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Publication
Journal: Science
December/5/1996
Abstract
The MDM2 oncoprotein is a cellular inhibitor of the p53 tumor suppressor in that it can bind the transactivation domain of p53 and downregulate its ability to activate transcription. In certain cancers, MDM2 amplification is a common event and contributes to the inactivation of p53. The crystal structure of the 109-residue amino-terminal domain of MDM2 bound to a 15-residue transactivation domain peptide of p53 revealed that MDM2 has a deep hydrophobic cleft on which the p53 peptide binds as an amphipathic alpha helix. The interface relies on the steric complementarity between the MDM2 cleft and the hydrophobic face of the p53 alpha helix and, in particular, on a triad of p53 amino acids-Phe19, Trp23, and Leu26-which insert deep into the MDM2 cleft. These same p53 residues are also involved in transactivation, supporting the hypothesis that MDM2 inactivates p53 by concealing its transactivation domain. The structure also suggests that the amphipathic alpha helix may be a common structural motif in the binding of a diverse family of transactivation factors to the TATA-binding protein-associated factors.
Publication
Journal: Journal of Cognitive Neuroscience
August/22/2013
Abstract
Nine previous positron emission tomography (PET) studies of human visual information processing were reanalyzed to determine the consistency across experiments of blood flow decreases during active tasks relative to passive viewing of the same stimulus array. Areas showing consistent decreases during active tasks included posterior cingulate/precuneous (Brodmann area, BA 31/7), left (BAS 40 and 39/19) and right (BA 40) inferior parietal cortex, left dorsolateral frontal cortex (BA S), left lateral inferior frontal cortex (BA 10/47), left inferior temporal gyrus @A 20), a strip of medial frontal regions running along a dorsal-ventral axis (BAs 8, 9, 10, and 32), and the right amygdala. Experiments involving language-related processes tended to show larger decreases than nonlanguage experiments. This trend mainly reflected blood flow increases at certain areas in the passive conditions of the language experiments (relative to a fixation control in which no task stimulus was present) and slight blood flow decreases in the passive conditions of the nonlanguage experiments. When the active tasks were referenced to the fixation condition, the overall size of blood flow decreases in language and nonlanguage tasks were the same, but differences were found across cortical areas. Decreases were more pronounced in the posterior cingulate/precuneous (BAS 31/7) and right inferior parietal cortex (BA 40) during language-related tasks and more pronounced in left inferior frontal cortex (BA 10/47) during nonlanguage tasks. Blood flow decreases did not generally show significant differences across the active task states within an experiment, but a verb-generation task produced larger decreases than a read task in right and left inferior parietal lobe (BA 40) and the posterior cingulate/precuneous (BA 31/7), while the read task produced larger decreases in left lateral inferior frontal cortex (BA 10/47). These effects mirrored those found between experiments in the language-nonlanguage comparison. Consistent active minus passive decreases may reflect decreased activity caused by active task processes that generalize over tasks or increased activity caused by passive task processes that are suspended during the active tasks. Increased activity during the passive condition might reflect ongoing processes, such as unconstrained verbally mediated thoughts and monitoring of the external environment, body, and emotional state.
Publication
Journal: Health Psychology
December/1/2008
Abstract
OBJECTIVE
Without standardized definitions of the techniques included in behavior change interventions, it is difficult to faithfully replicate effective interventions and challenging to identify techniques contributing to effectiveness across interventions. This research aimed to develop and test a theory-linked taxonomy of generally applicable behavior change techniques (BCTs).
METHODS
Twenty-six BCTs were defined. Two psychologists used a 5-page coding manual to independently judge the presence or absence of each technique in published intervention descriptions and in intervention manuals.
RESULTS
Three systematic reviews yielded 195 published descriptions. Across 78 reliability tests (i.e., 26 techniques applied to 3 reviews), the average kappa per technique was 0.79, with 93% of judgments being agreements. Interventions were found to vary widely in the range and type of techniques used, even when targeting the same behavior among similar participants. The average agreement for intervention manuals was 85%, and a comparison of BCTs identified in 13 manuals and 13 published articles describing the same interventions generated a technique correspondence rate of 74%, with most mismatches (73%) arising from identification of a technique in the manual but not in the article.
CONCLUSIONS
These findings demonstrate the feasibility of developing standardized definitions of BCTs included in behavioral interventions and highlight problematic variability in the reporting of intervention content.
