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1.
South Med J ; 116(9): 745-749, 2023 09.
Artículo en Inglés | MEDLINE | ID: mdl-37657781

RESUMEN

OBJECTIVES: The coronavirus disease 2019 (COVID-19) pandemic disrupted how educational conferences were delivered, leaving programs to choose between in-person and virtual morning report formats. The objective of our study was to describe morning reports during the COVID-19 pandemic, including the use of virtual formats, attendance, leadership, and content. METHODS: A prospective observational study of morning reports was conducted at 13 Internal Medicine residency programs between September 1, 2020 and March 30, 2021, including a follow-up survey of current morning report format in January 2023. RESULTS: In total, 257 reports were observed; 74% used virtual formats, including single hospital, multiple hospital, and a hybrid format with both in-person and virtual participants. Compared with in-person reports, virtual reports had more participants, with increased numbers of learners (median 21 vs 7; P < 0.001) and attendings (median 4 vs 2; P < 0.001), and they were more likely to involve medical students (83% vs 40%; P < 0.001), interns (99% vs 53%; P < 0.001), and program directors (68% vs 32%; P < 0.001). Attendings were less likely to lead virtual reports (3% vs 28%, P < 0.001). Virtual reports also were more likely to be case based (88% vs 69%; P < 0.001) and to use digital presentation slides (91% vs 36%; P < 0.001). There was a marked increase in the number of slides (median 20 vs 0; P < 0.001). As of January 2023, all 13 programs had returned to in-person reports, with only 1 program offering an option to participate virtually. CONCLUSIONS: During the COVID-19 pandemic, virtual morning report formats predominated. Compared with traditional in-person reports, virtual report increased attendance, favored resident leadership, and approached a similar range of patient diagnoses with a greater number of case-based presentations and slides. In spite of these characteristics, all programs returned to an in-person format for morning report as pandemic restrictions waned.


Asunto(s)
COVID-19 , Rondas de Enseñanza , Humanos , COVID-19/epidemiología , Pandemias , Escolaridad , Hospitales
2.
BMC Med Educ ; 23(1): 84, 2023 Feb 02.
Artículo en Inglés | MEDLINE | ID: mdl-36732763

RESUMEN

BACKGROUND: Morning report is a core educational activity in internal medicine resident education. Attending physicians regularly participate in morning report and influence the learning environment, though no previous study has described the contribution of attending physicians to this conference. This study aims to describe attending comments at internal medicine morning reports. METHODS: We conducted a prospective, observational study of morning reports conducted at 13 internal medicine residency programs between September 1, 2020, and March 30, 2021. Each attending comment was described including its duration, whether the comment was teaching or non-teaching, teaching topic, and field of practice of the commenter. We also recorded morning report-related variables including number of learners, report format, program director participation, and whether report was scripted (facilitator has advance knowledge of the case). A regression model was developed to describe variables associated with the number of attending comments per report. RESULTS: There were 2,344 attending comments during 250 conferences. The median number of attendings present was 3 (IQR, 2-5). The number of comments per report ranged across different sites from 3.9 to 16.8 with a mean of 9.4 comments/report (SD, 7.4). 66% of comments were shorter than one minute in duration and 73% were categorized as teaching by observers. The most common subjects of teaching comments were differential diagnosis, management, and testing. Report duration, number of general internists, unscripted reports, and in-person format were associated with significantly increased number of attending comments. CONCLUSIONS: Attending comments in morning report were generally brief, focused on clinical teaching, and covered a wide range of topics. There were substantial differences between programs in terms of the number of comments and their duration which likely affects the local learning environment. Morning report stakeholders that are interested in increasing attending involvement in morning report should consider employing in-person and unscripted reports. Additional studies are needed to explore best practice models of attending participation in morning report.


