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Zhou Y, Xu JC, Jia YF, Xu CS. Role of death receptors in the regulation of hepatocyte proliferation and apoptosis during rat liver regeneration. GENETICS AND MOLECULAR RESEARCH 2015; 14:14066-75. [PMID: 26535721 DOI: 10.4238/2015.october.29.26] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The balance between hepatocyte proliferation and apoptosis is critical for liver homeostasis during liver regeneration. We created a rat liver regeneration model by partial hepatectomy (PH) to investigate the overall mechanism that regulates the proliferation and apoptosis of hepatocytes. The Rat Genome 230 2.0 Array was used to investigate changes in the expression levels of genes associated with the known proliferation or apoptosis signaling pathways. Ingenuity Pathway Analysis 9.0 was used to determine interactions among these signaling pathways. The results revealed that the expression levels of multiple key genes in three death receptor (DR) pathways, Fas/FasL, TNFR/TNFα, and DR6, were significantly altered in hepatocytes after PH. The expression level of the gene encoding DR6 increased by over 100-fold, whereas the levels of the genes encoding Fas, FasL, and TNFα were increased by 2-4-fold 12 h after PH. Fas/FasL, TNFR/TNFα, and DR6 are known to participate in numerous cellular events including cell proliferation and apoptosis. Our results suggest that the DR6 pathway plays a major role in the regulation of hepatocyte apoptosis, whereas Fas/FasL and TNFR/TNFα pathways may have roles in coordinating signaling activities between proliferation and apoptosis.
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Gao X, Huang SS, Yuan YY, Wang GJ, Xu JC, Ji YB, Han MY, Yu F, Kang DY, Lin X, Dai P. Targeted gene capture and massively parallel sequencing identify TMC1 as the causative gene in a six-generation Chinese family with autosomal dominant hearing loss. Am J Med Genet A 2015; 167A:2357-65. [PMID: 26079994 DOI: 10.1002/ajmg.a.37206] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Accepted: 05/25/2015] [Indexed: 12/26/2022]
Abstract
Hereditary nonsyndromic hearing loss is extremely heterogeneous. Mutations in the transmembrane channel-like gene1 (TMC1) are known to cause autosomal dominant and recessive forms of nonsyndromic hearing loss linked to the loci of DFNA36 and DFNB7/11, respectively. We characterized a six-generation Chinese family (5315) with progressive, postlingual autosomal dominant nonsyndromic hearing loss (ADNSHL). By combining targeted capture of 82 known deafness genes, next-generation sequencing and bioinformatic analysis, we identified TMC1 c.1714G>A (p. D572N) as the disease-causing mutation. This mutation co-segregated with hearing loss in other family members and was not detected in 308 normal controls. In order to determine the prevalence of TMC1 c.1714G>A in Chinese ADNSHL families, we used DNA samples from 67 ADNSHL families with sloping audiogram and identified two families carry this mutation. To determine whether it arose from a common ancestor, we analyzed nine STR markers. Our results indicated that TMC1 c.1714G>A (p.D572N) account for about 4.4% (3/68) of ADNSHL in the Chinese population.
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Gao X, Su Y, Chen YL, Han MY, Yuan YY, Xu JC, Xin F, Zhang MG, Huang SS, Wang GJ, Kang DY, Guan LP, Zhang JG, Dai P. Identification of Two Novel Compound Heterozygous PTPRQ Mutations Associated with Autosomal Recessive Hearing Loss in a Chinese Family. PLoS One 2015; 10:e0124757. [PMID: 25919374 PMCID: PMC4412678 DOI: 10.1371/journal.pone.0124757] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Accepted: 03/05/2015] [Indexed: 11/25/2022] Open
Abstract
Mutations in PTPRQ are associated with deafness in humans due to defects of stereocilia in hair cells. Using whole exome sequencing, we identified responsible gene of family 1572 with autosomal recessively non-syndromic hearing loss (ARNSHL). We also used DNA from 74 familial patients with ARNSHL and 656 ethnically matched control chromosomes to perform extended variant analysis. We identified two novel compound heterozygous missense mutations, c. 3125 A>G p.D1042G (maternal allele) and c.5981 A>G p.E1994G (paternal allele), in the PTPRQ gene, as the cause of recessively inherited sensorineural hearing loss in family 1572. Both variants co-segregated with hearing loss phenotype in family 1572, but were absent in 74 familial patients. Heterozygosity for c. 3125 A>G was identified in two samples from unaffected Chinese individuals (656 chromosomes). Therefore, the hearing loss in this family was caused by two novel compound heterozygous mutations in PTPRQ.
