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1.
Br J Cancer ; 126(1): 134-143, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34611308

RESUMO

BACKGROUND: We wished to examine treatment and outcome patterns in older diffuse large B-cell lymphoma (DLBCL) patients, with a focus on the effect of route-to-diagnosis to outcome. METHODS: Data were extracted from Public Health England's National Cancer Registration and Analysis Service between 2013 and 2015 included route-to-diagnosis, disease characteristics and survival for 9186 patients ≥65 years. Systemic Anti-Cancer Therapy data identified front-line regimens, cycles and doses. RESULTS: Route-to-diagnosis were emergency (34%), NHS urgent cancer pathway (rapid haemato-oncologist review <2 weeks), (29%) and standard GP referral (25%). The most common regimen was R-CHOP (n = 4392). 313 patients received R-miniCHOP (7% of R-CHOP). For all patients, 3-year overall survival (OS) for 65-79 years was 57% and for ≥80 years was 32%. Three-year OS for R-CHOP-treated patients diagnosed via emergency presentation was 54% (adjusted hazard ratio (HR) 1.63, p < 0.01) and 75% (adjusted HR 0.81, p < 0.01) on the NHS urgent cancer pathway (reference HR:1.00: GP referrals). 3-year OS was 54% for both R-miniCHOP and R-CHOP in ≥80 years. CONCLUSIONS: Our comprehensive population analysis is the first to show that the NHS urgent cancer pathway is associated with a superior survival after adjusting for multiple confounders. Equivalent survival for R-CHOP and R-mini-CHOP was demonstrated in those ≥80 years.


Assuntos
Assistência Ambulatorial/métodos , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Bases de Dados Factuais/estatística & dados numéricos , Linfoma Difuso de Grandes Células B/tratamento farmacológico , Padrões de Prática Médica/estatística & dados numéricos , Idoso , Idoso de 80 Anos ou mais , Ciclofosfamida/uso terapêutico , Doxorrubicina/uso terapêutico , Inglaterra/epidemiologia , Humanos , Linfoma Difuso de Grandes Células B/epidemiologia , Linfoma Difuso de Grandes Células B/patologia , Prednisona/uso terapêutico , Estudos Retrospectivos , Rituximab/uso terapêutico , Taxa de Sobrevida , Vincristina/uso terapêutico
2.
J Intern Med ; 285(6): 681-692, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30811713

RESUMO

BACKGROUND: The increasing incidence of diffuse large B-cell lymphoma (DLBCL) in ageing populations places a significant burden on healthcare systems. Co-morbidity, frailty, and reduced organ and physiological reserve contribute to treatment-related complications. The optimal dose intensity of R-CHOP to optimize outcome across different ages with variable frailty and comorbidity burden is unclear. OBJECTIVES AND METHODS: We examined the influence of intended (IDI) and relative (RDI) dose intensity of the combination of cyclophosphamide and doxorubicin, age and comorbidity on outcomes for DLBCL patients ≥70 years in a representative, consecutive cohort across eight UK centres (2009-2018). We determined predictors of survival using multivariable Cox regression, and predictors of recurrence before death using competing risks regression. RESULTS: Porgression-free survival (PFS) and overall survival (OS) were significantly inferior in patients ≥80 vs. 70-79 years (P < 0.001). In contrast, 2-year cumulative relapse incidence, when accounting for non-relapse mortality as a competing risk, was no different between 70-79 vs. ≥80 years (P = 0.27) or comorbidity status (CIRS-G: 0-6 vs. >6) (P = 0.27). In 70-79 years, patients with an IDI ≥80% had a significantly improved PFS and OS (P < 0.001) compared to IDI < 80%. Conversely, in patients ≥80 years, there was no difference in PFS (P = 0.88) or OS (P = 0.75) according to IDI <80% vs. ≥80%. On multivariable analysis, when comparing by age, there was a significantly higher cumulative relapse rate for patients aged 70-79 years with an IDI <80% (vs. >80%) (P = 0.04) but not for patients ≥80 years comparing IDI (P = 0.32). CONCLUSION: 'R-mini-CHOP' provides adequate lymphoma-specific disease control and represents a reasonable treatment option in elderly patients ≥80 years aiming for cure.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Linfoma Difuso de Grandes Células B/tratamento farmacológico , Distribuição por Idade , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Estudos de Coortes , Comorbidade , Ciclofosfamida/administração & dosagem , Doxorrubicina/administração & dosagem , Feminino , Humanos , Incidência , Linfoma Difuso de Grandes Células B/epidemiologia , Masculino , Prednisona/administração & dosagem , Recidiva , Estudos Retrospectivos , Rituximab/administração & dosagem , Resultado do Tratamento , Vincristina/administração & dosagem
3.
Epidemiol Infect ; 147: e187, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-31063111