Publication
Journal: Cancer Cell
November/19/2007
Abstract
A large-scale RNA interference screen to discover genes involved in trastuzumab resistance in breast cancer identified only PTEN as a modulator of drug sensitivity. Oncogenic mutants of PIK3CA (activator of the same pathway and frequently mutated in breast cancer) also conferred resistance to trastuzumab in cell culture. In a cohort of 55 breast cancer patients, activation of the PI3K pathway, as judged by the presence of oncogenic PIK3CA mutations or low PTEN expression, was associated with poor prognosis after trastuzumab therapy, and the combined analysis of PTEN and PIK3CA identified twice as many patients at increased risk for progression compared to PTEN alone. Thus, assessment of PI3K pathway activation may provide a biomarker to identify patients unlikely to respond to trastuzumab-based therapy.
Publication
Journal: NeuroImage
October/25/2009
Abstract
The fine spatial scales of the structures in the human brain represent an enormous challenge to the successful integration of information from different images for both within- and between-subject analysis. While many algorithms to register image pairs from the same subject exist, visual inspection shows that their accuracy and robustness to be suspect, particularly when there are strong intensity gradients and/or only part of the brain is imaged. This paper introduces a new algorithm called Boundary-Based Registration, or BBR. The novelty of BBR is that it treats the two images very differently. The reference image must be of sufficient resolution and quality to extract surfaces that separate tissue types. The input image is then aligned to the reference by maximizing the intensity gradient across tissue boundaries. Several lower quality images can be aligned through their alignment with the reference. Visual inspection and fMRI results show that BBR is more accurate than correlation ratio or normalized mutual information and is considerably more robust to even strong intensity inhomogeneities. BBR also excels at aligning partial-brain images to whole-brain images, a domain in which existing registration algorithms frequently fail. Even in the limit of registering a single slice, we show the BBR results to be robust and accurate.
Publication
Journal: Sleep
September/8/2003
Abstract
In summary, although actigraphy is not as accurate as PSG for determining some sleep measurements, studies are in general agreement that actigraphy, with its ability to record continuously for long time periods, is more reliable than sleep logs which rely on the patients' recall of how many times they woke up or how long they slept during the night and is more reliable than observations which only capture short time periods. Actigraphy can provide information obtainable in no other practical way. It can also have a role in the medical care of patients with sleep disorders. However, it should not be held to the same expectations as polysomnography. Actigraphy is one-dimensional, whereas polysomnography comprises at least 3 distinct types of data (EEG, EOG, EMG), which jointly determine whether a person is asleep or awake. It is therefore doubtful whether actigraphic data will ever be informationally equivalent to the PSG, although progress on hardware and data processing software is continuously being made. Although the 1995 practice parameters paper determined that actigraphy was not appropriate for the diagnosis of sleep disorders, more recent studies suggest that for some disorders, actigraphy may be more practical than PSG. While actigraphy is still not appropriate for the diagnosis of sleep disordered breathing or of periodic limb movements in sleep, it is highly appropriate for examining the sleep variability (i.e., night-to-night variability) in patients with insomnia. Actigraphy is also appropriate for the assessment of and stability of treatment effects of anything from hypnotic drugs to light treatment to CPAP, particularly if assessments are done before and after the start of treatment. A recent independent review of the actigraphy literature by Sadeh and Acebo reached many of these same conclusions. Some of the research studies failed to find relationships between sleep measures and health-related symptoms. The interpretation of these data is also not clear-cut. Is it that the actigraph is not reliable enough to the access the relationship between sleep changes and quality of life measures, or, is it that, in fact, there is no relationship between sleep in that population and quality of life measures? Other studies of sleep disordered breathing, where actigraphy was not used and was not an outcome measure also failed to find any relationship with quality of life. Is it then the actigraph that is not reliable or that the associations just do not exist? The one area where actigraphy can be used for clinical diagnosis is in the evaluation of circadian rhythm disorders. Actigraphy has been shown to be very good for identifying rhythms. Results of actigraphic recordings correlate well with measurements of melatonin and of core body temperature rhythms. Activity records also show sleep disturbance when sleep is attempted at an unfavorable phase of the circadian cycle. Actigraphy therefore would be particularly good for aiding in the diagnosis of delayed or advanced sleep phase syndrome, non-24-hour-sleep syndrome and in the evaluation of sleep disturbances in shift workers. It must be remembered, however, that overt rest-activity rhythms are susceptible to various masking effects, so they may not always show the underlying rhythm of the endogenous circadian pacemaker. In conclusion, the latest set of research articles suggest that in the clinical setting, actigraphy is reliable for evaluating sleep patterns in patients with insomnia, for studying the effect of treatments designed to improve sleep, in the diagnosis of circadian rhythm disorders (including shift work), and in evaluating sleep in individuals who are less likely to tolerate PSG, such as infants and demented elderly. While actigraphy has been used in research studies for many years, up to now, methodological issues had not been systematically addressed in clinical research and practice. Those issues have now been addressed and actigraphy may now be reaching the maturity needed for application in the clinical arena.
