Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 38
Filtrar
Más filtros












Base de datos
Intervalo de año de publicación
1.
Arch Pathol Lab Med ; 148(4): 385-389, 2024 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-37787422

RESUMEN

CONTEXT.­: Myelodysplasia cutis is an emerging concept in cutaneous neoplasia. Many of these cases were previously included under the umbrella of histiocytoid Sweet syndrome. However, with the advent of next-generation sequencing, cutaneous involvement by myelodysplastic syndrome is being increasingly recognized. OBJECTIVE.­: To review histiocytoid Sweet syndrome and myelodysplasia cutis and discuss our current understanding of these entities. Additionally, to discuss how next-generation sequencing can be applied in the evaluation of cutaneous infiltrates of immature histiocytoid cells. DATA SOURCES.­: The English-language literature from 2005 to 2023 on the topic of histiocytoid Sweet syndrome and myelodysplasia cutis was reviewed. CONCLUSIONS.­: Biopsy specimens showing infiltrates of histiocytoid, immature myeloid cells may represent cutaneous involvement by myelodysplastic syndrome. Close clinical correlation is recommended in these cases. Recent studies suggest that next-generation sequencing is useful in separating myelodysplasia cutis from true histiocytoid Sweet syndrome. This distinction has important implications for patients.


Asunto(s)
Síndromes Mielodisplásicos , Neoplasias Cutáneas , Síndrome de Sweet , Humanos , Síndromes Mielodisplásicos/diagnóstico , Síndromes Mielodisplásicos/genética , Síndromes Mielodisplásicos/patología , Piel/patología , Neoplasias Cutáneas/patología , Síndrome de Sweet/diagnóstico , Síndrome de Sweet/patología
4.
Am J Clin Pathol ; 148(6): 523-528, 2017 Nov 20.
Artículo en Inglés | MEDLINE | ID: mdl-29140408

RESUMEN

OBJECTIVES: Philadelphia chromosome-like (Ph-like) genetic alterations define a subset of B lymphoblastic leukemia/lymphoma (B-ALL), which represents a separate provisional entity in the World Health Organization 2016 updated classification. However, these alterations have not been described outside the context of B-ALL. METHODS: Cytogenomic array and molecular analysis identified a Ph-like signature in a mixed-phenotype acute leukemia (MPAL), B/myeloid, confirmed using conventional immunophenotypic and cytochemical analysis. RESULTS: Flow cytometry identified a blast population demonstrating a B-cell lineage and myeloperoxidase positivity. A P2RY8-CRLF2 fusion and JAK1 mutation were detected, both of which are associated with Ph-like features. CONCLUSIONS: To our knowledge, this is the first report of Ph-like MPAL, which may represent a new diagnostic entity. We emphasize the need for refinement of diagnostic criteria for MPALs and highlight an opportunity for expansion of inclusion criteria in ongoing clinical trials studying the use of tyrosine kinase inhibitor therapy to include cases of Ph-like MPAL.


Asunto(s)
Linfocitos B/patología , Janus Quinasa 1/genética , Mutación , Cromosoma Filadelfia , Leucemia-Linfoma Linfoblástico de Células Precursoras/patología , Receptores de Citocinas/metabolismo , Receptores Purinérgicos P2Y/metabolismo , Enfermedad Aguda , Citometría de Flujo/métodos , Humanos , Inmunofenotipificación/métodos , Masculino , Mutación/genética , Fenotipo , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Adulto Joven
5.
Am J Hematol ; 91(12): E491-E495, 2016 12.
Artículo en Inglés | MEDLINE | ID: mdl-27649045

