35 research outputs found
Modeling nitrous acid and its impact on ozone and hydroxyl radical during the Texas Air Quality Study 2006
Nitrous acid (HONO) mixing ratios for the Houston metropolitan area were simulated with the Community Multiscale Air Quality (CMAQ) Model for an episode during the Texas Air Quality Study (TexAQS) II in August/September 2006 and compared to in-situ MC/IC (mist-chamber/ion chromatograph) and long path DOAS (Differential Optical Absorption Spectroscopy) measurements at three different altitude ranges. Several HONO sources were accounted for in simulations, such as gas phase formation, direct emissions, nitrogen dioxide (NO<sub>2</sub>) hydrolysis, photo-induced formation from excited NO<sub>2</sub> and photo-induced conversion of NO<sub>2</sub> into HONO on surfaces covered with organic materials. Compared to the gas-phase HONO formation there was about a tenfold increase in HONO mixing ratios when additional HONO sources were taken into account, which improved the correlation between modeled and measured values. Concentrations of HONO simulated with only gas phase chemistry did not change with altitude, while measured HONO concentrations decrease with height. A trend of decreasing HONO concentration with altitude was well captured with CMAQ predicted concentrations when heterogeneous chemistry and photolytic sources of HONO were taken into account. Heterogeneous HONO production mainly accelerated morning ozone formation, albeit slightly. Also HONO formation from excited NO<sub>2</sub> only slightly affected HONO and ozone (O<sub>3</sub>) concentrations. Photo-induced conversion of NO<sub>2</sub> into HONO on surfaces covered with organic materials turned out to be a strong source of daytime HONO. Since HONO immediately photo-dissociates during daytime its ambient mixing ratios were only marginally altered (up to 0.5 ppbv), but significant increase in the hydroxyl radical (OH) and ozone concentration was obtained. In contrast to heterogeneous HONO formation that mainly accelerated morning ozone formation, inclusion of photo-induced surface chemistry influenced ozone throughout the day
Angiogenesis extent and macrophage density increase simultaneously with pathological progression in B-cell non-Hodgkin's lymphomas
Node biopsies of 30 benign lymphadenopathies and 71 B-cell non-Hodgkin's lymphomas (B-NHLs) were investigated for microvessel and macrophage counts using immunohistochemistry and morphometric analysis. Both counts were significantly higher in B-NHL. Moreover, when these were grouped into low-grade and high-grade lymphomas, according to the Kiel classification and Working Formulation (WF), statistically significant higher counts were found in the high-grade tumours. Immunohistochemistry and electron microscopy revealed a close spatial association between microvessels and macrophages. Overall, the results suggest that, in analogy to what has already been shown in solid tumours, angiogenesis occurring in B-NHLs increases with tumour progression, and that macrophages promote the induction of angiogenesis via the release of their angiogenic factors. © 1999 Cancer Research Campaig
The genetic landscape of immune-competent and HIV lymphoma
This journal supplement is Proceedings of the 13th International Conference on Malignancies in AIDS and Other Acquired Immunodeficiencies (ICMAOI)Open Access JournalBurkitt lymphoma (BL) and diffuse large B cell lymphoma (DLBCL) are aggressive forms of lymphoma in adults and demonstrate overlapping morphology, immunophenotype and clinical behavior. The risk of developing these tumors increases ten to hundred-fold in the setting of HIV infection. The genetic causes and the role of specific mutations, especially in the setting of HIV, are largely unknown.
