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1.
AJNR Am J Neuroradiol ; 43(8): 1115-1123, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-36920774

RESUMO

BACKGROUND AND PURPOSE: Glioblastoma is an aggressive brain tumor, with no validated prognostic biomarkers for survival before surgical resection. Although recent approaches have demonstrated the prognostic ability of tumor habitat (constituting necrotic core, enhancing lesion, T2/FLAIR hyperintensity subcompartments) derived radiomic features for glioblastoma survival on treatment-naive MR imaging scans, radiomic features are known to be sensitive to MR imaging acquisitions across sites and scanners. In this study, we sought to identify the radiomic features that are both stable across sites and discriminatory of poor and improved progression-free survival in glioblastoma tumors. MATERIALS AND METHODS: We used 150 treatment-naive glioblastoma MR imaging scans (Gadolinium-T1w, T2w, FLAIR) obtained from 5 sites. For every tumor subcompartment (enhancing tumor, peritumoral FLAIR-hyperintensities, necrosis), a total of 316 three-dimensional radiomic features were extracted. The training cohort constituted studies from 4 sites (n = 93) to select the most stable and discriminatory radiomic features for every tumor subcompartment. These features were used on a hold-out cohort (n = 57) to evaluate their ability to discriminate patients with poor survival from those with improved survival. RESULTS: Incorporating the most stable and discriminatory features within a linear discriminant analysis classifier yielded areas under the curve of 0.71, 0.73, and 0.76 on the test set for distinguishing poor and improved survival compared with discriminatory features alone (areas under the curve of 0.65, 0.54, 0.62) from the necrotic core, enhancing tumor, and peritumoral T2/FLAIR hyperintensity, respectively. CONCLUSIONS: Incorporating stable and discriminatory radiomic features extracted from tumors and associated habitats across multisite MR imaging sequences may yield robust prognostic classifiers of patient survival in glioblastoma tumors.


Assuntos
Neoplasias Encefálicas , Glioblastoma , Humanos , Glioblastoma/patologia , Intervalo Livre de Progressão , Estudos Retrospectivos , Neoplasias Encefálicas/patologia , Prognóstico , Imageamento por Ressonância Magnética/métodos
3.
Ann Oncol ; 29(2): 497-503, 2018 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-29161348

RESUMO

Background: In this study, we use a competing risks analysis to assess factors predictive of early-salvage whole brain radiotherapy (WBRT) and early death after upfront stereotactic radiosurgery (SRS) alone for brain metastases in an attempt to identify populations that benefit less from upfront SRS. Patients and methods: Patients from eight academic centers were treated with SRS for brain metastasis. Competing risks analysis was carried out for distant brain failure (DBF) versus death prior to DBF as well as for salvage SRS versus salvage WBRT versus death prior to salvage. Linear regression was used to determine predictors of the number of brain metastases at initial DBF (nDBF). Results: A total of 2657 patients were treated with upfront SRS alone. Multivariate analysis (MVA) identified an increased hazard of DBF associated with increasing number of brain metastases (P < 0.001), lowest SRS dose received (P < 0.001), and melanoma histology (P < 0.001), while there was a decreased hazard of DBF associated with increasing age (P < 0.001), KPS < 70 (P < 0.001), and progressive systemic disease (P = 0.004). MVA for first salvage SRS versus WBRT versus death prior to salvage revealed an increased hazard of first salvage WBRT seen with increasing number of brain metastases (P < 0.001) and a decreased hazard with widespread systemic disease (P = 0.002) and increasing age (P < 0.001). Variables associated with nDBF included age (P = 0.02), systemic disease status (P = 0.03), melanoma histology (P = 0.05), and initial number of brain metastases (P < 0.001). Conclusions: Patients with a higher initial number of brain metastases were more likely to experience DBF, have a higher nDBF, and receive early-salvage WBRT, while patients who were older, had lower KPS, or had more systemic disease were more likely to experience death prior to DBF or salvage WBRT.