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Hu MD, Wang GS, Xu J, Yao W, He BF, Yang Y, Mao M, Wang Q, Xu JC. Separation, purification, and identification of flagellin, and preparation of its antisera. GENETICS AND MOLECULAR RESEARCH 2014; 13:9161-70. [PMID: 25501138 DOI: 10.4238/2014.november.7.3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The aim of this study was to separate, purify, and identify Salmonella paratyphi A flagellin, and to prepare its antisera. Primary flagellin was isolated from S. paratyphi A using the acid lysis method. The flagellin was purified with weak anion exchange chromatography and the protein was identified with sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), Western blot, and negative staining with phosphotungstic acid with scanning electron microscopy (SEM). The production of the obtained flagellin was then quantified. New Zealand white rabbits were then immunized with the isolated flagellin, the presence of serum anti-flagellin antibodies was assessed with the immunoblot test, and its potency was determined with the double immunodiffusion test. The results of SDS-PAGE showed that the molecular weight (m.w.) of the purified flagellin was 52 x 10(3). The immunoblot test also showed a band at 52 x 10(3) m.w. The SEM results showed that the flagellin was filamentous. These three results showed that the protein was homogeneous. The protein quantification analysis found that 4.8 ± 0.5 mg flagellin could be extracted per 1 g wet weight bacteria. The titer of the anti-flagellin antiserum was 1:64. Through this method, we obtained high productions of flagellin, which could be easily purified, identified, and prepared into high titer antiserum.
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Gao X, Wang GJ, Yuan YY, Xin F, Han MY, Lu JQ, Zhao H, Yu F, Xu JC, Zhang MG, Dong J, Lin X, Dai P. Novel compound heterozygous mutations in MYO7A Associated with Usher syndrome 1 in a Chinese family. PLoS One 2014; 9:e103415. [PMID: 25080338 PMCID: PMC4117490 DOI: 10.1371/journal.pone.0103415] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Accepted: 06/28/2014] [Indexed: 11/19/2022] Open
Abstract
Usher syndrome is an autosomal recessive disease characterized by sensorineural hearing loss, age-dependent retinitis pigmentosa (RP), and occasionally vestibular dysfunction. The most severe form is Usher syndrome type 1 (USH1). Mutations in the MYO7A gene are responsible for USH1 and account for 29–55% of USH1 cases. Here, we characterized a Chinese family (no. 7162) with USH1. Combining the targeted capture of 131 known deafness genes, next-generation sequencing, and bioinformatic analysis, we identified two deleterious compound heterozygous mutations in the MYO7A gene: a reported missense mutation c.73G>A (p.G25R) and a novel nonsense mutation c.462C>A (p.C154X). The two compound variants are absent in 219 ethnicity-matched controls, co-segregates with the USH clinical phenotypes, including hearing loss, vestibular dysfunction, and age-dependent penetrance of progressive RP, in family 7162. Therefore, we concluded that the USH1 in this family was caused by compound heterozygous mutations in MYO7A.
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Biaggi-Labiosa A, Solá F, Lebrón-Colón M, Evans LJ, Xu JC, Hunter G, Berger GM, González JM. A novel methane sensor based on porous SnO2 nanorods: room temperature to high temperature detection. NANOTECHNOLOGY 2012; 23:455501. [PMID: 23064120 DOI: 10.1088/0957-4484/23/45/455501] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
We report for the first time a novel room temperature methane (CH(4)) sensor fabricated using porous tin oxide (SnO(2)) nanorods as the sensing material. The porous SnO(2) nanorods were synthesized by using multiwall carbon nanotubes (MWCNTs) as templates. Current versus time curves were obtained demonstrating the room temperature sensing capabilities of the sensor system when exposed to 0.25% CH(4) in air. The sensor also exhibited a wide temperature range for different concentrations of CH(4) (25-500 °C), making it useful in harsh environments as well.
