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2.
CMAJ ; 167(2): 172, 2002 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-12160130
3.
Ann N Y Acad Sci ; 941: 106-22, 2001 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-11594564

RESUMO

To develop cancer vaccines for the treatment of cutaneous T cell lymphoma (CTCL), immunogenic peptides were identified by two approaches. First, through the use of "reverse immunology" the peptide sequence of the idiotypic region of the beta chain of the T cell receptor (TCR) was determined and a series of overlapping peptides synthesized and tested for CD8 T cell recognition. In two patients, the idiotypic CDR3 region provided immunogenic epitopes that were recognized in a class I-restricted fashion by autologous CD8 T cell lines. In a second strategy, peptides were isolated directly from class I MHC molecules on the CTCL surface and sequenced. A peptide with partial homology to sequences contained in the conserved variable portion of the clonotypic TCR beta chain was recognized as immunogenic by autologous CD8 T cells. Therefore, both approaches demonstrated that the clonotypic TCR in CTCL is a source of immunogenic tumor epitopes. To confirm that recognition of TCR-derived sequences provides immunoprotection against tumor growth, a murine model of T cell lymphoma was studied. The immunogenicity of a thymoma, which lacks cell surface TCR expression, was enhanced by transfection of the beta chain of the TCR. The studies reviewed in this paper demonstrate that the TCR can serve as one source for immunogenic tumor peptides in T cell lymphoma in vitro and in vivo. Presentation of TCR epitopes on dendritic cells that express high levels of MHC, costimulatory, and adhesion molecules may provide an effective means for immunization against T cell malignancy.


Assuntos
Antígenos de Neoplasias/imunologia , Vacinas Anticâncer , Linfoma Cutâneo de Células T/terapia , Receptores de Antígenos de Linfócitos T/imunologia , Neoplasias Cutâneas/terapia , Sequência de Aminoácidos , Animais , Antígenos de Neoplasias/genética , Linfócitos T CD8-Positivos/imunologia , Linhagem Celular , Células Cultivadas , Humanos , Hibridomas , Idiótipos de Imunoglobulinas/imunologia , Ativação Linfocitária , Linfoma Cutâneo de Células T/imunologia , Camundongos , Transplante de Neoplasias , Peptídeos/imunologia , Receptores de Antígenos de Linfócitos T/genética , Neoplasias Cutâneas/imunologia , Taxa de Sobrevida , Linfócitos T Citotóxicos/imunologia , Transfecção
4.
Biochem Biophys Res Commun ; 280(4): 1042-7, 2001 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-11162632

RESUMO

Cyclooxygenase (COX) is the rate-limiting enzyme in the production of prostaglandins from arachidonic acid. This enzyme exists in at least two isoforms, COX-1 and COX-2. COX-1 is constitutively expressed in most tissues and plays various physiological roles. However, COX-2 expression is induced by a variety of agents, which include pro-inflammatory agents and mitogens. Evidence exists to indicate that increased expression of COX-2 occurs in several types of epithelial neoplasms. In this study, we show the effect of chronic exposure of murine skin to carcinogenic UVB on cutaneous COX-2 expression. SKH-1 mice were irradiated with 180 mJ/cm(2) UVB daily for five days a week for periods ranging from 1 to 20 weeks. Nontumor bearing skin areas of irradiated mice, skin of age-matched controls and benign papillomas and malignant tumors were assessed immunohistochemically for COX-2 expression in these mice. No epidermal staining occurred in any of the non-UVB-treated controls throughout the experiment. Epidermal COX-2 expression only occurred in UVB-irradiated mice. After 1 and 5 weeks of irradiation, patchy epidermal staining mostly confined to the granular layer and stratum corneum was observed. At week 9, staining intensity had increased, particularly in the granular layer. At week 13, staining was uniformly seen in all epidermal layers with particular prominence in the basal cell layer underlying areas of visible epidermal hyperplasia. It is of interest that the most intense staining was seen in the perinuclear region of keratinocytes and at the plasma membrane. At week 20, COX-2 staining was predominant in the granular layer, although in some tissue sections, the entire epidermis was positive. In benign papillomas, staining was confined to the superficial layers of the epidermis and in squamous cell carcinomas (SCCs), patchy staining in the granular and spinous layers predominated. In general, COX-2 expression was more intense in well-differentiated SCCs than in papillomas. In summary, our results indicate that COX-2 serves as an early marker of epidermal UVB exposure and its expression increases in benign papillomas and in SCCs. These results suggest that pharmacological intervention using specific COX-2 inhibitors could have anticarcinogenic effects in UVB-induced human skin cancer.


