16 results on '"Rongqing Guo"'
Search Results
2. Supplementary Figures from Acquired Resistance and Clonal Evolution in Melanoma during BRAF Inhibitor Therapy
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Roger S. Lo, Antoni Ribas, Georgina V. Long, Nicolas van Baren, Jeffrey A. Sosman, John A. Glaspy, Bartosz Chmielowski, Richard F. Kefford, Mark C. Kelley, Kimberly B. Dahlman, Douglas B. Johnson, Rongqing Guo, Thinle Chodon, Gatien Moriceau, Richard C. Koya, Aayoung Hong, Xiangju Kong, Willy Hugo, and Hubing Shi
- Abstract
PDF file 6308K, This includes all supplementary figures except S2 and contains additional clinical data, sequence and copy number analysis as well as immunohistochemical and functional studies
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- 2023
3. Supplementary Figure S2 from Acquired Resistance and Clonal Evolution in Melanoma during BRAF Inhibitor Therapy
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Roger S. Lo, Antoni Ribas, Georgina V. Long, Nicolas van Baren, Jeffrey A. Sosman, John A. Glaspy, Bartosz Chmielowski, Richard F. Kefford, Mark C. Kelley, Kimberly B. Dahlman, Douglas B. Johnson, Rongqing Guo, Thinle Chodon, Gatien Moriceau, Richard C. Koya, Aayoung Hong, Xiangju Kong, Willy Hugo, and Hubing Shi
- Abstract
PDF file 8842K, Supplementary Figure S2 contains Sanger re-sequencing to estimate the specificity of WES
- Published
- 2023
4. Acute Renal Failure in Endotoxemia is Dependent on Caspase Activation
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Ying Wang, Richard J. Quigg, Patrick N. Cunningham, Andrew W. Minto, and Rongqing Guo
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Lipopolysaccharides ,Male ,Nephrology ,medicine.medical_specialty ,Programmed cell death ,Apoptosis ,Inflammation ,Cysteine Proteinase Inhibitors ,DNA laddering ,Kidney ,Amino Acid Chloromethyl Ketones ,Mice ,Internal medicine ,medicine ,Animals ,Caspase ,biology ,business.industry ,General Medicine ,Acute Kidney Injury ,medicine.disease ,Endotoxemia ,Enzyme Activation ,Mice, Inbred C57BL ,medicine.anatomical_structure ,Caspases ,Immunology ,biology.protein ,Cancer research ,medicine.symptom ,business ,Kidney disease - Abstract
In previous work, it was demonstrated that apoptosis occurs in the kidney during LPS-induced acute renal failure (ARF). However, the relative importance of apoptosis in LPS-induced ARF remained unproven. Because the caspase enzyme cascade is responsible for carrying out apoptosis, it was hypothesized that treatment with a caspase inhibitor would protect mice from LPS-induced ARF. C57BL/6 mice received an injection of LPS and were treated with either the broad-spectrum caspase inhibitor z-VAD-fmk or vehicle and compared with unmanipulated mice. LPS induced a significant increase in caspase-3 activity in vehicle-treated mice, which was significantly inhibited by z-VAD. Mice that were treated with z-VAD were protected from ARF and demonstrated significantly less apoptosis as measured by both terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling staining and DNA laddering. Although apoptosis is classically described as a noninflammatory process, z-VAD treatment significantly attenuated multiple markers of inflammation, such as renal neutrophil infiltration and renal expression of the neutrophil chemotactic factor macrophage inflammatory protein-2. Thus, caspase inhibition may protect against LPS-induced ARF not only by preventing apoptotic cell death but also by inhibiting inflammation. These data raise the possibility that apoptotic kidney cells may actually be a source of this local inflammation, contributing to subsequent nonapoptotic renal injury.
