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Gao X, Qian M, McGregor WG, Eaton JW. 193 CYTOTOXIC AND MUTAGENIC EFFECTS OF TOBACCO-BORNE FREE FATTY ACIDS. J Investig Med 2005. [DOI: 10.2310/6650.2005.00006.192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Lu Y, Bu L, Zhou S, Jin M, Sundberg JP, Jiang H, Qian M, Shi Y, Zhao G, Kong X, Hu L. Scd1ab-Xyk: a new asebia allele characterized by a CCC trinucleotide insertion in exon 5 of the stearoyl-CoA desaturase 1 gene in mouse. Mol Genet Genomics 2004; 272:129-37. [PMID: 15278437 DOI: 10.1007/s00438-004-1043-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2004] [Accepted: 07/01/2004] [Indexed: 10/26/2022]
Abstract
We describe here a spontaneous, autosomal recessive mutant mouse suffering from skin and hair defects, which arose in the outbred Kunming strain. By haplotype analysis and direct sequencing of PCR products, we show that this mutation is a new allele of the asebia locus with a naturally occurring mutation in the Scd1 gene (a CCC insertion at nucleotide position 835 in exon 5), which codes for stearoyl-CoA desaturase 1. This mutation introduces an extra proline residue at position 279 in the Scd1 protein. The mutant mice, originally designated km/km but now assigned the name Scd1ab-Xyk (hereafter abbreviated as abXyk/abXyk), have a similar gross and histological phenotype to that reported for previously characterized allelic asebia mutations (Scd1ab, Scd1abJ, Scd1ab2J, and Scd1tm1Ntam). Histological analysis showed they were also characterized by hypoplasic sebaceous glands and abnormal hair follicles. In a cross between Kunming- abXyk/abXyk and ABJ/Le-abJ/abJ mice, all the progeny showed the same phenotype, indicating that the two mutations were non-complementing and therefore allelic. Comparisons with the other four allelic mutants indicate that the Scd1ab-Xyk mutation causes the mildest change in Scd1 function. This new mouse mutant is a good model not only for the study of scarring alopecias in humans, which are characterized by hypoplasic sebaceous glands, but also for studying the structure and function of the Scd1 protein.
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Qian M, Zhang XH, Mei B, Zhang P, Yan Z, Yu M. [Cytotoxic effect of Acanthamoeba trophozoite on HeLa cells]. ZHONGGUO JI SHENG CHONG XUE YU JI SHENG CHONG BING ZA ZHI = CHINESE JOURNAL OF PARASITOLOGY & PARASITIC DISEASES 2003; 19:37-40. [PMID: 12572022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
Abstract
OBJECTIVE To investigate the cytotoxic effect(CTE) on human cervix cancer HeLa cells induced by five strains of pathogenic free-living Acanthamoeba. METHODS The cytotoxic effect of five isolates of Acanthamoeba on HeLa cells was investigated by light microscopy and MTT method. RESULTS The photomicrographs of HeLa cells showed a sequence of cardinal morphological features of apoptosis when HeLa cells were exposed to Acanthamoeba in a time-dependent manner at a ratio of 1:1 for 12 h. MTT method showed more than 50% of tumor cells underwent cytolysis following exposure to A. lugdunensis trophozoites, and only 18% of cells treated with A. polyphaga underwent CTE. The CTE produced by A. lugdunensis and A. quina trophozoites was more rapid than the others, beginning as early as 6 h after coincubation and resulting in cytolysis by 72 h. CONCLUSION These five strains of Acanthamoeba exhibit cytotoxic effects of varying degrees on HeLa cells, inducing apoptosis.
