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J Xue

Publications and source records attributed to J Xue.

At least 109 records · Page 6Linked to original sources
PubMed1994

Determination of the disulfide bridges in factor Va heavy chain.

The M(r) = 94,000 heavy chain of bovine factor Va contains 10 cysteine residues which are distributed in the 2 A domains which make up this portion of the factor V molecule. The A1 domain contains four cysteines while the A2 domain contains six cysteines. The locations of disulfide bridges and free cysteines in bovine factor Va heavy chain were analyzed using iodo[14C]acetamide-labeled factor Va heavy chain digested with trypsin, plasmin, V-8 protease, and cyanogen bromide. Following HPLC separation of the resulting peptides, free cysteines were identified by the incorporation of radioactivity while disulfide-containing peptides were detected using an SBD-F fluorometric assay after reduction. All cysteine-containing peptides were analyzed by amino acid sequence analysis. The four cysteines in the A1 domain are associated with two disulfide bonds, Cys139-Cys165 and Cys220-Cys301. One disulfide bond was explicitly identified in the A2 domain; Cys471-Cys497, and a free cysteine was found in the A2 domain at Cys538. Significant difficulties were encountered in preparing identifiable or soluble peptides which would permit the explicit identification of the three remaining cysteines in the A2 domain. On the basis of homology, it is likely that Cys589 is a free SH while a disulfide bridge exists between Cys579 and Cys660. Thus, three major disulfide bonding patterns, characterized as "alpha", "beta", and "gamma" loops, are found in factor V. Each A domain contains a 26 residue "alpha loop at positions 139-165, 471-497, and 1684-1710. The A1 and A2 domains each contain 81 amino acid residue "beta" loops at 220-301 and 579-660.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1994

Contribution of the heavy and light chains of factor Va to the interaction with factor Xa.

The interactions of the isolated heavy and light chains of factor Va with factor Xa were evaluated using active-site-modified factor Xa [(carboxytetramethyl)rhodamine-Glu-Gly- Arg-factor Xa (ctr-EGR-Xa)]. The Kd for the factor Va heavy-chain interaction with ctr-EGR-Xa was 60 microM. A series of monoclonal antibodies directed against bovine factor Va were tested for their ability to inhibit thrombin formation in an assay using the fluorescent thrombin inhibitor dansylarginine N,N-(3-ethyl-1,5-pentanediyl)amide (DAPA). Monoclonal antibody alpha BFV-4, which recognizes the light chain of the cofactor, was found to inhibit the formation of thrombin. Similarly, monoclonal antibody alpha BFV-5, which is directed against the heavy chain of the cofactor, was found to inhibit thrombin formation. In contrast, monoclonal antibody alpha BFV-1, also directed against the heavy chain of the cofactor, did not inhibit thrombin generation by the prothrombinase complex. Monoclonal antibodies alpha BFV-4 and alpha BFV-5 inhibited the interaction of active-site-modified radiolabeled factor Xa (125I-Xa-EGR) with factor Va bound to PC/PS-coated microtiter wells, whereas nonimmune mouse IgG did not have any effect on the 125I-Xa-EGR.membrane-bound factor Va interaction. The antibodies effect upon the phospholipid-independent interaction between the cofactor and ctr-EGR-Xa was evaluated by analytical ultracentrifugation. Both alpha BFV-4 and alpha BFV-5 inhibited the phospholipid-independent interaction between factor Va and ctr-EGR-Xa.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1994

Sulfur dioxide and sodium metabisulfite induce bronchoconstriction in the isolated perfused and ventilated guinea pig lung via stimulation of capsaicin-sensitive sensory nerves.

In this study the relationship between sulfur dioxide-induced sensory nerve activation and acute bronchoconstriction was assessed. We also studied the effects of sodium metabisulfite, an agent that is suggested to increase airway resistance via activation of sensory nerves. Sulfur dioxide (250 ppm) induced a characteristic biphasic bronchoconstriction. Concomitantly sulfur dioxide induced the release of calcitonin gene-related peptide (CGRP) from capsaicin-sensitive sensory nerves into the pulmonary circulation. In lungs of guinea pigs pretreated with a neurotoxic dose of capsaicin, the first phase of bronchoconstriction was reduced and the overflow of CGRP was not detectable. Tetrodotoxin abolished the initial phase of the bronchoconstriction induced by sulfur dioxide, indicating that a local neural reflex depending on sodium channels was operant. Inhibition of the vanilloid receptor with capsazepine slightly, although not significantly, reduced the contractile responses to sulfur dioxide. Sodium metabisulfite, when infused via the pulmonary circulation (3 mM), induced bronchoconstriction which was abolished by capsaicin pretreatment, but not significantly reduced by capsazepine. The results indicate that in the isolated guinea pig lung inhaled sulfur dioxide induces initial bronchoconstriction in part via sensory nerve activation, while other mechanisms are involved in the late effect. Sensory nerve activation appears to be the only mechanism for bronchoconstriction induced by infused sodium metabisulfite. A role for sensory nerve-mediated bronchoconstriction by sulfur dioxide or sodium metabisulfite via activation of the vanilloid receptor could not be conclusively demonstrated by this study using capsazepine.

