23 results on '"Ren RX"'
Search Results
2. [Progressive necrotizing xanthogranuloma in both eyes: a case report].
- Author
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Yang WY, Chen H, Ren RX, Xie Y, Wang JH, Wu S, and Ji M
- Subjects
- Humans, Male, Middle Aged, Lymphoma, Mantle-Cell pathology, Lymphoma, Mantle-Cell drug therapy, Rituximab therapeutic use, Necrobiotic Xanthogranuloma diagnosis
- Abstract
A 55-year-old male patient presenting with 6 months of bilateral difficulty in eye opening was referred to the ophthalmology department. Upon examination, multiple yellowish tumor-like plaques and nodules were observed on the eyelids and chest of the patient, accompanied by keratitis and iridocyclitis. Histopathological examination of the skin lesions on the chest revealed dermal xanthomatous granulomas with progressive necrosis. Bone marrow biopsy showed mantle cell lymphoma. Based on the medical history, the diagnosis of progressive necrotizing xanthogranuloma with mantle cell lymphoma was confirmed. After 6 months of treatment with bendamustine combined with rituximab, there was partial alleviation of ocular symptoms in the patient.
- Published
- 2024
- Full Text
- View/download PDF
3. Hepatic NCoR1 deletion exacerbates alcohol-induced liver injury in mice by promoting CCL2-mediated monocyte-derived macrophage infiltration.
- Author
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Yin F, Wu MM, Wei XL, Ren RX, Liu MH, Chen CQ, Yang L, Xie RQ, Jiang SY, Wang XF, and Wang H
- Subjects
- Animals, Chemokines metabolism, Disease Models, Animal, Epigenesis, Genetic, Ethanol toxicity, Hepatocytes metabolism, Inflammation metabolism, Ligands, Liver metabolism, Macrophages metabolism, Mice, Mice, Knockout, Nuclear Receptor Co-Repressor 1 genetics, Nuclear Receptor Co-Repressor 1 metabolism, Chemical and Drug Induced Liver Injury, Chronic, Fatty Liver, Liver Diseases, Alcoholic pathology
- Abstract
Nuclear receptor corepressor 1 (NCoR1) is a corepressor of the epigenetic regulation of gene transcription that has important functions in metabolism and inflammation, but little is known about its role in alcohol-associated liver disease (ALD). In this study, we developed mice with hepatocyte-specific NCoR1 knockout (NCoR1
Hep-/- ) using the albumin-Cre/LoxP system and investigated the role of NCoR1 in the pathogenesis of ALD and the underlying mechanisms. The traditional alcohol feeding model and NIAAA model of ALD were both established in wild-type and NCoR1Hep-/- mice. We showed that after ALD was established, NCoR1Hep-/- mice had worse liver injury but less steatosis than wild-type mice. We demonstrated that hepatocyte-specific loss of NCoR1 attenuated liver steatosis by promoting fatty acid oxidation by upregulating BMAL1 (a circadian clock component that has been reported to promote peroxisome proliferator activated receptor alpha (PPARα)-mediated fatty β-oxidation by upregulating de novo lipid synthesis). On the other hand, hepatocyte-specific loss of NCoR1 exacerbated alcohol-induced liver inflammation and oxidative stress by recruiting monocyte-derived macrophages via C-C motif chemokine ligand 2 (CCL2). In the mouse hepatocyte line AML12, NCoR1 knockdown significantly increased ethanol-induced CCL2 release. These results suggest that hepatocyte NCoR1 plays distinct roles in controlling liver inflammation and steatosis, which provides new insights into the development of treatments for steatohepatitis induced by chronic alcohol consumption., (© 2022. The Author(s), under exclusive licence to Shanghai Institute of Materia Medica, Chinese Academy of Sciences and Chinese Pharmacological Society.)- Published
- 2022
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4. Effect of vegetation utilization on runoff and sediment production on grain-for-green slopes in the wind-water erosion crisscross region.