Publication
Journal: New England Journal of Medicine
July/11/2013
Abstract
BACKGROUND
The treatment of relapsed chronic lymphocytic leukemia (CLL) has resulted in few durable remissions. Bruton's tyrosine kinase (BTK), an essential component of B-cell-receptor signaling, mediates interactions with the tumor microenvironment and promotes the survival and proliferation of CLL cells.
METHODS
We conducted a phase 1b-2 multicenter study to assess the safety, efficacy, pharmacokinetics, and pharmacodynamics of ibrutinib (PCI-32765), a first-in-class, oral covalent inhibitor of BTK designed for treatment of B-cell cancers, in patients with relapsed or refractory CLL or small lymphocytic lymphoma. A total of 85 patients, the majority of whom were considered to have high-risk disease, received ibrutinib orally once daily; 51 received 420 mg, and 34 received 840 mg.
RESULTS
Toxic effects were predominantly grade 1 or 2 and included transient diarrhea, fatigue, and upper respiratory tract infection; thus, patients could receive extended treatment with minimal hematologic toxic effects. The overall response rate was the same in the group that received 420 mg and the group that received 840 mg (71%), and an additional 20% and 15% of patients in the respective groups had a partial response with lymphocytosis. The response was independent of clinical and genomic risk factors present before treatment, including advanced-stage disease, the number of previous therapies, and the 17p13.1 deletion. At 26 months, the estimated progression-free survival rate was 75% and the rate of overall survival was 83%.
CONCLUSIONS
Ibrutinib was associated with a high frequency of durable remissions in patients with relapsed or refractory CLL and small lymphocytic lymphoma, including patients with high-risk genetic lesions. (Funded by Pharmacyclics and others; ClinicalTrials.gov number, NCT01105247.).
Publication
Journal: Psychological Methods
October/10/2006
Abstract
In meta-analysis, the usual way of assessing whether a set of single studies is homogeneous is by means of the Q test. However, the Q test only informs meta-analysts about the presence versus the absence of heterogeneity, but it does not report on the extent of such heterogeneity. Recently, the I(2) index has been proposed to quantify the degree of heterogeneity in a meta-analysis. In this article, the performances of the Q test and the confidence interval around the I(2) index are compared by means of a Monte Carlo simulation. The results show the utility of the I(2) index as a complement to the Q test, although it has the same problems of power with a small number of studies.
Publication
Journal: Systematic Biology
September/29/2002
Abstract
An approximately unbiased (AU) test that uses a newly devised multiscale bootstrap technique was developed for general hypothesis testing of regions in an attempt to reduce test bias. It was applied to maximum-likelihood tree selection for obtaining the confidence set of trees. The AU test is based on the theory of Efron et al. (Proc. Natl. Acad. Sci. USA 93:13429-13434; 1996), but the new method provides higher-order accuracy yet simpler implementation. The AU test, like the Shimodaira-Hasegawa (SH) test, adjusts the selection bias overlooked in the standard use of the bootstrap probability and Kishino-Hasegawa tests. The selection bias comes from comparing many trees at the same time and often leads to overconfidence in the wrong trees. The SH test, though safe to use, may exhibit another type of bias such that it appears conservative. Here I show that the AU test is less biased than other methods in typical cases of tree selection. These points are illustrated in a simulation study as well as in the analysis of mammalian mitochondrial protein sequences. The theoretical argument provides a simple formula that covers the bootstrap probability test, the Kishino-Hasegawa test, the AU test, and the Zharkikh-Li test. A practical suggestion is provided as to which test should be used under particular circumstances.