RESUMO

Although researchers have described numerous risk factors for salmonellosis and for infection with specific common serotypes, the drivers of Salmonella serotype diversity among human populations remain poorly understood. In this retrospective observational study, we partition records of serotyped non-typhoidal Salmonella isolates from human clinical specimens reported to CDC national surveillance by demographic, geographic and seasonal characteristics and adapt sample-based rarefaction methods from the field of community ecology to study how Salmonella serotype diversity varied within and among these populations in the USA during 1996-2016. We observed substantially higher serotype richness in children <2 years old than in older children and adults and steadily increasing richness with age among older adults. Whereas seasonal and regional variation in serotype diversity was highest among infants and young children, variation by specimen source was highest in adults. Our findings suggest that the risk for infection from uncommon serotypes is associated with host and environmental factors, particularly among infants, young children and older adults. These populations may have a higher proportion of illness acquired through environmental transmission pathways than published source attribution models estimate.


Assuntos
Infecções por Salmonella/epidemiologia , Salmonella/genética , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Infecções por Salmonella/microbiologia , Estações do Ano , Sorogrupo , Estados Unidos/epidemiologia , Adulto Jovem
4.
Ann Oncol ; 29(3): 544-562, 2018 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-29194473

RESUMO

The European Society for Medical Oncology (ESMO) consensus conference on mature B cell lymphomas and chronic lymphocytic leukaemia (CLL) was held on 20 June 2015 in Lugano, Switzerland, and included a multidisciplinary panel of 25 leading experts. The aim of the conference was to develop recommendations on critical subjects difficult to consider in detail in the ESMO Clinical Practice Guidelines. The following areas were identified: (1) the elderly patient, (2) prognostic factors suitable for clinical use, and (3) the 'ultra-high-risk' group. Before the conference, the expert panel was divided into three working groups; each group focused on one of these areas in order to address clinically-relevant questions relating to that topic. All relevant scientific literature, as identified by the experts, was reviewed in advance. During the consensus conference, each working group developed recommendations to address each of the four questions assigned to their group. These recommendations were presented to the entire panel and a consensus was reached. This consensus, which was further developed in continuous post-meeting discussions, formed the basis of three manuscripts, each covering one of the three key areas identified. This manuscript presents the consensus recommendations regarding the clinical management of elderly patients diagnosed with malignant lymphoma. Four clinically-relevant topics identified by the panel were: 1) how to define patient fitness, 2) assessing quality of life, 3) diagnostic work-up and 4) clinical management of elderly patients with lymphoma. Each of these key topics is addressed in the context of five different lymphoma entities, namely: CLL, follicular lymphoma, mantle cell lymphoma, peripheral T-cell lymphoma and diffuse large B-cell lymphoma. Results, including a summary of evidence supporting each recommendation, are detailed in this manuscript.