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- 2004
5. Role of Toll-Like Receptor 4 in Endotoxin-Induced Acute Renal Failure
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Richard J. Quigg, Gang He, Ying Wang, Rongqing Guo, and Patrick N. Cunningham
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Lipopolysaccharides ,Male ,medicine.medical_specialty ,Immunology ,Apoptosis ,Receptors, Cell Surface ,DNA laddering ,Kidney ,Mice ,Species Specificity ,Internal medicine ,medicine ,Animals ,Immunology and Allergy ,Receptor ,Blood urea nitrogen ,Mice, Inbred C3H ,Toll-like receptor ,Membrane Glycoproteins ,business.industry ,Toll-Like Receptors ,Acute Kidney Injury ,Kidney Transplantation ,Immunity, Innate ,Mice, Inbred C57BL ,Toll-Like Receptor 4 ,Endocrinology ,medicine.anatomical_structure ,Neutrophil Infiltration ,ADP-Ribosylation Factor 6 ,TLR4 ,lipids (amino acids, peptides, and proteins) ,Tumor necrosis factor alpha ,business ,Injections, Intraperitoneal - Abstract
Toll-like receptor 4 (TLR4) is present on monocytes and other cell types, and mediates inflammatory events such as the release of TNF after exposure to LPS. C3H/HeJ mice are resistant to LPS-induced mortality, due to a naturally occurring mutation in TLR4. We therefore hypothesized that LPS-induced acute renal failure (ARF) requires systemic TNF release triggered by LPS acting on extrarenal TLR4. We injected C3H/HeJ mice and C3H/HeOuJ controls with 0.25 mg of LPS, and sacrificed them 6 h later for analysis of blood urea nitrogen (BUN) and kidney tissue (n = 8 per group). In contrast to C3H/HeOuJ controls, C3H/HeJ mice were completely resistant to LPS-induced ARF (6-h BUN of 32.3 ± 1.1 vs 61.7 ± 5.6 mg/dl). C3H/HeJ mice released no TNF into the circulation at 2 h (0.00 vs 1.24 ± 0.16 ng/ml), had less renal neutrophil infiltration (6.4 ± 1.0 vs 11.4 ± 1.3 neutrophils per high power field), and less renal apoptosis, as assessed by DNA laddering. Transplant studies showed that C3H/HeJ recipients of wild-type kidneys (n = 9) were protected from LPS-induced ARF, while wild-type recipients of C3H/HeJ kidneys (n = 11) developed severe LPS-induced ARF (24-h BUN 44.0 ± 4.1 vs 112.1 ± 20.0 mg/dl). These experiments support our hypothesis that LPS acts on extrarenal TLR4, thereby leading to systemic TNF release and subsequent ARF. Renal neutrophil infiltration and renal cell apoptosis are potential mechanisms by which endotoxemia leads to functional ARF.
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- 2004
6. Lack of Insulin-Like Growth Factor I Exaggerates the Effect of Calcium Deficiency on Bone Accretion in Mice
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Apurva K. Srivastava, Yuji Kasukawa, Yousef G. Amaar, David J. Baylink, Rongqing Guo, Jon E. Wergedal, and Subburaman Mohan
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medicine.medical_specialty ,Ratón ,medicine.medical_treatment ,chemistry.chemical_element ,Calcium ,Kidney ,Mice ,Insulin-like growth factor ,Absorptiometry, Photon ,Endocrinology ,Bone Density ,Osteogenesis ,Internal medicine ,medicine ,Animals ,Femur ,Sexual Maturation ,Tibia ,Bone Resorption ,Insulin-Like Growth Factor I ,Vitamin D ,Quantitative computed tomography ,Mice, Knockout ,Endosteum ,Bone mineral ,Periosteum ,medicine.diagnostic_test ,Chemistry ,Body Weight ,medicine.anatomical_structure ,Parathyroid Hormone ,Growth Hormone ,Receptors, Calcitriol ,Tomography, X-Ray Computed - Abstract
Recent studies provide evidence that the GH/IGF-I axis plays a critical role in the regulation of bone accretion that occurs during puberty and that the peak bone mineral density (BMD) is dependent on the amount of dietary calcium intake during the active growth phases. To evaluate whether IGF-I deficiency exaggerates the effect of calcium deficiency on bone accretion during active growth phases, IGF-I knockout (KO) and wild-type (WT) mice were fed with low calcium (0.01%) or normal calcium (0.6%) for 2 wk during the pubertal growth phase and were labeled with tetracycline. The low calcium diet caused significant decreases in endosteal bone formation parameters and a much greater increase in the resorbing surface of both the endosteum and periosteum of the tibia of IGF-I KO mice compared with WT mice. Accordingly, femur BMD measured by dual energy x-ray absorptiometry or peripheral quantitative computed tomography increased significantly in IGF-I WT mice fed the low calcium diet, but not in IGF-I KO mice. IGF-I-deficient mice fed the normal calcium diet showed elevated PTH levels, decreased serum 1,25-dihydroxyvitamin D and serum calcium levels at baseline. Serum calcium changes due to calcium deficiency were greater in IGF-I KO mice compared with WT mice. PTH levels were 7-fold higher in IGF-I KO mice fed normal calcium compared with WT mice, which was further elevated in mice fed the low calcium diet. Treatment of IGF-I-deficient lit/lit mice with GH decreased the serum PTH level by 70% (P < 0.01). Based on these and past findings, we conclude that: 1) IGF-I deficiency exaggerates the negative effects of calcium deficiency on bone accretion; and 2) IGF-I deficiency may lead to 1,25-dihydroxyvitamin D deficiency and elevated PTH levels even under normal calcium diet.