Assuntos
Carcinoma de Células Escamosas/metabolismo , Isoenzimas/biossíntese , Papiloma/metabolismo , Prostaglandina-Endoperóxido Sintases/biossíntese , Neoplasias Cutâneas/metabolismo , Pele/metabolismo , Animais , Carcinoma de Células Escamosas/patologia , Diferenciação Celular , Ciclo-Oxigenase 2 , Feminino , Imuno-Histoquímica , Camundongos , Neoplasias Induzidas por Radiação/metabolismo , Neoplasias Induzidas por Radiação/prevenção & controle , Papiloma/patologia , Isoformas de Proteínas , Pele/efeitos da radiação , Neoplasias Cutâneas/patologia , Fatores de Tempo , Raios Ultravioleta
6.
Semin Clin Neuropsychiatry ; 2(1): 94-98, 1997 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-10320447

RESUMO

Diabetes mellitus is a multisystem disorder characterized by abnormalities in glucose, fat, and protein metabolism. The long-term microvascular complications of diabetes such as retinopathy, nephropathy, and neuropathy are the same in both forms of the disease. In both types of the disease, diabetes education, frequent monitoring of blood glucose, and regular screening to detect and treat complications at an early stage are an integral part of diabetes management. Patients have to emotionally accept the diagnosis of diabetes and also face the fact that they may already have potentially debilitating complications. Lack of compliance by patients may be a sign of frustration; it signals that goals of treatment and the approach to therapy should be reevaluated. This evaluation should include attention to possible social and psychological issues that may not be immediately apparent. These issues include fear of diabetes and its complications, stress with family or in the workplace and underlying psychiatric conditions. Conversely, both hyperglycemia and hypoglycemia can be very stressful. The relationship between stress and blood glucose control is further complicated by the fact that patients under psychological stress often change their behavior in ways that impact on glucose control. Despite the tremendous progress already made in our understanding of pathophysiology of diabetes and treatment of hyperglycemia, one thing remains unchanged. Life with diabetes continues to be a significant effort and often an overwhelming burden. The disease is complicated, treatments can be complex and prescriptions for patient regimens are often confusing. Diabetes treatment is dependent to a large extent on the individual's ability to practice adequate daily self care, a skill that requires critical support by the health care team. A multidisciplinary approach that includes professionals experienced in psychosocial problems is invaluable in helping these patients.

7.
J Invest Dermatol ; 107(3): 392-7, 1996 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-8751976

RESUMO

In order to determine whether the neoplastic T cells from patients with cutaneous T-cell lymphoma express tumor-specific antigens that can serve as the targets of an immune response, we took advantage of family-specific monoclonal antibodies, magnetic bead technology, and recombinant cytokines, which provided the previously precluded ability to isolate and expand populations of purified tumor and autologous CD8 cytotoxic T cells. Four patients with advanced cutaneous T-cell lymphoma had CD8 cells that specifically killed autologous tumor in a class I limited fashion. Tumor cell cytolysis could be specifically enhanced by pre-culture with autologous gamma-irradiated tumor. The cytolytic T cells produced tumor necrosis factor-alpha in response to stimulation with autologous tumor. The presence of tumor-specific cytotoxic T cells recognizing distinctive class I associated molecules on cutaneous T-cell lymphoma tumor cells suggests that infiltration of early lesions by CD8 cells reflects host immunity to the neoplasm. These studies provide the foundation for the development of tumor vaccines through the use of cytotoxic T cells to isolate and characterize tumor-associated cutaneous T-cell lymphoma peptides.