Asunto(s)
Internado y Residencia , Rondas de Enseñanza , Humanos , Estudios Prospectivos , Competencia Clínica , Medicina Interna/educación
3.
J Gen Intern Med ; 37(6): 1422-1428, 2022 05.
Artículo en Inglés | MEDLINE | ID: mdl-34173198

RESUMEN

IMPORTANCE: The COVID-19 pandemic disrupted graduate medical education, compelling training programs to abruptly transition to virtual educational formats despite minimal experience or proficiency. We surveyed residents from a national sample of internal medicine (IM) residency programs to describe their experiences with the transition to virtual morning report (MR), a highly valued core educational conference. OBJECTIVE: Assess resident views about virtual MR content and teaching strategies during the COVID-19 pandemic. DESIGN: Anonymous, web-based survey. PARTICIPANTS: Residents from 14 academically affiliated IM residency programs. MAIN MEASURES: The 25-item survey on virtual MR included questions on demographics; frequency and reason for attending; opinions on who should attend and teach; how the virtual format affects the learning environment; how virtual MR compares to in-person MR with regard to participation, engagement, and overall education; and whether virtual MR should continue after in-person conferences can safely resume. The survey included a combination of Likert-style, multiple option, and open-ended questions. RESULTS: Six hundred fifteen residents (35%) completed the survey, with a balanced sample of interns (39%), second-year (31%), and third-year (30%) residents. When comparing their overall assessment of in-person and virtual MR formats, 42% of residents preferred in-person, 18% preferred virtual, and 40% felt they were equivalent. Most respondents endorsed better peer-engagement, camaraderie, and group participation with in-person MR. Chat boxes, video participation, audience response systems, and smart boards/tablets enhanced respondents' educational experience during virtual MR. Most respondents (72%) felt that the option of virtual MR should continue when it is safe to resume in-person conferences. CONCLUSIONS: Virtual MR was a valued alternative to traditional in-person MR during the COVID-19 pandemic. Residents feel that the virtual platform offers unique educational benefits independent of and in conjunction with in-person conferences. Residents support the integration of a virtual platform into the delivery of MR in the future.


Asunto(s)
COVID-19 , Internado y Residencia , Rondas de Enseñanza , COVID-19/epidemiología , Humanos , Pandemias , Encuestas y Cuestionarios
4.
Angew Chem Int Ed Engl ; 61(38): e202202137, 2022 Sep 19.
Artículo en Inglés | MEDLINE | ID: mdl-35274798

RESUMEN

This work describes the design and synthesis of a π-conjugated telluro[3,2-ß][1]-tellurophene-based synthon that, embodying pyridyl and haloaryl chalcogen-bonding acceptors, self-assembles into nanoribbons through chalcogen bonds. The ribbons π-stack in a multi-layered architecture both in single crystals and thin films. Theoretical studies of the electronic states of chalcogen-bonded material showed the presence of a local charge density between Te and N atoms. OTFT-based charge transport measurements showed hole-transport properties for this material. Its integration as a p-type semiconductor in multi-layered CuI -based light-emitting electrochemical cells (LECs) led to a 10-fold increase in stability (38 h vs. 3 h) compared to single-layered devices. Finally, using the reference tellurotellurophene congener bearing a C-H group instead of the pyridyl N atom, a herringbone solid-state assembly is formed without charge transport features, resulting in LECs with poor stabilities (<1 h).

5.
6.
J Med Ethics ; 39(1): 55-8, 2013 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-23065491

RESUMEN

BACKGROUND: Studies have shown that medical students and residents believe that their ethics preparation has been inadequate for handling ethical conflicts. The objective of this study was to determine the self-perceived comfort level of medical students and residents in confronting clinical ethics issues. METHODS: Clinical medical students and residents at the University of Maryland School of Medicine completed a web-based survey between September 2009 and February 2010. The survey consisted of a demographic section, questions regarding the respondents' sense of comfort in handling a variety of clinical ethics issues, and a set of knowledge-type questions in ethics. RESULTS: Survey respondents included 129 medical students (response rate of 40.7%) and 207 residents (response rate of 52.7%). There were only a few clinical ethics issues with which more than 70% of the respondents felt comfortable in addressing. Only a slight majority (60.8%) felt prepared, in general, to handle clinical situations involving ethics issues, and only 44.1% and 53.2% agreed that medical school and residency training, respectively, helped prepare them to handle such issues. Prior ethics training was not associated with these responses, but there was an association between the level of training (medical students vs residents) and the comfort level with many of the clinical ethics issues. CONCLUSIONS: Medical educators should include ethics educational methods within the context of real-time exposure to medical ethics dilemmas experienced by physicians-in-training.