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Akervall J, Guo X, Qian M, Schoumans J, Yuhas J, Carey T, Leeser B, Bradford C, Tennvall J, Teh B. 106 Genetic and expression profiles of squamous cell carcinoma of the head and neck correlate with cisplatin sensitivity and resistance in cell lines and patients. EJC Suppl 2003. [DOI: 10.1016/s1359-6349(03)90139-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
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Qian M, Reineccius G. Static Headspace and Aroma Extract Dilution Analysis of Parmigiano Reggiano Cheese. J Food Sci 2003. [DOI: 10.1111/j.1365-2621.2003.tb08244.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Klesk K, Qian M. Preliminary Aroma Comparison of Marion (Rubus spp. hyb) and Evergreen (R. laciniatus L.) Blackberries by Dynamic Headspace/OSME Technique. J Food Sci 2003. [DOI: 10.1111/j.1365-2621.2003.tb05734.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Feldman AL, Costouros NG, Wang E, Qian M, Marincola FM, Alexander HR, Libutti SK. Advantages of mRNA amplification for microarray analysis. Biotechniques 2002; 33:906-12, 914. [PMID: 12398200 DOI: 10.2144/02334mt04] [Citation(s) in RCA: 127] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Expanding applications of cDNA microarrays such as fine needle aspiration biopsy and laser capture microdissection necessitate the ability to perform arrays with minute starting amounts of RNA. While methods for amplifying RNA have been advocated, the fidelity of array results using amplified material has not been fully validated. Here we demonstrate preserved fidelity in arrays using one or two rounds of mRNA amplification, validated by downstream real-time quantitative PCR. In addition, the quality of the array data was superior to that obtained using total RNA. Based on these results, we recommend routine mRNA amplification for all cDNA microarray-based analysis of gene expression.
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Zogakis TG, Costouros NG, Kruger EA, Forbes S, He M, Qian M, Feldman AL, Figg WD, Alexander HR, Liu ET, Kohn EC, Libutti SK. Microarray gene expression profiling of angiogenesis inhibitors using the rat aortic ring assay. Biotechniques 2002; 33:664-6, 668, 670. [PMID: 12238776 DOI: 10.2144/02333dd02] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The rat aortic ring assay has been previously described as a useful ex vivo model for analyzing the biological activity of various inhibitors of angiogenesis. Rat aortic rings are exposed to antiangiogenic agents for a five-day incubation period. Then, the degree of microvessel outgrowth from the rings is analyzed and quantified. In contrast to most in vitro angiogenesis assays, the rat aortic ring model provides a unique microenvironment to evaluate the interaction of various cell types and biological factors for their influence on angiogenesis. Microarray analysis is an accepted method for the evaluation of gene expression profiles and can be used to better understand changes in gene expression that occur when rat aortic rings are exposed to a particular biological agent. Here we describe a method of using microarray technology to evaluate the modulation of gene expression in angiogenesis using the rat aortic ring assay.
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Qian M, Reineccius G. Identification of aroma compounds in Parmigiano-Reggiano cheese by gas chromatography/olfactometry. J Dairy Sci 2002; 85:1362-9. [PMID: 12146465 DOI: 10.3168/jds.s0022-0302(02)74202-1] [Citation(s) in RCA: 122] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The volatile compounds in Parmigiano-Reggiano cheese were isolated by solvent extraction/high vacuum distillation, followed by separation into acidic, basic, water-soluble, and neutral fractions. The neutral fraction was further fractionated by a normal-phase liquid chromatography. Aroma compounds were identified using gas chromatography/Osme-mass spectrometry and confirmed with retention index of standards. Butanoic, hexanoic, octanoic, and decanoic acids are the major free fatty acids contributing to cheesy, lipolyzed aroma. Ethyl butanoate, ethyl hexanoate, ethyl octanoate, ethyl propanoate, ethyl pentanoate, ethyl heptanoate, and ethyl decanoate are the major esters contributing to fruity aroma. 2-Methylbutanal, 3-methylbutanal, 2,4-hexadienal, 2-butenal, pentanal, hexanal, heptanal, diacetyl, phenylacetaldehyde, dimethyltrisulfide, and methional were identified to be odor-active. It was found that 2,3-dimethylpyrazine, 2,6-dimethyl-pyrazine, 2,5-dimethyl-3-ethylpyrazine, trimethyl-pyrazine, 5-ethyl-2-methylpyridine, 2,3-dimethyl-5-ethylpyrazine, 2,3,5-trimethyl-6-ethyl-pyrazine, furfural, and 2-furanmethanol contribute to the nutty, roasted aroma in this cheese.