Assuntos
Epitopos , Antígenos de Histocompatibilidade Classe I/imunologia , Linfoma Cutâneo de Células T/imunologia , Neoplasias Cutâneas/imunologia , Formação de Anticorpos , Linfócitos T CD8-Positivos/metabolismo , Linfócitos T CD8-Positivos/patologia , Divisão Celular , Células Cultivadas , Células Clonais , Humanos , Linfoma Cutâneo de Células T/genética , Linfoma Cutâneo de Células T/patologia , Fenótipo , Neoplasias Cutâneas/genética , Neoplasias Cutâneas/patologia , Linfócitos T Citotóxicos/imunologia , Linfócitos T Citotóxicos/fisiologia , Fator de Necrose Tumoral alfa/biossíntese
8.
Cancer ; 77(12): 2440-4, 1996 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-8640690

RESUMO

BACKGROUND: Human papillomaviruses (HPVs) commonly cause proliferative lesions of squamous epithelia, and infection with certain HPV types carries a high risk of malignant transformation, especially in the uterine cervix but also at other sites, including the esophagus. We used molecular techniques to detect and type HPV in an in situ squamous cell carcinoma in the esophagus of a 39-year old woman. METHODS: DNA was extracted from paraffin sections of the esophageal lesion and of the uterine cervix (which was removed several years earlier), and analyzed for HPV by polymerase chain reaction (PCR). Primers complementary to highly conserved regions of the open reading frame of most genital HPVs were used to amplify a approximately 450 base pair product that contained both conserved and divergent regions. The PCR products were hybridized with probes specific for HPV-6, HPV-11, HPV-16, and HPV-18, and with a consensus probe. A conspicuous band in the esophageal sample failed to hybridize with any of the probes. The amplimer was subcloned and sequenced. The sequence was compared with other known HPVs. RESULTS: The intraepithelial neoplasia in the patient's cervical cone biopsy contained HPV-16. The esophageal lesion contained HPV that did not hybridize with probes for types 6, 11, 16, or 18, but exhibited 98.3% homology with HPV-73. CONCLUSIONS: Squamous cell carcinoma in situ of the esophagus may be associated with infection by HPV-73.


Assuntos
Carcinoma in Situ/virologia , Carcinoma de Células Escamosas/virologia , Neoplasias Esofágicas/virologia , Papillomaviridae/crescimento & desenvolvimento , Infecções por Papillomavirus/virologia , Infecções Tumorais por Vírus/virologia , Adulto , Colo do Útero/virologia , Feminino , Humanos
9.
Am J Dermatopathol ; 17(5): 476-83, 1995 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-8599453

RESUMO

To determine the effect of different fixatives on the recovery and detection of mRNAs from archival histopathology specimens, biopsies of normal skin were fixed in neutral and alcohol-buffered formalin, acetone, Carnoy's fixative, methacarn, and Bouin's solution. Tissue was routinely processed, and sections were either mounted for in situ hybridization or deparaffinized for RNA extraction. Extracted mRNA was reverse-transcribed using random hexamers, and the resulting cDNA was amplified by the polymerase chain reaction using primers specific for glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and beta-actin. Amplification products of both GAPDH and actin could be detected by gel electrophoresis from tissues processed in all fixatives except Bouin's. A parallel study of formalin-fixed, paraffin-embedded archival biopsies accessioned since 1990 gave similar results. Less abundant mRNAs, such as those encoding interleukin-11 or the T-cell receptor beta-chain, could be detected by Southern blotting and hybridization with labeled oligonucleotide probes or by cloning and sequencing. In situ hybridization studies using oligonucleotide probes were most successful with tissue fixed in formalin, including both the experimentally fixed tissues and the archival biopsy samples. Thus, mRNAs may be isolated from and localized in formalin-fixed, paraffin-embedded archival material. Because dermatopathology laboratory archives typically contain samples from a wide spectrum of diseases that can be accessed without Human Investigation Committee approval, these laboratories represent a logical starting point for studying gene regulation and expression in skin.


Assuntos
Ácido Acético , Fixadores , RNA Mensageiro/análise , Dermatopatias/patologia , Pele/patologia , Fixação de Tecidos , Acetatos , Acetona , Actinas/genética , Biópsia , Southern Blotting , Clorofórmio , Sondas de DNA , DNA Complementar , Eletroforese , Etanol , Formaldeído , Amplificação de Genes , Regulação da Expressão Gênica , Gliceraldeído-3-Fosfato Desidrogenases/genética , Humanos , Hibridização In Situ , Interleucina-11/genética , Metanol , Inclusão em Parafina , Picratos , Reação em Cadeia da Polimerase , RNA Mensageiro/genética , Receptores de Antígenos de Linfócitos T alfa-beta/genética , Dermatopatias/genética , Transcrição Gênica
10.
Dermatol Surg ; 21(8): 725-7, 1995 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-7633821