Asunto(s)
Discusiones Bioéticas , Ética Médica , Internado y Residencia/estadística & datos numéricos , Percepción Social , Estudiantes de Medicina/estadística & datos numéricos , Adulto , Factores de Confusión Epidemiológicos , Estudios Transversales , Curriculum/normas , Femenino , Humanos , Internado y Residencia/ética , Internado y Residencia/métodos , Internado y Residencia/normas , Masculino , Maryland , Relaciones Médico-Paciente/ética , Estudiantes de Medicina/psicología , Encuestas y Cuestionarios
7.
Fed Pract ; 40(2): 50-55, 2023 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-37222999

RESUMEN

Background: The US Department of Veterans Affairs (VA) is the largest educator of health professions trainees in the country, but the roles and responsibilities of the modern clinician educator are increasingly challenging and complex. Most VA academic hospitalists with access to professional and faculty development receive it through academic affiliates. Many VA hospitalists lack this option, and teaching within the VA is unique given its specific health system, clinical environments, and patient population. Observations: Teaching the Teacher is a facilitation-based educational series for inpatient hospitalists at VA medical centers that is tailored to self-reported needs and provides faculty development through the lens of VA medicine. The transition from in-person to synchronous virtual programming allowed for wider dissemination of the program, and to date, 10 VA hospitalist sections across the country have participated in the series. Conclusions: VA clinicians want and deserve dedicated training to optimize their confidence and skills in their roles as health professions educators. Teaching the Teacher is a pilot faculty development program that has met success based on its goal of meeting the specific needs of VA clinician educators in hospital medicine. It has the potential to serve as a model for clinical educator onboarding and to allow for the rapid spread of best teaching practices among clinical educators.

8.
Int J Cancer ; 127(5): 1124-30, 2010 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-20027629

RESUMEN

Immunotherapy of colorectal carcinoma (CRC) has great promise as the presence of T lymphocytes in CRC tissues in situ is correlated with reduced recurrence and increased survival. Thus, identification of the antigens recognized by T cells of CRC patients may permit development of vaccines with potential benefit for these patients. Using expression cloning, we identified the antigen, nucleophosmin (Npm), recognized by an HLA-A1 restricted cytotoxic T lymphocyte (CTL) line derived from the peripheral blood mononuclear cells (PBMC) of a rectal cancer patient. A decamer peptide derived from the Npm sequence sensitized peptide-pulsed HLA-A1 positive cells to lysis by the CTL line. The peptide also induced proliferative and cytotoxic T lymphocytes in the PBMC of 4 of 6 CRC patients, which lysed HLA-A1 positive peptide-pulsed target cells and CRC cells endogenously expressing Npm. Overexpression of Npm by tumors of various histological types, recognition of the antigen by T cells derived from different CRC patients and association of the antigen with poor prognostic outcome make it a promising target for immunotherapeutic intervention in cancer patients.


