Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Conversation analysis”

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 973 records · Page 54Linked to original sources
PubMed1997

Recombination and gene flux caused by gene conversion and crossing over in inversion heterokaryotypes.

A theoretical analysis of the effects of inversions on recombination and gene flux between arrangements caused by gene conversion and crossing over was carried out. Two different mathematical models of recombination were used: the Poisson model (without interference) and the Counting model (with interference). The main results are as follows. (1) Recombination and gene flux are highly site-dependent both inside and outside the inverted regions. (2) Crossing over overwhelms gene conversion as a cause of gene flux in large inversions, while conversion becomes relatively significant in short inversions and in regions around the breakpoints. (3) Under the Counting model the recombination rate between two markers depends strongly on the position of the markers along the inverted segment. Two equally spaced markers in the central part of the inverted segment have less recombination than if they are in a more extreme position. (4) Inversions affect recombination rates in the univerted regions of the chromosome. Recombination increases in the distal segment and decreases in the proximal segment. These results provide an explanation for a number of observations reported in the literature. Because inversions are ubiquitous in the evolutionary history of many Drosophila species, the effects of inversions on recombination are expected to influence DNA variation patterns.

Animals↗
PubMed1992

Farnesylcysteine, a constituent of the alpha and beta subunits of rabbit skeletal muscle phosphorylase kinase: localization by conversion to S-ethylcysteine and by tandem mass spectrometry.

The primary structure of the alpha and beta subunits of phosphorylase kinase reveals that both proteins contain a carboxyl-terminal CA1A2X motif (where C is cysteine, A1 and A2 are aliphatic amino acids, and X is an uncharged amino acid), the recognition signal for a protein polyisoprenyltransferase. The product, a polyisoprenylated cysteine, can be detected by phenylthiocarbamoylamino acid analysis and by microsequencing following conversion to S-ethylcysteine. Mass spectrometry confirms a covalently linked farnesyl residue in both subunits. Tandem mass spectrometry localizes these modifications at the cysteine residues present in the carboxyl-terminal CAMQ and CLVS sequences of the alpha and beta subunits, respectively. Membrane association of phosphorylase kinase, probably mediated by these farnesyl residues, is discussed.

Amino Acid Sequence↗
PubMed1988

A developmental-genetic analysis of aggressive behavior in mice (Mus musculus): III. Behavioral mediation by heightened reactivity or immobility?

This research was designed to investigate development and behavioral mediation in lines of ICR mice that have been selectively bred for aggressive behavior. General behavioral reactivity and behavioral immobility have been implicated as potential mediators by prior analyses of preattack interactions. To evaluate the separate roles of these dispositions, the emergence of attacks in genetically selected lines was tracked for 11 years by three levels of analysis: over successive generations, over development, and over dyadic interactions. Convergent outcomes were observed in all three levels with respect to two findings: (a) Robust line differences were obtained in attack behaviors, and (b) strong associations were found between line differences in attacks and line differences in behavioral immobility. Conversely, all three levels of analysis indicated a weak and inconsistent association between line differences in attacks and measures of social and nonsocial reactivity.

Aggression↗
PubMed1984

Role of mothers' expansions in stimulating children's language production.

Mothers' expansions were examined for their role in structuring conversational contributions and facilitating spontaneous imitations and productions of two-term semantic relations not previously used by their children. The subjects were four 2-year-old boys in late Stage 1 of linguistic development and their mothers. The investigation consisted of two studies. Study 1, a descriptive analysis of mother-child conversation, showed a contingent relationship between mothers' expansions and their children's use of spontaneous imitations. Study 2, an experimental procedure using a multiple baseline treatment design, showed that an increase in the mothers' expansions was systematically related to an increase in the children's initial spontaneous imitations of two-term semantic relations. Results also indicated that following the increase in spontaneous imitations, spontaneous productions of the two-term relations increased and were maintained, whereas spontaneous imitations subsequently decreased.

Child, Preschool↗
PubMed2002

Intracrine induction of 11beta-hydroxysteroid dehydrogenase type 1 expression by glucocorticoid potentiates prostaglandin production in the human chorionic trophoblast.