RESUMO

BACKGROUND: There are a few tumors that exhibit inflammatory cutaneous metastases. This pattern is particularly difficult to diagnose since it can mimic erysipelas or lymphangitis. OBJECTIVE: This is a presentation of a 69-year-old woman diagnosed with poorly differentiated cloacogenic carcinoma who simultaneously was noted to have an abdominal rash. A biopsy confirmed cutaneous metastasis of her carcinoma. METHODS: Previously published literature on cutaneous metastases were reviewed and summarized. RESULTS: This is the first reported case of an inflammatory cutaneous metastasis arising from cloacogenic carcinoma. CONCLUSION: Cutaneous metastases can present in various forms, including the inflammatory pattern. Because this form mimics other conditions, it is prudent to biopsy any suspicious skin lesion in cancer patients, as it may considerably affect prognosis.


Assuntos
Neoplasias do Ânus/patologia , Carcinoma de Células de Transição/secundário , Neoplasias Cutâneas/secundário , Idoso , Carcinoma de Células de Transição/patologia , Feminino , Humanos , Inflamação , Neoplasias Cutâneas/patologia
11.
J Invest Dermatol ; 105(1): 62-4, 1995 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-7615977

RESUMO

Cutaneous T-cell lymphoma (CTCL) is a malignancy of mature T lymphocytes, most of which express alpha/beta type T-cell receptors (TCRs). The cause of CTCL is unknown, but hypotheses postulating chronic stimulation of TCRs by superantigen or by a leukemogenic virus have been proposed. Either mechanism might produce bias in the TCR variable (V) region types used by the malignant cells. To determine if TCR alpha use is restricted in CTCL, we used reverse transcription and the polymerase chain reaction to determine V alpha and V beta usage by malignant cells purified from the peripheral blood of leukemic patients with CTCL. Usage of alpha chain V region segments appeared totally random; malignant lymphocytes isolated from each of six patients used different V alpha regions. As has been previously reported, no bias was found in beta chain V region usage either. In addition to productive (in frame) TCR V region mRNAs in malignant cells from each patient, we detected non-productive (out of frame) beta chain transcripts in these cells in two of six patients, and non-productive alpha chain transcripts in five of six. Residual normal peripheral blood lymphocytes from these patients showed a random, polyclonal or oligoclonal pattern of V region usage. We conclude that there is no bias in V region usage in CTCL, making it unlikely that interactions between superantigen or virus and the TCR V regions play a role in the pathogenesis of CTCL.


Assuntos
Linfoma Cutâneo de Células T/imunologia , Receptores de Antígenos de Linfócitos T alfa-beta/genética , Linfócitos T/imunologia , Idoso , Idoso de 80 Anos ou mais , Sequência de Bases , Linfócitos T CD8-Positivos/imunologia , Humanos , Dados de Sequência Molecular , Reação em Cadeia da Polimerase , RNA Mensageiro/análise
12.
Hosp Pharm ; 30(7): 572-4, 577-8, 1995 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-10144212

RESUMO

All inpatients who were admitted to one designated cardiologist at a private community hospital were followed by a pharmacist. The pharmacist prospectively evaluated the patients' medications in order to identify, resolve, and prevent any medication related problems. Recommendations concerning these medication related problems were made to the physician involved. In addition, the pharmacist documented medication information questions, medication dosing consultations, and patient medication counseling consults. Ninety-seven percent of the recommendations were accepted by the prescriber. The most common categories of recommendations were for drugs belonging to cardiovascular (40.3%) and anti-infective (18.4%) classes. Improper medication selection (19.6%), untreated indication (17.4%), overdosage (16.3%), and medication given without an indication (13%) were the most common medication related problems and accounted for over two-thirds of the total accepted recommendations. Sixty-six percent of the recommendations were considered significant and 4% were considered extremely significant. Based on the pharmacist's interventions, an annual patient medication charge savings of $17,576.00 was estimated.


