Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Promoter dynamics”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 127 records · Page 7Linked to original sources
PubMed2000

Effect of PEEP on work of breathing in mechanically ventilated COPD patients.

OBJECTIVE: To study the effects of PEEP on the inspiratory work done per breath on the respiratory system (W(I,rs)) in patients with chronic obstructive pulmonary disease (COPD). DESIGN: Physiological study. SETTING: Fourteen-bed Medical ICU of a 1,000-bed teaching tertiary hospital. PATIENTS AND PARTICIPANTS: Ten patients with COPD intubated and mechanically ventilated for acute respiratory failure. INTERVENTIONS: PEEP of 0 (ZEEP), 5, 10, and 15 cm H2O were applied randomly and measurements done at the end of a 15-20 min period. MEASUREMENTS AND RESULTS: Using the rapid airway occlusion technique during constant flow inflation, we partitioned W(I,rs) into its static and dynamic components. On ZEEP, the mean +/- SD values of W(I,rs) amounted to 15.1 +/- 5.7 cm H2O x 1. With increasing PEEP, W(I,rs) was significantly reduced to 12.6 +/- 5.7, 11.1 +/- 4.1, and 10.4 +/- 2.8 cm H2O x 1 at PEEP of 5, 10, and 15 cm H2O, respectively (P < 0.05). This reduction was entirely due to the decline of the work due to intrinsic PEEP (PEEPi) and was abolished when the applied PEEP counterbalanced PEEPi. The other components of W(I,rs) were not affected by PEEP. By increasing PEEP up to the level of PEEPi on ZEEP, no further increase in end-expiratory lung volume was observed. CONCLUSIONS: In COPD patients the application of PEEP levels close to PEEPi can substantially reduce W(I,rs) without promoting further dynamic pulmonary hyperinflation.

Analysis of Variance↗
PubMed1996

Narp, a novel member of the pentraxin family, promotes neurite outgrowth and is dynamically regulated by neuronal activity.

Stimulus-linked RNA and protein synthesis is required for establishment of long-term neuroplasticity. To identify molecular mechanisms underlying long-term neuroplasticity, we have used differential cDNA techniques to clone a novel immediate-early gene (IEG) that is rapidly induced in neurons of the hippocampus and cortex by physiological synaptic activity. Analysis of the deduced amino acid sequence indicates homology to members of the pentraxin family of secreted lectins that include C-reactive protein and serum amyloid P component. Regions of homology include an 8 amino acid "pentraxin signature" sequence and a characteristic pentraxin calcium-binding domain. We have termed this gene and the encoded protein Narp (from neuronal activity-regulated pentraxin). Biochemical analyses confirm the presence of a functional signal sequence, and Narp is secreted by transfected COS-1 cells in culture. Additionally, Narp binds to agar matrix in a calcium-dependent manner consistent with the lectin properties of the pentraxin family. When cocultured with Narp-secreting COS-1 cells, neurons of cortical explants exhibit enhanced growth of neuronal dendritic processes. Neurite outgrowth-promoting activity is also observed using partially purified Narp and can be specifically immunodepleted, demonstrating that Narp is the active principle. Narp is fully active at a concentration of approximately 40 ng/ml, indicating a potency similar to known peptide growth factors. Because Narp is rapidly regulated by neuronal activity, its lectin and growth-promoting activities are likely to play role in the modification of cellular properties that underlie long-term plasticity.

Amino Acid Sequence↗
PubMed1997

Muscarinic modulation of the oscillatory and repetitive firing properties of entorhinal cortex layer II neurons.