Publication
Journal: Proceedings of the National Academy of Sciences of the United States of America
January/4/2004
Abstract
Metal nanoshells are a class of nanoparticles with tunable optical resonances. In this article, an application of this technology to thermal ablative therapy for cancer is described. By tuning the nanoshells to strongly absorb light in the near infrared, where optical transmission through tissue is optimal, a distribution of nanoshells at depth in tissue can be used to deliver a therapeutic dose of heat by using moderately low exposures of extracorporeally applied near-infrared (NIR) light. Human breast carcinoma cells incubated with nanoshells in vitro were found to have undergone photothermally induced morbidity on exposure to NIR light (820 nm, 35 W/cm2), as determined by using a fluorescent viability stain. Cells without nanoshells displayed no loss in viability after the same periods and conditions of NIR illumination. Likewise, in vivo studies under magnetic resonance guidance revealed that exposure to low doses of NIR light (820 nm, 4 W/cm2) in solid tumors treated with metal nanoshells reached average maximum temperatures capable of inducing irreversible tissue damage (DeltaT = 37.4 +/- 6.6 degrees C) within 4-6 min. Controls treated without nanoshells demonstrated significantly lower average temperatures on exposure to NIR light (DeltaT < 10 degrees C). These findings demonstrated good correlation with histological findings. Tissues heated above the thermal damage threshold displayed coagulation, cell shrinkage, and loss of nuclear staining, which are indicators of irreversible thermal damage. Control tissues appeared undamaged.
Publication
Journal: New England Journal of Medicine
June/21/2000
Abstract
BACKGROUND
In the hierarchy of research designs, the results of randomized, controlled trials are considered to be evidence of the highest grade, whereas observational studies are viewed as having less validity because they reportedly overestimate treatment effects. We used published meta-analyses to identify randomized clinical trials and observational studies that examined the same clinical topics. We then compared the results of the original reports according to the type of research design.
METHODS
A search of the Medline data base for articles published in five major medical journals from 1991 to 1995 identified meta-analyses of randomized, controlled trials and meta-analyses of either cohort or case-control studies that assessed the same intervention. For each of five topics, summary estimates and 95 percent confidence intervals were calculated on the basis of data from the individual randomized, controlled trials and the individual observational studies.
RESULTS
For the five clinical topics and 99 reports evaluated, the average results of the observational studies were remarkably similar to those of the randomized, controlled trials. For example, analysis of 13 randomized, controlled trials of the effectiveness of bacille Calmette-Guérin vaccine in preventing active tuberculosis yielded a relative risk of 0.49 (95 percent confidence interval, 0.34 to 0.70) among vaccinated patients, as compared with an odds ratio of 0.50 (95 percent confidence interval, 0.39 to 0.65) from 10 case-control studies. In addition, the range of the point estimates for the effect of vaccination was wider for the randomized, controlled trials (0.20 to 1.56) than for the observational studies (0.17 to 0.84).
CONCLUSIONS
The results of well-designed observational studies (with either a cohort or a case-control design) do not systematically overestimate the magnitude of the effects of treatment as compared with those in randomized, controlled trials on the same topic.
Publication
Journal: Journal of Experimental Psychology: General
June/1/1988
Abstract
This article has two purposes. The first is to describe four theoretical models of yes-no recognition memory and present their associated measures of discrimination and response bias. These models are then applied to a set of data from normal subjects to determine which pairs of discrimination and bias indices show independence between discrimination and bias. The following models demonstrated independence: a two-high-threshold model, a signal detection model with normal distributions using d' and C (rather than beta), and a signal detection model with logistic distributions and a bias measure analogous to C. C is defined as the distance of criterion from the intersection of the two underlying distributions. The second purpose is to use the indices from the acceptable models to characterize recognition memory deficits in dementia and amnesia. Young normal subjects, Alzheimer's disease patients, and parkinsonian dementia patients were tested with picture recognition tasks with repeated study-test trials. Huntington's disease patients, mixed etiology amnesics, and age-matched normals were tested by Butters, Wolfe, Martone, Granholm, and Cermak (1985) using the same paradigm with word stimuli. Demented and amnesic patients produced distinctly different patterns of abnormal memory performance. Both groups of demented patients showed poor discrimination and abnormally liberal response bias for words (Huntington's disease) and pictures (Alzheimer's disease and parkinsonian dementia), whereas the amnesic patients showed the worst discrimination but normal response bias for words. Although both signal detection theory and two-high-threshold discrimination parameters showed identical results, the bias measure from the two-high-threshold model was more sensitive to change than the bias measure (C) from signal detection theory. Three major points are emphasized. First, any index of recognition memory performance assumes an underlying model. Second, even acceptable models can lead to different conclusions about patterns of learning and forgetting. Third, efforts to characterize and ameliorate abnormal memory should address both discrimination and bias deficits.