RESUMEN

Cutaneous T-cell lymphomas (CTCL), with few exceptions, remain incurable and treatment is largely palliative. We performed a retrospective analysis of systemic treatment outcomes of patients diagnosed with MF/SS. We identified 223 patients with MF/SS evaluated at a single institution from 1997 to 2013. Disease stage at diagnosis, time of treatment, and treatments received were retrospectively analyzed using our CTCL database. The primary endpoint was time to next treatment (TTNT). Treatment outcomes were analyzed using Kaplan-Meier method and comparisons among groups were made using log-rank analysis. A superior TTNT was associated with retinoid or interferon therapies when compared with HDAC inhibitors or systemic chemotherapy. Retinoids and interferon were associated with superior TTNT in both limited-stage and advanced stage disease. Extracorporeal photophoresis (ECP) had a superior TTNT in Sezary Syndrome. HDAC inhibitors and chemotherapy were associated with inferior TTNT in both limited stage disease and advanced stage disease. With the exception of interferon, retinoids, or ECP, durable responses are rarely achieved with systemic therapies in MF/SS patients, particularly those with advanced-stage disease. Therefore, clinical trial participation with novel agents should be encouraged. Am. J. Hematol. 91:E491-E495, 2016. © 2016 Wiley Periodicals, Inc.


Asunto(s)
Inhibidores de Histona Desacetilasas/uso terapéutico , Interferones/uso terapéutico , Micosis Fungoide/tratamiento farmacológico , Fotoféresis/métodos , Retinoides/uso terapéutico , Síndrome de Sézary/tratamiento farmacológico , Humanos , Persona de Mediana Edad , Estudios Retrospectivos , Resultado del Tratamiento
6.
Int J Mol Sci ; 17(7)2016 Jun 28.
Artículo en Inglés | MEDLINE | ID: mdl-27367671

RESUMEN

Ceramides are a central unit of all sphingolipids which have been identified as sites of biological recognition on cellular membranes mediating cell growth and differentiation. Several glycosphingolipids have been isolated, displaying immunomodulatory and anti-tumor activities. These molecules have generated considerable interest as potential vaccine adjuvants in humans. Accurate analyses of these and related sphingosine analogues are important for the characterization of structure, biological function, and metabolism. We report the complementary use of direct laser desorption ionization (DLDI), sheath flow electrospray ionization (ESI) Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS) and high-field nuclear magnetic resonance (NMR) analysis for the rapid, accurate identification of hexacosanoylceramide and starting materials. DLDI does not require stringent sample preparation and yields representative ions. Sheath-flow ESI yields ions of the product and byproducts and was significantly better than monospray ESI due to improved compound solubility. Negative ion sheath flow ESI provided data of starting materials and products all in one acquisition as hexacosanoic acid does not ionize efficiently when ceramides are present. NMR provided characterization of these lipid molecules complementing the results obtained from MS analyses. NMR data was able to differentiate straight chain versus branched chain alkyl groups not easily obtained from mass spectrometry.


Asunto(s)
Espectrometría de Masa por Ionización de Electrospray/métodos , Espectroscopía Infrarroja por Transformada de Fourier/métodos , Esfingolípidos/análisis , Humanos , Espectroscopía de Resonancia Magnética
7.
Genes Chromosomes Cancer ; 55(4): 389-96, 2016 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-26865278

RESUMEN

Systemic mastocytosis (SM) is characterized by a clonal proliferation of aberrant mast cells within extracutaneous sites. In a subset of SM cases, a second associated hematologic non-mast cell disease (AHNMD) is also present, usually of myeloid origin. Polymerase chain reaction and targeted fluorescence in situ hybridization studies have provided evidence that, in at least some cases, the aberrant mast cells are related clonally to the neoplastic cells of the AHNMD. In this work, a single nucleotide polymorphism microarray (SNP-A) was used to characterize the cytogenetics of the aberrant mast cells from a patient with acute myeloid leukemia and concomitant mast cell leukemia associated with a KIT D816A mutation. The results demonstrate the presence of shared cytogenetic abnormalities between the mast cells and myeloid blasts, as well as additional abnormalities within mast cells (copy-neutral loss of heterozygosity) not detectable by routine karyotypic analysis. To our knowledge, this work represents the first application of SNP-A whole-genome scanning to the detection of shared cytogenetic abnormalities between the two components of a case of SM-AHNMD. The findings provide additional evidence of a frequent clonal link between aberrant mast cells and cells of myeloid AHNMDs, and also highlight the importance of direct sequencing for identifying uncommon activating KIT mutations.