Assuntos
Neoplasias Encefálicas/radioterapia , Neoplasias Encefálicas/secundário , Radiocirurgia/mortalidade , Adulto , Idoso , Neoplasias Encefálicas/mortalidade , Feminino , Humanos , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Fatores de Risco , Terapia de Salvação
4.
Cardiooncology ; 2(1): 6, 2016 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-33530138

RESUMO

BACKGROUND: Electrocardiographic changes may manifest in patients with pericardial effusions. PR segment changes are frequently overlooked, but when present, can provide diagnostic significance. The diagnostic value of PR segment changes in determining benign versus malignant pericardial disease in cancer patients with pericardial effusions has not been investigated. We aimed to determine the relationship between PR segment changes and malignant pericardial disease in cancer patients presenting with pericardial effusions. METHODS: Consecutive patients with active malignancy who underwent surgical subxiphoid pericardial window by a single thoracic surgeon between 2011 and 2014 were included in this study. A total of 104 pre- and post-operative ECGs were reviewed, and PR depression or elevation was defined by deviation of at least 0.5 millivolts from the TP segment using a magnifying glass. Pericardial fluid cytology, flow cytometry and tissue biopsy were evaluated. Baseline characteristics and co-morbidities were compared between cancer patients with benign and malignant pericardial effusions. RESULTS: A total of 26 patients with active malignancy and pericardial effusion who underwent pericardial window over the study period were included. Eighteen (69 %) patients had isoelectric PR segments, of whom none (0 %) had evidence of malignant pericardial disease (100 % negative predictive value). Eight (31 %) patients had significant ECG findings (PR segment depression in leads II, III and/or aVF as well as PR elevation in aVR/V1), all 8 (100 %) of whom had pathologically confirmed malignant pericardial disease (100 % positive predictive value). PR segment changes in all 8 patients persisted (up to 11 months) on post-operative serial ECGs. The PR segment changes had no relationship to heart rate or the time of atrial-ventricular conduction. CONCLUSIONS: In patients with active cancer presenting with pericardial effusion, the presence of PR segment changes is highly predictive of active malignant pericardial disease. When present, PR changes typically persist on serial ECGs even after pericardial window.

5.
J Thromb Haemost ; 13(6): 1103-12, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25851510

RESUMO

BACKGROUND: Anagrelide is a cytoreductive agent used to lower platelet counts in essential thrombocythemia. Although the drug has been known to selectively inhibit megakaryopoiesis for many years, the molecular mechanism accounting for this activity is still unclear. OBJECTIVES AND METHODS: To address this issue we have compared the global gene expression profiles of human hematopoietic cells treated ex-vivo with and without anagrelide while growing under megakaryocyte differentiation conditions, using high-density oligonucleotide microarrays. Gene expression data were validated by the quantitative polymerase chain reaction and mined to identify functional subsets and regulatory pathways. RESULTS: We identified 328 annotated genes differentially regulated by anagrelide, including many genes associated with platelet functions and with the control of gene transcription. Prominent among the latter was TRIB3, whose expression increased in the presence of anagrelide. Pathway analysis revealed that anagrelide up-regulated genes that are under the control of the transcription factor ATF4, a known TRIB3 inducer. Notably, immunoblot analysis demonstrated that anagrelide induced the phosphorylation of eIF2α, which is an upstream regulator of ATF4, and increased ATF4 protein levels. Furthermore, salubrinal, an inhibitor of eIF2α dephosphorylation, increased the expression of ATF4-regulated genes and blocked megakaryocyte growth. CONCLUSIONS: These findings link signaling through eIF2α/ATF4 to the anti-megakaryopoietic activity of anagrelide and identify new potential modulators of megakaryopoiesis.


Assuntos
Perfilação da Expressão Gênica , Fármacos Hematológicos/farmacologia , Megacariócitos/efeitos dos fármacos , Quinazolinas/farmacologia , Trombopoese/efeitos dos fármacos , Fator 4 Ativador da Transcrição/genética , Fator 4 Ativador da Transcrição/metabolismo , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Proliferação de Células , Células Cultivadas , Biologia Computacional , Bases de Dados Genéticas , Fator de Iniciação 2 em Eucariotos/genética , Fator de Iniciação 2 em Eucariotos/metabolismo , Perfilação da Expressão Gênica/métodos , Regulação da Expressão Gênica , Redes Reguladoras de Genes , Humanos , Megacariócitos/metabolismo , Análise de Sequência com Séries de Oligonucleotídeos , Fosforilação , Reação em Cadeia da Polimerase , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Repressoras/genética , Proteínas Repressoras/metabolismo , Transdução de Sinais , Trombopoese/genética , Fatores de Tempo
7.
Bone Marrow Transplant ; 46(6): 876-9, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20871638