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Xue CB, He X, Corbett RL, Roderick J, Wasserman ZR, Liu RQ, Jaffee BD, Covington MB, Qian M, Trzaskos JM, Newton RC, Magolda RL, Wexler RR, Decicco CP. Discovery of macrocyclic hydroxamic acids containing biphenylmethyl derivatives at P1', a series of selective TNF-alpha converting enzyme inhibitors with potent cellular activity in the inhibition of TNF-alpha release. J Med Chem 2001; 44:3351-4. [PMID: 11585440 DOI: 10.1021/jm0155502] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
SAR exploration at P1' using an anti-succinate-based macrocyclic hydroxamic acid as a template led to the identification of several bulky biphenylmethyl P1' derivatives which confer potent porcine TACE and anti-TNF-alpha cellular activities with high selectivity versus most of the MMPs screened. Our studies demonstrate for the first time that TACE has a larger S1' pocket in comparison to MMPs and that potent and selective TACE inhibitors can be achieved by incorporation of sterically bulky P1' residues.
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Yao W, Wasserman ZR, Chao M, Reddy G, Shi E, Liu RQ, Covington MB, Arner EC, Pratta MA, Tortorella M, Magolda RL, Newton R, Qian M, Ribadeneira MD, Christ D, Wexler RR, Decicco CP. Design and synthesis of a series of (2R)-N(4)-hydroxy-2-(3-hydroxybenzyl)-N(1)- [(1S,2R)-2-hydroxy-2,3-dihydro-1H-inden-1-yl]butanediamide derivatives as potent, selective, and orally bioavailable aggrecanase inhibitors. J Med Chem 2001; 44:3347-50. [PMID: 11585439 DOI: 10.1021/jm015533c] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A pharmacophore model of the P1' site, specific for aggrecanase, was defined using the specificity studies of the matrix metalloproteinases and the similar biological activity of aggrecanase and MMP-8. Incorporation of the side chain of a tyrosine residue into compound 1 as the P1' group provided modest selectivity for aggrecanase over MMP-1, -2, and -9. A cis-(1S)(2R)-amino-2-indanol scaffold was incorporated as a tyrosine mimic (P2') to conformationally constrain 2. Further optimization resulted in compound 11, a potent, selective, and orally bioavailable inhibitor of aggrecanase.
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Telang S, Vimr E, Mahoney JR, Law I, Lundqvist-Gustafsson H, Qian M, Eaton JW. Strain-specific iron-dependent virulence in Escherichia coli. J Infect Dis 2001; 184:159-65. [PMID: 11424012 DOI: 10.1086/322017] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2000] [Revised: 03/30/2001] [Indexed: 11/03/2022] Open
Abstract
For reasons unknown, certain Escherichia coli strains become highly virulent when injected with hemoglobin or other soluble iron sources. Two clinical isolates (virulent and nonvirulent) showed equivalent hemoglobin-mediated growth acceleration in vitro. However, when injected intraperitoneally into mice without hemoglobin, the virulent strain was cleared more slowly (t(1/2), >4 h vs. <30 min). The virulent E. coli strain had a polysialic acid-containing capsule, whereas the nonvirulent strain did not. Virulent E. coli grown at 20 degrees C (which blocks polysialylation) were cleared as rapidly as nonvirulent organisms. In another virulent E. coli strain having abundant outer membrane polysialic acid, targeted deletion of the polysialyltransferase accelerated host clearance and blocked iron-dependent virulence. The iron-dependent virulence of certain E. coli strains may represent the combined effect of slow in vivo clearance-associated, in this case, with outer membrane polysialylation coupled with accelerated growth permitted by iron compounds.
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Zhu G, Huang Q, Qian M, Tang Y. Crystal structure of alpha-momorcharin in 80% acetonitrile--water mixture. BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1548:152-8. [PMID: 11451448 DOI: 10.1016/s0167-4838(01)00235-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Crystals of alpha-momorcharin (MMC) were cross-linked and soaked in an 80% acetonitrile--water mixture and X-ray data were collected to 2.2 A resolution. MMC is a ribosome-inactivating protein with a sugar chain on Asn-227. In previous studies, the whole conformation of the sugar chain could not be obtained in the aqueous system. Here the structure of MMC in a low water system is shown to be similar to the native one, but the sugar chain on Asn-227 is defined by the electron density map. Several oxygen atoms of the oligosaccharide formed intramolecular hydrogen bonds to the protein moiety. The conformation of the residues in the active center is similar to that in the aqueous system. Our results show conformational alteration of the tetrasaccharide of MMC in organic media. They indicate that the oligosaccharides are more rigid in organic solvents. X-ray determination in organic media may be used to solve some structures of oligosaccharides linked to glycoproteins.