Asunto(s)
Leucemia de Mastocitos/genética , Leucemia Mieloide Aguda/genética , Mastocitos/patología , Células Mieloides/patología , Biopsia , Médula Ósea/patología , Aberraciones Cromosómicas , Células Clonales , Enfermedades Hematológicas/complicaciones , Enfermedades Hematológicas/genética , Enfermedades Hematológicas/patología , Humanos , Cariotipo , Leucemia de Mastocitos/patología , Leucemia Mieloide Aguda/complicaciones , Leucemia Mieloide Aguda/patología , Masculino , Persona de Mediana Edad , Polimorfismo de Nucleótido Simple
8.
J Pharm Biomed Anal ; 122: 1-8, 2016 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-26821286

RESUMEN

A new 'compact mass detector' co-developed with an instrument manufacturer (Waters Corporation) as an interface for liquid chromatography (LC), specifically Ultra-high performance LC(®) (UPLC(®) or UHPLC) analysis was evaluated as a potential new Open Access (OA) LC-MS platform in the Drug Discovery and Early Development space. This new compact mass detector based platform was envisioned to provide increased reliability and speed while exhibiting significant cost, noise, and footprint reductions. The new detector was evaluated in batch mode (typically 1-3 samples per run) to monitor reactions and check purity, as well as in High Throughput Screening (HTS) mode to run 24, 48, and 96 well plates. The latter workflows focused on screening catalysis conditions, process optimization, and library work. The objective of this investigation was to assess the performance, reliability, and flexibility of the compact mass detector in the OA setting for a variety of applications. The compact mass detector results were compared to those obtained by current OA LC-MS systems, and the capabilities and benefits of the compact mass detector in the open access setting for chemists in the drug discovery and development space are demonstrated.


Asunto(s)
Cromatografía Líquida de Alta Presión/instrumentación , Cromatografía Líquida de Alta Presión/métodos , Descubrimiento de Drogas/instrumentación , Descubrimiento de Drogas/métodos , Espectrometría de Masas/instrumentación , Espectrometría de Masas/métodos , Reproducibilidad de los Resultados
9.
Am J Clin Pathol ; 143(2): 265-73, 2015 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-25596253

RESUMEN

OBJECTIVES: To describe a rare case of subcutaneous panniculitis-like T-cell lymphoma (SPTCL) with morphologic and immunophenotypic evidence of bone marrow involvement. METHODS: Biopsy specimens of skin and subcutis and bone marrow were examined using H&E-stained sections. Immunohistochemical studies for CD2, CD3, CD4, CD5, CD7, CD8, CD20, CD30, CD56, and granzyme B were reviewed. In addition, T-cell receptor γ gene rearrangement studies were performed. RESULTS: A bone marrow core biopsy demonstrated several lymphohistiocytic aggregates containing atypical, cytotoxic T cells that rimmed adipocytes and were associated with karyorrhexis. These T cells were morphologically and immunophenotypically identical to a concurrent SPTCL, expressing CD2, CD3, CD7, CD8, and granzyme B but with diminished CD5 expression. CONCLUSIONS: SPTCL may rarely involve the bone marrow. Bone marrow infiltrates show a similar morphologic and immunophenotypic appearance to those in the subcutaneous fibroadipose tissue, including rimming of adipocytes by neoplastic lymphocytes.


Asunto(s)
Médula Ósea/patología , Linfoma de Células T/patología , Paniculitis/patología , Adulto , Médula Ósea/inmunología , Femenino , Humanos , Inmunohistoquímica , Inmunofenotipificación , Linfoma de Células T/inmunología , Paniculitis/inmunología
10.
Am J Clin Pathol ; 142(3): 398-410, 2014 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-25125632

RESUMEN

OBJECTIVES: Multiparameter flow cytometry (MFC) is a widely available laboratory platform for the evaluation of plasma cell (PC) neoplasms. We assess the performance of a nine-color MFC assay that uses stain-lyse-fix processing of bone marrow aspirates, minimal wash steps, and high acquisition rates with analysis of up to 1.8 × 10(6) cells. METHODS: MFC results were compared with microscopic examinations, immunohistochemical studies, and serum/urine M-protein measurements from patients with documented or suspected PC neoplasms. RESULTS: Sensitivity exceeded that of microscopic examinations, with or without immunohistochemistry. In patients with PC myeloma, clonal PC detection by MFC fell in concert with M-protein levels. However, in a subset of patients, MFC detected clonal PCs after serum/urine studies turned negative. CONCLUSIONS: The nine-color analytic cocktail eliminates duplication of PC gating reagents required for evaluation of the same epitopes using a five- or six-color approach. Fewer analytic cocktails result in lower instrument acquisition times per case, a significant factor for the large data sets required for optimal residual disease assessment. Finally, concurrent analysis of nine epitopes and two light scatter parameters aids detection of residual disease, particularly when it is mixed with polyclonal PCs.