- Published
- 2003
7. Insulin-Like Growth Factor Regulates Peak Bone Mineral Density in Mice by Both Growth Hormone-Dependent and -Independent Mechanisms
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Leah Rea Donahue, Charmaine Richman, Jon E. Wergedal, Subburaman Mohan, Rongqing Guo, Yousef G. Amaar, and David J. Baylink
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Male ,medicine.medical_specialty ,Bone density ,medicine.medical_treatment ,Osteocalcin ,Article ,Growth hormone deficiency ,Mice ,Insulin-like growth factor ,Absorptiometry, Photon ,Endocrinology ,Bone Density ,Insulin-Like Growth Factor II ,Internal medicine ,medicine ,Animals ,Femur ,Sexual Maturation ,Insulin-Like Growth Factor I ,Quantitative computed tomography ,Mice, Knockout ,Bone mineral ,Bone growth ,Sex Characteristics ,biology ,medicine.diagnostic_test ,Chemistry ,Growth factor ,Body Weight ,Organ Size ,medicine.disease ,Mice, Inbred C57BL ,Growth Hormone ,Mutation ,biology.protein ,Female ,Tomography, X-Ray Computed - Abstract
To evaluate the relative contribution of the GH/IGF axis to the development of peak bone mineral density (BMD), we measured skeletal changes in IGF-I knockout (KO), IGF-II KO, and GH-deficient lit/lit mice and their corresponding control mice at d 23 (prepubertal), 31 (pubertal), and 56 (postpubertal) in the entire femur by dual energy x-ray absorptiometry and in the mid-diaphysis by peripheral quantitative computed tomography. Lack of growth factors resulted in different degrees of failure of skeletal growth depending on the growth period and the growth factor involved. At d 23, femoral length, size, and BMD were reduced by 25–40%, 15–17%, and 8–10%, respectively, in mice deficient in IGF-I, IGF-II, and GH compared with the control mice. During puberty, BMD increased by 40% in control mice and by 15% in IGF-II KO and GH-deficient mice, whereas it did not increase in the IGF-I KO mice. Disruption of IGF-I, but not IGF-II, completely prevented the periosteal expansion that occurs during puberty, whereas it was reduced by 50% in GH-deficient mice. At d 56, femoral length, size, and BMD were reduced by 40–55%, 11–18%, and 25–32%, respectively, in mice deficient in IGF-I, IGF-II, and GH compared with the control mice. Our data demonstrate that: 1) mice deficient in IGF-I exhibit a greater impairment in bone accretion than mice deficient in IGF-II or GH; 2) GH/IGF-I, but not IGF-II, is critical for puberty-induced bone growth; and 3) IGF-I effects on bone accretion during prepuberty are mediated predominantly via mechanisms independent of GH, whereas during puberty they are mediated via both GH-dependent and GH-independent mechanisms.