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Zhang Z, Qian M, Huang Q, Jia Y, Tang Y, Wang K, Cui D, Li M. Crystal structure of the complex of concanavalin A and hexapeptide. JOURNAL OF PROTEIN CHEMISTRY 2001; 20:423-9. [PMID: 11732694 DOI: 10.1023/a:1012289022412] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The X-ray structure analysis of a cross-linked crystal of concanavalin A soaked with a hexapeptide molecule as a probe molecule showed an electron density corresponding to full occupation in the binding pocket. The site lies on the surface of concanavalin A and is surrounded by three symmetry-related molecules. The crystal structure of the hexapeptide complex was refined at 1.93-A resolution, to an R-factor of 19% (Rfree factor of 25%), with an RMS deviation in bond distances of 0.01 A. The model includes all 237 residues of concanavalin A, one manganese ion, one calcium ion, 95 water molecules, one glutaraldehyde molecule, one isopropanol molecule, and one hexapeptide molecule. This X-ray structure analysis also provides an approach to mapping the binding surface of crystalline protein with a probe molecule that is dissolved in the mixture of organic solvent with water or in neat organic solvent but is hardly dissolved in aqueous solution.
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Tang Y, Bu X, Yao Q, Xie Q, Qian M, Hu Y, Yu Y. [Audiological findings of the aging across the urban and rural of Suzhou]. LIN CHUANG ER BI YAN HOU KE ZA ZHI = JOURNAL OF CLINICAL OTORHINOLARYNGOLOGY 2001; 15:315-7. [PMID: 12541792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
Abstract
OBJECTIVE To determine the epidemiological characteristics of old people's hearing. METHOD Questionnaires, physical examination, audiometry and bio-chemical tests were performed on the elders above 60 years old in part of the urban and rural area of Suzhou with random sample survey. RESULT A total of 1,040 individuals was investigated, among which 505 were from urban, and 535 were from rural. 33 of 505 senior citizen (6.53%) were nososacusis, 282 (55.84%) were presbycusis and 21 (4.16%) were noise-induced deafness; In the rural area, 35 of 535 (6.54%) were nososacusis, 232 (43.36%) were presbycusis, and 4 (0.75%) were noise deafness. There was significant difference of the incidence of presbycusis between urban and rural. The audiometric thresholds chart manifested that the threshold elevated with age increasing especially in high-frequency. CONCLUSION The etiology of hearing loss of elders was mainly due to presbycusis. The higher incidence of psychotic disorder in urban probably caused a correspondingly higher incidence of presbycusis. So the prevention and cure of some age-induced diseased (e.g. hypertension, arteriosclerosis and diabetes) may be helpful to release and improve presbycusis.
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Qian M, Nahoum V, Bonicel J, Bischoff H, Henrissat B, Payan F. Enzyme-catalyzed condensation reaction in a mammalian alpha-amylase. High-resolution structural analysis of an enzyme-inhibitor complex. Biochemistry 2001; 40:7700-9. [PMID: 11412124 DOI: 10.1021/bi0102050] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Mammalian alpha-amylases catalyze the hydrolysis of alpha-linked glucose polymers according to a complex processive mechanism. We have determined the X-ray structures of porcine pancreatic alpha-amylase complexes with the smallest molecule of the trestatin family (acarviosine-glucose) which inhibits porcine pancreatic alpha-amylase and yet is not hydrolyzed by the enzyme. A structure analysis at 1.38 A resolution of this complex allowed for a clear identification of a genuine single hexasaccharide species composed of two alpha-1,4-linked original molecules bound to the active site of the enzyme. The structural results supported by mass spectrometry experiments provide evidence for an enzymatically catalyzed condensation reaction in the crystal.