Neurons in layer II of the entorhinal cortex (EC) are key elements in the temporal lobe memory system because they integrate and transfer into the hippocampal formation convergent sensory input from the entire cortical mantle. EC layer II also receives a profuse cholinergic innervation from the basal forebrain that promotes oscillatory dynamics in the EC network and may also implement memory function. To understand the cellular basis of cholinergic actions in EC, we investigated by intracellular recording in an in vitro rat brain slice preparation the muscarinic modulation of the electroresponsive properties of the two distinct classes of medial EC layer II projection neurons, the stellate cells (SCs) and non-SCs. In both SCs and non-SCs, muscarinic receptor activation with carbachol (CCh, 10-50 microM) caused atropine-sensitive (300 nM) membrane depolarization. In SCs, the CCh-induced membrane depolarization was associated with subthreshold membrane potential oscillations and "spike cluster" discharge, which are typically expressed by these cells on depolarization. CCh, however, caused a decrease of the dominant frequency of the membrane potential oscillations from 9.2 +/- 1.1 (SD) Hz to 6.3 +/- 1.1 Hz, as well as a decrease of the intracluster firing frequency from 18.1 +/- 1.7 Hz to 13.6 +/- 1.3 Hz. In addition, spike cluster discharge was less robust, and the cells tended to shift into tonic firing during CCh. In contrast to SCs, in non-SCs, CCh drastically affected firing behavior by promoting the development of voltage-dependent, long-duration (1-5 s) slow bursts of action potentials that could repeat rhythmically at slow frequencies (0.2-0.5 Hz). Concomitantly, the slow afterhyperpolarization (sAHP) was replaced by long-lasting plateau postdepolarizations. In both SCs and non-SCs, CCh also produced conspicuous changes on the action potential waveform and its afterpotentials. Notably, CCh significantly decreased spike amplitude and rate of rise, which suggests muscarinic modulation of a voltage-dependent Na+ conductance. Finally, we also observed that whereas CCh abolished the sAHP in both SCs and non-SCs, the membrane-permeant analogues of adenosine 3',5'-cyclic monophosphate, 8-(4-chlorophenylthio)-adenosine-cyclic monophosphate and 8-bromo-adenosine-cyclic-monophosphate, abolished the sAHP in SCs but not in non-SCs. The data demonstrate that cholinergic modulation further differentiates the intrinsic electroresponsiveness of SCs and non-SCs, and add support to the presence of two parallel processing systems in medial EC layer II that could thereby differentially influence their hippocampal targets. The results also indicate an important role for the cholinergic system in tuning the oscillatory dynamics of entorhinal neurons.

Action Potentials↗
PubMed1989

[Control of diarrheal diseases in Mexico and Latin America].

Oral rehydration therapy (ORT), has been considered the major advance in the treatment of the diarrheal diseases, and has been the single most important factor in the decrease of mortality and decreased morbidity in childhood diarrheal. ORT, is not limited to the administration of oral rehydration solution; it also includes feeding techniques and community education and participation. In order to promote ORT, national programs have been developed and promoted in educational centers in strategic areas of the Latin America countries, where medical and paramedical staff attend. In México there have been two national surveys to evaluate the ORT program. This policy has allowed for participating countries to reduce the cost of treatment of diarrheal disease.

Child, Preschool↗
PubMed2000

Taxol reduces cytosolic E-cadherin and beta-catenin levels in nasopharyngeal carcinoma cell line TW-039: cross-talk between the microtubule- and actin-based cytoskeletons.

Taxol affects microtubule dynamics by promoting microtubule assembly. To obtain a better insight into possible cross-talk between the microtubule- and actin-based cytoskeletons, we studied the short-term effects of Taxol treatment on the expression of actin and the E-cadherin/catenin complex in the nasopharyngeal carcinoma cell line TW-039 using immunofluorescence, immunoprecipitation, and immunoblotting methods. Morphologic changes in actin filaments, including ventral actin clumps and perijunctional actin blebs, were seen at Taxol concentrations > or =1 microM. Levels of detergent-soluble E-cadherin fell to 53% or 58% compared to controls in cells treated, respectively, with 1 or 5 microM Taxol, while levels of detergent-soluble beta-catenin fell to 76% or 74%. Levels of the detergent-soluble pool of alpha- and gamma-catenin and the detergent-insoluble pool of the E-cadherin/catenin complex were unchanged by Taxol treatment and no significant difference was seen in the levels of adenomatous polyposis coli or glycogen synthase-3beta or tyrosine phosphorylation patterns. These results suggest that modulation of microtubule dynamics by Taxol may have effects on the expression of actin and the cytosolic E-cadherin and beta-catenin in nasopharyngeal carcinoma cells through pathways not involving the phosphorylation of beta-catenin.

Actins↗
PubMed1991

Dynamics of activation of a galactose-inducible promoter in Saccharomyces cerevisiae.

We have investigated the dynamics of accumulation of the Escherichia coli beta-galactosidase (beta-gal) under the control of a promoter containing the galactose-inducible upstream activating sequence (UASG) in single Saccharomyces cerevisiae cells. The accumulation of beta-gal in single cells following the addition of the inducer, galactose, was determined using an in situ combined DNA and immunofluorescent stain in conjunction with flow cytometry. Two strains were studied, D603/2i, which has two copies of the galactose-inducible fusion gene integrated into its genome, and D603/pLGSD5, which carries a 2 microns-based plasmid containing the fusion gene. Flow cytometry results indicate that accumulation of beta-gal within the first three hours following the addition of galactose is dependent on cell cycle position. Two proposed mechanisms explaining this observed behavior are (1) the cell-cycle-dependent synthesis of the fusion protein or (2) the unequal partitioning of the protein at cell division between mother and daughter cells.