Animals↗
PubMed1994

[Transurethral non-contact laser treatment of prostatic hypertrophy].

66 cases of prostatic hypertrophy have been treated by transurethral non-contact Nd:YAG laser irradiation since April 1993. Sixty patients regained unobstructed urination within 1 week and 6 within 2 weeks after operation. The symptoms of the treated group were improved with the necrotic tissues gradually peeling off in 3 to 6 weeks. The short-term follow-up indicated that the prostatic gland distinctly reduced and residual urine decreased or vanished after treatment. Three patients had one of the following complications: urinary tract infection, epididymitis or urinous infiltration. These complications were treated appropriately. This therapy is ideal for the treatment of prostatic hypertrophy.

Aged↗
PubMed1993

Determination of the disulfide bridges in factor Va light chain.

The 74-kDa light chain of bovine factor Va is composed of three domains: the NH2-terminal A3 domain and the COOH-terminal C1 and C2 domains. In total, the light chain has eight cysteines: two in the A3 domain and three in each C domain. To determine the locations of the disulfide bridges, peptides were obtained from factor Va and iodo[1-14C]acetamide-labeled factor Va light chains by digestion with trypsin, activated protein C, lysylendopeptidase, and V8 protease. After HPLC purification, amino acid sequence and composition analyses showed that each domain of bovine Va light chain possesses a disulfide bond. The sites are Cys1684-Cys1710 (A3), Cys1866-Cys2020 (C1), and Cys2025-Cys2180 (C2). One free cysteine is located in each C domain, i.e., Cys1953 and Cys2100. The locations of the disulfide bonds in human Va and VIIIa light chains are anticipated to be similar to those of bovine Va light chain, because the cysteines involved are conserved.

Amino Acid Sequence↗
PubMed1993

Characterization of a Brassica napus myrosinase pseudogene: myrosinases are members of the BGA family of beta-glycosidases.

Myrosinase isoenzymes are known to be encoded by two different families of genes denoted MA and MB. Nucleotide sequence analysis of a Brassica napus genomic clone containing a gene for myrosinase revealed it to be a pseudogene of the MA family. The gene spans more than 5 kb and contains at least 12 exons. The exon sequence of the gene is highly similar to myrosinase cDNA sequences. However, the gene displays three potential or actual pseudogene characters. Southern blot analysis using probes from the 3' portions of the genomic and B. napus MA and MB cDNA clones showed that MA type myrosinases are encoded by approximately 4 genes, while MB type myrosinases are encoded by more than 10 genes in B. napus. Northern blots with mRNA from seeds and young leaves probed with the MA- and MB-specific probes showed that the MA and MB myrosinase gene families are differentially expressed. Myrosinases are highly similar to proteins of a beta-glycosidase enzyme family comprising both beta-glycosidases and phospho-beta-glycosidases of as diverged species as archaebacteria, bacteria, mammals and plants. By homology to these beta-glycosidases, putative active site residues in myrosinase are discussed on the basis of the similarity between beta-glycosidases and cellulases.

Amino Acid Sequence↗
PubMed1992

A judgment of attribution of increase in urine beta 2-microglobulin after environmental cadmium exposure.

Urine beta 2-microglobulin (beta 2-m) was measured in 433 persons with low-level, long-term environmental exposure to Cd, and in 124 control persons from unpolluted area. In 152 of the exposed persons, and some of the controls, the urine beta 2-m exceeded the limit. Of the 433 exposed persons, 74 cases with both urine Cd and beta 2-m exceeding the limit were matched by the control. This study suggests that after the stratification of the degrees of renal tubular injury according to the fractional beta 2-m excretion (FE beta 2-m) and coordination of clinical examination, FE beta 2-m could contribute to identifying renal tubular dysfunction due to Cd exposure and kidney lesion when both Cd exposure and original nephropathy exist.

Adult↗
PubMed1990

[Isolation and mapping of arbitrary single copy DNA fragment located on human chromosome 11p11-q11].

A library of genomic DNA has been constructed in EMBL3 lambda phage, from a Chinese hamster/human lymphocytes somatic cell hybrid carrying human chromosome 11 and 20. Recombinants containing human genomic DNA origin can be isolated from the hybrid cell genomic library by using species-specific probe. 8 single copy fragments have been isolated from 13 recombinants. One of them designated as FD11-1 has been identified on chromosome 11 by hybridized it with hybrid cell clone panel and mapped on chromosome 11p11-q11 by chromosome in situ hybridization. On chromosome 11, 3 linkage groups were reported, which located on 11p15, 11p13 and 11q13 respectively. Therefore, the FD11-1 will supply a new locus on chromosome 11 for linkage analysis. Endonuclease recognizing sites and potential recognizing sites on FD11-1 will guide the further RFLP studies.

Chromosome Mapping↗
PubMed1989

[The DNA content of bladder carcinoma in relation to pathologic grading, staging and prognosis: a flow cytometric study].

