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151.
Lucas A Salas Cristina M Villanueva Salman M Tajuddin André F S Amaral Agustín F Fernandez Lee E Moore Alfredo Carrato Adonina Tardón Consol Serra Reina García-Closas Xavier Basaga?a Nathaniel Rothman Debra T Silverman Kenneth P Cantor Manolis Kogevinas Francisco X Real Mario F Fraga Núria Malats 《Epigenetics》2014,9(11):1532-1539
DNA methylation changes contribute to bladder carcinogenesis. Trihalomethanes (THM), a class of disinfection by-products, are associated with increased urothelial bladder cancer (UBC) risk. THM exposure in animal models produces DNA hypomethylation. We evaluated the relationship of LINE-1 5-methylcytosine levels (LINE-1%5mC) as outcome of long-term THM exposure among controls and as an effect modifier in the association between THM exposure and UBC risk. We used a case-control study of UBC conducted in Spain. We obtained personal lifetime residential THM levels and measured LINE-1%5mC by pyrosequencing in granulocyte DNA from blood samples in 548 incident cases and 559 hospital controls. Two LINE-1%5mC clusters (above and below 64%) were identified through unsupervised hierarchical cluster analysis. The association between THM levels and LINE-1%5mC was evaluated with β regression analyses and logistic regression was used to estimate odds ratios (OR) adjusting for covariables. LINE-1%5mC change between percentiles 75th and 25th of THM levels was 1.8% (95% confidence interval (CI): 0.1, 3.4%) among controls. THM levels above vs. below the median (26 μg/L) were associated with increased UBC risk, OR = 1.86 (95% CI: 1.25, 2.75), overall and among subjects with low levels of LINE-1%5mC (n = 975), OR = 2.14 (95% CI: 1.39, 3.30), but not associated with UBC risk among subjects’ high levels of LINE-1%5mC (n = 162), interaction P = 0.03. Results suggest a positive association between LINE-1%5mC and THM levels among controls, and LINE-1%5mC status may modify the association between UBC risk and THM exposure. Because reverse causation and chance cannot be ruled out, confirmation studies are warranted. 相似文献
152.
Qian Xiao Steven C. Moore Simina M. Boca Charles E. Matthews Nathaniel Rothman Rachael Z. Stolzenberg-Solomon Rashmi Sinha Amanda J. Cross Joshua N. Sampson 《PloS one》2014,9(5)
Background
The application of metabolomics in epidemiological studies would potentially allow researchers to identify biomarkers associated with exposures and diseases. However, within-individual variability of metabolite levels caused by temporal variation of metabolites, together with technical variability introduced by laboratory procedures, may reduce the study power to detect such associations. We assessed the sources of variability of metabolites from urine samples and the implications for designing epidemiologic studies.Methods
We measured 539 metabolites in urine samples from the Navy Colon Adenoma Study using liquid chromatography-mass spectrometry (LC-MS) and gas chromatography-mass spectroscopy (GC-MS). The study collected 2–3 samples per person from 17 male subjects (age 38–70) over 2–10 days. We estimated between-individual, within-individual, and technical variability and calculated expected study power with a specific focus on large case-control and nested case-control studies.Results
Overall technical reliability was high (median intraclass correlation = 0.92), and for 72% of the metabolites, the majority of total variance can be attributed to between-individual variability. Age, gender and body mass index explained only a small proportion of the total metabolite variability. For a relative risk (comparing upper and lower quartiles of “usual” levels) of 1.5, we estimated that a study with 500, 1,000, and 5,000 individuals could detect 1.0%, 4.5% and 75% of the metabolite associations.Conclusions
The use of metabolomics in urine samples from epidemiological studies would require large sample sizes to detect associations with moderate effect sizes. 相似文献153.
154.
