Isoprene emissions in Africa inferred from OMI observations of formaldehyde columns.

We use 2005-2009 satellite observations of formaldehyde (HCHO) columns from the OMI instrument to infer biogenic isoprene emissions at monthly 1 × 1° resolution over the African continent. Our work includes new approaches to remove biomass burning influences using OMI absorbing aerosol optical depth data (to account for transport of fire plumes) and anthropogenic influences using AATSR satellite data for persistent small-flame fires (gas flaring). The resulting biogenic HCHO columns (ΩHCHO) from OMI follow closely the distribution of vegetation patterns in Africa. We infer isoprene emission (E ISOP) from the local sensitivity S = ΔΩHCHO / ΔE ISOP derived with the GEOS-Chem chemical transport model using two alternate isoprene oxidation mechanisms, and verify the validity of this approach using AMMA aircraft observations over West Africa and a longitudinal transect across central Africa. Displacement error (smearing) is diagnosed by anomalously high values of S and the corresponding data are removed. We find significant sensitivity of S to NOx under low-NOx conditions that we fit to a linear function of tropospheric column NO2. We estimate a 40% error in our inferred isoprene emissions under high-NOx conditions and 40-90% under low-NOx conditions. Our results suggest that isoprene emission from the central African rainforest is much lower than estimated by the state-of-the-science MEGAN inventory.

The impact of local surface changes in Borneo on atmospheric composition at wider spatial scales: coastal processes, land-use change and air quality.

We present results from the OP3 campaign in Sabah during 2008 that allow us to study the impact of local emission changes over Borneo on atmospheric composition at the regional and wider scale. OP3 constituent data provide an important constraint on model performance. Treatment of boundary layer processes is highlighted as an important area of model uncertainty. Model studies of land-use change confirm earlier work, indicating that further changes to intensive oil palm agriculture in South East Asia, and the tropics in general, could have important impacts on air quality, with the biggest factor being the concomitant changes in NO(x) emissions. With the model scenarios used here, local increases in ozone of around 50 per cent could occur. We also report measurements of short-lived brominated compounds around Sabah suggesting that oceanic (and, especially, coastal) emission sources dominate locally. The concentration of bromine in short-lived halocarbons measured at the surface during OP3 amounted to about 7 ppt, setting an upper limit on the amount of these species that can reach the lower stratosphere.

HuR keeps an angiogenic switch on by stabilising mRNA of VEGF and COX-2 in tumour endothelium.

BACKGROUND: Tumour stromal cells differ from its normal counterpart. We have shown that tumour endothelial cells (TECs) isolated from tumour tissues are also abnormal. Furthermore, we found that mRNAs of vascular endothelial growth factor-A (VEGF-A) and cyclooxygenase-2 (COX-2) were upregulated in TECs. Vascular endothelial growth factor-A and COX-2 are angiogenic factors and their mRNAs contain an AU-rich element (ARE). AU-rich element-containing mRNAs are reportedly stabilised by Hu antigen R (HuR), which is exported to the cytoplasm. METHODS: Normal endothelial cell (NEC) and two types of TECs were isolated. We evaluated the correlation of HuR and accumulation of VEGF-A and COX-2 mRNAs in TECs and effects of HuR on biological phenotypes of TECs. RESULTS: The HuR protein was accumulated in the cytoplasm of TECs, but not in NECs. Vascular endothelial growth factor-A and COX-2 mRNA levels decreased due to HuR knockdown and it was shown that these ARE-mRNA were bound to HuR in TECs. Furthermore, HuR knockdown inhibited cell survival, random motility, tube formation, and Akt phosphorylation in TECs. CONCLUSION: Hu antigen R is associated with the upregulation of VEGF-A and COX-2 mRNA in TECs, and has an important role in keeping an angiogenic switch on, through activating angiogenic phenotype in tumour endothelium.

Glycogen synthase kinase-3beta and p38 phosphorylate cyclin D2 on Thr280 to trigger its ubiquitin/proteasome-dependent degradation in hematopoietic cells.