Asunto(s)
Médula Ósea/patología , Citometría de Flujo/métodos , Neoplasias de Células Plasmáticas/diagnóstico , Células Plasmáticas/patología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Médula Ósea/inmunología , Forma de la Célula , Femenino , Humanos , Inmunofenotipificación , Masculino , Persona de Mediana Edad , Neoplasias de Células Plasmáticas/inmunología , Neoplasias de Células Plasmáticas/patología , Células Plasmáticas/inmunología , Adulto Joven
12.
J Cutan Pathol ; 41(6): 494-503, 2014 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-24467775

RESUMEN

CD20 expression is exceedingly rare in T-cell lymphomas. Most published cases have been diagnosed as peripheral T-cell lymphomas, not otherwise specified. Only 18 cases of CD20-positive mycosis fungoides (MF) have been previously reported. Here, we describe two cases of CD20-positive MF. Patient 1 was an 84-year-old woman who presented with a 5-year history of multiple pruritic erythematous papules coalescing into thin plaques over 80% of her body surface area. She expired after developing tumors and large cell transformation. Patient 2 was a 67-year-old woman with a long-standing history of tumor stage MF with large cell transformation. She developed a nodular plaque while receiving topical and systemic therapy. In both cases, the neoplastic T-cells demonstrated a CD4-positive immunophenotype with loss of pan-T-cell markers and a monoclonal T-cell receptor gamma gene rearrangement. CD20 was expressed by a significant population of the neoplastic T-cells, but these T-cells lacked expression of other B-cell markers, including CD79a, CD19 and PAX5. This report adds to and summarizes the small body of literature describing CD20-positive MF, and discusses diagnostic and clinical implications.


Asunto(s)
Antígenos CD20/metabolismo , Transformación Celular Neoplásica/metabolismo , Micosis Fungoide/metabolismo , Neoplasias Cutáneas/metabolismo , Linfocitos T/metabolismo , Anciano , Anciano de 80 o más Años , Transformación Celular Neoplásica/patología , Femenino , Humanos , Micosis Fungoide/patología , Neoplasias Cutáneas/patología , Linfocitos T/patología
13.
J Pediatr Hematol Oncol ; 35(3): e130-3, 2013 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-23425998

RESUMEN

We report an unusual case of an extranodal marginal zone B-cell lymphoma (EMZL) arising in the labial minor salivary gland in an immunocompetent 11-year-old boy. The initial histopathologic review favored localized amyloidosis. However, further evaluation supported the diagnosis of low-grade B-cell lymphoma with plasmacytic differentiation, surrounded by deposits of AL κ-type amyloid. Clinical management consisted of excision with no recurrence at 1-year follow-up. This case demonstrates that a diagnosis of lymphoma must be considered in cases of amyloidosis associated with minor salivary gland involvement, even in children. In addition, we provide a literature review of extranodal marginal zone B-cell lymphoma arising in salivary glands.


Asunto(s)
Amiloidosis/diagnóstico , Neoplasias de los Labios/diagnóstico , Linfoma de Células B de la Zona Marginal/diagnóstico , Glándulas Salivales Menores/patología , Amiloidosis/complicaciones , Amiloidosis/cirugía , Niño , Diagnóstico Diferencial , Humanos , Neoplasias de los Labios/complicaciones , Neoplasias de los Labios/cirugía , Linfoma de Células B de la Zona Marginal/complicaciones , Linfoma de Células B de la Zona Marginal/cirugía , Masculino , Literatura de Revisión como Asunto
14.
J Org Chem ; 77(12): 5331-44, 2012 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-22607128