RESUMO

Pneumatosis intestinalis (PI) occurs when gastrointestinal (GI) wall disruption, increased wall permeability or necrosis leads to wall infiltration by gas. It is associated with a spectrum of causal factors, including GI disease in allogeneic blood and marrow transplant patients. Traditionally, PI has been managed surgically with high morbidity and mortality. We describe our experience managing allogeneic blood and marrow transplant patients with PI. From January 1998 to May 2008, 320 patients underwent allogeneic blood and marrow transplant of whom 10 were identified with PI. PI diagnosis was established by computed tomography scan (n=7), plain film (n=2) or colonoscopy (n=1). A total of 9 of 10 patients had ongoing GI GvHD or received recent treatment for GI GvHD. Before April 2002, two patients underwent subtotal colectomy with ileostomy (n=1) and sigmoid colectomy with colostomy (n=1). One patient was managed with bowel rest and total parental nutrition (TPN) only. These three patients died 0.4, 1.1 and 3.9 years after PI diagnosis owing to GI GvHD (n=2) and surgical complications (n=1). Seven patients, diagnosed after September 2006, were treated with GI rest, TPN and antibiotics. PI treated with GI rest, TPN and antibiotics will resolve without surgical intervention. AlloBMT-associated PI is often a non-critical finding that does not represent true GI tract ischemia and/or GI tract perforation.


Assuntos
Transplante de Medula Óssea/efeitos adversos , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Pneumatose Cistoide Intestinal/terapia , Adulto , Antibacterianos , Gerenciamento Clínico , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Nutrição Parenteral , Pneumatose Cistoide Intestinal/etiologia , Estudos Retrospectivos , Transplante Homólogo , Resultado do Tratamento
8.
J Thromb Haemost ; 8(10): 2252-61, 2010 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-20586925

RESUMO

BACKGROUND: Anagrelide is a selective inhibitor of megakaryocytopoiesis used to treat thrombocytosis in patients with chronic myeloproliferative disorders. The effectiveness of anagrelide in lowering platelet counts is firmly established, but its primary mechanism of action remains elusive. OBJECTIVES AND METHODS: Here, we have evaluated whether anagrelide interferes with the major signal transduction cascades stimulated by thrombopoietin in the hematopoietic cell line UT-7/mpl and in cultured CD34(+) -derived human hematopoietic cells. In addition, we have used quantitative mRNA expression analysis to assess whether the drug affects the levels of known transcription factors that control megakaryocytopoiesis. RESULTS: In UT-7/mpl cells, anagrelide (1µm) did not interfere with MPL-mediated signaling as monitored by its lack of effect on JAK2 phosphorylation. Similarly, the drug did not affect the phosphorylation of STAT3, ERK1/2 or AKT in either UT-7/mpl cells or primary hematopoietic cells. In contrast, during thrombopoietin-induced megakaryocytic differentiation of normal hematopoietic cultures, anagrelide (0.3µm) reduced the rise in the mRNA levels of the transcription factors GATA-1 and FOG-1 as well as those of the downstream genes encoding FLI-1, NF-E2, glycoprotein IIb and MPL. However, the drug showed no effect on GATA-2 or RUNX-1 mRNA expression. Furthermore, anagrelide did not diminish the rise in GATA-1 and FOG-1 expression during erythropoietin-stimulated erythroid differentiation. Cilostamide, an exclusive and equipotent phosphodiesterase III (PDEIII) inhibitor, did not alter the expression of these genes. CONCLUSIONS: Anagrelide suppresses megakaryocytopoiesis by reducing the expression levels of GATA-1 and FOG-1 via a PDEIII-independent mechanism that is differentiation context-specific and does not involve inhibition of MPL-mediated early signal transduction events.


Assuntos
Fator de Transcrição GATA1/biossíntese , Regulação da Expressão Gênica , Proteínas Nucleares/biossíntese , Quinazolinas/farmacologia , Receptores de Trombopoetina/metabolismo , Fatores de Transcrição/biossíntese , Antígenos CD34/biossíntese , Plaquetas/efeitos dos fármacos , Linhagem Celular , Humanos , Megacariócitos/efeitos dos fármacos , Fosforilação , Agregação Plaquetária/efeitos dos fármacos , Inibidores da Agregação Plaquetária/farmacologia , Transdução de Sinais , Transcrição Gênica
11.
Biochem Biophys Res Commun ; 370(1): 174-8, 2008 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-18355441