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Xu JC, Huang DL, Hou ZH, Guo WW, Sun JH, Zhao LD, Yu N, Young WY, He DZZ, Yang SM. Type I hair cell regeneration induced by Math1 gene transfer following neomycin ototoxicity in rat vestibular sensory epithelium. Acta Otolaryngol 2012; 132:819-28. [PMID: 22668196 DOI: 10.3109/00016489.2012.673233] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
CONCLUSION In the current study, hair cells of vestibular terminal organs in rats were completely eliminated with trans-scala vestibuli injection of neomycin, and then the Math1 gene was transferred. It was shown that type I vestibular hair cells were regenerated and synapses were formed. OBJECTIVES The objective of this study was to identify the cell type of the regenerated vestibular hair cells and relative innervation and synaptic linkage after hair cells of vestibular terminal organs in rats were completely eliminated. METHODS Neomycin injection was used to eliminate all the vestibular terminal organs, and then the animals were treated with an injection of Ad-Math1-EGFP in the scala vestibuli of the cochlea. RESULTS Math1 gene transfer into the inner ear induced type I hair cell regeneration and synaptic formation. However, neither the number nor the appearance of the hair cells was normal.
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Hunter GW, Xu JC, Biaggi-Labiosa AM, Laskowski D, Dutta PK, Mondal SP, Ward BJ, Makel DB, Liu CC, Chang CW, Dweik RA. Smart sensor systems for human health breath monitoring applications. J Breath Res 2011; 5:037111. [PMID: 21896970 DOI: 10.1088/1752-7155/5/3/037111] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Breath analysis techniques offer a potential revolution in health care diagnostics, especially if these techniques can be brought into standard use in the clinic and at home. The advent of microsensors combined with smart sensor system technology enables a new generation of sensor systems with significantly enhanced capabilities and minimal size, weight and power consumption. This paper discusses the microsensor/smart sensor system approach and provides a summary of efforts to migrate this technology into human health breath monitoring applications. First, the basic capability of this approach to measure exhaled breath associated with exercise physiology is demonstrated. Building from this foundation, the development of a system for a portable asthma home health care system is described. A solid-state nitric oxide (NO) sensor for asthma monitoring has been identified, and efforts are underway to miniaturize this NO sensor technology and integrate it into a smart sensor system. It is concluded that base platform microsensor technology combined with smart sensor systems can address the needs of a range of breath monitoring applications and enable new capabilities for healthcare.
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Ji LL, Shen BF, Li DX, Wang D, Leng YX, Zhang XM, Wen M, Wang WP, Xu JC, Yu YH. Relativistic single-cycled short-wavelength laser pulse compressed from a chirped pulse induced by laser-foil interaction. PHYSICAL REVIEW LETTERS 2010; 105:025001. [PMID: 20867711 DOI: 10.1103/physrevlett.105.025001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2010] [Indexed: 05/29/2023]
Abstract
By particle-in-cell simulation and analysis, we propose a plasma approach to generate a relativistic chirped pulse based on a laser-foil interaction. When two counterpropagating circularly polarized pulses interact with an overdense foil, the driving pulse (with a larger laser field amplitude) will accelerate the whole foil to form a double-layer structure, and the scattered pulse (with a smaller laser field amplitude) is reflected by this flying layer. Because of the Doppler effect and the varying velocity of the layer, the reflected pulse is up-shifted for frequency and chirped; thus, it could be compressed to a nearly single-cycled relativistic laser pulse with a short wavelength. Simulations show that a nearly single-cycled subfemtosecond relativistic pulse can be generated with a wavelength of 0.2 μm after dispersion compensation.