DNA ploidy analysis of 90 paraffin embedded specimens in bladder carcinoma were carried out by flow cytometry (FCM). Emphasis was paid on grade II tumors which usually have variable clinical course. DNA ploid level determined by FCM correlates highly with pathologic grade, stage, and prognosis of bladder carcinoma. Among grade II tumors, the patients with diploid and peridiploid carcinoma had a favourable prognosis whereas the patients with aneuploidy of high average DNA index had a bad prognosis, in particular, those with triploid and peritriploid tumors had poorer prognosis. DNA ploid level by which the prognosis of patients with bladder carcinoma is evaluated, appears to be more accurate than pathologic grade and clinical stage, particularly stage T0-T or grade II tumors. It therefore can serve as a tumor marker in bladder carcinomas.

Carcinoma, Transitional Cell↗
PubMedDate not supplied

Modeled estimates of chlorpyrifos exposure and dose for the Minnesota and Arizona NHEXAS populations.

This paper presents a probabilistic, multimedia, multipathway exposure model and assessment for chlorpyrifos developed as part of the National Human Exposure Assessment Survey (NHEXAS). The model was constructed using available information prior to completion of the NHEXAS study. It simulates the distribution of daily aggregate and pathway-specific chlorpyrifos absorbed dose in the general population of the State of Arizona (AZ) and in children aged 3-12 years residing in Minneapolis-St. Paul, Minnesota (MSP). Pathways included were inhalation of indoor and outdoor air, dietary ingestion, non-dietary ingestion of dust and soil, and dermal contact with dust and soil. Probability distributions for model input parameters were derived from the available literature, and input values were chosen to represent chlorpyrifos concentrations and demographics in AZ and MSP to the extent possible. When the NHEXAS AZ and MSP data become available, they can be compared to the distributions derived in this and other prototype modeling assessments to test the adequacy of this pre-NHEXAS model assessment. Although pathway-specific absorbed dose estimates differed between AZ and MSP due to differences in model inputs between simulated adults and children, the aggregate model results and general findings for simulated AZ and MSP populations were similar. The major route of chlorpyrifos intake was food ingestion, followed by indoor air inhalation. Two-stage Monte Carlo simulation was used to derive estimates of both inter-individual variability and uncertainty in the estimated distributions. The variability in the model results reflects the difference in activity patterns, exposure factors, and concentrations contacted by individuals during their daily activities. Based on the coefficient of variation, indoor air inhalation and dust ingestion were most variable relative to the mean, primarily because of variability in concentrations due to use or no-use of pesticides. Uncertainty analyses indicated a factor of 10-30 for uncertainty of model predictions of 10th, 50th, and 90th percentiles. The greatest source of uncertainty in the model stems from the definition of no household pesticide use as no use in the past year. Because chlorpyrifos persists in the residential environment for longer than a year, the modeled estimates are likely to be low. More information on pesticide usage and environmental concentrations measured at different post-application times is needed to refine and evaluate this and other pesticide exposure models.

Age Distribution↗
PubMedDate not supplied

[Impact of short-term increase in air pollution on mortality of the population].

The authors analyzed whether there is an association of mortality with ambient air pollution analyzed in Yekaterinburg and Nizhni Tagil in 1994 to 1997. There was a positive correlation between general mortality and CO or SO2 concentrations, between cardiovascular mortality and dust, NH3 or phenol, between mortality and CO or NH3. An increase of deaths as percents per 10 micrograms/m3 dust was calculated.

Air Pollutants↗
PubMedDate not supplied

Intercommunity differences in acid aerosol (H+)/sulfate (SO4(2-) ratios.

Exposures to acid aerosols have been associated with acute and chronic health effects. Beginning in 1988, extensive monitoring of acid aerosols (H+), sulfates (SO4(2-)), and ammonia (NH3) was conducted in 24 communities in the United States and Canada in order to characterize the seasonal and daily variations of these pollutants. More recently, in 1992 and 1993, summer monitoring of the same pollutants was conducted by Harvard researchers at multiple locations in Philadelphia, Pennsylvania to examine the factors causing spatial variation in the acidity levels in the greater metropolitan Philadelphia area. Earlier, a similar study also was conducted by Harvard in a more rural community, State College, Ohio, providing data on acidity, sulfate, and ammonia levels. In addition to these studies, New York University researchers have gathered substantial data on aerosol acidity, sulfates, and NH3 levels from sites in the New York City metropolitan region, Albany, Buffalo, and the Toronto metropolitan region between 1988 and 1992. This paper examines the relationships among H+, SO4(2-), ozone, and population density using summer measurements from sites in 24 cities across the United States and Canada, as well as Philadelphia, State College, the New York City region, Buffalo, and Albany. While past studies have consistently shown that H+ and SO4(2-) are correlated over time at sites in eastern North America, the results of our analysis show that spatial variations in the ratios of mean acid-to-sulfate levels also can be predicted satisfactorily with the use of either a linear or a quadratic model, once variations in population density are addressed (R2 = 0.6). These models may be useful in retrospective epidemiological investigations of acid aerosol exposures and health effects, using widely available sulfate measurements and data on local population size.

Acid Rain↗