Asunto(s)
Antígeno HLA-A1/inmunología , Proteínas Nucleares/inmunología , Fragmentos de Péptidos/farmacología , Neoplasias del Recto/inmunología , Linfocitos T Citotóxicos/inmunología , Presentación de Antígeno , Antígenos de Neoplasias/inmunología , Neoplasias de la Mama/inmunología , Neoplasias de la Mama/patología , Células Cultivadas , Neoplasias Colorrectales/inmunología , Neoplasias Colorrectales/patología , Femenino , Humanos , Inmunoterapia , Activación de Linfocitos , Melanoma/inmunología , Melanoma/patología , Nucleofosmina , Fragmentos de Péptidos/inmunología , Neoplasias del Recto/patología
9.
Cancer Res ; 67(8): 3555-9, 2007 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-17440064

RESUMEN

Antigens recognized by T helper (Th) cells in the context of MHC class II molecules have vaccine potential against cancer and infectious agents. We have described previously a melanoma patient's HLA-DR7-restricted Th cell clone recognizing an antigen, which is shared among melanoma and glioma cells derived from various patients. Here, this antigen was cloned using a novel antigen phage display approach. The antigen was identified as the ribosomal protein L8 (RPL8). A peptide of RPL8 significantly stimulated proliferation and/or cytokine expression of the Th cell clone and lymphocytes in four of nine HLA-DR7(+) melanoma patients but not in healthy volunteers. The RPL8 antigen may represent a relevant vaccine target for patients with melanoma, glioma, and breast carcinoma whose tumors express this protein.


Asunto(s)
Antígenos de Neoplasias/inmunología , Antígeno HLA-DR7/inmunología , Melanoma/inmunología , Proteínas Ribosómicas/inmunología , Animales , Antígenos de Neoplasias/genética , Células COS , Chlorocebus aethiops , Clonación Molecular , Epítopos/genética , Epítopos/inmunología , Humanos , Activación de Linfocitos , Melanoma/genética , Biblioteca de Péptidos , Proteínas Ribosómicas/genética , Linfocitos T Colaboradores-Inductores/inmunología
10.
Front Chem ; 7: 158, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-30984735

RESUMEN

Here we report the first theoretical characterization of the interface between the CuGaO2 delafossite oxide and the carboxylic (-COOH) and phosphonic acid (-PO3H2) anchoring groups. The promising use of delafossites as effective alternative to nickel oxide in p-type DSSC is still limited by practical difficulties in sensitizing the delafossite surface. Thus, this work provides atomistic insights on the structure and energetics of all the possible interactions between the anchoring functional groups and the CuGaO2 surface species, including the effects of the Mg doping and of the solvent medium. Our results highlight the presence of a strong selectivity toward the monodentate binding mode on surface Ga atoms for both the carboxylic and phosphonic acid groups. Since the binding modes have a strong influence on the hole injection thermodynamics, these findings have direct implications for further development of delafossite based p-type DSSCs.

11.
Cancer Res ; 66(6): 3287-93, 2006 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-16540682

RESUMEN

Mutated BRAF (BRAF(V600E)) is a potential immunotherapeutic target for melanoma because of its tumor specificity and expression in the majority of these lesions derived from different patients. BRAF(V600E) is expressed intracellularly and not on the cell surface, therefore providing a target for T cells but not B cells. Demonstration of patients' T cell responses to BRAF(V600E) would suggest the feasibility of active specific immunotherapy targeting the mutation in these patients. In the present study, BRAF(V600E) peptides with putative binding sites for human leukocyte antigen (HLA)-A2 were used to stimulate T lymphocytes of HLA-A2-positive melanoma patients. Four of five patients with BRAF(V600E)-positive lesions showed lymphoproliferative responses to BRAF(V600E) peptide stimulation. These responses were specific for the mutated epitope and HLA-A2 was restricted in three patients. Lymphocytes from these three patients were cytotoxic against HLA-A2-matched BRAF(V600E)-positive melanoma cells. None of the four patients with BRAF(V600E)-negative lesions and none of five healthy donors had lymphoproliferative responses specific for the mutated epitope. The high prevalence (approximately 50%) of HLA-A2 among melanoma patients renders HLA-A2-restricted BRAF(V600E) peptides attractive candidate vaccines for these patients.