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Ji LL, Shen BF, Zhang XM, Wang FC, Jin ZY, Xia CQ, Wen M, Wang WP, Xu JC, Yu MY. Generating quasi-single-cycle relativistic laser pulses by laser-foil interaction. PHYSICAL REVIEW LETTERS 2009; 103:215005. [PMID: 20366047 DOI: 10.1103/physrevlett.103.215005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2009] [Indexed: 05/29/2023]
Abstract
A scheme for producing nearly single-cycle relativistic laser pulses is proposed. When a laser pulse interacts with an overdense thin foil, because of self-consistent nonlinear modulation, the latter will be more transparent to the more intense part of the laser, so that a transmitted pulse can be much shorter than the incident pulse. Using two-dimensional particle-in-cell simulation and analytical modeling, it is found that a transmitted pulse of duration 4 fs and peak intensity 3 x 10{20} W/cm{2} can be generated from a circularly polarized laser pulse. The intensity of the resulting pulse is only limited by that of the incident pulse, since this scheme involves only laser-plasma interaction.
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Jiang Z, Wu CL, Woda BA, Iczkowski KA, Chu PG, Tretiakova MS, Young RH, Weiss LM, Blute RD, Brendler CB, Krausz T, Xu JC, Rock KL, Amin MB, Yang XJ. Alpha-methylacyl-CoA racemase: a multi-institutional study of a new prostate cancer marker. Histopathology 2004; 45:218-25. [PMID: 15330799 DOI: 10.1111/j.1365-2559.2004.01930.x] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIM To test whether alpha-methylacyl-CoA racemase (AMACR) is a sensitive and specific marker of prostate cancer. METHODS AND RESULTS The expression levels of AMACR mRNA were measured by real-time polymerase chain reaction. A total of 807 prostatic specimens were further examined by immunohistochemistry specific for AMACR. Quantitative immunostaining analyses were carried out by using the ChromaVision Automated Cellular Imaging System and the Ariol SL-50 Imaging System, respectively. AMACR mRNA levels measured in prostatic adenocarcinoma were 55 times higher than those in benign prostate tissue. Of 454 cases of prostatic adenocarcinoma, 441 were positive for AMACR, while 254 of 277 cases of benign prostate were negative for AMACR. The sensitivity and specificity of AMACR immunodetection of prostatic adenocarcinomas were 97% and 92%, respectively. Both positive and negative predictive values were 95%. By automatic imaging analyses, the AMACR immunostaining intensity and percentage in prostatic adenocarcinomas were also significantly higher than those in benign prostatic tissue (105.9 versus 16.1 for intensity, 45.7% versus 0.02% and 35.03% versus 4.64% for percentage, respectively). CONCLUSIONS We have demonstrated the promising features of AMACR as a biomarker for prostate cancer in this large series and the potential to develop automated quantitative diagnostic tests.
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Xu JC, Stucki JW, Wu J, Kostka JE, Sims GK. Fate of atrazine and alachlor in redox-treated ferruginous smectite. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2001; 20:2717-2724. [PMID: 11764154 DOI: 10.1897/1551-5028(2001)020<2717:foaaai>2.0.co;2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The oxidation state of structural iron (Fe) in clay minerals exerts a large influence on clay surface chemistry and may affect the adsorption and degradation of pesticides in the environment. This effect, however, has been little investigated. In the present study, herbicides atrazine and alachlor were reacted with ferruginous smectite (sample SWa-1) in its oxidized, reduced (either chemically or bacterially), and reduced-reoxidized states. In some experiments the herbicide was labeled with 14C. Gas chromatography/mass spectrometry (GC-MS) was also used to detect alachlor degradation products. Compared to oxidized clays, reduction by both chemical and microbial treatments decreased the concentration of both herbicides in the surrounding solution. Reoxidized clay exhibited behavior similar to the oxidized clay. Hydrolysis-dechlorination of atrazine occurred in the presence of chemically reduced SWa-1, and GC-MS analysis of alachlor revealed at least 14 degradation products after treatment with reduced clay and only two with the oxidized clay. Interaction of atrazine and alachlor with the clay may be through a H bond with the waters of hydration surrounding interlayer cations, the extent of which should increase with increasing acidity; but under reduced conditions, the validity of this model is unclear. Reduction of structural Fe may affect pH-dependent phenomena in two ways: The increased surface charge density increases the number of hydrated interlayer cations, thereby enhancing surface acidity, and increased electron density at basal surface oxygens increases their Brønsted basicity. Atrazine could, therefore, adsorb and/or degrade through either acid or alkaline hydrolysis pathways. Increased reduction potential of the reduced clay surfaces may also promote degradation.