RESUMEN

Proline derivatives with a C(γ)-exo pucker typically display a high amide bond trans/cis (K(T/C)) ratio. This pucker enhances n→π* overlap of the amide oxygen and ester carbonyl carbon, which favors a trans amide bond. If there were no difference in n→π* interaction between the ring puckers, then the correlation between ring pucker and K(T/C) might be broken. To explore this possibility, proline conformations were constrained using a methylene bridge. We synthesized discrete gauche and anti 5-fluoro- and 5-hydroxy-N-acetylmethanoproline methyl esters from 3-syn and 3-anti fluoro- and hydroxymethanopyrrolidines using directed α-metalation to introduce the α-ester group. NBO calculations reveal minimal n→π* orbital interactions, so contributions from other forces might be of greater importance in determining K(T/C) for the methanoprolines. Consistent with this hypothesis, greater trans amide preferences were found in CDCl(3) for anti isomers en-MetFlp and en-MetHyp (72-78% trans) than for the syn stereoisomers ex-MetFlp and ex-MetHyp (54-67% trans). These, and other, K(T/C) results that we report here indicate how substituents on proline analogues can affect amide preferences by pathways other than ring puckering and n→π* overlap and suggest that caution should be exercised in assigning enhanced pyrrolidine C(γ)-exo ring puckering based solely on enhanced trans amide preference.


Asunto(s)
Prolina/análogos & derivados , Pirrolidinas/química , Pirrolidinas/síntesis química , Conformación Molecular , Prolina/síntesis química , Prolina/química , Estereoisomerismo , Termodinámica
15.
Br J Haematol ; 158(4): 472-80, 2012 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-22640031

RESUMEN

The combination of lenalidomide-dexamethasone is active in multiple myeloma (MM). Preclinical data showed that the Akt inhibitor, perifosine, sensitized MM cells to lenalidomide and dexamethasone, providing the rationale for this Phase I, multicentre, single-arm study to assess the safety and determine the maximum-tolerated dose (MTD) of perifosine-lenalidomide-dexamethasone in relapsed and relapsed/refractory MM. Patients received escalating doses of perifosine 50-100 mg daily and lenalidomide 15-25 mg once daily on days 1-21 of each 28-d cycle, plus dexamethasone 20-40 mg weekly thereafter, as indicated. Thirty-two patients were enrolled across four dose cohorts. MTD was not reached, with 31 patients evaluable for safety/tolerability. The most common all-causality grade 1-2 adverse events were fatigue (48%) and diarrhoea (45%), and grade 3-4 neutropenia (26%), hypophosphataemia (23%), thrombocytopenia (16%), and leucopenia (13%). Among 30 evaluable patients, 73% (95% confidence interval, 57·5-89·2%) achieved a minimal response or better, including 50% with a partial response or better. Median progression-free survival was 10·8 months and median overall survival 30·6 months. Response was associated with phospho-Akt in pharmacodynamic studies. Perifosine-lenalidomide-dexamethasone was well tolerated and demonstrated encouraging clinical activity in relapsed and relapsed/refractory MM.


Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Mieloma Múltiple/tratamiento farmacológico , Adulto , Anciano , Protocolos de Quimioterapia Combinada Antineoplásica/administración & dosificación , Protocolos de Quimioterapia Combinada Antineoplásica/efectos adversos , Dexametasona/administración & dosificación , Dexametasona/efectos adversos , Relación Dosis-Respuesta a Droga , Esquema de Medicación , Femenino , Humanos , Estimación de Kaplan-Meier , Lenalidomida , Masculino , Persona de Mediana Edad , Mieloma Múltiple/metabolismo , Fosfatidilinositol 3-Quinasa/metabolismo , Fosforilcolina/administración & dosificación , Fosforilcolina/efectos adversos , Fosforilcolina/análogos & derivados , Proteínas Proto-Oncogénicas c-akt/metabolismo , Recurrencia , Talidomida/administración & dosificación , Talidomida/efectos adversos , Talidomida/análogos & derivados , Resultado del Tratamiento
16.
J Org Chem ; 76(10): 3626-34, 2011 May 20.
Artículo en Inglés | MEDLINE | ID: mdl-21500838