Asunto(s)
Antígenos HLA-A/inmunología , Melanoma/inmunología , Melanoma/terapia , Proteínas Proto-Oncogénicas B-raf/inmunología , Proteínas Proto-Oncogénicas B-raf/uso terapéutico , Linfocitos T Citotóxicos/inmunología , Sitios de Unión , Línea Celular Tumoral , Citocinas/inmunología , Citocinas/metabolismo , Epítopos de Linfocito T/genética , Epítopos de Linfocito T/inmunología , Antígeno HLA-A2 , Humanos , Inmunoterapia Adoptiva , Activación de Linfocitos , Mutación , Fragmentos de Péptidos/genética , Fragmentos de Péptidos/inmunología , Fragmentos de Péptidos/uso terapéutico , Proteínas Proto-Oncogénicas B-raf/genética
12.
Cancer Biol Ther ; 5(10): 1304-12, 2006 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-16929176

RESUMEN

Our previous analysis of the role of chemokines in T lymphocyte trafficking toward human tumor cells revealed the migration of a melanoma patient's cytotoxic T lymphocytes (CTL) toward autologous tumor cells, resulting in tumor cell apoptosis, in an organotypic melanoma culture. CTL migration was mediated by CX chemokine receptor (CXCR) 4 expressed by the CTL and CX chemokine ligand (CXCL) 12 secreted by the tumor cells, as evidenced by blockage of CTL migration by antibodies to CXCL12 or CXCR4, high concentrations of CXCL12 or small molecule CXCR4 antagonist. Here, we present the results of T cell migration in one additional melanoma patient and T cell and tumor cell analyses for CXCR4 and CXCL12 expression, respectively, in 12 additional melanoma patients, indicating the preferential role of CXCR4 and CXCL12 in CTL migration toward melanoma cells. These studies add to the increasing body of evidence suggesting that CXCL12 is a potent chemoattractant for T cells.


Asunto(s)
Quimiocinas CXC/inmunología , Melanoma/inmunología , Receptores CXCR4/inmunología , Linfocitos T Citotóxicos/inmunología , Linfocitos T/inmunología , Línea Celular Tumoral , Movimiento Celular , Quimiocina CXCL12 , Quimiotaxis , Citotoxicidad Inmunológica , Humanos , Melanoma/secundario
13.
Cancer Res ; 62(18): 5267-72, 2002 Sep 15.
Artículo en Inglés | MEDLINE | ID: mdl-12234995

RESUMEN

Cancer patients often develop CTLs that lyse autologous tumor cells in culture. However, tumors can progress in vivo despite the presence of CTLs. Various mechanisms have been reported to down-modulate CTL functions. In this study, the role of CD4+/CD25+ regulatory T cells in CTL induction and proliferation of established CTLs was investigated in a patient with CRC. CD4+ cytotoxic and regulatory T-cell lines were derived from the peripheral blood mononuclear cells of the same patient in mixed-lymphocyte tumor culture. The cytotoxic T-cell line and a clonal derivative specifically lysed the autologous tumor cells but not the B lymphocytes. Only HLA-A1-matched allogeneic CRC cells were lysed by the CTL clone. The clone produced IFN-gamma and TNF-alpha. The regulatory CD4+/CD25+ T-cell line was tumor cell-dependent in its growth but did not lyse autologous tumor cells. This T-cell line suppressed pokeweed mitogen responses of allogeneic lymphocytes, proliferative activity of the established, autologous CTLs, and induction of CTLs in autologous, freshly isolated peripheral blood mononuclear cells. The immunosuppressive effect of the CD4+/CD25+ regulatory T cells was mediated by transforming growth factor-beta and did not require cell-to-cell contact. Thus, although CRC patients can develop specific CTLs against their tumors, the development of regulatory T cells may allow the escape of tumor cells from immune surveillance by the CTLs in vivo.


