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  • 1
    ISSN: 1432-1998
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We report a healthy, asymptomatic 15-year-old girl with a meandering right pulmonary vein draining to the left atrium. A meandering pulmonary vein may or may not be associated with the scimitar syndrome. The differential diagnosis with the scimitar syndrome and other forms of scimitar variants is discussed.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Neutralizing antibodies (Nab) are a principal component of an effective human immune response to many pathogens, yet their role in HIV-1 infection is unclear. To gain a better understanding of this role, we examined plasma from patients with acute HIV infection. Here we report the detection of ...
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  • 3
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Nature 422, 307–312 (2003). In the seventh panel of Fig. 2 of this Letter, the V5 sequence of clone 391-3 appeared incorrectly as: SEKDQTEIFRP. It should read: SKDNQTEIFRP. In addition, there should be no yellow shading (indicating a ...
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  • 4
    ISSN: 1573-5176
    Keywords: toxicity evaluation ; reproductive toxicology ; single cellproteins ; Spirulina
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Spirulina maxima, provided by Sosa Texcoco Company (México City), was administered to mice of both sexes in a fertility study, at concentrations of 0, 10, 20 and 30% incorporated into the diet. Males were fed for nine weeks while females, for two weeks, and feeding continued during the mating period and gestation. On the other hand, in a peri- and postnatal study, the alga was given only to females at the same concentrations from day 15 of gestation until day 21 post-partum. Treatments were not associated with any adverse effect on reproductive performance, pregnancy rate, number of corpora lutea, resorptions or number of live or dead fetuses. There was no increase in the number of abnormal pups at caesarean section. Length of gestation, parturition status, and litter values were unaffected by treatment. However, there was a statistically significant reduction in bodyweight and survival rate on postnatal days 0–4 at the high dose group in the peri- and postnatal study. The reproductive performance of F1 generation was normal in all groups. We conclude that S. maxima is not toxic to reproduction.
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  • 5
    Keywords: CELL ; Germany ; KINASE ; PATHWAY ; PATHWAYS ; SYSTEMS ; SITE ; SITES ; DISTINCT ; PROTEIN ; TIME ; ACTIVATION ; RESPONSES ; MECHANISM ; BINDING ; PHOSPHORYLATION ; TARGET ; PATTERNS ; SIGNAL-TRANSDUCTION ; ULTRASENSITIVITY ; AFFINITY ; signaling ; SINGLE ; INCREASE ; PHOSPHORYLATION SITES ; ENZYME ; analysis ; PHOSPHATASE ; PREDICT ; INCREASES ; DUAL PHOSPHORYLATION ; INTERCONVERTIBLE ENZYME CASCADES ; METABOLIC-REGULATION ; MULTIPLE PHOSPHORYLATION ; multisite phosphorylation ; order of phosphate processing ; stimulus-response relationship ; TRANSCRIPTION FACTOR NFAT1 ; transition time
    Abstract: Multisite protein phosphorylation is a common regulatory mechanism in cell signaling, and dramatically increases the possibilities for protein-protein interactions, conformational regulation, and phosphorylation pathways. However, there is at present no comprehensive picture of how these factors shape the response of a protein's phosphorylation state to changes in kinase and phosphatase activities. Here we provide a mathematical theory for the regulation of multisite protein phosphorylation based on the mechanistic description of elementary binding and catalytic steps. Explicit solutions for the steady-state response curves and characteristic (de)phosphorylation times have been obtained in special cases. The order of phosphate processing and the characteristics of protein-protein interactions turn out to be of overriding importance for both sensitivity and speed of response. Random phosphate processing gives rise to shallow response curves, favoring intermediate phosphorylation states of the target, and rapid kinetics. Sequential processing is characterized by steeper response curves and slower kinetics. We show systematically how qualitative differences in target phosphorylation - including graded, switch-like and bistable responses - are determined by the relative concentrations of enzyme and target as well as the enzyme-target affinities. In addition to collective effects of several phosphorylation sites, our analysis predicts that distinct phosphorylation patterns can be finely tuned by a single kinase. Taken together, this study suggests a versatile regulation of protein activation by the combined effect of structural, kinetic and thermodynamic aspects of multisite phosphorylation