RESUMO

The major phospholipid in pulmonary surfactant dipalmitoyl phosphatidylcholine (DPPC) has been shown to modulate inflammatory responses. Using human monocytes, this study demonstrates that DPPC significantly increased PGE(2) (P<0.05) production by 2.5-fold when compared to untreated monocyte controls. Mechanistically, this effect was concomitant with an increase in COX-2 expression which was abrogated in the presence of a COX-2 inhibitor. The regulation of COX-2 expression was independent of NF-kappaB activity. Further, DPPC increased the phosphorylation of the cyclic AMP response element binding protein (CREB; an important nuclear transcription factor important in regulating COX-2 expression). In addition, we also show that changing the fatty acid groups of PC (e.g. using l-alpha-phosphatidylcholine beta-arachidonoyl-gamma-palmitoyl (PAPC)) has a profound effect on the regulation of COX-2 expression and CREB activation. This study provides new evidence for the anti-inflammatory activity of DPPC and that this activity is at least in part mediated via CREB activation of COX-2.


Assuntos
1,2-Dipalmitoilfosfatidilcolina/metabolismo , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/antagonistas & inibidores , Ciclo-Oxigenase 2/metabolismo , Monócitos/enzimologia , Surfactantes Pulmonares/metabolismo , 1,2-Dipalmitoilfosfatidilcolina/química , 1,2-Dipalmitoilfosfatidilcolina/farmacologia , Células Cultivadas , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/metabolismo , Ciclo-Oxigenase 2/genética , Dinoprostona/biossíntese , Dinoprostona/metabolismo , Humanos , Monócitos/efeitos dos fármacos , Fosforilação , Surfactantes Pulmonares/química , Surfactantes Pulmonares/farmacologia
12.
Biochem Biophys Res Commun ; 366(1): 149-55, 2008 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-18053798

RESUMO

The PPARgamma agonist Rosiglitazone exerts anti-hyperglycaemic effects by regulating the long-term expression of genes involved in metabolism, differentiation and inflammation. In the present study, Rosiglitazone treatment rapidly inhibited (5-30 min) the ER Ca(2+) ATPase SERCA2b in monocytic cells (IC(50)=1.88 microM; p<0.05), thereby disrupting short-term Ca(2+) homeostasis (resting [Ca(2+)](cyto)=121.2+/-2.9% basal within 1h; p<0.05). However, extended Rosiglitazone treatment (72 h) induced dose-dependent SERCA2b up-regulation, and restored calcium homeostasis, in monocytic cells (SERCA2b mRNA: 138.7+/-5.7% basal (1 microM)/215.0+/-30.9% basal (10 microM); resting [Ca(2+)](cyto)=97.3+/-8.3% basal (10 microM)). As unfavourable cardiovascular outcomes, possibly related to disrupted cellular Ca(2+) homeostasis, have been linked to Rosiglitazone, this effect may be of clinical interest. In contrast, in PPRE-luciferase reporter-gene assays, Rosiglitazone induced non-dose-dependent PPARgamma-dependent effects (1 microM: 152.5+/-4.9% basal; 10 microM: 136.1+/-5.1% basal (p<0.05 for 1 microM vs. 10 microM)). Thus, we conclude that Rosiglitazone can exert PPARgamma-independent non-genomic effects, such as the SERCA2b inhibition seen here, but that long-term Rosiglitazone treatment did not perturb resting [Ca](cyto) in this study.


Assuntos
Cálcio/metabolismo , Homeostase/fisiologia , Monócitos/metabolismo , ATPases Transportadoras de Cálcio do Retículo Sarcoplasmático/metabolismo , Tiazolidinedionas/administração & dosagem , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Homeostase/efeitos dos fármacos , Humanos , Monócitos/efeitos dos fármacos , Rosiglitazona , ATPases Transportadoras de Cálcio do Retículo Sarcoplasmático/efeitos dos fármacos
13.
Yale J Biol Med ; 79(3-4): 173-5, 2006 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-17940628