Asunto(s)
Antígenos CD4/inmunología , Neoplasias Colorrectales/inmunología , Receptores de Interleucina-2/inmunología , Linfocitos T Citotóxicos/inmunología , Factor de Crecimiento Transformador beta/inmunología , Animales , Técnicas de Cocultivo , Antígeno HLA-A1/inmunología , Humanos , Activación de Linfocitos/inmunología , Ratones , Ratones Desnudos , Ratones SCID , Células Tumorales Cultivadas
14.
J Transl Med ; 3: 41, 2005 Nov 10.
Artículo en Inglés | MEDLINE | ID: mdl-16281981

RESUMEN

A CD8+ cytotoxic T lymphocyte (CTL) line was derived from the peripheral blood mononuclear cells of a patient with primary melanoma. The CD8+ CTL line specifically lysed the autologous primary melanoma cells and not the natural killer cell-sensitive K562 cells or lymphokine activated killer cell-sensitive DAUDI cells. When a large panel of human leukocyte antigen (HLA)-matched and -unmatched allogeneic melanoma, glioma, breast and colorectal carcinoma cells was tested as targets in cytolysis assays, 4 HLA-matched and two HLA-unmatched allogeneic metastatic melanoma lines were lysed by the CD8+ CTL. Lysis of autologous and allogeneic melanoma cells was dependent on the effector-to-target cell ratio. Lysis of autologous melanoma cells was not blocked by anti-HLA class I or class II antibodies, confirming that the cytolytic activity of the CD8+ CTL was HLA-unrestricted. CTL lysis of autologous melanoma cells was CD3 (T cell receptor) dependent and FAS-FAS-L, and CD1 independent. Identification of the melanoma-associated antigen recognized by the HLA-unrestricted CTL may provide a vaccine for a broad population of melanoma patients.

15.
J Lipid Res ; 49(3): 625-34, 2008 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-18073406

RESUMEN

Increased mitochondrial ceramide levels are associated with the initiation of apoptosis. There is evidence that ceramide is causal. Thus, the conversion of the precursor, dihydroceramide, to ceramide by the enzyme dihydroceramide desaturase may be important in preparing the cell for apoptosis. Ceramide can initiate apoptosis by permeabilizing the mitochondrial outer membrane to apoptosis-inducing proteins. However, the mitochondrion's ability to produce ceramide may be limited by its proteome. Here, we show that ceramide synthesized in isolated mammalian endoplasmic reticulum (ER) vesicles from either C8-dihydroceramide or sphingosine to produce long-chain ceramide can transfer to isolated mitochondria. The rate of transfer is consistent with a simple collision model. The transfer of the long-chain ceramide is faster than expected for an uncatalyzed process. Sufficient ceramide is transferred to permeabilize the outer membrane to cytochrome c and adenylate kinase. The mitochondria-associated membranes, ER-like membranes that are tightly associated with isolated mitochondria, can produce enough ceramide to permeabilize the outer membrane transiently. Thus, this ceramide exchange obviates the need for a complete ceramide de novo pathway in mitochondria to increase ceramide levels to the critical value required for functional changes, such as ceramide channel self-assembly followed by protein release.


Asunto(s)
Proteínas Reguladoras de la Apoptosis/metabolismo , Ceramidas/biosíntesis , Retículo Endoplásmico/metabolismo , Membranas Mitocondriales/fisiología , Adenilil Ciclasas , Animales , Fraccionamiento Celular , Ceramidas/metabolismo , Citocromos c/metabolismo , Microsomas , Mitocondrias , Permeabilidad , Transporte de Proteínas , Ratas , Ratas Sprague-Dawley
16.
Cancer Immunol Immunother ; 56(3): 359-70, 2007 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-16783574

