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2.
Infect Control Hosp Epidemiol ; 38(9): 1055-1061, 2017 09.
Artigo em Inglês | MEDLINE | ID: mdl-28724453

RESUMO

OBJECTIVE While a direct relation between hospital construction and concomitant infection rates has been clearly established, few data are available regarding the environmental decontamination effects of renovation in which surfaces are replaced and regarding subsequent infection incidence. DESIGN Retrospective clinical study with vancomycin-resistant Enterococcus (VRE) molecular strain typing and environmental cultures. SETTING A regional referral center for acute leukemia and hematopoietic stem-cell transplantation. PATIENTS Overall, 536 consecutive hospital admissions for newly diagnosed acute leukemia or a first autologous or allogeneic stem-cell transplantation were reviewed. INTERVENTION During 2009-2010, our unit underwent complete remodeling including replacement of all surfaces. We assessed the effects of this construction on the incidence of hospital-acquired VRE colonization before, during, and after the renovation. RESULTS We observed a sharp decrease in VRE colonization rates (hazard ratio, <0.23; 95% confidence interval, 0.18-0.44; P<.0001) during the first year after the renovation, with a return to near baseline rates thereafter. The known risk factors for VRE colonization appeared to be stable over the study interval. Environmental cultures outside of patient rooms revealed several contaminated areas that are commonly touched by unit personnel. Multilocus sequence typing of VRE isolates that were cryopreserved over the study interval showed that dominant strains prior to construction disappeared and were replaced by other strains after the renovation. CONCLUSIONS Unit reconstruction interrupted endemic transmission of VRE, which resumed with novel strains upon reopening. Contamination of environmental surfaces and shared equipment may play an important role in endemic transmission of VRE. Infect Control Hosp Epidemiol 2017;38:1055-1061.


Assuntos
Infecção Hospitalar/epidemiologia , Infecção Hospitalar/microbiologia , Infecções por Bactérias Gram-Positivas/epidemiologia , Infecções por Bactérias Gram-Positivas/etiologia , Enterococos Resistentes à Vancomicina/isolamento & purificação , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Antibacterianos , Contaminação de Equipamentos/prevenção & controle , Feminino , Neoplasias Hematológicas , Transplante de Células-Tronco Hematopoéticas , Arquitetura Hospitalar , Humanos , Controle de Infecções/métodos , Leucemia Mieloide Aguda , Masculino , Pessoa de Meia-Idade , Tipagem Molecular , Quartos de Pacientes , Modelos de Riscos Proporcionais , Estudos Retrospectivos , Vancomicina , Resistência a Vancomicina , Enterococos Resistentes à Vancomicina/patogenicidade , Adulto Jovem
3.
Am J Med ; 130(1): 47-53, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27619354

RESUMO

BACKGROUND: Overuse of clinical laboratory testing in the inpatient setting is a common problem. The objective of this project was to develop an inexpensive and easily implemented intervention to promote rational laboratory use without compromising resident education or patient care. METHODS: The study comprised of a cluster-randomized, controlled trial to assess the impact of a multifaceted intervention of education, guideline development, elimination of recurring laboratory orders, unbundling of laboratory panels, and redesign of the daily progress note on laboratory test ordering. The population included all patients hospitalized "general medicine" was duplicated during 2 consecutive months on a general medicine teaching service within a 999-bed tertiary care hospital in Boston, Massachusetts. The primary outcome was the total number of commonly used laboratory tests per patient day during 2 months in 2008. Secondary outcomes included a subgroup analysis of each individual test per patient day, adverse events, and resident and nursing satisfaction. RESULTS: A total of 5392 patient days were captured. The intervention produced a 9% decrease in aggregate laboratory use (rate ratio, 0.91; P = .021; 95% confidence interval, 0.84-0.98). Six instances of delayed diagnosis of acute kidney injury and 11 near misses were reported in the intervention arm. CONCLUSIONS: A bundled educational and administrative intervention promoting rational ordering of laboratory tests on a single academic general medicine service led to a modest but significant decrease in laboratory use. To our knowledge, this was the first study to examine the daily progress note as a tool to limit excessive test ordering. Unadjudicated near misses and possible harm were reported with this intervention. This finding warrants further study.