Publication
Journal: Annual Review of Microbiology
January/20/2003
Abstract
Prokaryotic biofilms that predominate in a diverse range of ecosystems are often composed of highly structured multispecies communities. Within these communities metabolic activities are integrated, and developmental sequences, not unlike those of multicellular organisms, can be detected. These structural adaptations and interrelationships are made possible by the expression of sets of genes that result in phenotypes that differ profoundly from those of planktonically grown cells of the same species. Molecular and microscopic evidence suggest the existence of a succession of de facto biofilm phenotypes. We submit that complex cell-cell interactions within prokaryotic communities are an ancient characteristic, the development of which was facilitated by the localization of cells at surfaces. In addition to spatial localization, surfaces may have provided the protective niche in which attached cells could create a localized homeostatic environment. In a holistic sense both biofilm and planktonic phenotypes may be viewed as integrated components of prokaryote life.
Publication
Journal: British Medical Journal
June/24/2009
Abstract
OBJECTIVE
To determine the quantitative efficacy of different classes of blood pressure lowering drugs in preventing coronary heart disease (CHD) and stroke, and who should receive treatment.
METHODS
Meta-analysis. Data source Medline (1966-2007).
METHODS
Randomised trials of blood pressure lowering drugs recording CHD events and strokes. 108 trials studied differences in blood pressure between study drug and placebo (or control group not receiving the study drug) ("blood pressure difference trials"), and 46 trials compared drugs ("drug comparison trials"). Seven trials with three randomised groups fell into both categories. The results were interpreted in the context of those expected from the largest published meta-analysis of cohort studies, totalling 958 000 people.
METHODS
464 000 people defined into three mutually exclusive categories: participants with no history of vascular disease, a history of CHD, or a history of stroke.
RESULTS
In the blood pressure difference trials beta blockers had a special effect over and above that due to blood pressure reduction in preventing recurrent CHD events in people with a history of CHD: risk reduction 29% (95% confidence interval 22% to 34%) compared with 15% (11% to 19%) in trials of other drugs. The extra effect was limited to a few years after myocardial infarction, with a risk reduction of 31% compared with 13% in people with CHD with no recent infarct (P=0.04). In the other blood pressure difference trials (excluding CHD events in trials of beta blockers in people with CHD), there was a 22% reduction in CHD events (17% to 27%) and a 41% (33% to 48%) reduction in stroke for a blood pressure reduction of 10 mm Hg systolic or 5 mm Hg diastolic, similar to the reductions of 25% (CHD) and 36% (stroke) expected for the same difference in blood pressure from the cohort study meta-analysis, indicating that the benefit is explained by blood pressure reduction itself. The five main classes of blood pressure lowering drugs (thiazides, beta blockers, angiotensin converting enzyme inhibitors, angiotensin receptor blockers, and calcium channel blockers) were similarly effective (within a few percentage points) in preventing CHD events and strokes, with the exception that calcium channel blockers had a greater preventive effect on stroke (relative risk 0.92, 95% confidence interval 0.85 to 0.98). The percentage reductions in CHD events and stroke were similar in people with and without cardiovascular disease and regardless of blood pressure before treatment (down to 110 mm Hg systolic and 70 mm Hg diastolic). Combining our results with those from two other studies (the meta-analyses of blood pressure cohort studies and of trials determining the blood pressure lowering effects of drugs according to dose) showed that in people aged 60-69 with a diastolic blood pressure before treatment of 90 mm Hg, three drugs at half standard dose in combination reduced the risk of CHD by an estimated 46% and of stroke by 62%; one drug at standard dose had about half this effect. The present meta-analysis also showed that drugs other than calcium channel blockers (with the exception of non-cardioselective beta blockers) reduced the incidence of heart failure by 24% (19% to 28%) and calcium channel blockers by 19% (6% to 31%).
CONCLUSIONS
With the exception of the extra protective effect of beta blockers given shortly after a myocardial infarction and the minor additional effect of calcium channel blockers in preventing stroke, all the classes of blood pressure lowering drugs have a similar effect in reducing CHD events and stroke for a given reduction in blood pressure so excluding material pleiotropic effects. The proportional reduction in cardiovascular disease events was the same or similar regardless of pretreatment blood pressure and the presence or absence of existing cardiovascular disease. Guidelines on the use of blood pressure lowering drugs can be simplified so that drugs are offered to people with all levels of blood pressure. Our results indicate the importance of lowering blood pressure in everyone over a certain age, rather than measuring it in everyone and treating it in some.