- Author
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Wang ZH, Zhang FB, Yang MY, Ren RX, Deng XX, Cao XJ, and Li ZB
- Subjects
- China, Conservation of Natural Resources, Rain, Soil, Environmental Monitoring, Geologic Sediments analysis, Geological Phenomena, Water, Wind
- Abstract
To effectively utilize the vegetation on grain-for-green slopes in the wind-water erosion crisscross region, it is necessary to determine the reasonable vegetation utilization intensity. We set up runoff plots on slopes which were not cultivated and were closed for many years in the Liudaogou catchment, a typical catchment in wind-water erosion crisscross region of the Loess Plateau. With artificial simulated rainfall experiments, the characteristics of runoff and sediment yield on slopes (10°, 20° and 30°) under different utilization intensity of vegetation were studied to select the reasonable utilization intensity. The results showed that the runoff rate in the process of rainfall simulation could be divided into two periods: rapidly increasing in the initial period and slow increasing or quasi-steady state in the middle and late periods. The variation of erosion rate during the rainfall was dependent on the slope. The utilization intensity had a significant effect on the runoff yield, which increased with the increasing utilization intensities. The slope gradient had a significant effect on the sediment yield, with the variation of sediment yield with slope gradient being: 20°>30°>10°. Compared with the unused (natural) plots, the relative runoff and sediment increased with increasing utilization intensities. Predicted based on the rainfall data, annual soil erosion amount on the slope would be basically lower than the tolerance level of soil loss when the vegetation cover on the slope surface reached 25% in 15 years after abandoning reclamation. More attention should be paid to the restoration and management of vegetation on the slope of 20° in this area.
- Published
- 2018
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5. Heat Shock Protein 90 Facilitates Latent HIV Reactivation through Maintaining the Function of Positive Transcriptional Elongation Factor b (p-TEFb) under Proteasome Inhibition.
- Author
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Pan XY, Zhao W, Wang CY, Lin J, Zeng XY, Ren RX, Wang K, Xun TR, Shai Y, and Liu SW
- Subjects
- CD4-Positive T-Lymphocytes virology, Cyclin-Dependent Kinase 9 genetics, DNA-Binding Proteins genetics, DNA-Binding Proteins metabolism, Female, HIV Infections drug therapy, HIV Infections genetics, HIV Infections metabolism, HSP90 Heat-Shock Proteins genetics, Heat Shock Transcription Factors, Humans, Male, Proteasome Endopeptidase Complex genetics, Transcription Elongation, Genetic drug effects, Transcription Factors genetics, Transcription Factors metabolism, Virus Activation physiology, Virus Latency physiology, CD4-Positive T-Lymphocytes metabolism, Cyclin-Dependent Kinase 9 metabolism, HIV-1 physiology, HSP90 Heat-Shock Proteins metabolism, Proteasome Endopeptidase Complex metabolism, Proteasome Inhibitors pharmacology, Virus Activation drug effects, Virus Latency drug effects
- Abstract
The persistence of HIV in resting memory CD4
+ T cells at a latent state is considered as the major barrier on the path to achieve a cure for HIV. Proteasome inhibitors (PIs) were previously reported as latency reversing agents (LRAs) but the mechanism underlying this function is yet unclear. Here we demonstrate that PIs reactivate latent HIV ex vivo without global T cell activation, and may facilitate host innate immune responses. Mechanistically, latent HIV reactivation induced by PIs is mediated by heat shock factor 1 (HSF1) via the recruitment of the heat shock protein (HSP) 90-positive transcriptional elongation factor b (p-TEFb) complex. Specifically, HSP90 downstream HSF1 gives positive feedback to the reactivation process through binding to cyclin-dependent kinase 9 (CDK9) and preventing it from undergoing degradation by the proteasome. Overall, these findings suggest proteasome inhibitors as potential latency reversing agents. In addition, HSF1/HSP90 involved in HIV transcription elongation, may serve as therapeutic targets in HIV eradication., (© 2016 by The American Society for Biochemistry and Molecular Biology, Inc.)- Published
- 2016
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6. No improvement in serological response among serofast latent patients retreated with benzathine penicillin.