Assuntos
Centros Médicos Acadêmicos/métodos , Técnicas de Laboratório Clínico/métodos , Capacitação em Serviço/métodos , Procedimentos Desnecessários/estatística & dados numéricos , Centros Médicos Acadêmicos/organização & administração , Boston , Feminino , Humanos , Masculino , Sistemas de Registro de Ordens Médicas/organização & administração , Sistemas de Registro de Ordens Médicas/estatística & dados numéricos , Pessoa de Meia-Idade , Política Organizacional , Centros de Atenção Terciária/organização & administração
4.
J Geriatr Oncol ; 6(4): 288-98, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-26073533

RESUMO

OBJECTIVES: The International Prognostic Scoring System (IPSS) is commonly used to predict survival and assign treatment for the myelodysplastic syndromes (MDS). We explored whether self-reported and readily available non-hematologic predictors of survival add independent prognostic information to the IPSS. MATERIALS AND METHODS: Retrospective cohort study of consecutive MDS patients ≥age 65 who presented to Dana-Farber Cancer Institute between 2006 and 2011 and completed a baseline quality of life questionnaire. Questions corresponding to functional status and symptoms and extracted clinical-pathologic data from medical records. Kaplan-Meier and Cox proportional hazards models were used to estimate survival. RESULTS: One hundred fourteen patients consented and were available for analysis. Median age was 73 years, and the majority of patients were White, were male, and had a Charlson comorbidity score of <2. Few patients (24%) had an IPSS score consistent with lower-risk disease and the majority received chemotherapy. In addition to IPSS score and history of prior chemotherapy or radiation, significant univariate predictors of survival included low serum albumin, Charlson score, performance status, ability to take a long walk, and interference of physical symptoms in family life. The multivariate model that best predicted mortality included low serum albumin (HR=2.3; 95% CI: 1.06-5.14), therapy-related MDS (HR=2.1; 95% CI: 1.16-4.24), IPSS score (HR=1.7; 95% CI: 1.14-2.49), and ease taking a long walk (HR=0.44; 95% CI: 0.23-0.90). CONCLUSIONS: In this study of older adults with MDS, we found that low serum albumin and physical function added important prognostic information to the IPSS score. Self-reported physical function was more predictive than physician-assigned performance status.


Assuntos
Avaliação Geriátrica/estatística & dados numéricos , Síndromes Mielodisplásicas/diagnóstico , Síndromes Mielodisplásicas/mortalidade , Inquéritos e Questionários , Idoso , Idoso de 80 Anos ou mais , Estudos de Coortes , Comorbidade , Feminino , Avaliação Geriátrica/métodos , Humanos , Masculino , Prognóstico , Modelos de Riscos Proporcionais , Estudos Retrospectivos , Fatores de Risco , Autorrelato , Análise de Sobrevida
5.
Blood ; 123(18): 2816-25, 2014 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-24574459

RESUMO

Our previous studies revealed an increase in alternative splicing of multiple RNAs in cells from patients with acute myeloid leukemia (AML) compared with CD34(+) bone marrow cells from normal donors. Aberrantly spliced genes included a number of oncogenes, tumor suppressor genes, and genes involved in regulation of apoptosis, cell cycle, and cell differentiation. Among the most commonly mis-spliced genes (>70% of AML patients) were 2, NOTCH2 and FLT3, that encode myeloid cell surface proteins. The splice variants of NOTCH2 and FLT3 resulted from complete or partial exon skipping and utilization of cryptic splice sites. Longitudinal analyses suggested that NOTCH2 and FLT3 aberrant splicing correlated with disease status. Correlation analyses between splice variants of these genes and clinical features of patients showed an association between NOTCH2-Va splice variant and overall survival of patients. Our results suggest that NOTCH2 and FLT3 mis-splicing is a common characteristic of AML and has the potential to generate transcripts encoding proteins with altered function. Thus, splice variants of these genes might provide disease markers and targets for novel therapeutics.