The decoding of the human genome and the advent of high-throughput sequencing have provided rich opportunities for the comprehensive identification of the genetic causes of cancer. In order to comprehensively identify genes that are recurrently mutated in immune-competent DLBCL and BL, we obtained a total of 92 cases of DLBCLs and 40 cases of BL. These cases were compared to a set of 5 DLBCLs and BL tumors derived from patients with HIV. The DLBCL cases were divided into a discovery set (N=34) and âŠlink_to_OA_fulltextThe 13th International Conference on Malignancies in AIDS and Other Acquired Immunodeficiencies (ICAMAOI), Bethesda, MD., 7-8 November 2011. In Infectious Agents and Cancer, 2011, v. 7 suppl. 1, article no. O
The genetic landscape of mutations in Burkitt lymphoma
Burkitt lymphoma is characterized by deregulation of MYC, but the contribution of other genetic mutations to the disease is largely unknown. Here, we describe the first completely sequenced genome from a Burkitt lymphoma tumor and germline DNA from the same affected individual. We further sequenced the exomes of 59 Burkitt lymphoma tumors and compared them to sequenced exomes from 94 diffuse large B-cell lymphoma (DLBCL) tumors. We identified 70 genes that were recurrently mutated in Burkitt lymphomas, including ID3, GNA13, RET, PIK3R1 and the SWI/SNF genes ARID1A and SMARCA4. Our data implicate a number of genes in cancer for the first time, including CCT6B, SALL3, FTCD and PC. ID3 mutations occurred in 34% of Burkitt lymphomas and not in DLBCLs. We show experimentally that ID3 mutations promote cell cycle progression and proliferation. Our work thus elucidates commonly occurring gene-coding mutations in Burkitt lymphoma and implicates ID3 as a new tumor suppressor gene
Comprehensive gene expression profiling and immunohistochemical studies support application of immunophenotypic algorithm for molecular subtype classification in diffuse large B-cell lymphoma: a report from the International DLBCL Rituximab-CHOP Consortium Program Study
Gene expression profiling (GEP) has stratified diffuse large B-cell lymphoma (DLBCL) into molecular subgroups that correspond to different stages of lymphocyte development - namely germinal center B-cell-like and activated B-cell-like. This classification has prognostic significance, but GEP is expensive and not readily applicable into daily practice, which has lead to immunohistochemical algorithms proposed as a surrogate for GEP analysis. We assembled tissue microarrays from 475 de novo DLBCL patients who were treated with rituximab-CHOP chemotherapy. All cases were successfully profiled by GEP on formalin-fixed, paraffin-embedded tissue samples. Sections were stained with antibodies reactive with CD10, GCET1, FOXP1, MUM1, and BCL6 and cases were classified following a rationale of sequential steps of differentiation of B-cells. Cutoffs for each marker were obtained using receiver operating characteristic curves, obviating the need for any arbitrary method. An algorithm based on the expression of CD10, FOXP1, and BCL6 was developed that had a simpler structure than other recently proposed algorithms and 92.6% concordance with GEP. In multivariate analysis, both the International Prognostic Index and our proposed algorithm were significant independent predictors of progression-free and overall survival. In conclusion, this algorithm effectively predicts prognosis of DLBCL patients matching GEP subgroups in the era of rituximab therapy
The 5th edition of the World Health Organization classification of haematolymphoid tumours: lymphoid neoplasms
We herein present an overview of the upcoming 5th edition of the World Health Organization Classification of Haematolymphoid Tumours focussing on lymphoid neoplasms. Myeloid and histiocytic neoplasms will be presented in a separate accompanying article. Besides listing the entities of the classification, we highlight and explain changes from the revised 4th edition. These include reorganization of entities by a hierarchical system as is adopted throughout the 5th edition of the WHO classification of tumours of all organ systems, modification of nomenclature for some entities, revision of diagnostic criteria or subtypes, deletion of certain entities, and introduction of new entities, as well as inclusion of tumour-like lesions, mesenchymal lesions specific to lymph node and spleen, and germline predisposition syndromes associated with the lymphoid neoplasms
Correction: âThe 5th edition of The World Health Organization Classification of Haematolymphoid Tumours: Lymphoid Neoplasmsâ Leukemia. 2022 Jul;36(7):1720â1748
Impact of updated traffic emissions on HONO mixing ratios simulated for urban site in Houston, Texas