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Xu JC, Weerasuriya YM, Bennetzen JL. [Construction of genetic map in sorghum and fine mapping of the germination stimulant production gene response to Striga asiatica]. YI CHUAN XUE BAO = ACTA GENETICA SINICA 2001; 28:870-6. [PMID: 11582748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
Sorghum is the fifth important crop in the world. It is also the major food resource in African countries. Striga asiatica is a parasitism weed on sorghum and some other important crops. In this report, two sorghum lines with the difference in response to Striga asiatica, SRN39 (lower Germination Stimulant-GermStim production) and Shanguihong (high GermStim production), were selected as the parents for the construction of a recombinant inbred (RI) population. Ninety-four RI lines were collected for the molecular analysis and GermStim production evaluation. A genetic map was constructed with 251 molecular markers that distributed on 10 different linkage groups. The map covers sorghum genome of 1,779 cm with an average map distance of 7.1 cm between linked markers. It is one of the complete sorghum molecular map in the world. Co-segregation analysis indicated that the germination stimulant gene (GermStim) was located on linkage group J, which was at a distance of 13 cm from the closed marker. Further RAPD analysis between two parents and two DNA pools different in the amount of germination stimulant production, several polymorphic DNA fragments were identified and cloned. Mapping results showed two of them flanked with the GermStim gene at a distance of 1.6 cm and 2.1 cm respectively.
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Li P, Xu JC. The development of highly efficient onium-type peptide coupling reagents based upon rational molecular design. THE JOURNAL OF PEPTIDE RESEARCH : OFFICIAL JOURNAL OF THE AMERICAN PEPTIDE SOCIETY 2001; 58:129-39. [PMID: 11532072 DOI: 10.1034/j.1399-3011.2001.00867.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Novel and highly efficient immonium-, pyridinium- and thiazolium-type peptide coupling reagents, such as BOMI, BDMP, BPMP, BEP, FEP, BEPH, FEPH and BEMT, were developed by rational modifying of the molecular structures of commonly used uronium-type reagents. The high efficiency of these onium salts has been evaluated and proven by model reaction tests and the successful synthesis of various oligopeptides and biologically active peptides, both in solution and in the solid-phase, for example Leu-enkephalin, the pentapeptide moiety of Dolastatin 15 and the immunosuppressive undecapeptide cyclosporin O. Based upon these results, the relationship between the molecular structure and the capability of onium-type peptide coupling reagents was studied. A preliminary guideline for the molecular design of onium-type coupling reagents was developed.
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Xu JC, Li JZ, Zheng XW, Zou LX, Zhu LH. [QTL mapping of the root traits in rice seedling]. YI CHUAN XUE BAO = ACTA GENETICA SINICA 2001; 28:433-8. [PMID: 11441656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Abstract
Drought resistance is one of the most important traits in rice abiotic study. The report here analyzed several major root traits affecting drought resistance expression with the double haploid population (DH) from ZYQ8 (indica)/JX17 (japonica) containing 127 lines. After 10 days solution culturing, three rice root traits, Maximum Root Length (MRL), Dry Root Weight (DRW) and Root/Shoot Ratio of Dry Weight (RSR), were revealed existing significant difference among the DH lines. Using the constructed molecular linkage map from this segregating population, the QTL mapping was conducted among these three root parameters. MRL, DRW, and RSR were found being controlled by 2/1/2 QTLs respectively in JX17, 2/0/1 QTLs respectively in ZYQ8. Phenotype variance could be explained by 16.4% and 17.0% for MRL, 16.4% for DRW, 10.4% and 19.9% for RSR in JX17, 19.6% and 13.0% for MRL, 13.2% for RSR in ZYQ8. All these QTLs identified were distributed on rice chromosome 2, 3, 4, 5, 6, 9 and 10. Comparing with the other mapping results, one QTL for each trait (L169-CT106A for MRL, G45-G1314A for DRW, G62-G144 for RSR) was identical with the results reported previously.