Publication
Journal: Molecular Cell
August/30/1998
Abstract
Progression through the eukaryotic cell cycle is known to be both regulated and accompanied by periodic fluctuation in the expression levels of numerous genes. We report here the genome-wide characterization of mRNA transcript levels during the cell cycle of the budding yeast S. cerevisiae. Cell cycle-dependent periodicity was found for 416 of the 6220 monitored transcripts. More than 25% of the 416 genes were found directly adjacent to other genes in the genome that displayed induction in the same cell cycle phase, suggesting a mechanism for local chromosomal organization in global mRNA regulation. More than 60% of the characterized genes that displayed mRNA fluctuation have already been implicated in cell cycle period-specific biological roles. Because more than 20% of human proteins display significant homology to yeast proteins, these results also link a range of human genes to cell cycle period-specific biological functions.
Publication
Journal: New England Journal of Medicine
October/21/2013
Abstract
BACKGROUND
Whole-exome sequencing is a diagnostic approach for the identification of molecular defects in patients with suspected genetic disorders.
METHODS
We developed technical, bioinformatic, interpretive, and validation pipelines for whole-exome sequencing in a certified clinical laboratory to identify sequence variants underlying disease phenotypes in patients.
RESULTS
We present data on the first 250 probands for whom referring physicians ordered whole-exome sequencing. Patients presented with a range of phenotypes suggesting potential genetic causes. Approximately 80% were children with neurologic phenotypes. Insurance coverage was similar to that for established genetic tests. We identified 86 mutated alleles that were highly likely to be causative in 62 of the 250 patients, achieving a 25% molecular diagnostic rate (95% confidence interval, 20 to 31). Among the 62 patients, 33 had autosomal dominant disease, 16 had autosomal recessive disease, and 9 had X-linked disease. A total of 4 probands received two nonoverlapping molecular diagnoses, which potentially challenged the clinical diagnosis that had been made on the basis of history and physical examination. A total of 83% of the autosomal dominant mutant alleles and 40% of the X-linked mutant alleles occurred de novo. Recurrent clinical phenotypes occurred in patients with mutations that were highly likely to be causative in the same genes and in different genes responsible for genetically heterogeneous disorders.
CONCLUSIONS
Whole-exome sequencing identified the underlying genetic defect in 25% of consecutive patients referred for evaluation of a possible genetic condition. (Funded by the National Human Genome Research Institute.).
Publication
Journal: Annual Review of Biochemistry
October/10/1989
Abstract
Four major serine/threonine-specific protein phosphatase catalytic subunits are present in the cytoplasm of animal cells. Three of these enzymes, PP-1, PP-2A, and PP-2B, are members of the same gene family, while PP-2C appears to be distinct. PP-1, PP-2A, and PP-2B are complexed to other subunits in vivo, whereas PP-2C has only been isolated as a monomeric protein. PP-1, PP-2A, and PP-2C have broad and overlapping specificities in vitro, and account for virtually all measurable activity in tissue extracts toward a variety of phosphoproteins that regulate metabolism, muscle contractility, and other processes. Their precise functions in vivo are unknown, although important clues to the physiological roles of PP-1 and PP-2A are provided by the effects of okadaic acid and by the subcellular localization of PP-1. The active forms of PP-1 are largely particulate, and their association with subcellular structures is mediated by "targetting subunits" that direct PP-1 to particular locations, enhance its activity toward certain substrates, and confer important regulatory properties upon it. This concept is best established for the glycogen-bound enzymes in skeletal muscle and liver (PP-1G) and the myofibrillar form (PP-1M) in skeletal muscle. The activities of PP-1 and PP-2B are controlled by the second messengers cyclic AMP and calcium. The activity of PP-2B is dependent on calcium and calmodulin, while PP-1 is controlled in a variety of ways that depend on the form of the enzyme and the tissue. PP-1 can be inhibited by cyclic AMP in a variety of cells through the A-kinase-catalyzed phosphorylation of inhibitor-1 and its isoforms. Phosphorylation of the glycogen-binding subunit of PP-1G by A-kinase promotes translocation of the catalytic subunit from glycogen particles to cytosol in skeletal muscle, inhibiting the dephosphorylation of glycogen-metabolizing enzymes. Allosteric inhibition of hepatic PP-1G by phosphorylase a occurs in response to signals that elevate cyclic AMP or calcium, and prevents the activation of glycogen synthase in liver. PP-1 can also be activated indirectly by calcium through the ability of PP-2B to dephosphorylate inhibitor-1. This control mechanism may operate in dopaminoceptive neurones of the brain and other cells. The inactive cytosolic form of PP-1 (PP-1I) can be activated in vitro through the glycogen synthase kinase-3-catalyzed phosphorylation of its inhibitory subunit (inhibitor-2), but the physiological significance is unclear.(ABSTRACT TRUNCATED AT 400 WORDS)
Authors
Publication
Journal: Journal of Clinical Oncology
May/26/1999
Abstract
OBJECTIVE
Immunohistochemistry (IHC) is a newer technique for assessing the estrogen receptor (ER) status of breast cancers, with the potential to overcome many of the shortcomings associated with the traditional ligand-binding assay (LBA). The purpose of this study was to evaluate the ability of ER status determination by IHC, compared with LBA, to predict clinical outcome-especially response to adjuvant endocrine therapy-in a large number of patients with long-term clinical follow-up.