RESUMEN

N-acetylmethanopyrrolidine methyl ester and its four 5-syn/anti-fluoro and hydroxy derivatives have been synthesized from 2-azabicyclo[2.2.0]hex-5-ene, a 1,2-dihydropyridine photoproduct. These conformationally constrained mimics of idealized C(ß)-gauche and C(ß)-anti conformers of pyrrolidines were prepared in order to determine the inherent bridge bias and subsequent heteroatom substituent effects upon trans/cis amide preferences. The bridgehead position and also the presence of gauche(syn)/anti-5-fluoro or 5-hydroxy substituents have minimal influence upon the K(T/C) values of N-acetylamide conformers in both CDCl(3) (43-54% trans) and D(2)O (53-58% trans). O-Benzoylation enhances the trans amide preferences in CDCl(3) (65% for a syn-OBz, 61% for an anti-OBz) but has minimal effect in D(2)O. The synthetic methods developed for N-BOC-methanopyrrolidines should prove useful in the synthesis of more complex derivatives containing α-ester substituents. The K(T/C) results obtained in this study establish baseline amide preferences that will enable determination of contributions of α-ester substituents to trans-amide preferences in methanoprolines.


Asunto(s)
Conformación Molecular , Pirrolidinas/química , Pirrolidinas/síntesis química , Amidas/química , Prolina/química , Estereoisomerismo
17.
PLoS One ; 5(10): e13657, 2010 Oct 27.
Artículo en Inglés | MEDLINE | ID: mdl-21048959

RESUMEN

Parathyroid hormone (PTH) stimulates hematopoietic cells through mechanisms of action that remain elusive. Interleukin-6 (IL-6) is upregulated by PTH and stimulates hematopoiesis. The purpose of this investigation was to identify actions of PTH and IL-6 in hematopoietic cell expansion. Bone marrow cultures from C57B6 mice were treated with fms-like tyrosine kinase-3 ligand (Flt-3L), PTH, Flt-3L plus PTH, or vehicle control. Flt-3L alone increased adherent and non-adherent cells. PTH did not directly impact hematopoietic or osteoclastic cells but acted in concert with Flt-3L to further increase cell numbers. Flt-3L alone stimulated proliferation, while PTH combined with Flt-3L decreased apoptosis. Flt-3L increased blasts early in culture, and later increased CD45(+) and CD11b(+) cells. In parallel experiments, IL-6 acted additively with Flt-3L to increase cell numbers and IL-6-deficient bone marrow cultures (compared to wildtype controls) but failed to amplify in response to Flt-3L and PTH, suggesting that IL-6 mediated the PTH effect. In vivo, PTH increased Lin(-) Sca-1(+)c-Kit(+) (LSK) hematopoietic progenitor cells after PTH treatment in wildtype mice, but failed to increase LSKs in IL-6-deficient mice. In conclusion, PTH acts with Flt-3L to maintain hematopoietic cells by limiting apoptosis. IL-6 is a critical mediator of bone marrow cell expansion and is responsible for PTH actions in hematopoietic cell expansion.


Asunto(s)
Células de la Médula Ósea/efectos de los fármacos , División Celular/efectos de los fármacos , Interleucina-6/farmacología , Hormona Paratiroidea/fisiología , Animales , Western Blotting , Células de la Médula Ósea/citología , Adhesión Celular , Diferenciación Celular , Linaje de la Célula , Citometría de Flujo , Ratones , Ratones Endogámicos C57BL , Osteoblastos/citología , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa
18.
Org Lett ; 12(23): 5438-41, 2010 Dec 03.
Artículo en Inglés | MEDLINE | ID: mdl-21043445

RESUMEN

CD spectra for homooligomers (n = 4, 6, 8) of (1S,4R,5R)-5-syn-carboxy-2-azabicyclo[2.1.1]hexane (MPCA), a methano-bridged pyrrolidine ß-carboxylic acid, suggest an ordered secondary structure. Even in the absence of internal hydrogen bonding, solution NMR, X-ray, and in silico analyses of the tetramer are indicative of conformations with trans-amides and C(5)-amide-carbonyls oriented toward the C(4) bridgehead. This highly constrained ß-amino acid could prove useful in the ongoing development of well-defined foldamers.