    Type of Publication: Journal article published
    PubMed ID: 17257173
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  • 6
    Keywords: CANCER ; LUNG ; PHASE-I ; lung cancer ; LUNG-CANCER ; EPIDEMIOLOGY ; CARCINOGENESIS ; ASSOCIATION ; polymorphism ; SUSCEPTIBILITY ; METABOLITES ; PROMOTER ; AGE ; genetics ; REDUCED RISK ; smoking ; DATABASE ; REGION ; heredity ; DEFICIENCY ; VARIANT ; CARCINOGEN ; METAANALYSIS ; INTERVAL ; ENZYME ; analysis ; PHASE ; MISSENSE MUTATION ; GENOTYPE ; USA ; female ; Male ; odds ratio ; E ; Phase I ; MPO ; cooperative studies ; metabolic gene polymorphisms ; ACID RESPONSE ELEMENT ; DNA ADDUCT LEVELS ; HUMAN SKIN FIBROBLASTS ; HYPOCHLOROUS ACID
    Abstract: Myeloperoxidase is a phase I metabolic enzyme that converts the metabolites of benzo[a]pyrene from tobacco smoke into highly reactive epoxides. A polymorphism in the promoter region of myeloperoxidase (463G -〉 A) has been found to be inversely associated with lung cancer; differences in the association with age and gender have been suggested. We conducted a pooled analysis of individual data from 10 studies (3688 cases and 3874 controls) from the Genetic Susceptibility to Environmental Carcinogens database. The odds ratio for lung cancer was 0.88 (95% confidence interval: 0.80-0.97) for the AG variant of myeloperoxidase G-463A polymorphism, and 0.71 (95% confidence interval: 0.57-0.88) for the AA variant after adjusting for smoking, age, gender, and ethnicity. The inverse association between lung cancer and myeloperoxidase G-463A polymorphism was equally found in males and females (odds ratio for the AA genotype 0.73 [95% confidence interval: 0.56-0.96] and 0.67 [95% confidence interval: 0.46-0.98], respectively), without differences in the association according to age in the two genders. The myeloperoxicase G-463A polymorphism was significantly protective in "ever" smokers but not in "never" smokers. Myeloperoxidase is a key enzyme in tobacco-induced carcinogenesis
    Type of Publication: Journal article published
    PubMed ID: 17304047
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  • 7
    Keywords: CANCER ; Germany ; POPULATION ; RISK ; GENES ; PROTEIN ; PROTEINS ; TRANSDUCTION ; PATIENT ; ACTIVATION ; MECHANISM ; IMPACT ; CARCINOGENESIS ; signal transduction ; ASSOCIATION ; polymorphism ; POLYMORPHISMS ; SUSCEPTIBILITY ; BREAST ; breast cancer ; BREAST-CANCER ; MUTATION ; SIGNAL-TRANSDUCTION ; cancer risk ; ONCOLOGY ; RE ; BRCA2 ; INCREASE ; analysis ; TESTS ; USA ; BINDING DOMAIN ; CANCER-RISK ; EPITHELIAL OVARIAN-CANCER ; KINASE-ANCHORING PROTEINS
    Abstract: Data from several studies have suggested that polymorphisms in A-kinase anchoring proteins (AKAPs), which are key components of signal transduction, contribute to carcinogenesis. To evaluate the impact of AKAP variants on breast cancer risk, we genotyped six nonsynonymous sing le-nucleotide polymorphisms that were predicted to be deleterious and found two (M4631, 1389G〉T and N2792S, 8375A〉G) to be associated with an allele dose-dependent increase in risk of familial breast cancer in a German population. We extended the analysis of AKAP9 M4631, which is in strong linkage disequilibrium with AKAP9 N2792S, to 9523 breast cancer patients and 13770 healthy control subjects from seven independent European and Australian breast cancer studies. All statistical tests were two-sided. The collaborative analysis confirmed the association of M4631 with increased breast cancer risk. Among all breast cancer patients, the combined adjusted odds ratio (OR) of breast cancer for individuals homozygous for the rare allele TT (frequency = 0.19) compared with GG homozygotes was 1.17 (95% confidence interval [CL] = 1.08 to 1.27, P =.0003), and the OR for TT homozygotes plus GT heterozygotes compared with GG homozygotes was 1.10 (95% Cl = 1.04 to 1.17, P=.001). Among the combined subset of 2795 familial breast cancer patients, the respective ORs were 1.27 (95% Cl = 1.12 to 1.45, P =.0003) and 1.16 (95% Cl = 1.06 to 1.27, P =.001)
    Type of Publication: Journal article published
    PubMed ID: 18334708
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  • 8
    Keywords: EXPRESSION ; Germany ; KINASE ; MODEL ; MODELS ; ENZYMES ; GENE ; GENE-EXPRESSION ; PROTEIN ; PROTEINS ; METABOLISM ; TRANSDUCTION ; RESPONSES ; MECHANISM ; mechanisms ; PHOSPHORYLATION ; signal transduction ; SIGNAL ; TARGET ; gene expression ; NUMBER ; SIGNAL-TRANSDUCTION ; PARAMETERS ; CALCIUM ; sensitivity ; specificity ; PROTEIN-PHOSPHORYLATION ; signaling ; ORDER ; molecular ; RE ; ENZYME ; USA ; SIGNALS ; modeling ; SHAPE ; CAM KINASE-II ; COMPLEX CA2+ SIGNALS ; CYTOSOLIC CALCIUM ; GLYCOGEN-PHOSPHORYLASE ; MATHEMATICAL-ANALYSIS ; MINIMAL MODEL ; PHOSPHOLIPASE C-DELTA-1 ; SPIKE FREQUENCY