- Author
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Ren RX, Wang LN, Zheng HY, and Li J
- Subjects
- Adult, Case-Control Studies, Dose-Response Relationship, Drug, Female, Humans, Male, Penicillin G Benzathine therapeutic use, Retreatment, Retrospective Studies, Syphilis blood, Syphilis diagnosis, Syphilis Serodiagnosis, Syphilis, Latent blood, Time Factors, Treatment Failure, Treatment Outcome, Anti-Bacterial Agents therapeutic use, Penicillin G Benzathine administration & dosage, Syphilis drug therapy, Syphilis, Latent drug therapy
- Abstract
Persistent non-treponemal titres after treatment are common among patients with latent syphilis. Although retreatment is often done in clinical practice, optimal management remains uncertain due to the paucity of data regarding serological response to retreatment and long-term outcomes. We compared the serological responses of serofast latent syphilis patients retreated with 7.2 million units of benzathine penicillin with the responses of patients who did not receive retreatment (control group). We retrospectively analysed the serological response to therapy following retreatment of 35 serofast latent syphilis patients at 12 months with benzathine penicillin 2.4 million units weekly for 3 weeks. In all, 74.3% (26/35) of the cases with latent syphilis who failed to achieve serological cure at 12 months after initial therapy achieved serological cure after retreatment and after an additional 12 months of follow-up. However, statistically similar serological cure rate was observed in 80.0% (28/35) of the control group (p > .05). Our findings illustrate no improvement in serological response among serofast latent patients retreated with three doses of benzathine penicillin., (© The Author(s) 2015.)
- Published
- 2016
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7. Treponema pallidum-specific antibody expression for the diagnosis of different stages of syphilis.
- Author
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Sun R, Lai DH, Ren RX, Lian S, and Zhang HP
- Subjects
- Adolescent, Adult, Aged, Female, Humans, Immunoglobulin G blood, Immunoglobulin M blood, Male, Middle Aged, Antibodies, Bacterial blood, Syphilis diagnosis, Treponema pallidum immunology
- Abstract
Background: Tp15, Tp17, Tp45, and Tp47 are outer-membrane proteins found in Treponema pallidum, the etiologic agent of syphilis. These proteins are potent antigens and are potential markers for the serological detection of syphilis. The present study analyzed antibodies to these protein antigens (TP-IgM and TP-IgG) in human serum and investigated the expression of these antibodies during different stages of syphilis., Methods: Serum samples were collected from 69 subjects (male 45, female 24) diagnosed with syphilis and analyzed by Western blotting for the expression of IgM and IgG against the four protein antigens. Expression levels of the target antibodies were compared during the same stage of syphilis as well as between different stages of this disease., Results: In subjects with primary syphilis, the positive rate of Tp45 IgM was higher than that of other TP-IgM. Tp15 IgM was detected only in subjects with tertiary syphilis. Similarly, the seroprevalence of Tp45 IgG in primary syphilis was higher than for other TP-IgG. No target TP-IgM was detected in subjects with latent syphilis. In subjects with secondary syphilis, the expression level of Tp15 IgG (138.73 ± 20.16) was higher than for other target TP-IgG. In subjects with tertiary syphilis, all target TP-IgG were detected. In subjects with tertiary or latent syphilis, the expression levels of Tp45 IgG (121.33 ± 11.04 and 110.10 ± 40.19, respectively) were higher than those of other target TP-IgG. The expression levels of all Tp-IgM were similar before or after anti-syphilis treatment. In comparison, the expression levels of all TP-IgG decreased compared with the pre-treatment levels, and this decrease was statistically significant (both P < 0.05) for Tp17 IgG and Tp47 IgG., Conclusions: After Treponema pallidum infection, Tp45 IgM appeared first and Tp15 IgM occurred during later stages. The positive rates of all TP-IgG increased with the duration of this disease. Anti-syphilis treatment reduced the expression levels of Tp17 IgG and Tp47 IgG. Larger-scale studies are required to further validate the value of Tp15, Tp17, Tp45, and Tp47 as markers for the early detection of primary and latent syphilis.