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- 2003
8. Acquired resistance and clonal evolution in melanoma during BRAF inhibitor therapy
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Mark C. Kelley, Jeffrey A. Sosman, Antoni Ribas, Thinle Chodon, Gatien Moriceau, Kimberly B. Dahlman, Willy Hugo, John A. Glaspy, Xiangju Kong, Richard F. Kefford, Georgina V. Long, Roger S. Lo, Nicolas van Baren, Hubing Shi, Bartosz Chmielowski, Rongqing Guo, Richard C. Koya, Aayoung Hong, and Douglas B. Johnson
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Male ,Skin Neoplasms ,Indoles ,Mutant ,Drug Resistance ,Drug resistance ,Somatic evolution in cancer ,Phosphatidylinositol 3-Kinases ,Oximes ,80 and over ,Vemurafenib ,Melanoma ,Cancer ,Sulfonamides ,Tumor ,Imidazoles ,Middle Aged ,Oncology ,5.1 Pharmaceuticals ,Female ,Mitogen-Activated Protein Kinases ,Development of treatments and therapeutic interventions ,medicine.drug ,Biotechnology ,Proto-Oncogene Proteins B-raf ,Adult ,Oncology and Carcinogenesis ,Antineoplastic Agents ,Biology ,Cell Line ,Clonal Evolution ,Clinical Research ,medicine ,Genetics ,Humans ,Protein kinase A ,neoplasms ,Protein Kinase Inhibitors ,Aged ,Alternative splicing ,Human Genome ,PTEN Phosphohydrolase ,medicine.disease ,Good Health and Well Being ,Cell culture ,Cancer research ,ras Proteins ,Neoplasm ,Proto-Oncogene Proteins c-akt - Abstract
BRAF inhibitors elicit rapid antitumor responses in the majority of patients with BRAFV600-mutant melanoma, but acquired drug resistance is almost universal. We sought to identify the core resistance pathways and the extent of tumor heterogeneity during disease progression. We show that mitogen-activated protein kinase reactivation mechanisms were detected among 70% of disease-progressive tissues, with RAS mutations, mutant BRAF amplification, and alternative splicing being most common. We also detected PI3K–PTEN–AKT–upregulating genetic alterations among 22% of progressive melanomas. Distinct molecular lesions in both core drug escape pathways were commonly detected concurrently in the same tumor or among multiple tumors from the same patient. Beyond harboring extensively heterogeneous resistance mechanisms, melanoma regrowth emerging from BRAF inhibitor selection displayed branched evolution marked by altered mutational spectra/signatures and increased fitness. Thus, melanoma genomic heterogeneity contributes significantly to BRAF inhibitor treatment failure, implying upfront, cotargeting of two core pathways as an essential strategy for durable responses. Significance: This study provides critical insights into how human BRAF-mutant melanoma, a malignancy with marked mutational burden, escapes from BRAF inhibitors. Understanding the core resistance pathways as well as tumor heterogeneity, fitness, and mutational patterns, which emerge under drug selection, lays a foundation to rationalize clinical studies and investigate mechanisms of disease progression. Cancer Discov; 4(1); 80–93. ©2013 AACR. See related commentary by Solit and Rosen, p. 27 This article is highlighted in the In This Issue feature, p. 1
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- 2014
9. Modeling and simulation of driving system for electric vehicle based on fuzzy control strategy
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Man Yu, Rongqing Guo, Yilin He, and Xuan Zhao
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Engineering ,business.product_category ,business.industry ,Direct current ,Control engineering ,Fuzzy control system ,DC motor ,Modeling and simulation ,Software ,Robustness (computer science) ,Control theory ,Electric vehicle ,Balance equation ,business - Abstract
The establishment of mathematical model of electric vehicle(EV) driving system combines balance equation of vehicle movement with equation of mechanical characteristics of direct current (DC) motor. Fuzzy PI control strategy optimizes the model and simulates the model with Simulink software. Simulation results show that the mathematical model of EV driving system can reflect operating condition of the vehicle factually and accurately. Fuzzy PI control strategy optimizes the control of driving system, at the same time makes simulation speed track the required speed accordingly. The model has strong robustness and is applicable to the simulation of EV driving system.