Assuntos
Doenças Cardiovasculares/tratamento farmacológico , Monitoramento de Medicamentos , Serviço de Farmácia Hospitalar , Doença Aguda , Custos de Medicamentos , Serviços de Informação sobre Medicamentos , Monitoramento de Medicamentos/economia , Tratamento Farmacológico/economia , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos , Georgia , Hospitais com mais de 500 Leitos , Hospitais Comunitários , Humanos , Erros de Medicação/classificação , Farmacêuticos , Serviço de Farmácia Hospitalar/economia , Estudos Prospectivos
13.
J Am Acad Dermatol ; 32(4): 545-61; quiz 562-4, 1995 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-7896943

RESUMO

Mast cell disease or mastocytosis is a heterogeneous group of clinical disorders characterized by the proliferation and accumulation of mast cells in a variety of tissues, most often the skin. The signs and symptoms of mast cell disease are varied, dependent on the localization of mast cells in different organs and the local and systemic effects of mediators released from these cells. Although mast cell disease is most commonly identified in the skin, involvement of the skeletal, hematopoietic, gastrointestinal, cardiopulmonary, and central nervous systems may be seen. Clinical management of mastocytosis depends most heavily on knowledge of the diverse effects of mast cell mediators on various tissues and organs, the stimuli that can cause their release, and the different methods available for blocking the effects of these mediators.


Assuntos
Mastócitos/fisiologia , Mastocitose , Doenças Ósseas/patologia , Dermatite Esfoliativa/patologia , Gastroenteropatias/patologia , Humanos , Mastocitose/classificação , Mastocitose/diagnóstico , Mastocitose/etiologia , Mastocitose/metabolismo , Mastocitose/patologia , Mastocitose/terapia , Urticaria Pigmentosa/patologia
14.
J Invest Dermatol ; 104(3): 329-34, 1995 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-7860996

RESUMO

I-E is a class II major histocompatibility complex molecule normally expressed by Langerhans cells. A series of transgenic mice were developed previously that carry E alpha d gene constructs with promoter-region deletions that cause expression of I-E by different cell types when maintained on a B6 (I-E[-]) genetic background. To study cis-acting gene sequences that regulate expression of class II proteins by Langerhans cells, we identified transgenic I-E expression by tissue immunoperoxidase staining and by epidermal cell suspension immunofluorescence cytometry. Mice with a transgene containing 1.4 kilobase pairs (kb) of flanking sequence 5' to the E alpha initiation site expressed barely detectable levels of I-E on a tiny percentage of Langerhans cells, indicating that sequences promoting Langerhans cell expression of E alpha exist between 2.0 and 1.4 kb 5' of the E alpha initiation site. Removal of an additional 170 bp of 5' flanking sequence caused near-normal levels of expression by approximately one third of epidermal Langerhans cells, which contrasts with studies that showed minimal transgene expression by splenic dendritic cells in these animals. Thus, sequences between 1.4 and 1.23 kb 5' of the E alpha initiation site decrease expression of I-E by epidermal Langerhans cells, but enable I-E expression by splenic dendritic cells. These studies identify Langerhans cell-specific regulatory sequences and genetic regions controlling major histocompatibility complex class II gene expression in Langerhans cells and splenic dendritic cells. The genetic regions identified may be particularly important because differential regulation of class II major histocompatibility complex protein synthesis by Langerhans cells and dendritic cells may be crucial to immune functions of intact animals.


Assuntos
Células de Langerhans/metabolismo , Animais , Antígenos de Superfície/genética , Células Dendríticas/metabolismo , Imunofluorescência , Regulação da Expressão Gênica , Genes MHC da Classe II , Genes Supressores , Camundongos , Camundongos Transgênicos , Baço/citologia , Timo/citologia
15.
J Invest Dermatol ; 104(1): 101-6, 1995 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-7528242

RESUMO

Mast cell growth factor (MGF), a molecule that serves as a ligand for the receptor tyrosine kinase c-kit, is important in mast cell differentiation, migration, and activation. Previous studies of paraffin-embedded human skin using antibody to murine MGF and reverse transcription-polymerase chain reaction have demonstrated MGF protein and mRNA expression in keratinocytes and isolated dermal cells. We utilized a monoclonal antibody to human MGF to further define patterns of immunoreactivity in frozen specimens of neonatal and adult skin from normal individuals and from patients with urticaria pigmentosa. In addition to keratinocytes and isolated dermal cells in normal and urticaria pigmentosa skin, MGF was detected in cells lining superficial and mid-dermal vessels. Co-expression of MGF and the vascular antigen CD31, and immunoelectron microscopy, identified MGF-positive cells as endothelial cells. Patterns of endothelial MGF expression were not influenced by mast cell degranulation and endothelial E-selectin induction in vitro. By ultrastructure, unfixed specimens demonstrated MGF expression both within the endothelial cytoplasm and in association with lumenal, but not ablumenal, surfaces. Specimens fixed with Nakane's solution had diminished endothelial cytoplasmic MGF reactivity, but lumenal expression was maintained, suggesting persistence of a membrane-associated reactivity. MGF mRNA was also detected in cultured dermal microvascular endothelial cells using reverse transcription-polymerase chain reaction. These data establish human dermal endothelial cells as sites of MGF production and expression in human skin. Mast cell precursors must home to skin via vascular channels and differentiate in the immediate perivascular space. Thus, endothelial MGF may be an important determinant of adhesion and differentiation of mast cell progenitors expressing receptors for MGF.