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Li P, Xu JC. Total synthesis of cyclosporin O both in solution and in the solid phase using novel thiazolium-, immonium-, and pyridinium-type coupling reagents: BEMT, BDMP, and BEP. J Org Chem 2000; 65:2951-8. [PMID: 10814183 DOI: 10.1021/jo991687c] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Cyclosporin O (1), an extensively N-methylated immunosuppressive cyclic undecapeptide isolated from Tolypocladium inflatum Gams, was synthesized in 20-23% overall yield via 4 + 7 segment condensation and cyclization by the combined utilization of novel thiazolium- and immonium-type peptide coupling reagents 2-bromo-3-ethyl-4-methyl thiazolium tetrafluoroborate (BEMT) and 5-(1H-benzotriazol-1-yloxy)-3,4-dihydro-1-methyl 2H-pyrrolium hexachloroantimonate (BDMP) as well as compound 2-bromo-1-ethyl pyridinium tetrafluoroborate (BEP). BEMT and BEP, which have been proven to be very efficient for the coupling of peptide segments containing N-alkylated amino acid residues with respect to the fast reaction speed, low racemization, and high yields, were used to construct hindered amide bonds in CsO with the addition of HOAt, whereas the most efficient HOBt-derived immonium type reagent, BDMP, was used to perform the coupling of coded amino acids in CsO. Thus, the highly hindered protected 8-11 tetrapeptide 25 was successfully synthesized using BEMT in 65% yield, and the 1-7 heptapeptide 21 was obtained in 52-55% yield by the rationally combined utilization of BDMP, BEMT, and BEP. The synthesis of the linear undecapeptide 27 of CsO in the solid phase using BEMT and BEP was accomplished for the further evaluation of the effectiveness of these reagents.
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Li P, Xu JC. (1H-benzotriazol-1-yloxy)-N,N-dimethylmethaniminium hexachloroantimonate (BOMI), a novel coupling reagent for solution and solid-phase peptide synthesis. THE JOURNAL OF PEPTIDE RESEARCH : OFFICIAL JOURNAL OF THE AMERICAN PEPTIDE SOCIETY 2000; 55:110-9. [PMID: 10784027 DOI: 10.1034/j.1399-3011.2000.00158.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
A HOBt-based immonium-type compound,(1H-benzotriazol-1-yloxy)-N,N-dimethyl methaniminium hexachloroantimonate (BOMI), was synthesized and successfully applied to the synthesis of various oligopeptides with good yields. The estimation of racemization and the influence of several reaction parameters such as solvents, bases and temperature were studied by HPLC using a model reaction. It was found that the reactivity of BOMI was much higher than that of HOBt-based phosphonium- and uronium-type coupling reagents. Moreover, its racemization was lower than that of other HOBt-derived coupling reagents. The effectiveness of BOMI was also demonstrated by the synthesis of Leu-enkephalin both in solution and in the solid-phase.
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Hoffman M, Xu JC, Lesser M, Rai K. Cytotoxicity of 2-chlorodeoxadenosine (cladribine, 2-cdA) in combination with other chemotherapy drugs against two lymphoma cell lines. Leuk Lymphoma 1999; 33:141-5. [PMID: 10194131 DOI: 10.3109/10428199909093735] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Cladribine is a purine analog with impressive activity in patients with low-grade lymphoproliferative disorders. We studied the combination of cladribine with other antineoplastic drugs against two human-derived B-cell lymphoma cell lines in vitro. Cladribine was combined with cisplatin, daunorubicin, chlorambucil, paclitaxel or etoposide. Under the experimental conditions studied, only the combination of cladribine and cisplatin showed significantly increased cytotoxicity compared to the effect of either drug alone.
