1
|
Kittelson DB, Swanson J, Aldridge M, Giannelli RA, Kinsey JS, Stevens JA, Liscinsky DS, Hagen D, Leggett C, Stephens K, Hoffman B, Howard R, Frazee RW, Silvis W, McArthur T, Lobo P, Achterberg S, Trueblood M, Thomson K, Wolff L, Cerully K, Onasch T, Miake-Lye R, Freedman A, Bachalo W, Payne G. Experimental verification of principal losses in a regulatory particulate matter emissions sampling system for aircraft turbine engines. AEROSOL SCIENCE AND TECHNOLOGY : THE JOURNAL OF THE AMERICAN ASSOCIATION FOR AEROSOL RESEARCH 2021; 56:63-74. [PMID: 35602286 PMCID: PMC9118390 DOI: 10.1080/02786826.2021.1971152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 07/07/2021] [Accepted: 07/30/2021] [Indexed: 06/15/2023]
Abstract
A sampling system for measuring emissions of nonvolatile particulate matter (nvPM) from aircraft gas turbine engines has been developed to replace the use of smoke number and is used for international regulatory purposes. This sampling system can be up to 35 m in length. The sampling system length in addition to the volatile particle remover (VPR) and other sampling system components lead to substantial particle losses, which are a function of the particle size distribution, ranging from 50 to 90% for particle number concentrations and 10-50% for particle mass concentrations. The particle size distribution is dependent on engine technology, operating point, and fuel composition. Any nvPM emissions measurement bias caused by the sampling system will lead to unrepresentative emissions measurements which limit the method as a universal metric. Hence, a method to estimate size dependent sampling system losses using the system parameters and the measured mass and number concentrations was also developed (SAE 2017; SAE 2019). An assessment of the particle losses in two principal components used in ARP6481 (SAE 2019) was conducted during the VAriable Response In Aircraft nvPM Testing (VARIAnT) 2 campaign. Measurements were made on the 25-meter sample line portion of the system using multiple, well characterized particle sizing instruments to obtain the penetration efficiencies. An agreement of ± 15% was obtained between the measured and the ARP6481 method penetrations for the 25-meter sample line portion of the system. Measurements of VPR penetration efficiency were also made to verify its performance for aviation nvPM number. The research also demonstrated the difficulty of making system loss measurements and substantiates the E-31 decision to predict rather than measure system losses.
Collapse
|
2
|
Hoffman B, Kuhl M, Knight V, Phillips M, Rabinovitch N. CANNABIS ALLERGY IN A YOUNG CHILD WITH SEVERE ASTHMA EXPOSED TO SECONDHAND MARIJUANA SMOKE. Ann Allergy Asthma Immunol 2018. [DOI: 10.1016/j.anai.2018.09.268] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
3
|
Levis C, Costa FRC, Bongers F, Peña-Claros M, Clement CR, Junqueira AB, Neves EG, Tamanaha EK, Figueiredo FOG, Salomão RP, Castilho CV, Magnusson WE, Phillips OL, Guevara JE, Sabatier D, Molino JF, López DC, Mendoza AM, Pitman NCA, Duque A, Vargas PN, Zartman CE, Vasquez R, Andrade A, Camargo JL, Feldpausch TR, Laurance SGW, Laurance WF, Killeen TJ, Nascimento HEM, Montero JC, Mostacedo B, Amaral IL, Guimarães Vieira IC, Brienen R, Castellanos H, Terborgh J, Carim MDJV, Guimarães JRDS, Coelho LDS, Matos FDDA, Wittmann F, Mogollón HF, Damasco G, Dávila N, García-Villacorta R, Coronado ENH, Emilio T, Filho DDAL, Schietti J, Souza P, Targhetta N, Comiskey JA, Marimon BS, Marimon BH, Neill D, Alonso A, Arroyo L, Carvalho FA, de Souza FC, Dallmeier F, Pansonato MP, Duivenvoorden JF, Fine PVA, Stevenson PR, Araujo-Murakami A, Aymard C. GA, Baraloto C, do Amaral DD, Engel J, Henkel TW, Maas P, Petronelli P, Revilla JDC, Stropp J, Daly D, Gribel R, Paredes MR, Silveira M, Thomas-Caesar R, Baker TR, da Silva NF, Ferreira LV, Peres CA, Silman MR, Cerón C, Valverde FC, Di Fiore A, Jimenez EM, Mora MCP, Toledo M, Barbosa EM, Bonates LCDM, Arboleda NC, Farias EDS, Fuentes A, Guillaumet JL, Jørgensen PM, Malhi Y, de