Glucocorticoids are involved in the modulation of the release of parturition hormones from the fetal membranes and placenta, where their actions are determined by the prereceptor glucocorticoid metabolizing enzyme 11beta-hydroxysteroid dehydrogenase (11beta-HSD). Two distinct isozymes of 11beta-HSD have been characterized. In the fetal membranes, 11beta-HSD1 is the predominate isozyme; it converts biologically inert 11-ketone glucocorticoid metabolites into active glucocorticoids. Sequence analysis of the cloned 11beta-HSD1 gene revealed a putative glucocorticoid response element in the promoter region. However, whether glucocorticoids modulate 11beta-HSD1 expression in the fetal membranes is unknown. In this study, 11beta-HSD1 and glucocorticoid receptor (GR) were coexpressed in the chorionic trophoblast. Radiometric conversion assay and Northern blot analysis revealed that both 11beta-HSD1 reductase activity and mRNA levels were increased by dexamethasone (1 microM, 0.1 microM) in the cultured chorionic trophoblast, and the effects were blocked by GR antagonist RU486 (1 microM). Prior induction of 11beta-HSD1 by dexamethasone potentiated the subsequent stimulation of prostaglandin H synthetase 2 expression and secretion of prostaglandin E(2) by cortisone in the chorionic trophoblast. There is colocalization of 11beta-HSD1 and GR in the chorionic trophoblast. By binding to GR, glucocorticoids induce the expression of 11beta-HSD1 by a possible intracrine mechanism, thereby amplifying the actions of glucocorticoids on prostaglandin production in the fetal membranes. This cascade of events initiated by glucocorticoids may play an important role in the positive feed-forward mechanisms of labor.

11-beta-Hydroxysteroid Dehydrogenase Type 1↗
PubMed1990

Chemical synthesis, absolute configuration, and stereochemistry of formation of 10-hydroxywarfarin: a major oxidative metabolite of (+)-(R)-warfarin from hepatic microsomal preparations.

The synthesis of a diastereomerically pure 10-hydroxywarfarin [4-hydroxy-3-(2-hydroxy-3-oxo-1-phenylbutyl)-2H-1 benzopyran-2-one] was accomplished in three steps from racemic warfarin. The relative configuration of the synthetic product was established by conversion to a cyclic derivative followed by NMR and X-ray diffraction analysis. Absolute stereochemistry was determined by enzymatic conversion of either of the pure enantiomers of warfarin to a 10-hydroxy metabolite of known relative configuration. Metabolic formation of 10-hydroxywarfarin was studied using hepatic microsomal preparations from female rats and man. The formation of 10-hydroxywarfarin catalyzed by hepatic microsomes from both dexamethasone-treated rats and man was highly stereoselective [(R)/(S): 3.4-9.0] for (R)-warfarin. In contrast, little stereoselectivity was observed in reactions catalyzed by untreated rat liver microsomes. The resultant stereochemistry at the site of oxidation was also found to be highly dependent on substrate stereochemistry. (R)-Warfarin gave (9R;10S)-10-hydroxywarfarin with only a trace of the (9R;10R) isomer irrespective of which enzyme preparation was used for catalysis, while (S)-warfarin gave (9S;10R)-10-hydroxywarfarin with only a trace of the (9S;10S) isomer, again irrespective of which enzyme preparation was used for catalysis.

Animals↗
PubMed2005

A natural CYP2B6 TATA box polymorphism (-82T--> C) leading to enhanced transcription and relocation of the transcriptional start site.