Assuntos
Processamento Alternativo , Leucemia Mieloide Aguda/genética , Receptor Notch2/genética , Tirosina Quinase 3 Semelhante a fms/genética , Linhagem Celular , Análise por Conglomerados , Perfilação da Expressão Gênica , Regulação Leucêmica da Expressão Gênica , Humanos , Leucemia Mieloide Aguda/diagnóstico , Leucemia Mieloide Aguda/tratamento farmacológico , Leucemia Mieloide Aguda/metabolismo , Leucemia Mieloide Aguda/mortalidade , Proteínas de Membrana/metabolismo , Prognóstico , Receptor Notch2/metabolismo , Ativação Transcricional , Resultado do Tratamento , Tirosina Quinase 3 Semelhante a fms/metabolismo
6.
Clin Cancer Res ; 20(5): 1135-45, 2014 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-24284058

RESUMO

PURPOSE: Despite new treatments, acute myeloid leukemia (AML) remains an incurable disease. More effective drug design requires an expanded view of the molecular complexity that underlies AML. Alternative splicing of RNA is used by normal cells to generate protein diversity. Growing evidence indicates that aberrant splicing of genes plays a key role in cancer. We investigated genome-wide splicing abnormalities in AML and based on these abnormalities, we aimed to identify novel potential biomarkers and therapeutic targets. EXPERIMENTAL DESIGN: We used genome-wide alternative splicing screening to investigate alternative splicing abnormalities in two independent AML patient cohorts [Dana-Farber Cancer Institute (DFCI) (Boston, MA) and University Hospital de Nantes (UHN) (Nantes, France)] and normal donors. Selected splicing events were confirmed through cloning and sequencing analysis, and than validated in 193 patients with AML. RESULTS: Our results show that approximately 29% of expressed genes genome-wide were differentially and recurrently spliced in patients with AML compared with normal donors bone marrow CD34(+) cells. Results were reproducible in two independent AML cohorts. In both cohorts, annotation analyses indicated similar proportions of differentially spliced genes encoding several oncogenes, tumor suppressor proteins, splicing factors, and heterogeneous-nuclear-ribonucleoproteins, proteins involved in apoptosis, cell proliferation, and spliceosome assembly. Our findings are consistent with reports for other malignances and indicate that AML-specific aberrations in splicing mechanisms are a hallmark of AML pathogenesis. CONCLUSIONS: Overall, our results suggest that aberrant splicing is a common characteristic for AML. Our findings also suggest that splice variant transcripts that are the result of splicing aberrations create novel disease markers and provide potential targets for small molecules or antibody therapeutics for this disease.


Assuntos
Estudo de Associação Genômica Ampla , Leucemia Mieloide Aguda/genética , Splicing de RNA , Processamento Alternativo , Biomarcadores Tumorais , Antígenos CD13/genética , Perfilação da Expressão Gênica , Frequência do Gene , Humanos , Leucemia Mieloide Aguda/tratamento farmacológico , Leucemia Mieloide Aguda/metabolismo , Anotação de Sequência Molecular , Terapia de Alvo Molecular , Reprodutibilidade dos Testes , Transdução de Sinais
7.
Leuk Res ; 37(9): 998-1003, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23747082

RESUMO

We explored whether geriatric assessment variables predicted mortality in addition to known prognostic factors in 101 patients aged ≥ 65 with newly diagnosed AML. Baseline comorbidity score (HR=1.92; 95%CI 1.18-3.11), difficulty with strenuous activity (HR=2.18; 95%CI 1.19-4.00), and pain (HR=2.17; 95%CI 1.19-3.97) were independent prognostic factors for greater risk of death in a multivariable model that included cytogenetic risk group. They remained independent predictors in the subset of patients with baseline ECOG PS 0-1. Our results support the use of geriatric assessment to better predict prognosis in older patients with AML, even among those with excellent functional status.