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- 2011
10. TNF induces caspase-dependent inflammation in renal endothelial cells through a Rho- and myosin light chain kinase-dependent mechanism
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Quan Wang, Peili Chen, Rongqing Guo, Patrick N. Cunningham, and Xiaoyan Wu
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rho GTP-Binding Proteins ,Myosin light-chain kinase ,Myosin Light Chains ,Time Factors ,Physiology ,medicine.medical_treatment ,Active Transport, Cell Nucleus ,Vascular Cell Adhesion Molecule-1 ,Inflammation ,Apoptosis ,Cysteine Proteinase Inhibitors ,Kidney ,Pathogenesis ,Mice ,NF-KappaB Inhibitor alpha ,medicine ,Cell Adhesion ,Animals ,Phosphorylation ,Myosin-Light-Chain Kinase ,Protein Kinase Inhibitors ,Caspase ,Cells, Cultured ,Caspase 8 ,Nephritis ,biology ,Tumor Necrosis Factor-alpha ,Acute kidney injury ,Transcription Factor RelA ,Endothelial Cells ,medicine.disease ,Intercellular Adhesion Molecule-1 ,Caspase Inhibitors ,Enzyme Activation ,Mice, Inbred C57BL ,Cytokine ,medicine.anatomical_structure ,Neutrophil Infiltration ,Immunology ,Cancer research ,biology.protein ,Tumor necrosis factor alpha ,I-kappa B Proteins ,medicine.symptom ,rhoA GTP-Binding Protein ,Signal Transduction - Abstract
The pathogenesis of LPS-induced acute kidney injury (AKI) requires signaling through tumor necrosis factor-alpha (TNF) receptor 1 (TNFR1), which within the kidney is primarily located in the endothelium. We showed previously that caspase inhibition protected mice against LPS-induced AKI and in parallel significantly inhibited LPS-induced renal inflammation. Therefore we hypothesized that caspase activation amplifies TNF-induced inflammation in renal endothelial cells (ECs). In cultured renal ECs, TNF induced apoptosis through a caspase-8-dependent pathway. TNF caused translocation of the p65 subunit of NF-kappaB to the nucleus, resulting in upregulation of inflammatory markers such as adhesion molecules ICAM-1 and VCAM-1. However, the broad-spectrum caspase inhibitor Boc-d-fmk reduced NF-kB activation as assessed by gel shift assay, reduced phosphorylation of subunit IkappaBalpha, and significantly inhibited TNF-induced expression of ICAM-1 and VCAM-1 as assessed by both real-time PCR and flow cytometry. Broad-spectrum caspase inhibition markedly inhibited neutrophil adherence to the TNF-activated endothelial monolayer, supporting the functional significance of this effect. Specific inhibitors of caspases-8 and -3, but not of caspase-1, reduced TNF-induced NF-kappaB activation. Caspase inhibition also reduced TNF-induced myosin light chain (MLC)-2 phosphorylation, and activation of upstream regulator RhoA. Consistent with this, MLC kinase (MLCK) inhibitor ML-7 reduced TNF-induced NF-kappaB activation. Thus caspase activation influences NF-kappaB signaling via its affect on cytoskeletal changes occurring through RhoA and MLCK pathways. These cell culture experiments support a role for caspase activation in TNF-induced inflammation in the renal endothelium, a key event in LPS-induced AKI.
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- 2009
11. Evidence that sensitivity to growth hormone (GH) is growth period and tissue type dependent: studies in GH-deficient lit/lit mice
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Yuji Kasukawa, Subburaman Mohan, David J. Baylink, and Rongqing Guo
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Male ,medicine.medical_specialty ,Bone density ,Ratón ,Adipose tissue ,Biology ,Article ,Mice ,Endocrinology ,Absorptiometry, Photon ,Bone Density ,Internal medicine ,medicine ,Animals ,Femur ,Quantitative computed tomography ,Insulin-Like Growth Factor I ,Bone mineral ,medicine.diagnostic_test ,Body Weight ,Receptors, Somatotropin ,Mice, Mutant Strains ,Mice, Inbred C57BL ,Somatropin ,Adipose Tissue ,Organ Specificity ,Growth Hormone ,Lean body mass ,Female - Abstract
We previously found that the magnitude of skeletal deficits caused by GH deficiency varied during different growth periods. To test the hypothesis that the sensitivity to GH is growth period dependent, we treated GH-deficient lit/lit mice with GH (4 mg/kg body weight·d) or vehicle during the prepubertal and pubertal (d 7–34), pubertal (d 23–34), postpubertal (d 42–55), and adult (d 204–217) periods and evaluated GH effects on the musculoskeletal system by dual energy x-ray absorptiometry (DEXA) and peripheral quantitative computed tomography. GH treatment during different periods significantly increased total body bone mineral content, bone mineral density (BMD), bone area, and lean body mass and decreased percentage of fat compared with vehicle; however, the magnitude of change varied markedly depending on the treatment period. For example, the increase in total body BMD was significantly (P < 0.01) greater when GH was administered between d 42–55 (15%) compared with pubertal (8%) or adult (7.7%) periods, whereas the net loss in percentage of body fat was greatest (−56%) when GH was administered between d 204 and 216 and least (−27%) when GH was administered between d 7 and 35. To determine whether GH-induced anabolic effects on the musculoskeletal system are maintained after GH withdrawal, we performed DEXA measurements 3–7 wk after stopping GH treatment. The increases in total body bone mineral content, BMD, and lean body mass, but not the decrease in body fat, were sustained after GH withdrawal. Our findings demonstrate that the sensitivity to GH in target tissues is growth period and tissue type dependent and that continuous GH treatment is necessary to maintain body fat loss but not BMD gain during a 3–7 wk follow-up.