Assuntos
Fatores de Crescimento de Células Hematopoéticas/fisiologia , Pele/citologia , Adulto , Adesão Celular/fisiologia , Endotélio Vascular/química , Endotélio Vascular/citologia , Fatores de Crescimento de Células Hematopoéticas/genética , Humanos , Imuno-Histoquímica , Recém-Nascido , Masculino , Microcirculação/química , Microcirculação/citologia , Microscopia Imunoeletrônica , RNA Mensageiro/análise , Pele/química , Fator de Células-Tronco
16.
Am J Hosp Pharm ; 51(18): 2268-72, 1994 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-7801987

RESUMO

Factors associated with preventable adverse drug reactions (ADRs) in a community hospital patient population were studied. The following data were collected by concurrent review of all ADRs reported from July 1992 through January 1993: patient demographics, ADR variables, length of stay, and preventability of ADR. These data were analyzed to determine factors associated with preventable ADRs. Of the 203 ADRs reported, 38 (19%) were identified as preventable. The only significant difference found between preventable and nonpreventable ADRs was in severity (preventable ADRs were more severe). Length of stay (LOS) for patients who experienced ADRs was longer than the national average for patients in the same diagnosis-related group. Most of the preventable ADRs involved (1) a documented allergy to medication ordered or to similar medications, (2) anticoagulants or thrombolytics, (3) that required serum drug concentration monitoring (in the absence of pharmacokinetics service involvement), and (4) renally eliminated drugs for which dosage adjustments were not made in patients with impaired renal function. Strategies for minimizing ADRs were developed based on these factors. An ADR reporting program helped in identifying preventable ADRs, determining factors associated with preventable ADRs, and developing strategies for preventing ADRs in a community hospital patient population.


Assuntos
Sistemas de Notificação de Reações Adversas a Medicamentos/estatística & dados numéricos , Monitoramento de Medicamentos/estatística & dados numéricos , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos , Adolescente , Adulto , Sistemas de Notificação de Reações Adversas a Medicamentos/economia , Idoso , Criança , Pré-Escolar , Revisão Concomitante , Monitoramento de Medicamentos/economia , Feminino , Georgia , Hospitais Comunitários , Hospitais Privados , Humanos , Tempo de Internação , Masculino , Preparações Farmacêuticas/economia
18.
J Immunol ; 151(8): 3954-60, 1993 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-8409379

RESUMO

A variety of cell types expressing MHC class II molecules is known to function as APC in vitro. We employed the Ig kappa gene enhancer and promoter to target the class II E alpha gene, and thereby I-E, exclusively to B cells to address their APC function in vivo. Although transgenic I-E was expressed on B lymphocytes, we unexpectedly obtained I-E on thymic medullary epithelium but not macrophages and at low frequency on dendritic cells. Using these transgenic mice, we constructed bone marrow irradiation chimeras with I-E expressed only on medullary epithelium, in order to determine the role of this cell type in tolerance by clonal deletion in the thymus. Although it is accepted that bm-derived cells play a primary role in deletion, and thymic epithelium can delete clones to a lesser degree, the role of cortical vs medullary thymic epithelium has not been directly dissected. We demonstrate that medullary epithelium alone can tolerize by partial deletion of I-E-reactive V beta 5+ T cells. These results indicate a role for medullary epithelium in deletion during the later stages of thymic development, and support the notion that positive and negative selection of developing T cells can occur in distinct temporal and anatomic compartments.


Assuntos
Deleção Clonal , Antígenos de Histocompatibilidade Classe II/fisiologia , Receptores de Antígenos de Linfócitos T alfa-beta/análise , Linfócitos T/imunologia , Timo/fisiologia , Animais , Linfócitos B/imunologia , Elementos Facilitadores Genéticos , Genes de Imunoglobulinas , Cadeias kappa de Imunoglobulina/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos
19.
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