Assuntos
Leucemia Linfocítica Crônica de Células B/diagnóstico , Leucemia Linfocítica Crônica de Células B/terapia , Linfoma de Células B/diagnóstico , Linfoma de Células B/terapia , Idoso de 80 Anos ou mais , Animais , Feminino , Humanos , Masculino
5.
Artigo em Inglês | MEDLINE | ID: mdl-27132979

RESUMO

Oncology services do not routinely assess broader needs of older people with cancer. This study evaluates a comprehensive geriatric assessment and comorbidity screening questionnaire (CGA-GOLD) covering evidence-based domains and quality of life (EORTC-QLQ-C30). Patients aged 65+ attending oncology services were recruited into (1) Observational cohort (completed CGA-GOLD, received standard oncology care), (2) Intervention cohort (responses categorised 'low-risk', 'high-risk', 'possible need' by geriatricians). N = 417 observational patients (1002 invited by post, 418 consented, age 73.9 ± 5.4) completed CGA-GOLD in 11.7 ± 7.9 min, 86.3% required no assistance, 3.1% overall missing responses. Multiple problems reported: hypertension (18.1%), diabetes (16.9%), dyspnoea on flat surfaces (27.6%), polypharmacy (46%), difficulty walking (14.9%), fatigue (40.5%), living alone (30.9%), social isolation (11.2%), recent functional dependence (27.8%), urinary incontinence (21.4%), falls (13.3%). 237/239 intervention patients completed CGA-GOLD and consecutive subsets examined. The doctor and nurse specialist independently identified same need level in 87.3% (high inter-rater reliability kappa = 0.80), taking 1-2 min per questionnaire. Need level remained unchanged following hospital notes review against responses in 90% (75/83). 'Possible need' patients were telephoned with change in 29% (16/55) to low-risk and none to high-risk, confirming high need was not being missed. CGA-GOLD screening questionnaire was acceptable to older patients, feasibly administered in NHS cancer services, described comorbidities, CGA and QOL needs, and reliably identified higher risk patients requiring further input for optimal cancer treatment.


Assuntos
Avaliação Geriátrica/métodos , Avaliação das Necessidades , Neoplasias/terapia , Atividades Cotidianas , Idoso , Idoso de 80 Anos ou mais , Estudos de Coortes , Comorbidade , Diabetes Mellitus/diagnóstico , Diabetes Mellitus/epidemiologia , Dispneia/diagnóstico , Dispneia/epidemiologia , Fadiga/diagnóstico , Fadiga/epidemiologia , Feminino , Humanos , Hipertensão/diagnóstico , Hipertensão/epidemiologia , Londres/epidemiologia , Masculino , Programas de Rastreamento/métodos , Limitação da Mobilidade , Neoplasias/epidemiologia , Polimedicação , Características de Residência , Medição de Risco , Isolamento Social , Inquéritos e Questionários , Incontinência Urinária/diagnóstico , Incontinência Urinária/epidemiologia
6.
Rev Panam Salud Publica ; 39(4): 194-9, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-27657184

RESUMO

Objective To assess cervical cancer prevalence and associated mortality in Grenada, West Indies during 2000-2010. Methods Records of visits to hospital and clinical facilities were obtained from the histopathology laboratory of the Grenada General Hospital. Records were de-identified and electronically compiled. Cervical cancer prevalence was assessed via cross-sectional analysis of this secondary data. Of a total 12 012 records, 2 527 were selected for analysis using sampling without replacement. Cases were matched to corresponding patient data from death registries, where possible, and used to calculate associated mortality rates. Results The observed prevalence of cervical cancer was 52.4 per 100 000 women (ages 15 and above). The highest rates of cervical cancer occurred in the 35-44 age group, with the second highest among 45-64-year-olds. A total of 65 deaths were attributable to cervical cancer during 2000-2010, more than 50% of which were among women > 65 years old. The observed mortality rate was 16.7 per 100 000, almost twice the rate estimated by WHO for the region. Conclusions This study demonstrates the need for a comprehensive cervical cancer-screening program in Grenada. Results should contribute to informing future studies on how to appropriately generate and execute public health policy for education, screening, prevention, and control of cervical cancer in Grenada.