- Published
- 2013
8. Effects of acupuncture on the outcomes of in vitro fertilization: a systematic review and meta-analysis.
- Author
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Qu F, Zhou J, and Ren RX
- Subjects
- Abortion, Spontaneous, Embryo Implantation, Female, Humans, Live Birth, Pregnancy, Acupuncture Therapy, Fertilization in Vitro, Pregnancy Outcome
- Abstract
Objectives: The objective of this article was to conduct a systematic review with meta-analysis of the trials of acupuncture during in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) treatment on the outcomes of clinical pregnancy, biochemical pregnancy, ongoing pregnancy, implantation rate, live birth, and miscarriage., Search Strategy: The search was conducted by using MEDLINE(®), SCISEARCH, the Cochrane Menstrual Disorders and Subfertility Group trials register, AMED, Cumulative Index to Nursing and Allied Health Literature, EMBASE, Wanfang Database, China Academic Journal Electronic full text Database in China National Knowledge Infrastructure, Index to Chinese Periodical Literature, ISI Proceedings for conference abstracts, and ISRCTN Register and Meta-register for randomized controlled trials., Data Collection and Analysis: Study selection, quality appraisal, and data extraction were performed independently and in duplicate. The measures of treatment effect were the pooled relative risks (RR) of achieving clinical pregnancy, biochemical pregnancy, ongoing pregnancy, implantation rate, live birth, or miscarriage for women in the acupuncture group compared with women in the control group., Results: Using the random-effects model, pooling of the effect estimates from all of the 17 trials showed no significant difference in the clinical pregnancy outcome between the acupuncture and the control groups (RR=1.09, 95% confidence interval (CI) 0.94-1.26, p=0.25). No significant differences in the biochemical pregnancy, ongoing pregnancy, implantation rate, live birth, or miscarriage outcomes were found between the acupuncture and the control groups (biochemical pregnancy: RR=1.01, 95% CI 0.84-1.20, p=0.95; ongoing pregnancy: RR=1.20, 95% CI 0.93-1.56, p=0.16; implantation rate: RR=1.22, 95% CI 0.93-1.62, p=0.16; live birth: RR=1.42, 95% CI 0.92-2.20, p=0.11; miscarriage outcomes: RR=0.94, 95% CI 0.67-1.33, p=0.74)., Conclusions: No significant benefits of acupuncture are found to improve the outcomes of IVF or ICSI.
- Published
- 2012
- Full Text
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9. A meta-analysis of relationship between birth weight and cord blood leptin levels in newborns.
- Author
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Ren RX and Shen Y
- Subjects
- Humans, Infant, Newborn, Birth Weight, Fetal Blood, Leptin blood
- Abstract
Context: Low cord blood leptin concentration is implicated as a risk factor for small for gestational age (SGA) babies. However, the association of strength, consistency, independence, and confounding factors of this affliction has not been systematically examined., Objective: To determine if there is a difference in cord blood leptin concentration between SGA and appropriate for gestational age (AGA) newborns, and to observe whether the sample origins, GA, pregnancy-induced hypertension (PIH) and congenital malformation (CM) are confounding factors of the meta-analysis., Data Sources and Study Selection: Relevant studies published between 1996 and 2007 were identified through literature searches using Ovid, Medline, PubMed, Web of Science, National Knowledge Infrastructure, Wanfang Data, and VIP China Scientific Journal Database, based on the following key words: leptin, intrauterine growth restriction, intrauterine growth retardation, fetal growth restriction, and small for gestational age., Data Extraction: A meta-analysis was conducted to analyze the difference of the cord blood leptin concentrations between SGA and AGA newborns. Then the stratified meta-analyses were repeated with a multivariate model to adjust for potential confounders, i.e., samples origin (Chinese newborns vs. non-Chinese newborns), GA (the term-newborns vs. the mixed GA newborns), PIH or CM (the newborns excluding PIH or CM vs. the newborns not excluding PIH or CM)., Data Synthesis: Twenty articles including 514 SGA newborns and 1006 AGA newborns were collected. The cord leptin concentrations of SGA newborns were lower than those of AGA newborns [WMD (95%CI), -4.42 (-5.54, -3.29) ng/ml; P<0.01; n=1520 newborns]. The results of stratified meta-analyses showed similar results in Chinese vs. non-Chinese newborns and term vs. mixed GA newborns, respectively. However, the newborns not excluding PIH or CM had a wider 95%CI than the newborns excluding PIH or CM [WMD (95%CI), -4.17 (-5.00, -3.33) ng/ml vs. -4.47 (-9.61, 0.67) ng/ml)], and there was no significant difference in cord blood leptin concentrations between SGA and AGA newborns in the newborns not excluding PIH or CM (P=0.09)., Conclusions: SGA babies have low cord leptin concentrations. Other factors that may influence cord leptin levels are maternal PIH and CM.
- Published
- 2010
- Full Text
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10. [Pollutant components and microbial community structure of oil-polluted soils after converted from paddy field to upland].