RESUMO

BACKGROUND: Celiac disease (CD) and immunosuppression are the two risk factors for gastrointestinal, as well as non-gastrointestinal, non-Hodgkin's lymphomas (NHL). Recent large retrospective studies confirm that celiac disease significantly increases risk of developing small bowel lymphomas by 30 to 40 percent and other gut malignancies by 83-fold. CASE REPORT: A 75-year-old man with a history of CD of two-year duration presented with pallor, fatigue, and 20-pound weight loss of three weeks duration. There was a vague non-tender mass in the right hypochondrium, and his stools tested positive for occult blood. The lab values were within normal range, except for hemoglobin of 11mg/dL, MCV 75, mildly elevated SGOT of 61 IU/L, and LDH of about 5000 IU/L. Work-up including computerized tomography (CT) scan, positron emission tomography (PET) scan, and colonoscopy were performed. RESULTS: A CT scan of the abdomen showed extensive carcinomatosis, scattered lymphadenopathy, and small pleural effusions. PET scan results coincided with CT findings. Colonoscopy revealed a friable nodular mass in the hepatic flexure, histopathology of which confirmed a high-grade B-cell lymphoma. Flow cytometry following immunostaining was positive for CD10, CD19, CD20, CD45, CD79a, and Ki-67. FISH assay demonstrated t (14:18) translocation and bcl-2 rearrangement. The bone marrow biopsy showed evidence of disease. The patient was treated with rituximab, plus cyclophosphamide, Adriamycin, vincristine, and prednisone (CHOP-R), with intrathecal methotrexate prophylaxis. Currently, the patient remains in remission. CONCLUSION: This is the first case of aggressive Burkitt-like lymphoma (BLL) occurring in a patient with celiac disease in his eighth decade of life. It is possible that chronic inflammation, profound immunosuppression, and nutritional deficit could lead to development of high-grade B-cell lymphoproliferative disorders. Further molecular studies are warranted to the investigate the link between certain polymorphisms of human leukocyte antigens (HLA) in B-cell populations in the gut, and this might be useful to identify high-risk individuals in the population of patients with CD.


Assuntos
Linfoma de Burkitt/patologia , Doença Celíaca/complicações , Doença Celíaca/diagnóstico , Neoplasias do Colo/patologia , Neoplasias do Colo/secundário , Idoso , Células da Medula Óssea/patologia , Linfoma de Burkitt/diagnóstico , Neoplasias do Colo/diagnóstico , Colonoscopia/métodos , Genótipo , Antígenos HLA/química , Humanos , Imunossupressores/química , Hibridização in Situ Fluorescente , Inflamação , Masculino , Tomografia por Emissão de Pósitrons/métodos , Prognóstico , Tomografia Computadorizada por Raios X
14.
J Dent Res ; 83(2): 175-9, 2004 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-14742659

RESUMO

The reason that children with cleft palates tend to have a greater prevalence of tooth decay than normal children is unclear. We hypothesized that children with cleft palates would have increased oral clearance times for foods and, consequently, higher levels of caries and caries-associated micro-organisms than control children. Children aged 6-16 yrs, with (n = 81) or without (n = 61) cleft palates, were studied. Children with cleft palates had DMFT and dmft scores greater (p < 0.01) than those of the control group. The number of caries-associated organisms was greater in the saliva of the cleft palate children (all p < 0.001). The oral hygiene, plaque and gingival index scores were greater (p < 0.0001), oral clearance was longer (p < 0.01), and levels of sucrose and starch-derived saccharides higher (p < 0.01) in the cleft palate group. However, salivary concentrations of organic acids were lower in the children with craniofacial disorders, probably reflecting the altered physiology of the more mature dental biofilm. The longer oral clearance times of foods and the consequent generation of fermentable sugars from starches may contribute to the higher caries prevalence observed in children with cleft palates.


Assuntos
Fenda Labial/complicações , Fissura Palatina/complicações , Cárie Dentária/etiologia , Boca/metabolismo , Higiene Bucal , Adolescente , Biofilmes , Ácidos Carboxílicos/metabolismo , Distribuição de Qui-Quadrado , Criança , Fenda Labial/metabolismo , Fenda Labial/microbiologia , Fissura Palatina/metabolismo , Fissura Palatina/microbiologia , Contagem de Colônia Microbiana , Índice CPO , Cárie Dentária/microbiologia , Índice de Placa Dentária , Carboidratos da Dieta/metabolismo , Feminino , Humanos , Masculino , Boca/microbiologia , Índice de Higiene Oral , Índice Periodontal , Saliva/metabolismo , Saliva/microbiologia , Amido/metabolismo
15.
Diabetes Obes Metab ; 4(6): 376-8, 2002 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-12406034

RESUMO

Peroxisome proliferator activated receptor-gamma is an important factor in adipocyte differentiation and energy metabolism and is thus a candidate gene for obesity, insulin resistance and dyslipidaemia. We therefore assessed the associations between the most common variant of the PPAR-gamma, the Pro12Ala (P12A) substitution in the PPAR-gamma 2 gene, with BMI, blood pressure, fasting plasma glucose, HbA1c, total cholesterol, LDL and HDL cholesterol and plasma triglyceride in 183 treatment-naïve patients with type 2 diabetes (T2D). The P12A allele associated with lower fasting plasma glucose but had no influence on HbA1c or BMI. In obese patients (BMI > 29 kg/m2), the P12A substitution associated with elevated total and non-HDL cholesterol levels.