Cell Cycle↗
PubMed1986

[New concepts in mental health].

To what extent can one speak to-day of new concepts in the mental health field? There have existed for a long-time (since, for example, the Mental Hygiene Movement and the tendency Preventive Psychiatry in the United States) new programmes for the administration of care which aim at going beyond the 'repair model' (Goffman) of classical psychological medicine, and at developing a 'positive concept' of health (after William A. White in 1930). In the same spirit, psychoanalysis has promoted a dynamic concept of psychic disturbance which transcends the static opposition of health and illness. Finally, the insistence on systematic prevention of risks also follows the tendency to transcend the medical relationship. Thus, the conditions for bringing about, conserving and developing mental health have long ceased to be susceptible to thinking out from the base of clinical psychiatric concepts. These important transformations in the conceptions of mental health do not, however, guarantee their establishment in practice. We have chosen to emphasize here the point of view of the application (or non-application) of 'new concepts' in effective policies, rather dealing only with the theoretical text from which they have emerged, or declarations of intention that proclaim their merits. This article attempts firstly an evaluation of the reform movements that have developed since the end of the Second World War, mainly in the United States and in France with the following question as point of departure: "To what extent have modern mental health policies been innovative in relation to classical psychiatry dominated by a medical conception of mental health, that is to say a model that is "repair-oriented" or curative rather than positive or preventive"? Firstly, the achievements of the Community Health Centres in the United States and the Policy of the Sector (politique de secteur) in France is analysed. In both cases the 'theoretical' programmes of the promoters are compared to that which has been accomplished in fact. What, concretely, has happened to the will to "enlarge the conception of mental health to include concepts that no longer include mental disorder", as proclaimed by Leonard J. Duhl in summing up the spirit of the Community Mental Health Centres and Retardation Act? The article attempts this evaluation on a three-fold level: new theoretical models envisaged, new forms of intervention put into practice and the institutional transformations that have been introduced during the last 30 years.(ABSTRACT TRUNCATED AT 400 WORDS)

Community Mental Health Services↗
PubMed2003

Genes encoding a cellulosic polymer contribute toward the ecological success of Pseudomonas fluorescens SBW25 on plant surfaces.

Pseudomonas fluorescens SBW25 is a Gram-negative bacterium that grows in close association with plants. In common with a broad range of functionally similar bacteria it plays an important role in the turnover of organic matter and certain isolates can promote plant growth. Despite its environmental significance, the causes of its ecological success are poorly understood. Here we describe the development and application of a simple promoter trapping strategy (IVET) to identify P. fluorescens SBW25 genes showing elevated levels of expression in the sugar beet rhizosphere. A total of 25 rhizosphere-induced (rhi) fusions are reported with predicted roles in nutrient acquisition, stress responses, biosynthesis of phytohormones and antibiotics. One rhi fusion is to wss, an operon encoding an acetylated cellulose polymer. A mutant carrying a defective wss locus was competitively compromised (relative to the wild type) in the rhizosphere and in the phyllosphere, but not in bulk soil. The rhizosphere-induced wss locus therefore contributes to the ecological performance of SBW25 in the plant environment and supports our conjecture that genes inactive in the laboratory environment, but active in the wild, are likely to be determinants of fitness in natural environments.

Beta vulgaris↗
PubMed2004

The role of stathmin in the regulation of the cell cycle.

Stathmin is the founding member of a family of proteins that play critically important roles in the regulation of the microtubule cytoskeleton. Stathmin regulates microtubule dynamics by promoting depolymerization of microtubules and/or preventing polymerization of tubulin heterodimers. Upon entry into mitosis, microtubules polymerize to form the mitotic spindle, a cellular structure that is essential for accurate chromosome segregation and cell division. The microtubule-depolymerizing activity of stathmin is switched off at the onset of mitosis by phosphorylation to allow microtubule polymerization and assembly of the mitotic spindle. Phosphorylated stathmin has to be reactivated by dephosphorylation before cells exit mitosis and enter a new interphase. Interfering with stathmin function by forced expression or inhibition of expression results in reduced cellular proliferation and accumulation of cells in the G2/M phases of the cell cycle. Forced expression of stathmin leads to abnormalities in or a total lack of mitotic spindle assembly and arrest of cells in the early stages of mitosis. On the other hand, inhibition of stathmin expression leads to accumulation of cells in the G2/M phases and is associated with severe mitotic spindle abnormalities and difficulty in the exit from mitosis. Thus, stathmin is critically important not only for the formation of a normal mitotic spindle upon entry into mitosis but also for the regulation of the function of the mitotic spindle in the later stages of mitosis and for the timely exit from mitosis. In this review, we summarize the early studies that led to the identification of the important mitotic function of stathmin and discuss the present understanding of its role in the regulation of microtubules dynamics during cell-cycle progression. We also describe briefly other less mature avenues of investigation which suggest that stathmin may participate in other important biological functions and speculate about the future directions that research in this rapidly developing field may take.