Andrade Miranda IP, Phillips JF, Prieto A, Rudas A, Ruschel AR, Silva N, von Hildebrand P, Vos VA, Zent EL, Zent S, Cintra BBL, Nascimento MT, Oliveira AA, Ramirez-Angulo H, Ramos JF, Rivas G, Schöngart J, Sierra R, Tirado M, van der Heijden G, Torre EV, Wang O, Young KR, Baider C, Cano A, Farfan-Rios W, Ferreira C, Hoffman B, Mendoza C, Mesones I, Torres-Lezama A, Medina MNU, van Andel TR, Villarroel D, Zagt R, Alexiades MN, Balslev H, Garcia-Cabrera K, Gonzales T, Hernandez L, Huamantupa-Chuquimaco I, Manzatto AG, Milliken W, Cuenca WP, Pansini S, Pauletto D, Arevalo FR, Reis NFC, Sampaio AF, Giraldo LEU, Sandoval EHV, Gamarra LV, Vela CIA, ter Steege H. Persistent effects of pre-Columbian plant domestication on Amazonian forest composition. Science 2017; 355:925-931. [DOI: 10.1126/science.aal0157] [Citation(s) in RCA: 306] [Impact Index Per Article: 43.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 01/20/2017] [Indexed: 11/02/2022]
|
4
|
Payabvash S, Benson J, Taleb S, Rykken J, Hoffman B, McKinney A, Oswood M. Susceptible vessel sign: identification of arterial occlusion and clinical implications in acute ischaemic stroke. Clin Radiol 2017; 72:116-122. [DOI: 10.1016/j.crad.2016.11.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Accepted: 11/01/2016] [Indexed: 10/20/2022]
|
5
|
Benson JC, Payabvash S, Hoffman B, Oswood M, McKinney AM. Reply. AJNR Am J Neuroradiol 2017; 38:E13. [PMID: 27737861 DOI: 10.3174/ajnr.a4991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
6
|
Nandwana V, Ryoo SR, Kanthala S, Kumar A, Sharma A, Castro FC, Li Y, Hoffman B, Lim S, Dravid VP. Engineered ferritin nanocages as natural contrast agents in magnetic resonance imaging. RSC Adv 2017. [DOI: 10.1039/c7ra05681h] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Here we report the development of a “natural” MRI contrast agent with tunable Fe loading and a magnetic core for magnetic resonance imaging.
Collapse
|
7
|
Benson JC, Payabvash S, Mortazavi S, Zhang L, Salazar P, Hoffman B, Oswood M, McKinney AM. CT Perfusion in Acute Lacunar Stroke: Detection Capabilities Based on Infarct Location. AJNR Am J Neuroradiol 2016; 37:2239-2244. [PMID: 27538902 DOI: 10.3174/ajnr.a4904] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Accepted: 06/27/2016] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Recent studies demonstrated superiority of CTP to NCCT/CTA at detecting lacunar infarcts. This study aimed to assess CTP's capability to identify lacunae in different intracranial regions. MATERIALS AND METHODS Over 5.5 years, 1085 CTP examinations were retrospectively reviewed in patients with acute stroke symptoms with CTP within 12 hours and MRI within 7 days of symptom onset. Patients had infarcts ≤2 cm or no acute infarct on DWI; patients with concomitant infarcts >2 cm on DWI were excluded. CTP postprocessing was automated by a delay-corrected algorithm. Three blinded reviewers were given patient NIHSS scores and symptoms; infarcts were recorded based on NCCT/CTA, CTP (CBF, CBV, MTT, and TTP), and DWI. RESULTS One hundred thirteen patients met inclusion criteria (53.1% female). On DWI, lacunar infarcts were present in 37 of 113 (32.7%), and absent in 76 of 113 (67.3%). On CTP, lacunar infarcts typically appeared as abnormalities larger than infarct size on DWI. Interobserver κ for CTP ranged from 0.38 (CBF) (P < .0001) to 0.66 (TTP) (P < .0001); interobserver κ for DWI was 0.88 (P < 0.0001). In all intracranial regions, sensitivity of CTP ranged from 18.9% (CBV) to 48.7% (TTP); specificity ranged from 97.4% (CBF and TTP) to 98.7% (CBV and MTT). CTP's sensitivity was highest in the subcortical white matter with or without cortical involvement (21.7%-65.2%) followed by periventricular white matter (12.5%-37.5%); sensitivity in the thalami or basal ganglia was 0%. CONCLUSIONS CTP has low sensitivity and high specificity in identifying lacunar infarcts. Sensitivity is highest in the subcortical white matter with or without cortical involvement, but limited in the basal ganglia and thalami.