RESUMEN

Adoptive immunotherapy of cancer patients with cytolytic T lymphocytes (CTL) has been hampered by the inability of the CTL to home into tumors in vivo. Chemokines can attract T lymphocytes to the tumor site, as demonstrated in animal models, but the role of chemokines in T-lymphocyte trafficking toward human tumor cells is relatively unexplored. In the present study, the role of chemokines and their receptors in the migration of a colon carcinoma (CC) patient's CTL toward autologous tumor cells has been studied in a novel three-dimensional organotypic CC culture. CTL migration was mediated by chemokine receptor CXCR3 expressed by the CTL and CXCL11 chemokine secreted by the tumor cells. Excess CXCL11 or antibodies to CXCL11 or CXCR3 inhibited migration of CTL to tumor cells. T cell and tumor cell analyses for CXCR3 and CXCL11 expression, respectively, in ten additional CC samples, may suggest their involvement in other CC patients. Our studies, together with previous studies indicating angiostatic activity of CXCL11, suggest that CXCL11 may be useful as an immunotherapeutic agent for cancer patients when transduced into tumor cells or fused to tumor antigen-specific Ab.


Asunto(s)
Movimiento Celular/inmunología , Quimiocinas CXC/inmunología , Neoplasias del Colon/inmunología , Receptores de Quimiocina/inmunología , Linfocitos T Citotóxicos/inmunología , Apoptosis/inmunología , Línea Celular Tumoral , Quimiocina CXCL11 , Quimiocinas CXC/biosíntesis , Citocinas/análisis , Ensayo de Inmunoadsorción Enzimática , Femenino , Humanos , Fenotipo , Receptores CXCR3 , Receptores de Quimiocina/biosíntesis , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Sensibilidad y Especificidad , Técnicas de Cultivo de Tejidos
17.
Eur J Immunol ; 36(2): 457-67, 2006 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-16421945

RESUMEN

Studies in experimental animal models have demonstrated that chemokines produced by tumor cells attract chemokine receptor-positive T lymphocytes into the tumor area. However, in cancer patients, the role of chemokines in T lymphocyte trafficking toward human tumor cells is relatively unexplored. In the present study, the migration of a melanoma patient's CTL toward autologous tumor cells has been studied in a novel three-dimensional organotypic melanoma culture. In this model, CTL migrated toward tumor cells, resulting in tumor cell apoptosis. CTL migration was mediated by the CC chemokine receptor (CCR)4 expressed by the CTL and the CC chemokine ligand (CCL)2 secreted by the tumor cells, as evidenced by blockage of CTL migration by CCL2 or antibodies to CCL2 or CCR4. These results were confirmed in a Transwell migration assay in which the CTL actively migrated toward isolated CCL2 and migration was inhibited by anti-CCR4 antibody. These studies, together with previous studies in mice indicating regression of CCL2-transduced tumor cells, suggest that CCL2 may be useful as an immunotherapeutic agent for cancer patients.


Asunto(s)
Apoptosis/inmunología , Quimiocina CCL2/inmunología , Quimiotaxis/inmunología , Melanoma/inmunología , Receptores de Quimiocina/inmunología , Linfocitos T Citotóxicos/inmunología , Animales , Anticuerpos Monoclonales/inmunología , Anticuerpos Monoclonales/farmacología , Apoptosis/efectos de los fármacos , Técnicas de Cultivo de Célula , Quimiocina CCL2/uso terapéutico , Quimiotaxis/efectos de los fármacos , Femenino , Humanos , Melanoma/tratamiento farmacológico , Melanoma/patología , Ratones , Receptores CCR4 , Linfocitos T Citotóxicos/patología , Células Tumorales Cultivadas
18.
J Immunol ; 174(9): 5856-63, 2005 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-15843590