We investigated the impact of promoter polymorphisms on transcription of the human CYP2B6 gene. In total, 98 DNA samples from white persons from a previously characterized liver bank were sequenced throughout 2.3 kilobases of upstream sequence and haplotype structures were determined using additional coding sequence information. HepG2 cells and primary rat and human hepatocytes were transfected with luciferase reporter gene constructs driven by 2033 base pairs (bp) of the most frequent promoter variants. The novel haplotype *22 (-1848C--> A, -801G--> T, -750T--> C, and -82T--> C) showed 3- to 9-fold enhanced transcriptional activity in all transfected cells. Constructs containing single mutations surprisingly revealed -82T--> C, predicted to disrupt a putative TATA box, to be alone responsible for this effect. In silico analysis and electrophoretic mobility shift assay demonstrated conversion of the putative TATA box into a functional CCAAT/enhancer-binding protein binding site. Analysis of transcriptional start sites showed the mutant promoter to be transcribed from a start site located approximately 30 bp downstream of the wild-type start site, consistent with the use of a noncanonical TATA box at -55 bp. Median CYP2B6 mRNA expression and bupropion hydroxylase activity as a selective marker of CYP2B6 catalytic activity were approximately 2-fold higher in livers genotyped -82TC as in those genotyped -82TT (20.4 versus 9.8 arbitrary units, p = 0.007, and 201.8 versus 106.7 pmol/mg/min, p = 0.042, respectively). This promoter polymorphism thus contributes to CYP2B6 functional variability and represents a novel mechanism by which mutations can enhance transcription. Furthermore, a detailed interspecies comparison of CYP2B promoters and transcriptional start sites provided novel insights into evolutionary relationships.

Animals↗
PubMed2006

Transformation of phenol, catechol, guaiacol and syringol exposed to sodium hypochlorite.

Germs, xenobiotics and organic matter that influence the colour, turbidity and organoloeptic properties of water are removed by chlorination. Unfortunately, chlorine oxidants including sodium hypochlorite, used in water treatment induce processes that partly convert the treated compounds to unwanted chlorinated derivatives. The purpose of this work was to analyse the efficiency of transformation of phenol, catechol, guaiacol and syringol exposed to sodium hypochlorite and determine the intermediates formed during oxidative conversion of these compounds. The analysis was performed in aerobic conditions, both in acidic (pH 4.0) and alkaline (pH 8.0) medium. The effectiveness of transformation was slightly higher in acidic in comparison to alkaline conditions. Some chlorophenols, such as 2-chlorophenol, 2,4-dichlorophenol, 2,4,5-trichlorophenol and pentachlorophenol were determined as the products of phenol conversion. Chlorophenols were also formed during catechol, guaiacol and syringol transformation by replacement of hydroxy and methoxy residues by chlorine atoms. Moreover, some chlorocatechols and chlorinated methoxyphenols were determined during catechol and methoxyphenols transformations. Higher concentrations of chlorinated compounds were observed in the alkaline environment during phenol transformation. Conversion of catechol and methoxyphenols generated higher amounts of chlorinated intermediates in the acidic medium. In samples carboxylic acids like acetic and formic acids were determined. The formation of these compounds was the result of the cleavage of aromatic structure of phenols.

Catechols↗
PubMed1985

Kinetic study on the initial stage of the fibrinogen-fibrin conversion by thrombin. (IV). Effects of heparin and its analogues.

From kinetic analysis on the initial stage of the fibrinogen-fibrin conversion catalyzed by thrombin, inhibition constants, Kip, of heparin and heparin analogues were obtained by the turbidimetrical method. The inhibitory effect per unit amount in weight of heparin and heparin analogues increased generally with decreasing concentration, and their modes of inhibition changed. In the fibrinogen and thrombin system, heparin and its analogues were observed to act as noncompetitive inhibitors at high concentrations, where the inhibition constant of heparin was 3.91 X 10(-6) M. At low concentrations below 10(-5) M, both heparin and dextran sulphate acted as hyperbolic competitive inhibitors of thrombin, and Kip of heparin was 1.07 X 10(-8) M, which was measured at heparin concentrations below ca. 10(-8) M. It was presumed that heparin has electrostatic interaction with the active site of thrombin or the binding site located near the active site of thrombin.

Animals↗
PubMedDate not supplied

Identification of essential loops and residues of glucosyltransferase V (GtrV) of Shigella flexneri.