Animals↗
PubMed1986

Binding of Drosophila heat-shock gene transcription factor to the hsp 70 promoter. Evidence for symmetric and dynamic interactions.

A Drosophila heat-shock gene transcription factor (HSTF) has been shown to bind to three domains upstream from the TATA homology on a hsp 70 gene. The domain closest to the TATA homology consists of two contiguous binding sites with different binding affinities. Occupancy of the TATA homology proximal site (site 1) coordinates HSTF binding to the neighboring site (site 2) in a cooperative manner (Topol, J., Ruden, D. M., and Parker, C. S. (1985) Cell 42, 527-537). We have used alkylation interference and protection experiments to determine which residues within the binding sites are closely contacted by the HSTF. The contacts inferred from these studies included the residues present in the consensus sequence found in all HSTF binding sites and exhibit rotational symmetry, suggestive of a multimeric HSTF. By employing a gel electrophoresis separation technique we were able to resolve two protein-DNA complexes consisting of site 1 occupancy (complex A) and sites 1 and 2 occupancy (complex B). Analysis of these discrete species reveals that a subset of contacts within site 1 change upon HSTF binding to site 2, suggesting that a conformational change in the protein-DNA complex occurs. Implications for the activation of heat-shock gene transcription are discussed.

Animals↗
PubMed1996

Mass media messages and reproductive behaviour in Nigeria.

This paper examines the effects of exposure to mass media messages promoting family planning on the reproductive behaviour of married women in Nigeria using cross-sectional data. Longitudinal data are also used to ensure that exposure to media messages pre-dates the indicators of reproductive behaviour. Cross-sectional analysis suggests that: (1) contraceptive use and intention are positively associated with exposure to mass media messages, and (2) women who are exposed to media messages are more likely to desire fewer children than those who are not exposed to such messages. Similarly, analysis of the longitudinal data shows that exposure to mass media messages is a significant predictor of contraceptive use. Thus, exposure to mass media messages about family planning may be a powerful tool for influencing reproductive behaviour in Nigeria.

Adolescent↗
PubMed2006

Ligand-induced dynamical regulation of NO conversion in Mycobacterium tuberculosis truncated hemoglobin-N.

Mycobacterium tuberculosis, the causative agent of human tuberculosis, is forced into latency by nitric oxide produced by macrophages during infection. In response to nitrosative stress M. tuberculosis has evolved a defense mechanism that relies on the oxygenated form of "truncated hemoglobin" N (trHbN), formally acting as NO-dioxygenase, yielding the harmless nitrate ion. X-ray crystal structures have shown that trHbN hosts a two-branched protein matrix tunnel system, proposed to control diatomic ligand migration to the heme, as the rate-limiting step in NO conversion to nitrate. Extended molecular dynamics simulations (0.1 micros), employed here to characterize the factors controlling diatomic ligand diffusion through the apolar tunnel system, suggest that O2 migration in deoxy-trHbN is restricted to a short branch of the tunnel, and that O2 binding to the heme drives conformational and dynamical fluctuations promoting NO migration through the long tunnel branch. The simulation results suggest that trHbN has evolved a dual-path mechanism for migration of O2 and NO to the heme, to achieve the most efficient NO detoxification.

Binding Sites↗
PubMed2001

Melatonin activates the peroxidase-oxidase reaction and promotes oscillations.

We have studied the peroxidase-oxidase reaction with NADH and O2 as substrates and melatonin as a cofactor in a semibatch reactor. We show for the first time that melatonin is an activator of the reaction catalyzed by enzymes from both plant and animal sources. Furthermore, melatonin promotes oscillatory dynamics in the pH range from 5 to 6. The frequency of the oscillations depends on the pH such that an increase in pH was accompanied by a decrease in frequency. Conversely, an increase in the flow rate of NADH or an increase in the average concentration of NADH resulted in an increase in oscillation frequency. Complex dynamics were not observed with melatonin as a cofactor. These results are discussed in relation to observations of oscillatory dynamics and the function of melatonin and peroxidase in activated neutrophils.

Animals↗
PubMed1999

ADF/cofilin weakens lateral contacts in the actin filament.