Collapse
|
8
|
Bailitz J, Nolting L, Ferre R, Cosby K, Budhram G, Bengiamin R, Baty G, Hoffman B, Summers S, Hunt P. The Portal Research Network: Defining the Learning Curve of Emergency Medicine Resident Point-of-Care Trainees. Ann Emerg Med 2013. [DOI: 10.1016/j.annemergmed.2013.07.036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
|
9
|
Ahmed A, Hoffman B, Harland K, Skeete D, Choi K, Liao J. 257 Not Just an Urban Phenomenon: Uninsured Trauma Patients in Rural Setting at Risk for Increased Mortality. Ann Emerg Med 2012. [DOI: 10.1016/j.annemergmed.2012.06.235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
10
|
Bailey D, Rokhforooz F, Hoffman B. Analytical evaluation of two enzymatic methods for the measurement of total bile acid in intrahepatic cholestasis of pregnancy. Clin Biochem 2012. [DOI: 10.1016/j.clinbiochem.2012.07.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
11
|
Estey M, Shea J, Bozovic A, Rokhforooz F, Hoffman B, Vieth R. Evaluation of the Roche vitamin D total {25-hydroxyvitamin D2 and D3; (25(OH)D)} immunoassay. Clin Biochem 2012. [DOI: 10.1016/j.clinbiochem.2012.07.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
12
|
Abu Hassan Abu D, Franken DR, Hoffman B, Henkel R. Accurate sperm morphology assessment predicts sperm function. Andrologia 2011; 44 Suppl 1:571-7. [PMID: 22040054 DOI: 10.1111/j.1439-0272.2011.01229.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Sperm morphology has been associated with in vitro as well as in vivo fertilisation. The study aimed to evaluate the possible relation between the percentage of spermatozoa with normal morphology and the following sperm functional assays: (i) zona-induced acrosome reaction (ZIAR); (ii) DNA integrity; (iii) chromatin condensation; (iv) sperm apoptosis; and (v) fertilisation rates. Regression analysis was employed to calculate the association between morphology and different functional tests. Normal sperm morphology correlated significantly with the percentages of live acrosome-reacted spermatozoa in the ZIAR (r = 0.518; P < 0.0001; n = 92), DNA integrity (r = -0.515; P = 0.0018; n = 34), CMA(3) -positive spermatozoa (r = -0.745; P < 0.0001; n = 92), sperm apoptosis (r = -0.395; P = 0.0206; n = 34) and necrosis (r = -0.545; P = 0.0009; n = 34). Negative correlations existed between for the acrosome reaction, and DNA integrity, while negative associations were recorded with the percentages of CMA(3) -positive spermatozoa, apoptotic and necrotic spermatozoa. Sperm morphology is related to sperm dysfunction such as poor chromatin condensation, acrosome reaction and DNA integrity. Negative and significant correlations existed between normal sperm morphology and chromatin condensation, the percentage of spermatozoa with abnormal DNA and spermatozoa with apoptotic activity. The authors do not regard sperm morphology as the only test for the diagnosis of male fertility, but sperm morphology can serve as a valuable indicator of underlying dysfunction.
Collapse
|
13
|
Sullivan R, Buresh C, Young T, Peek-Asa C, Hoffman B, Torner J. 331 Increased Risk of Inpatient Mortality Among Uninsured Traumatic Injury Patients in a Rural State Trauma Registry. Ann Emerg Med 2011. [DOI: 10.1016/j.annemergmed.2011.06.362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
14
|
Radigan J, MacMillan C, Hoffman B, Freeman J. Intraoperative parathyroid hormone levels as a predictor of glandular weight. Clin Biochem 2011. [DOI: 10.1016/j.clinbiochem.2011.06.054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
15
|
Shaw J, Konforte D, Hoffman B, Azad A. Comparision of hemoglobin A1c (HbAIc) measurement in whole blood vs measurement in blood extracted from dried blood spots (DBS) using the tina-quant hemoglobin A1c GEN. 2 method on the cobas integra 400 plus analyzer. Clin Biochem 2011. [DOI: 10.1016/j.clinbiochem.2011.06.058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
|
16
|
Konforte D, Shaw J, Taha N, Bozovic A, Rokhforooz F, Hoffman B, Vieth R. Analytical evaluation of the IDS-iSYS 25-Hydroxy vitamin D (25(OH)D) immunoassay. Clin Biochem 2011. [DOI: 10.1016/j.clinbiochem.2011.06.039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|
17
|
Abu DAH, Franken DR, Hoffman B, Henkel R. Sequential analysis of sperm functional aspects involved in fertilisation: a pilot study. Andrologia 2011; 44 Suppl 1:175-81. [PMID: 21729136 DOI: 10.1111/j.1439-0272.2010.01156.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
The development of diagnostic techniques in andrology as a second level of approach to the diagnosis of male factor infertility has enthused the focus of researchers on the development of a sequential diagnostic programme for these men. Semen samples of 78 men form couples undergoing in vitro fertilisation therapy were used in the study. The semen samples were used to test sperm functional aspects known to interfere with fertilisation. These tests included semen profile, DNA integrity, apoptosis, chromatin packaging, acridin orange staining, zona binding capacity, zona-induced acrosome reaction (AR). Results were correlated with fertilisation outcome. Statistical analyses of the recorded data were carried out using a logistic regression analysis model on all sperm functional tests. A negative and significant association with the fertilisation rates was recorded for DNA damage (r = -0.56; P ≤ 0.0005). A positive significant correlation was recorded between fertilisation rates and sperm with normal DNA (r = -0.57, P ≤ 0.0004), and zona-induced AR (r = 0.33, P ≤ 0.002). Diagnostic andrology can be regarded as a mandatory part of the male factor patient's work-up schedule to assist clinicians with the most suitable therapeutic modality to follow.