- Author
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Ren RX, Zhang Y, Li H, Wang R, Xu H, and Chen GX
- Subjects
- China, Fatty Acids analysis, Phospholipids analysis, Soil analysis, Gasoline, Polycyclic Aromatic Hydrocarbons analysis, Soil Microbiology, Soil Pollutants analysis
- Abstract
With the oil-polluted soils after converted from paddy field to upland field for different years in the Shenfu wastewater irrigation area of Shenyang as test materials, the concentrations of their oil pollutants were determined, and the microbial community structure was investigated by denaturing gradient gel electrophoresis (DGGE) and phospholipids fatty acid (PLFA) methods. The results showed that the proportions of total polynuclear aromatic hydrocarbons (PAHs) in total petroleum hydrocarbons (TPHs) and of high molecular weight PAHs in total PAHs increased with the increasing years of field conversion. Total phospholipid fatty acids (PLFAs) had a significant positive correlation with total TPHs, but no correlation with total PAHs. Both DGGE and PLFA analyses indicated that the community structure of soil microbes was mainly correlated with geographical location, and changed obviously when the concentrations of oil pollutants in soil increased to a definite level.
- Published
- 2007
11. Ionic liquid high-temperature gas sensor array.
- Author
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Jin X, Yu L, Garcia D, Ren RX, and Zeng X
- Subjects
- Ions, Spectroscopy, Fourier Transform Infrared, Thermodynamics, Hot Temperature
- Abstract
A novel sensor array using seven room-temperature ionic liquids (ILs) as sensing materials and a quartz crystal microbalance (QCM) as a transducer was developed for the detection of organic vapors at ambient and elevated temperatures. Ethanol, dichloromethane, benzene, and heptane were selected as representative gas analytes for various kinds of environmental pollutants and common industrial solvents. The QCM/IL sensors responded proportionately and reversibly to the organic vapor concentrations (i.e., ethanol, heptane, and benzene) in the gas phase from 0 to 100% saturation at room and elevated temperatures (e.g., 120 degrees C) but deviated from this linear relationship at high concentrations for dichloromethane, a highly volatile compound. Linear discriminant analysis was used to analyze the sensing patterns. Excellent classifications were obtained for both known and unknown concentrations of vapor samples. The correct classifications were 100% for known concentration samples and 96% for samples with unknown concentrations. Thermodynamics and ATR-FT-IR studies were conducted to understand specific molecular interactions, the strength of the interaction between ILs and organic vapors, and the degree of ordering that takes place upon dissolution of the vapors in ILs. The different response intensity of the QCM/IL sensors to the organic vapors depends on the different solubilities of organic vapors in ILs and varying molecular/ion interactions between each organic vapor and IL. The diverse set of IL studied showed selective responses due to structural differences. Therefore, a sensor array of ILs would be able to effectively differentiate different vapors in pattern recognitions, facilitating discrimination by their distinctive patterns in response to organic vapors in both room and high temperatures.
- Published
- 2006
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12. Photochemistry of A1E, a retinoid with a conjugated pyridinium moiety: competition between pericyclic photooxygenation and pericyclization.
- Author
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Jockusch S, Ren RX, Jang YP, Itagaki Y, Vollmer-Snarr HR, Sparrow JR, Nakanishi K, and Turro NJ
- Subjects
- Cyclization, Nuclear Magnetic Resonance, Biomolecular, Oxidation-Reduction, Photochemistry, Photolysis, Spectrum Analysis, Pyridinium Compounds chemistry, Retinoids chemistry
- Abstract
The photochemistry of the retinoid analogue A1E shows an oxygen and solvent dependence. Irradiation of A1E with visible light (lambda(irr) = 425 nm) in methanol solutions resulted in pericyclization to form pyridinium terpenoids. Although the quantum yield for this cyclization is low (approximately 10(-4)), nevertheless the photochemical transformation occurs with quantitative chemical yield with remarkable chemoselectivity and diastereoselectivity. Conversely, irradiation of A1E under the same irradiation conditions in air-saturated carbon tetrachloride or deuterated chloroform produced a cyclic 5,8-peroxide as the major product. Deuterium solvent effects, experiments utilizing endoperoxide, phosphorescence, and chemiluminescence quenching studies strongly support the involvement of singlet oxygen in the endoperoxide formation. It is proposed that, upon irradiation, in the presence of oxygen, A1E acts as a sensitizer for generation of singlet oxygen from triplet oxygen present in the solution; the singlet oxygen produced reacts with A1E to produce cyclic peroxide. Thus, the photochemistry of A1E is characterized by two competing reactions, cyclization and peroxide formation. The dominant reaction is determined by the concentration of oxygen, the concentration of A1E, and the lifetime of singlet oxygen in the solvent employed. If the lifetime of singlet oxygen in a given solvent is long enough, then oxidation (peroxide formation) is the major reaction. If the singlet oxygen produced is quenched by the protonated solvent molecules faster than singlet oxygen reacts with A1E, then cyclization dominates.