Lipopolysaccharide (LPS), particularly the O-antigen component, is one of many virulence determinants necessary for Shigella flexneri pathogenesis. O-antigen modification is mediated by glucosyltransferase (gtr) genes encoded by temperate serotype-converting bacteriophages. The gtrV and gtrX genes encode the GtrV and GtrX glucosyltransferases, respectively. These are integral membrane proteins, which catalyze the transfer of a glucosyl residue via an alpha1,3 linkage to rhamnose II and rhamnose I of the O-antigen unit. This mediates conversion of S. flexneri serotype Y to serotype 5a and X, respectively. Essential regions in the topology of GtrV protein were identified by in vivo recombination and a PCR-mediated approach. A series of GtrX-GtrV and GtrV-GtrX chimeric proteins were constructed based on the fact that GtrV and GtrX share sequence similarity. Analysis of their respective serotype conversion abilities led to the identification of two important periplasmic loops: loops No 2 and No 10 located in the N- and C-termini, respectively. Within these two loops, three conserved motifs were identified; two in loop No 2 and one in loop No 10. These conserved motifs contain acidic residues which were shown to be critical for GtrV function.

Amino Acid Sequence↗
PubMed2006

Evaluation of chemical and photochemical oxidation processes for degradation of phosmet on lowbush blueberries (Vaccinium angustifolium).

Chemical and photochemical oxidation processes were evaluated for their ability to degrade residual phosmet on lowbush blueberries and for their role in the conversion of phosmet to phosmet oxon--a toxic metabolite of phosmet. Chemical processes included 1 ppm of aqueous ozone, 1% hydrogen peroxide, 100 ppm of chlorine, and UV, whereas photochemical processes included hydrogen peroxide/UV, chlorine/UV, and ozone/hydrogen peroxide/UV. Phosmet applied as Imidan 2.5EC under laboratory conditions resulted in a mean residual concentration of 44.4 ppm, which was significantly degraded (p < 0.05) by ozone and chlorine, yielding reductions of 57.7 and 46%, respectively. Interaction between phosmet (Imidan 2.5EC) and any chemical or photochemical treatment did not result in conversion to phosmet oxon. Residual analysis of commercially grown blueberries revealed mean phosmet (Imidan 70W) levels of 10.65 ppm and phosmet oxon levels of 12.49 ppm. Treatment of commercial blueberries resulted in significant reductions in phosmet regardless of treatment type; however, only UV, hydrogen peroxide/UV, and ozone treatments degraded phosmet (Imidan 70W) to less toxic metabolites and reduced phosmet oxon levels. Treatment-induced conversion of phosmet to phosmet oxon was noticeably influenced by variations between phosmet formulations. Acceleration of photochemical degradation by UV was not observed. Selective oxidation by ozone represents a significant postharvest process for degrading residual phosmet on lowbush blueberries.

Blueberry Plants↗
PubMed2003

Transcriptional regulation of protein complexes and biological pathways.

The cis-element profile (or cis-profile) of a gene refers to the collection of transcription factor binding sites (TFBS) regulating the transcription of the gene. Underlying the various published studies that attempt to discover cis-elements in the vicinity of co-expressed genes via pattern detection algorithms, there is an implicit assumption that a correlation exists between co-expressed genes and their cis-profiles. In this study, we show that the cis-similarity, defined as the proportion of shared TFBS between two cis-element profiles, is higher for functionally linked interacting proteins as well as for members of a signal transduction pathway. A similar analysis of the enzymes catalyzing the conversion of adjacent substrates to products in a collection of metabolic pathways, did not reveal higher cis-similarity. The analysis is based on three distinct sources of publicly available data, namely, 1) the BIND database of interacting proteins, 2) known interactions in NMDAR protein complex, 3) the apoptosis pathway and nine pathways related to metabolism of cofactors and vitamins all from KEGG. Additionally, we analyze the cis-element profiles of all the genes in the glutamate receptor (GR) sub-complex of NMDAR complex to detect a set of cis-elements that occur adjacent to a majority of the genes. We show that most of the corresponding transcription factors are known to be involved in GR regulation by comparing our findings with the published biomedical literature. In addition, we were able to detect transcripts whose gene products associate with GR by searching for transcripts that share the same regulatory signals as those detected for GR. This suggests a novel computational methodology for constructing high-order gene regulatory models and detecting co-regulated gene products.

Apoptosis↗
PubMed1996

The effect of ethoxyquin on tissue peroxidation and immune status of single comb White Leghorn cockerels.