Collapse
|
18
|
Hoffman B, Carroll T, Lichtwark G, Cresswell A. The effect of varying musculotendinous length on the construction of triceps surae length-tension curves. J Sci Med Sport 2010. [DOI: 10.1016/j.jsams.2010.10.512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
19
|
Dragano N, Pikhart H, Jöckel K, Verde P, Hoffman B, Moebus S, Erbel R, Tiller D, Riedel N, Bobak M, Siegrist J, Greiser K. Stadtgesundheit in Europa – Unterschiede im Rauchverhalten zwischen zehn Städten und mögliche Hintergründe. Eine vergleichende Mehrebenenanalyse aus Daten der CARLA-, HAPIEE-, und HNR- Studie. DAS GESUNDHEITSWESEN 2010. [DOI: 10.1055/s-0030-1266376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
|
20
|
Fortuna J, Bonomo J, Hoffman B, James L, Shutter L, Butler K. QS228. Radiographic Findings in Elderly Patients With Pre-Injury Anti-Platelet Use and Hemorrhagic Brain Injury. J Surg Res 2009. [DOI: 10.1016/j.jss.2008.11.530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
21
|
Gibbs JD, Liebermann DA, Hoffman B. Leukemia suppressor function of Egr-1 is dependent on transforming oncogene. Leukemia 2008; 22:1909-16. [DOI: 10.1038/leu.2008.189] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
|
22
|
Chaudhary UB, Gudena V, Milling DL, O'Brien P, Montero AJ, Brashears J, Marshall D, Hoffman B, Garrett-Mayer E, Esnaola N. Preliminary results of a phase II neoadjuvant trial with gemcitabine/oxaliplatin and cetuximab followed by surgery or concurrent intensity modulated radiation therapy (IMRT) with capecitabine for patients with borderline resectable and unresectable nonmetastatic pancreatic cancer. J Clin Oncol 2008. [DOI: 10.1200/jco.2008.26.15_suppl.15506] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
|
23
|
Jani N, Dewitt J, Eloubeidi M, Varadarajulu S, Appalaneni V, Hoffman B, Brugge W, Lee K, Khalid A, McGrath K. Endoscopic ultrasound-guided fine-needle aspiration for diagnosis of solid pseudopapillary tumors of the pancreas: a multicenter experience. Endoscopy 2008; 40:200-3. [PMID: 18067066 DOI: 10.1055/s-2007-995364] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND AND STUDY AIMS Solid pseudopapillary tumors of the pancreas are rare, low-grade, epithelial neoplasms that are usually discovered incidentally in young women. Distinguishing solid pseudopapillary tumors from other pancreatic tumors, especially pancreatic endocrine tumors, can be challenging. The role of endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) in this context remains unclear. The purpose of this study was to describe the endoscopic ultrasound features of solid pseudopapillary tumors and the role of EUS-FNA in the preoperative diagnosis of these tumors. PATIENTS AND METHODS Patients from five tertiary referral centers with surgically confirmed solid pseudopapillary tumors who had undergone preoperative EUS-FNA were included. The endoscopic ultrasound findings, cytologic descriptions, immunostaining results, operative records, surgical pathology, and results of the most recent clinical follow-up were reviewed. RESULTS A total of 28 patients were identified (four men [14 %], 24 women [86 %], mean age +/- standard deviation [SD] 35 +/- 10 years). Solid pseudopapillary tumors had been found as incidental findings on cross-sectional imaging in 50 % of cases. The mean tumor size +/- SD was 42 +/- 19.5 mm and the majority were located in the pancreatic body and tail. The endoscopic ultrasound report described a well-defined, echo-poor mass in 86 %; the tumors were solid in 14 patients (50 %), mixed solid and cystic in 11 patients (39 %), and cystic in three patients (11 %). A preoperative diagnosis of solid pseudopapillary tumor was made in 21 patients (75 %) on the basis of EUS-FNA cytology. Surgical resection was performed in all cases. Laparoscopic resection was performed in eight of these patients (29 %). CONCLUSIONS A solid pseudopapillary tumor should be included in the differential diagnosis of any well-demarcated, echo-poor, solid or mixed solid/cystic pancreatic lesion seen during endoscopic ultrasound, particularly in young women. The diagnostic accuracy of EUS-FNA for solid pseudopapillary tumors was 75 % in this study. A definitive preoperative diagnosis can guide the surgical approach in selected cases.