Assuntos
Neoplasias do Colo do Útero/epidemiologia , Adolescente , Adulto , Distribuição por Idade , Idoso , Estudos Transversais , Feminino , Granada/epidemiologia , Humanos , Pessoa de Meia-Idade , Prevalência , Sistema de Registros , Neoplasias do Colo do Útero/mortalidade
7.
Br J Cancer ; 112(9): 1435-44, 2015 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-25871332

RESUMO

BACKGROUND: Although comorbidities are identified in routine oncology practice, intervention plans for the coexisting needs of older people receiving chemotherapy are rarely made. This study evaluates the impact of geriatrician-delivered comprehensive geriatric assessment (CGA) interventions on chemotherapy toxicity and tolerance for older people with cancer. METHODS: Comparative study of two cohorts of older patients (aged 70+ years) undergoing chemotherapy in a London Hospital. The observational control group (N=70, October 2010-July 2012) received standard oncology care. The intervention group (N=65, September 2011-February 2013) underwent risk stratification using a patient-completed screening questionnaire and high-risk patients received CGA. Impact of CGA interventions on chemotherapy tolerance outcomes and grade 3+ toxicity rate were evaluated. Outcomes were adjusted for age, comorbidity, metastatic disease and initial dose reductions. RESULTS: Intervention participants undergoing CGA received mean of 6.2±2.6 (range 0-15) CGA intervention plans each. They were more likely to complete cancer treatment as planned (odds ratio (OR) 4.14 (95% CI: 1.50-11.42), P=0.006) and fewer required treatment modifications (OR 0.34 (95% CI: 0.16-0.73), P=0.006). Overall grade 3+ toxicity rate was 43.8% in the intervention group and 52.9% in the control (P=0.292). CONCLUSIONS: Geriatrician-led CGA interventions were associated with improved chemotherapy tolerance. Standard oncology care should shift towards modifying coexisting conditions to optimise chemotherapy outcomes for older people.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos/epidemiologia , Avaliação Geriátrica , Neoplasias/tratamento farmacológico , Neoplasias/reabilitação , Idoso , Idoso de 80 Anos ou mais , Estudos de Casos e Controles , Comorbidade , Tolerância a Medicamentos , Feminino , Seguimentos , Humanos , Londres/epidemiologia , Masculino , Metástase Neoplásica , Planejamento de Assistência ao Paciente , Prognóstico , Estudos Prospectivos
8.
Br J Cancer ; 111(12): 2224-8, 2014 Dec 09.
Artigo em Inglês | MEDLINE | ID: mdl-25268369

RESUMO

BACKGROUND: Significant toxicity in chemotherapy trials is usually defined as grade ⩾3. In clinical practice, however, multiple lower grade toxicities are often considered meaningful. The purpose of this observational cohort study was to identify which level of toxicity triggers treatment modification and early discontinuation of chemotherapy in older people. METHODS: Patients aged 65+ were recruited in a central London hospital. A total of 108 patients were recruited at the start of new chemotherapy treatment between October 2010 and July 2012. RESULTS: Mean age was 72.1 ± 5 years, median 72 and range 65-86 years. Of the patients, 50.9% (55) were male with gastrointestinal (49), gynaecological (18), lung (15) and other cancers (26). Chemotherapy was palliative in 59.3% (64/108), curative/ neoadjuvant/adjuvant in the others. Mean number of cycles completed was 4.2 ± 3. Treatment modifications due to toxicity occurred in 60 (55.6%) patients, 35% (21/60) of whom had no greater than grade 2 toxicity. Early treatment discontinuation because of toxicity occurred in 23 patients (21.3%), 39.1% (9/23) of whom had no greater than grade 2 toxicity. CONCLUSIONS: Many older patients did not complete treatment as planned. Treatment was modified/discontinued even for one or two low-grade toxicities. Further work is required to clarify whether low-grade toxicity has a greater clinical impact in older people, or whether clinicians have a lower threshold for modifying/discontinuing treatment in older people.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Neoplasias/tratamento farmacológico , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Feminino , Humanos , Masculino
9.
J Evol Biol ; 27(3): 616-27, 2014 03.
Artigo em Inglês | MEDLINE | ID: mdl-26227899