Recent measurements in Houston show that HONO traffic emissions are 1.7%
of NO<sub>x</sub> emissions, which is about twice the previously estimated value of
0.8% based on tunnel measurements in 2001. The 0.8% value is widely
used to estimate mobile emissions of HONO for air quality modeling
applications. This study applies the newly estimated HONO / NO<sub>x</sub> ratio in
the WRFâSMOKEâCMAQ modeling system and estimates the impact of higher HONO
traffic emissions on its mixing ratios. Since applied emission inventory
resulted in overestimates of NO<sub>x</sub> mixing ratios and because HONO
emissions and chemical formation depend on the magnitude of NO<sub>x</sub>, thus,
before proceeding with HONO emission modifications emissions of NO<sub>x</sub>
were adjusted to reflect current emission trends. The modeled mixing ratios
of NO<sub>x</sub> were evaluated against measured data from a number of sites in
the Houston area. Overall, the NO<sub>x</sub> mean value dropped from 11.11 ppbv
in the base case to 7.59 ppbv in the NO<sub>x</sub>-adjusted case becoming much
closer to the observed mean of 7.76 ppbv. The index of agreement (IOA) is
improved in the reduced NO<sub>x</sub> case (0.71 vs. 0.75) and the absolute mean
error (AME) is lowered from 6.76 to 4.94. The modeled mixing ratios of HONO
were evaluated against the actual observed values attained at the Moody
Tower in Houston. The model could not reproduce the morning HONO peaks when
the low HONO / NO<sub>x</sub> ratio of 0.008 was used to estimate HONO emissions.
Doubling HONO emissions from mobile sources resulted in higher mixing
ratios, and the mean value increased from 0.30 to 0.41 ppbv becoming closer
to the observed mean concentrations of 0.69 but still low; AME was slightly
reduced from 0.46 to 0.43. IOA for simulation that used the 2001 emission
values is 0.63 while for simulation with higher HONO emission it increased
to 0.70. Increased HONO emissions from mobile sources resulted in a 14%
increase in OH during morning time at the location of the Moody Tower and
3% when averaged over an urban area. The increase calculated for daytime was
7 and 1% for the Moody Tower and the urban area, respectively. The
impact on ozone was found to be marginal. This study results shed light on
the underestimated HONO and OH in the morning from global/regional chemical
transport models with the typical emission of 0.8% HONO emission out of
the total NO<sub>x</sub> emissions
Development and evaluation of the Screening Trajectory Ozone Prediction System (STOPS, version 1.0)
A hybrid LagrangianâEulerian based modeling tool has been developed using
the Eulerian framework of the Community Multiscale Air Quality (CMAQ) model.
It is a moving nest that utilizes saved original CMAQ simulation results to
provide boundary conditions, initial conditions, as well as emissions and
meteorological parameters necessary for a simulation. Given that these files
are available, this tool can run independently of the CMAQ whole domain
simulation, and it is designed to simulate sourceâreceptor relationships
upon changes in emissions. In this tool, the original CMAQ's horizontal
domain is reduced to a small sub-domain that follows a trajectory defined by
the mean mixed-layer wind. It has the same vertical structure and physical
and chemical interactions as CMAQ except advection calculation. The advantage
of this tool compared to other Lagrangian models is its capability of
utilizing realistic boundary conditions that change with space and time as
well as detailed chemistry treatment. The correctness of the algorithms and
the overall performance was evaluated against CMAQ simulation results. Its
performance depends on the atmospheric conditions occurring during the
simulation period, with the comparisons being most similar to CMAQ results
under uniform wind conditions. The mean bias for surface ozone mixing ratios
varies between â0.03 and â0.78 ppbV and the slope is between 0.99 and
1.01 for different analyzed cases. For complicated meteorological conditions,
such as wind circulation, the simulated mixing ratios deviate from CMAQ
values as a result of the Lagrangian approach of using mean wind for its
movement, but are still close, with the mean bias for ozone varying between
0.07 and â4.29 ppbV and the slope varying between 0.95 and 1.06 for
different analyzed cases. For historical reasons, this hybrid
LagrangianâEulerian based tool is named the Screening Trajectory Ozone
Prediction System (STOPS), but its use is not limited to ozone prediction as,
similarly to CMAQ, it can simulate concentrations of many species, including
particulate matter and some toxic compounds, such as formaldehyde and
1,3-butadiene