Asunto(s)
Aminoácidos/química , Pirrolidinas/química , Modelos Moleculares , Estructura Molecular
19.
J Org Chem ; 74(21): 8232-42, 2009 Nov 06.
Artículo en Inglés | MEDLINE | ID: mdl-19799411

RESUMEN

Nucleophilic displacements of 5(6)-anti-bromo substituents in 2-azabicyclo[2.1.1]hexanes (methanopyrrolidines) have been accomplished. These displacements have produced 5-anti-X-6-anti-Y-difunctionalized-2-azabicyclo[2.1.1]hexanes containing bromo, fluoro, acetoxy, hydroxy, azido, imidazole, thiophenyl, and iodo substituents. Such displacements of anti-bromide ions require an amine nitrogen and are a function of the solvent and the choice of metal salt. Reaction rates were faster and product yields were higher in DMSO when compared to DMF and with CsOAc compared to NaOAc. Sodium or lithium salts gave products, except with NaF, where silver fluoride in nitromethane was best for substitution by fluoride. The presence of electron-withdrawing F, OAc, N(3), Br, or SPh substituents in the 6-anti-position slows bromide displacements at the 5-anti-position.


Asunto(s)
Compuestos de Azabiciclo/química , Hexanos/química , Cristalografía por Rayos X , Espectroscopía de Resonancia Magnética , Espectrometría de Masas
20.
J Clin Oncol ; 27(20): 3354-62, 2009 Jul 10.
Artículo en Inglés | MEDLINE | ID: mdl-19451438

RESUMEN

PURPOSE: We studied the incidence, risk factors, treatment, and outcomes of post-transplantation lymphoproliferative disorder (PTLD) that occurred at the University of Michigan since 1964. PATIENTS AND METHODS: We identified 7,040 patients who received solid organ transplantation (SOT) and post-transplantation immunosuppressive therapy. Seventy-eight patients developed PTLD. RESULTS: Diffuse large B-cell lymphoma (n = 43), polymorphic PTLD (n = 10), Hodgkin's lymphoma (n = 7), Burkitts lymphoma (n = 6), plasmacytoma (n = 5), and mucosa-associated lymphoid tissue lymphoma (n = 3) were all over-represented in the SOT population compared with a population sample from the Surveillance, Epidemiology, and End Results (SEER) database; follicular lymphoma (n = 0) was underrepresented. Negative pretransplantation Epstein-Barr virus (EBV) serology was a risk factor for PTLD. Available histologic analysis of tumor tissue showed that 75% were CD20 positive and that 62% were EBV positive; EBV-positive tumors occurred sooner after SOT than EBV-negative tumors (mean, 29 v 66 months). Extralymphatic disease (79%), poor performance status (68%), elevated lactate dehydrogenase (LDH; 71%), and advanced stage (68%) disease were all common at the time of lymphoma diagnosis. Two thirds of patients had a complete response when treated with cyclophosphamide, doxorubicin, vincristine, and prednisone-like chemotherapy (either with or without rituximab). Median overall survival in all patients with PTLD was 8.23 years (95% CI, 2.28 to 30.0 years). CONCLUSION: EBV-naïve patients who receive a donor organ from an EBV-infected donor are in the highest-risk situation for PTLD development. Most of these lymphomas are CD20 positive. Follicular lymphoma is unusual. With treatment, survival of patients with PTLD was indistinguishable from that of the SEER population sample.


Asunto(s)
Linfoma/etiología , Trastornos Linfoproliferativos/etiología , Trasplante de Órganos/efectos adversos , Adolescente , Adulto , Anciano , Infecciones por Virus de Epstein-Barr/complicaciones , Infecciones por Virus de Epstein-Barr/virología , Femenino , Herpesvirus Humano 4/genética , Herpesvirus Humano 4/metabolismo , Humanos , Inmunohistoquímica , Inmunosupresores/efectos adversos , Inmunosupresores/uso terapéutico , Hibridación in Situ , Estimación de Kaplan-Meier , Linfoma/diagnóstico , Linfoma/terapia , Trastornos Linfoproliferativos/diagnóstico , Trastornos Linfoproliferativos/terapia , Masculino , Michigan , Persona de Mediana Edad , ARN Viral/genética , Factores de Riesgo , Tacrolimus/efectos adversos , Tacrolimus/uso terapéutico , Resultado del Tratamiento , Proteínas de la Matriz Viral/metabolismo
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...