The responses to supplementing the diet of Single Comb White Leghorn (SCWL) cockerels with ethoxyquin were tested on two parameters: 1) tissue peroxidation and 2) immune response. In the first experiment, three concentrations of supplemental ethoxyquin (0, 500, and 1,000 ppm) were added to a basal diet and fed to SCWL cockerels for 6 wk. Tissue peroxidation was assessed by measuring the thiobarbituric acid reactive substances (TBARS) concentration in the liver, kidney, heart, and spleen. The TBARS concentration in response to 500 ppm dietary ethoxyquin was significantly lower in the liver and spleen tissues, whereas in the kidneys, 1,000 ppm ethoxyquin significantly lowered TBARS. In a second experiment, four concentrations of ethoxyquin (0, 125, 500, and 1,000 ppm) were added to a basal diet and fed to SCWL cockerels for 8 wk. The primary and secondary immune response were assessed by determining antibody titers to the Newcastle disease virus using hemagglutination inhibition (HI) and ELISA. The HI and ELISA titers for the primary and secondary immune response were not significantly different from the control. Analysis of body weight, feed conversion, and organ weight revealed no statistically significant differences between treatments, although in the second experiment the dietary treatment of 1,000 ppm ethoxyquin resulted in significantly higher relative liver weight.

Analysis of Variance↗
PubMed2001

Does indirect speech promote nondirective genetic counseling? Results of a sociolinguistic investigation.

To date, research examining adherence to genetic counseling principles has focused on specific counseling activities such as the giving or withholding of information and responding to client requests for advice. We audiotaped 43 prenatal genetic counseling sessions and used data-driven, qualitative, sociolinguistic methodologies to investigate how language choices facilitate or hinder the counseling process. Transcripts of each session were prepared for sociolinguistic analysis of the emergent discourse that included studying conversational style, speaker-listener symmetry, directness, and other interactional patterns. Analysis of our data demonstrates that: 1) indirect speech, marked by the use of hints, hedges, and other politeness strategies, facilitates rapport and mitigates the tension between a client-centered relationship and a counselor-driven agenda; 2) direct speech, or speaking literally, is an effective strategy for providing information and education; and 3) confusion exists between the use of indirect speech and the intent to provide nondirective counseling, especially when facilitating client decision-making. Indirect responses to client questions, such as those that include the phrases "some people" or "most people," helped to maintain counselor neutrality; however, this well-intended indirectness, used to preserve client autonomy, may have obstructed direct explorations of client needs. We argue that the genetic counseling process requires increased flexibility in the use of direct and indirect speech and provide new insights into how "talk" affects the work of genetic counselors.

Decision Making↗
PubMed2005

Mechanism studies of the conversion of 13C-labeled n-butane on zeolite H-ZSM-5 by using 13C magic angle spinning NMR spectroscopy and GC-MS analysis.

By using 13C MAS NMR spectroscopy (MAS = magic angle spinning), the conversion of selectively 13C-labeled n-butane on zeolite H-ZSM-5 at 430-470 K has been demonstrated to proceed through two pathways: 1) scrambling of the selective 13C-label in the n-butane molecule, and 2) oligomerization-cracking and conjunct polymerization. The latter processes (2) produce isobutane and propane simultaneously with alkyl-substituted cyclopentenyl cations and condensed aromatic compounds. In situ 13C MAS NMR and complementary ex situ GC-MS data provided evidence for a monomolecular mechanism of the 13C-label scrambling, whereas both isobutane and propane are formed through intermolecular pathways. According to 13C MAS NMR kinetic measurements, both pathways proceed with nearly the same activation energies (E(a) = 75 kJ mol(-1) for the scrambling and 71 kJ mol(-1) for isobutane and propane formation). This can be rationalized by considering the intermolecular hydride transfer between a primarily initiated carbenium ion and n-butane as being the rate-determining stage of the n-butane conversion on zeolite H-ZSM-5.

Journal Article↗
PubMed1994

Gene dissection demonstrates that the Escherichia coli cysG gene encodes a multifunctional protein.