RESUMO

Admixture, the mixing of historically isolated gene pools, can have immediate consequences for the genetic architecture of fitness traits. Admixture may be especially important for newly colonized populations, such as during range expansion and species invasions, by generating heterozygosity that can boost fitness through heterosis. Despite widespread evidence for admixture during species invasions, few studies have examined the demographic history leading to admixture, how admixture affects the heterozygosity and fitness of invasive genotypes, and whether such fitness effects are maintained through time. We address these questions using the invasive plant Silene vulgaris, which shows evidence of admixture in both its native Europe and in North America where it has invaded. Using multilocus genotype data in conjunction with approximate Bayesian computation analysis of demographic history, we showed that admixture during the invasion of North America was independent from and much younger than admixture in the native range of Europe. We tested for fitness consequences of admixture in each range and detected a significant positive heterozygosity-fitness correlation (HFC) in North America; in contrast, no HFC was present in Europe. The lack of HFC in Europe may reflect the longer time since admixture in the native range, dissipating associations between heterozygosity at markers and fitness loci. Our results support a key short-term role for admixture during the early stages of invasion by generating HFCs that carry populations past the threat of extinction from inbreeding and demographic stochasticity.


Assuntos
Heterozigoto , Espécies Introduzidas , Teorema de Bayes
10.
Heredity (Edinb) ; 112(2): 99-104, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24002238

RESUMO

Non-random association of alleles in the nucleus and cytoplasmic organelles, or cyto-nuclear linkage disequilibrium (LD), is both an important component of a number of evolutionary processes and a statistical indicator of others. The evolutionary significance of cyto-nuclear LD will depend on both its magnitude and how stable those associations are through time. Here, we use a longitudinal population genetic data set to explore the magnitude and temporal dynamics of cyto-nuclear disequilibria through time. We genotyped 135 and 170 individuals from 16 and 17 patches of the plant species Silene latifolia in Southwestern VA, sampled in 1993 and 2008, respectively. Individuals were genotyped at 14 highly polymorphic microsatellite markers and a single-nucleotide polymorphism (SNP) in the mitochondrial gene, atp1. Normalized LD (D') between nuclear and cytoplasmic loci varied considerably depending on which nuclear locus was considered (ranging from 0.005-0.632). Four of the 14 cyto-nuclear associations showed a statistically significant shift over approximately seven generations. However, the overall magnitude of this disequilibrium was largely stable over time. The observed origin and stability of cyto-nuclear LD is most likely caused by the slow admixture between anciently diverged lineages within the species' newly invaded range, and the local spatial structure and metapopulation dynamics that are known to structure genetic variation in this system.


Assuntos
Núcleo Celular/genética , Citoplasma/genética , Genoma de Planta , Desequilíbrio de Ligação , Silene/genética , Genes Mitocondriais , Heterogeneidade Genética , Genética Populacional , Polimorfismo de Nucleotídeo Único , Locos de Características Quantitativas
11.
J Clin Microbiol ; 50(12): 4098-9, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23015665

RESUMO

According to the Kauffmann-White scheme, 39 pairs of serovars in Salmonella serogroup C2 differ only by the minor antigen O:6(1). We characterized strains from 10 serovars representing five Salmonella serogroup C2 pairs. All strains demonstrated variable expression of O:6(1). These results indicate that these pairs are not distinct serovars.