- Published
- 2003
12. Physical localization of rRNA genes by two-colour fluorescent in-situ hybridization and sequence analysis of the 5S rRNA gene in Phalaris coerulescens
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Carsten Pedersen, D. L. Hayman, Xinmin Li, Rongqing Guo, and Peter Langridge
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Genetics ,Secondary constriction ,Base Sequence ,DNA, Plant ,Sequence analysis ,Molecular Sequence Data ,RNA, Ribosomal, 5S ,Chromosome ,Karyotype ,Locus (genetics) ,Hordeum ,General Medicine ,Ribosomal RNA ,Biology ,Genes, Plant ,Poaceae ,Molecular biology ,DNA, Ribosomal ,Sequence Homology, Nucleic Acid ,Nucleolus organizer region ,Sequence Alignment ,In Situ Hybridization, Fluorescence ,Genomic organization - Abstract
The 18S-5.8S-26S rDNA and 5s rDNA loci have been mapped physically by fluorescent in-situ hybridization to the chromosomes of Phalaris coerulescens. The biotin-labelled heterologous 18S-5.8S-26S rRNA probe (pTa71) detected one locus, which corresponded to the secondary constriction (nucleolar organizer) on the long arm of the satellited chromosome II. The homologous 5s rDNA probe (Bam2.12) detected two pairs of 5s rRNA gene clusters which were localized at two different non-satellited chromosomes, one near the telomere on the short arm of the chromosome I, which is the largest chromosome of the complement, and the other about 42 % out on the long arm of the chromosome III. A Bam HI fragment, containing the 5s rRNA gene, has been isolated and characterized. The 5s rDNA repeat unit is 309 bp in length, consisting of 121 bp highly conserved coding region and 188 bp variable spacer region. The karyotype of Phalaris coerulescens is characterized by the similar size of chromosomes within the group 2, group 3, or group 4. This study represents the first step towards the understanding the genome organization of Phalaris coerulescens and provides reliable markers for chromosome identification in this grass, an important species as a model system for the study of self-incompatibility in grasses.
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- 1997
13. Modeling and simulation of driving system for electric vehicle based on fuzzy control strategy.
- Author
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Rongqing Guo, Xuan Zhao, Man Yu, and Yilin He
- Published
- 2011
- Full Text
- View/download PDF
14. TNF induces caspase-dependent inflammation in renal endothelial cells through a Rho- and myosin light chain kinase-dependent mechanism.
- Author
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Xiaoyan Wu, Rongqing Guo, Peili Chen, Quan Wang, and Cunningham, Patrick N.
- Subjects
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TUMOR necrosis factors , *KIDNEY injuries , *INFLAMMATION , *ENDOTHELIUM , *MYOSIN , *PHOSPHORYLATION , *CELL culture - Abstract
The pathogenesis of LPS-induced acute kidney injury (AKI) requires signaling through tumor necrosis factor-α (TNF) receptor I (TNFR I), which within the kidney is primarily located in the endothelium. We showed previously that caspase inhibition protected mice against LPS-induced AKI and in parallel significantly inhibited LPS-induced renal inflammation. Therefore we hypothesized that caspase activation amplifies TNF-induced inflammation in renal endothelial cells (ECs). In cultured renal ECs, TNF induced apoptosis through a caspase-8-dependent pathway. TNF caused translocation of the p65 subunit of NF-κB to the nucleus, resulting in upregulation of inflammatory markers such as adhesion molecules ICAMI and VCAM1. However, the broadspectrum caspase inhibitor Boc-D-fmk reduced NF-κB activation as assessed by gel shift assay, reduced phosphorylation of subunit IκBα, and significantly inhibited TNF-induced expression of ICAM1 and VCAM-1 as assessed by both real-time PCR and flow cytometry. Broad-spectrum caspase inhibition markedly inhibited neutrophil adherence to the TNF-activated endothelial monolayer, supporting the functional significance of this effect. Specific inhibitors of caspases-8 and -3, but not of caspaseI, reduced TNF-induced NF-κB activation. Caspase inhibition also reduced TNF-induced myosin light chain (MLC)-2 phosphorylation, and activation of upstream regulator RhoA. Consistent with this, MLC kinase (MLCK) inhibitor ML-7 reduced TNF-induced NF-κB activation. Thus caspase activation influences NF-κB signaling via its affect on cytoskeletal changes occurring through RhoA and MLCK pathways. These cell culture experiments support a role for caspase activation in TNF-induced inflammation in the renal endothelium, a key event in LPS-induced AKI. [ABSTRACT FROM AUTHOR]