Collapse
|
24
|
Gibbs JD, Liebermann DA, Hoffman B. Egr-1 abrogates the E2F-1 block in terminal myeloid differentiation and suppresses leukemia. Oncogene 2007; 27:98-106. [PMID: 17599039 DOI: 10.1038/sj.onc.1210627] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Deregulated growth and blocks in differentiation collaborate in the multistage process of leukemogenesis. Previously, we have shown that ectopic expression of the zinc finger transcription factor Egr-1 in M1 myeloblastic leukemia cells promotes terminal differentiation with interleukin-6 (IL-6). In addition, we have shown that deregulated expression of the oncogene E2F-1 blocks the myeloid terminal differentiation program, resulting in proliferation of immature cells in the presence of IL-6. Here it is shown that the positive regulator of differentiation Egr-1 abrogates the E2F-1-driven block in myeloid terminal differentiation. The M1E2F-1/Egr-1 cells underwent G(0)/G(1) arrest and functional macrophage maturation following treatment with IL-6. Furthermore, Egr-1 diminished the aggressiveness of M1E2F-1 leukemias and abrogated the leukemic potential of IL-6-treated M1E2F-1 cells. Previously, we reported that Egr-1 abrogated the block in terminal myeloid differentiation imparted by deregulated c-myc, which blocks differentiation at a later stage than E2F-1, resulting in cells that have the characteristics of functionally mature macrophages that did not undergo G(0)/G(1) arrest. Taken together, this work extends and highlights the tumor suppressor role of Egr-1, with Egr-1 behaving as a tumor suppressor against two oncogenes, each blocking myeloid differentiation by a different mechanism. These findings suggest that Egr-1 and/or Egr-1 target genes may be useful tools to treat or suppress oncogene-driven hematological malignancies.
Collapse
|
25
|
Vesely DL, Hoffman B, Liebermann DA. Phosphatidylinositol 3-kinase/Akt signaling mediates interleukin-6 protection against p53-induced apoptosis in M1 myeloid leukemic cells. Oncogene 2006; 26:3041-50. [PMID: 17099722 DOI: 10.1038/sj.onc.1210109] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
M1 myeloid leukemic cells were used to dissect the molecular mechanisms of myeloid cell survival and apoptosis. A salient feature of M1 cells is that they respond to the physiological survival factor interleukin-6 (IL-6), yet lack the tumor suppressor gene p53. Functional wild-type activation of temperature-sensitive p53 protein (p53 val) at permissive temperature in M1-t-p53 cells results in rapid apoptosis, which is blocked by IL-6. How p53 induces M1 apoptosis and how IL-6 protects against p53-induced apoptosis are not fully understood. Here it is shown that p53-mediated apoptosis of M1 cells involves rapid activation of the proapoptotic Fas/CD95 death pathway, which activates caspases 8 and 10. Functional p53 also targets the mitochondria, causing upregulation of proapoptotic Bax, downregulation of prosurvival Bcl-2 and activation of caspase 9. IL-6 was found to protect against p53-induced apoptosis via activation of the PI3K/Akt survival pathway, which in turn counters both the Fas/CD95 and mitochondrial apoptotic pathways and activates the prosurvival transcription factor nuclear factor-kappaB (NF-kappaB). Taken together, this work supports a novel model for leukemic progression where cells that acquire the ability to produce an autocrine survival factor, such as IL-6, can bypass normal p53 surveillance function by targeting Akt, which in turn can exert effects on the regulators of apoptosis, such as the Fas/CD95 pathway, the mitochondria and NF-kappaB.
Collapse
|