Assuntos
Avaliação Geriátrica , Leucemia Mieloide Aguda/mortalidade , Leucemia Mieloide Aguda/terapia , Qualidade de Vida , Idoso , Idoso de 80 Anos ou mais , Comorbidade , Feminino , Seguimentos , Humanos , Masculino , Prognóstico , Estudos Prospectivos , Estudos Retrospectivos , Taxa de Sobrevida
8.
Hematol Oncol Clin North Am ; 26(2): 395-408, ix, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22463834

RESUMO

Lymph node or spleen enlargement may be innocent or the first sign of a serious disorder. Lymphadenopathy and splenomegaly can be found in symptomatic or asymptomatic patients. Lymph node enlargement in a single region or multiple sites can be seen in various diseases, including infections, noninfectious inflammatory conditions, or malignancies; a similar differential diagnosis applies to splenomegaly, but splenomegaly can also be caused by vascular abnormalities and hemolysis. Frequently, lymphadenopathy is detected incidentally during screening examinations or imaging procedures. This review focuses on causes of lymphadenopathy and splenomegaly and an appropriate diagnostic approach to patients with lymphadenopathy or splenomegaly.


Assuntos
Doenças Linfáticas/etiologia , Esplenomegalia/etiologia , Biópsia , Humanos , Linfonodos/patologia , Doenças Linfáticas/diagnóstico , Esplenectomia , Esplenomegalia/diagnóstico , Esplenomegalia/terapia
9.
Curr Treat Options Oncol ; 12(4): 341-53, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21901552

RESUMO

OPINION STATEMENT: Older patients with acute myelogenous leukemia (AML) fare much less well than younger patients with the same disease due to a combination of comorbidities and intrinsic disease resistance. Likely due to aging of the US population, the median age of AML patients at diagnosis has increased from 68 to 72 years. AML is a heterogeneous disease, particularly in older patients, making therapeutic decisions challenging. Older patients who are 'fit' for intensive chemotherapy and would have a reasonable chance to benefit based on host and disease characteristics should receive standard induction chemotherapy with 7 days of continuous infusion of cytarabine and at least 60 mg/m(2) daunorubicin daily for 3 days. Therapeutic options for patients who are not candidates for or are not likely to respond to intensive therapy include clofarabine, low intensity chemotherapy such as low dose cytarabine, hypomethylating agents, or investigational agents. For older AML patients in complete remission, post-remission or consolidation chemotherapy with repeat induction or modified high dose cytarabine may offer a small chance for long term disease-free survival. Selected older patients who achieve remission by any means should be considered for reduced-intensity stem cell transplantation which may offer improved chances of cure and survival compared with standard post-remission chemotherapy.


Assuntos
Leucemia Mieloide Aguda/terapia , Idoso , Idoso de 80 Anos ou mais , Biomarcadores Tumorais/genética , Aberrações Cromossômicas , Quimioterapia de Consolidação , Transplante de Células-Tronco Hematopoéticas , Humanos , Quimioterapia de Indução , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/mortalidade , Prognóstico , Resultado do Tratamento
10.
Am J Hematol ; 86(6): 500-2, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21594887

RESUMO

Cryoglobulins are immunoglobulins that precipitate below 37°C and can cause multiorgan damage. There are three types of cryoglobulins: Type I (also called simple), which is mostly associated with monoclonal gammopathy and/or other hematologic disorders and Type II and Type III (known as mixed cryoglobulins), which are associated with infectious and systemic diseases. Testing for cryoglobulins is complicated by lack of reference range, standards, and stringency in maintaining testing temperature conditions. Identification of cryoprecipitate can be critical for patient care; therefore, correct testing conditions are crucial for reliable cryoglobulin testing. The patient's blood sample should be kept at 37°C initially to avoid premature precipitation of cryoglobulins and thereby decreasing the yield for subsequent identification. This could cause a false negative result. After warm centrifugation or warm cell precipitation, the clear serum is observed at 4°C for formation of cryoprecipitate. The cryoprecipitate is then washed in cold buffer, and the resulting precipitate is warmed to 37°C and subjected to further analysis by immunodiffusion and immunofixation. In addition to Meltzer's triad of purpura, weakness and arthralgias, cryoglobulinemias have protean manifestations involving skin, joints, kidney, nervous system, as well as the hematopoietic system. The management of cryoglobulinemia especially in patients with organ damage remains difficult. Treatment of cryoglobulinemia focuses on management of the underlying lymphoproliferative disorder or infectious or systemic causes. Medical management may also include corticosteroids and other immunosuppressive agents and plasmapheresis. Rituximab therapy seems to abrogate the aberrant B cell response.