RESUMEN

Studies in experimental animal models have demonstrated that chemokines produced by tumor cells attract chemokine receptor-positive T lymphocytes into the tumor area, which may lead to tumor growth inhibition in vitro and in vivo. However, in cancer patients, the role of chemokines in T lymphocyte trafficking toward human tumor cells is relatively unexplored. In the present study, the role of chemokines and their receptors in the migration of a melanoma patient's CTL toward autologous tumor cells has been studied in a novel organotypic melanoma culture, consisting of a bottom layer of collagen type I with embedded fibroblasts followed successively by a tumor cell layer, collagen/fibroblast separating layer, and, finally, a top layer of collagen with embedded fibroblasts and T cells. In this model, CTL migrated from the top layer through the separating layer toward tumor cells, resulting in tumor cell apoptosis. CTL migration was mediated by chemokine receptor CXCR4 expressed by the CTL and CXCL12 (stromal cell-derived factor 1alpha) secreted by tumor cells, as evidenced by blockage of CTL migration by Abs to CXCL12 or CXCR4, high concentrations of CXCL12 or small molecule CXCR4 antagonist. These studies, together with studies in mice indicating regression of CXCL12-transduced tumor cells, followed by regression of nontransduced challenge tumor cells, suggest that CXCL12 may be useful as an immunotherapeutic agent for cancer patients, when transduced into tumor cells, or fused to anti-tumor Ag Ab or tumor Ag.


Asunto(s)
Quimiocinas CXC/fisiología , Quimiotaxis de Leucocito/inmunología , Melanoma/inmunología , Melanoma/patología , Receptores CXCR4/fisiología , Linfocitos T Citotóxicos/inmunología , Adulto , Apoptosis/inmunología , Línea Celular Tumoral , Quimiocina CXCL12 , Quimiocinas CXC/biosíntesis , Técnicas de Cocultivo , Humanos , Inmunofenotipificación , Células K562 , Prueba de Cultivo Mixto de Linfocitos , Masculino , Técnicas de Cultivo de Órganos , Receptores CXCR4/biosíntesis , Células del Estroma/inmunología , Linfocitos T Citotóxicos/citología , Linfocitos T Citotóxicos/metabolismo
19.
Int J Cancer ; 104(3): 362-8, 2003 Apr 10.
Artículo en Inglés | MEDLINE | ID: mdl-12569560

RESUMEN

CD4(+) Th cells that are restricted by MHC class II molecules play an important role in the induction of antitumor immune responses. We have established a stable CD4(+) Th cell clone (Th35-1A) from the PBMCs of a patient with primary cutaneous melanoma. The Th cell clone is noncytolytic and proliferates specifically in the presence of irradiated autologous melanoma cells or autologous EBV-transformed B cells pulsed with melanoma tumor cell lysates. Th35-1A produces IFN-gamma (a Th1-type cytokine) after autologous tumor cell stimulation, and its proliferative reactivity is HLA class II-restricted. Th cells showed helper activity for PWM responses of PBMCs. Using a panel of HLA class II-matched and unmatched EBV-B cells as APCs and allogeneic melanoma tumor cell lysate as stimulant, DR7 was delineated as the HLA class II restriction element used by the Th cell clone. In agreement with these results, transfection of an allogeneic melanoma cell line with HLA-DR7 isolated from autologous EBV-B cells rendered the cell line stimulatory for Th35-1A cells. Specificity studies using autologous EBV-B cells (EBV-B35) pulsed with a panel of allogeneic tumor cell lysates of various tissue origins indicated that the Th cell clone recognizes an antigen shared by melanoma and glioma cells. The availability of the Th cell clone may lead to the development of new therapies against melanoma, using adoptive Th cell transfer and/or active immunization with a shared Th cell antigen.


Asunto(s)
Antígenos de Neoplasias/inmunología , Linfocitos T CD4-Positivos/inmunología , Glioma/inmunología , Antígeno HLA-DR7/inmunología , Melanoma/inmunología , Células TH1/inmunología , Anticuerpos Monoclonales/inmunología , División Celular , Línea Celular Transformada , Transformación Celular Viral , Células Clonales , Técnicas de Cocultivo , Citocinas/metabolismo , Citotoxicidad Inmunológica , Antígeno HLA-DR7/genética , Antígenos de Histocompatibilidad Clase I/inmunología , Humanos , Activación de Linfocitos , Linfocitos Infiltrantes de Tumor , Linfocitos T Citotóxicos/inmunología , Transfección , Células Tumorales Cultivadas
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