Cyclin D2 plays an important role in regulation of hematopoietic cell proliferation by cytokines and is implicated in oncogenesis of various hematopoietic malignancies. However, mechanisms regulating cyclin D2 stability and its expression level have remained to be known. Here, we demonstrate that interleukin-3 signaling stabilizes cyclin D2 by inhibition of glycogen synthase kinase-3beta (GSK3beta) through Janus kinase2-dependent activation of phosphatidylinositol 3'-kinase (PI3K)/Akt signaling pathway in hematopoietic 32Dcl3 cells. On the other hand, osmotic stress was shown to induce a rapid proteasomal degradation of cyclin D2, which was mediated by activation of p38. GSK3beta and p38 was demonstrated to phosphorylate cyclin D2 on Thr280 in vitro, while a cyclin D2 mutant with this residue substituted with Ala was found to be resistant to ubiquitination and proteasome-dependent degradation in 32Dcl3 cells. Inhibition of the PI3K pathway or induction of osmotic stress also caused a rapid proteasomal degradation of cyclin D2 in primary leukemic or myeloma cells. These results indicate that cyclin D2 expression in normal and malignant hematopoietic cells is regulated by ubiquitin/proteasome-dependent degradation that is triggered by Thr280 phosphorylation by GSK3beta or p38, which is induced by inhibition of the PI3K pathway or by osmotic stress, respectively.

Rottlerin synergistically enhances imatinib-induced apoptosis of BCR/ABL-expressing cells through its mitochondrial uncoupling effect independent of protein kinase C-delta.

Although the BCR/ABL tyrosine kinase inhibitor imatinib is highly effective for treatment of chronic myeloid leukemia (CML) and Philadelphia-chromosome positive acute lymphoblastic leukemia (ALL), relapse with emerging imatinib-resistance mutations in the BCR/ABL kinase domain poses a significant problem. Here, we demonstrate that rottlerin, a putative protein kinase C-delta (PKCdelta)-specific inhibitor, acts synergistically with imatinib to induce apoptosis of BCR/ABL-expressing K562 and Ton.B210 cells. However, rottlerin inhibited neither PKCdelta nor BCR/ABL in these cells. On the other hand, rottlerin, previously characterized also as a mitochondrial uncoupler, transiently but significantly reduced mitochondrial membrane potential and gradually induced mitochondrial membrane permeabilization. Moreover, two other mitochondrial uncouplers, FCCP and DNP, very similarly induced apoptosis of BCR/ABL-expressing cells in a synergistic manner with imatinib. Imatinib synergistically enhanced mitochondrial membrane permeabilization induced by mitochondrial uncouplers, which led to release of cytochrome c into the cytoplasm and activation of caspases-3 and -9. Rottlerin also enhanced the cytotoxic effect of imatinib in leukemic cells from patients with CML blast crisis and Ph-positive ALL or a cell line expressing the imatinib-resistant E255K BCR/ABL mutant. The present study indicates that rottlerin synergistically enhances imatinib-induced apoptosis through its mitochondrial uncoupling effect independent of PKCdelta and may contribute to the development of new treatment strategy to overcome the imatinib resistance and to cure the BCR/ABL expressing leukemias.

BCR/ABL and IL-3 activate Rap1 to stimulate the B-Raf/MEK/Erk and Akt signaling pathways and to regulate proliferation, apoptosis, and adhesion.

The Ras family small GTPase Rap1 is activated by hematopoietic cytokines, such as interleukin (IL)-3, to induce beta1 integrin-mediated cell adhesion or by the BCR/ABL fusion tyrosine kinase to stimulate the MEK/Erk signaling pathway. Here, we demonstrate that the abrogation of Rap1 activation by SPA-1, a Rap1-specific GAP, inhibits activation of B-Raf, MEK, Erk, and Akt in a murine hematopoietic cell line, Ton.B210, stimulated with IL-3 or inducibly expressing BCR/ABL. Furthermore, Rap1 inactivation had an inhibitory effects on proliferation and survival of Ton.B210 cells, which were more remarkable when cells were stimulated by BCR/ABL than by IL-3. Induction of BCR/ABL expression increased adhesion of Ton.B210 cells to fibronectin in a manner at least partly dependent on its kinase activity, and Rap1 inhibition by SPA-1 partially inhibited BCR/ABL-induced adhesion of cells. Thus, IL-3- or BCR/ABL-induced activation of Rap1 may play important roles in regulation of cell proliferation and survival through activation of the B-Raf/MEK/Erk and Akt signaling pathways and in induction of integrin-mediated cell adhesion. Furthermore, as compared with IL-3, BCR/ABL is more dependent on Rap1-mediated signaling to induce cell proliferation and survival and, thus, Rap1 may represent an attractive target for novel therapies for leukemias caused by BCR/ABL.