Assuntos
Crioglobulinemia/diagnóstico , Crioglobulinemia/terapia , Crioglobulinas/análise , Técnicas de Laboratório Clínico , Gerenciamento Clínico , Humanos , Guias de Prática Clínica como Assunto
11.
Curr Hematol Malig Rep ; 5(2): 109-17, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-20425404

RESUMO

The prognosis for patients with acute myelogenous leukemia (AML) is dependent on age, karyotype, and the genetics of the neoplastic cell. The molecular markers with prognostic impact include mutations in FLT3, NPM1, MLL, WT1, c-KIT, and expression levels of BAALC, NM1, ERG, and CXCR4. Gene expression profiles and microRNA expression patterns in AML may prove highly useful in defining the prognosis of AML. Cytogenetic and, increasingly, molecular findings are used in determining the best therapy for AML patients, especially the choice of whether to perform allogeneic stem cell transplantation.


Assuntos
Biomarcadores Tumorais/genética , Perfilação da Expressão Gênica , Leucemia Mieloide/genética , Doença Aguda , Humanos , Cariotipagem , Leucemia Mieloide/diagnóstico , Leucemia Mieloide/terapia , MicroRNAs/genética , Mutação , Nucleofosmina , Prognóstico
12.
Leuk Lymphoma ; 51(5): 789-96, 2010 May.
Artigo em Inglês | MEDLINE | ID: mdl-20367136

RESUMO

Autologous stem cell transplant (ASCT) is the standard of care for patients with relapsed diffuse large B-cell lymphoma (DLBCL). Adding rituximab (R) to the initial therapy has improved outcomes; however, the benefit of ASCT for chemosensitive patients who fail R-CHOP (rituximab, cyclophosphamide, adriamycin, vincristine, prednisone) is unclear. Patients who underwent ASCT between 1997 and 2006 for DLBCL at two partner institutions were identified. Characteristics and outcomes were compared between patients who received R-CHOP as initial chemotherapy and those who received CHOP. Of the 185 patients evaluated, 137 were initially treated with CHOP and 48 received R-CHOP. Patients who received R-CHOP were older, had shorter remissions, and initially had more advanced stage. With univariate analysis, PFS and OS did not differ; however, multivariable Cox regression analysis suggested a poorer prognosis for patients who underwent ASCT after failing R-CHOP. In conclusion, patients who fail R-CHOP appear to benefit from ASCT, but they may have a worse prognosis compared to patients who fail CHOP alone.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Linfoma Difuso de Grandes Células B/terapia , Recidiva Local de Neoplasia/terapia , Transplante de Células-Tronco , Adolescente , Adulto , Idoso , Anticorpos Monoclonais/administração & dosagem , Anticorpos Monoclonais Murinos , Estudos de Coortes , Ciclofosfamida/administração & dosagem , Doxorrubicina/administração & dosagem , Feminino , Humanos , Linfoma Difuso de Grandes Células B/patologia , Masculino , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/patologia , Prednisona/administração & dosagem , Estudos Retrospectivos , Rituximab , Taxa de Sobrevida , Transplante Autólogo , Falha de Tratamento , Resultado do Tratamento , Vincristina/administração & dosagem , Adulto Jovem
13.
Mol Immunol ; 43(7): 773-82, 2006 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-16095699