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- 2009
- Full Text
- View/download PDF
15. The role of ICAM- 1 in endotoxin-induced acute renal failure.
- Author
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Xiaoyan Wu, Rongqing Guo, Ying Wang, and Cunningham, Patrick N.
- Subjects
- *
ACUTE kidney failure , *KIDNEY diseases , *SEPSIS , *TUMOR necrosis factors , *INFLAMMATORY mediators , *GLYCOPROTEINS - Abstract
The pathogenesis of acute renal failure (ARF) occurring during the course of sepsis is incompletely understood. Intercellular adhesion molecule-I (ICAM-I) is a key cell adhesion molecule upregulated by LPS, which binds to the integrins CDI 1a/CD18 and CD1 lb/CD18 present on the surface of leukocytes. We hypothesized that ICAM-l facilitates renal injury in LPS-induced ARF. To test this, three groups of mice (n 8 per group) were injected intraperitoneally with 6 mg/kg LPS: 1) normal C57BL/6 mice, 2) mice with a targeted deficiency of ICAM- 1 (ICAM- 1-/-), and 3) mice expressing very low levels of CD18 (CD18-def). ICAM- 1 -/- mice were significantly resistant to LPS-mediated ARF, as opposed to CD18-def mice, which developed severe ARF, as did wild-type controls (48 h blood urea nitrogen 143 ± 31.5, 70.8 ± 24.4, and 185 ± 16.6 mg/dl in wild-type, ICAM- 1 -/-, and CDI 8-def mice, respectively, P < 0.05). At death, ICAM-1-/- mice had significantly less renal neutrophil infiltration than the other two groups, as well as less histological tubular injury. Depletion of neutrophils with mAb Gr-1 led to a profound exaggeration of tumor necrosis factor (TNF) release and high mortality, but neutrophil-depleted mice receiving 10-fold less LPS were protected against ARF despite TNF release similar to what is normally associated with LPS-induced ARF. LPS caused a significant increase in renal expression of chemokines; however, this increase was significantly exaggerated in CD18-def mice, which may account for their lack of protection. In conclusion, these data show that ICAM- 1 plays a key role in LPS-induced ARF. [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
- View/download PDF
16. Effect of Four Nitrogen Compounds on Nodulation and Nitrogen Fixation in Faba Bean, White Lupin and Medic Plants
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J. H. Silsbury, R. D. Graham, and Rongqing Guo
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Nodule (geology) ,biology ,food and beverages ,Nitrogenase ,chemistry.chemical_element ,Plant Science ,engineering.material ,biology.organism_classification ,Nitrogen ,Vicia faba ,Horticulture ,chemistry.chemical_compound ,Lupinus ,Agronomy ,chemistry ,engineering ,Nitrogen fixation ,Urea ,Ammonium ,Agronomy and Crop Science - Abstract
A pot experiment with sand as a rooting medium was conducted to investigate the effect of four different nitrogen sources (urea, nitrate, ammonium, nitrate + ammonium) at two concentrations (5 and 10 mM nitrogen) on nodulation and nitrogen fixation in faba bean (Vicia faba L. cv. Fiord), white lupin (Lupinus albus L.) and medic (Medicago rugosa Desr. cv. Paraponto). Results showed that all nitrogen forms were able to suppress nodule formation, nodule growth and nitrogenase activity, measured by acetylene reduction (AR) in all species studied, and the higher concentration had a stronger depressive effect than the lower level. Medic was inhibited most in terms of number of active nodules and AR activity per plant. Among the nitrogen forms, the suppression by NH4Cl was the most severe on nodulation causing the lowest nodule number and nodule weight, and on AR activity in all crops, while urea at 5 mM level seemed to be the least inhibitory. The depressive effect on AR was mainly due to the depressive effect on nodule formation and nodule growth, rather than to a direct influence on nodule specific activity.
- Published
- 1992
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