p38 MAP kinase plays a role in G2 checkpoint activation and inhibits apoptosis of human B cell lymphoma cells treated with etoposide.

p38 MAPK is mainly activated by stress stimuli and mediates signals that regulate various cellular responses, including cell-cycle progression and apoptosis, depending on cell types and stimuli. Here we examine the role of p38 in regulation of apoptosis and cell cycle checkpoint in Daudi B-cell lymphoma cells treated with the topoisomerase II inhibitor etoposide. Etoposide activated p38, inhibited the G2/M transition with the persistent inhibitory phosphorylation of Cdc2 on Tyr15, and caused apoptosis of Daudi cells. Inducible expression of a dominant negative p38alpha mutant in Daudi cells reduced the inhibition of Cdc2 as well as G2/M arrest and augmented apoptosis induced by etoposide. SB203580, a specific inhibitor of p38alpha and p38beta, similarly reduced the inhibitory phosphorylation of Cdc2 as well as G2/M arrest and augmented apoptosis of Daudi cells treated with etoposide. These results suggest that p38 plays a role in G2/M checkpoint activation through induction of the persistent inhibitory phosphorylation of Cdc2 and, thereby, inhibits apoptosis of Daudi cells treated with etoposide. The present study, thus, raises the possibility that p38 may represent a new target for sensitization of lymphoma cells to DNA-damaging chemotherapeutic agents.

Variable sequences in the long terminal repeat and Its downstream region of some of HIV Type 1 CRF01_AE recently distributing among Thai carriers.

Human immunodeficiency virus type 1 (HIV-1) proviral DNA sequences in and downstream of the 5' long terminal repeat (LTR) were compared among samples obtained from 13 HIV-1 CRF01_AE-infected individuals in Thailand from 1998 to 1999. Eleven individuals had highly conserved sequences compared with previously reported CRF01_AE viruses. However, T cell-specific factor (TCF)-1alpha motif, which is located just beside the 3' terminus of the nef sequence, was duplicated in 2 out of the 13 subjects, one of whom had also lost the 24 nucleotides next to the 3' of the primer-binding site. Thus, several characteristics of CRF01_AE LTR and gag-leader sequence were identified in some samples recently obtained in Thailand.

Low or no antibody responses to human immunodeficiency virus type 1 Nef in infected carriers with subtype E, in contrast to subtype B that showed antibodies preferentially recognizing subtype-specific Nef epitopes.

The viral accessory gene product Nef has been shown to play an important role in human immunodeficiency virus type 1 (HIV-1)-induced pathogenesis. Only little information is available regarding the differences in the host immune responses against Nef protein and its function in vivo among different subtypes of HIV-1. In the present study, we showed marked differences in the immune responses to Nef protein between subtypes B and E. The amino acid sequence in subtype E Nef showed 72% homology with that in subtype B. Most murine monoclonal antibodies obtained by immunization with subtype B or E Nef protein showed cross-reactivity with both Nef proteins (80 and 67%, respectively). Next, we focused on the immune responses among infected Japanese and Thai individuals. Subtyping of the individuals into B and E was carried out by enzyme-linked immunosorbent assay (ELISA) using synthetic peptides corresponding to the V3 loop representing the principal neutralizing domain. Most of the sera from these individuals reacted strongly with Gag p24 proteins derived from subtypes B and E at similar levels. However, the immune responses among these individuals to Nef protein were markedly different. Some subtype B-infected Japanese and Thai individuals (40 and 35%, respectively) showed higher levels of anti-Nef antibodies, although these antibodies preferentially recognized epitopes specific to subtype B. On the other hand, most of the subtype E-infected Japanese and Thai individuals showed low or no antibody responses to Nef proteins. Thus, immune responses to Nef were markedly different between subtypes B- and E-infected carriers, suggesting different function(s) for Nef in AIDS pathogenesis. Further, vaccine design must take into account the different subtypes of HIV-1.

Adenovirus is a key pathogen in hemorrhagic cystitis associated with bone marrow transplantation.