Assuntos
Antígenos O/análise , Salmonella/classificação , Salmonella/isolamento & purificação , Sorotipagem , Expressão Gênica , Variação Genética , Humanos
13.
World Neurosurg ; 162: e41-e48, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35108647

RESUMO

BACKGROUND: Residents in multiple surgical specialties are trained to perform peripheral nerve surgery (PNS), but the extent of exposure to this field varies among specialties. This study evaluates trends in volume of PNS performed during residency for neurologic surgery trainees compared to those in plastic and orthopedic surgery between 2009 and 2019. METHODS: We queried ACGME for neurologic, plastic, and orthopedic surgery resident case-logs and compared mean number of PNS between graduating residents of each specialty using a one-way analysis of variance test. Linear regression was utilized to determine trends within and across the specialties over the study period. RESULTS: Neurosurgery residents (24.76 ± 3.41) performed significantly fewer PNS than their counterparts in orthopedic (54.56 ± 6.85) and plastic surgery (71.96 ± 12.20), P < 0.001. Residents in neurologic surgery reported over 1.5-fold as many cases as their ACGME-required minimum, in contrast to plastic (2.5-fold) and orthopedic (5-fold). Plastics residents (3.46 cases/year) demonstrated the greatest longitudinal increase in PNS, followed by neurosurgery residents (0.81 cases/year). PNS accounted for a mean of 5.81% of neurosurgery resident cases, 4.20% of plastic surgery resident cases, and 2.98% of orthopedic surgery resident cases (P < 0.001). CONCLUSIONS: Neurosurgery residents exceeded the required minimum number of PNS and were increasingly more exposed to PNS. However, compared with their counterparts in orthopedic and plastic surgery, neurosurgery residents performed significantly fewer cases. Exposure for neurosurgery residents remains unchanged over the study period while plastic surgery residents experienced an increase in case volume. The deficiency in exposure for neurosurgical residents must be addressed to harness interest and proficiency in PNS.


Assuntos
Cirurgia Geral , Internato e Residência , Neurocirurgia , Procedimentos Ortopédicos , Ortopedia , Cirurgia Plástica , Educação de Pós-Graduação em Medicina , Humanos , Neurocirurgia/educação , Ortopedia/educação , Nervos Periféricos
14.
Nat Med ; 5(1): 56-63, 1999 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-9883840

RESUMO

Hemophilia B is a severe X-linked bleeding diathesis caused by the absence of functional blood coagulation factor IX, and is an excellent candidate for treatment of a genetic disease by gene therapy. Using an adeno-associated viral vector, we demonstrate sustained expression (>17 months) of factor IX in a large-animal model at levels that would have a therapeutic effect in humans (up to 70 ng/ml, adequate to achieve phenotypic correction, in an animal injected with 8.5x10(12) vector particles/kg). The five hemophilia B dogs treated showed stable, vector dose-dependent partial correction of the whole blood clotting time and, at higher doses, of the activated partial thromboplastin time. In contrast to other viral gene delivery systems, this minimally invasive procedure, consisting of a series of percutaneous intramuscular injections at a single timepoint, was not associated with local or systemic toxicity. Efficient gene transfer to muscle was shown by immunofluorescence staining and DNA analysis of biopsied tissue. Immune responses against factor IX were either absent or transient. These data provide strong support for the feasibility of the approach for therapy of human subjects.


Assuntos
Dependovirus , Fator IX/genética , Técnicas de Transferência de Genes , Vetores Genéticos , Hemofilia B/terapia , Animais , DNA Viral/análise , Dependovirus/genética , Modelos Animais de Doenças , Cães , Fator IX/imunologia , Expressão Gênica , Hemofilia B/imunologia , Humanos , Injeções Intramusculares , Masculino , Fatores de Tempo , Células Tumorais Cultivadas
15.
J Exp Med ; 188(1): 205-10, 1998 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-9653097