Assuntos
Diabetes Mellitus Tipo 2/genética , Diabetes Mellitus/genética , Mutação/genética , Obesidade , Receptores Citoplasmáticos e Nucleares/genética , Fatores de Transcrição/genética , Adulto , Idoso , Glicemia , Índice de Massa Corporal , Colesterol/sangue , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
17.
Science ; 292(5523): 1915-8, 2001 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-11397946

RESUMO

Experimental murine genetic models of complex human disease show great potential for understanding human disease pathogenesis. To reduce the time required for analysis of such models from many months down to milliseconds, a computational method for predicting chromosomal regions regulating phenotypic traits and a murine database of single nucleotide polymorphisms were developed. After entry of phenotypic information obtained from inbred mouse strains, the phenotypic and genotypic information is analyzed in silico to predict the chromosomal regions regulating the phenotypic trait.


Assuntos
Algoritmos , Mapeamento Cromossômico/métodos , Modelos Animais de Doenças , Polimorfismo de Nucleotídeo Único , Característica Quantitativa Herdável , Animais , Densidade Óssea , Cruzamentos Genéticos , Bases de Dados Factuais , Feminino , Ligação Genética , Genótipo , Humanos , Desequilíbrio de Ligação , Complexo Principal de Histocompatibilidade/genética , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos , Fenótipo , Reação em Cadeia da Polimerase , Software
18.
J Med Microbiol ; 50(1): 83-89, 2001 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-11192510

RESUMO

An earlier study reported that human cerebrospinal fluid (CSF) has fungistatic activity for Cryptococcus neoformans. The present study reports that molecular sieve fractionation of concentrated CSF yielded three protein peaks, one of which (p2) had anticryptococcal activity. On a DEAE-Sephacel anion-exchange column the active molecular sieve peak (p2) gave two peaks that contained anticryptococcal activity. The first (DEAE-1) eluted with 0.1 M NaCl and the second (DEAE-2) eluted with 0.2 M NaCl in buffer. Fungistatic activity of DEAE-1 was reversed by FeCl3. Moreover, FeCl3 reversed inhibition of C. neoformans growth by CSF. In contrast, activity of DEAE-2 was not reversed by FeCl3, indicating that inhibition was produced by an iron-independent mechanism. Immunoblot assays showed that transferrin was present in DEAE-1 but not in DEAE-2, whereas albumin was present in DEAE-2 but not in DEAE-1. On NuPAGE, DEAE-1 protein migrated as a single band corresponding to transferrin and DEAE-2 protein gave a single band corresponding to albumin. In control experiments, human serum albumin subjected to the same isolation protocol acquired anticryptococcal activity similar to that of DEAE-2. Therefore, CSF albumin (DEAE-2) activity was associated with the isolation protocol. These data indicate that transferrin, present in or isolated from CSF, sequesters trace amounts of ferric iron, inhibits growth of C. neoformans and acts as an innate defence mechanism.


Assuntos
Proteínas do Líquido Cefalorraquidiano/isolamento & purificação , Proteínas do Líquido Cefalorraquidiano/farmacologia , Cryptococcus neoformans/efeitos dos fármacos , Transferrina/líquido cefalorraquidiano , Transferrina/farmacologia , Líquido Cefalorraquidiano/química , Proteínas do Líquido Cefalorraquidiano/química , Cromatografia em Gel , Cromatografia por Troca Iônica/métodos , Cryptococcus neoformans/crescimento & desenvolvimento , Eletroforese em Gel de Poliacrilamida/métodos , Compostos Férricos/farmacologia , Humanos , Immunoblotting/métodos , Focalização Isoelétrica/métodos , Albumina Sérica/líquido cefalorraquidiano , Albumina Sérica/química , Albumina Sérica/farmacologia , Transferrina/química , Transferrina/isolamento & purificação
19.
Infect Immun ; 68(6): 3787-91, 2000 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-10816550

RESUMO

Human serum at low concentrations inhibits the growth of Cryptococcus neoformans in vitro. Fractionation of serum yielded a purified inhibitory protein with a molecular mass of approximately 81.8 kDa, a pI of approximately 6.2, and an amino acid sequence that matched that of human transferrin. The inhibitory activity and that of apotransferrin and 5% human serum were reversed by 10 microM freshly prepared FeCl(3).