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Xiao S, Bu L, Zhu L, Zheng G, Yang M, Qian M, Hu L, Liu J, Zhao G, Kong X. A new locus for hereditary gingival fibromatosis (GINGF2) maps to 5q13-q22. Genomics 2001; 74:180-5. [PMID: 11386754 DOI: 10.1006/geno.2001.6542] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Gingival fibromatosis (GINGF) is an oral disorder characterized by enlargement of the gingiva. It occurs either as the sole phenotype or combined with other symptoms. Thus far, one GINGF locus has been mapped on chromosome 2, at 2p21, and a second possible locus has been mapped to 2p13. However, the genes responsible for this disorder have not been elucidated. We identified a four-generation Chinese GINGF family in which the disease manifests within 1 year after birth. After exclusion of the two known GINGF loci in this family, we performed a genome-wide search to map the chromosome location of the responsible gene. We identified a new locus, GINGF2, on chromosome 5q13-q22 with a maximum two-point lod score of 4.31 at D5S1721 (theta = 0.00). Haplotype analysis placed the critical region in the interval defined by D5S1491 and D5S1453. Within this region, calcium/calmodulin-dependent protein kinase IV (CAMK4) is a strong candidate.
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Zhang Z, Qian M, Wang H, Li Y. Transcatheter closure in 354 pediatric cases of patent ductus arteriosus using five different devices. Chin Med J (Engl) 2001; 114:456-8. [PMID: 11780402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2023] Open
Abstract
OBJECTIVE To assess the effect of transcatheter closure of patent ductus arteriosus (PDA) by comparing five different devices. METHODS 354 patients (135 males, 219 females) underwent transcatheter closure of PDA using the Porstmann Ivalon plug, Rashkind double umbrella, Sideris button device, Coils and Amplatzer occluders. The mean PDA diameter at its narrowest segment was 3.1 +/- 1.3 mm. Qp/Qs was 2.2 +/- 0.5. Follow-up evaluation was performed with color flow mapping of the main pulmonary artery at 24 h and 6 months after closure. RESULTS Successful occlusion was observed in 92% (23/25) for the Porstmann device, 98.7% (77/78) for the Rashkind device, 100% (43/43) for the Sideris device, 100% (69/69) for the Coil and 100% (139/139) for the Amplatzer device. No residual shunts were needed for the Porstmann, while 1.4%-15% of patients who received the Rashkind, Sideris, Coils or Amplatzer needed residual shunts during follow-up. There were complications of 24% (6/25) for the Porstmann, 3.8% (3/78) for the Rashkind, 1.4% (1/69) for Coils and 1.4% (2/139) for the Amplatzer. No complications were found in patients with the Sideris device. CONCLUSION The results showed that the Sideris device, Coils and the Amplatzer device are more effective and safer than the others for the occlusion of PDA in children.
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Xia G, Qian M. The relationship of parenting style to self-reported mental health among two subcultures of Chinese. J Adolesc 2001; 24:251-60. [PMID: 11437483 DOI: 10.1006/jado.2001.0375] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The results of this investigation with 127 youths (aged 16-22 years) from mainland China supported the association of recalled parent's styles (assessed by the EMBU) with adolescents' self-evaluated health status (measured by the SCL-90). Many psychosomatic symptoms and lower scores on indexes of general mental health were significantly related to higher levels of parental rejection and denial, punishing tendency, overprotection and overinvolvement and to lower levels of parental emotional warmth and comprehension. The association between parenting style and mental health status of adolescents can be generalized across genders and across the two Chinese subcultures studied (Han and Kejia ethnical groups) with moderate to fairly high confidence. The mental health status of participants suggests some differences between different subcultures or genders on several variables of the SCL-90.
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Duda D, Tu C, Qian M, Laipis P, Agbandje-McKenna M, Silverman DN, McKenna R. Structural and kinetic analysis of the chemical rescue of the proton transfer function of carbonic anhydrase II. Biochemistry 2001; 40:1741-8. [PMID: 11327835 DOI: 10.1021/bi002295z] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Histidine 64 in human carbonic anhydrase II (HCA II) functions in the catalytic pathway of CO(2) hydration as a shuttle to transfer protons between the zinc-bound water and bulk water. Catalysis of the exchange of (18)O between CO(2) and water, measured by mass spectrometry, is dependent on this proton transfer and was decreased more than 10-fold for H64A HCA II compared with wild-type HCA II. The loss of catalytic activity of H64A HCA II could be rescued by 4-methylimidazole (4-MI), an exogenous proton donor, in a saturable process with a maximum activity of 40% of wild-type HCA II. The crystal structure of the rescued complex at 1.6 A resolution shows 4-MI bound in the active-site cavity of H64A HCA II, through pi stacking interactions with Trp 5 and H-bonding interactions with water molecules. In this location, 4-MI is about 12 A from the zinc and approximates the observed "out" position of His 64 in the structure of the wild-type enzyme. 4-MI appears to compensate for the absence of His 64 and rescues the catalytic activity of the H64A HCA II mutant. This result strongly suggests that the out conformation of His 64 is effective in the transfer of protons between the zinc-bound solvent molecule and solution.
