed molecule. This selectivity was more of a function of the antigen than that of the Ia molecule because presentation of denatured or fragmented HEL was not sensitive to leupeptin whereas antigen presentation to a number of I-A-restricted T cell clones specific to other antigens was sensitive to leupeptin. These data demonstrate that the particular combination of major histocompatibility complex/nominal antigen recognized by a certain T cell clone may require processing of the antigen molecule through a certain group of proteases and that other combinations are independent of that particular processing pathway. Furthermore, there is a preference for a certain type of processing depending on the Ia molecule involved.


Assuntos
Células Apresentadoras de Antígenos/metabolismo , Antígenos , Antígenos de Histocompatibilidade Classe II/fisiologia , Complexo Principal de Histocompatibilidade , Peptídeo Hidrolases/fisiologia , Animais , Células Apresentadoras de Antígenos/efeitos dos fármacos , Células Clonais , Epitopos/análise , Antígenos H-2/imunologia , Leupeptinas/farmacologia , Camundongos , Camundongos Endogâmicos , Muramidase/imunologia , Muramidase/metabolismo , Linfócitos T/metabolismo
17.
Eur J Immunol ; 11(5): 382-7, 1981 May.
Artigo em Inglês | MEDLINE | ID: mdl-6167448

RESUMO

Competitive antigen binding experiments were performed with purified T and B cells of C3H.SW (H-2b) mice. As antigen, (T,G)-A--L [poly-L(Tyr,Glu)-poly-DL-ALa-poly-L Lys] was used, both in an Ia-containing form, released by adherent cells (IAC-Puri and Lonai, Eur. J. Immunol. 1980. 10:273), and in regular solution. It was found that regular (T,G)-A-L did not compete with the binding of 125I-labeled-IAC-(T,G)-A--L even at a 10(4)-fold excess, whereas IAC-(T,G)-A--L inhibited binding at 10-fold excess. The specificity of (T,G)-A--L binding to high-responder T and B cells was compared by using related branched synthetic copolymers as competitors. B cells cross-reacted with (T,G)-A--L, (H,G)-A--L, (G)-A--L and (T,G)-Pro--L. In contrast, antigen binding C3H.SW T cells cross-reacted only with (T,G)-A--L and (Phe, G)-A--L to both of which they are Ir gene-controlled high responders. Evidence for the Ir gene control of IAC-binding T cells was obtained by showing that high X low responder F1 hybrid T cells preferentally bind IAC-(T,G)-A--L processed by processor cells deriving from the high-responder parental strain. These data are interpreted to suggest that T cells have high affinity for antigen plus self Ia complexes, whereas they have a much lower, if any, affinity for free antigen. It also follows from the results that the structure of the complex ligand may have a role in defining the specificity, H-2 restriction and Ir gene control of T cells.


Assuntos
Epitopos , Antígenos de Histocompatibilidade Classe II , Receptores de Antígenos de Linfócitos T , Animais , Antígenos , Ligação Competitiva , Relação Dose-Resposta Imunológica , Camundongos , Camundongos Endogâmicos C3H , Peptídeos/imunologia , Receptores de Antígenos de Linfócitos B , Solubilidade
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