Observed in vivo motility rates can only be accounted for if the rate of actin filament treadmilling in cells is considerably greater than has been quantified for purified actin in vitro. ADF/cofilin is uniquely suited to promote actin dynamics in cells, owing to its remarkable ability to change actin filament structure. In earlier work we showed that human cofilin chanRges filament twist by about 5 degrees per subunit and suggested that this contributes to increased filament turnover. Our initial structural modeling provided some insights into how the longitudinal actin-actin contacts might be disrupted following cofilin-induced twisting. Here we present direct evidence that cofilin also disrupts lateral actin-actin contacts in the filament and suggest a model showing how this could contribute to cofilin's novel effects on actin filament dynamics and assembly.

Actin Depolymerizing Factors↗
PubMed2006

Clinical study on therapy of clearing hallow viscera in treating critical patients with gastro-enteric function disorder.

OBJECTIVE: To explore the clinical effect of therapy of clearing hallow viscera in treating critical patients with gastro-enteric function disorder (GEFD). METHODS: Retrospective analysis was carried out on 96 critical patients. They were 48 patients in the treated group treated with Dachengqi Decoction and 48 patients in the control group treated with Western medicine for promoting gastric dynamic force. The recovery rate, recovery time of gastro-enteric function, incidence rate and fatality rate of multiple organ dysfunction syndrome (MODS), as well as the level of plasma endotoxin (ET) before and after treatment between the two groups were compared. RESULTS: Comparison between the two groups in gastro-enteric function recovery rate (81.3% vs 45.8%), functional disorder sustaining time in patients who got recovered (1.2 +/- 0.3 days vs 4.0 +/- 1.1 days), incidence rate (29.17% vs 52.08%) and fatality rate (28.57% vs 56.00%) of MODS all showed significant difference (P < 0.05 or P < 0.01). The plasma level of ET after treatment in the treated group was significantly lower than that in the control group (P < 0.05). CONCLUSION: Therapy of clearing hallow viscera has a good effect in treating critical patients with gastro-enteric function disorder, and could reduce the incidence and fatality of MODS.

Adolescent↗
PubMed1990

Initiating breastfeeding: a world survey of the timing of postpartum breastfeeding.

A survey of the 'Human Relations Area Files' and ethnographic infant feeding literature from all cultures on the timing of infant feeding revealed that the practice of withholding colostrum from the infant was widespread. Data obtained from 120 cultures showed that in 50 cultures this delay in implementing breastfeeding was more than two days. In many groups, substitute prelacteal feeds were given, while in others, practices such as the use of purgatives exacerbated the risk of dehydration in the infant. The authors warn that nurses and midwives must be aware of the practice of withholding colostrum from the infant, and note that if a mother does not wish to breastfeed in the immediate postpartum, this does not necessarily mean that she wishes to bottle feed the infant.

Breast Feeding↗
PubMed1993

Collagen synthesis by fibroblasts cultured within a collagen sponge.

We prepared a collagen sponge made of type I and III bovine collagen, glycosaminoglycans (GAG) and chitosan. Fibroblasts grown within the collagen sponge express a sixfold increase of their collagen synthesis, compared with fibroblasts embedded in a collagen gel. Moreover, collagen synthesis is twice as high in the collagen sponge than in a monolayer culture. The collagen sponge culture system promotes a dynamic model for us to perform studies on the regulations of collagen synthesis. Increased collagen production within the collagen sponge leads fibroblasts to reconstitute their own extracellular matrix, which should be more physiological than a bovine collagen gel.

Animals↗
PubMed2005

The ABP-120 C-end region from Entamoeba histolytica interacts with sulfatide, a new lipid target.

EhABP-120 is the first filamin identified in the parasitic protozoan Entamoeba histolytica. Filamins are a family of cross-linking actin-binding proteins that promote a dynamic orthogonal web. They have been reported to interact directly with more than 30 cellular proteins and some phosphoinositides. The biochemical consequences of these interactions may have either positive or negative effects on the cross-linking function and also form a link between the cytoskeleton and plasma membrane. In this study, the EhABP-120 carboxy-terminal domain (END) was biochemically characterized. This domain was able to associate to 3-sulfate galactosyl ceramide, a new lipid target for a member of the filamin family. Also, the END domain was able to dimerize "in vitro." Molecular modeling analysis showed that the dimeric region is stabilized by a disulfide bond. Electrostatic and docking studies suggest that an electropositive concave pocket at the dimeric END domain interacts simultaneously with several sulfogalactose moieties of the sulfatide.

Amino Acid Sequence↗