RESUMO

Elucidating the role of glucocorticoid in regulating gene expression is crucial to developing effective strategies against inflammatory diseases such as arthritis. In this report we demonstrate that glucocorticoid inhibits transcription directed by the IL-lbeta gene (IL1B) upstream induction sequence (UIS) enhancer, and to a much lesser extent by the tissue-specific basal promoter. Within the enhancer, three transcription factor binding sites, previously demonstrated by us to be important for the induction of IL1B by lipopolysaccharide, are now shown to be directly inhibited by the synthetic glucocorticoid, dexamethasone. We also previously showed that one of these sites could bind a novel STAT-like factor, while the other two bound heterodimers containing NF-IL6(C/EBPbeta). Although it has been reported by others that NF-IL6 homodimers can interact with glucocorticoid receptor (GR) to enhance transcription of the alpha1-acid glycoprotein gene, it now appears that glucocorticoid represses DNA binding of NF-IL6 heterodimers as well as the novel STAT-like factor to the critical sites within the IL1B UIS. Thus, GR likely disrupts the DNA binding capability of critical IL1B factors via transrepression.


Assuntos
Dexametasona/farmacologia , Elementos Facilitadores Genéticos , Regulação da Expressão Gênica/efeitos dos fármacos , Interleucina-1/genética , Precursores de Proteínas/genética , Transativadores/antagonistas & inibidores , Sítios de Ligação , Proteína delta de Ligação ao Facilitador CCAAT/antagonistas & inibidores , Proteína delta de Ligação ao Facilitador CCAAT/metabolismo , Células Cultivadas , Cloranfenicol O-Acetiltransferase/análise , Cloranfenicol O-Acetiltransferase/genética , DNA/metabolismo , Glucocorticoides/farmacologia , Humanos , Lipopolissacarídeos/farmacologia , RNA Mensageiro/análise , RNA Mensageiro/metabolismo , Transdução de Sinais , Transativadores/metabolismo
14.
Proc Natl Acad Sci U S A ; 100(10): 6051-6, 2003 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-12719541

RESUMO

MITF, TFE3, TFEB, and TFEC comprise a transcription factor family (MiT) that regulates key developmental pathways in several cell lineages. Like MYC, MiT members are basic helix-loop-helix-leucine zipper transcription factors. MiT members share virtually perfect homology in their DNA binding domains and bind a common DNA motif. Translocations of TFE3 occur in specific subsets of human renal cell carcinomas and in alveolar soft part sarcomas. Although multiple translocation partners are fused to TFE3, each translocation product retains TFE3's basic helix-loop-helix leucine zipper. We have identified the genes fused by the chromosomal translocation t(6;11)(p21.1;q13), characteristic of another subset of renal neoplasms. In two primary tumors we found that Alpha, an intronless gene, rearranges with the first intron of TFEB, just upstream of TFEB's initiation ATG, preserving the entire TFEB coding sequence. Fluorescence in situ hybridization confirmed the involvement of both TFEB and Alpha in this translocation. Although the Alpha promoter drives expression of this fusion gene, the Alpha gene does not contribute to the ORF. Whereas TFE3 is typically fused to partner proteins in subsets of renal tumors, we found that wild-type, unfused TFE3 stimulates clonogenic growth in a cell-based assay, suggesting that dysregulated expression, rather than altered function of TFEB or TFE3 fusions, may confer neoplastic properties, a mechanism reminiscent of MYC activation by promoter substitution in Burkitt's lymphoma. Alpha-TFEB is thus identified as a fusion gene in a subset of pediatric renal neoplasms.


Assuntos
Cromossomos Humanos Par 11 , Cromossomos Humanos Par 6 , Proteínas de Ligação a DNA/genética , Neoplasias Renais/genética , Proteínas de Neoplasias , Translocação Genética , Sequência de Bases , Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos , Mapeamento Cromossômico , Clonagem Molecular , Primers do DNA , Rearranjo Gênico , Sequências Hélice-Alça-Hélice , Humanos , Íntrons , Neoplasias Renais/patologia , Dados de Sequência Molecular , Proteínas de Fusão Oncogênica/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fatores de Transcrição/genética , Ensaio Tumoral de Célula-Tronco
15.
Curr Mol Med ; 2(5): 407-21, 2002 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-12125807