T B Price D Laurent K F Petersen D L Rothman G I Shulman 《Journal of applied physiology》2000,88(2):698-704
This study compared muscle glycogen recovery after depletion of approximately 50 mmol/l (DeltaGly) from normal (Nor) resting levels (63.2 +/- 2.8 mmol/l) with recovery after depletion of approximately 50 mmol/l from a glycogen-loaded (GL) state (99.3 +/- 4.0 mmol/l) in 12 healthy, untrained subjects (5 men, 7 women). To glycogen load, a 7-day carbohydrate-loading protocol increased muscle glycogen 1.6 +/- 0.2-fold (P < or = 0.01). GL subjects then performed plantar flexion (single-leg toe raises) at 50 +/- 3% of maximum voluntary contraction (MVC) to yield DeltaGly = 48.0 +/- 1.3 mmol/l. The Nor trial, performed on a separate occasion, yielded DeltaGly = 47.5 +/- 4.5 mmol/l. Interleaved natural abundance (13)C-(31)P-NMR spectra were acquired and quantified before exercise and during 5 h of recovery immediately after exercise. During the initial 15 min after exercise, glycogen recovery in the GL trial was rapid (32.9 +/- 8.9 mmol. l(-1). h(-1)) compared with the Nor trial (15.9 +/- 6.9 mmol. l(-1). h(-1)). During the next 45 min, GL glycogen synthesis was not as rapid as in the Nor trial (0.9 +/- 2.5 mmol. l(-1). h(-1) for GL; 14.7 +/- 3.0 mmol. l(-1). h(-1) for Nor; P < or = 0.005) despite similar glucose 6-phosphate levels. During extended recovery (60-300 min), reduced GL recovery rates continued (1.3 +/- 0.5 mmol. l(-1). h(-1) for GL; 3.9 +/- 0.3 mmol. l(-1). h(-1) for Nor; P < or = 0.001). We conclude that glycogen recovery from heavy exercise is controlled primarily by the remaining postexercise glycogen concentration, with only a transient synthesis period when glycogen levels are not severely reduced. 相似文献
155.
Ananthan S Khare NK Saini SK Davis P Dersch CM Porreca F Rothman RB 《Bioorganic & medicinal chemistry》2003,11(18):4143-4154
A series of pyridomorphinans possessing an aryl (10a-s) or heteroaryl (11a-h) substituent at the 5'-position of the pyridine ring of 17-cyclopropylmethyl-4,5 alpha-epoxypyrido[2',3':6,7]morphinan was synthesized and evaluated for binding and functional activity at the opioid delta, mu, and kappa receptors. All of these pyridomorphinans bound with higher affinity at the delta site than at mu or kappa sites. The binding data on isomeric compounds revealed that there exists greater bulk tolerance for substituents placed at the o-position of the phenyl ring than at m- or p-positions. Among the ligands examined, the 2-chlorophenyl (10l), 2-nitrophenyl (10n), 2-pyridyl (11a), and 4-quinolinyl (11g) compounds bound to the delta receptor with subnanomolar affinity. Compound 10c with the p-tolyl substituent displayed the highest mu/delta selectivity (ratio=42) whereas compound 10l with the 2-chlorophenyl substituent displayed the highest kappa/delta selectivity (ratio=23). At 10 microM concentration, the in vitro functional activity determined using [(35)S]GTP-gamma-S binding assays showed that all of the compounds were antagonists devoid of any significant agonist activity at the delta, mu, and kappa receptors. Antagonist potency determinations of three selected ligands revealed that the p-tolyl compound 10c is a potent delta selective antagonist. In the [(35)S]GTP-gamma-S assays this compound had a functional antagonist K(i) value of 0.2, 4.52, and 7.62 nM at the delta, mu, and kappa receptors, respectively. In the smooth muscle assays 10c displayed delta antagonist potency with a K(e) value of 0.88 nM. As an antagonist, it was 70-fold more potent at the delta receptors in the MVD than at the mu receptors in the GPI. The in vitro delta antagonist profile of this pyridomorphinan 10c resembles that of the widely used delta selective antagonist ligand naltrindole. 相似文献
156.
157.