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Xiao S, Yu C, Chou X, Yuan W, Wang Y, Bu L, Fu G, Qian M, Yang J, Shi Y, Hu L, Han B, Wang Z, Huang W, Liu J, Chen Z, Zhao G, Kong X. Dentinogenesis imperfecta 1 with or without progressive hearing loss is associated with distinct mutations in DSPP. Nat Genet 2001; 27:201-4. [PMID: 11175790 DOI: 10.1038/84848] [Citation(s) in RCA: 235] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Dentinogenesis imperfecta 1 (DGI1, MIM 125490) is an autosomal dominant dental disease characterized by abnormal dentin production and mineralization. The DGI1 locus was recently refined to a 2-Mb interval on 4q21 (ref. 1). Here we study three Chinese families carrying DGI1. We find that the affected individuals of two families also presented with progressive sensorineural high-frequency hearing loss (gene DFNA39). We identified three disease-specific mutations within the dentin sialophosphoprotein gene (DSPP) in these three families. We detected a G-->A transition at the donor-splicing site of intron 3 in one family without DFNA39, a mutation predicted to result in the skipping of exon 3. In two other families affected with both DGI1 and DFNA39, however, we identified two independent nucleotide transversions in exons 2 and 3 of DSPP, respectively, that cause missense mutations of two adjacent amino-acid residues in the predicted transmembrane region of the protein. Moreover, transcripts of DSPP previously reported to be expressed specifically in teeth are also detected in the inner ear of mice. We have thus demonstrated for the first time that distinct mutations in DSPP are responsible for the clinical manifestations of DGI1 with or without DFNA39.
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Felix K, Kovalchuk AL, Park SS, Coleman AE, Ramsay ES, Qian M, Kelliher KA, Jones GM, Ried T, Bornkamm GW, Janz S. Inducible mutagenesis in TEPC 2372, a mouse plasmacytoma cell line that harbors the transgenic shuttle vector lambdaLIZ. Mutat Res 2001; 473:121-36. [PMID: 11166031 DOI: 10.1016/s0027-5107(00)00143-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The plasmacytoma cell line, TEPC 2372, was derived from a malignant plasma cell tumor that developed in the peritoneal cavity of a BALB/c mouse that harbored the transgenic shuttle vector for the assessment of mutagenesis in vivo, lambdaLIZ. TEPC 2372 was found to display the typical features of a BALB/c plasmacytoma. It consisted of pleomorphic plasma cells that secreted a monoclonal immunoglobulin (IgG2b/lambda), was initially dependent on the presence of IL-6 to grow in cell culture, contained a hyperdiploid chromosome complement with a tendency to undergo tetraploidization, and harbored a constitutively active c-myc gene by virtue of a T(6;15) chromosomal translocation. TEPC 2372 was further characterized by the ability to respond to in vitro exposure with 4-NQO (4-nitroquinoline-1-oxide), an oxidative model mutagen, with a vigorous dose-dependent increase in mutagenesis that peaked at a 7.85-fold elevation of mutant rates in lambdaLIZ when compared to background mutant rates in untreated controls. Cotreatment with 4-NQO and BSO (buthionine sulfoximine), a glutathione-depleting compound that causes endogenous oxidative stress, resulted in a 9.03-fold increase in the mutant frequency in lambdaLIZ. These results demonstrated that TEPC 2372, the malignant plasma cell counterpart of the lambdaLIZ-based in vivo mutagenesis assay, may be useful as an in vitro reference point for the further elucidation of oxidative mutagenesis in lymphoid tissues.