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Hoffman M, Xu JC, Smith C, Fanelli C, Pascal V, Degaetano C, Meenan G, Lehrer M, Lesser M, Citron M. A pharmacodynamic study of morphine and its glucuronide metabolites after single morphine dosing in cancer patients with pain. Cancer Invest 1997; 15:542-7. [PMID: 9412659 DOI: 10.3109/07357909709047595] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Eleven morphine naïve patients with cancer-related pain were given a single dose of either intravenous morphine (n = 5) or oral morphine (n = 6). Blood sampling was performed over a 24-hr period and serial pain assessments were made using a categorical scale. Plasma samples were analyzed for morphine, morphine-6-glucuronide (M-6-G), morphine-3-glucuronide (M-3-G), and normorphine using high-performance liquid chromatography. In neither the intravenous nor oral group was there a correlation between analgesia duration and the half-lives of morphine and M-6-G. There was no correlation between the time to peak analgesia and time to peak concentration for morphine or M-6-G. There was no significant difference in absolute concentrations of M-6-G or M-3-6 nor in the ratio of M-3-G to M-6-G at peak analgesia versus relapse.
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Maheswaran M, Subudhi PK, Nandi S, Xu JC, Parco A, Yang DC, Huang N. Polymorphism, distribution, and segregation of AFLP markers in a doubled haploid rice population. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 1997; 94:39-45. [PMID: 19352743 DOI: 10.1007/s001220050379] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/1996] [Accepted: 06/14/1996] [Indexed: 05/27/2023]
Abstract
We exploited the newly developed amplified fragment length polymorphism (AFLP) technique to study the polymorphism, distribution and inheritance of AFLP markers with a doubled haploid rice population derived from 'IR64'/'Azucena'. Using only 20 pairs of primer combinations, we detected 945 AFLP bands of which 208 were polymorphic. All 208 AFLP markers were mapped and distributed over all 12 chromosomes. When these were compared with RFLP markers already mapped in the population, we found the AFLP markers to be highly polymorphic in rice and to follow Mendelian segregation. As linkage map of rice can be generated rapidly with AFLP markers they will be very useful for marker-assisted backcrossing.
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Cao WW, Kao PN, Aoki Y, Xu JC, Shorthouse RA, Morris RE. A novel mechanism of action of the immunomodulatory drug, leflunomide: augmentation of the immunosuppressive cytokine, TGF-beta 1, and suppression of the immunostimulatory cytokine, IL-2. Transplant Proc 1996; 28:3079-80. [PMID: 8962191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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Xu JC, Vera DR, Stadalnik RC. Automatic preparation of radiopharmacokinetic data for in vivo estimation of receptor biochemistry. J Nucl Med 1996; 37:1896-902. [PMID: 8917199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
UNLABELLED We present a fully automated region of interest (ROI) and motion correction program for the generation of heart and liver time-activity data resulting from a hepatic functional imaging study using [99mTc-]galactosyl-neoglycoalbumin (99mTc-NGA). METHODS The program automatically draws heart and liver ROI and corrects for lateral movement of the subject. Eighty-four 99mTc-NGA studies, consisting of 32 healthy subjects and 52 patients with liver disease, were processed and submitted to an automated kinetic analysis that estimates the subject's asialoglycoprotein receptor concentration [R]o. RESULTS When compared to time-activity data generated by operator-drawn ROIs without motion correction, the average reduced Chi-square of the kinetic analysis decreased significantly (p < 0.001) from 2.20 to 1.37 and the number of studies that satisfied quality control increased from 74 to 81 studies. Receiver operating characteristic of [R]o resulted in greater detectability (0.984 +/- 0.012 compared with 0.965 +/- 0.020) when automatic ROI generation was employed. Using the test criteria of 0.65 microM, the sensitivity of [R]o increased from 0.88 to 0.92 and the specificity increased from 0.96 to 0.97. CONCLUSION Automated definition of liver and heart ROIs with motion correction, that reduces observational noise, increased the success rate of the radiopharmacokinetic analysis from 88% to 96%.