- Published
- 2004
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13. Studies in the Total Synthesis of Heliquinomycinone: Proof of Concept and Assembly of a Fully Mature Spirocyclization Precursor This work was supported by the National Institutes of Health (Grant numbers: AI 16943 and HL25848). A Postdoctoral Fellowship is gratefully acknowledged by R.X.R. (NIH, Grant Number IF32EY06750-0181). The authors thank Dr. Daniel Chen for important initial experiments, Dr. Brian Bridgewater and Prof. Ged Parkin of Columbia University for X-ray crystal structure analysis of 11 a, and Yashuiro Itagaki for high-resolution mass spectral analyses.
- Author
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Qin D, Ren RX, Siu T, Zheng C, and Danishefsky SJ
- Published
- 2001
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14. Mild conversion of alcohols to alkyl halides using halide-based ionic liquids at room temperature.
- Author
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Ren RX and Wu JX
- Abstract
[reaction--see text] Alcohols were efficiently converted to alkyl halides using 1-n-butyl-3-methylylimidazolium halides (ionic liquids) in the presence of Brønsted acids at room temperature. The alkyl halide products were easily isolated from the reaction mixture via simple decantation or extraction, and the 1-n-butyl-3-methylimidazolium cation could be recycled for further uses.
- Published
- 2001
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15. Factors Contributing to Aromatic Stacking in Water: Evaluation in the Context of DNA.
- Author
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Guckian KM, Schweitzer BA, Ren RX, Sheils CJ, Tahmassebi DC, and Kool ET
- Abstract
We report the use of thermodynamic measurements in a self-complementary DNA duplex (5'-dXCGCGCG)(2), where X is an unpaired natural or nonnatural deoxynucleoside, to study the forces that stabilize aqueous aromatic stacking in the context of DNA. Thermal denaturation experiments show that the core duplex (lacking X) is formed with a free energy (37 °C) of -8.1 kcal·mol(-1) in a pH 7.0 buffer containing 1 M Na(+). We studied the effects of adding single dangling nucleosides (X) where the aromatic "base" is adenine, guanine, thymine, cytosine, pyrrole, benzene, 4-methylindole, 5-nitroindole, trimethylbenzene, difluorotoluene, naphthalene, phenanthrene, and pyrene. Adding these dangling residues is found to stabilize the duplex by an additional -0.8 to -3.4 kcal·mol(-1). At 5 μM DNA concentration, T(m) values range from 41.7 °C (core sequence) to 64.1 °C (with dangling pyrene residues). For the four natural bases, the order of stacking ability is A > G ≥ T = C. The nonpolar analogues stack more strongly in general than the more polar natural bases. The stacking geometry was confirmed in two cases (X = adenine and pyrene) by 2-D NOESY experiments. Also studied is the effect of ethanol cosolvent on the stacking of natural bases and pyrene. Stacking abilities were compared to calculated values for hydrophobicity, dipole moment, polarizability, and surface area. In general, hydrophobic effects are found to be larger than other effects stabilizing stacking (electrostatic effects, dispersion forces); however, the natural DNA bases are found to be less dependent on hydrophobic effects than are the more nonpolar compounds. The results also point out strategies for the design nucleoside analogues that stack considerably more strongly than the natural bases; such compounds may be useful in stabilizing designed DNA structures and complexes.
- Published
- 2000
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16. A thymidine triphosphate shape analog lacking Watson-Crick pairing ability is replicated with high sequence selectivity.