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Zhao X, Yang Z, Qian M, Zhu X. Interactions among subunits of human Arp2/3 complex: p20-Arc as the hub. Biochem Biophys Res Commun 2001; 280:513-7. [PMID: 11162547 DOI: 10.1006/bbrc.2000.4151] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The Arp2/3 complex is critical for nucleation and crosslinking of actin filaments. To gain insight into its subunit topology and assembly pathway, we systematically examined interactions among subunits of human Arp2/3 complex by yeast two-hybrid assays. It was shown that p20-Arc was able to interact with p21-Arc, p34-Arc, and p16-Arc, respectively. In contrast, p41-Arc only interacted with p20-Arc/p16-Arc heterodimer. In addition, we found that structural integrity was important for association between p20-Arc and p21-Arc, while the N-terminal half of p34-Arc was dispensable for its binding to p20-Arc. Our data suggest a key role of p20-Arc and a multistep pathway for the complex formation.
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Zhang Z, Qian M, Huang Q, Jia Y, Tang Y, Wang K, Cui D, Li M. Crystal structure of the complex of concanavalin A and tripeptide. JOURNAL OF PROTEIN CHEMISTRY 2001; 20:59-65. [PMID: 11330349 DOI: 10.1023/a:1011053330536] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The X-ray structure analysis of a cross-linked crystal of concanavalin A soaked with the tripeptide molecule as the probe molecule showed electron density corresponding to full occupation in the binding pocket. The site lies on the surface of concanavalin A and is surrounded by three symmetry-related molecules. The crystal structure of the tripeptide complex was refined at 2.4-A resolution to an R-factor of 17.5%, (Rfree factor of 23.7%), with an RMS deviation in bond distances of 0.01 A. The model includes all 237 residue of concanavalin A, 1 manganese ion, 1 calcium ion, 161 water molecules, 1 glutaraldehyde molecule, and 1 tripeptide molecule. This X-ray structure analysis also provides an approach to mapping the binding surface of crystalline protein with a probe molecule that is dissolved in a mixture of organic solvent with water or in neat organic solvent but is hardly dissolved in aqueous solution.
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Garner B, Roberg K, Qian M, Eaton JW, Truscott RJ. Distribution of ferritin and redox-active transition metals in normal and cataractous human lenses. Exp Eye Res 2000; 71:599-607. [PMID: 11095912 DOI: 10.1006/exer.2000.0912] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Previous studies have shown that lenticular levels of Fe and Cu are elevated in age-related cataract. However, it is not known if these metals are present in a state that is permissive for redox reactions that may lead to the formation of free radicals. In addition, there is little data available concerning the concentration and lenticular distribution of ferritin, the major intracellular Fe-sequestering protein, in the lens. The aim of the present work was therefore to determine the distribution of ferritin and the redox-availability of Fe and Cu in healthy and cataractous lenses. Lens ferritin distribution was assessed by ELISA and immunohistochemistry. A modified ELISA detected ferritin in an 'insoluble' lens protein fraction. Ferritin levels were not significantly different in the cortex vs nucleus of healthy lenses. In contrast, ferritin levels in the cataractous lens nuclei appeared to be 70% lower compared to the cortex. This was at least partially due to the presence of ferritin within an insoluble protein fraction of the homogenized lenses. In normal lenses, ferritin staining was most intense in the epithelium, with diffuse staining observed throughout the cortex and nucleus. The redox-availability of lenticular metals was determined using: (1) autometallography; (2) Ferene-S as a chromogenic Fe chelator; and (3) NO release from nitrosocysteine to probe for redox-active Cu. The autometallography studies showed that the cataractous lenses stained more heavily for redox-active metals in both the nucleus and cortex when compared to age-matched control lenses. Chelatable Fe was detected in homogenized control lenses after incubation with Ferene-S, with almost three-fold higher levels detected in the cataractous lenses on average. The Cu-catalysed liberation of NO from added nitrosocysteine was not demonstrated in any lens sample. When exogenous Cu (50 n M) was added to the lenses, it was rapidly chelated. The cataractous samples were approximately twice as effective at redox-inactivation of added Cu. These studies provide evidence that a chelatable pool of potentially redox-active Fe is present at increased concentrations in human cataractous lenses. In contrast, it seems that lenticular Cu may not be readily available for participation in redox reactions.
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