Bijay Mukherji Lenore Rothman Angelo Ucci Henry R. Casey Jr. Chi-Wei Lin Harry H. Miller 《Cancer immunology, immunotherapy : CII》1980,8(2-3):149-155
Summary In this study, we explored whether soluble tumor-cell surface-associated antigens (TAA) might be derived from autochthonous as well as allogeneic sources as immunogens for active specific immunotherapy. Using two popular cell membrane-bound antigen extraction techniques (3 M KCl and isotonic-hypotonic NaCl), we examined the immunogenic potential of such TAA and the specificity of immunologic host reactivity through a delayed-type cutaneous hypersensitivity reaction (DTH) as a guideline for their immunogenic potential in a human malignant melanoma model system. We found that either extraction technique could provide soluble TAA from both autochthonous and allogeneic sources capable of eliciting DTH. While evidence of positive DTH with autochthonous TAA reaffirms the immunogenicity of such TAA, the specificity of host reactivity against TAA derived from allogeneic sources is extremely difficult to establish, even with TAA partially purified by column chromatography in Sephadex G-200. Patients exhibited reactivity to other TAA derived from tumors of different histologies and often to more than one component isolated by column chromatography. Furthermore, when a group of melanoma patients was tested against a panel of melanoma antigens in any random combination, DTH to allogeneic TAA was seen in an unpredictable order and with inconsistent frequency. We conclude, therefore, that while autochthonous antigen immunizations may be justified, more careful studies will be necessary to define the antigenic profile of a given tumor (individual specificity vs shared specificity), establish specificity of alloantigens, and devise suitable methods for testing immunologic specificity for alloantigens, before rational immunotherapy with allogeneic tumor antigens will be feasible. 相似文献
158.
Multiple cytosolic components promote intra-Golgi protein transport. Resolution of a protein acting at a late stage, prior to membrane fusion 总被引:12,自引:0,他引:12
Cytosolic components are required to produce the "primed donor" and to consume the "dilution-resistant" intermediates of the intercompartmental protein transport pathway as elucidated in a cell-free system (Balch, W. E., Glick, B. S., and Rothman, J. E. (1984) Cell 39, 525-536, and Wattenberg, B. W., Balch, W. E., and Rothman, J. E. (1986) J. Biol. Chem. 261, 2202-2207). Widely different levels of crude cytosol are required for each of these steps, suggesting that different cytosolic components might mediate each step. Here, we fractionate cytosol and demonstrate that there are multiple transport-active components. Furthermore, we report the development of stage-specific functional assays which reveal that a distinct soluble component is required in the consumption of the dilution-resistant intermediate. This component, of about 25 kilodaltons in its apparent native molecular mass, is derived from calf brain cytosol. While this component mediates the consumption of the dilution-resistant intermediate, it is inactive in the priming stage. This stage-specific component seems likely to be involved in the processing of transport vesicles after the attachment of those vesicles to the target membranes. 相似文献
159.
Rates and patterns of evolution in partial sequences of five mitochondrial
genes (cytochrome b, ATPase 6, NADH dehydrogenase subunit 5, tRNA(Glu), and
the control region) were compared among taxa in the passerine bird genera
Fringilla and Carduelis. Rates of divergence do not vary significantly
among genes, even in comparisons with the control region. Rate variation
among lineages is significant only for the control region and NADH
dehydrogenase subunit 5, and patterns of variation are consistent with the
expectations of neutral theory. Base composition is biased in all genes but
is stationary among lineages, and there is evidence for directional
mutation pressure only in the control region. Despite these similarities,
patterns of substitution differ among genes, consistent with alternative
regimes of selective constraint. Rates of nonsynonymous substitution are
higher in NADH dehydrogenase subunit 5 than in other protein-coding genes,
and transitions exist in elevated proportions relative to transversions.
Transitions appear to accumulate linearly with time in tRNA(Glu), and
despite exhibiting the highest overall rate of divergence among species,
there are no transversional changes in this gene. Finally, for resolving
phylogenetic relationships among Fringilla taxa, the combined
protein-coding data are broadly similar to those of the control region in
terms of phylogenetic informativeness and statistical support.
相似文献
160.
Neurochemical Research - 相似文献