Assuntos
Antifúngicos/farmacologia , Apoproteínas/farmacologia , Proteínas Sanguíneas/farmacologia , Cryptococcus neoformans/efeitos dos fármacos , Transferrina/farmacologia , Antifúngicos/isolamento & purificação , Apoproteínas/isolamento & purificação , Proteínas Sanguíneas/isolamento & purificação , Cloretos , Compostos Férricos/farmacologia , Humanos , Imunidade Inata , Transferrina/isolamento & purificação
20.
Anticancer Res ; 19(1B): 731-40, 1999.
Artigo em Inglês | MEDLINE | ID: mdl-10216485

RESUMO

BACKGROUND: Mitogenic signaling through the principal growth factor receptor tyrosine kinase (RTK) pathway, i.e. RTK-->Ras-->Raf-->Mek-->MAPK has been implicated in the pathogenesis of human cancer. However, biochemical characterization of this has not been adequately assessed in human cancers. MATERIALS AND METHODS: Using extracts from 23 human breast cancers and control tissue from the same resected specimens, the protein levels, phosphotransferase activities and subcellular locations of the mitogen-activated protein (MAP) kinase isoforms p42 Erk2 and p44 Erk1 were examined, together with their phosphotransferase activities towards myelin basic protein (MBP) and a peptide substrate patterned after the Thr-669 site in the epidermal growth factor receptor (EGFR T669) that is phosphorylated by MAP kinase. RESULTS: Overexpression of both Erk2 and Erk1 isoforms was evident using specific antibodies. A universal activation of MBP and EGFR T669 peptide phosphotransferase activities was also found (up to 3-fold). MonoQ fractionation resolved the bulk of the EGFR T669 peptide phosphorylation from elution of the MAP kinase protein. Erk1 and Erk2 activities determined by specific immunoprecipitation were increased by up to only 2.5-fold in only 50% of tumors overall. Immunohistochemical studies, using a monoclonal antibody specific for Erk2 demonstrated that the cellular distribution of this MAP kinase was similar in both control and tumor tissues, and Erk2 was largely confined to normal and malignant acini, whilst the intensity of staining was actually reduced in the tumor tissue. Mek1 and especially Mek2 protein expression, as well as MAP kinase kinase activity as determined by phosphorylation of kinase-inactive Erk [GST-K71A] were increased in cancer samples. CONCLUSIONS: a) This confirms that MAP kinase activity is increased in human breast cancer. However, the frequency and magnitude of this change is dependent upon the chosen methodology (i.e. crude lysate assays versus specific immunoprecipitation). b) A MAP-kinase-independent source of increased EGFR T669 phosphotransferase activity in tumor extracts has been demonstrated for the first time in human breast cancer. c) By immunohistochemistry, Erk2 protein was actually found to exhibit lower intensity in tumor samples; the increased expression was most likely due to its increased distribution. d) Increased Mek protein expression and activation have been demonstrated for the first time in human breast tumors.


Assuntos
Neoplasias da Mama/enzimologia , Proteínas Quinases Dependentes de Cálcio-Calmodulina/biossíntese , Proteína Quinase 1 Ativada por Mitógeno/biossíntese , Quinases de Proteína Quinase Ativadas por Mitógeno , Proteínas Quinases Ativadas por Mitógeno , Resinas de Troca Aniônica , Antígenos Nucleares , Western Blotting , Neoplasias da Mama/metabolismo , Cromatografia Líquida de Alta Pressão , Receptores ErbB/metabolismo , Feminino , Humanos , Imuno-Histoquímica , MAP Quinase Quinase 1 , MAP Quinase Quinase 2 , Proteína Quinase 3 Ativada por Mitógeno , Proteína Básica da Mielina/metabolismo , Proteínas Nucleares/metabolismo , Fosforilação , Proteínas Serina-Treonina Quinases/biossíntese , Proteínas Tirosina Quinases/biossíntese , Resinas Sintéticas , Transdução de Sinais/fisiologia
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