- Author
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Moran S, Ren RX, and Kool ET
- Subjects
- Base Composition, DNA Polymerase I metabolism, Hydrogen Bonding, Kinetics, Nucleic Acid Denaturation, Substrate Specificity, Thymine Nucleotides metabolism, Nucleic Acid Conformation, Thymine Nucleotides chemistry
- Abstract
Compound 1 (F), a nonpolar nucleoside analog that is isosteric with thymidine, has been proposed as a probe for the importance of hydrogen bonds in biological systems. Consistent with its lack of strong H-bond donors or acceptors, F is shown here by thermal denaturation studies to pair very poorly and with no significant selectivity among natural bases in DNA oligonucleotides. We report the synthesis of the 5'-triphosphate derivative of 1 and the study of its ability to be inserted into replicating DNA strands by the Klenow fragment (KF, exo- mutant) of Escherichia coli DNA polymerase I. We find that this nucleotide derivative (dFTP) is a surprisingly good substrate for KF; steady-state measurements indicate it is inserted into a template opposite adenine with efficiency (Vmax/Km) only 40-fold lower than dTTP. Moreover, it is inserted opposite A (relative to C, G, or T) with selectivity nearly as high as that observed for dTTP. Elongation of the strand past F in an F-A pair is associated with a brief pause, whereas that beyond A in the inverted A-F pair is not. Combined with data from studies with F in the template strand, the results show that KF can efficiently replicate a base pair (A-F/F-A) that is inherently very unstable, and the replication occurs with very high fidelity despite a lack of inherent base-pairing selectivity. The results suggest that hydrogen bonds may be less important in the fidelity of replication than commonly believed and that nucleotide/template shape complementarity may play a more important role than previously believed.
- Published
- 1997
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17. C-Nucleosides Derived from Simple Aromatic Hydrocarbons.
- Author
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Chaudhuri NC, Ren RX, and Kool ET
- Abstract
We describe the synthesis, structure and DNA incorporation of a class of novel aromatic C-deoxynucleosides in which benzenes and larger polycyclic aromatics serve as DNA base analogs. Novel approaches have been developed for glycosidic bond formation and for epimenzation of the anomeric substitutents to β-configuration, and we describe some of the properties of such compounds in DNA.
- Published
- 1997
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18. Difluorotoluene, a Nonpolar Isostere for Thymine, Codes Specifically and Efficiently for Adenine in DNA Replication.
- Author
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Moran S, Ren RX, Rumney S, and Kool ET
- Published
- 1997
- Full Text
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19. Experimental Measurement of Aromatic Stacking Affinities in the Context of Duplex DNA.
- Author
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Guckian KM, Schweitzer BA, Ren RX, Sheils CJ, Paris PL, Tahmassebi DC, and Kool ET
- Published
- 1996
- Full Text
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20. Naphthalene, Phenanthrene, and Pyrene as DNA Base Analogues: Synthesis, Structure, and Fluorescence in DNA.
- Author
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Ren RX, Chaudhuri NC, Paris PL, Rumney S, and Kool ET
- Abstract
We describe the synthesis, structures, and DNA incorporation of deoxyribonucleosides carrying polycyclic aromatic hydrocarbons as the DNA "base" analogue. The new polycyclic compounds are 1-naphthyl, 2-naphthyl, 9-phenanthrenyl, and 1-pyrenyl deoxynucleosides. The compounds are synthesized using a recently developed C-glycosidic bond formation method involving organocadmium derivatives of the aromatic compounds coupling with a 1α-chlorodeoxyribose precursor. The principal products of this coupling are the α-anomers of the deoxyribosides. An efficient method has also been developed for epimerization of the α-anomers to β-anomers by acid-catalyzed equilibration; this isomerization is successfully carried out on the four polycyclic nucleosides as well as two substituted phenyl nucleosides. The geometry of the anomeric substitution is derived from (1)H NOE experiments and is also correlated with a single-crystal X-ray structure of one α-isomer. Three of the polycyclic C-nucleoside derivatives are incorporated into DNA oligonucleotides via their phosphoramidite derivatives; the pyrenyl and phenanthrenyl derivatives are shown to be fluorescent in a DNA sequence. The results (1) broaden the scope of our C-glycoside coupling reaction, (2) demonstrate that (using a new acid-catalyzed epimerization) both α- and β-anomers are easily synthesized, and (3) constitute a new class of deoxynucleoside derivatives. Such nucleoside analogues may be useful as biophysical probes for the study of noncovalent interactions such as aromatic π-stacking in DNA. In addition, the fluorescence of the phenanthrene and pyrene nucleosides may make them especially useful as structural probes.