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Rathmell JC, Townsend SE, Xu JC, Flavell RA, Goodnow CC. Expansion or elimination of B cells in vivo: dual roles for CD40- and Fas (CD95)-ligands modulated by the B cell antigen receptor. Cell 1996; 87:319-29. [PMID: 8861915 DOI: 10.1016/s0092-8674(00)81349-5] [Citation(s) in RCA: 308] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Signals from CD4+ T cells induce two opposite fates in B cells: clonal proliferation of B cells that bind specifically to foreign antigens and clonal deletion of equivalent B cells that bind self-antigens. This B cell fate decision is determined by the concerted action of two surface proteins on activated T cells, CD40-and Fas-ligands (CD40L and FasL), whose effects are switched by signals from the B cell antigen receptor (BCR). Foreign antigens that stimulate the BCR acutely cause CD40L and FasL to promote clonal proliferation. CD40L and FasL trigger deletion, however, when the BCRs become desensitized by chronic stimulation with self-antigens or when BCRs have not bound an antigen. The need for both Fas and CD40L to correctly regulate self-reactive B cell fate may explain the severe autoantibody disorders in Fas- or CD40L-deficient children.
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Soong L, Xu JC, Grewal IS, Kima P, Sun J, Longley BJ, Ruddle NH, McMahon-Pratt D, Flavell RA. Disruption of CD40-CD40 ligand interactions results in an enhanced susceptibility to Leishmania amazonensis infection. Immunity 1996; 4:263-73. [PMID: 8624816 DOI: 10.1016/s1074-7613(00)80434-3] [Citation(s) in RCA: 250] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
To study the role of CD40 ligand (CD40L) in the host immune responses against intracellular pathogens, we infected CD40L knockout (CD40L-/-) mice with Leishmania amazonensis. Although wild-type mice were susceptible to infection and developed progressive ulcerative lesions, tissue parasite burdens in CD40L-/- mice were significantly higher. This heightened susceptibility to infection was associated with an impaired T cell and macrophage activation and altered inflammatory response, as reflected by low levels of IFN gamma, lymphotoxin-tumor necrosis factor (LT-TNF), and nitric oxide (NO) production. Furthermore, CD40L-/- mice failed to generate a protective immune response after immunization. These results indicate an essential role of cognate CD40-CD40L interactions in the generation of cellular immune responses against an intracellular parasite.
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Lytle C, Xu JC, Biemesderfer D, Forbush B. Distribution and diversity of Na-K-Cl cotransport proteins: a study with monoclonal antibodies. THE AMERICAN JOURNAL OF PHYSIOLOGY 1995; 269:C1496-505. [PMID: 8572179 DOI: 10.1152/ajpcell.1995.269.6.c1496] [Citation(s) in RCA: 297] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The Na-K-Cl cotransporter (NKCC) is present in most animal cells where it functions in cell volume homeostasis and epithelial salt transport. We developed six monoclonal antibodies (designated T4, T8, T9, T10, T12, and T14) against a fusion protein fragment encompassing the carboxy-terminal 310 amino acids of the human colonic NKCC. These T antibodies selectively recognized putative NKCC proteins in a diverse variety of animal tissues. Western blot analysis of membranes isolated from 23 types of cells identified single bands of immunoreactive protein ranging in mass from 146 to 205 kDa. The amount of immunoreactive protein detected in these cells correlated with loop diuretic binding site density. Proteins identified previously as Na-K-Cl cotransporters by loop diuretic photoaffinity labeling were mutually recognized by multiple T antibodies. Most of the T antibodies effectively immunoprecipitated the denatured form of the NKCC protein. Immunocytochemical studies on the rabbit parotid gland demonstrated that NKCC is restricted to the basolateral margin of the acinar cells and absent from the ducts, in accord with the central role of Na-K-Cl cotransport in chloride secretion. In the rabbit kidney, NKCC was localized to the apical membrane of thick ascending limb cells, consistent with its role in chloride reabsorption.
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