METHODS
ER status was evaluated in 1,982 primary breast cancers by IHC on formalin-fixed paraffin-embedded tissue sections, using antibody 6F11 and standard methodology. Slides were scored on a scale representing the estimated proportion and intensity of positive-staining tumor cells (range, 0 to 8). Results were compared with ER values obtained by the LBA in the same tumors and to clinical outcome.
RESULTS
An IHC score of greater than 2 (corresponding to as few as 1% to 10% weakly positive cells) was used to define ER positivity on the basis of a univariate cut-point analysis of all possible scores and disease-free survival (DFS) in patients receiving any adjuvant endocrine therapy. Using this definition, 71% of all tumors were determined to be ER-positive by IHC, and the level of agreement with the LBA was 86%. In multivariate analyses of patients receiving adjuvant endocrine therapy alone, ER status determined by IHC was better than that determined by the LBA at predicting improved DFS (hazard ratios/P = 0.474/.0008 and 0.707/.3214, respectively) and equivalent at predicting overall survival (0.379/.0001 and 0.381/.0003, respectively).
CONCLUSIONS
IHC is superior to the LBA for assessing ER status in primary breast cancer because it is easier, safer, and less expensive, and has an equivalent or better ability to predict response to adjuvant endocrine therapy.
Publication
Journal: Journal of Molecular Biology
February/5/2002
Abstract
Orthologs are genes in different species that originate from a single gene in the last common ancestor of these species. Such genes have often retained identical biological roles in the present-day organisms. It is hence important to identify orthologs for transferring functional information between genes in different organisms with a high degree of reliability. For example, orthologs of human proteins are often functionally characterized in model organisms. Unfortunately, orthology analysis between human and e.g. invertebrates is often complex because of large numbers of paralogs within protein families. Paralogs that predate the species split, which we call out-paralogs, can easily be confused with true orthologs. Paralogs that arose after the species split, which we call in-paralogs, however, are bona fide orthologs by definition. Orthologs and in-paralogs are typically detected with phylogenetic methods, but these are slow and difficult to automate. Automatic clustering methods based on two-way best genome-wide matches on the other hand, have so far not separated in-paralogs from out-paralogs effectively. We present a fully automatic method for finding orthologs and in-paralogs from two species. Ortholog clusters are seeded with a two-way best pairwise match, after which an algorithm for adding in-paralogs is applied. The method bypasses multiple alignments and phylogenetic trees, which can be slow and error-prone steps in classical ortholog detection. Still, it robustly detects complex orthologous relationships and assigns confidence values for both orthologs and in-paralogs. The program, called INPARANOID, was tested on all completely sequenced eukaryotic genomes. To assess the quality of INPARANOID results, ortholog clusters were generated from a dataset of worm and mammalian transmembrane proteins, and were compared to clusters derived by manual tree-based ortholog detection methods. This study led to the identification with a high degree of confidence of over a dozen novel worm-mammalian ortholog assignments that were previously undetected because of shortcomings of phylogenetic methods.A WWW server that allows searching for orthologs between human and several fully sequenced genomes is installed at http://www.cgb.ki.se/inparanoid/. This is the first comprehensive resource with orthologs of all fully sequenced eukaryotic genomes. Programs and tables of orthology assignments are available from the same location.