RESUMO

Ligation of cytotoxic T lymphocyte antigen 4 (CTLA4) appears to inhibit T cell responses. Four mechanisms have been proposed to explain the inhibitory activity of CTLA4: competition for B7-1 and B7-2 binding by CD28; sequestration of signaling molecules away from CD28 via endocytosis; delivery of a signal that antagonizes a CD28 signal; and delivery of a signal that antagonizes a T cell receptor (TCR) signal. As three of these potential mechanisms involve functional antagonism of CD28, an experimental model was designed to determine whether CTLA4 could inhibit T cell function in the absence of CD28. TCR transgenic/recombinase activating gene 2-deficient/CD28-wild-type or CD28-deficient mice were generated and immunized with an antigen-expressing tumor. Primed T cells from both types of mice produced cytokines and proliferated in response to stimulator cells lacking B7 expression. However, whereas the response of CD28+/+ T cells was augmented by costimulation with B7-1, the response of the CD28-/- T cells was strongly inhibited. This inhibition was reversed by monoclonal antibody against B7-1 or CTLA4. Thus, CTLA4 can potently inhibit T cell activation in the absence of CD28, indicating that antagonism of a TCR-mediated signal is sufficient to explain the inhibitory effect of CTLA4.


Assuntos
Antígenos de Diferenciação/metabolismo , Antígeno B7-1/imunologia , Antígenos CD28/imunologia , Imunoconjugados , Linfócitos T/metabolismo , Abatacepte , Animais , Antígenos CD , Antígenos CD28/genética , Antígeno CTLA-4 , Divisão Celular/fisiologia , Linhagem Celular , Citocinas/antagonistas & inibidores , Citocinas/metabolismo , Proteínas de Ligação a DNA/genética , Camundongos , Camundongos Transgênicos , Receptores de Antígenos de Linfócitos T/antagonistas & inibidores , Transdução de Sinais/imunologia
16.
J Exp Med ; 178(1): 73-85, 1993 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-8315396

RESUMO

Although reported examples of endogenous antigen (Ag) presentation by major histocompatibility complex (MHC) class II molecules have increased, the mechanisms governing this process remain poorly defined. In this communication, we describe an experimental system designed to examine the mechanisms governing class II presentation of internal Ag. Our target peptide is processed from a transmembrane protein constitutively expressed by a variety of nucleated cells (MHC class I, H-2Ld), is naturally displayed by MHC class II molecules in vivo, and is recognized by a class II-restricted, CD4+ T cell hybridoma. Our results indicate that presentation of the Ld target Ag is independent of its plasma membrane expression, may not involve endosomal proteolysis, and thus may be distinct from the classically defined class II presentation pathway. In addition, the observations that Ld presentation does not require a functional TAP-1 complex, is not blocked by invariant chain, and cannot utilize cytoplasmic forms of H-2Ld, suggest that a classical class I pathway is not involved in this presentation event. Finally, our data suggest that different cofactors participate in MHC class II presentation of exogenous and endogenous Ag, and that disparate Ag presenting cells, such as B, T, and pancreatic islet cells, may differentially express these two class II pathways of Ag presentation.


Assuntos
Células Apresentadoras de Antígenos/fisiologia , Antígenos de Diferenciação de Linfócitos B , Antígenos de Histocompatibilidade Classe II/imunologia , Antígenos de Histocompatibilidade Classe I/imunologia , Animais , Células Clonais , Antígenos H-2/análise , Antígenos de Histocompatibilidade Classe II/fisiologia , Hibridomas , Ilhotas Pancreáticas/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Linfócitos T/imunologia
17.
J Exp Med ; 186(2): 229-38, 1997 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-9221752

RESUMO

One enigma in tumor immunology is why animals bearing malignant grafts can reject normal grafts that express the same nonself-antigen. An explanation for this phenomenon could be that different T cell clones react to the normal graft and the malignant cells, respectively, and only the tumor-reactive clonotypes may be affected by the growing tumor. To test this hypothesis, we used a T cell receptor transgenic mouse in which essentially all CD8(+) T cells are specific for a closely related set of self-peptides presented on the MHC class I molecule Ld. We find that the tumor expressed Ld in the T cell receptor transgenic mice but grew, while the Ld-positive skin was rejected. Thus, despite an abundance of antigen-specific T cells, the malignant tissue grew while normal tissue expressing the same epitopes was rejected. Therefore, systemic T cell exhaustion or anergy was not responsible for the growth of the antigenic cancer cells. Expression of costimulatory molecules on the tumor cells after transfection and preimmunization by full-thickness skin grafts was required for rejection of a subsequent tumor challenge, but there was no detectable effect of active immunization once the tumor was established. Thus, the failure of established tumors to attract and activate tumor-specific T cells at the tumor site may be a major obstacle for preventive or therapeutic vaccination against antigenic cancer.