    Abstract: Experimental studies have demonstrated that Ca2+-regulated proteins are sensitive to the frequency of Ca2+ oscillations, and several mathematical models for specific proteins have provided insight into the mechanisms involved. Because of the large number of Ca2+-regulated proteins in signal transduction, metabolism and gene expression, it is desirable to establish in general terms which molecular properties shape the response to oscillatory Ca2+ signals. Here we address this question by analyzing in detail a model of a prototypical Ca2+-decoding module, consisting of a target protein whose activity is controlled by a Ca2+-activated kinase and the counteracting phosphatase. We show that this module can decode the frequency of Ca2+ oscillations, at constant average Ca2+ signal, provided that the Ca2+ spikes are narrow and the oscillation frequency is sufficiently low-of the order of the phosphatase rate constant or below. Moreover, Ca2+ oscillations activate the target more efficiently than a constant signal when Ca2+ is bound cooperatively and with low affinity. Thus, the rate constants and the Ca2+ affinities of the target-modifying enzymes can be tuned in such a way that the module responds optimally to Ca2+ spikes of a certain amplitude and frequency. Frequency sensitivity is further enhanced when the limited duration of the external stimulus driving Ca2+ signaling is accounted for. Thus, our study identifies molecular parameters that may be involved in establishing the specificity of cellular responses downstream of Ca2+ oscillations
    Type of Publication: Journal article published
    PubMed ID: 17921221
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  • 9
    Keywords: CELL ; Germany ; MODEL ; CRASSA ; GENE ; PROTEIN ; transcription ; ACCUMULATION ; TIME ; COMPLEX ; COMPLEXES ; TRANSCRIPTION FACTOR ; BIOLOGY ; CYCLE ; PHOSPHORYLATION ; FREQUENCIES ; Drosophila ; genetics ; DISPLAY ; LOCALIZATION ; NUCLEUS ; KINETICS ; REGULATOR ; PROTEIN-PHOSPHORYLATION ; SCALE ; LEVEL ; USA ; EXPORT ; STEADY-STATE ; CIRCADIAN CLOCK ; Genetic ; Developmental ; TRANSCRIPTION-FACTOR ; ENTRAINMENT ; EPSILON ; FRQ ; GENE-FREQUENCY ; INTERLOCKED FEEDBACK LOOPS ; OUTPUT ; RHYTHMS ; subcellular shuttling
    Abstract: The Neurospora clock protein FREQUENCY (FRQ) is an essential regulator of the circadian transcription factor WHITE COLLAR COMPLEX (WCC). In the course of a circadian period, the subcellular distribution of FRQ shifts from mainly nuclear to mainly cytosolic. This shift is crucial for coordinating the negative and positive limbs of the clock. We show that the subcellular redistribution of FRQ on a circadian time scale is governed by rapid, noncircadian cycles of nuclear import and export. The rate of nuclear import of newly synthesized FRQ is progressively reduced in a phosphorylation-dependent manner, leading to an increase in the steady-state level of cytoplasmic FRQ. The long-period frq(7) mutant displays reduced kinetics of FRQ(7) protein phosphorylation and a prolonged accumulation in the nucleus. We present a mathematical model that describes the cytoplasmic accumulation of wild-type and mutant FRQ on a circadian time scale on the basis of frequency-modulated rapid nucleocytoplasmic shuttling cycles
    Type of Publication: Journal article published
    PubMed ID: 19759264
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  • 10
    Keywords: Germany ; MODEL ; MODELS ; SITES ; PROTEIN ; MECHANISM ; mechanisms ; BIOLOGY ; PHOSPHORYLATION ; DNA-REPLICATION ; KINETICS ; sensitivity ; specificity ; ULTRASENSITIVITY ; TYROSINE PHOSPHORYLATION ; PROTEIN-PHOSPHORYLATION ; molecular biology ; review ; regulation ; SRC FAMILY KINASES ; PHOSPHORYLATION SITES ; PROCESSIVITY ; USA ; MULTIPLE PHOSPHORYLATION ; TRANSCRIPTION FACTOR NFAT1 ; WELL ; mathematical models ; DROSOPHILA PERIOD PROTEIN ; DUAL-KINASE MECHANISM ; enzyme processivity ; kinetic proofreading ; order of phospho-site processing ; PROCESSIVE PHOSPHORYLATION ; SIGNAL-TRANSDUCTION CASCADES ; SPLICING FACTOR ASF/SF2
    Abstract: Multisite phosphorylation is an important mechanism for fine-tuned regulation of protein function. Mathematical models developed over recent years have contributed to elucidation of the functional consequences of a variety of molecular mechanisms involved in processing of the phosphorylation sites. Here we review the results of such models, together with salient experimental findings on multisite protein phosphorylation. We discuss how molecular mechanisms that can be distinguished with respect to the order and processivity of phosphorylation, as well as other factors, regulate changes in the sensitivity and kinetics of the response, the synchronization of molecular events, signalling specificity, and other functional implications
    Type of Publication: Journal article published
    PubMed ID: 19438722
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