Late-onset hemorrhagic cystitis (HC) is a well-known complication of bone marrow transplantation (BMT) that is mainly attributed to infection with BK virus (BKV) and adenovirus (AdV). From 1986 through 1998, 282 patients underwent BMT, and 45 of them developed HC. Urine samples tested positive for AdV in 26 patients, of which 22 showed virus type 11. Among patients who underwent allogeneic BMT, logistic regression analysis revealed acute graft-versus-host disease (grade, > or = 2) to be the most significant predictive factor for HC (P < .0001). In addition, a total of 193 urine samples regularly obtained from 26 consecutive patients who underwent allogeneic BMT were examined for BKV, JC virus (JCV), and AdV by means of polymerase chain reaction. Of patients without HC, approximately 30% of the specimens tested positive for BKV (58 samples) and JCV (55 samples), whereas 5 (3%) tested positive for AdV. Of the 3 samples obtained from patients with HC, the numbers of positive results for BKV, JCV, and AdV were 3, 1, and 1, respectively; the numbers of positive results increased to 14 of 17, 9 of 17, and 10 of 17, respectively, when we added another 14 samples obtained from 14 patients with HC (P < .0001, P = .026, and P < .0001, respectively). In conclusion, there was significant correlation between AdV and HC in the patients we studied.

Sub-systems for optical frequency measurements: application to the 282-nm (199)Hg(+) transition and the 657-nm Ca line.

We are developing laser frequency measurement technologies that should allow us to construct an optical frequency synthesis system capable of measuring optical frequencies with a precision limited by the atomic frequency standards. The system will be used to interconnect and compare new advanced optical-frequency references (such as Ca, Hg(+ ), and others) and eventually to connect these references to the Cs primary frequency standard. The approach we are taking is to subdivide optical frequency intervals into smaller and smaller pieces until we are able to use standard electronic-frequency-measurement technology to measure the smallest interval.

Differences of IgG and IgM antibodies to phospholipids and APTT among non-pregnant and pregnant women.

OBJECTIVE: The objective of our study was to assess the difference in IgG and IgM antibodies to cardiolipin(CL), phosphatidylserine(PS), and APTT among non-pregnant and pregnant women. METHODS: IgG and IgM antibodies to CL and PS among 102 healthy non-pregnant women and 154 healthy pregnant women were measured by an ELISA. The activated partial thromboplastin time(APTT) was measured in 67 healthy non-pregnant women, in 67 healthy women at 10-14 weeks of gestation, and in 67 healthy women at 30-32 weeks of gestation. We compared the titer of +2SD in each group. RESULTS: The titers +2SD of IgG antibodies to CL and PS in pregnant women were lower than in non-pregnant women (p < 0.05), whereas the values of the IgM antibody to CL and PS were the same in pregnant and non-pregnant women. The APTT in pregnant women was significantly shorter than in non-pregnant women (p = 0.0001). CONCLUSION: Standard criteria for the positivity of the IgG antibody to CL and PS and the prolongation of APTT in pregnancy should employ the values of normal pregnant women rather than those of non-pregnant women.

Two M-components in a single cell lineage in a patient with a dual isotype secretory B-cell tumour.

We describe a case of Waldenström's macroglobulinaemia with two M-components (IgM and IgG) with the same lambda light chain. Southern blot analysis of bone marrow cells showed rearrangements of immunoglobulin heavy and lambda light chain genes. Sequencing of the complementarity determining region 3 of the two lambda and mu transcripts showed 100% homology. Immunofluorescence study showed that most cells stained for both IgG and IgM. These findings indicated that a single population of cells was expressing two isotypic variants of IgG and IgM, as the genes responsible for production of both components had the same origin.

[Plasma cell leukemia with amyloid deposition and osteogenetic change at the site of an extramedullary plasmacytoma].

A 49-year-old man was admitted with swelling in the left lower extremity, and a mass in the left lower abdomen. Laboratory findings showed an increased WBC of 15,000/microliter with 41% plasma cells, and immunoglobulin (Ig) A of 2,557mg/dl with a monoclonal component. A roentgenogram and computed tomograph of the abdomen revealed that a 5 x 10 cm mass with calcification located in the iliopsoas muscle. Plasma cell leukemia with extramedullary plasmacytoma was diagnosed, and the patient was treated with high-dose dexamethasone (40 mg/day for 4 days), resulting in a good response with the disappearance of plasma cells in peripheral blood and a marked decrease in serum Ig A. However, the patient's condition deteriorated in spite of various treatments, and he died of heart failure 5 months after admission. With informed consent from relatives, a necropsy was performed and infiltration of plasma cells in the mass in the iliopsoas muscle was noted. We reported this case because plasma cell leukemia with amyloid deposition and osteogenesis at the site of extramedullary plasmacytoma is very rare.