The C-terminus of the Escherichia coli CysG protein, consisting of amino acids 202-457, was expressed as a recombinant protein using gene dissection methodology. Analysis of the activity of this truncated protein, termed CysGA, revealed that it was able to methylate uroporphyrinogen III in the same S-adenosyl-L-methionine (SAM)-dependent manner as the complete CysG protein. However, this truncated protein was not able to complement E. coli cysG cells, thereby suggesting that the first 201 amino acids of the CysG protein had an enzymic activity associated with the conversion of dihydrosirohydrochlorin into sirohaem. Analysis of the N-terminus of the CysG protein revealed the presence of a putative pyridine dinucleotide binding site. When the purified CysG protein was incubated with NADP+, uroporphyrinogen III and SAM the enzyme was found to catalyse a coenzyme-mediated dehydrogenation to form sirohydrochlorin. The CysGA protein on the other hand showed no such coenzyme-dependent activity. Analysis of the porphyrinoid material isolated from strains harbouring plasmids containing the complete and truncated cysG genes suggested that the CysG protein was also involved in ferrochelation. The evidence presented in this paper suggests that the CysG protein is a multifunctional protein involved in SAM-dependent methylation, pyridine dinucleotide dependent dehydrogenation and ferrochelation.

Amino Acid Sequence↗
PubMed1997

Preoperative ultrasound to predict conversion in laparoscopic cholecystectomy.

Laparoscopic cholecystectomy (LC) is the established treatment for symptomatic cholelithiasis. With its decreased postoperative stay, it is being performed increasingly in short-stay or outpatient settings. It is particularly important to identify preoperative factors that may predict conversion to open cholecystectomy (OC) at LC, with its concomitantly prolonged hospital recovery. In this series of 738 patients, the ultrasound features of stone size, gallbladder wall thickness, diameter of the common bile duct, number of stones, and the appearance of a contracted gallbladder were assessed preoperatively in all patients. The overall conversion rate was 3.5% (26 of 738). By logistic regression analysis, factors found to increase significantly the risk of conversion were patient age > 70 years (p < 0.01), a stone at least 20 mm in diameter (p < 0.05), a gallbladder wall thicker than 4 mm (p < 0.05), a common bile duct wider than 6 mm (p < 0.05), and contracted gallbladder on ultrasound (p < 0.02). The number of stones in the gallbladder was not significant. Using these risk factors, it was possible to divide patients into high- and low-risk groups. The 118 patients in the high-risk group had 18 of the 26 conversions, for a conversion rate of 15.3%. The 620 patients in the low-risk group had eight of the 26 conversions, for a conversion rate of 1.3%. This low-risk subgroup represented 84% of the series of 738 LC procedures and may have been suitable for outpatient LC. Using preoperative ultrasound, it is possible to predict patients who are at low risk of conversion and are suitable for ambulatory surgery.

Age Factors↗
PubMed1998

Gene conversion disparity in yeast: its extent, multiple origins, and effects on allele frequencies.

The extent of disparity in gene conversion direction in yeast (Saccharomyces cerevisiae) is important for recombination mechanisms and for effects of conversion on allele frequencies in populations. An analysis of published and unpublished data demonstrates that yeast frequently shows significant and extensive conversion disparity, contrary to many published statements. All types of mutation--base-substitutions, frameshifts and longer deletions and additions--can show significant 6:2/2:6 and/or 5:3/3:5 disparity. There was little correlation between the occurrence of 6:2/2:6 and 5:3/3:5 disparities; when both were significant, they were more often in opposite directions than in the same direction. Surprisingly, there was little correlation between a mutation's molecular nature and its disparity properties, which generally seem unpredictable. Disparity in yeast has multiple origins. From the equations discussed, all disparity types can be explained by one or more of: correction direction disparity, chromatid invasion disparity (including cases caused by different frequencies of double-strand breaks or gaps in nonsister homologous chromatids), strand invasion disparity, and different correction frequencies for the two types of mispair for a heterozygous mutation. Levels of overall disparity and of conversion frequency mean that conversion must often change allele frequencies in sexually reproducing yeast populations.

Alleles↗