Assuntos
Antígenos de Histocompatibilidade Classe I/fisiologia , Tolerância Imunológica , Neoplasias Experimentais/imunologia , Receptores de Antígenos de Linfócitos T/fisiologia , Linfócitos T/imunologia , Animais , Rejeição de Enxerto , Imunização , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C3H , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos DBA , Camundongos Transgênicos , Transplante de Pele/imunologia , Transfecção
18.
Science ; 243(4894 Pt 1): 1059-62, 1989 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-2646710

RESUMO

Facultative intracellular pathogens pose an important health problem because they circumvent a primary defense mechanism of the host: killing and degradation by professional phagocytic cells. A gene of the intracellular pathogen Salmonella typhimurium that is required for virulence and intracellular survival was identified and shown to have a role in resistance to defensins and possibly to other microbicidal mechanisms of the phagocyte. This gene may prove to be a regulatory element in the expression of virulence functions.


Assuntos
Proteínas Sanguíneas/fisiologia , Genes Bacterianos , Fagócitos/fisiologia , Salmonella typhimurium/genética , Animais , Grânulos Citoplasmáticos/análise , DNA Bacteriano/genética , Defensinas , Humanos , Macrófagos/análise , Macrófagos/fisiologia , Camundongos , Camundongos Endogâmicos BALB C , Mutação , Neutrófilos/análise , Hibridização de Ácido Nucleico , Plasmídeos , Coelhos , Salmonella typhimurium/patogenicidade
19.
Science ; 271(5253): 1276-8, 1996 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-8638108

RESUMO

T cell anergy is a state of functional unresponsiveness characterized by the inability to produce interleukin-2 (IL-2) upon T cell receptor stimulation. The mitogen-activated protein kinases ERK-1 and ERK-2 and the guanosine triphosphate-binding protein p21ras were found to remain unactivated upon stimulation of anergic murine T helper cell 1 clones. The inability to activate the Ras pathway did not result from a defect in association among Shc, Grb-2, and murine Son of Sevenless, nor from a defect in their tyrosine phosphorylation. This block in Ras activation may lead to defective transactivation at activator protein 1 sites in anergic cells and may enable T cells to shut down IL-2 production selectively during anergy.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal , Anergia Clonal , Proteínas Quinases Ativadas por Mitógeno , Proteínas Proto-Oncogênicas p21(ras)/metabolismo , Transdução de Sinais , Células Th1/imunologia , Animais , Antígenos CD4/imunologia , Proteínas Quinases Dependentes de Cálcio-Calmodulina/metabolismo , Células Clonais , Proteína Adaptadora GRB2 , Fatores de Troca do Nucleotídeo Guanina , Guanosina Trifosfato/metabolismo , Interleucina-2/biossíntese , Ionomicina/farmacologia , Ativação Linfocitária , Camundongos , Proteína Quinase 1 Ativada por Mitógeno , Proteína Quinase 3 Ativada por Mitógeno , Proteínas Tirosina Quinases/metabolismo , Proteínas/metabolismo , Receptores de Antígenos de Linfócitos T/imunologia , Acetato de Tetradecanoilforbol/farmacologia , Células Th1/metabolismo , Fatores ras de Troca de Nucleotídeo Guanina
20.
Science ; 152(3728): 1504-6, 1966 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-17788029

RESUMO

Six out of eight minor chemical elements, determined by spectroscopic and neutron-activation techniques, were found to be critical in computing a probability that a given copper artifact was derived from one of three types of copper ore: native metal, oxidized ore, reduced ore. Two elements, gold and tin, were apparently alloyed deliberately in many artifacts from both the Old World and the New World.

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