RESUMO

Patients with pycnodysostosis, a rare skeletal dysplasia, present with bone abnormalities such as short stature, acroosteolysis of distal phalanges, and skull deformities. The disease is caused by a deficiency of the cysteine protease cathepsin K which is responsible for degradation of collagen type I and other bone proteins. Osteoclasts, bone cells of hematopoietic origin responsible for bone mineral as well as protein matrix degradation, are dysfunctional in patients with pycnodysostosis due to mutations in the cathepsin K gene. Cathepsin K deficient osteoclasts can demineralize bone but cannot degrade the protein matrix. Mutations in the cathepsin K gene disrupting wild type cathepsin K activity have been described in patients with pycnodysostosis. Animal models of cathepsin K deficiency have been created and provide a valuable tool to study osteoclast function and treatment for cathepsin K deficiency. Understanding the regulation and role of cathepsin K in osteoclast function is important for designing future therapies for pycnodysostosis. Cathepsin K inhibitors will be useful in pathological processes involving excess osteoclast activation and bone resorption such as osteoporosis, bone metastasis and multiple myeloma. This review will discuss the bone remodeling cycle, the human disease pycnodysostosis caused by cathepsin K deficiency and cathepsin K activity and regulation.


Assuntos
Catepsinas/fisiologia , Doenças por Armazenamento dos Lisossomos/genética , Osteocondrodisplasias/metabolismo , Osteoclastos/metabolismo , Osso e Ossos/fisiologia , Catepsina K , Catepsinas/deficiência , Catepsinas/genética , Humanos , Concentração de Íons de Hidrogênio , Doenças por Armazenamento dos Lisossomos/enzimologia , Modelos Biológicos , Modelos Genéticos , Mutação , Osteocondrodisplasias/genética , Osteocondrodisplasias/patologia , Osteopetrose/patologia
16.
Cell ; 109(6): 707-18, 2002 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-12086670

RESUMO

Kit/SCF signaling and Mitf-dependent transcription are both essential for melanocyte development and pigmentation. To identify Mitf-dependent Kit transcriptional targets in primary melanocytes, microarray studies were undertaken. Among identified targets was BCL2, whose germline deletion produces melanocyte loss and which exhibited phenotypic synergy with Mitf in mice. BCL2's regulation by Mitf was verified in melanocytes and melanoma cells and by chromatin immunoprecipitation of the BCL2 promoter. Mitf also regulates BCL2 in osteoclasts, and both Mitf(mi/mi) and Bcl2(-/-) mice exhibit severe osteopetrosis. Disruption of Mitf in melanocytes or melanoma triggered profound apoptosis susceptible to rescue by BCL2 overexpression. Clinically, primary human melanoma expression microarrays revealed tight nearest neighbor linkage for MITF and BCL2. This linkage helps explain the vital roles of both Mitf and Bcl2 in the melanocyte lineage and the well-known treatment resistance of melanoma.


Assuntos
Proteínas de Ligação a DNA/metabolismo , Melanócitos/metabolismo , Melanoma/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Fatores de Transcrição , Adenoviridae/metabolismo , Animais , Linhagem da Célula , Separação Celular , Sobrevivência Celular , Cromatina/metabolismo , Cicloeximida/farmacologia , Citometria de Fluxo , Regulação da Expressão Gênica , Humanos , Camundongos , Fator de Transcrição Associado à Microftalmia , Modelos Genéticos , Análise de Sequência com Séries de Oligonucleotídeos , Osteoblastos/metabolismo , Osteoclastos/metabolismo , Osteopetrose/metabolismo , Fenótipo , Fosforilação , Regiões Promotoras Genéticas , Ligação Proteica , Inibidores da Síntese de Proteínas/farmacologia , Proteínas Proto-Oncogênicas c-bcl-2/genética , Transdução de Sinais , Baço/citologia , Fatores de Tempo , Transcrição Gênica , Células Tumorais Cultivadas
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