Publication
Journal: Journal of Biological Chemistry
September/25/1991
Abstract
Staurosporine is the most potent inhibitor of protein kinase C (PKC) described in the literature with a half-maximal inhibitory concentration (IC50) of 10 nM. Nevertheless, this natural product is poorly selective when assayed against other protein kinases. In order to obtain specific PKC inhibitors, a series of bisindolylmaleimides has been synthesized. Structure-activity relationship studies allowed the determination of the substructure responsible for conferring high potency and lack of selectivity in the staurosporine molecule. Several aminoalkyl bisindolylmaleimides were found to be potent and selective PKC inhibitors (IC50 values from 5 to 70 nM). Among these compounds GF 109203X has been chosen for further studies aiming at the characterization of this chemical family. GF 109203X was a competitive inhibitor with respect to ATP (Ki = 14 +/- 3 NM) and displayed high selectivity for PKC as compared to five different protein kinases. We further determined the potency and specificity of GF 109203X in two cellular models: human platelets and Swiss 3T3 fibroblasts. GF 109203X efficiently prevented PKC-mediated phosphorylations of an Mr = 47,000 protein in platelets and of an Mr = 80,000 protein in Swiss 3T3 cells. In contrast, in the same models, the PKC inhibitor failed to prevent PKC-independent phosphorylations. GF 109203X inhibited collagen- and alpha-thrombin-induced platelet aggregation as well as collagen-triggered ATP secretion. However, ADP-dependent reversible aggregation was not modified. In Swiss 3T3 fibroblasts, GF 109203X reversed the inhibition of epidermal growth factor binding induced by phorbol 12,13-dibutyrate and prevented [3H] thymidine incorporation into DNA, only when this was elicited by growth promoting agents which activate PKC. Our results illustrate the potential of GF 109203X as a tool for studying the involvement of PKC in signal transduction pathways.
Publication
Journal: Journal of Aging and Health
June/8/1993
Abstract
Brief measurement devices can alleviate respondent burden and lower refusal rates in surveys. This article reports on a field test of two shorter forms of the Center for Epidemiological Studies Depression (CES-D) symptoms index in a multisite survey of persons 65 and older. Factor analyses demonstrate that the briefer forms tap the same symptoms dimensions as does the original CES-D, and reliability statistics indicate that they sacrifice little precision. Simple transformations are presented to how scores from the briefer forms can be compared to those of the original.
Publication
Journal: Science
September/5/2006
Abstract
Years of intensive investigation have yielded a sophisticated understanding of long-term potentiation (LTP) induced in hippocampal area CA1 by high-frequency stimulation (HFS). These efforts have been motivated by the belief that similar synaptic modifications occur during memory formation, but it has never been shown that learning actually induces LTP in CA1. We found that one-trial inhibitory avoidance learning in rats produced the same changes in hippocampal glutamate receptors as induction of LTP with HFS and caused a spatially restricted increase in the amplitude of evoked synaptic transmission in CA1 in vivo. Because the learning-induced synaptic potentiation occluded HFS-induced LTP, we conclude that inhibitory avoidance training induces LTP in CA1.
Publication
Journal: Journal of Clinical Investigation
February/9/2005
Abstract
Macrophages perform both injury-inducing and repair-promoting tasks in different models of inflammation, leading to a model of macrophage function in which distinct patterns of activation have been proposed. We investigated macrophage function mechanistically in a reversible model of liver injury in which the injury and recovery phases are distinct. Carbon tetrachloride---induced liver fibrosis revealed scar-associated macrophages that persisted throughout recovery. A transgenic mouse (CD11b-DTR) was generated in which macrophages could be selectively depleted. Macrophage depletion when liver fibrosis was advanced resulted in reduced scarring and fewer myofibroblasts. Macrophage depletion during recovery, by contrast, led to a failure of matrix degradation. These data provide the first clear evidence that functionally distinct subpopulations of macrophages exist in the same tissue and that these macrophages play critical roles in both the injury and recovery phases of inflammatory scarring.
Publication
Journal: Journal of Clinical Investigation
June/13/2006
Abstract
Uncontrolled mucosal immunity in the gastrointestinal tract of humans results in chronic inflammatory bowel disease (IBD), such as Crohn disease and ulcerative colitis. In early clinical trials as well as in animal models, IL-12 has been implicated as a major mediator of these diseases based on the ability of anti-p40 mAb treatment to reverse intestinal inflammation. The cytokine IL-23 shares the same p40 subunit with IL-12, and the anti-p40 mAbs used in human and mouse IBD studies neutralized the activities of both IL-12 and IL-23. IL-10-deficient mice spontaneously develop enterocolitis. To determine how IL-23 contributes to intestinal inflammation, we studied the disease susceptibility in the absence of either IL-23 or IL-12 in this model, as well as the ability of recombinant IL-23 to exacerbate IBD induced by T cell transfer. Our study shows that in these models, IL-23 is essential for manifestation of chronic intestinal inflammation, whereas IL-12 is not. A critical target of IL-23 is a unique subset of tissue-homing memory T cells, which are specifically activated by IL-23 to produce the proinflammatory mediators IL-17 and IL-6. This pathway may be responsible for chronic intestinal inflammation as well as other chronic autoimmune inflammatory diseases.
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