- Published
- 1996
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21. Non-hydrogen bonding 'terminator' nucleosides increase the 3'-end homogeneity of enzymatic RNA and DNA synthesis.
- Author
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Moran S, Ren RX, Sheils CJ, Rumney S 4th, and Kool ET
- Subjects
- Base Sequence, DNA chemistry, Deoxyribose chemical synthesis, Deoxyribose pharmacology, Escherichia coli enzymology, Indoles chemical synthesis, Molecular Sequence Data, Naphthalenes chemical synthesis, Nucleosides chemical synthesis, Nucleosides chemistry, Pyrenes chemical synthesis, RNA chemistry, Templates, Genetic, Viral Proteins, DNA biosynthesis, DNA Polymerase I metabolism, DNA-Directed RNA Polymerases metabolism, Deoxyribose analogs & derivatives, Hydrogen Bonding, Indoles pharmacology, Naphthalenes pharmacology, Nucleosides pharmacology, Pyrenes pharmacology, RNA biosynthesis
- Abstract
We report the use of novel non-polar nucleoside analogues as terminators of enzymatic RNA and DNA synthesis. Standard 'runoff' RNA synthesis by T7 RNA polymerase gives RNA products which have ragged ends as a result of transcription which often extends beyond the end of the template DNA strand. Similarly, the Klenow fragment of Escherichia coli DNA polymerase I tends to run past the end of the template strand during DNA synthesis. We report here that certain non-hydrogen-bonding nucleoside analogues, when placed at the downstream 5'-end of a template DNA strand, cause the polymerases to stop more abruptly at the last coding nucleotide. This results in a considerably more homogeneous oligonucleotide being produced. Three novel nucleosides are tested as potential terminators: 4-methylindole beta-deoxynucleoside (M), 1-naphthyl alpha-deoxynucleoside (N) and 1-pyrenyl alpha-deoxynucleoside (P). Comparison is made to an abasic nucleoside (phi) and to unterminated synthesis. Of these, M is found to be the most efficient at terminating transcription, and both P and M are highly effective at terminating DNA synthesis. It is also found that the ability of a nucleoside to stall synthesis when it is internally placed in the template strand is not necessarily a good predictor of terminating ability at the end of a template. Such terminator nucleosides may be useful in the preparative enzymatic synthesis of RNA and DNA, rendering purification simpler and lowering the cost of synthesis by preventing the uptake of potentially costly nucleotides into unwanted products.
- Published
- 1996
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22. Effects of rhynchophylline on motor activity of mice and serotonin and dopamine in rat brain.
- Author
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Shi JS, Huang B, Wu Q, Ren RX, and Xie XL
- Subjects
- Animals, Brain Chemistry drug effects, Drugs, Chinese Herbal pharmacology, Female, In Vitro Techniques, Indole Alkaloids, Male, Mice, Mice, Inbred BALB C, Oxindoles, Rats, Rats, Wistar, Alkaloids pharmacology, Brain metabolism, Dopamine metabolism, Hypnotics and Sedatives pharmacology, Motor Activity drug effects, Serotonin metabolism
- Abstract
Rhynchophylline (Rhy) reduced the spontaneous motor activity and enhanced the sedative and hypnotic effects of sodium pentobarbital in mice. The effects of Rhy on serotonin (5-HT) and dopamine (DA) concentrations in rat brain, and the release of 5-HT and DA from the regional brain slices were studied by a fluorescence detector. Rhy increased the 5-HT content in the hypothalamus and cortex, but reduced the DA concentrations in the cortex, amygdala, and spinal cord. Rhy promoted the release of endogenous DA from 4 brain regions. The release of 5-HT was increased in 2 brain regions and decreased in hypothalamus slice. However, Rhy inhibited the release of both 5-HT and DA evoked by high potassium.
- Published
- 1993
23. [Subselective embolization of the intra or extra-cranial polyvascular lesions].
- Author
-
Wu RQ, Wan DJ, and Ren RX
- Subjects
- Adult, Ependymoma therapy, Female, Gelatin Sponge, Absorbable, Humans, Male, Middle Aged, Brain Neoplasms therapy, Embolization, Therapeutic adverse effects, Hemangioma, Cavernous therapy, Meningeal Neoplasms therapy, Meningioma therapy
- Published
- 1985
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